Although the detrimental effects of diabetes mellitus/hyperglycemia have been observed in many liver disease models, the function and mechanism of hyperglycemia regulating liver-resident macrophages, Kupffer cells (KCs), in thioacetamide (TAA)-induced liver injury remain largely unknown. In this study, we evaluated the role of hyperglycemia in regulating NOD-like receptor family pyrin domain-containing 3 protein (NLRP3) inflammasome activation by inhibiting autophagy induction in KCs in the TAA-induced liver injury model. Type I diabetes/hyperglycemia was induced by streptozotocin treatment. Compared with the control group, hyperglycemic mice exhibited a significant increase in intrahepatic inflammation and liver injury. Enhanced NLRP3 inflammasome activation was detected in KCs from hyperglycemic mice, as shown by increased gene induction and protein levels of NLRP3, cleaved caspase-1, apoptosis-associated speck-like protein containing a caspase recruitment domain and interleukin-1β, compared with control mice. NLRP3 inhibition by its antagonist CY-09 effectively suppressed inflammasome activation in KCs and attenuated liver injury in hyperglycemic mice. Furthermore, inhibited autophagy activation was revealed by transmission electron microscope detection, decreased LC3B protein expression and p-62 protein degradation in KCs isolated from TAA-stressed hyperglycemic mice. Interestingly, inhibited 5' AMP-activated protein kinase (AMPK) but enhanced mammalian target of rapamycin (mTOR) activation was found in KCs from TAA-stressed hyperglycemic mice. AMPK activation by its agonist 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or mTOR signaling knockdown by small interfering RNA restored autophagy activation, and subsequently, inhibited NLRP3 inflammasome activation in KCs, leading to ultimately reduced TAA-induced liver injury in the hyperglycemic mice. Our findings demonstrated that hyperglycemia aggravated TAA-induced acute liver injury by promoting liver-resident macrophage NLRP3 inflammasome activation via inhibiting AMPK/mTOR-mediated autophagy. This study provided a novel target for prevention of toxin-induced acute liver injury under hyperglycemia.

中文翻译：

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高血糖症通过抑制AMPK / mTOR介导的自噬诱导促进肝驻留巨噬细胞NLRP3炎性小体活化，从而加剧了急性肝损伤。

尽管在许多肝脏疾病模型中都观察到了糖尿病/高血糖的有害影响，但在硫代乙酰胺（TAA）引起的肝损伤中，高血糖调节肝驻留巨噬细胞，库普弗细胞（KCs）的功能和机制仍然未知。在这项研究中，我们通过抑制TAA诱导的肝损伤模型中KCs的自噬诱导作用，来评估高血糖在调节NOD样受体家族含吡啶域3蛋白（NLRP3）炎性小体激活中的作用。链脲佐菌素治疗可诱发I型糖尿病/高血糖症。与对照组相比，高血糖小鼠肝内炎症和肝损伤明显增加。在高血糖小鼠的KC中检测到增强的NLRP3炎性体激活，与对照组小鼠相比，NLRP3的基因诱导和蛋白水平提高，caspase-1裂解，凋亡相关斑点样蛋白（包含caspase募集域和白介素1β）的增加所显示。NLRP3拮抗剂CY-09的抑制作用可有效抑制KCs中的炎性体活化并减轻高血糖小鼠的肝损伤。此外，通过透射电子显微镜检测发现抑制的自噬激活，从TAA应激的高血糖小鼠中分离出的KCs中LC3B蛋白表达降低和p-62蛋白降解。有趣的是，在来自TAA应激的高血糖小鼠的KC中发现抑制了5'AMP激活的蛋白激酶（AMPK）但增强了哺乳动物雷帕霉素（mTOR）激活的靶标。通过其激动剂5-氨基咪唑-4-羧酰胺核糖核苷酸（AICAR）激活AMPK或通过小干扰RNA敲低mTOR信号恢复了自噬激活，并随后抑制了KC中的NLRP3炎性体激活，从而最终减少了高血糖症中TAA诱导的肝损伤老鼠。我们的研究结果表明，高血糖症通过抑制AMPK / mTOR介导的自噬，促进肝驻留巨噬细胞NLRP3炎性小体活化，从而加剧了TAA诱导的急性肝损伤。该研究为预防高血糖下毒素诱导的急性肝损伤提供了新的靶标。我们的研究结果表明，高血糖症通过抑制AMPK / mTOR介导的自噬，促进肝驻留巨噬细胞NLRP3炎性小体活化，从而加剧了TAA诱导的急性肝损伤。该研究为预防高血糖下毒素诱导的急性肝损伤提供了新的靶标。我们的研究结果表明，高血糖症通过抑制AMPK / mTOR介导的自噬，促进肝驻留巨噬细胞NLRP3炎性小体活化，从而加剧了TAA诱导的急性肝损伤。该研究为预防高血糖下毒素诱导的急性肝损伤提供了新的靶标。