Zhan Lei, Yang Yang, Ma Tao-Tao, Huang Cheng, Meng Xiao-Ming, Zhang Lei, Li Jun
The Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Medical University, Hefei, China.
Mol Cell Biochem. 2015 Apr;402(1-2):9-22. doi: 10.1007/s11010-014-2298-6. Epub 2015 Jan 20.
Hepatic stellate cell (HSC) activation is a significant event in the development of liver fibrosis. Promoting the activated HSCs apoptosis contributes to the reversal of liver fibrosis. Autophagy is considered to be critical for many cellular and pathological processes including liver fibrosis. Transient receptor potential vanilloid 4 (TRPV4), another member of the transient receptor potential (TRP) channel, is proved to be a vital modulator in regulating HSC proliferation during liver fibrosis. However, the precise mechanism of TRPV4 on HSC apoptosis is still unclear. Here, we explored the role of TRPV4 in regulating HSC-T6 cell apoptosis. Our study detected that the expressions of TRPV4 mRNA and protein were dramatically increased in HSC-T6 in response to TGF-β1 stimulation by qRT-PCR and Western blot. Moreover, the HSC-T6 transfected with si-TRPV4 increased apoptosis and inhibited autophagy. In addition, the HSC-T6 treated with 4α-phorbol 12,13-didecanoate results in suppression of apoptosis and increase of autophagy. Furthermore, we indicated that TRPV4 induces autophagy by regulating AKT signaling pathway. In addition, we found that blockade of autophagy by chemical antagonists chloroquine (CQ) leads to increased apoptosis. Furthermore, blocking autophagy by CQ did not lead to a distinct change with or without TRPV4 over-expression. These results indicated that TRPV4 could inhibit HSCs apoptosis partially by regulating autophagy-dependent AKT signaling pathway activation.
肝星状细胞（HSC）激活是肝纤维化发展过程中的一个重要事件。促进活化的肝星状细胞凋亡有助于肝纤维化的逆转。自噬被认为对包括肝纤维化在内的许多细胞和病理过程至关重要。瞬时受体电位香草酸受体4（TRPV4）是瞬时受体电位（TRP）通道的另一个成员，已被证明是肝纤维化过程中调节肝星状细胞增殖的重要调节因子。然而，TRPV4对肝星状细胞凋亡的确切机制仍不清楚。在此，我们探讨了TRPV4在调节肝星状细胞T6（HSC-T6）凋亡中的作用。我们的研究通过qRT-PCR和蛋白质印迹法检测到，在转化生长因子-β1（TGF-β1）刺激下，HSC-T6中TRPV4 mRNA和蛋白的表达显著增加。此外，用小干扰RNA（si-TRPV4）转染的HSC-T6细胞凋亡增加，自噬受到抑制。另外，用4α-佛波醇12,13-十四酸酯处理HSC-T6细胞会导致凋亡受到抑制，自噬增加。此外，我们表明TRPV4通过调节AKT信号通路诱导自噬。此外，我们发现用化学拮抗剂氯喹（CQ）阻断自噬会导致凋亡增加。此外，无论是否有TRPV4过表达，用CQ阻断自噬均未导致明显变化。这些结果表明，TRPV4可通过调节自噬依赖性AKT信号通路激活来部分抑制肝星状细胞凋亡。
