Regulation of adipocyte thermogenesis: mechanisms controlling obesity

Abstract

Adipocyte biology has been intensely researched in recent years due to the emergence of obesity as a serious global health concern and because of the realization that adipose tissue is more than simply a cell type that stores and releases lipids. The plasticity of adipose tissues, to rapidly adapt to altered physiological states of energy demand, is under neuronal and endocrine control. The capacity for white adipocytes to store chemical energy in lipid droplets is key for protecting other organs from the toxic effects of ectopic lipid deposition. In contrast, thermogenic (brown and beige) adipocytes combust macronutrients to generate heat. The thermogenic activity of adipocytes allows them to protect themselves and other tissues from lipid overaccumulation. Advances in brown fat biology have uncovered key molecular players involved in adipocyte determination, differentiation, and thermogenic activation. It is now, well appreciated that three distinct adipocyte types exist: white, beige, and brown. Moreover, functional differences are present within adipocyte subtypes located in anatomically distinct locations. Adding to this complexity is the recent realization from singlecell sequencing studies that adipocyte progenitors are also heterogeneous. Understanding the molecular details of how to increase the number of thermogenic fat cells and their activation may delineate some of the pathophysiological basis of obesity and obesity-related diseases. Here, we review recent advances that have extended our understanding of the central role that adipose tissue plays in energy balance and the mechanisms that control their amount and function.

Control of Adipose Cell Browning and Its Therapeutic Potential

“…This type of adipose tissue is observed in circumstances of low temperatures or after sympathetic activation [ 10 ]. Although this adipose tissue is functionally very similar to BAT, it has specific characteristics and for this reason it has been referred to as beige adipose tissue [ 11 , 12 ]. Although adipose tissue has a mesenchymal origin, in the differentiation process manifest differences are established and BAT has more similarities with muscle cells of mesenchymal origin than with WAT [ 13 , 14 ].…”

Adipose ABHD6 regulates tolerance to cold and thermogenic programs

“…The contribution of this thermogenic mechanism was revealed by the suppression of adipose ABHD6, which negatively regulates 2-MAG levels. As any other physiological functions, cold-induced thermogenesis is tightly regulated with both positive and negative modulators (55). Our data demonstrate that adipocyte ABHD6 acts as a brake for thermogenesis in the visceral fat to fine-tune coldinduced heat production and to prevent the loss of adipocyte lipid stores.…”

High prevalence for obesity in severe COVID-19: Possible links and perspectives towards patient stratification

“…By contrast, brown adipose tissue (BAT) as well as the beige adipocytes dissipates energy in the form of heat by uncoupling mitochondrial respiratory chain from ATP synthesis. The presence of brown/beige adipose tissue is associated with metabolic health and the amount of brown/beige adipocytes is reduced in obesity and with aging [63,64]. The expression of inflammatory markers is lower in brown than in white adipose tissues, providing further support that brown adipose tissue is generally more resistant to inflammation.…”