title: Neutrophil gelatinase-associated lipocalin worsens ischemia/reperfusion damage of kidney cells by autophagy.
abstract: This study aimed to explore the influence of neutrophil gelatinase-associated lipocalin on autophagy and its role in ischemia/reperfusion injury in human kidney-2 (HK-2) cells during acute kidney injury (AKI). HK-2 cells were given hypoxia/reoxygenation treatment for different times to simulate ischemia/reperfusion injury. Autophagy was evaluated by western blot and immunofluorescence of GFP-LC3. Cell viability was tested to reflect the degree of cell damage. The autophagy inhibitor 3-MA was used to inhibit autophagy and determine the role of autophagy in ischemia/reperfusion injury. HK-2 cells were hypoxia for 1 h, followed by reoxygenation treatment for 24 h. These cells were then exposed to human recombinant protein neutrophil gelatinase-associated lipocalin (NGAL) (50, 100, 200, 400, or 1000 ng/mL) with or without 3-MA. Our results showed that autophagy was induced by hypoxia treatment and was further enhanced by reoxygenation after hypoxia treatment. Cell viability was decreased with the inhibition of autophagy in the process. Autophagic flux was further induced with NGAL (>200 ng/mL), while cell viability declined in this condition. Cell viability was recovered when autophagy was inhibited. These results indicate that autophagy plays, in part, a protective role in renal ischemia/reperfusion injury. Furthermore, the data suggest that NGAL strengthens the level of autophagy in this process. Overall, a large quantity of NGAL produced by renal proximal tubular epithelial cells may induce excessive autophagy and increase renal ischemia/reperfusion injury in acute kidney injury.
authors.affiliation: a Department of Clinical Laboratory , Peking University Third Hospital , Hai Dian District , Beijing , PR China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhang
authors.affiliation: a Department of Clinical Laboratory , Peking University Third Hospital , Hai Dian District , Beijing , PR China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Yang
authors.affiliation: a Department of Clinical Laboratory , Peking University Third Hospital , Hai Dian District , Beijing , PR China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Cui
authors.affiliation: a Department of Clinical Laboratory , Peking University Third Hospital , Hai Dian District , Beijing , PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
mesh_terms: D058186:Acute Kidney Injury / Q000473:pathology; D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives; D001343:Autophagy / Q000187:drug effects*; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival; D002738:Chloroquine / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007684:Kidney Tubules / Q000098:blood supply* / Q000473:pathology*; D000071068:Lipocalin-2 / Q000494:pharmacology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D015427:Reperfusion Injury / Q000473:pathology*
chemical_list: C489506:LCN2 protein, human; D000071068:Lipocalin-2; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D011994:Recombinant Proteins; C025946:3-methyladenine; D002738:Chloroquine; D000225:Adenine
keywords: Acute kidney injury; autophagy; ischemia/reperfusion injury; neutrophil gelatinase-associated lipocalin; renal tubular epithelial cell