Exploring mechanisms of TDP-43 aggregation and disaggregation

描述（由申请人提供）：探索TDP-43的聚集和分解一系列看似不同的神经退行性疾病现在被一个共同的潜在主题所统一：非淀粉样蛋白、泛素化的TDP-43包涵体在中枢神经系统中的积累。这些致死性疾病包括肌萎缩性侧索硬化症（ALS）和伴有泛素阳性包络物（FTLD-U）的额叶颞叶痴呆。TDP-43基因突变的分离证实了TDP-43在ALS发病机制中的致病作用，TDP-43基因突变与家族性和散发性ALS有关。此外，TDP-43蛋白病变的酵母模型已经建立了TDP-43聚集与毒性之间的直接联系。然而，TDP-43聚集的机制基础以及als相关突变如何直接影响聚集过程尚不清楚。此外，是否有细胞因子可以拮抗或逆转聚集过程仍然未知。我们对两种AAA+ atp酶Hsp104和p97如何拮抗或逆转TDP-43聚集特别感兴趣。Hsp104溶解并重新激活变性聚集体中的蛋白质。p97阻止模型底物的聚集，p97的突变与TDP-43形成核内聚集的条件有关。我们假设，了解这些问题将大大提高我们对ALS和相关疾病的理解。因此，我们的目标是：(1)在体外使用纯组分确定TDP-43聚集的机制。(2)用Hsp104和p97体外拮抗和逆转TDP-43聚集。(3)防止或逆转TDP- 43在体内的聚集和毒性。这些研究将为TDP-43的聚集和毒性以及如何拮抗提供重要的新机制见解。我们的目标的实现将推动ALS和其他TDP-43蛋白病变治疗方法的发展。

DESCRIPTION (provided by applicant): Exploring TDP-43 aggregation and disaggregation A spectrum of seemingly diverse neurodegenerative disorders is now unified by a common underlying theme: the accumulation of non-amyloid, ubiquitylated TDP-43 inclusions in the central nervous system. These lethal disorders range from amyotrophic lateral sclerosis (ALS) to frontal temporal dementia lobar degeneration with ubiquitin positive inclusions (FTLD-U). A causative role for TDP-43 in ALS pathogenesis has been validated by the isolation of mutations in the TDP-43 gene, which are associated with familial and sporadic forms of ALS. Moreover, a yeast model of TDP-43 proteinopathies has established a direct connection between TDP-43 aggregation and toxicity. However, the mechanistic basis of TDP-43 aggregation and how ALS-associated mutations affect the aggregation process directly remain unclear. Further, whether there are cellular factors that can antagonize or reverse the aggregation process remains unknown. We are particularly interested in how two AAA+ ATPases, Hsp104 and p97, might antagonize or reverse TDP-43 aggregation. Hsp104 solubilizes and reactivates proteins from denatured aggregates. p97 prevents aggregation of model substrates, and mutations in p97 are linked with conditions where TDP-43 forms intranuclear aggregates. We hypothesize that understanding these issues will greatly enhance our understanding of ALS and related disorders. Hence, we aim to: (1) Define the mechanisms of TDP-43 aggregation using pure components in vitro. (2) Antagonize and reverse TDP-43 aggregation with Hsp104 and p97 in vitro. (3) Prevent or reverse TDP- 43 aggregation and toxicity in vivo. These studies will provide important new mechanistic insights into TDP-43 aggregation and toxicity and how this might be antagonized. Realization of our objectives will empower the development of therapies for ALS and other TDP-43 proteinopathies. PUBLIC HEALTH RELEVANCE: Several devastating diseases that are caused by nerve degeneration, including amyotrophic lateral sclerosis (ALS), have been unified by a common underlying theme: the clumping of a protein, TDP-43, in nerve cells. Our proposed studies aim to provide new mechanistic insights into how TDP-43 clumps and is toxic, and how this process might be antagonized or reversed. Realization of our objectives will empower the development of new therapies for ALS and related disorders, which are currently untreatable.