Selected Grantee Publications
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- 55 results found
- Microbiome
- Stem Cells/Regenerative Medicine
A Germ-Free Humanized Mouse Model Shows the Contribution of Resident Microbiota to Human-Specific Pathogen Infection
Wahl et al., Nature Biotechnology. 2023.
https://www.nature.com/articles/s41587-023-01906-5
Germ-free (GF) mice are of limited value in the study of human-specific pathogens because they do not support their replication. In this report, investigators developed a GF humanized mouse model using the bone marrow–liver–thymus platform to provide a robust and flexible in vivo model that can be used to study the role of resident microbiota in human health and disease. They demonstrated that resident microbiota promote viral acquisition and pathogenesis by using two human-specific pathogens, Epstein–Barr virus and HIV. Supported by ORIP (P40OD010995), FIC, NIAID, NCI, and NIDDK.
Allogeneic Immunity Clears Latent Virus Following Allogeneic Stem Cell Transplantation in SIV-Infected ART-Suppressed Macaques
Wu et al., Immunity. 2023.
https://doi.org/10.1016/j.immuni.2023.04.019
Allogeneic hematopoietic stem cell transplantation (alloHSCT) has been documented as curative for HIV, but the mechanisms are not yet known. Using Mauritian cynomolgus macaques of both sexes, researchers performed reduced-intensity alloHSCT experiments to define the individual contributions of allogeneic immunity and CCR5 deficiency to an alloHSCT-mediated HIV cure. They reported that allogeneic immunity was the major driver of reservoir clearance, mediating graft-versus-reservoir effects in HIV infection. Their results also point to a protective mechanism for CCR5 deficiency early during engraftment. Future efforts could focus on harnessing the beneficial effects of allogeneic immunity while avoiding graft-versus-host disease. Supported by ORIP (P51OD011092) and NIAID.
Ion Channel Function in Translational Bovine Gallbladder Cholangiocyte Organoids: Establishment and Characterization of a Novel Model System
Nagao and Ambrosini et al., Frontiers in Veterinary Science. 2023.
https://pubmed.ncbi.nlm.nih.gov/37303723/
The study of biliary physiology and pathophysiology has long been hindered by the lack of in vitro models that accurately reflect the complex functions of the biliary system. Recent advancements in 3D organoid technology may offer a promising solution to this issue. Bovine gallbladder models have recently gained attention in the investigation of human diseases due to their remarkable similarities in physiology and pathophysiology to the human gallbladder. In this study, the investigators successfully established and characterized bovine gallbladder cholangiocyte organoids (GCOs) that retain key characteristics of the gallbladder in vivo, including stem cell properties and proliferative capacity. Notably, their findings demonstrate that these organoids exhibit specific and functional cystic fibrosis transmembrane conductance regulator activity. These bovine GCOs represent a valuable tool for studying the physiology and pathophysiology of the gallbladder with human significance. Supported by ORIP (K01OD030515, R21OD031903).
Hematopoietic Stem Cells Preferentially Traffic Misfolded Proteins to Aggresomes and Depend on Aggrephagy to Maintain Protein Homeostasis
Chua et al., Cell Stem Cell. 2023.
https://pubmed.ncbi.nlm.nih.gov/36948186/
Investigators studied the mechanism of hematopoietic stem cells (HSCs) being dependent on managing proteostasis. Their findings demonstrated that HSCs preferentially depend on aggrephagy, a form of autophagy, to maintain proteostasis. When aggrephagy is disabled, HSCs compensate by increasing proteasome activity, but proteostasis is ultimately disrupted as protein aggregates accumulate and HSC function is impaired. The investigators also showed that Bag3 deficiency blunts aggresome formation in HSCs, resulting in protein aggregate accumulation, myeloid-biased differentiation, and diminished self-renewal activity, thus demonstrating Bag3 as a regulator of HSC proteostasis. HSC aging is associated with loss of aggresomes and reduced autophagic flux. Protein degradation pathways are thus configured in young-adult HSCs to preserve proteostasis and fitness but become dysregulated during aging. Supported by ORIP (S10OD032316, S10OD021831), NCI, and NIDDK.
In-Depth Virological and Immunological Characterization of HIV-1 Cure after CCR5A32/A32 Allogeneic Hematopoietic Stem Cell Transplantation
Jensen et al., Nature Medicine. 2023.
https://pubmed.ncbi.nlm.nih.gov/36807684/
Evidence suggests that CCR5Δ32/Δ32 hematopoietic stem cell transplantation (HSCT) can cure HIV-1, but the immunological and virological correlates are unknown. Investigators performed a longitudinal virological and immunological analysis of the peripheral blood and tissue compartments of a 53-year-old male patient more than 9 years after CCR5Δ32/Δ32 allogeneic HSCT and 48 months after analytical treatment interruption. Sporadic traces of HIV-1 DNA were detected in peripheral T cell subsets and tissue-derived samples, but repeated ex vivo quantitative and in vivo outgrowth assays in humanized mice of both sexes did not reveal replication-competent virus. This case provides new insights that could guide future cure strategies. Supported by ORIP (P51OD011092) and NIAID.
