involucrin and Psoriasis

The active vitamin D(3) regulates proliferation and differentiation of epidermal keratinocytes. Although topical application of steroid has been principal therapy for psoriasis, there occurs some side effects such as skin atropy, telangiectasis, and purpura. Recently topical vitamin D(3), tacalcitol, calcipotriol, and maxacalcitol, which avoid these side effects, are widely used for psoriasis. In this review, we discussed the mechanism, effect, and side effect of topical vitamin D(3) for psoriasis.

Topics: Administration, Topical; Cell Differentiation; Cell Division; Cholecalciferol; Combined Modality Therapy; Cyclosporine; Drug Therapy, Combination; ErbB Receptors; Humans; Keratinocytes; Ointments; Phosphorylation; Protein Precursors; Proto-Oncogene Proteins c-myc; Psoriasis; PUVA Therapy; Transglutaminases

Topics: Animals; Humans; Protein Kinase C; Protein Precursors; Psoriasis; Stem Cells

Epidermal keratinocytes in psoriatic lesions are characterized by activated Stat3, and increased levels of cytokines and growth factors that promote Stat3 activation have been found within psoriatic lesions. K5.Stat3C transgenic mice, in which keratinocytes express a constitutively active Stat3, develop psoriasis-like skin lesions. In this study, we examined whether STA-21, a small Stat3 inhibitor, could be useful in ameliorating the skin lesions not only in the model mouse but also in human psoriasis. Treatment with STA-21 markedly inhibited the cytokine-dependent nuclear translocation of Stat3 in normal human keratinocytes in vitro. Keratinocyte proliferation was inhibited by STA-21 in a dose-dependent manner through downregulation of c-Myc and cyclin D1, whereas involucrin, transglutaminase 1, and keratin 10 levels were upregulated. Topical application of STA-21 abolished the generation of skin lesions in K5.Stat3C mice. Finally, we treated psoriasis patients with STA-21-containing ointment in a nonrandomized study. Psoriatic lesions in six of the eight patients showed improvement after topical STA-21 treatment for 2 weeks. Therefore, we conclude that targeting Stat3 may lead to a therapy for psoriasis.

Topics: Administration, Topical; Animals; Cell Division; Cell Nucleus; Epidermis; Feasibility Studies; Humans; Keratin-10; Keratinocytes; Mice; Mice, Transgenic; Polycyclic Compounds; Protein Precursors; Psoriasis; STAT3 Transcription Factor; Transglutaminases

The mechanisms of action of urea-containing ointments in the treatment of eczema, ichthyosis and psoriasis are only partly known and related to proteolysis and keratinolysis. In this study, we have examined the effects of topical urea on epidermal proliferation and differentiation in 10 patients with psoriasis. Plaque type lesions were treated for 2 weeks with an ointment containing 10% urea, with the vehicle alone, or left untreated. Clinical score, hydration of the stratum corneum, transepidermal water loss (TEWL), and immunohistochemical studies were performed. Epidermal proliferation was assessed using the Ki-S3 proliferation-associated nuclear antigen. For epidermal differentiation antibodies against involucrin and against keratins CK 5, 6, 17 and CK 1, 5, 10, 14 were used. The patients showed a reduction of the clinical score (> 50%), a 2-fold increase in stratum corneum hydration (p < 0.01), and a small decrease in TEWL (N.S.) on the urea- treated compared to the untreated site. Light microscopy studies revealed a 29% reduction in epidermal thickness (p < 0.01); epidermal proliferation was decreased by 51% (p < 0.005). The altered expression of involucrin and of cytokeratins (reduction of CK 5, 1 and 10 and induction of CK 6 and 17) was partially reversed. The ointment base also improved psoriasis, but urea was significantly better than the vehicle (urea: 40% reduction in epidermal proliferation vs. vehicle). In summary, these studies show that urea influences epidermal proliferation and differentiation in psoriasis.

Topics: Administration, Topical; Adolescent; Cell Differentiation; Cell Division; Double-Blind Method; Epidermis; Humans; Immunohistochemistry; Keratins; Ointments; Protein Precursors; Psoriasis; Urea

Oral retinoids have been widely used in psoriasis, but topical forms have been ineffective or irritating.. Our purpose was to determine the clinical and molecular effects of a new topical retinoid, AGN 190168, on psoriasis.. Seven patients with psoriasis were treated for 2 weeks with topical retinoid and 2 weeks with vehicle. Two control subjects with psoriasis were treated for 2 weeks with vehicle alone. Biopsy specimens from normal skin as well as from untreated and treated psoriatic lesions were compared by immunohistochemical analysis. Differentiation and inflammatory markers were studied.. Clinical improvement was seen in all seven patients after 2 weeks of treatment. Improvement was still present, but not significant, after 2 additional weeks of vehicle application. Histologic examination showed a return to a more normal morphology in four of seven biopsy specimens, which correlated with filaggrin expression. There was a diminution in the precocious expression of keratinocyte transglutaminase, keratin 16, and involucrin, as well as a decrease in epidermal growth factor receptor and in the number of cells expressing intercellular adhesion molecule type 1 and HLA-DR.. Clinical and histologic improvements were seen in psoriasis in association with the topical application of AGN 190168 at 2 weeks, including decreased inflammation and restoration of normal epidermal differentiation. Small patient numbers and the possibility that the changes were related to clinical improvement alone and not the topical agent preclude definitive conclusions.

Topics: Administration, Cutaneous; Adult; Antigens, CD; Biopsy; Cell Adhesion Molecules; Double-Blind Method; Epidermis; ErbB Receptors; Female; Filaggrin Proteins; Follow-Up Studies; HLA-DR Antigens; Humans; Immunohistochemistry; Intercellular Adhesion Molecule-1; Intermediate Filament Proteins; Keratinocytes; Keratins; Male; Nicotinic Acids; Pilot Projects; Prospective Studies; Protein Precursors; Psoriasis; Retinoids; Severity of Illness Index; Skin; Transglutaminases

Psoriasis is a skin disorder characterized by epidermal hyperplasia, hyperkeratosis, and inflammation. The treatments currently available on the market only improve patients' quality of life and are associated with undesirable side effects. Thus, research leading to the development of new, effective, and safer therapeutic agents is still relevant.

Topics: Administration, Topical; Adolescent; Adult; Anti-Inflammatory Agents; Antioxidants; Chalcones; Dermatologic Agents; Epidermis; Female; Humans; Inhibitory Concentration 50; Ki-67 Antigen; Male; Membrane Proteins; Methotrexate; Middle Aged; Populus; Protein Precursors; Psoriasis; Quality of Life; Skin; Tissue Engineering; Young Adult

Psoriasis is an inflammatory skin disorder characterized by the hyperproliferation of basal epidermal cells. It is regarded as T-cell mediated, but the role of keratinocytes (KCs) in the disease pathogenesis has reemerged, with genetic studies identifying KC-associated genes. We applied flow cytometry on KCs from lesional and nonlesional epidermis to characterize the phenotype in the germinative compartment in psoriasis, and we observed an overall increase in the stemness markers CD29 (2.4-fold), CD44 (2.9-fold), CD49f (2.8-fold), and p63 (1.4-fold). We found a reduced percentage of cells positive for the early differentiation marker cytokeratin 10 and a greater fraction of CD29

Topics: Biomarkers; Cell Differentiation; Cells, Cultured; Flow Cytometry; Humans; Inflammation; Integrin beta1; Interleukin-17; Interleukin-22; Interleukins; Keratinocytes; Protein Precursors; Psoriasis; Regeneration; Skin; Stem Cells

The mTOR (mechanistic target of rapamycin) inhibitor rapamycin has long been known for its immune suppressive properties, but it has shown limited therapeutic success when given systemically to patients with psoriasis. Recent data have shown that the mTOR pathway is hyperactivated in lesional psoriatic skin, which probably contributes to the disease by interfering with maturation of keratinocytes. This study investigated the effect of topical rapamycin treatment in an imiquimod-induced psoriatic mouse model. The disease was less severe if the mice had received rapamycin treatment. Immunohistological analysis revealed that rapamycin not only prevented the activation of mTOR signalling (P-mTOR and P-S6 levels), but almost normalized the expression of epidermal differentiation markers. In addition, the influx of innate immune cells into the draining lymph nodes was partially reduced by rapamycin treatment. These data emphasize the role of mTOR signalling in the pathogenesis of psoriasis, and support the investigation of topical mTOR inhibition as a novel anti-psoriatic strategy.

Topics: Administration, Topical; Aminoquinolines; Animals; Caspase 14; Dendritic Cells; Disease Models, Animal; Imiquimod; Immunosuppressive Agents; Keratin-10; Keratin-14; Ki-67 Antigen; Langerhans Cells; Lymph Nodes; Macrophages; Membrane Proteins; Mice, Inbred BALB C; Neovascularization, Physiologic; Protein Precursors; Psoriasis; Sirolimus; Skin; TOR Serine-Threonine Kinases

Psoriasin, which is highly expressed in psoriasis, is encoded by a gene located within the epidermal differentiation complex. The aim of this study was to investigate the effect of endogenous psoriasin on disturbed keratinocyte differentiation in psoriasis. Immunohistochemical staining revealed a gradient of psoriasin expression in the psoriatic epidermis with highest expression in the suprabasal, differentiated layers. Induction of keratinocyte differentiation caused concurrent expression of psoriasin and the differentiation marker involucrin. The differentiation-induced psoriasin expression was found to be mediated by the protein kinase C pathway. The downregulation of psoriasin expression by small interfering RNA revealed that psoriasin mediates the expression of involucrin, desmoglein 1, transglutaminase 1 and CD24 in normal differentiation. The lentivirus-mediated overexpression of psoriasin, mimicking the psoriatic milieu, gave rise to an altered regulation of differentiation genes and an expression pattern reminiscent of that in psoriatic epidermis. These findings suggest that psoriasin contributes to the dysregulated differentiation process in the psoriasis epidermis.

