功能性TSHβ剪接变体生物学特性及其与桥本甲状腺炎发病相关性研究

The first immune-derived functional splice variant of TSHβ was identified by Vincent et al in 2009. In addition, in C57BL/6 mice infected with the T3D reovirus, the mRNA expression of the TSHβ splice variant was upregulated seven times in the thyroid. In our previous experiments, the TSHβ splice variant gene, but not the native form of TSHβ, was expressed in the normal thyroid tissue and abnormal thyroid tissue from patients with Hashimoto's thyroiditis (HT) , furthermore, mRNA expressions of TSHβ splice variant were higher in peripheral blood leukocytes (PBL) of HT patients compared with the control group. The results above demonstrated that TSHβ splice variant may play a vital role in the pathogenesis of HT. To date, it is not elucidated in details that the important biological characteristics of TSHβ splice variant and whether TSHβ splice variant takes part in the immune injury process of HT. To explore whether the TSHβ splice variant participates in the homeostasis regulation of thyroid hormone, in vitro and in vivo experiments will be performed by using recombined rhTSHβ splice variant. To clear whether the TSHβ splice variant is related with the pathogenesis of HT, the expression variants of the TSHβ splice variant will be detected in thyroid tissue from HT patients. What kind of cells express the TSHβ splice variant will be comfirmed in the destructed thyroid from HT patients. NF-κB plays a key role in immune injury of thyroid in HT patients. We speculated a transcription factor NF-κB binding domain in the promoter region of the human TSHβ splice variant. To know whether the expression of TSHβ splice variant is regulated by NF-κB is very importand to explore the more extensive pathologic and physiologic function of the hTSHβ splice variant. In a word, the study will be benefit to clear some important biological characteristics of the immune-derived TSHβ splice variant ; to provide new insights into the pathogenesis and clinical prevention and therapy of HT; to know the molecular mechanism behind the expression regulation of the TSHβ splice variant by NF-κB; to be highly valuable for academic study to full understanding of the complex neuro-endocrine-immune network regulation mechanism.

2009年Vincent等报道了小鼠第一个功能性TSHβ剪接变体（TSHβv）并发现T3D呼肠病毒感染C57BL/6小鼠甲状腺中该变体表达上调7倍；我们在正常甲状腺和桥本甲状腺炎（HT）患者病变甲状腺组织中仅检测到TSHβv表达而未检出天然型TSHβ表达，且证实HT患者外周血白细胞存在TSHβv表达异常升高；上述研究提示TSHβv可能参与了HT时甲状腺的病理损伤过程。目前，有关TSHβv的许多重要生物学特性及其在HT时甲状腺免疫损伤过程中的作用尚未阐明。本项目拟通过rhTSHβv体内、外实验探讨TSHβv在调节甲状腺激素内稳态中的作用；通过研究TSHβv在HT患者甲状腺中的异常表达验证其与HT发病相关性；通过确定HT患者病变甲状腺中异常表达TSHβv的精确细胞类型探索该变体在免疫－甲状腺网络中的作用；通过验证NF-κB是否以及如何调控TSHβv表达深入认识TSHβv表达调控的分子机制。研究结果对阐明免疫－甲状腺网络调控机制具有重要学术价值，为HT的发病机制研究和治疗提供新线索。

2009年Vincent等报道了小鼠第一个功能性TSHβ剪接变体（TSHβv）并发现呼肠病毒感染小鼠甲状腺中该变体表达上调7倍；我们在正常甲状腺和桥本甲状腺炎（HT）患者病变甲状腺组织中仅检测到TSHβv表达而未检出天然型TSHβ表达，且证实HT患者外周血白细胞存在TSHβv表达异常升高；上述研究提示TSHβv可能参与了HT时甲状腺的病理损伤过程。本项目通过研究TSHβv在HT患者甲状腺中的异常表达验证其与HT发病相关性；通过确定HT患者病变甲状腺中异常表达TSHβv的精确细胞类型探索该变体在免疫－甲状腺网络中的作用；通过TSHβv体内、外实验探讨TSHβv在调节甲状腺激素内稳态中的作用；通过验证NF-κB是否调控TSHβv表达深入认识TSHβv表达调控的分子机制。研究结果证实功能性TSHβv在桥本甲状腺炎患者病变甲状腺组织中存在异常高表达且其表达与甲状腺病变损伤程度成正相关，而功能性TSHβv在结节性甲状腺肿、甲状腺腺瘤及甲状腺乳头状癌病变组织中表达差异不具有统计学意义，表明其可能与甲状腺增生性疾病及原发肿瘤的发生不密切相关。确定了HT患者病变甲状腺中异常表达功能性TSHβv的精确细胞类型是浆细胞，本项研究意义在于证实了这个TSHβv为免疫系统来源。TSHβv体内与体外实验均证实了功能性TSH剪接变体可以促进甲状腺激素合成与分泌且免疫系统来源的功能性TSHβv不受HTP轴调控，其与全长TSHβ不同，存在自身独特的表达调控机制。预测的NF-κB调控通路已证实与功能性TSHβv的表达调控无关，TSHβv在免疫损伤过程中的表达上调应该是通过其它信号传导通路进行调控的。总之，本研究结果对阐明免疫－甲状腺网络调控机制具有重要学术价值，为HT的发病机制研究和治疗提供新线索。