PUM2 Lowers HDAC9 mRNA Stability to Improve Contrast-Induced Acute Kidney Injury by Attenuating Oxidative Stress and Promoting Autophagy.

backgruoundContrast-induced acute kidney injury (CIAKI) is the third leading cause of hospital-acquired acute kidney injury and diabetes mellitus (DM) has been identified as a risk factor for CIAKI. However, the molecular mechanism underlying DM-CIAKI remains unclear and requires further investigation.

methodsMouse and cell models of DM-CIAKI were established. Kidney function was evaluated by measuring biochemical indicators and using hematoxylin and eosin staining. Gene and protein abundance was assessed using real-time quantitative reverse transcription polymerase chain reaction, immunohistochemistry, immunofluorescence, and Western blotting. Glutathione peroxidase, superoxide dismutase, and malondialdehyde were measured using commercial kits, and reactive oxygen species were detected using a dihydroethidium (DHE) probe and the 2',7'-dichlorofluorescein diacetate (DCFH-DA) method. Apoptosis in tissues and cells was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Cell viability and proliferation were measured using Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine (EdU) assays. The interaction between pumilio RNA binding family member 2 (PUM2) and histone deacetylase 9 (HDAC9) was validated using RNA immunoprecipitation (RIP) and RNA pull-down assays.

resultsPUM2 expression was markedly reduced in DM-CIAKI models, whereas HDAC9 expression was notably increased. Subsequently, PUM2 silencing aggravated kidney injury in DM-CIAKI mice by enhancing oxidative stress and suppressing autophagy, whereas HDAC9 inhibition or HDAC9 silencing had the opposite effects. Mechanistically, PUM2 could suppressed the stability of HDAC9 mRNA, thereby attenuating HDAC9 expression. Furthermore, HDAC9 overexpression abolished PUM2 overexpression-mediated inhibition of oxidative stress and promotion of autophagy in high glucose- and contrast media-treated human kidney-2 (HK-2) cells.

conclusionPUM2 overexpression suppressed oxidative stress and promoted autophagy to alleviate renal injury in DM-CIAKI by interacting with HDAC9 mRNA, which mediated HDAC9 and mRNA degradation and inhibited HDAC9 expression.