Selected Grantee Publications
Gap-Junction-Mediated Bioelectric Signaling Required for Slow Muscle Development and Function in Zebrafish
Lukowicz-Bedford et al., Current Biology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38936363
Using the neuromuscular system of embryonic zebrafish as a model, Lukowicz-Bedford et al. have identified a protein that is responsible for controlling bioelectric signaling in slow muscle development and function. Bioelectric signaling is a form of intercellular communication that has emerged as a key regulator of animal development. These signals can be mediated by gap junction channels—fast, direct pathways between cells for the movement of ions and other small molecules—that are formed in vertebrates by a highly conserved transmembrane protein family called connexins. However, the connexin gene family is large and complex, making it challenging to identify specific connexins that create channels within developing and mature tissues. This work reveals a molecular basis for gap-junction communication among developing muscle cells and shows how disruptions to bioelectric signaling in the neuromuscular system may contribute to developmental myopathies. Supported by ORIP (R24OD026591), NINDS, and NIGMS.
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.
RNA Landscapes of Brain and Brain-Derived Extracellular Vesicles in Simian Immunodeficiency Virus Infection and Central Nervous System Pathology
Huang et al., The Journal of Infectious Diseases. 2024.
https://pubmed.ncbi.nlm.nih.gov/38079216/
Brain tissue–derived extracellular vesicles (bdEVs) act locally in the central nervous system (CNS) and may indicate molecular mechanisms in HIV CNS pathology. Using brain homogenate (BH) and bdEVs from male pigtailed macaques, researchers identified dysregulated RNAs in acute and chronic infection. Most dysregulated messenger RNAs (mRNAs) in bdEVs reflected dysregulation in source BH, and these mRNAs are disproportionately involved in inflammation and immune responses. Additionally, several circular RNAs were differentially abundant in source tissue and might be responsible for specific differences in small RNA levels in bdEVs during simian immunodeficiency virus (SIV) infection. This RNA profiling shows potential regulatory networks in SIV infection and SIV-related CNS pathology. Supported by ORIP (U42OD013117), NCI, NIAID, NIDA, NIMH, and NINDS.
Genetic Diversity of 1,845 Rhesus Macaques Improves Genetic Variation Interpretation and Identifies Disease Models
Wang et al., Nature Communications. 2024.
https://www.nature.com/articles/s41467-024-49922-6
Nonhuman primates are ideal models for certain human diseases, including retinal and neurodevelopmental disorders. Using a reverse genetics approach, researchers profiled the genetic diversity of rhesus macaque populations across eight primate research centers in the United States and uncovered rhesus macaques carrying naturally occurring pathogenic mutations. They identified more than 47,000 single-nucleotide variants in 374 genes that had been previously linked with retinal and neurodevelopmental disorders in humans. These newly identified variants can be used to study human disease pathology and to test novel treatments. Supported by ORIP (P51OD011107, P51OD011106, P40OD012217, S10OD032189), NEI, NIAID, and NIMH.
Integrin αvβ3 Upregulation in Response to Nutrient Stress Promotes Lung Cancer Cell Metabolic Plasticity
Nam, Cancer Research. 2024.
https://pubmed.ncbi.nlm.nih.gov/38588407/
Tumor-initiating cells can survive in harsh environments via stress tolerance and metabolic flexibility; studies on this topic can yield new targets for cancer therapy. Using cultured cells and live human surgical biopsies of non-small cell lung cancer, researchers demonstrated that nutrient stress drives a metabolic reprogramming cascade that allows tumor cells to thrive despite a nutrient-limiting environment. This cascade results from upregulation of integrin αvβ3, a cancer stem cell marker. In mice, pharmacological or genetic targeting prevented lung cancer cells from evading the effects of nutrient stress, thus blocking tumor initiation. This work suggests that this molecular pathway leads to cancer stem cell reprogramming and could be linked to metabolic flexibility and tumor initiation. Supported by ORIP (K01OD030513), NCI, NIGMS, and NINDS.
