Selected Grantee Publications
Age-Associated DNA Methylation Changes in Xenopus Frogs
Morselli et al., Epigenetics. 2023.
https://www.tandfonline.com/doi/full/10.1080/15592294.2023.2201517
Age-associated changes in DNA methylation have not been characterized yet in amphibians, which include widely studied model organisms. Here the authors present clear evidence that the aquatic vertebrate species Xenopus tropicalis displays patterns of age-associated changes in DNA methylation. Whole-genome bisulfite sequencing profiles from skin samples of frogs representing young, mature, and old adults demonstrated that many of the methylation features and changes they observed are consistent with what is known in mammalian species, suggesting that the mechanism of age-related changes is conserved. The results of this study will allow researchers to leverage the unique resources available for Xenopus to study how DNA methylation relates to other hallmarks of aging. Supported by ORIP (P40OD010997, R24OD031956, R24OD030008) and NICHD.
Prime Editing–Mediated Correction of the CFTR W1282X Mutation in iPSCs and Derived Airway Epithelial Cells
Li et al., PLOS ONE. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10686454/
Cystic fibrosis (CF) is caused by recessive mutations in the CF transmembrane conductance regulator (CFTR) gene. Correction of nonsense CFTR mutations, which affects 10% of CF patients, via genomic editing represents a promising therapeutic approach. In this study, investigators tested whether prime editing can be applied as a potential therapeutic modality. Induced pluripotent stem cells (iPSCs) from a CF patient homozygous for the CFTR W1282X mutation were used. Studies demonstrated that prime editing corrected mutant allele in iPSCs, which effectively restored CFTR function in iPSC-derived airway epithelial cells and organoids. Supported by ORIP (R01OD01026594).
Broad Receptor Tropism and Immunogenicity of a Clade 3 Sarbecovirus
Lee et al., Cell Host and Microbe. 2023.
https://www.sciencedirect.com/science/article/pii/S1931312823004225
Investigators showed that the S glycoprotein of the clade 3 sarbecovirus PRD-0038 in the African Rhinolophus bat has a broad angiotensin-converting enzyme 2 (ACE2) usage and that receptor-binding domain (RBD) mutations further expand receptor promiscuity and enable human ACE2 utilization. They generated a cryogenic electron microscopy structure of the RBD bound to ACE2, explaining receptor tropism and highlighting differences between SARS-CoV-1 and SARS-CoV-2. PRD‑0038 S vaccination elicits greater titers of antibodies cross-reacting with vaccine-mismatched clade 2 and clade 1a sarbecoviruses, compared with SARS-CoV-2. These findings underline a potential molecular pathway for zoonotic spillover of a clade 3 sarbecovirus, as well as the need to develop pan-sarbecovirus vaccines and countermeasures. Supported by ORIP (S10OD032290, S10OD026959, S10OD021644), NIAID, NCI, and NIGMS.
DAZL Knockout Pigs as Recipients for Spermatogonial Stem Cell Transplantation
Lara et al., Cells. 2023.
https://pubmed.ncbi.nlm.nih.gov/37947660/
Spermatogonial stem cell (SSC) transplantation is a technique that holds potential for addressing male infertility, as well as generation of genetically modified animal models. DAZL (Deleted in Azoospermia–Like) is a conserved RNA-binding protein important for germ cell development, and DAZL knockout (KO) causes defects in germ cell commitment and differentiation. Investigators characterized DAZL-KO pigs as SSC transplantation recipients. DAZL-KO pigs support donor-derived spermatogenesis following SSC transplantation, but low spermatogenic efficiency currently limits their use for the production of offspring. Supported by ORIP (R01OD016575) and NIGMS.
The Power of the Heterogeneous Stock Rat Founder Strains in Modeling Metabolic Disease
Wagner et al., Endocrinology. 2023.
https://pubmed.ncbi.nlm.nih.gov/37882530/
Metabolic diseases are a host of complex conditions, including obesity, diabetes mellitus, and metabolic syndrome. Endocrine control systems (e.g., adrenals, thyroid, gonads) are causally linked to metabolic health outcomes. In this study, investigators determined novel metabolic and endocrine health characteristics in both sexes of six available substrains similar to the N/NIH Heterogeneous Stock (HS) rat founders. This deep-phenotyping protocol provides new insight into the exceptional potential of the HS rat population to model complex metabolic health states. The following hypothesis was tested: The genetic diversity in the HS rat founder strains represents a range of endocrine health conditions contributing to the diversity of cardiometabolic disease risks exhibited in the HS rat population. Supported by ORIP (R24OD024617), NHLBI, NIGMS and NIDDK.
