Selected Grantee Publications
AAV Capsid Variants with Brain-Wide Transgene Expression and Decreased Liver Targeting After Intravenous Delivery in Mouse and Marmoset
Goertsen et al., Nature Neuroscience. 2021.
https://www.nature.com/articles/s41593-021-00969-4
Genetic intervention is increasingly being explored as a therapeutic option for debilitating disorders of the central nervous system (CNS). This project focused on organ-specific targeting of adeno-associated virus (AAV) capsids after intravenous delivery. These results constitute an important step forward toward achieving the goal of engineered AAV vectors that can be used to broadly deliver gene therapies to the CNS in humans. Supported by ORIP (U24OD026638), NIMH, and NINDS.
Precise Visuomotor Transformations Underlying Collective Behavior in Larval Zebrafish
Harpaz et al., Nature Communications. 2021.
https://www.nature.com/articles/s41467-021-26748-0
Sensory signals from neighbors, analyzed in the visuomotor stream of animals, is poorly understood. The authors studied aggregation behavior in larval zebrafish and found that over development larvae transition from over dispersed groups to tight shoals. Young larvae turn away from virtual neighbors by integrating and averaging retina-wide visual occupancy within each eye, and by using a winner-take-all strategy for binocular integration. Observed algorithms accurately predict group structure over development. These findings allow testable predictions regarding the neuronal circuits underlying collective behavior in zebrafish. Supported by ORIP (R43OD024879, R44OD024879) and NINDS.
Negative Inotropic Mechanisms of β-cardiotoxin in Cardiomyocytes by Depression of Myofilament ATPase Activity without Activation of the Classical β-Adrenergic Pathway
Lertwanakarn et al., Scientific Reports. 2021.
https://www.nature.com/articles/s41598-021-00282-x
Beta-cardiotoxin (β-CTX) from the king cobra venom (Ophiophagus hannah) was previously proposed as a novel β-adrenergic blocker. However, the involvement of β-adrenergic signaling by this compound has never been elucidated. The objectives of this study were to investigate the underlying mechanisms of β-CTX as a β-blocker and its association with the β-adrenergic pathway. Healthy Sprague Dawley rats were used for cardiomyocytes isolation. In summary, the negative inotropic mechanism of β-CTX was discovered. β-CTX exhibits an atypical β-blocker mechanism. These properties of β-CTX may benefit in developing a novel agent aid to treat hypertrophic cardiomyopathy. Supported by ORIP (P40OD010960) and NHLBI.
Collective Behavior Emerges from Genetically Controlled Simple Behavioral Motifs in Zebrafish
Harpaz et al., Science Advances. 2021.
https://www.science.org/doi/10.1126/sciadv.abi7460
Harpaz et al. report that zebrafish regulate their proximity and alignment with each other at early larval stages. Two visual responses (one measuring relative visual field occupancy and one accounting for global visual motion), account for emerging group behavior. Mutations in genes known to affect social behavior in humans perturb these reflexes in individual larval zebrafish and change their emergent collective behaviors. Model simulations show that changes in these two responses in individual mutant animals predict well the distinctive collective patterns that emerge in a group. Hence, group behaviors reflect in part genetically defined primitive sensorimotor “motifs” evident in young larvae. Supported by ORIP (R43OD024879, R44OD024879) and NINDS.
Comparative Cellular Analysis of Motor Cortex in Human, Marmoset and Mouse
Bakken et al., Nature. 2021.
https://pubmed.ncbi.nlm.nih.gov/34616062/
Investigators used high-throughput transcriptomic and epigenomic profiling of more than 450,000 single nuclei in humans, marmosets, and mice, to characterize the cellular makeup of the primary motor cortex (M1), which exhibits similarities that mirror evolutionary distance and are consistent between the transcriptome and epigenome. Despite the overall conservation, many species-dependent specializations are apparent. These results demonstrate the robust molecular foundations of cell-type diversity in M1 across mammals and point to the genes and regulatory pathways responsible for the functional identity of cell types and their species-specific adaptations. Supported by ORIP (P51OD010425), NIMH, NCATS, NINDS, and NIDA.
