Selected Grantee Publications
A Comprehensive Atlas of AAV Tropism in the Mouse
Walkey et al., Molecular Therapy. 2025.
https://pubmed.ncbi.nlm.nih.gov/39863928
Over the past three decades, adeno-associated viruses (AAVs) have emerged as the leading viral vector for in vivo gene therapy. This study presents a comprehensive atlas of AAV tropism in male and female mice, evaluating 10 naturally occurring AAV serotypes across 22 tissues using systemic delivery. Researchers employed a fluorescent protein activation approach to visualize AAV transduction patterns and detected transduction of unexpected tissues, including in adrenal glands, testes, and ovaries. Biodistribution closely matched the fluorescent signal intensity. This publicly available data set provides valuable insights into AAV vector targeting and supports optimal serotype selection for basic research and preclinical gene therapy applications in murine models. Supported by ORIP (U42OD026645, U42OD035581, U42OD026635), NCI, NHLBI, NICHD, and NIDDK.
In Vivo Expansion of Gene-Targeted Hepatocytes Through Transient Inhibition of an Essential Gene
De Giorgi et al., Science Translational Medicine. 2025.
https://pubmed.ncbi.nlm.nih.gov/39937884
This study explores Repair Drive, a platform technology that selectively expands homology-directed repair for treating liver diseases in male and female mice. Through transient conditioning of the liver by knocking down an essential gene—fumarylacetoacetate hydrolase—and delivering an untraceable version of that essential gene with a therapeutic transgene, Repair Drive significantly increases the percentage of gene-targeted hepatocytes (liver cells) up to 25% without inducing toxicity or tumorigenesis after a 1-year follow-up. This also resulted in a fivefold increase in expression of human factor IX, a therapeutic transgene. Repair Drive offers a promising platform for precise, safe, and durable correction of liver-related genetic disorders and may expand the applicability of somatic cell genome editing in a broad range of liver diseases in humans. Supported by ORIP (U42OD035581, U42OD026645), NCI, NHLBI, and NIDDK.
Lipid Nanoparticle-Mediated mRNA Delivery to CD34+ Cells in Rhesus Monkeys
Kim et al., Nature Biotechnology. 2024.
https://pubmed.ncbi.nlm.nih.gov/39578569
Blood cells, which are derived from hematopoietic stem cells (HSCs), promote pathologies including anemia, sickle cell disease, immunodeficiency, and metabolic disorders when dysfunctional. Because of the morbidity that results from the bone marrow mobilization and chemotherapy patient conditioning of current HSC therapies, novel treatment strategies that deliver RNA to HSCs are needed. Researchers found a lipid nanoparticle (LNP), LNP67, that delivers messenger RNA (mRNA) to murine HSCs in vivo and human HSCs ex vivo without the use of a cKit-targeting ligand. When tested in 7- to 8-month-old male and female rhesus monkeys, LNP67 successfully delivered mRNA to CD34+ cells and liver cells without adverse effects. These results show the potential translational relevance of an in vivo LNP–mRNA drug. Supported by ORIP (U42OD027094, P51OD011107), NIDDK, and NCATS.
Amphiphilic Shuttle Peptide Delivers Base Editor Ribonucleoprotein to Correct the CFTR R553X Mutation in Well-Differentiated Airway Epithelial Cells
Kulhankova et al., Nucleic Acids Research. 2024.
https://academic.oup.com/nar/article/52/19/11911/7771564?login=true
Effective translational delivery strategies for base editing applications in pulmonary diseases remain a challenge because of epithelial cells lining the intrapulmonary airways. The researchers demonstrated that the endosomal leakage domain (ELD) plays a crucial role in gene editing ribonucleoprotein (RNP) delivery activity. A novel shuttle peptide, S237, was created by flanking the ELD with poly glycine-serine stretches. Primary airway epithelia with the cystic fibrosis transmembrane conductance regulator (CFTR) R533X mutation demonstrated restored CFTR function when treated with S237-dependent ABE8e-Cas9-NG RNP. S237 outperformed the S10 shuttle peptide at Cas9 RNP delivery in vitro and in vivo using primary human bronchial epithelial cells and transgenic green fluorescent protein neonatal pigs. This study highlights the efficacy of S237 peptide–mediated RNP delivery and its potential as a therapeutic tool for the treatment of cystic fibrosis. Supported by ORIP (U42OD027090, U42OD026635), NCATS, NHGRI, NHLBI, NIAID, NIDDK, and NIGMS.
