Lower limb arterial thrombosis in an adult with membranous glomerulonephritis.

Massive proteinuria and hypoalbuminemia are potential risk factors in thromboembolic complications. Venous thrombosis is a frequent complication of thromboembolism in patients with membranous glomerulonephritis, while arterial thrombosis is much less reported. A 35-year-old man presented with nephrotic syndrome and osteofascial compartment syndrome in the right lower limb due to arterial thrombosis. The biopsy findings were consistent with those of stage 2 membranous nephropathy. After immunotherapy (steroids and cyclosporine), the massive proteinuria, renal function, and serum albumin improved markedly. This is the first case of adult membranous glomerulonephritis with unilateral lower extremity arterial thrombosis diagnosed by renal biopsy and arteriography. It further confirms the high incidence of thromboembolic complications with membranous nephropathy.

Gasdermin D Protects Mouse Podocytes Against High-Glucose-Induced Inflammation and Apoptosis via the C-Jun N-Terminal Kinase (JNK) Pathway.

BACKGROUND The inflammation and apoptosis of podocytes contribute to the pathological progression of diabetic nephropathy. Gasdermin D (GSDMD) plays an executive role in pyroptosis, but its effect on high-glucose (HG)-induced inflammation and apoptosis remains unclear. The aim of this study was to investigate the effect of GSDMD on high-glucose-induced inflammation and apoptosis in podocytes. MATERIAL AND METHODS Mouse podocytes were cultivated by high- or normal-glucose medium. We used western blot analysis, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and immunofluorescence to detect the expression and localization of GSDMD in high-glucose-induced podocytes, and the expression of apoptosis-related proteins Bax and Bcl-2, inflammatory factors IL-1ß, IL-6, and TNF-alpha, and JNK pathways in high-glucose-induced podocytes. Western blot and immunofluorescence were used to detect the expression and localization of synaptopodin under GSDMD knockdown and JNK-specific blocker SP600125. MitoSOX Red was used to detect the production of ROS in mitochondria under siGSDMD. The intracellular ROS generation was detected using a reactive oxygen species assay kit. RESULTS We found that GSDMD knockdown and JNK inhibition reduced the expression of Bax, Bcl-2, cleaved caspase-3, IL-1ß, IL-6, and TNF-alpha. Our results showed that GSDMD knockdown can inhibit HG-induced mitochondrial ROS production and JNK phosphorylation. CONCLUSIONS This study indicates that GSDMD knockdown can attenuate HG-induced inflammation and apoptosis by inhibiting the phosphorylation of JNK via mitochondrial ROS.

Carnosine Protects Mouse Podocytes from High Glucose Induced Apoptosis through PI3K/AKT and Nrf2 Pathways.

Diabetic nephropathy is the complication of diabetes mellitus that can lead to chronic renal failure. Reactive oxygen species (ROS) production plays an important role in its pathological process. Previous studies showed that carnosine may reduce diabetic nephropathy by antioxidant effect. However, the molecular mechanism of its antioxidant was not fully understood. In the current study, we developed high glucose containing different concentrations of carnosine to reduce ROS levels and podocytes apoptosis, and Cell Counting Kit-8 test was used to observe the cell viability. Carnosine (5-20mM) was found to protect mouse podocytes (MPC5) cells from HG-induced injury. Quantitative real-time PCR, Western blotting, and immunofluorescence staining revealed that high glucose induced ROS levels and podocytes apoptosis were downregulated by PI3K/AKT and Nrf2 signaling pathways. The current findings suggest that carnosine may reduce ROS levels and MPC5 cells apoptosis by PI3K/AKT and Nrf2 signaling pathways activation.

Protective effects of pyrroloquinoline quinine against oxidative stress-induced cellular senescence and inflammation in human renal tubular epithelial cells via Keap1/Nrf2 signaling pathway.

