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Ovarian follicular cells have innate immune capabilities that modulate their endocrine function.

Herath S, Williams EJ, Lilly ST, Gilbert RO, Dobson H, Bryant CE, Sheldon IM - Reproduction (2007)

Bottom Line: Many of the effects of E. coli are mediated by its surface molecule lipopolysaccharide (LPS) binding to the Toll-like receptor-4 (TLR4), CD14, MD-2 receptor complex on immune cells, but immune cells are not present inside ovarian follicles.Furthermore, these cells expressed TLR4, CD14 and MD-2 transcripts throughout the key stages of follicle growth and development.It appears that granulosa cells have an immune capability to detect bacterial infection, which perturbs follicle steroidogenesis, and this is a likely mechanism by which ovarian follicle growth and function is perturbed during bacterial infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Clinical Sciences, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK.

ABSTRACT
Oestrogens are pivotal in ovarian follicular growth, development and function, with fundamental roles in steroidogenesis, nurturing the oocyte and ovulation. Infections with bacteria such as Escherichia coli cause infertility in mammals at least in part by perturbing ovarian follicle function, characterised by suppression of oestradiol production. Ovarian follicle granulosa cells produce oestradiol by aromatisation of androstenedione from the theca cells, under the regulation of gonadotrophins such as FSH. Many of the effects of E. coli are mediated by its surface molecule lipopolysaccharide (LPS) binding to the Toll-like receptor-4 (TLR4), CD14, MD-2 receptor complex on immune cells, but immune cells are not present inside ovarian follicles. The present study tested the hypothesis that granulosa cells express the TLR4 complex and LPS directly perturbs their secretion of oestradiol. Granulosa cells from recruited or dominant follicles are exposed to LPS in vivo and when they were cultured in the absence of immune cell contamination in vitro they produced less oestradiol when challenged with LPS, although theca cell androstenedione production was unchanged. The suppression of oestradiol production by LPS was associated with down-regulation of transcripts for aromatase in granulosa cells, and did not affect cell survival. Furthermore, these cells expressed TLR4, CD14 and MD-2 transcripts throughout the key stages of follicle growth and development. It appears that granulosa cells have an immune capability to detect bacterial infection, which perturbs follicle steroidogenesis, and this is a likely mechanism by which ovarian follicle growth and function is perturbed during bacterial infection.

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Analysis of gene expression by granulosa cells associated with reproductive function. Granulosa cells isolated from medium (4–8 mm diameter) or large (>8 mm diameter) follicles were stimulated with 10 μg/ml LPS for 48 h and harvested, RNA was isolated and reverse transcribed as described in Materials and Methods. cDNA was analysed for the presence of (A) aromatase, FSHR, LHR, ERα, and (B) NOS2, IL-1α and TNFα transcripts using the indicated primer pairs (Table 1). A representative result is shown (n=3). (C) PCR bands were analysed and are represented as LPS treatment (open bar) relative to nil control (closed bar) for granulosa cells isolated from large (>8 mm diameter) follicles. Results are presented as the mean+s.e.m. of three experiments. *P<0.05 compared with control.
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fig4: Analysis of gene expression by granulosa cells associated with reproductive function. Granulosa cells isolated from medium (4–8 mm diameter) or large (>8 mm diameter) follicles were stimulated with 10 μg/ml LPS for 48 h and harvested, RNA was isolated and reverse transcribed as described in Materials and Methods. cDNA was analysed for the presence of (A) aromatase, FSHR, LHR, ERα, and (B) NOS2, IL-1α and TNFα transcripts using the indicated primer pairs (Table 1). A representative result is shown (n=3). (C) PCR bands were analysed and are represented as LPS treatment (open bar) relative to nil control (closed bar) for granulosa cells isolated from large (>8 mm diameter) follicles. Results are presented as the mean+s.e.m. of three experiments. *P<0.05 compared with control.

Mentions: To determine whether the decrease in oestradiol production in granulosa cells from medium and large follicles was due to changes in responsiveness to FSH and/or the down-regulation of the enzyme required for oestradiol synthesis, expression of mRNA for the FSH receptor (FSHR) and aromatase were analysed. Following LPS challenge of granulosa cells isolated from dominant (>8 mm) follicles, only aromatase mRNA levels were down-regulated (Fig. 4A and C; FSHR, P=0.11). Analysis of oestradiol receptor α (ERα), ERβ and LH receptor (LHR) mRNA expression was determined to explore the effects of LPS on granulosa cell function. Granulosa cells isolated from recruited and dominant follicles expressed ERα mRNA, while only granulosa cells isolated from dominant follicles expressed LHR mRNA and expression was not affected by LPS treatment (Fig. 4A). Transcripts for ERβ mRNA were not detectable in control or LPS-treated granulosa cells at 48 h, but were expressed at 0 h by freshly isolated granulosa cells (data not shown).


