雌性Wistar-Furth大鼠动情期间垂体前叶内源性neuregulin-1的表达变化(英文)

Endogenous neuregulin-1 expression in the anterior pituitary of female Wistar-Furth rats during the estrous cycle

目的研究雌性Wistar-Furth大鼠发情期不同时段垂体前叶neuregulin-1(Nrg1)的表达变化。方法采用RT-PCR观察雌性Wistar-Furth大鼠不同发情期间垂体Nrg1亚型及其内源受体ErbB-2及ErbB-4mRNA表达变化;应用Western blotting检测蛋白质水平垂体前叶及后叶Nrg1亚型表达变化。采用免疫荧光染色明确表达Nrg1的垂体细胞,并观察垂体前叶Nrg1及磷酸化ErbB-4的分布。此外,研究雄性恒河猴垂体前叶Nrg1及ErbB-4共表达。结果结果显示在大鼠动情周期Ⅰ(E1)和动情周期Ⅱ(E2),部分Nrg1亚型,尤其是Ⅲ型Nrg1mRNA表达水平较高,与E1andE2期垂体前叶Western blotting结果一致。免疫荧光染色表明促性腺激素细胞是垂体前叶Nrg1的主要来源。E1andE2期垂体前叶Nrg1分布广泛,同时伴有ErbB-4受体磷酸化激活。此外,可观察到雄性恒河猴垂体前叶部分Nrg1与ErbB-4毗邻分布。结论雌性Wistar-Furth大鼠垂体前叶有多种Nrg1亚型表达以及Nrg1/ErbB-4信号通路的存在,且与动情周期相关。在雄性非人灵长类垂体前叶存在以Nrg1/ErbB-4为基础的邻分泌机制。

Objective To study the changes in endogenous neuregulin-1 （Nrg1） expression in the anterior pituitary of female Wistar-Furth rats in different phases of the estrous cycle. Methods Female Wistar-Furth rats during estrous cycles were used. RT-PCR was employed to study the changes in the expression of Nrg1 isoforms and their cognate receptors ErbB-2 and ErbB-4 in the anterior pituitary in different phases of the estrous cycle. Western blotting was used to detect Nrg1 expression at the protein level. Immunofluorescence staining was used to identify hypophyseal cells expressing Nrg1 and observe the localization and distribution of Nrg1 and functional phosphorylation of ErbB-4. The co-expression of Nrg1 and ErbB-4 in the anterior pituitary of Rhesus monkey was also investigated. Results Some of the Nrg1 isoforms, especially type III Nrg1s, were expressed at a higher level during the estrous cycle I （E1） and estrous cycle II （E2）, a result consistent with that of Western blotting for samples of the anterior pituitaries collected at these phases. Immunofluorescence staining identified the gonadotrophs as the main source of Nrg1, and showed an extensive distribution of Nrg1 in the anterior pituitary in E1 and E2 phases accompanied by apparent phosphorylated activation of ErbB-4. Adjacent distribution of Nrg1- and ErbB-4-positive cells was also observed in the anterior pituitary of male Rhesus monkeys. Conclusion Our results provide evidence for the expression of multiple Nrg1 isoforms and the presence of Nrg1/ErbB-4 signaling in the anterior pituitary of female Wistar-Furth rats. This signaling demonstrates an estrous cycle phase-related pattern. Additionally, Nrg1/ErbB-4-based juxtacrine signaling may exist in the anterior pituitary of male non-human primate