Abstract 39: Fate Of Renin Cell Progenitors In The Developing Kidney Vasculature

Abstract

The unique spatial arregement of the kidney arterioles is an essential event for its development. However, the mechanisms that govern this process are still poorly understood. During nephrogenesis, a group of stromal cells expressing the Forkhead Box D1 ( FoxD1 ) transcription factor (TF) will give rise to the metanephric progenitors for the mural cells of the kidneys arteries and arterioles. We aim to identify the core TFs involved in the cell fate along the differentiaton pathways of the developing kidney vasculature. Therefore, we generated Foxd1-cre; mTmG mice, whose Foxd1 derivative cells are labeled with green fluorescent protein (GFP). GFP+ cells were isolated from 5 (P5) or 30 (P30) days old mice kidneys, and processed either for single-cell RNA-Seq (scRNA-Seq) or for single-cell Assay for Transposase-Accessible Chromatin (scATAC-Seq ). The top5 highly expressed TFs on scRNA-Seq at P5 are: Tcf21, Zeb2, Meis2, Cebpd and Nme3 (p_adjusted_value(padj)= 0, 3.8E-187, 3.9E-180, 4E-172, 4.1E-172 and 3.2E-154, respectively). They are involved in developmental processes and cell proliferation. At P30, the top5 highly expressed TFs are: Atf3, klf2, Fos, Nr4a2 and Junb (padj= 4.2E-294, 2.1E-200, 3.5E-182, 1.7E-52 and 0.2E-24, respectively). They are implicated with calcium-signaling pathway and inflammation. Additionally, scATAC-Seq identifies regions of accessible chromatin for pontential TFs binding, leading to changes in gene expression content and cell identity. At P30, scATAC-Seq showed differential accessible regions with subsequent putative motif enrichment analysis for the TF N4a2 (padj: 4E-297). This is in accordance with our scRNA-Seq results and might play a role in the Foxd1 progenitors cell fate decisions. Our results tracks the fate of the Foxd1+ cells during the kidney vasculature assembly and suggest a new transcription factors network that might play a role to orchestrate cell fate decisions during kidney vascular development.