AdipoRon Protects against Tubular Injury in Diabetic Nephropathy by Inhibiting Endoplasmic Reticulum Stress

ShenQiWan ameliorates renal injury in type 2 diabetic mice by modulating mitochondrial fusion and endoplasmic reticulum stress

Background: ShenQiWan is commonly used in traditional Chinese medicine for the treatment of diabetic nephropathy, which is closely related to mitochondrial fusion and endoplasmic reticulum stress. This study aimed to investigate the intervention effect and molecular mechanisms of ShenQiWan on renal injury in KKAy mice. Methods: C57BL/6J mice (11 weeks old) were fed a regular diet upon arrival, while KKAy mice (11 weeks old) were fed a high-fat diet upon arrival. At 12 weeks of age, KKAy mice with random blood glucose ≥13.9 mmol/L were identified as diabetic mice and randomly divided into the model group (n = 30) and the treatment group (n = 30), while C57BL/6J mice of 12 weeks old (n = 30) served as the control group. The treatment group received daily aqueous decoction of ShenQiWan (13.5 g/kg), while the control group and model group received daily equal amounts of saline from 12 weeks old to 24 weeks old. The general status of mice was observed regularly, and fasting blood glucose and 24-hour urine microalbumin were measured. Ten mice were euthanized in each group at the age of 16, 20, and 24 weeks, serum samples were used for biochemical indexes and kidney tissues were used for morphological studies. GRP78, OPA1, MFN1, MFN2 mRNA and protein expression were detected by Real-time PCR, immunohistochemistry and Western blot. Results: The mice in the model group exhibited symptoms of lethargy, slow movement, obesity, polyuria and proteinuria. Morphological observation revealed pathological changes, including thickening of the glomerular basement membrane and interstitial fibrosis. After treatment with ShenQiWan, the fasting blood glucose level of KKAy mice was significantly reduced, urinary albuminuria was decreased, serum biochemical indexes were improved, renal tissue pathological changes were significantly alleviated. The results also showed a significant reduction in the expression of endoplasmic reticulum stress-related factor GRP78 and an increase in the expression of mitochondrial fusion-related factors OPA1, MFN1 and MFN2 after treatment with ShenQiWan. Conclusion: ShenQiWan can protect diabetic mice from renal damage by modulating mitochondrial fusion and alleviating endoplasmic reticulum stress, exerting its protective effects.

PACS-2 deficiency aggravates tubular injury in diabetic kidney disease by inhibiting ER-phagy

Autophagy of endoplasmic reticulum (ER-phagy) selectively removes damaged ER through autophagy-lysosome pathway, acting as an adaptive mechanism to alleviate ER stress and restore ER homeostasis. However, the role and precise mechanism of ER-phagy in tubular injury of diabetic kidney disease (DKD) remain obscure. In the present study, we demonstrated that ER-phagy of renal tubular cells was severely impaired in streptozocin (STZ)-induced diabetic mice, with a decreased expression of phosphofurin acidic cluster sorting protein 2 (PACS-2), a membrane trafficking protein which was involved in autophagy, and a reduction of family with sequence similarity 134 member B (FAM134B), one ER-phagy receptor. These changes were further aggravated in mice with proximal tubule specific knockout of Pacs-2 gene. In vitro, transfection of HK-2 cells with PACS-2 overexpression plasmid partially improved the impairment of ER-phagy and the reduction of FAM134B, both of which were induced in high glucose ambience; while the effect was blocked by FAM134B siRNA. Mechanistically, PACS-2 interacted with and promoted the nuclear translocation of transcription factor EB (TFEB), which was reported to activate the expression of FAM134B. Collectively, these data unveiled that PACS-2 deficiency aggravates renal tubular injury in DKD via inhibiting ER-phagy through TFEB/FAM134B pathway.

