Posttranslational Neoantigens in Autoimmunity and Metabolism in T1D

我们实验室和其他实验室正在进行的分析已经确定了自我蛋白质的新特性，即 翻译后蛋白质修饰（PTM），可被确定为早期蛋白质组学和免疫学修饰。 1型糖尿病的生物标志物以及改变代谢途径。一种新出现的自我蛋白质 获得PTM并成为导致炎症的B和T细胞自身免疫应答的靶标， 胰腺的病理对自身蛋白质的关键修饰的一些实例包括瓜氨酸， 氧化、脱酰胺反应和异戊酰基修饰，所有细胞内自身蛋白的反应， 经受炎性应激。关键的PTM候选者已经从人类β细胞中鉴定出来， 其他关键候选物将从β细胞衍生的外泌体中鉴定， β细胞健康的标志。同样重要的是，细胞内的这些PTM可以改变细胞的生物学特性。 β细胞内的蛋白质。在本提案中，我们将定义修饰的自身蛋白质如何改变 胰腺β细胞中葡萄糖传感和胰岛素分泌的酶途径。该提案将 利用多纵标光谱分析（MIMOSA），这是耶鲁大学首创的技术。MIMOSA是一个 重大创新，提供了一个内部交叉验证以及NMR验证，直接，严格， 代谢通量的综合集成分析。MIMOSA的“多坐标”方面包括： 稳定同位素沿沿着交叉代谢途径从代谢物流向代谢物。“质量” 同位素异构体”方面使用稳定同位素标记的代谢物的基于MS/MS的离子碎裂分析， 识别标签的碳特异性位置。本研究的意义和创新之处在于 通过药物校正异常的β细胞功能来鉴定可以恢复β细胞功能的途径， 修饰，以及将自身免疫生物标志物与β细胞功能障碍的途径联系起来。

Ongoing analyses from our laboratory and others have identified novel properties of self proteins, namely posttranslational protein modifications (PTMs) that may be identified as early proteomic and immunologic biomarkers of Type 1 diabetes as well as alter metabolic pathways. An emerging number of self proteins acquire PTMs and become targets of B and T cell autoimmune responses leading to inflammation and pathology in the pancreas. Some examples of critical modifications to self proteins include citrullination, oxidation, deamidation reactions, and isoaspartyl modification, all responses of self proteins within cells that undergo inflammatory stress. Key PTM candidates have already been identified from human beta cells and other key candidates will be identified from beta cell derived exosomes, recently identified as a peripheral marker of beta cell health. As importantly, these PTMs within cells may alter the biological properties of proteins within beta cells. In the present proposal, we will define how modified self-proteins may alter enzymatic pathways of glucose sensing and insulin secretion in the pancreatic beta cell. The proposal will utilize MultiOrdinate Spectral Analysis (MIMOSA), a technology pioneered at Yale University. MIMOSA is a major innovation that provides an internally cross-validated as well as NMR-validated, direct, rigorous, comprehensive integrated analysis of metabolic fluxes. The “multi-ordinate” aspect of MIMOSA incorporates the flow of stable isotope from metabolite to metabolite along intersecting metabolic pathways. The “mass isotopomer” aspect uses MS/MS-based ion fragmentation analysis of stable-isotope-labeled metabolites to identify the carbon-specific position of label. The significance and innovation of the present studies is in identifying pathways that may restore beta cell functions, via pharmaceutical correction of the aberrant modification, as well as link autoimmune biomarkers with pathways of beta cell dysfunction.