Selected Grantee Publications
Systematic Ocular Phenotyping of 8,707 Knockout Mouse Lines Identifies Genes Associated With Abnormal Corneal Phenotypes
Vo et al., BMC Genomics. 2025.
https://pubmed.ncbi.nlm.nih.gov/39833678
Corneal dysmorphologies (CDs) are a group of acquired but predominantly genetically inherited eye disorders that cause progressive vision loss and can be associated with systemic abnormalities. This study aimed to identify candidate CD genes in humans by looking at knockout mice with targeted deletions of orthologous genes that exhibited statistically significant corneal abnormalities. Analysis of data from 8,707 knockout mouse lines identified 213 candidate CD genes; 176 (83%) genes have not been implicated previously in CD. Bioinformatic analyses implicated candidate genes in several signaling pathways (e.g., integrin signaling pathway, cytoskeletal regulation by Rho GTPase, FAS signaling pathway), which are potential therapeutic targets. Supported by ORIP (U42OD011175, R03OD032622, UM1OD023221), NEI, and NHGRI.
The Widely Used Ucp1-Cre Transgene Elicits Complex Developmental and Metabolic Phenotypes
Halurkar et al., Nature Communications. 2025.
https://pubmed.ncbi.nlm.nih.gov/39824816
Bacterial artificial chromosome technology is instrumental to mouse transgenics, including in studies of highly thermogenic brown adipose tissue and energy-storing white adipose tissue. Researchers discovered that male and female Ucp1-CreEvdr transgenic mice, which are commonly used to study fat tissue, may have unintended effects on metabolism and development. Findings revealed that these mice show changes in both brown and white fat function and disruptions in gene activity, suggesting broader physiological impacts than previously thought. This study emphasizes the need for careful validation of genetic tools in research to ensure accurate results, highlighting the potential concerns in using the Ucp1-CreEvdr model in metabolic and developmental studies. Supported by ORIP (R21OD034470, R21OD031907) NCATS, NIDCR, and NIDDK.
Elevated Inflammation Associated With Markers of Neutrophil Function and Gastrointestinal Disruption in Pilot Study of Plasmodium fragile Co-Infection of ART-Treated SIVmac239+ Rhesus Macaques
Nemphos et al., Viruses. 2024.
https://pubmed.ncbi.nlm.nih.gov/39066199/
Because of geographic overlap, a high potential exists for co-infection with HIV and malaria caused by Plasmodium fragile. Meta-analysis of data collected from 1991 to 2018 demonstrated co-incidence of these two infections to be 43%. Researchers used a male rhesus macaque (RM) model, 6–12 years of age, coinfected with P. fragile and antiretroviral (ART)-treated simian immunodeficiency virus (SIV) to mimic HIV/malaria co-infection observed in patients. ART-treated co-infected RMs demonstrated increased levels of inflammatory cytokines, shifts in neutrophil function, and gastrointestinal mucosal dysfunction. This model may be used to study molecular mechanisms of disease pathology and novel therapies, such as neutrophil-targeted interventions, for patients experiencing co-infection. Supported by ORIP (U42OD010568, U42OD024282, P51OD011104, R21OD031435) and NIGMS.
Proinflammatory Cytokines Suppress Stemness-Related Properties and Expression of Tight Junction in Canine Intestinal Organoids
Nakazawa et al., In Vitro Cellular & Developmental Biology—Animal. 2024.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11419940
Cells in the gastrointestinal tract are exposed to numerous stressors that can promote excessive inflammation, including environmental chemicals and dietary substances. Researchers studied how canine intestinal epithelial cell (IEC)–derived organoids responded to exposure to one of three proinflammatory cytokines; interferon-γ (IFN-γ), tumor necrosis factor-α (TNFα), or interleukin-1β (IL1β). Exposure to IFN-γ resulted in downregulation of the stem cell marker Lgr5. Only IFN-γ exposure resulted in increased production of caspase 3 and caspase 8. Exposure to either IFN-γ or IL1β resulted in suppressed cell proliferation. The pro-inflammatory cytokines caused reduced tight junction protein expression and compromised membrane integrity. These findings are important to understanding IEC response to different inflammatory stimuli and to broadening knowledge of gut physiology. Supported by ORIP (K01OD030515, R21OD031903).
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).
Enterohemorrhagic Escherichia coli (EHEC) Disrupts Intestinal Barrier Integrity in Translational Canine Stem Cell-Derived Monolayers
Nagao et al., Microbiology Spectrum. 2024.
https://pubmed.ncbi.nlm.nih.gov/39162490/
EHEC produces Shiga toxin, which causes acute colitis with symptoms such as hemolytic uremic syndrome and bloody diarrhea. The researchers developed a colonoid-derived monolayer model to understand EHEC’s impact on canine gut health. Colonoid-derived monolayers co-cultured with EHEC demonstrated key differences compared with the control and nonpathogenic E. coli co-cultures. Scanning electron microscopy displayed EHEC aggregated and attached to the microvilli. EHEC-infected monolayers demonstrated significantly weakened membrane integrity and increased inflammatory cytokine production, specifically TNFα. The researchers developed a novel in vitro model that offers an additional platform for understanding the mechanisms of EHEC pathogenicity, developing therapeutics for EHEC, and studying additional enteric pathogens. Supported by ORIP (K01OD030515, R21OD031903).
