Epigenetic Dysregulation in Huntington's Disease — Therapeutic Targeting

SUMMARY

# Epigenetic Dysregulation in Huntington's Disease — Therapeutic Targeting ## Background and Rationale Huntington's disease (HD) is a devastating neurodegenerative disorder caused by CAG repeat expansion in the huntingtin (HTT) gene, leading to progressive motor, cognitive, and psychiatric decline. While the genetic basis is well-established, emerging evidence suggests that epigenetic dysregulation plays a crucial mechanistic role in HD pathogenesis and represents a promising therapeutic target.

METHODOLOGY NOTES

Phase 1 (Months 1-6): Generate iPSCs from 20 HD patients (CAG 40-55 repeats) and 20 age-matched controls using episomal vectors. Differentiate iPSCs to striatal medium spiny neurons using established protocols with BDNF, cAMP, and valproic acid. Validate neuronal identity via immunostaining for DARPP-32 and CTIP2. Phase 2 (Months 7-12): Perform comprehensive epigenomic profiling on iPSC-neurons at 8-week differentiation. Conduct whole-genome bisulfite sequencing (WGBS) for DNA methylation, ChIP-seq for H3K4me3, H3K27me3, H3K27ac, and H3K9me3 histone marks, ATAC-seq for chromatin accessibility, and RNA-seq for transcriptome analysis. Process 6 biological replicates per condition. Phase 3 (Months 13-18): Design and validate CRISPR-dCas9-based epigenome editing tools targeting dysregulated loci identified in Phase 2. Use dCas9-DNMT3A, dCas9-TET2, dCas9-p300, and dCas9-LSD1 constructs. Transfect HD iPSC-neurons and assess rescue of epigenetic marks and gene expression via qRT-PCR and targe