Glial Regulation of Energy Metabolism.

The major function of brain glial cells is to maintain a homeostatic milieu for neurons to work properly in response to a variety of environmental alterations. Recent studies have shown that glial cells in the hypothalamus, a brain center controlling homeostatic physiological functions, are essential for regulating energy metabolism in both physiological and pathological conditions. Astrocytes, tanycytes, and NG2-glia shuttle and/or sense key metabolic factors presented to the hypothalamus either directly, by glial metabolic enzymes, receptors, and transporters, or indirectly, by modulating the sensing ability of other types of hypothalamic cells. Astrocytes, tanycytes, and microglia are critically important in the development and maintenance of hypothalamic circuits regulating energy balance. Hypothalamic inflammation commonly associated with diet-induced obesity is manifested via hypothalamic reactive gliosis involving microglia and astrocytes, contributing to the correlated abnormal energy metabolism. Although many glial functions in energy metabolism remain to be fully elucidated, we are at the dawn of targeting glia-neuron interactions in the hypothalamus for therapeutic applications in metabolic disorders.