Olivia Wang
Pronouns: she/her
Research Mentor(s): Qing Li
Research Mentor School/College/Department: Medicine Division of Hematology & Oncology / Medicine
Program: UROPF
Session: Session 4 (1:40pm – 2:30pm)
Authors: Erin Kroppe, Sophia Fisher, Olivia Wang
Abstract
Hematopoietic stem cells (HSC) maintain normal production of blood cells and self-renew throughout a lifetime. These properties are the basis for multiple therapies including allogeneic transplant and gene therapies for hematologic disorders. However, widespread donor availability for cord blood transplant and cellular therapies are hampered by limitations in expanding HSCs ex vivo. Historically, HSC expansion has been limited by stem cell exhaustion and differentiation. Recent data, suggest dysregulation of protein homeostasis occurs with HSC ex vivo culture and are associated with a loss of HSC function and self-renewal. Recent studies in our lab found HSCs differentially require endoplasmic reticulum associated degradation (ERAD) to maintain self-renewal. ERAD is a multiprotein complex that degrades misfolded proteins and regulates secreted and cell surface proteins. The loss of ERAD leads to dysregulation of signaling pathways and expression of cell surface proteins which leads to altered niche interactions, aberrant proliferation and a loss of function in HSC. Recent studies within our lab have found that ERAD activity decreases with HSC expansion in vitro. Our hypothesis is that in ex vivo culture, the loss of ERAD is associated with the loss of HSCs, and that restoring ERAD will improve both the function and quantity of HSCs within the culture. We developed a high throughput screen to identify novel regulators of ERAD and have identified two novel inhibitors of ERAD activity and four promoters of ERAD activity in an FDA repurposing library. The four promoters of ERAD activity belong to a class of compounds, HSP90 inhibitors. In our proposed studies, we will confirm that these molecules modulate ERAD activity by measuring steady state degradation of ERAD substrates IRE1a and Rheb by immunoblot in vitro cell lines 293T and K562 treated with our ERAD modulators. We expect that activators will decrease ERAD substrate levels and inhibitors will increase their levels relative to control. In the future, we will then test their ability to maintain HSC in culture, modulate ERAD substrates in HSC, and measure frequency by flow cytometry. We expect that promoting ERAD activity will enrich HSC in ex vivo expansion and modulate protein levels of ERAD substrates.
