Cigarette smoke extract upregulates heme oxygenase-1 via PKC/NADPH oxidase/ROS/PDGFR/PI3K/Akt pathway in mouse brain endothelial cells

Abstract

BackgroundIn the brain, the inducible form of heme oxygenase (HO-1) has been recently demonstrated to exacerbate early brain injury produced by intracerebral hemorrhagic stroke which incident rate has been correlated with cigarette smoking previously. Interestingly, cigarette smoke (CS) or chemicals present in CS have been shown to induce HO-1 expression in various cell types, including cerebral endothelial cells. However, the mechanisms underlying CS modulating HO-1 protein expression are not completely understood in the brain vessels.ObjectiveThe aim of the present study was to investigate the mechanisms underlying CS modulating HO-1 protein expression in cerebral endothelial cells.MethodsCultured cerebral endothelial cells (bEnd.3) were used to investigate whether a particulate phase of cigarette smoke extract (PPCSE) regulates HO-1 expression and to investigate the molecular mechanisms involved in HO-1 expression in bEnd.3 cells.ResultsWe demonstrated that PPCSE (30 μg/ml) significantly induced HO-1 protein expression and its enzymatic activity in bEnd.3 cells determined by western blotting and bilirubin formation, respectively. PPCSE-induced HO-1 expression was mediated through phosphatidylcholine phospholipase C (PC-PLC), PKCδ, and PI3K/Akt which were observed by pretreatment with their respective pharmacological inhibitors or transfection with dominant negative mutants of PKCδ and Akt. ROS scavenger (N-acetyl-L-cysteine, NAC) blocked the PPCSE-induced ROS generation and HO-1 expression. Pretreatment with selective inhibitors of PKCδ (rottlerin) and NADPH oxidase [diphenyleneiodonium chloride (DPI) and apocynin (APO)] attenuated the PPCSE-induced NADPH oxidase activity, ROS generation, and HO-1 expression. In addition, we found that PPCSE induced PI3K/Akt activation via NADPH oxidase/ROS-dependent PDGFR phosphorylation.ConclusionsTaken together, these results suggested that PPCSE-induced HO-1 expression is mediated by a PC-PLC/PKCδ/NADPH oxidase-dependent PDGFR/PI3K/Akt pathway in bEnd.3 cells.

Antiinflammatory Effects of Orientin-2″-<i>O</i>-Galactopyranoside on Lipopolysaccharide-Stimulated Microglia

“…It was reported that MAPK, ROS, PKC and NF-κB are involved in the regulation of HO-1 expression under oxidative stress. 48,52,53) However, in the present study, OGA alone did not activate MAPK (p38, JNK, ERK), indicating that activation of MAPKs are not involved at least in OGA induced HO-1 expression in microglia cells. The contradictory results of the regulatory role of MAPK pathways on HO-1 expression were observed under different conditions.…”

Ginkgo biloba extract inhibits oxidized low-density lipoprotein (oxLDL)-induced matrix metalloproteinase activation by the modulation of the lectin-like oxLDL receptor 1-regulated signaling pathway in human umbilical vein endothelial cells

“…32 PKC contains multiple cysteine remains, and those could be oxidized and activated by free radicals. 33 Li et al 17 reported that PKC plays an important role in oxLDL-activated MMP overexpression by modulating LOX-1 function. In our investigation, we hypothesized that GbE exerts its antiatherogenic function by obstructing ROS-mediated PKC activation.…”

Cigarette smoke extract-induced adipogenesis in Graves' orbital fibroblasts is inhibited by quercetin via reduction in oxidative stress

“…Among the isoforms of HO, only HO-1 is induced by xenobiotics and by a variety of agents that cause oxidative stress, such as CSE, hypoxia, and cytokines (Baglole et al 2008, Lee et al 2010, Shih et al 2011. The induction of HO-1 is considered to be part of the generalized protective response to oxidative stress, as an active defense mechanism.…”