Selected Grantee Publications
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- 16 results found
- Microscopy
- 2022
- 2021
Gigapixel Imaging With a Novel Multi-Camera Array Microscope
Thomson et al., eLife. 2022.
https://www.doi.org/10.7554/eLife.74988
The dynamics of living organisms are organized across many spatial scales. The investigators created assembled a scalable multi-camera array microscope (MCAM) that enables comprehensive high-resolution, large field-of-view recording from multiple spatial scales simultaneously, ranging from structures that approach the cellular scale to large-group behavioral dynamics. By collecting data from up to 96 cameras, they computationally generated gigapixel-scale images and movies with a field of view over hundreds of square centimeters at an optical resolution of 18 µm. This system allows the team to observe the behavior and fine anatomical features of numerous freely moving model organisms on multiple spatial scales (e.g., larval zebrafish, fruit flies, slime mold). Overall, by removing the bottlenecks imposed by single-camera image acquisition systems, the MCAM provides a powerful platform for investigating detailed biological features and behavioral processes of small model organisms. Supported by ORIP (R44OD024879), NIEHS, NCI, and NIBIB.
SARS-CoV-2 Infects Neurons and Induces Neuroinflammation in a Non-Human Primate Model of COVID-19
Beckman et al., Cell Reports. 2022.
https://www.doi.org/10.1016/j.celrep.2022.111573
SARS-CoV-2 causes brain fog and other neurological complications in some patients. It has been unclear whether SARS-CoV-2 infects the brain directly or whether central nervous system sequelae result from systemic inflammatory responses triggered in the periphery. Using a rhesus macaque model, researchers detected SARS-CoV-2 in the olfactory cortex and interconnected regions 7 days after infection, demonstrating that the virus enters the brain through the olfactory nerve. Neuroinflammation and neuronal damage were more severe in elderly monkeys with type 2 diabetes. The researchers found that in aged monkeys, SARS-CoV-2 traveled farther along nerve pathways to regions associated with Alzheimer's disease. Supported by ORIP (P51OD011107) and NIA.
Molecular Insights Into Antibody-Mediated Protection Against the Prototypic Simian Immunodeficiency Virus
Zhao et al., Nature Communications. 2022.
https://www.doi.org/10.1038/s41467-022-32783-2
Most simian immunodeficiency virus (SIV) vaccines have focused on inducing T cell responses alone or in combination with non-neutralizing antibody responses. To date, studies investigating neutralizing antibody (nAb) responses to protect against SIV have been limited. In this study, researchers isolated 12 potent monoclonal nAbs from chronically infected rhesus macaques of both sexes and mapped their binding specificities on the envelope trimer structure. They further characterized the structures using cryogenic electron microscopy, mass spectrometry, and computational modeling. Their findings indicate that, in the case of humoral immunity, nAb activity is necessary and sufficient for protection against SIV challenge. This work provides structural insights for future vaccine design. Supported by ORIP (P51OD011106), NIAID, and NCI.
Functional and Ultrastructural Analysis of Reafferent Mechanosensation in Larval Zebrafish
Odstrcil et al., Current Biology. 2022.
https://www.sciencedirect.com/science/article/pii/S096098222101530X
All animals need to differentiate between exafferent stimuli (caused by the environment) and reafferent stimuli (caused by their own movement). Researchers characterized how hair cells in zebrafish larvae discriminate between reafferent and exafferent signals. Dye labeling of the lateral line nerve and functional imaging was combined with ultra-structural electron microscopy circuit reconstruction to show that cholinergic signals originating from the hindbrain transmit efference copies, and dopaminergic signals from the hypothalamus may affect threshold modulation. Findings suggest that this circuit is the core implementation of mechanosensory reafferent suppression in these young animals. Supported by ORIP (R43OD024879, R44OD024879) and NINDS.
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.