Application of a phenotypic drug discovery strategy to identify biological and chemical starting points for inhibition of TSLP production in lung epithelial cells.

Thymic stromal lymphopoietin (TSLP) is a cytokine released by human lung epithelium in response to external insult. Considered as a master switch in T helper 2 lymphocyte (Th2) mediated responses, TSLP is believed to play a key role in allergic diseases including asthma. The aim of this study was to use a phenotypic approach to identify new biological and chemical starting points for inhibition of TSLP production in human bronchial epithelial cells (NHBE), with the objective of reducing Th2-mediated airway inflammation.

Combined anti CXC receptors 1 and 2 therapy is a promising anti-inflammatory treatment for respiratory diseases by reducing neutrophil migration and activation.

Neutrophil infiltration and activation in the lung are important pathophysiological features in COPD, severe asthma and bronchiectasis mostly mediated by CXCL8 and CXCL1 via CXCR1 and CXCR2. No thorough study to date has been performed to compare the anti-inflammatory effect profile of dual CXCR1/2 vs. selective CXCR2 antagonists in relevant human neutrophil assays and pulmonary inflammation models.

Estradiol and mTORC2 cooperate to enhance prostaglandin biosynthesis and tumorigenesis in TSC2-deficient LAM cells.

Lymphangioleiomyomatosis (LAM) is a progressive neoplastic disorder that leads to lung destruction and respiratory failure primarily in women. LAM is typically caused by tuberous sclerosis complex 2 (TSC2) mutations resulting in mTORC1 activation in proliferative smooth muscle-like cells in the lung. The female predominance of LAM suggests that estradiol contributes to disease development.

Exhaled breath condensate eicosanoid levels associate with asthma and its severity.

Background: The relationship between anti-inflammatory lipoxins and proinflammatory leukotrienes might be important in the pathobiology and severity of asthma.

Objective: We sought to investigate whether exhaled breath condensate (EBC) lipoxin and leukotriene measurements can noninvasively characterize the asthmatic diathesis and its severity.

Methods: We measured lipoxin A4 (LXA4) and leukotriene B4 (LTB4) levels in EBC collected from patients with asthma of different severities and from healthy control subjects.

Lack of activity of 15-epi-lipoxin A₄ on FPR2/ALX and CysLT1 receptors in interleukin-8-driven human neutrophil function.

Neutrophil recruitment and survival are important control points in the development and resolution of inflammatory processes. 15-epi-lipoxin (LX)A interaction with formyl peptide receptor 2 (FPR2)/ALX receptor is suggested to enhance anti-inflammatory neutrophil functions and mediate resolution of airway inflammation. However, it has been reported that 15-epi-LXA₄ analogues can also bind to cysteinyl leukotriene receptor 1 (CysLT1) and that the CysLT1 antagonist MK-571 binds to FPR2/ALX, so cross-reactivity between FPR2/ALX and CysLT1 ligands cannot be discarded.

Lovastatin decreases acute mucosal inflammation via 15-epi-lipoxin A4.

The widespread use of statins for hypercholesterolemia has uncovered pleiotropic anti-inflammatory properties that were unexpected based on the drugs' original design; yet, mechanisms for these protective actions remain uncertain. In this study lovastatin triggered biosynthesis of the anti-inflammatory and pro-resolving mediator 15-epi-lipoxin A(4) (15-epi-LXA(4)). During interactions between human neutrophils and airway epithelial cells, the statin-induced increase in 15-epi-LXA(4) was associated with increased 14,15-epoxyeicosatrienoic acid (14,15-EET) generation.

Increased susceptibility to exacerbated liver injury in hypercholesterolemic ApoE-deficient mice: potential involvement of oxysterols.

The contribution of metabolic factors to the severity of liver disease is not completely understood. In this study, apolipoprotein E-deficient (ApoE-/-) mice were evaluated to define potential effects of hypercholesterolemia on the severity of carbon tetrachloride (CCl4)-induced liver injury. Under baseline conditions, hypercholesterolemic ApoE-/- mice showed increased hepatic oxidative stress (SOD activity/4-hydroxy-2-nonenal immunostaining) and higher hepatic TGF-beta1, MCP-1, and TIMP-1 expression than wild-type control mice.

