Endoplasmic reticulum stress contributes to cisplatin-induced chronic kidney disease via the PERK-PKCδ pathway.

BACKGROUND: Cisplatin is an effective chemotherapeutic drug, but it may induce both acute and chronic kidney problems. The pathogenesis of chronic kidney disease (CKD) associated with cisplatin chemotherapy remains largely unclear. METHODS: Mice and renal tubular cells were subjected to repeated low-dose cisplatin (RLDC) treatment to induce CKD and related pathological changes. The roles of endoplasmic reticulum (ER) stress, PERK, and protein kinase C-δ (PKCδ) were determined using pharmacological inhibitors and genetic manipulation. RESULTS: ER stress was induced by RLDC in kidney tubular cells in both in vivo and in vitro models. ER stress inhibitors given immediately after RLDC attenuated kidney dysfunction, tubular atrophy, kidney fibrosis, and inflammation in mice. In cultured renal proximal tubular cells, inhibitors of ER stress or its signaling kinase PERK also suppressed RLDC-induced fibrotic changes and the expression of inflammatory cytokines. Interestingly, RLDC-induced PKCδ activation, which was blocked by ER stress or PERK inhibitors, suggesting PKCδ may act downstream of PERK. Indeed, suppression of PKCδ with a kinase-dead PKCδ (PKCδ-KD) or Pkcδ-shRNA attenuated RLDC-induced fibrotic and inflammatory changes. Moreover, the expression of active PKCδ-catalytic fragment (PKCδ-CF) diminished the beneficial effects of PERK inhibitor in RLDC-treated cells. Co-immunoprecipitation assay further suggested PERK binding to PKCδ. CONCLUSION: These results indicate that ER stress contributes to chronic kidney pathologies following cisplatin chemotherapy via the PERK-PKCδ pathway.

Evaluation of acute and chronic nephrotoxicity in patients received cisplatin-based chemotherapy: has anything changed over time?

PURPOSE: The aim of this study was to determine the frequency and the risk factors of acute and chronic nephrotoxicity in patients who received cisplatin due to malignancy. MATERIALS AND METHODS: Medical records of all patients who received cisplatin-based chemotherapy regimen between January 2013 and July 2019 were retrospectively evaluated. The data of 203 patients who met the study criteria were examined. The patients were evaluated for acute nephrotoxicity at 48 h and late nephrotoxicity at 3rd month after first course of cisplatin. Early and late nephrotoxicity were defined by NCI CTCAE Version 4.0 criteria. RESULTS: The mean age of the study patients was 56.44 ± 12.69 years, 78.8% were males and 21.2% were females. It is revealed that the incidence of cisplatin-induced acute nephrotoxicity was 9.2% and chronic nephrotoxicity was 37.9%. While the development of acute nephrotoxicity was associated with female gender, history of diabetes mellitus, history of ischemic heart disease and use of antiplatelet drug, the development of chronic nephrotoxicity was associated with older age, female gender and using of diuretics. High serum creatinine, urea and low eGFR value before treatment were found to be associated with both early and late nephrotoxicity (p < 0.05). There was no statistically significant relationship between acute or chronic nephrotoxicity and cumulative dose of cisplatin, hydration or intravenous magnesium supplementation. CONCLUSION: High initial serum creatinine value and low initial eGFR are the most important determinants of both early and late nephrotoxicity.

Astragalus membranaceus and Salvia miltiorrhiza ameliorates cyclosporin A-induced chronic nephrotoxicity through the "gut-kidney axis".

ETHNOPHARMACOLOGICAL RELEVANCE: The combination of Astragalus membranaceus and Salvia miltiorrhiza (AS) is an effective prescription that is widely used to treat chronic kidney disease (CKD) clinically in traditional Chinese medicine. Our previous studies have shown that AS can alleviate early CKD through the "gut-kidney axis", but the regulatory role of AS in the "gut-kidney axis" in the middle and late stages of CKD caused by cyclosporin A-induced chronic nephrotoxicity (CICN) has remained unclear. AIM OF THE STUDY: To explore the protective effect of AS by regulating the intestinal flora to further control the miRNA-mRNA interaction profiles in CICN. MATERIALS AND METHODS: Thirty-two mice were divided into four groups: Normal (N) (olive oil), Model (M) (CsA, 30 mg kg-1 d-1), AS (CsA + AS, 30 + 8.4 g kg-1 d-1) and FMT-AS (CsA + Faeces of AS group, 30 mg + 10 mL kg-1 d-1). The mice were treated for 6 weeks. Changes in renal function related metabolites were detected, pathological changes in the colon and kidney were observed, and 16S rDNA sequencing was performed on mouse faeces. In addition, miRNA and mRNA sequencing were performed on the kidney to construct differential expression (DE) profiles of the other 3 groups compared with group M. The target mRNAs among the DE miRNAs were then predicted, and an integrated analysis was performed with the DE mRNAs to annotate gene function by KEGG. DE miRNAs and DE mRNAs related to CICN in the overlapping top 20 KEGG pathways were screened and verified. RESULTS: Eight metabolites that could worsen renal function were increased in group M, accompanied by thickening of the glomerular basement membrane, vacuolar degeneration of renal tubules, and proliferation of collagen fibres, while AS and FMT-AS intervention amended these changes to varying degrees. Simultaneously, intestinal permeability increased, the abundance and diversity of the flora decreased, and the ratio of Firmicum to Bacteroides (F/B) increased in group M. The AS and FMT-AS treatments reversed the flora disorder and increased probiotics producing butyric acid and lactic acid, especially Akkermansia and Lactobacillus, which might regulate the 12 overlapping top 20 KEGG pathways, such as Butanoate metabolism, Tryptophan metabolism and several RF-related pathways, leading to the remission of renal metabolism. Finally, 15 DE miRNAs and 45 DE mRNAs were screened as the therapeutic targets, and the results coincided with the sequencing results. CONCLUSION: AS could alleviate renal fibrosis and metabolism caused by CICN through the "gut-kidney axis". Probiotics such as Akkermansia and Lactobacillus were the primary driving factors, and the miRNA-mRNA interaction profiles, especially Butanoate metabolism and Tryptophan metabolism, may be an important subsequent response and regulatory mechanism.

