TY - JOUR
T1 - Vascular endothelial growth factor and angiopoietins during hen ovarian follicle development
AU - Kim, Dongwon
AU - Lee, Jeeyoung
AU - Johnson, A. L.
N1 - Funding Information:
This work was supported by the National Science Foundation (IOS-1354713) and the Walther H. Ott Endowment, The Pennsylvania State University to ALJ. We thank Dr. Olga Ocón-Grove and Ms. Renee Sydnor for technical assistance throughout these studies, and Dr. Morgan Benowitz-Fredericks for careful review of the manuscript.
Publisher Copyright:
© 2015 Elsevier Inc.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - Growth and maturation of ovarian follicles in the hen (Gallus gallus) requires a network of blood vessels that increases in complexity during development. The present studies investigate expression of vascular endothelial growth factor A (VEGF), angiopoietin1 (ANGPT1) and ANGPT2 mRNAs together with their associated receptors (VEGFR and TIE2, respectively) during maturation. Elevated expression of VEGF and its receptors is associated with healthy, compared to atretic, follicles. Levels of VEGF significantly increase, while antagonistic ANGPT2 decrease, in granulosa cells (GC) at follicle selection. By comparison, levels of VEGF, VEGFR1, VEGFR2, ANGPT1, ANGPT2 and TIE2 within the theca layer do not change (P > 0.05) relative to developmental stages surrounding follicle selection (6–8 mm versus 9–12 mm follicles). Prior to selection, treatment with transforming growth factor β1 (TGFβ1) significantly increases levels of VEGF in undifferentiated GC from prehierarchal (6–8 mm) follicles and actively differentiating GC from selected (9–12 and F4) follicles. Moreover, subsequent to selection follicle stimulating hormone (FSH) increases VEGF expression in GC from 9 to 12 mm follicles, and eventually luteinizing hormone (LH) promotes VEGF expression in GC from more mature preovulatory follicles. It is concluded that prior to follicle selection VEGF expression is regulated by autocrine and paracrine actions of TGFβ1 (but not FSH), and that a comparatively limited extent of vasculature is sufficient to maintain prehierarchal follicles in a viable and undifferentiated state. At follicle selection, FSH- and subsequently LH-induced VEGF production within the GC layer enhance angiogenesis within the theca layer, which facilitates the rapid growth of preovulatory follicles via enhanced incorporation of yellow yolk.
AB - Growth and maturation of ovarian follicles in the hen (Gallus gallus) requires a network of blood vessels that increases in complexity during development. The present studies investigate expression of vascular endothelial growth factor A (VEGF), angiopoietin1 (ANGPT1) and ANGPT2 mRNAs together with their associated receptors (VEGFR and TIE2, respectively) during maturation. Elevated expression of VEGF and its receptors is associated with healthy, compared to atretic, follicles. Levels of VEGF significantly increase, while antagonistic ANGPT2 decrease, in granulosa cells (GC) at follicle selection. By comparison, levels of VEGF, VEGFR1, VEGFR2, ANGPT1, ANGPT2 and TIE2 within the theca layer do not change (P > 0.05) relative to developmental stages surrounding follicle selection (6–8 mm versus 9–12 mm follicles). Prior to selection, treatment with transforming growth factor β1 (TGFβ1) significantly increases levels of VEGF in undifferentiated GC from prehierarchal (6–8 mm) follicles and actively differentiating GC from selected (9–12 and F4) follicles. Moreover, subsequent to selection follicle stimulating hormone (FSH) increases VEGF expression in GC from 9 to 12 mm follicles, and eventually luteinizing hormone (LH) promotes VEGF expression in GC from more mature preovulatory follicles. It is concluded that prior to follicle selection VEGF expression is regulated by autocrine and paracrine actions of TGFβ1 (but not FSH), and that a comparatively limited extent of vasculature is sufficient to maintain prehierarchal follicles in a viable and undifferentiated state. At follicle selection, FSH- and subsequently LH-induced VEGF production within the GC layer enhance angiogenesis within the theca layer, which facilitates the rapid growth of preovulatory follicles via enhanced incorporation of yellow yolk.
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U2 - 10.1016/j.ygcen.2015.11.017
DO - 10.1016/j.ygcen.2015.11.017
M3 - Article
C2 - 26996428
AN - SCOPUS:84975704403
SN - 0016-6480
VL - 232
SP - 25
EP - 31
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
ER -