Selected Grantee Publications
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- 14 results found
- Microscopy
- Preservation
- 2021
Selective G Protein Signaling Driven by Substance P–Neurokinin Receptor Dynamics
Harris et al., Nature Chemical Biology. 2021.
https://www.nature.com/articles/s41589-021-00890-8
Investigators determined the cryogenic-electron microscopy structures of active neurokinin-1 receptor (NK1R) bound to neuropeptide substance P (SP) or the G protein q (Gq)-biased peptide SP6–11. Peptide interactions deep within NK1R are critical for receptor activation. Conversely, interactions between SP and NK1R extracellular loops are required for potent Gs-signaling but not Gq-signaling. Molecular dynamics simulations showed that these superficial contacts restrict SP flexibility. SP6–11, which lacks these interactions, is dynamic while bound to NK1R. Structural dynamics of NK1R agonists therefore depend on interactions with the receptor extracellular loops and regulate G protein signaling selectivity. This data unveils the molecular mechanism of how two stimuli (SP and Neurokinin A) yield distinct G protein signaling at the same G protein-coupled receptor. Supported by ORIP (S10OD021741, S10OD020054) and others.
Whole-Organism 3D Quantitative Characterization of Zebrafish Melanin by Silver Deposition Micro-CT
Katz et al., eLife. 2021.
https://www.biorxiv.org/content/10.1101/2021.03.11.434673v1
This research team combined micro-computed tomography (CT) with a novel application of ionic silver staining to characterize melanin distribution in whole zebrafish larvae. The resulting images enabled whole-body, computational analyses of regional melanin content and morphology. Normalized micro-CT reconstructions of silver-stained fish consistently reproduced pigment patterns seen by light microscopy and allowed direct quantitative comparisons of melanin content. Silver staining of melanin for micro-CT provides proof-of-principle for whole-body, 3D computational phenomic analysis of a specific cell type at cellular resolution. Advances such as this in whole-organism, high-resolution phenotyping provide superior context for studying the phenotypic effects of genetic, disease, and environmental variables. Supported by ORIP (R24OD018559).
Effects of Early Daily Alcohol Exposure on Placental Function and Fetal Growth in a Rhesus Macaque Model
Lo et al., American Journal of Obstetrics and Gynecology. 2021.
https://www.sciencedirect.com/science/article/pii/S0002937821008309?via%3Dihub=
In a rhesus macaque model for chronic prenatal alcohol exposure, daily consumption during early pregnancy significantly diminished placental perfusion at mid to late gestation and significantly decreased the oxygen supply to the fetal vasculature throughout pregnancy. These findings were associated with the presence of microscopic placental infarctions. Although placental adaptations may compensate for early environmental perturbations to fetal growth, placental blood flow and oxygenation were reduced, consistent with the evidence of placental ischemic injury that persisted throughout pregnancy. Supported by ORIP (P51OD011092), NICHD, and NIAAA.
Deep Learning-Based Framework for Cardiac Function Assessment in Embryonic Zebrafish from Heart Beating Videos
Naderi et al., Computers in Biology and Medicine. 2021.
https://www.sciencedirect.com/science/article/pii/S0010482521003590
Zebrafish is a powerful model system for a host of biological investigations, cardiovascular studies, and genetic screening. However, the current methods for quantifying and monitoring zebrafish cardiac functions involve tedious manual work and inconsistent estimations. Naderi et al. developed a Zebrafish Automatic Cardiovascular Assessment Framework (ZACAF) based on a U-net deep learning model for automated assessment of cardiovascular indices, such as ejection fraction (EF) and fractional shortening (FS) from microscopic videos of wildtype and cardiomyopathy mutant zebrafish embryos. The framework could be widely applicable with any laboratory resources, and the automatic feature holds promise to enable efficient, consistent, and reliable processing and analysis capacity. Supported by ORIP (R44OD024874)
Gut Germinal Center Regeneration and Enhanced Antiviral Immunity by Mesenchymal Stem/Stromal Cells
Weber et al., JCI Insight. 2021.
https://doi.org/10.1172/jci.insight.149033
Researchers investigated the effects of mesenchymal stem/stromal cell (MSC) infusions on gut mucosal recovery, antiviral immunity, and viral suppression in SIV-infected rhesus macaques. MSC treatment heightened virus-specific responses and reduced viral load. Clearance of SIV-positive cells from gut mucosal effector sites was correlated with regeneration of germinal centers, restoration of follicular B cells and T follicular helper cells, and enhanced antigen presentation by viral trapping within the follicular dendritic cell network. These changes were associated with enhanced gene expression for type I/II interferon signaling, B cell proliferation, and interleukin 7. MSC treatment also activated metabolic pathways associated with enhanced immunity and viral reduction. Supported by ORIP (P51OD011107) and NIAID.
