cathepsin-g and Atherosclerosis

Topics: Animals; Aorta; Atherosclerosis; Cathepsin G; Collagen; Cytokines; Diet, High-Fat; Leukocyte Elastase; Mice; Mice, Knockout; Mice, Knockout, ApoE; Plaque, Atherosclerotic; Rupture, Spontaneous; Serine Endopeptidases

Subendothelial interaction of LDL with extracellular matrix drives atherogenesis. This interaction can be strengthened by proteolytic modification of LDL. Mast cells (MCs) are present in atherosclerotic lesions, and upon activation, they degranulate and release a variety of neutral proteases. Here we studied the ability of MC proteases to cleave apoB-100 of LDL and affect the binding of LDL to proteoglycans.. Mature human MCs were differentiated from human peripheral blood-derived CD34. Activated human MCs released the neutral proteases tryptase, chymase, carboxypeptidase A3, cathepsin G, and granzyme B. Of these, cathepsin G degraded most efficiently apoB-100, induced LDL fusion, and enhanced binding of LDL to isolated human aortic proteoglycans and human atherosclerotic lesions ex vivo. Double immunofluoresence staining of human atherosclerotic coronary arteries for tryptase and cathepsin G indicated that lesional MCs contain cathepsin G. In the lesions, expression of cathepsin G correlated with the expression of tryptase and chymase, but not with that of neutrophil proteinase 3.. The present study suggests that cathepsin G in human atherosclerotic lesions is largely derived from MCs and that activated MCs may contribute to atherogenesis by enhancing LDL retention.

Topics: Apolipoprotein B-100; Atherosclerosis; Carotid Artery Diseases; Cathepsin G; Cell Degranulation; Cells, Cultured; Coronary Artery Disease; Enzyme Activation; Humans; Lipoproteins, LDL; Mast Cells; Plaque, Atherosclerotic; Protein Binding; Proteoglycans; Proteolysis

Therapeutic targeting of arterial leukocyte recruitment in the context of atherosclerosis has been disappointing in clinical studies. Reasons for such failures include the lack of knowledge of arterial-specific recruitment patterns. Here we establish the importance of the cathepsin G (CatG) in the context of arterial myeloid cell recruitment.. Intravital microscopy of the carotid artery, the jugular vein, and cremasteric arterioles and venules in Apoe. Our observations elucidated a crucial role for CatG during arterial leukocyte adhesion, an effect not found during venular adhesion. Consequently, CatG deficiency attenuates atherosclerosis but not acute lung inflammation. Mechanistically, CatG is immobilized on arterial endothelium where it activates leukocytes to firmly adhere engaging integrin clustering, a process of crucial importance to achieve effective adherence under high-shear flow. Therapeutic neutralization of CatG specifically abrogated arterial leukocyte adhesion without affecting myeloid cell adhesion in the microcirculation. Repetitive application of CatG-neutralizing antibodies permitted inhibition of atherogenesis in mice.. Taken together, these findings present evidence of an arterial-specific recruitment pattern centered on CatG-instructed adhesion strengthening. The inhibition of this process could provide a novel strategy for treatment of arterial inflammation with limited side effects.

Topics: Animals; Arteries; Atherosclerosis; Biomarkers; Cathepsin G; Cell Adhesion; Chemokine CCL5; Chemotaxis; Disease Models, Animal; Endothelium, Vascular; Humans; Integrins; Leukocyte Rolling; Mice; Mice, Knockout; Microcirculation; Myeloid Cells; Protein Binding; Shear Strength; Venules

Cathepsin G is a serine protease with a broad range of catalytic activities, including production of angiotensin II, degradation of extracellular matrix and cell-cell junctions, modulation of chemotactic responses, and induction of apoptosis. Cathepsin G mRNA expression is increased in human coronary atheroma vs. the normal vessel. To assess whether cathepsin G modulates atherosclerosis, cathepsin G knockout (Cstg(-/-)) mice were bred with apolipoprotein E knockout (Apoe(-/-)) mice to obtain Ctsg(+/-)Apoe(-/-) and Ctsg(+/+)Apoe(-/-) mice. Heterozygous cathepsin G deficiency led to a 70% decrease in cathepsin G activity in bone marrow cells, but this reduced activity did not impair generation of angiotensin II in bone marrow-derived macrophages (BMDM). Atherosclerotic lesions were compared in male Cstg(+/-)Apoe(-/-) and Cstg(+/+)Apoe(-/-) mice after 8 wk on a high-fat diet. Plasma cholesterol levels and cholesterol distribution within serum lipoprotein fractions did not differ between genotypes nor did the atherosclerotic lesion areas in either the aortic root or aortic arch. Cstg(+/-)Apoe(-/-) mice, however, showed a lower percentage of complex lesions within the aortic root and a smaller number of apoptotic cells compared with Cstg(+/+)Apoe(-/-) littermates. Furthermore, apoptotic Cstg(-/-) BMDM were more efficiently engulfed by phagocytic BMDM than were apoptotic Ctsg(+/+) BMDM. Thus cathepsin G activity may impair efferocytosis, which could lead to an accumulation of lesion-associated apoptotic cells and the accelerated progression of early atherosclerotic lesions to more complex lesions in Apoe(-/-) mice.

Topics: Angiotensin II; Animals; Aorta; Apolipoproteins E; Apoptosis; Atherosclerosis; Cathepsin G; Diet, High-Fat; Macrophages; Male; Mice; Mice, Knockout; Phagocytosis; Plaque, Atherosclerotic

Remodeling of extracellular matrix (ECM) plays an important role in both atherosclerosis and aneurysm disease. Serine protease inhibitor A3 (serpinA3) is an inhibitor of several proteases such as elastase, cathepsin G and chymase derived from mast cells and neutrophils. In this study, we investigated the putative role of serpinA3 in atherosclerosis and aneurysm formation. SerpinA3 was expressed in endothelial cells and medial smooth muscle cells in human atherosclerotic lesions and a 14-fold increased expression of serpinA3n mRNA was found in lesions from Apoe-/- mice compared to lesion-free vessels. In contrast, decreased mRNA expression (-80%) of serpinA3 was found in biopsies of human abdominal aortic aneurysm (AAA) compared to non-dilated aortas. Overexpression of serpinA3n in transgenic mice did not influence the development of atherosclerosis or CaCl2-induced aneurysm formation. In situ zymography analysis showed that the transgenic mice had lower cathepsin G and elastase activity, and more elastin in the aortas compared to wild-type mice, which could indicate a more stable aortic phenotype. Differential vascular expression of serpinA3 is clearly associated with human atherosclerosis and AAA but serpinA3 had no major effect on experimentally induced atherosclerosis or AAA development in mouse. However, serpinA3 may be involved in a phenotypic stabilization of the aorta.

Topics: alpha 1-Antichymotrypsin; Aneurysm; Animals; Atherosclerosis; Calcium Chloride; Cathepsin G; Cell Line; Cytokines; Endothelial Cells; Enzyme Activation; Gene Expression; Gene Expression Regulation; Humans; Inflammation Mediators; Mast Cells; Mice; Mice, Inbred C57BL; Mice, Transgenic; Pancreatic Elastase; RNA, Messenger; Serine Proteinase Inhibitors