Cedars-Sinai Medical Center, Los Angeles, CA 90048; and
David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095.
J Immunol. 2019 May 1;202(9):2570-2577. doi: 10.4049/jimmunol.1900038. Epub 2019 Apr 3.
Transgenic NOD. mice that express the human (h) TSHR A-subunit in the thyroid gland spontaneously develop pathogenic TSHR autoantibodies resembling those in patients with Graves disease. Nanoparticles coupled to recombinant hTSHR A-subunit protein and a tolerogenic molecule (ligand for the endogenous aryl-hydrocarbon receptor; ITE) were injected i.p. four times at weekly intervals into hTSHR/NOD. mice with the goal of blocking TSHR Ab development. Unexpectedly, in transgenic mice, injecting TSHR A-subunit-ITE nanoparticles (not ITE-nanoparticles or buffer) accelerated and enhanced the development of pathogenic TSHR Abs measured by inhibition of TSH binding to the TSHR. Nonpathogenic TSHR Abs (ELISA) were enhanced in transgenics and induced in wild-type littermates. Serendipitously, these findings have important implications for disease pathogenesis: development of Graves TSHR Abs is limited by the availability of A-subunit protein, which is shed from membrane bound TSHR, expressed at low levels in the thyroid. The enhanced TSHR Ab response following injected TSHR A-subunit protein-nanoparticles is reminiscent of the transient increase in pathogenic TSHR Abs following the release of thyroid autoantigens after radio-iodine therapy in Graves patients. However, in the hTSHR/NOD. model, enhancement is specific for TSHR Abs, with Abs to thyroglobulin and thyroid peroxidase remaining unchanged. In conclusion, despite the inclusion of a tolerogenic molecule, injected nanoparticles coated with TSHR A-subunit protein enhanced and accelerated development of pathogenic TSHR Abs in hTSHR/NOD. NOD. These findings emphasize the need for sufficient TSHR A-subunit protein to activate the immune system and the generation of stimulatory TSHR Abs in genetically predisposed individuals.
在甲状腺中表达人（h）促甲状腺激素受体 A 亚单位的转基因 NOD. 小鼠自发产生类似于格雷夫斯病患者的致病性 TSHR 自身抗体。将与重组 hTSHR A 亚单位蛋白和耐受原分子（内源性芳香烃受体配体；ITE）偶联的纳米颗粒每周间隔一次通过腹腔内注射四次进入 hTSHR/NOD. 小鼠，目的是阻断 TSHR Ab 的发展。出乎意料的是，在转基因小鼠中，注射 TSHR A 亚单位-ITE 纳米颗粒（不是 ITE-纳米颗粒或缓冲液）加速并增强了通过抑制 TSH 与 TSHR 结合来测量的致病性 TSHR Ab 的发展。非致病性 TSHR Ab（ELISA）在转基因小鼠中增强，并在野生型同窝仔中诱导。偶然的是，这些发现对疾病发病机制具有重要意义：Graves TSHR Ab 的发展受到 A 亚单位蛋白可用性的限制，该蛋白从膜结合的 TSHR 脱落，在甲状腺中低水平表达。注射 TSHR A 亚单位蛋白纳米颗粒后 TSHR Ab 反应增强类似于 Graves 患者接受放射性碘治疗后甲状腺自身抗原释放后致病性 TSHR Ab 的短暂增加。然而，在 hTSHR/NOD. 模型中，增强是特异性的 TSHR Ab，甲状腺球蛋白和甲状腺过氧化物酶的 Ab 保持不变。总之，尽管包含了耐受原分子，但涂覆有 TSHR A 亚单位蛋白的注射纳米颗粒增强并加速了 hTSHR/NOD. 中致病性 TSHR Ab 的发展。这些发现强调了在遗传易感性个体中，需要足够的 TSHR A 亚单位蛋白来激活免疫系统并产生刺激性 TSHR Ab。
