Bridging the gap of late gestation human nephrogenesis using a non-human primate model

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Project Summary Premature infants have low nephron number (endowment) and are at high risk for chronic kidney disease (CKD) and end stage renal disease as adults. Most nephrons are added late in gestation through a poorly understood process called lateral branch nephrogenesis (LBN). As direct study of late gestation human kidney development is difficult, the non-human primate model (rhesus macaque) was recently identified as a suitable model to bridge this knowledge gap. The long-term goal is to apply the molecular findings of LBN in the non-human primate model towards development of therapeutic methods aimed at extending nephrogenesis in preterm infants. The central hypothesis is that a shift in the signaling milieu involving components of the developing kidney (nephron progenitor cells (NPC), ureteric bud (UB), and stroma) results in sustaining LBN over multiple weeks in late gestation. The rationale for this proposed research is that the genetically tractable non-human primate model system can be used to test hypotheses and apply therapeutic interventions aimed at improving human nephron endowment. The central hypothesis will be tested by using the latest molecular technologies to understand the molecular mechanism sustaining LBN in the non-human primate, including single-cell RNA sequencing, laser capture microdissection with RNA sequencing, single-nucleus RNA sequencing, and single-nucleus ATAC sequencing. Preliminary morphologic study on the postnatal day two marmoset kidney identified a single ureteric stalk with lateral branches consistent with LBN, suggesting the common marmoset could be used as a genetically tractable primate model. Expected outcomes include assembly of the largest primate late gestation developing kidney molecular dataset and identification of genes and pathways enriched and regulatory networks active during LBN, as well as identification of a genetically tractable model to study LBN to understand why prematurity leads to early cessation of nephrogenesis in humans, and how to extend it. These results are expected to have a positive impact on the current understanding of late gestation human nephrogenesis by identifying molecular pathways and potential therapeutic interventions for those born prematurely. In addition to the aims outlined in this proposal, career development plans include didactic training in molecular biology and bioinformatics through the Certificate program in Bioinformatics, wet-lab experience with the latest molecular technologies and multi- omic platforms, and career advancement through a selected advisory committee for transition to independence and submission of R01 during the K08 award period.