Selected Grantee Publications
The Landscape of Tolerated Genetic Variation in Humans and Primates
Gao et al., Science. 2023.
Investigators created a whole-genome sequence database from 809 nonhuman primates (NHPs) of 233 species to test the hypothesis that gene variants that do not cause disease in NHPs would likely be benign also in humans. They found that 99% of the genetic variants that were benign in NHPs also were classified as benign in the human ClinVar database. In contrast, only 71% to 87% of genomic variants classified as benign in non-primate animals were benign in humans. Building on this approach, the authors reclassified more than 4 million human genetic variants of unknown health impact as likely being benign based on effects in NHPs. This work illustrates the power of comparative medicine approaches between NHPs and humans. Supported by ORIP (P40OD024628, P51OD011106) and NIGMS.
The Drosophila Chemokine-Like Orion Bridges Phosphatidylserine and Draper in Phagocytosis of Neurons
Ji et al., PNAS. 2023.
https://pubmed.ncbi.nlm.nih.gov/37276397/
Degenerating neurons can be cleared by phagocytosis triggered by “eat-me” signal phosphatidylserine (PS) and mediated by the engulfment receptor Draper (Drpr), yet the process is poorly understood. Investigators used several Drosophila models to study dendrite degeneration and demonstrated that the fly chemokine-like protein Orion binds to PS and mediates interactions between PS and Drpr to enable phagocytosis. This study identifies a link between immunomodulatory proteins and phagocytosis of neurons and reveals conserved mechanisms of clearing degenerating neurons. Supported by ORIP (R24OD031953, R21OD023824, S10OD018516) and NINDS.
p38MAPKα Stromal Reprogramming Sensitizes Metastatic Breast Cancer to Immunotherapy
Faget et al., Cancer Discovery. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10238649/
This study emphasizes the importance of the metastatic tumor microenvironment in metastatic breast cancer growth and the identification of effective antimetastatic therapies. Using a stromal labeling approach and single-cell RNA sequencing, the authors showed that a combination of p38MAPK inhibition (p38i) and anti-OX40 synergistically reduced metastatic tumor growth and increased overall survival. Further engagement of cytotoxic T cells cured all metastatic disease in mice and produced durable immunologic memory. The Cancer Genome Atlas data analysis revealed that patients with p38i metastatic stromal signature and a high tumor mutational burden (TMB) had increased overall survival. These findings suggest that patients with high TMB would benefit the most from the p38i plus anti-OX40 approach. Supported by ORIP (S10OD028483), NIA, NCI, and NIGMS.
Lymph-Node-Based CD3+ CD20+ Cells Emerge From Membrane Exchange Between T Follicular Helper Cells and B Cells and Increase Their Frequency Following Simian Immunodeficiency Virus Infection
Samer et al., Journal of Virology. 2023.
https://www.doi.org/10.1128/jvi.01760-22
CD4+ T follicular helper cells are known to persist during antiretroviral therapy (ART) and have been identified as key targets for viral replication and persistence. Researchers identified a lymphocyte population that expresses CD3 (i.e., T cell lineage marker) and CD20 (i.e., B cell lineage marker) on the cellular surface in lymphoid tissues from rhesus macaques of both sexes and humans of male and female sexes. In macaques, the cells increased following simian immunodeficiency virus infection, were reduced with ART, and increased in frequency after ART interruption. These cells represent a potential area for future therapeutic strategies. Supported by ORIP (P51OD011132, U42OD011023), NIAID, NCI, NIDDK, NIDA, NHLBI, and NINDS.
Infection of the Maternal–Fetal Interface and Vertical Transmission Following Low-Dose Inoculation of Pregnant Rhesus Macaques (Macaca mulatta) with an African-Lineage Zika Virus
Koenig et al., PLOS ONE. 2023.
https://doi.org/10.1371/journal.pone.0284964
Researchers examined transmission of Zika virus to nonhuman primate fetuses during pregnancy. Even with a low dosage of inoculation of the dams, the investigators found that the Zika virus infected fetuses, despite the presence of a “placental fortress,” which normally protects fetuses during gestation. This transmission illustrates the high level of infectivity threat that Zika poses, which may increase if mosquitoes expand their global habitats. Understanding how Zika breaches the placental barrier will help researchers develop strategies to prevent fetal infection during pregnancy and thereby prevent adverse outcomes, such as brain malformation defects. Supported by ORIP (P51OD011106, S10OD023526), NIAID, NCI, and NIGMS.
