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MLKL is a central mediator for necroptosis. Its knockout significantly relieves acute kidney injury (AKI). However, its upstream regulatory mechanism in AKI has not been fully elucidated. We recently reviewed how microRNAs (miRNAs), a type of well‐studied epigenetic regulator, play critical roles in AKI. Here, we evaluated miRNAs that potentially target MLKL and evaluated their function in human tubular epithelial cells in response to toxic and ischemic insults. TargetScan analysis showed that miR‐194‐5P, miR‐338‐3P, miR‐500a‐3P, and miR‐577 had MLKL binding sites. Although all 4 miRNAs are reduced in AKI, our data show that only hsa‐miR‐500a‐3P was significantly suppressed in cisplatin‐treated human tubular epithelial (HK2) cells. We further found that hsa‐miR‐500a‐3P alleviated cisplatin‐induced HK2 cell death, which was confirmed by transmission electron microscopy and flow cytometry. In addition, overexpression of hsa‐miR‐500a‐3P decreased kidney injury molecule‐1 mRNA and protein levels. Real‐time PCR, ELISA, and immunofluorescence data show that hsa‐miR‐500a‐3P protected against inflammatory response, evidenced by decreased monocyte chemotactic protein‐1 and proinflammatory cytokines TNF‐α and IL‐8. Further, hsa‐miR‐500a‐3P attenuated P65 NF‐κB phosphorylation and promoter activity. Mechanistically, luciferase reporter assay showed that hsa‐miR‐500a‐3P bound the 3′UTR of MLKL, thereby suppressing phosphorylation and membrane translocation of MLKL. In agreement with these findings, we identified that overexpression of hsa‐miR‐500a‐3P attenuated cell injury and the inflammatory response in response to sodium azide treatment in an in vitro model. Results show that circulating exosomes from patients with AKI down‐regulated miR‐500a‐3P, which suppressed cell injury and inflammation in HK2 cells. hsa‐miR‐500a‐3P alleviated toxic and ischemic insults that were triggered by cell necroptosis and the inflammatory response in human HK2 cells by targeting MLKL. This may serve as a novel therapeutic target for treatment of AKI.—Jiang, L., Liu, X.‐Q., Ma, Q., Yang, Q., Gao, L., Li, H.‐D., Wang, J.‐N., Wei, B., Wen, J., Li, J., Wu, Y.‐G., Meng, X.‐M. hsa‐miR‐500a‐3P alleviates kidney injury by targeting MLKL‐mediated necroptosis in renal epithelial cells. FASEB J. 33, 3523–3535 (2019). http://www.fasebj.org

E-cadherin is a major component of tubular adherent proteins that maintain intercellular contacts and cell polarity in epithelial tissue. It is involved in pathological processes of renal cell carcinoma and fibrotic diseases via epithelial-mesenchymal transition. Although studies have shown E-cadherin is significantly downregulated in acute kidney injury (AKI), its function in AKI is unknown. Here, we evaluated cell damage and inflammation in cisplatin-stimulated tubular epithelial cell lines after disrupting E-cadherin and restoring it with PPBICA, a small molecule identified by high-throughput screening. We also determined the therapeutic potential of restoring E-cadherin in vivo. Results show cisplatin reduced E-cadherin expression both in mouse kidney and proximal tubular epithelial cell lines (mTECs). PPBICA restored E-cadherin levels, which increased cell viability while attenuating programmed cell death. This may be mediated via deactivation of the RIPK1/RIPK3 axis and decreased caspase3 cleavage. In addition, PPBICA suppressed inflammatory response in cisplatin-treated mTECs, which correlated with suppressed NF-κB phosphorylation and promoter activity. In contrast, disruption of E-cadherin promoted cell damage and inflammation. PPBICA failed to further attenuate kidney damage in E-cadherin knockdown cells, indicating that PPBICA protects against mTECs through E-cadherin restoration. We also found that peritoneal injection of PPBICA in mice prevented loss of renal function and tubular damage by suppressing NF-κB-driven renal inflammation and RIPK-regulated programmed cell death. This was driven by restoration of E-cadherin in cisplatin nephropathy. Additionally, PPBICA attenuated cisplatin-induced kidney damage in an established AKI model, indicating its therapeutic potential in the treatment of AKI. In conclusion, E-cadherin plays functional roles in tubule integrity, programmed cell death, and renal inflammation. Our results underscore the potential of E-cadherin restoration as a novel therapeutic strategy for AKI.

BackgroundA unified clinical approach to diagnose autoimmune encephalitis was published in Lancet Neurology in 2016. Purpose of our study is to examine the feasibility and reasonability of the 2016 “A clinical approach to diagnosis of autoimmune encephalitis” in China with a retrospective study.MethodsWe retrospectively collected 95 cases of autoimmune encephalitis and non autoimmune encephalitis cases with detailed clinical data from Beijing Tongren Hospital and the China National Knowledge Infrastructure (CNKI). All cases were analysed stepwise according to the approach in Lancet Neurology to compare the new diagnosis with the final clinical diagnosis.ResultsThe disease course of these 95 cases ranged from 2 to 540 days. Initial symptoms include fever, headache, seizure, mental and behavioral disorders, memory deterioration and illusion. Based on symptoms and signs when the patient came to the hospital, the sensitivity and specificity of criteria were as follows: possible autoimmune encephalitis (pAE) 84% and 94%, definite autoimmune limbic encephalitis (dALE) 38% and 96%, probable anti-N-methyl-D-aspartate receptor encephalitis (prNMDARE) 49% and 98%. The sensitivities of the above three criteria and the specificity of pAE were low during early disease stage, while the specificities of dALE and prNMDAER remained relatively high in different time periods.ConclusionsThis new autoimmune encephalitis diagnostic approach can recognize possible autoimmune encephalitis. The chances of a case being autoimmune-mediated following classification as autoimmune encephalitis with the new criteria are high. The flowchart is recommended to use as a whole. At the early disease stage, criteria with low sensitivity and high specificity, such as dALE and prNMDARE, lead most cases to enter subsequent diagnosis steps, namely autoantibody detection in the flowchart. Final diagnoses can only be made by autoantibody tests. These factors may make it challenging for clinicians to make diagnosis promptly and to begin immune-modulating therapy immediately. Moreover, the criteria for patients with paraneoplastic syndromes (PNSs) should be considered to avoid diagnosis omission. For Chinese patients, a multi-centre, prospective study on the clinical manifestations, laboratory diagnostic technology, therapy, and prognosis is greatly needed.Electronic supplementary materialThe online version of this article (10.1186/s12883-017-0974-3) contains supplementary material, which is available to authorized users.