Rational Design of TDP-43 Derived α-Helical Peptide Inhibitors: anIn-SilicoStrategy to Prevent TDP-43 Aggregation in Neurodegenerative Disorders

Abstract

TDP-43, an essential RNA/DNA-binding protein, is central to the pathology of neurodegenerative diseases such as Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Pathological mislocalization and aggregation of TDP-43 disrupts RNA splicing, mRNA stability, and mRNA transport, thereby impairing neuronal function and survival. The formation of amyloid-like TDP-43 filaments is largely facilitated by the destabilization of an α-helical segment within the disordered C-terminal region. In this study, we hypothesized that preventing the destabilization of the α-helical domain could potentially halt the growth of these pathological filaments. To explore this, we utilized a range ofin-silicotechniques to design and evaluate peptide-based therapeutics. Various pathological TDP-43 amyloid-like filament crystal structures were selected for their potential to inhibit the binding of additional TDP-43 monomers to the growing filaments. Our computational approaches included biophysical and secondary structure property prediction, molecular docking, 3D structure prediction, and molecular dynamics simulations. Through these techniques, we were able to assess the structure, stability, and binding affinity of these peptides in relation to pathological TDP-43 filaments. The results of ourin-silicoanalyses identified a selection of promising peptides, which displayed a stable α-helical structure, exhibited an increased number of intramolecular hydrogen bonds within the helical domain, and demonstrated high binding affinities for pathological TDP-43 amyloid-like filaments. Additionally, molecular dynamics simulations provided further support for the stability of these peptides, as they exhibited lower root mean square deviations in their helical propensity over 100ns. These findings establish α-helical propensity peptides as potential lead molecules for the development of novel therapeutics against TDP-43 aggregation. This structure-based computational approach for rational design of peptide inhibitors opens a new direction in the search for effective interventions for ALS, FTD, and other related neurodegenerative diseases. The peptides identified as the most promising candidates in this study are currently subject to further testing and validation through both in vitro and in vivo experiments.Graphical Abstract

In silicoandin vitrostudies suggest epigallocatechin gallate (EGCG), a polyphenol in green tea, can bind and modulate the aggregation and cytotoxicity of the full-length TDP-43 protein implicated in TDP-43 proteinopathies

“…Such studies have been carried out in vitro using different model systems and targeting the aggregation of different domains of TDP-43 using ligands such as nTRD22, poly-ADP-Ribose (PAR), the drug mitoxantrone and 8-hydroxyquinoline-based small molecules [10][11][12][13]. Additionally, in silico approaches towards design of inhibitors towards TDP-43 aggregation are also being strategized [14,15]. Previously, we found an imidazole containing acridine derivative, AIM4, that could prevent the in vitro aggregation of a C-terminal fragment of TDP-43, termed TDP-43 2C [16].…”