Role of retinoic acid and platelet-derived growth factor receptor cross talk in the regulation of neonatal gonocyte and embryonal carcinoma cell differentiation.
Neonatal gonocytes are direct precursors of spermatogonial stem cells, the cell pool that supports spermatogenesis. Although unipotent in vivo, gonocytes express pluripotency genes common with embryonic stem cells. Previously, we found that all-trans retinoic acid (RA) induced the expression of differentiation markers and a truncated form of platelet-derived growth factor receptor (PDGFR)β in rat gonocytes, as well as in F9 mouse embryonal carcinoma cells, an embryonic stem cell-surrogate that expresses somatic lineage markers in response to RA. The present study is focused on identifying the signaling pathways involved in RA-induced gonocyte and F9 cell differentiation. Mitogen-activated protein kinase kinase (MEK) 1/2 activation was required during F9 cell differentiation towards somatic lineage, whereas its inhibition potentiated RA-induced Stra8 expression, suggesting that MEK1/2 acts as a lineage specification switch in F9 cells. In both cell types, RA increased the expression of the spermatogonial/premeiotic marker Stra8, which is in line with F9 cells being at a stage before somatic-germline lineage specification. Inhibiting PDGFR kinase activity reduced RA-induced Stra8 expression. Interestingly, RA increased the expression of PDGFRα variant forms in both cell types. Together, these results suggest a potential cross talk between RA and PDGFR signaling pathways in cell differentiation. RA receptor-α inhibition partially reduced RA effects on Stra8 in gonocytes, indicating that RA acts in part via RA receptor-α. RA-induced gonocyte differentiation was significantly reduced by inhibiting SRC (v-src avian sarcoma [Schmidt-Ruppin A-2] viral oncogene) and JAK2/STAT5 (Janus kinase 2/signal transducer and activator of transcription 5) activities, implying that these signaling molecules play a role in gonocyte differentiation. These results suggest that gonocyte and F9 cell differentiation is regulated via cross talk between RA and PDGFRs using different downstream pathways.
The Research Institute of the McGill University Health Centre (G.M., V.M., A.B., M.C.), Montreal, Quebec, Canada H3G1A4; Departments of Pharmacology and Therapeutics (G.M., M.C.) Medicine (M.C.), McGill University, Montreal, Quebec, Canada H3G1A4; Department of Biochemistry and Molecular and Cellular Biology (Y.W.), Georgetown University Medical Center, Washington, DC 20057; and Protein Characterization Laboratory (X.Y., J.B.), Cancer Research Technology Program, Leidos Biomedical Research, Inc, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland 21702.
Gurpreet
G
Manku
Yan
Y
Wang
Vanessa
V
Merkbaoui
Annie
A
Boisvert
Xiaoying
X
Ye
Josip
J
Blonder
Martine
M
Culty
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D053687:Adult Stem Cells / Q000166:cytology / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D054278:Embryonal Carcinoma Stem Cells / Q000166:cytology* / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D007641:Keratolytic Agents / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D010982:Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000254:growth & development; D014212:Tretinoin / Q000494:pharmacology*
D048868:Adaptor Proteins, Signal Transducing; D007641:Keratolytic Agents; D010982:Platelet-Derived Growth Factor; C102019:Stra8 protein, mouse; D014212:Tretinoin; D020797:Receptor, Platelet-Derived Growth Factor beta; D048049:Extracellular Signal-Regulated MAP Kinases; D020930:MAP Kinase Kinase Kinases