B5 - Neurologic Diseases (excluding Ophthalmic and Auditory Diseases)
1615: Rescuing STXBP1 Haploinsufficiency in Patient Derived iPSCs Using AAV Mediated Gene Replacement
Type: Poster Session
Poster Board Number: 1615
Presentation Details
Session Title: Friday Posters: Neurologic Diseases
Syntaxin-binding protein 1 (STXBP1, also known as MUNC18-1) plays an essential role in synaptic vesicle fusion and is required for neurotransmitter release, and mutations in STXBP1 are a leading cause of developmental epileptic encephalopathy. Multiple mutations in STXBP1 result in premature termination codons, causing transcript nonsense mediated decay and STXBP1 haploinsufficiency. Induced pluripotent stem cells (iPSCs) generated from isolated patient blood samples, and then differentiated into neurons, retain phenotypes of patient neurons, providing a relevant model for screening potential therapies. Given the inherit inefficiencies with standard AAVs in transducing neurons, we first assessed a range of newly discovered AAVs variants emerging from capsid screens in non-human primates (NHP) brains for their abilities to more robustly transduce iPSCs derived neurons. Several variants in this screen showed 2-3 log improved transduction relative to their respective parent serotypes. Next, we cloned and packaged full length STXBP1 cDNA into AAV variant BD004 and BD005, and transduced iPSC-neurons derived from STXBP1 patients. We showed 3-30-fold upregulation of STXBP1 mRNA and 2-3-fold upregulation of STXBP1 protein in haploinsufficient neurons. Additionally, when applied to patient-derived excitatory cortical neurons AAV-STXBP1 rescued the aberrant electrophysiological phenotypes noted by multi-electrode array (MEA) analysis. Together we present new AAVs for robust transduction of iPSC derived neurons from patient cells, and show their utility for assessing efficacy of AAV-STXBP1 for STXBP1 haploinsufficiency disorders. (S.A. and E.W. contributed equally to this work).
Plain Language Summary
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Sakshi Arora1,2, Elisa A. Waxman1,2, Lea V. Dungan1,2, Deborah L. French1,2, Benjamin L. Prosser2,3, Beverly L. Davidson1,2
1Center for Cellular and Molecular Therapeutics (CCMT), Children's Hospital of Philadelphia, Philadelphia, PA,2Center for Epilepsy and Neuro Developmental Disorders (ENDD), The Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA,3Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA"
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