Identification of puberty related miRNAs in the hypothalamus of female mice

Puberty is the crucial developmental stage of transition from childhood to adulthood, organized by complex hormonal signaling within the neuroendocrine system with the hypothalamus regulating functions through the hypothalamic-pituitary-gonadal axis. Genetic predisposition and environmental factors influence the pubertal timing, while miRNAs appear as potential regulators by either repressing genes or activating them by inhibiting their repressors. We investigated miRNAs involvement in puberty control, by comparing the total population of miRNAs in the hypothalamus of female mice before, during and after puberty, through RNA sequencing. Our results present up- or down-regulation of expression on several miRNAs from pre-pubertal to pubertal stage. Monitoring these levels post-pubertally revealed four expression patterns, in which pathway analysis displayed associations with developmental processes, cell cycle regulation, metabolic biosynthesis and epigenetic regulation. These findings improve our understanding of the molecular pathways underlying puberty and stress the significance of miRNAs in fine-tuning gene expression within the hypothalamus. RNA-seq of the whole miRNAs population in the hypothalamus of female C57BL/6 mice at three age groups, before puberty (postnatal day 14), during puberty (postnatal day 35) and after puberty (postnatal day 56).青春期是从童年向成年过渡的关键发育阶段，该过程由神经内分泌系统内复杂的激素信号通路调控，下丘脑通过下丘脑-垂体-性腺轴（hypothalamic-pituitary-gonadal axis）实现功能调节。遗传易感性与环境因素均可影响青春期启动时间，而微小RNA（miRNAs）作为潜在调控因子，可通过抑制基因表达或通过抑制其阻遏物来激活基因。本研究通过RNA测序（RNA-seq）技术，对比雌性小鼠下丘脑内全部微小RNA群体在青春期前、青春期及青春期后的表达差异，以此探究微小RNA在青春期调控中的作用。研究结果显示，从青春期前到青春期阶段，多种微小RNA的表达出现上调或下调。对青春期后这些微小RNA的表达水平进行监测后，共发现四种表达模式；通路分析结果显示，这些模式与发育过程、细胞周期调控、代谢生物合成以及表观遗传调控（epigenetic regulation）密切相关。上述发现加深了我们对青春期背后分子通路的理解，并强调了微小RNA在下丘脑内精准调控基因表达的重要意义。本研究的测序对象为三个年龄组的雌性C57BL/6小鼠下丘脑内的全部微小RNA群体，三个年龄组分别为：青春期前（出生后第14天）、青春期（出生后第35天）以及青春期后（出生后第56天）。