Indiana University-Purdue University Indianapolis (IUPUI) / Hematopoietic stem (HSC) and progenitor (HSPC) cells reside in low oxygen (~1-
4%, low O2) bone marrow niches which provide critical signals for maintenance, selfrenewal,
and differentiation. Exposure of HSC/HSPCs to air (~21%) for less than 10
minutes irreversibly diminishes numbers of phenotypic and functional stem cells, a
phenomenon termed extra physiologic oxygen stress/shock. Yet, most studies harvest
and analyze HSC/HSPCs in air and often in fixed cells, leaving endogenous signaling
mechanisms unidentified.
To better understand the endogenous mechanisms regulating HSCs and HSPCs,
we generated the first low O2 landscape of phenotypic/functional/signaling alterations in
live, low O2 harvested/sorted HSC/HSPCs utilizing novel technology. HSC (LSKCD150+)
and HSC/HSPC (LSK) expression, frequency, and stem cell maintenance retention were
enhanced in low O2 relative to historic data and our air data. Transcriptomics uncovered
low O2 differential pathway regulation of HSC/HSPCs and HSCs with analysis identifying
low O2 enrichment of genes/pathways including Ca2+ ion binding, altered sodium hydrogen
(Na+/H+) activity, viral entry, and transmembrane receptor activity in both HSCs and
HSPCs. In exploring the low O2 landscape, we investigated differential low O2 regulation
of Ca2+ and SARS-CoV-2 related pathways/mechanisms in HSCs and HSPCs.
Differential Ca2+ regulation was observed in our transcriptional/proteomic analysis
corroborated by phenotypic/functional data demonstrating increases in low O2 of cytosolic
and mitochondrial Ca2+ flux, ABC Transporter (ABCG2) and Na+/H+ (NHE1) expression,
discovery of a novel low O2 Ca2+ high HSPC population that enhances HSC maintenance
compared to Ca2+ low populations and blunting of this population and subsequent
enhanced stem cell maintenance upon NHE1 inhibition (Cariporide). Multi-omics analyses also identified enhancements in COVID19-related pathways in low O2 that corresponded
with enhanced expression of SARS-CoV-2 receptors/co-receptors, SARS-CoV-2 spike
protein (SP) binding, and expansion of SP-bound HSC/HSPCs in low O2 compared to air,
as well as enhanced stem cell maintenance of SP-bound, versus unbound, cells in low
O2.
Together, these data presented show low O2 harvest/retention of HSC/HSPCs
enhances stem cell maintenance, which could be utilized to improve HSC expansion, and
leads to differential pathway/signaling regulation of various biological pathways in
HSC/HSPCs including Ca2+ and SARS-CoV-2/viral infection that results in phenotypic and
functional consequences. / 2024-11-01
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/30485 |
| Date | 10 1900 |
| Creators | Dausinas, Paige Burke |
| Contributors | Elmendorf, Jeffrey, O'Leary, Heather, Bidwell, Joseph, Wan, Jun, Zhang, Ji |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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