Selected Grantee Publications
Cell-Specific Regulation of Gene Expression Using Splicing-Dependent Frameshifting
Ling et al., Nature Communications. 2022.
https://www.doi.org/10.1038/s41467-022-33523-2
Precise and reliable cell-specific gene delivery remains technically challenging. Investigators report a splicing-based approach for controlling gene expression whereby separate translational reading frames are coupled to the inclusion or exclusion of mutated, frameshifting cell-specific alternative exons. Candidate exons are identified by analyzing thousands of publicly available RNA sequencing datasets and filtering by cell specificity, conservation, and local intron length. This method, which they denote as splicing-linked expression design (SLED), can be combined in a Boolean manner with such existing techniques as minipromoters and viral capsids. SLED can use strong constitutive promoters, without sacrificing precision, by decoupling the tradeoff between promoter strength and selectivity. AAV-packaged SLED vectors can selectively deliver fluorescent reporters and calcium indicators to various neuronal subtypes in vivo. The authors also demonstrate gene therapy utility by creating SLED vectors that can target PRPH2 and SF3B1 mutations. The flexibility of SLED technology enables creative avenues for basic and translational research. Supported by ORIP (T32OD011089, S10OD026859), NEI, and NIMH.
Maternal Western-Style Diet Reduces Social Engagement and Increases Idiosyncratic Behavior in Japanese Macaque Offspring
Mitchell et al., Brain, Behavior, and Immunity. 2022.
https://www.doi.org/10.1016/j.bbi.2022.07.004
Evidence points to an association between maternal obesity and risk of early-emerging neurodevelopmental disorders in offspring, yet few preclinical studies have tested for associations between maternal Western-style diet (mWSD) and offspring behavior. Using Japanese macaques, researchers found that mWSD offspring exhibited less proximity to peers and initiated fewer affiliative social behaviors. These outcomes appear to be mediated by increased maternal interleukin-12 during the third trimester of pregnancy. Additionally, mWSD offspring displayed increased idiosyncratic behavior, which was related to alterations in maternal adiposity and leptin. These findings suggest specific prevention and intervention targets for early-emerging neurodevelopmental disorder in humans. Supported by ORIP (P51OD011092), NIMH, and NICHD.
De Novo Variants in EMC1 Lead to Neurodevelopmental Delay and Cerebellar Degeneration and Affect Glial Function in Drosophila
Chung et al., Human Molecular Genetics. 2022.
https://www.doi.org/10.1093/hmg/ddac053
Variants in EMC1, which encodes a subunit of the endoplasmic reticulum (ER)–membrane protein complex (EMC), are associated with developmental delay in children. Functional consequences of these variants are poorly understood. The investigators identified de novo variants in EMC1 in three children affected by global developmental delay, hypotonia, seizures, visual impairment, and cerebellar atrophy. They demonstrated in Drosophila that these variants are loss-of-function alleles and lead to lethality when expressed in glia but not in neurons. This work suggests the causality of EMC variants in disease. Supported by ORIP (R24OD022005, R24OD031447), NINDS, and NICHD.
Profiling Development of Abdominal Organs in the Pig
Gabriel et al., Scientific Reports. 2022.
https://www.doi.org/10.1038/s41598-022-19960-5
The pig is a model system for studying human development and disease due to its similarities to human anatomy, physiology, size, and genome. Moreover, advances in CRISPR gene editing have made genetically engineered pigs a viable model for the study of human pathologies and congenital anomalies. However, a detailed atlas illustrating pig development is necessary for identifying and modeling developmental defects. Here, the authors describe normal development of the pig abdominal system (i.e., kidney, liver, pancreas, spleen, adrenal glands, bowel, gonads) and compare them with congenital defects that can arise in gene-edited SAP130 mutant pigs. This atlas and the methods described here can be used as tools for identifying developmental pathologies of the abdominal organs in the pig at different stages of development. Supported by ORIP (U42OD011140), NHLBI, NIAID, NIBIB, NICHD, and NINDS.
Molecular and Cellular Evolution of the Primate Dorsolateral Prefrontal Cortex
Ma et al., Science. 2022.
https://www.doi.org/10.1126/science.abo7257
The dorsolateral prefrontal cortex (dlPFC) exists only in primates, lies at the center of high-order cognition, and is a locus of pathology underlying many neuropsychiatric diseases. The investigators generated single-nucleus transcriptome data profiling more than 600,000 nuclei from the dlPFC of adult humans, chimpanzees, rhesus macaques, and common marmosets of both sexes. Postmortem human samples were obtained from tissue donors. The investigators’ analyses delineated dlPFC cell-type homology and transcriptomic conservation across species and identified species divergence at the molecular and cellular levels, as well as potential epigenomic mechanisms underlying these differences. Expression patterns of more than 900 genes associated with brain disorders revealed a variety of conserved, divergent, and group-specific patterns. The resulting data resource will help to vertically integrate marmoset and macaque models with human-focused efforts to develop treatments for neuropsychiatric conditions. Supported by ORIP (P51OD011133), NIA, NICHD, NIDA, NIGMS, NHGRI, NIMH, and NINDS.
