Brain metabolic sensing and metabolic signaling at the level of an astrocyte

• Published in: Glia Vol. 66; no. 6; pp. 1185 - 1199
• Main Authors: Marina, Nephtali, Turovsky, Egor, Christie, Isabel N, Hosford, Patrick S, Hadjihambi, Anna, Korsak, Alla, Ang, Richard, Mastitskaya, Svetlana, Sheikhbahaei, Shahriar, Theparambil, Shefeeq M, Gourine, Alexander V
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-06-2018; John Wiley and Sons Inc
• Subjects: Animals; Astrocytes; Astrocytes - metabolism; Autonomic nervous system; Brain; Brain - metabolism; brainstem; Breathing; Carbon dioxide; Central nervous system; Change detection; chemoreception; Data processing; Energy balance; Environmental changes; Environmental conditions; Food intake; Ghrelin; Glucagon; gut hormone; Homeostasis; Hormones; Humans; Hypertension; Information processing; Leptin; Metabolism; Neural networks; Neurological diseases; Pathogenesis; Respiration; Rett syndrome; Review; REVIEW ARTICLES; Signaling; Substrates; gut hormone; brainstem; metabolism; chemoreception; breathing; food intake
• ISSN: 0894-1491; 1098-1136
• DOI: 10.1002/glia.23283

Astrocytes support neuronal function by providing essential structural and nutritional support, neurotransmitter trafficking and recycling and may also contribute to brain information processing. In this article we review published results and report new data suggesting that astrocytes function as versatile metabolic sensors of central nervous system (CNS) milieu and play an important role in the maintenance of brain metabolic homeostasis. We discuss anatomical and functional features of astrocytes that allow them to detect and respond to changes in the brain parenchymal levels of metabolic substrates (oxygen and glucose), and metabolic waste products (carbon dioxide). We report data suggesting that astrocytes are also sensitive to circulating endocrine signals—hormones like ghrelin, glucagon‐like peptide‐1 and leptin, that have a major impact on the CNS mechanisms controlling food intake and energy balance. We discuss signaling mechanisms that mediate communication between astrocytes and neurons and consider how these mechanisms are recruited by astrocytes activated in response to various metabolic challenges. We review experimental data suggesting that astrocytes modulate the activities of the respiratory and autonomic neuronal networks that ensure adaptive changes in breathing and sympathetic drive in order to support the physiological and behavioral demands of the organism in ever‐changing environmental conditions. Finally, we discuss evidence suggesting that altered astroglial function may contribute to the pathogenesis of disparate neurological, respiratory and cardiovascular disorders such as Rett syndrome and systemic arterial hypertension.
Main Points
Astrocytes are versatile CNS sensors capable of detecting various metabolic and endocrine signals.
Astrocytes modulate the activities of the brainstem respiratory and autonomic neuronal circuits that ensure metabolic homeostasis.