Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
Genomics Core Facility, Department of Transdisciplinary Research and Collaboration, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.
J Korean Med Sci. 2020 Sep 14;35(36):e305. doi: 10.3346/jkms.2020.35.e305.
Oxidative stress induced by chronic hyperglycemia is recognized as a significant mechanistic contributor to the development of diabetic kidney disease (DKD). Nonphagocytic nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) is a major source of reactive oxygen species (ROS) in many cell types and in the kidney tissue of diabetic animals. We designed this study to explore the therapeutic potential of chloroquine (CQ) and amodiaquine (AQ) for inhibiting mitochondrial Nox4 and diabetic tubular injury.
Human renal proximal tubular epithelial cells (hRPTCs) were cultured in high-glucose media (30 mM D-glucose), and diabetes was induced with streptozotocin (STZ, 50 mg/kg i.p. for 5 days) in male C57BL/6J mice. CQ and AQ were administered to the mice via intraperitoneal injection for 14 weeks.
CQ and AQ inhibited mitochondrial Nox4 and increased mitochondrial mass in hRPTCs under high-glucose conditions. Reduced mitochondrial ROS production after treatment with the drugs resulted in decreased endoplasmic reticulum (ER) stress, suppressed inflammatory protein expression and reduced cell apoptosis in hRPTCs under high-glucose conditions. Notably, CQ and AQ treatment diminished Nox4 activation and ER stress in the kidneys of STZ-induced diabetic mice. In addition, we observed attenuated inflammatory protein expression and albuminuria in STZ-induced diabetic mice after CQ and AQ treatment.
We substantiated the protective actions of CQ and AQ in diabetic tubulopathy associated with reduced mitochondrial Nox4 activation and ER stress alleviation. Further studies exploring the roles of mitochondrial Nox4 in the pathogenesis of DKD could suggest new therapeutic targets for patients with DKD.
慢性高血糖引起的氧化应激被认为是糖尿病肾病（DKD）发展的重要机制因素。非吞噬性烟酰胺腺嘌呤二核苷酸磷酸氧化酶 4（Nox4）是许多细胞类型和糖尿病动物肾脏组织中活性氧（ROS）的主要来源。我们设计了这项研究，以探索氯喹（CQ）和阿莫地喹（AQ）抑制线粒体 Nox4 和糖尿病肾小管损伤的治疗潜力。
将人肾近端小管上皮细胞（hRPTCs）在高糖培养基（30 mM D-葡萄糖）中培养，并通过腹腔注射链脲佐菌素（STZ，50 mg/kg 5 天）在雄性 C57BL/6J 小鼠中诱导糖尿病。通过腹腔注射向小鼠给予 CQ 和 AQ 治疗 14 周。
CQ 和 AQ 在高糖条件下抑制 hRPTCs 中的线粒体 Nox4 并增加线粒体质量。药物处理后线粒体 ROS 产生减少导致内质网（ER）应激减少，抑制高糖条件下 hRPTCs 中炎症蛋白表达和细胞凋亡。值得注意的是，CQ 和 AQ 治疗减轻了 STZ 诱导的糖尿病小鼠肾脏中 Nox4 的激活和 ER 应激。此外，我们观察到 CQ 和 AQ 治疗后 STZ 诱导的糖尿病小鼠中炎症蛋白表达和白蛋白尿减少。
我们证实了 CQ 和 AQ 在与减少线粒体 Nox4 激活和减轻 ER 应激相关的糖尿病小管病变中的保护作用。进一步研究探索线粒体 Nox4 在 DKD 发病机制中的作用可能为 DKD 患者提供新的治疗靶点。
