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Objective. We aimed to characterize the expression of indoleamine 2,3-dioxygenase (IDO) or IDO-induced tryptophan degradation-dependent pathways, which may lead to suppression of T cells and possible protection against atherosclerosis. Methods and results. Expression of IDO and IDO-related pathway components was analyzed in advanced human atherosclerotic plaques ( n = 24) and in non-atherosclerotic arteries ( n = 6). Up-regulation of IDO and genes related to the IDO pathway was found to be pronounced in atherosclerotic plaques. Immunohistochemistry demonstrated IDO protein in the atheromatous core and co-distribution with monocyte-macrophages (CD68-positive cells). In gene-set enrichment analysis, the IDO pathway revealed a significant (false discovery rate (FDR) = 0.07) regulatory T cell, fork-head box protein 3 (FoxP3)-initiated CD28-cytotoxic T lymphocyte-associated antigen 4 (CTLA-4)-inducible T cell co-stimulator (ICOS)-driven pathway leading to activation of IDO expression in antigen-presenting cells (APCs). Expression of these IDO pathway genes varied between 2.1- and 16.8-fold as compared to control tissues ( P < 0.05 for all). Conclusions. IDO and the IDO-related pathway are important mediators of the immunoinflammatory responses in advanced atherosclerosis offering new viable therapeutic targets for the development of antiatherogenic immunosuppressive therapies. [ABSTRACT FROM AUTHOR]

Objective. Previously, we scanned all 23,000 human genes for differential expression between normal and atherosclerotic tissues and found the involvement of ADAM8. Methods. We investigated the expression of ADAM8 mRNA and protein level in human atherosclerotic tissues and non-atherosclerotic internal thoracic arteries as well as the association of ADAM8 2662 T/G single nucleotide polymorphism (SNP) with the extent of coronary atherosclerosis and with the risk of fatal myocardial infarction. Results. ADAM8 mRNA was up-regulated in carotid, aortic, and femoral atherosclerotic plaques (n=24) when compared with non-atherosclerotic arteries. ADAM8 protein expression was increased in advanced atherosclerotic plaques as compared to control vessels wherein it was localized to macrophages and smooth muscle cells The G allele carriers of the ADAM8 2662 T/G SNP had significantly larger areas of fibrotic, calcified, and complicated plaques in coronary arteries (P=0.027, P=0.011, and P=0.011, respectively) and significantly higher occurrence of myocardial infarction (MI) (P=0.004) and fatal pre-hospital MI (P=0.003) than did the TT homozygotes. Conclusion. ADAM8 is a promising candidate to be involved in atherosclerosis, and its 2662 T/G allelic variant significantly associates with advanced atherosclerotic lesion areas and MI. [ABSTRACT FROM AUTHOR]

Background and aims. The expression of disintegrin and metalloprotease ADAM-9, ADAM-15, and ADAM-17 has been associated with cell-cell, cell-platelet, and cell-matrix interactions and inflammation. They are possibly implicated in the pathophysiology of atherosclerosis. Methods and results. Whole-genome expression array and quantitative real-time polymerase chain reaction (PCR) analysis confirmed that ADAM-9, ADAM-15, and ADAM-17 are upregulated in advanced human atherosclerotic lesions in samples from carotid, aortic, and femoral territories compared to samples from internal thoracic artery (ITA) free of atherosclerotic plaques. Western analysis indicated that the majority of these ADAMs were in the catalytically active form. ADAM-9, ADAM-15, and ADAM-17-expressing cells were shown to co-localize with CD68-positive cells of monocytic origin in the atherosclerotic plaques using immunohistochemistry and double-staining immunofluorescence analysis. Co-localization was demonstrated in all vascular territories. In the carotid territory, cells expressing the ADAMs co-distributed also with smooth muscle cells and, in femoral territory, with CD31-positive endothelial cells, indicating that the ADAM expression pattern depends on vascular bed territory. Conclusions. Present findings provide strong evidence for the involvement of catalytically active ADAM-9, ADAM-15, and ADAM-17 in advanced atherosclerosis, most notably associated with cells of monocytic origin. [ABSTRACT FROM AUTHOR]

