transforming-growth-factor-alpha and Psoriasis

Transforming growth factor alpha (TGF alpha) is a close relative of epidermal growth factor (EGF), the first polypeptide mitogen discovered in 1962 (Cohen, 1962). TGF alpha, like EGF, exerts its effect on cells through binding to the EGF-Receptor (EGF-R). Here we review the molecular and cell biology of TGF alpha before proceeding to describe our own work on signaling molecules induced in response to activation of the EGF-R.

Topics: Amino Acid Sequence; Animals; Cell Transformation, Neoplastic; Epidermal Growth Factor; ErbB Receptors; Humans; Models, Biological; Molecular Sequence Data; Protein Structure, Secondary; Psoriasis; ras Proteins; Signal Transduction; Transforming Growth Factor alpha

The expression of several proto-oncogenes and growth factors was analyzed in normal skin and psoriatic lesions by RNA blot hybridization. Isolation of intact RNA from frozen biopsy samples required immediate exposure to denaturants during tissue homogenization. Lipocortin II and cyclophilin transcripts were used as internal controls. These transcripts were abundant and slightly but significantly elevated in psoriatic lesions. When results were normalized according to these reference transcripts, there was no increase in the expression of c-myc, c-Ha-ras, c-erbB (EGF receptor), c-jun, or transforming growth factor-beta (TGF-beta) transcripts in psoriatic lesions, and lesional c-fos transcripts were decreased relative to normal skin. In contrast, expression of TGF-alpha mRNA transcripts were markedly increased in psoriatic lesions even after normalization. Placement of normal or psoriatic tissue in organ culture for 2 to 4 h resulted in strong induction of c-fos, c-jun, and c-myc transcripts, but not of the other genes studied. Thus, overexpression of proto-oncogenes may be more characteristic of the epidermal response to acute injury than of the steady-state hyperplasia characteristic of psoriasis. Interferon-gamma (IFN-gamma) increased TGF-alpha mRNA levels in cultured human KC at long time intervals (24-48 h). However, of various cytokines tested, only EGF and TGF-alpha induced TGF-alpha mRNA after short time intervals (2-4 h). These results as well as the selective overabundance of TGF-alpha mRNA in psoriatic lesions among various cytokines tested suggest that activation of the EGF receptor tyrosine kinase by TGF-alpha is important in the pathogenesis of psoriatic epidermal hyperplasia.

Topics: ErbB Receptors; Humans; Interferon-gamma; Nucleic Acid Hybridization; Proto-Oncogene Mas; Proto-Oncogenes; Psoriasis; RNA, Messenger; Transforming Growth Factor alpha

The demonstration of activated T lymphocytes, HLA-DR+ I-CAM 1+, gamma IP-10+ keratinocytes, and increased levels of lymphokines in active plaques suggests that immunologic mechanisms may play a role in the pathogenesis of psoriasis. Epidermal hyperplasia and inflammation in psoriasis may be linked by those cytokines many of which are produced by both keratinocytes and leukocytes. Epidermal acanthosis and keratinocyte mitoses have been observed in delayed-type hypersensitivity reactions and after the intradermal injection of gamma interferon. Gamma interferon and its induced proteins have been demonstrated in active psoriatic plaques. Increased levels of the keratinocyte autocrine cytokines, transforming growth factor (TGF)-alpha and interleukin (IL)-6, have been detected in active plaques. The apparent overexpression of IL-6 in hyperplastic psoriatic tissue may explain features of psoriasis that link keratinocyte proliferation with immune activation and tissue inflammation. Both IL-6 and gamma interferon increased TGF-alpha expression in normal cultured keratinocytes. Cytokines produced during immune activation and other inflammatory processes may lead to epidermal hyperplasia.

Topics: Chemokine CXCL10; Chemokines, CXC; HLA-DR Antigens; Humans; Interleukin-1; Interleukin-6; Psoriasis; Transforming Growth Factor alpha

Protein expression is disturbed in the psoriatic stratum corneum (SC). Noninvasive methods for the description of pathophysiological changes and drug profiling in psoriasis are desirable.. Undertake large-scale noninvasive protein expression studies in psoriatic SC to identify biomarkers of pathophysiological processes and use them for drug profiling.. Psoriatic SC was harvested through repetitive tape-stripping. Nonlesional and lesional SC, as well as vehicle-treated and drug-treated lesional SC samples were collected. Protein extracts from nonlesional and lesional skin biopsies were used for comparison. Calcipotriol-betamethasone (CB) was used as a reference medication. Proteins extracted from pooled tape strips were quantified using mass spectrometry (MS), Western blotting, enzyme-linked immunosorbent assay and Luminex technologies.. MS-based methods identified 140 proteins differentially expressed in psoriatic SC. Epidermis development, glycolysis, regulation of apoptosis, cytoskeleton organization and peptide cross-linking were modulated, all reflecting perturbed epidermal differentiation. Using antibody-based techniques, increased levels of sICAM1, of CXCL1- and CXCL8-attracting neutrophils, of CXCL10- and CCL4-attracting T helper (Th) 1 cells, and of CCL2- and CCL4-attracting monocytes and dendritic cells were observed. Quantification of the Th1 and Th17 markers tumour necrosis factor, interleukin (IL) 12B, IL17A and IL17F in lesional SC was successful, while the Th2 cytokines IL4, IL5 and IL13, not involved in the disease process, were not detected. The pruritic cytokine IL31 was detected in lesional SC. CXCL1, CXCL8, CXCL10 and sICAM were used to investigate disease remission, ranking three topical treatments according to their known clinical efficacy.. Protein biomarker quantification in psoriatic SC detects key pathophysiological mechanisms and enables noninvasive drug profiling in translational medicine settings.

