Reactive Oxygen Species and p38MAPK Have a Role in the Smad2 Linker Region Phosphorylation Induced by TGF-β
Journal Title: Iranian Journal of Medical Sciences - Year 2018, Vol 43, Issue 4
Abstract
Background: Transforming growth factor-β (TGF-β) in addition to the C-terminal region can phosphorylate receptor-regulated Smads (R-Smads) in their linker region. The aim of the present study was to evaluate the role of signaling mediators such as NAD(P)H oxidases (reactive oxygen species [ROS] generators), ROS, and ROS-sensitive p38 mitogen-activated protein kinase (p38MAPK) in this signaling pathway in cultured human vascular smooth muscle cells (VSMCs). Methods: The present in vitro study was performed on human VSMCs. Proteins were detected by western blotting utilizing an anti-phospho-Smad2 (Ser245/250/255) rabbit polyclonal antibody and a horseradish peroxidase-labeled secondary antibody. Glyceraldehyde-3-phosphate dehydrogenase was used as a loading control. The phospho-Smad2 linker region (pSmad2L) was detected in all the experimental groups: a control group (untreated group), a group treated with TGF-β (2 ng/mL), and a group treated with TGF-β plus different inhibitors. The data were normalized and presented as mean±SEM. The statistical analyses were performed using SPSS, version 16.0, and the nonparametric Kruskal–Wallis test. A P value smaller than 0.05 was considered statistically significant. Results: The VSMCs treated with TGF-β (2 ng/mL) showed a time-dependent increase in the pSmad2L level. The highest level was observed at 15 minutes (P=0.03). The inhibitors of NAD(P)H oxidases (diphenyleneiodonium and apocynin) (P=0.04), ROS scavenger (N-acetylcysteine) (P=0.04), and p38MAPK inhibitor (SB-202190) (P=0.04) were able to reduce the increased level of the pSmad2L by TGF-β. Conclusion: Our results suggested that NAD(P)H oxidases played an important role in the Smad2L phosphorylation in the human VSMCs. Furthermore, our results confirmed that ROS and p38MAPK were involved in this signaling pathway. Thus, TGF-β via a ROS-dependent mechanism can transmit its signals to the pSmad2L.
Authors and Affiliations
Reyhaneh Niayesh Mehr, Alireza Kheirollah, Faezeh Seif, Parisa Dayati, Hossein Babaahmadi Rezaei
High Prevalence of Vitamin D Deficiency among Iranian Population: A Systematic Review and Meta-Analysis
Background: The prevention and correction of vitamin D deficiency requires a precise depiction of the current situation and identification of risk factors in each region. The present study attempted to determine these en...
Intralesional Injection of the Measles–Mumps–Rubella Vaccine into Resistant Palmoplantar Warts: A Randomized Controlled Trial
Background: Common resistant-to-therapy warts pose a challenge to both clinicians and patients. Among many destructive and immunotherapeutic options, no single, fully effective treatment has been suggested yet. Many inve...
Urban-Rural Differences in the Prevalence of Self-Reported Diabetes and its Risk Factors: The WHO STEPS Iranian Noncommunicable Disease Risk Factor Surveillance in 2011
The high prevalence of diabetes in Iran and other developing countries is chiefly attributed to urbanization. The objectives of the present study were to assess the prevalence of self-reported diabetes and to determine i...
Subtypes of Benign Breast Disease as a Risk Factor for Breast Cancer: A Systematic Review and Meta-Analysis Protocol
Breast cancer is a multifactorial disease. Benign breast disease (BBD) is one of the most important risk factors for breast cancer. The etiology of BBD is unknown. It is divided into nonproliferative and proliferative di...
Optimization of the Static Human Osteoblast/Osteoclast Co-culture System
Osteoblasts (OBs) and osteoclasts (OCs) are 2 major groups of bone cells. Their cell-to-cell interactions are important to ensure the continuity of the bone-remodeling process. Therefore, the present study was carried ou...