Abstract: SA-PO096
The mRNA Editing via Apobec-1 Is Necessary to Repair Kidneys from Cisplatin (CP)-Induced Renal Injury
Session Information
- AKI: Mechanisms - Primary Injury and Repair - II
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Guo, Xiaojia, Yale University, West Haven, Connecticut, United States
- Velazquez, Heino, Yale and VAMC, West Haven, Connecticut, United States
- Chen, Tian-Min, Yale University, West Haven, Connecticut, United States
- Cheng, Zhongshan, Yale University, West Haven, Connecticut, United States
- Moeckel, Gilbert W., Yale University School of Medicine, New Haven, Connecticut, United States
- Blanc, Valerie, Washington University School of Medicine, ST Louis, Missouri, United States
- Davidson, Nicholas, Washington University School of Medicine, ST Louis, Missouri, United States
- Safirstein, Robert L., Yale and VAMC, West Haven, Connecticut, United States
- Desir, Gary V., Yale and VAMC, West Haven, Connecticut, United States
Background
Cisplatin (CP) induces AKI as the proximal tubules (PT) undergo regulated necrosis. Repair is almost complete following such a single dose. Repeated doses of CP, however, leads to unresolved injury and progresses to chronic kidney disease (CKD). Interrogation of the renal transcriptome throughout the process of AKI to CKD progression identified Apobec1 protein, a cytosine deaminase that binds to and edits mRNAs that regulate mitochondrial metabolism, cell fate and proliferation pathways, which in liver, small intestine and brain play a crucial role in recovery from stress. We therefore examined the role of apobec1 in kidney nephrotoxicity.
Methods
Apobec1 knockout (ko) mice were given CP 15 mg/kg i.p. and renal function, histology, mRNA and protein expression were analyzed and compared to wild type (WT) mice of similar genetic background. We also overexpressed Apobec-1 in PT cells, after CP treatment, and assessed cell viability histologically and by WST-1 assay.
Results
Apobec-1 gene knockout resulted in more severe AKI, plasma creatinine 2.069 mg/dL ± 0.591, n=13) versus 0.228 mg/dL ± 0.087, n=8) 3d (p < 0.01) in WT. Remarkably all apobec1 ko mice died after 6 days, while WT animals all survived. The kidney showed greater necrosis and neutrophil invasion, but no change was noted in TUNEL or ki67 staining. mRNA and protein levels of RIPK3, MLKL, TLR2, and TLR4 were 3.76-, 3.54-, 6.26-, and 40.07-fold higher, respectively (p,001), in Apobec-1 kos than WT kidneys. Overexpression of Apobec-1 in mouse PT cells protected cells from CP-induced cytotoxicity: the CP-induced cell death was 2.35-fold lower in cells transduced with Apobec-1 than in cells transduced with vector alone (n = 4, p < 0.05). Such overexpression of Apobec-1 increased the activities of kinases associated with survival (ERK, STAT3, and AKT) and inhibited those inducing cell death (TLR4, IRF4, and JNK).
Conclusion
We have identified Apobec1 as a crucial gene regulating the necrotic response to CP-induced nephrotoxicity. The studies show that mRNA editing is a key survival response to CP-induced AKI and that increasing Apobec-1 activity could be an effective strategy to reduce or prevent CP-induced AKI.
Funding
- NIDDK Support