Regulatory effects of arachidonate 5-lipoxygenase on hepatic microsomal TG transfer protein activity and VLDL-triglyceride and apoB secretion in obese mice.

As 5-lipoxygenase (5-LO) is an emerging target in obesity and insulin resistance, we have investigated whether this arachidonate pathway is also implicated in the progression of obesity-related fatty liver disease. Our results show that 5-LO activity and 5-LO-derived product levels are significantly elevated in the liver of obese ob/ob mice with respect to wild-type controls. Treatment of ob/ob mice with a selective 5-LO inhibitor exerted a remarkable protection from hepatic steatosis as revealed by decreased oil red-O staining and reduced hepatic triglyceride (TG) concentrations.

Airway lipoxin A4 generation and lipoxin A4 receptor expression are decreased in severe asthma.

Rationale: Airway inflammation is common in severe asthma despite antiinflammatory therapy with corticosteroids. Lipoxin A(4) (LXA(4)) is an arachidonic acid-derived mediator that serves as an agonist for resolution of inflammation.

Objectives: Airway levels of LXA(4), as well as the expression of lipoxin biosynthetic genes and receptors, in severe asthma.

Uncontrolled airway inflammation in lung disease represents a defect in counter-regulatory signaling.

Counter-regulatory lipid mediators are generated during airway inflammation to promote resolution. Defects in the production of these lipid mediators have now been associated with several diseases of persistent airway inflammation. Lipoxins are the lead members of this class of anti-inflammatory and proresolving chemical mediators.

Comparative protection against liver inflammation and fibrosis by a selective cyclooxygenase-2 inhibitor and a nonredox-type 5-lipoxygenase inhibitor.

In this study, we examined the relative contribution of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO), two major proinflammatory pathways up-regulated in liver disease, to the progression of hepatic inflammation and fibrosis. Separate administration of 4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (SC-236), a selective COX-2 inhibitor, and CJ-13,610, a 5-LO inhibitor, to carbon tetrachloride-treated mice significantly reduced fibrosis as revealed by the analysis of Sirius Red-stained liver sections without affecting necroinflammation. Conversely, combined administration of SC-236 and 4-[3-[4-(2-methylimidazol-1-yl)-phenylthio]]phenyl-3,4,5,6-tetrahydro-2H-pyran-4-carboxamide (CJ-13,610) reduced both necroinflammation and fibrosis.

Docosahexaenoic acid (DHA) blunts liver injury by conversion to protective lipid mediators: protectin D1 and 17S-hydroxy-DHA.

Docosahexaenoic acid (DHA) is a omega-3 essential fatty acid that reduces the incidence and severity of a number of diseases. Recently, a novel series of DHA-derived lipid mediators with potent protective actions has been identified. In this study we demonstrate that dietary amplification of these DHA-derived products protects the liver from necroinflammatory injury.

Gene expression profiling of renal dysfunction in rats with experimental cirrhosis.

Background/aims: Renal dysfunction is a frequent complication in advanced cirrhosis. The mechanisms underlying this complication have classically been addressed through conventional methods of study of candidate genes, but never on a genome-wide scale. In this investigation, we used microarrays to monitor global gene expression changes in the kidney of cirrhotic rats.

Inhibition of 5-lipoxygenase-activating protein abrogates experimental liver injury: role of Kupffer cells.

Activation of Kupffer cells is a prominent feature of necro-inflammatory liver injury. We have recently demonstrated that 5-lipoxygenase (5-LO) and its accessory protein, 5-LO-activating protein (FLAP), are essential for the survival of Kupffer cells in culture, as their inhibition drives these liver resident macrophages to programmed cell death. In the current study, we explored whether the potent FLAP inhibitor, Bay-X-1005, reduces the number of Kupffer cells in vivo and whether this pharmacological intervention protects the liver from carbon tetrachloride (CCl(4))-induced damage.

Liver: the formation and actions of aspirin-triggered lipoxins.

