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  • FAMILY  (16)
  • 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: 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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  • 3
    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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  • 4
    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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  • 5
    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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  • 6
    Keywords: EXPRESSION ; Germany ; human ; CDNA ; GENE ; GENES ; HYBRIDIZATION ; PROTEIN ; PROTEINS ; transcription ; FAMILY ; TRANSCRIPTION FACTOR ; primary ; DOMAIN ; BINDING ; MEMBER ; MEMBERS ; SEQUENCE ; SEQUENCES ; chromosome ; MOUSE ; TRANSCRIPTION FACTORS ; IDENTIFICATION ; IN-SITU ; AMPLIFICATION ; PROMOTER ; ELEMENTS ; HEAT-SHOCK ; DATABASE ; REGION ; FIBER ; REGIONS ; keratin ; isolation ; DOMAINS ; GENE DOMAIN ; FOLLICLE ; HAIR-FOLLICLES ; CLUSTER ; HUMAN TYPE-I ; PSEUDOGENES ; CALCIUM-BINDING PROTEIN ; HOXC13 ; cDNA,gene expression,hair follicle,in situ hybridization,keratin ; CYSTEINE-RICH PROTEINS ; HUMAN-CHROMOSOME 21
    Abstract: Analysis of the EBI/GeneBank database using nonhuman hair keratin associated protein (KAP) gene sequences as a query resulted in the identification of two human KAP gene domains on chromosome 21, one of which, located at 21q22.1, has recently been characterized. The second domain presented here, an approximately 90 kb domain on chromosome 21q23, harbored 16 KAP genes and two KAP pseudogenes. By comparison with known sheep and mouse KAP families, these genes could be assigned to two KAP families, KAP10 and KAP12, with the KAP10 family (12 members) being distinctly larger than the KAP12 family (four members). Systematic cDNA/3' rapid amplification of cDNA ends isolation studies using human scalp mRNA led to the identification of eight KAP10 and two KAP12 cDNA sequences. In situ hybridization analyses of human anagen hair follicles using specific 3'-noncoding sequences of the various KAP10/KAP12 genes revealed mRNA expression of nearly all KAP10 and KAP12 members exclusively in a narrow region of the middle portion of the hair fiber cuticle. Bioinformatic analyses of the promoter regions of the KAP10/KAP12 genes demonstrated several enhancer elements that were present in nearly all of the KAP genes. Primary among these were binding elements for the ETS, heat shock factor, AML, and HOX families of transcription factors
    Type of Publication: Journal article published
    PubMed ID: 14962103
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  • 7
    Keywords: ANGIOGENESIS ; CANCER ; EXPRESSION ; INVASION ; proliferation ; SURVIVAL ; tumor ; CELL-PROLIFERATION ; MICROVESSEL DENSITY ; DENSITY ; GENE ; GENES ; TUMORS ; PATIENT ; ACTIVATION ; FAMILY ; prognosis ; PROGRESSION ; MUTATION ; metastases ; MELANOMA ; MUTATIONS ; ONCOGENE ; CHILDREN ; CUTANEOUS MELANOMA ; INITIATION ; BRAF ; N-RAS ; Ras ; neuroblastoma ; RE ; PATIENT SURVIVAL ; cell proliferation ; CODON ; CUTANEOUS MELANOMAS ; Ki-67 ; NEVI ; RAS MUTATIONS ; VERTICAL GROWTH-PHASE
    Abstract: Previous studies have shown frequent mutations in the BRAF (V-raf murine sarcoma viral oncogene homolog B1) or NRAS ( neuroblastoma RAS viral [V-ras] oncogene homolog) genes in cutaneous melanoma, but the relationship between these alterations and tumor cell proliferation has not been examined in human melanoma. In our study of 51 primary nodular melanomas and 18 paired metastases, we found mutations in BRAF ( codon 600, previously denoted 599) in 15 primary tumors (29%) and eight metastases (44%). The figures for NRAS mutations were 27% and 22%, respectively. Mutations in BRAF and NRAS genes were mutually exclusive in all but one case, and were maintained from primary tumors through their metastases. Mutations, however, were not associated with tumor cell proliferation by Ki-67 expression, tumor thickness, microvessel density, or vascular invasion, and there were no differences in patient survival. Although BRAF and NRAS mutations are likely to be important for the initiation and maintenance of some melanomas, other factors might be more significant for proliferation and prognosis in subgroups of aggressive melanoma
