Biology subjects

Lavine, K. J.

Publications and source records attributed to Lavine, K. J..

22 records · Page 2Linked to original sources

bioRxiv2021

Resident Cardiac Macrophages Mediate Adaptive Myocardial Remodeling

Cardiac macrophages represent a heterogeneous cell population with distinct origins, dynamics, and functions. Recent studies have revealed that C-C Chemokine Receptor 2 positive (CCR2+) macrophages derived from infiltrating monocytes regulate myocardial inflammation and heart failure pathogenesis. Comparatively little is known about the functions of tissue resident (CCR2-) macrophages. Herein, we identify an essential role for CCR2- macrophages in the chronically failing heart. Depletion of CCR2- macrophages in mice with dilated cardiomyopathy accelerated mortality and impaired ventricular remodeling and coronary angiogenesis, adaptive changes necessary to maintain cardiac output in the setting of reduced cardiac contractility. Mechanistically, CCR2- macrophages interacted with neighboring cardiomyocytes via focal adhesion complexes and were activated in response to mechanical stretch through a transient receptor potential vanilloid 4 (TRPV4) dependent pathway that controlled growth factor expression. These findings establish a role for tissue resident macrophages in adaptive cardiac remodeling and introduce a new mechanism of cardiac macrophage activation.

immunology↗

bioRxiv2020

SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis

Epidemiological studies of the COVID-19 pandemic have revealed evidence of cardiac involvement and documented that myocardial injury and myocarditis are predictors of poor outcomes. Nonetheless, little is understood regarding SARS-CoV-2 tropism within the heart and whether cardiac complications result directly from myocardial infection. Here, we develop a human engineered heart tissue model and demonstrate that SARS-CoV-2 selectively infects cardiomyocytes. Viral infection is dependent on expression of angiotensin-I converting enzyme 2 (ACE2) and endosomal cysteine proteases, suggesting an endosomal mechanism of cell entry. After infection with SARS-CoV-2, engineered tissues display typical features of myocarditis, including cardiomyocyte cell death, impaired cardiac contractility, and innate immune cell activation. Consistent with these findings, autopsy tissue obtained from individuals with COVID-19 myocarditis demonstrated cardiomyocyte infection, cell death, and macrophage-predominate immune cell infiltrate. These findings establish human cardiomyocyte tropism for SARS-CoV-2 and provide an experimental platform for interrogating and mitigating cardiac complications of COVID-19.

immunology↗

bioRxiv2020

SVEP1, a novel human coronary artery disease locus, promotes atherosclerosis

A low-frequency variant of SVEP1, an extracellular matrix protein, is associated with risk of coronary disease in humans independent of plasma lipids. Despite a robust statistical association, however, it was unclear if and how SVEP1 might contribute to atherosclerosis. Here, using Mendelian randomization and complementary mouse models, we provide evidence that SVEP1 promotes atherosclerosis in humans and mice. We find that SVEP1 is expressed by vascular smooth muscle cells (VSMCs) within the atherosclerotic plaque. VSMCs also interact with SVEP1, causing proliferation and dysregulation of key differentiation pathways, including integrin and Notch signaling. Fibroblast growth factor receptor transcription increases in VSMCs interacting with SVEP1, and is further increased by the coronary disease-associated SVEP1 variant. These effects ultimately drive inflammation and promote atherosclerosis. Taken together, our results suggest that VSMC-derived SVEP1 is a pro-atherogenic factor, and support the concept that pharmacological inhibition of SVEP1 should protect against atherosclerosis in humans.

genetics↗

bioRxiv2020

Chemokine receptor 2-targeted molecular imaging in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, inflammatory lung disease that is monitored clinically by measures of lung function, without effective molecular markers of disease activity or therapeutic efficacy. Lung immune cells active in the pro-fibrotic process include inflammatory monocyte and interstitial macrophages that express the C-C motif chemokine receptor 2 (CCR2). CCR2+ monocyte lung influx is essential for disease phenotypes in models of fibrosis and identified in lungs from subjects with IPF. Here, we show that our peptide-based radiotracer 64Cu-DOTA-ECL1i identifies CCR2+ inflammatory monocytes and interstitial macrophages in multiple preclinical mouse models of lung fibrosis, using positron emission tomography (PET) imaging. Mice with bleomycin-induced fibrosis treated with blocking antibodies to interleukin-1{beta}, a mediator of fibrosis associated with CCR2+ cell inflammation, or with pirfenidone, an approved anti-fibrotic agent, demonstrated decreased CCR2-dependent interstitial macrophage accumulation and reduced 64Cu-DOTA-ECL1i PET uptake, compared to controls. Lung tissues from patients with fibrotic lung disease demonstrated abundant CCR2+ cells surrounding regions of fibrosis, and an ex vivo tissue-binding assay showed correlation between radiotracer localization and CCR2+ cells. In a phase 0/1 clinical study of 64Cu-DOTA-ECL1i PET, healthy volunteers showed little lung uptake, while subjects with pulmonary fibrosis exhibited increased uptake, notably in zones of subpleural fibrosis, reflecting the distribution of CCR2+ cells in the profibrotic niche. These findings support a pathologic role of inflammatory lung monocytes/macrophages in fibrotic lung disease and the translational use of 64Cu-DOTA-ECL1i PET to track CCR2-specific inflammation for image-guided therapy. One Sentence SummaryPET imaging of CCR2+ cells in lung fibrosis identifies a therapeutic response in mouse models and displays a perifibrotic signal in subjects with IPF.

cell biology↗