Selected Grantee Publications
Body Stiffness Is a Mechanical Property That Facilitates Contact-Mediated Mate Recognition in Caenorhabditis elegans
Weng et al., Current Biology. 2023.
https://www.sciencedirect.com/science/article/abs/pii/S0960982223009272
Body stiffness is a mechanical property that facilitates contact-mediated mate recognition in Caenorhabditis elegans. Chemical cues have been extensively studied as sensory cures of mate recognition, whereas the role of mechanical cues is largely unknown. Investigators studied the link of the hypodermis and body stiffness with mate recognition and mating efficiency in the worm C. elegans. They found that worm males assess attractiveness of potential mates though contact-mediated cues determined by species, sex, and developmental stages of the hypodermis. Body stiffness maintained by a group of cuticular collagens is critical for mate recognition and mating efficiency. This study suggests the important role of mechanosensory cues in mate recognition and provides a platform for mechanistically studying social behavior. Supported by ORIP (R24OD023041, P40OD010440) and NINDS.
A Defect in Mitochondrial Fatty Acid Synthesis Impairs Iron Metabolism and Causes Elevated Ceramide Levels
Dutta et al., Nature Metabolism. 2023.
https://pubmed.ncbi.nlm.nih.gov/37653044/
Human mitochondrial enoyl coenzyme A reductase (Mecr), required for the last step of mitochondrial fatty acid synthesis (mtFAS), is linked to pediatric-onset neurodegeneration, but with unknown mechanisms. Researchers investigated phenotypes of mecr mutants in Drosophila and human-derived fibroblasts. They found that loss of function of Mecr in the whole body resulted in a defect in Fe-S cluster biogenesis and increased iron levels, leading to elevated ceramide levels and lethality in flies. Similar elevated ceramide levels and impaired iron homeostasis were observed human-derived fibroblasts with Mecr deficiency. Neuronal loss of Mecr led to progressive neurodegeneration in flies. This study pointed out a mechanistic link between mtFAS and neurodegeneration through Mecr. Supported by ORIP (R24OD022005, R24OD031447), NICHD, and NINDS.
The Latent Reservoir of Inducible, Infectious HIV-1 Does Not Decrease Despite Decades of Antiretroviral Therapy
McMyn et al., The Journal of Clinical Investigation. 2023.
https://www.doi.org/10.1172/JCI171554
Antiretroviral therapy (ART) does not eliminate the latent HIV reservoir, but it is unknown whether sustained reservoir decay occurs with long-term ART. Researchers used a quantitative viral outgrowth assay, an intact proviral DNA assay, and proviral sequencing to characterize the latent reservoir in men and women with HIV who had maintained suppression of viral replication on ART for 14 to 27 years. They found that the reservoir decay did not continue with long-term ART. Further studies could provide insight into the mechanism underlying these findings. These results reinforce the need for lifelong ART and indicate that the reservoir remains a major barrier to an HIV-1 cure. Supported by ORIP (R01OD011095), NIAID, and NIDCR.
Antiretroviral Therapy Ameliorates Simian Immunodeficiency Virus–Associated Myocardial Inflammation by Dampening Interferon Signaling and Pathogen Response in the Heart
Robinson et al., The Journal of Infectious Diseases. 2023.
https://doi.org/10.1093/infdis/jiad105
HIV is associated with increased risk of cardiovascular disease, but the underlying mechanisms are not fully understood. Using RNA sequencing, investigators characterized the effects of simian immunodeficiency virus (SIV) infection on the hearts of male rhesus macaques. They demonstrated that SIV infection drives a canonical antiviral response in the heart, as well as dysregulation of genes involved in fatty acid shuttling and metabolism. Their findings suggest that antiretroviral therapy helps mitigate immune activation during viremic conditions and plays a cardioprotective role. Future studies are needed to assess the long-term effects of these dynamics. Supported by ORIP (P51OD011104), NIAID, NIMH, and NINDS.
Focused Ultrasound–Mediated Brain Genome Editing
Lao et al., PNAS. 2023.
https://www.pnas.org/doi/epdf/10.1073/pnas.2302910120
Gene editing in the brain has been challenging because of the restricted transport imposed by the blood–brain barrier (BBB). In this study, investigators described a safe and effective gene‑editing technique by using focused ultrasound (FUS) to transiently open the BBB for the transport of intravenously delivered CRISPR machinery to the brain in mice. By combining FUS with adeno-associated virus–mediated gene delivery, researchers can achieve more than 25% editing efficiency of particular cell types. This method has the potential to expand toolkit options for CRISPR delivery and opens opportunities for treating diseases of the brain, such as neurodegenerative disorders, with somatic genome editing. Supported by ORIP (U42OD026635) and NINDS.