    Type of Publication: Journal article published
    PubMed ID: 16098042
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  • 8
    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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  • 9
    Keywords: RECEPTOR ; CELLS ; EXPRESSION ; GROWTH ; GROWTH-FACTOR ; IN-VITRO ; INVASION ; tumor ; TUMOR-CELLS ; Germany ; VITRO ; SYSTEM ; SYSTEMS ; ENZYMES ; TISSUE ; MECHANISM ; FAMILY ; INDUCTION ; mechanisms ; fibroblasts ; ALPHA ; antibodies ; antibody ; PROGRESSION ; METASTASIS ; NUDE-MICE ; MELANOMA ; DEGRADATION ; ANTAGONIST ; HUMAN DERMAL FIBROBLASTS ; MATRIX ; TUMOR INVASION ; collagen ; MATRIX METALLOPROTEINASES ; MELANOMA-CELLS ; TUMORIGENICITY ; regulation ; interaction ; basic fibroblast growth factor ; bFGF ; dermal fibroblasts ; IL-1 alpha ; MALIGNANT MELANOMAS ; TIMP-1 ; TISSUE INHIBITOR
    Abstract: Tumor invasion and metastasis of melanoma have been shown to require proteolytic degradation of the extracellular environment, achieved primarily by enzymes of the matrix metalloproteinases (MMP) family. Increased enzyme activity is localized at the border of tumor cells and the adjacent peritumoral connective tissue, emphasizing the crucial role of tumor-stroma interactions in the regulation of MMP activity. To analyze whether direct cell-cell contacts of melanoma cells and stromal fibroblasts or whether soluble factors, secreted by melanoma cells are involved in the regulation of MMP, we used different in vitro co-culture systems. Both direct and indirect co-cultures of high invasive BLM melanoma cells and human dermal fibroblasts resulted in an induction of pro-MMP-1 synthesis. Medium conditioned by BLM cells strongly induced pro-MMP-1 synthesis in fibroblasts, indicating the importance of diffusible factors for this induction. Competition by recombinant human interleukin (IL)-1 receptor antagonist, neutralizing IL-1alpha and basic fibroblast growth factor (bFGF) antibodies, resulted in a concentration-dependent reduction of pro-MMP-1 synthesis. Taken together, our results indicate an essential role for soluble factors, mainly IL-1alpha and bFGF, in the stimulation of dermal fibroblasts by human melanoma cells to secrete MMP-1
    Type of Publication: Journal article published
    PubMed ID: 15737206
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  • 10
    Keywords: APOPTOSIS ; CELLS ; EXPRESSION ; GROWTH ; proliferation ; TUMOR-CELLS ; DIFFERENTIATION ; KERATINOCYTES ; fibroblasts ; CATALYTIC SUBUNIT GENE ; CELL- PROLIFERATION ; differentiation markers ; DIRECT ACTIVATION ; EPIDERMAL DIFFERENTIATION ; IMMORTAL CELLS ; organotypic cocultures ; STEM-CELLS ; telomerase
    Abstract: Formation of a well structured epidermis strictly depends on a tight balance between proliferation and differentiation. Accordingly, telomerase, which is restricted to proliferating cells, is downregulated with differentiation. It is unclear, however, whether this inhibition is essential to or only a consequence of the differentiation process. By studying different variants of the HaCaT skin keratinocytes we now show that constitutive overexpression of human telomerase reverse transcriptase (hTERT) in HaCaT-TERT cells (lacking its own differentiation-sensitive promoter) and constitutive expression of the c-myc gene in HaCaT-myc cells caused increased proliferation in conventional cultures; however, this proliferative advantage was not maintained in tissue-like organotypic cocultures. Despite reduced stratification, HaCaT- myc cells were still able to develop a fully differentiated epithelium. HaCaT-TERT cultures, on the other hand, expressed all markers of early but not of terminal differentiation. The failure to differentiate terminally was observed in hTERT mass cultures and individual clones and correlated with an intense nuclear hTERT staining of the uppermost cells of the HaCaT-TERT epithelia. Thus, our data suggest that constitutive overexpression of hTERT does not interfere with epidermal differentiation per se but blocks the terminal stage of differentiation and therefore indicates that hTERT/telomerase plays an active part in the regulatory pathway of epidermal differentiation
    Type of Publication: Journal article published
    PubMed ID: 12839571
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