EET Displays Anti-Inflammatory Effects in TNF-α–Stimulated Human Bronchi

Abstract

The aim of the present study was to investigate the anti-inflammatory effects of 14,15-epoxyeicosatrienoic acid (EET) on reactivity and Ca(2+) sensitivity in TNF-alpha-stimulated human bronchi. Tension measurements performed on either control, TNF-alpha-, or TNF-alpha + EET-pretreated bronchi revealed that 100 nM 14,15-EET pretreatments significantly reduced the reactivity of TNF-alpha-pretreated tissues to contractile agonists. EET also normalized the relaxing response to isoproterenol in TNF-alpha-treated bronchi. Pretreatment with 100 nM 14,15-EET prevented TNF-alpha-induced IkappaBalpha degradation, as demonstrated by an increase in IkappaBalpha protein levels on Western blot analysis. The anti-inflammatory properties of EET were mediated by the inhibition of IkappaBalpha degradation, suggesting a lower activation of NF-kappaB. The Ca(2+) sensitivity of TNF-alpha-stimulated bronchi was also evaluated on beta-escin-permeabilized preparations. Observed mean responses demonstrated that EET pretreatments abolished Ca(2+) hypersensitivity developed by TNF-alpha-stimulated bronchial explants. Moreover, 14,15-EET significantly reduced PDBu-induced Ca(2+) sensitivity in TNF-alpha-stimulated bronchi. Western blot and RT-PCR analyses revealed that CPI-17 protein and transcript levels were increased in TNF-alpha-treated bronchi, as opposed to being decreased in the presence of 14,15-EET. This eicosanoid also reduced U-46619-induced Ca(2+) sensitivity, which is related to the activation of Rho-kinase pathway. These results were also correlated with an increase in protein staining and transcription level of p116(Rip), a RhoA inhibitory-binding protein. Altogether, these data demonstrate that 14,15-EET is a potent modulator of the hyperreactivity triggered by TNF-alpha in human airway smooth muscle cells.

Lipoxin Generation Is Related to Soluble Epoxide Hydrolase Activity in Severe Asthma

“…Direct exposure to 15-epi-LXA 4 reduced TNF-a-triggered responses by 113.5, 106.3, and 90.1% for MCh, histamine, and U-46619, respectively. For purposes of comparison with data included in our prior publication (28), exposure to 14,15-EET reduced TNFa-induced bronchial contraction to these same agonists by 78.4, 73.4, and 85.2%, respectively ( Figure 7D). …”

“…Surgical specimens were obtained and exposed (48 h) to 15-epi-LXA 4 (100 nM), 14,15-EET (100 nM), or vehicle with TNF-a (10 ng/ml) to increase bronchial reactivity as in (28) Figure 7C). TNF-a increased bronchial contractile responses to the same agents to 0.31 6 0.04 g, 0.45 6 0.07 g, and 0.55 6 0.07 g, which represent significant increases in the active tension of 63%, 61%, and 62%, respectively, compared with media alone ( Figure 7C).…”

Application of Fullerenes in Nanomedicine: An Update

“…Certain EETs stabilize human lung MCs through the inhibition of FcεRI-mediator release and upregulate the CYP1B1 gene in these cells ( Figure 4). Thought to be produced by lung epithelial and endothelial cells, the EETs have been shown to relax histamine-precontracted guinea pig and human bronchi [35,36] . Furthermore, they can inhibit the upregulation of VCAM-1, E-selectin, and ICAM-1, thus, potentially limiting cellular infiltration of the lung [37] .…”

Augmented PDBu-mediated contraction of bronchial smooth muscle of mice with antigen-induced airway hyperresponsiveness

“…TNF- is released in allergic responses from both mast cells and macrophages via IgE-dependent mechanisms, and elevated levels have been demonstrated in the bronchoalveolar fluid (BALF) of asthmatic subjects undergoing allergen challenge (Thomas, 2001). Morin et al (2008) demonstrated that TNF- increased the CPI-17 expression level in human bronchial tissues. Previous studies revealed that CPI-17 expression of bronchial smooth muscle (Sakai et al, 2005) were increased by repeatedly antigen-challenge in rat.…”