Biology subjects

Felix, A. J.

Publications and source records attributed to Felix, A. J..

2 recordsLinked to original sources

bioRxiv2024

Generation of humanized mouse models to support therapeutic development for SYNGAP1 and STXBP1 disorders

Heterozygous variants in SYNGAP1 and STXBP1 cause distinct neurodevelopmental disorders due to haploinsufficiency of essential synaptic proteins. As gene targeted approaches to correct these disorders often target non-conserved genomic regions, thus limiting their clinical translation, we generated humanized mouse models wherein the entire Syngap1 or Stxbp1 loci were replaced with their human counterparts. Stxbp1 humanized mice exhibited impaired viability, while Stxbp1 hybrid mice (Stxbp1Hu/+) were viable and suitable for evaluating target engagement of human-specific therapeutics. Syngap1 humanized mice were viable and successfully crossed with Syngap1 heterozygous mice to produce a Syngap1 humanized-haploinsufficient model (Syngap1Hu/-). Syngap1Hu/- mice displayed haploinsufficient levels of human SYNGAP1, disease-relevant behaviors, and EEG abnormalities including epileptiform activity and generalized slowing. Importantly, parallel analysis in a cohort of patients with SYNGAP1-disorder revealed similar electrophysiological signatures. Finally, we showed that human gene-targeted antisense oligonucleotides modulate human SYNGAP1 expression in Syngap1Hu/- neurons. Together, we describe new models to support pre-clinical therapeutic development for SYNGAP1 and STXBP1 disorders and identify translational biomarkers of SYNGAP1-disorder in mice and humans to benchmark therapeutic testing.

neuroscience↗

bioRxiv2022

Mapping PTBP splicing in human brain identifies targets for therapeutic splice switching including SYNGAP1

Alternative splicing of neuronal genes is controlled in part by the coordinated action of the polypyrimidine tract binding proteins (PTBP1 and PTBP2). While PTBP1 is ubiquitously expressed, PTBP2 is predominantly neuronal, controlling the expression of such targets as DLG4, which encodes PSD95, a protein important in synaptic function whose deficiency causes neurodevelopmental disorders. Here, we fully define the PTBP2 footprint in the human transcriptome using both human brain tissue and neurons derived from human induced pluripotent stem cells (iPSC-neurons). We identify direct PTBP2 binding sites and define PTBP2-dependent alternative splicing events, finding novel targets such as STXBP1 and SYNGAP1, which are synaptic genes also associated with neurodevelopmental disorders. The resultant PTBP2 binding and splicing maps were used to test if PTBP2 binding could be manipulated to increase gene expression in PTBP-targeted genes that cause disease when haploinsufficient. We find that PTBP2 binding to SYNGAP1 mRNA promotes alternative splicing and non-sense mediated decay. Antisense oligonucleotides that disrupt PTBP binding sites on SYNGAP1 redirect splicing and increase gene and protein expression. Collectively, our data provide a comprehensive view of PTBP2-dependent alternative splicing in human neurons and human cerebral cortex, guiding the development of novel therapeutic tools that may benefit a range of neurodevelopmental disorders.

molecular biology↗