NOX4-Derived ROS Promotes Collagen I Deposition in Bronchial Smooth Muscle Cells by Activating Noncanonical p38MAPK/Akt-Mediated TGF-β Signaling.

Binwei Hao,Bing Li,Juan Chen,Yumin Zhou,Wei Hong,Xiaotong Guo,Yanan Zhang,Jieda Cui,Lili Zhang,Jinxi He,Xiaoming Liu,Pixin Ran,Ruiting Sun,Tatiana Victoni

doi:10.1155/2021/6668971

Abstract

Background Airway smooth muscle (ASM) remodeling is a hallmark in chronic obstructive pulmonary disease (COPD). NADPH oxidase 4- (NOX4-) mediated reactive oxygen species (ROS) production plays a crucial role in cell differentiation and extracellular matrix (ECM) synthesis in ASM remodeling. However, the precise mechanisms underpinning its pathogenic roles remain elusive. Methods The expression of NOX4 and TGF-β1 in the airway of the lung was measured in COPD patients and the control group. Cigarette smoke- (CS-) induced emphysema mice were generated, and the alteration of α-SMA, NOX4, TGF-β1, and collagen I was accessed. The changes of the expression of ECM markers, NOX4, components of TGF-β/Smad, and MAPK/Akt signaling in human bronchial smooth muscle cells (HBSMCs) were ascertained for delineating mechanisms of NOX4-mediated ROS production on cell differentiation and remodeling in human ASM cells. Results An increased abundance of NOX4 and TGF-β1 proteins in the epithelial cells and ASM of lung was observed in COPD patients compared with the control group. Additionally, an increased abundance expression of NOX4 and α-SMA was observed in the lungs of the CS-induced emphysema mouse model. TGF-β1 displayed abilities to increase the oxidative burden and collagen I production, along with enhanced phosphorylation of ERK, p38MAPK, and p-Akt473 in HBSMCs. These effects of TGF-β1 could be inhibited by the ROS scavenger N-acetylcysteine (NAC), siRNA-mediated knockdown of Smad3 and NOX4, and pharmacological inhibitors SB203580 (p38MAPK inhibitor) and LY294002 (Akt inhibitor). Conclusions NOX4-mediated ROS production alters TGF-β1-induced cell differentiation and collagen I protein synthesis in HBSMCs in part through the p38MAPK/Akt signaling pathway in a Smad-dependent manner.

Highlights

Chronic obstructive pulmonary disease (COPD) is a major cause of chronic mortality, which accounts for over 3 million annual deaths worldwide [1, 2]
The results showed that 2 ng/mL TGF-β1 significantly upregulated the levels of NOX4 mRNA in human bronchial smooth muscle cells (HBSMCs) at 4 h, which peaked at 12 h and remained high at 36 h (Figure 3(a)), and the increased expression of NOX4 mRNA was induced by 0.5-10 ng/mL TGF-β1 for 24 h (Figure 3(b))
Our previous works revealed an increased expression of NOX4 and TGF-β in the Airway smooth muscle (ASM) of the small airway of the human chronic obstructive pulmonary disease (COPD) lung, which was positively correlated with the severity of airflow limitation [11]

Summary

Introduction

Chronic obstructive pulmonary disease (COPD) is a major cause of chronic mortality, which accounts for over 3 million annual deaths worldwide [1, 2]. NADPH oxidase 4- (NOX4-) mediated reactive oxygen species (ROS) production plays a crucial role in cell differentiation and extracellular matrix (ECM) synthesis in ASM remodeling. The changes of the expression of ECM markers, NOX4, components of TGF-β/Smad, and MAPK/Akt signaling in human bronchial smooth muscle cells (HBSMCs) were ascertained for delineating mechanisms of NOX4-mediated ROS production on cell differentiation and remodeling in human ASM cells. An increased abundance of NOX4 and TGF-β1 proteins in the epithelial cells and ASM of lung was observed in COPD patients compared with the control group. NOX4-mediated ROS production alters TGF-β1-induced cell differentiation and collagen I protein synthesis in HBSMCs in part through the p38MAPK/Akt signaling pathway in a Smad-dependent manner

Methods

Results

Conclusion