title: Inhibition of autophagy increases apoptosis during re-warming after cold storage in renal tubular epithelial cells.
abstract: Prolonged cold storage and re-warming (CS/REW) of kidneys are risk factors for delayed graft function (DGF). Studies in renal tubular epithelial cells (RTECs) have determined apoptosis and autophagy in models of either cold storage (CS) or re-warming alone. The effect of both cold storage and re-warming on apoptosis and autophagy, in RTECS is not known and is relevant to DGF as the kidney is subjected to both CS and re-warming. We hypothesized that CS/REW of RTECs would induce autophagy that protects against apoptosis. In CS/REW, there was increased autophagic flux of RTECs. Autophagy inhibition using an Atg5 siRNA resulted in increased cleaved caspase-3 and increased apoptotic cells (on both morphology and annexin V staining) during CS/REW. The effect of autophagy inhibition on necrosis in RTECs is unknown. There were increased necrosis and caspase-1, a mediator of necrosis, during CS/REW, and the Atg5 siRNA had no effect on necrosis and caspase-1. In a kidney transplant model, there was an increase in LC3 II, a marker of autophagy, in kidneys transplanted after cold storage. In summary, autophagic flux is increased during CS/REW. Autophagy inhibition resulted in increased cleaved caspase-3 and increased apoptosis during CS/REW without an effect on necrosis or caspase-1. In conclusion, autophagy inhibition in RTECs after CS/REW induces apoptotic cell death and may be deleterious as a therapy to decrease DGF.
authors.affiliation: University of Colorado, Denver, CO, USA.
authors.forename: Swati
authors.initials: S
authors.lastname: Jain
authors.forename: Daniel
authors.initials: D
authors.lastname: Keys
authors.forename: Trevor
authors.initials: T
authors.lastname: Nydam
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Plenter
authors.forename: Charles L
authors.initials: CL
authors.lastname: Edelstein
authors.forename: Alkesh
authors.initials: A
authors.lastname: Jani
mesh_terms: D000818:Animals; D017209:Apoptosis; D001343:Autophagy / Q000502:physiology*; D020170:Caspase 1 / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D051799:Delayed Graft Function / Q000209:etiology; D004847:Epithelial Cells / Q000502:physiology; D016030:Kidney Transplantation; D007684:Kidney Tubules / Q000473:pathology*; D018942:Macrolides / Q000494:pharmacology; D009926:Organ Preservation; D017694:Rewarming; D013552:Swine
chemical_list: D018942:Macrolides; C040929:bafilomycin A1; D053148:Caspase 3; D020170:Caspase 1
keywords: apoptosis; autophagy; cold storage; re-warming