Selected Grantee Publications
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- 35 results found
- S10 [SIG, BIG, HEI]
- Genetics
Natural Killer–Like B Cells Are a Distinct but Infrequent Innate Immune Cell Subset Modulated by SIV Infection of Rhesus Macaques
Manickam et al., PLOS Pathogens. 2024.
https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1012223
Natural killer–like B (NKB) cells express both natural killer (NK) and B cell receptors. Intracellular signaling proteins and trafficking markers were expressed differentially on naive NKB cells. CD20+ NKG2A/C+ NKB cells were identified in organs and lymph nodes of naive rhesus macaques (RMs). Single-cell RNA sequencing (scRNAseq) of sorted NKB cells confirmed that NKB cells are unique, and transcriptomic analysis of naive splenic NKB cells by scRNAseq showed that NKB cells undergo somatic hypermutation and express Ig receptors, similar to B cells. Expanded NKB frequencies were observed in RM gut and buccal mucosa after simian immunodeficiency virus (SIV) infection, and mucosal and peripheral NKB cells were associated with colorectal cytokine milieu and oral microbiome changes. NKB cells gated on CD3-CD14-CD20+NKG2A/C+ cells were inclusive of transcriptomically conventional B and NK cells in addition to true NKB cells, confounding accurate phenotyping and frequency recordings. Supported by ORIP (P51OD011132, S10OD026799) and NIAID.
Obesity Causes Mitochondrial Fragmentation and Dysfunction in White Adipocytes Due to RalA Activation
Xia et al., Nature Metabolism. 2024.
https://pubmed.ncbi.nlm.nih.gov/38286821/
This study presents a molecular mechanism for mitochondrial dysfunction as a characteristic trait of obesity. Chronic activation of the small GTPase RalA in inguinal white adipocytes (iWAT), in male mice fed a high-fat diet (HFD) represses energy expenditure by shifting mitochondrial dynamics toward excessive fission, contributing to weight gain and metabolic dysfunction. Targeted deletion of RalA in iWAT attenuated HFD-induced obesity due to increased energy expenditure and mitochondrial oxidative phosphorylation. Mechanistically, RalA dephosphorylates inhibitory Serine637 on fission protein Drp1, leading to excessive fission in adipocytes and mitochondrial fragmentation. Expression of a human homolog of Drp1—DNM1L—in adipose tissue is positively correlated with obesity and insulin resistance. These findings open avenues to investigate RalA-Drp1 axis in energy homeostasis. Supported by ORIP (S10OD023527), NCI, NHLBI, and NIDDK.
Macrophages Derived From Human Induced Pluripotent Stem Cells (iPSCs) Serve As a High-Fidelity Cellular Model for Investigating HIV-1, Dengue, and Influenza viruses
Yang et al., Journal of Virology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38323811/
Macrophages can be weaponized by viruses to host viral reproduction and support long-term persistence. The most common way of studying these cells is by isolating their precursors from donor blood and differentiating the isolated cells into macrophages. This method is costly and technically challenging, and it produces varying results. In this study, researchers confirmed that macrophages derived from iPSC cell lines—a model that is inexpensive, consistent, and modifiable by genome editing—are a suitable model for experiments involving HIV and other viruses. Macrophages derived from iPSCs are as susceptible to infection as macrophages derived from blood, with similar infection kinetics and phenotypes. This new model offers researchers an unlimited source of cells for studying viral biology. Supported by ORIP (R01OD034046, S10OD021601), NIAID, NIDA, NIGMS, and NHLBI.
Large-Scale Production of Human Blastoids Amenable to Modeling Blastocyst Development and Maternal-Fetal Crosstalk
Yu et al., Cell Stem Cell. 2023.
https://www.sciencedirect.com/science/article/abs/pii/S1934590923002850?via%3Dihub=
Human blastoids provide a valuable model to study early human development and implantation with reduced genetic heterogeneity between samples. Investigators reported a protocol for efficient generation of high-fidelity human blastoids from naïve pluripotent stem cells. The similarities between blastoids and blastocysts in signaling activities—demonstrated using single-cell RNA sequencing—support the use of blastoids to model lineage differentiation and cavity formation. Additionally, endometrial stromal effects in promoting trophoblast cell survival, proliferation, and syncytialization during co-culture with blastoids demonstrated the capability to model maternal–fetal crosstalk. The protocol will facilitate broader use of human blastoids as an ethical model for human blastocysts. Supported by ORIP (S10OD028630) and others.
