GENETIC SUSCEPTIBILITY TO GRAVES'-LIKE HYPERTHYROIDISM IN MICE

描述（由申请人提供）：Graves甲亢是由促甲状腺激素受体（TSHR）的甲状腺刺激性自身抗体（TSAb）引起的。一些小鼠品系对TSHR-腺病毒免疫诱导的甲状腺功能亢进症易感，而一些小鼠品系对TSHR-腺病毒免疫诱导的甲状腺功能亢进症耐受。这种差异允许分析小鼠甲状腺功能亢进症的遗传易感性。重组近交系（RI）小鼠是由两个品系的后代重复的兄弟×姐妹交配衍生的稳定品系。我们对CXB和BXH RI株基因型的研究表明，诱导的TSHR抗体和甲状腺功能亢进受不同染色体位点的影响。我们将在这些调查结果的基础上开展以下工作： 1.甲状腺基线参数和对刺激的反应性的遗传控制：为了深入了解这些参数的遗传易感性，我们将通过以下方法研究来自血清T4和Tg值不同的亲本品系的RI小鼠：测定BXH和BXD RI小鼠组在基线和TSH刺激后的T4和Tg水平。进行连锁分析，以确定负责T4，Tg和TSH变异的染色体和基因座。 2. TSHR抗体作为对TSHR免疫的量度。将用TSHR-腺病毒免疫AXB/BXA和DXB RI小鼠，这些小鼠来自TSHR抗体应答不同的亲本品系（对于两个RI组，分别为A对B6和DBA/2对B6），以： 通过TSH结合抑制、TSAb和ELISA测定诱导的TSHR抗体水平。 将使用表达人和小鼠TSHR的CHO细胞比较TSAb生物活性。 通过连锁分析确定与这些性状相关的染色体/基因座。3.甲状腺刺激抗体（TSAb）诱导的甲状腺功能亢进症易感性。我们将进行以下研究： 用TSHR-腺病毒免疫RI小鼠的AXB/BXA和BXD组。为了克服BXD小鼠对诱导的甲状腺功能亢进症的抗性，我们将在TSHR-腺病毒免疫之前耗尽Treg。 确定AXB/BXA和BXD株中影响i抗体诱导的甲状腺功能亢进的染色体/位点。 总体而言，这些小鼠研究将为未来研究提供基础，完善遗传位点，并为人类基因组全阵列分析中Graves患者的表型分层方法提供见解 公共卫生相关性：Graves'甲状腺功能亢进症是由促甲状腺激素受体（TSHR）的甲状腺刺激抗体引起的，这些抗体模拟TSH的刺激。这种疾病是多基因的，但在大的患者群体中进行全基因组扫描，除了MHC外，未能发现共同的基因。我们将在基因分型的近交系小鼠中使用Graves'甲状腺功能亢进症的诱导模型来建立TSHR抗体和血清甲状腺素升高的遗传基础，目的是为将来的人类全基因组阵列分析提供对Graves'患者亚群的深入了解。

DESCRIPTION (provided by applicant): Graves' hyperthyroidism is caused by thyroid stimulating autoantibodies (TSAb) to the thyrotropin receptor (TSHR). Some mouse strains are susceptible, and some are resistant, to developing hyperthyroidism induced by TSHR- adenovirus immunization. This difference permits analyzing the genetic susceptibility to hyperthyroidism in mice. Recombinant inbred (RI) mice are stable lines derived by repeated brother x sister matings of the progeny of two strains. Our studies in genotyped CXB and BXH RI strains revealed that induced TSHR antibodies and hyperthyroidism are influenced by different chromosomal loci. We will build on these findings as follows: 1. Genetic controlofthyroidbaseline parameters and responsiveness to stimulation : To obtain insight into the genetic susceptibility for these parameters, we will study RI mice derived from parental strains differing in serum T4 and Tg values by: Determining T4 and Tg levels at baseline and after TSH stimulation in BXH and BXD RI sets of mice. Performing linkage analysis to identify chromosomes and loci responsible for variability in T4, Tg and TSH. 2. TSHR antibodies as a measure of immunity to the TSHR . AXB/BXA and DXB RI mice, derived fromparental strains differing in TSHR antibody responses (A versus B6 and DBA/2 versus B6 for the two RI sets, respectively) will be immunized with TSHR-adenovirus to: Determine induced TSHR antibody levels measured as TSH binding inhibition, TSAb and ELISA. TSAb bioactivity will be compared using CHO cells expressing human and mouse TSHR. Identify by linkage analysis the chromosomes/loci associated with these traits. 3. Susceptibility to hyperthyroidism induced by thyroid stimulating antibodies (TSAb). We will perform the following studies: Immunize AXB/BXA and BXD sets of RI mice with TSHR-adenovirus. To overcome resistance to induced hyperthyroidism in BXD mice, we will deplete Treg before TSHR-adenovirus immunization. Determine chromosomes/loci influencing iantibody induced hyperthyroidism in AXB/BXA and BXD strains. Overall, these studies in mice will provide the basis for future studies refining genetic loci and provide insight into approaches for phenotypic stratification of Graves' patients in human genome wide array analyses PUBLIC HEALTH RELEVANCE: Graves' hyperthyroidism is caused by thyroid stimulating antibodies to the thyrotropin receptor (TSHR) that mimic stimulation by TSH. The disease is multigenic but genome wide scans in large patient groups fail to reveal common genes except for MHC. We will use an induced model of Graves' hyperthyroidism in genetically typed inbred mice to establish the genetic basis for the development of TSHR antibodies and elevated serum thyroxine with the goal of providing insight into subsetting Graves' patients for future human genome wide array analyses.