Allele-Specific Protein-Based Therapeutics for Myotrophic Lateral Sclerosis Associated with C9ORF72 Repeat Expansions
Abstract
Although the association of expanded arrays of a GGGGCC (hereinafter referred to as G4C2) hexanucleotide sequence in intron 1 of the C9orf72 locus is observed in up to 40 of familial cases of ALS, the molecular pathways adversely impacted by the G4C2 expansion have not been clearly defined. Current hypotheses propose that three mechanisms perhaps in combination, lead to progressive neuronal loss: (1) gain of function due the production of truncated RNA transcripts that form nuclear foci that may trap factors needed for RNA metabolism; (2) dipeptide production (DPR) from aberrant translation of G4C2 sequences in all three reading frames from RNAs transcribed in BOTH the sense and antisense directions (that form inclusion bodies in the cytoplasm that trap the transcription factor TDP-43 which inhibits TDP-43 function); and/or (3) haploinsufficiency due to epigenetic downregulation the major C9orf72 RNA species, V2. While therapies that target each specific mechanism individually show promise, current reviews argue that combinatorial therapies that at least two of the three mechanisms may yield more effective approaches for treating patients affected by ALS associated with G4C2 nucleotide expansions. Enzerna Biosciences is commercializing a novel approach to specifically bind any RNA molecule using Artificial Site-Specific RNA Endonucleases (ASREs) engineered with customized sequence specificity. ASREs are human-based chimeric proteins consisting of an RNA binding domain that specifically recognize different 8-nucleotide RNA sequences fused to an RNA endonuclease domain (Figure 2, Appendix). This unique binding mode makes PUF domain a programmable RNA-binding module that can bind to any sequence of choice. We proposed to leverage ASRE technology to create an innovative combinatorial therapy for ALS associated with G4C2 expansions. We proposed to develop ASREs that can target two of the mechanisms that lead to the deleterious consequences of the expanded C9orf72 RNA.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2023
- Accession Number
- AD1212472
Entities
People
- Joseph Ruiz