Ovarian follicular cells have innate immune capabilities that modulate their endocrine function.

Herath S, Williams EJ, Lilly ST, Gilbert RO, Dobson H, Bryant CE, Sheldon IM - Reproduction (2007)

Analysis of gene expression by granulosa cells associated with reproductive function. Granulosa cells isolated from medium (4–8 mm diameter) or large (>8 mm diameter) follicles were stimulated with 10 μg/ml LPS for 48 h and harvested, RNA was isolated and reverse transcribed as described in Materials and Methods. cDNA was analysed for the presence of (A) aromatase, FSHR, LHR, ERα, and (B) NOS2, IL-1α and TNFα transcripts using the indicated primer pairs (Table 1). A representative result is shown (n=3). (C) PCR bands were analysed and are represented as LPS treatment (open bar) relative to nil control (closed bar) for granulosa cells isolated from large (>8 mm diameter) follicles. Results are presented as the mean+s.e.m. of three experiments. *P<0.05 compared with control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2735812&req=5

fig4: Analysis of gene expression by granulosa cells associated with reproductive function. Granulosa cells isolated from medium (4–8 mm diameter) or large (>8 mm diameter) follicles were stimulated with 10 μg/ml LPS for 48 h and harvested, RNA was isolated and reverse transcribed as described in Materials and Methods. cDNA was analysed for the presence of (A) aromatase, FSHR, LHR, ERα, and (B) NOS2, IL-1α and TNFα transcripts using the indicated primer pairs (Table 1). A representative result is shown (n=3). (C) PCR bands were analysed and are represented as LPS treatment (open bar) relative to nil control (closed bar) for granulosa cells isolated from large (>8 mm diameter) follicles. Results are presented as the mean+s.e.m. of three experiments. *P<0.05 compared with control.
Mentions: To determine whether the decrease in oestradiol production in granulosa cells from medium and large follicles was due to changes in responsiveness to FSH and/or the down-regulation of the enzyme required for oestradiol synthesis, expression of mRNA for the FSH receptor (FSHR) and aromatase were analysed. Following LPS challenge of granulosa cells isolated from dominant (>8 mm) follicles, only aromatase mRNA levels were down-regulated (Fig. 4A and C; FSHR, P=0.11). Analysis of oestradiol receptor α (ERα), ERβ and LH receptor (LHR) mRNA expression was determined to explore the effects of LPS on granulosa cell function. Granulosa cells isolated from recruited and dominant follicles expressed ERα mRNA, while only granulosa cells isolated from dominant follicles expressed LHR mRNA and expression was not affected by LPS treatment (Fig. 4A). Transcripts for ERβ mRNA were not detectable in control or LPS-treated granulosa cells at 48 h, but were expressed at 0 h by freshly isolated granulosa cells (data not shown).

Bottom Line: Many of the effects of E. coli are mediated by its surface molecule lipopolysaccharide (LPS) binding to the Toll-like receptor-4 (TLR4), CD14, MD-2 receptor complex on immune cells, but immune cells are not present inside ovarian follicles.Furthermore, these cells expressed TLR4, CD14 and MD-2 transcripts throughout the key stages of follicle growth and development.It appears that granulosa cells have an immune capability to detect bacterial infection, which perturbs follicle steroidogenesis, and this is a likely mechanism by which ovarian follicle growth and function is perturbed during bacterial infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Clinical Sciences, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK.

ABSTRACT
Oestrogens are pivotal in ovarian follicular growth, development and function, with fundamental roles in steroidogenesis, nurturing the oocyte and ovulation. Infections with bacteria such as Escherichia coli cause infertility in mammals at least in part by perturbing ovarian follicle function, characterised by suppression of oestradiol production. Ovarian follicle granulosa cells produce oestradiol by aromatisation of androstenedione from the theca cells, under the regulation of gonadotrophins such as FSH. Many of the effects of E. coli are mediated by its surface molecule lipopolysaccharide (LPS) binding to the Toll-like receptor-4 (TLR4), CD14, MD-2 receptor complex on immune cells, but immune cells are not present inside ovarian follicles. The present study tested the hypothesis that granulosa cells express the TLR4 complex and LPS directly perturbs their secretion of oestradiol. Granulosa cells from recruited or dominant follicles are exposed to LPS in vivo and when they were cultured in the absence of immune cell contamination in vitro they produced less oestradiol when challenged with LPS, although theca cell androstenedione production was unchanged. The suppression of oestradiol production by LPS was associated with down-regulation of transcripts for aromatase in granulosa cells, and did not affect cell survival. Furthermore, these cells expressed TLR4, CD14 and MD-2 transcripts throughout the key stages of follicle growth and development. It appears that granulosa cells have an immune capability to detect bacterial infection, which perturbs follicle steroidogenesis, and this is a likely mechanism by which ovarian follicle growth and function is perturbed during bacterial infection.

Show MeSH
Related in: MedlinePlus