David Ntsiful
Pronouns: He/Him/His
Research Mentor(s): Kurt Hankenson
Research Mentor School/College/Department: Orthopaedic Surgery / Medicine
Program: UROPF
Session: Session 3 (11:00am – 11:50am)
Authors: David Ntsiful, Kurt Hankenson, Yadav Wagley
Abstract
Genome-wide association studies (GWAS) and their functional follow-up have now uncovered multiple genetic regulators that play a unique role in osteoblast differentiation of human mesenchymal stem cells (hMSCs). Recently, we have established EPDR1 as a human osteoblast effector gene at the STARD3NL locus. Three proxy SNP of the GWAS sentinel SNP (rs1524068, rs6975644, and rs940347) constitute the osteoblast-lineage-specific EPDR1 enhancer that interacts with the EPDR1 promoter. This research aims to evaluate whether the EPDR1 gene is modulated during Notch signaling pathway-mediated human osteoblast differentiation. Notch signaling is a cell-to-cell signaling mechanism that drives human osteoblast differentiation in vitro and affects bone formation and regeneration in vivo. This project aims to assess whether EPDR1 is a downstream modulator of Notch signaling-mediated osteoblast differentiation in vitro. The research will also evaluate whether EPDR1 gene expression increases during Jagged1-mediated hMSC osteoblast differentiation and whether this upregulation is mediated via the GWAS-identified proxy SNP region in an osteoblast-specific manner. We have confirmed that Cas9 protein co-transfection with a set of guides can create a genomic deletion that spans the proxy SNPs region of the putative EPDR1 enhancer region in primary hMSCs: This was achieved by transfecting hMSCs to observe the consistency of deletions over time. Another set of hMSCs was differentiated in the presence of Jagged1 to evaluate the effect on EPDR1 expression and osteoblast differentiation. Later work will examine the genome-edited cells for osteoblast differentiation and correlate with EPDR1 expression. Additionally, we will use bioinformatic analysis to evaluate the presence of Notch response elements within the EPDR1 enhancer and promoter regions for functional follow-up using chromatin immunoprecipitation assays. This work will establish Notch signaling as an extracellular mediator of EPDR1 expression, which functions through the functionally relevant BMD GWAS proxy SNPs.
