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Animal Models

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Selected Grantee Publications

Impaired Axon Initial Segment Structure and Function in a Model of ARHGEF9 Developmental and Epileptic Encephalopathy

Wang et al., PNAS. 2024.

https://www.pnas.org/doi/10.1073/pnas.2400709121

Researchers developed a mouse model carrying the G55A missense variant identified in ARHGEF9 patients with severe epilepsy and neurodevelopmental phenotypes. Using male Arhgef9G55A mice, this study examined behavioral, molecular, and electrophysiological phenotypes in the Arhgef9G55A model of developmental and epileptic encephalopathies (DEE). Researchers found that the G55A variant causes disruption of inhibitory postsynaptic organization and axon initial segment (AIS) architecture, leading to impairment of both synaptic transmission and action potential generation. The effects of Arhgef9G55A on neuronal function affect both intrinsic and synaptic excitability and preferentially impair AIS. These findings indicate a novel pathological mechanism of DEE and represent a unique example of a neuropathological condition converging from AIS dysfunctions. Supported by ORIP (U54OD020351, U54OD030187, U54OD020351, S10OD026974) and NINDS.

Systematic Multi-trait AAV Capsid Engineering for Efficient Gene Delivery

Eid et al., Nature Communications. 2024.

https://doi.org/10.1038/s41467-024-50555-y

Engineering novel functions into proteins while retaining desired traits is a key challenge for developers of viral vectors, antibodies, and inhibitors of medical and industrial value. In this study, investigators developed Fit4Function, a generalizable machine learning (ML) approach for systematically engineering multi-trait adeno-associated virus (AAV) capsids. Fit4Function was used to generate reproducible screening data from a capsid library that samples the entire manufacturable sequence space. The Fit4Function data were used to train accurate sequence-to-function models, which were combined to develop a library of capsid candidates. Compared to AAV9, top candidates from the Fit4Function capsid library exhibited comparable production yields; more efficient murine liver transduction; up to 1,000-fold greater human hepatocyte transduction; and increased enrichment in a screen for liver transduction in macaques. The Fit4Function strategy enables prediction of peptide-modified AAV capsid traits across species and is a critical step toward assembling an ML atlas that predicts AAV capsid performance across dozens of traits. Supported by ORIP (P51OD011107, U42OD027094), NIDDK, NIMH, and NINDS.

Intrinsic Link Between PGRN and GBA1 D409V Mutation Dosage in Potentiating Gaucher Disease

Lin et al., Human Molecular Genetics. 2024.

https://doi.org/10.1093/hmg/ddae113

Gaucher disease (GD) is an autosomal recessive disorder and one of the most common lysosomal storage diseases. GD is caused by mutations in the GBA1 gene that encodes glucocerebrosidase (GCase), a lysosomal protein involved in glyocolipid metabolism. Progranulin (PGRN, encoded by GRN) is a modifier of GCase, and GRN mutant mice exhibit a GD-like phenotype. The researchers in this study aimed to understand the relationship between GCase and PGRN. They generated a panel of mice with various doses of the GBA1 D409V mutation in the GRN-/- background and characterized the animals’ disease progression using biochemical, pathological, transcriptomic, and neurobehavioral analyses. Homozygous (GRN-/-, GBA1 D409V/D409V) and hemizygous (GRN-/-, GBA1 D409V/null) animals exhibited profound inflammation and neurodegeneration compared to PG96 wild-type mice. Compared to homozygous mice, hemizygous mice showed more profound phenotypes (e.g., earlier onset, increased tissue fibrosis, shorter life span). These findings offer insights into GD pathogenesis and indicate that GD severity is affected by GBA1 D409V dosage and the presence of PGRN. Supported by ORIP (R21OD033660) and NINDS.

PIKFYVE Inhibition Mitigates Disease in Models of Diverse Forms of ALS

Hung et al., Cell . 2023.

https://doi.org/10.1016/j.cell.2023.01.005

Investigators showed that pharmacological suppression of PIKFYVE activity reduces pathology and extends survival of animal models and patient-derived motor neurons representing diverse forms of amyotrophic lateral sclerosis (ALS). Upon PIKFYVE inhibition, exocytosis is activated to transport aggregation-prone proteins out of the cells, a process that does not require stimulating macroautophagy or the ubiquitin-proteosome system. These findings suggest therapeutic potential to manage multiple forms of ALS. Supported by ORIP (S10OD021553) and NINDS.