Leptin directly controls proliferation, apoptosis and secretory activity of cultured chicken ovarian cells

Sirotkin, Alexander V.; Großmann, Roland

doi:10.1016/j.cbpa.2007.06.001

Cited by 60 publications

(53 citation statements)

References 39 publications

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“…Reports on the expression of this chicken leptin gene at the mRNA and protein levels were also published (Ashwell et al 1999a,b, 2001, Richards et al 1999, Dridi et al 2000b, 2005a, Kochan et al 2006, Hu et al 2008, Rao et al 2009). This and other leptins were reported to attenuate appetite, fat metabolism, reproduction, and immune response following their application to birds (Denbow et al 2000, Dridi et al 2000a, 2005a,b, 2007, Benomar et al 2003, Lohmus et al 2003, Paczoska-Eliasiewicz et al 2003, Cassy et al 2004, Kuo et al 2005, Figueiredo et al 2007, Yang & Denbow 2007, and to affect proliferation, apoptosis, and secretory activity in cultured chicken ovarian cells (Sirotkin & Grossmann 2007) and CLEPR expression in cultured chicken hepatoma cells . In contrast, immunization against leptin decreased appetite and egg-laying ); moreover, other reports showed no effect of exogenous leptin by i.c.v.…”

Section: Discussionmentioning

confidence: 88%

Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Yosefi

Hen²,

Rosenblum³

et al. 2010

Journal of Endocrinology

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Unsuccessful attempts to identify the leptin gene in birds are well documented, despite the characterization of its receptor (LEPR). Since leptin and LEPR have poor sequence conservation among vertebrates, we speculated that a functional assay should represent the best way to detect leptin in birds. Using a leptin bioassay that is based on activation of the chicken LEPR in cultured cells, blood samples from wild birds with extreme seasonal variation in voluntary food intake and fat deposition (Adélie penguins and bar-tailed godwits) were tested for leptin activity. In these experiments, blood samples collected during the pre-incubation and the chick-rearing periods of Adélie penguins, and during the migratory flight and refueling stages of bar-tailed godwits, were found to contain no detectable leptin activity, while the sensitivity of the assay to activation by human blood samples from donor subjects representing a variety of body mass indices and fat contents was clearly demonstrated. These results suggest that in birds, an alternative control mechanism to that of mammals operates in the communication between the body fat tissues and the central control on energy homeostasis.

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Section: Discussionmentioning

confidence: 88%

Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Yosefi

Hen²,

Rosenblum³

et al. 2010

Journal of Endocrinology

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“…Moreover, other adipokines, such as adiponectin and leptin, were able to modulate basal or hormone-induced proliferation of GCs from different species (Spicer et al 2000, Sirotkin & Grossmann 2007, Sirotkin et al 2008, Maillard et al 2010, Sirotkin & Meszarosova 2010. For these reasons, we evaluated the potential effects of several doses of recombinant resistinGIGF1 (76 ng/ml) on the proliferation of primary bovine and rat GCs for 24 h. As already shown for adiponectin (Chabrolle et al 2007b) and leptin (Duggal et al 2002) on rat GC proliferation, no effect of rr resistin (10 and 100 ng/ml) was observed on basal and IGF1-induced mitosis of rat GCs in our study, suggesting that adipokines including resistin do not play a role in rat GC growth.…”

Section: Role Of Resistin In Granulosa Cellsmentioning

confidence: 99%

Expression and effect of resistin on bovine and rat granulosa cell steroidogenesis and proliferation

Maillard¹,

Froment²,

Ramé³

et al. 2011

Reproduction

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Resistin, initially identified in adipose tissue and macrophages, was implicated in insulin resistance. Recently, its mRNA was found in hypothalamo-pituitary axis and rat testis, leading us to hypothesize that resistin may be expressed in ovary. In this study, we determined in rats and cows 1) the characterization of resistin in ovary by RT-PCR, immunoblotting, and immunohistochemistry and 2) the effects of recombinant resistin (10, 100, 333, and 667 ng/ml)GIGF1 (76 ng/ml) on steroidogenesis, proliferation, and signaling pathways of granulosa cells (GC) measured by enzyme immunoassay, [3 H]thymidine incorporation, and immunoblotting respectively. We observed that resistin mRNA and protein were present in several bovine and rat ovarian cells. Nevertheless, only bovine GC abundantly expressed resistin mRNA and protein. Resistin treatment decreased basal but not IGF1-induced progesterone (P!0.05; whatever the dose) and estradiol (P!0.005; for 10 and 333 ng/ml) production by bovine GC. In rats, resistin (10 ng/ml) increased basal and IGF1-induced progesterone secretion (P!0.0001), without effect on estradiol release. We found no effect of resistin on rat GC proliferation. Conversely, in cows, resistin increased basal proliferation (P!0.0001; for 100-667 ng/ml) and decreased IGF1-induced proliferation of GC (P!0.0001; for 10-333 ng/ml) associated with a decrease in cyclin D2 protein level (P!0.0001). Finally, resistin stimulated AKT and p38-MAPK phosphorylation in both species, ERK1/2-MAPK phosphorylation in rats and had the opposite effect on the AMPK pathway (P!0.05). In conclusion, our results show that resistin is expressed in rat and bovine ovaries. Furthermore, it can modulate GC functions in basal state or in response to IGF1 in vitro.

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“…The presence of transfection reagent labeled with tetramethylrhodamine (Jet-SI-Endo-FluoR) and cyclin B1 in cells was detected by fluorescence microscopy. The specificity of the primary antibodies used here and the molecular weight of their ligands were confirmed by western blotting as described , Sirotkin & Grossmann 2006, 2007b.…”

Section: Immunocytochemical Analysismentioning

confidence: 99%

Identification of protein kinases that control ovarian hormone release by selective siRNAs

Sirotkin¹,

Ovcharenko²,

Mlyncek³

2009

Journal of Molecular Endocrinology

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The goal of this study was to identify protein kinases (PKs) that control the secretory activity of human ovarian cells. Cultured ovarian granulosa cells were transfected with 264 siRNA constructs that selectively block the expression of 88 known PKs. The efficiency of transfection and of silencing marker molecules (glyceraldehyde 3-phosphate dehydrogenase, GAPDH and CDC2/p34 PK) was validated by fluorescence microscopy, real-time reverse transcription-PCR, and immunocytochemistry. Release of steroid hormones (progesterone, P 4 ) and IGF1 was determined by RIA. siRNA suppressed the expression of marker molecules by up to 84%. P 4 release was suppressed after inhibiting 34 individual PKs and was stimulated after inhibiting 12 PKs. Blocking nine individual PKs inhibited IGF1 release, while the inactivation of 17 others stimulated IGF1 release. Together, these results demonstrate that the release of both steroid and peptide hormones by human ovarian cells is controlled by a large number of PKs, and that siRNA constructs may be useful tools for further defining the role of PKs in controlling ovarian secretory function.

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Leptin directly controls proliferation, apoptosis and secretory activity of cultured chicken ovarian cells

Cited by 60 publications

References 39 publications

Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Expression and effect of resistin on bovine and rat granulosa cell steroidogenesis and proliferation

Identification of protein kinases that control ovarian hormone release by selective siRNAs

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