Loss of Vascular Endothelial Growth Factor A (VEGFA) Isoforms in Granulosa Cells Using pDmrt-1-Cre or Amhr2-Cre Reduces Fertility by Arresting Follicular Development and by Reducing Litter Size in Female Mice

Abstract

Because VEGFA has been implicated in follicle development, the objective of this study was to determine the effects of granulosa- and germ cell-specific VEGFA loss on ovarian morphogenesis, function, and female fertility. pDmrt1-Cre mice were mated to floxed VEGFA mice to develop granulosa-/germ cell-specific knockouts (pDmrt1-Cre;Vegfa -/-). The time from mating to first parturition was increased when pDmrt1-Cre;Vegfa -/- females were mated to control males (P = 0.0008) and tended to be longer for heterozygous females (P < 0.07). Litter size was reduced for pDmrt1-Cre;Vegfa -/- females (P < 0.007). The time between the first and second parturitions was also increased for heterozygous females (P < 0.04) and tended to be increased for pDmrt1-Cre;Vegfa -/- females (P < 0.07). pDmrt1-Cre;Vegfa -/- females had smaller ovaries (P < 0.04), reduced plasma estradiol (P < 0.007), fewer developing follicles (P < 0.008) and tended to have fewer corpora lutea (P < 0.08). Expression of Igf1r was reduced (P < 0.05); expression of Foxo3a tended to be increased (P < 0.06); and both Fshr (P < 0.1) and Sirt6 tended to be reduced (P < 0.06) in pDmrt1-Cre;Vegfa -/- ovaries. To compare VEGFA knockouts, we generated Amhr2-Cre;Vegfa -/- mice that required more time from mating to first parturition (P < 0.003) with variable ovarian size. Both lines had more apoptotic granulosa cells, and vascular staining did not appear different. Taken together these data indicate that the loss of all VEGFA isoforms in granulosa/germ cells (proangiogenic and antiangiogenic) causes subfertility by arresting follicular development, resulting in reduced ovulation rate and fewer pups per litter.

The effects of flutamide on the neonatal rat hypothalamic–pituitary–adrenal and gonadal axes in response to hypoxia

“…Hypoxia has been shown to upregulate vascular endothelial growth factor (VEGF) in the swine granulosa cell (Basini et al, 2004). VEGF induces expression of 17ß-estradiol in mice granulosa cells and is a key mediator of follicle maturation (Sargent et al, 2015). Therefore, it is possible that our observation of increased estradiol in hypoxic rats is a result of increased VEGF or another similar factor, occurring independently of a rise in FSH.…”

Regulatory roles of ephrinA5 and its novel signaling pathway in mouse primary granulosa cell apoptosis and proliferation

“…Apoptosis and proliferation are crucial cellular physiological processes during ovarian follicular development [9,[37][38][39]. Notably, the crosstalk between cell death and survival signals is vital in regulating follicular cellular development and ultimately determines whether the follicles undergo atresia or ovulation, which is regulated by several ovarian factors [9,40].…”

Hormonal regulation of vascular endothelial growth factor A (VEGFA) gene expression in granulosa and theca cells of cattle1

“…Studies also show the presence of VEGFA in follicular fluid of cattle (Berisha et al, 2000(Berisha et al, , 2008Grazul-Bilska et al, 2007), pigs (Mattioli et al, 2001;Galeati et al, 2003), and humans (Friedman et al, 1997;Coppola et al, 2005) as well as the ability of bovine (Schams et al, 2001), primate (Duffy and Stouffer, 2003), and porcine (Galeati et al, 2003;Grasselli et al, 2010) GC from antral follicles to produce VEGFA in vitro. More recently, a study in mice showed that loss of VEGFA gene expression in GC arrests follicular development leading to decreased fertility (Sargent et al, 2015). However, the hormones and growth factors that regulate follicular VEGFA production in cattle is unknown, and therefore, additional studies are required to determine the hormonal control of VEGFA production in bovine GC and TC.…”