钾离子通道KCNJ15通过调控Th17细胞增强表达IL17A参与乙型重型肝炎发生的机制研究

Hepatitis B virus widely spreads in China, which lead to high morbidity of severe hepatitis B (liver failure).The pathogenesis of HBV-induced acute-on-chronic liver failure (HBV-ACLF) remains largely unclear, and so far there is no specific treatment in clinic. Currently it is generally accepted that immune responses play a critical role in the development of HBV-ACLF, in which process the important effect of Th17 cell was preliminarily elucidated. However, the specific regulatory mechanism in Th17 cell immunity still needs further investigation. Our previous research by human whole genomic gene chip showed that the expression of KCNJ15, a potassium ion channel gene, was over-expressed in peripheral and hepatic infiltrating CD4+ T lymphocytes from patients with HBV-ACLF. Meanwhile, in vitro studies showed that high expression of KCNJ15 was closely correlated with calcium flux and IL17A secretion. According to our findings, we suppose that KCNJ15 might be an important participant in the immune pathogenesis of HBV-ACLF by regulating Th17 cell expressing IL17A. The study of KCNJ15 on regulation of Th17 cell immunity may contribute to illustrate the immunological mechanism of HBV-ACLF, which provides theoretical foundation for diagnosis and treatment of the disease.

我国是乙型肝炎病毒（HBV）的高流行地区，其所致的重型肝炎（肝衰竭）发病率高，由于其发病机制尚未得到充分阐明，临床缺乏针对性的有效治疗手段。HBV引起的机体免疫功能紊乱在乙型重型肝炎中发挥重要作用，Th17细胞是潜在的效应细胞之一，但其功能的具体调控过程仍有待深入研究。我们的前期研究通过对比乙型重型肝炎和轻中度慢性乙型肝炎患者的外周血单个核细胞（PBMC）基因表达谱发现，钾离子通道基因KCNJ15在乙型重型肝炎患者肝组织和外周血CD4+T细胞表达显著增高。该分子的高表达可诱导Jurkat细胞胞内Ca离子浓度增高及IL17A增强表达。据此我们提出KCNJ15分子可能通过调控Th17细胞表达IL17A参与乙型重型肝炎的免疫学发病机制。对于KCNJ15分子调控Th17细胞功能的研究有望从新的视角揭示该疾病的免疫学发病机制，并为其诊断与治疗新策略提供理论依据。

HBV引起的机体免疫功能紊乱在乙型重型肝炎中发挥重要作用，但其功能的具体调控过程仍有待深入研究。本课题前期研究发现钾离子通道基因KCNJ15在乙型重型肝炎患者外周血单个核细胞中高度表达，并可能通过促进T细胞分泌白介素17从而影响T细胞功能，参与乙型重型肝炎中免疫性肝损伤机制。本课题拟分别从乙型重型肝炎临床病例和体外细胞模型，对KCNJ15分子影响T细胞自噬、干扰素分泌的免疫学机制及关键转录调控分子机制展开研究，进而阐述其参与乙型重型肝炎疾病发生发展过程的具体作用。主要研究结果显示KCNJ15在重型乙型肝炎患者外周血CD4+T细胞及CD8+T细胞的表达水平显著高于轻中度乙型肝炎患者及健康对照；其在重型乙型肝炎肝组织中表达亦显著增高。同时，构建了慢病毒包装的KCNJ15真核表达载体，建立了稳定表达KCNJ15分子的Jurkat细胞系。将稳定表达KCNJ15的Jurkat细胞系及对照病毒感染Jurkat细胞系进行lncRNA及小RNA的二代测序检测。生物信息分析提示KCNJ15可能会通过调控I型干扰素生成基因的可变剪切，从而影响干扰素的释放。体外实验中，KCNJ15慢病毒分别感染Jurkat细胞系及人原代淋巴细胞后，细胞自噬受抑制，增殖水平及IFN-γ释放显著增高。主要研究结果显示KCNJ15在乙型重型肝炎患者外周血T细胞及肝组织中高表达；KCNJ15通过影响自噬促进T细胞增殖及IFN-γ释放。表明KCNJ15可能通过影响自噬调控T细胞功能及干扰素分泌，从而参与乙型重型肝炎肝损伤机制。本研究为进一步阐明乙型重型肝炎免疫学发病机制奠定基础。