Abstract: FR-PO1085
Chromatin Remodeling Factor, INO80, Inhibits PMAIP1 in Renal Tubular Cells Through Exchange of Histone Variant H2A.Z for H2A
Session Information
- CKD Mechanisms: Progression, Fibrosis, and Beyond
November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2303 CKD (Non-Dialysis): Mechanisms
Authors
- Mimura, Imari, Tokyo Daigaku, Bunkyo-ku, Tokyo, Japan
- Miura, Rika, Tokyo Daigaku, Bunkyo-ku, Tokyo, Japan
- Nangaku, Masaomi, Tokyo Daigaku, Bunkyo-ku, Tokyo, Japan
Background
Epigenetic modifications such as histone modifications and chromatin structures in the kidney contribute towards the progression of chronic kidney disease (CKD). In this study, the role of chromatin remodeling factor, inositol requiring 80 (INO80) was investigated because INO80 has been reported to be associated with renal function in a genome-wide analysis. Although INO80 regulates transcription by altering the chromatin structure at the nucleosome level, its role in the kidney remains unknown. Our aim of this study is to clarify the pathophysiological role of INO80 in the kidney.
Methods
We evaluated the expression level of INO80 using UUO (unilateral urethral obstruction) model rats. We also investigated INO80 mRNA expression in a proximal tubular cell line (HK2) under hypoxia. To identify the downstream target genes of INO80, we performed RNA-seq using siRNA of INO80. We examined the effects of INO80 on apoptosis of tubular cells.
Results
The mRNA level of INO80 extracted from UUO group (n = 6) was significantly reduced compared to the contralateral kidney group. INO80 knockdown promoted apoptosis, suggesting that INO80 plays a role in inhibiting tubular cell apoptosis. The expression levels of INO80 in HK2 cells under 1% hypoxic condition significantly decreased than those under normoxia. We identified 32 down-regulated genes and three up-regulated genes. These genes were suspected to be INO80 downstream target candidates. As a result of gene ontology (GO) apoptosis-related genes such as TP53 (tumor protein p53), E2F1 (E2F transcription factor 1), and PMAIP1 (phobol-12-myristate-13-acetate-induced protein 1 were significantly associated with INO80 functions. PMAIP1 is a member of pro-apoptotic subfamily of the BCL-2 protein family and is a known target of p53. Chromatin immunoprecipitation was performed on HK-2 cells with INO80 knockdown using the H2A.Z. antibody, because INO80 has been reported to remove the H2A.Z. variant and exchange it for the H2A variant. INO80 knockdown significantly increased H2A.Z. in the promoter region of PMAIP1, while H2A expression significantly decreased in the promoter region of PMAIP1.
Conclusion
INO80 plays an important role in exchanging H2A.Z. for H2A in the promoter region of PMAIP1 in tubular cells to inhibit apoptosis during CKD progression.
Funding
- Private Foundation Support