Computational identification of potential transcriptional regulators of TGF-ß1 in human atherosclerotic arteries.

TGF-ß is protective in atherosclerosis but deleterious in metastatic cancers. Our aim was to determine whether TGF-ß transcriptional regulation is tissue-specific in early atherosclerosis. The computational methods included 5 steps: (i) from microarray data of human atherosclerotic carotid tissue, to identify the 10 best co-expressed genes with TGFB1 (TGFB1 gene cluster), (ii) to choose the 11 proximal promoters, (iii) to predict the TFBS shared by the promoters, (iv) to identify the common TFs co-expressed with the TGFB1 gene cluster, and (v) to compare the common TFs in the early lesions to those identified in advanced atherosclerotic lesions and in various cancers. Our results show that EGR1, SP1 and KLF6 could be responsible for TGFB1 basal expression, KLF6 appearing specific to atherosclerotic lesions. Among the TFs co-expressed with the gene cluster, transcriptional activators (SLC2A4RG, MAZ) and repressors (ZBTB7A, PATZ1, ZNF263) could be involved in the fine-tuning of TGFB1 expression in atherosclerosis.

Regulation of aortic extracellular matrix synthesis via noradrenergic system and angiotensin II in juvenile rats.

CONTEXT: Extracellular matrix (ECM) synthesis regulation by sympathetic nervous system (SNS) or angiotensin II (ANG II) was widely reported, but interaction between the two systems on ECM synthesis needs further investigation. OBJECTIVE: We tested implication of SNS and ANG II on ECM synthesis in juvenile rat aorta. MATERIALS AND METHODS: Sympathectomy with guanethidine (50 mg/kg, subcutaneous) and blockade of the ANG II AT1 receptors (AT1R) blocker with losartan (20 mg/kg/day in drinking water) were performed alone or in combination in rats. mRNA and protein synthesis of collagen and elastin were examined by Q-RT-PCR and immunoblotting. RESULTS: Collagen type I and III mRNA were increased respectively by 62 and 43% after sympathectomy and decreased respectively by 31 and 60% after AT1R blockade. Combined treatment increased collagen type III by 36% but not collagen type I. The same tendency of collagen expression was observed at mRNA and protein levels after the three treatments. mRNA and protein level of elastin was decreased respectively by 63 and 39% and increased by 158 and 15% after losartan treatment. Combined treatment abrogates changes induced by single treatments. DISCUSSION AND CONCLUSION: The two systems act as antagonists on ECM expression in the aorta and combined inhibition of the two systems prevents imbalance of mRNA and protein level of collagen I and elastin induced by single treatment. Combined inhibition of the two systems prevents deposit or excessive reduction of ECM and can more prevent cardiovascular disorders.

Transforming growth factor-ß1 inhibits interleukin-1ß-induced expression of inflammatory genes and Cathepsin S activity in human vascular smooth muscle cells.

OBJECTIVE AND DESIGN: This study investigated the opposite mechanisms by which IL-1ß and TGF-ß1 modulated the inflammatory and migratory phenotypes in cultured human intimal vascular smooth muscle cells vSMCs. MATERIALS AND TREATMENT: Primary human vSMCs, obtained from twelve hypertensive patients who underwent carotid endarterectomy, were incubated for 24 hours with either 40 pM TGF-ß1, or 1 nmol/L IL-1ß, or their combination in presence or absence of anti-TGF-ß neutralizing antibody. METHODS: The expression levels of matrix metalloproteases and their inhibitors, and the elastolytic enzyme cathepsin S (CTSS) and its inhibitor cystatin C were evaluated with RT-PCR. CTSS activity was measured by fluorometry. RESULTS: TGF-ß1 reversed IL-1ß-induced expression of iNOS, CXCL6, IL1R1, MMP12, and CTSS, while upregulated TIMP2 expression. Furthermore, anti-TGF-ß neutralizing antibody abrogated TGF-ß effects. Combination with IL-1ß and TGF-ß1 induced the expression of IL1α, IL1ß, IL1R1, and CTSS, but suppressed CST3 expression. CTSS expression in the combination treatment was higher than that of cells treated with anti-TGF-ß antibodies alone. Moreover, IL-1ß-induced CTSS enzymatic activity was reduced when human vSMCs were co-treated with TGF-ß, whereas this reduction was abrogated by anti-TGF-ß neutralizing antibody. CONCLUSION: TGF-ß1 abrogated IL-1ß-induced expression of inflammatory genes and elastolytic activity in cultured human vSMCs. Thus, TGF-ß1 can play a crucial role in impairing IL-1ß-induced vascular inflammation and damage involved in the etiology of cardiovascular diseases.

