FGF2/FGFR signaling promotes cumulus-oocyte complex maturation in vitro
Chao Du1,2, John S Davis3,4, Chao Chen1,2
1Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Wuhan, China.
Reproduction (Cambridge, England)
|January 12, 2021
Summary
Fibroblast growth factor 2 (FGF2) signaling in mouse cumulus-oocyte complexes (COCs) is crucial for oocyte meiosis and cumulus expansion during in vitro maturation (IVM). FGF2 from cumulus cells regulates this process via an autocrine/paracrine loop.
Area of Science:
- Reproductive Biology
- Cell Signaling
- Developmental Biology
Background:
- Fibroblast growth factor 2 (FGF2) and its receptors (FGFR) are vital for somatic cell functions.
- The specific roles of FGF2/FGFR in oocyte meiosis remain largely unexplored.
- Understanding these pathways is key to improving in vitro maturation techniques.
Purpose of the Study:
- To investigate the expression patterns and functional roles of FGF2/FGFR during mouse in vitro maturation (IVM) of cumulus-oocyte complexes (COCs).
- To elucidate the involvement of FGF2/FGFR signaling in oocyte meiotic progression and cumulus expansion.
Main Methods:
- Quantitative analysis of Fgf2 and Ffgr1 transcripts during IVM of COCs.
- Pharmacological inhibition of FGFR using SU5402.
- Supplementation with FGF2.
- Assessment of oocyte meiotic progression and cumulus expansion.
- Analysis of key gene expression related to oocyte and cumulus function.
Main Results:
- Fgf2 and Ffgr1 transcripts increased during IVM, with Fgfr1 abundant in oocytes and cumulus cells, and Fgf2 in cumulus cells.
- FGFR inhibition blocked oocyte meiosis and cumulus expansion, downregulating Bmp15, Gdf9, Ptx3, Has2, and Tnfaip6.
- FGF2 supplementation promoted meiotic progression and upregulated Bmp15, Gdf9, Ptx3, and Has2.
- FGF2/FGFR signaling impacted the c-Mos/MAPK pathway and maturation-promoting factor (MPF).
Conclusions:
- FGF2 produced by cumulus cells activates an FGF2/FGFR autocrine/paracrine loop within COCs.
- This signaling pathway is essential for regulating cumulus expansion and oocyte meiosis during IVM.
- These findings highlight a novel role for FGF2/FGFR signaling in COC maturation.
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