Interferon-gamma: its role in autoimmune thyroiditis and thyroid function

干扰素-γ：其在自身免疫性甲状腺炎和甲状腺功能中的作用

• 批准号: 7122047
• 负责人: PATRIZIO CATUREGLI
• 金额: $ 27.95万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7122047
• 关键词: 3T3 cells; B lymphocyte; T lymphocyte; autoimmune thyroiditis; biological signal transduction; electron microscopy; gene expression; gene targeting; genetic promoter element; genetic transcription; genetically modified animals; hormone biosynthesis; hypothyroidism; interferon gamma; laboratory mouse; membrane transport proteins; nucleic acid sequence; pathologic process; polymerase chain reaction; proteasome; serial analysis of gene expression; thyroglobulin; thyroid function; thyroid hormones; transfection

Interferon gamma (IFNgamma) has been implicated in the pathogenesis of autoimmune (Hashimoto's) thyroiditis. We have generated transgenic mice that express IFNg specifically in the thyroid gland, and shown that IFNgamma a) directly induces primary hypothyroidism with decreased NIS expression; b) induces Hurthle cells-like and increase thyroidal fat; c) protects from autoimmune thyroiditis. Specific aim 1 is to test the hypothesis that the IFNg-driven activation of the immunoproteasome is critical to the ontogeny of Hurthle cells. We will: i) test whether pharmacologic or genetic blocks of the immunoproteasome inhibit the appearance of Hurthle cells; ii) evaluate in situ immunoproteasome expression in thyroids from thyr-IFNgamma transgenic mice, as well as from patients with Hurthle cell lesions. Specific aim 2 is to unravel the mechanism through which IFNgamma protects from autoimmune thyroiditis. We hypothesize that this protective effect is mediated by a caspase-8 dependent activation of apoptosis, which results in death of autoreactive, thyroid-specific lymphocytes. We will transduce autoreactive T cells with an inactive form of caspase-8 and adoptively transfer T cells to wild type or thyr-IFNgamma transgenic hosts, assessing thereafter the incidence and severity of thyroiditis. We wil also cross thyr-IFNgamma transgenics to knockout mice that lack IRF-1 or IRF-4, two critical transcription factors linking IFNgamma signaling with caspase-8 dependent apoptosis. Specific aim 3 is to study the interaction between IFNg interleukin-12 (IL-12) on thyroid autoimmunity and function. We have generated transgenic mice that express IL-12 specifically in the thyroid gland. The mice develop spontaneously lymphocytic thyroiditis and primary hypothyroidism with increased NIS expression. We will cross thyr-IL-12 transgenics to thyr-IFNg transgenics to assess whether the disease suppressive effect of IFNgamma prevails on the disease-promoting effect of IL-12, and whether IFNg and IL-12 synergistically induce a more severe form of hypothyroidism. Specific aim 4 is to investigate why thyroids from thyr-IFNg transgenic contain an increased number of adipocytes, and to assess whether this increase influences thyroid function. We hypothesize that thyroid macrophages primed in vivo by IFNg promote differentiation of stromal preadipocytes into mature adipocytes. We will co-culture thyroid macrophages from transgenics and controls with syngeneic pre-adipocytes, monitoring acquisition of morphological features typical of adipocytes. We also hypothesize that augmented TSH signaling is required to induce the adipocyte-rich phenotype, and cross thyr-IFNg transgenics to TSH receptor knockout mice.

干扰素 γ (IFNgamma) 与自身免疫性（桥本氏）甲状腺炎的发病机制有关。我们已经培育出在甲状腺中特异性表达 IFNg 的转基因小鼠，并表明 IFNgamma a) 直接诱导原发性甲状腺功能减退症，并减少 NIS 表达； b) 诱导Hurthle细胞样并增加甲状腺脂肪； c) 预防自身免疫性甲状腺炎。具体目标 1 是检验以下假设：IFNg 驱动的免疫蛋白酶体激活对于 Hurthle 细胞的个体发育至关重要。我们将： i) 测试免疫蛋白酶体的药理学或遗传块是否会抑制 Hurthle 细胞的出现； ii) 评估 thyr-IFNγ 转基因小鼠以及 Hurthle 细胞病变患者甲状腺中的原位免疫蛋白酶体表达。具体目标 2 是揭示 IFNgamma 预防自身免疫性甲状腺炎的机制。我们假设这种保护作用是由 caspase-8 依赖性细胞凋亡激活介导的，从而导致自身反应性甲状腺特异性淋巴细胞死亡。我们将用非活性形式的 caspase-8 转导自身反应性 T 细胞，并将 T 细胞过继转移至野生型或 thyr-IFNgamma 转基因宿主，然后评估甲状腺炎的发病率和严重程度。我们还将 Tyr-IFNgamma 转基因与缺乏 IRF-1 或 IRF-4 的敲除小鼠杂交，IRF-1 或 IRF-4 是连接 IFNgamma 信号传导与 caspase-8 依赖性细胞凋亡的两个关键转录因子。具体目标3是研究IFNg白细胞介素12（IL-12）对甲状腺自身免疫和功能的相互作用。我们已经培育出在甲状腺中特异性表达 IL-12 的转基因小鼠。小鼠出现自发性淋巴细胞性甲状腺炎和原发性甲状腺功能减退症，并伴有 NIS 表达增加。我们将 thyr-IL-12 转基因与 thyr-IFNg 转基因杂交，以评估 IFNgamma 的疾病抑制作用是否优于 IL-12 的疾病促进作用，以及 IFNg 和 IL-12 是否协同诱导更严重的甲状腺功能减退症。具体目标4是研究为什么来自thyr-IFNg转基因的甲状腺含有增加数量的脂肪细胞，并评估这种增加是否影响甲状腺功能。我们假设体内由 IFNg 引发的甲状腺巨噬细胞促进基质前脂肪细胞分化为成熟脂肪细胞。我们将来自转基因和对照的甲状腺巨噬细胞与同基因前脂肪细胞共培养，监测脂肪细胞典型形态特征的获得。我们还假设需要增强 TSH 信号传导来诱导富含脂肪细胞的表型，并将 thyr-IFNg 转基因与 TSH 受体敲除小鼠交叉。