Biology subjects

Owen, M. C.

Publications and source records attributed to Owen, M. C..

4 recordsLinked to original sources

bioRxiv2026

CD14 Blockade Attenuates Arrhythmogenic Cardiomyopathy

Background: Arrhythmogenic cardiomyopathy (ACM) is a genetic and phenotypically heterogeneous myocardial disorder characterized by progressive cardiomyocyte loss, immune cell infiltration, and fibro-fatty replacement of the ventricular myocardium, with an increased risk of sudden cardiac death (SCD), predominantly caused by mutations in cardiac desmosomal genes including PKP2, DSP, and DSG2. We previously described the pivotal role of NF{kappa}B and CCR2+ cardiac macrophage-triggered inflammation in ACM pathogenesis. Methods: WT or Dsg2mut/mut mice were treated with either isotype control or anti-CD14 antibody once a week for the described treatment period (4 or 8 weeks). At the end of the treatment period, disease characteristics were assessed by echocardiography, electrocardiography, histology, immunofluorescence, positron emission tomography (PET) imaging and single-cell transcriptomics. Results: Here, we demonstrate the efficacy of neutralizing CD14 signaling, an important mediator of inflammatory macrophage activation, in attenuating ACM disease in vivo. Additionally, we elucidate shifts in the cellular and transcriptomic landscapes that occur following anti-CD14 antibody treatment in a well-established mouse model of ACM and identify substantial reductions in inflammatory macrophage and pro-fibrotic fibroblast populations. Conclusion: This study provides evidence that blockade of CD14 can attenuate the ACM disease phenotype. It may do so by inhibiting macrophage-based activation and inflammation, while also altering the transcriptional state of other important cell types. Collectively, these findings suggest that CD14 inhibition may be an effective option for ACM, which should be explored in early-phase clinical studies.

immunology↗

bioRxiv2026

Collateral Immune Cell Signaling Compromises the Efficacy of T-cell Engaging Therapies for Cardiac Fibrosis

Cardiac fibrosis is causally linked to heart failure progression and survival. Currently, there are no approved treatments that directly target cardiac fibrosis. Recent studies have identified a subset of activated cardiac fibroblasts distinct from myofibroblasts that are marked by fibroblast activation protein (FAP) expression, emerge in the injured and diseased heart through inflammatory signaling, and contribute to fibrosis. Using a genetic mouse model, we demonstrate the potential benefits of FAP+ fibroblast depletion following myocardial infarction. Unexpectedly, while FAP targeted bispecific T-cell engaging antibodies (BiTE(R) molecules) effectively eliminate FAP+ fibroblasts from the heart, they surprisingly lead to accelerated deterioration of cardiac function, enhanced remodeling, and increased scar size. FAP BiTE(R) molecules elicit a robust cytokine response within the heart with prominent activation of interferon gamma (IFNg) and CD40 ligand pathways. Target cell killing was independent of IFNg; and CD40L signaling and blockade of these pathways was sufficient to unmask the protective therapeutic effects of FAP+ fibroblast depletion. Mechanistically, we reveal that IFNg; signaling to fibroblasts drives the differentiation of an independent lineage of activated fibroblasts not typically found in the infarcted heart, which are responsible for the harmful effects of FAP BiTE(R) molecules. Collectively, these findings highlight a previously unrecognized cardiac liability of BiTE(R) molecules and inform the design of the next generation of therapeutics.

immunology↗

bioRxiv2024

Novel murine model of human astrovirus infection reveals a cardiovascular tropism

Astroviruses are a common cause of gastrointestinal disease in humans and have been recognized to cause fatal cases of encephalitis. A major barrier to the study of human-infecting astroviruses is the lack of an in vivo model, as previous attempts failed to identify a suitable host that supports viral replication. We describe a novel murine model of infection using astrovirus VA1/HMO-C (VA1), an astrovirus with high seroprevalence in humans that is a causative agent of encephalitis. VA1 RNA levels peak in heart tissue at day 7 post-inoculation. The cardiotropism was observed in multiple different murine genetic backgrounds evidenced by high VA1 RNA loads in heart tissue of A/J, C57BL/6, C3H/HeJ, Balb/c, and J:ARC mice. Infectious VA1 particles could be recovered from heart tissue 3 and 5 days post-inoculation. Intracellular viral capsid was present in tissue sections based on immunofluorescent staining and viral RNA was detected in cardiac myocytes, endocardium, and endothelial cells based on fluorescent in situ hybridization and confocal microscopy. Histologically, we identified inflammatory infiltrates consistent with myocarditis in some mice, with viral RNA co-localizing with the infiltrates. These foci contained CD3+ T cells and CD68+ macrophages. Viral RNA levels increased by > 10-fold in heart tissue or serum samples from Rag1 or Stat1 knockout mice, demonstrating the role of both adaptive and innate immunity in the response to VA1 infection. Based on the in vivo tropisms, we also tested cardiac-derived primary cells and determined that VA1 can replicate in human cardiac microvascular and coronary artery endothelial cells, suggesting a novel cardiovascular tropism in human cells. This novel in vivo model of a human-infecting astrovirus enables further characterization of viral pathogenesis and reveals a new cardiovascular tropism of astroviruses. Author SummaryAstroviruses typically cause viral diarrhea in humans but can also cause serious infections of the brain. Previously, the methods available to study how these viruses lead to invasive infections were limited. Here, we describe the first system to study human-infecting astroviruses using mice. We demonstrate that mice are susceptible to astrovirus VA1, a strain that commonly infects humans and has been linked to fatal brain infections. The virus infected heart tissue and was associated with inflammation. When mice with impaired immune systems were infected with VA1, they were found to have higher amounts of virus in their hearts and blood. Linking back to human health, we also found that VA1 can infect cells derived from human blood vessels of the heart. This model will enable us to better understand how astroviruses cause disease and how the immune system responds to infection. Our findings also suggest that astroviruses could be linked to cardiovascular diseases, including in humans. In the future, we can develop interventions that will prevent and treat astrovirus infections in humans.

microbiology↗

bioRxiv2022

The highly conserved stem-loop II motif is important for the lifecycle of astroviruses but dispensable for SARS-CoV-2

The stem-loop II motif (s2m) is an RNA element present in viruses from divergent viral families, including astroviruses and coronaviruses, but its functional significance is unknown. We created deletions or substitutions of the s2m in astrovirus VA1 (VA1), classic human astrovirus 1 (HAstV1) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For VA1, recombinant virus could not be rescued upon partial deletion of the s2m or substitutions of G-C base pairs. Compensatory substitutions that restored the G-C base-pair enabled recovery of VA1. For HAstV1, a partial deletion of the s2m resulted in decreased viral titers compared to wild-type virus, and reduced activity in a replicon system. In contrast, deletion or mutation of the SARS-CoV-2 s2m had no effect on the ability to rescue the virus, growth in vitro, or growth in Syrian hamsters. Our study demonstrates the importance of the s2m is virus-dependent.

microbiology↗