Environmental factors act through aryl hydrocarbon receptor activation and circadian rhythm disruption to regulate energy metabolism

Abstract

Environmental factors act through aryl hydrocarbon receptor activation and circadian rhythm disruption to regulate energy metabolism Ali Q Khazaal,1,2 Cassie D Jaeger,3 Kathleen M Bottum,4 Shelley A Tischkau1,3 1Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA; 2Biotechnology Department, College of Science, Baghdad University, Baghdad, Iraq; 3Department of Pharmacology, Southern Illinois University School of Medicine, 4Department of Internal Medicine, Division of Medicine and Psychiatry, Southern Illinois University School of Medicine, Springfield, IL, USA Abstract: Disruption of energy metabolism, resulting in metabolic illnesses including diabetes, hyperlipidemia, fatty liver, hypertension and atherosclerosis, will likely shorten human life expectancy over the next several decades. Past work focusing on diet and exercise needs to be continued, but new environmental factors such as exposure to pollutants and the disruption of circadian rhythms in modern life urgently need more attention and understanding. This review focuses on how environmental pollutants acting through the aryl hydrocarbon receptor (AhR) to cause circadian disruption lead to metabolic derangements. AhR-mediated metabolic dysregulation in the whole organism, and dysregulation specific to the liver and adipose tissue, will be explored. Finally, the role of AhR in circadian desynchrony and resultant effects on energy metabolism will be discussed. This review summarizes information vital to future developments that can combat metabolic illnesses. Keywords: aryl hydrocarbon receptor, adipogenesis, glucose metabolism, lipolysis, circadian rhythm, insulin sensitivity