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Miaomiao Li,1,* Yue Yuan,1,* Xue Han,2 Xinjuan Liu,1 Weizhen Zhang,2 Jianyu Hao1 1Department of Gastroenterology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, People’s Republic of China; 2Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jianyu Hao, Department of Gastroenterology, Beijing Chao-Yang Hospital, Capital Medical University, No. 8, South Road of Workers Stadium, Chaoyang District, Beijing, 100020, Email haojianyu@ccmu.edu.cn Weizhen Zhang, Department of Physiology and Pathophysiology, Peking University Health Science Center, No. 38, Xueyuan Road, Haidian District, Beijing, 100191, Email weizhenzhang@bjmu.edu.cnBackground: Chronic pancreatitis (CP) is a long-term inflammatory disease of the pancreas that can be caused by various pathogenic factors. Oxidative stress (OS), which is associated with several pancreatic diseases, can induce pancreatic stellate cell (PSC) activation, leading to pancreatic fibrosis. Given the inefficacy of existing treatments for CP, in this study, our objective was to evaluate the therapeutic effect of the antioxidant, mitoquinone (MitoQ).Methods: First, in vivo, we established a CP mouse model via the repeated injection of cerulein. Mice in the MitoQ group simultaneously received MitoQ daily. After 4 weeks of cerulein injection, pancreatic tissues from mice were evaluated by morphological changes and the expression of fibrosis markers. Further, OS in the collected pancreatic tissue samples was evaluated by determining the level of malondialdehyde (MDA) as well as the expression levels and activities of antioxidants. Furthermore, in vitro, the effect of MitoQ on human PSCs (hPSCs) was evaluated based on PSC activation markers and fibrotic phenotypes, and OS in these treated hPSCs was evaluated by measuring reactive oxygen species (ROS), MDA, and anti

Toll-like receptors (TLRs) expressed on mast cells are essential for effective host defense against a wide variety of pathogens. Previous studies have demonstrated that both TLR2 agonists Pam3CSK4 and PGN stimulated IL-8 release in human mast cells. To determine the molecular basis for this phenomenon, we utilized human mast cell line LAD2 cells. We found that only the release of IL-8 stimulated by Pam3CSK4 was TLR2-mediated, which was confirmed by specific TLR2 shRNA. Heterotrimeric G proteins have been previously implicated in TLR signaling in macrophages and monocytes. In the current study, we showed that PamCSK4 induced the activation of MAPKs, NF-kappa B, PI3K-Akt and Ca2+-calcineurin-NFAT signaling cascades in LAD2 cells. G(o) proteins were required for the activation of MAPKs and NF-kappa B in TLR2 stimulated LAD2 cells. Therefore, the genetic depletion of G alpha(o) proteins also led to the reduction of the release of IL-8 in LAD2 cells. Taken together, the data presented here suggest that TLR2 activation in human mast cells promotes the release of inflammatory mediators via distinct signaling pathways that partially depend on the action of G(o) proteins.

Toll-like receptors (TLRs) expressed on mast cells are essential for effective host defense against a wide variety of pathogens. Previous studies have demonstrated that both TLR2 agonists Pam3CSK4 and PGN stimulated IL-8 release in human mast cells. To determine the molecular basis for this phenomenon, we utilized human mast cell line LAD2 cells. We found that only the release of IL-8 stimulated by Pam3CSK4 was TLR2-mediated, which was confirmed by specific TLR2 shRNA. Heterotrimeric G proteins have been previously implicated in TLR signaling in macrophages and monocytes. In the current study, we showed that PamCSK4 induced the activation of MAPKs, NF-kappa B, PI3K-Akt and Ca2+-calcineurin-NFAT signaling cascades in LAD2 cells. G(o) proteins were required for the activation of MAPKs and NF-kappa B in TLR2 stimulated LAD2 cells. Therefore, the genetic depletion of G alpha(o) proteins also led to the reduction of the release of IL-8 in LAD2 cells. Taken together, the data presented here suggest that TLR2 activation in human mast cells promotes the release of inflammatory mediators via distinct signaling pathways that partially depend on the action of G(o) proteins.

Toll-like receptors (TLRs) expressed on mast cells are essential for effective host defense against a wide variety of pathogens. Previous studies have demonstrated that both TLR2 agonists Pam3CSK4 and PGN stimulated IL-8 release in human mast cells. To determine the molecular basis for this phenomenon, we utilized human mast cell line LAD2 cells. We found that only the release of IL-8 stimulated by Pam3CSK4 was TLR2-mediated, which was confirmed by specific TLR2 shRNA. Heterotrimeric G proteins have been previously implicated in TLR signaling in macrophages and monocytes. In the current study, we showed that PamCSK4 induced the activation of MAPKs, NF-kappa B, PI3K-Akt and Ca2+-calcineurin-NFAT signaling cascades in LAD2 cells. G(o) proteins were required for the activation of MAPKs and NF-kappa B in TLR2 stimulated LAD2 cells. Therefore, the genetic depletion of G alpha(o) proteins also led to the reduction of the release of IL-8 in LAD2 cells. Taken together, the data presented here suggest that TLR2 activation in human mast cells promotes the release of inflammatory mediators via distinct signaling pathways that partially depend on the action of G(o) proteins.