In Vitro and In Vivo Functions of SARS-CoV-2 Infection-Enhancing and Neutralizing Antibodies
Li et al., Cell. 2021.
https://doi.org/10.1016/j.cell.2021.06.021
Antibody-dependent enhancement of infection is a concern for clinical use of antibodies. Researchers isolated neutralizing antibodies against the receptor-binding domain (RBD) or N-terminal domain (NTD) of SARS-CoV-2 spike from COVID-19 patients. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific binding modes. RBD and NTD antibodies mediated both neutralization and infection enhancement in vitro. However, infusion of these antibodies into mice or macaques resulted in suppression of virus replication, demonstrating that antibody-enhanced infection in vitro does not necessarily predict enhanced infection in vivo. RBD-neutralizing antibodies having cross-reactivity against coronaviruses were protective against SARS-CoV-2, the most potent of which was DH1047. Supported by ORIP (P40OD012217, U42OD021458, S10OD018164), NIAID, NCI, NIGMS, and NIH Common Fund.
Thioesterase Superfamily Member 1 Undergoes Stimulus-Coupled Conformational Reorganization to Regulate Metabolism in Mice
Li et al., Nature Communications. 2021.
https://doi.org/10.1038/s41467-021-23595-x
Thermogenesis is suppressed in brown adipose tissue by thioesterase superfamily member 1 (Them1), a long chain fatty acyl-CoA thioesterase. Them1 is highly upregulated by cold ambient temperature, where it reduces fatty acid availability and limits thermogenesis. Investigators show that Them1 regulates metabolism by undergoing conformational changes in response to β-adrenergic stimulation that alter Them1 intracellular distribution. Them1 forms metabolically active puncta near lipid droplets and mitochondria. Upon stimulation, Them1 is phosphorylated at the N-terminus, inhibiting puncta formation and activity, and resulting in a diffuse intracellular localization. Investigators show that Them1 puncta are biomolecular condensates that are inhibited by phosphorylation. Them1 forms intracellular biomolecular condensates that limit fatty acid oxidation and suppress thermogenesis. When energy is demanded, the condensates are disrupted by phosphorylation to allow for maximal thermogenesis. The stimulus-coupled reorganization of Them1 provides fine-tuning of thermogenesis and energy expenditure. Supported by ORIP (S10OD019988) and others.
Neutralizing Antibody Vaccine for Pandemic and Pre-Emergent Coronaviruses
Saunders et al., Nature. 2021.
https://doi.org/10.1038/s41586-021-03594-0
SARS-CoV-2 is a new member of the betacoronavirus (beta-CoV) genus, which also includes two common mild beta-CoVs and the life-threatening SARS-CoV-1 and MERS-CoV. Vaccines that elicit protective immunity against SARS-CoV-2 and beta-CoVs that circulate in animals could prevent future pandemics. Researchers designed a novel 24-mer SARS-CoV-2 receptor binding domain-sortase A conjugated nanoparticle vaccine (RBD-scNP). Investigators demonstrated that the immunization of macaques with RBD-scNP, and adjuvanted with 3M-052 and alum, elicits cross-neutralizing antibody responses against bat coronaviruses, SARS-CoV, and multiple SARS-CoV-2 variants of concern. This pioneering approach serves as a multimeric protein platform for the further development of generalized anti-beta-CoV vaccines. Supported by ORIP (U42OD021458), NIAID, and NCI.
Nonhuman Primate Models for SARS-CoV-2 Research: Cryopreservation as a Means to Maintain Critical Models and Enhance the Genetic Diversity of Colonies
Arnegard and Hild et al., Lab Animal. 2021.
https://doi.org/10.1038/s41684-021-00792-1
This commentary, written by ORIP staff, addresses the need for improved cryopreservation methods and resources for nonhuman primate (NHP) gametes and embryos to safeguard newly developed NHP models and enhance the genetic diversity of NHP colonies without reliance on animal importations. Cryopreservation also plays critical roles in medical approaches to preserve the fertility of patients who must undergo potentially gonadotoxic treatments, as well as nascent genome editing efforts to develop new NHP models for human diseases. Given these diverse benefits to research progress, ORIP continues to fund the development of cryopreservation tools and approaches for NHPs and other animal models.
Cryopreservation and Preparation of Thawed Spermatozoa from Rhesus Macaques (Macaca mulatta) for In Vitro Fertilization
De Carvalho et al., Journal of the American Association for Laboratory Animal Science. 2021.
https://www.ingentaconnect.com/content/aalas/jaalas/pre-prints/content-jaalas-20-000028
Optimizing procedures for cryopreservation and subsequent thawing for rhesus macaques is required to prevent cryodamage that negatively impacts artificial insemination and in vitro fertilization rates. Investigators systematically assessed two cryopreservation methods and four recovery methods in three interdependent experiments. Results demonstrated that slow-freezing, coupled with density gradient centrifugation provided the highest efficacy in functional sperm for in vitro use. Additional studies are required to further optimize sperm cryopreservation in rhesus macaques. Supported by ORIP (P51OD011092).