Topics: Case-Control Studies; CD24 Antigen; Cell Differentiation; Cells, Cultured; Desmoglein 1; Epidermis; Humans; Keratinocytes; Protein Kinase C; Protein Precursors; Psoriasis; RNA Interference; S100 Calcium Binding Protein A7; S100 Proteins; Signal Transduction; Transfection; Transglutaminases; Up-Regulation

The F1F0-ATP synthase, an enzyme complex, is mainly located on the mitochondrial inner membrane or sometimes cytomembrane to generate or hydrolyze ATP, play a role in cell proliferation. This study focused on the role of F1F0-ATP synthase in keratinocyte differentiation, and its relationship with intracellular and extracellular ATP (InATP and ExATP). The F1F0-ATP synthase β subunit (ATP5B) expression in various skin tissues and confluence-dependent HaCaT differentiation models was detected. ATP5B expression increased with keratinocyte and HaCaT cell differentiation in normal skin, some epidermis hyper-proliferative diseases, squamous cell carcinoma, and the HaCaT cell differentiation model. The impact of InATP and ExATP content on HaCaT differentiation was reflected by the expression of the differentiation marker involucrin. Inhibition of F1F0-ATP synthase blocked HaCaT cell differentiation, which was associated with a decrease of InATP content, but not with changes of ExATP. Our results revealed that F1F0-ATP synthase expression is associated with the process of keratinocyte differentiation which may possibly be related to InATP synthesis.

Topics: Adenosine Triphosphate; Carcinoma, Squamous Cell; Cell Differentiation; Cell Line, Transformed; Dermatitis; Gene Expression Regulation; Humans; Keratinocytes; Keratoacanthoma; Keratosis, Seborrheic; Mitochondria; Mitochondrial Membranes; Mitochondrial Proton-Translocating ATPases; Protein Precursors; Prurigo; Psoriasis; Skin; Skin Neoplasms; Warts

Propylthiouracil (PTU), an anti-thyroid thioureylene, has been shown to be effective in chronic plaque psoriasis. Involucrin is a precursor protein that is upregulated in psoriasis.. This study evaluated the expression of involucrin in the epidermis of skin in psoriatic plaques before and after treatment with PTU.. This was an open-label, prospective study in which 25 psoriasis patients underwent skin biopsies prior to treatment with oral PTU 100 mg three times per day for 12 weeks. Patients were assessed at 2, 6, and 12 weeks. Skin biopsies were repeated at the same sites at 12 weeks. Pre- and post-treatment specimens were subjected to immunohistochemical staining and real-time polymerase chain reaction for involucrin.. Mean ± standard deviation (SD) scores on the Psoriasis Area and Severity Index reduced significantly from 17.86 ± 9.9 at baseline to 4.63 ± 4.1 at week 12 (P < 0.001). Histomorphometric analysis revealed marked decreases in numbers of positively stained cells and intensity of staining. Staining became localized to the upper granular layers after therapy. Immunohistochemical scoring for involucrin reduced from a mean ± SD of 9.00 ± 0.67 at baseline to 3.90 ± 0.88 at week 12 (P < 0.0001).. In psoriasis, there is increased expression of involucrin, which leads to abnormal keratinocyte differentiation and hence to the formation of psoriatic plaques. The therapeutic effect of PTU in psoriasis may be attributable to the downregulation of involucrin. Larger trials should further elucidate the mechanism and therapeutic potential of PTU in psoriasis.

Topics: Adult; Aged; Antithyroid Agents; Down-Regulation; Female; Humans; Male; Middle Aged; Propylthiouracil; Prospective Studies; Protein Precursors; Psoriasis; RNA; Severity of Illness Index; Young Adult

Psoriasis is a chronic inflammatory disorder of skin and joints for which conventional treatments that are effective in clearing the moderate-to-severe disease are limited due to long-term safety issues. This necessitates exploring the usefulness of botanical agents for treating psoriasis. We previously showed that delphinidin, a diet-derived anthocyanidin endowed with antioxidant and anti-inflammatory properties, induces normal epidermal keratinocyte differentiation and suggested its possible usefulness for the treatment of psoriasis [1].. To investigate the effect of delphinidin (0-20 μM; 2-5 days) on psoriatic epidermal keratinocyte differentiation, proliferation and inflammation using a three-dimensional reconstructed human psoriatic skin equivalent (PSE) model.. PSEs and normal skin equivalents (NSEs) established on fibroblast-contracted collagen gels with respective psoriatic and normal keratinocytes and treated with/without delphinidin were analyzed for histology, expression of markers of differentiation, proliferation and inflammation using histomorphometry, immunoblotting, immunochemistry, qPCR and cultured supernatants for cytokine with a Multi-Analyte ELISArray Kit.. Our data show that treatment of PSE with delphinidin induced (1) cornification without affecting apoptosis and (2) the mRNA and protein expression of markers of differentiation (caspase-14, filaggrin, loricrin, involucrin). It also decreased the expression of markers of proliferation (Ki67 and proliferating cell nuclear antigen) and inflammation (inducible nitric oxide synthase and antimicrobial peptides S100A7-psoriasin and S100A15-koebnerisin, which are often induced in psoriatic skin). ELISArray showed increased release of psoriasis-associated keratinocyte-derived proinflammatory cytokines in supernatants of the PSE cultures, and this increase was significantly suppressed by delphinidin.. These observations provide a rationale for developing delphinidin for the management of psoriasis.

Topics: Anthocyanins; Anti-Inflammatory Agents; Caspases; Cell Differentiation; Cells, Cultured; Cytokines; Filaggrin Proteins; Humans; Keratinocytes; Membrane Proteins; Models, Biological; Protein Precursors; Psoriasis; RNA, Messenger; S100 Calcium Binding Protein A7; S100 Proteins; Skin

Psoriasis is a complex inflammatory skin disease that presents a wide variety of clinical manifestations. Human β defensin-2 (hBD-2) is highly up-regulated in psoriatic lesions and has been defined as a biomarker for disease activity. We explored the potential benefits of targeting hBD-2 by topical application of DEFB4-siRNA-containing SECosomes in a bioengineered skin-humanized mouse model for psoriasis. A significant improvement in the psoriatic phenotype was observed by histological examination, with a normalization of the skin architecture and a reduction in the number and size of blood vessels in the dermal compartment. Treatment leads to the recovery of transglutaminase activity, filaggrin expression and stratum corneum appearance to the levels similar to those found in normal regenerated human skin. The availability of a reliable skin-humanized mouse model for psoriasis in conjunction with the use of the SECosome technology may provide a valuable preclinical tool for identifying potential therapeutic targets for this disease.

Topics: Administration, Cutaneous; Animals; beta-Defensins; Bioengineering; Cell Differentiation; Cell Proliferation; Dermis; Disease Models, Animal; Elafin; Epidermis; Filaggrin Proteins; Gene Expression; Gene Silencing; Humans; Intermediate Filament Proteins; Keratin-1; Keratin-17; Ki-67 Antigen; Leukocyte L1 Antigen Complex; Liposomes; Mice; Molecular Targeted Therapy; Nanoparticles; Protein Precursors; Psoriasis; RNA, Small Interfering; S100 Calcium Binding Protein A7; S100 Proteins

Epidermal fatty acid-binding protein (E-FABP) is a lipid carrier, originally discovered in human epidermis. We show that E-FABP is almost exclusively expressed in postmitotic (PM) keratinocytes, corresponding to its localization in the highest suprabasal layers, while it is barely expressed in keratinocyte stem cells (KSC) and transit amplifying (TA) keratinocytes. Transfection of normal human keratinocytes with recombinant (r) E-FABP induces overexpression of K10 and involucrin. On the other hand, E-FABP inhibition by siRNA downregulates K10 and involucrin expression in normal keratinocytes through NF-κB and JNK signalling pathways. E-FABP is highly expressed in psoriatic epidermis, and it is mainly localized in stratum spinosum. Psoriatic PM keratinocytes overexpress E-FABP as compared to the same population in normal epidermis. E-FABP inhibition in psoriatic keratinocytes markedly reduces differentiation, while it upregulates psoriatic markers such as survivin and K16. However, under high-calcium conditions, E-FABP silencing downregulates K10 and involucrin, while survivin and K16 expression is completely abolished. These data strongly indicate that E-FABP plays an important role in keratinocyte differentiation. Moreover, E-FABP modulates differentiation in psoriatic keratinocytes.

