Preclinical evaluation of antisense oligonucleotide therapy in a mouse model of HNRNPH2-related neurodevelopmental disorder

Mutations in HNRNPH2 are associated with an X-linked disorder characterized by developmental delay, intellectual disability, motor and gait disturbances, and seizures. Murine models that reproduce key clinical features of HNRNPH2-related neurodevelopmental disorder suggest that it may result from a toxic gain of function of the mutant protein or a complex loss of normal HNRNPH2 function with impaired compensation by its homolog, HNRNPH1. In this study, we tested gapmer antisense oligonucleotides (ASOs) that target murine Hnrnph2 in a non-allele-specific manner. The lead ASO reduced Hnrnph2 mRNA and protein levels while inducing compensatory upregulation of Hnrnph1 in both WT and Hnrnph2 mutant mouse brains. A single intracerebroventricular injection of the Hnrnph2 ASO into neonatal mutant Hnrnph2 mice rescued molecular and audiogenic seizure phenotypes and improved motor and cognitive functions. ASO treatment at the juvenile stage also rescued audiogenic seizures and motor deficits. In contrast, Hnrnph2 ASO administration did not improve survival, body weight, or hydrocephalus. In human iPSC-derived neurons, a human-specific HNRNPH2 research ASO reduced HNRNPH2 and upregulated HNRNPH1 mRNA levels. Overall design: Gene expression profiling analysis were performed while treated Hnrnph2 P209L and R206W hemizygous males and WT littermates with a single bolus ICV injection of 30 µg control ASO or Hnrnph2 ASO at PND 2-4 and collected whole brains at 3 weeks of age or 8 weeks of age (n=3 per grpup).