title: Na+/H+ exchanger-1 reduces podocyte injury caused by endoplasmic reticulum stress via autophagy activation.
abstract: Podocyte injury has a critical role in the pathogenesis of proteinuria. Induction of endoplasmic reticulum (ER) stress is thought to lead to podocyte injury; however, no effective strategy for reducing ER stress-induced injury has been identified. We investigated specific mechanisms for reducing podocyte injury caused by ER stress. We found that the induction of ER stress in podocytes was related to cytoskeleton injury and increased proteinuria, which was associated with autophagy activation and downregulation of Na(+)/H(+) exchanger-1 (NHE-1) in the rat model of passive Heymann nephritis. Using mouse podocyte cells (MPCs), we showed that ER stress could lead to podocyte injury accompanied by autophagy activation, and the disturbance of autophagy aggravated cytoskeleton loss under conditions of ER stress. The balance between autophagy activation and ER stress was critical to podocyte survival, in which the efficiency of autophagy could have a pivotal role. Strikingly, the overexpression and small interfering RNA knockdown of NHE-1 results suggested that NHE-1 exerts a protective effect by reducing the loss of synaptopodin in MPCs exposed to ER stress. This protective mechanism involves NHE-1 activation of autophagy via the PI3K/Akt pathway to reduce ER stress injury in podocytes. This mechanism may provide a new pathway to prevent podocyte injury.
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Tang
authors.affiliation: 1] State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China [2] Medical College, NanKai University, Tianjin, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Shaoyuan
authors.initials: S
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Hong
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Guangyan
authors.initials: G
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Ribao
authors.initials: R
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Kidney Diseases (2011DIV00088), Department of Nephrology, Chinese PLA Institute of Nephrology and Key Lab, Chinese PLA General Hospital, Beijing, China.
authors.forename: Xiangmei
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D001343:Autophagy; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000502:physiology; D004195:Disease Models, Animal; D059865:Endoplasmic Reticulum Stress; D015433:Glomerulonephritis, Membranous / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D050199:Podocytes / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*
chemical_list: C452850:Slc9a1 protein, rat; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt