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1.
A lectin-binding glycoprotein of Mr 135,000 associated with basal keratinocytes in pig epidermis. 总被引:1,自引:0,他引:1
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Pig epidermis separated by 1 M-CaCl2 treatment was homogenized and separated into three fractions by filtration through nylon mesh and high-speed centrifugation. Lectin-binding glycoproteins were isolated from urea/deoxycholate/mercaptoethanol extracts of the residue fraction that resisted filtration, from deoxycholate extracts of the particulate material in the filtrate and from the soluble fraction. Concanavalin A, Ricinus communis (castor bean) agglutinin 1, peanut (Arachis hypogaea) agglutinin and Ulex europaeus (gorse) agglutinin-binding glycoproteins in the three epidermal fractions were analysed by SDS/polyacrylamide-gel electrophoresis. A major neuraminidase-sensitive glycoprotein component of the particulate fraction of Mr 135,000 was strongly bound by concanavalin A and Ricinus communis agglutinin 1, but only weakly by peanut and Ulex europaeus agglutinins. This glycoprotein was not detected in the residue or soluble fractions of the epidermis, indicating that it had only a limited distribution within the tissue. The 135,000-Mr glycoprotein was one of two major glycoprotein antigens in the particulate fraction. Rabbits immunized with total particulate glycoproteins produced antibodies directed mainly against 135,000- and 110,000-Mr components. Monospecific antibodies were obtained from guinea pigs immunized with the 135,000-Mr glycoprotein band excised from polyacrylamide gels. Indirect immunofluorescence with the use of affinity-purified antibodies showed that the 135,000-Mr glycoprotein was present at the surface of cells in the basal layer of the epidermis as well as at that of other stratified epithelia. It was not present on differentiating cells in the suprabasal layers of the epithelium, suggesting an important role in the attachment or proliferative functions of basal cells in stratified epithelia. Metabolic labelling studies with skin explants cultured in the presence of D-[3H]glucosamine showed that this basal-cell glycoprotein was synthesized by cultured tissue. The major D-[3H]glucosamine-labelled glycoprotein component in the residue and particulate fractions of cultured epidermis had an Mr of 135,000, was immunoprecipitated by rabbit antisera raised against particulate epidermal glycoproteins and was bound by concanavalin A. The labelling of this glycoprotein with D-[3H]glucosamine was sensitive to tunicamycin, indicating that the basal-cell glycoprotein contained N-glycosidically linked oligosaccharides. 相似文献
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Reichelt J 《European journal of cell biology》2007,86(11-12):807-816
The epidermis, like many other tissues, reacts to mechanical stress by increasing cell proliferation. Mechanically stressed skin regions often develop thicker skin and hyperkeratosis. Interestingly, a large number of skin diseases are accompanied by epidermal proliferation and hyperkeratosis even under normal mechanical stress conditions. Although, some of the molecular pathways of mechanical signaling involving integrins, the epidermal growth factor receptor and mitogen-activated protein kinases are known it is still unclear, how mechanical force is sensed and transformed into the molecular signals that induce cell proliferation. This review focuses on the molecules and pathways known to play a role in mechanotransduction in epidermal keratinocytes and discusses the pathways identified in other well-studied cell types. 相似文献
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Differentiation-associated expression of ceramidase isoforms in cultured keratinocytes and epidermis
Houben E Holleran WM Yaginuma T Mao C Obeid LM Rogiers V Takagi Y Elias PM Uchida Y 《Journal of lipid research》2006,47(5):1063-1070
Ceramides (Cers) accumulate within the interstices of the outermost epidermal layers, or stratum corneum (SC), where they represent critical components of the epidermal permeability barrier. Although the SC contains substantial sphingol, indicative of ceramidase (CDase) activity, which CDase isoforms are expressed in epidermis remains unresolved. We hypothesized here that CDase isoforms are expressed within specific epidermal compartments in relation to functions that localize to these layers. Keratinocytes/epidermis express all five known CDase isoforms, of which acidic and alkaline CDase activities increase significantly with differentiation, persisting into the SC. Conversely, neutral and phytoalkaline CDase activities predominate in proliferating keratinocytes. These differentiation-associated changes in isoform activity/protein are attributed to corresponding, differentiation-associated changes in mRNA levels (by quantitative RT-PCR). Although four of the five known CDase isoforms are widely expressed in cutaneous and extracutaneous tissues, alkaline CDase-1 occurs almost exclusively in epidermis. These results demonstrate large, differentiation-associated, and tissue-specific variations in the expression and activities of all five CDase isoforms. Because alkaline CDase-1 and acidic CDase are selectively upregulated in the differentiated epidermal compartment, they could regulate functions that localize to the distal epidermis, such as permeability barrier homeostasis and antimicrobial defense. 相似文献
5.
