Effective attenuation of acute lung injury in vivo and the formyl peptide-induced neutrophil activation in vitro by CYL-26z through the phosphoinositide 3-kinase gamma pathway.
5-[4-Acridin-9-ylamino]phenyl]-5-methyl-3-methylenedihydrofuran-2-one (CYL-26z) inhibited the polymorphonuclear leukocyte (PMNL) infiltration and protein leakage into the lungs in lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice as determined on the basis of PMNL and protein contents in bronchoalveolar lavage (BAL) fluid and myeloperoxidase (MPO) content in whole lung extracts. CYL-26z also attenuated the formyl-Met-Leu-Phe (fMLP)-induced neutrophil chemotaxis and respiratory burst in vitro (IC(50) 8.4+/-0.9microM and 2.0+/-0.6microM, respectively). CYL-26z had no effect on superoxide anion (O(2)(-)) generation during dihydroxyfumaric acid autoxidation or on the NADPH oxidase activity in two cell-free systems (the arachidonic acid-induced assembly of NADPH oxidase and the preassembled oxidase caused by phorbol ester treatment), whereas it inhibited NaF-induced respiratory burst. Inhibition of respiratory burst by CYL-26z was readily reversible by washing. Only slight, but significant, inhibition of extracellular signal regulated kinase (ERK) phosphorylation and p38 mitogen-activated protein kinase (MAPK) activation in response to fMLP by CYL-26z up to 30microM was obtained. CYL-26z effectively blocked the formation of phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) as determined by immunofluorescence microscopy and flow cytometry assays and the dual phosphorylation of protein kinase B (PKB/Akt) on S473 and T308 residues in fMLP-stimulated neutrophils. The membrane recruitment of p110gamma and Ras, the Ras activation, and the association between p110gamma and Ras were also attenuated by CYL-26z. These results indicate that the blockade of Ras activation by CYL-26z attenuated the downstream phosphoinositide 3-kinase (PI3K) gamma signaling, which is involved in chemoattractant-induced neutrophil chemotaxis and respiratory burst, and may have a beneficial anti-inflammatory effect on ALI.
Kuan
Yu-Hsiang
YH
Department of Education and Research, Taichung Veterans General Hospital, Taichung 407, Taiwan, ROC.
Lin
Ruey-Hseng
RH
Chen
Yeh-Long
YL
Tsao
Lo-Ti
LT
Tzeng
Cherng-Chyi
CC
Wang
Jih-Pyang
JP
D000166:Acridines / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D058534:Class I Phosphatidylinositol 3-Kinases; D005663:Furans / Q000494:pharmacology / Q000627:therapeutic use*; D051379:Mice; D018375:Neutrophil Activation / Q000187:drug effects* / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000188:drug therapy*; D015398:Signal Transduction
D000166:Acridines; D058534:Class I Phosphatidylinositol 3-Kinases; D005663:Furans; D019869:Phosphatidylinositol 3-Kinases; C504217:5-(4-acridin-9-ylamino)phenyl-5-methyl-3-methylenedihydrofuran-2-one; C484760:PIK3CA protein, human