Selected Grantee Publications
Vaccination Induces Broadly Neutralizing Antibody Precursors to HIV gp41
Schiffner et al., Nature Immunology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38816615
Primary immunogens that induce rare broadly neutralizing antibody (bnAb) precursor B cells are needed to develop vaccines against viruses of high antigenic diversity. 10E8-class bnAbs must possess a long, heavy chain complementarity determining region 3 (HCDR3) with a specific binding motif. Researchers developed germline-targeting epitope scaffolds with an affinity for 10E8-class precursors that exhibited epitope structural mimicry and bound bnAb-precursor human naive B cells in ex vivo screens. Protein nanoparticles induced bnAb-precursor responses in stringent mouse models and rhesus macaques, and mRNA-encoded nanoparticles triggered similar responses in mice. This study showed that germline-targeting epitope scaffold nanoparticles can elicit rare bnAb-precursor B cells with predefined binding specificities and HCDR3 features. Supported by ORIP (P51OD011132, U42OD011023), NIAID, and NIGMS.
Integrin αvβ3 Upregulation in Response to Nutrient Stress Promotes Lung Cancer Cell Metabolic Plasticity
Nam, Cancer Research. 2024.
https://pubmed.ncbi.nlm.nih.gov/38588407/
Tumor-initiating cells can survive in harsh environments via stress tolerance and metabolic flexibility; studies on this topic can yield new targets for cancer therapy. Using cultured cells and live human surgical biopsies of non-small cell lung cancer, researchers demonstrated that nutrient stress drives a metabolic reprogramming cascade that allows tumor cells to thrive despite a nutrient-limiting environment. This cascade results from upregulation of integrin αvβ3, a cancer stem cell marker. In mice, pharmacological or genetic targeting prevented lung cancer cells from evading the effects of nutrient stress, thus blocking tumor initiation. This work suggests that this molecular pathway leads to cancer stem cell reprogramming and could be linked to metabolic flexibility and tumor initiation. Supported by ORIP (K01OD030513), NCI, NIGMS, and NINDS.
Potent HPIV3-Neutralizing IGHV5-51 Antibodies Identified from Multiple Individuals Show L Chain and CDRH3 Promiscuity
Abu-Shmais et al., Journal of Immunology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38488511/
Human parainfluenza virus 3 fusion glycoprotein (HPIV3 F), responsible for facilitating viral entry into host cells, is a major target of neutralizing antibodies that inhibit infection. More work is needed to understand these dynamics. Researchers characterized the genetic signatures, epitope specificity, neutralization potential, and publicness of HPIV3-specific antibodies identified across multiple individuals. From this work, they identified 12 potently neutralizing antibodies targeting three nonoverlapping epitopes on HPIV3 F. Six of the antibodies used immunoglobulin heavy variable gene, IGHV 5-51. These antibodies used different L chain variable genes (VL) and diverse H chain CDR 3 (CDRH3) sequences. These findings help elucidate the genetic and functional characteristics of HPIV3-neutralizing antibodies and indicate the existence of a reproducible H chain variable–dependent antibody response associated with VL and CDRH3 promiscuity. Supported by ORIP (K01OD036063), NCATS, NCI, NEI, NIAID, and NIDDK.
Murine MHC-Deficient Nonobese Diabetic Mice Carrying Human HLA-DQ8 Develop Severe Myocarditis and Myositis in Response to Anti-PD-1 Immune Checkpoint Inhibitor Cancer Therapy
Racine et al., Journal of Immunology. 2024.
Myocarditis has emerged as a relatively rare but often lethal autoimmune complication of checkpoint inhibitor (ICI) cancer therapy, and significant mortality is associated with this phenomenon. Investigators developed a new mouse model system that spontaneously develops myocarditis. These mice are highly susceptible to myocarditis and acute heart failure following anti-PD-1 ICI-induced treatment. Additionally, the treatment accelerates skeletal muscle myositis. The team performed characterization of cardiac and skeletal muscle T cells using histology, flow cytometry, adoptive transfers, and RNA sequencing analyses. This study sheds light on underlying immunological mechanisms in ICI myocarditis and provides the basis for further detailed analyses of diagnostic and therapeutic strategies. Supported by ORIP (U54OD020351, U54OD030187), NCI, NIA, NIDDK, and NIGMS.
