Montelukast prevents microparticle-induced inflammatory and functional alterations in human bronchial smooth muscle cells

Extracellular acidification attenuates bronchial contraction via an autocrine activation of EP2 receptor: Its diminishment in murine experimental asthma

PURPOSE

Extracellular acidification is a major component of tissue inflammation, including airway inflammation in asthmatics. However, its physiological/pathophysiological significance in bronchial function is not fully understood. Currently, the functional role of extracellular acidification on bronchial contraction was explored.

METHODS

Left main bronchi were isolated from male BALB/c mice. Epithelium-removed tissues were exposed to acidic pH under submaximal contraction induced by 10-5 M acetylcholine in the presence or absence of a COX inhibitor indomethacin (10-6 M). Effects of AH6809 (10-6 M, an EP2 receptor antagonist), BW A868C (10-7 M, a DP receptor antagonist) and CAY10441 (3×10-6 M, an IP receptor antagonist) on the acidification-induced change in tension were determined. The release of prostaglandin E2 (PGE2) from epithelium-denuded tissues in response to acidic pH was assessed using an ELISA.

RESULTS

In the bronchi stimulated with acetylcholine, change in the extracellular pH from 7.4 to 6.8 caused a transient augmentation of contraction followed by a sustained relaxing response. The latter inhibitory response was abolished by indomethacin and AH6809 but not by BW A868C or CAY10441. Both indomethacin and AH6809 significantly increased potency and efficacy of acetylcholine at pH 6.8. Stimulation with low pH caused an increase in PGE2 release from epithelium-denuded bronchi. Interestingly, the acidic pH-induced bronchial relaxation was significantly reduced in a murine asthma model that had a bronchial hyperresponsiveness to acetylcholine.

CONCLUSION

Taken together, extracellular acidification could inhibit the bronchial contraction via autocrine activation of EP2 receptors. The diminished acidic pH-mediated inhibition of bronchial tone may contribute to excessive bronchoconstriction in inflamed airways such as asthma.

Montelukast induces beneficial behavioral outcomes and reduces inflammation in male and female rats

Background

Accumulative data links inflammation and immune dysregulation to the pathophysiology of mental disorders; little is known regarding leukotrienes’ (LTs) involvement in this process. Circumstantial evidence suggests that treatment with leukotriene modifying agents (LTMAs) such as montelukast (MTK) may induce adverse neuropsychiatric events. Further methodic evaluation is warranted.

Objective

This study aims to examine behavioral effects, as well as inflammatory mediator levels of chronic MTK treatment in male and female rats.

Methods

Depression-like phenotypes were induced by exposing male and female rats to a chronic unpredictable mild stress (CUMS) protocol for four weeks. Thereafter, rats were treated (intraperitoneally) once daily, for two weeks, with either vehicle (dimethyl sulfoxide 0.2 ml/rat) or 20 mg/kg MTK. Following treatment protocols, behavioral tests were conducted and brain regions were evaluated for inflammatory mediators including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and prostaglandin (PG) E2.

Results

Overall, MTK did not invoke negative behavioral phenotypes (except for an aggression-inducing effect in males). Numerous positive behavioral outcomes were observed, including reduction in aggressive behavior in females and reduced manic/hyperactive-like behavior and increased sucrose consumption (suggestive of antidepressant-like effect) in males. Furthermore, in control males, MTK increased IL-6 levels in the hypothalamus and TNF-α in the frontal cortex, while in control females it generated a robust anti-inflammatory effect. In females that were subjected to CUMS, MTK caused a prominent reduction in TNF-α and IL-6 in brain regions, whereas in CUMS-subjected males its effects were inconsistent.

Conclusion

Contrary to prior postulations, MTK may be associated with select beneficial behavioral outcomes. Additionally, MTK differentially affects male vs. female rats in respect to brain inflammatory mediators, plausibly explaining the dissimilar behavioral phenotypes of sexes under MTK treatment.

Inflammatory modulation of the response of bronchial epithelial cells to lipopolysaccharide with pretreatment by montelukast

Montelukast, a leukotriene receptor antagonist, is the most prescribed nonsteroidal anti-inflammatory drug used as an add-on therapy for asthma. Besides its effect on blocking leukotriene action, montelukast has been proposed to have secondary anti-inflammatory properties. This study aimed to investigate the modulatory effect of montelukast on the expression of major genes involved in airway inflammation (TNF, IL6) and remodeling (MMP9, TGFB1) in response to lipopolysaccharide (LPS) in vitro. The expression of selected genes was measured by quantitative real-time polymerase chain reaction 0h and 24h after LPS stimulation in cells pretreated with montelukast. Montelukast was found to significantly attenuate increased TNF and IL6 gene expression, to have a mild effect on MMP9 and have no effect on TGFB1 expression upon stimulation with LPS. The results of our study indicate that patients on montelukast therapy would have an adequate response to acute microorganism-induced inflammation, so additional anti-inflammatory effects of montelukast should be better exploited.