Systematic Multi-trait AAV Capsid Engineering for Efficient Gene Delivery
Eid et al., Nature Communications. 2024.
https://doi.org/10.1038/s41467-024-50555-y
Engineering novel functions into proteins while retaining desired traits is a key challenge for developers of viral vectors, antibodies, and inhibitors of medical and industrial value. In this study, investigators developed Fit4Function, a generalizable machine learning (ML) approach for systematically engineering multi-trait adeno-associated virus (AAV) capsids. Fit4Function was used to generate reproducible screening data from a capsid library that samples the entire manufacturable sequence space. The Fit4Function data were used to train accurate sequence-to-function models, which were combined to develop a library of capsid candidates. Compared to AAV9, top candidates from the Fit4Function capsid library exhibited comparable production yields; more efficient murine liver transduction; up to 1,000-fold greater human hepatocyte transduction; and increased enrichment in a screen for liver transduction in macaques. The Fit4Function strategy enables prediction of peptide-modified AAV capsid traits across species and is a critical step toward assembling an ML atlas that predicts AAV capsid performance across dozens of traits. Supported by ORIP (P51OD011107, U42OD027094), NIDDK, NIMH, and NINDS.
Anti–PD-1 Chimeric Antigen Receptor T Cells Efficiently Target SIV-Infected CD4+ T Cells in Germinal Centers
Eichholtz et al., The Journal of Clinical Investigation. 2024.
https://pubmed.ncbi.nlm.nih.gov/38557496/
Researchers conducted adoptive transfer of anti–programmed cell death protein 1 (PD-1) chimeric antigen receptor (CAR) T cells in simian immunodeficiency virus (SIV)–infected rhesus macaques of both sexes on antiretroviral therapy (ART). In some macaques, anti–PD-1 CAR T cells expanded and persisted concomitant with the depletion of PD-1+ memory T cells—including lymph node CD4+ follicular helper T cells—associated with depletion of SIV RNA from the germinal center. Following CAR T infusion and ART interruption, SIV replication increased in extrafollicular portions of lymph nodes, plasma viremia was higher, and disease progression accelerated, indicating that anti–PD-1 CAR T cells depleted PD-1+ T cells and eradicated SIV from this immunological sanctuary. Supported by ORIP (U42OD011123, U42OD010426, P51OD010425, P51OD011092), NCI, NIAID, and NIDDK.
Timing of Initiation of Anti-Retroviral Therapy Predicts Post-Treatment Control of SIV Replication
Pinkevych et al., PLOS Pathogens. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10558076/
Researchers are interested in approaches to reducing viral rebound following interruption of antiretroviral therapy, but more work is needed to understand major factors that determine the viral “setpoint” level. Researchers previously assessed how timing of treatment can affect the frequency of rebound from latency. In the current study, the authors analyzed data from multiple studies of simian immunodeficiency virus (SIV) infection in rhesus macaques to further explore the dynamics and predictors of post-treatment viral control. They determined that the timing of treatment initiation was a major predictor of both the level and the duration of post-rebound SIV control. These findings could help inform future treatments. Supported by ORIP (U42OD011023, P51OD011132, P51OD011092), NIAID, NCI, NIDA, NIDDK, NHLBI, NIMH, and NINDS
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.
Promoting Validation and Cross-Phylogenetic Integration in Model Organism Research
Cheng et al., Disease Models & Mechanisms. 2022.
https://www.doi.org/10.1242/dmm.049600
Model organisms are essential for biomedical research and therapeutic development, but translation of such research to the clinic is low. The authors summarized discussions from an NIH virtual workshop series, titled “Validation of Animal Models and Tools for Biomedical Research,” held from 2020 to 2021. They described challenges and opportunities for developing and integrating tools and resources and provided suggestions for improving the rigor, validation, reproducibility, and translatability of model organism research. Supported by ORIP (R01OD011116, R24OD031447, R03OD030597, R24OD018559, R24OD017870, R24OD026591, R24OD022005, U42OD026645, U42OD012210, U54OD030165, UM1OD023221, P51OD011107), NIAMS, NIDDK, NIGMS, NHGRI, and NINDS.
Cannabinoid Control of Gingival Immune Activation in Chronically SIV-Infected Rhesus Macaques Involves Modulation of the Indoleamine-2,3-Dioxygenase-1 Pathway and Salivary Microbiome
McDew-White et al., EBioMedicine. 2021.
https://pubmed.ncbi.nlm.nih.gov/34954656/
HIV-associated periodontal disease (PD) affects people living with HIV (PLWH) on combination anti-retroviral therapy (cART). Researchers used a systems biology approach to investigate the molecular, metabolome, and microbiome changes underlying PD and its modulation by phytocannabinoids (Δ9-THC) in rhesus macaques. Δ9-THC reduced IDO1 protein expression. The findings suggest that phytocannabinoids may help reduce gingival/systemic inflammation, salivary dysbiosis, and potentially metabolic disease in PLWH on cART. Supported by ORIP (P51OD011104, P51OD011133, U42OD010442), NIAID, NIDA, NIDDK, NIDCR, and NIMH.