Diverse Targets of SMN2-Directed Splicing-Modulating Small Molecule Therapeutics for Spinal Muscular Atrophy
Ottesen et al., Nucleic Acids Research. 2023.
https://academic.oup.com/nar/article/51/12/5948/7110763?login=true
Spinal muscular atrophy (SMA) results from deletions or mutations of the SMN1 gene. SMN2 is a nearly identical copy of SMN1 but cannot compensate for its loss. Manipulation of splicing to restore SMN2 exon 7 inclusion provides a promising therapeutic avenue for SMA, and two small-molecule agents—risdiplam and branaplam—restore body-wide inclusion of the SMN2 exon 7 upon oral administration. In this study, researchers demonstrate the advantages of combined treatments with low doses of risdiplam and branaplam. These findings can be applied to develop the next generation of small‑molecule therapeutics, with a focus on better efficacies and fewer off-target effects. Supported by ORIP (T35OD027967) and NINDS.
SALL1 Enforces Microglia-Specific DNA Binding and Function of SMADs to Establish Microglia Identity
Fixsen et al., Nature Immunology. 2023.
https://doi.org/10.1038/s41590-023-01528-8
Microglia function is thought to play a role in neurodevelopmental, psychiatric, and neurodegenerative diseases. Using knockout mice, investigators explored functional interactions between spalt-like transcription factor 1 (SALL1) and SMAD4, which demonstrated that interactions are mediated by a conserved microglia-specific SALL1 super-enhancer and result in direct activation of regulatory elements. The concerted interactions induce a microglia lineage determining program of gene expression. These findings indicate that expression of SALL1 and associated genes could contribute to phenotypes of aging and neurodegenerative diseases. Supported by ORIP (S10OD026929), NIA, NIMH, and NINDS.
A Comprehensive Drosophila Resource to Identify Key Functional Interactions Between SARS-CoV-2 Factors and Host Proteins
Guichard et al., Cell Reports. 2023.
https://pubmed.ncbi.nlm.nih.gov/37480566/
To address how interactions between SARS-CoV-2 factors and host proteins affect COVID-19 symptoms, including long COVID, and facilitate developing effective therapies against SARS-CoV-2 infections, researchers reported the generation of a comprehensive set of resources, mainly genetic stocks and a human cDNA library, for studying viral–host interactions in Drosophila. Researchers further demonstrated the utility of these resources and showed that the interaction between NSP8, a SARS-CoV-2 factor, and ATE1 arginyltransferase, a host factor, causes actin arginylation and cytoskeleton disorganization, which may be relevant to several pathogenesis processes (e.g., coagulation, cardiac inflammation, fibrosis, neural damage). Supported by ORIP (R24OD028242, R24OD022005, R24OD031447), NIAID, NICHD, NIGMS, and NINDS.
Osteopontin Is an Integral Mediator of Cardiac Interstitial Fibrosis in Models of Human Immunodeficiency Virus Infection
Robinson et al., The Journal of Infectious Diseases. 2023.
https://www.doi.org/10.1093/infdis/jiad149
HIV infection is associated with increased risk of cardiovascular disease. Plasma osteopontin (Opn) is correlated with cardiac pathology, but more work is needed to understand the underlying mechanisms driving cardiac fibrosis. Researchers explored this topic using mouse embryonic fibroblasts, male macaques, and humanized mice of both sexes. They reported the accumulation of Opn in the heart with simian immunodeficiency virus infection. Systemic inhibition of Opn can prevent HIV-associated interstitial fibrosis in the left ventricle. These findings suggest that Opn could be a potential target for adjunctive therapies to reduce cardiac fibrosis in people with HIV. Supported by ORIP (P51OD011104), NIAID, NHLBI, NIMH, and NINDS.
GluN2B Inhibition Confers Resilience against Long-Term Cocaine-Induced Neurocognitive Sequelae
Li et al., Neuropsychopharmacology. 2023.
https://www.nature.com/articles/s41386-022-01437-8
Cocaine self-administration can disrupt the capacity of humans and rodents to flexibly modify familiar behavioral routines, but effects on mechanistic factors—particularly those driving long-term behavioral changes—have not been characterized fully. Researchers used mice to examine the flexibility of decision-making behavior with oral cocaine self-administration. They found that GluN2B inhibition prevented cocaine-induced dysregulation of neuronal structure and function in the orbitofrontal cortex (OFC), preserving mature, mushroom-shaped dendritic spine densities on deep-layer pyramidal neurons. These findings suggest that cocaine potentiates GluN2B-dependent signaling, which triggers a series of durable adaptations that result in the dysregulation of post-synaptic neuronal structure in the OFC, ultimately weakening the capacity for flexible choice. Supported by ORIP (P51OD011132) and NINDS.