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  • DIFFERENTIATION  (19)
  • KERATINOCYTES  (16)
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  • 1
    Keywords: EXPRESSION ; IN-VITRO ; DISTINCT ; DIFFERENTIATION ; MESSENGER-RNA ; murine ; KERATINOCYTES ; EPIDERMAL DIFFERENTIATION ; ARACHIDONIC-ACID ; calcium gradient ; ENHANCING FACTOR ; epidermal barrier ; GROUP-II ; GROUP-V ; GROUP-X ; hyperproliferation ; INVITRO CULTIVATION ; LOW-MOLECULAR-WEIGHT ; neonatal mouse ; NEONATAL MOUSE KERATINOCYTES ; PERMEABILITY BARRIER HOMEOSTASIS ; epidermis
    Abstract: The action of secreted phospholipases A(2) in skin is thought to be essential for epidermal barrier homeostasis. The incomplete knowledge of presence and functions of the novel secreted phospholipase A(2) subtypes in skin prompted us to explore their expression in epidermis and primary keratinocytes from murine neonatal skin. We detected secreted phospholipases A(2) -IB, -IIA, -IIC, -IID, -IIE, -IIF, -V, -X, and -XII. To study secreted phospholipase A(2) expression during epidermal differentiation, primary keratinocytes from the basal, suprabasal, and upper differentiated layers of neonatal mouse epidermis were obtained by density gradient centrifugation. mRNA for secreted phospholipases A(2) -IB, -IIE, -IIF, -V, and -XII-1 are mainly expressed in the upper differentiated layers, whereas the most prominent enzymes in the basal and suprabasal layers are secreted phospholipases A(2) -IIA, -IID, and -X. The mRNA for secreted phospholipase A(2) -IIC was found in all fractions. Immunohistochemical analysis in mouse skin sections reflected the mRNA distribution patterns in the different epidermal cell fractions. After in vitro induction of keratinocyte differentiation by increasing the calcium concentration of the medium, secreted phospholipases A(2) -IB, -IIE, -IIF, -V, and -XII-1 were upregulated, whereas secreted phospholipases A(2) -IIA, -IIC, -IID, and -X were mainly expressed in proliferating keratinocytes. The specific secreted phospholipase A(2) expression profile in the skin suggests a distinct function for each enzyme in the epidermis
    Type of Publication: Journal article published
    PubMed ID: 12839576
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  • 2
    Keywords: APOPTOSIS ; CELLS ; EXPRESSION ; IN-VITRO ; INHIBITOR ; Germany ; human ; INHIBITION ; KINASE ; PATHWAYS ; VOLUME ; DEATH ; PROTEIN ; cell line ; DIFFERENTIATION ; ACCUMULATION ; RELEASE ; DNA ; REDUCTION ; INDUCTION ; SKIN ; FLOW ; protein kinase ; PROTEIN-KINASE ; treatment ; culture ; CELL-DEATH ; fragmentation ; DAMAGE ; CYTOCHROME-C ; lipids ; sebaceous gland ; SEBACEOUS GLANDS ; ARACHIDONIC-ACID ; OIL ; TERMINAL DIFFERENTIATION ; RETINOIC ACID ; retinoids ; 13-CIS-RETINOIC ACID ; BCL- 2 ; EPIDERMAL- KERATINOCYTES ; TRANS-RETINOIC ACID
    Abstract: Increased cell volume, accumulation of lipid droplets in the cytoplasm, and nuclear degeneration are phenomena indicating terminal differentiation of human sebocytes followed by holocrine secretion and cell death. The molecular pathways of natural and induced sebocyte elimination are still unknown, however. In this study, SZ95 sebocytes were found to exhibit DNA fragmentation after a 6 h culture followed by increased lactate dehydrogenase release after 24 h, indicating cell damage. With the help of morphologic studies and using Oil Red detection of cellular lipids, cell enlargement, accumulation of lipid droplets in the cytoplasm, and nuclear fragmentation could be observed under treatment with arachidonic acid. Staurosporine, a potent inhibitor of phospholipid Ca2+ - dependent protein kinase, increased externalized phosphatidylserine levels on SZ95 sebocytes, detected by annexin V/propidium iodide flow cytometry, as early as after 1 h, whereas dose-dependent reduction of bcl-2 mRNA and protein expression, enhanced DNA fragmentation, and increased caspase 3 levels, detected by caspase 3 inhibitor/propidium iodide flow cytometry, were found after 6 h of treatment. SZ95 sebocyte death was detected as early as after 6 h of SZ95 sebocyte treatment with high staurosporine concentrations (10(-6) -10(- 5) M). 