Abstract: TH-OR18
Glutathione-Specific γ-Glutamylcyclotransferase 1 (CHAC1) Is a Kidney Disease Risk Gene by Controlling Ferroptosis
Session Information
- CKD Mechanisms: Prediction, Propagation, and Prevention
November 02, 2023 | Location: Room 119, Pennsylvania Convention Center
Abstract Time: 05:33 PM - 05:42 PM
Category: CKD (Non-Dialysis)
- 2303 CKD (Non-Dialysis): Mechanisms
Authors
- Prasanna, Kolligundla Lakshmi, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Susztak, Katalin, University of Pennsylvania, Philadelphia, Pennsylvania, United States
Background
Despite GWAS identified over 800 loci associated with kidney function, the specific genes, cell types, and mechanisms influenced by these genetic variants largely remain unexplored. In our research, we leveraged human kidney gene expression and methylation quantitative trait data, as well as human kidney single nuclear gene expression and open chromatin analysis, to prioritize CHAC1 on chromosome 15 as a likely causal gene. CHAC1 is essential for maintaining cellular glutathione levels but the role of CHAC1 remains unknown in kidney disease development.
Methods
Using CRISPR technology, we generated CHAC1 heterozygous mice (CHAC1+/-). To study the role of CHAC1 in kidney disease, we induce kidney disease by streptozotocin or folic acid injections or by feeding adenine diet. To uncover the mechanistic role of CHAC1, we used cultured tubule cells and performed biochemical assays.
Results
CHAC1 heterozygous mice (CHAC1+/-) showed no basal differences in kidney function, birth, and growth defects. On induction of kidney disease using streptozotocin or folic acid injection, the CHAC1+/- mice demonstrated improved kidney function (measured by BUN, creatinine, and cystatin C), diabetic kidney injury, and less fibrosis compared to WT counterparts. On chronic adenine feeding by ad libitum chow, the CHAC1+/- mice showed lower chronic kidney disease. The single nuclear ATAC-seq, RNA in situ hybridization, and immunostaining analyses indicated CHAC1 expression in the Loop of Henle (LOH). Cultured primary tubule cells from CHAC1+/- mice showed lower ferroptosis (an iron-dependent form of cell death), preserved cell viability, reduced lipid peroxidation and reactive oxygen species. Derepressed levels of ferroptosis inhibitor, Glutathione peroxidase 4 (GPX4) and the system xCT, and available glutathione levels in CHAC1+/- primary tubule cells likely mediating the resistance to ferroptosis in the conditions of cysteine methionine deprivation or transforming growth factor beta. The lower ferroptosis in CHAC1+/- mice is likely the mechanism for lower fibrosis and better kidney function in disease states (as CHAC1 degrades glutathione).
Conclusion
Our research identified CHAC1 as a novel kidney disease risk gene with a significant role in modulating ferroptosis and cellular glutathione levels in kidney tubule cells.
Funding
- NIDDK Support