Cell-Type Memory in a Single-Cell Eukaryote Requires the Continuous Presence of a Specific Transcription Regulator
Lee et al., PNAS. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10214202/
Investigators studied the fundamental question and underlying mechanism of how a eukaryotic cell type can be stably maintained through many rounds of DNA replication and cell division in a fungal species where two different cell types (i.e., white and opaque) arise from the same genome. Investigators found that destruction of Wor1, the primary transcription activator of the opaque state, led opaque cells to irreversibly lose their memory and switch to the white-cell state within about 1 hour. This study demonstrates that the continuous presence of Wor1 is needed to maintain the opaque cell state. Data also suggested that a threshold concentration of Wor1 is needed to maintain the opaque state, indicating the importance of the transcription factor in maintaining cell-type memory. Supported by ORIP (S10OD028511), NIAID, and NIGMS.
CD8+ T Cells Promote HIV Latency by Remodeling CD4+ T Cell Metabolism to Enhance Their Survival, Quiescence, and Stemness
Mutascio et al., Immunity. 2023.
https://www.doi.org/10.1016/j.immuni.2023.03.010
An HIV reservoir persists following antiretroviral therapy, representing the main barrier to an HIV cure. Using a validated in vitro model, investigators explored the mechanism by which CD8+ T cells promote HIV latency and inhibit latency reversal in HIV-infected CD4+ T cells. They reported that CD8+ T cells favor the establishment of HIV latency by modulating metabolic, stemness, and survival pathways that correlate with the downregulation of HIV expression and promote HIV latency. In future studies, comparative analyses may provide insight into common molecular mechanisms in the silencing of HIV expression by CD8+ T cells and macrophages, which can be applied to new intervention strategies that target the HIV reservoir. Supported by ORIP (P51OD011132, S10OD026799), NIAID, NIDDK, NIDA, NHLBI, and NINDS.
In Vivo MRI Is Sensitive to Remyelination in a Nonhuman Primate Model of Multiple Sclerosis
Donadieu et al., eLife. 2023.
https://pubmed.ncbi.nlm.nih.gov/37083540/
Experimental autoimmune encephalomyelitis (EAE) in the common marmoset is a model for studying inflammatory demyelination in multiple sclerosis (MS). Researchers investigated the feasibility and sensitivity of magnetic resonance imaging (MRI) in characterizing remyelination, a crucial step to recover from MS. Investigators demonstrated that multisequence 7T MRI could detect spontaneous remyelination in marmoset EAE at high statistical sensitivity and specificity in vivo. This study suggests that in vivo MRI can be used for preclinical testing of therapeutic remyelinating agents for MS. Supported by ORIP (R21OD030163) and NINDS.
An E1–E2 Fusion Protein Primes Antiviral Immune Signaling in Bacteria
Ledvina et al., Nature. 2023.
https://www.nature.com/articles/s41586-022-05647-4
Investigators show that the cGAS/DncV–like nucleotidyltransferase (CD‑NTase)–associated protein 2 (Cap2) primes bacterial CD-NTases for activation through a ubiquitin transferase–like mechanism. A cryo-electron microscopy structure of the Cap2-CD-NTase complex reveals Cap2 as an all-in-one ubiquitin transferase–like protein, with distinct domains resembling eukaryotic E1 and E2 proteins. The structure captures a reactive-intermediate state with the CD-NTase C terminus positioned in the Cap2 E1 active site and conjugated to AMP. Cap2 conjugates the CD-NTase C terminus to a target molecule that primes the CD-NTase for increased cGAMP production. The investigators further demonstrate bacteria control immune signaling using an ancient, minimized ubiquitin transferase–like system and provide insight into the evolution of the E1 and E2 machinery across domains of life. Supported by ORIP (S10OD023498, S10OD021527, S10OD025267) and NIGMS.
Resolution of Structural Variation in Diverse Mouse Genomes Reveals Chromatin Remodeling due to Transposable Elements
Ferraj et al., Cell Genomics. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10203049/
Diverse inbred mouse strains are important biomedical research models, yet genome characterization of many strains is fundamentally lacking in comparison with humans. Here, investigators used long-read whole genome sequencing to assemble the genomes of 20 diverse inbred laboratory strains of mice. From whole-genome comparisons, they generated a sequence-resolved callset of 413,758 structural variants. These data are presented as a comprehensive resource that can be used for future genomic studies, aid in modeling and studying the effects of genetic variation, and enhance genotype-to-phenotype research. Supported by ORIP (R24OD021325), NCI, NIGMS, and NHGRI.