磷脂酶Cε（PLCε）在皮肤真皮及表皮细胞中调控炎症细胞因子的机制研究

Phospholipase Cε (PLCε) is the phosphoinositide-specific PLC regulated by the ras proto-oncogene product Ras and Rap1. PLCε knockout (KO) mice are resistant to two-stage skin chemical carcinogenesis initiated by 7,12-dimethylbenz[a]anthracene and promoted by phorbol 12-myristate 13-acetate (PMA). However, PLCε is not involved in cell proliferation and differation. This suggests that PLCε may reduce tumor promotion and development through inflammatory responses. In PLCε KO mice, inflammations such as that induced by PMA, associated with tumorigenesis and the elicitation phase of allergic contact hypersensitivity are attenuated compared to wild-type mice. Conversely, overexpressions of PLCε in the epidermis result in the development of skin inflammation that has similar characteristics of psoriasis in human. All of the data show that PLCε plays an important role in the regulation of pro-inflammatory molecule expression in non-immune cells such as keratinocytes and fibroblasts. This serves to augment inflammation and most likely to promote tumorigenesis. Results suggest that PLCε could be a molecular target for therapies of inflammatory diseases and prevention of carcinogenesis. However, to develop the therapeutic methods to target PLCε, there are numerous problems that need to be solved. It is monumental to study the mechanisms of pro-inflammatory molecules expression in non-immune cells regulated by PLCε to develop therapeutic methods that can control inflammation and prevent cancer promotion.

磷脂酶Cε（PLCε）是Ras/Rap小G蛋白的效应因子。在DMBA/PMA皮肤癌诱导实验中发现PLCε基因敲除小鼠与对照组相比皮肤癌的发生与恶化明显受到了抑制，证明了PLCε直接或间接地抑制皮肤肿瘤的发生与发展。但PLCε并未影响到细胞的增值与分化。暗示了PLCε是间接的（炎症反应）参与到皮肤肿瘤的抑制。PMA诱发的皮肤炎症以及接触性皮炎模型实验中发现PLCεKO小鼠与对照组相比炎症抑制显著。其主要表现是在非免疫性细胞（如皮肤成纤维细胞，角质形成细胞）所诱导的炎症细胞因子的抑制。当PLCε在表皮过剩表达时能够诱发类似牛皮癣的慢性皮肤炎症。进一步证明了PLCε在炎症反应中的重要作用。但其机制尚未清楚。所以了解PLCε在炎症反应的尤其是如何调控炎症细胞因子的产生机制机理具有重要意义。通过对PLCε调控炎症细胞因子的机制研究为其可能作为新型抗炎症药及抗肿瘤药物分子靶点奠定基础。

磷脂酶Cε （Phospholipase Cε，PLCε），是Ras/Rap小G蛋白的效应因子，前期研究发现PLCε在成纤维细胞和角质形成细胞中大量表达，且参与调控炎性细胞因子的诱导，在皮肤炎症中发挥重要作用，但机制尚未清楚。本课题利用皮肤屏障功能的模型，体外细胞培养实验以及皮肤创伤愈合模型进一步探索PLCε在非免疫细胞中对炎症细胞因子的调控机制。在皮肤屏障破坏的模型中，我们发现PLCε促进皮肤屏障破坏后的重建过程，并推测IL-22，IL-24为PLCε的关键上游因子。体外细胞培养实验验证了IL-22可直接活化角质形成细胞PLCε，IL-24 经由JAK/STAT3信号传到通路直接活化成纤维细胞PLCε。皮肤创伤愈合模型中，PLCεKO小鼠创缘组织中炎症反应明显减轻。Col6a1，Col17a1胶原的沉积及MMP1，MMP8，MMP9，MMP13等基质金属蛋白酶的表达在PLCεKO小鼠中也明显受到抑制进而影响瘢痕形成。体外细胞培养实验进一步探究Th衍生因子IL-17与PLCε的关系，我们发现在成纤维细胞体系中，IL-17可诱导IL-6的产生，IL-6再活化PLCε诱导新的炎症细胞因子的调控机制。本课题揭示了PLCε在创伤愈合及屏障维护中的作用，确立了PLCε上下游关键分子，为PLCε作为皮肤创伤后缓解瘢痕形成，治疗皮肤屏障功能破坏等相关疾病的药物靶点奠定工作基础。