PUM2 Lowers HDAC9 mRNA Stability to Improve Contrast-Induced Acute Kidney Injury by Attenuating Oxidative Stress and
Wei Chen1,2, Hengcheng Lu1,2,3, Wenni Dai1
1Department of Nephrology, The Second Xiangya Hospital, Central South University, Key Lab of Kidney Disease and Blood Purification in Hunan, Changsha, China.
Insights
Diabetes mellitus exacerbates contrast-induced acute kidney injury (CIAKI). PUM2 overexpression protects kidneys by reducing oxidative stress and enhancing autophagy via HDAC9 mRNA degradation, offering a potential therapeutic target for DM-CIAKI.
Area of Science:
- Nephrology
- Molecular Biology
- Biochemistry
Background:
- Contrast-induced acute kidney injury (CIAKI) is a significant cause of hospital-acquired kidney damage.
- Diabetes mellitus (DM) is a known risk factor for CIAKI, but its underlying molecular mechanisms require further elucidation.
Purpose of the Study:
- To investigate the molecular mechanisms of DM-associated CIAKI.
- To explore the role of Pumilio RNA binding family member 2 (PUM2) and Histone Deacetylase 9 (HDAC9) in DM-CIAKI.
Main Methods:
- Established mouse and cell models of DM-CIAKI.
- Assessed kidney function, oxidative stress markers, apoptosis, and cell viability.
- Quantified gene and protein expression using RT-qPCR, Western blot, and immunohistochemistry.
- Validated PUM2 and HDAC9 interaction using RNA immunoprecipitation and pull-down assays.
Main Results:
- PUM2 expression was decreased, while HDAC9 expression was increased in DM-CIAKI models.
- PUM2 silencing worsened kidney injury by increasing oxidative stress and decreasing autophagy.
- HDAC9 inhibition or silencing ameliorated kidney injury.
- PUM2 suppressed HDAC9 mRNA stability, thereby reducing HDAC9 expression.
Conclusions:
- PUM2 overexpression alleviates renal injury in DM-CIAKI by suppressing oxidative stress and promoting autophagy.
- This protective effect is mediated through PUM2's interaction with HDAC9 mRNA, leading to HDAC9 degradation and reduced expression.
Backgruound:
Contrast-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.
Methods:
Mouse 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.
Results:
PUM2 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.
Conclusion:
PUM2 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.
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