A Deep Learning Platform to Assess Drug Proarrhythmia Risk
Serrano et al., Cell Stem Cell. 2023.
https://www.sciencedirect.com/science/article/pii/S1934590922004866?via%3Dihub=
Investigators trained a convolutional neural network (CNN) classifier to learn and ultimately identify features of in vitro action potential recordings of human induced pluripotent stem cell (iPSC)–derived cardiomyocytes (hiPSC-CMs) that are associated with lethal Torsade de Pointes arrhythmia. The CNN classifier accurately predicted the risk of drug-induced arrhythmia. The risk profiles of the test drugs were similar across hiPSC-CMs derived from different healthy donors. In addition, pathogenic mutations that cause arrhythmogenic cardiomyopathies in patients significantly increased the proarrhythmic propensity to certain intermediate and high‑risk drugs in the hiPSC-CMs. These data indicate that deep learning can identify in vitro arrhythmic features that correlate with clinical arrhythmia and discern the influence of patient genetics on the risk of drug-induced arrhythmia. Supported by ORIP (S10OD030264) and NHLBI.
Human Hematopoietic Stem Cell Engrafted IL-15 Transgenic NSG Mice Support Robust NK Cell Responses and Sustained HIV-1 Infection
Abeynaike et al., Viruses. 2023.
https://www.mdpi.com/1999-4915/15/2/365
A major obstacle to human natural killer (NK) cell reconstitution is the lack of human interleukin‑15 (IL-15) signaling, as murine IL-15 is a poor stimulator of the human IL-15 receptor. Researchers show that immunodeficient NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice expressing a transgene encoding human IL-15 (NSG-Tg(IL-15)) have physiological levels of human IL-15 and support long-term engraftment of human NK cells when transplanted with human umbilical cord blood–derived hematopoietic stem cells (HSCs). These mice demonstrate robust and long-term reconstitution with human immune cells but do not develop graft-versus-host disease, allowing long-term studies of human NK cells. The HSC-engrafted mice can sustain HIV-1 infection, resulting in human NK cell responses. This work provides a robust novel model to study NK cell responses to HIV-1. Supported by ORIP (R24OD026440), NIAID, NCI, and NIDDK.
Gut Microbiome Dysbiosis in Antibiotic-Treated COVID-19 Patients Is Associated with Microbial Translocation and Bacteremia
Bernard-Raichon et al., Nature Communications. 2022.
https://www.doi.org/10.1038/s41467-022-33395-6
The investigators demonstrated that SARS-CoV-2 infection induced gut microbiome dysbiosis in male mice. Samples collected from human COVID-19 patients of both sexes also revealed substantial gut microbiome dysbiosis. Analysis of blood culture results testing for secondary microbial bloodstream infections with paired microbiome data indicated that bacteria might translocate from the gut into the systemic circulation of COVID-19 patients. These results were consistent with a direct role for gut microbiome dysbiosis in enabling dangerous secondary infections during COVID-19. Supported by ORIP (S10OD021747), NCI, NHLBI, NIAID, and NIDDK.
Sociability in a Non-Captive Macaque Population Is Associated with Beneficial Gut Bacteria
Johnson et al., Frontiers in Microbiology. 2022.
https://www.doi.org/10.3389/fmicb.2022.1032495
Social connections are essential for good health and well-being in social animals, such as humans and other primates. Increasingly, evidence suggests that the gut microbiome—through the so-called “gut–brain axis”—plays a key role in physical and mental health and that bacteria can be transmitted socially (e.g., through touch). Here, the authors explore behavioral variation in non‑captive rhesus macaques of both sexes with respect to the abundance of specific bacterial genera. Their results indicate that microorganisms whose abundance varies with individual social behavior also have functional links to host immune status. Overall, these findings highlight the connections between social behavior, microbiome composition, and health in an animal population. Supported by ORIP (P40OD012217) and NIMH.
Reduced Alcohol Preference and Intake after Fecal Transplant in Patients with Alcohol Use Disorder Is Transmissible to Germ-Free Mice
Wolstenholme et al., Nature Communications. 2022.
https://www.doi.org/10.1038/s41467-022-34054-6
Alcohol use disorder is a major cause of reduced life expectancy worldwide, and this misuse has increased exponentially during the COVID-19 pandemic. Fecal microbiota transplant has been shown previously to reduce alcohol craving in humans with cirrhosis. Here, the investigators report that the reduction in craving and alcohol preference is transmissible to male germ-free mice only when live bacteria—and not germ-free supernatants—are used for colonization. This differential colonization was associated with alterations in the gut immune–inflammatory response through short-chain fatty acids. Supported by ORIP (P40OD010995), NIAAA, NIDDK, and NIMH.