The role of Chinese herbal medicine in the treatment of diabetic nephropathy by regulating endoplasmic reticulum stress

Diabetic nephropathy (DN), a prevalent microvascular complication of diabetes mellitus, is the primary contributor to end-stage renal disease in developed countries. Existing clinical interventions for DN encompass lifestyle modifications, blood glucose regulation, blood pressure reduction, lipid management, and avoidance of nephrotoxic medications. Despite these measures, a significant number of patients progress to end-stage renal disease, underscoring the need for additional therapeutic strategies. The endoplasmic reticulum (ER) stress response, a cellular defense mechanism in eukaryotic cells, has been implicated in DN pathogenesis. Moderate ER stress can enhance cell survival, whereas severe or prolonged ER stress may trigger apoptosis. As such, the role of ER stress in DN presents a potential avenue for therapeutic modulation. Chinese herbal medicine, a staple in Chinese healthcare, has emerged as a promising intervention for DN. Existing research suggests that some herbal remedies may confer renoprotective benefits through the modulation of ER stress. This review explores the involvement of ER stress in the pathogenesis of DN and the advancements in Chinese herbal medicine for ER stress regulation, aiming to inspire new clinical strategies for the prevention and management of DN.

Cellular crosstalk of glomerular endothelial cells and podocytes in diabetic kidney disease

Diabetic kidney disease (DKD) is a serious microvascular complication of diabetes and is the leading cause of end-stage renal disease (ESRD). Persistent proteinuria is an important feature of DKD, which is caused by the destruction of the glomerular filtration barrier (GFB). Glomerular endothelial cells (GECs) and podocytes are important components of the GFB, and their damage can be observed in the early stages of DKD. Recently, studies have found that crosstalk between cells directly affects DKD progression, which has prospective research significance. However, the pathways involved are complex and largely unexplored. Here, we review the literature on cellular crosstalk of GECs and podocytes in the context of DKD, and highlight specific gaps in the field to propose future research directions. Elucidating the intricates of such complex processes will help to further understand the pathogenesis of DKD and develop better prevention and treatment options.

Endoplasmic Reticulum Stress in Diabetic Nephrology: Regulation, Pathological Role, and Therapeutic Potential

Recent progress has been made in understanding the roles and mechanisms of endoplasmic reticulum (ER) stress in the development and pathogenesis of diabetic nephropathy (DN). Hyperglycemia induces ER stress and apoptosis in renal cells. The induction of ER stress can be cytoprotective or cytotoxic. Experimental treatment of animals with ER stress inhibitors alleviated renal damage. Considering these findings, the normalization of ER stress by pharmacological agents is a promising approach to prevent or arrest DN progression. The current article reviews the mechanisms, roles, and therapeutic aspects of these findings.

Adiponectin agonist treatment in diabetic pregnant rats

Gestational diabetes mellitus (GDM) reduces maternal adiponectin and docosahexaenoic acid (DHA) materno-fetal transfer, which may have negative consequences for the offspring. Our aim was to evaluate the effects of the administration of a novel adiponectin agonist (AdipoRon) to GDM rats on the long-term consequences in glycaemia and fatty acids (FA) profile in the offspring. Pregnant rats were randomized to three groups: GDM rats (GDM, n = 8), GDM rats treated with AdipoRon (GDM + ADI, n = 9), and control rats (n = 10). Diabetes was induced with streptozotocin (50 mg/kg) on day 12 of gestation. GDM+ADI received 50 mg/kg/day AdipoRon from day 14 until delivery. Glycaemia and FA profile were determined in mothers and adult offspring (12 weeks old). AdipoRon tended to reduce fasting glucose in diabetic mothers. Diabetic rats presented the foetus with intrauterine growth restriction and higher adiposity, which tried to be counteracted by AdipoRon. In the adult offspring, both GDM + ADI and control animals showed better glucose recovery after oral glucose overload with respect to GDM. DHA in offspring plasma was significantly reduced in both GDM and GDM + ADI compared to controls (P = 0.043). Nevertheless, n-6/n-3 polyunsaturated FA (PUFA) ratio improved in plasma of GDM + ADI adult offspring (GDM: 14.83 ± 0.85a%; GDM + ADI: 11.49 ± 0.58b%; control: 10.03 ± 1.22b%, P = 0.034). Inflammatory markers and oxidative stress were reduced in the adult offspring of AdipoRon-treated mothers. In conclusion, AdipoRon administration to pregnant diabetic rats improved glycaemia in the mothers and long-term glucose tolerance in the offspring. In addition, it tended to reduce excessive foetal fat accumulation and improved n-6/n-3 PUFA ratio significantly in offspring at the adult state.