Topics: Cell Differentiation; Cells, Cultured; Fatty Acid-Binding Proteins; Humans; Keratin-10; Keratinocytes; Protein Precursors; Psoriasis; Recombinant Proteins; RNA, Small Interfering

The role of transforming growth factor-β1 (TGFβ1) and Smad signalling has not been established in psoriasis treatment. We aimed to investigate the effect of combined treatment with salt water soaks and ultraviolet radiation on the expression of TGFβ1/Smad signalling proteins in a psoriatic model. We studied mRNA expression (real-time RT-PCR) of TGFβ1, TGFβ receptor type I (TGFβRI), Smad2, Smad3, Smad4, Smad7, minichromosome maintenance protein 7, and involucrin in normal as well as psoriatic epidermis models (PEM) which were treated for three consecutive days with differently concentrated salt water solutions [(3% NaCl; 30% NaCl, 30% Dead Sea salt water (DSSW)] and subsequent narrowband ultraviolet B (NB-UVB). In PEM, TGFβ1 and Smad3 was significantly increased as compared to normal epidermis models. By contrast, TGFβRI mRNA was significantly decreased in PEM. Significant increase of mRNA levels of TGFβ1, TGFβRI, Smad2 and Smad3 was predominantly observed in non-irradiated and irradiated PEM pre-treated with 30% NaCl and/or DSSW which was paralleled by increase of involucrin mRNA. In PEM pre-treated with DSSW, TGFβRI, Smad2, Smad3, Smad4, and Smad7 mRNA was significantly higher in irradiated PEM when compared to non-irradiated samples. It has been shown that TGFβ1/Smad signalling is altered in a psoriatic model and may play a role in the mode of action of salt water soaks and NB-UVB phototherapy of psoriasis.

Topics: Cell Line; Epidermis; Humans; Keratinocytes; Minichromosome Maintenance Complex Component 7; Protein Precursors; Psoriasis; Receptors, Transforming Growth Factor beta; RNA, Messenger; Signal Transduction; Smad Proteins; Smad2 Protein; Smad3 Protein; Smad4 Protein; Smad7 Protein; Sodium Chloride; Transforming Growth Factor beta1; Ultraviolet Therapy

Toll-like receptor 7 (TLR7) is an important member in pattern recognition receptors families. TLR7 signal pathway is involved in the physiological process in many type cells, but the impact of TRL7 on differentiation in the human keratinocytes is still unknown. In this study, we investigated the expression of TLR7 in keratinocytes, and the effect of TLR7 agonist gardiquimod on the expression of calcium (Ca(2+))-induced keratinocytes differentiation markers in HaCaT cells. Immunohistochemistry and western-blotting analysis showed that TLR7 is expressed in basal keratinocytes of normal skin and in the human keratinocyte cell line HaCaT, but not expressed in the keratinocytes of psoriasis lesions. Pretreatment with gardiquimod could down-regulate Ca(2+)-induced differentiation marker expression and activate Raf-MEK-ERK and PI3K-AKT signal pathways in HaCaT cells. However, specific inhibitors studies showed that the down-regulation of the differentiation markers expression by gardiquimod was not dependent on the activation of these two pathways. TLR7 may play an important role in the pathogenesis of psoriasis through regulating the differentiation of the keratinocytes, and will give a new insight into the psoriasis.

Topics: Aminoquinolines; Antigens, Differentiation; Calcium; Cell Line; Gene Expression Regulation; Humans; Imidazoles; Keratin-1; Keratinocytes; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Protein Precursors; Proto-Oncogene Proteins c-akt; Psoriasis; Signal Transduction; Toll-Like Receptor 7; Toll-Like Receptors

Psoriasis, a common inflammatory skin disease, is characterized by epidermal hyperplasia, abnormal differentiation, angiogenesis, immune activation, and inflammation. Involucrin is an early terminal differentiation marker of epidermal keratinocytes. In this study, we determined the immunolocalization of involucrin in psoriatic lesions and normal skin of individuals without psoriasis by means of immunofluorescence (IF) assay. Furthermore, the regulation of involucrin by interleukin (IL)-13, IL-17A, endothelin (ET)-1, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ was investigated by Western blot. Extracellular regulate protein kinases 1/2 (ERK1/2) and glycogen syntheses kinase-3β (GSK-3β) inhibitors were also included to define the roles of these signals in the production of involucrin in both psoriatic and normal keratinocytes. In psoriatic lesional skin, involucrin was detected in the stratum spinosum, but not in the basal or the cornified layer. In normal skin, involucrin was restricted to the granular layer and the upper stratum spinosum. IL-13, IL-17A, ET-1, TNF-α, and IFN-γ up-regulate expression of involucrin in both psoriatic and normal keratinocytes. However, this effect was abolished by ERK1/2 and GSK-3β inhibitors. In conclusion, involucrin is up-regulated in psoriatic keratinocytes. IL-13, IL-17A, ET-1, TNF-α, and IFN-γ could increase involucrin protein levels in psoriatic and normal keratinocytes. The ERK1/2 and GSK-3β signaling pathways may play positive roles in regulating epidermal differentiation as observed in psoriasis.

Topics: Adult; Aged; Cell Differentiation; Endothelin-1; Epidermis; Extracellular Signal-Regulated MAP Kinases; Female; Gene Expression Regulation; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Interferon-gamma; Interleukin-13; Interleukin-17; Keratinocytes; Male; Middle Aged; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Protein Kinase Inhibitors; Protein Precursors; Psoriasis; Tumor Necrosis Factor-alpha; Young Adult

Tumor Necrosis Factor-α (TNF-α) plays a pivotal role in psoriasis, an immuno-mediated and genetic skin disease. Anti-TNF-α inhibitors, such as etanercept, are widely used in clinical practice. By immunofluorescence, we investigated the expression of junctional transmembrane proteins in desmosomes (desmocollin-1, Dsc1; desmoglein-1, Dsg1), adherens junctions (E-cadherin), tight junctions (occludin), biomarkers of keratinocyte differentiation (keratin-10, K10; keratin-14, K14; keratin-16, K16; involucrin), epithelial proliferation and apoptosis in psoriatic skin before/after etanercept treatment (n = 5) and in control skin samples (n = 5). Occludin, K14, K16 and involucrin expressions were altered in psoriatic epidermis, while Dsc1, Dsg1, E-cadherin and K10 localisations were comparable to controls. Etanercept promoted the restoration of the physiological condition as suggested by a more differentiated keratinocyte phenotype and a reduced epidermal proliferation rate.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Cadherins; Cell Differentiation; Cell Proliferation; Desmocollins; Desmoglein 1; Desmosomes; Etanercept; Female; Humans; Immunoglobulin G; Keratin-10; Keratin-14; Keratin-16; Keratinocytes; Occludin; Phenotype; Protein Precursors; Psoriasis; Receptors, Tumor Necrosis Factor; Tight Junctions; Tumor Necrosis Factor-alpha

Fatty acid-binding proteins (FABPs) are postulated to serve as lipid shuttles that solubilize hydrophobic fatty acids and deliver them to appropriate intracellular sites. Epidermal FABP (E-FABP/FABP5) is predominantly expressed in keratinocytes and is overexpressed in the actively proliferating tissue characteristic of psoriasis and wound healing. In this study, we found decreased expression of the differentiation-specific proteins keratin 1, involucrin, and loricrin in E-FABP(-/-) keratinocytes relative to E-FABP(+/+) keratinocytes. We also determined that incorporation of linoleic acid was significantly reduced in E-FABP(-/-) keratinocytes. Although linoleic acid did not directly affect keratinocyte differentiation, keratin 1 expression was induced by the linoleic acid derivative 13(S)-hydroxyoctadecadienoic acid (13(S)-HODE), and this induction was concomitant with increased NF-κB activity. In E-FABP(-/-) keratinocytes, the expression of 13(S)-HODE and the subsequent induction of NF-κB activity was lower than in wild-type keratinocytes. The reduction of linoleic acid in E-FABP(-/-) keratinocytes led to decreased cellular 13(S)-HODE content, resulting in decreased keratin 1 expression through downregulation of NF-κB activity. The regulation of fatty acid metabolism by E-FABP during keratinocyte differentiation suggests that E-FABP may have a role in the pathogenesis of psoriasis.

Topics: Animals; Cell Differentiation; Cells, Cultured; Disease Models, Animal; Epidermis; Fatty Acid-Binding Proteins; Fatty Acids; Keratin-1; Keratinocytes; Linoleic Acid; Linoleic Acids; Membrane Proteins; Mice; Mice, Knockout; Neoplasm Proteins; NF-kappa B; Protein Precursors; Psoriasis; Signal Transduction

alpha2beta1 integrins are normally confined to the proliferating basal layers of the epidermis. However, during wound healing and in psoriasis, these integrins are expressed on keratinocytes in suprabasal layers correlating with a less differentiated phenotype. Transgenic mice expressing alpha2beta1 integrins under the involucrine promoter have previously been demonstrated, to various degrees, spontaneously develop a skin disorder resembling psoriasis. Herein, we show that a mild epidermal wounding induces a uniform acanthosis together with an influx of immune cells. The disease initiates as a normal wound healing process and is completely restored in wildtype mice by day 14. However, in the integrin transgenic mice a chronic inflammation develops, a process that can be compared to the Koebner phenomenon in psoriatic patients. In this study, we have followed the integrin transgenic mice for five weeks, where substantial keratinocyte hyper-proliferation, inflammatory infiltration and high cytokine levels within the skin can still be observed. In addition, draining lymph nodes were dramatically increased in size and contained highly activated T cells, as well as APCs secreting large amounts of pro-inflammatory cytokines. Furthermore, the systemic immune response was affected with increased spleen size, elevated cytokine levels in the serum and altered lymphocyte trafficking patterns, very much resembling what is seen in psoriasis patients. Finally, CD4(+) T cell depletion was not able to affect the onset or progression of skin inflammation. This suggests that altered keratinocyte differentiation and proliferation can drive a skin inflammation and cause chronic immune cell activation both at a local and systemic level.

