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Loss of cytokine-STAT5 signaling in the CNS and pituitary gland alters energy balance and leads to obesity.

Lee JY, Muenzberg H, Gavrilova O, Reed JA, Berryman D, Villanueva EC, Louis GW, Leinninger GM, Bertuzzi S, Seeley RJ, Robinson GW, Myers MG, Hennighausen L - PLoS ONE (2008)

Bottom Line: STAT5A and STAT5B (STAT5), the most promiscuous members of this family, are highly expressed in specific populations of hypothalamic neurons in regions known to mediate the actions of cytokines in the regulation of energy balance.To test the hypothesis that STAT5 signaling is essential to energy homeostasis, we used Cre-mediated recombination to delete the Stat5 locus in the CNS.These results demonstrate that STAT5 mediates energy homeostasis in response to endogenous cytokines such as GM-CSF.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.

ABSTRACT
Signal transducers and activators of transcription (STATs) are critical components of cytokine signaling pathways. STAT5A and STAT5B (STAT5), the most promiscuous members of this family, are highly expressed in specific populations of hypothalamic neurons in regions known to mediate the actions of cytokines in the regulation of energy balance. To test the hypothesis that STAT5 signaling is essential to energy homeostasis, we used Cre-mediated recombination to delete the Stat5 locus in the CNS. Mutant males and females developed severe obesity with hyperphagia, impaired thermal regulation in response to cold, hyperleptinemia and insulin resistance. Furthermore, central administration of GM-CSF mediated the nuclear accumulation of STAT5 in hypothalamic neurons and reduced food intake in control but not in mutant mice. These results demonstrate that STAT5 mediates energy homeostasis in response to endogenous cytokines such as GM-CSF.

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GM-CSF induces STAT5 activity in the hypothalamus and Stat5fl/fl; Nestin-Cre male mice do not respond to GM-CSF-induced reduction of food intake.(A) Rats were treated with vehicle (left panels) or GM-CSF (right panels) i3vt for 60 minutes and the presence of nuclear STAT5 was analyzed by counting STAT5-positive (green) nuclei of Hu-positive (red) neurons following immunofluorescent analysis with αSTAT5 antibodies. Dapi staining to reveal nuclei is shown in blue. Representative images from the LHA are shown, along with percent of neurons with nuclear STAT5 localization. (B) graph of double labeled cells; n = 4; *p<0.01 vs vehicle by students t test. (C) Recombinant mouse GM-CSF was injected into the third ventricular region of 8 week-old Stat5fl/fl; Nestin-Cre mice and Stat5fl/fl control littermates and food intake was measured after 4 hrs (N = 16 for Stat5 ff vehicle (body weight 29.8±0.9) and Stat5 ff GM-CSF ((body weight 29.4±0.9), n = 6–7 for Stat5 ff; Nestin-Cre (body weight 29.7±1.7) vehicle and Stat5 ff; Nestin-Cre GM-CSF(body weight 29.7±1.8)) . Two-way ANOVA tests followed by the ‘Holm-Sidak test’ revealed significant effect of GM-CSF on food intake (F(1,40) = 4.6, P = 0.039 showed a significant reduction of food intake with control mice and no significant reduction was observed with mutant mice. The p value for the drug effect was 0.039. Using ‘All pairwise multiple comparison procedures’ the p value for drug effect within wild type was 0.008. No significant effect was observed in the mutant group (p 0.435).
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pone-0001639-g009: GM-CSF induces STAT5 activity in the hypothalamus and Stat5fl/fl; Nestin-Cre male mice do not respond to GM-CSF-induced reduction of food intake.(A) Rats were treated with vehicle (left panels) or GM-CSF (right panels) i3vt for 60 minutes and the presence of nuclear STAT5 was analyzed by counting STAT5-positive (green) nuclei of Hu-positive (red) neurons following immunofluorescent analysis with αSTAT5 antibodies. Dapi staining to reveal nuclei is shown in blue. Representative images from the LHA are shown, along with percent of neurons with nuclear STAT5 localization. (B) graph of double labeled cells; n = 4; *p<0.01 vs vehicle by students t test. (C) Recombinant mouse GM-CSF was injected into the third ventricular region of 8 week-old Stat5fl/fl; Nestin-Cre mice and Stat5fl/fl control littermates and food intake was measured after 4 hrs (N = 16 for Stat5 ff vehicle (body weight 29.8±0.9) and Stat5 ff GM-CSF ((body weight 29.4±0.9), n = 6–7 for Stat5 ff; Nestin-Cre (body weight 29.7±1.7) vehicle and Stat5 ff; Nestin-Cre GM-CSF(body weight 29.7±1.8)) . Two-way ANOVA tests followed by the ‘Holm-Sidak test’ revealed significant effect of GM-CSF on food intake (F(1,40) = 4.6, P = 0.039 showed a significant reduction of food intake with control mice and no significant reduction was observed with mutant mice. The p value for the drug effect was 0.039. Using ‘All pairwise multiple comparison procedures’ the p value for drug effect within wild type was 0.008. No significant effect was observed in the mutant group (p 0.435).

