Deficiency of the long pentraxin PTX3 promotes vascular inflammation and atherosclerosis.

BACKGROUND: Immune responses participate in several phases of atherosclerosis; there is, in fact, increasing evidence that both adaptive immunity and innate immunity tightly regulate atherogenesis. Pentraxins are a superfamily of acute-phase proteins that includes short pentraxins such as C-reactive protein or long pentraxins such as PTX3, a molecule acting as the humoral arm of innate immunity. To address the potential role of PTX3 in atherogenesis, we first investigated the expression of PTX3 during atherogenesis, generated double-knockout mice lacking PTX3 and apolipoprotein E, and then studied the effect of murine PTX3 deficiency on plasma lipids, atherosclerosis development, and gene expression pattern in the vascular wall. METHODS AND RESULTS: PTX3 expression increases in the vascular wall of apolipoprotein E-knockout mice from 3 up to 18 months of age. Double-knockout mice lacking PTX3 and apolipoprotein E were fed an atherogenic diet for 16 weeks. Aortic lesions were significantly increased in double-knockout mice and mice heterozygous for PTX3 compared with apolipoprotein E-knockout mice. Mice lacking PTX3 showed a more pronounced inflammatory profile in the vascular wall as detected by cDNA microarray and quantitative polymerase chain reaction analysis and an increased macrophage accumulation within the plaque. Finally, lesion size correlated with the number of bone marrow monocytes. CONCLUSIONS: PTX3 has atheroprotective effects in mice, which, in light of the cardioprotective effects recently reported, suggests a cardiovascular protective function of the long pentraxin 3 through the modulation of the immunoinflammatory balance in the cardiovascular system.

Long pentraxin 3, a key component of innate immunity, is modulated by high-density lipoproteins in endothelial cells.

OBJECTIVE: High-density lipoproteins (HDL) are endowed with cardiovascular protective activities. In addition to their role in reverse cholesterol transport, HDL exert several beneficial effects on endothelial cells, including the induction of endothelial nitric oxide synthase and prostacyclin release, and the control of the immune and inflammatory response. METHODS AND RESULTS: To identify possible mechanisms involved in these effects we investigated the modulation of the expression of acute phase proteins of the pentraxin superfamily, such as C-reactive protein (CRP), serum amyloid P component protein (SAP), and the long pentraxin 3 (PTX3) by HDL in human endothelial cells. HDL induced PTX3 mRNA expression and protein release, whereas no effect was observed on CRP and SAP expression. This effect was mainly dependent on the activation of the lysosphingolipids receptors-PI3K/Akt axis and was mimicked by sphingosine 1 phosphate and other S1P mimetics. This observation was confirmed in vivo; indeed an increased expression of PTX3 mRNA was detected in the aorta of transgenic mice overexpressing human apoA-I, compared to apoA-I knock-out mice. Furthermore, plasma levels of PTX3 significantly increased in C57BL/6 mice injected with HDL. CONCLUSIONS: These data suggest that part of the atheroprotective effects of HDL could result from the modulation of molecules that act as sensors of the immunoinflammatory balance in the vascular wall.

Anti-inflammatory and anti-atherogenic effects of cathechin, caffeic acid and trans-resveratrol in apolipoprotein E deficient mice.

A strong negative correlation between polyphenols consumption and coronary heart disease has been extensively documented. These results prompted investigations on the mechanisms responsible for polyphenols effects in cardiovascular disease. The aim of this work was to investigate in apoE KO mice the effect of P183/1 (a mixture of cathechin, caffeic acid and resveratrol) on atherosclerosis and gene expression patterns in the vascular wall. ApoE KO mice were fed a diet supplemented with P183/1, 40 and 160 mg/kg body weight/day for 8 weeks. The supplementation with the high dose of P183/1 significantly reduced the presence of atherosclerotic plaque by 40 and 36% in the aortic sinus and in the ascending aorta, respectively. This reduction was associated with a reduced expression of markers for macrophages, lymphocytes (both Th1 and Th2) and of MCP-1, MIP-1alpha, MIP-1beta, CCR1, CCR2 and ET1 in the vascular wall. In conclusion, P183/1 supplementation significantly decreases atherosclerosis in ApoE KO mice by affecting inflammatory cells recruitment and expression of pro-inflammatory chemokines in the vascular wall.