[Toxicity of hexachlorobenzene in Meriones unguiculatus: effects on thyroid and liver]. / Toxicité de l'hexachlorobenzène chez Meriones unguiculatus: effets sur la thyroïde et le foie.

The effect of in vivo administered hexachlorobenzene (HCB) on liver and thyroid was studied on Meriones unguiculatus. HCB (1.6, 4, and 16 mg/kg of body weight) has been administered orally to meriones for 30 days. At the end of the experiment, the body weight of the animals did not show significant change. However, the higher dose of HCB treatment led to a pronounced hepatic hypertrophy comparatively to controls. Histological observations revealed many cytomorphological alterations. Cellular necrosis, periportal, and centrolobular vein congestion and cytoplasmic vacuolisation were noted and correlated with the administered doses of HCB. The higher dose of HCB induced modifications in the activities of hepatic transaminases and on thyroid hormones levels: ALAT activity level was more pronounced in males (170+/-24.7 U/l vs. 52.66+/-8.29 U/l in controls) than in females (120+/-12.47 U/l vs. 56+/-5 U/l in controls). However, ASAT activity increased significantly only in females (259+/-29 U/l vs. 244.66+/-18 U/l in controls). Plasma total triiodothyronine (TT3) and total thyroxine (TT4) levels seemed to be sex-dependent in intoxicated animals, since TT4 decreased significantly in males (21.95+/-7.46 nmol/l vs. 40.59+/-1.08 nmol/l in controls) and TT3 in females (1.42+/-0.11 nmol/l vs. 3.96+/-0.48 nmol/l in controls).

Atlas of tissue renin-angiotensin-aldosterone system in human: A transcriptomic meta-analysis.

Tissue renin-angiotensin-aldosterone system (RAAS) has attracted much attention because of its physiological and pharmacological implications; however, a clear definition of tissue RAAS is still missing. We aimed to establish a preliminary atlas for the organization of RAAS across 23 different normal human tissues. A set of 37 genes encoding classical and novel RAAS participants including gluco- and mineralo-corticoids were defined as extended RAAS (extRAAS) system. Microarray data sets containing more than 10 normal tissues were downloaded from the GEO database. R software was used to extract expression levels and construct dendrograms of extRAAS genes within each data set. Tissue co-expression modules were then extracted from reproducible gene clusters across data sets. An atlas of the maps of tissue-specific organization of extRAAS was constructed from gene expression and coordination data. Our analysis included 143 data sets containing 4933 samples representing 23 different tissues. Expression data provided an insight on the favored pathways in a given tissue. Gene coordination indicated the existence of tissue-specific modules organized or not around conserved core groups of transcripts. The atlas of tissue-specific organization of extRAAS will help better understand tissue-specific effects of RAAS. This will provide a frame for developing more effective and selective pharmaceuticals targeting extRAAS.

Physiological regulation of MMPs and tPA/PAI in the arterial wall of rats by noradrenergic tone and angiotensin II.

The interactions between the sympathetic nervous system (SNS) and angiotensin II (ANG II), and their direct effects in vitro on the enzymes involved in vascular extracellular matrix (ECM) degradation, were examined. Rats were treated with guanethidine, losartan or the combined treatments. mRNA, protein and activity of matrix metalloproteinase (MMP)-2 and MMP-9 and mRNA of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) were quantified in abdominal aorta (AA) and femoral artery (FA). Norepinephrine (NE) or ANG II with adrenergic (ß, α1 and α2) or losartan antagonists was tested for MMP mRNA response in cultured vascular smooth muscle cells (VSMCs). Combined treatment enhances the inhibition of MMP-2 mRNA and protein level induced by simple treatment in AA. However MMP-9 in AA and MMP mRNA in FA were reduced in the same order by treatments. MMP activities were not affected by treatments. The t-PA/PAI-1 ratio, which reflects the fibrinolytic balance, remained higher after treatments. In cultured VSMCs, NE induced stimulation of MMP mRNA via α2 and ß adrenergic receptors and MMP-2 activity via ß adrenergic receptors, while ANG II-induced stimulation was abrogated by losartan. Overall, there is a synergic inhibition of both systems on the level of MMP-2 in AA.