The Novel Erythropoietin (EPO)-Regulated Adaptor Protein, “C1ORF186/RHEX”, Modulates the EPO-Dependent Proliferation of Human Erythroid Progenitor Cells

Author

Arianna True, University of New Hampshire - Main CampusFollow

Date of Award

Spring 2022

Project Type

Senior Honors Thesis

College or School

COLSA

Department

Department of Molecular, Cellular, and Biomedical Sciences

Program or Major

Biomedical Science: Medical and Veterinary Sciences

Degree Name

Bachelor of Science

First Advisor

Don Wojchowski

Abstract

Erythropoietin (EPO) is a glycoprotein hormone and hematopoietic growth factor that is essential for the formation of erythroid progenitor cells (EPCs) and drives the production of 10⁶ red blood cells per second. Produced in select renal fibroblastic cells in response to hypoxia, anemia, or chemotherapy, EPO targets EPCs in bone marrow and binds to rare cell surface receptors (EPOR’s) that couple to the Janus PTK, JAK2. EPO’s signals include pro-survival, growth, and developmental responses, certain of which are not mechanistically understood. Clinically, recombinant EPO is an important therapeutic for chronic renal disease, anemia due to chemotherapy and myelodysplastic syndrome. Our laboratory has discovered an ORF, “C1ORF186 / “RHEX”, that is rapidly tyrosine phosphorylated approximately 100-fold in response to EPO, and unexpectedly is an integral plasma membrane predicted novel adaptor protein.¹ My studies with the Wojchowski laboratory used a lentivirus approach to test effects of reinforcing RHEX expression, using human UT7epo cells as a unique EPO- dependent EPC cell line model. This involved i) lentivirus vector design, restriction site analysis, and lentivirus production; ii) transduction of UT7epo cells towards ectopic expression of RHEX, followed by MACS isolation of CD4t-tagged cells; and assays of effects of enforced RHEX expression (GOF) on UT7epo cell growth. This altering of RHEX levels substantially affected EPO dependent UT7epo cell by decreasing proliferation, while EPO-dependent survival was not significantly altered. Initial new insight therefore is gained into RHEX’s specific effects, and potential action mechanisms.

Recommended Citation

True, Arianna, "The Novel Erythropoietin (EPO)-Regulated Adaptor Protein, “C1ORF186/RHEX”, Modulates the EPO-Dependent Proliferation of Human Erythroid Progenitor Cells" (2022). Honors Theses and Capstones. 649.
https://scholars.unh.edu/honors/649