Commentary: The International Mouse Phenotyping Consortium: High-Throughput In Vivo Functional Annotation of the Mammalian Genome
Lloyd, Mammalian Genome. 2024.
https://pubmed.ncbi.nlm.nih.gov/39254744
The International Mouse Phenotyping Consortium (IMPC), a collectively governed consortium of 21 academic research institutions across 15 countries on 5 continents, represents a groundbreaking approach in genetics and biomedical research. Its goal is to create a comprehensive catalog of mammalian gene function that is freely available and equally accessible to the global research community. So far, the IMPC has uncovered the function of thousands of genes about which little was previously known. By 2027, when the current round of funding expires, the IMPC will have produced and phenotyped nearly 12,000 knockout mouse lines representing approximately 60% of the human orthologous genome in mice. This new knowledge has produced numerous insights about the role of genes in health and disease, including informing the genetic basis of rare diseases and positing gene product influences on common diseases. However, as IMPC nears the end of the current funding cycle, its path forward remains unclear. Supported by ORIP (UM1OD023221).
Intrinsic Link Between PGRN and GBA1 D409V Mutation Dosage in Potentiating Gaucher Disease
Lin et al., Human Molecular Genetics. 2024.
https://doi.org/10.1093/hmg/ddae113
Gaucher disease (GD) is an autosomal recessive disorder and one of the most common lysosomal storage diseases. GD is caused by mutations in the GBA1 gene that encodes glucocerebrosidase (GCase), a lysosomal protein involved in glyocolipid metabolism. Progranulin (PGRN, encoded by GRN) is a modifier of GCase, and GRN mutant mice exhibit a GD-like phenotype. The researchers in this study aimed to understand the relationship between GCase and PGRN. They generated a panel of mice with various doses of the GBA1 D409V mutation in the GRN-/- background and characterized the animals’ disease progression using biochemical, pathological, transcriptomic, and neurobehavioral analyses. Homozygous (GRN-/-, GBA1 D409V/D409V) and hemizygous (GRN-/-, GBA1 D409V/null) animals exhibited profound inflammation and neurodegeneration compared to PG96 wild-type mice. Compared to homozygous mice, hemizygous mice showed more profound phenotypes (e.g., earlier onset, increased tissue fibrosis, shorter life span). These findings offer insights into GD pathogenesis and indicate that GD severity is affected by GBA1 D409V dosage and the presence of PGRN. Supported by ORIP (R21OD033660) and NINDS.
Validity of Xiphophorus Fish as Models for Human Disease
Schartl and Lu, Disease Models and Mechanisms. 2024.
https://pubmed.ncbi.nlm.nih.gov/38299666/
Xiphophorus is the one of the oldest animal systems for studying melanoma. In this article, the authors summarize current Xiphophorus models for other human diseases. They review how Xiphophorus fishes and their interspecies hybrids can be used for studying human diseases and highlight research opportunities enabled by these unique models (both established and emerging). They identified several emerging Xiphophorus models, including for albinism, micromelanophore pigmentation, fin regeneration, and diet-induced obesity. The research on cancer and reproductive maturation discussed in this review substantiates the value of Xiphophorus as a model for human disease throughout all three phases of validation—face, construct, and predictive—and continues to provide important scientific insights. Supported by ORIP (R24OD031467, R21OD031910) and NCI.
A Single-Cell Time-Lapse of Mouse Prenatal Development From Gastrula to Birth
Qiu et al., Nature. 2024.
https://pubmed.ncbi.nlm.nih.gov/38355799/
In this study, investigators combined single-cell transcriptome profiling of male and female mouse embryos and newborn pups with previously published data to construct a tree of cell-type relationships tracing development from zygote to birth. They applied optimized single-cell combinatorial indexing to profile the transcriptional states of 12.4 million nuclei from 83 embryos, precisely staged at 2- to 6-hour intervals spanning late gastrulation to birth; establish a global framework for exploring mammalian development; and construct a rooted tree of cell-type relationships, from zygote to birth. Their analysis allowed them to systematically nominate genes that encode transcription factors and other proteins as candidate drivers of the in vivo differentiation of hundreds of cell types. Extending this framework to postnatal time points could yield a single-cell time-lapse of the entire mammalian life span, from conception to death. Supported by ORIP (UM1OD023222) and NHGRI.