Abstract: Background: Proprotein convertase subtilisin/kexin (PCSK) enzymes cleave proproteins into mature end products. Previously, MBTPS1 and PCSK9 have been shown to regulate cholesterol metabolism and LDL receptor recycling, whereas FURIN and PCSK5 have been suggested to inactivate lipases and regulate inflammation in atherosclerosis. Here, we systematically analyzed the expression of PCSKs and their targets in advanced atherosclerotic plaques. Methods and results: Microarray and quantitative real-time PCR experiments showed that FURIN (42.86 median fold, p =2.1e−8), but no other PCSK, is universally overexpressed in the plaques of different vascular regions. The mRNA expression screen of PCSK target proteins in plaques identified many known factors, but it also identified the significant upregulation of the previously overlooked furin-processed B cell activating cytokines APRIL (TNFSF13, 2.52 median fold, p =3.0e−5) and BAFF (TNFSF13B, 2.97 median fold, p =7.6e−6). The dysregulation of FURIN did not associate with its htSNPs or the previously reported regulatory SNP (−229, rs4932178) in the promoter. Immunohistochemistry experiments showed the upregulation of FURIN in the plaque lymphocytes and macrophages where it was co-expressed with BAFF/TNFSF13B and APRIL/TNFSF13. Conclusions: Our data unequivocally show that FURIN is the primary PCSK that is dysregulated in the immune cells of advanced human atherosclerotic plaques, which implies a role for this enzyme in plaque pathology. Therefore, drugs that inhibit FURIN in arteries may modulate the course of this disease. [Copyright &y& Elsevier]

Abstract: Objective: Ischemic preconditioning reduces infarct size and improves hemodynamic function. Unstable angina may be a clinical analogue to ischemic preconditioning, and involve activation of gene programs. We hypothesized that preceding unstable angina and/or ischemic preconditioning activated genes regulated by nuclear factor kappa B (NFκB) or hypoxia-inducible factor 1 alpha in parallel to improved cardiac function. Methods: Patients undergoing coronary artery bypass grafting with stable or unstable angina were subjected to ischemic preconditioning or sham treatment (n =10–11 in each group). Central hemodynamics were monitored. Left ventricular and atrial biopsies were harvested before cardioplegic arrest and after 25min of reperfusion. Expression of heat shock protein 72 was evaluated by immunoblot, and activation of NFκB was detected by electrophoretic mobility shift assay. Real-time PCR was used to quantify expression of genes regulated by NFκB (inducible nitric oxide synthase, tumor necrosis factor-alpha, intercellular adhesion molecule 1) or by hypoxia-inducible factor 1 alpha (heme oxygenase-1, glucose transporter-1 and vascular endothelial growth factor-A). Results: Ischemic preconditioning improved postoperative cardiac index and left ventricular stroke work index in both stable and unstable groups on the first postoperative day. Expression of hypoxia-inducible factor 1 alpha regulated genes was not influenced by cardioplegia and reperfusion, ischemic preconditioning or unstable angina. Expression of the NFκB-regulated genes increased after cardioplegia and reperfusion, but this was not influenced by ischemic preconditioning in stable patients. Inducible nitric oxide synthase and tumor necrosis factor expression were reduced after ischemic preconditioning in patients with unstable angina. There were no significant differences in gene expression between stable and unstable patients before cardioplegia and ischemic preconditioning. NFκB translocation at reperfusion was reduced in stable preconditioned and unstable control patients compared to stable controls. Heat shock protein 72 expression increased after preconditioning of unstable patients. Conclusion: Cardiac function was improved by ischemic preconditioning in both stable and unstable patients. Unstable angina per se had no effect. NFκB-regulated genes were influenced by ischemic preconditioning, but hypoxia-inducible genes were not. [Copyright &y& Elsevier]