Highly Potent Peptide Therapeutics To Prevent Protein Aggregation In Huntington s Disease

Abstract

Huntingtons disease (HD) is a progressive, autosomal dominant neurodegenerative disorder resulting from a significant amplification of CAG repeats in exon 1 of the Huntingtin (Htt) gene. More than 36 CAG repeats result in the formation of mutant Htt (mHtt) protein. These amino-terminal mHtt fragments lead to the formation of misfolded proteins, which then form aggregates in relevant brain regions. Available treatments concentrate primarily on alleviating the diseases symptoms. Therefore, therapies that can delay the progression of the disease are imperative to halt the course of the disease. Peptide-based drug therapies provide such a platform. Inhibitory peptides were screened against monomeric units of both wild type (Htt(Q25)) and mHtt fragments, including Htt(Q46)and Htt(Q103). It was accomplished by utilizing several display technologies. This study focuses on the in-vitro characterization of the screened peptides. Fibril kinetics was studied in real-time utilizing the Thioflavin T (ThT) assay. The impact of specific peptides on fibril formation was examined by observing the change in fluorescence signal. Atomic force microscopy was also used to study the influence of peptides on fibril formation. Three of the six chosen peptides (HHGANSLSLVSQD, HGLHSMHNKLTR, and WMFPSLKLLDYH) effectively inhibited aggregation. These experiments demonstrate that the chosen peptides suppress the formation of fibrils in mHtt proteins and can provide a therapeutic lead for further optimization and development.