Diabetic kidney disease (DKD) is one of the microvascular complications of diabetes mellitus and a major cause of end-stage renal disease with limited treatment options. Wogonin is a flavonoid derived from the root of Scutellaria baicalensis Georgi, which has shown a potent renoprotective effect. But the mechanisms of action in DKD are not fully elucidated. In this study, we investigated the effects of wogonin on glomerular podocytes in DKD using mouse podocyte clone 5 (MPC5) cells and diabetic mice model. MPC5 cells were treated with high glucose (30 mM). We showed that wogonin (4, 8, 16 μM) dose-dependently alleviated high glucose (HG)-induced MPC5 cell damage, accompanied by increased expression of WT-1, nephrin, and podocin proteins, and decreased expression of TNF-α, MCP-1, IL-1β as well as phosphorylated p65. Furthermore, wogonin treatment significantly inhibited HG-induced apoptosis in MPC5 cells. Wogonin reversed HG-suppressed autophagy in MPC5 cells, evidenced by increased ATG7, LC3-II, and Beclin-1 protein, and decreased p62 protein. We demonstrated that wogonin directly bound to Bcl-2 in MPC5 cells. In HG-treated MPC5 cells, knockdown of Bcl-2 abolished the beneficial effects of wogonin, whereas overexpression of Bcl-2 mimicked the protective effects of wogonin. Interestingly, we found that the expression of Bcl-2 was significantly decreased in biopsy renal tissue of diabetic nephropathy patients. In vivo experiments were conducted in STZ-induced diabetic mice, which were administered wogonin (10, 20, 40 mg · kg⁻¹ · d⁻¹, i.g.) every other day for 12 weeks. We showed that wogonin administration significantly alleviated albuminuria, histopathological lesions, and p65 NF-κB-mediated renal inflammatory response. Wogonin administration dose-dependently inhibited podocyte apoptosis and promoted podocyte autophagy in STZ-induced diabetic mice. This study for the first time demonstrates a novel action of wogonin in mitigating glomerulopathy and podocytes injury by regulating Bcl-2-mediated crosstalk between autophagy and apoptosis. Wogonin may be a potential therapeutic drug against DKD.

Toll-like receptors (TLRs) may be involved in diabetic nephropathy (DN). Paeoniflorin (PF) is an effective Chinese traditional medicine with anti-inflammatory and immunoregulatory effects that may inhibit the TLR2 signaling pathway. In this study, we investigated the effects of PF on the kidneys of mice with streptozotocin-induced type 1 diabetes mellitus using TLR2 knockout mice (TLR2^-/-) and wild-type littermates (C57BL/6J-WT). After 12 weeks of intraperitoneal injection of PF at doses of 25, 50, and 100 mg/kg once a day, diabetic mice had significantly reduced albuminuria and attenuated renal histopathology. These changes were associated with substantially alleviated macrophage infiltration and decreased expression of TLR2 signaling pathway biomarkers. These data support a role of TLR2 in promoting inflammation and indicate that the effect of PF is associated with the inhibition of the TLR2 pathway in the kidneys of diabetic mice. PF thus shows therapeutic potential for the prevention and treatment of DN.

