IL-1α介导的肝细胞衰老分泌表型在药物性肝损伤中对细胞再生的调控作用及机制研究

Senescence is the state of a stable growth arrest that restrict the replication of damaged and old cells. Recently, the senescent cells could secret the suite of pro-inflammatory cytokines (referred to as the senescence-associated secretory phenotype, SASP), which can influence the cell microenvironment and induces neighbor cells to undergo senescence(termed paracrine senescence). Latest studies indicate that SASP activation could participate in the pathophysiological mechanism of multiple organ injury and repair, furthermore may affect the course and prognosis of the disease. In addition, there are some studies demonstrated that IL-1α could act as an upstream regulator of SASP. Our previous study indicates that the cytokines of SASP are increased and have some kind of association with hepatocytes regeneration during acute DILI. However, the precise mechanisms of which, remain unknown. Therefore, it is speculated that IL-1α could regulate SASP activation，then has detrimental effects on the hepatocytes regeneration，therefore influences the prognosis of acute DILI. Wild type, IL-1α gene knockout mice will be used for drug-induced liver injury and senescence mouse model, at the same time macrophage adoptive transfer experiments and ex vivo experiments would be adopted into the study to explore the association among cellular senescence, SASP activation, and cell regeneration. Furthermore, it would be clarified that the mechanisms of IL-1α induces paracrine senescence through SASP by NF-κB pathway to reduce the regenerative response of hepatocytes in drug-induced liver injury.

衰老是一种稳定的生长阻滞状态，近年研究发现衰老细胞通过分泌细胞衰老相关分泌表型（SASP）因子，影响细胞微环境，促进周围正常的肝细胞发生衰老。最新研究发现SASP活化参与多种器官损伤修复的病理生理机制，影响疾病病程转归及预后。且有研究报道IL-1α作为SASP的上游调控因子调节SASP表达。我们前期研究发现在急性DILI小鼠模型中，SASP相关因子表达增加且与损伤后细胞增生存在某种关联性，但确切机制尚未完全明了。据此，我们推测IL-1α可能通过NF-κB，调节SASP活化表达，减弱肝细胞的增生，从而影响DILI进程及转归。本课题拟通过野生型、IL-1α基因敲除小鼠诱导DILI模型和衰老模型、及巨噬细胞过继实验，并结合体外实验了解细胞衰老、SASP活化表达和细胞增生之间的关联性，进一步阐明IL-1α通过NF-κB增强SASP活化促进肝细胞衰老扩散，抑制肝细胞的再生修复的作用及相关机制。

APAP诱导的肝损伤中，伴随ROS和炎性细胞因子的表达增加，衰老及SASP的表达也明显上调。本研究发现APAP造模小鼠肝内衰老相关标志物p16、p21表达较对照组明显升高。同时，肝内增生标志物Ki67及PCNA在肝细胞坏死区域很少有表达，仅在坏死区域外围有所表达。提示细胞衰老在急性肝损后后细胞再生及发挥负性调控作用。同时本研究中发现在APAP介导急性肝损伤的小鼠肝内伴随衰老相关标志物p16、p21蛋白表达增加，p-NF-κB及p-IκBα表达也有所上调。综上，本研究结表明，APAP在肝脏代谢消耗大量谷胱甘肽而引起ROS表达增加，导致胞内染色质片段漏出活化下游NF-κB通路，促进SASP相关细胞因子表达增加及衰老，影响肝细胞再生修复。