On the basis of the modern conceptions postulating that the growing layer of normal epidermis contains two populations of keratinocytes differing greatly in the rate of mitotic division (stem and transient cells), a hypothesis was proposed that explains the reason for the establishment of the portion of the proliferating fraction close to 60%. A relationship between this value and the distribution of keratinocytes of the basal layer in space was demonstrated, and formulae for its calculation were derived. Possible pathways of the transition from the normal spatial configuration to the distribution typical for the focal lesion in psoriasis were analyzed when all stem cells begin to divide vigorously, and the size of the population of transient cells is 100%. 相似文献
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Keratinocytes require abundant cholesterol for cutaneous permeability barrier function; hence, the regulation of cholesterol homeostasis is of great importance. ABCA1 is a membrane transporter responsible for cholesterol efflux and plays a pivotal role in regulating cellular cholesterol levels. We demonstrate that ABCA1 is expressed in cultured human keratinocytes (CHKs) and murine epidermis. Liver X receptor (LXR) activation markedly stimulates ABCA1 mRNA and protein levels in CHKs and mouse epidermis. In addition to LXR, activators of peroxisome proliferator-activated receptor (PPAR)alpha, PPARbeta/delta, and retinoid X receptor (RXR), but neither PPARgamma nor retinoic acid receptor, also increase ABCA1 expression in CHKs. Increases in cholesterol supply induced by LDL or mevalonate stimulate ABCA1 expression, whereas inhibiting cholesterol synthesis with statins or cholesterol sulfate decreases ABCA1 expression in CHKs. After acute permeability barrier disruption by either tape-stripping or acetone treatment, ABCA1 expression declines, and this attenuates cellular cholesterol efflux, making more cholesterol available for regeneration of the barrier. In addition, during fetal epidermal development, ABCA1 expression decreases at days 18-22 of gestation (term = 22 days), leaving more cholesterol available during the critical period of barrier formation. Together, our results show that ABCA1 is expressed in keratinocytes, where it is negatively regulated by a decrease in cellular cholesterol levels or altered permeability barrier requirements and positively regulated by activators of LXR, PPARs, and RXR or increases in cellular cholesterol levels. 相似文献
7.
Yan J. Jiang Biao Lu Elizabeth J. Tarling Peggy Kim M-Q. Man Debbie Crumrine Peter A. Edwards Peter M. Elias Kenneth R. Feingold 《Journal of lipid research》2010,51(11):3185-3195
ABCG1, a member of the ATP binding cassette superfamily, facilitates the efflux of cholesterol from cells to HDL. In this study, we demonstrate that ABCG1 is expressed in cultured human keratinocytes and murine epidermis, and induced during keratinocyte differentiation, with increased levels in the outer epidermis. ABCG1 is regulated by liver X receptor (LXR) and peroxisome proliferator-activated receptor-δ (PPAR-δ) activators, cellular sterol levels, and acute barrier disruption. Both LXR and PPAR-δ activators markedly stimulate ABCG1 expression in a dose- and time-dependent fashion. PPAR-γ activators also increase ABCG1 expression, but to a lesser degree. In contrast, activators of PPAR-α, retinoic acid receptor, retinoid X receptor, and vitamin D receptor do not alter ABCG1 expression. In response to increased intracellular sterol levels, ABCG1 expression increases, whereas inhibition of cholesterol biosynthesis decreases ABCG1 expression. In vivo, ABCG1 is stimulated 3–6 h after acute barrier disruption by either tape stripping or acetone treatment, an increase that can be inhibited by occlusion, suggesting a potential role of ABCG1 in permeability barrier homeostasis. Although Abcg1-null mice display normal epidermal permeability barrier function and gross morphology, abnormal lamellar body (LB) contents and secretion leading to impaired lamellar bilayer formation could be demonstrated by electron microscopy, indicating a potential role of ABCG1 in normal LB formation and secretion. 相似文献
8.