Eicosanoids play a key role in the initiation, progression and resolution of the inflammatory response. Although most current anti-inflammatory strategies are focused on the pharmacological inhibition of pro-inflammatory eicosanoids, such as prostaglandins and leukotrienes, mounting evidence indicates the existence of potent endogenous eicosanoids able to control inflammation and orchestrate its resolution. The first eicosanoids recognized as anti-inflammatory compounds generated by our own organism were the lipoxins (LXs).

The selective cyclooxygenase-2 inhibitor SC-236 reduces liver fibrosis by mechanisms involving non-parenchymal cell apoptosis and PPARgamma activation.

The importance of inflammation in initiating the sequence of events that lead to liver fibrosis is increasingly recognized. In this study, we tested the effects of SC-236, a selective cyclooxygenase (COX)-2 inhibitor, in rats with carbon tetrachloride (CCl4)-induced liver fibrosis. Livers from CCl4-treated rats showed increased COX-2 expression and 15-deoxy-prostaglandin (PG)J2 (15d-PGJ2) formation, as well as decreased peroxisome proliferator-activated receptor (PPAR)gamma expression.

The selective cyclooxygenase-2 inhibitor celecoxib modulates the formation of vasoconstrictor eicosanoids and activates PPARgamma. Influence of albumin.

Background/aims: Selective cyclooxygenase (COX)-2 inhibitors do not adversely affect renal function in experimental cirrhosis. In the current study, we investigated the molecular mechanisms underlying the effects of the selective COX-2 inhibitor, celecoxib, and assessed the influence of albumin on its actions.

Methods: Rat mesangial cells (RMC) were incubated with celecoxib in the absence or presence of albumin, and levels of selected vasoconstrictor eicosanoids, renin release and alpha-smooth muscle actin (alpha-SMA) expression were determined.

Inhibition of 5-lipoxygenase induces cell growth arrest and apoptosis in rat Kupffer cells: implications for liver fibrosis.

The existence of an increased number of Kupffer cells is recognized as critical in the initiation of the inflammatory cascade leading to liver fibrosis. Because 5-lipoxygenase (5-LO) is a key regulator of cell growth and survival, in the current investigation we assessed whether inhibition of the 5-LO pathway would reduce the excessive number of Kupffer cells and attenuate inflammation and fibrosis in experimental liver disease. Kupffer cells were the only liver cell type endowed with a metabolically active 5-LO pathway (i.

Aspirin (ASA) regulates 5-lipoxygenase activity and peroxisome proliferator-activated receptor alpha-mediated CINC-1 release in rat liver cells: novel actions of lipoxin A4 (LXA4) and ASA-triggered 15-epi-LXA4.

The mechanism of action of aspirin (ASA) is related to cyclooxygenase (COX) inhibition, but additional actions cannot be excluded for their antiinflammatory properties and antithrombotic activity. In the current investigation, we examined the effects of ASA on COX and 5-lipoxygenase (5-LO) pathways and its impact on peroxisome proliferator-activated receptor alpha (PPARalpha) and cytokine-induced neutrophil chemoattractant-1 (CINC-1) levels in rat liver cells. In Kupffer cells, the liver resident macrophages, ASA switched eicosanoid biosynthesis from prostaglandin E2 (PGE2) to leukotriene B4 (LTB4) and 15-epi-lipoxin A4 (15-epi-LXA4) formation.

Cyclooxygenase-1 derived prostaglandins are involved in the maintenance of renal function in rats with cirrhosis and ascites.

1. The maintenance of renal function in decompensated cirrhosis is highly dependent on prostaglandins (PGs). Since PG synthesis is mediated by cyclooxygenase-1 and -2 (COX-1 and COX-2), the present study was designed to examine which COX isoform is involved in this phenomenon.

Endogenous cannabinoids: a new system involved in the homeostasis of arterial pressure in experimental cirrhosis in the rat.

Background & Aims: Recent studies have described the existence of endogenous cannabinoids with vasodilator activity because of their interaction with peripheral CB1 receptors, anandamide being the most extensively investigated. The study investigated whether endogenous cannabinoids are involved in the pathogenesis of the cardiovascular disturbances in experimental cirrhosis.

Methods: Arterial pressure, cardiac output, and total peripheral resistance were measured before and after the administration of a cannabinoid CB1 receptor antagonist to cirrhotic rats with ascites and to control rats.