Tanycyte-Independent Control of Hypothalamic Leptin Signaling
Tanycyte-Independent Control of Hypothalamic Leptin Signaling
复制标题
DOI：
10.3389/fnins.2019.00240
复制
发表时间：
2019-03-19
影响因子：
4.3
通讯作者：
Blackshaw, Seth
中科院分区：
文献类型：
--
作者：
Yoo, Sooyeon;Cha, David;Blackshaw, Seth
瘦素由脂肪细胞分泌，用于调节食欲和体重。最近的研究报道，张力细胞主动地将循环中的瘦素通过脑屏障运输到下丘脑，这是正常水平的下丘脑瘦素信号所必需的。然而，缺乏瘦素受体(Lepr)表达的直接证据，也没有研究Tanycell特异性缺失Lepr的效果。在本研究中，我们分析了Tanycell Lepr在小鼠中的表达和功能。用单分子荧光原位杂交(SmfISH)、RT-qPCR、单细胞RNA测序(scRNA-Seq)和选择性缺失LepR，我们无法检测到LepR在Tanycell中的表达。同样，Tanycell特异性的Lepr缺失不会影响Leptin诱导的下丘脑神经元中PSTAT3的表达，无论Leptin是通过腹膜内还是脑室内注射的。最后，我们使用活性调节的scRNA-Seq(ACT-Seq)来全面分析瘦素在下丘脑内侧基底所有细胞类型中诱导的基因表达的变化。瘦素信号的明确证据仅见于内皮细胞和神经元亚群，尽管几乎所有类型的细胞都显示出瘦素诱导的基因表达变化。因此，我们得出结论，Lepr在Tanycell中的表达要么是缺失的，要么是检测不到的低水平，Tanycell不是通过Lepr依赖的机制直接调节下丘脑Leptin信号，Leptin通过直接和间接两种机制调节不同类型下丘脑细胞的基因表达。
Leptin is secreted by adipocytes to regulate appetite and body weight. Recent studies have reported that tanycytes actively transport circulating leptin across the brain barrier into the hypothalamus, and are required for normal levels of hypothalamic leptin signaling. However, direct evidence for leptin receptor (LepR) expression is lacking, and the effect of tanycyte-specific deletion of LepR has not been investigated. In this study, we analyze the expression and function of the tanycytic LepR in mice. Using single-molecule fluorescent in situ hybridization (smfISH), RT-qPCR, single-cell RNA sequencing (scRNA-Seq), and selective deletion of the LepR in tanycytes, we are unable to detect expression of LepR in the tanycytes. Tanycyte-specific deletion of LepR likewise did not affect leptin-induced pSTAT3 expression in hypothalamic neurons, regardless of whether leptin was delivered by intraperitoneal or intracerebroventricular injection. Finally, we use activity-regulated scRNA-Seq (act-Seq) to comprehensively profile leptin-induced changes in gene expression in all cell types in mediobasal hypothalamus. Clear evidence for leptin signaling is only seen in endothelial cells and subsets of neurons, although virtually all cell types show leptin-induced changes in gene expression. We thus conclude that LepR expression in tanycytes is either absent or undetectably low, that tanycytes do not directly regulate hypothalamic leptin signaling through a LepR-dependent mechanism, and that leptin regulates gene expression in diverse hypothalamic cell types through both direct and indirect mechanisms.