Department of Cardiology, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510630, China.
Department of Cardiology, The First People's Hospital of Xinjiang Kashi Area, Kashi, 844000, Xinjiang, China.
Arch Biochem Biophys. 2019 Sep 15;672:108052. doi: 10.1016/j.abb.2019.07.017. Epub 2019 Jul 24.
Vascular disease is one of the most significant threats to the lives of patients suffering from diabetes, and chronic exposure of vascular endothelial cells to high glucose has been shown to significantly contribute to the process of endothelial cell dysfunction, one of the earliest events in diabetes-associated vascular disease. Nucleotide oligomerization domain (NOD)-like receptor pyrin domain-containing 3 (NLRP3) inflammasome plays a key role in initiating the inflammatory process by facilitating the production of interleukin-1β (IL-1β) and IL-18. ASC and caspase 1 are also implicated in NLRP3 inflammasome-mediated chronic inflammation. While under normal conditions, a balance exists between oxidants and antioxidants, exposure to high glucose significantly increases the production of ROS, which is enhanced by NOX4 expression. In the present study, we explored the role of orexin A, an endogenous peptide produced in the hypothalamus, in high glucose-induced activation of the NLRP3 inflammasome, oxidative stress, and expression of several key cytokines. Our findings demonstrate that orexin A exerts potent antioxidant effects in human aortic endothelial cells exposed to high glucose by inhibiting mitochondrial ROS and expression of NOX4 at both the mRNA and protein levels as revealed by MitoSOX staining, real-time PCR, and Western blot analysis. We also show that orexin A inhibits high glucose-induced expression of TxNIP, which is crucial to the activation of the NLRP3 inflammasome, as well as that of HMGB1. We confirmed via real-time PCR and Western blot analysis that orexin A suppressed the production of the inflammatory cytokines IL-1β and IL-18. Additionally, through SIRT1 knockdown siRNA experimentation, we confirmed that SIRT1 knockdown abolishes the effects of orexin A described above, thereby indicating a critical role of SIRT in the capacity of orexin A to ameliorate high glucose-induced oxidative stress and activation of NLRP3 inflammasome.
血管疾病是糖尿病患者生命面临的最大威胁之一，研究表明，血管内皮细胞长期暴露于高浓度葡萄糖中，会显著促进内皮细胞功能障碍的发生，而内皮细胞功能障碍是糖尿病相关血管疾病的早期事件之一。核苷酸寡聚化结构域（NOD）样受体富含亮氨酸重复序列 3（NLRP3）炎性小体通过促进白细胞介素-1β（IL-1β）和白细胞介素-18（IL-18）的产生，在启动炎症过程中发挥关键作用。ASC 和半胱天冬酶 1 也参与 NLRP3 炎性小体介导的慢性炎症。虽然在正常情况下，氧化剂和抗氧化剂之间存在平衡，但暴露于高浓度葡萄糖会显著增加 ROS 的产生，而 NOX4 的表达会增强这种产生。在本研究中，我们探讨了内源性肽下丘脑分泌素 A 在高糖诱导的 NLRP3 炎性小体激活、氧化应激和几种关键细胞因子表达中的作用。我们的研究结果表明，下丘脑分泌素 A 通过抑制线粒体 ROS 和 NOX4 的表达，发挥其在人主动脉内皮细胞中的抗氧化作用，从而抑制高糖诱导的 NLRP3 炎性小体激活。通过 MitoSOX 染色、实时 PCR 和 Western blot 分析证实，下丘脑分泌素 A 可抑制高糖诱导的 TxNIP 表达，这对 NLRP3 炎性小体的激活至关重要，同时也抑制了 HMGB1 的表达。我们通过实时 PCR 和 Western blot 分析证实，下丘脑分泌素 A 抑制了炎症细胞因子 IL-1β 和 IL-18 的产生。此外，通过 SIRT1 敲低 siRNA 实验，我们证实 SIRT1 敲低可消除下丘脑分泌素 A 的上述作用，从而表明 SIRT1 在下丘脑分泌素 A 改善高糖诱导的氧化应激和 NLRP3 炎性小体激活的能力中发挥关键作用。
