Ultraviolet A-Induced Cathepsin K Expression Is Mediated via MAPK/AP-1 Pathway in Human Dermal Fibroblasts
Ultraviolet A-Induced Cathepsin K Expression Is Mediated via MAPK/AP-1 Pathway in Human Dermal Fibroblasts
复制标题
紫外线 A 诱导的组织蛋白酶 K 表达通过 MAPK/AP-1 途径介导人真皮成纤维细胞
DOI：
10.1371/journal.pone.0102732
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发表时间：
2014-07-21
期刊：
影响因子：
3.7
通讯作者：
Maibach, Howard I.
中科院分区：
文献类型：
--
作者：
Xu, Qingfang;Hou, Wei;Maibach, Howard I.
组织蛋白酶K（Cathepsin K，CatK）是一种半胱氨酸蛋白酶，具有很强的弹性蛋白分解活性，在人皮肤成纤维细胞（human dermal fibroblasts，HDF）的细胞内弹性蛋白降解中起主要作用，并与日光性弹性组织变性有关。在以前的研究中，CatK的表达在光老化的皮肤和成纤维细胞中下调，但在急性UVA照射的皮肤和成纤维细胞中上调。调节UVA诱导的CatK表达的潜在机制仍然难以捉摸。目的探讨长波紫外线（UVA）诱导人牙本质细胞（HDFs）CatK表达的调控机制。方法采用紫外线（UVA）照射原发性HDFs。使用相对细胞数的比色测定法分析细胞增殖。实时定量RT-PCR和Western blot检测10 J/cm 2 UVA照射后连续3天或UVA剂量增加处理的HDFs中CatK的表达。Western blot检测UVA激活的MAPK/AP-1通路。通过实时荧光定量RT-PCR和Western blot检测抑制MAPK通路和敲低Jun和Fos对UVA诱导的CatK表达的影响。结果UVA可显著增加细胞CatK mRNA和蛋白的表达，且呈剂量依赖性。UVA诱导的CatK表达沿着着JNK、p38和Jun的磷酸化，UVA增加Fos的表达。JNK和p38 MAPK通路的失活均显著降低UVA诱导的CatK表达，抑制JNK通路则抑制得更明显。此外，敲低Jun和Fos显着衰减基础和UVA诱导的CatK表达。结论UVA能增加HDFs中CatK的表达，最可能是通过激活MAPK通路和AP-1，这已被证明是基质金属蛋白酶的情况。由于目前选择抗光老化剂的策略集中在它们通过抑制UV活化的MAPK途径来降低MMPs表达的能力，因此未来的策略还应考虑它们对CatK表达的影响。
Background Cathepsin K (CatK), a cysteine protease with the potent elastolytic activity, plays a predominant role in intracellular elastin degradation in human dermal fibroblasts (HDFs), and contributes to solar elastosis. In previous studies, CatK expression was downregulated in photoaged skin and fibroblasts, but upregulated in acute UVA-irradiated skin and fibroblasts. The underlying mechanisms regulating UVA-induced CatK expression remain elusive. Objective This study investigates mechanisms involved in the regulation of UVA-induced CatK expression in HDFs. Methods Primary HDFs were exposed to UVA. Cell proliferation was analyzed using a colorimetric assay of relative cell number. Quantitative real-time RT-PCR and Western blot were performed to detect CatK expression in HDFs on three consecutive days after 10 J/cm2 UVA irradiation, or cells treated with increasing UVA doses. UVA-activated MAPK/AP-1 pathway was examined by Western blot. Effects of inhibition of MAPK pathway and knockdown of Jun and Fos on UVA-induced CatK expression were also measured by real-time RT-PCR and Western blot. Results UVA significantly increased CatK mRNA and protein expression in a dose-dependent manner. UVA-induced CatK expression occurred along with UVA-activated phosphorylation of JNK, p38 and Jun, UVA-increased expression of Fos. Inactivation of JNK and p38MAPK pathways both remarkably decreased UVA-induced CatK expression, which was suppressed more by inhibition of JNK pathway. Furthermore, knockdown of Jun and Fos significantly attenuated basal and UVA-induced CatK expression. Conclusion UVA is capable of increasing CatK expression in HDFs, most likely by activation of MAPK pathway and of AP-1, which has been shown to be the case for matrix metalloproteinases. As current strategies for selecting anti-photoaging agents focus on their ability to decrease MMPs' expression through inhibiting UV- activated MAPK pathway, future strategies should also consider their effect on CatK expression.