Resistin-like molecule γ attacks cardiomyocyte membranes and promotes ventricular tachycardia.

Ventricular tachycardia disrupts the heart's coordinated pump function, leading to sudden cardiac death. Neutrophils, which are recruited in high numbers to the ischemic myocardium, promote these arrhythmias. Comparing neutrophils with macrophages, we found that resistin-like molecule γ ( or RELMγ) was the most differentially expressed gene in mouse infarcts.

Sustained Lung Inflammation Post-SARS-CoV-2 Infection in Mice Is Associated with Increased Pulmonary T Cells.

Many SARS-CoV-2 patients experience chronic pulmonary symptoms and long-term inflammation despite viral clearance. While these clinical manifestations have been linked to the dysregulation of the adaptive immune response, the underlying immunopathology remains poorly understood due to a lack of suitable animal models. To investigate long-term pulmonary consequences of SARS-CoV-2 infection, we used a genetic cross of 129 mice and C57BL/6 (B6)-K18-hACE2 transgene mice, a model previously shown to survive infection.

Transcripts with high distal heritability mediate genetic effects on complex metabolic traits.

Although many genes are subject to local regulation, recent evidence suggests that complex distal regulation may be more important in mediating phenotypic variability. To assess the role of distal gene regulation in complex traits, we combine multi-tissue transcriptomes with physiological outcomes to model diet-induced obesity and metabolic disease in a population of Diversity Outbred mice. Using a novel high-dimensional mediation analysis, we identify a composite transcriptome signature that summarizes genetic effects on gene expression and explains 30% of the variation across all metabolic traits.

The rare-to-common disease journey: a winding road to new therapies.

The study of genetic variants that cause rare diseases has been a central strategy of genetic research for the last century, but the contribution of rare variants to the multifactorial inheritance of common diseases has only recently emerged as an avenue to accelerate functional mapping of the human genome. This perspective defines rare and common diseases, surveys prospects for integrating their study to decipher pathogenic mechanisms, and cites current clinical hurdles of disease translation. We discuss the premise that research into rare disease etiology can inform our understanding of common illnesses and vice versa, identify impediments to progress in translating rare disease findings into common disease treatments, and offer suggestions for realizing the benefits of global health research in the discovery of rare disease variants.

High-Throughput Echocardiography-Guided Induction of Myocardial Ischemia/Reperfusion in Mice.

Background: Mouse models of myocardial ischemia with subsequent heart failure are common approaches to examine heart failure pathology and possible treatment strategies. We sought to establish a high-throughput approach for echocardiography-guided induction of myocardial ischemia/reperfusion (IR) in mice.

Methods: After visualization of the left coronary artery with high-resolution ultrasound imaging and echocardiographic definition of the level of coronary occlusion, the left anterior descending artery was temporarily occluded with 2 micromanipulator-controlled needles.

Characterization of Collaborative Cross mouse founder strain CAST/EiJ as a novel model for lethal COVID-19.

Mutations in SARS-CoV-2 variants of concern (VOCs) have expanded the viral host range beyond primates, and a few other mammals, to mice, affording the opportunity to exploit genetically diverse mouse panels to model the broad spectrum of responses to infection in patient populations. Here we surveyed responses to VOC infection in genetically diverse Collaborative Cross (CC) founder strains. Infection of wild-derived CC founder strains produced a broad range of viral burden, disease susceptibility and survival, whereas most other strains were resistant to disease despite measurable lung viral titers.

Transcripts with high distal heritability mediate genetic effects on complex metabolic traits.

Although many genes are subject to local regulation, recent evidence suggests that complex distal regulation may be more important in mediating phenotypic variability. To assess the role of distal gene regulation in complex traits, we combined multi-tissue transcriptomes with physiological outcomes to model diet-induced obesity and metabolic disease in a population of Diversity Outbred mice. Using a novel high-dimensional mediation analysis, we identified a composite transcriptome signature that summarized genetic effects on gene expression and explained 30% of the variation across all metabolic traits.

Linking immune modulation to cardiac fibrosis.

On 21–23 September 2023, the Immuno-Cardiology Symposium was hosted by the Leducq Foundation Networks of Excellence Program (The Inflammatory-Fibrosis Axis in Adverse LV Remodeling: translating mechanisms into new diagnostics and therapeutics) at The Jackson Laboratory in Bar Harbor, Maine. The symposium highlighted recent advances in the basic science of dysregulated immune system activation and fibrosis in response to cardiac injury.

Characterization of Collaborative Cross mouse founder strain CAST/EiJ as a novel model for lethal COVID-19.

Mutations in SARS-CoV-2 variants of concern (VOCs) have expanded the viral host range beyond primates, and a limited range of other mammals, to mice, affording the opportunity to exploit genetically diverse mouse panels to model the broad range of responses to infection in patient populations. Here we surveyed responses to VOC infection in genetically diverse Collaborative Cross (CC) founder strains. Infection of wild-derived CC founder strains produced a broad range of viral burden, disease susceptibility and survival, whereas most other strains were resistant to disease despite measurable lung viral titers.

Revisiting Cardiac Biology in the Era of Single Cell and Spatial Omics.

Throughout our lifetime, each beat of the heart requires the coordinated action of multiple cardiac cell types. Understanding cardiac cell biology, its intricate microenvironments, and the mechanisms that govern their function in health and disease are crucial to designing novel therapeutical and behavioral interventions. Recent advances in single-cell and spatial omics technologies have significantly propelled this understanding, offering novel insights into the cellular diversity and function and the complex interactions of cardiac tissue.

