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Published on: June 14, 2016
Regulation of PMA-induced MUC5AC expression by heparin in human bronchial epithelial cells
Qi Li1, Rui Xia Lei, Xiang Dong Zhou
1Department of Respiratory Medicine, The Second Affiliated Hospital, Chongqing Medical University, Yuzhong District, Chongqing, China.
Abstract:
Mucus hypersecretion is a major pathophysiologic feature in chronic inflammatory airway diseases. Oxidative stress plays a pivotal role in this process. Recent studies have found that heparin has antioxidant effects which can reduce free radical damage. Here, we hypothesized that heparin has some influence on the expression of mucin 5AC (MUC5AC) induced by phorbol myristate acetate (PMA) in a bronchial epithelial cell line (HBE16), also we have investigated the potential mechanism involved in the process. We found that ROS, the mRNA of Duox1, EGFR and MUC5AC, as well as the protein levels of Duox1, p-EGFR, EGFR, and MUC5AC in the PMA group were significantly increased when compared with the control group (all P < 0.01). After pretreatment with heparin however, there was a significant decrease in ROS levels, the mRNA of Duox1, EGFR, and MUC5AC, and the protein levels of Duox1, p-EGFR, EGFR, and MUC5AC, when compared with the PMA group (all P < 0.01). MUC5AC protein in the supernatant was inhibited in a dose-dependent manner by heparin. Pretreatment with DMTU resulted in a significant decrease in ROS content, the mRNA of Duox1, EGFR, and MUC5AC as well as the protein levels of Duox1, p-EGFR, EGFR, and MUC5AC when compared with the PMA group (all P < 0.01). When cells were pretreated with both heparin and DMTU, there was a further reduction in ROS content, the mRNA of Duox1, EGFR, and MUC5AC as well as the protein levels of Duox1, p-EGFR, EGFR, and MUC5AC, when compared with either the PMA group, heparin group, or DMTU group (all P < 0.01). Our results show that PMA can induce MUC5AC expression by activation of the Duox1-ROS-TACE-TGF-α-EGFR signaling pathway. Heparin can decrease the level of Duox1, ROS production and block the PMA-induced activation of EGFR, thus inhibiting the overexpression of mucin MUC5AC in a dose-dependent manner. In addition to reducing ROS production, heparin may also inhibit the expression of MUC5AC through other signal mechanisms.
Insights
Heparin reduces mucus hypersecretion in airway diseases by inhibiting the Duox1-ROS-EGFR pathway. This study demonstrates heparin
Area of Science:
- Cell Biology
- Molecular Biology
- Respiratory Medicine
Background:
- Mucus hypersecretion is a key feature of chronic inflammatory airway diseases.
- Oxidative stress significantly contributes to mucus overproduction.
- Heparin exhibits antioxidant properties, suggesting a potential role in mitigating airway inflammation.
Purpose of the Study:
- To investigate the effect of heparin on mucin 5AC (MUC5AC) expression induced by phorbol myristate acetate (PMA) in bronchial epithelial cells.
- To elucidate the underlying molecular mechanisms, including the Duox1-ROS-EGFR signaling pathway.
Main Methods:
- Utilized the HBE16 bronchial epithelial cell line.
- Administered PMA to induce MUC5AC expression and oxidative stress.
- Pretreated cells with heparin and DMTU (an antioxidant) to assess their effects on ROS, mRNA, and protein levels of key molecules (Duox1, EGFR, MUC5AC).
Main Results:
- PMA significantly increased reactive oxygen species (ROS), Duox1, EGFR, and MUC5AC expression.
- Heparin pretreatment dose-dependently reduced ROS, Duox1, EGFR activation (p-EGFR), and MUC5AC levels.
- Combined heparin and DMTU treatment showed a synergistic inhibitory effect on these markers.
Conclusions:
- PMA induces MUC5AC expression via the Duox1-ROS-TACE-TGF-α-EGFR pathway.
- Heparin inhibits PMA-induced MUC5AC overexpression by reducing Duox1, ROS production, and blocking EGFR activation.
- Heparin's protective effects may involve additional signaling pathways beyond ROS reduction.
