Membrane-Type Serine Protease-1/Matriptase Induces Interleukin-6 and -8 in Endothelial Cells by Activation of Protease-Activated Receptor-2

Abstract

Objective-The serine protease MT-SP1/matriptase plays an important role in cell migration and matrix degradation.Hepatocyte growth factor (HGF), urokinase-type plasminogen activator (uPA), and protease-activated receptor 2 (PAR-2) have been identified as in vitro substrates of MT-SP1/matriptase. Because PAR-2 is expressed in endothelial cells and contributes to inflammatory processes, we sought to investigate the effects of MT-SP1/matriptase on endothelial cytokine expression and analyzed MT-SP1/matriptase expression in vascular cells and atherosclerotic lesions. Methods and Results-In endothelial cells, recombinant MT-SP1/matriptase dose-dependently induced interleukin (IL)-8and IL-6 mRNA and protein expression dependent on its proteolytic activity. MT-SP1/matriptase time-dependently induced phosphorylation of p38 MAPK and p42/44 MAPK. Inhibitor experiments revealed that p38 MAPK and PKC␣ were necessary for IL-8 induction. PAR-2 downregulation abolished and PAR-2 overexpression augmented MT-SP1/ matriptase-induced IL-8 expression as evidence for PAR-2 signaling. In human atherectomies, MT-SP1/matriptase was expressed in blood cells adherent to the endothelium. Concordantly, basal MT-SP1/matriptase expression was detected in isolated monocytes. Coincubation of monocytes and endothelial cells resulted in an increased IL-8 release, which was reduced after downregulation of endothelial PAR-2 and monocytic MT-SP1/matriptase. Key Words: pathophysiology Ⅲ growth factors Ⅲ endothelium M T-SP1/matriptase is a trypsin-like, multi-domain serine protease expressed primarily in epithelial cells. [1][2][3][4] Its importance in the biology of surface-lining epithelial cells became apparent in MT-SP1/matriptase knockout mice presenting with a severe deficient epidermal barrier function as well as abnormal hair follicle development and disturbed thymic homeostasis. 5 Moreover, MT-SP1/matriptase is upregulated in different malignant tissues 6 -8 and may be expressed in microvascular endothelial cells. 9 Besides its N-terminal transmembrane signal anchor MT-SP1/matriptase contains two putative regulatory modules: 2 tandem repeats of a CUB domain (C1r/s, Uegf, Bone morphogenetic protein-1) and 4 tandem repeats of a low density lipoprotein (LDL) receptor domain. 1,4 The C-terminal serine protease domain consists of a catalytic triad comprising His-57, In addition to the membrane-anchored form of MT-SP1/matriptase, a soluble form of the protease has been identified lacking the N-terminal 172 amino acids. 1 Shedding from the extracellular surface 11,12 or alternative splicing 3,10 may be the mechanisms leading to the truncated form of MT-SP1/matriptase isolated from human milk. 13 Cleavage within its activation motif generates the 2-chain active protease from a single-chain zymogen. The activation of MT-SP1/matriptase requires its cognate Kunitz-type inhibitor hepatocyte growth factor activator inhibitor (HAI)-1, its noncatalytic domains as well as its serine protease domain. 14 Three macromolecular substrates of MT-SP1/matriptase h...

Membrane-anchored Serine Protease Matriptase Is a Trigger of Pulmonary Fibrogenesis

“…Obviously, TGF-b is not the sole cytokine contributing to fibrogenesis, and multiple factors and pathways involved in IPF pathogenesis (47) may also impact matriptase expression. Although matriptase expression and functions were initially ascribed to epithelial cells, recent studies demonstrated that matriptase is expressed in diverse cell types, including normal and malignant mesenchymal cells (48)(49)(50)(51)(52). Together with the present study, this shows the remarkable plasticity of matriptase in response to different stimuli, raising important new questions.…”

Inflammatory Interaction Between LIGHT and Proteinase-Activated Receptor-2 in Endothelial Cells

“…29 Moreover, Seitz et al have recently shown that PAR-2 activation increases IL-6 and IL-8 expression in endothelial cells. 10 However, although we found that SLIGKV had a slight effect on IL-8 and MCP-1 release in Increased PAR-2 expression in monocytes from unstable angina patients. The figure shows mRNA levels of PAR-2 in freshly isolated monocytes from patients with stable (nϭ14) and unstable (nϭ14) angina pectoris (AP) and sex-and age-matched healthy controls (nϭ10), as assessed by real-time RT-PCR and normalized to ␤-actin expression.…”

“…5 PAR-2 has also been reported to exert inflammatory effects in these cells, including the induction of IL-6 and IL-8. 10 To examine the biological relevance of the LIGHT-mediated upregulation of PAR-2, we examined the effect of rhLIGHT (100 ng/mL), the PAR-2-activating peptide SLIGKV (10 mol/L and 100 mol/L), or a combination thereof on the release of IL-8 and MCP-1 in HUVECs after 8 and 20 hours of stimulation. As shown in Figure 2A and 2B, although SLIGKV show no or only modest effects on MCP-1 on its own, it markedly enhanced the LIGHT-stimulated release of this chemokine at both time points in a dosedependent manner (Ϸ2-fold increase when these stimuli were combined, 100 mol/L SLIGKV).…”

“…9 PAR-2 has putative inflammatory roles and was recently proposed to be involved in atherogenesis by contributing to vascular inflammation. 10 In the present study, we further examined the possible pathogenic role of the LIGHT-mediated PAR-2 response in endothelial cells by several approaches, including experimental as well as clinical studies.…”

Epithin/PRSS14 proteolytically regulates angiopoietin receptor Tie2 during transendothelial migration

“…48 In addition, several reports show that epithin is expressed in the hematopoietic lineage cells of monocytes, macrophages, and mast cells. [49][50][51] These results raise the intriguing possibility that epithin may also be involved in the regulation of the exit of hematopoietic stem cells from their niche by proteolytic cleavage. Indeed, we found that transendothelial cell migration of activated macrophages were dependent on epithin (data not shown).…”