Macrophages: a source of luteotropic cybernins.
ABSTRACT A macrophage homogenate contained substances which stimulated primary cultures of mouse granulosa cells to secrete more progesterone. The response to the luteotropic substances was similar to that observed when intact macrophages were co-cultured with granulosa cells. The bioactive polypeptides present in cytosolic and particulate fractions of cell homogenates were non-dialyzable, heat labile and trypsin sensitive. When the surface of intact macrophages was treated with trypsin there was a loss of activity from the particulate fraction suggesting that some luteotropic proteins reside on the plasma membrane of mononuclear phagocytes. Treatment of macrophages with Con A but not the succinyl derivative of the lectin caused a release of luteotropic proteins with apparent molecular weights of 26,000 and 41,000. These findings in conjunction with our prior observation that macrophages must contact granulosa cells to stimulate progesterone secretion suggest that aggregation of mononuclear cell surface proteins may occur when the two cells interact thus resulting in the expression of luteotropic activity. Hence, it appears that macrophages which are found within corpus luteum may be a source of ovarian cybernins. This is the first description that a cell of the immune system can communicate at the molecular level with a steroid secreting cell of the ovary.
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ABSTRACT: Tumor necrosis factor- (TNF-), a cytokine which is produced by activated macrophages, has been shown to participate in the regulation of ovarian functions. In the course of our investigation on the mechanism of maturation, fertilization and degeneration of mouse oocytes, immunoreactivity to TNF- was found in the cytoplasm of the cells surrounding the maturing oocytes and of granulosa cells facing the antral cavity. Immunoblot analysis with the specific antibody to TNF- identified the 17 kDa Mr band in the extract of cumulusoocyte complexes. Various concentrations of TNF- (mouse, recombinant) and anti TNF- antiserum (polyclonal rabbit anti-mouse recombinant TNF-) were then used to determine their effect on the germinal vesicle breakdown (GVBD), polar body extrusion, fertilization and fragmentation of mouse oocytes/eggs. TNF- at concentrations of 10 ng/mL or less and anti-TNF- antiserum at concentrations of 10% or less, had no effect on the spontaneous GVBD and polar body extrusion of mouse oocytes in culture. Mouse follicular oocytes cultured for more than 72 h in modified Krebs-Ringer solution in vitro undergo spontaneous fragmentation, which is a degenerative change to form ‘blastomeres’ with or without nuclear fragments or chromatin. Ghost-like blastomeres were also identified in the space among fragmented ‘blastomeres’. The spontaneous fragmentation of mouse follicular oocytes was suppressed in the presence of TNF- at concentrations of 1 ng/mL or greater. Anti-TNF- antiserum (1%) accelerated the induction of fragmentation of oocytes cultured in vitro. The addition of anti TNF- antiserum (10%) to the culture medium did not influence the fertilization rates of the eggs surrounded by the expanded cumulus. These results appear to indicate that the process of degeneration of mouse oocytes/eggs is modulated by TNF- accumulated in the expanded cumulus during oocyte maturation.Embryologia 10/2003; 37(4):413 - 420. · 2.21 Impact Factor
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ABSTRACT: Unstimulated macrophages from testes inhibited the production of testosterone by Leydig cells from adult, but not immature, Sprague-Dawley rats (significant after 48 h). Similar results were observed with unstimulated macrophage-conditioned media, suggesting that the observed effect was mediated by one or more secretory products. None of these substances was interleukin-1, since macrophage supernatants tested negative in an interleukin-1 alpha and interleukin-1 beta sensitive, thymocyte assay. Interleukin-6 was detected by a B cell proliferation assay. After stimulation by LPS, testicular macrophages enhanced testosterone production by Leydig cells from adult and immature rats. This enhancement was dose-dependent and required low concentrations (but over 2.5%) of conditioned media. Interleukin-1 and interleukin-6 activities were detected in LPS-stimulated macrophage supernatants. Supernatants of LPS-stimulated, human monocytes had similar effects on Leydig cells. They were rich in interleukin-1, interleukin-1 receptor antagonist and interleukin-6. The present study suggests that, in adult rats, testicular macrophages modulate Leydig cell steroidogenesis by secretory products whose secretion depends on the physiological state of macrophages. The factor or factors responsible for stimulation are not species-specific. The effect cannot be accounted for by variations in the concentration of the above mentioned interleukins in macrophage supernatants.Andrologia 01/2009; 30(2):71-8. · 1.75 Impact Factor
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ABSTRACT: Innovations in in vitro ovarian follicle culture have revolutionized the field of fertility preservation, but the successful culturing of isolated primary and small secondary follicles remains difficult. Herein, we describe a revised 3D culture system that uses a feeder layer of ovarian stromal cells to support early follicle development. This culture system allows significantly improved primary and early secondary follicle growth and survival. The stromal cells, consisting mostly of thecal cells and ovarian macrophages, recapitulate the in vivo conditions of these small follicles and increase the production of androgens and cytokines missing from stromal cell-free culture conditions. These results demonstrate that small follicles have a stage-specific reliance on the ovarian environment, and that growth and survival can be improved in vitro through a milieu created by pre-pubertal ovarian stromal cell co-culture.Reproduction 03/2011; 141(6):809-20. · 3.56 Impact Factor