Common and distinct factors regulate expression of mRNA for ETV5 and GDNF, Sertoli cell proteins essential for spermatogonial stem cell maintenance.
Ets variant gene 5 (ETV5) and glial cell-derived neurotrophic factor (GDNF) are produced in Sertoli cells and required for maintenance and self-renewal of spermatogonial stem cells (SSCs) in mice. Fibroblast growth factors (FGFs) have been reported to stimulate Etv5 mRNA expression, and FSH was shown to stimulate Gdnf mRNA in Sertoli cell cultures, but there is no other information on factors that regulate these key Sertoli cell proteins necessary for stem cell maintenance. In this study, we investigated regulation of ETV5 and GDNF using the TM4 murine Sertoli cell line. FGF2 stimulated a time- and dose-dependent increase in Etv5 mRNA expression, with a maximal 8.3-fold increase at 6 h following 25 ng/ml FGF2 treatment. This FGF2 dose also stimulated Gdnf mRNA at 48 h. FGF2 effects on Etv5 and Gdnf mRNA were partially mediated through mitogen-activated protein kinase (MAPK) and phosphatidyl inositol 3-kinase (PI3K)-signaling cascades. Specific inhibitors of MAPK (PD98059) and PI3K (wortmannin) pathways reduced Etv5 and Gdnf mRNA expression in FGF2-treated cells. Epidermal growth factor (EGF) stimulated Etv5 mRNA but not Gdnf mRNA. TNFalpha and IL-1beta stimulated Gdnf mRNA, but had no effect on Etv5 mRNA. Other hormonal regulators of Sertoli cells such as testosterone, triiodothyronine and activin A did not affect Etv5 or Gdnf mRNA expression. Results with primary Sertoli cell cultures confirmed findings obtained with the TM4 cell line, validating the use of the TM4 model to examine regulation of Etv5 and Gdnf mRNA expression. In conclusion, we have identified common and unique pathways that regulate Etv5 and Gdnf mRNA in Sertoli cells, and FGFs are emerging as key regulators of the Sertoli cell proteins that control SSCs.
Simon
Liz
L
Department of Veterinary Biosciences, University of Illinois at Urbana-Champaign, 2001 S. Lincoln Ave, Urbana, IL 61802, USA.
Ekman
Gail C
GC
Tyagi
Gaurav
G
Hess
Rex A
RA
Murphy
Kenneth M
KM
Cooke
Paul S
PS
D028341:Activins / Q000378:metabolism; D000730:Androstadienes / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism; D005786:Gene Expression Regulation; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012708:Sertoli Cells / Q000166:cytology / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013093:Spermatogonia / Q000166:cytology / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D013739:Testosterone / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D000077191:Wortmannin
D000730:Androstadienes; D004268:DNA-Binding Proteins; C513242:Etv5 protein, mouse; D005419:Flavonoids; D051100:Glial Cell Line-Derived Neurotrophic Factor; D053583:Interleukin-1beta; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; C422405:activin A; D014284:Triiodothyronine; D016222:Fibroblast Growth Factor 2; D028341:Activins; D013739:Testosterone; D004815:Epidermal Growth Factor; D019869:Phosphatidylinositol 3-Kinases; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin