Circadian Dysfunction in Adipose Tissue: Chronotherapy in Metabolic Diseases

SIMPLE SUMMARY: The circadian timing system is our bodies’ built-in clock and controls our physiology on a daily basis. This system helps us adapt to changes in our environment, such as light and dark cycles, temperature changes, and the timing of meals. Disruptions to this system are linked to many health problems, including cancer, sleep disorders, and metabolic disorders such as diabetes and obesity. One key player in this system is adipose tissue, or fat, which stores and releases energy. Changes in how this tissue works can significantly impact our metabolic health. This article explores how the circadian timing system and adipose tissue interact and how disruptions to this interaction can lead to metabolic diseases. Furthermore, the potential of chronotherapy, a new field that uses our understanding of the circadian timing system to improve treatments for metabolic disorders, is discussed. This approach includes the timing of medication and targeting specific genes that regulate our natural clock. By understanding these complex interactions, it could be possible to develop more effective treatments for metabolic disorders such as obesity and diabetes. ABSTRACT: Essential for survival and reproduction, the circadian timing system (CTS) regulates adaptation to cyclical changes such as the light/dark cycle, temperature change, and food availability. The regulation of energy homeostasis possesses rhythmic properties that correspond to constantly fluctuating needs for energy production and consumption. Adipose tissue is mainly responsible for energy storage and, thus, operates as one of the principal components of energy homeostasis regulation. In accordance with its roles in energy homeostasis, alterations in adipose tissue’s physiological processes are associated with numerous pathologies, such as obesity and type 2 diabetes. These alterations also include changes in circadian rhythm. In the current review, we aim to summarize the current knowledge regarding the circadian rhythmicity of adipogenesis, lipolysis, adipokine secretion, browning, and non-shivering thermogenesis in adipose tissue and to evaluate possible links between those alterations and metabolic diseases. Based on this evaluation, potential therapeutic approaches, as well as clock genes as potential therapeutic targets, are also discussed in the context of chronotherapy.