Inhibition of NADPH oxidase suppresses cerulein-induced inflammatory signaling in pancreatic acinar AR42J cells

Abstract

[한글]

활성산소종은 췌장 선세포에서 췌장염의 발달단계, 핵전사인자인 NF-κB의 활성화와 염증성 cytokine의 발현에 중요한 조절인자로 고려되어지고 있다. 이전 연구에서 췌장 선세포에서 cerulein에 의해 NADPH oxidase가 활성화됨을 확인하였고, 이로 인해 활성산소가 생성됨을 확인하였다. 본 연구에서는 췌장 선세포에서 cerulein에 의해서 유도되는 염증성 cytokine발현을 유도하는 신호전달 기전에서 NADPH oxidase의 역할에 대해서 알아보고자 하였다.

연구결과 (1) Cerulein에 의해서 염증매개 단백인 JAK2/STAT3과 핵전사 인자인 NF-κB가 활성화 되었으며, 대표적인 염증성 cytokine인 IL-1β and TGF-β1 또한 발현되었다. (2) NADPH oxidase 억제제인 DPI와 NADPH oxidase subnits에 대한 AS ODNs을 처치하여 cerulein으로 활성화되는 JAK2/STAT3, ERK/JNK, NF-κB의 활성화, IL-1β 와 TGF-β1의 발현을 억제하였다. (3) 부가적으로 JAK2 억제제인 AG490을 처치하였을 때 ERK/JNK, NF-κB 활성화, IL-1β 와 TGF-β1의 발현이 억제됨을 확인 하였다. 이는 cerulien으로 유도되는 NADPH oxidase가 JAK2/STAT3, ERK/JNK 신호전달기전을 통해 염증성 cytokine이 발현됨을 시사한다.

본 연구를 통하여 NADPH oxidase는 급성 췌장염 진전을 막기 위한 신약 개발에 표적물질일 것으로 생각된다.

[영문]Reactive oxygen species (ROS) are important pathogenic factors in the development of pancreatitis and activate NF-κB, a regulator of inflammatory cytokine gene expression, in pancreatic acinar cells. Previous results demonstrated that cerulein induces activation of NADPH oxidase in pancreatic acinar AR42J cells and produces ROS. Present study was designed to elucidate the role of NADPH-oxidase on cerulein-induced signaling cascade leading to inflammatory cytokine expression such as IL-1β and TGF-β1 in pancreatic acinar AR42J cells.

As a result, JAK2/STAT3, ERK/JNK and NF-κB were activated by cerulein in AR 42J cells. IL-1β and TGF-β1 expressions increased by cerulein. Cerulein-activated JAK2/STAT3, ERK/JNK and NF-κB were inhibited by NADPH oxidase inhibitor DPI and by transfection with AS ODNs for NADPH oxdase subunits in AR42J cells. Cerulein-induced expression of IL-1β and TGF-β1 were suppressed by DPI and by transfection with AS ODNs for NADPH oxidase subunits in AR 42J cells. Further, ceruelin-induced expression of IL-1β and TGF-β1, and NF- B activation were inhibited by JAK2 inhibitor AG490 in AR 42J cells, which indicates that the activation of ERK/JNK, NF- B and the expression of IL-1β, and TGF-β1 are mediated by activated JAK2. These results suggest that cerulein-stimulated NADPH-oxidase mediates the expression of inflammatory cytokine such as IL-1β and TGF-β1 by signaling pathways that involve JAK2/STAT3 and ERK/JNK as signaling molecules.

In conclusion, NADPH oxidase mediates the inflammatory signaling involving the activation of JAK/STAT, ERK/JNK and NF- B, and results in the induction of IL-1β and TGF-β1 expression in pancreatic acinar AR42J cells. NADPH oxidase may be the target molecule for new drug to prevent the progression of acute pancreatitis.