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Neuronal Control of Adaptive Thermogenesis.

Yang X, Ruan HB - Front Endocrinol (Lausanne) (2015)

Bottom Line: The development and activation of "brown-like" adipocytes, also known as beige cells, result in WAT browning and thermogenesis.The recent discovery of brown and beige adipocytes in adult humans has sparked the exploration of the development, regulation, and function of these thermogenic adipocytes.The central nervous system drives the sympathetic nerve activity in BAT and WAT to control heat production and energy homeostasis.

View Article: PubMed Central - PubMed

Affiliation: Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine , New Haven, CT , USA ; Section of Comparative Medicine, Yale University School of Medicine , New Haven, CT , USA ; Department of Cellular and Molecular Physiology, Yale University School of Medicine , New Haven, CT , USA.

ABSTRACT
The obesity epidemic continues rising as a global health challenge, despite the increasing public awareness and the use of lifestyle and medical interventions. The biomedical community is urged to develop new treatments to obesity. Excess energy is stored as fat in white adipose tissue (WAT), dysfunction of which lies at the core of obesity and associated metabolic disorders. By contrast, brown adipose tissue (BAT) burns fat and dissipates chemical energy as heat. The development and activation of "brown-like" adipocytes, also known as beige cells, result in WAT browning and thermogenesis. The recent discovery of brown and beige adipocytes in adult humans has sparked the exploration of the development, regulation, and function of these thermogenic adipocytes. The central nervous system drives the sympathetic nerve activity in BAT and WAT to control heat production and energy homeostasis. This review provides an overview of the integration of thermal, hormonal, and nutritional information on hypothalamic circuits in thermoregulation.

No MeSH data available.


Related in: MedlinePlus

Functional neuroanatomical model of the hypothalamic control of adaptive thermogenesis. Differential regulation of the hypothalamic circuits during fasting and feeding is shown. Positive and negative regulators of the adaptive thermogenesis are shown in green and red, respectively. Dashed lines and gray letters indicate inactive or diminished signals.
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Figure 1: Functional neuroanatomical model of the hypothalamic control of adaptive thermogenesis. Differential regulation of the hypothalamic circuits during fasting and feeding is shown. Positive and negative regulators of the adaptive thermogenesis are shown in green and red, respectively. Dashed lines and gray letters indicate inactive or diminished signals.

Mentions: In addition to their neuroendocrine role, hypothalamic neurons also project to the SNS to control peripheral metabolism (Figure 1). Both BAT and WAT are extensively innervated by the sympathetic fibers that can be tracked back to the hypothalamus (35). By using the neurotropic pseudorabies virus (PRV), a number of studies have described the neuroanatomy of the sympathetic control of adipose tissues in rodents. Although BAT and WAT are anatomically and functionally distinct, common brain areas with efferent projections to both adipose tissues have been identified, including the ARC, LH, and PVN of the hypothalamus and other neuronal sites discussed below (35). Release of catecholamine, particularly norepinephrine (NE), from the sympathetic fibers and subsequent activation of β-AR signaling in adipocytes are necessary for the initiation of lipolysis and the activation of thermogenesis (36). It is thus reasonable to speculate that a “command” neural network dictates these two processes in BAT and WAT (35). It should be noted that only a small portion (about 5–15%) of individual neurons in these common brain regions projects both to BAT and WAT and distinct sympathetic circuits project to different WAT depots (35, 36). It is conceivable that the anatomic architecture of neuronal projections to adipose tissues is evolved to allow differential sympathetic drive across fat depots in response to different lipolytic/thermogenic stimuli (37). Generally speaking, sympathetic drive to BAT is more intense than that to WAT depots, demonstrated by more sympathetic nerve endings on adipocytes, higher NE levels and NE turnover rates, and increased expression levels of tyrosine hydroxylase (37–39). Moreover, there are differential sympathetic activities between various WAT depots at the basal, cold-induced, and fasting-induced conditions (37, 39). It will be interesting to determine what factors control such differential effects of the SNS on adipose tissues.