Topics: Biomarkers; Cells, Cultured; Chemokines, CXC; Cytokines; Dendritic Cells; Epidermis; Humans; Monocytes; Neutrophil Infiltration; Proteins; Proteome; Psoriasis; Th1 Cells; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A

Thioredoxin-interacting protein (TXNIP), also known as Vitamin-D upregulated protein-1 (VDUP-1), interacts with thioredoxin to regulate redox responses and participates in diverse disorders including metabolic, cardiovascular, inflammatory and malignant diseases. Psoriasis is characterized by chronic skin inflammation and an aberrant pattern of keratinocyte differentiation. Clinically, psoriasis is associated with various cardiometabolic comorbidities but studies on TXNIP's biological role in skin disorders are limited. In this study, we investigated TXNIP expression in psoriasis and its regulation in normal human epidermal keratinocytes (NHEKs), and then explored how TXNIP regulated skin keratinocyte differentiation to determine its role in psoriasis pathogenesis. Our immunohistochemical study demonstrated extensive TXNIP expression in the upper and lower epidermis of psoriasis compared to predominant TXNIP expression in the basal layer of normal skin. 1, 25-dihydroxyvitamin D

Topics: Carrier Proteins; Epidermal Growth Factor; ErbB Receptors; Humans; Keratinocytes; Psoriasis; Thioredoxins; Transforming Growth Factor alpha

Psoriasis is characterized by excessive growth and aberrant differentiation of epidermal keratinocytes due to persistent inflammation. However, the underlying mechanism that triggers immune activation in psoriasis is not clear. In this study, we explored excessive DNA as a potential trigger of psoriasis using cultured human keratinocytes and psoriatic skin tissues. We demonstrated that human genomic DNA fragments induced tumour necrosis factor (TNF)-α expression, hyperproliferation and over-expression of heparin-binding epidermal-like growth factor (HB-EGF) and transforming growth factor (TGF)-α, accompanied by defective expression of keratins 1 and 10 in cultured normal human epidermal keratinocytes, which have a similar phenotype to that of keratinocytes in psoriatic skin lesions. In psoriatic lesions, we found high levels of double-stranded (ds)DNA fragments, accompanying keratinocytes expressing Ki-67, HB-EGF and TNF-α. In addition, we showed that 1,25-dihydroxyvitamin D

Topics: Cell Line; Cell Proliferation; DNA; DNA Fragmentation; Heparin-binding EGF-like Growth Factor; Humans; Interleukin-1beta; Keratinocytes; Ki-67 Antigen; Psoriasis; Transforming Growth Factor alpha; Tumor Necrosis Factor-alpha

TNF-α plays a crucial role in psoriasis; therefore, TNF inhibition has become a gold standard for the treatment of psoriasis. TNF-α is processed from a membrane-bound form by TNF-α converting enzyme (TACE) to soluble form, which exerts a number of biological activities. EGF receptor (EGFR) ligands, including heparin-binding EGF-like growth factor (HB-EGF), amphiregulin and transforming growth factor (TGF)-α are also TACE substrates and are psoriasis-associated growth factors. Vascular endothelial growth factor (VEGF), one of the downstream molecules of EGFR and TNF signaling, plays a key role in angiogenesis for developing psoriasis. In the present study, to assess the possible role of TACE in the pathogenesis of psoriasis, we investigated the involvement of TACE in TPA-induced psoriasis-like lesions in K5.Stat3C mice, which represent a mouse model of psoriasis. In this mouse model, TNF-α, amphiregulin, HB-EGF and TGF-α were significantly up-regulated in the skin lesions, similar to human psoriasis. Treatment of K5.Stat3C mice with TNF-α or EGFR inhibitors attenuated the skin lesions, suggesting the roles of TACE substrates in psoriasis. Furthermore, the skin lesions of K5.Stat3C mice showed down-regulation of tissue inhibitor of metalloproteinase-3, an endogenous inhibitor of TACE, and an increase in soluble TNF-α. A TACE inhibitor abrogated EGFR ligand-dependent keratinocyte proliferation and VEGF production in vitro, suggesting that TACE was involved in both epidermal hyperplasia and angiogenesis during psoriasis development. These results strongly suggest that TACE contributes to the development of psoriatic lesions through releasing two kinds of psoriasis mediators, TNF-α and EGFR ligands. Therefore, TACE could be a potential therapeutic target for the treatment of psoriasis.

Topics: ADAM Proteins; ADAM17 Protein; Amphiregulin; Animals; Disease Models, Animal; EGF Family of Proteins; Gene Expression Regulation; Humans; Mice; Psoriasis; Skin; Tetradecanoylphorbol Acetate; Transforming Growth Factor alpha; Tumor Necrosis Factor-alpha; Up-Regulation

Recent advances in the knowledge of the EGFR pathway have revealed its contribution to distinct immune/inflammatory functions of the epidermis. The purpose of our study was to evaluate the role of EGFR in the regulation of keratinocyte GM-CSF expression. In cultured human keratinocytes, proinflammatory cytokines synergized with TGF-alpha to induce GM-CSF expression. Accordingly, high epidermal levels of EGFR activation are associated with enhanced expression of GM-CSF in lesional skin of patients with psoriasis or allergic contact dermatitis. In cultured keratinocytes, pharmacological inhibition of EGFR activity reduced GM-CSF promoter transactivation, whereas genetic inhibition of AP-1 reduced expression of GM-CSF. Furthermore, EGFR activation enhanced TNF-alpha-induced c-Jun phosphorylation and DNA binding, whereas c-Jun silencing reduced GM-CSF expression. Using two different mouse models, we showed that the lack of a functional EGFR pathway was associated with reduced cytokine-induced phosphorylation of ERK1/2, JNK1/2, c-Jun and reduced keratinocyte-derived GM-CSF expression both in vitro and in vivo. Finally, the analysis of GM-CSF expression in the skin of cancer patients treated with anti EGFR drugs showed an association between ERK activity, c-Jun phosphorylation, and epidermal GM-CSF expression. These data demonstrate that the EGFR pathway is critical for the upregulation of keratinocyte GM-CSF expression under conditions of cytokine stimulation.

