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Abstract: FR-PO995

DZNep, a Histone Modification Inhibitor, Inhibits HIF1α Binding to TIMP2 Gene by Reducing Open Chromatin Area

Session Information

  • CKD: Pathobiology - I
    November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

  • 2203 CKD (Non-Dialysis): Mechanisms

Authors

  • Yamazaki, Tomotaka, Tokyo Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Bunkyo-ku, Tokyo, Japan
  • Mimura, Imari, Tokyo Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Bunkyo-ku, Tokyo, Japan
  • Nangaku, Masaomi, Tokyo Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Bunkyo-ku, Tokyo, Japan

Group or Team Name

  • Division of Nephrology and Endocrinology
Background

Even after complete resolution of acute kidney injury (AKI), some patients develop chronic kidney disease (CKD) and end-stage renal failure. The mechanism of AKI to CKD is thought to be that transient AKI damage may cause the epigenetic changes, such as histone modification and DNA methylation, that lead to CKD progression. Our previous report showed that 3-Deazaneplanocin A (Dznep), a histone modification inhibitor, suppressed renal fibrosis and the expression of Tissue Inhibitor of Metalloproteinase 2 (TIMP2), which is thought to be a profibrotic factor, in ischemia-reperfusion mice. In this study, we investigated the epigenetic regulation of TIMP2 in tubular cells.

Methods

Human kidney-2 (HK-2) cells were treated with Dznep and examined for histone methylation and open chromatin status by Western-blotting, Chip-qPCR and Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE)-qPCR. The relationship with hypoxia-inducible factor 1α (HIF1α) was also examined by Chip-qPCR and reporter assay.

Results

In HK-2 cells, TIMP2 expression was upregulated under hypoxia and suppressed by Dznep. Dznep treatment had a repressive effect on various histone methylation such as H3K4me3, H3K27me3 and H3K9me3. The Chip-qPCR of H3K4me3 for TIMP2 gene region showed that Dznep treatment reduced H3K4me3. The FAIRE-qPCR of TIMP2 gene region showed that Dznep treatment suppressed the percentage of open chromatin area, which was elevated by hypoxia. In addition, the Chip-qPCR of HIF1α for TIMP2 gene showed that Dznep inhibited the binding region of HIF1α, which was elevated by hypoxia. The reporter assays for the binding region of HIF1α showed enhanced transcriptional activity by hypoxia.

Conclusion

Dznep suppresses the expression of TIMP2, which is elevated by hypoxia, by altering the histone methylation state of TIMP2 gene, decreasing the percentage of open chromatin, and inhibiting HIF1α binding.

The epigenetic regulation of TIMP2 by TIMP2.

Funding

  • Government Support – Non-U.S.