Oxidative stress-induced cellular senescence and inflammation are important biological events in diabetic nephropathy (DN). Our recent studies have found that pyrroloquinoline quinine (PQQ) has protective effects against HG-induced oxidative stress damage and apoptosis in HK-2 cells. Nevertheless, whether PPQ has the effect of anti-inflammation and anti-senescence in HK-2 cells remains unclear. Here, we showed that low-dose PPQ treatment (100 nM) downregulates the expression of P16, P21, IL-1ß, TNF-α and NF-κB in HG cultured HK-2 cells. A low dose of PPQ also upregulated the protein expression of SOD2, CAT and inhibited the generation of ROS. We also indicated that PPQ affected the activity of Keap1/Nrf2 pathway, increased the nuclear accumulation of Nrf2 and the downstream pathway protein expression of Keap1/Nrf2 signaling pathway (HO-1, NQO-1, GST and GPx-3). When ML385 was added to inhibit the activity of Keap1/Nrf2 signaling pathway, the effects of PPQ on anti-oxidative stress, anti-inflammation and anti-senescence in HK-2 cells under HG condition were weakened. In conclusion, our results suggest that PPQ could modulate HG-induced inflammation and senescence in HK-2 cells via the inhibition of ROS generation and achieves the protective effects through Keap1/Nrf2 pathway and upregulating the expression of its target protein.

Pyridoxamine Treatment of HK-2 Human Proximal Tubular Epithelial Cells Reduces Oxidative Stress and the Inhibition of Autophagy Induced by High Glucose Levels.

BACKGROUND Diabetic nephropathy is a predominant cause of renal failure, which is an important chronic complication of diabetes. Pyridoxamine (PM) has been reported to protect renal tubular epithelial cells against oxidative damage and delay or inhibit the development and generation of glucose-induced renal insufficiency at the early stage of disease. In this study, we attempted to explore the protection mechanism of PM on human proximal tubular epithelial cells (HK-2 cells) induced by high glucose. MATERIAL AND METHODS HK-2 cells were cultivated by high glucose medium in the absence or presence of PM. Cell Counting Kit-8 was used to investigate the most appropriate drug concentration of PM by detecting the cell viability of HK-2 cells. The expression of autophagy-related protein Beclin-1, LC-3II, and p62 was measured by western blot analysis, reverse transcription­quantitative polymerase chain reaction (RT­qPCR), and immunofluorescence. The expression and localization of Beclin-1 and p62 were also detected via immunofluorescence. The intracellular reactive oxygen species generation was detected using the reactive oxygen species assay kit. The effects of PM on antioxidant defenses were evaluated with glutathione peroxidase (GPx), manganese superoxide dismutase (MnSOD) activity, and glutathione/glutathione disulfide (GSH/GSSG) ratio. RESULTS High glucose levels were able to upregulate the expression of oxidative stress associated protein and inhibit autophagy­associated changes verified by western blotting, RT­qPCR and immunofluorescence. Administration of PM reversed the high glucose­induced low-expressed Beclin-1 and LC-3II, and overexpressed p62 and intracellular reactive oxygen species levels. Furthermore, non-enzymatic antioxidant defenses and enzymatic antioxidant defenses were turned on by the application of PM. CONCLUSIONS Treatment with PM could reverse high glucose-induced inhibition of autophagy and oxidative stress.

Pyrroloquinoline quinine protects HK-2 cells against high glucose-induced oxidative stress and apoptosis through Sirt3 and PI3K/Akt/FoxO3a signaling pathway.

High glucose(HG)-induced oxidative stress and apoptosis in renal tubular epithelial cells play an important role in the pathogenesis of diabetic nephropathy. Pyrroloquinoline quinine (PQQ), a new B vitamin, has been demonstrated to be important in antioxidant and anti-apoptotic effects. However, its effect on HK-2 cells and the potential mechanism are rarely investigated. In this study, we investigated that PPQ had protective effects against HG-induced oxidative stress damage and apoptosis in vitro model of diabetic nephropathy. PPQ at 10, 100, 500, 1000 and 10000 nM could protect HK-2 cell from HG-induced inhibition. The protective effects of PQQ were associated with increasing the level of antioxidants(SOD2, CAT), inhibition of reactive oxygen species(ROS) production, and dependent modulation of Bcl-2 family proteins. PPQ significantly upregulated the protein and mRNA expression of Sirtuin3(Sirt3) in HG-induced HK-2 cells. PPQ also reduced apoptosis in HG-induced HK-2 cells by the PI3K/Akt/FoxO3a signal pathway. As down-regulated sirt3 or inhibitory the activity of PI3K/Akt/FoxO3a pathway, the protective effects of PPQ were weakened. In conclusion, our data suggest that PPQ achieves the protective effects through PI3K/Akt/FoxO3a pathway and dependent modulation of Sirt3.