Topics: Adult; Aged; Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Cells, Cultured; Cetuximab; Dermatitis, Atopic; Drug Eruptions; ErbB Receptors; Female; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; In Vitro Techniques; Interferon-gamma; JNK Mitogen-Activated Protein Kinases; Keratinocytes; Male; MAP Kinase Signaling System; Mice; Mice, Inbred Strains; Mice, Mutant Strains; Middle Aged; Phosphorylation; Psoriasis; Transcription, Genetic; Transforming Growth Factor alpha

IL-20 cytokine subfamily members, including IL-19, IL-20, and IL-24, are highly expressed in psoriatic skin lesions. Here, we demonstrate that psoriasis mediators IL-17 and IL-22 synergistically induce the production of IL-20 subfamily proteins in cultured human keratinocytes. Interestingly, expression of the IL-22 receptor (IL-22R) also increased in epidermal lesions versus normal skin. IL-22R over-expression using an adenoviral vector to mimic psoriatic conditions in cultured keratinocytes significantly enhanced IL-17- and IL-22-induced production of IL-20 subfamily cytokines. Furthermore, IL-17 and IL-22 coordinately enhanced MIP-3alpha, IL-8, and heparin-binding EGF-like growth factor (HB-EGF) production, depending on the amount of IL-22R expression. Additionally, because IL-20 and IL-24 share the IL-22R with IL-22, the function of IL-20 and IL-24 was also increased. IL-20 and IL-24 have effects similar to that of IL-22; IL-24 showed more potent expression than IL-20. A combination of IL-24 and IL-17 increased the production of MIP-3alpha, IL-8, and HB-EGF, as did a combination of IL-22 and IL-17. These data indicate that increased IL-22R expression in epidermal keratinocytes contributes to the pathogenesis of psoriasis through enhancing the coordinated effects of IL-22 and IL-17, inducing the production of the IL-20 subfamily, chemokines, and growth factors.

Topics: beta-Defensins; Cells, Cultured; Chemokine CCL20; Epidermis; Gene Expression; Heparin-binding EGF-like Growth Factor; Humans; Intercellular Signaling Peptides and Proteins; Interferon-gamma; Interleukin-10 Receptor beta Subunit; Interleukin-17; Interleukin-1alpha; Interleukin-22; Interleukin-8; Interleukins; Keratinocytes; Models, Biological; Phosphorylation; Psoriasis; Receptors, Interleukin; STAT3 Transcription Factor; Transduction, Genetic; Transforming Growth Factor alpha; Tumor Necrosis Factor-alpha

Epidermal hyperproliferation and neutrophil infiltration are major histopathological changes observed in psoriasis. Neutrophils contain human leukocyte elastase (HLE), which is released at sites of inflammation. HLE is present in psoriatic lesions and induces keratinocyte hyperproliferation in vitro and in vivo. To determine the molecular mechanisms linking a proteolytic effect of HLE and epidermal hyperproliferation, we examined the effects of HLE-induced signaling in human keratinocytes. Application of 100 nM HLE resulted in a transient calcium influx in FURA2-loaded human HaCaT keratinocytes observed by single-cell fluorescence imaging. The calcium signal was concentration dependent and was inhibited by addition of the HLE inhibitors elafin and secretory leukocyte protease inhibitor. The calcium signal was neither inhibited by pertussis toxin, cholera, or by pre-stimulation with trypsin. Incubation with the tyrosine kinase inhibitor genistein, a protein kinase C inhibitor, as well as incubation with neutralizing EGFR antibodies abolished the HLE-induced calcium influx. The supernatants of HLE-treated keratinocytes induced a calcium signal in separately cultured keratinocytes. This could be inhibited by the addition of anti-TGF-alpha antibodies. Application of HLE-induced keratinocyte proliferation, which could be inhibited by neutralizing of anti-EGFR and anti-TGF-alpha antibodies. Herein we demonstrate that HLE induces keratinocyte proliferation by proteolytic activation of an EGFR signaling cascade involving TGF-alpha.

Topics: Calcium; Calcium Signaling; Cell Division; Cell Line, Transformed; ErbB Receptors; Humans; Keratinocytes; Leukocyte Elastase; Psoriasis; Transforming Growth Factor alpha

Keratinocytes release a number of cytokines interacting with other intra- and subepidermal cells during the initiation and the perpetuation of skin inflammatory reactions. Cultured human keratinocytes overexpressing the transforming growth factor alpha (TGF-alpha) assumed a spindled morphology and displayed increased locomotion. Moreover, the receptor for TGF-alpha, the epithelial growth factor receptor (EGFR), is important for autocrine growth, promotion of cell survival, and regulation of cell migration. The expression of TGF-alpha and EGFR has not been widely studied in human developing skin and their roles in geno-dermatosis are not known. In this study, we investigated the expression of TGF-alpha and EGFR by immunohistochemistry in human developing skin at different gestational ages (14 th week, 20 th week, and 34 th week), in six patients with psoriasis, and, for the first time, in an infant affected with restrictive dermopathy, a very rare lethal genodermatosis, characterized by abnormal skin growth and differentiation with thin, tightly adherent skin. TGF-alpha and EGFR were expressed in the basal layer at the 14 th week and in all epidermal layers at the 20 th and 34 th week of gestation. In psoriasis, TGF-alpha was overexpressed in all layers of epidermis, while EGFR was expressed in the basal and first suprabasal layers. In restrictive dermopathy, we observed no expression of both TGF-alpha and EGFR at the level of the skin. The other organs showed comparable patterns to those of an age-matched infant. In conclusion, TGF-alpha and EGFR interact strictly to promote skin development during the intrauterine life. An interactive autocrine growth cycle between TGF-alpha and EGFR is present in psoriasis. A skin-localized alteration of the expression of TGF-alpha and EGFR may be at the basis of restrictive dermopathy. The delay of growth and differentiation of the skin in restrictive dermopathy may be related to the absent expression of TGF-alpha, which is probably due to a down regulation of EGFR by an abnormal autocrine mechanism.

