6-Hydroxy-5,7-dimethoxy-flavone suppresses the neutrophil respiratory burst via selective PDE4 inhibition to ameliorate acute lung injury

Tsai, Yung Fong; Chu, Tzu Chi; Chang, Wen‐Yi; Wu, Yang Chang; Chang, Fang Rong; Yang, Shung Haur; Wu, Tung Ying; Hsu, Yu Ming; Chen, Chun Yu; Chang, Shwu Fen; Hwang, Tsong‐Long

doi:10.1016/j.freeradbiomed.2017.03.002

Cited by 29 publications

(26 citation statements)

References 54 publications

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“…Blood samples were donated only from healthy young people (20-30 years of age). Buffy coats containing neutrophils were obtained from donated whole blood using a dextran sedimentation assay, as described in [20]. The buffy coats were then collected using differential centrifugation in a Ficoll Hypaque.…”

Section: Human Neutrophil Preparationmentioning

confidence: 99%

“…The changes in absorbance were analyzed continuously at 550 nm by a spectrophotometer. DHR123 dye was used to probe reactive oxygen species [20].…”

Section: Determination Of Superoxide Anion and Reactive Oxygen Speciementioning

confidence: 99%

“…Neutrophils were primed using cytochalasin B for 3 min prior to cell activation. Data are presented as the percentages of the levels obtained from the control group [20].…”

Section: Measurement Of Elastase Releasementioning

confidence: 99%

“…In dipenyl picryl hydrazyl (DPPH) scavenging assays, DMSO or GMC were added to the ethanol buffer of DPPH (0.1 mM). The change in absorbance was measured at 30°C at 517 nm, and the data were compared with the data obtained from the control [20].…”

Section: Assays Of the Scavenging Effects Of Superoxide Anions And DImentioning

confidence: 99%

“…The separated proteins were blotted onto transfer membrane and treated with primary antibodies The intensity of the blotted proteins was determined using a chemiluminescence substrate (Amersham Biosciences, Piscataway, NJ) on a UVP Biospectrum imager (UVP, Upland, CA) [13,20].…”

Section: Western Immunoblotting Analysismentioning

confidence: 99%

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Garcinia Multiflora Inhibits FPR1-Mediated Neutrophil Activation and Protects Against Acute Lung Injury

Tsai

Yang

Chang

et al. 2018

Cell Physiol Biochem

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Background/Aims: Formyl peptide receptors (FPRs) recognize different endogenous and exogenous molecular stimuli and mediate neutrophil activation. Dysregulation of excessive neutrophil activation and the resulting immune responses can induce acute lung injury (ALI) in the host. Accordingly, one promising approach to the treatment of neutrophil-dominated inflammatory diseases involves therapeutic FPR1 inhibition. Methods: We extracted a potent FPR1 antagonist from Garcinia multiflora Champ. (GMC). The inhibitory effects of GMC on superoxide anion release and elastase degranulation from activated human neutrophils were determined with spectrophotometric analysis. Reactive oxygen species (ROS) production and the FPR1 binding ability of neutrophils were assayed by flow cytometry. Signaling transduction mediated by GMC in response to chemoattractants was assessed with a calcium influx assay and western blotting. A lipopolysaccharide (LPS)-induced ALI mouse model was used to determine the therapeutic effects of GMC in vivo. Results: GMC significantly reduced superoxide anion release, the reactive oxidants derived therefrom, and elastase degranulation mediated through selective, competitive FPR1 blocking in N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLF)-stimulated human neutrophils. In cell-free systems, GMC was unable to scavenge superoxide anions or suppress elastase activity. GMC produced a right shift in fMLF-activated concentration-response curves and was confirmed to be a competitive FPR1 antagonist. GMC binds to FPR1 not only in neutrophils, but also FPR1 in neutrophil-like THP-1 and hFPR1-transfected HEK293 cells. Furthermore, the mobilization of calcium and phosphorylation of mitogen-activated protein kinases and Akt, which are involved in FPR1-mediated downstream signaling, was competitively blocked by GMC. In an in vivo study, GMC significantly reduced pulmonary edema, neutrophil infiltration, and alveolar damage in LPS-induced ALI mice. Conclusion: Our findings demonstrate that GMC is a natural competitive FPR1 inhibitor, which makes it a possible anti-inflammatory treatment option for patients critically inflicted with FPR1-mediated neutrophilic lung damage.

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Section: Human Neutrophil Preparationmentioning

confidence: 99%

“…The changes in absorbance were analyzed continuously at 550 nm by a spectrophotometer. DHR123 dye was used to probe reactive oxygen species [20].…”

Section: Determination Of Superoxide Anion and Reactive Oxygen Speciementioning

confidence: 99%

“…Neutrophils were primed using cytochalasin B for 3 min prior to cell activation. Data are presented as the percentages of the levels obtained from the control group [20].…”

Section: Measurement Of Elastase Releasementioning

confidence: 99%

Section: Assays Of the Scavenging Effects Of Superoxide Anions And DImentioning

confidence: 99%

Section: Western Immunoblotting Analysismentioning

confidence: 99%

See 3 more Smart Citations