Molecular determinants of nephron vascular specialization in the kidney

The kidney vasculature is specialized to filter waste products from the blood, regulate blood pressure, and balance electrolytes. Although recent advances in stem cell studies have enabled the partial generation of kidney tissues in vitro, recapitulating the complex vascular structures of the kidney remains a daunting task. The molecular pathways that specify and sustain kidney vascular heterogeneity to perform these diverse tasks are not well characterized. Here, we have employed high throughput bulk and single-cell RNA sequencing of the non-lymphatic vasculature of the kidney to uncover the progression of pathways that dictate the developmental transition of nephrogenesis and vascular zonation from embryos to adulthood. We show that glomeruli and its associated vessels, manifest vascular-specific signatures expressing defined transcription factors, ion channels, solute transporters, and paracrine factors choreographing kidney functions. Notably, the ontology of the glomerulus coincides with induction of several unique transcription factors, including Tbx3, Gata5, Prdm1, and Pbx1. Selective deletion of Tbx3 in endothelial cells result in glomerular hypoplasia, microaneurysms and regressed fenestrations leading to fibrosis. Unraveling the molecular determinants of kidney vascular signatures will lay the foundation for rebuilding nephrons and understanding the pathogenesis of kidney diseases. Expression profiling by high throughput sequencing data of transgenic Tbx3 mutant mice, transduced HUVEC cell lines, and human kidney ECs; GPL21103 Illumina HiSeq 4000 (Mus musculus); GPL20301 Illumina HiSeq 4000 (Homo sapiens).