Lipoxin A and Serum Amyloid a Differentially Modulate Phospholipase D in Human Fibroblast-Like Synoviocytes

Lipoxin A 4 (LXA 4 ) and scrum amyloid A (SAA) are endogenous negative and positive modulators of inflammation, respectively. Both molecules bind the shared lipoxin A 4 receptor (ALX) and elicit opposing effects on the production of inflammatory cytokines and matrix metalloproteinases. The aim of these studies is to examine the divergence of the intracellular signaling pathways triggered by lipid LXA 4 (1 nM) and protein SAA (200 nM) ligands of ALX. Phospholipase D (PLD) is a phosphohydrolase enzyme that catalyzes the generation of phosphatidic acid (PA) from membrane phospholipids. Our results showed that in fibroblast-like synoviocytes, activation of PLD occurred only in response to LXA 4 , and not SAA. PA (30 μM) mimicked LXA 4 and demonstrated inhibition of IL-8 production induced by SAA or interleukin-1β. In sharp contrast to LXA 4 , SAA confirmed the stimulation of IL-8 release as determined previously. Taken together, these findings suggest that two physiologic ligands sharing the common ALX receptor, LXA 4 and SAA, differentially regulate the level of PLD activation and differentially modulate IL-8. These results may have important implications for understanding the regulation of inflammatory responses under physiologic and pathological conditions

High Avidity Anti-β2-Glycoprotein i Antibodies Activate Human Coronary Artery Endothelial Cells and Trigger Peripheral Blood Mononuclear Cell Migration

Anti-β2-glycoprotein I antibodies (aβ2GPI) represent a potential pathogenic candidate for coronary artery diseases. High avidity aβ2GPI (HAv aβ2GPI) are known to be associated with thrombotic and obstetric manifestations in patients with antiphospholipid syndrome, who are also susceptible to the development of premature atherosclerosis. However, there is little information about how human coronary artery endothelial cells (HCAEC) are affected by HAv aβ2GPI. The purpose of our study was to evaluate the pathophysiological effects of HAv aβ2GPI on HCAEC and determine their influence on cytokine expression and migration of peripheral blood mononuclear cells. Following the two hit hypothesis, we co-stimulated HAv aβ2GPI-treated HCAEC in the presence and absence of the acute phase protein serum amyloid A (SAA). HAv aβ2GPI induced in vitro HCAEC dysfunction, through the ERK1/2 signaling pathway, promoted the expression of chemokines (MCP-1, GROα and IL-8) and IL-6, which led to the attraction and migration of peripheral blood mononuclear cells. These effects were potentiated and intensified in conditions with SAA, indicating that HAv aβ2GPI, in the presence of physiological concentrations of acute-phase proteins represent pathogenic autoantibodies, which could lead to the development of premature atherosclerosis and/or thrombosis development

Analysis of Drug Effects on Primary Human Coronary Artery Endothelial Cells Activated by Serum Amyloid A

Background. RA patients have a higher incidence of cardiovascular diseases compared to the general population. Serum amyloid A (SAA) is an acute-phase protein, upregulated in sera of RA patients. Aim. To determine the effects of medications on SAA-stimulated human coronary artery endothelial cells (HCAEC). Methods. HCAEC were preincubated for 2 h with medications from sterile ampules (dexamethasone, methotrexate, certolizumab pegol, and etanercept), dissolved in medium (captopril) or DMSO (etoricoxib, rosiglitazone, meloxicam, fluvastatin, and diclofenac). Human recombinant apo-SAA was used to stimulate HCAEC at a final 1000 nM concentration for 24 hours. IL-6, IL-8, sVCAM-1, and PAI-1 were measured by ELISA. The number of viable cells was determined colorimetrically. Results. SAA-stimulated levels of released IL-6, IL-8, and sVCAM-1 from HCAEC were significantly attenuated by methotrexate, fluvastatin, and etoricoxib. Both certolizumab pegol and etanercept significantly decreased PAI-1 by an average of 43%. Rosiglitazone significantly inhibited sVCAM-1 by 58%. Conclusion. We observed marked influence of fluvastatin on lowering cytokine production in SAA-activated HCAEC. Methotrexate showed strong beneficial effects for lowering released Il-6, IL-8, and sVCAM-1. Interesting duality was observed for NSAIDs, with meloxicam exhibiting opposite-trend effects from diclofenac and etoricoxib. This represents unique insight into specific responsiveness of inflammatory-driven HCAEC relevant to atherosclerosis

Atorvastatin in stable angina patients lowers CCL2 and ICAM1 expression: Pleiotropic evidence from plasma mRNA analyses.

Objective: Statin pleiotropy is still an evolving concept, and the lack of clarity on this subject is due at least in part to the lack of a definitive biomarker for statin pleiotropy. Using plasma mRNA analysis as a novel research tool for the non-invasive in vivo assessment of gene expression in vascular beds, we hypothesised that atorvastatin lowers the plasmamRNA level from statin pleiotropy-target genes, and the reduction is independent of the reduction of low-density lipoprotein cholesterol (LDL-C). Design and methods: Forty-four patients with stable angina received atorvastatin therapy (20 mg/day, 10 weeks). Plasma chemokine (C-C motif) ligand 2 (CCL2) and intercellular adhesion molecule-1 (ICAM1) mRNA levels and their protein concentrations (MCP-1, sICAM-1) were analysed before and after the treatment. Plasma vascular adhesion molecule-1 (sVCAM-1) concentrations were also analysed. Results: Atorvastatin lowered plasma mRNA levels (CCL2: −31.76%, p = 0.037; ICAM1: −34.09%, p b 0.001) and MCP-1 protein concentration (−18.88%, p = 0.008) but did not lower sICAM-1 and sVCAM-1 protein concentrations, and the decreases appeared to be independent from the lowering of LDL-C. The plasma mRNA levels correlated with their protein concentrations following statin treatment only. Conclusion: Our results significantly strengthen the clinical evidence in support of statin pleiotropy. Furthermore, this unique simultaneous measurement of plasma mRNAs and their protein concentrations offers an advanced non-invasive in vivo assessment of the circulation patholog