Thrombin Induces COX-2 and PGE 2 Expression via PAR1/PKCalpha/MAPK-Dependent NF-kappaB Activation in Human Tracheal Smooth Muscle Cells

• Published in: Mediators of inflammation 2022, Vol.2022, p.4600029
• Main Authors: Yang, Chien-Chung, Hsiao, Li-Der, Shih, Ya-Fang, Hsu, Chih-Kai, Hu, Chia-Yu, Yang, Chuen-Mao
• Format: Article
• Language: English
• Subjects: Cyclooxygenase 2 - genetics; Dinoprostone; Humans; Myocytes, Smooth Muscle; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Protein Kinase C-alpha; Receptor, PAR-1; Thrombin - pharmacology
• ISSN: 1466-1861
• DOI: 10.1155/2022/4600029

The inflammation of the airway and lung could be triggered by upregulation cyclooxygenase (COX)-2 and prostaglandin E (PGE ) induced by various proinflammatory factors. COX-2 induction by thrombin has been shown to play a vital role in various inflammatory diseases. However, in human tracheal smooth muscle cells (HTSMCs), how thrombin enhanced the levels of COX-2/PGE is not completely characterized. Thus, in this study, the levels of COX-2 expression and PGE synthesis induced by thrombin were determined by Western blot, promoter-reporter assay, real-time PCR, and ELISA kit. The various signaling components involved in the thrombin-mediated responses were differentiated by transfection with siRNAs and selective pharmacological inhibitors. The role of NF- B was assessed by a chromatin immunoprecipitation (ChIP) assay, immunofluorescent staining, as well as Western blot. Our results verified that thrombin markedly triggered PGE secretion via COX-2 upregulation which were diminished by the inhibitor of thrombin (PPACK), PAR1 (SCH79797), G protein (GPA2), G protein (GPA2A), PKC (Gö6976), p38 MAPK (SB202190), JNK1/2 (SP600125), MEK1/2 (U0126), or NF- B (helenalin) and transfection with siRNA of PAR1, G , G , PKC , JNK2, p38, p42, or p65. Moreover, thrombin induced PAR1-dependent PKC phosphorylation in HTSMCs. We also observed that thrombin induced p38 MAPK, JNK1/2, and p42/p44 MAPK activation through a PAR1/PKC pathway. Thrombin promoted phosphorylation of NF- B p65, leading to nuclear translocation and binding to the COX-2 promoter element to enhance promoter activity, which was reduced by Gö6976, SP600125, SB202190, or U0126. These findings supported that COX-2/PGE expression triggered by thrombin was engaged in PAR1/G or G /PKC /MAPK-dependent NF- B activation in HTSMCs.