Interleukin 1 (IL-1), present in high amounts in normal human skin without any sign of inflammation, suggests a complex mechanism by which its bioactivity is regulated. The specific receptor antagonist of IL-1 (IL-1ra) was analyzed in human skin, sweat and cultured keratinocytes. Extracts of both skin and cultured keratinocytes blocked the binding of [125I]IL-1 to its receptor whereas sweat did not. The inhibitory activity was cell-associated, was not secreted by cultured keratinocytes, and IL-1ra mRNA was identified in these cells. There was an inverse relationship between the level of IL-1ra and that of IL-1 alpha and beta since extracts of differentiating keratinocytes (DK) and higher IL-1ra levels and expressed more mRNA for IL-1ra than non-differentiated keratinocytes (NDK), whereas NDK contained 4 times more IL-1 alpha and beta proteins than DK. This association of cell differentiation with a shift in agonist/antagonist ratio might be related to important autocrine or paracrine functions of IL-1 in normal and inflamed human skin. 相似文献
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M De Luca A T Franzi F D'Anna A Zicca E Albanese S Bondanza R Cancedda 《European journal of cell biology》1988,46(1):176-180
Human epidermal keratinocytes differentiate in vitro into a stratified epithelium suitable for grafting on burned patients. In this paper, we show that differentiated melanocytes are present in the cultured epithelium. In particular, we have found that i) melanocytes proliferate in the same culture conditions that allow keratinocyte growth, ii) during the culture the ratio between keratinocytes and melanocytes tends to remain constant, iii) melanocytes organize into the basal layer of the cultured epithelium independently of the presence of dermis, develop dendritic arborizations with melanosome-containing processes and transfer melanosomes into keratinocyte cytoplasm. 相似文献
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G Martinez M L Carnazza Marraro C Caltabiano 《Archivio italiano di anatomia e di embriologia》1990,95(1):65-76
A functioning epidermal melanin unit implies a melanocyte capable of transferring melanosomes to keratinocytes; this requires not only melanocytes with adequate dendrites but also "receptive" keratinocytes. Skin with incontinentia pigmenti was examined by electron microscopy. Premelanosomes were occasionally found within keratinocytes and deposits of extracellular granular material that came from vacuolar degeneration of keratinocytes adjacent to melanocytes. 相似文献
13.
Uncoupling proteins 1 and 3 are regulated differently 总被引:3,自引:0,他引:3
Using a heterologous yeast expression system, we have previously found a marked discordance between the effects of uncoupling protein (UCP) 1 and UCP3L on basal O(2) consumption in whole yeast versus isolated mitochondria. In whole yeast, UCP3L produces a greater stimulation of basal O(2) consumption, while in isolated mitochondria, UCP1 produces a much greater effect. As shown previously and in this report, UCP3L, in contrast to UCP1, is not inhibited by purine nucleotides. In the present study, we addressed two hypothetical mechanisms that could account for the observed discordance: (i) in whole yeast, purine nucleotides inhibit UCP1 but not UCP3L and (ii) preparations of isolated mitochondria lack an activator of UCP3L that is normally present in vivo. By use of a mutant of UCP1 that lacks purine nucleotide inhibition, it is demonstrated that cytosolic concentrations of purine nucleotides present in yeast effectively inhibit UCP1 activity. This suggests that the lower activity of UCP1 compared to UCP3L in whole yeast is due to purine nucleotide inhibition of UCP1 but not UCP3L. As potential activators of UCP3L we tested free fatty acids in whole yeast and isolated mitochondria. While UCP1 was strongly activated by free fatty acids, no stimulatory effect on UCP3L was observed. In summary, this study indicates that UCP1 and UCP3L differ in their regulation by purine nucleotides and free fatty acids. This different regulation may be related to different physiological functions of the two proteins. 相似文献
14.
