title: Muscle Arnt/Hif1β Is Dispensable in Myofiber Type Determination, Vascularization and Insulin Sensitivity.
abstract: Aryl Hydrocarbon Receptor Nuclear Translocator/ hypoxia-inducible factor 1 beta (ARNT/ HIF1β), a member of bHLH-PAS family of transcriptional factors, plays a critical role in metabolic homeostasis, insulin resistance and glucose intolerance. The contributions of ARNT in pancreas, liver and adipose tissue to energy balance through gene regulation have been described. Surprisingly, the impact of ARNT signaling in the skeletal muscles, one of the major organs involved in glucose disposal, has not been investigated, especially in type II diabetes. Here we report that ARNT is expressed in the skeletal muscles, particularly in the energy-efficient oxidative slow-twitch myofibers, which are characterized by increased oxidative capacity, mitochondrial content, vascular supply and insulin sensitivity. However, muscle-specific deletion of ARNT did not change myofiber type distribution, oxidative capacity, mitochondrial content, capillarity, or the expression of genes associated with these features. Consequently, the lack of ARNT in the skeletal muscle did not affect weight gain, lean/fat mass, insulin sensitivity and glucose tolerance in lean mice, nor did it impact insulin resistance and glucose intolerance in high fat diet-induced obesity. Therefore, skeletal muscle ARNT is dispensable for controlling muscle fiber type and metabolic regulation, as well as diet-induced weight control, insulin sensitivity and glucose tolerance.
authors.affiliation: Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, UTHealth, Houston, TX, United States of America.
authors.forename: Pierre-Marie
authors.initials: PM
authors.lastname: Badin
authors.affiliation: Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, UTHealth, Houston, TX, United States of America.
authors.forename: Danesh H
authors.initials: DH
authors.lastname: Sopariwala
authors.affiliation: Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, UTHealth, Houston, TX, United States of America.
authors.forename: Sabina
authors.initials: S
authors.lastname: Lorca
authors.affiliation: Metabolic and Degenerative Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, UTHealth, Houston, TX, United States of America.|Integrative Biology and Pharmacology, McGovern Medical School, UTHealth, Houston, TX, United States of America.|Graduate School of Biomedical Sciences, McGovern Medical School, UTHealth, Houston, TX, United States of America.
authors.forename: Vihang A
authors.identifier: http://orcid.org/0000-0001-5574-083X
authors.initials: VA
authors.lastname: Narkar
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000502:physiology*; D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000378:metabolism; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology*; D018919:Neovascularization, Physiologic; D015430:Weight Gain
chemical_list: C497397:Arnt protein, mouse; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D005947:Glucose