Transcriptional Landscape of Cells of Renin Lineage Following Podocyte Depletion

Renin producing cells of the juxtaglomerulus, herein called cells of renin lineage (CoRL), have garnered recent interest for their propensity to act as a progenitor sink for various kidney cell types including podocytes. Despite recent advances, the process of transdifferentiation of CoRL to podocytes is poorly understood. In this study, we employed a transgenic mouse line which permanently labels CoRL with ZsGreen fluorescent protein, allowing for isolation by fluorescence-activated cell sorting. At 5 days following induction of abrupt podocyte ablation via anti-podocyte sheep IgG, mice were sacrificed and CoRL were isolated by FACS. RNA was subsequently analyzed by microarray. Gene set enrichment analysis (GSEA) was performed and revealed that CoRL display a distinct phenotype following podocyte ablation, primarily consisting of downregulation of metabolic processes and upregulation of immuno-modulatory processes. Additionally, RNA-biology and cell cycle-related processes were also upregulated. Changes in gene expression or activity of a core set of transcription factors including HNF1 and E2F were identified through changes in enrichment of their respective target genes. However, integration of results from transcription factor and canonical pathway analysis indicated that ERR1 and PU-box family members may be the major contributors to the post-podocyte ablation phenotype of CoRL. Finally, top ranking genes were selected from the microarray-based analysis and confirmed by qPCR. Collectively, our results provide valuable insights into the transcriptional regulation of CoRL following abrupt podocyte ablation. Total RNA from FACS ZsGreen CoRL was isolated from uninjured (baseline) mice (n = 4) and mice with experimentally induced focal segmental glomerulosclerosis (FSGS) (podocyte depleted, n = 4) and hybidized to MouseRef-8 (v2.0) Expression BeadChips.