Jans J Garinis GA Schul W van Oudenaren A Moorhouse M Smid M Sert YG van der Velde A Rijksen Y de Gruijl FR van der Spek PJ Yasui A Hoeijmakers JH Leenen PJ van der Horst GT 《Molecular and cellular biology》2006,26(22):8515-8526
Cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs) comprise major UV-induced photolesions. If left unrepaired, these lesions can induce mutations and skin cancer, which is facilitated by UV-induced immunosuppression. Yet the contribution of lesion and cell type specificity to the harmful biological effects of UV exposure remains currently unclear. Using a series of photolyase-transgenic mice to ubiquitously remove either CPDs or 6-4PPs from all cells in the mouse skin or selectively from basal keratinocytes, we show that the majority of UV-induced acute effects to require the presence of CPDs in basal keratinocytes in the mouse skin. At the fundamental level of gene expression, CPDs induce the expression of genes associated with repair and recombinational processing of DNA damage, as well as apoptosis and a response to stress. At the organismal level, photolyase-mediated removal of CPDs, but not 6-4PPs, from the genome of only basal keratinocytes substantially diminishes the incidence of skin tumors; however, it does not affect the UVB-mediated immunosuppression. Taken together, these findings reveal a differential role of basal keratinocytes in these processes, providing novel insights into the skin's acute and chronic responses to UV in a lesion- and cell-type-specific manner. 相似文献
15.
Human 8-oxoguanine-DNA glycosylase 1 (hOGG1) repairs 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) which results from oxidation of guanine. Reactive oxygen species (ROS) formed in response to ultraviolet (UV) radiation cause this DNA damage, which is involved in pathological processes such as carcinogenesis and aging. The initiation of skin tumors probably requires penetration of UV to the actively dividing basal layer of the epidermis in order for acute damage to become fixed as mutations. Previously, the majority of UVB fingerprint mutations have been found in the upper layers of human skin tumors, while UVA mutations have been found mostly in the lower layer. Our aim was to determine whether this localization of UVA-induced DNA damage is related to stratification of the repair-enzyme hOGG1. Anti-hOGG1 immunohistochemical staining of frozen sections of human foreskin, adult buttock skin, and reconstructed human skin samples showed the highest expression of hOGG1 in the superficial epidermal layer (stratum granulosum). Study of the hOGG1 mRNA expression again showed the highest level in the upper region of the epidermis. This was not regulated by UV irradiation but by the differentiation state of keratinocytes as calcium-induced differentiation increased hOGG1 gene expression. UVA-induced 8-oxo-dG was repaired more rapidly in the upper layer of human skin compared to the lower layers. Our results indicate that weaker expression of the nuclear form of hOGG1 enzyme in the basal cells of the epidermis may lead to a lack of DNA repair in these cells and therefore accumulation of UVA-induced oxidative DNA mutations. 相似文献
16.
