ORCID ID
0000-0002-2615-2868
Publication Date
2022-03-15
Document Type
Doctoral Dissertation
Academic Program
Cancer Biology
Department
Molecular Cell and Cancer Biology (MCCB)
First Thesis Advisor
Merav Socolovsky
Keywords
Erythropoietin (Epo), Erythropoietin Receptor (EpoR), MCV, Erythroid Terminal Differentiation (ETD), Ribosome Biogenesis
Abstract
Erythroid terminal differentiation couples sequential cell divisions with progressive reductions in cell size. The erythropoietin receptor (EpoR) is essential for erythroblast survival, but its other functions are not well characterized. I used Epor−/− mouse erythroblasts endowed with survival signaling to identify novel non-redundant EpoR functions. I found that, paradoxically, EpoR signaling increases red cell size while also increasing the number and speed of erythroblast cell cycles. Specifically, I found that high levels of EpoR signaling increase the size and shorten the cycle of early erythroblasts, which are amongst the fastest cycling somatic cells. I confirmed the effect of erythropoietin (Epo) on red cell size in human volunteers, whose mean corpuscular volume (MCV) increases following Epo administration. Our work shows that EpoR signaling alters the expected inverse relationship between cell cycle length and cell size. Further, diagnostic interpretations of increased MCV should now include high Epo levels and hypoxic stress.
The ability of EpoR signaling to increase cell size in rapidly cycling early erythroblasts suggests that these cells have exceptionally efficient EpoR-driven mechanisms for growth. I found evidence for this in ongoing work, where Epor−/− and Stat5−/− single-cell transcriptomes show dysregulated expression of ribosomal proteins and rRNA transcription and processing genes. Global rates of ribosomal rRNA transcription and protein synthesis increase in an EpoR dependent manner during a narrow developmental window in early ETD, coincident with the time of cell cycle shortening. Our work therefore suggests EpoR-driven regulation of ribosome biogenesis and translation orchestrating rapid cycling and cell growth during early ETD.
Repository Citation
Hidalgo D. (2022). Novel Functions of Erythropoietin Receptor Signaling. Morningside Graduate School of Biomedical Sciences Dissertations and Theses. https://doi.org/10.13028/97wz-0493. Retrieved from https://escholarship.umassmed.edu/gsbs_diss/1176
DOI
10.13028/97wz-0493
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