Abstract：
Growth hormone-releasing hormone (Ghrh) neurons in the dorsomedial ventromedial hypothalamic nucleus (VMNdm) express the metabolic transcription factor steroidogenic factor-1 and hypoglycemia-sensitive neurochemicals of diverse chemical structures, transmission modes, and temporal signaling profiles. Ghrh imposes neuromodulatory control of coexpressed transmitters. Multiple metabolic sensory mechanisms are employed in the brain, including screening of the critical nutrient glucose or the energy currency ATP. Here, combinatory laser-catapult-microdissection/single-cell multiplex qPCR tools were used to investigate whether these neurons possess molecular machinery for monitoring cellular metabolic status and if these biomarkers exhibit sex-specific sensitivity to insulin-induced hypoglycemia. Data show that hypoglycemia up- (male) or downregulated (female) Ghrh neuron glucokinase (Gck) mRNA; Ghrh gene silencing decreased baseline and hypoglycemic patterns of Gck gene expression in each sex. Ghrh neuron glucokinase regulatory protein (Gckr) transcript levels were respectively diminished or augmented in hypoglycemic male vs female rats; this mRNA profile was decreased by Ghrh siRNA in both sexes. Gene transcripts encoding catalytic alpha subunits of the energy monitor 5-AMP-activated protein kinase (AMPK), i.e., Prkaa1 and 2, were increased by hypoglycemia in males, yet only the former mRNA was hypoglycemia-sensitive in females. Ghrh siRNA downregulated baseline and hypoglycemia-associated Prkaa subunit mRNAs in males but elicited divergent changes in Prkaa2 transcripts in eu- vs hypoglycemic females. Results provide unique evidence that VMNdm Ghrh neurons express the characterized metabolic sensor biomarkers glucokinase and AMPK and that the corresponding gene profiles exhibit distinctive sex-dimorphic transcriptional responses to hypoglycemia. Data further document Ghrh neuromodulation of baseline and hypoglycemic transcription patterns of these metabolic gene profiles.
摘要：
下丘脑腹内侧核（VMNdm）中的生长激素释放激素（Ghrh）神经元表达代谢转录因子类固醇生成因子-1和不同化学结构的低血糖敏感神经化学物质，传输模式,和时间信号分布。Ghrh对共表达的递质进行神经调节控制。大脑中采用了多种代谢感觉机制，包括筛选关键营养素葡萄糖或能量货币ATP。这里,组合激光-弹射器-显微切割/单细胞多重qPCR工具用于研究这些神经元是否具有监测细胞代谢状态的分子机制,以及这些生物标志物是否对胰岛素诱导的低血糖表现出性别特异性敏感性.数据显示,低血糖上调(男性)或下调(女性)Ghrh神经元葡糖激酶(Gck)mRNA;Ghrh基因沉默降低基线和低血糖模式中每个性别的Gck基因表达。在低血糖的雄性大鼠和雌性大鼠中，Ghrh神经元葡萄糖激酶调节蛋白（Gckr）转录水平分别降低或增加；两性的GhrhsiRNA降低了该mRNA谱。编码能量监测器5-AMP激活蛋白激酶（AMPK）的催化α亚基的基因转录本，即，Prkaa1和2因男性低血糖而增加，然而在女性中,只有前一种mRNA对低血糖敏感.GhrhsiRNA在男性中下调基线和低血糖相关的Prkaa亚基mRNA，但在eu-与低血糖女性中引起Prkaa2转录本的不同变化。结果提供了独特的证据，表明VMNdmGhrh神经元表达表征的代谢传感器生物标志物葡萄糖激酶和AMPK，并且相应的基因谱表现出对低血糖的独特的性别二态转录反应。数据进一步记录了这些代谢基因谱的基线和低血糖转录模式的Ghrh神经调节。
