Zhou Boda, Zu Lingyun, Chen Yong, Zheng Xilong, Wang Yuhui, Pan Bing, Dong Min, Zhou Enchen, Zhao Mingming, Zhang Youyi, Zheng Lemin, Gao Wei
Department of Cardiology, Key Laboratory of Molecular Cardiovascular Sciences of Ministry of Education, and Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Ministry of Health, Peking University Third Hospital, No. 49 North Garden Road, Haidian District, Beijing, 100191, China.
Department of Neurology, People's Hospital of Deyang City, Deyang, 618000, China.
Lipids Health Dis. 2017 Jan 10;16(1):3. doi: 10.1186/s12944-016-0388-z.
High density lipoprotein (HDL) has been proved to be a protective factor for coronary heart disease. Notably, HDL in atherosclerotic plaques can be nitrated (NO-oxHDL) and chlorinated (Cl-oxHDL) by myeloperoxidase (MPO), likely compromising its cardiovascular protective effects.
Here we determined the effects of NO-oxHDL and Cl-oxHDL on SMC migration using wound healing and transwell assays, proliferation using MTT and BrdU assays, and apoptosis using Annexin-V assay in vitro, as well as on atherosclerotic plaque stability in vivo using a coratid artery collar implantation mice model.
Our results showed that native HDL promoted SMC proliferation and migration, whereas NO-oxHDL and Cl-oxHDL inhibited SMC migration and reduced capacity of stimulating SMC proliferation as well as migration, respectively. OxHDL had no significant influence on SMC apoptosis. In addition, we found that ERK1/2-phosphorylation was significantly lower when SMCs were incubated with NO-oxHDL and Cl-oxHDL. Furthermore, transwell experiments showed that differences between native HDL, NO-oxHDL and Cl-oxHDL was abolished after PD98059 (MAPK kinase inhibitor) treatment. In aortic SMCs from scavenger receptor BI (SR-BI) deficient mice, differences between migration of native HDL, NO-oxHDL and Cl-oxHDL treated SMCs vanished, indicating SR-BI's possible role in HDL-associated SMC migration. Importantly, NO-oxHDL and Cl-oxHDL induced neointima formation and reduced SMC positive staining cells in atherosclerotic plaque, resulting in elevated vulnerable index of atherosclerotic plaque.
These findings implicate MPO-catalyzed oxidization of HDL may contribute to atherosclerotic plaque instability by inhibiting SMC proliferation and migration through MAPK-ERK pathway which was dependent on SR-BI.
高密度脂蛋白（HDL）已被证明是冠心病的保护因素。值得注意的是，动脉粥样硬化斑块中的HDL可被髓过氧化物酶（MPO）硝化（NO-oxHDL）和氯化（Cl-oxHDL），这可能会损害其心血管保护作用。
在此，我们使用伤口愈合和Transwell实验测定了NO-oxHDL和Cl-oxHDL对平滑肌细胞（SMC）迁移的影响，使用MTT和BrdU实验测定了其对SMC增殖的影响，使用Annexin-V实验在体外测定了其对SMC凋亡的影响，并使用颈动脉环植入小鼠模型在体内测定了其对动脉粥样硬化斑块稳定性的影响。
我们的结果表明，天然HDL促进SMC增殖和迁移，而NO-oxHDL和Cl-oxHDL分别抑制SMC迁移，并降低刺激SMC增殖以及迁移的能力。氧化型HDL（OxHDL）对SMC凋亡无显著影响。此外，我们发现当SMC与NO-oxHDL和Cl-oxHDL孵育时，细胞外信号调节激酶1/2（ERK1/2）的磷酸化水平显著降低。此外，Transwell实验表明，在使用PD98059（丝裂原活化蛋白激酶激酶抑制剂）处理后，天然HDL、NO-oxHDL和Cl-oxHDL之间的差异消失。在清道夫受体BI（SR-BI）缺陷小鼠的主动脉SMC中，天然HDL、NO-oxHDL和Cl-oxHDL处理的SMC迁移差异消失，表明SR-BI在HDL相关的SMC迁移中可能发挥作用。重要的是，NO-oxHDL和Cl-oxHDL诱导动脉粥样硬化斑块中新生内膜形成并减少SMC阳性染色细胞，导致动脉粥样硬化斑块的易损指数升高。
这些发现表明，MPO催化的HDL氧化可能通过依赖于SR-BI的丝裂原活化蛋白激酶-ERK途径抑制SMC增殖和迁移，从而导致动脉粥样硬化斑块不稳定。