Transcriptome- and Proteome-Wide Effects of a Circular RNA Encompassing Four Early Exons of the Spinal Muscular Atrophy Genes
Luo, Scientific Reports. 2024.
https://pubmed.ncbi.nlm.nih.gov/38714739/
Spinal muscular atrophy (SMA) is a leading genetic cause of mortality in infants and often results from a deficiency of deletions of or mutations in the SMN1 gene. In this study, researchers report the transcriptome- and proteome-wide effects of overexpression of C2A‑2B3-4, a circular RNA produced by SMN1 and SMN2, in cells. They report that C2A-2B-3-4 is associated with expression of genes associated with chromatin remodeling, transcription, spliceosome function, ribosome biogenesis, lipid metabolism, cytoskeletal formation, cell proliferation, and neuromuscular junction formation. More work is needed to investigate the role of these genes in processes associated with SMA and other pathological conditions, including cancer and male infertility. Supported by ORIP (T35OD027967) and NINDS.
Neutralizing Antibody Response to SARS‐CoV‐2 Bivalent mRNA Vaccine in SIV‐Infected Rhesus Macaques: Enhanced Immunity to XBB Subvariants by Two‐Dose Vaccination
Faraone, Journal of Medical Virology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38528837/
Researchers have shown that mRNA vaccination is less effective for people with advanced or untreated HIV infection, but data on the efficacy of mRNA vaccination against SARS-CoV-2 in this population are limited. Using rhesus macaques (sex not specified) with simian immunodeficiency virus (SIV), investigators examined the neutralizing antibody (nAb) response to SARS-CoV-2 vaccination. They found that administration of the bivalent vaccine alone can generate robust nAb titers against Omicron subvariants. Additionally, dams that received antiretroviral therapy had lower nAb titers than untreated dams. Overall, these findings highlight the need for further investigations into the nAb response in people with HIV. Supported by ORIP (P51OD011104), NCI, NIAID, NICHD, and NIMH.
Cdk8/CDK19 Promotes Mitochondrial Fission Through Drp1 Phosphorylation and Can Phenotypically Suppress Pink1 Deficiency in Drosophila
Liao et al., Nature Communications. 2024.
https://www.nature.com/articles/s41467-024-47623-8
Pink1 is a mitochondrial kinase implicated in Parkinson’s disease and is conserved among humans, rodents, and flies. In this study, researchers found that Cdk8 in Drosophila (i.e., the orthologue of vertebrate CDK8 and CDK19) promotes the phosphorylation of Drp1 (i.e., a protein required for mitochondrial fission) at the same residue as Pink1. Cdk8 is expressed in both the cytoplasm and nucleus, and neuronal loss of Cdk8 reduces fly life span and causes bang sensitivity and elongated mitochondria in both muscles and neurons. Overexpression of Cdk8 suppresses elevated levels of reactive oxygen species, mitochondrial dysmorphology, and behavioral defects in flies with low levels of Pink1. These findings suggest that Cdk8 regulates Drp1-mediated mitochondrial fission in a similar manner as Pink1 and may contribute to the development of Parkinson’s disease. Supported by ORIP (R24OD022005, R24OD031447, P40OD018537, P40OD010949), NICHD, and NINDS.
Molecular Basis of Human Trace Amine-Associated Receptor 1 Activation
Zilberg et al., Nature Communications. 2024.
https://www.nature.com/articles/s41467-023-44601-4
The authors reported the cryogenic electron microscopy structure of human trace amine-associated receptor 1 (hTAAR1, hTA1) signaling complex, a key modulator in monoaminergic neurotransmission, as well as its similarities and differences with other TAAR members and rodent TA1 receptors. This discovery has elucidated hTA1’s molecular mechanisms underlining the strongly divergent pharmacological properties of human and rodent TA1 and therefore will boost the translation of preclinical studies to clinical applications in treating disorders of dopaminergic dysfunction, metabolic disorders, cognitive impairment, and sleep-related dysfunction. Supported by ORIP (S10OD019994, S10OD026880, and S10OD030463), NIDA, NIGMS, NIMH, and NCATS.