Developing antisense oligonucleotides for a TECPR2 mutation-induced, ultra-rare neurological disorder using...

Area of Science:

• Genetics and Molecular Biology
• Neuroscience
• Rare Diseases

Background:

• Mutations in the TECPR2 gene cause an ultra-rare neurological disorder (SPG49/HSAN9) with severe symptoms including intellectual disability, motor delays, and premature death.
• The biological function of TECPR2 is poorly understood, and no disease-modifying therapies currently exist for this condition.
• A specific mutation, c.1319delT (p.Leu440Argfs*19), introduces a premature stop codon in TECPR2 exon 8, leading to a lack of functional protein.

Purpose of the Study:

• To develop and evaluate an antisense oligonucleotide (ASO) exon-skipping strategy to correct the TECPR2 c.1319delT mutation.
• To model the disease in vitro using patient-derived cells and assess the potential for restoring TECPR2 protein expression and function.
• To evaluate the in vivo tolerability and biodistribution of the lead ASO candidate in a non-human primate model.

Main Methods:

• Utilized patient-derived fibroblasts and induced pluripotent stem cell (iPSC)-derived neurons carrying the TECPR2 mutation for in vitro studies.
• Designed and screened ASOs targeting TECPR2 exon 8 to induce exon skipping and restore the reading frame.
• Assessed TECPR2 protein expression, localization in neurons, and in vivo tolerability and CNS tissue distribution of the lead ASO candidate (ASO-005-02) in cynomolgus monkeys.

Main Results:

• The developed ASO strategy successfully induced TECPR2 exon 8 skipping, restoring in-frame expression of a truncated TECPR2 protein variant (TECPR2ΔEx8).
• The lead ASO candidate (ASO-005-02) demonstrated potent activity (∼27 nM) in patient-derived fibroblasts and restored TECPR2ΔEx8 with correct punctate neuronal localization.
• ASO-005-02 showed an acceptable tolerability profile in vivo, with broad distribution across CNS tissues after intrathecal administration in monkeys.

Conclusions:

• An ASO exon-skipping approach targeting the TECPR2 c.1319delT mutation is a viable therapeutic strategy for SPG49/HSAN9.
• The developed ASO candidate (ASO-005-02) can restore TECPR2 protein expression and localization, suggesting potential functional rescue.
• This study supports the potential utility of ASO-based exon skipping for treating this rare neurological disorder, warranting further clinical investigation.