Fisher G J, Tavakkol A, Leach K, Burns D, Basta P, Loomis C, Griffiths C E, Cooper K D, Reynolds N J, Elder J T
Department of Dermatology, University of Michigan Medical School, Ann Arbor 48109.
J Invest Dermatol. 1993 Oct;101(4):553-9. doi: 10.1111/1523-1747.ep12365967.
Psoriatic lesions contain elevated levels of 1,2-diacylglycerol, the physiologic activator of protein kinase C (PKC), suggesting that PKC activation may be aberrant in psoriasis. We therefore have investigated the expression and properties of PKC isozymes in normal and psoriatic skin and in human skin cells. Chromatographic and immunoblot analyses revealed the presence of the calcium-dependent PKC isozymes PKC-alpha and -beta, but not -gamma, in normal human epidermis. PKC-beta was more prominent, constituting two thirds of the total calcium-dependent PKC activity. In psoriatic lesions, expression of both PKC-alpha and -beta was decreased, with preferential reduction (80%) of PKC-beta. Northern analysis and semi-quantitative polymerase chain reaction (PCR) indicated no change in the mRNA levels of PKC-alpha and -beta between normal and psoriatic epidermis. In normal epidermis, PKC-alpha was expressed mainly in the lower epidermis, whereas PKC-beta was localized to the upper cell layers, with very intense staining of CD1a+ Langerhans cells. In psoriasis, PKC-alpha staining was present in the lower epidermis, whereas PKC-beta staining was essentially absent, with the exception of some positive inflammatory cells. In addition to PKC-alpha and beta, immunoblot and Northern/PCR analysis revealed expression of four calcium-independent PKC isozymes, delta, epsilon, zeta, and eta, in both normal and psoriatic skin. There were no significant differences in mRNA levels among any of these PKC isozymes, between normal and psoriatic skin. Soluble PKC-zeta protein was modestly increased (twofold) in psoriatic, compared to normal, skin, whereas the levels of PKC-delta, epsilon, and eta were unchanged. Analysis of PKC isozyme expression in the three major cell types of human epidermis revealed that Langerhans cells and keratinocytes were the major sources of PKC-beta and PKC-zeta, respectively. These data demonstrate the diversity of PKC isozyme expression in human skin, and suggest that alterations of PKC-beta and -zeta may participate in the aberrant regulation of growth and differentiation observed in psoriasis.
银屑病皮损中1,2 -二酰甘油水平升高，1,2 -二酰甘油是蛋白激酶C（PKC）的生理性激活剂，提示PKC激活在银屑病中可能异常。因此，我们研究了PKC同工酶在正常皮肤和银屑病皮肤以及人皮肤细胞中的表达和特性。色谱分析和免疫印迹分析显示，正常人表皮中存在钙依赖性PKC同工酶PKC-α和-β，但不存在PKC-γ。PKC-β更为显著，占总钙依赖性PKC活性的三分之二。在银屑病皮损中，PKC-α和-β的表达均降低，其中PKC-β优先减少（80%）。Northern分析和半定量聚合酶链反应（PCR）表明，正常表皮和银屑病表皮之间PKC-α和-β的mRNA水平没有变化。在正常表皮中，PKC-α主要在下表皮表达，而PKC-β定位于上层细胞层，CD1a+朗格汉斯细胞染色非常强烈。在银屑病中，PKC-α染色存在于下表皮，而PKC-β染色基本不存在，除了一些阳性炎症细胞。除了PKC-α和-β，免疫印迹以及Northern/PCR分析显示，正常皮肤和银屑病皮肤中均表达四种钙非依赖性PKC同工酶，即δ、ε、ζ和η。在正常皮肤和银屑病皮肤之间，这些PKC同工酶的mRNA水平没有显著差异。与正常皮肤相比，银屑病皮肤中可溶性PKC-ζ蛋白适度增加（两倍），而PKC-δ、ε和η的水平没有变化。对人表皮三种主要细胞类型中PKC同工酶表达的分析表明，朗格汉斯细胞和角质形成细胞分别是PKC-β和PKC-ζ的主要来源。这些数据证明了人皮肤中PKC同工酶表达的多样性，并提示PKC-β和-ζ的改变可能参与了银屑病中观察到的生长和分化异常调节。