5alpha-Dihydrotestosterone (10(-8) -10(-5) M) did not affect externalized phosphatidylserine levels and DNA fragmentation in SZ95 sebocytes but slightly decreased lactate dehydrogenase cell release. Neither acitretin nor 13-cis retinoic acid (10(-8) -10(-5) M) affected externalized phosphatidylserine levels, DNA fragmentation, and lactate dehydrogenase cell release, despite the increased caspase 3 levels under treatment with 13-cis retinoic acid. The combined staurosporine and 13-cis retinoic acid treatment enhanced DNA fragmentation in SZ95 sebocytes to the same magnitude as in cells only treated with staurosporine. In conclusion, SZ95 sebocytes in vitro undergo apoptosis, which can be enhanced by the terminal differentiation inductor arachidonic acid or by staurosporine and leads to cell death. 5alpha- Dihydrotestosterone inhibits SZ95 sebocyte death without involving apoptotic pathways, and retinoids did not affect the programmed death of human sebocytes. The latter result fits well with the currently reported inability of normal skin cells to undergo apoptosis after treatment with retinoids, in contrast to their malignant counterparts
    Type of Publication: Journal article published
    PubMed ID: 12542519
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  • 3
    Keywords: CELLS ; EXPRESSION ; IN-VITRO ; INHIBITOR ; proliferation ; CELL ; CELL-PROLIFERATION ; Germany ; human ; GENERATION ; SYSTEM ; DISTINCT ; PROTEIN ; PROTEINS ; cell line ; LINES ; ACTIVATION ; RESPONSES ; REDUCTION ; KERATINOCYTES ; SKIN ; CELL-LINES ; ISOFORM ; SUBUNIT ; Western-blot ; MEMBRANE ; CELL-LINE ; LINE ; CYTOCHROME-C ; EPITHELIAL-CELLS ; PROTEIN LEVELS ; western blot ; HaCaT ; MUCOSA ; HOST-DEFENSE ; DEFENSE ; human skin and oral epithelial cells,oxidoreductase,p67phox,spin trapping,superoxide radical ; NAD(P)H OXIDASE ; OXYGEN RADICALS ; P47(PHOX) ; SUPEROXIDE-PRODUCTION
    Abstract: In non-phagocytic cells, superoxide has been implicated in physiological and pathological cellular functions in the skin and mucosa, such as, host defense, mitogenic responses, and malignant conversion. Here, we identify a constitutively expressed heme-flavoprotein NADPH oxidase (Nox) system as a source of superoxide in human skin (HaCaT) and gingival mucosal (GM16) keratinocyte cell lines. Western blot analysis showed that both cell lines expressed the phagocyte oxidase (phox) cytosolic proteins Rac1, p40phox, and p67phox. With respect to the catalytic flavoheme protein subunit, HaCaT membranes, which expressed p22phox, showed an absorbance peak at 558 nm indicative of a b-type cytochrome. At mRNA levels, both GM16 and HaCaT cells expressed gp91phox homologs Nox1, Nox2, and Nox4, however, HaCaT cells expressed very low levels of Nox1 mRNA. At protein levels, Nox1 was readily detected in HaCaT but was nearly undetectable in GM16 cells. Consistently, Nox activity of HaCaT membranes was demonstrated by electron paramagnetic resonance spin-trapping and cytochrome c reduction, and the activity was sensitive to the flavoprotein inhibitor diphenylene iodonium. V-max values were 20-fold lower than those reported for phagocytic oxidase. In conclusion, keratinocytes expressed a Nox distinct from the phox isoform of phagocytes providing molecular evidence for a source of superoxide that may regulate cell proliferation and host defense in skin and oral mucosa
    Type of Publication: Journal article published
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  • 4
    Keywords: CELLS ; EXPRESSION ; tumor ; CELL ; Germany ; human ; PATHWAY ; GENE ; GENE-EXPRESSION ; GENES ; DIFFERENTIATION ; TUMORS ; COMPLEX ; COMPLEXES ; INDUCTION ; CONTRAST ; SKIN ; LOCALIZATION ; BENIGN ; keratin ; skin tumors ; epidermis ; FOLLICLE ; HAIR-FOLLICLES ; HUMAN TYPE-I ; MATRIX ; BETA-CATENIN EXPRESSION ; CORTEX ; HAIR FOLLICLE ; hair follicles,human,transcription factors,tumors ; HOXC13 ; INVOLUCRIN
    Abstract: Human hair follicles exhibit a complex pattern of sequential hair keratin expression in the hair matrix, cuticle, and cortex. In pilomatricomas, that is, benign skin tumors thought to arise from germinative matrix cells of the hair follicle and retaining morphological signs of cortical differentiation, this differential hair keratin pattern has been shown to be faithfully preserved in the lower and upper transitional cell compartments of the tumors. Here we show that also the co-expression of hair keratin hHa5 with its regulatory nuclear homeoprotein HOXC13 in matrix cells of the hair follicle is maintained in lower transitional cells of pilomatricomas. In contrast, the nuclear co-expression of LEF1 and beta-catenin, which in the hair follicle has been postulated to initiate cortex cell differentiation through the induction of hair keratin hHa1 expression (Merill et al, Genes Dev 15:1688-1705, 2001), is not preserved in upper transitional cells of pilomatricomas. Although these cells correctly express hHa1, they are completely devoid of LEF1 and nuclear LEF1/beta-catenin co-expression is shifted to a subpopulation of hair keratin-free basaloid cells of the tumors. These data imply that unlike the normal hair follicle, cortical differentiation in pilomatricomas is not under the control of the canonical Wnt signaling pathway
    Type of Publication: Journal article published
    PubMed ID: 15140206
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  • 5
    Keywords: RECEPTOR ; APOPTOSIS ; EXPRESSION ; IN-VITRO ; proliferation ; CELL ; Germany ; INHIBITION ; VITRO ; SYSTEM ; DEATH ; PROTEIN ; PROTEINS ; DRUG ; DIFFERENTIATION ; EPITHELIA ; ACTIVATION ; MARKER ; CONTRAST ; SKIN ; treatment ; ALPHA ; culture ; MATURATION ; CELL-DEATH ; ADHESION ; CELL-ADHESION ; RECEPTORS ; PROGRAMMED CELL-DEATH ; BARRIER FUNCTION ; TERMINAL DIFFERENTIATION ; AUTOIMMUNITY ; FUNCTIONAL-CHARACTERIZATION ; cell adhesion ; DRUGS ; ORGANOTYPIC COCULTURE ; cholinergic ; DARIERS-DISEASE ; KERATINOCYTE ADHESION ; NICOTINIC ACETYLCHOLINE-RECEPTOR ; PEMPHIGUS-VULGARIS
    Abstract: The aim of this study was to analyze the influence of cholinergic and anticholinergic drugs on epidermal physiology using organotypic cocultures (OTCs). Blocking of all acetylcholine receptors (AChRs) by combined treatment with mecamylamine and atropine or treatment with strychnine (blocking alpha 9nAChR) for 7-14 days resulted in a complete inhibition of epidermal differentiation and proliferation. Blockage of nicotinic (n) AChR with mecamylamine led to a less pronounced delay in epidermal differentiation and proliferation than blockage of muscarinic ( m) AChR with atropine, evidenced by reduced epithelial thickness and expression of terminal differentiation markers like cytokeratin 2e or filaggrin. In OTCs treated with atropine, mecamylamine, or strychnine, we could demonstrate intracellular lipid accumulation in the lower