Wang Ling-Fang, Cao Qing, Wen Ke, Xiao Yun-Fei, Chen Ting-Tao, Guan Xiao-Hui, Liu Yu, Zuo Li, Qian Yi-Song, Deng Ke-Yu, Xin Hong-Bo
National Engineering Research Center for Bioengineering Drugs and the Technologies, Institute of Translational Medicine, Nanchang University, Nanchang, China.
Front Physiol. 2019 Sep 3;10:1125. doi: 10.3389/fphys.2019.01125. eCollection 2019.
Our previous research showed that CD38 played vital roles in Ang-II induced hypertrophy and high fat diet induced heart injury. However, the role of CD38 in heart aging is still unknown. In the present study, we reported that CD38 knockdown significantly protected cardiomyocytes from D-galactose (D-gal)-induced cellular senescence. Cellular senescence was evaluated by -galactosidase staining, the expressions of genes closely related to aging including p16 and p21, and the ROS production, MDA content and the expressions of oxidant stress related genes were examined by biochemical analysis, Western blot and QPCR. Our results showed that the expression of CD38 was increased in H9c2 cells after D-gal treatment and the expressions of NAMPT and Sirt1 were downregulated in heart tissue from old mice. CD38 knockdown significantly reduced the number of SA--gal-positive cells and the expressions of p16 and p21 in H9c2 cells with or without D-gal treatment. The acetylation level of total protein was decreased in CD38 knockdown group, but the expression of Sirt3 was increased in CD38 knockdown group treated with D-gal. In addition, knockdown of CD38 significantly attenuated D-gal induced ROS production, MDA content and NOX4 expression in the cells. Inhibition Sirt1 partially reversed the effects of CD38 knockdown on D-gal induced senescence and oxidative stress. Furthermore, NAD supplementation reduced D-gal induced cellular senescence, ROS production and MDA content. The expression of SOD2 was increased and the NOX4 expression was decreased in H9c2 cells after NAD supplementation. Taken together, our results demonstrated that CD38 knockdown alleviated D-gal induced cell senescence and oxidative stress via NAD/Sirt1 signaling pathway.
我们之前的研究表明，CD38在血管紧张素II诱导的心肌肥大和高脂饮食诱导的心脏损伤中发挥着重要作用。然而，CD38在心脏衰老中的作用仍不清楚。在本研究中，我们报道CD38基因敲低可显著保护心肌细胞免受D-半乳糖（D-gal）诱导的细胞衰老。通过β-半乳糖苷酶染色评估细胞衰老，检测与衰老密切相关的基因如p16和p21的表达，并通过生化分析、蛋白质印迹法和定量聚合酶链反应检测活性氧（ROS）生成、丙二醛（MDA）含量以及氧化应激相关基因的表达。我们的结果显示，D-半乳糖处理后H9c2细胞中CD38的表达增加，老年小鼠心脏组织中烟酰胺磷酸核糖转移酶（NAMPT）和沉默信息调节因子1（Sirt1）的表达下调。无论有无D-半乳糖处理，CD38基因敲低均显著减少H9c2细胞中SA-β-半乳糖苷阳性细胞的数量以及p16和p21的表达。CD38基因敲低组总蛋白的乙酰化水平降低，但在D-半乳糖处理的CD38基因敲低组中Sirt3的表达增加。此外，CD38基因敲低显著减弱了D-半乳糖诱导的细胞内ROS生成、MDA含量和NADPH氧化酶4（NOX4）表达。抑制Sirt1部分逆转了CD38基因敲低对D-半乳糖诱导的衰老和氧化应激的影响。此外，补充烟酰胺腺嘌呤二核苷酸（NAD）可减少D-半乳糖诱导的细胞衰老、ROS生成和MDA含量。补充NAD后H9c2细胞中超氧化物歧化酶2（SOD2）的表达增加，NOX4表达降低。综上所述，我们的结果表明，CD38基因敲低通过NAD/Sirt1信号通路减轻了D-半乳糖诱导的细胞衰老和氧化应激。
