Steroidogenesis, proliferation and apoptosis in bovine granulosa cells: role of tumour necrosis factor-alpha and its possible signalling mechanisms.
This study was designed to investigate the presence of bioactive tumour necrosis factor-alpha (TNF-alpha) in bovine fluid collected from small (<5 mm) and large (>8 mm) follicles, as well as the production of the cytokine by the granulosa cells collected from the same type of follicles. Moreover, the effectiveness of 10, 1 and 0.1 ng mL(-1) of human TNF-alpha (hTNF-alpha) in affecting the main parameters of granulosa cell function, progesterone (P4) and oestradiol-17beta (E2) production, cell proliferation and apoptosis, was tested. In addition, the study aimed to determine whether the signalling mechanisms of TNF-alpha in these cells involve cAMP, nitric oxide or prostaglandin E2 (PGE2) and F2alpha (PGF2alpha). It emerged that bioactive TNF-alpha is present in follicular fluid from both types of follicles and can be measured in media conditioned by granulosa cells from large follicles. As for the effects of hTNF-alpha, it inhibits P4 production in cells from both types of follicles and stimulates E2 output in those from small follicles; it does not affect proliferation, but it stimulates granulosa cell apoptosis. Finally, the effects of hTNF-alpha on bovine granulosa cells are not mediated by nitric oxide or cAMP, as neither of these substances were affected by treatment with the cytokine; however, in some way, they could be mediated through PGE2 and PGF2alpha, the production of which was inhibited by TNF-alpha in cells from small follicles.
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Dipartimento di Produzioni Animali, Biotecnologie Veterinarie, Qualità e Sicurezza degli Alimenti-Sezione di Fisiologia Veterinaria, Università di Parma, Italy.
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D000818:Animals; D017209:Apoptosis; D002417:Cattle; D002455:Cell Division; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000032:analysis; D000242:Cyclic AMP / Q000378:metabolism; D015237:Dinoprost / Q000096:biosynthesis; D015232:Dinoprostone / Q000096:biosynthesis; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry; D006107:Granulosa Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis; D015398:Signal Transduction; D013256:Steroids / Q000096:biosynthesis*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000494:pharmacology / Q000502:physiology*
D017077:Culture Media, Conditioned; D013256:Steroids; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D011374:Progesterone; D004958:Estradiol; D015237:Dinoprost; D000242:Cyclic AMP; D015232:Dinoprostone