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CSTB gene replacement improves neuroinflammation, neurodegeneration and ataxia in murine type 1 progressive myoclonus epilepsy


EPM1 is the most common form of Progressive Myoclonus Epilepsy characterized by late-childhood onset, ever-worsening and disabling myoclonus, seizures, ataxia, psychiatric disease, and shortened lifespan. EPM1 is caused by expansions of a dodecamer repeat sequence in the promoter of CSTB (cystatin B), which dramatically reduces, but does not eliminate, gene expression. The relatively late onset and consistent presence of a minimal amount of protein product makes EPM1 a favorable target for gene replacement therapy. If treated early, these children’s normally developed brains could be rescued from the neurodegeneration that otherwise follows, and their cross-reactive immunological material (CRIM) positive status greatly reduces transgene related toxicity. We performed a proof-of-concept CSTB gene replacement study in Cstb knockout mice by introducing full-length human CSTB driven by the CBh promoter packaged in AAV9 and administered at postnatal days 21 and 60. Mice were sacrificed at 2 or 9 months of age, respectively. We observed significant improvements in expression levels of neuroinflammatory pathway genes and cerebellar granule cell layer apoptosis, as well as amelioration of motor impairment. The data suggest that gene replacement is a promising therapeutic modality for EPM1 and could spare affected children and families the ravages of this otherwise severe neurodegenerative disease.

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Fig. 1: Schematic of study design.
Fig. 2: Human CSTB protein expression is detected in the mouse brain.
Fig. 3: CSTB expression lowers expression of early-onset neuroinflammation markers.
Fig. 4: AAV-CSTB gene replacement reduces neuronal apoptosis but does not prevent brain atrophy.
Fig. 5: The effect of AAV-CSTB gene therapy on the performance of Cstb−/− mice in the rotarod test.

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All raw data used to prepare this manuscript is available upon contacting corresponding author.


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This work was funded by Ultragenyx and Hope for ULD. We thank the UT Southwestern Histopathology (Dr. John Shelton), Whole Brain Microscopy (Dr. Denise Ramirez), Rodent Behavior core (Dr. Shari Birnbaum) and Neuro-Models facility (Dr. Erik Plautz) for assistance with tissue processing, imaging, the rotarod test and video-electrocorticography, respectively. BAM holds the University of Texas Southwestern Jimmy Elizabeth Westcott Chair in Pediatric Neurology.

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BAM and EG designed the project. BAM wrote the manuscript. EG, SK, and MV conducted the experiments, analyzed the data, and helped write the manuscript. DVA, UM, and XC helped in parts of experiments. SFM, AL, and SJG provided feedback and reviewed the manuscript. BAM supervised the project.

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Correspondence to Berge A. Minassian.

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Gumusgoz, E., Kasiri, S., Verma, M. et al. CSTB gene replacement improves neuroinflammation, neurodegeneration and ataxia in murine type 1 progressive myoclonus epilepsy. Gene Ther 31, 234–241 (2024).

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