Topics: Animals; Cell Differentiation; Cell Movement; Cell Proliferation; Cytokines; Humans; Inflammation; Integrin alpha2beta1; Keratinocytes; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Mice, Transgenic; Protein Precursors; Psoriasis; Skin; T-Lymphocytes; Wound Healing

Psoriasis is a chronic skin disease characterized by a thickening and disorganization of the skin's protective barrier.. This study aims to develop and characterize a novel in vitro psoriatic human skin model produced by tissue engineering.. The self-assembly method, a tissue engineering approach based on the capacity of mesenchymal cells, such as fibroblasts, to create their own extracellular matrix in vitro, was used to create our substitutes. Manipulatable sheets of fibroblasts were superimposed creating a new dermis upon which keratinocytes are seeded, leading to a complete bilayered skin substitute. The characterization of the psoriatic substitutes was performed by macroscopic, histological and immunohistochemical analyses and contrasted to those constructed from healthy cells.. Macroscopically, the psoriatic substitutes were more white and thicker than the healthy substitutes. The histological analysis of psoriatic substitutes stained with Masson's trichrome revealed a characteristic thickening of the epidermal layer seen in psoriatic skin in vivo. Immunohistochemical analysis of the psoriatic substitutes showed, among other things, an overexpression of involucrin and an underexpression of filaggrin and loricrin.. These data suggest that the macroscopic, histological and immunohistochemical characteristics of psoriasis are partially retained in the substitutes, thus providing a good model to investigate the mechanisms of abnormal keratinocyte growth and to study cell-cell interactions.

Topics: Adult; Aged; Biopsy; Cell Communication; Cell Proliferation; Extracellular Matrix; Female; Fibroblasts; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Keratinocytes; Male; Membrane Proteins; Middle Aged; Models, Biological; Protein Precursors; Psoriasis; Skin; Tissue Engineering

Indigo naturalis has shown efficacy in treating psoriasis in our previous clinical studies.. To investigate the potential effect of indigo naturalis on regulating keratinocyte proliferation and differentiation.. Skin samples from six patients were analyzed for proliferating cell nuclear antigen (PCNA) and involucrin expression by immunohistochemical staining. In addition, indigo naturalis extracts from 10 to 500 microg/ml were added to cultured keratinocytes and cell viability determined. Real-time RT-PCR, Western blotting analysis and indirect immunofluorescent labeling were used to investigate the messenger (m)RNA and protein expressions of PCNA and involucrin. Finally, high-performance liquid chromatography (HPLC) was used to identify major components of indigo naturalis and their in vitro effects compared.. Immunohistochemical results demonstrated decreased PCNA and increased involucrin in psoriatic lesions after indigo naturalis treatment. Cultured keratinocytes decreased after indigo naturalis treatment, while G(0)/G(1) arrest was observed to dose-dependently increase. Staining revealed decreased PCNA-stained nuclei and increased cytosolic involucrin in treated keratinocytes. Decreased PCNA and increased involucrin at both the mRNA and protein levels were confirmed. Both major components, indirubin and indigo, could cause G(0)/G(1) phase arrest; however, only indirubin modulated the expressions of PCNA and involucrin similar to indigo naturalis.. Together, these findings indicate that the anti-psoriatic effects of indigo naturalis are mediated, at least in part, by modulating the proliferation and differentiation of keratinocytes, with indirubin as the major active component.

Topics: Cell Cycle; Cell Survival; Cells, Cultured; Dermatologic Agents; Down-Regulation; Gene Expression; Humans; Indigo Carmine; Indigofera; Indoles; Keratinocytes; Phytotherapy; Plant Extracts; Proliferating Cell Nuclear Antigen; Protein Precursors; Psoriasis

Chronic inflammation of psoriatic lesions may be due to an exaggerated innate immune response. Toll-like receptors (TLRs) are expressed by keratinocytes in psoriasis. Antikeratin 16 autoantibodies (AK16 autoAbs) are increased in serum from patients with psoriasis. Whether the elevated AK16 autoAbs play a role in psoriasis by exaggerating innate immune response is still unknown.. To prove that AK16 autoAbs are involved in psoriasis, by exaggerating the innate immune response of keratinocytes.. Keratinocytes were incubated with mouse antikeratin 16 monoclonal antibodies (AK16 mAbs) for a given length of time. Levels of TLR2, TLR4, involucrin and nascent polypeptide-associated complex (NACA) mRNA were measured by quantitative RT-PCR. Levels of TLR2, TLR4, involucrin, NF-kappaB and actin-related protein 2 (ARP2) protein were measured by flow cytometry or Western blot. Effects of the mAbs on keratinocytes were studied using DNA synthesis and cell cycle analysis.. TLR2 mRNA increased 1.73-, 1.60- and 2.52-fold at 6, 24 and 36 h after incubation, respectively. TLR4 mRNA increased 3.62- and 2.21-fold after 12 and 36 h. Involucrin mRNA increased 2.33- and 2.0-fold after 12 and 36 h. NACA mRNA increased 5.93-, 3.35- and 3.54-fold after 12, 24 and 36 h. TLR2 protein increased 1.73-fold on the cell membrane and 2.22-fold on membrane plus intracytoplasm. NF-kappaB increased 2.64-fold after 6 h. Involucrin protein increased 4.5-fold, whereas Arp2 protein decreased 1.82-fold, after 36 h. The mAbs had an inhibitory effect on cultured keratinocytes.. AK16 autoAbs may be involved in the chronic inflammation of psoriasis lesions by promoting TLR expression.

Topics: Actin-Related Protein 2; Animals; Antibodies, Monoclonal; Autoantibodies; Base Sequence; Cell Cycle; Cells, Cultured; DNA Primers; Humans; Immunity, Innate; Keratin-16; Keratinocytes; Mice; Molecular Chaperones; NF-kappa B; Protein Precursors; Psoriasis; RNA, Messenger; Toll-Like Receptor 2; Toll-Like Receptor 4

Psoriasis is recognized as a chronic inflammatory disease characterized by epidermal hyperproliferation. To identify psoriasis-related genes, we compared the mRNA populations of normal and psoriatic skin. We identified one gene, designated as cornifelin, which showed increased expression in psoriatic skin. Human cornifelin contains 112 amino acids and is expressed in the uterus, cervix, and skin. In situ hybridization analysis demonstrated the presence of human cornifelin in the granular cell layer of the epidermis. To investigate the function of cornifelin, we established a transgenic mouse line overexpressing human cornifelin. Using these mice, we have shown that cornifelin is directly or indirectly cross-linked to at least two other cornified envelope proteins, loricrin and involucrin, in vivo. Overexpression of human cornifelin correlated with decreased loricrin expression and increased involucrin expression in the transgenic mouse. However, abnormality of epidermal differentiation was not observed in the transgenic mouse.

Topics: Amino Acid Sequence; Animals; Base Sequence; Gene Expression; Humans; Immunohistochemistry; In Situ Hybridization; Keratins; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Molecular Sequence Data; Protein Precursors; Psoriasis; Recombinant Proteins; RNA, Messenger; Sequence Homology, Amino Acid; Skin; Tissue Distribution

We have previously established a non-invasive method to evaluate the maturity of cornified envelopes (CEs), and have reported the appearance of immature CEs in the stratum corneum (SC) with poor barrier function, such as the SC of the face. The purpose of the present study was to evaluate CEs in inflammatory skin disorders, and to clarify the relationship between the appearance of the immature CEs and parakeratosis, which is often used as a marker for defective keratinization in inflammatory skin disorders. Cornified envelopes in the outermost SC of involved areas of psoriasis vulgaris (PV) and atopic dermatitis (AD) were strikingly heterogeneous, and consisted of immature CEs stained with anti-involucrin and mature CEs stained with Nile red, whereas CEs of the uninvolved areas were relatively homogeneous, exhibiting mature phenotype. The ratio of immature CEs was significantly higher in the involved areas of PV and AD than that in the corresponding uninvolved areas, suggesting that defective CE maturation may, at least in part, account for the inflammatory disorders. Simultaneous evaluation of CE maturity and parakeratosis was carried out by a combination of involucrin immunostaining and nuclear staining of detergent-dissociated corneocytes. In the involved area of PV, four types of corneocytes in regard to the combination of involucrin staining and nuclear remnant were observed, while both immature CEs and parakeratosis were more often detected in the involved areas of PV than in the uninvolved areas or the upper arm of healthy subjects as a normal control. Thus, corneocytes with involucrin-positive immature CEs were not always associated with parakeratosis at the cellular level. In the involved areas of PV, the ratio of immature CEs and that of parakeratosis were heterogeneous, depending on the cases, and no correlation between the ratios was observed. Inter-individual and intraindividual variations in CE maturity were also suggested by the heterogeneous localization of involucrin in the psoriatic epidermis as examined by immunohistochemistry. In addition, in the face of healthy subjects, four types of corneocytes were similarly detected, and the ratio of immature CEs was significantly higher than that of parakeratosis. These results obviously suggest that the maturation of CEs and disappearance of nuclei are differentially regulated in the epidermis.

