Abstract: FR-PO992
Aging Alters Microenvironmental Cues for Gli1+ Myofibroblast Progenitors to Promote Tissue Remodeling in the Kidneys
Session Information
- CKD Mechanisms: From Mendel to Mars
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
- Muto, Yoshiharu, Washington University in St Louis, St Louis, Missouri, United States
- Ó hAinmhire, Eoghainín, Washington University in St Louis, St Louis, Missouri, United States
- Machado, Flavia G., Washington University in St Louis, St Louis, Missouri, United States
- Humphreys, Benjamin D., Washington University in St Louis, St Louis, Missouri, United States
Background
Aging is associated with decreased renal function as well as tissue alteration including interstitial fibrosis. We previously identified Gli1+ myofibroblast progenitors that contribute to tissue fibrosis in the kidney and other organs. However, the role of this cell type in aging-induced alteration in the kidney remains elucidated.
Methods
We genetically labeled Gli1+ cells in Gli1-CreERt2; R26-tdTomato mice by pulsing with tamoxifen at 8 weeks of age and chasing them until 12 weeks (young) or 2 years of age (old). We sorted tdTomato+ cells and performed bulk RNA-seq. We also performed single nucleus transcriptomic analysis (snRNA-seq) on these mouse kidneys (n=3 pairs: 12 weeks vs 2 years of age) using 10x Genomics platform.
Results
We identified tdTomato+ cells in 2-year-old mouse kidneys labeled at 8 weeks of age. Bulk RNA-seq on sorted tdTomato+ cells from aged kidneys showed a tissue-remodeling gene expression signature with increased Ccn2, Serpina1b, Mmp3 expressions. We performed snRNA-seq on these mouse kidneys and identified all major cell types (35,592 nuclei from n=3 young and old kidneys; 19 cell types). We observed a large cluster of immune cells as well as emergence of Vcam1+ failed-repair proximal tubular cells (FR-PTC) with pro-inflammatory and pro-fibrotic gene expression signature in aged kidneys. Immunofluorescence analysis validated Vcam1+ atrophic tubules in 2-year-old mouse kidneys. Intercellular communication inference based on snRNA-seq data indicated interactions between FR-PTC and fibroblast/pericyte cluster through molecules modifying tissue fibrosis (Tgfb2, Spp, Pdgfd, Bmp6). Endothelin expressed in FR-PTC was also predicted to target fibroblast/pericytes in 2-year-old mice. In situ hybridization validated high level of Edn1 expression in Vcam1+ tubular cells, suggesting a potential role of endothelin to mediate interaction between FR-PTC and Gli1+ myofibroblast progenitors to promote interstitial fibrosis in elderly population.
Conclusion
By combining long-term lineage tracing and snRNA-seq we elucidated a molecular interaction between Gli1+ myofibroblast progenitor and FR-PTC. Targeting this interaction may mitigate age-related renal fibrosis.
Funding
- NIDDK Support