Topics: Aged; ErbB Receptors; Female; Gestational Age; Humans; Immunohistochemistry; Infant, Newborn; Male; Middle Aged; Pregnancy; Psoriasis; Skin; Skin Diseases, Genetic; Transforming Growth Factor alpha

p70 Ribosomal protein S6 kinase is a critical down-stream effector of a mitogen-stimulated signaling pathway that is selectively inhibited by the immunosuppressant rapamycin. The purpose of this study was to quantify S6 kinase expression in psoriatic involved, uninvolved, and normal epidermis and to characterize regulation of S6 kinase activity in cultured normal human keratinocytes. S6 kinase activity was increased 4-fold in psoriatic lesions (1.63 +/- 0.25 pmol per min per mg, n = 6), compared to nonlesional (0.44 +/- 0.12 pmol per min per mg, n = 6, p < 0.01), and normal (0.35 +/- 0.14 pmol per min per mg, n = 7, p < 0.01) epidermis. In contrast, S6 kinase mRNA and protein levels were not significantly different among psoriatic lesional, nonlesional, and normal epidermis. In keratinocytes, S6 kinase activity was stimulated 3-fold by mitogenic epidermal growth factor (EGF) receptor ligands, EGF and transforming growth factor-alpha (TGF-alpha), but not by cytokines interleukin-1alpha, tumor necrosis factor-alpha, interferon-gamma, or transforming growth factor-beta1. TGF-alpha stimulation of S6 kinase activity was inhibited in a concentration-dependent manner by rapamycin (IC50 < 0.2 nM) and the specific EGF receptor antagonist PD153035 (IC50 = 20 nM). Rapamycin also inhibited EGF-stimulated proliferation of keratinocytes (IC50 = 0.2 ng per ml) with a potency similar to that reported for inhibition of T-cell proliferation. We conclude: (i) the mitogenic signaling pathway(s) regulating S6 kinase is activated in psoriatic lesions, thus accounting for increased S6 kinase activity in the absence of increased S6 kinase gene or protein expression; (ii) S6 kinase activation in lesional keratinocytes likely occurs in response to EGF receptor stimulation by TGF-alpha and/or amphiregulin, which are known to be elevated in psoriatic lesions; and (iii) keratinocyte as well as T-cell mitogenic signaling pathways are susceptible to inhibition by rapamycin, suggesting that rapamycin may be of therapeutic benefit in the treatment of psoriasis.

Topics: Adult; Cell Division; Cells, Cultured; Enzyme Activation; Epidermal Growth Factor; ErbB Receptors; Humans; Immunosuppressive Agents; Keratinocytes; Polyenes; Protein Serine-Threonine Kinases; Psoriasis; Ribosomal Protein S6 Kinases; RNA, Messenger; Sirolimus; Skin; Transforming Growth Factor alpha

Psoriasis is a chronic inflammatory disorder characterized by epidermal hyperproliferation. Although recent evidence suggests that T cell activation is a primary trigger for psoriasis lesions, there may be alterations in the keratinocyte growth regulatory pathways which induce epidermal hyperproliferation in psoriatic patients. To test this hypothesis, we investigated the proliferative activity of epidermal keratinocytes 48 h after tape stripping, one of the standard mechanical ways to stimulate the epidermis, in 20 psoriasis patients and in 18 controls. Epidermal cell kinetics were assessed with DNA flow cytometry, the mitotic index, bromodeoxyuridine incorporation, Ki-67 antigen expression and DNA polymerase alpha expression. The expression of TGF-alpha and EGF receptors, critical mediators of keratinocyte proliferation, were also investigated immunohistochemically. The results of multiparameter assays showed that the baseline proliferative activity in uninvolved skin was the same in psoriasis patients and normal controls. After tape stripping, although both psoriasis patients and the normal controls showed significant increases in epidermal cell proliferation, the values of all the parameters investigated were significantly greater in the psoriasis patients than in the normal controls. EGF receptors were overexpressed in basal and suprabasal keratinocytes after tape stripping in both the psoriasis patients and the normal controls. In contrast, overexpression of TGF-alpha was only observed in the patients with psoriasis, which may explain their increased proliferative response to trauma.

Topics: Adult; Aged; Aged, 80 and over; Bromodeoxyuridine; Case-Control Studies; Cell Division; DNA; DNA Polymerase II; ErbB Receptors; Female; Flow Cytometry; Humans; Immunohistochemistry; Keratinocytes; Ki-67 Antigen; Male; Middle Aged; Mitotic Index; Physical Stimulation; Psoriasis; Transforming Growth Factor alpha

In psoriatic lesions, epidermal keratinocytes overexpress vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) and transforming growth factor alpha (TGF-alpha). TGF-alpha has been shown to induce VEGF/VPF in normal human epidermal keratinocytes in vitro. By using a 19-mer antisense phosphorothioate oligodeoxynucleotide (PS-ODN) complementary to bases 6-24 relative to the translational start site of the VEGF/VPF mRNA, the control sense and mismatched PS-ODNs, we examined modulation of VEGF/VPF induction by TGF-alpha in vitro. Normal human epidermal keratinocytes were treated with PS-ODNs and Lipofectin for 8 h prior to the addition of TGF-alpha. Inhibition was assayed at the level of secreted protein by capture ELISA and mRNA expression was assayed by Northern blot analysis. The anti-sense PS-ODN was capable of inhibiting VEGF/VPF RNA and protein to near-basal levels. This inhibition was concentration dependent. No effect was observed with the sense or mismatch control PS-ODNs. These studies suggest that antisense oligonucleotide technology may be a potential therapy for the inhibition of angiogenesis associated with certain skin disorders such as psoriasis.