Proof-of-Concept Studies With a Computationally Designed Mpro Inhibitor as a Synergistic Combination Regimen Alternative to Paxlovid
Papini et al., PNAS. 2024.
As the spread and evolution of SARS-CoV-2 continues, it is important to continue to not only work to prevent transmission but to develop improved antiviral treatments as well. The SARS-CoV-2 main protease (Mpro) has been established as a prominent druggable target. In the current study, investigators evaluate Mpro61 as a lead compound, utilizing structural studies, in vitro pharmacological profiling to examine possible off-target effects and toxicity, cellular studies, and testing in a male and female mouse model for SARS-CoV-2 infection. Results indicate favorable pharmacological properties, efficacy, and drug synergy, as well as complete recovery from subsequent challenge by SARS-CoV-2, establishing Mpro61 as a promising potential preclinical candidate. Supported by ORIP (R24OD026440, S10OD021527), NIAID, and NIGMS.
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.
SHIV-C109p5 NHP Induces Rapid Disease Progression in Elderly Macaques with Extensive GI Viral Replication
Bose et al., Journal of Virology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38299866/
Researchers are interested in developing animal models infected with simian–human immunodeficiency virus (SHIV) to better understand prevention of HIV acquisition. Researchers generated pathogenic SHIV clade C transmitted/founder stock by in vivo passage using geriatric rhesus macaques of both sexes. They reported that the infection resulted in high sustained viral loads and induced rapid pathology and wasting, necessitating euthanasia between 3 and 12 weeks post-infection. The extensive viral replication in gut and lymphoid tissues indicated a fit viral stock. This work provides a new nonhuman primate model for HIV pathogenicity and cure studies. Supported by ORIP (R24OD010947) 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.
Tumor Explants Elucidate a Cascade of Paracrine SHH, WNT, and VEGF Signals Driving Pancreatic Cancer Angiosuppression
Hasselluhn et al., Cancer Discovery. 2024.
https://pubmed.ncbi.nlm.nih.gov/37966260/
This study presents a key mechanism that prevents pancreatic ductal adenocarcinoma (PDAC) from undergoing neoangiogenesis, which affects its development, pathophysiology, metabolism, and treatment response. Using human and murine PDAC explants, which effectively retain the complex cellular interactions of native tumor tissues, and single-cell regulatory network analysis, the study identified a cascade of three paracrine pathways bridging between multiple cell types and acting sequentially, Hedgehog to WNT to VEGF, as a key suppressor of angiogenesis in KRAS-mutant PDAC cells. This study provides an experimental paradigm for dissecting higher-order cellular interactions in tissues and has implications for PDAC treatment strategies. Supported by ORIP (S10OD012351, S10OD021764), NCI, and NIDDK.
Intestinal Epithelial Adaptations to Vertical Sleeve Gastrectomy Defined at Single-Cell Resolution
Koch-Laskowski et al., Genomics. 2024.
https://pubmed.ncbi.nlm.nih.gov/38309446/
Perturbations in the intestinal epithelium have been linked to the pathogenesis of metabolic disease. Bariatric procedures, such as vertical sleeve gastrectomy (VSG), cause gut adaptations that induce robust metabolic improvements. Using a male mouse model, the authors assessed the effects of VSG on different cell lineages of the small intestinal epithelium. They show that Paneth cells display increased expression of the gut peptide Reg3g after VSG. Additionally, VSG restores pathways pertaining to mitochondrial respiration and cellular metabolism, especially within crypt-based cells. Overall, this work demonstrates how adaptations among specific cell types can affect gut epithelial homeostasis; these findings can help researchers develop targeted, less invasive treatment strategies for metabolic disease. Supported by ORIP (F30OD031914), NCI, and NIDDK.