Agapito Maria A, Zhang Changqing, Murugan Sengottuvelan, Sarkar Dipak K
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.
Endocrinology. 2014 Jul;155(7):2578-88. doi: 10.1210/en.2013-2030. Epub 2014 May 5.
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.
早期乙醇喂养（ELAF）会改变促阿片-黑素细胞皮质素（POMC）生成神经元的代谢功能以及下丘脑时钟调节基因的昼夜节律表达。我们研究了昼夜节律机制是否控制ELAF对POMC神经元中代谢信号基因的作用。对POMC增强型绿色荧光蛋白小鼠下丘脑激光捕获显微切割的POMC神经元中Pomc以及一组选定的代谢信号基因Stat3、Sirt1、Pgc1-α和Asb4进行基因表达测量，结果显示在光/暗和持续黑暗条件下存在昼夜节律振荡。乙醇对这些神经元进行了编程，使得Pomc、Stat3、Sirt和Asb4基因转录本的成年表达变得无节律。此外，ELAF减弱了POMC神经元中Bmal1、Per1和Per2基因表达的昼夜峰值。我们将Per2突变小鼠与转基因POMC增强型绿色荧光蛋白小鼠杂交，以确定昼夜节律机制在ELAF改变的POMC神经元代谢信号中的作用。我们发现，除了Bmal1基因和Per2突变小鼠中的代谢信号调节基因外，ELAF未能改变大多数昼夜节律基因的无节律表达。比较ELAF对野生型和Per2突变小鼠昼夜血糖的影响发现，ELAF减弱了葡萄糖的昼夜峰值，而Per2突变改变了昼夜周期并阻止了ELAF对葡萄糖峰值的减弱。这些数据表明，Per2基因突变可能通过阻断昼夜节律机制来调节乙醇对下丘脑POMC神经元中Pomc和代谢信号基因的作用。
