硫醇氧化還原蛋白調控香菸暴露對於人類呼吸道上皮細胞之重塑因子基因表現

Thioredoxin Modulates Cigarette Smoke-Induced Expression of Remodeling Factors in Human Airway Epithelial Cells

黃依齡(Yi-Ling Huang)

指導教授 ： 陳家揚 ； 宋鴻樟 ； 莊淳宇

國立臺灣大學/公共衛生學院/環境衛生研究所/博士(2009年)

https://doi.org/10.6342/NTU.2009.02625

摘要

吸煙過程中產生之活性氧化物種(reactive oxidative species; ROS)會造成呼吸道上皮細胞氧化傷害，促使細胞修復。持續性的細胞修復會使呼吸道重塑(airway remodeling)和不可逆的氣道受限(airflow limitation)。硫醇氧化還原蛋白(thioredoxin; TRX)為氧化還原蛋白，具有清除ROS特性進而減少氧化壓力。本研究目的欲瞭解TRX如何調控香菸暴露所導致之氧化傷害及其對於呼吸道重塑因子(airway remodeling factor)和細胞傳遞訊息(signal transduction)之影響。
本研究分別以人類呼吸道細胞和具有大量表現TRX呼吸道細胞，暴露不同劑量和時間的香菸萃取物，進而探討TRX參與調控呼吸道重塑因子表現之情形。結果顯示當人類呼吸道上皮細胞受到高濃度香菸暴露時，會產生內生性ROS和使TRX基因表現下降而導致細胞凋亡(apoptosis)；呼吸道上皮細胞暴露低濃度香菸則增加TRX基因表現。此外，香菸暴露增加重塑因子基因如transforming growth factor (TGF)-β1、epidermal growth factor receptor (EGFR)和cyclin-dependent kinase inhibitor (p21)之表現量，但抑制matrix metalloproteinases (MMP)-9。
大量表現TRX之呼吸道上皮細胞暴露香菸時，能減少ROS產生，並透過apoptosis signal regulating kinase (ASK)-1去活化及抑制 p38和c-Jun N-terminal kinase (JNK)表現，使細胞免於走向凋亡。呼吸道上皮細胞以TGF-β1抗體中和(neutralization)後再暴露香菸，TRX表現量受到抑制，使得MMP-9、EGFR和p21基因表現下降。此結果顯示TRX受到TGF-β1調控，進而使MAPK及MMP-9蛋白去活化。本研究證實轉殖的TRX具有氧化還原能力，且當TRX大量表現時會減少香菸暴露所造成之氧化傷害。此研究結果得知TRX抵禦氧化傷害之基因調控機制，可提供後續肺部損害相關研究之參考。

關鍵字

香菸暴露 ； 活性氧化物種 ； 人類支氣管上皮細胞 ； 硫醇氧化還原蛋白 ； 呼吸道重塑因子

並列摘要

Cigarette smoke (CS) generates reactive oxygen species (ROS) that produces oxidative damage to bronchial epithelial cells. Prolonged repair responses lead to airway remodeling and irreversible airflow limitation. Cigarette smoke may cause bronchial epithelium damage and orchestrate airway remodeling resulting from activation of epithelial repair and mediator release. Thioredoxin (TRX) has anti-oxidation capability against oxidative stress, and involves in cell growth and differentiation. The aim of this study was to investigate how TRX mediates CS-induced oxidative damage and modulated any onset/progression of airway remodeling and its downstream mitogen-activated protein kinase (MAPK) in human airway epithelial cells.
Normal human epithelial cells (BEAS-2B) and thioredoxin over-expressing cells were used for various experiments including different doses and periods of CS exposure. Results of this study showed that high-dose CS extract stimulated ROS generation and decreased TRX expression resulting in apoptosis of BEAS-2B cells. Otherwise, BEAS-2B cells exposure to low-dose CS increased TRX expression. Additionally, CS exposure interfered with gene expression of remodeling factors such as activation of the transforming growth factor (TGF)-β1, epidermal growth factor receptor (EGFR) and cyclin-dependent kinase inhibitor (p21), but attenuated of matrix metalloproteinases (MMP)-9.
BEAS-2B cells over-expressing TRX suppressed CS-induced apoptosis through reduction of ROS generation, inactivation of apoptosis signal regulating kinase (ASK)-1, and attenuation of p38 and c-Jun N-terminal kinase (JNK). After being neutralized with anti-TGF-β1 antibody, TRX over-expressing cells exposed CS decreased gene expression of MMP-9, EGFR and p21. It suggests that TGF-β1 regulated TRX expression may further prevent the underlying CS-induced airway remodeling through MAPK activation and MMP-9 augmentation. This study demonstrated that the transfected TRX gene had redox capacity to reduce CS-induced oxidative damage. The mediating mechanism of TRX against CS-induced damage can be applied in further preventive and therapeutic studies.

並列關鍵字

cigarette smoke ； reactive oxidative species ； human bronchial epithelial cells ； thioredoxin ； remodeling factors

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