Role of melatonin in regulating circadian rhythm-mediated autophagy in podocytes in diabetic nephropathy
10.3760/cma.j.cn441217-20230320-00328
- VernacularTitle:褪黑素调控足细胞昼夜节律介导的自噬在糖尿病肾病中的作用
- Author:
Lulu WANG
1
;
Han TIAN
;
Junwei YANG
;
Lei JIANG
Author Information
1. 南京医科大学第二附属医院肾脏病中心，南京 210000
- Keywords:
Podocytes;
Diabetic nephropathies;
Biological clocks;
Autophagy;
Melatonin;
High glucose
- From:
Chinese Journal of Nephrology
2023;39(10):768-777
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the changes of podocyte circadian rhythm in the high-glucose environment and diabetic nephropathy (DN) mouse model and the protective effect of melatonin on podocyte injury in DN.Methods:Primary podocytes were cultured in vitro and divided into 3 groups: control group, high glucose (30 mmol/L) group and high glucose (30 mmol/L) treated with melatonin (0.1 mmol/L or 0.5 mmol/L) group. The podocytes were collected every 4 hours for 24 hours, synchronized with dexamethasone (100 nmol/L) for 2 hours, which was recorded as zeitgeber time 0 point. Male C57BL/6J mice aged 6-8 weeks and weighing about 20 g were randomly (randomized block) assigned to three groups: control group, DN (high-fat diet+streptozotocin 120 mg/kg intravenously injected) group, and DN (high-fat diet+streptozotocin 120 mg/kg intravenously) treated with melatonin (20 mg/kg intragastric treatment) group (melatonin group). Real-time quantitative PCR was used to detect the mRNA levels of rhythm genes in podocytes. Western blotting was used to detect the protein expression levels of circadian clock genes (Clock and Bmal1), podocyte marker proteins (Nephrin, Synaptopodin, WT1, and Desmin) and autophagy-related proteins (Beclin1, LC3Ⅱ/Ⅰ and P62). Immunofluorescence staining was used to detect the protein expression level of WT1, and immunohistochemistry was used to analyze the protein expression levels of P62 and cleaved-caspase-3 in renal tissues of mice. The pathological changes of renal glomerulus were observed under electron microscope. Results:(1) Dexamethasone reseted the expression and rhythmic oscillation of circadian clock genes in podocytes. The circadian rhythmic oscillations of Clock and Ck1e mRNA in the high glucose group were flattened compared to the control group, and the circadian rhythmic oscillations in Clock and Ck1e mRNA expression were partial recovery in high glucose treated with melatonin group (all P<0.05). (2) Compared with the control group, the protein expression levels of Nephrin, Synaptopodin and WT1 were lower while Desmin was higher in the high glucose group (all P<0.05). The protein expression levels of Nephrin, Synaptopodin and WT1 were higher and the protein expression level of Desmin was lower in the high glucose treated with melatonin (0.5 mmol/L) group compared with the high glucose group (all P<0.05). (3) The invivo experimental results showed that compared with the DN group, melatonin group had higher protein expression levels of glomerular Nephrin and WT1, and lower urinary albumin/creatinine ratio, width of foot process and thickness of glomerular basement membrane (all P<0.05). The protein expression levels of Beclin1 and LC3Ⅱ/Ⅰ in the DN group were lower than those in the control group, and the protein expression level of P62 was higher than that in the control group (all P<0.05). Compared with the DN group, the protein expression levels of Beclin1 and LC3Ⅱ/Ⅰ in the melatonin group were significantly higher, and the protein expression level of P62 was lower (all P<0.05). Conclusions:Melatonin can partially restore the circadian rhythm of clock genes in high-glucose environment, improve autophagy and alleviate injury in podocytes.
