摘要:

AbstractMammalian cells do not live as isolated organisms, but are instead organized into complex, highly specialized tissue organs composed of a homogeneous or a mixed cell population. In order to maintain tissue homeostasis in physiological and pathophysiological conditions, intercellular communication is an absolute requirement. This review will summarize our current knowledge as to how an extracellular signal is transduced via a specific receptor to the interior of the cell and how this signal will induce special cell functions. Attention will be paid to the major signal transduction pathways known to be active in keratinocytes, namely the adenylate cyclase, guanylate cyclase, tyrosine kinase, and phospholipase C systems. Finally, examples will be given of how interactions between these signal tranduction pathways can take place and how ‘signal cross‐talk’ might regulate keratinocyte fun

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1992.tb00073.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractDistinct differences of proteins in the plasma membranes have been described in psoriatic keratinocytes as compared with normal epidermis. These changes are presumably involved in the pathogenesis of psoriasis. To identify and distinguish glycosylated proteins of the plasma membranes of keratinocytes, a method for mild preparation was developed that avoids the use of degrading or digestive enzymes. After cell lysis, three steps of centrifugation were performed, including the use of a sucrose step gradient. A fine‐vesicular membrane fraction was obtained. Using marker enzymes for cell compartments, no contamination of cell nuclei or mitochondria and only 0.4% of endoplasmic reticulum was detectable in the final membrane fraction. Based on this preparation, disc‐polyacrylamide‐gel electrophoresis, followed by Western blotting, were performed. Staining with five different lectins to visualize glycosylated proteins allowed 75 different membrane glycoproteins to be distinguished. The patterns of normal, transformed (HaCaT), foreskin and psoriatic keratinocytes after cell culture with one passage were compared. Up to six proteins per lectin staining were expressed differently in psoriatic as compared to normal keratinocytes. Psoriatic cells shared similarities with highly proliferative foreskin cells, but not with transformed HaCaT cells. Main alterations of glycosylation were detected in the fucose content. In conclusion, the method developed for isolation of plasma membranes allows selective and sensitive examination of plasma membranes of normal and pathological keratinocytes. The glycosylation patterns observed suggest that distinct membrane proteins may be involved in the pathogenesis of psor

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1992.tb00074.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn order to elucidate the role of keratinocytes (KCs) in the induction of contact sensitivity, we applied various contact sensitizers [2,4‐dinitrofluorobenzene (DNFB), urushiol, 3‐n‐pentadecyleatechol (PDC), 4‐ethoxymethylene‐2‐phenyloxazol‐5‐one (oxazolone)] and tolerizing compounds [2,4‐dinitrothiocyanobenzene (DNTB), 5‐methyl‐3‐n‐pentadecyl‐catechol (5‐Me‐PDC)]onto the earskin of non‐sensitized Balb/c mice. In addition, we applied croton oil as a non‐sensitizing, but stimulatory agent. Cytokine production was demonstrated by Northern blot hybridization of the total cellular RNA extracted from epidermal cells depleted by Langerhans cells and Thy 1+ dendritic cells using radiolabeled DNA probes encoding for the murine cytokines IL‐lα, ‐2, ‐3, ‐4, TNFα, IFNτ, GM‐CSF and G‐CSF. From all cytokines tested, TNFα and IL‐lα were markedly increased uponin vivostimulation with contact sensitizers and also after application of croton oil. Both light and electron microscopic immunostaining with a polyclonal and monoclonal antibody demonstrated the presence of TNFα in the epidermis. This staining was most pronounced in KCs of the suprabasal epidermis upon application of contact sensitizers or croton oil, but not with tolerizing analogues. Using a functional assay significantly more TNFα was found in the supenatants of KCs treatedin vitrowith DNFB or LPS than with DNTB. GM‐CSF was found in untreated epidermis as well as in stimulated cells. The results suggest that the sensitizing properties of contact sensitizers may partly be dependent on their ability to induce proinflammatory mediators. The induction and release of TNF7α and IL‐lα in KCs by contact sensitizers may play an important role in the early response to immunogenic or inflammatory signalsin vivo, whereby tol

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1992.tb00075.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1992.tb00076.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1992.tb00077.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1992.tb00078.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY