Abstract: PO0352
Leucine Metabolism and Ketone Bodies Role in AKI
Session Information
- AKI: Mechanisms of Injury
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Saliba, Afaf, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
- Tumova, Jana, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
- Kim, Jiwan John, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
- Sharma, Kumar, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
Group or Team Name
- Center for Renal Precision Medicine, Lab of Dr. Kumar Sharma
Background
Renal ischemia reperfusion (IR) results in injury caused by dynamic process that includes inflammation and extensive cell death. The increase in oxidative stress appears to play a great role in the inflammatory process causing acute kidney injury (AKI) during IR. Oxidative stress activates p53 and promotes cell death. On the other hand, ketones, were shown to decrease oxidative stress and are renal protective under different pathological conditions including AKI. Acetoacetate, one of the major ketone bodies, is a product of leucine catabolism. The means through which ketone bodies could play a protective role still requires further understanding. Computational studies in our lab have uncovered a link between mouse double minute 2 homolog (MDM2), which is a direct inhibitor of p53, and methylcrotonyl-CoA carboxylase 2 (MCCC2), which encodes a mitochondrial enzyme essential for leucine and isovaleric acid catabolism.
Methods
To explore amino acid metabolism and ketone bodies role in AKI we analyzed gene expressions in kidney cortex of mice that have undergone 35 minutes of renal ischemia followed by 24h of reperfusion. Moreover, to further investigate a connection between MDM2 and MCCC2, we knocked-down MDM2 in human kidney 2 (HK2) cells using small interfering RNA (siRNA) transfection at 2 concentrations (100nM and 200nM). Cells were harvested 48 hours post-transfection for mRNA and protein analysis.
Results
Renal ischemia- reperfusion increased levels of p53 and HIF1-alpha consistently with previous studies. Intriguingly, we also got significant decrease in MCCC2 mRNA (n=6) in IR-mice compared to sham operated mice (n=5). Preliminary data from MDM2 knock-down HK2 cells also show p53 upregulation, increased cell death and MCCC2 downregulation. These results are observed both at the mRNA and protein levels at 200nM MDM2 siRNA.
Conclusion
Though preliminary, our data show a consistent decrease in MCCC2 expression at the mRNA levels under AKI provoked by IR. This novel finding could be a steppingstone towards deciphering important pathways in AKI that involve oxidative stress related cell death and dysregulated amino acid. metabolism.
Funding
- Other NIH Support