Topics: Down-Regulation; Endothelial Growth Factors; Humans; Keratinocytes; Lymphokines; Oligonucleotides; Oligonucleotides, Antisense; Psoriasis; RNA, Messenger; Skin; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Amphiregulin and transforming growth factor-alpha, agonists for the epidermal growth factor receptor, are the major autocrine growth factors for cultured keratinocytes, and their substantial overexpression in psoriatic lesions suggests that they are crucial to the basal hyperplasia that characterizes psoriasis. Amphiregulin binds to heparin and related highly sulfated polysaccharides, and exogenous heparin blocks its growth factor activity, rationalizing previous reports that psoriasis responds to heparin therapy. Differentiating keratinocytes produce increased amounts of protein-bound as well as free-chain heparan sulfates, which may function physiologically as amphiregulin antagonists. By promoting keratinocyte synthesis of these heparan sulfates, glucosamine administration may inhibit amphiregulin function and thus provide therapeutic benefit in psoriasis. Concurrent ingestion of fish oil, by impeding the excessive activation of protein kinase C, may decrease keratinocyte production of amphiregulin and other autocrine growth factors, thus complementing the postulated benefits of glucosamine.

Topics: Amphiregulin; EGF Family of Proteins; ErbB Receptors; Fish Oils; Glucosamine; Glycoproteins; Growth Substances; Heparitin Sulfate; Humans; Intercellular Signaling Peptides and Proteins; Models, Biological; Psoriasis; Transforming Growth Factor alpha

Evidence suggests an association between alcohol consumption and psoriasis. This relationship is still undefined, although long-term alcohol intake influences the immune system. Interactions between T cells and keratinocytes are important for the pathogenesis of psoriasis, by secretion of pro-inflammatory cytokines and growth factors in psoriatic skin. IL-2, IL-6, IL-8, IFN-gamma and TGF-alpha are hallmark cytokines in a psoriatic cytokine network. We investigated whether ethanol influences the secretion of these cytokines using a co-culture model with keratinocytes from psoriatic patients (n = 9) or from healthy controls (n = 9), with HUT 78 lymphocytes, and determined the cytokine levels with or without ethanol treatment in the culture supernatants. TGF-alpha and IFN-gamma levels were elevated in the ethanol-treated psoriatic co-cultures, to 150% and 175% respectively, but neither in co-cultures with keratinocytes derived from healthy control individuals nor in monocultures. Treatment with ethanol elevated slightly the IL-6 levels in the monocultures from psoriatic and control keratinocytes to 125% but not in HUT 78 monocultures. In the psoriatic co-cultures, IL-6 levels were elevated in the culture supernatants to almost 160%, but they were not influenced by ethanol in co-cultures with control keratinocytes. The cytokine levels of IL-8 or IL-2 were not significantly influenced in the psoriatic mono- and co-cultures or in HUT 78 cultures. If ethanol influences the cytokine secretion of psoriatic keratinocytes and HUT 78 lymphocytes in co-culture conditions, these data suggest that ethanol could also influence the psoriatic cytokine network in vivo, which may explain the explain the aggravation of this disease in alcohol-consuming psoriatic patients.

Topics: Coculture Techniques; Ethanol; Humans; Interferon-gamma; Interleukin-6; Keratinocytes; Psoriasis; Skin; Stimulation, Chemical; Transforming Growth Factor alpha

Keratinocytes from normal and psoriatic skin were tested for their in vitro proliferative response to a range of concentrations of rIL-6, rTGF alpha, rIL-8 and rGM-CSF using a serum-free culture system. With one exception, all normal cultures (11/12) were stimulated by 1000 ng/ml IL-6 (P < 0.001). Six out of ten psoriatic keratinocyte cultures were also stimulated at this concentration, but this just failed to reach significance (P = 0.05). As a group, the response by psoriatic keratinocytes to IL-6 was significantly less than that of normal keratinocytes (P = 0.02). TGF alpha at 1 ng/ml induced proliferation in approximately 60% of both normal (8/12, P < 0.05) and psoriatic (6/10, P < 0.01) keratinocyte cultures; there was no significant difference between the responses of the two groups to this cytokine. In addition, small numbers of both normal and psoriatic cultures responded to TGF alpha over a concentration range of 0.1 to 100 ng/ml. Approximately half of the normal and psoriatic cultures were stimulated by 10-1000 ng/ml IL-8. However, the effect was not significant for the group at any of the concentrations tested. GM-CSF had minimal to no effect on most of the normal and psoriatic cultures tested. This study showed that psoriatic keratinocytes are equally responsive to the stimulatory effects of TGF alpha and IL-8, but are less susceptible to IL-6 compared to keratinocytes from normal skin. These findings are consistent with a role for these cytokines in the maintenance of a hyperproliferative epidermis in psoriasis.

