Sviluppo di terapie a base di acidi nucleici per disturbi correlati ad ASXL3 e CHCHD10

Aim of this work is to develop nucleic acid-based therapeutic strategies for ASXL3- and CHCHD10-related neurological disorders. ASXL3 gene encodes Putative Polycomb group protein that is involved in epigenetic mechanisms, transcriptional regulation, and in maintaining homeotic gene repression as development progresses. ASXL3-related disorder is an autosomal dominant disease caused by de novo heterozygous pathogenic variants in ASXL3 gene, resulting in loss-of-function. It is associated with a non-specific neurodevelopmental phenotype characterized by neurodevelopmental delay with significantly limited speech, intellectual disability, autistic features, neuro-behavioral issues, hypotonia, feeding difficulties, and facial dysmorphism. In collaboration with the Sanders Lab (IDRM, University of Oxford), we have identified that one of the isoforms ASXL3 gene produces is a poison exon that contains a premature termination codon causing haploinsufficiency and is highly expressed in human brains. The treatment strategy investigated is based on the use of steric block MOE ASOs targeting the poison exon to increase gene expression. CHCHD10 gene encodes an intermembrane space mitochondrial protein enriched at cristae junctions that plays a role in maintaining mitochondrial integrity. CHCHD10-related disorders refer to a spectrum of neurologic phenotypes, including mitochondrial DNA instability disease, frontotemporal dementia-amyotrophic lateral sclerosis (FTD-ALS) clinical spectrum, late-onset spinal motor neuropathy (SMAJ), Charcot-Marie-Tooth disease type 2 (CMT2), and autosomal dominant isolated mitochondrial myopathy (IMMD), caused by heterozygous pathogenic variants in CHCHD10 gene inherited in an autosomal dominant manner, and that result in diseases by a toxic gain-of-function mechanism. The therapeutic approach explored focuses on the use of partial PS backbone, MOE gapmer ASOs targeting CHCHD10 trying to knock it down to potentially alleviate the phenotype, lowering toxic CHCHD10 mutant protein levels.