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Cigarette smoke extract (CSE) induces apoptosis and inflammation, but the mechanism is unknown. Arginine methyltransferase (PRMT6) catalyzes the asymmetric di-methylation of histone H3 arginine 2 (H3R2me2a) to control global level transcription. We hypothesized that PRMT6 mediates CSE induced apoptosis and inflammation through H3R2me2a. The apoptosis after CSE treatment in human umbilical vein endothelial cells (HUVECs) was fully measured with real-time reverse transcription PCR, western blotting and Annexin-V staining. Meanwhile, the inflammation in HUVECs after CSE exposure was detected with real-time reverse transcription PCR, western blotting and ELISA. CSE treatment promoted apoptosis and inflammation in HUVECs, coinciding with the decreased protein abundance of PRMT6. Meanwhile, HUVECs transfected with PRMT6 expressing plasmid inhibited the CSE-induced apoptosis and inflammation. Also, the inhibition of PRMT6 promoted the apoptosis and inflammation in HUVECs induced by CSE. Notably, H3R2me2a was associated with the modulation of PRMT6 in CSE induced apoptosis and inflammation in HUVECs. In conclusion, PRMT6 mediates CSE induced apoptosis and inflammation through H3R2me2a in HUVECs., (Copyright © 2014 Elsevier B.V. All rights reserved.)

During sepsis, the inflammatory response, oxidative stress, and NET release can cause organ damage. Caffeic acid reversed NET release and delayed LPS-stimulated neutrophil apoptosis. Caffeic acid treatment had protective effects on lung and liver injury in a mouse model of sepsis. The mechanism of these protective effects might be related to inhibition of the 5-LOX/LTB4 pathway. [Display omitted] • Caffeic acid protects against lung and liver injury induced by sepsis. • Caffeic acid reduces inflammatory and oxidative responses in the lungs and livers of septic mice. • Caffeic acid inhibits neutrophil inflammatory activation and NET release in vitro. • Caffeic acid reverses delayed apoptosis in the LPS-stimulated human neutrophils. • Caffeic acid modulates activation of neutrophils and attenuates sepsis-induced organ injury by inhibiting 5-LOX/LTB4 pathway. Sepsis is a critical systemic inflammatory syndrome which usually leads to multiple organ dysfunction. Caffeic acid (CA), a phenolic compound derived from various plants, has been proved to be essential in neuroprotection, but its role in septic organ damage is unclear. This research aimed to investigate whether CA protects against organ injury in a mouse model of cecal ligation and puncture (CLP). CA (30 mg/kg) or vehicle was administered by intraperitoneal injection immediately after CLP. The samples of blood, lungs, and livers were collected 24 h later. Organ injury was assessed by histopathological examination (HE staining), neutrophil infiltration (myeloperoxidase fluorescence), oxidative stress levels (MDA, SOD, HO-1), and inflammatory cytokines (TNF-α, IL-1β, and IL-6) release in lung and liver tissues. Neutrophil extracellular trap (NET) formation was analyzed by immunofluorescence. In vitro experiments were performed to investigate the potential mechanisms of CA using small interfering RNA (siRNA) techniques in neutrophils, and the effect of CA on neutrophil apoptosis was analyzed by flow cytometry. Results showed that CA treatment improved the 7-day survival rate and attenuated the histopathological injury in the lung and liver of CLP mice. CA significantly reduced neutrophil infiltration in the lungs and livers of CLP mice. TNF-α, IL-1β, IL-6 and LTB4 were reduced in serum, lung, and liver of CA-treated CLP mice, and phosphorylation of MAPK (p38, ERK, JNK) and p65 NF-κB was inhibited in lungs and livers. CA treatment further increased HO-1 levels and enhanced superoxide dismutase (SOD) activity, but reduced malondialdehyde (MDA) levels and NET formation. Similarly, in vitro experiments showed that CA treatment and 5-LOX siRNA interference inhibited inflammatory activation and NET release in neutrophils, suppressed MAPK and NF-κB phosphorylation in LPS-treated neutrophils, and decreased LTB4 and cfDNA levels. Flow cytometric analysis revealed that CA treatment reversed LPS-mediated delayed apoptosis in human neutrophils, and Western blot also indicated that CA treatment inhibited Bcl-2 expression but increased Bax expression. CA treatment did not induce further changes in neutrophil apoptosis, inflammatory activation, and NET release when 5-LOX was knocked down by siRNA interference. CA has a protective effect on lung and liver injury in a murine model of sepsis, which may be related to inhibition of the 5-LOX/LTB4 pathway. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cigarette smoke can significantly induced inflammation and apoptosis in vivo and vitro. • Our results proved the protective effects of TAX against cigarette smoke induced inflammation and apoptosis in COPD. Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality worldwide and is characterized by chronic airway inflammation and lung parenchymal cell apoptosis. Cigarette smoke is the major risk factor for the occurrence and development of COPD. Taxifolin (TAX) showed promising pharmacological effects in the management of inflammation, oxidative stress, and apoptosis. In the present study, our results demonstrated that TAX significantly alleviated cigarette smoke-induced inflammation and apoptosis both in vivo and in vitro. TAX notably lowered the elevated total cell count in mouse BALF compared with that in the COPD group. The cigarette smoke-induced emphysematous changes were remarkably reversed by TAX. In addition, treatment with TAX suppressed the elevated mRNA and protein levels of IL-1β, IL-6 and TNF-α in COPD mouse lung tissue and cigarette smoke extract (CSE)-treated human bronchial epithelial cells (HBECs). Additionally, TAX significantly decreased the ratios of p-iκB to iκB and p-p65 to p65 compared with the COPD group and CSE-treated HBECs. Moreover, the results of the TUNEL assay and flow cytometry also demonstrated the anti-apoptotic effect of TAX in mouse lung tissue and HBECs. Furthermore, the elevated Bax and CCP3 levels and decreased Bcl-2 levels induced by cigarette smoke were significantly reversed by TAX treatment in vivo and in vitro. Our results highlight the ameliorating effects of TAX against cigarette smoke-induced inflammation and apoptosis in the pathogenesis of COPD. [ABSTRACT FROM AUTHOR]