PM2.5 Exposure and Asthma Development: The Key Role of Oxidative Stress

Figure 3

Oxidative stress in asthma airway remodeling. In asthma, eosinophils and airway epithelial cells are the main source of the profibrotic cytokine TGF-β, which can stimulate ROS production by activating membrane-related oxidase and inhibiting antioxidant enzymes. TGF-β can induce the activity of NAPDH oxidase (NOX) through a variety of signaling pathways, including the SMAD pathway, PI3K pathway, and MAPK pathway, and inhibit the expression of GSH, SOD, and other antioxidant enzymes. Furthermore, TGF-β can regulate autophagy by the PI3K pathway, which is crucial for the activation of myofibroblasts and smooth muscle cells. GSH: glutathione; SOD: superoxide dismutase; MAPK: mitogen-activated protein kinase; NOS2: nitric oxide synthase 2; NO: nitric oxide.