involucrin and Dermatitis

Topics: Animals; Apoptosis; CD8-Positive T-Lymphocytes; Dermatitis; Graft vs Host Disease; Keratinocytes; Mice; Mice, Inbred C57BL; Ovalbumin; Protein Precursors

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

Nuclear receptor-mediated signaling via RARs and PPARδ is involved in the regulation of skin homeostasis. Moreover, activation of both RAR and PPARδ was shown to alter skin inflammation. Endogenous all-trans retinoic acid (ATRA) can activate both receptors depending on specific transport proteins: Fabp5 initiates PPARδ signaling whereas Crabp2 promotes RAR signaling. Repetitive topical applications of ovalbumin (OVA) in combination with intraperitoneal injections of OVA or only intraperitoneal OVA applications were used to induce allergic dermatitis. In our mouse model, expression of IL-4, and Hbegf increased whereas expression of involucrin, Abca12 and Spink5 decreased in inflamed skin, demonstrating altered immune response and epidermal barrier homeostasis. Comprehensive gene expression analysis showed alterations of the cutaneous retinoid metabolism and retinoid-mediated signaling in allergic skin immune response. Notably, ATRA synthesis was increased as indicated by the elevated expression of retinaldehyde dehydrogenases and increased levels of ATRA. Consequently, the expression pattern of genes downstream to RAR was altered. Furthermore, the increased ratio of Fabp5 vs. Crabp2 may indicate an up-regulation of the PPARδ pathway in allergen-induced dermatitis in addition to the altered RAR signaling. Thus, our findings suggest that ATRA levels, RAR-mediated signaling and signaling involved in PPARδ pathways are mainly increased in allergen-induced dermatitis and may contribute to the development and/or maintenance of allergic skin diseases.

Topics: Allergens; Animals; ATP-Binding Cassette Transporters; Dermatitis; Fatty Acid-Binding Proteins; Female; Gene Expression Regulation; Heparin-binding EGF-like Growth Factor; Intercellular Signaling Peptides and Proteins; Interleukin-4; Mice; Mice, Inbred BALB C; Neoplasm Proteins; Ovalbumin; PPAR delta; Protein Precursors; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Serine Peptidase Inhibitor Kazal-Type 5; Serpins; Signal Transduction; Tretinoin

The epidermis is a stratified tissue composed of different keratinocyte layers that create a barrier protecting the body from external influences, pathogens, and dehydration. The barrier function is mainly achieved by its outermost layer, the stratum corneum. To create a mouse model to study pathophysiological processes in the outermost layers of the epidermis in vivo and in vitro we prepared a construct containing red fluorescent td-Tomato reporter sequence under the control of involucrin promoter and its first intron. Transgenic mice were generated by pronuclear injection and the expression and regulation of the transgene was determined by in vivo imaging and fluorescent microscopy. The promoter targeted the transgene efficiently and specifically into the outermost epidermal layers although weak expression was also found in epithelia of tongue and bladder. The regulation of expression in the epidermis, i.e. fluorescence intensity of the reporter, could be easily followed during wound healing and dermatitis. Thus, these transgenic mice carrying the tdTomato reporter could be used as a valuable tool to study impact of various genes dysregulating the epidermal barrier and to follow effects of therapeutic agents for treatment of skin diseases in vivo.

Topics: Animals; Cell Differentiation; Dermatitis; Epidermis; Epithelium; Gene Expression Regulation; Gene Targeting; Genes, Reporter; Immunohistochemistry; Introns; Luminescent Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Fluorescence; Promoter Regions, Genetic; Protein Precursors; Red Fluorescent Protein; Solanum lycopersicum; Tongue; Transgenes; Wound Healing

The barrier function of the skin protects the mammalian body against infection, dehydration, UV irradiation and temperature fluctuation. Barrier function is reduced with the skin's intrinsic aging process, however the molecular mechanisms involved are unknown. We previously demonstrated that Claudin (Cldn)-containing tight junctions (TJs) are essential in the development of the epidermis and that transgenic mice overexpressing Cldn6 in the suprabasal layers of the epidermis undergo a perturbed terminal differentiation program characterized in part by reduced barrier function. To dissect further the mechanisms by which Cldn6 acts during epithelial differentiation, we overexpressed a Cldn6 cytoplasmic tail deletion mutant in the suprabasal compartment of the transgenic mouse epidermis. Although there were no gross phenotypic abnormalities at birth, subtle epidermal anomalies were present that disappeared by one month of age, indicative of a robust injury response. However, with aging, epidermal changes with eventual chronic dermatitis appeared with a concomitant barrier dysfunction manifested in increased trans-epidermal water loss. Immunohistochemical analysis revealed aberrant suprabasal Cldn localization with marked down-regulation of Cldn1. Both the proliferative and terminal differentiation compartments were perturbed as evidenced by mislocalization of multiple epidermal markers. These results suggest that the normally robust injury response mechanism of the epidermis is lost in the aging Involucrin-Cldn6-CDelta196 transgenic epidermis, and provide a model for evaluation of aging-related skin changes.

Topics: Aging; Amino Acid Sequence; Animals; Cell Differentiation; Cell Proliferation; Claudins; Cytoplasm; Dermatitis; Down-Regulation; Epidermis; Gene Deletion; Immunohistochemistry; Membrane Proteins; Mice; Mice, Transgenic; Molecular Sequence Data; Mutation; Protein Precursors; Transgenes

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