Selected Grantee Publications
Consistent Survival in Consecutive Cases of Life-Supporting Porcine Kidney Xenotransplantation Using 10GE Source Pigs
Eiseson et al., Nature Communications. 2024.
https://pubmed.ncbi.nlm.nih.gov/38637524/
Xenotransplantation offers potential for addressing organ donor shortages, and the U.S. Food and Drug Administration recently issued guidance on a regulatory path forward. Researchers have performed studies in this area, but concerns have been expressed about safe clinical translation of their results (e.g., survival, preclinical procurement, immunosuppression, clinical standards of care). In this study, the authors report consistent survival in consecutive cases of kidney xenotransplantation from pigs (male and female) to baboons (male and female). The authors propose that their findings serve as proof of concept for prevention of xenograft rejection in recipients of genetically modified porcine kidneys. This work offers insights for immunosuppression regimens for first-in-human clinical trials. Supported by ORIP (P40OD024628).
Induction of Durable Remission by Dual Immunotherapy in SHIV-Infected ART-Suppressed Macaques
Lim et al., Science. 2024.
https://pubmed.ncbi.nlm.nih.gov/38422185/
The latent viral reservoir is established within the first few days of HIV infection and remains a barrier to a clinical cure. Researchers characterized the effects of a combined Anktiva (N-803) treatment with broadly neutralizing antibodies (bNAbs) using male and female rhesus macaques infected with simian–human immunodeficiency virus infection. Their data suggest that these agents synergize to enhance CD8+ T-cell function, particularly when multiple bNAbs are used. Taken together, this work indicates that immune-mediated control of viral rebound is not a prerequisite for sustained remission after discontinuation of antiretroviral therapy and that immune-mediated control of viral rebound is achievable, sufficient, and sustainable in this model. Supported by ORIP (P51OD011106, P40OD028116, R24OD011195) and NIAID.
Trade-Offs Shaping Transmission of Sylvatic Dengue and Zika Viruses in Monkey Hosts
Hanley et al., Nature Communications. 2024.
https://pubmed.ncbi.nlm.nih.gov/38538621/
Mosquito-borne dengue (DENV) and Zika (ZIKV) viruses originated in Old World sylvatic (forest) cycles involving monkeys and canopy-living Aedes mosquitoes. Both viruses spilled over into human transmission and were translocated to the Americas, opening a path for spillback into neotropical sylvatic cycles. This article reports that the trade-offs that shape within-host dynamics and transmission of these viruses are lacking, hampering efforts to predict spillover and spillback. The data revealed evidence of an immunologically mediated trade‑off between duration and magnitude of virus replication, as higher-peak ZIKV titers are associated with shorter durations of viremia, and higher natural killer cell levels are associated with lower peak ZIKV titers and lower anti-DENV-2 antibody levels. Furthermore, patterns of transmission of each virus from a neotropical monkey suggest that ZIKV has greater potential than DENV-2 to establish a sylvatic transmission cycle in the Americas. Supported by ORIP (P40OD010938) and NIAID.
Pigs in Transplantation Research and Their Potential as Sources of Organs in Clinical Xenotransplantation
Raza et al., Comparative Medicine. 2024.
https://pubmed.ncbi.nlm.nih.gov/38359908/
The pig has now gained importance as a potential source of organs for clinical xenotransplantation. When an organ from a wild-type (i.e., genetically unmodified) pig is transplanted into an immunosuppressed nonhuman primate, a vigorous host immune response causes hyperacute rejection (within minutes or hours). This response has been largely overcome by (1) extensive gene editing of the organ-source pig and (2) administration to the recipient of novel immunosuppressive therapy based on blockade of the CD40/CD154 T-cell costimulation pathway. The combination of gene editing and novel immunosuppressive therapy has extended life-supporting pig kidney graft survival to greater than 1 year and of pig heart survival to up to 9 months. This review briefly describes the techniques of gene editing, the potential risks of transfer of porcine endogenous retroviruses with the organ, and the need for breeding and housing of donor pigs under biosecure conditions. Supported by ORIP (P40OD024628) and NIAID.
Epigenetic MLH1 Silencing Concurs With Mismatch Repair Deficiency in Sporadic, Naturally Occurring Colorectal Cancer in Rhesus Macaques
Deycmar et al., Journal of Translational Medicine. 2024.
https://pubmed.ncbi.nlm.nih.gov/38504345
Rhesus macaques serve as a useful model for colorectal cancer (CRC) in humans, but more data are needed to understand the molecular pathogenesis of these cancers. Using male and female rhesus macaques, researchers investigated mismatch repair status, microsatellite instability, genetic mutations, transcriptional differences, and epigenetic alterations associated with CRC. Their data indicate that epigenetic silencing suppresses MLH1 transcription, induces the loss of MLH1 protein, abrogates mismatch repair, and drives genomic instability in naturally occurring CRC in rhesus macaques. This work provides a uniquely informative model for human CRC. Supported by ORIP (P51OD011092, R24OD010947, R24OD021324, P40OD012217, U42OD010426, T35OD010946, T32OD010957), NCATS, and NCI.
