Abstract: FR-OR14
Integrated Multi-Omics Reveal the Complexity of TGF-β Signalling to Chromatin in Induced Pluripotent Stem Cell-Derived Kidney Organoids
Session Information
- Diabetic Kidney Disease: Back to the Basics
November 05, 2021 | Location: Simulive, Virtual Only
Abstract Time: 04:30 PM - 06:00 PM
Category: Diabetic Kidney Disease
- 601 Diabetic Kidney Disease: Basic
Authors
- Davis, Jessica L., University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Kennedy, Ciarán, University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Clerkin, Shane, University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Treacy, Niall, University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Murphy, Alison A., University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Moss, Catherine, University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Andrews, Darrell C., University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Dodd, Thomas K., University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
- Crean, John, University College Dublin Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland
Group or Team Name
- Crean lab
Background
Critical pathological features of diabetic kidney disease are now accepted to include dysregulation of epigenetic processes as evidenced by the observed differential methylation in patients with or without progressive disease. TGFβ resides at the centre of therapeutic approaches for the treatment of renal fibrosis, but few intervention studies have demonstrated clinical efficacy. Recently, we demonstrated a novel direct interaction between Smad3 and EZH2, the enzymatic component of the polycomb repressive complex 2 (PRC2) during cell fate specification.
Methods
Using the 10X Genomics platform, we performed single cell RNA-seq and -ATAC-seq on human iPSC-derived kidney organoids treated with the EZH2 inhibitor, GSK343, for 1 hour prior to treatment with TGFβ1 for 48 hours.
Results
Single cell RNA-seq analysis revealed that TGFβ1 treated organoids exhibited a similar fibrotic response to what is observed in human diabetic kidneys. Furthermore, TGFβ1 induced the differentiation of resident stromal cells into activated myofibroblasts, and this was accompanied by the upregulation of fibrotic genes such as α-smooth muscle actin and transgelin, consistent to what is observed in vivo. Single cell ATAC-seq of iPSC-derived kidney organoids treated with TGFβ1 revealed that TGFβ increases chromatin accessibility at all promoters, DNase I hypersensitive, and transcription start sites in all cell types present within the organoid. Furthermore, TGFβ1 increased chromatin accessibility at some enhancers and this was cell-type dependent. We have shown that pre-treatment with EZH2 inhibitor, GSK343, prevents TGFβ mediated increase in chromatin accessibility and inhibits the expression of the fibrotic marker, α-smooth muscle actin.
Conclusion
We propose that that the enzymatic function of the polycomb repressive complex is necessary for TGFβ1 induced increase in chromatin accessibility and its subsequent gene regulatory functions. Understanding the exact nature of how TGFβ cooperates with epigenetic complexes at the chromatin level will allow for a more comprehensive understanding of how changes in cell fate occur in developmental and pathological contexts. Manipulation of the association between Smad3 and EZH2 may be a useful therapeutic strategy for the resolution of renal fibrosis.