Meyer-Hoffert Ulf, Rogalski Christina, Seifert Stefanie, Schmeling Gero, Wingertszahn Jana, Proksch Ehrhardt, Wiedow Oliver
Department of Dermatology, University Kiel, Kiel, Germany.
Exp Dermatol. 2004 Apr;13(4):234-41. doi: 10.1111/j.0906-6705.2004.00159.x.
Human keratinocytes are known to express the protease-activated receptors, PAR-1 and PAR-2. Activation of PAR-1 results in increased proliferation, whereas PAR-2 activation results in decreased keratinocyte proliferation. Trypsin activates PAR-1 and in higher concentrations, PAR-2. The aim of this study was to evaluate the overall effect of trypsin on keratinocyte proliferation in a mouse in vivo and in vitro model. Daily topical application of 0.3-300 pmol trypsin/cm2 on hairless mouse skin induced dose-dependent epidermal hyperproliferation as determined by an increase in 5-bromo-2'-deoxyuridine incorporation of up to eight-fold in basal keratinocytes and an up to three-fold increase in keratinocyte layers. This was accompanied by an increased transepidermal water loss. These effects of trypsin were abolished by the addition of the trypsin inhibitor n-p-tosyl-l-lysine-chloromethyl ketone. Histological analysis revealed acanthosis, hypergranulosis, and spongiosis in the epidermis as well as vasodilatation and an inflammatory infiltrate in the upper dermis. In the murine keratinocyte cell line PAM-212 activation of PAR-1 with specific activating peptides resulted in a calcium influx and an increase of proliferation, whereas activation of PAR-2 caused a diminished proliferation. Incubation with trypsin, PAR-1-, and PAR-2-activating peptides induced cytokine-induced neutrophil chemoattractant (KC) mRNA expression as a marker for inflammation in PAM-212 in a dose-dependent manner. In conclusion, our results suggest that trypsin induces in vivo epidermal proliferation and inflammation. Proliferation seems not to be signaled by PAR activation, but PAR-2-induced KC chemokine expression may contribute in part to trypsin-induced inflammation.
已知人类角质形成细胞表达蛋白酶激活受体PAR-1和PAR-2。PAR-1的激活会导致增殖增加，而PAR-2的激活则会导致角质形成细胞增殖减少。胰蛋白酶可激活PAR-1，在较高浓度下还可激活PAR-2。本研究的目的是在小鼠体内和体外模型中评估胰蛋白酶对角质形成细胞增殖的总体影响。在无毛小鼠皮肤上每日局部应用0.3 - 300 pmol胰蛋白酶/cm²，可诱导剂量依赖性的表皮过度增殖，这通过基底角质形成细胞中5-溴-2'-脱氧尿苷掺入量增加高达八倍以及角质形成细胞层数增加高达三倍来确定。这伴随着经表皮水分流失增加。添加胰蛋白酶抑制剂n-对甲苯磺酰基-L-赖氨酸氯甲基酮可消除胰蛋白酶的这些作用。组织学分析显示表皮有棘层肥厚、颗粒层增厚和海绵形成，以及真皮上层血管扩张和炎症浸润。在鼠角质形成细胞系PAM-212中，用特异性激活肽激活PAR-1会导致钙内流和增殖增加，而激活PAR-2则导致增殖减少。用胰蛋白酶、PAR-1和PAR-2激活肽孵育以剂量依赖性方式诱导细胞因子诱导的中性粒细胞趋化因子（KC）mRNA表达，作为PAM-212中炎症的标志物。总之，我们的结果表明胰蛋白酶可诱导体内表皮增殖和炎症。增殖似乎不是由PAR激活介导的，但PAR-2诱导的KC趋化因子表达可能部分促成了胰蛋白酶诱导的炎症。
