Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 19 1 2020 02 01 84 93 EN Amirhooman Asadi Veterinary Medicine, Faculty of Veterinary Medicine, Karaj Branch, Islamic Azad University, Karaj, Iran Davood Yaghobi Nezhad Department of Agriculture Biotechnology, Faculty of Agriculture, Payame Noor University, Tehran, Iran Amirreza Rafie Javazm Student Research Committee, Faculty of Nursing and Midwifery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Parisa Khanicheragh Department of Clinical Biochemistry, Lorestan University of Medical Sciences, Khorram abad, Iran Ladan Mashouri Department of Genetics, Faculty of Science, Shahrekord University, Shahrekord, Iran Fatemeh Shakeri Jahrom University of Medical Sciences, Jahrom, Iran Mojtaba Abbasi Veterinary Medicine, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran Mahya Sadat Afrazian Department of Biology, Faculty of Basic Sciences, University of Shiraz, Shiraz, Iran Zahra Niknam Student Research Committee, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapor University of Medical Science, Ahvaz, Iran Omid Abazari Department of Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran 2019 07 28 2019 08 15 Transforming growth factor-β (TGF-β) induces pro-inflammatory cytokines expression including interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) and these cytokines are associated with the development of atherosclerosis. Curcumin has anti-atherogenic effects and anti-inflammatory properties in the vascular wall, but the relative mechanisms are almost unknown. In the present study, we investigate the effect of curcumin on modulating the pro-inflammatory action of TGF-β in human vascular smooth muscle cells (VSMCs) and its molecular mechanisms. Cultured VSMCs were seeded into several groups: a control group (untreated group), a group treated with TGF-β, and several groups treated with TGF-β plus inhibitors. The cells were pre-treated with diphenyleneiodonium chloride, DPI, (20 μM), curcumin (5, 10 and 20 μM) and N-Acetyl-L-Cysteine, NAC, (10 mM) and then TGF-β (5 ng/mL) was added to the culture medium. The mRNA levels of IL-6 and TNF-α were detected by quantitative Real-Time Polymerase Chain Reaction. For monitoring the Smad2 linker region phosphorylation (pSmad2L), the western-blotting technique was applied and reactive oxygen species (ROS) generation was measured by utilizing 2′,7′-dichlorofluorescein diacetate-based assay. TGF-β increased the mRNA expression of IL-6 (p=0.02 and p=0.001) and TNF-α (p =0.014 and p = 0.001) in a time-dependent manner, ROS production (p=0.03) and Smad2L phosphorylation (p=0.015). Pre-treatment with curcumin, DPI and NAC inhibited TGF-β–induced IL-6 (p=0.04) and TNF-α (p=0.001) mRNA expression, Smad2L phosphorylation (p=0.02) and ROS production (0.03). Pharmacological inhibition by Curcumin blocks TGF-β–induced ROS production, Smad2L phosphorylation, and IL-6 and TNF-α mRNA expression in human VSMCs. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/2472