目的 探讨精氨酸脱亚胺酶4(PAD4)介导的瓜氨酸化组蛋白H3(H3cit)在脓毒症相关急性肾损伤(AKI)中的作用机制.方法 将30 只C57BL/6J小鼠随机分为对照组、模型组和给药组,每组10 只.给药组连续7d灌胃PAD4 抑制剂BB-Cl-amidine,其余两组予同体积生理盐水.7 d后对模型组和给药组小鼠腹腔注射脂多糖(LPS)构建AKI模型.24 h后处死小鼠,检测各组小鼠血清肌酐(SCr)、尿素氮(BUN)、H3cit水平,尿液中尿微量白蛋白(UALb)/肌酐(Cr)比值水平,以及肾组织丙二醛(MDA)和超氧化物歧化酶(SOD)水平,并分析SCr、BUN、UALb/Cr比值水平与H3cit水平的相关性.应用HE染色法检测各组小鼠肾脏损伤病理情况.采用Western blot法检测肾脏PAD4 和H3cit蛋白表达水平.采用HEK293T细胞进行实验,设置空白组、LPS组、LPS+BB-Cl-amidine组,通过Western blot法检测各组PAD4 和H3cit蛋白表达水平,通过CCK-8 法检测各组细胞增殖水平.结果 在动物实验中,与对照组比较,模型组小鼠血清SCr、BUN和H3cit水平升高,尿UALb/Cr比值升高,肾组织MDA水平升高、SOD水平降低,肾脏病理损伤加重,PAD4 和H3cit蛋白表达升高,差异有统计学意义(P＜0.05).与模型组比较,给药组小鼠血清中SCr、BUN和H3cit水平降低,尿UALb/Cr比值降低,肾组织MDA水平降低、SOD水平升高,肾脏病理损伤缓解,H3cit蛋白表达降低,差异有统计学意义(P＜0.05).H3cit水平与SCr、BUN、UALb/Cr比值水平呈正相关(P＜0.05).在细胞实验中,与空白组比较,LPS组细胞PAD4 和H3cit蛋白表达升高,细胞增殖水平降低,差异有统计学意义(P＜0.05).与LPS组比较,LPS+BB-Cl-amidine组细胞H3cit蛋白表达降低,细胞增殖水平升高,差异有统计学意义(P＜0.05).结论 PAD4 介导的H3cit可促进脓毒症相关AKI的发展,抑制PAD4 活性可以有效减少肾脏细胞损伤.

Objective:Acute myeloid leukemia(AML)is a highly heterogeneous and recurrent hematological malignancy.Despite the emergence of novel chemotherapy drugs,AML patients'complete remission(CR)remains unsatisfactory.Consequently,it is imperative to discover new therapeutic targets or medications to treat AML.Such epigenetic changes like DNA methylation and histone modification play vital roles in AML.Peptidylarginine deminase(PAD)is a protein family of histone demethylases,among which the PAD2 and PAD4 expression have been demonstrated to be elevated in AML patients,thus suggesting a potential role of PADs in the development or maintenance of AML and the potential for the identification of novel therapeutic targets.Methods:AML cells were treated in vitro with the pan-PAD inhibitor BB-Cl-Amidine(BB-Cl-A).The AML cell lines were effectively induced into apoptosis by BB-Cl-A.However,the PAD4-specific inhibitor GSK484 did not.Results:PAD2 played a significant role in AML.Furthermore,we found that BB-Cl-A could activate the endoplasmic reticulum(ER)stress response,as evidenced by an increase in phosphorylated PERK(p-PERK)and eIF2a(p-eIF2a).As a result of the ER stress activation,the BB-Cl-A effectively induced apoptosis in the AML cells.Conclusion:Our findings indicated that PAD2 plays a role in ER homeostasis maintenance and apoptosis prevention.Therefore,targeting PAD2 with BB-Cl-A could represent a novel therapeutic strategy for treating AML.