title: Autophagy protects the proximal tubule from degeneration and acute ischemic injury.
abstract: Autophagy is a bulk protein degradation system that likely plays an important role in normal proximal tubule function and recovery from acute ischemic kidney injury. Using conditional Atg5 gene deletion to eliminate autophagy in the proximal tubule, we determined whether autophagy prevents accumulation of damaged proteins and organelles with aging and ischemic renal injury. Autophagy-deficient cells accumulated deformed mitochondria and cytoplasmic inclusions, leading to cellular hypertrophy and eventual degeneration not observed in wildtype controls. In autophagy-deficient mice, I/R injury increased proximal tubule cell apoptosis with accumulation of p62 and ubiquitin positive cytoplasmic inclusions. Compared with control animals, autophagy-deficient mice exhibited significantly greater elevations in serum urea nitrogen and creatinine. These data suggest that autophagy maintains proximal tubule cell homeostasis and protects against ischemic injury. Enhancing autophagy may provide a novel therapeutic approach to minimize acute kidney injury and slow CKD progression.
authors.affiliation: Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kimura
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Takabatake
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Jun-ya
authors.initials: JY
authors.lastname: Kaimori
authors.forename: Isao
authors.initials: I
authors.lastname: Matsui
authors.forename: Tomoko
authors.initials: T
authors.lastname: Namba
authors.forename: Harumi
authors.initials: H
authors.lastname: Kitamura
authors.forename: Fumio
authors.initials: F
authors.lastname: Niimura
authors.forename: Taiji
authors.initials: T
authors.lastname: Matsusaka
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Soga
authors.forename: Hiromi
authors.initials: H
authors.lastname: Rakugi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Isaka
mesh_terms: D058186:Acute Kidney Injury / Q000517:prevention & control*; D000818:Animals; D001343:Autophagy; D000071187:Autophagy-Related Protein 5; D006984:Hypertrophy; D007668:Kidney / Q000098:blood supply* / Q000473:pathology; D007687:Kidney Tubules, Proximal / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008869:Microtubule-Associated Proteins / Q000502:physiology; D015427:Reperfusion Injury / Q000517:prevention & control*
chemical_list: C495773:Atg5 protein, mouse; D000071187:Autophagy-Related Protein 5; D008869:Microtubule-Associated Proteins