Topics: Adult; Cell Division; Cytokines; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; In Vitro Techniques; Interleukin-6; Interleukin-8; Keratinocytes; Psoriasis; Recombinant Proteins; Transforming Growth Factor alpha

Lesional psoriatic keratinocyte (LPK) culture is considered to be difficult under high-Ca2+ conditions in the absence of special proliferative agents. Using a permeable collagen membrane, we obtained a culture of LPKs under high-Ca2+ conditions without any special proliferative agents. Single-cell suspensions were prepared from the epidermis of chronic psoriatic plaques. Cells were inoculated on the collagen membrane suspended slightly above the bottom of a Petri dish. We used a culture medium of Eagle's MEM containing 10% fetal calf serum. LPKs attached to the membrane 12 h after inoculation and gradually spread. They reached a confluent state by the 10th day of culture. We measured the concentrations of TGF alpha and IL-6 in the medium of LPKs, and compared these with the concentrations in normal keratinocyte (NK) cultures. Significantly increased secretion of TGF alpha by LPKs was observed during the initial phase but this secretion subsequently decreased. Concentrations of IL-6 were below the detectable level in both of NKs and LPKs throughout the observation period. Our results demonstrate that cultured LPKs under high-Ca2+ conditions secrete a larger amount of TGF alpha but not IL-6. Our cell culture system, which allows LPKs to spread and stratify, contributes to the study of the pathogenesis of psoriasis.

Topics: Adult; Calcium; Cells, Cultured; Collagen; Culture Media; Cytological Techniques; Feasibility Studies; Female; Humans; Interleukin-6; Keratinocytes; Male; Membranes, Artificial; Microscopy, Electron; Microscopy, Phase-Contrast; Middle Aged; Osmolar Concentration; Psoriasis; Transforming Growth Factor alpha

We investigated the localization of TGF-alpha and EGF receptor in psoriatic plaques, especially the clinically-determined transitional zone from uninvolved to involved psoriatic skin by immunohistochemistry. TGF-alpha was not increased in the transitional area compared with normal epidermis. It started to increase within the edge of psoriatic plaques. In contrast, EGF receptor increased up to the suprabasal layers even in the uninvolved skin adjacent to psoriatic plaques, compared with normal epidermis. Slight epidermal hyperplasia was also observed in the clinically-determined transitional area. This result suggests that the increase of EGF receptor precedes that of TGF-alpha in psoriatic plaque formation.

Topics: Epidermis; ErbB Receptors; Humans; Hyperplasia; Immunohistochemistry; Psoriasis; Reference Values; Staining and Labeling; Transforming Growth Factor alpha

Fourteen patients with chronic plaque psoriasis requiring in-patient therapy were treated with a variety of antipsoriatic agents. All had four skin biopsies taken: two prior to therapy, one from a psoriatic plaque and one from adjacent clinically normal skin, and two further biopsies, one 2-3 weeks after starting therapy, and one at clinical clearance, taken from an area where there was previously a psoriatic plaque. In addition, three biopsies were taken from clinically normal skin of non-psoriatics. Transforming growth factor-alpha (TGF-alpha) RNA and protein distributions were estimated in these biopsies, using in situ hybridization with a cRNA TGF-alpha probe, and an antibody to TGF-alpha polypeptide. Prior to therapy, grain counts showed elevated levels of TGF-alpha RNA in the subcorneal layers of the epidermis. These levels decreased during clearance of the psoriasis. In one patient whose plaques did not clear, there was no decrease of TGF-alpha mRNA. Antibody studies showed the presence of TGF-alpha polypeptide in the epidermis prior to therapy, with a relative concentration of immunoprotein in the upper epidermal layers, compared with a more uniform distribution of immunoprotein after treatment, and in uninvolved skin of the same psoriatic patient. These studies extend our knowledge of the relationship between TGF-alpha and psoriatic skin.

Topics: Anthralin; Coal Tar; Epidermis; Etretinate; Gene Expression; Humans; Immunohistochemistry; In Situ Hybridization; Psoriasis; PUVA Therapy; RNA; Steroids; Transforming Growth Factor alpha; Ultraviolet Therapy

Psoriatic skin is characterized by microvascular hyperpermeability and angioproliferation, but the mechanisms responsible are unknown. We report here that the hyperplastic epidermis of psoriatic skin expresses strikingly increased amounts of vascular permeability factor (VPF; vascular endothelial growth factor), a selective endothelial cell mitogen that enhances microvascular permeability. Moreover, two VPF receptors, kdr and flt-1, are overexpressed by papillary dermal microvascular endothelial cells. Transforming growth factor alpha (TGF-alpha), a cytokine that is also overexpressed in psoriatic epidermis, induced VPF gene expression by cultured epidermal keratinocytes. VPF secreted by TGF-alpha-stimulated keratinocytes was bioactive, as demonstrated by its mitogenic effect on dermal microvascular endothelial cells in vitro. Together, these findings suggest that TGF-alpha regulates VPF expression in psoriasis by an autocrine mechanism, leading to vascular hyperpermeability and angiogenesis. Similar mechanisms may operate in tumors and in healing skin wounds which also commonly express both VPF and TGF-alpha.

Topics: Base Sequence; Cells, Cultured; Endothelial Growth Factors; Humans; Lymphokines; Molecular Sequence Data; Psoriasis; Receptor Protein-Tyrosine Kinases; Receptors, Growth Factor; Receptors, Vascular Endothelial Growth Factor; RNA, Messenger; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

The purpose of this study was to investigate and to compare, by in situ hybridization, gene expression of IL-1 beta, IL-8, TGF-beta 1, TGF-beta 2, TGF-beta 3, TGF-alpha, p53 and c-myc in lesions and in non-involved skin of patients with psoriasis. All lesional skin biopsies showed overexpression of IL-1 beta, IL-8 TGF-alpha mRNAs. IL-1 beta hybridization signals were strong in a small number of cells localized predominantly in the dermal papillae and in the suprapapillary epidermis. Overexpression of TGF-alpha was observed in all suprabasal keratinocytes, whereas strongly elevated IL-8 mRNA expression was found to be restricted to clusters of suprabasal keratinocytes. TGF-beta 3, p53 and c-myc transcripts were clearly detected in the epidermis of all biopsies, although expression levels were comparable in lesional and non-lesional skin.

