JAK/STAT pathway mediates leptin-induced Ⅰ collagen mRNA expression in human hepatic stellate cells
- 药学院－已发表论文 
目的研究瘦素对肝星状细胞(HSC)α1(Ⅰ)型胶原mRNA表达和蛋白合成的影响,探讨Janus激酶/信号传导及活化转录因子(JAK/STAT)信号传导通路在瘦素诱导的HSC胶原基因表达过程中的作用。方法采用RT-PCR法、ELISA法和Western blot法分别检测不同浓度的瘦素对人肝星状细胞株LX-2α1(Ⅰ)型胶原mRNA表达、蛋白合成以及JAK1、STAT3磷酸化状态的影响;采用Western blot法和RT-PCR法分别观察JAK1抑制剂AG490对瘦素诱导的JAK1磷酸化和α1(Ⅰ)型胶原mRNA表达的影响;采用Western blot法分别观察AG490、LX-2转染STAT3反义寡核苷酸(STAT3-ASON)对瘦素诱导的STAT3磷酸化状态的影响;应用RT-PCR法检测LX-2转染STAT3-ASON对瘦素诱导的α1(Ⅰ)型胶原mRNA表达的影响。结果瘦素增加LX-2α1(Ⅰ)型胶原mRNA表达和蛋白合成,呈剂量效应关系,当瘦素浓度为80μg·L-1时达到最大值;瘦素促进JAK1、STAT3磷酸化,呈时间效应关系;AG490完全阻断瘦素诱导的JAK1、STAT3磷酸化和α1(Ⅰ)型胶原mRNA的表达;LX-2转染STAT3-ASON阻断瘦素诱导的STAT3磷酸化和α1(Ⅰ)型胶原mRNA的表达。结论瘦素通过增加HSCα1(Ⅰ)型胶原mRNA表达和蛋白合成而在肝纤维化发生发展过程中发挥重要的作用,JAK/STAT信号传导通路参与并调节该过程,AG490和LX-2转染STAT3-ASON可有效阻滞此传导途径。在人HSC中,活化的JAK1和STAT3信号可作为肝纤维化治疗新的分子靶点。Aim To investigate the effects of leptin on α1(Ⅰ) collagen mRNA expression and protein production, and the roles of Janus kinase/signal transducers and activators transcription(JAK/STAT) signaling transduction pathway in increased α1(Ⅰ) collagen mRNA expression stimulated by leptin in activated hepatic stellate cells(HSCs).Methods Firstly, α1(Ⅰ) collagen mRNA expression and protein production as well as JAK1 and STAT3 phosphorylation induced by leptin at different doses in a human HSC cell line, LX-2 were determined by RT-PCR, ELISA, and Western-blot.Secondly, the effects of JAK1 inhibitor AG490 on JAK1 phosphorylation and α1(Ⅰ) collagen mRNA expression stimulated by leptin were detected by Western blot and RT-PCR. Thirdly, the roles of AG490 and transfection with STAT3 antisense oligonucleotide(STAT3-ASON) in STAT3 phosphorylation after leptin were detected by Western blot. Finally, the effect of transfection with STAT3-ASON on α1(Ⅰ) collagen mRNA expression after leptin was measured by RT-PCR.Results Leptin increased α1(Ⅰ) collagen mRNA expression and protein production in a dose-dependent manner in LX-2, reaching a maximal level at 80 μg·L-1 leptin. In addition, phosphorylation of JAK1 and STAT3 after leptin exhibited a time-dependent effect. Besides, JAK1 inhibitor AG490 completely blocked JAK1 and STAT3 phosphorylation and increased in α1(Ⅰ) collagen gene expression after leptin in LX-2. Transfection with STAT3-ASON blocked STAT3 phosphorylation and increased α1(Ⅰ) collagen mRNA by leptin in LX-2.Conclusion Leptin had a direct action on liver fibrogenesis by stimulating α1(Ⅰ) collagen mRNA expression and protein production in activated HSC, and JAK/STAT signaling transduction pathway was involved in the process. JAK1 inhibitor AG490 and transfection with STAT3-ASON blocked the transduction pathway effectively in LX-2. Leptin may be an important factor in the development of hepatic fibrosis. Activated JAK1 and STAT3 signaling in human HSC line provided a novel molecular target for therapeutic intervention of liver fibrosis.