Astragaloside IV Alleviates Tacrolimus-Induced Chronic Nephrotoxicity via p62-Keap1-Nrf2 Pathway.

Tacrolimus-induced chronic nephrotoxicity (TIN) hinders its long-term use in patients. However, there are no drugs available in the clinic to relieve it at present. Astragaloside IV (AS-IV) is a saponin extract of the Astragalus which is widely used in the treatment of kidney disease. This study aimed to investigate the effect of AS-IV on TIN and its underlying mechanism. Herein, C57BL/6 mice were treated with tacrolimus and/or AS-IV for 4 weeks, and then the renal function, fibrosis, oxidative stress and p62-Keap1-Nrf2 pathway were evaluated to ascertain the contribution of AS-IV and p62-Keap1-Nrf2 pathway to TIN. Our results demonstrated that AS-IV significantly improved renal function and alleviated tubulointerstitial fibrosis compared with the model group. The expression of fibrosis-related proteins, including TGF-ß1, Collagen I and α-SMA, were also decreased by AS-IV. Furthermore, AS-IV relieved the inhibition of tacrolimus on antioxidant enzymes. The data in HK-2 cells also proved that AS-IV reduced tacrolimus-induced cell death and oxidative stress. Mechanistically, AS-IV markedly promoted the nuclear translocation of Nrf2 and the renal protective effects of AS-IV were abolished by Nrf2 inhibitor. Further researches showed that phosphorylated p62 was significantly increased after AS-IV pretreatment. Moreover, AS-IV failed to increase nuclear translocation of Nrf2 and subsequent anti-oxidative stress in HK-2 cells transfected with p62 siRNA. Collectively, these findings indicate that AS-IV relieve TIN by enhancing p62 phosphorylation, thereby increasing Nrf2 nuclear translocation, and then alleviating ROS accumulation and renal fibrosis.

Olmesartan protects against oxidative stress possibly through the Nrf2 signaling pathway and inhibits inflammation in daunorubicin-induced nephrotoxicity in rats.

Anthracycline anticancer drug daunorubicin (DNR) can induce chronic nephrotoxicity, which is believed to be based on oxidative injury. Olmesartan has significant blood pressure lowering effect via modulating renin-angiotensin system although its mechanism of action in DNR-induced renal injury is largely unknown. Transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular oxidative stress. This study examined the role of Nrf2 in olmesartan-mediated antioxidant effects in DNR induced kidney cells. In addition, key factors involved in promoting inflammation and oxidative stress were studied. Sprague-Dawley rats were treated with a cumulative dose of 9 mg/kg DNR (i.v.). Olmesartan was administered orally every day for 6 weeks. DNR treated rats showed nephrotoxicity as evidenced by worsening renal function, which was evaluated by measuring total cholesterol, triglyceride levels in kidney tissue and histopathological approaches; treatment with olmesartan reversed these changes. Furthermore, olmesartan treatment down-regulated phospho-MAPKAPK-2, caspase-12, p47(phox), p67(phox), upregulated renal expression of PPAR-γ, Bcl-xL, glutathione peroxidase and Nrf2. Furthermore, olmesartan down-regulated matrix metalloproteinase-2 and angiotensin II type I receptor expression in the kidney. In conclusion, the result demonstrated that angiotensin II and oxidative stress play a key role in DNR-induced nephrotoxicity. The present results indicated that olmesartan protects against oxidative stress, which may be possibly via the induction of Nrf2 signaling pathways.

The over-exaggerated chronic nephrotoxicity of calcineurin inhibitors.

BACKGROUND: Late kidney allograft failure remains a major problem in kidney transplantation. While there is no doubt that acute nephrotoxicity from calcineurin inhibitors (CNIs) exists, chronic CNI nephrotoxicity has been the subject of much debate in the transplant community. METHODS: We identified original articles related to the use of CNIs in renal and extra-renal solid-organ transplantation, to examine the available evidence about their chronic nephrotoxicity. RESULTS: There is clearly a lack of firm evidence for the role of CNIs as a major injurious agent causing chronic renal dysfunction and allograft failure. Moreover, recent evidence shows that the pathological lesions typically linked to chronic CNI use are not specific. A growing body of evidence shows that alloimmunity is a much more important cause of late renal allograft failure. CONCLUSIONS: More research should focus on addressing the true causes of chronic graft dysfunction rather than continuing to propagate the exaggerated contribution of CNIs to late graft loss.