Metabolic signalling to somatotrophs: Transcriptional and post-transcriptional mediators.
Metabolic signalling to somatotrophs: Transcriptional and post-transcriptional mediators.
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DOI：
10.1111/jne.12883
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发表时间：
2020-11
影响因子：
3.2
通讯作者：
Childs GV
中科院分区：
文献类型：
--
作者：
Allensworth-James ML;Odle AK;Lim J;LaGasse AN;Miles TK;Hardy LL;Haney AC;MacNicol MC;MacNicol AM;Childs GV
在正常人中，垂体生长激素细胞通过响应瘦素的代谢信号来优化身体组成。为了确定瘦素调节生长激素的机制，我们使用Cre-LoxP技术选择性地删除生长激素中的瘦素受体（LEPR），并开发了通过荧光激活细胞分选（FACS）纯化的含有99%生长激素的群体。流式细胞仪纯化，麻风病无效的生长激素细胞显示生长激素（GH），生长激素释放激素受体（GHRHR），和Pou 1f 1蛋白和Gh（女性）和Ghrhr（两种性别）的mRNA水平降低。纯生长激素细胞也表达促甲状腺激素（TSH）和催乳素（PRL），这两种激素在缺乏LEPR的纯生长激素细胞中均减少。这引入了五种作为瘦素靶点的基因产物。在本研究中，我们测试的假设，瘦素是一个转录和转录后调节这些基因产物。我们的测试表明，Pou 1f 1和/或Janus激酶/信号转导子和转录激活子3转录调节途径参与Gh或Ghrhr mRNA的瘦素调节。然后，我们专注于候选microRNAs（miRNAs）与Gh或Ghrhr mRNA的3' UTR上的共有结合位点的潜在作用。生长激素型Lepr缺失突变体表达水平升高的miRNA，包括miR 1197 - 3 p（雌性），miR 103 - 3 p和miR 590 - 3 p（两性），其结合Gh mRNA，或miRNA-325- 3 p（两性均升高），其结合Ghrhr mRNA。这种升高表明在不存在LEPR的情况下翻译受到抑制。此外，在检测Musashi在Tshb和Prl 3' UTR上的结合位点后，我们确定Musashi 1在体外fluc测定中抑制两种mRNA的翻译，并且在Musashi免疫沉淀测定中富集Prl mRNA。最后，我们测试了生长激素释放肽的行动，以确定其一氧化氮介导的信号通路是否会恢复缺失突变体的促生长素功能。Ghrelin在体外不能恢复GHRH结合或GH分泌。这些研究显示了一个意想不到的广泛的作用，瘦素在维持生长激素功能，包括调节PRL和促甲状腺激素的亚群的生长激素细胞，可能是祖细胞。
In normal individuals, pituitary somatotrophs optimise body composition by responding to metabolic signals from leptin. To identify mechanisms behind the regulation of somatotrophs by leptin, we used Cre-LoxP technology to delete leptin receptors (LEPR) selectively in somatotrophs and developed populations purified by fluorescence-activated cell sorting (FACS) that contained 99% somatotrophs. FACS-purified, Lepr-null somatotrophs showed reduced levels of growth hormone (GH), growth hormone-releasing hormone receptor (GHRHR), and Pou1f1 proteins and Gh (females) and Ghrhr (both sexes) mRNAs. Pure somatotrophs also expressed thyroid-stimulating hormone (TSH) and prolactin (PRL), both of which were reduced in pure somatotrophs lacking LEPR. This introduced five gene products that were targets of leptin. In the present study, we tested the hypothesis that leptin is both a transcriptional and a post-transcriptional regulator of these gene products. Our tests showed that Pou1f1 and/or the Janus kinase/signal transducer and activator of transcription 3 transcriptional regulatory pathways are implicated in the leptin regulation of Gh or Ghrhr mRNAs. We then focused on potential actions by candidate microRNAs (miRNAs) with consensus binding sites on the 3’ UTR of Gh or Ghrhr mRNAs. Somatotroph Lepr-null deletion mutants expressed elevated levels of miRNAs including miR1197-3p (in females), miR103-3p and miR590-3p (both sexes), which bind Gh mRNA, or miRNA-325-3p (elevated in both sexes), which binds Ghrhr mRNA. This elevation indicates repression of translation in the absence of LEPR. In addition, after detecting binding sites for Musashi on Tshb and Prl 3’ UTR, we determined that Musashi1 repressed translation of both mRNAs in in vitro fluc assays and that Prl mRNA was enriched in Musashi immunoprecipitation assays. Finally, we tested ghrelin actions to determine whether its nitric oxide-mediated signalling pathways would restore somatotroph functions in deletion mutants. Ghrelin did not restore either GHRH binding or GH secretion in vitro. These studies show an unexpectedly broad role for leptin with respect to maintaining somatotroph functions, including the regulation of PRL and TSH in subsets of somatotrophs that may be progenitor cells.
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DOI：
10.1073/pnas.93.13.6231
发表时间：
1996-06-25
影响因子：
11.1
作者：
Ghilardi, N;Ziegler, S;Skoda, RC
通讯作者：
Skoda, RC
影响因子：
4.8
作者：
Cheung, Leonard Y. M.;George, Akima S.;Camper, Sally A.
通讯作者：
Camper, Sally A.
影响因子：
4.8
作者：
Arumugam, Karthik;MacNicol, Melanie C.;MacNicol, Angus M.
通讯作者：
MacNicol, Angus M.
影响因子：
5.3
作者：
Imai, T;Tokunaga, A;Okano, H
通讯作者：
Okano, H
影响因子：
--
作者：
Asada, N;Takahashi, Y;Honjo, M
通讯作者：
Honjo, M