Arginine methylation by PRMT6 as a novel stemness and metabolic regulator in hepatocellular carcinoma

Objective:Arginine methylation is a common posttranslational modification that plays pivotal roles in signal transduction.However,its function in human diseases is poorly understood.Protein methyltransferase 6(PRMT6)belongs to the type I PRMT enzyme family,responsible for catalyzing the asymmetric dimethylation of arginine residues in proteins.

Arginine methylation of ALKBH5 by PRMT6 promotes breast tumorigenesis via LDHA-mediated glycolysis

ALKBH5 is a master regulator of N6-methyladenosine(m6A)modification,which plays a crucial role in many biological processes.Here,we show that ALKBH5 is required for breast tumor growth.Interestingly,PRMT6 directly methylates ALKBH5 at R283,which subsequently promotes breast tumor growth.Furthermore,arginine methylation of ALKBH5 by PRMT6 increases LDHA RNA stability via m6A demethylation,leading to increased aerobic glycolysis.Moreover,PRMT6-mediated ALKBH5 arginine methylation is confirmed in PRMT6-knockout mice.Collectively,these findings identify a PRMT6-ALKBH5-LDHA signaling axis as a novel target for the treatment of breast cancer.

PRMT6 promotes tumorigenicity and cisplatin response of lung cancer through triggering 6PGD/ENO1 mediated cell metabolism

Metabolic reprogramming is a hallmark of cancer,including lung cancer.However,the exact underlying mechanism and therapeutic potential are largely unknown.Here we report that protein arginine methyltransferase 6(PRMT6)is highly expressed in lung cancer and is required for cell metabolism,tumorigenicity,and cisplatin response of lung cancer.PRMT6 regulated the oxidative pentose phosphate pathway(PPP)flux and glycolysis pathway in human lung cancer by increasing the activity of 6-phosphogluconate dehydrogenase(6PGD)and a-enolase(ENO1).Furthermore,PRMT6 methylated R324 of 6PGD to enhancing its activity;while methylation at R9 and R372 of ENO1 promotes formation of active ENO1 dimers and 2-phosphoglycerate(2-PG)binding to ENO1,respectively.Lastly,targeting PRMT6 blocked the oxidative PPP flux,glycolysis pathway,and tumor growth,as well as enhanced the antitumor effects of cisplatin in lung cancer.Together,this study demonstrates that PRMT6 acts as a posttranslational modification(PTM)regulator of glucose metabolism,which leads to the pathogenesis of lung cancer.It was proven that the PRMT6-6PGD/ENO1 regulatory axis is an important determinant of carcinogenesis and may become a promising cancer therapeutic strategy.

蛋白质精氨酸甲基转移酶调控骨形成与骨愈合的研究进展

蛋白质精氨酸甲基化是由蛋白质精氨酸甲基转移酶(PRMTs)介导的调控蛋白质功能的重要翻译后修饰(PTM),其与众多疾病的发生发展密切相关。精氨酸的甲基化修饰与炎症相关疾病及骨折愈合关系密切,PRMTs表达下降可导致骨折延迟愈合甚至不愈合。PRMT5、PRMT6在骨折愈合方面均有重要意义,其与PI3K-AKT通路、NF-κB通路息息相关。探讨蛋白质精氨酸甲基化与骨折愈合之间的联系,可为预防骨折延迟愈合甚至不愈合提供新思路。

The methyltransferase PRMT6 attenuates antiviral innate immunity by blocking TBK1–IRF3 signaling

Protein arginine methyltransferases(PRMTs)play diverse biological roles and are specifically involved in immune cell development and inflammation.However,their role in antiviral innate immunity has not been elucidated.Viral infection triggers the TBK1–IRF3 signaling pathway to stimulate the production of type-I interferon,which mediates antiviral immunity.We performed a functional screen of the nine mammalian PRMTs for regulators of IFN-βexpression and found that PRMT6 inhibits the antiviral innate immune response.Viral infection also upregulated PRMT6 protein levels.We generated PRMT6-deficient mice and found that they exhibited enhanced antiviral innate immunity.PRMT6 deficiency promoted the TBK1–IRF3 interaction and subsequently enhanced IRF3 activation and type-I interferon production.Mechanistically,viral infection enhanced the binding of PRMT6 to IRF3 and inhibited the interaction between IRF3 and TBK1;this mechanism was independent of PRMT6 methyltransferase activity.Thus,PRMT6 inhibits antiviral innate immunity by sequestering IRF3,thereby blocking TBK1-IRF3 signaling.Our work demonstrates a methyltransferase-independent role for PRMTs.It also identifies a negative regulator of the antiviral immune response,which may protect the host from the damaging effects of an overactive immune system and/or be exploited by viruses to escape immune detection.

组蛋白精氨酸甲基化酶在人体外受精发育阻滞胚胎中的功能研究

目的探究组蛋白精氨酸甲基化酶(PRMT)在体外受精的人类胚胎发育阻滞中的作用。方法收集丢弃的70枚体外受精人类胚胎,选取12枚正常发育的胚胎为正常组,12枚发育阻滞胚胎为阻滞组。蛋白印迹和免疫荧光检测2组组蛋白精氨酸甲基化酶6(PRMT6)蛋白质水平,蛋白印迹检测组蛋白H3在精氨酸2的二甲基化(H3R2me2)和组蛋白H3在赖氨酸4的三甲基化(H3K4me3)水平。敲除46枚发育阻滞胚胎中的PRMT6(PRMT6敲除组,n=46),qPCR和蛋白印迹检测阻滞组和PRMT6敲除组的PRMT6 RNA、PRMT6蛋白、H3R2me2和H3K4me3水平,多能性标记Oct4、Nanog和Sox2,观察阻滞组和PRMT6q敲除组胚胎培养7 d的情况。结果与正常组相比,阻滞组的PRMT6蛋白质水平显著增加[(1.160±0.054)比(1.530±0.13)],H3R2me2升高[(1.340±0.019)比(1.710±0.011)],H3K4me3水平下降[(1.650±0.030)比(1.220±0.015)],差异有统计学意义(P<0.05)。与阻滞组比较,PRMT6敲除组PRMT6 RNA[(1.660±0.029)比(1.230±0.017)]、PRMT6蛋白[(1.400±0.030)比(1.050±0.058)]及H3R2me2蛋白水平显著下调[(1.410±0.011)比(1.340±0.019)],而H3K4me3水平升高[(1.710±0.011)比(1.340±0.019)];多能性标记Oct4[(1.710±0.016)比(1.160±0.049)]、Nanog[(1.690±0.089)比(1.260±0.051)]和Sox2[(1.680±0.091)比(1.310±0.057)]的水平被下调,差异有统计学意义(P<0.05)。结论敲除PRMT6可以挽救部分发育阻滞的胚胎,甚至单个发育受阻的胚胎也可以发育成融合胚胎。敲除PRMT6可促进人体外受精发育阻滞胚胎的发育。