title: Separate and shared sympathetic outflow to white and brown fat coordinately regulates thermoregulation and beige adipocyte recruitment.
abstract: White adipose tissue (WAT) and brown adipose tissue (BAT) are innervated and regulated by the sympathetic nervous system (SNS). It is not clear, however, whether there are shared or separate central SNS outflows to WAT and BAT that regulate their function. We injected two isogenic strains of pseudorabies virus, a retrograde transneuronal viral tract tracer, with unique fluorescent reporters into interscapular BAT (IBAT) and inguinal WAT (IWAT) of the same Siberian hamsters to define SNS pathways to both. To test the functional importance of SNS coordinated control of BAT and WAT, we exposed hamsters with denervated SNS nerves to IBAT to 4°C for 16-24 h and measured core and fat temperatures and norepinephrine turnover (NETO) and uncoupling protein 1 (UCP1) expression in fat tissues. Overall, there were more SNS neurons innervating IBAT than IWAT across the neuroaxis. However, there was a greater percentage of singly labeled IWAT neurons in midbrain reticular nuclei than singly labeled IBAT neurons. The hindbrain had ~30-40% of doubly labeled neurons while the forebrain had ~25% suggesting shared SNS circuitry to BAT and WAT across the brain. The raphe nucleus, a key region in thermoregulation, had ~40% doubly labeled neurons. Hamsters with IBAT SNS denervation maintained core body temperature during acute cold challenge and had increased beige adipocyte formation in IWAT. They also had increased IWAT NETO, temperature, and UCP1 expression compared with intact hamsters. These data provide strong neuroanatomical and functional evidence of WAT and BAT SNS cross talk for thermoregulation and beige adipocyte formation.
authors.affiliation: Department of Biology, Georgia State University, Atlanta, Georgia.|Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and.
authors.forename: Ngoc Ly T
authors.initials: NL
authors.lastname: Nguyen
authors.affiliation: Neuroscience Institute, Georgia State University, Atlanta, Georgia.
authors.forename: Candace L
authors.initials: CL
authors.lastname: Barr
authors.affiliation: Department of Biology, Georgia State University, Atlanta, Georgia.|Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and.
authors.forename: Vitaly
authors.initials: V
authors.lastname: Ryu
authors.affiliation: Department of Biology, Georgia State University, Atlanta, Georgia.|Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cao
authors.affiliation: Department of Biology, Georgia State University, Atlanta, Georgia; bxue@gsu.edu.|Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and.|Neuroscience Institute, Georgia State University, Atlanta, Georgia.
authors.forename: Bingzhong
authors.initials: B
authors.lastname: Xue
authors.affiliation: Department of Biology, Georgia State University, Atlanta, Georgia.|Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and.|Neuroscience Institute, Georgia State University, Atlanta, Georgia.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Bartness
mesh_terms: D017667:Adipocytes / Q000502:physiology*; D000069797:Adipocytes, Beige / Q000166:cytology / Q000502:physiology*; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000294:innervation / Q000502:physiology*; D052436:Adipose Tissue, White / Q000166:cytology / Q000294:innervation / Q000502:physiology*; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D006224:Cricetinae; D025461:Feedback, Physiological / Q000502:physiology; D008297:Male; D017111:Phodopus; D013564:Sympathetic Nervous System / Q000502:physiology*; D000071436:Thermotolerance / Q000502:physiology
keywords: cold exposure; denervation; norepinephrine turnover; pseudorabies virus