Lu Xiangxue, Li Han, Wang Shixiang
Department of Blood Purification, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China.
Front Mol Biosci. 2021 Feb 9;7:615816. doi: 10.3389/fmolb.2020.615816. eCollection 2020.
Cardiovascular disease is the most common complication and leading cause of death in maintenance hemodialysis patients. Previous studies have found that disorders of cystathionine-gamma-lyase/hydrogen sulfide (CSE/HS) system in maintenance hemodialysis patients are correlated with the risk of cardiovascular disease. Although the role of CSE/HS system in UAAS has been preliminarily explored, the molecular mechanism of CSE/HS is still not systematically elaborated, and the molecular mechanism of nPKCδ and its related signaling pathway in UAAS is still not thoroughly studied. Forty chronic kidney disease (CHD) patients were studied and the activation of nPKCδ in peripheral blood mononuclear cells (PBMCs) were detected. ApoE mice aged 6 weeks were treated with 5/6 nephrectomy and high-fat diet to make UAAS model. They were divided into Sham group (Sham group), UAAS group (UAAS group), UAAS+L-cysteine group (UAAS+L-cys group), UAAS+sodium hydrosulfide group (UAAS+NaHS group) and UAAS+propargylglycine group (UAAS+PPG group). The UAAS+L-cys group, UAAS+NaHS group and UAAS+PPG group were respectively given L-cys, NaHS and PPG by intraperitoneal injection. The aorta was taken 6 weeks after surgery. Western blot was used to detect the activation of nPKCδ, the phosphorylation of Akt, and the expression of VCAM-1 in the aorta of mice. The membrane translocation of nPKCδ in CHD patients with plaque was higher than that in CHD patients without plaque. The membrane translocation of nPKCδ and the expression of VCAM-1 in UAAS group was higher than sham group, L-cys or NaHS injection could suppress the membrane translocation of nPKCδ and the expression of VCAM-1, but PPG treatment resulted in more membrane translocation of nPKCδ and the expression of VCAM-1 (<0.05, n=6 per group). Akt phosphorylation in UAAS group was lower than sham group, and L-cys or NaHS injection could suppress the degradation of Akt phosphorylation, but PPG treatment resulted in more decrease in the Akt phosphorylation (<0.05, n=6 per group). Endogenous CSE/HS system protected against the formation of UAAS via nPKCδ/Akt signal pathway. The imbalance of CSE/HS system may participate in the formation of UAAS by affecting the expression of downstream molecule VCAM-1, which may be mediated by nPKCδ/Akt signaling pathway.
心血管疾病是维持性血液透析患者最常见的并发症和主要死因。以往研究发现，维持性血液透析患者中胱硫醚-γ-裂解酶/硫化氢（CSE/HS）系统紊乱与心血管疾病风险相关。虽然已初步探讨了CSE/HS系统在动脉粥样硬化中的作用，但CSE/HS的分子机制仍未得到系统阐述，nPKCδ及其相关信号通路在动脉粥样硬化中的分子机制也尚未得到深入研究。本研究纳入40例慢性肾脏病（CKD）患者，检测外周血单个核细胞（PBMCs）中nPKCδ的激活情况。将6周龄载脂蛋白E（ApoE）小鼠行5/6肾切除并给予高脂饮食，制备动脉粥样硬化模型。将其分为假手术组（Sham组）、动脉粥样硬化组（UAAS组）、UAAS+L-半胱氨酸组（UAAS+L-cys组）、UAAS+氢硫化钠组（UAAS+NaHS组）和UAAS+炔丙基甘氨酸组（UAAS+PPG组）。UAAS+L-cys组、UAAS+NaHS组和UAAS+PPG组分别腹腔注射L-半胱氨酸、氢硫化钠和炔丙基甘氨酸。术后6周取主动脉。采用蛋白质免疫印迹法检测小鼠主动脉中nPKCδ的激活、Akt的磷酸化及血管细胞黏附分子-1（VCAM-1）的表达。有斑块的CKD患者PBMCs中nPKCδ的膜转位高于无斑块的CKD患者。UAAS组nPKCδ的膜转位及VCAM-1的表达高于假手术组，注射L-半胱氨酸或氢硫化钠可抑制nPKCδ的膜转位及VCAM-1的表达，但炔丙基甘氨酸处理导致nPKCδ的膜转位及VCAM-1的表达增加（P<0.05，每组n=6）。UAAS组Akt磷酸化低于假手术组，注射L-半胱氨酸或氢硫化钠可抑制Akt磷酸化的降低，但炔丙基甘氨酸处理导致Akt磷酸化进一步降低（P<0.05，每组n=6）。内源性CSE/HS系统通过nPKCδ/Akt信号通路预防动脉粥样硬化的形成。CSE/HS系统失衡可能通过影响下游分子VCAM-1的表达参与动脉粥样硬化的形成，这可能由nPKCδ/Akt信号通路介导。