Topics: Cell Nucleus; Dermatitis; Epidermis; Humans; Parakeratosis; Protein Precursors; Psoriasis

Elafin is a serine proteinase inhibitor highly expressed in psoriatic epidermal keratinocytes, but expressed scarcely, if at all, in normal skin. In addition to the proteinase inhibiting domain, elafin contains multiple transglutaminase substrate domains and has been identified as a constituent of the epidermal cornified cell envelope. It also contains a signal peptide sequence, and previous immunoelectron microscopy studies detected elafin in lamellar granules and also in the intercellular spaces. It has not been explained, however, how and when elafin molecules stored in the granules are cross-linked into the cell envelope. In order to elucidate this issue, we performed pre-embedding and postembedding immunoelectron microscopy of elafin and involucrin, another cell envelope constituent, using psoriatic epidermis. Postembedding double immunoelectron microscopy revealed that elafin was within the secretory (lamellar) granules and released into the intercellular spaces when the cell envelope was not formed. In the cells with involucrin-positive cell envelope, elafin immunolabels were localized diffusely within the cells and also along the cell envelope. Pre-embedding immunoelectron microscopy of purified cell envelope from psoriatic scale samples detected involucrin and elafin colocalizing on the cytoplasmic side of the cell envelope. These findings strongly suggest that elafin-containing granules are disintegrated upon the initiation of cell envelope formation, and that elafin is cross-linked on to the involucrin-positive cell envelope from the inside of keratinocytes. It seems that psoriatic keratinocytes utilize elafin as a major component of the cell envelope, consistent with the previously proposed "precursor availability hypothesis".

Topics: Cross-Linking Reagents; Cytoplasm; Epidermis; Golgi Apparatus; Humans; Keratinocytes; Microscopy, Immunoelectron; Protein Precursors; Proteinase Inhibitory Proteins, Secretory; Proteins; Psoriasis; Secretory Vesicles

In normal epidermis, beta1 integrin expression is confined to the basal layer, whereas in hyperproliferative epidermis, integrins are also expressed in the suprabasal layers. Transgenic mice in which integrins are expressed suprabasally via the involucrin promoter have a sporadic psoriatic phenotype; however, the mechanism by which integrins contribute to the pathogenesis of psoriasis is unknown. We observed activation of mitogen-activated protein kinase (MAPK) in basal and suprabasal keratinocytes of human and transgenic mouse psoriatic lesions and healing mouse skin wounds, correlating in each case with suprabasal integrin expression. Phenotypically normal human and transgenic mouse epidermis did not contain activated MAPK. Transgene-positive keratinocytes produced more IL-1alpha than controls did, and keratinocyte MAPK could be activated by ligation of suprabasal integrins or treatment with IL-1alpha. Constitutive activation of MAPK increased the growth rate of human keratinocytes and delayed the onset of terminal differentiation, recreating many of the histological features of psoriatic epidermis. We propose that activation of MAPK by integrins, either directly or through increased IL-1alpha production, is responsible for epidermal hyperproliferation in psoriasis and wound healing, and that the sporadic phenotype of the transgenic mice may reflect the complex mechanisms by which IL-1 release and responsiveness are controlled in skin.

Topics: Animals; Antigens, Differentiation; Cell Differentiation; Cell Division; Cell Line, Transformed; Cells, Cultured; Enzyme Activation; Epidermis; Genes, Synthetic; Humans; Hyperplasia; Integrin beta1; Integrins; Interleukin-1; Keratinocytes; MAP Kinase Signaling System; Mice; Mice, Transgenic; Microscopy; Microscopy, Fluorescence; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Phenotype; Promoter Regions, Genetic; Protein Precursors; Psoriasis; Receptors, Collagen; Recombinant Fusion Proteins; Transfection; Wound Healing

Twenty-nine psoriatics were examined using a model with clinical, physiological and pathological assessment parameters. The three parts in this assessment model include: (1) clinical assessment: psoriasis area and severity index (PASI); (2) assessment of skin physiology and microcirculation: water content of stratum corneum, water-holding capacity of stratum corneum, transepidermal water loss, intravital dynamic videocapillaroscopy-measuring the capillary diameters and blood cell velocity in proximal nailfold of ring finger, and fluorescence angiography-measuring transcapillary Na-fluorescein(NAF) diffusion; and (3) immunohistochemistry examination: markers of proliferation (Ki67Ag), differentiation (involucrin), and inflammation (neutrophil elastase, intercellular adhesion molecule-1(ICAM-1), endothelial leukocyte adhesion molecule-1(ELAM-1)). Our results showed both the transcapillary diffusion of NAF and the expression of cell markers-dermal neutrophil elastase, epidermal ELAM-1 and Ki67Ag--correlated significantly to PASI scores (P < 0.05, linear regression). According to our results, the increased capillary permeability and inflammation markers, and enhanced expression of Ki67Ag correlated very well with PASI score. These markers could serve as alternative methods for assessment of the clinical severity of psoriatic patients.

Topics: Adolescent; Adult; Aged; Biomarkers; E-Selectin; Female; Humans; Intercellular Adhesion Molecule-1; Ki-67 Antigen; Leukocyte Elastase; Male; Middle Aged; Protein Precursors; Psoriasis; Skin

Several authors have questioned the existence of unilateral (linear) psoriasis. These authors have suggested that the condition is actually an inflammatory linear verrucous epidermal nevus, or the result of an isomorphic effect on a pre-existing epidermal nevus. We report the case of a 25-year-old man, with no relevant personal or family history, who presented with a number of pruritic, punctiform erythematosquamous lesions that were linearly distributed over the left side of the body. Clinical examination and results of histopathologic and histochemical studies indicated unilateral psoriasis. Our findings confirm that involucrin immunohistochemistry can be a useful diagnostic tool in cases of this type. Treatment with keratolytics and topical calcipotriol led to a significant, but only temporary, improvement.

Topics: Adult; Biopsy, Needle; Diagnosis, Differential; Epidermis; Humans; Immunohistochemistry; Male; Nevus, Intradermal; Protein Precursors; Psoriasis; Skin Neoplasms

The biologically active vitamin D analog calcipotriol is effective and safe in the topical treatment of psoriasis, but its exact mechanism of action is unknown.. We investigated expression of 1,25-dihydroxyvitamin D3 receptors, markers for inflammation (CD1a, CD4, CD8, CD11b, CD15; NAP-1/interleukin-8; 55 kd tumor necrosis factor-receptor; intercellular adhesion molecule-1; HLA-DR), proliferation (proliferating cell nuclear antigen, Ki-67), and differentiation (transglutaminase K; involucrin; cytokeratin 16) in psoriatic skin during topical calcipotriol treatment.. For immunohistochemical staining we used the labeled avidin-biotin technique on cryostat-cut sections.. We found a significant increase of 1,25-dihydroxyvitamin D3 receptor expression in epidermal basal keratinocytes of lesional psoriatic skin during calcipotriol treatment. In all patients analyzed, effects on proliferation and differentiation of epidermal keratinocytes were stronger than effects on dermal inflammation. Effects on inflammation were more pronounced in the epidermal than in the dermal compartment.. Our findings indicate that analogs of 1,25-dihydroxyvitamin D3 upregulate their corresponding receptor in human keratinocytes in vivo. This mechanism may be important in the therapeutic efficacy of vitamin D analogs in psoriasis. The differential therapeutic effects in the epidermal and dermal skin compartments may be due to a reduced bioavailability of calcipotriol in the dermal compartment.

Topics: Administration, Cutaneous; Antigens, CD; Antigens, CD1; Biological Availability; Calcitriol; CD11 Antigens; CD4 Antigens; CD8 Antigens; Cell Differentiation; Cell Division; Dermatologic Agents; Epidermis; Gene Expression Regulation; HLA-DR Antigens; Humans; Immunoenzyme Techniques; Immunohistochemistry; Intercellular Adhesion Molecule-1; Interleukin-8; Keratinocytes; Keratins; Lewis X Antigen; Male; Proliferating Cell Nuclear Antigen; Protein Precursors; Psoriasis; Receptors, Calcitriol; Receptors, Interleukin; Receptors, Interleukin-8A; Receptors, Tumor Necrosis Factor; Skin; Transglutaminases; Tumor Necrosis Factor-alpha; Up-Regulation

Proteinase activity is increased in psoriatic epidermis. To elucidate the involvement of enzymes in psoriatic epidermis, the expression of cathepsins, L, B and D was investigated by Western blotting and immunohistological studies. Normal epidermis contained abundant inactive precursors (39 kDa) of cathepsins L and B and an inactive intermediate form (45 kDa) of cathepsin D. Cathepsin L in psoriasis was processed to a variable extent from the precursor to a single-chain form (30 kDa) and a mixture of single- and heavy-chain (25 kDa) forms of the active mature enzyme, corresponding to the immunohistological staining patterns 'diffuse dense', 'small granular', and unevenly distributed 'condensed granular'. Cathepsin B showed a mixture of precursor form (39 kDa) and single-chain (30 kDa) forms and was expressed as a 'diffuse dense' staining pattern in the mid-spinous layer and as a 'condensed' pattern in the upper spinous and granular layers. Cathepsin D was processed to the heavy-chain (31 kDa) form of activated mature enzyme with small granular staining and a mixture of heavy-chain and degraded protein (28 kDa) with larger and more condensed granular staining. The distribution patterns of 'small granular' cathepsin L, and of cathepsins B and D expression in suprabasal keratinocytes were very similar to that of involucrin. After complete clinical resolution of psoriasis by 8-methoxypsoralen plus UVA treatment, the expression of the three cathepsins was normalized. These results suggest that cathepsins L, B and D in forms activated to a variable extent may be involved in the pathology of psoriasis.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Case-Control Studies; Cathepsin B; Cathepsin D; Cathepsin L; Cathepsins; Child; Cysteine Endopeptidases; Endopeptidases; Enzyme Precursors; Epidermis; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Middle Aged; Protein Precursors; Psoriasis; PUVA Therapy

