胱硫醚-γ-裂解酶/硫化氢体系调控PKCs特异性亚型在尿毒症加速性动脉粥样硬化中的作用及其机制研究

Uremic accelerated atherosclerosis (UAAS) is the leading cause of death in chronic kidney disease (CKD) patients, especially in chronic hemodialysis (CHD) patients. However, the molecular mechanisms of UAAS are still unclear. Hydrogen sulfide (H2S) is a kind of endogenous gaseous mediator. We found that lower plasma H2S concentration in CHD patients was a predictor of UAAS progression and cardiovascular mortality, and the expression of cystathionine-γ-lyase (CSE) in peripheral blood mononuclear cells was decreased. Furthermore, we detected the activation of protein kinase C family (PKCs), and found PKCbeta II and PKCdelta membrane translocation increased, but PKCepsilon membrane translocation decreased in 10 PKC isoforms, and also the Akt phosphorylation reduced. These findings suggest that CSE/H2S pathway may exert anti-UAAS effects by regulating the specific PKCs isoform and its related signaling pathways. Accordingly, this project will use dialysis patients plasma and peripheral mononuclear cells, mice UAAS model as well as primary cultured mice aortic endothelial cells and smooth muscle cells to clarify the signaling transduction mechanisms of CSE/H2S pathway protecting against UAAS through regulating the specific PKCs isoform and its interacting proteins by using biochemistry and molecular biology technology. The results will enrich our understanding of the mechanisms underlying UAAS, and provide new ideas and experimental basis for the prevention and treatment of cardiovascular disease in clinic.

尿毒症加速性动脉粥样硬化(UAAS)是透析患者首位死亡原因，但其发病机制尚未明确。硫化氢(H2S)是一种信号分子，我们已发现血浆H2S水平降低是透析患者UAAS及心血管死亡的预测因子；透析患者外周血单个核细胞胱硫醚-γ-裂解酶(CSE)表达下调；蛋白激酶C家族(PKCs)10个亚型中，PKCbetaⅡ和delta膜转位激活水平升高、PKCepsilon膜转位激活水平降低；同时Akt磷酸化水平降低。推测CSE/H2S体系可能通过调控PKCs特异性亚型及其相关信号通路发挥抗UAAS作用。据此，本研究拟利用透析患者血浆和单个核细胞、小鼠UAAS模型和原代培养的小鼠主动脉内皮细胞和平滑肌细胞，借助生物化学和分子生物学等技术，明确CSE/H2S体系调控PKCs特异性亚型和其相互作用蛋白在UAAS中的作用及信号转导机制。所获成果将丰富人们对UAAS发生机制的认识，为防治心血管疾病提供新思路和实验依据。

心血管疾病是慢性肾脏病(chronic kidney disease, CKD)，尤其是终末期肾脏病患者最常见的并发症和引起死亡的首位原因。维持性透析患者动脉粥样硬化性心血管疾病的发生率明显高于同龄普通人群，而且进展快、发病年龄提前，称为尿毒症加速性动脉粥样硬化(uremic accelerated atherosclerosis, UAAS)。多种传统与非传统危险因素均参与了UAAS发生与发展，然而其分子机制尚不清楚。本研究利用透析患者血浆和单个核细胞、小鼠UAAS模型和原代培养的小鼠主动脉内皮细胞和平滑肌细胞，借助生物化学和分子生物学等技术，研究发现： 1. 蛋白激酶C家族(protein kinase C, PKCs)特异性亚型激活参与UAAS的形成和发展；2. UAAS形成过程中，PKCs特异性亚型可与多种蛋白相互作用，促进或抑制UAAS的形成与发展；3. 在UAAS形成过程中，胱硫醚-γ-裂解酶(cystathionine-γ-lyase, CSE)/硫化氢(hydrogen sulfide, H2S)体系可通过调控PKCs特异性亚型而发挥抗UAAS作用。总之，本研究通过多个实验证实CSE/H2S体系调控PKCs特异性亚型及其相互作用蛋白在UAAS形成和发展中的作用。有关成果进一步丰富了人们对终末期肾脏病CHD患者UAAS形成机制的认识，并为临床预防治疗UAAS相关疾病提供了新的思路和实验依据。