Cassia auriculata leaf extract ameliorates diabetic nephropathy by attenuating autophagic necroptosis via RIP‐1/RIP‐3‐p‐p38MAPK signaling

Abstract

Diabetic nephropathy (DN) is the most common manifestation of high glucose induced diabetes mellitus. In this study, we report the effects of Cassia auriculata ethanol leaf extract (CALE) on DN‐associated cell toxicity and complications. The effects of CALE were screened in vitro using RGE cells. Cell viability was assessed using MTT and flow cytometry. Male Sprague‐Dawley rats were divided into control, DN and treatment groups (n = 8). The DN and treatment groups received 60 mg/kg/bw of streptozotocin in citrate buffer, while the treatment group was administered 150 mg/kg/bw of CALE for 10 weeks. Biochemical analysis was conducted using spectrophotometry. Kidney tissues were analyzed using hematoxylin and eosin staining and transmission electron microscopy. CD365‐KIM‐1 expression was assessed using flow cytometry and signalling proteins were detected using western blotting. Treatment with 30‐mM glucose reduced the viability of RGE cells in a time‐dependent manner and increased the population of dead RGE cells. Cotreatment with CALE reduced cell death and glucose induced protein expression of LC3‐II, RIP‐1 and RIP‐3 in a dose‐dependent manner. In addition, CALE improved the biochemical complications, renal dysfunction and pathophysiology of rats with DN and partially or fully restored the expression of key DN‐associated signalling proteins, such as KIM‐1 LC3‐II, RIP‐1, RIP‐3 and p‐p38MAPK in kidney cells. CALE showed protective effects, and improved DN‐associated complications in RGE cells under high glucose stress conditions, potentially by inhibiting autophagic‐necroptosis signals. Additionally, CALE improved the biochemical and pathological features of kidney injury while reducing autophagic‐necroptosis in rat renal cells via the LC3‐II‐RIP‐p38MAPK pathway. Practical applications Results from the current investigation will add information to the literature on glucose induced renal toxicity and the protective effects of CALE over the complications of diabetic nephropathy (DN). The mechanistic investigations of the study will add light on the autophagic/necroptosis signals in DN and open new routes of investigations to study the efficacy of CALE in diabetes‐related complications.

USP22 Mediates High Glucose-Induced Injury and Epithelial-Mesenchymal Transition in Podocytes via Regulating the RIPK3/MLKL Signaling Pathway

“…Xu et al found that upregulation of UCHL1 in podocytes of DN patients increased the de-ubiquitination of RIPK1 and RIPK3, thereby facilitating the necroptosis of podocytes 25) . Shahrani et al also demonstrated that necroptosis was involved in podocyte injury induced by HG in vitro 11) , which is consistent with the results of the present study. Except for cell injury, detachment is considered as another contributor to the decrease of podocyte density 26) .…”

“…Recently, USP22 was demonstrated to drive necroptotic cell death by reducing RIPK3 ubiquitination 10) . Importantly, a growing number of studies over the last decade found that necroptosis was observed in DN 11,12) . In addition, multiple experimental data suggested that USP22 plays a regulatory role in DN progression, which may be a promising target for DN 13,14) .…”

The role of necroptosis in disease and treatment

“…Moreover, the traditional Chinese medicine drugs could inhibit necroptosis such as aucubin, 221 wogonin, 222 patchouli alcohol, 223 and cassia auriculata leaf extract. 224 In conclusion, drugs and agents that inhibit necroptosis or the expression of RIPK1, RIPK3, and MLKL may have therapeutic potential for human disease.…”