Inactivation of SERCA2 Cys⁶⁷⁴ accelerates aortic aneurysms by suppressing PPARγ

Abstract

Background and Purpose Inactivation of Cys674 (C674) in the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2) causes intracellular Ca2+ 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. Experimental Approach 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. Key Results 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. Conclusions and Implications 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.

Construction and analysis of competing endogenous RNA network and patterns of immune infiltration in abdominal aortic aneurysm

“…Studies in the Ang II-induced AAA mouse model reveal that PPARG upregulates the expression of anti-inflammatory cytokines such as IL-10, thereby slowing the process of AAA development and rupture ( 31 ). The activators of PPARG , such as rosiglitazone and pioglitazone, have been shown to alleviate the development and rupture of Ang II-induced aneurysms in mouse models ( 32 – 34 ). Besides, this study also found that PPARG may exert its impacts through hsa_circ_0002722-miR-130a/b-3p.…”

Substitution of SERCA2 Cys674 accelerates aortic aneurysm by inducing endoplasmic reticulum stress and promoting cell apoptosis

“…The mice were monitored every day in the first week after operation. We have learned from our previous studies that some mice did not develop aortic aneurysms, whereas some mice died prematurely of aneurysm rupture, but found that most aneurysm-related indexes measured in 10 or 11 mice of each group were significantly different between WT and SKI mice (Que et al, 2020(Que et al, , 2021. Therefore, we adopted this sample size for the current study. )…”

“…Aortic SMCs were isolated from 8-week-old male WT and SKI mice and cultured in DMEM supplemented with 10% FBS (ExCell Bio, Cat# FSP500), 100 UÁml À1 penicillin, and 100 μgÁml À1 streptomycin at 37 C in a humidified atmosphere containing 5% CO 2 (Que et al, 2021). SMC phenotype was confirmed by α-SMA immunostaining.…”

“…the progression of aortic aneurysm (Fan et al, 2010;Golledge et al, 2007;Meng et al, 2014;Wang et al, 2012). We have reported that the substitution of C674 by activation of the NFAT/NF-κB (p-p65NF-κB) pathway and down-regulation of PPARγ to up-regulate these aneurysm related proteins, leads to enhance cell proliferation, migration, and macrophage adhesion to aortic SMCs, all of which could be ameliorated by the NFAT/NF-κB pathway inhibitor cyclosporin A or the PPARγ activator pioglitazone (Que et al, 2020(Que et al, , 2021.…”

“…We have found that the irreversible oxidation of C674 occurs frequently in mouse or human aortic aneurysms (Que et al, 2020). Replacing C674 with Ser 674 (Serine-674, S674) to simulate the irreversible oxidation of C674 thiol promotes the phenotypic transition of aortic SMCs and exacerbates angiotensin IIinduced aortic aneurysm, and the disruption of the balance between PPARγ and nuclear factor of activated T-lymphocytes (NFAT)/NF-κB in these cells is involved during the development of aortic aneurysm (Que et al, 2020(Que et al, , 2021. However, it remains elusive how the irreversible oxidation of C674 of SERCA2 in aortic SMCs initiates and promotes aortic aneurysm.…”