转甲状腺素蛋白（TTR）从人体细胞分泌至血浆中会发生错误折叠、聚集和沉淀，进而引起家族型淀粉样多发性神经病和老年型心肌病。TTR错误折叠状态的检测对疾病的早期诊断和机理研究十分重要。现有荧光检测方法无法有效地检测血浆中TTR的早期错误折叠态，导致此类疾病的致病机理不清晰。本项目采用重组TTR与荧光基团偶联的共轭大分子作为新型探针解决上述技术问题。新方法利用重组TTR作为探针的一部分，保证了探针在血浆中有选择性地结合错误折叠的TTR。此外，与TTR偶联的新型环境敏感荧光分子在TTR错误折叠时发出强烈荧光。二者联用作为探针可以实现血浆中TTR早期错误折叠态的荧光检测。此项目的成功将为阐释TTR早期错误折叠态的致病机制奠定技术基础。初始数据已经证明了此项目的可行性。

Transthyretin that secrets from human cells into blood plasma can misfold, aggregate, and deposit across different tissues, leading to familial amyloid polyneuropathy and senile amyloid cardiomyopathy. Accurate detection of the early-stage misfolded transthyretin in blood plasma is essential for early diagnosis of these diseases and our understanding of pathogenic mechanisms. Current fluorescence-based methods to detect misfolded proteins in blood plasma utilize either conformation specific antibodies or fluorescent dyes, neither of which can probe misfolded transthyretin effectively. Towards this goal, we propose to develop a novel strategy using transthyretin-fluorophore conjugate as a fluorogenic probe to detect misfolded transthyretin in blood plasma. Introduction of recombinant transthyretin improves selectivity of the conjugate probe, as it will bind to other misfolded transthyretin originally in blood plasma. Meanwhile, de novo designed environment-sensitive fluorophores enhance the sensitivity of the conjugate probe towards misfolded species. Success of such a fluorogenic method will provide mechanistic insight of senile amyloid cardiomyopathy caused by the misfolding and aggregation of transthyretin. Our initial results support the feasibility of this proposal.