Modulation of expression of endothelial intercellular adhesion molecule-1, platelet-endothelial cell adhesion molecule-1, and vascular cell adhesion molecule-1 in aortic arch lesions of apolipoprotein E-deficient compared with wild-type mice.

Human vascular adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1), platelet-endothelial cell adhesion molecule-1 (PECAM-1), and vascular cell adhesion molecule-1 (VCAM-1), are thought to play a critical role in the homing of leukocytes to sites of atherosclerotic lesions. However, very little is known about the expression of adhesion molecules in the vasculature of mice models, such as apolipoprotein E knockout (apoE(-/-)) mice, the lesions of which closely mimic human atherosclerotic lesions. This study has first quantitatively characterized the mean expression of endothelial adhesion molecules, lining the whole vessel intimal circumference, over a period of time (0 to 20 weeks of diet) in aortic arch lesions of male apoE-deficient compared with wild-type (C57BL/6) mice. These animals were fed a chow or a cholesterol-rich diet. ApoE(-/-) animals showed first an increase (at 6 weeks) and then a reduction (at 16 weeks) in the mean expression of ICAM-1 (P<0.05) and PECAM-1 (P<0.05) but not VCAM-1 levels. Such modulation of the mean expression of adhesion molecules was not observed in wild-type mice. Confirmation of immunohistochemistry results on ICAM-1 was obtained by Northern blots performed on the aortic arch of apoE and C57BL6 chow-fed mice over a period of 20 weeks. Moreover, the presence of VCAM-1 was also confirmed at the RNA level, on aortas of control and apoE mice, by reverse transcription-polymerase chain reaction. In the second part of the study, we assayed the levels of adhesion molecules, in different types of histologically defined atherosclerotic lesions, in apoE(-/-) animals fed for 20 weeks. All 3 adhesion molecules (ICAM-1, PECAM-1, and VCAM-1) were observed to be reduced in fibrofatty and complex lesions but not in fatty streaks or in areas without lesions. These results indicate that the expression of these adhesion molecules in apoE-deficient animals varies with the evolution of the plaque from a fatty to a fibrous stage.

Acute hyperglycaemia induces changes in the transcription levels of 4 major genes in human endothelial cells: macroarrays-based expression analysis.

Hyperglycaemia, in insulin-dependent or independent diabetes mellitus, promotes endothelial cell (EC) dysfunction and is a major factor in the development of macro- or microvascular diseases. The mechanisms and the disease-related genes in vascular diseases resulting from hyperglycaemia are poorly understood. Macroarrays. bearing a total of 588 cDNA known genes, were used to analyze HUVEC gene transcription subjected to 25 or 5-mM glucose for 24 h. Isolated mRNA derived from treated first passage HUVEC were reverse transcribed, 32P labeled, and hybridized to the cDNA macroarrays. Results show that acute hyperglycaemia induces an up-regulation of seven major genes, four of which were not previously reported in the literature. Northern blot analyses, performed on these 4 genes, confirm macroarrays results for alphav, beta4, c-myc, and MUC18. Moreover, time course analysis (0, 2, 4, 8, 2, 16, 24 h) of alphav, beta4 c-myc, and MUC18 mRNA expression, observed by northern blot assays, showed a peak at time points situated between 2 to 8 h. The 3 other genes (ICAM-1, beta1, and IL-8), were shown by others to be significantly upregulated after glucose stimulation. Furthermore, ELISA assays performed on the supernatant of HUVEC culture medium showed a significant increase of IL-8 for cells treated with 25-mM compared to 5-mM glucose. Identified genes, upregulated in endothelial cells as a result of acute hyperglycaemia, may serve as therapeutic or diagnostic targets in vascular lesions present in diabetic patients. These results also demonstrate the use of cDNA macroarrays as an effective approach in identifying genes implicated in a diseased cell.

Increased ICAM-1 and PECAM-1 transcription levels in the heart of Apo-E deficient mice in comparison to wild type (C57BL6).

Adhesion molecules and chemoattractants are thought to play a critical role in the homing of leukocytes to sites of vascular lesions. Apo-E deficiency in mice creates an atherosclerotic model that mimics vascular lesions in man. Little is known on the effect of Apo-E deficiency on expression of adhesion molecules in the hearts of these animals. In this study, male C57BL6 and Apo-E deficient mice were fed a chow diet over periods of time (0 to 20 weeks). The transcription levels of major adhesion molecules (ICAM-1, PECAM-1), present in the heart, were followed by northern blots. Immunohistochemistry was used to localize these adhesion molecules in the heart. Results show a significant increase in gene transcription levels of ICAM-1 and PECAM-1 in Apo-E animals, but not wild type, at 16 and 20 weeks of chow diet. Such increase in levels of transcription was not observed in younger Apo-E and C57BL6 animals (0, 6 weeks of diet). ICAM-1 and PECAM-1 were strongly expressed in the endocardium and heart microvessels. In contrast, VCAM-1 was poorly stained, with only an occasional expression on the endocardium and arterioles. Enhanced gene expression levels of heart ICAM-1 and PECAM-1 observed in Apo-E deficient mice, but not in control animals, appears to induce the initial stages of an inflammatory reaction. Such observations, not previously reported, may induce heart vascular remodeling.

Identification and cloning of a new gene (2A3-2), homologous to human translational elongation factor, upregulated in a proliferating rat smooth muscle cell line and in carotid hyperplasia.

Smooth muscle cells (SMCs), before migration and proliferation in the intima of the vessel wall, change from a normal contractile to a pathological proliferating phenotype. The molecular regulatory mechanisms implicated in such phenotypic changes remain poorly understood. In this study, using differential display, we have isolated for the first time a new gene (2A3-2) that is overexpressed in a rapidly proliferating, but not synthetic, rat SMC line. This was further confirmed by northern blot performed on the 2 cell types. Moreover, balloon catheter injury of rat carotids showed, by a virtual northern technique, an upregulation of this new gene in hyperplasia vessels. This new gene (2A3-2, 1.2 kb) was present in skeletal muscle, heart, aorta, lung, liver, kidney, and spleen. In addition, 5' rapid amplification of cDNA ends (5' RACE) allowed the cloning and sequencing of this 1.2-kb gene. Comparison of this newly identified gene sequence with data banks showed a strong homology to human and bovine mitochondrial translational elongation factor. The 2A3-2 gene, identified in this study, may play a vital role in the cascade of events implicated in switching SMC phenotype from a quiescent to a proliferate one.