Background: Growing evidence has demonstrated that patients undergoing peritoneal dialysis (PD) are more likely to experience cognitive impairment than patients with non-dialysis end-stage renal disease (ESRD); however, the underlying mechanisms remain unclear. This study aimed to identify the role and predictive significance of gut microbiome alterations in PD-associated cognitive impairment. Methods: A total of 29 non-dialysis ESRD patients and 28 PD patients were enrolled in this study and divided into subgroups according to the Montreal Cognitive Assessment (MoCA). Faecal samples were analyzed using 16 S rRNA. Mini-Mental State Examination (MMSE) and MoCA scores were used to assess the degree of cognitive impairment in patients. Results: The 16 S rRNA analysis demonstrated differences in gut microbiome abundance and structure between PD and non-dialysis ESRD patients and between PD patients with cognitive impairment (PCI) and PD patients with normal cognition (PNCI). At family and genus levels, Prevotellaceae exhibited the greatest structure difference, while Lactobacillus exhibited the greatest abundance difference between PCI and PNCI. Altered microbiota abundance significantly correlated with cognitive function and serum indicators in PD. In addition, different modules related to fatty acid, lipid, pantothenate, and coenzyme A biosynthesis, and tyrosine and tryptophan metabolism were inferred from 16 S rRNA data between PCI and PNCI. Both groups could be distinguished using models based on the abundance of Lactobacillaceae (Area under curve [AUC] = 0.83), Actinomycetaceae (AUC = 0.798), and Prevotellaceae (AUC = 0.778) families and Lactobacillus (AUC = 0.848) and Actinomyces (AUC = 0.798) genera. Conclusion: Gut microbiome evaluation could aid early cognitive impairment diagnosis in patients undergoing PD.

Necroptosis was elevated in both tubulointerstitial and glomerular renal tissue in patients with diabetic kidney disease (DKD), and was most pronounced on glomerulus in the stage with macroalbuminuria. This study further explored whether paeoniflorin (PF) could affect podocyte necroptosis to protect kidney injure in vivo and in vitro. Our study firstly verified that there are obvious necroptosis-related changes in the glomeruli of DKD through bioinformatics analysis combined with clinicopathological data. STZ-induced mouse diabetes model and high-glucose induced podocyte injury model were used to evaluate the renoprotection, podocyte injury protection and necroptosis regulation of PF in DKD. Subsequently, the target protein-TNFR1 that PF acted on podocytes was found by computer target prediction, and then molecular docking and Surface plasmon resonance (SPR) experiments were performed to verify that PF had the ability to directly bind to TNFR1 protein. Finally, knockdown of TNFR1 on podocytes in vitro verified that PF mainly regulated the programmed necrosis of podocytes induced by high glucose through TNFR1. In conclusion, PF can directly bind and promote the degradation of TNFR1 in podocytes and then regulate the RIPK1/RIPK3 signaling pathway to affect necroptosis, thus preventing podocyte injury in DKD. Thus, TNFR1 may be used as a new potential target to treat DKD.

Objective: To investigate the effect of TGF-β activated kinase-1(TAK1) inhibitor 5Z-7-oxozeaenol on the interaction between macrophages and mesangial cells exposed to high glucose. Methods: The macrophages and mesangial cells were cultured separately or co-cultured and divided into seven groups: inhibitor control group, mannitol control group, normal control group, high glucose group and inhibitor groups. The expression of p-TAK1, TAK1 binding protein (TAB1), transcription factor NF - κ B (NF-κB p65) of macrophages were analyzed by Western blotting. The intracellular localization of NF-κB p65 was analyzed by immunofluorescence. The levels of inflammation cytokines and extracellular matrix were determined by enzyme-linked immune sorbent assay. Migration of macrophages was observed by microscope. Results: Compared with control group, the expression of p-TAK1, TAB1, NF-κB p65 were significantly higher in high glucose group (P < 0.05). Both in co-culture group and single culture group, the levels of inflammation cytokines and extracellular matrix (P < 0.05) in high glucose group were higher than that in control group. Exposed to high glucose, the levels of inflammation cytokines and extracellular matrix in co-cultured group were higher than that in single culture group (P < 0.05). 5Z-7-oxozeaenol can decrease those cytokines secretion, comparing with high glucose group (P < 0.05). The number of macrophages migration were decreased by 5Z-7-oxozeaenol (P < 0.05). Conclusion: Exposed to high glucose, macrophages and mesangial cells can interact with each other to promote the secretion of inflammation cytokines and extracellular matrix. TAK1 inhibitor can reduce the secretion of inflammation cytokines and extracellular matrix components by intervening NF-κB p65 nuclear transfer and inhibiting macrophage migration.