Lifespan effects in male UM-HET3 mice treated with sodium thiosulfate, 16-hydroxyestriol, and late-start canagliflozin.

Genetically heterogeneous UM-HET3 mice born in 2020 were used to test possible lifespan effects of alpha-ketoglutarate (AKG), 2,4-dinitrophenol (DNP), hydralazine (HYD), nebivolol (NEBI), 16α-hydroxyestriol (OH_Est), and sodium thiosulfate (THIO), and to evaluate the effects of canagliflozin (Cana) when started at 16 months of age. OH_Est produced a 15% increase (p = 0.0001) in median lifespan in males but led to a significant (7%) decline in female lifespan.

Into the Wild: A novel wild-derived inbred strain resource expands the genomic and phenotypic diversity of laboratory mouse models.

The laboratory mouse has served as the premier animal model system for both basic and preclinical investigations for over a century. However, laboratory mice capture only a subset of the genetic variation found in wild mouse populations, ultimately limiting the potential of classical inbred strains to uncover phenotype-associated variants and pathways. Wild mouse populations are reservoirs of genetic diversity that could facilitate the discovery of new functional and disease-associated alleles, but the scarcity of commercially available, well-characterized wild mouse strains limits their broader adoption in biomedical research.

Unraveling the evolutionary origin of the complex Nuclear Receptor Element (cNRE), a cis-regulatory module required for preferential expression in the atrial chamber.

Cardiac function requires appropriate proteins in each chamber. Atria requires slow myosin to act as reservoirs, while ventricles demand fast myosin for swift pumping. Myosins are thus under chamber-biased cis-regulation, with myosin gene expression imbalances leading to congenital heart dysfunction.

Murine MHC-Deficient Nonobese Diabetic Mice Carrying Human HLA-DQ8 Develop Severe Myocarditis and Myositis in Response to Anti-PD-1 Immune Checkpoint Inhibitor Cancer Therapy.

Myocarditis has emerged as an immune-related adverse event of immune checkpoint inhibitor (ICI) cancer therapy associated with significant mortality. To ensure patients continue to safely benefit from life-saving cancer therapy, an understanding of fundamental immunological phenomena underlying ICI myocarditis is essential. We recently developed the NOD-cMHCI/II-/-.

Astaxanthin and meclizine extend lifespan in UM-HET3 male mice; fisetin, SG1002 (hydrogen sulfide donor), dimethyl fumarate, mycophenolic acid, and 4-phenylbutyrate do not significantly affect lifespan in either sex at the doses and schedules used.

In genetically heterogeneous (UM-HET3) mice produced by the CByB6F1 × C3D2F1 cross, the Nrf2 activator astaxanthin (Asta) extended the median male lifespan by 12% (p = 0.003, log-rank test), while meclizine (Mec), an mTORC1 inhibitor, extended the male lifespan by 8% (p = 0.03).

HLA-DQ8 Supports Development of Insulitis Mediated by Insulin-Reactive Human TCR-Transgenic T Cells in Nonobese Diabetic Mice.

In an effort to improve HLA-"humanized" mouse models for type 1 diabetes (T1D) therapy development, we previously generated directly in the NOD strain CRISPR/Cas9-mediated deletions of various combinations of murine MHC genes. These new models improved upon previously available platforms by retaining β2-microglobulin functionality in FcRn and nonclassical MHC class I formation. As proof of concept, we generated H2-Db/H2-Kd double knockout NOD mice expressing human HLA-A*0201 or HLA-B*3906 class I variants that both supported autoreactive diabetogenic CD8+ T cell responses.

Into the Wild: A novel wild-derived inbred strain resource expands the genomic and phenotypic diversity of laboratory mouse models.

The laboratory mouse has served as the premier animal model system for both basic and preclinical investigations for a century. However, laboratory mice capture a narrow subset of the genetic variation found in wild mouse populations. This consideration inherently restricts the scope of potential discovery in laboratory models and narrows the pool of potentially identified phenotype-associated variants and pathways.

Genetically diverse mouse models of SARS-CoV-2 infection reproduce clinical variation in type I interferon and cytokine responses in COVID-19.

Inflammation in response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection drives severity of coronavirus disease 2019 (COVID-19) and is influenced by host genetics. To understand mechanisms of inflammation, animal models that reflect genetic diversity and clinical outcomes observed in humans are needed. We report a mouse panel comprising the genetically diverse Collaborative Cross (CC) founder strains crossed to human ACE2 transgenic mice (K18-hACE2) that confers susceptibility to SARS-CoV-2.

Genetic architecture of heart mitochondrial proteome influencing cardiac hypertrophy.

Mitochondria play an important role in both normal heart function and disease etiology. We report analysis of common genetic variations contributing to mitochondrial and heart functions using an integrative proteomics approach in a panel of inbred mouse strains called the Hybrid Mouse Diversity Panel (HMDP). We performed a whole heart proteome study in the HMDP (72 strains, n=2-3 mice) and retrieved 848 mitochondrial proteins (quantified in ≥50 strains).

Animals, quality and the pursuit of relevance.

In 2021, the National Institutes of Health Advisory Committee to the Director (ACD) announced recommendations to improve the reproducibility of biomedical research using animals. In response, The Jackson Laboratory faculty and institutional leaders identified key strategies to further address this important issue. Taking inspiration from the evolution of clinical trials over recent decades in response to similar challenges, we identified opportunities for improvement, including establishment of common standards, use of genetically diverse populations, requirement for robust study design with appropriate statistical methods, and improvement in public databases to facilitate meta-analyses.