Affiliation:
1. From the Department of Pathology and Laboratory Medicine (C.C., D.M., E.K.-Y.W., Z.L., J.Z., B.Y., M.R., H.L., B.M.M.), The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, St. Paul’s Hospital/Providence Health Care, and the Department of Oral Biological & Medical Sciences (J.C., C.O.), Centre for Blood Research, Life Sciences Centre, University of British Columbia, Vancouver, British Columbia, Canada; and the Division of Pulmonary and Critical Care Medicine (R.M.S.),...
Abstract
Background—
Coxsackievirus B3 (CVB3) causes human myocarditis, which can result in cardiac damage, maladaptive remodeling, and heart failure. Matrix metalloproteinases (MMP)-8 and -9 have been identified in virus-infected myocardium, but their particular roles and underlying mechanisms of effect are unknown. For the first time, we examine the severity of CVB3-induced myocarditis in MMP-8–and MMP-9–deficient mice.
Methods and Results—
CVB3-infected MMP-8 and MMP-9 knockout (KO) mice and corresponding wild-type (WT) mice were euthanized and harvested at 9 days after infection. Expression of MMP-2, -8, -12, and -13 and tissue inhibitors of MMPs was assessed by zymography or immunoblotting on harvested hearts, and in situ hybridization was performed to detect active infection. Infected MMP-9 KO mice had greater myocardial injury and foci of infection than WT mice despite similar pancreatic infection. Increased fibrosis (10.6±2.7% versus 7.1±2.6%,
P
=0.04), viral titer, as well as decreased cardiac output, were evident in MMP-9 KO compared with WT mice as assessed by picrosirius red staining, plaque assay, and echocardiography, respectively. Immune infiltration was also greatly increased in MMP-9 KO compared with WT mice (15.2±12.6% versus 2.0±3.0%,
P
<0.002). Myocardial interferon-β1, interferon-γ, interleukin-6, interleukin-10, and macrophage inflammatory protein-1α expression was elevated in MMP-9 KO mice as measured by quantitative real-time polymerase chain reaction and ELISA. In contrast, MMP-8 KO mice had the same degree of cardiac injury, fibrosis, and viral infection as their WT counterparts.
Conclusions—
During acute CVB3 infection, MMP-9 appears necessary to halt virus propagation in the heart, promote proper immune infiltration and remodeling, and preserve cardiac output.
Publisher
Ovid Technologies (Wolters Kluwer Health)
Subject
Physiology (medical),Cardiology and Cardiovascular Medicine
Cited by
71 articles.
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