School of Pharmacy, Nantong University, Nantong, Jiangsu, China.
School of Pharmacy, Nantong University, Nantong, Jiangsu, China.
Toxicol Lett. 2021 Oct 10;350:10-21. doi: 10.1016/j.toxlet.2021.06.018. Epub 2021 Jun 27.
Hepatocyte senescence is a core event that mediates the occurrence and development of alcoholic liver disease. Nuclear factor of activated T-cells 4 (NFATc4) is a key driver of nonalcoholic steatohepatitis. However, little was known about the implication of NFATc4 for alcoholic liver disease. This study was aimed to investigate the role of NFATc4 in hepatocyte senescence and further elucidate the underlying mechanism.
Real-time PCR, Western blot, immunofluorescence staining, and enzyme-linked immunosorbent assay were performed to explore the role of NFATc4 in hepatocyte senescence.
NFATc4 was induced in ethanol-incubated hepatocytes. NFATc4 knockdown recovered cell viability and reduced the release of aspartate transaminase, alanine transaminase, and lactic dehydrogenase from ethanol-incubated hepatocytes. NFATc4 knockdown protected mice from alcoholic liver injury and inflammation. NFATc4 knockdown counteracted ethanol-induced hepatocyte senescence, evidenced by decreased senescence-associated β-galactosidase positivity and reduced p16, p21, HMGA1, and γH2AX, which was validated in in vivo studies. Peroxisome proliferator-activated receptor (PPAR)γ was inhibited by NFATc4 in ethanol-treated hepatocytes. PPARγ deficiency abrogated the inhibitory effects of NFATc4 knockdown on hepatocyte senescence, oxidative stress, and hepatic steatosis in mice with alcoholic liver disease.
This work discovered that ethanol enhanced NFATc4 expression, which further triggered hepatocyte senescence via repression of PPARγ.
肝细胞衰老（Hepatocyte senescence）是介导酒精性肝病（Alcoholic liver disease）发生和发展的核心事件。激活 T 细胞的核因子 4（Nuclear factor of activated T-cells 4，NFATc4）是非酒精性脂肪性肝炎（Nonalcoholic steatohepatitis）的关键驱动因素。然而，NFATc4 对酒精性肝病的影响知之甚少。本研究旨在探讨 NFATc4 在肝细胞衰老中的作用，并进一步阐明其潜在机制。
采用实时 PCR、Western blot、免疫荧光染色和酶联免疫吸附试验（Enzyme-linked immunosorbent assay）来研究 NFATc4 在肝细胞衰老中的作用。
乙醇孵育的肝细胞中诱导了 NFATc4。NFATc4 敲低恢复了细胞活力，并降低了乙醇孵育的肝细胞中天门冬氨酸转氨酶（Aspartate transaminase）、丙氨酸转氨酶（Alanine transaminase）和乳酸脱氢酶（Lactic dehydrogenase）的释放。NFATc4 敲低可保护小鼠免受酒精性肝损伤和炎症。NFATc4 敲低可逆转乙醇诱导的肝细胞衰老，表现为衰老相关的β-半乳糖苷酶阳性细胞减少和 p16、p21、HMGA1 和 γH2AX 降低，这在体内研究中得到了验证。过氧化物酶体增殖物激活受体（Peroxisome proliferator-activated receptor，PPAR）γ 在乙醇处理的肝细胞中被 NFATc4 抑制。在酒精性肝病小鼠中，PPARγ 缺失消除了 NFATc4 敲低对肝细胞衰老、氧化应激和肝脂肪变性的抑制作用。
本研究发现乙醇增强了 NFATc4 的表达，进而通过抑制 PPARγ 触发了肝细胞衰老。