The peripheral changes in the uninvolved skin adjacent to the extending psoriatic lesions may represent early events. The sequence of these events remains controversial. In the present study we evaluated epidermal and dermal aspects of the margin of the progressive psoriatic plaque, the distant uninvolved skin and normal healthy skin, using immunohistochemistry with markers for keratinization, proliferation and connective tissue: filaggrin, involucrin, Ki-67 and tenascin. The results showed that: (i) processes in distant uninvolved skin were comparable with the observations in normal skin; (ii) in the margin zone of the spreading psoriatic lesion, following the increased appearance of tenascin, the transition into parakeratosis, abnormal expression of filaggrin, involucrin and recruitment of cycling epidermal cells, happened simultaneously. The simultaneous normalization of these epidermal processes might be a consequence of a signal which is simultaneously transduced to the basal and suprabasal cell layers of the epidermis. Based on the present results and earlier findings, we would like to propose a triple stage model for the development of the psoriatic lesion: Stage 1, involvement of the stroma; stage II, inflammatory infiltrate formation and penetration into the upper layers of the epidermis, with suprabasal expression of keratin 16; stage III, recruitment of cycling epidermal cells and abnormal terminal differentiation. Further studies are required on the regulation of tenascin expression, focusing on factors derived from the stroma affecting both recruitment of cycling epidermal cells, involucrin and filaggrin expression. An intermediate step in the dermo-epithelial interrelation is the inflammatory infiltrate, penetrating into the most superficial zone of the epidermis, and the suprabasal expression of keratin 16.

Topics: Adult; Aged; Biopsy; Cell Division; Epidermal Cells; Epidermis; Female; Filaggrin Proteins; Gene Expression Regulation; Humans; Immunohistochemistry; Intermediate Filament Proteins; Keratins; Ki-67 Antigen; Male; Middle Aged; Protein Precursors; Psoriasis; Skin; Tenascin

The potent calciotropic hormone calcitriol (1,25-dihydroxyvitamin D3, 1,25(OH)2D3) has been shown to be very effective and safe in the topical treatment of psoriasis. In vitro, 1,25(OH)2D3 inhibits proliferation and stimulates differentiation of human keratinocytes. Increasing evidence suggests an immunoregulatory function of this potent steroid hormone. To further characterize the biological effects of topical calcitriol treatment in psoriasis, we have analyzed immunohistochemically the expression of markers for epidermal proliferation (proliferating cell nuclear antigen=PCNA) and differentiation (transglutaminase K, involucrin, cytokeratin 16), as well as inflammation (CD1a, 55 kDa TNF-receptor, NAP-1/IL-8) in calcitriol-treated psoriatic skin in situ. Our findings strongly support the hypothesis that calcitriol modulates keratinocyte proliferation/differentiation as well as inflammation in human skin in vivo. The immunoreactivity of markers for epidermal proliferation and differentiation, as well as of CD1a and NAP-1/IL-8, changed after 8 weeks of calcitriol treatment almost completely to the pattern characteristic for non-lesional psoriatic skin, while a large number of 55 kDa TNF-receptor positive cells could be found in the dermal compartment.

Topics: Administration, Topical; Antigens, CD1; Calcitriol; Cell Differentiation; Cell Division; Humans; Immunohistochemistry; Interleukin-8; Keratinocytes; Keratins; Proliferating Cell Nuclear Antigen; Protein Precursors; Psoriasis; Receptors, Tumor Necrosis Factor; Skin; Transglutaminases

Considerable indirect evidence suggests that T lymphocytes have a role in the pathogenesis of psoriasis. The goal of this study was to directly test the ability of T cells to maintain psoriasis pathology. Psoriatic skin was transplanted onto SCID mice, which were then injected with autologous T cells. T cells were cultured from either psoriatic skin lesions or peripheral blood and injected intradermally or intravenously. Control SCID mice transplanted with psoriasis grafts were not injected with T cells. After 10 wk, control psoriatic skin grafts not injected with T cells lost many of the features of psoriasis. Injection of peripheral blood T cells was not able to maintain these psoriatic features. In contrast, the injection of T cells derived from psoriatic skin was able to maintain the psoriatic phenotype. Psoriatic features that were maintained included epidermal thickness and labeling index and expression of HLA-DR, involucrin, and ICAM-1, as well as loss of expression of filaggrin. Injection of skin infiltrating T cells into skin of normal donors on SCID mice did not induce changes of psoriasis. The ability of T cells from lesional skin, but not peripheral blood, to maintain psoriasis suggests that psoriasis is mediated by an autoantigen reactive T cell, which is present at a higher frequency in the psoriatic lesion.

Topics: Adoptive Transfer; Animals; Cell Transplantation; Disease Models, Animal; Filaggrin Proteins; HLA-DR Antigens; Humans; Intercellular Adhesion Molecule-1; Keratinocytes; Mice; Phenotype; Protein Precursors; Psoriasis; Skin Transplantation; Spleen; T-Lymphocytes; Transplantation, Heterologous

In normal skin, proliferation and differentiation are tightly coupled in order to maintain normal architecture in a continually renewing tissue. The temporal and spatial relationships between these two processes in normal, psoriatic, pre-neoplastic and neoplastic skin were investigated by a double immunolabelling technique with Ki67 as a marker of proliferation and involucrin as a marker of terminal differentiation. In normal skin, expression of the two antigens was strictly spatially segregated. In the abnormal, the proportions of cells expressing the antigens were increased with some loss of the spatial segregation, while small numbers of cells showed dual expression suggesting loss of the normal control between proliferation and differentiation. However, the quantitative ratio of proliferation to differentiation in psoriatic and pre-neoplastic skin was similar to the normal; transition to an invasive phenotype, however, was associated with a reversal of this ratio, and this correlated well with the degree of histological differentiation.

Topics: Bowen's Disease; Carcinoma, Squamous Cell; Cell Differentiation; Cell Division; Humans; Immunohistochemistry; Ki-67 Antigen; Precancerous Conditions; Protein Precursors; Psoriasis; Skin; Skin Neoplasms

The cornified cell envelope (CE) is an insoluble, highly resistant structure formed beneath the plasma membrane of differentiating keratinocytes. It consists of various crosslinked precursor proteins, including involucrin and loricrin. However, neither the normal assembly process of CE nor its alteration in skin disorders has been fully characterized. In this study we analyzed CE formation in normal skin and in lesional psoriatic skin by immunoelectron microscopy. In the superficial granular cells of normal epidermis, involucrin labeling was detected along the plasma membrane, whereas loricrin staining was mostly distributed diffusely within the cells, occasionally with some additional granular aggregates within the cytoplasm and nucleus. Loricrin was also present predominantly on the desmosomal attachment plaques, colocalizing with desmoglein. In the cornified cells, involucrin labeling was reduced, whereas loricrin labeling was retained and continuously decorated the CEs, with relative sparing of the desmosomal areas. In typical psoriatic epidermis, involucrin staining was very intense but loricrin labeling was markedly reduced. The involucrin-positive CEs were formed precociously and further maturation of CE did not occur. These results suggest that formation of CE occurs sequentially, initially involving involucrin deposition and subsequently involving loricrin incorporation. Psoriatic epidermis demonstrates a lack of proper CE maturation.

Topics: Aged; Aged, 80 and over; Animals; Cell Membrane; Cytoskeletal Proteins; Desmogleins; Desmoplakins; Epidermis; Female; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Keratinocytes; Male; Membrane Proteins; Mice; Microscopy, Immunoelectron; Middle Aged; Protein Precursors; Psoriasis; Rabbits

Lesional psoriatic epidermis displays a number of phenotypic changes that are distinct from the differentiation program found in normal interfollicular epidermis. In psoriatic epidermis, keratinocytes are hyperproliferative and several differentiation-associated molecules are expressed that are absent in normal skin (e.g., cytokeratins (CK) 6, 16, and 17, and the epidermal proteinase inhibitor SKALP/ elafin). In addition, several molecules which are normally restricted to the stratum granulosum are strongly upregulated in the stratum spinosum (e.g., psoriasis-associated fatty acid binding protein (PA-FABP), psoriasin, involucrin, and transglutaminase). The aim of this study was to develop in vitro culture systems which (a) would allow to study the induction of normal and psoriatic differentiation pathways, and (b) would be amenable for screening of antipsoriatic drugs. Here we have investigated several models for induction of differentiation with respect to the expression of markers for the normal and psoriatic phenotype. Cell cycle parameters and expression levels of CK1, CK10, CK16, SKALP/elafin, transglutaminase, involucrin, psoriasin, and PA-FABP were assessed in these models using flow cytometry, immunocytochemistry, and Northern blot analysis. We observed that induction of differentiation with fetal calf serum resembled the psoriatic phenotype (sustained hyperproliferation; high levels of CK16, SKALP/elafin, transglutaminase, and involucrin; moderate psoriasin expression), whereas differentiation induced by growth factor depletion in a confluent culture resembled the normal differentiation phenotype (low proliferative rate; high expression levels of CK1 and CK10; moderate expression of involucrin and transglutaminase; low expression levels of SKALP/elafin and CK16; absence of psoriasin). We propose that these models can be used to study expression and pharmacological modulation of selected differentiation genes and the coordinated expression of sets of genes associated with epidermal differentiation programs.