epidermal layers, indicating a severely disturbed epidermal barrier. In addition, we observed prominent acantholysis in the basal and lower suprabasal layers in mecamylamine-, atropine-, and strychnine-treated cultures, accompanied by a decreased expression of cell adhesion proteins. This globally reduced cell adhesion led to cell death via intrinsic activation of apoptosis. In contrast, stimulation of nAChR and mAChR with cholinergic drugs resulted in a significantly thickened epithelium, accompanied by an improved epithelial maturation. In summary, we show that epidermal AChR are crucially involved in the regulation of epidermal homeostasis
    Type of Publication: Journal article published
    PubMed ID: 16810300
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  • 6
    Keywords: EXPRESSION ; Germany ; PATHWAY ; COMMON ; COHORT ; EPIDEMIOLOGY ; GENE ; GENES ; DIFFERENTIATION ; PATIENT ; FAMILY ; DISORDER ; MOUSE ; IDENTIFICATION ; MUTATION ; MUTATIONS ; PHENOTYPE ; CHROMOSOMAL LOCALIZATION ; molecular epidemiology ; HETEROGENEITY ; DISORDERS ; FAMILIES ; USA ; GENOMIC STRUCTURE ; GENETIC-HETEROGENEITY ; EPIDERMIS-TYPE LIPOXYGENASES ; 12R-LIPOXYGENASE ; 12(R)-LIPOXYGENASE ALOX12B ; ERYTHRODERMA
    Abstract: In recent years several new genes for autosomal recessive congenital ichthyosis (ARCI) have been identified. However, little is known about the molecular epidemiology and pathophysiology of this genetically and clinically heterogeneous group of severe disorders of keratinization. ARCI is characterized by intense scaling of the whole integument often associated with erythema. We and others have shown that mutations in ALOX12B and ALOXE3, coding for the lipoxygenases 12R-LOX and eLOX-3 predominantly synthesized in the epidermis, can underlie this rare condition. Here we have surveyed a large group of 250 patients with ARCI for mutations in these two genes. We have identified 11 different previously unreported mutations in ALOX12B and ALOXE3 in 21 ARCI patients from 19 unrelated families and demonstrated that mutations in the two genes are the second most common cause for ARCI in this cohort of patients. Examination of the molecular data revealed allelic heterogeneity for ALOX12B and two mutational hotspots in ALOXE3. Functional analysis of all missense mutations and a splice site mutation demonstrated that complete loss of function of the enzymes underlies the phenotype. Our findings further establish the pivotal role of the 12-lipoxygenase pathway during epidermal differentiation. Journal of Investigative Dermatology (2009) 129, 1421-1428; doi:10.1038/jid.2008.409; published online 8 January 2009
    Type of Publication: Journal article published
    PubMed ID: 19131948
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  • 7
    Keywords: CELLS ; ACTIVATION ; KERATINOCYTES ; SKIN ; CYCLE ; MIGRATION ; E6 ; E-cadherin ; EPIDERMODYSPLASIA-VERRUCIFORMIS ; LIFE ; DNA LOADS
    Abstract: Human papillomaviruses (HPVs), which are contained in the alpha, beta, gamma, mu, and nu genera, differ in their oncogenic potential and their tropism for cutaneous or mucosal epidermis. Langerhans cells (LC), the only epidermal professional antigen-presenting cells, are readily detected in normal mucosal and cutaneous epithelium. The aim of this study is to determine whether LC loss, which has been reported for HPV16, occurs in other HPV genera and establish its significance in viral pathology. We found that, as for HPV16, LCs were reduced in lesions infected with high-risk mucosal (alpha 7 and alpha 9 species) and low-risk cutaneous (gamma and mu) types. Lesions infected with alpha 10 low-risk genital types had