ABSTRACT
OBJECTIVE: We investigated the potential role of ADAMTS-1 (a disintegrin and metalloprotease with thrombospondin motif type I) in atherogenesis. METHODS AND RESULTS: ADAMTS-1 is expressed at the highest levels in the aorta when compared with other human tissues examined. Immunolocalization studies in human aorta and coronary artery indicate that ADAMTS-1 expression is mainly seen at low levels in the medial layer, but upregulated in the intima when plaque is present. We found that ADAMTS-1 mRNA levels are significantly higher in proliferating/migrating cultured primary aortic vascular smooth muscle cells (VSMCs) compared with resting/confluent cells. Using the mouse carotid artery flow cessation model, we show that there are differences in vessel remodeling in ADAMTS-1 transgenic/apoE-deficient mice compared with apoE deficiency alone, particularly a significant increase in intimal hyperplasia. We show that ADAMTS-1 can cleave the large versican containing proteoglycan population purified from cultured human aortic VSMCs. Finally, using versican peptide substrates, we show data suggesting that ADAMTS-1 cleaves versican at multiple sites. CONCLUSIONS: We hypothesize that ADAMTS-1 may promote atherogenesis by cleaving extracellular matrix proteins such as versican and promoting VSMC migration.
Subject(s)
Arteriosclerosis/pathology , Carotid Artery, Common/pathology , Chondroitin Sulfate Proteoglycans/metabolism , Disintegrins/physiology , Immunohistochemistry/methods , Metalloendopeptidases/physiology , Peptide Hydrolases/metabolism , ADAM Proteins , ADAMTS1 Protein , Adolescent , Animals , Arteriosclerosis/metabolism , Carotid Artery, Common/chemistry , Carotid Artery, Common/metabolism , Carotid Artery, Common/surgery , Cell Line , Disease Models, Animal , Disintegrins/biosynthesis , Disintegrins/immunology , Disintegrins/metabolism , Humans , Hydrolysis , Lectins, C-Type , Ligation/methods , Male , Metalloendopeptidases/biosynthesis , Metalloendopeptidases/immunology , Metalloendopeptidases/metabolism , Mice , Mice, Inbred C57BL , Middle Aged , Muscle, Smooth, Vascular/chemistry , Muscle, Smooth, Vascular/metabolism , Muscle, Smooth, Vascular/pathology , Myocytes, Smooth Muscle/chemistry , Myocytes, Smooth Muscle/metabolism , Myocytes, Smooth Muscle/pathology , Neovascularization, Pathologic/pathology , Reverse Transcriptase Polymerase Chain Reaction/methods , VersicansABSTRACT
OBJECTIVE: The inhibitory effect of alpha-haemolytic Streptococci (AHS) in vitro on the three commonest otitis media pathogens, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, was previously investigated. The aim of this study was to determine the mechanism of this inhibitory activity. MATERIAL AND METHODS/RESULTS: When fractions of AHS filtrate were assayed to determine their inhibitory activity after size-exclusion chromatography, the inhibitory activity was found in the fractions with a low molecular weight. The inhibitory effect was completely reversed when catalase was added to the cell-free filtrate of AHS. A quantitative method also revealed high production (approximately 3 mmol/l) of hydrogen peroxide in the AHS filtrate with the best inhibitory activity. Electron microscopy of bacteria exposed to AHS filtrate with an inhibitory effect showed changes similar to bacteria exposed to hydrogen peroxide. CONCLUSIONS: We conclude that the inhibitory effect of AHS is most likely due to the production of hydrogen peroxide. The significance of hydrogen peroxide production of AHS is discussed in relation to the non-specific and specific mucosal defence systems.
Subject(s)
Hydrogen Peroxide/metabolism , Nasopharynx/microbiology , Otitis Media/microbiology , Viridans Streptococci/metabolism , Bacterial Physiological Phenomena , Haemophilus influenzae/growth & development , Humans , Moraxella catarrhalis/growth & development , Streptococcus pneumoniae/growth & development , Viridans Streptococci/growth & development , Viridans Streptococci/isolation & purificationABSTRACT
Antioxidant protein 2 (AOP2) is a member of a family of thiol-specific antioxidants, recently renamed peroxiredoxins, that evolved as part of an elaborate system to counteract and control detrimental effects of oxygen radicals. AOP2 is found in endothelial cells, erythrocytes, monocytes, T and B cells, but not in granulocytes. AOP2 was found solely in the cytoplasm and was not associated with the nuclear or membrane fractions; neither was it detectable in plasma. Further experiments focused on the function of AOP2 in erythrocytes where it is closely associated with the hemoglobin complex, particularly with the heme. An investigation of the mechanism of this interaction demonstrated that the conserved cysteine-47 in AOP2 seems to play a role in AOP2-heme interactions. Recombinant AOP2 prevented induced as well as noninduced methemoglobin formation in erythrocyte hemolysates, indicating its antioxidant properties. We conclude that AOP2 is part of a sophisticated system developed to protect and support erythrocytes in their many physiological functions.
Subject(s)
Erythrocytes/metabolism , Methemoglobin/metabolism , Peroxidases , Proteins/metabolism , Animals , Blotting, Western , Cysteine/metabolism , Endothelium, Vascular/metabolism , Heme/metabolism , Hemoglobins/metabolism , Methemoglobin/biosynthesis , Peroxiredoxin VI , Peroxiredoxins , Protein Binding/physiology , Protein Biosynthesis , Proteins/immunology , SwineABSTRACT
Identification of tissue-specific mechanisms involved in the pathophysiology of inflammatory skin diseases could offer new possibilities to develop effective therapies with fewer systemic effects. The serine protease stratum corneum chymotryptic enzyme is preferentially expressed in cornifying epithelia. We have previously reported on increased expression of the stratum corneum chymotryptic enzyme in psoriasis. Here is reported an increased epidermal expression of stratum corneum chymotryptic enzyme also found in chronic lesions of atopic dermatitis. Transgenic mice expressing human stratum corneum chymotryptic enzyme in suprabasal epidermal keratinocytes were found to develop pathologic skin changes with increased epidermal thickness, hyperkeratosis, dermal inflammation, and severe pruritus. The results suggest that stratum corneum chymotryptic enzyme may be involved in the pathogenesis of inflammatory skin diseases, and that stratum corneum chymotryptic enzyme and related enzymes should be evaluated as potential targets for new therapies.