Injury-Induced Cooperation of InhibinβA and JunB is Essential for Cell Proliferation in Xenopus Tadpole Tail Regeneration
Nakamura et al., Scientific Reports. 2024.
https://pubmed.ncbi.nlm.nih.gov/38355764/
Certain animal species (e.g., amphibians) that can regenerate lost tissues and limbs after injury offer potential for applications in regenerative medicine. Cell proliferation is essential for the reconstruction of injured tissue, but the molecular mechanisms that regulate the transition from wound healing to regenerative cell proliferation remain unclear. Using Xenopus tropicalis, investigators examined the effects of injury on the expression of inhibin subunit beta A (inhba) and junB proto-oncogene (junb). Their findings shed light on the mechanisms underlying injury-induced cell proliferation in regenerative animals. Supported by ORIP (P40OD010997, R24OD030008).
Identification of Constrained Sequence Elements Across 239 Primate Genomes
Kuderna et al., Nature. 2024.
https://pubmed.ncbi.nlm.nih.gov/38030727/
Functional genomic elements that have acquired selective constraints specific to the primate order are prime candidates for understanding evolutionary changes in humans, but the selective constraints specific to the phylogenetic branch from which the human species ultimately emerged remain largely unidentified. Researchers constructed a genome-wide multiple sequence alignment of 239 primate species to better characterize constraint at noncoding regulatory sequences in the human genome. Their work reveals noncoding regulatory elements that are under selective constraint in primates but not in other placental mammals and are enriched for variants that affect human gene expression and complex traits in diseases. These findings highlight the important role of recent evolution in regulatory sequence elements differentiating primates, including humans, from other placental mammals. Supported by ORIP (P40OD024628), NHGRI, NIA, and NICHD.
GenomeMUSter Mouse Genetic Variation Service Enables Multitrait, Multipopulation Data Integration and Analysis
Ball et al., Genome Research. 2024.
https://genome.cshlp.org/content/34/1/145.long
Advances in genetics, including transcriptome-wide and phenome-wide association analysis methods, create compelling new opportunities for using fully reproducible and widely studied inbred mouse strains to characterize the polygenetic basis for individual differences in disease-related traits. Investigators developed an imputation approach and implemented data service to provide a broad and more comprehensive mouse variant resource. They evaluated the strain-specific imputation accuracy on a “held-out” test set that was not used in the imputation process. The authors present its application to multipopulation and multispecies analyses of complex trait variation in type 2 diabetes and substance use disorders and compare these results to human genetics studies. Supported by ORIP (U42OD010921, P40OD011102, R24OD035408), NCI, NIAAA, NIDA, and NIDCD.
Preclinical Safety and Biodistribution of CRISPR Targeting SIV in Non-Human Primates
Burdo et al., Gene Therapy. 2024.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11090835/
Nonhuman primates have served as a valuable resource for evaluating novel eradication and cure strategies for HIV infection. Using a male rhesus macaque model, researchers demonstrated the safety and utility of CRISPR gene-editing technology for targeting integrated simian immunodeficiency virus (SIV). Their work suggests that a single intravenous inoculation for HIV gene editing can be utilized to reach viral reservoirs throughout the body. Additionally, no off-target effects or abnormal pathology were observed. Together, these findings support the continued development of HIV eradicative cure strategies using CRISPR technology in humans. Supported by ORIP (P40OD012217, U42OD021458).
Establishment of a Practical Sperm Cryopreservation Pathway for the Axolotl (Ambystoma mexicanum): A Community-Level Approach to Germplasm Repository Development
Coxe et al., Animals (Basel). 2024.
https://pubmed.ncbi.nlm.nih.gov/38254376/
The axolotl (Ambystoma mexicanum) is an important biomedical research model for organ regeneration, but housing and maintaining live animals is expensive and risky as new transgenic lines are developed. The authors report an initial practical pathway for sperm cryopreservation to support germplasm repository development. They assembled a pathway through the investigation of axolotl sperm collection by stripping, refrigerated storage in various osmotic pressures, cryopreservation in various cryoprotectants, and in vitro fertilization using thawed sperm. This work is the first report of successful production of axolotl offspring with cryopreserved sperm and provides a general framework for pathway development to establish Ambystoma germplasm repositories for future research and applications. Supported by ORIP (R24OD010441, R24OD028443, P40OD019794).