X Chromosome Agents of Sexual Differentiation
Arnold et al., Nature Reviews Endocrinology. 2022.
https://www.doi.org/10.1038/s41574-022-00697-0
Many diseases affect one sex disproportionately. A major goal of biomedical research is to understand which sex-biasing factors influence disease severity and to develop therapeutic strategies to target these factors. Two groups of such agents are sex chromosome genes and gonadal hormones. Researchers use the “four core genotypes” model to enable comparisons among animals with different sex chromosomes but the same type of sex hormones, which allows investigators to distinguish disease mechanisms influenced by the sex chromosomes. Supported by ORIP (R01OD030496, R21OD026560), NICHD, NIDDK, and NHLBI.
Metabolic Transitions Define Spermatogonial Stem Cell Maturation
Voigt et al., Human Reproduction. 2022.
https://www.doi.org/10.1093/humrep/deac157
The spermatogonial stem cell (SSC) is the basis of male fertility. One potential option to preserve fertility in patients treated with anti-cancer therapy is isolation and laboratory culture of the juvenile SSC pool with subsequent transplantation to restore spermatogenesis. However, efficient culture of undifferentiated spermatogonia, including SSCs, in mammals other than rodents remains challenging. Investigators reported that the metabolic phenotype of prepubertal human spermatogonia is distinct from that of adult spermatogonia and that SSC development is characterized by specific metabolic transitions from oxidative phosphorylation to anaerobic metabolism. Supported by ORIP (R01OD016575) and NICHD.
Early Treatment Regimens Achieve Sustained Virologic Remission in Infant Macaques Infected with SIV at Birth
Wang et al., Nature Communications. 2022.
https://www.doi.org/10.1038/s41467-022-32554-z
About 150,000 children are infected postnatally with HIV each year. Early antiretroviral therapy (ART) in infants with HIV can reduce viral reservoir size, but ART-free virologic remission has not been achieved. The researchers hypothesized that proviral reservoir seeding in infants exposed to HIV might differ from that in adults. They characterized viral reservoirs in neonatal rhesus macaques of both sexes inoculated with simian immunodeficiency virus (SIV) at birth and given combination ART. The researchers reported that 9 months of treatment initiated at day 3 resulted in a sustained virologic remission, suggesting that early intervention with proper treatment regimens could be an effective strategy. Supported by ORIP (P51OD011104), NIAID, NICHD, and NIDCR.
Parallel Processing, Hierarchical Transformations, and Sensorimotor Associations along the “Where” Pathway
Doudlah et al., eLife. 2022.
https://www.doi.org/10.7554/eLife.78712
Visually guided behaviors require the brain to transform ambiguous retinal images into object-level spatial representations and map those representations to motor responses. These capabilities are supported by the dorsal “where” pathway in the brain, but the specific contributions of areas along this pathway have remained elusive. Using a rhesus macaque model, researchers compared neuronal activity in two areas along the “where” pathway that bridge the parieto-occipital junction: intermediate visual area V3A and the caudal intraparietal (CIP) area. Neuronal activity was recorded while the animals made perceptual decisions based on judging the tilt of 3D visual patterns. The investigators found that CIP shows higher-order spatial representations and more choice-correlated responses, which support a V3A-to-CIP hierarchy. The researchers also discovered modulation of V3A activity by extraretinal factors, suggesting that V3A might be better characterized as contributing to higher-order behavioral functions rather than low-level visual feature processing. Supported by ORIP (P51OD011106), NEI, NICHD, and NINDS.
Effects of Ex Vivo Blood Anticoagulation and Preanalytical Processing Time on the Proteome Content of Platelets
Yunga et al., Journal of Thrombosis and Haemostasis. 2022.
https://www.doi.org/10.1111/jth.15694
The investigators studied how various blood anticoagulation options and processing times affect platelet function and protein content ex vivo. Using platelet proteome quantification and triple quadrupole mass spectrometry, they found that anticoagulant-specific effects on platelet proteomes included increased complement system and decreased α-granule proteins in platelets from EDTA-anticoagulated blood. Heparinized blood had higher levels of histone and neutrophil-associated proteins, as well as formation of platelet–neutrophil extracellular trap interactions in whole blood ex vivo. The study indicates that different anticoagulants and preanalytical processing times affect platelet function and platelet protein content ex vivo, suggesting more rigorous phenotyping strategies for platelet omics studies. Supported by ORIP (S10OD012246), NHLBI, NCI and NEI.