Development and validation of a bi-functional helical peptide: a novel strategy to inhibit TDP-43 aggregates

About This Grant

Abstract Pathologic pathophysiology of Alzheimer Disease and related dementias (ADRDs). mislocalization and aggregation o TDP-43, an essential RNA/DNA-binding protein, is central to the of ALS, frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP), TDP-43 misregulation disrupts f and is a feature splicing, mRNA stability and transport, therebyimpairing neuronal function.Recent NMR and cryo-electron microscopy studies suggest that formation of TDP-43 fibrillar aggregates is facilitated by destabilization of an α-helical segment within the amyloidogenic core of TDP-43 C-terminal domain (CTD). This core region is necessary and sufficient for TDP- 43 aggregate formation in cells and in vivo, and is able to template aggregation of full-length TDP-43, suggesting a key role in regulating the structural transition of TDP-43 to amyloid-like conformations. We used a computational approach to generate novel peptides (50 residues in length) that exhibit enhanced α-helical secondary structure and bind to TDP-43's amyloidogenic core but resist β-sheet conversion. effectively that aggregate added enabling and engineered of This strategy caps the growth of fibrils and blocks further addition of TDP-43 monomers. Our preliminary data show co-expression of our top hit engineered peptides with TDP-43's aggregation-prone CTD reduce TDP-43 formation in mammalian cells and filter trap assay. In the next step of preclinical development, we a protein degradation motif to our engineered peptide, providing extra potential therapeutic efficacy by clearance of peptide-bound fibrils. The goal of this proposal is to examine target engagement, efficacy, potential off-target effects of our top ranked peptides in vitro and in vivo. We will test the hypothesis t hat our helical peptides function as: 1) novel capping agents that robustly bind and effectively inhibit growth TDP-43 fibrillar aggregates and2) bi-functional degraders of TDP-43 aggregates without adversely affecting physiologic function and localization of endogenous TDP-43. In Aim 1 we will evaluate our engineered helical peptides for target engagement and efficacy in reducing TDP-43 aggregates. Aim 2 will examine efficacy of engineered helical peptides for clearing TDP-43 aggregates in vivo and evaluate endogenous TDP-43 function. Upon successful completion, this project will determine whether our engineered helical peptides hold promise for further preclinical testing in mammalian in vivo models and opens avenues for targeting traditionally “undruggable” proteins.