Wnt/β-catenin和NF-κB信号串扰在褪黑激素核受体介导单色光影响鸡淋巴细胞增殖中的作用

Melatonin is a critical signaling for rapport between environmental light information and cellular response to the body, and its characteristic contains both membrane receptor and nuclear receptor. Our previous studies have shown that monochromatic green light stimulated melatonin secretion to induce lymphocyte proliferation and to promote immune function in the chicks via melatonin membrane receptor pathway. However, the melatonin nuclear receptors are consisted of three subtypes, and play the various functions for controlling call survival, proliferation and differentiation, but how melatonin nuclear receptors mediate the monochromatic light-induced lymphocyte proliferation still remains unclear. Both studies of in vivo and in vitro were used in this study to expose (1) the role of monochromatic light in differential expression of melatonin nuclear receptor in various immune organs, (2) whether effect of melatonin nuclear receptor on the monochromatic light-induced lymphocyte proliferation, (3) mechanisms whereby melatonin nuclear receptor mediates monochromatic light-induced lymphocyte proliferation, and (4) mechanisms underlying how physiological crosstalk between Wnt/β-catenin and NF-κB intracellular signaling pathways on melatonin modulates monochromatic light-induced lymphocyte proliferation. These studies will clarify the hypothesis by which melatonin modulates monochromatic light-induced lymphocyte proliferation in the chickens at the cellular and molecular levels. This study will be helpful to discover the inner relationship between the environment factor (such as light spectra) and the avian functional gene expression, and to provide a new theoretical guidance in improving the avian immune function and helping to deal with the problem of antibiotic abuse by using new light spectra.

褪黑激素是外界光照刺激同体内细胞响应协调关系中的重要信号，特点是同时拥有膜受体和核受体。我们前一结题基金研究发现单色绿光能刺激雏鸡褪黑激素分泌，经膜受体介导淋巴细胞增殖，提高免疫功能。新近发现褪黑激素核受体3个亚型对调控细胞存活、增殖和分化起重要又不同的作用，但褪黑激素核受体在单色光诱导鸡淋巴细胞增殖中的作用机制仍不完全清楚。本课题利用体内与体外试验探究单光色影响鸡不同免疫器官褪黑激素核受体亚型表达的差异，褪黑激素在调控单色光诱导鸡T、B淋巴细胞增殖中核受体是何发挥作用、如何发挥作用（核受体亚型途径）、怎样发挥作用（胞内信号途径和Wnt/β-catenin与NF-κB信号串扰作用）。从细胞与分子水平进一步阐明单色光诱导鸡淋巴细胞增殖的机制：褪黑激素作用假说，有助于揭示环境因子（光色）影响机体功能基因表达的内在联系，为合理利用光色提高家禽免疫力和克服大量使用抗生素的负面影响提供新的突破点。

褪黑激素是外界光照刺激同体内细胞响应协调关系中的重要信号，尤其新近发现褪黑激素核受体3个亚型（RORα、RORβ和RORγ）对调控细胞存活、增殖和分化起重要又不同的作用，但褪黑激素核受体在单色光诱导鸡淋巴细胞增殖中的作用仍不完全清楚。本项目设计利用体内与体外试验探究褪黑激素核受体介导单色光影响鸡淋巴细胞增殖中的作用及其胞内信号转导通路。研究发现：①单色绿光可促进褪黑激素的合成，提高血浆褪黑激素水平。②单色光影响鸡免疫器官褪黑激素核受体表达，绿光通过提高褪黑激素的分泌水平，抑制核受体RORα和RORγ的表达；而红光则相反。③绿光能够诱导鸡淋巴细胞的增殖，与其提高血浆褪黑激素浓度有关。④褪黑激素核受体RORα/RORγ介导单色光对鸡胸腺T淋巴细胞增殖活性的影响；褪黑激素核受体RORα抑制单色光诱导的脾T和B淋巴细胞增殖活性，而核受体RORγ抑制单色光诱导的脾T淋巴细胞增殖活性，但对B淋巴细胞增殖活性没有影响；褪黑激素核受体RORα和RORγ介导绿转蓝光色组合抑制法氏囊B淋巴细胞凋亡的作用。⑤褪黑激素通过核受体RORα/RORγ抑制AKT活性，影响下游GSK3β/β-catenin/CyclinD1信号途径，负反馈调节单色绿光对胸腺T淋巴细胞增殖的促进作用；以及通过RORα/RORγ/NF-κB通路调节B淋巴细胞的发育。这些结果从细胞和分子水平上证明褪黑激素核受体介导单色光影响鸡淋巴细胞增殖的作用机制。研究成果有助于揭示环境因子（光色）影响体内功能基因表达的内在联系规律，有望为合理利用光色信息提高家禽生产力提供新的突破点。