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.
A Multidimensional Metabolomics Workflow to Image Biodistribution and Evaluate Pharmacodynamics in Adult Zebrafish
Jackstadt et al., Disease Models & Mechanisms. 2022.
https://www.doi.org/10.1242/dmm.049550
The evaluation of tissue distribution and pharmacodynamic properties of a drug is essential but often expensive in clinical research. The investigators developed a multidimensional metabolomics platform to evaluate drug activity that integrates mass spectrometry–based imaging, absolute drug quantitation, in vivo isotope tracing, and global metabolome analysis in zebrafish. They validated this platform by evaluating whole-body distribution of the anti-rheumatic agent hydroxychloroquine sulfate and its impact on the systemic metabolism of adult zebrafish. This work suggests that the multidimensional metabolomics platform is a cost-effective method for evaluating on- and off-target effects of drugs. Supported by ORIP (R24OD024624) and NIEHS.
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.
Adverse Biobehavioral Effects in Infants Resulting from Pregnant Rhesus Macaques’ Exposure to Wildfire Smoke
Capitanio et al., Nature Communications. 2022.
https://www.doi.org/10.1038/s41467-022-29436-9
Exposure to wildfire smoke (WFS) is a growing health concern as wildfires increase in number and size due to climate change. Researchers found that developing rhesus monkeys exposed to WFS from the Camp Fire in California (November 2018) during the first third of gestation exhibited greater inflammation, blunted cortisol, more passive behavior, and memory impairment compared to animals conceived after smoke had dissipated. Analysis of a historical control cohort did not support the alternative hypothesis that conception timing alone explained the results. These findings suggest that WFS may have a teratogenic effect on neural development in the primate fetus. Supported by ORIP (P51OD011107, R24OD010962) and NIEHS.
A Potent Myeloid Response Is Rapidly Activated in the Lungs of Premature Rhesus Macaques Exposed to Intra-Uterine Inflammation
Jackson et al., Mucosal Immunology. 2022.
https://www.doi.org/10.1038/s41385-022-00495-x
Up to 40% of preterm births are associated with histological chorioamnionitis (HCA), which can lead to neonatal mortality, sepsis, respiratory disease, and neurodevelopmental problem. Researchers used rhesus macaques to comprehensively describe HCA-induced fetal mucosal immune responses and delineate the individual roles of IL-1β and TNFα in HCA-induced fetal pathology. Their data indicate that the fetal innate immune system can mount a rapid, multifaceted pulmonary immune response to in utero exposure to inflammation. Taken together, this work provides mechanistic insights into the association between HCA and the postnatal lung morbidities of the premature infant and highlights the therapeutic potential of inflammatory blockade in the fetus. Supported by ORIP (P51OD011107), NIEHS, NIDDK, NHLBI, and NICHD.
Inflammatory Blockade Prevents Injury to the Developing Pulmonary Gas Exchange Surface in Preterm Primates
Toth et al., Science Translational Medicine. 2022.
https://www.doi.org/10.1126/scitranslmed.abl8574
Chorioamnionitis, an inflammatory condition affecting the placenta and fluid surrounding the developing fetus, affects 25% to 40% of preterm births. Investigators used a prenatal rhesus macaque model to assess how fetal inflammation could affect lung development. They found that inflammatory injury directly disrupted the developing gas exchange surface of the primate lung, with extensive damage to alveolar structure. Blockade of the inflammatory cytokines IL-1β and TNFα ameliorated LPS-induced inflammatory lung injury by blunting stromal responses to inflammation and modulating innate immune activation in myeloid cells. These data provide new insight into key mechanisms of developmental lung injury and highlight targeted inflammatory blockade as a potential therapeutic approach to ameliorate lung injury in the neonatal population. Supported by ORIP (P51OD011107), NIAID, NHLBI, NICHD, and NIEHS.
Identification of Basp1 as a Novel Angiogenesis-regulating Gene by Multi-Model System Studies
Khajavi et al., FASEB Journal. 2021.
https://pubmed.ncbi.nlm.nih.gov/33899275/
The authors previously used genetic diversity in inbred mouse strains to identify quantitative trait loci (QTLs) responsible for differences in angiogenic response. Employing a mouse genome-wide association study (GWAS) approach, the region on chromosome 15 containing Basp1 was identified as being significantly associated with angiogenesis in inbred strains. To investigate its role in vivo, they knocked out basp1 in transgenic kdrl:zsGreen zebrafish embryos using a widely adopted CRISPR-Cas9 system. They further showed that basp1 promotes angiogenesis by upregulating β-catenin gene and the Dll4/Notch1 signaling pathway. These results provide the first in vivo evidence to indicate the role of basp1 as an angiogenesis-regulating gene. Supported by ORIP (R24OD017870) and NEI.
Fructose Stimulated De Novo Lipogenesis Is Promoted by Inflammation
Jelena et al., Nature Metabolism. 2020.
https://pubmed.ncbi.nlm.nih.gov/32839596
Non-alcoholic fatty liver disease (NAFD) affects 30% of adult Americans. While NAFD starts as simple steatosis with little liver damage, its severe manifestation as non-alcoholic steatohepatitis (NASH) is a leading cause of liver failure, cirrhosis, and cancer. Fructose consumption is proposed to increase the risk of hepatosteatosis and NASH. Excessive intake of fructose causes barrier deterioration and low-grade endotoxemia. Using a mouse model, the study examined the mechanism of how fructose triggers these alterations and their roles in hepatosteatosis and NASH pathogenesis. The results demonstrated that microbiota-derived Toll-like receptor (TLR) agonists promote hepatosteatosis without affecting fructose-1-phosphate (F1P) and cytosolic acetyl-CoA. Activation of mucosal-regenerative gp130 signaling, administration of the YAP-induced matricellular protein CCN1 or expression of the antimicrobial peptide Reg3b (beta) counteract fructose-induced barrier deterioration, which depends on endoplasmic-reticulum stress and subsequent endotoxemia. Endotoxin engages TLR4 to trigger TNF production by liver macrophages, thereby inducing lipogenic enzymes that convert F1P and acetyl-CoA to fatty acid in both mouse and human hepatocytes. The finding may be of relevance to several common liver diseases and metabolic disorders. Supported by ORIP (S10OD020025), NCI, NIEHS, NIDDK, NIAID, and NIAAA.
Fluorescence-Based Sorting of Caenorhabditis elegans via Acoustofluidics
Zhang et al., Lab on a Chip. 2020.
The authors present an integrated acoustofluidic chip capable of identifying worms of interest based on expression of a fluorescent protein in a continuous flow and then separate them in a high-throughput manner. Utilizing planar fiber optics, their acoustofluidic device requires no temporary immobilization of worms for interrogation/detection, thereby improving the throughput. The device can sort worms of different developmental stages (L3 and L4 stage worms) at high throughput and accuracy. In their acoustofluidic chip, the time to complete the detection and sorting of one worm is only 50 ms, which outperforms nearly all existing microfluidics-based worm sorting devices. Supported by ORIP (R43OD024963), NIEHS, and NIDDK.