Mentions: Central administration of GM-CSF to rats and mice decreases food intake and body weight [8]. Since STAT5 signaling is central to GM-CSF action [9], we hypothesized that diminished GM-CSF action in the CNS may contribute to the obesity of Stat5fl/fl; Nestin-Cre animals. While the antibodies against phosphorylated STAT5 that we tested functioned poorly for immunohistochemistry in brain tissue, immunofluorescent detection of total STAT5 protein was robust and revealed the depletion of diffuse STAT5 staining and the increased intensity of STAT5 nuclear staining in the hypothalamus in response to i3vt GM-CSF injection in rats, consistent with GM-CSF-dependent activation and nuclear accumulation of STAT5 isoforms in the hypothalamus (Figure 9A). Indeed, counting of STAT5-immunoreactive nuclei in confocal images of these stained sections of rat brains revealed that i3vt GM-CSF administration doubled immunohistochemically-detectable STAT5 nuclear accumulation from approximately 20% to 40% of LHA neurons (Figure 9B). Thus, GM-CSF increases STAT5 nuclear accumulation in specific hypothalamic neurons, as in peripheral target tissues [20]. In order to determine a potential role for STAT5 in the anorexigenic actions of GM-CSF, we examined the response of control and Stat5fl/fl; Nestin-Cre mice to i3vt GM-CSF (Figure 9C). While i3vt administration of 1 µg of mouse GM-CSF resulted in a significant reduction of food intake as early as 4 hours in control Stat5fl/fl mice, there was no suppression of food intake in Stat5fl/fl; Nestin-Cre mice (Figure 9C; see description of two-way ANOVA test). In summary, these results suggest that the effects of GM-CSF to suppress food intake require CNS STAT5.


Loss of cytokine-STAT5 signaling in the CNS and pituitary gland alters energy balance and leads to obesity.

Lee JY, Muenzberg H, Gavrilova O, Reed JA, Berryman D, Villanueva EC, Louis GW, Leinninger GM, Bertuzzi S, Seeley RJ, Robinson GW, Myers MG, Hennighausen L - PLoS ONE (2008)

GM-CSF induces STAT5 activity in the hypothalamus and Stat5fl/fl; Nestin-Cre male mice do not respond to GM-CSF-induced reduction of food intake.(A) Rats were treated with vehicle (left panels) or GM-CSF (right panels) i3vt for 60 minutes and the presence of nuclear STAT5 was analyzed by counting STAT5-positive (green) nuclei of Hu-positive (red) neurons following immunofluorescent analysis with αSTAT5 antibodies. Dapi staining to reveal nuclei is shown in blue. Representative images from the LHA are shown, along with percent of neurons with nuclear STAT5 localization. (B) graph of double labeled cells; n = 4; *p<0.01 vs vehicle by students t test. (C) Recombinant mouse GM-CSF was injected into the third ventricular region of 8 week-old Stat5fl/fl; Nestin-Cre mice and Stat5fl/fl control littermates and food intake was measured after 4 hrs (N = 16 for Stat5 ff vehicle (body weight 29.8±0.9) and Stat5 ff GM-CSF ((body weight 29.4±0.9), n = 6–7 for Stat5 ff; Nestin-Cre (body weight 29.7±1.7) vehicle and Stat5 ff; Nestin-Cre GM-CSF(body weight 29.7±1.8)) . Two-way ANOVA tests followed by the ‘Holm-Sidak test’ revealed significant effect of GM-CSF on food intake (F(1,40) = 4.6, P = 0.039 showed a significant reduction of food intake with control mice and no significant reduction was observed with mutant mice. The p value for the drug effect was 0.039. Using ‘All pairwise multiple comparison procedures’ the p value for drug effect within wild type was 0.008. No significant effect was observed in the mutant group (p 0.435).
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Related In: Results  -  Collection

