Selected Grantee Publications
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.
Canine Models of Charcot-Marie-Tooth: MTMR2, MPZ, and SH3TC2 Variants in Golden Retrievers With Congenital Hypomyelinating Polyneuropathy
Cook et al., Neuromuscular Disorders. 2023.
https://pubmed.ncbi.nlm.nih.gov/37400349/
Both demyelination and hypomyelination of the nervous system are associated with various clinical diseases. Using whole-genome sequencing, researchers determined the genetic underpinnings of congenital hypomyelinating polyneuropathy in canines of both sexes. These variants genetically describe the first peripheral nervous system–exclusive hypomyelinating polyneuropathies in dogs. By testing for these mutations, breeders can prevent the production of affected offspring. Supported by ORIP (K01OD027051, K01OD027058).
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.
Proteomic Profiling of Extracellular Vesicles Isolated From Plasma and Peritoneal Exudate in Mice Induced by Crotalus scutulatus scutulatus Crude Venom and Its Purified Cysteine-Rich Secretory Protein (Css-CRiSP)
Reyes et al., Toxins (Basel). 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10467150/
Toxins in viperid snakes can induce clinically heterogeneous effects, but most viper venoms are composed of only 10 main protein families. Researchers investigated the proteome expression profile of extracellular vesicles isolated from biofluid samples from male and female mice after injection with crude venom and cysteine-rich secretory proteins. They reported changes in the expression of proteins involved in cell adhesion, cytoskeleton rearrangement, signal transduction, immune responses, and vesicle-mediated transports. This work could be applied in future efforts for early detection and assessment of local effects. Supported by ORIP (P40OD010960), NIGMS, and NHLBI.
Photoreceptor Disc Incisures Form as an Adaptive Mechanism Ensuring the Completion of Disc Enclosure
Lewis et al., eLife. 2023.
https://elifesciences.org/articles/89160
The first steps of vision take place within a stack of tightly packed disc-shaped membranes, or discs, located in the outer segment compartment of photoreceptor cells. In rod photoreceptors, discs are enclosed inside the outer segment and contain deep indentations in their rims called incisures. This presence of incisures has been documented in several species, yet their role remains elusive. This study demonstrated that incisures are formed only after discs become completely enclosed. At the earliest stage of their formation, discs are not round but rather are highly irregular in shape and resemble expanding lamellipodia. In genetically modified mice and frogs, researchers measuring outer segment protein abundances found that incisure size is determined by the molar ratio between peripherin-2, a disc rim protein critical for the process of disc enclosure, and rhodopsin, the major structural component of disc membranes. High perpherin-2-to-rhodopsin ratio causes an increase in incisure size and structural complexity; low ratio precludes incisure formation. They propose a model whereby normal rods express a modest excess of peripherin-2 over the amount required for complete disc enclosure to ensure that this important step of disc formation is accomplished. Once the disc is enclosed, the excess peripherin-2 incorporates into the rim to form an incisure. Supported by ORIP (P40OD010997, R24OD030008).
Allogeneic Immunity Clears Latent Virus Following Allogeneic Stem Cell Transplantation in SIV-Infected ART-Suppressed Macaques
Wu et al., Immunity. 2023.
https://doi.org/10.1016/j.immuni.2023.04.019
Allogeneic hematopoietic stem cell transplantation (alloHSCT) has been documented as curative for HIV, but the mechanisms are not yet known. Using Mauritian cynomolgus macaques of both sexes, researchers performed reduced-intensity alloHSCT experiments to define the individual contributions of allogeneic immunity and CCR5 deficiency to an alloHSCT-mediated HIV cure. They reported that allogeneic immunity was the major driver of reservoir clearance, mediating graft-versus-reservoir effects in HIV infection. Their results also point to a protective mechanism for CCR5 deficiency early during engraftment. Future efforts could focus on harnessing the beneficial effects of allogeneic immunity while avoiding graft-versus-host disease. Supported by ORIP (P51OD011092) and NIAID.
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.
Epigenetic Dysregulation From Chromosomal Transit in Micronuclei
Agustinus et al., Nature . 2023.
https://www.nature.com/articles/s41586-023-06084-7
The authors reported a mechanistic link between epigenetic alterations and chromosomal instability induced during their transit in micronuclei, both being hallmarks of advanced and metastatic cancers. It was demonstrated that the landscape of histone post-translational modifications was profoundly changed due to missegregation of mitotic chromosomes, their sequestration in micronuclei and subsequent rupture of the micronuclear envelope. The transcriptional redistribution was attributed to micronuclei’s strong positional bias with increased promoter accessibility. The continuous formation and reincorporation of micronuclei promotes epigenetic reprogramming and heterogeneity in cancer. Supported by ORIP (S10OD030286) and others.