Tissue inhibitor of metalloproteinases 3-dependent microvascular endothelial cell barrier function is disrupted under septic conditions

Abstract

Sepsis is associated with dysfunction of microvascular endothelial cells (MVEC) leading to tissue edema and multiple organ dysfunction. Metalloproteinases can regulate MVEC function through processing of cell surface proteins, and tissue inhibitor of metalloproteinases 3 (TIMP3) regulates metalloproteinase activity in the lung following injury. We hypothesize that TIMP3 promotes normal pulmonary MVEC barrier function through inhibition of metalloproteinase activity. Naive Timp3(-/-) mice had significantly higher basal pulmonary microvascular Evans blue (EB) dye-labeled albumin leak vs. wild-type (WT) mice. Additionally, cecal-ligation/perforation (CLP)-induced sepsis significantly increased pulmonary microvascular EB-labeled albumin leak in WT but not Timp3(-/-) mice. Similarly, PBS-treated isolated MVEC monolayers from Timp3(-/-) mice displayed permeability barrier dysfunction vs. WT MVEC, evidenced by lower transendothelial electrical resistance and greater trans-MVEC flux of fluorescein-dextran and EB-albumin. Cytomix (equimolar interferon γ, tumor necrosis factor α, and interleukin 1β) treatment of WT MVEC induced significant barrier dysfunction (by all three methods), and was associated with a time-dependent decrease in TIMP3 mRNA and protein levels. Additionally, basal Timp3(-/-) MVEC barrier dysfunction was associated with disrupted MVEC surface VE-cadherin localization, and both barrier dysfunction and VE-cadherin localization were rescued by treatment with GM6001, a synthetic metalloproteinase inhibitor. TIMP3 promotes normal MVEC barrier function, at least partially, through inhibition of metalloproteinase-dependent disruption of adherens junctions, and septic downregulation of TIMP3 may contribute to septic MVEC barrier dysfunction.

Overexpression of TIMP3 Protects Against Cardiac Ischemia/Reperfusion Injury by Inhibiting Myocardial Apoptosis Through ROS/Mapks Pathway

“…It has previously been shown that TIMP3 expression is reduced in atherosclerosis, abdominal aortic aneurysm and type 2 diabetes mellitus from human subjects or experimental models [10, 26, 27]. The abnormal TIMP3 expression served as a causal mediator of the corresponding pathophysiologic process [10, 11, 13, 15]. Notably, TIMP3 is highly expressed in heart, and its expression is also decreased in myocardial infarction animal model and heart failure patients [28, 29].…”

“…The tissue inhibitor of metalloproteinases (TIMPs) plays a critical role in regulating MMPs activity and ECM formation, because the imbalance between MMPs and TIMPs markedly disrupts ECM integrity in multiple cardiovascular diseases [9, 10]. Among the four TIMPs, TIMP3 is a unique member, which not only inhibits MMPs activity, but also functions as a potent inhibitor of ADAMs [11, 12], indicating a crucial role of TIMP3 in the regulation of ECM deposition.…”

“…ApoE -/- TIMP3 -/- mice showed accelerated atherosclerosis and aneurysms, while upregualtion of TIMP3 could limit the development of atherosclerosis [10, 13, 14]. Loss of TIMP3 exacerbated sepsis- or hypertension-induced endothelial cell barrier dysfunction [11, 15]. Correspondingly, there are also some limited studies indicating TIMP3 has a role in regulation of heart function.…”

Endothelial Response to Glucocorticoids in Inflammatory Diseases

“…MMPs modulate endothelial barrier integrity through processing of adherens and tight junction proteins (167). MMP-8 inhibition protects mice from death in sepsis (168–170).…”

“…Arpino and colleagues showed that inhibition of metalloproteinase-mediated adherens junctions’ disruption by tissue inhibitor of metalloproteinases-3 (TIMP-3) preserves normal endothelial barrier integrity. Pulmonary microvascular endothelial cells monolayers from TIMP-3 KO mice spontaneously displayed barrier dysfunction associated with disrupted surface VE-cadherin localization (167). …”