title: ATP mediates NADPH oxidase/ROS generation and COX-2/PGE2 expression in A549 cells: role of P2 receptor-dependent STAT3 activation.
abstract: BACKGROUND
  Up-regulation of cyclooxygenase (COX)-2 and its metabolite prostaglandin E(2) (PGE(2)) are frequently implicated in lung inflammation. Extracellular nucleotides, such as ATP have been shown to act via activation of P2 purinoceptors, leading to COX-2 expression in various inflammatory diseases, such as lung inflammation. However, the mechanisms underlying ATP-induced COX-2 expression and PGE(2) release remain unclear.
  
  
  RESULTS
  Here, we showed that ATPγS induced COX-2 expression in A549 cells revealed by western blot and real-time PCR. Pretreatment with the inhibitors of P2 receptor (PPADS and suramin), PKC (Gö6983, Gö6976, Ro318220, and Rottlerin), ROS (Edaravone), NADPH oxidase [diphenyleneiodonium chloride (DPI) and apocynin], Jak2 (AG490), and STAT3 [cucurbitacin E (CBE)] and transfection with siRNAs of PKCα, PKCι, PKCμ, p47(phox), Jak2, STAT3, and cPLA(2) markedly reduced ATPγS-induced COX-2 expression and PGE(2) production. In addition, pretreatment with the inhibitors of P2 receptor attenuated PKCs translocation from the cytosol to the membrane in response to ATPγS. Moreover, ATPγS-induced ROS generation and p47(phox) translocation was also reduced by pretreatment with the inhibitors of P2 receptor, PKC, and NADPH oxidase. On the other hand, ATPγS stimulated Jak2 and STAT3 activation which were inhibited by pretreatment with PPADS, suramin, Gö6983, Gö6976, Ro318220, GF109203X, Rottlerin, Edaravone, DPI, and apocynin in A549 cells.
  
  
  CONCLUSIONS
  Taken together, these results showed that ATPγS induced COX-2 expression and PGE(2) production via a P2 receptor/PKC/NADPH oxidase/ROS/Jak2/STAT3/cPLA(2) signaling pathway in A549 cells. Increased understanding of signal transduction mechanisms underlying COX-2 gene regulation will create opportunities for the development of anti-inflammation therapeutic strategies.
authors: Department of Physiology and Pharmacology and Health Aging Research Center, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
authors: Shin-Ei
authors: SE
authors: Cheng
authors: I-Ta
authors: IT
authors: Lee
authors: Chih-Chung
authors: CC
authors: Lin
authors: Wan-Ling
authors: WL
authors: Wu
authors: Li-Der
authors: LD
authors: Hsiao
authors: Chuen-Mao
authors: CM
authors: Yang
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D015232:Dinoprostone / Q000096:biosynthesis* / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D008168:Lung / Q000473:pathology; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015533:Transcriptional Activation
chemical_list: D017382:Reactive Oxygen Species; D018048:Receptors, Purinergic P2; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D019255:NADPH Oxidases; D015232:Dinoprostone