reduced LC but contained epidermal LC patches, coincident with dermis-localized regulatory T cells (T-regs). In contrast to other genera, LCs were common in the epidermis, and T-regs occupied the dermis of the potentially high-risk cutaneous beta-HPV type infected lesions. Therefore, LC loss in the infected lesions occurred irrespective of tropism or oncogenic potential of the HPV type. LC depletion in the HPV-infected epidermis may create an environment that is permissive for viral persistence and in HPV lesions in which LCs are found, the presence of typically immunosuppressive T-regs may compensate for their continued presence
    Type of Publication: Journal article published
    PubMed ID: 19759549
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  • 8
    Keywords: CELLS ; EXPRESSION ; Germany ; human ; CLONING ; GENE ; GENES ; HYBRIDIZATION ; DIFFERENTIATION ; DOMAIN ; IN-SITU ; PATTERNS ; gene expression ; cytoskeleton ; intermediate filaments ; keratin ; LAYER ; CELLS FLUGELZELLEN ; CUTICLE CELLS ; CYTOKERATINS ; GENE DOMAIN ; human hair follicle ; HUXLEY ; MAMMALIAN-TISSUES
    Abstract: In this study we report on the cloning of two novel human type II keratin cDNAs, K6irs3 and K6irs4, which were specifically expressed in the inner root sheath of the hair follicle. Together with the genes of two previously described type II inner root sheath keratins, K6irs1 and K6irs2, the K6irs3 and K6irs4 genes were subclustered in the type II keratin/hair keratin gene domain on chromosome 12q13. Evolutionary tree analysis using all known type II epithelial and hair keratins revealed that the K6irs1-4 formed a branch separate from the other epithelial and hair keratins. RNA in situ hybridization and indirect immunofluorescence studies of human hair follicles, which also included the K6irs2 keratin, demonstrated that both K6irs2 and K6irs3 were specifically expressed in the inner root sheath cuticle, but showed a different onset of expression in this compartment. Whereas the K6irs3 expression began in the lowermost bulb region, that of K6irs2 was delayed up to the height of the apex of the dermal papilla. In contrast, the K6irs4 keratin was specifically expressed in the Huxley layer. Moreover, K6irs4 was ideally suited to further investigate the occurrence of Flugelzellen, i.e., Huxley cells, characterized by horizontal cell extensions that pass through the Henle layer, abut upon the companion layer, and form desmosomal connections with the surrounding cells. Previously, we detected Flugelzellen only in the region along the differentiated Henle layer. Using the Huxley-cell-specific K6irs4 antiserum, we now demonstrate this cell type to be clearly apposed to the entire Henle layer. We provide evidence that Flugelzellen penetrate the Henle layer actively and may play a role in conferring plasticity and resilience to the otherwise rigid upper Henle layer
    Type of Publication: Journal article published
    PubMed ID: 12648212
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  • 9
    Keywords: EXPRESSION ; AGENTS ; human ; GENE ; PROTEIN ; DIFFERENTIATION ; TISSUE ; MICE ; MECHANISM ; INDUCTION ; TISSUES ; KERATINOCYTES ; mechanisms ; SKIN ; SEQUENCE ; SEQUENCES ; STAGE ; TRANSGENIC MICE ; IDENTIFICATION ; PROMOTER ; transgenic ; REGION ; FRANCE ; hyperproliferation ; epidermis ; TERMINAL DIFFERENTIATION ; LAYER ; MAMMALIAN-TISSUES ; HASSALLS CORPUSCLES ; FOLLICLE ; HAIR-FOLLICLES ; HUMAN TISSUES ; INNER-ROOT-SHEATH ; AGENT ; PATTERN ; HAIR FOLLICLE ; corneodesmosin ; CORNIFIED EPITHELIA ; GENE PROMOTER ; hyperkeratosis ; KERATINOCYTE DIFFERENTIATION ; promoter regions ; PSORIASIS SUSCEPTIBILITY ; REPORTER GENE ; S GENE ; STRATUM-CORNEUM