Neuronal Control of Adaptive Thermogenesis.

Yang X, Ruan HB - Front Endocrinol (Lausanne) (2015)

Functional neuroanatomical model of the hypothalamic control of adaptive thermogenesis. Differential regulation of the hypothalamic circuits during fasting and feeding is shown. Positive and negative regulators of the adaptive thermogenesis are shown in green and red, respectively. Dashed lines and gray letters indicate inactive or diminished signals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585244&req=5

Figure 1: Functional neuroanatomical model of the hypothalamic control of adaptive thermogenesis. Differential regulation of the hypothalamic circuits during fasting and feeding is shown. Positive and negative regulators of the adaptive thermogenesis are shown in green and red, respectively. Dashed lines and gray letters indicate inactive or diminished signals.
Mentions: In addition to their neuroendocrine role, hypothalamic neurons also project to the SNS to control peripheral metabolism (Figure 1). Both BAT and WAT are extensively innervated by the sympathetic fibers that can be tracked back to the hypothalamus (35). By using the neurotropic pseudorabies virus (PRV), a number of studies have described the neuroanatomy of the sympathetic control of adipose tissues in rodents. Although BAT and WAT are anatomically and functionally distinct, common brain areas with efferent projections to both adipose tissues have been identified, including the ARC, LH, and PVN of the hypothalamus and other neuronal sites discussed below (35). Release of catecholamine, particularly norepinephrine (NE), from the sympathetic fibers and subsequent activation of β-AR signaling in adipocytes are necessary for the initiation of lipolysis and the activation of thermogenesis (36). It is thus reasonable to speculate that a “command” neural network dictates these two processes in BAT and WAT (35). It should be noted that only a small portion (about 5–15%) of individual neurons in these common brain regions projects both to BAT and WAT and distinct sympathetic circuits project to different WAT depots (35, 36). It is conceivable that the anatomic architecture of neuronal projections to adipose tissues is evolved to allow differential sympathetic drive across fat depots in response to different lipolytic/thermogenic stimuli (37). Generally speaking, sympathetic drive to BAT is more intense than that to WAT depots, demonstrated by more sympathetic nerve endings on adipocytes, higher NE levels and NE turnover rates, and increased expression levels of tyrosine hydroxylase (37–39). Moreover, there are differential sympathetic activities between various WAT depots at the basal, cold-induced, and fasting-induced conditions (37, 39). It will be interesting to determine what factors control such differential effects of the SNS on adipose tissues.

Bottom Line: The development and activation of "brown-like" adipocytes, also known as beige cells, result in WAT browning and thermogenesis.The recent discovery of brown and beige adipocytes in adult humans has sparked the exploration of the development, regulation, and function of these thermogenic adipocytes.The central nervous system drives the sympathetic nerve activity in BAT and WAT to control heat production and energy homeostasis.

View Article: PubMed Central - PubMed

Affiliation: Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine , New Haven, CT , USA ; Section of Comparative Medicine, Yale University School of Medicine , New Haven, CT , USA ; Department of Cellular and Molecular Physiology, Yale University School of Medicine , New Haven, CT , USA.

ABSTRACT
The obesity epidemic continues rising as a global health challenge, despite the increasing public awareness and the use of lifestyle and medical interventions. The biomedical community is urged to develop new treatments to obesity. Excess energy is stored as fat in white adipose tissue (WAT), dysfunction of which lies at the core of obesity and associated metabolic disorders. By contrast, brown adipose tissue (BAT) burns fat and dissipates chemical energy as heat. The development and activation of "brown-like" adipocytes, also known as beige cells, result in WAT browning and thermogenesis. The recent discovery of brown and beige adipocytes in adult humans has sparked the exploration of the development, regulation, and function of these thermogenic adipocytes. The central nervous system drives the sympathetic nerve activity in BAT and WAT to control heat production and energy homeostasis. This review provides an overview of the integration of thermal, hormonal, and nutritional information on hypothalamic circuits in thermoregulation.

No MeSH data available.


Related in: MedlinePlus