Defining an EPOR- regulated transcriptome for primary progenitors, including Tnfr-sf13c as a novel mediator of EPO- dependent erythroblast formation.
Certain concepts concerning EPO/EPOR action modes have been challenged by in vivo studies: Bcl-x levels are elevated in maturing erythroblasts, but not in their progenitors; truncated EPOR alleles that lack a major p85/PI3K recruitment site nonetheless promote polycythemia; and Erk1 disruption unexpectedly bolsters erythropoiesis. To discover novel EPO/EPOR action routes, global transcriptome analyses presently are applied to interrogate EPO/EPOR effects on primary bone marrow-derived CFUe-like progenitors. Overall, 160 EPO/EPOR target transcripts were significantly modulated 2-to 21.8-fold. A unique set of EPO-regulated survival factors included Lyl1, Gas5, Pim3, Pim1, Bim, Trib3 and Serpina 3g. EPO/EPOR-modulated cell cycle mediators included Cdc25a, Btg3, Cyclin-d2, p27-kip1, Cyclin-g2 and CyclinB1-IP-1. EPO regulation of signal transduction factors was also interestingly complex. For example, not only Socs3 plus Socs2 but also Spred2, Spred1 and Eaf1 were EPO-induced as negative-feedback components. Socs2, plus five additional targets, further proved to comprise new EPOR/Jak2/Stat5 response genes (which are important for erythropoiesis during anemia). Among receptors, an atypical TNF-receptor Tnfr-sf13c was up-modulated >5-fold by EPO. Functionally, Tnfr-sf13c ligation proved to both promote proerythroblast survival, and substantially enhance erythroblast formation. The EPOR therefore engages a sophisticated set of transcriptome response circuits, with Tnfr-sf13c deployed as one novel positive regulator of proerythroblast formation.
Center of Excellence in Stem Cell Biology and Regenerative Medicine Maine Medical Center Research Institute, Scarborough, Maine, United States of America.
Seema
S
Singh
Arvind
A
Dev
Rakesh
R
Verma
Anamika
A
Pradeep
Pradeep
P
Sathyanarayana
Jennifer M
JM
Green
Aishwarya
A
Narayanan
Don M
DM
Wojchowski
D000818:Animals; D001853:Bone Marrow / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D004900:Erythroblasts / Q000166:cytology / Q000378:metabolism*; D004920:Erythropoiesis / Q000235:genetics*; D004921:Erythropoietin / Q000378:metabolism / Q000494:pharmacology; D005786:Gene Expression Regulation; D055879:Gene Knock-In Techniques; D051379:Mice; D008822:Mice, Transgenic; D020033:Protein Isoforms / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics*; D017467:Receptors, Erythropoietin / Q000235:genetics* / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D059467:Transcriptome
D018797:Cell Cycle Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D018124:Receptors, Tumor Necrosis Factor; D004921:Erythropoietin