Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, QiXiangTai Road No22, HePing District, Tianjin 300070, China.
Mol Biol Rep. 2012 Dec;39(12):10019-30. doi: 10.1007/s11033-012-1871-x. Epub 2012 Jul 3.
Thyrotropin (TSH) is a protein that plays a key role in the control of thyroid function. TSH consists of a common α-subunit and a unique β-subunit; the latter is responsible for hormone specificity. A novel splice variant of human TSHβ was identified in 2009. To date, only the tissue distribution of the human TSHβ splice variant mRNA has been studied. Therefore, we aimed to characterize the protein translated from this splice variant. Salting-out, dialysis and concentration of serum proteins were followed by immunoprecipitation to identify the hTSHβ splice variant in serum. Stable CHO cell lines expressing the hTSHβ splice variant and V5-hTSHα were generated. After co-culture, co-immunoprecipitation was used to determine if the hTSHβ splice variant can dimerise with TSHα. We showed for the first time that the hTSHβ splice variant exists in human serum and dimerises with TSHα. To explore the relationship between the TSHβ splice variant and the pathogenesis of autoimmune thyroiditis, we assessed variations in the mRNA expression of the TSHβ splice variant in the peripheral blood leukocytes (PBLs) of Hashimoto's thyroiditis (HT) patients using quantitative RT-PCR. We found that the mRNA expression levels of the TSHβ splice variant were higher in the PBLs of HT patients who were not undergoing prednisone therapy (n = 10, P < 0.0001) and in the PBLs of HT patients with a longer duration of illness (>18 months) who were undergoing prednisone therapy (n = 5, P = 0.023) than in those of the control group. This pattern was reversed in the PBLs of HT patients with a shorter duration of illness (<9 months) who were undergoing prednisone therapy (n = 8, P < 0.0001). Dexamethasone inhibition of the TSHβ splice variant mRNA expression occurred in a dose- and time-dependent manner. These results demonstrated that the TSHβ splice variant may participate in the pathogenesis of HT.
促甲状腺激素（TSH）是一种在甲状腺功能控制中起关键作用的蛋白质。TSH 由一个共同的α亚基和一个独特的β亚基组成；后者负责激素特异性。2009 年，人们在人类 TSHβ 中鉴定出一种新的剪接变异体。迄今为止，仅研究了人类 TSHβ 剪接变异体 mRNA 的组织分布。因此，我们旨在表征从这种剪接变异体翻译的蛋白质。盐析、透析和血清蛋白浓缩后，通过免疫沉淀鉴定血清中的 hTSHβ 剪接变异体。生成表达 hTSHβ 剪接变异体和 V5-hTSHα 的稳定 CHO 细胞系。共培养后，共免疫沉淀用于确定 hTSHβ 剪接变异体是否可以与 TSHα 二聚化。我们首次表明 hTSHβ 剪接变异体存在于人类血清中，并与 TSHα 二聚化。为了探讨 TSHβ 剪接变异体与自身免疫性甲状腺炎发病机制的关系，我们使用定量 RT-PCR 评估了桥本甲状腺炎（HT）患者外周血白细胞（PBL）中 TSHβ 剪接变异体的 mRNA 表达变化。我们发现，未接受泼尼松治疗的 HT 患者（n = 10，P < 0.0001）和接受泼尼松治疗且病程较长（>18 个月）的 HT 患者（n = 5，P = 0.023）的 PBL 中 TSHβ 剪接变异体的 mRNA 表达水平更高，与对照组相比。病程较短（<9 个月）且正在接受泼尼松治疗的 HT 患者（n = 8，P < 0.0001）的 PBL 中出现相反模式。地塞米松抑制 TSHβ 剪接变异体 mRNA 表达呈剂量和时间依赖性。这些结果表明，TSHβ 剪接变异体可能参与 HT 的发病机制。