Global Frequency Analyses of Canine Progressive Rod-Cone Degeneration-Progressive Retinal Atrophy and Collie Eye Anomaly Using Commercial Genetic Testing Data
Clark et al., Genes (Basel). 2023.
https://pubmed.ncbi.nlm.nih.gov/38003037/
Hundreds of genetic variants associated with canine traits and disorders have been identified; however, the geographic distributions and changes in allele and genotype frequencies over prolonged, continuous periods of time are lacking. This study utilized a large set of genotypes from dogs tested for progressive rod-cone degeneration-progressive retinal atrophy (prcd‑PRA) and collie eye anomaly (CEA). Both diseases exhibited significant differences in genotype frequencies (p=2.7 × 10-152 for prcd-PRA and 0.023 for CEA) with opposing graphical trends. This study shows that genetic testing informed breeding decisions to produce fewer affected dogs. Supported by ORIP (K01OD027051).
A SACS Deletion Variant in Great Pyrenees Dogs Causes Autosomal Recessive Neuronal Degeneration
Ekenstedt et al., Human Genetics. 2023.
https://pubmed.ncbi.nlm.nih.gov/37758910/
ARSACS (autosomal recessive spastic ataxia of Charlevoix-Saguenay) is an early-onset, slowly progressive neurodegenerative disorder. To date, no naturally occurring large animal model has been reported for ARSACS. In this study, the authors describe a novel spontaneous genetic model for SACS-associated neuronal degeneration using Great Pyrenees dogs of both sexes. The canine models described in this study fit closely with the typical early‑onset ARSACS phenotype in humans, and molecular genetic studies demonstrated that these dogs exhibit a deleterious SACS mutation. The clinical and histopathological descriptions of this canine disorder contribute to the description of human ARSACS. Supported by ORIP (R01OD01027051).
HIV-1 Remission: Accelerating the Path to Permanent HIV-1 Silencing
Lyons et al., c. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10674359/
Current HIV treatment strategies are focused on forced proviral reactivation and elimination of reactivated cells with immunological or toxin-based technologies. Researchers have proposed the use of a novel “block-lock-stop” approach, which entails the long-term durable silencing of viral expression and permanent transcriptional deactivation of the latent provirus. In the present study, the authors present this approach and its rationale. More research is needed to understand the (1) epigenetic architecture of integrated provirus, (2) cell types and epigenetic cell states that favor viral rebound, (3) molecular functions of Tat (a protein that controls transcription of HIV) and host factors that prevent permanent silencing, (4) human endogenous retrovirus silencing in the genome, and (5) approaches to generate defective proviruses. Additionally, community engagement is crucial for this effort. Supported by ORIP (K01OD031900), NIAID, NCI, NIDA, NIDDK, NHLBI, NIMH, and NINDS.
Allelic Strengths of Encephalopathy-Associated UBA5 Variants Correlate Between In Vivo and In Vitro Assays
Pan et al., eLife. 2023.
https://pubmed.ncbi.nlm.nih.gov/37502976/
The UBA5 gene is associated with developmental and epileptic encephalopathy 44 (DEE44), an autosomal recessive disorder, in humans. The link between UBA5 variants and severity of DEE44, however, is not established. Investigators developed humanized fly models carrying a series of patient UBA5 variants. These flies showed differences in survival rates, developmental progress, life span, and neurological well-being. The severity of these defects correlated strongly with functional defects of UBA5 variants, allowing the classification of UBA5 loss-of-function variants into mild, intermediate, and severe allelic strengths in patients. This study provides resources for systematic investigation of the mechanistic link between UBA5 variants and DEE44 and for developing diagnostic approaches. Supported by ORIP (R24OD022005, R24OD031447, U54OD035865) and NCATS.
Interferon Regulatory Factor 7 Modulates Virus Clearance and Immune Responses to Alphavirus Encephalomyelitis
Troisi et al., Journal of Virology. 2023.
https://pubmed.ncbi.nlm.nih.gov/37772825/
Interferon regulatory factor 7 (IRF7)–deficient mice develop fatal paralysis after CNS infection with Sindbis virus, while wild-type mice recover. Irf7-/- mice produce low levels of IFN-α but high levels of IFN-β with induction of IFN-stimulated genes, so the reason for this difference is not understood. The current study shows that Irf7-/- mice developed inflammation earlier but failed to clear virus from motor neuron–rich regions of the brainstem and spinal cord. Therefore, IRF7 is either necessary for the neuronal response to currently identified mediators of clearance or enables the production of additional antiviral factor(s) needed for clearance. Supported by ORIP (T32OD011089, R01OD01026529) NINDS, and NIAID.