A Novel Non-Human Primate Model of Pelizaeus-Merzbacher Disease
Sherman et al., Neurobiology of Disease. 2021.
https://www.sciencedirect.com/science/article/pii/S096999612100214X
Pelizaeus-Merzbacher disease (PMD) in humans is a severe hypomyelinating disorder of the central nervous system (CNS) linked to mutations in the proteolipid protein-1 (PLP1) gene. Investigators report on three spontaneous cases of male neonatal rhesus macaques (RMs) with clinical symptoms of hypomyelinating disease. Genetic analysis revealed that the parents of these related RMs carried a rare, hemizygous missense variant in exon 5 of the PLP1 gene. These RMs represent the first reported NHP model of PMD, providing an opportunity for studies to promote myelination in pediatric hypomyelinating diseases, as other animal models for PMD do not fully mimic the human disorder. Supported by ORIP (R24OD021324, P51OD011092, and S10OD025002) and NINDS.
MIC-Drop: A Platform for Large-scale In Vivo CRISPR Screens
Parvez et al., Science. 2021.
https://pubmed.ncbi.nlm.nih.gov/34413171/
CRISPR screens in animals are challenging because generating, validating, and keeping track of large numbers of mutant animals is prohibitive. These authors introduce Multiplexed Intermixed CRISPR Droplets (MIC-Drop), a platform combining droplet microfluidics, single-needle en masse CRISPR ribonucleoprotein injections, and DNA barcoding to enable large-scale functional genetic screens in zebrafish. In one application, they showed that MIC-Drop could identify small-molecule targets. Furthermore, in a MIC-Drop screen of 188 poorly characterized genes, they discovered several genes important for cardiac development and function. With the potential to scale to thousands of genes, MIC-Drop enables genome-scale reverse genetic screens in model organisms. Supported by ORIP (R24OD017870), NIGMS, and NHLBI.
Factor XII Plays a Pathogenic Role in Organ Failure and Death in Baboons Challenged with Staphylococcus aureus
Silasi et al., Blood. 2021.
https://pubmed.ncbi.nlm.nih.gov/33598692/
Activation of coagulation factor (F) XI promotes multiorgan failure in rodent models of sepsis and in a baboon model for lethal systemic inflammation induced by infusion of heat-inactivated Staphylococcus aureus. The authors used the anticoagulant FXII-neutralizing antibody 5C12 to verify the mechanistic role of FXII. Inhibition of FXII prevented fever, terminal hypotension, respiratory distress, and multiorgan failure. All animals receiving 5C12 had milder and transient clinical symptoms; untreated control animals suffered irreversible multiorgan failure. This study confirms their previous finding that at least two enzymes of FXIa and FXIIa play critical roles in the development of an acute and terminal inflammatory response. Supported by ORIP (P40OD024628), NIAID, NHLBI, and NIGMS.
Innate Immunity Stimulation via CpG Oligodeoxynucleotides Ameliorates Alzheimer’s Disease Pathology in Aged Squirrel Monkeys
Patel et al., Brain: A Journal of Neurology. 2021.
https://pubmed.ncbi.nlm.nih.gov/34128045/
Alzheimer's disease is the only illness among the top 10 causes of death for which there is no disease-modifying therapy. The authors have shown in transgenic Alzheimer's disease mouse models that harnessing innate immunity via TLR9 agonist CpG oligodeoxynucleotides (ODNs) modulates age-related defects associated with immune cells and safely reduces amyloid plaques, oligomeric amyloid-β, tau pathology, and cerebral amyloid angiopathy (CAA). They used a nonhuman primate model for sporadic Alzheimer's disease pathology that develops extensive CAA-elderly squirrel monkeys. They demonstrate that long-term use of Class B CpG ODN 2006 induces a favorable degree of innate immunity stimulation. CpG ODN 2006 has been well established in numerous human trials for a variety of diseases. This evidence together with their earlier research validates the beneficial therapeutic outcomes and safety of this innovative immunomodulatory approach. Supported by ORIP (P40OD010938), NINDS, NIA, and NCI.
Loss of Gap Junction Delta-2 (GJD2) Gene Orthologs Leads to Refractive Error in Zebrafish
Quint et al., Communications Biology. 2021.
https://pubmed.ncbi.nlm.nih.gov/34083742/
Myopia is the most common developmental disorder of juvenile eyes. Although little is known about the functional role of GJD2 in refractive error development, the authors find that depletion of gjd2a (Cx35.5) or gjd2b (Cx35.1) orthologs in zebrafish cause changes in eye biometry and refractive status. Their immunohistological and scRNA sequencing studies show that Cx35.5 (gjd2a) is a retinal connexin; its depletion leads to hyperopia and electrophysiological retina changes. They found a lenticular role; lack of Cx35.1 (gjd2b) led to a nuclear cataract that triggered axial elongation. The results provide functional evidence of a link between gjd2 and refractive error. Supported by ORIP (R24OD026591), NIGMS, and NINDS.