SALL1 Enforces Microglia-Specific DNA Binding and Function of SMADs to Establish Microglia Identity
Fixsen et al., Nature Immunology. 2023.
https://doi.org/10.1038/s41590-023-01528-8
Microglia function is thought to play a role in neurodevelopmental, psychiatric, and neurodegenerative diseases. Using knockout mice, investigators explored functional interactions between spalt-like transcription factor 1 (SALL1) and SMAD4, which demonstrated that interactions are mediated by a conserved microglia-specific SALL1 super-enhancer and result in direct activation of regulatory elements. The concerted interactions induce a microglia lineage determining program of gene expression. These findings indicate that expression of SALL1 and associated genes could contribute to phenotypes of aging and neurodegenerative diseases. Supported by ORIP (S10OD026929), NIA, NIMH, and NINDS.
Epigenetic Dysregulation From Chromosomal Transit in Micronuclei
Agustinus et al., Nature . 2023.
https://www.nature.com/articles/s41586-023-06084-7
The authors reported a mechanistic link between epigenetic alterations and chromosomal instability induced during their transit in micronuclei, both being hallmarks of advanced and metastatic cancers. It was demonstrated that the landscape of histone post-translational modifications was profoundly changed due to missegregation of mitotic chromosomes, their sequestration in micronuclei and subsequent rupture of the micronuclear envelope. The transcriptional redistribution was attributed to micronuclei’s strong positional bias with increased promoter accessibility. The continuous formation and reincorporation of micronuclei promotes epigenetic reprogramming and heterogeneity in cancer. Supported by ORIP (S10OD030286) and others.
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.
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.
Spike and Nsp6 Are Key Determinants of SARS-CoV-2 Omicron BA.1 Attenuation
Chen et al., Nature. 2023.
https://pubmed.ncbi.nlm.nih.gov/36630998/
The ability of the SARS-CoV-2 virus to mutate and create variants of concern demands new vaccines to control the COVID-19 pandemic. The SARS-CoV-2 Omicron variant was shown to be more immune evasive and less virulent than current major variants. The spike (S) protein in this variant carries many mutations that drive these phenotypes. Researchers generated a chimeric recombinant SARS-CoV-2 virus encoding the S gene of Omicron (BA.1 lineage) in an ancestral SARS-CoV-2 isolate and compared it with the naturally circulating Omicron variant. The Omicron S-bearing virus escaped vaccine-induced humoral immunity, owing to mutations in the receptor-binding motif. The recombinant virus replicated efficiently in distal lung cell lines and in K18-hACE2 mice. Moreover, mutations induced in non-structural protein 6 (nsp6) in addition to the S protein were sufficient to restate the attenuated phenotype of Omicron. These findings indicate that the pathogenicity of Omicron is determined by mutations both inside and outside of the S gene. Supported by ORIP (S10OD026983, S10OD030269).
PIKFYVE Inhibition Mitigates Disease in Models of Diverse Forms of ALS
Hung et al., Cell . 2023.
https://doi.org/10.1016/j.cell.2023.01.005
Investigators showed that pharmacological suppression of PIKFYVE activity reduces pathology and extends survival of animal models and patient-derived motor neurons representing diverse forms of amyotrophic lateral sclerosis (ALS). Upon PIKFYVE inhibition, exocytosis is activated to transport aggregation-prone proteins out of the cells, a process that does not require stimulating macroautophagy or the ubiquitin-proteosome system. These findings suggest therapeutic potential to manage multiple forms of ALS. Supported by ORIP (S10OD021553) and NINDS.