Brandner JM Kief S Grund C Rendl M Houdek P Kuhn C Tschachler E Franke WW Moll I 《European journal of cell biology》2002,81(5):253-263
Occludin and several proteins of the claudin family have been identiried in simple epithelia and in endothelia as major and structure-determining transmembrane proteins clustered in the barrier-forming tight junctions (TJ), where they are associated with a variety of TJ plaque proteins, including protein ZO-1. To examine whether TJ also occur in the squamous stratified epithelium of the interfollicular human epidermis we have applied several microscopic and biochemical techniques. Using RT-PCR techniques, we have identiried mRNAs encoding protein ZO-1, occludin and claudins 1, 4, 7, 8, 11, 12, and 17 in both tissues, skin and cultured keratinocytes, whereas claudins i and 10 have only been detected in skin tissue. By immunocytochemistry we have localized claudin-1, occludin and protein ZO-1 in distinct plasma membrane structures representing cell-cell attachment zones. While claudin-1 occurs in plasma membranes of all living cell layers, protein ZO-1 is concentrated in or even restricted to the uppermost layers, and occludin is often detected only in the stratum granulosum. Using electron microscopy, typical TJ structures ("kissing points") as well as some other apparently related junctional structures have been detected in the stratum granulosum, interspersed between desmosomes. Modes and patterns of TJ formation have also been studied in experimental model systems, e.g., during wound healing and stratification as well as in keratinocyte cultures during Ca2+-induced stratification. We conclude that the epidermis contains in the stratum granulosum a continuous zonula occludens-equivalent structure with typical TJ morphology and molecular composition, characterized by colocalization of occludin, claudins and TJ plaque proteins. In addition, cell-cell contact structures and certain TJ proteins can also be detected in other epidermal cell layers in specific cell contacts. The pattern of formation and possible functions of epidermal TJ and related structures are discussed. 相似文献
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Arto Orpana Varpu Ranta Tomi Mikkola Lasse Viinikka Olavi Ylikorkala 《Journal of cellular biochemistry》1997,64(4):538-546
Both cell-matrix and cell-cell interactions are important regulators of the function of most human cells. In this study we investigated how these interactions controlled the production of vasodilators nitric oxide (NO), and prostacyclin (PGI2), in freshly isolated human umbilical vein endothelial cells (HUVECs). On the reconstituted extracellular matrix (ECM) Matrigel freshly isolated HUVECs treated with interleukin-1β, lipopolysaccharide, and interferon-γ, produced more NO, but less PGI2, than on gelatin substratum. High cell density was essential for inducibility of NO production in cells plated on gelatin substratum, but not on ECM. In cells plated on gelatin substratum at low cell density, which mimicked conventional HUVEC culturing conditions, both inducible NO production and the inducible NO synthase (iNOS) mRNA levels, detected by competitive RT-PCR, were low. However, inducible PGI2 production remained high in these cells. Highest inducible NO productions were observed in HUVECs that presumably had best maintained their original differentiated phenotype. Thus our data imply that the inducible NO and PGI2 productions of freshly isolated HUVECs were differently controlled by the extracellular matrix and cell density. Our data suggest that both cell-matrix and cell-cell interactions may have a strong influence on the proinflammatory cytokine responses of human vascular endothelial cells. J. Cell. Biochem. 64:538–546. © 1997 Wiley-Liss, Inc. 相似文献
19.
M. Catia Sorgato Alessandro Bertoli 《Biochemical and biophysical research communications》2009,379(2):171-546
It is now accepted that a conformational change of the cellular prion protein (PrPC) generates the prion, the infectious agent responsible for lethal neurodegenerative disorders, named transmissible spongiform encephalopathies, or prion diseases. The mechanisms of prion-associated neurodegeneration are still obscure, as is the cell role of PrPC, although increasing evidence attributes to PrPC important functions in cell survival. Such a behavioral dichotomy thus enables the prion protein to switch from a benign role under normal conditions, to the execution of neurons during disease. By reviewing data from models of prion disease and PrPC-null paradigms, which suggest a relation between the prion protein and Ca2+ homeostasis, here we discuss the possibility that Ca2+ is the factor behind the enigma of the pathophysiology of PrPC. Ca2+ features in almost all processes of cell signaling, and may thus tell us much about a protein that pivots between health and disease. 相似文献
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Summary A method for the selective separation of human epidermal cells, in which the Feulgen-stainable material suffers minimal damage, was investigated. The principal stage involves -chymotrypsin treatment of skin specimens as well as shaking in an isotonic solution. With respect to DNA distribution pattern, there was good agreement between that of epidermal cells separated with the microdissection-ultrasonic irradiation method, reported previously by us, and those separated by the present method. 相似文献