Topics: Blotting, Northern; Carrier Proteins; Cell Culture Techniques; Cell Differentiation; Cells, Cultured; Culture Media; Fatty Acid-Binding Protein 7; Fatty Acid-Binding Proteins; Flow Cytometry; Humans; Immunohistochemistry; Keratinocytes; Keratins; Membrane Proteins; Myelin P2 Protein; Neoplasm Proteins; Phenotype; Protein Precursors; Proteinase Inhibitory Proteins, Secretory; Proteins; Psoriasis; RNA, Messenger; Serine Proteinase Inhibitors; Transglutaminases; Tumor Suppressor Proteins

The aromatic retinoids etretinate and acitretin are widely used in the systemic treatment of severe psoriasis. The purpose of the present investigation was to further elucidate the mode of action of acitretin on abnormal keratinization and epidermal hyperproliferation in an in vivo model. Studies on the interference of acitretin with epidermal hyperproliferation and abnormal keratinization in psoriatic plaques are difficult to interpret, as acitretin-induced changes might be due to direct effects of acitretin or be the indirect effect of retinoid-induced modulation of cutaneous inflammation. Using an immunohistochemical assessment, we examined the in vivo effect of systemic acitretin ( > 35 mg daily) on the expression of filaggrin, involucrin, and on the recruitment of cycling epidermal cells, in the tape-stripped uninvolved skin of psoriatic patients, a model which provides the opportunity to study epidermal regeneration in the absence of significant accumulation of T-lymphocytes. During acitretin therapy and 3 weeks after withdrawal of acitretin, we took biopsies from uninvolved skin following tape-stripping in 6 patients with psoriasis. Six patients with psoriasis who had never used acitretin served as controls. We did not observe a Koebner response in our patients after tape stripping. Filaggrin expression was decreased, while the recruitment of cycling epidermal cells and the involucrin expression were increased in the biopsies taken from patients who did not use acitretin. During acitretin treatment, however, the filaggrin expression was similar, whereas the Ki-67 positive nuclei and the involucrin expression showed a statistically significant decrease compared to those parameters in the patients who did not use acitretin. Our findings indicate that epidermal hyperproliferation and abnormal keratinization are modulated directly by acitretin.

Topics: Acitretin; Adult; Aged; Antibodies, Monoclonal; Bandages; Biopsy; Cell Division; Filaggrin Proteins; Humans; Immunohistochemistry; Intermediate Filament Proteins; Keratolytic Agents; Ki-67 Antigen; Middle Aged; Neoplasm Proteins; Nuclear Proteins; Protein Precursors; Psoriasis; Skin; T-Lymphocytes

Psoriatic hyperproliferative epidermis is characterized by a decreased beta 2-adrenergic adenylate cyclase response as well as by altered differentiation markers that include decreased loricrin and increased involucrin. Using a quantitative reverse transcription-polymerase chain reaction, we analysed the expression of beta 2-adrenergic receptor-mRNA, loricrin-mRNA, and involucrin-mRNA in the epidermis of five patients with psoriasis vulgaris. The mRNAs of the beta 2-adrenergic receptor and loricrin in the involved epidermis were significantly decreased, by 0.35-fold (P < 0.01) and 0.55-fold (P < 0.05) respectively, compared with uninvolved epidermis. In contrast, the involucrin mRNA expression of the involved epidermis was significantly increased, by 3.77-fold (P < 0.01). No significant difference in beta-actin mRNA transcripts was detected between the involved and the uninvolved epidermis. These results indicate that the altered expression of the beta 2-adrenergic receptor, loricrin, and involucrin, in the psoriatic involved epidermis, is associated with different amounts of each mRNA transcripts.

Topics: Actins; Adult; Base Sequence; Epidermis; Female; Humans; Male; Membrane Proteins; Middle Aged; Molecular Sequence Data; Polymerase Chain Reaction; Protein Precursors; Psoriasis; Receptors, Adrenergic, beta-2; RNA, Messenger

Epidermal keratinocytes form a cornified cell envelope (CE) beneath the plasma membrane during the late stages of differentiation. This CE is stabilized by cross linking of several precursor proteins, including involucrin. In psoriasis, the expression pattern of the precursor proteins is known to be deranged; involucrin expression is increased and loricrin expression is decreased. However, these changes have not been previously evaluated ultrastructurally. In the present study, we performed light and electron microscopic immunohistochemistry in conjunction with conventional transmission electron microscopy to assess the nature of involucrin involvement in normal and psoriatic CE. In normal epidermis, CEs were observed from the deepest cornified cells or, when present, from the transitional cells, increasing in thickness and changing electron densities with maturation. In psoriatic epidermis, CE formation started earlier, one to several cells below the cornified layer. Psoriatic CEs were generally thinner and showed a constant high electron density. Immunoelectron microscopy revealed that the normal CE was involucrin positive only at a very early stage, whereas psoriatic CE showed persistent involucrin immunoreactivity. These results suggest that in normal skin, involucrin is the major constituent of the CE only in its early stages of assembly. In contrast, CE formation seems to be initiated prematurely in psoriatic skin, where involucrin remains the major constituent of the CE during maturation.

Topics: Aged; Cell Membrane; Female; Humans; Immunohistochemistry; Male; Microscopy, Immunoelectron; Middle Aged; Protein Precursors; Psoriasis

Integrin expression is normally confined to the basal layer of the epidermis, but when epidermal homeostasis is perturbed, the receptors are also expressed by suprabasal, differentiating keratinocytes. We have used the involucrin promoter to express functional human integrin subunits alpha 2, alpha 5, and beta 1 in the suprabasal epidermal layers of transgenic mice. In mice expressing alpha 5 or beta 1 alone or alpha 2 beta 1 or alpha 5 beta 1 heterodimers, there were hair and whisker abnormalities and a failure of eyelid fusion. In addition, mice expressing beta 1 alone or in combination with alpha 2 or alpha 5 exhibited epidermal hyper-proliferation, perturbed keratinocyte differentiation, and skin inflammation, all of which are features of a common human skin disease, psoriasis.

Topics: Animals; Cell Adhesion; Cell Differentiation; Cell Division; Crosses, Genetic; Embryonic and Fetal Development; Epidermis; Eyelids; Hair; Homeostasis; Humans; Integrins; Keratinocytes; Mice; Mice, Transgenic; Promoter Regions, Genetic; Protein Precursors; Psoriasis; Skin; Skin Abnormalities; Vibrissae

It is well established that cyclosporin A (CyA), a widely used immunosuppressant in human organ transplantation, is an effective drug in the treatment of psoriasis. Although it has been postulated that the effect of CyA in psoriasis is mediated through antilymphocyte activity, there is also evidence suggesting that CyA exerts a direct cytostatic effect on epidermal keratinocytes, but results of studies relating to the latter have been contradictory. Using immunohistochemical methods we investigated the influence of systemic CyA on proliferation and differentiation in the tape-stripped uninvolved skin of psoriatic patients, a model which provides the opportunity of studying epidermal regeneration in the absence of a significant accumulation of T lymphocytes. We addressed the question of whether CyA (3-5 mg/kg/day) modulates epidermal proliferation and differentiation following standardized injury in uninvolved skin of psoriatic patients. Ten patients with severe psoriasis participated in this study. The dosages of CyA were sufficient to induce a marked and statistically significant improvement (PASI, week 0, 20.5 +/- 4.4; PASI, week 16, 4.3 +/- 0.6). Before CyA treatment, and during week 16 of treatment, Sellotape stripping was carried out on a 2-cm2 area of the uninvolved skin of psoriatic patients. After 48 h punch biopsies were taken. Immunohistochemical assessment of recruitment of cycling cells (Ki-67), filaggrin, involucrin, T lymphocytes and tenascin, was carried out. We did not find any significant alteration during the treatment period in the tape-stripped uninvolved skin of psoriatic patients. We conclude that epidermal hyperproliferation and abnormal keratinization are not modulated directly by CyA at therapeutic doses in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Cell Adhesion Molecules, Neuronal; Cell Differentiation; Cell Division; Cyclosporine; Epidermis; Extracellular Matrix Proteins; Filaggrin Proteins; Humans; Immunohistochemistry; Intermediate Filament Proteins; Keratinocytes; Ki-67 Antigen; Neoplasm Proteins; Nuclear Proteins; Protein Precursors; Psoriasis; T-Lymphocytes; Tenascin

The aim of the present study was to investigate the response of normal human skin to repeated courses of Sellotape stripping. The skin of healthy volunteers was stripped five times at 24-h intervals. Skin biopsies were taken before stripping (day 0) and on days 2, 4, 7 and 10. The responses were studied using H & E staining and an immunohistochemical analysis of several aspects of epidermal proliferation and keratinization. Although increased proliferation (nuclear binding to Ki-67 binding), acanthosis and parakeratosis were observed, the overall histological picture did not resemble psoriatic histology completely: no micropustules of Kogoj and no thinning of the suprapapillary plate were observed. Involucrin staining followed the recruitment of cycling epidermal cells showing a statistically significant elevation of positive cell layers from day 2 onwards. Filaggrin expression showed an increase from day 2 onwards, which was statistically significant on day 7 and day 10. Using the anti-keratin antibodies KS8.12 (K13 and K16) and RKSE60 (K10) we observed a fast induction of K13/K16 expression, while the staining of keratin 10 showed the same overall intensity at different time intervals. In conclusion, the response to repeated courses of tape stripping provides an adequate model for studies on epidermal proliferation, hypergranulosis and hyperkeratosis. This approach causes a more prolonged induction of these phenomena than a single course of stripping. In contrast to the situation following a single course of stripping, repeated tape stripping induced the expression of filagrin. Therefore the repeated tape stripping model is less compatible with psoriasis than a single course of stripping.

