Selected Grantee Publications
Extended Survival of 9- and 10-Gene-Edited Pig Heart Xenografts With Ischemia Minimization and CD154 Costimulation Blockade-Based Immunosuppression
Chaban et al., The Journal of Heart and Lung Transplantation. 2024.
https://pubmed.ncbi.nlm.nih.gov/39097214
Heart transplantations are severely constrained from the shortage of available organs derived from human donors. Xenotransplantation of hearts from gene-edited (GE) pigs is a promising way to address this problem. Researchers evaluated GE pig hearts with varying knockouts and human transgene insertions. Human transgenes are introduced to mitigate important physiological incompatibilities between pig cells and human blood. Using a baboon heterotopic cardiac transplantation model, one female and seven male specific-pathogen-free baboons received either a 3-GE, 9-GE, or 10-GE pig heart with an immunosuppression regimen targeting CD40/CD154. Early cardiac xenograft failure with complement activation and multifocal infarcts were observed with 3-GE pig hearts, whereas 9- and 10-GE pig hearts demonstrated successful graft function and prolonged survival. These findings show that one or more transgenes of the 9- and 10-GE pig hearts with CD154 blockade provide graft protection in this preclinical model. Supported by ORIP (U42OD011140) and NIAID.
Engineered Deletions of HIV Replicate Conditionally to Reduce Disease in Nonhuman Primates
Pitchai et al., Science. 2024.
https://pubmed.ncbi.nlm.nih.gov/39116226/
Current antiretroviral therapy (ART) for HIV is limited by the necessity for continuous administration. Discontinuation of ART leads to viral rebound. A therapeutic interfering particle (TIP) was developed as a novel single-administration HIV therapy using defective interfering particles. TIP treatment in two humanized mouse models demonstrated a significant reduction in HIV viral load. TIP intervention was completed 24 hours prior to a highly pathogenic simian immunodeficiency virus (SIV) challenge in a nonhuman primate (NHP) rhesus macaque infant model. Compared to untreated SIV infection, NHPs that received TIP treatment displayed no visible signs of SIV-induced AIDS and exhibited improved seroconversion and a significant survival advantage to the 30-week clinical endpoint. Peripheral blood mononuclear cells isolated from HIV-infected patients showed that TIP treatment reduced HIV outgrowth. This study demonstrates the potential use of a single-administration TIP for HIV treatment. Supported by ORIP (P51OD011092, U42OD010426), NCI, NIAID, and NIDA.
Fetal Bone Engraftment Reconstitutes the Immune System in Pigs With Severe Combined Immunodeficiency
Monarch et al., Lab Animal. 2024.
https://pubmed.ncbi.nlm.nih.gov/39289566/
A valuable preclinical model for studying immune-related pathologies is the severe combined immunodeficiency (SCID) pig through modification of recombination activating gene 2 (RAG2) and interleukin-2 receptor-γ (IL2RG). RAG2/IL2RG double knockout SCID pigs are hard to maintain for breeding and long-term studies because their life span is 8 weeks or less. The researchers investigated fetal allograft transplantation derived from immunocompetent pigs as a strategy for reconstituting the immune system of SCID pigs and promoting survival. Following fetal allograft, SCID pigs demonstrated increased levels of lymphocytes. SCID pigs that received the fetal allograft demonstrated improved body condition and extended life span compared with nonrecipient SCID littermates. This study demonstrates the potential use of fetal allograft transplantation to extend the life span of SCID pigs to breeding age to reduce the resources used to maintain this model for biomedical research. Supported by ORIP (U42OD011140, R21OD027062).
Impaired Skeletal Development by Disruption of Presenilin-1 in Pigs and Generation of Novel Pig Models for Alzheimer's Disease
Uh et al., Journal of Alzheimer's Disease. 2024.
https://pubmed.ncbi.nlm.nih.gov/39177593/
This study explored the effects of presenilin 1 (PSEN1) disruption on vertebral malformations in male and female PSEN1 mutant pigs. Researchers observed significant skeletal impairments and early deaths in pigs with a PSEN1 null mutation, mirroring phenotypes seen in mouse models of Alzheimer’s disease (AD). This porcine model provides valuable insights into pathological hallmarks of PSEN1 mutations in AD, offering a robust platform of therapeutic exploration. The findings establish pigs as an essential translational model for AD, enabling advanced studies on pathophysiology and treatment development for human skeletal and neurological conditions. Supported by ORIP (U42OD011140), NHLBI, NIA, NIAID.
