Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, China.
Br J Pharmacol. 2021 Jun;178(11):2305-2323. doi: 10.1111/bph.15411. Epub 2021 Mar 19.
Inactivation of Cys (C674) in the sarcoplasmic/endoplasmic reticulum Ca ATPase 2 (SERCA2) causes intracellular Ca accumulation, which activates calcineurin-mediated nuclear factor of activated T-lymphocytes (NFAT)/NF-κB pathways, and results in the phenotypic modulation of smooth muscle cells (SMCs) to accelerate angiotensin II-induced aortic aneurysms. Our goal was to investigate the mechanism involved.
We used heterozygous SERCA2 C674S knock-in (SKI) mice, where half of C674 was substituted by serine, to mimic partial irreversible oxidation of C674. The aortas of SKI mice and their littermate wild-type mice were collected for RNA sequencing, cell culture, protein expression, luciferase activity and aortic aneurysm analysis.
Inactivation of C674 inhibited the promoter activity and protein expression of PPARγ, which could be reversed by inhibitors of calcineurin or NF-κB. In SKI SMCs, inhibition of NF-κB by pyrrolidinedithiocarbamic acid (PDTC) or overexpression of PPARγ2 reversed the protein expression of SMC phenotypic modulation markers and inhibited cell proliferation, migration, and macrophage adhesion to SMCs. Pioglitazone, a PPARγ agonist, blocked the activation of NFAT/NF-κB, reversed the protein expression of SMC phenotypic modulation markers, and inhibited cell proliferation, migration, and macrophage adhesion to SMCs in SKI SMCs. Furthermore, pioglitazone also ameliorated angiotensin II-induced aortic aneurysms in SKI mice.
The inactivation of SERCA2 C674 promotes the development of aortic aneurysms by disrupting the balance between PPARγ and NFAT/NF-κB. Our study highlights the importance of C674 redox status in regulating PPARγ to maintain aortic homeostasis.
肌浆网/内质网 Ca2+-ATP 酶 2（SERCA2）中半胱氨酸（C674）的失活导致细胞内 Ca2+积累，激活钙调神经磷酸酶介导的核因子活化 T 淋巴细胞（NFAT）/NF-κB 途径，导致平滑肌细胞（SMCs）表型调节加速血管紧张素 II 诱导的主动脉瘤。我们的目标是研究涉及的机制。
我们使用杂合子 SERCA2 C674S 敲入（SKI）小鼠，其中一半的 C674 被丝氨酸取代，以模拟 C674 的部分不可逆氧化。收集 SKI 小鼠及其同窝野生型小鼠的主动脉进行 RNA 测序、细胞培养、蛋白表达、荧光素酶活性和主动脉瘤分析。
C674 的失活抑制了 PPARγ的启动子活性和蛋白表达，这可以被钙调神经磷酸酶或 NF-κB 的抑制剂逆转。在 SKI SMC 中，吡咯烷二硫代氨基甲酸盐（PDTC）抑制 NF-κB 或过表达 PPARγ2 可逆转 SMC 表型调节标志物的蛋白表达，并抑制细胞增殖、迁移和巨噬细胞与 SMC 的黏附。PPARγ 激动剂吡格列酮阻断 NFAT/NF-κB 的激活，逆转 SMC 表型调节标志物的蛋白表达，并抑制 SKI SMC 中的细胞增殖、迁移和巨噬细胞与 SMC 的黏附。此外，吡格列酮还可改善 SKI 小鼠的血管紧张素 II 诱导的主动脉瘤。
SERCA2 C674 的失活通过破坏 PPARγ 和 NFAT/NF-κB 之间的平衡促进主动脉瘤的发展。我们的研究强调了 C674 氧化还原状态在调节 PPARγ 以维持主动脉稳态中的重要性。