Topics: Cytokines; Gene Expression; Genes, myc; Genes, p53; Genes, Tumor Suppressor; Humans; In Situ Hybridization; Interleukin-1; Interleukin-8; Proto-Oncogene Mas; Proto-Oncogenes; Psoriasis; Transforming Growth Factor alpha; Transforming Growth Factor beta

Anthralin is an effective topical treatment for active psoriasis; however, its mechanism of action is unknown. Both TGF-alpha and its receptor, the EGF receptor, are overexpressed in active psoriatic plaques and might, therefore, play a role in psoriatic epidermal hyperplasia. In order to assess whether anthralin might act via alteration of this growth factor pathway, we examined the in vitro effects of pharmacologic concentrations of anthralin on cultured normal human keratinocytes. Keratinocyte proliferation was inhibited by 98% at an anthralin concentration of 10 ng/ml. In contrast, lymphocyte proliferation was inhibited by only 50% at an anthralin concentration of 10 micrograms/ml. Anthralin treatment did not induce cell-cycle-specific growth arrest as assessed by flow-cytometric analysis of acridine-orange-stained keratinocytes. Northern analysis of anthralin-treated keratinocytes demonstrated a marked decrease in TGF-alpha mRNA expression. Anthralin-treated keratinocytes showed decreased binding of 125I-EGF and 125I-IGF-I to their respective receptors, but EGF receptor binding was inhibited to a greater extent. Anthralin decreased ligand-binding affinity and cell-surface numbers of EGF receptors as assessed by Scatchard analysis of 125I-EGF binding to anthralin-treated keratinocytes. These results indicate that anthralin alters components of the EGF receptor pathway in cultured keratinocytes and that these effects might contribute to the clinical efficacy of anthralin in the treatment of active psoriasis.

Topics: Anthralin; Cell Division; ErbB Receptors; Humans; Insulin-Like Growth Factor I; Keratinocytes; Psoriasis; Receptors, Cell Surface; Receptors, Somatomedin; Transforming Growth Factor alpha

Cyclosporine (CSA) decreases lymphokine synthesis and keratinocyte proliferation in vitro, but its in vivo mechanism of action in treating recalcitrant psoriasis is incompletely understood. Ten psoriasis patients were treated with CSA (2-7.5 mg/kg/d) with clinical improvement in nine of 10 patients. Skin biopsies before and after 1-3 months of CSA treatment were studied for evidence of immune and keratinocyte activation using immunoperoxidase and Northern blotting analysis. The number of activated, IL-2 receptor+ T cells in plaques after CSA treatment was reduced in all patients by a mean of 60%. Seven of 10 patients showed a decrease in keratinocyte HLA-DR expression; five of seven showed a decrease in gamma-IP-10 immunoreactivity, suggesting a decline in gamma interferon levels in plaques after CSA therapy. We studied the effect of CSA treatment in vivo on TGF-alpha, IL-6, and keratin K16 expression, three markers of keratinocyte growth activation. Expression of keratinocyte TGF-alpha and IL-6, which are elevated in active psoriatic epidermis, did not change in these patients after CSA treatment. The majority of patients (five of eight) continued to express the hyperproliferative keratin K16 after CSA treatment. Our results suggest that the predominant direct mechanism of action of Cyclosporine in vivo is a diminution of T-cell activation in plaques, with attendant decreased lymphokine production.

Topics: Cyclosporine; HLA-DR Antigens; Humans; Interleukin-6; Keratins; Lymphocyte Activation; Psoriasis; Receptors, Interleukin-2; Regeneration; Skin; T-Lymphocytes; Transforming Growth Factor alpha

Normal skin and uninvolved and involved psoriatic skin specimens were maintained in vitro in organ culture. The 3-4 mm punch-biopsied skin specimens were put freely into the culture medium with or without fetal calf serum, under an atmosphere of 95% O2 plus 5% CO2, and rotated at 60 rpm at 37 degrees C. In the serum-free culture medium (vitamin A-free) granular layers appeared in the involved psoriatic epidermis in culture. Addition of TGF-alpha caused normal skin and uninvolved and involved psoriatic skin specimens to become acanthotic and to degenerate easily almost to the full thickness of the epidermal layer in proportion to increasing concentrations of TGF-alpha as well as with the duration of the culture, but without disappearance of their granular layers. TGF-beta caused the normal skin and uninvolved psoriatic skin specimens to become thinned without disappearance of granular layers, but caused the involved psoriatic skin specimens to be thinned without appearance of granular layers in serum-containing medium or with their disappearance in the serum-free medium. TGF-beta also antagonized the acanthotic and degenerative effect of TGF-alpha. The results suggest that TGF-alpha and TGF-beta may partially be related to the induction of psoriatic epidermal lesions.

Topics: Humans; Organ Culture Techniques; Psoriasis; Skin; Transforming Growth Factor alpha; Transforming Growth Factor beta

Amphiregulin (AR) is a heparin-regulated, epidermal growth factor-like growth factor capable of stimulating the proliferation of non-tumorigenic cells while inhibiting cell proliferation in some human tumor cell lines in vitro. In the present study, we have investigated AR mRNA expression in normal, hyperproliferative, and neoplastic human epithelium. Our results demonstrate that, compared with the adjacent uninvolved epithelium, AR mRNA expression is markedly elevated in epidermal biopsies derived from three human psoriatic lesions as well as in biopsies derived from five human colon carcinomas and three human stomach carcinomas. Moreover, analysis of a colon carcinoma by in situ hybridization revealed that AR mRNA is localized to the epithelium.

