Mus musculus Raw sequence reads. Mus musculus

Despite their opposing actions on food intake, POMC and NPY/AgRP neurons in the arcuate nucleus of the hypothalamus (ARH) are derived from the same progenitors that give rise to ARH neurons. However, the mechanism whereby common neuronal precursors subsequently adopt either the anorexigenic (POMC) or the orexigenic (NPY/AgRP) identity remains elusive.We hypothesize that POMC and NPY/AgRP cell fates are specified and maintained by distinct intrinsic factors. In search of them, we profiled the transcriptomes of developing POMC and NPY/AgRP neurons in E15.5 mice embryos. Moreover, cell-type-specific transcriptomic analyses revealed transcription regulators that are selectively enriched in either population, but whose developmental functions are unknown in these neurons.Among them, we found the expression of the PR domain-containing factor 12 (Prdm12) was enriched in POMC neurons but absent in NPY/AgRP neurons. To study the role of Prdm12 in vivo, we developed and characterized a floxed Prdm12 allele. Selective ablation of Prdm12 in embryonic POMC neurons led to significantly reduced Pomc expression as well as early-onset obesity in mice of either sex that recapitulates symptoms of human POMC deficiency. Interestingly, however, specific deletion of Prdm12 in adult POMC neurons showed that it is no longer required for Pomc expression nor energy balance. Collectively, these findings establish a critical role for Prdm12 in the anorexigenic neuron identity and suggest that it acts developmentally to program body weight homeostasis. Finally, the combination of cell-type-specific genomic and genetic analyses provides a means to dissect cellular and functional diversity in the hypothalamus whose neurodevelopment remains poorly studied.

尽管下丘脑弓状核（arcuate nucleus of the hypothalamus, ARH）内的POMC神经元与NPY/AgRP神经元对食物摄入的调控作用截然相反，但二者均起源于同一群可分化为ARH神经元的神经前体细胞。然而，这类共同的神经前体细胞后续如何分化为厌食性（POMC）或摄食促进性（NPY/AgRP）神经元的具体机制仍有待阐明。我们提出假说：POMC与NPY/AgRP神经元的细胞命运由不同的内在因子决定并维持。为寻找这类因子，我们对小鼠胚胎发育第15.5天（E15.5）的发育中POMC及NPY/AgRP神经元进行了转录组分析。此外，通过细胞类型特异性转录组分析，我们鉴定出了分别在这两类神经元群体中选择性富集的转录调控因子，但这类因子在这些神经元中的发育功能尚未被揭示。在这些候选因子中，我们发现含PR结构域因子12（Prdm12）的表达在POMC神经元中显著富集，而在NPY/AgRP神经元中几乎无表达。为在活体水平研究Prdm12的功能，我们构建并验证了floxed型Prdm12等位基因。在胚胎期POMC神经元中特异性敲除Prdm12，会导致雌雄小鼠均出现Pomc表达水平显著降低，并伴随早发性肥胖，该表型重现了人类POMC缺乏症的相关症状。有趣的是，在成年POMC神经元中特异性敲除Prdm12则未观察到Pomc表达异常或能量平衡紊乱。综上，这些研究结果证实了Prdm12在维持厌食性神经元身份中的关键作用，并表明其在发育阶段参与调控体重稳态的建立。最后，细胞类型特异性基因组与遗传分析的结合，为解析神经发育研究仍较为匮乏的下丘脑区域的细胞与功能多样性提供了新的研究思路。