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Abstract: FR-OR045

Distinct States of Chromatin Accessibility and MicroRNA Expression in Nephron Progenitor Cells During Development

Session Information

  • Development and Stem Cells
    November 08, 2019 | Location: 152, Walter E. Washington Convention Center
    Abstract Time: 05:18 PM - 05:30 PM

Category: Development, Stem Cells, and Regenerative Medicine

  • 500 Development, Stem Cells, and Regenerative Medicine

Authors

  • Clugston, Andrew Scott, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Bodnar, Andrew J., UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Ho, Jacqueline, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Kostka, Dennis, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Background

Mammalian nephrons develop from a multipotent and self-renewing population of nephron progenitors (NPs) during kidney development. All nephrons are formed prior to birth in humans, and the number of nephrons formed is largely dependent on the number of nephron progenitors during kidney development. Low nephron endowment predisposes individuals to chronic kidney disease and hypertension. NPs that exist early in nephrogenesis are known to be transcriptionally distinct from those in later nephrogenesis. We hypothesize that changes in chromatin accessibility and microRNA (miRNA) expression contribute to developmental age-related changes in the NP transcriptome.

Methods

NP cells were isolated from mouse kidneys using magnetic-activated cell separation with positive selection of Integrin alpha 8 (Itgα8) at embryonic day 14.5 (E14.5), E16.5 and postnatal day 0. To measure transcriptional activity at regulatory features genome-wide, a proportion of the NP cells were assayed for transposase-accessible chromatin (ATAC-seq). Total RNA from remaining NP cells was sequenced using small-RNA sequencing (smRNA-seq).

Results

A total of 35,172 regions of accessible chromatin were identified based on the irreproducible discovery rate (IDR = 0.1), 1,800 of which underwent a statistically significant change in read depth between age groups (FDR = 0.05). More changes in DNA accessibility are observed between E14.5 and E16.5 than between E16.5 and P0 (1,788 and 12, respectively), and a majority of these early changes (79%) represent a reduction in accessibility over time. Findings corroborate published features including reduced activity at the Lin28b gene promoter during nephrogenesis. 1,243 known miRNAs were detected across all NP samples, of which 170 underwent significant changes in expression between the measured time points (padj. ≤ 0.05). These include most members of the let-7 family, which see increased expression coincident with the reduced expression of Lin28b, a published let-7 repressor.

Conclusion

Chromatin accessibility and miRNA expression appear to be distinct in early versus late nephrogenesis.

Funding

  • NIDDK Support