Endothelial cell-derived tetrahydrobiopterin prevents aortic valve calcification
Endothelial cell-derived tetrahydrobiopterin prevents aortic valve calcification
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DOI：
10.1093/eurheartj/ehac037
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发表时间：
2022-02-09
影响因子：
39.3
通讯作者：
Li, Fei
中科院分区：
文献类型：
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作者：
Liu, Zongtao;Dong, Nianguo;Li, Fei
目的四氢生物蝶呤(BH4)是内皮型一氧化氮合酶生物学功能的关键决定因素。本研究旨在探讨瓣膜内皮细胞(VEC)来源的BH4在主动脉瓣钙化中的作用。方法与结果钙化主动脉瓣膜病患者血浆和主动脉瓣BH4浓度及BH4/BH2比值明显低于对照组。钙化主动脉瓣中BH4生物合成的两个关键酶鸟苷5‘-三磷酸环水解酶I(GCH1)和二氢叶酸还原酶(DHFR)较正常主动脉瓣明显降低。与APOE(-/-)Gch1(fl/fl)小鼠相比，APOE(-/-)(APOE(-/-))(APOE(-/-)Gch1(fl/fl)Tie2(CRE))小鼠的血管内皮细胞特异性Gch1缺陷在24周的西方饮食(WD)挑战后，跨瓣峰值喷射速度、钙沉积、主动脉瓣小叶中矮小相关转录因子2(Runx2)、二氢乙锭(DHE)和3-硝基酪氨酸(3-NT)水平显著增加。氧化型低密度脂蛋白(ox-LDL)可诱导心脏瓣膜间质细胞(VICs)向成骨细胞分化，而BH4可阻断氧化低密度脂蛋白(OX-LDL)对血管内皮细胞的诱导分化。在ox-LDL刺激下，血管内皮细胞缺乏BH4可导致过氧亚硝酸盐生成增加，3-NT蛋白增加。过氧亚硝酸根生成物SIN-1在Y628通过动力蛋白相关蛋白1(Drp1)的酪氨酸硝化显著上调VICS中碱性磷酸酶(ALP)和Runx2的表达。最后，叶酸(FA)通过增加DHFR和挽救BH4生物合成而显著减轻WD喂养的APOE(-/-)小鼠的主动脉瓣钙化。结论内皮依赖性BH4水平的降低促进了过氧亚硝酸盐的形成，从而导致DRp1酪氨酸硝化和VIC的成骨分化，从而导致主动脉瓣钙化。饮食中补充FA通过挽救BH4的生物利用度来减轻高胆固醇血症引起的主动脉瓣钙化。
Aims Tetrahydrobiopterin (BH4) is a critical determinant of the biological function of endothelial nitric oxide synthase. The present study was to investigate the role of valvular endothelial cell (VEC)-derived BH4 in aortic valve calcification.Methods and results Plasma and aortic valve BH4 concentrations and the BH4:BH2 ratio were significantly lower in calcific aortic valve disease patients than in controls. There was a significant decrease of the two key enzymes of BH4 biosynthesis, guanosine 5'-triphosphate cyclohydrolase I (GCH1) and dihydrofolate reductase (DHFR), in calcified aortic valves compared with the normal ones. Endothelial cell-specific deficiency of Gch1 in Apoe(-/-) (Apoe(-/-)Gch1(fl/fl)Tie2(Cre)) mice showed a marked increase in transvalvular peak jet velocity, calcium deposition, runt-related transcription factor 2 (Runx2), dihydroethidium (DHE), and 3-nitrotyrosine (3-NT) levels in aortic valve leaflets compared with Apoe(-/-)Gch1(fl/fl) mice after a 24-week western diet (WD) challenge. Oxidized LDL (ox-LDL) induced osteoblastic differentiation of valvular interstitial cells (VICs) co-cultured with either si-GCH1- or si-DHFR-transfected VECs, while the effects could be abolished by BH4 supplementation. Deficiency of BH4 in VECs caused peroxynitrite formation increase and 3-NT protein increase under ox-LDL stimulation in VICs. SIN-1, the peroxynitrite generator, significantly up-regulated alkaline phosphatase (ALP) and Runx2 expression in VICs via tyrosine nitration of dynamin-related protein 1 (DRP1) at Y628. Finally, folic acid (FA) significantly attenuated aortic valve calcification in WD-fed Apoe(-/-) mice through increasing DHFR and salvaging BH4 biosynthesis.Conclusion The reduction in endothelial-dependent BH4 levels promoted peroxynitrite formation, which subsequently resulted in DRP1 tyrosine nitration and osteoblastic differentiation of VICs, thereby leading to aortic valve calcification. Supplementation of FA in diet attenuated hypercholesterolaemia-induced aortic valve calcification by salvaging BH4 bioavailability.