title: Fatty acid degradation plays an essential role in proliferation of mouse female primordial germ cells via the p53-dependent cell cycle regulation.
abstract: Primordial germ cells (PGCs) are embryonic founders of germ cells that ultimately differentiate into oocytes and spermatogonia. Embryonic proliferation of PGCs starting from E11.5 ensures the presence of germ cells in adulthood, especially in female mammals whose total number of oocytes declines after this initial proliferation period. To better understand mechanisms underlying PGC proliferation in female mice, we constructed a proteome profile of female mouse gonads at E11.5. Subsequent KEGG pathway analysis of the 3,662 proteins profiled showed significant enrichment of pathways involved in fatty acid degradation. Further, the number of PGCs found in in vitro cultured fetal gonads significantly decreased with application of etomoxir, an inhibitor of the key rate-limiting enzyme of fatty acid degradation carnitine acyltransferase I (CPT1). Decrease in PGCs was further determined to be the result of reduced proliferation rather than apoptosis. The inhibition of fatty acid degradation by etomoxir has the potential to activate the Ca(2+)/CamKII/5'-adenosine monophosphate-activated protein kinase (AMPK) pathway; while as an upstream activator, activated AMPK can function as activator of p53 to induce cell cycle arrest. Thus, we detected the expressional level of AMPK, phosphorylated AMPK (P-AMPK), phosphorylated p53 (P-p53) and cyclin-dependent kinase inhibitor 1 (p21) by Western blots, the results showed increased expression of them after treatment with etomoxir, suggested the activation of p53 pathway was the reason for reduced proliferation of PGCs. Finally, the involvement of p53-dependent G1 cell cycle arrest in defective proliferation of PGCs was verified by rescue experiments. Our results demonstrate that fatty acid degradation plays an important role in proliferation of female PGCs via the p53-dependent cell cycle regulation.
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Teng
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Sui
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhou
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Cong
authors.initials: C
authors.lastname: Shen
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yang
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Pang
authors.initials: P
authors.lastname: Zhang
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Xuejiang
authors.initials: X
authors.lastname: Guo
authors.affiliation: a State Key Laboratory of Reproductive Medicine , Department of Histology and Embryology, Nanjing Medical University , Nanjing , P.R. China.
authors.forename: Ran
authors.initials: R
authors.lastname: Huo
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D002334:Carnitine O-Palmitoyltransferase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004852:Epoxy Compounds / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D004791:Enzyme Inhibitors; D004852:Epoxy Compounds; D005227:Fatty Acids; D020033:Protein Isoforms; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D002334:Carnitine O-Palmitoyltransferase; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D055372:AMP-Activated Protein Kinases; C054207:etomoxir; D002118:Calcium
keywords: Primordial germ cells (PGCs); carnitine acyltransferase I A (CPT1A); fatty acid degradation; p53-depedent G1 arrest; proliferation