AAV9-mediated SH3TC2 gene replacement therapy targeted to Schwann cells for the treatment of CMT4C

Elena Georgiou; Alexia Kagiava; Irene Sargiannidou; Natasa Schiza; Marina Stavrou; Jan Richter; Christina Tryfonos; Amanda Heslegrave; Henrik Zetterberg; Christina Christodoulou; Kleopas A Kleopa

doi:10.1016/j.ymthe.2023.08.020

AAV9-mediated SH3TC2 gene replacement therapy targeted to Schwann cells for the treatment of CMT4C

Mol Ther. 2023 Nov 1;31(11):3290-3307. doi: 10.1016/j.ymthe.2023.08.020. Epub 2023 Aug 28.

Affiliations

¹ Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
² Molecular Virology Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
³ Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK.
⁴ Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK; Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China; Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.
⁵ Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus; Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus. Electronic address: kleopa@cing.ac.cy.

PMID: 37641403
PMCID: PMC10638072 (available on 2024-11-01)
DOI: 10.1016/j.ymthe.2023.08.020

Abstract

Type 4C Charcot-Marie-Tooth (CMT4C) demyelinating neuropathy is caused by autosomal recessive SH3TC2 gene mutations. SH3TC2 is highly expressed in myelinating Schwann cells. CMT4C is a childhood-onset progressive disease without effective treatment. Here, we generated a gene therapy for CMT4C mediated by an adeno-associated viral 9 vector (AAV9) to deliver the human SH3TC2 gene in the Sh3tc2^-/- mouse model of CMT4C. We used a minimal fragment of the myelin protein zero (Mpz) promoter (miniMpz), which was cloned and validated to achieve Schwann cell-targeted expression of SH3TC2. Following the demonstration of AAV9-miniMpz.SH3TC2myc vector efficacy to re-establish SH3TC2 expression in the peripheral nervous system, we performed an early as well as a delayed treatment trial in Sh3tc2^-/- mice. We demonstrate both after early as well as following late treatment improvements in multiple motor performance tests and nerve conduction velocities. Moreover, treatment led to normalization of the organization of the nodes of Ranvier, which is typically deficient in CMT4C patients and Sh3tc2^-/- mice, along with reduced ratios of demyelinated fibers, increased myelin thickness and reduced g-ratios at both time points of intervention. Taken together, our results provide a proof of concept for an effective and potentially translatable gene replacement therapy for CMT4C treatment.

Keywords: AAV9; Charcot-Marie-Tooth 4C; Schwann cells; gene therapy; peripheral neuropathy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Charcot-Marie-Tooth Disease* / genetics
Charcot-Marie-Tooth Disease* / therapy
Genetic Therapy*
Humans
Intracellular Signaling Peptides and Proteins* / genetics
Mice
Mutation
Schwann Cells / metabolism

Substances

Intracellular Signaling Peptides and Proteins
SH3TC2 protein, human

Supplementary concepts

Charcot-Marie-Tooth disease, Type 4C