title: Fetal alcohol exposure disrupts metabolic signaling in hypothalamic proopiomelanocortin neurons via a circadian mechanism in male mice.
abstract: Early-life ethanol feeding (ELAF) alters the metabolic function of proopiomelanocortin (POMC)-producing neurons and the circadian expression of clock regulatory genes in the hypothalamus. We investigated whether the circadian mechanisms control the action of ELAF on metabolic signaling genes in POMC neurons. Gene expression measurements of Pomc and a selected group of metabolic signaling genes, Stat3, Sirt1, Pgc1-α, and Asb4 in laser-captured microdissected POMC neurons in the hypothalamus of POMC-enhanced green fluorescent protein mice showed circadian oscillations under light/dark and constant darkness conditions. Ethanol programmed these neurons such that the adult expression of Pomc, Stat3, Sirt, and Asb4 gene transcripts became arrhythmic. In addition, ELAF dampened the circadian peak of gene expression of Bmal1, Per1, and Per2 in POMC neurons. We crossed Per2 mutant mice with transgenic POMC-enhanced green fluorescent protein mice to determine the role of circadian mechanism in ELAF-altered metabolic signaling in POMC neurons. We found that ELAF failed to alter arrhythmic expression of most circadian genes, with the exception of the Bmal1 gene and metabolic signaling regulating genes in Per2 mutant mice. Comparison of the ELAF effects on the circadian blood glucose in wild-type and Per2 mutant mice revealed that ELAF dampened the circadian peak of glucose, whereas the Per2 mutation shifted the circadian cycle and prevented the ELAF dampening of the glucose peak. These data suggest the possibility that the Per2 gene mutation may regulate the ethanol actions on Pomc and the metabolic signaling genes in POMC neurons in the hypothalamus by blocking circadian mechanisms.
authors.affiliation: Endocrine Program (M.A.A., C.Z., S.M., D.K.S.), Graduate Program in Neuroscience (M.A.A.), Graduate Program in Endocrinology and Animal Biosciences (C.Z.), and Department of Animal Sciences (S.M., D.K.S.), Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Agapito
authors.forename: Changqing
authors.initials: C
authors.lastname: Zhang
authors.forename: Sengottuvelan
authors.initials: S
authors.lastname: Murugan
authors.forename: Dipak K
authors.initials: DK
authors.lastname: Sarkar
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D056926:CLOCK Proteins / Q000235:genetics; D002492:Central Nervous System Depressants / Q000494:pharmacology; D002940:Circadian Rhythm; D000431:Ethanol / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D056950:Period Circadian Proteins / Q000235:genetics; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D011333:Pro-Opiomelanocortin / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D056564:Sirtuin 1 / Q000235:genetics; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics
chemical_list: C530435:Asb4 protein, mouse; D002492:Central Nervous System Depressants; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D050796:STAT3 Transcription Factor; D050826:Suppressor of Cytokine Signaling Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D000431:Ethanol; D011333:Pro-Opiomelanocortin; D056926:CLOCK Proteins; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1