    Abstract: Corneodesmosin (CDSN) is a desmosomal protein expressed in the epidermis during the late stages of differentiation and in the inner root sheath of hair follicles. The homophilic adhesive properties of the protein suggest that it reinforces keratinocyte cohesion in the upper layers of the epidermis (stratum granulosum and stratum corneum). In this study, we analyzed the expression of the CDSN gene in 16 human tissues. We confirmed the closely restricted expression pattern of CSDN. Indeed, apart from the skin, the mRNA was significantly detected only in the placenta and the thymus. As a step in elucidating the mechanisms of tissue-specific expression, transgenic mice bearing a 4.2 kb fragment of the human CSDN gene promoter linked to the LacZ gene were generated. The reporter-gene expression was detected in special areas of the inner root sheath of the hair follicles and the hair medulla but not in the epidermis. Induction of epidermis hyperproliferation however either by pharmacological agents or by wounding led to strong expression of the reporter gene in the keratinocytes of the stratum granulosum and the parakeratotic corneocytes of the stratum corneum. The data suggest that the genomic sequences and/or regulating factors responsible for the cell-specific expression of the human CDSN gene in the normal hair follicle as well as in the hyperproliferative epidermis are different from those necessary for expression in the normal epidermis
    Type of Publication: Journal article published
    PubMed ID: 15086560
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  • 10
    Keywords: EXPRESSION ; COMBINATION ; GENE ; PROTEIN ; PROTEINS ; DIFFERENTIATION ; COMPLEX ; COMPLEXES ; FAMILY ; DOMAIN ; chromosome ; ACID ; intermediate filaments ; INTERMEDIATE-FILAMENTS ; CALCIUM ; epidermis ; CORNIFIED CELL-ENVELOPE ; BARRIER FUNCTION ; TERMINAL DIFFERENTIATION ; HUMAN SKIN ; intermediate filament ; keratinocyte ; HAIR FOLLICLE ; AMINO-ACID ; hair ; GENE FAMILY ; SWITZERLAND ; STRUCTURAL PROTEINS ; ENVELOPE ; fused gene ; HUMAN-CHROMOSOME 1Q21 ; KERATINOCYTE TRANSGLUTAMINASE ; LORICRIN ; lq21 ; PROFILAGGRIN ; repetin
    Abstract: The human repetin gene is a member of the "fused" gene family and localized in the epidermal differentiation complex on chromosome 1q21. The "fused" gene family comprises profilaggrin, trichohyalin, repetin, hornerin, the profilaggrin-related protein and a protein encoded by c1orf10. Functionally, these proteins are associated with keratin intermediate filaments and partially crosslinked to the cell envelope (CE). Here, we report the isolation and characterization of the human repetin gene and of its protein product. The repetin protein of 784 amino acids contains EF (a structure resembling the E helix-calcium-binding loop-F helix domain of parvalbumin) hands of the S100 type and internal tandem repeats typical for CE precursor proteins, a combination which is characteristic for "fused" proteins. Repetin expression is scattered in the normal epidermis but strong in the acrosyringium, the inner hair root sheat and in the filiform papilli of the tongue. Ultrastructurally, repetin is a component of cytoplasmic non-membrane "keratohyalin" F-granules in the stratum granulosum of normal epidermis, similar to profilaggrin. Finally, we show that EF hands are functional and reversibly bind Ca2+. Our results indicate that repetin is indeed a member of the fused gene family similar to the prototypical members profilaggrin and trichohyalin
    Type of Publication: Journal article published
    PubMed ID: 15854042
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