Effect of local neutralization of basic fibroblast growth factor or vascular endothelial growth factor by a specific antibody on the development of the corpus luteum in the cow

When given intravenously (iv), lipopolysaccharide (LPS) transiently suppresses the structure and function of the bovine corpus luteum (CL). This is associated with increased release of prostaglandin (PG) F 2a metabolite. The underlying regulatory mechanisms of this process remain, however, obscure. Therefore, the aims of this study were: i) to investigate the expression of the LPS receptor toll-like receptor 4 (TLR4) and 2 (TLR2) in the bovine CL during early, mid-and late luteal phases; and ii) to further dissect the mechanisms of LPS-mediated suppression of luteal function. As revealed by semi-quantitative qPCR and immunohistochemistry, both receptors were detectable throughout the luteal lifespan. Their mRNA levels increased from the early toward the mid-luteal phase; no further changes were observed thereafter. The TLR4 protein seemed more highly represented than TLR2. The cellular localization of TLRs was in blood vessels; weaker signals were observed in luteal cells. Additionally, cows were treated either with LPS (iv, 0.5 mg/kg BW) or with saline on Day 10 after ovulation. Samples were collected 1200 h after treatment and on Day 10 of the respective subsequent (untreated) cycle. The mRNA expression of several possible regulatory factors was investigated, revealing the suppression of PGF 2a receptor (PTGFR), STAR protein and 3b-hydroxysteroid dehydrogenase, compared with controls and subsequent cycles. The expression of TLR2 and TLR4, interleukin 1a (IL1A) and 1b (IL1B) and of PGF 2a and PGE 2 synthases (HSD20A and mPTGES respectively) was increased. The results demonstrate the presence of TLR2 and TLR4 in the bovine CL, and implicate their possible involvement in the deleterious effects of LPS on its function.

Section: Discussionmentioning

confidence: 99%

LPS-mediated effects and spatio-temporal expression of TLR2 and TLR4 in the bovine corpus luteum

Lüttgenau¹,

Herzog²,

Strüve³

et al. 2016

“…The inhibition of VEGFA, FGF2 or PDGF action in vivo is associated with attenuated progesterone secretion resulting from changes in gross luteal structure, function and angiogenesis in the mouse, macaque and cow (Zimmermann et al 2001, Fraser et al 2005, Kuhnert et al 2008, Yamashita et al 2008. VEGFA and FGF2 stimulated progesterone release from microdialysed bovine early CL in vitro (Kobayashi et al 2001).…”

Section: Discussionmentioning

confidence: 99%

“…We have recently shown that FGF2 protein levels are particularly high during the follicular-luteal transition, suggesting an important role for FGF2 during the development of the early bovine CL (Robinson et al 2007). Furthermore, injections of FGF2 antibody directly into the bovine CL decreased luteal volume and progesterone production (Yamashita et al 2008).…”

Section: Introductionmentioning

confidence: 98%

“…Both receptors have been localised to microvascular endothelial cells of the bovine CL (Gabler et al 2004) with expression shown throughout the luteal phase (Berisha et al 2000). The inhibition of VEGFA action in vivo with antibody or antagonist treatment against VEGFA or VEGFR2 in a number of species results in the profound inhibition of luteal function and angiogenesis, as evidenced by reductions in the number, size and vascularity of corpora lutea and resultant attenuated progesterone secretion (Zimmermann et al 2001, Fraser et al 2005, Yamashita et al 2008.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

FGF2 is crucial for the development of bovine luteal endothelial networks in vitro

Woad¹,

Hammond²,

Mann³

et al. 2009

The development of the corpus luteum requires angiogenesis, and involves the complex interplay between factors such as vascular endothelial growth factor A (VEGFA), fibroblast growth factor 2 (FGF2) and platelet-derived growth factor (PDGF). However, the relative role of these factors remains to be elucidated. This study used a new physiologically relevant mixed luteal cell culture system to test the hypotheses that: a) FGF2 and VEGFA are critical for bovine luteal angiogenesis; and b) local luteal PDGF signalling stimulates the formation of endothelial networks. Cells were treated with receptor tyrosine kinase inhibitors against VEGFA (SU1498), FGF2 (SU5402) or PDGF (AG1295) activity. After 9 days in culture, endothelial cells were immunostained for von Willebrand factor (VWF) and quantified by image analysis. Highly organised intricate endothelial networks were formed in the presence of exogenous VEGFA and FGF2. The inhibition of FGF2 activity reduced the total area of VWF staining versus controls (O95%; P!0.001). Inhibition of VEGF and PDGF activity reduced the endothelial network formation by more than 60 and 75% respectively (P!0.05). Progesterone production increased in all treatments from day 1 to 7 (P!0.001), and was unaffected by FGF2 or PDGF receptor kinase inhibition (PO0.05), but was reduced by the VEGF receptor inhibitor on days 5 and 7 (P!0.001). In conclusion, this study confirmed that VEGF signalling regulates both bovine luteal angiogenesis and progesterone production. However, FGF2 was crucial for luteal endothelial network formation. Also, for the first time, this study showed that local luteal PDGF activity regulates bovine luteal endothelial network formation in vitro.

“…Zeleznik et al (1981) suggested that the selected follicles possess more elaborate microvasculature than other follicles. We concluded from studies in cow that vascular endothelial growth factor (VEGFA) and fibroblast growth factor 2 (FGF2) are involved in the proliferation of capillaries that accompany the selection of the preovulatory follicle resulting in an increased supply of nutrients, precursors and hormones, and therefore supporting the growth of the dominant follicle (Berisha et al 2000a, Yamashita et al 2008.…”

Section: Introductionmentioning

confidence: 99%

Expression and possible role of fibroblast growth factor family members in porcine antral follicles during final maturation

Schams

Steinberg²,

Šteffl³

et al. 2009

Self Cite

The aim of this study was to investigate the possible participation of fibroblast growth factor (FGF) family members (FGF1, FGF2 and FGF7 and their receptors) in porcine follicles (polyovulatory species) under special consideration for FGF2 during final growth. A classification of follicles was done by size and follicular fluid content of oestradiol-17b, progesterone and prostaglandin F2a. The mRNA expression of examined factors was analysed by real-time PCR. The hormone concentration was estimated by enzyme immunoassay, protein characterisation by western blotting and localisation by immunohistochemistry. Follicle tissue separated in theca interna and granulosa cells was extracted and tested for mRNA of FGF1, FGF2, FGF7 and receptors (FGFR1IIIc, FGFRIIIb and FGFR2IIIc). Additionally, the mRNA expression of FSHR, LHR and aromatase cytochrome P450 for further characterisation of follicles was analysed. Significantly, higher FGF2 protein levels were measured in stroma when compared with total follicle or corpus luteum tissue. This result was confirmed by western blot with two strong bands. Immunological localisation of FGF2 only in stroma (fibroblasts) confirms the protein measurements. The results show a clear difference for FGF2 protein expression during final growth of follicles if monovulatory (bovine) and polyovulatory (porcine) species are compared. FGF2 protein in porcine ovary may be (due to localisation and concentration in stroma) important for support of angiogenesis of more follicles (polyovulatory species) and not of a single follicle like in cows.