Restoration of E-cadherin by compound 8J protects against cisplatin-induced acute kidney injury by attenuating inflammation and programmed cell death

OBJECTIVE E-cadherin is a major component of tubular adherent proteins which maintain intercellular contacts and cell polarity in epithelial tissue,it is involved in the pathological process of renal cell carcinoma and fibrotic diseases via epithelial-mesenchymal transition.Although we and others found that expression of E-cadherin was significantly down-regulated in kidney suffered acute kidney injury(AKI),its function in AKI was still unknown,which was explored in the current study.METHODS We disrupted E-cadherin or restored E-cadherin with compound 8J in cisplatin-stimulated tubular epithelial cell lines,the cell damage and inflammation were evaluated,additionally,the therapeutic potential of E-cadherin restoration was also determined in vivo.RESULTS We found that cisplatin reduced E-cadherin expression both in mouse kidney and tubular epithelial cell lines(m TECs).Administration of compound 8J restored the level of E-cadherin,thereby increased cell viability while attenuating programmed cell death,which may be mediated by deactivation of RIPK/MLKL axis,reduced membrane translocation of phosphor-MLKL and decreased cleavage of caspase 3.Compound 8J also suppressed inflammatory response in cisplatin-treated m TECs,which was correlated with suppressed NF-κB phorsphorylation and promoter activity.In contrast,disruption of E-cadherin enhanced cell damage and inflammation.Treatment of compound 8J failed to further attenuate kidney damage in E-cadherin knockdown cells,indicating compound 8J protected against mT ECs mainly through restoring E-cadherin.We also found that peritoneal injection of compound 8J protected against renal function and tubular damage by preventing NF-κB-driven renal inflammation and RIPK/MLKL-regulated programmed cell death,which was led by restoration of E-cadherin in cisplatin nephropathy.CONCLUSION More than a victim degraded after kidney injury,E-cadherin also has functional role in controlling tubule integrity,programmed cel death and renal inflammation.In this regard,restoration of E-cadherin by compound 8J should be considered as a novel therapeutic strategy for acute kidney injury.

Alcohol promotes renal fibrosis by activating Nox-mediated DNA methylation of Smad7

OBJECTIVE Alcohol is mainly metabolized through liver and excreted by kidney in the body.Kidney damage has been considered as the secondary to liver injury and kidney dysfunction is common in hospitalized patients with severe alcoholic hepatitis.Both acute and chronic alcoholism accumulation can compromise kidney function,although alcoholic kidney disease has drawn much more attention recently,the methodology for establishing the in vivo and in vitro alcoholic renal fibrosis models are still lacking,and the underlying mechanisms are to be determined.METHODS and RESULTS Mice were feed with a liquid diet containing alcohol for 4 weeks,8 weeks and 12 weeks respectively,results of Masson′ s Trichrome staining showed that kidney fibrosis peaked in 8-week model group,which consistent with the results of albumin assay,Western blot,immunostaining and real-time PCR of collagen I and α-SMA.In vitro study also confirmed that ethanol upregulated the level of fibrotic index.es,including collagen I and α-SMA,in tubular epithelial cells(HK2 cells).Additionally,both in vivo and in vitro studies showed that Smad7 was decreased and Smad3 was highly activated.Then we further detected the underlying mechanisms by which alcohol induced the imbalance of Smad7 and Smad3.Results of Genome-wide methylation sequencing found DNA methylation of Smad7 in the alcoholic fibrosis kidney,which may be mainly mediated by DNA methyltransferase 1(DNMT1),because knock.down of DNMT1,but not DNMT2 and 3,largely restored Smad7 level in ethanol-treated HK2 cells.Con.sequently,we found that NADPH Oxidases(nox)-mediated oxidative stress is the major force upregu.lating DNMT1,since knockdown of Nox2 and 4 could both decrease DNMT1 while rebalancing Smad7/Smad3 axis,and thereby relieved ethanol-induced fibrotic response in HK2 cells.More importantly,intraperitoneal injection of apocynin,an inhibitor of NADPH oxidoreductase,attenuated renal fibrosis in alcoholic kidney fibrosis mouse model.CONCLUSION By establishing the novel in vivo and in vitro models,we found that through activating oxidative stress-induced DNA methylation of Smad7,alcohol induces renal fibrosis by breaking the balance between Smad7 and Smad3.Elimination of Nox-mediated oxidative stress may be a potential therapy for treatment of long-term alcohol abuse-induced kidney fibrosis.

Potential targeted therapy and diagnosis based on novel insight into growth factors,receptors,and downstream effectors in acute kidney injury and acute kidney injury-chronic kidney disease progression

Acute kidney injury(AKI)is defined as a rapid decline in renal function and is characterized by excessive renal inflammation and programmed death of resident cells.AKI shows high morbidity and mortality,and severe or repeated AKI can transition to chronic kidney disease(CKD)or even end-stage renal disease(ESRD);however,very few effective and specific therapies are available,except for supportive treatment.Growth factors,such as epidermal growth factor(EGF),insulin-like growth factor(IGF),and transforming growth factor-β(TGF-β),are significantly altered in AKI models and have been suggested to play critical roles in the repair process of AKI because of their roles in cell regeneration and renal repair.In recent years,a series of studies have shown evidence that growth factors,receptors,and downstream effectors may be highly involved in the mechanism of AKI and may function in the early stage of AKI in response to stimuli by regulating inflammation and programmed cell death.Moreover,certain growth factors or correlated proteins act as biomarkers for AKI due to their sensitivity and specificity.Furthermore,growth factors originating from mesenchymal stem cells(MSCs)via paracrine signaling or extracellular vesicles recruit leukocytes or repair intrinsic cells and may participate in AKI repair or the AKI-CKD transition.In addition,growth factor-modified MSCs show superior therapeutic potential compared to that of unmodified controls.In this review,we summarized the current therapeutic and diagnostic strategies targeting growth factors to treat AKI in clinical trials.We also evaluated the possibilities of other growth factorcorrelated molecules as therapeutic targets in the treatment of AKI and the AKI-CKD transition.