02634nas a2200289 4500008004100000022001400041245015800055210006900213260001500282300000900297520167800306653001901984653001202003653000902015653000902024653002302033653001202056653002102068100002302089700001802112700003002130700002302160700002002183700002402203700002902227856008802256 2016 eng d a1607-888800aChronic subordination stress selectively downregulates the insulin signaling pathway in liver and skeletal muscle but not in adipose tissue of male mice.0 aChronic subordination stress selectively downregulates the insul c2016 Mar 7 a1-113 aChronic stress has been associated with obesity, glucose intolerance, and insulin resistance. We developed a model of chronic psychosocial stress (CPS) in which subordinate mice are vulnerable to obesity and the metabolic-like syndrome while dominant mice exhibit a healthy metabolic phenotype. Here we tested the hypothesis that the metabolic difference between subordinate and dominant mice is associated with changes in functional pathways relevant for insulin sensitivity, glucose and lipid homeostasis. Male mice were exposed to CPS for four weeks and fed either a standard diet or a high-fat diet (HFD). We first measured, by real-time PCR candidate genes, in the liver, skeletal muscle, and the perigonadal white adipose tissue (pWAT). Subsequently, we used a probabilistic analysis approach to analyze different ways in which signals can be transmitted across the pathways in each tissue. Results showed that subordinate mice displayed a drastic downregulation of the insulin pathway in liver and muscle, indicative of insulin resistance, already on standard diet. Conversely, pWAT showed molecular changes suggestive of facilitated fat deposition in an otherwise insulin-sensitive tissue. The molecular changes in subordinate mice fed a standard diet were greater compared to HFD-fed controls. Finally, dominant mice maintained a substantially normal metabolic and molecular phenotype even when fed a HFD. Overall, our data demonstrate that subordination stress is a potent stimulus for the downregulation of the insulin signaling pathway in liver and muscle and a major risk factor for the development of obesity, insulin resistance, and type 2 diabetes mellitus.10aAdipose tissue10ainsulin10aIRS110aIRS210ametabolic syndrome10aobesity10apathway analysis1 aSanghez, Valentina1 aCubuk, Cankut1 aSebastián-Leon, Patricia1 aCarobbio, Stefania1 aDopazo, Joaquin1 aVidal-Puig, Antonio1 aBartolomucci, Alessandro uhttp://www.tandfonline.com/doi/abs/10.3109/10253890.2016.1151491?journalCode=ists2003446nas a2200277 4500008004100000022001400041245011600055210006900171260001300240300001000253490000600263520251800269100001902787700002102806700002002827700002202847700001802869700001902887700001702906700002202923700002002945700002402965700001902989700002903008856013103037 2016 eng d a2212-877800aStress-induced activation of brown adipose tissue prevents obesity in conditions of low adaptive thermogenesis.0 aStressinduced activation of brown adipose tissue prevents obesit c2016 Jan a19-330 v53 a

BACKGROUND: Stress-associated conditions such as psychoemotional reactivity and depression have been paradoxically linked to either weight gain or weight loss. This bi-directional effect of stress is not understood at the functional level. Here we tested the hypothesis that pre-stress level of adaptive thermogenesis and brown adipose tissue (BAT) functions explain the vulnerability or resilience to stress-induced obesity.

METHODS: We used wt and triple β1,β2,β3-Adrenergic Receptors knockout (β-less) mice exposed to a model of chronic subordination stress (CSS) at either room temperature (22 °C) or murine thermoneutrality (30 °C). A combined behavioral, physiological, molecular, and immunohistochemical analysis was conducted to determine stress-induced modulation of energy balance and BAT structure and function. Immortalized brown adipocytes were used for in vitro assays.

RESULTS: Departing from our initial observation that βARs are dispensable for cold-induced BAT browning, we demonstrated that under physiological conditions promoting low adaptive thermogenesis and BAT activity (e.g. thermoneutrality or genetic deletion of the βARs), exposure to CSS acted as a stimulus for BAT activation and thermogenesis, resulting in resistance to diet-induced obesity despite the presence of hyperphagia. Conversely, in wt mice acclimatized to room temperature, and therefore characterized by sustained BAT function, exposure to CSS increased vulnerability to obesity. Exposure to CSS enhanced the sympathetic innervation of BAT in wt acclimatized to thermoneutrality and in β-less mice. Despite increased sympathetic innervation suggesting adrenergic-mediated browning, norepinephrine did not promote browning in βARs knockout brown adipocytes, which led us to identify an alternative sympathetic/brown adipocytes purinergic pathway in the BAT. This pathway is downregulated under conditions of low adaptive thermogenesis requirements, is induced by stress, and elicits activation of UCP1 in wt and β-less brown adipocytes. Importantly, this purinergic pathway is conserved in human BAT.

CONCLUSION: Our findings demonstrate that thermogenesis and BAT function are determinant of the resilience or vulnerability to stress-induced obesity. Our data support a model in which adrenergic and purinergic pathways exert complementary/synergistic functions in BAT, thus suggesting an alternative to βARs agonists for the activation of human BAT.

1 aRazzoli, Maria1 aFrontini, Andrea1 aGurney, Allison1 aMondini, Eleonora1 aCubuk, Cankut1 aKatz, Liora, S1 aCero, Cheryl1 aBolan, Patrick, J1 aDopazo, Joaquin1 aVidal-Puig, Antonio1 aCinti, Saverio1 aBartolomucci, Alessandro uhttps://www.clinbioinfosspa.es/content/stress-induced-activation-brown-adipose-tissue-prevents-obesity-conditions-low-adaptive