Topics: Adolescent; Adult; Cell Division; Female; Filaggrin Proteins; Humans; Immunohistochemistry; Intermediate Filament Proteins; Ki-67 Antigen; Male; Neoplasm Proteins; Nuclear Proteins; Protein Precursors; Psoriasis; Skin; Staining and Labeling

Topics: Bandages, Hydrocolloid; Biomarkers; Colloids; Epidermis; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Keratins; Occlusive Dressings; Protein Precursors; Psoriasis; Skin

The expression of cornifin, a putative cross-linked envelope precursor, was investigated in several squamous differentiating tissues by in situ hybridization and immunohistochemical analysis. Cornifin mRNA and protein, which are absent in the normal mucociliary tracheal epithelium, are induced in the suprabasal layers of the squamous metaplastic tracheal epithelium of vitamin A-deficient hamsters. Similar to the induction of squamous metaplasia in vivo, culture of rabbit tracheal cells in the absence of retinoids results in squamous differentiation and expression of cornifin. This induction of cornifin expression is suppressed by retinoic acid and several of its analogs. Cornifin mRNA and protein are also detected in the suprabasal layers of the squamous epithelium of rabbit esophagus and tongue. The distribution of cornifin in human epidermis was compared with that of two other crosslinked envelope precursor proteins, involucrin and loricrin. The localization of cornifin and involucrin is very similar. Both are induced in the spinous layer and appear at an earlier stage during epidermal differentiation than loricrin. The expression of cornifin is greatly increased in psoriatic skin. Cornifin mRNA is barely detectable in normal epidermis, whereas it is present at relatively high levels in the suprabasal layers of psoriatic epidermis. Topical treatment with RA results in thickening of the skin and increases the level of cornifin mRNA and protein in the upper spinous layers of mouse skin. Cornifin expression correlates generally with squamous differentiation in a variety of tissues and is abnormally regulated in psoriatic skin and in skin treated topically with retinoic acid.

Topics: Administration, Topical; Animals; Cells, Cultured; Cornified Envelope Proline-Rich Proteins; Cricetinae; Esophagus; Gene Expression; Humans; Male; Membrane Proteins; Mice; Protein Precursors; Psoriasis; Rabbits; RNA, Messenger; Skin; Trachea; Tracheal Neoplasms; Tretinoin; Vitamin A Deficiency

In normal epidermis, as previously reported, the first signs of differentiation occur within the basal layer in a subpopulation of keratinocytes that start to express K1 and K10 "supra-basal" keratin transcripts (20-30% of the basal cells) and proteins (5-10% of the basal cells). We found that in psoriatic lesions, the basal layer was devoid of cells expressing these early differentiation markers. This was already the case at the periphery of the lesions, where epidermis, although slightly acanthotic, still completes the keratinization process. In the center of the lesions, not only the basal layer, but also several rows of suprabasal cells, were negative for keratin K10 transcripts or protein. Moreover, the upper nucleated layers of involved epidermis were also devoid of K10 keratin transcripts or proteins. In normal epidermis, as previously reported, transcripts for the "basal" K5 keratin were mainly restricted to the basal layer, whereas the protein persisted in a few suprabasal layers. We found that in psoriatic epidermis, K5 keratin transcripts persisted in several suprabasal layers up to the level where K10 keratin transcripts appeared. These data, although not contradictory with previous reports showing a reduction of K1-K10 keratins and other differentiation markers in psoriasis, demonstrate that these quantitative changes are in fact the result of major qualitative differences in the distribution of these markers in psoriatic versus normal skin. Our results indicating that the onset of differentiation is delayed in psoriasis show that, contrary to conclusions accepted so far, not only the suprabasal compartment, but also the basal one, is abnormal in psoriatic epidermis.

Topics: Cell Differentiation; Epidermis; Humans; Keratins; Protein Precursors; Psoriasis; RNA Probes; RNA, Messenger

The immunohistochemical distribution of the epidermal proteins filaggrin, involucrin, and cytokeratins is characteristic in normal epidermis. This distribution may change as a result of malignant transformation or abnormal differentiation. The present study was conducted to determine the patterns of reactivity of psoriatic epidermis to antibodies against various epidermal proteins and to clarify abnormal differentiation or maturation of the keratinocytes in psoriatic epidermis. Anti-human filaggrin, anti-human involucrin, and twelve kinds of anti-cytokeratin antibodies were used in this study. Cryostat or paraffin-embedded sections were stained with these antibodies by the avidin-biotin peroxidase technique. The epidermis of the noninvolved skin of patients with psoriasis vulgaris showed the distribution seen in normal skin. However, involved psoriatic skin revealed little or no reaction in the stratum corneum or in the granular layer with the anti-filaggrin antibody. Cells positively staining with anti-involucrin antibody paradoxically appeared in the lower cell layers of involved psoriatic epidermis. An anti-keratin antibody, AE1, stained suprabasal cells in involved psoriatic epidermis, although this antibody selectively stained epidermal basal cells in normal skin. The other anti-keratin antibodies, especially KL1, PKK1, and a polyclonal anti-keratin antibody, were less reactive with involved psoriatic skin than with normal skin. These observations suggest that the maturation pathway of keratinocytes in active psoriatic lesions differs qualitatively from that in normal epidermis.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Autoantibodies; Cell Differentiation; Epidermis; Female; Filaggrin Proteins; Humans; Immunohistochemistry; Intermediate Filament Proteins; Keratins; Male; Middle Aged; Protein Precursors; Psoriasis; Skin

At present little is known about the control mechanisms involved in coordinating cell production and maturation in epidermis. To investigate this, we have measured the rate of transit from the proliferative to the terminally differentiating compartment in confluent low-calcium cultures of normal epidermal keratinocytes, using involucrin as a marker of terminal differentiation. We estimate a rate of transit of 3.58 cells/5000 cells/h and a differentiation probability of 0.017, indicating a bias toward self-renewal. Surprisingly, some cells in culture synthesized DNA and expressed involucrin simultaneously. In psoriatic plaques, involucrin expression begins closer to the basal layer than in normal epidermis, and here too we found S-phase involucrin-positive cells. We also observed occasional mitotic involucrin-positive cells in psoriatic epidermis, although we were unable to detect them in culture. Our experiments show that temporal separation of proliferation and terminal differentiation is not obligatory, and thus, the kinetic organization of epidermis may be less rigid than some models imply.

Topics: Cell Differentiation; Cells, Cultured; Epidermal Cells; Epidermis; Humans; Interphase; Protein Precursors; Psoriasis; Time Factors

We compared the distribution in psoriatic skin of three different markers usually found in the stratum granulosum of normal skin. Using dansylcadaverine, we demonstrate that epidermal transglutaminase activity can be detected in most of the suprabasal layers of involved psoriatic skin and that the epidermal transglutaminase activity closely matches involucrin distribution. The glycoprotein GP37 was not detected in involved psoriatic skin of stable lesions. These results suggest that the integrated control of several independent pathways of terminal differentiation is lost in psoriasis, resulting in the classical feature of parakeratosis with absence of the stratum granulosum.

Topics: Cell Differentiation; Epidermis; Fluorescent Antibody Technique; Glycoproteins; Humans; Protein Precursors; Psoriasis; Skin; Transglutaminases

We compared the maturation pathway of normal and psoriatic epidermis using three different markers: (1) Involucrin, which is normally detected in the stratum granulosum in normal skin, was detected in all but the basal layer of involved psoriatic skin; (2) an antigen, recognized by the murine monoclonal antibody psi 3, was present in all but the basal layer of involved psoriatic skin but was absent from uninvolved and normal skin; (3) fibronectin, which normally localizes in the dermis and the epidermal-dermal junction, was also detected intra- and extracellularly in the psoriatic epidermis. These results indicate that the alterations in keratinocyte maturation found in psoriasis do not arise from a truncation of the normal maturation pathway but rather reflect the onset of an abnormal pathway of differentiation characterized by the expression of psi 3 antigen and fibronectin and the premature appearance of involucrin.

Topics: Antibodies, Monoclonal; Basement Membrane; Cell Differentiation; Epidermis; Fibronectins; Fluorescent Antibody Technique; Humans; Protein Precursors; Psoriasis; Skin