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pone-0001639-g009: GM-CSF induces STAT5 activity in the hypothalamus and Stat5fl/fl; Nestin-Cre male mice do not respond to GM-CSF-induced reduction of food intake.(A) Rats were treated with vehicle (left panels) or GM-CSF (right panels) i3vt for 60 minutes and the presence of nuclear STAT5 was analyzed by counting STAT5-positive (green) nuclei of Hu-positive (red) neurons following immunofluorescent analysis with αSTAT5 antibodies. Dapi staining to reveal nuclei is shown in blue. Representative images from the LHA are shown, along with percent of neurons with nuclear STAT5 localization. (B) graph of double labeled cells; n = 4; *p<0.01 vs vehicle by students t test. (C) Recombinant mouse GM-CSF was injected into the third ventricular region of 8 week-old Stat5fl/fl; Nestin-Cre mice and Stat5fl/fl control littermates and food intake was measured after 4 hrs (N = 16 for Stat5 ff vehicle (body weight 29.8±0.9) and Stat5 ff GM-CSF ((body weight 29.4±0.9), n = 6–7 for Stat5 ff; Nestin-Cre (body weight 29.7±1.7) vehicle and Stat5 ff; Nestin-Cre GM-CSF(body weight 29.7±1.8)) . Two-way ANOVA tests followed by the ‘Holm-Sidak test’ revealed significant effect of GM-CSF on food intake (F(1,40) = 4.6, P = 0.039 showed a significant reduction of food intake with control mice and no significant reduction was observed with mutant mice. The p value for the drug effect was 0.039. Using ‘All pairwise multiple comparison procedures’ the p value for drug effect within wild type was 0.008. No significant effect was observed in the mutant group (p 0.435).
Mentions: Central administration of GM-CSF to rats and mice decreases food intake and body weight [8]. Since STAT5 signaling is central to GM-CSF action [9], we hypothesized that diminished GM-CSF action in the CNS may contribute to the obesity of Stat5fl/fl; Nestin-Cre animals. While the antibodies against phosphorylated STAT5 that we tested functioned poorly for immunohistochemistry in brain tissue, immunofluorescent detection of total STAT5 protein was robust and revealed the depletion of diffuse STAT5 staining and the increased intensity of STAT5 nuclear staining in the hypothalamus in response to i3vt GM-CSF injection in rats, consistent with GM-CSF-dependent activation and nuclear accumulation of STAT5 isoforms in the hypothalamus (Figure 9A). Indeed, counting of STAT5-immunoreactive nuclei in confocal images of these stained sections of rat brains revealed that i3vt GM-CSF administration doubled immunohistochemically-detectable STAT5 nuclear accumulation from approximately 20% to 40% of LHA neurons (Figure 9B). Thus, GM-CSF increases STAT5 nuclear accumulation in specific hypothalamic neurons, as in peripheral target tissues [20]. In order to determine a potential role for STAT5 in the anorexigenic actions of GM-CSF, we examined the response of control and Stat5fl/fl; Nestin-Cre mice to i3vt GM-CSF (Figure 9C). While i3vt administration of 1 µg of mouse GM-CSF resulted in a significant reduction of food intake as early as 4 hours in control Stat5fl/fl mice, there was no suppression of food intake in Stat5fl/fl; Nestin-Cre mice (Figure 9C; see description of two-way ANOVA test). In summary, these results suggest that the effects of GM-CSF to suppress food intake require CNS STAT5.

Bottom Line: STAT5A and STAT5B (STAT5), the most promiscuous members of this family, are highly expressed in specific populations of hypothalamic neurons in regions known to mediate the actions of cytokines in the regulation of energy balance.To test the hypothesis that STAT5 signaling is essential to energy homeostasis, we used Cre-mediated recombination to delete the Stat5 locus in the CNS.These results demonstrate that STAT5 mediates energy homeostasis in response to endogenous cytokines such as GM-CSF.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.

ABSTRACT
Signal transducers and activators of transcription (STATs) are critical components of cytokine signaling pathways. STAT5A and STAT5B (STAT5), the most promiscuous members of this family, are highly expressed in specific populations of hypothalamic neurons in regions known to mediate the actions of cytokines in the regulation of energy balance. To test the hypothesis that STAT5 signaling is essential to energy homeostasis, we used Cre-mediated recombination to delete the Stat5 locus in the CNS. Mutant males and females developed severe obesity with hyperphagia, impaired thermal regulation in response to cold, hyperleptinemia and insulin resistance. Furthermore, central administration of GM-CSF mediated the nuclear accumulation of STAT5 in hypothalamic neurons and reduced food intake in control but not in mutant mice. These results demonstrate that STAT5 mediates energy homeostasis in response to endogenous cytokines such as GM-CSF.

Show MeSH
Related in: MedlinePlus