Topics: Amphiregulin; Base Sequence; Blotting, Northern; Colonic Neoplasms; EGF Family of Proteins; Epithelial Cells; Epithelium; Glycoproteins; Growth Substances; Humans; Intercellular Signaling Peptides and Proteins; Molecular Sequence Data; Oligodeoxyribonucleotides; Oligonucleotides, Antisense; Psoriasis; Reference Values; RNA, Messenger; Skin; Stomach Neoplasms; Transforming Growth Factor alpha

Cyclosporine, an immunosuppressive drug, is effective in the treatment of recalcitrant psoriasis. Previous work suggested that keratinocyte hyperproliferation and inflammation are linked in psoriasis and that immune mechanisms participate in the pathogenesis of psoriasis. Transforming growth factor (TGF) alpha may be an important regulatory factor of epidermal growth as overproduction of TGF-alpha is associated with epidermal hyperplasia in psoriatic plaques and epidermal growth factor receptors are overexpressed in psoriatic epithelium. In this study, the effects of cyclosporine on cultured human keratinocytes were examined. Cyclosporine specifically inhibited keratinocyte cell-cycle progression in the G1 phase without causing keratinocytes to terminally differentiate. Cyclosporine did not decrease the expression of TGF-alpha or epidermal growth factor receptors. These results suggest that the effects of cyclosporine on psoriatic skin are unrelated to direct effects on autocrine growth regulation of keratinocytes via TGF-alpha production or of epidermal growth factor receptor modulation.

Topics: Chemokine CXCL10; Chemokines, CXC; Cyclosporins; Cytokines; ErbB Receptors; G1 Phase; Humans; Keratinocytes; Psoriasis; Transcription, Genetic; Transforming Growth Factor alpha; Transglutaminases

Transforming growth factor-alpha (TGF-alpha) is thought to be the major autocrine factor controlling growth in epidermal cells. To explore further the role of TGF-alpha in epidermal growth and differentiation, we used a human keratin K14 promoter to target expression of rat TGF-alpha cDNA to the stratified squamous epithelia of transgenic mice. Unexpectedly, the only regions of epidermis especially responsive to TGF-alpha overexpression were those that were normally thick and where hair follicle density was typically low. This included most, if not all, body skin from 2-day- to 2-week-old mice, and ear, footpad, tail, and scrotum skin in adult mice. In these regions, excess TGF-alpha resulted in thicker epidermis and more stunted hair growth. Epidermal thickening was attributed both to cell hypertrophy and to a proportional increase in the number of basal, spinous, granular, and stratum corneum cells. During both postnatal development and epidermal differentiation, responsiveness to elevated TGF-alpha seemed to correlate with existing epidermal growth factor (EGF) receptor levels, and we saw no evidence for TGF-alpha-mediated control of EGF receptor (EGFR) expression. In adults, no squamous cell carcinomas were detected, but benign papillomas were common, developing primarily in regions of mechanical irritation or wounding. In addition, adult transgenic skin that was still both sensitive to TGF-alpha and subject to mild irritation displayed localized regions of leukocytic infiltration and granular layer loss, characteristics frequently seen in psoriasis in humans. These unusual regional and developmental effects of TGF-alpha suggest a natural role for the growth factor in (1) controlling epidermal thickness during development and differentiation, (2) involvement in papilloma formation, presumably in conjunction with TGF-beta, and (3) involvement in psoriasis, in conjunction with some as yet unidentified secondary stimulus stemming from mild mechanical irritation/bacterial infection.

Topics: Animals; Animals, Newborn; Blotting, Northern; Cell Differentiation; Cell Division; Cells, Cultured; Epidermis; ErbB Receptors; Humans; Keratins; Mice; Mice, Transgenic; Papilloma; Phenotype; Psoriasis; Transforming Growth Factor alpha; Wounds and Injuries

Topics: Cell Division; ErbB Receptors; Humans; Interleukin-6; Keratinocytes; Psoriasis; Skin Neoplasms; Transforming Growth Factor alpha

Transforming growth factor-alpha (TGF-alpha) is a potent mitogen for epithelial cells that is expressed at low levels in normal epidermis and overexpressed in psoriasis. Epidermal growth factor (EGF) has been shown to inhibit hair growth but stimulate the growth of sebaceous and sweat glands, suggesting a potential role for a member of the EGF/TGF-alpha family in the normal development and function of skin appendages as well as epidermis. The present work demonstrates TGF-alpha protein in eccrine ducts, and eccrine, sebaceous, and apocrine glands. The proliferative dermal hair bulb does not express TGF-alpha in contrast to the differentiated outer root sheath hair follicle epithelia. In addition, hyperproliferative skin diseases including bullous congenital ichthyosiform erythroderma, squamous cell carcinoma, and psoriasis show increased TGF-alpha expression. Thus, TGF-alpha may play a role in the morphogenesis and function of normal skin appendages and its overexpression is common in benign and malignant hyperproliferative skin diseases.

Topics: Blotting, Western; Carcinoma, Squamous Cell; Cell Differentiation; Cell Division; Humans; Immunoenzyme Techniques; Psoriasis; Skin; Skin Neoplasms; Transforming Growth Factor alpha

To elucidate the involvement of transforming growth factor-alpha (TGF-alpha) in the pathogenesis of psoriasis, we measured TGF-alpha levels in the extracts from six normal epidermis and four psoriatic involved epidermis samples by enzyme-linked sorbent assay using monoclonal antibody specific for TGF-alpha. The amount of TGF-alpha in the extracts of normal epidermis was 1.45 +/- 1.06 ng/g of wet tissue, while the amount in psoriatic involved epidermis was 6.71 +/- 0.75 ng/g of wet tissue. The TGF-alpha level in psoriatic involved epidermis was thus 4.62 fold higher than that of normal epidermis (P less than 0.001). TGF-alpha binds to epidermal growth factor receptors and functions as an autocrine growth factor for epidermal keratinocytes. Therefore, the increased levels of TGF-alpha may be involved in the induction or the maintenance of hyperproliferation of psoriatic epidermal keratinocytes.

Topics: Enzyme-Linked Immunosorbent Assay; Epidermis; Humans; Psoriasis; Transforming Growth Factor alpha