Gene Editing of Pigs to Control Influenza A Virus Infections
Kwon et al., Emerging Microbes & Infections. 2024.
https://pubmed.ncbi.nlm.nih.gov/39083026/
A reduction in the efficacy of vaccines and antiviral drugs for combating infectious diseases in agricultural animals has been observed. Generating genetically modified livestock species to minimize susceptibility to infectious diseases is of interest as an alternative approach. The researchers developed a homozygous transmembrane serine protease 2 (TMPRSS2) knockout (KO) porcine model to investigate resistance to two influenza A virus (IAV) subtypes, H1N1 and H3N2. TMPRSS2 KO pigs demonstrated diminished nasal cavity viral shedding, lower viral burden, and reduced microscopic lung pathology compared with wild-type (WT) pigs. In vitro culturing of primary bronchial epithelial cells (PBECs) demonstrated delayed viral replication in TMPRSS2 KO pigs compared with WT pigs. This study demonstrates the potential use of genetically modified pigs to mitigate IAV infections in pigs and limit transmission to humans. Supported by ORIP (U42OD011140), NHLBI, NIAID, and NIGMS.
Bone Marrow Transplantation Increases Sulfatase Activity in Somatic Tissues in a Multiple Sulfatase Deficiency Mouse Model
Presa et al., Communications Medicine. 2024.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11502872/pdf/43856_2024_Article_648.pdf
Multiple Sulfatase Deficiency (MSD) is a rare genetic disorder where patients demonstrate loss of function mutations in the SUMF1 gene, resulting in a severe reduction in sulfatase activity. This enzyme deficiency causes impaired lysosomal function and widespread inflammation, leading to clinical manifestations like neurodegeneration, vision and hearing loss, and cardiac disease. The researchers evaluated the therapeutic potential of hematopoietic stem cell transplant (HSCT) to initiate cross-correction, where functional sulfatase enzymes secreted from the healthy donor cells are taken up to restore function in enzyme-deficient host cells. Bone marrow from healthy male and female B6-Sumf1(+/+) mice were transplanted into B6-Sumf1(S153P/S153P) mice, a model for MSD. The results showed that HSCT is suitable to rescue sulfatase activity in peripheral organs, such as the liver, spleen, and heart, but is not beneficial alone in inhibiting the central nervous system pathology of MSD. Supported by ORIP (U54OD020351, U54OD030187, U42OD010921) and NCI.
Comparison of the Immunogenicity of mRNA-Encoded and Protein HIV-1 Env-ferritin Nanoparticle Designs
Mu et al., Journal of Virology. 2024.
https://journals.asm.org/doi/10.1128/jvi.00137-24
Inducing broadly neutralizing antibodies (bNAbs) against HIV-1 remains a challenge because of immune system limitations. This study compared the immunogenicity of mRNA-encoded membrane-bound envelope (Env) gp160 to HIV-1 Env-ferritin nanoparticle (NP) technology in inducing anti-HIV-1 bNAbs. Membrane-bound mRNA encoding gp160 was more immunogenic than the Env-ferritin NP design in DH270 UCA KI mice, but at lower doses. These results suggest further analysis of mRNA design expression and low-dose immunogenicity studies are necessary for anti-HIV-1 bNAbs. Supported by ORIP (P40OD012217, U42OD021458) and NIAID.
The Mutant Mouse Resource and Research Center (MMRRC) Consortium: The U.S.-Based Public Mouse Repository System
Agca et al., Mammalian Genome. 2024.
https://link.springer.com/article/10.1007/s00335-024-10070-3
The MMRRC has been the nation’s preeminent public repository and distribution archive of mutant mouse models for 25 years. The Consortium, with support from NIH, facilitates biomedical research by identifying, acquiring, evaluating, characterizing, preserving, and distributing a variety of mutant mouse strains to investigators around the world. Since its inception, the MMRRC has fulfilled more than 20,000 orders from 13,651 scientists at 8,441 institutions worldwide. Today, the MMRRC maintains an archive of mice, cryopreserved embryos and sperm, embryonic stem-cell lines, and murine monoclonal antibodies for nearly 65,000 alleles. The Consortium also provides scientific consultation, technical assistance, genetic assays, microbiome analysis, analytical phenotyping, pathology, husbandry, breeding and colony management, and more. Supported by ORIP (U42OD010918, U42OD010924, U42OD010983).
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.
RNA Landscapes of Brain and Brain-Derived Extracellular Vesicles in Simian Immunodeficiency Virus Infection and Central Nervous System Pathology
Huang et al., The Journal of Infectious Diseases. 2024.
https://pubmed.ncbi.nlm.nih.gov/38079216/
Brain tissue–derived extracellular vesicles (bdEVs) act locally in the central nervous system (CNS) and may indicate molecular mechanisms in HIV CNS pathology. Using brain homogenate (BH) and bdEVs from male pigtailed macaques, researchers identified dysregulated RNAs in acute and chronic infection. Most dysregulated messenger RNAs (mRNAs) in bdEVs reflected dysregulation in source BH, and these mRNAs are disproportionately involved in inflammation and immune responses. Additionally, several circular RNAs were differentially abundant in source tissue and might be responsible for specific differences in small RNA levels in bdEVs during simian immunodeficiency virus (SIV) infection. This RNA profiling shows potential regulatory networks in SIV infection and SIV-related CNS pathology. Supported by ORIP (U42OD013117), NCI, NIAID, NIDA, NIMH, and NINDS.