Levocetirizine and montelukast in the COVID-19 treatment paradigm

Levocetirizine, a third-generation antihistamine, and montelukast, a leukotriene receptor antagonist, exhibit remarkable synergistic anti-inflammatory activity across a spectrum of signaling proteins, cell adhesion molecules, and leukocytes. By targeting cellular protein activity, they are uniquely positioned to treat the symptoms of COVID-19. Clinical data to date with an associated six-month follow-up, suggests the combination therapy may prevent the progression of the disease from mild to moderate to severe, as well as prevent/treat many of the aspects of ‘Long COVID,’ thereby cost effectively reducing both morbidity and mortality. To investigate patient outcomes, 53 consecutive COVID-19 test (+) cases (ages 3–90) from a well-established, single-center practice in Boston, Massachusetts, between March – November 2020, were treated with levocetirizine and montelukast in addition to then existing protocols [2]. The data set was retrospectively reviewed. Thirty-four cases were considered mild (64%), 17 moderate (32%), and 2 (4%) severe. Several patients presented with significant comorbidities (obesity: n = 22, 41%; diabetes: n = 10, 19%; hypertension: n = 24, 45%). Among the cohort there were no exclusions, no intubations, and no deaths. The pilot study in Massachusetts encompassed the first COVID-19 wave which peaked on April 23, 2020 as well as the ascending portion of the second wave in the fall. During this period the average weekly COVID-19 case mortality rate (confirmed deaths/confirmed cases) varied considerably between 1 and 7.5% [37]. FDA has approved a multicenter, randomized, placebo-controlled, Phase 2 clinical trial design, replete with electronic diaries and laboratory metrics to explore scientific questions not addressed herein.

Montelukast promotes mitochondrial biogenesis via CREB/PGC-1α in human bronchial epithelial cells

Bronchial epithelial mitochondrial dysfunction including impaired mitochondrial biogenesis has been linked with the initiation and development of bronchial asthma. Montelukast, a robust antagonist of cysteinyl leukotriene receptors, has been widely applied for the therapies of bronchial asthma. However, the effects of montelukast in airway epithelial mitochondrial dysfunction are less reported. In the present study, we report that montelukast treatment in human bronchial epithelial cells of Beas-2b increased the expressions of PGC-1α, NRF-1 and TFAM. As expected, montelukast promoted mitochondrial biogenesis in Beas-2b cells through increasing mitochondrial mass, mtDNA/nDNA and the expression of cytochrome B. Importantly, we found that montelukast caused a functional gain in mitochondria of Beas-2b cells. Mechanistically, we found that montelukast treatment increased intracellular cAMP levels and activation of CREB. Blockage of CREB with H89 abolished montelukast-induced expression of PGC-1α. These findings report a novel pharmacological function of montelukast in stimulating mitochondrial biogenesis in Beas-2b cells, mediating by the CREB/PGC-1α pathway.

Microvesicles as new therapeutic targets for the treatment of the acute respiratory distress syndrome (ARDS)

Introduction: Acute respiratory distress syndrome (ARDS) is a heterogeneous and multifactorial disease; it is a common and devastating condition that has a high mortality. Treatment is limited to supportive measures hence novel pharmacological approaches are necessary. We propose a new direction in ARDS research; this means moving away from thinking about individual inflammatory mediators and instead investigating how packaged information is transmitted between cells. Microvesicles (MVs) represent a novel vehicle for inter-cellular communication with an emerging role in ARDS pathophysiology.Areas covered: This review examines current approaches to ARDS and emerging MV research. We describe advances in our understanding of microvesicles and focus on their pro-inflammatory roles in airway and endothelial signaling. We also offer reasons for why MVs are attractive therapeutic targets.Expert opinion: MVs have a key role in ARDS pathophysiology. Preclinical studies must move away from simple models toward more realistic scenarios while clinical studies must embrace patient heterogeneity. Microvesicles have the potential to aid identification of patients who may benefit from particular treatments and act as biomarkers of cellular status and disease progression. Understanding microvesicle cargoes and their cellular interactions will undoubtedly uncover new targets for ARDS.

Exosomes: An emerging factor in atherosclerosis

Atherosclerosis is the main reason for morbidity and death caused by cardiovascular disease which leads to approximately 20% of total death around the world. Exosomes secreted by the cells is a kind of extracellular vesicles with lipid bilayer structure, containing a variety of cell specific lipid, nucleic acid and protein, involved in intercellular communication, plays an important role in different physiological and pathological process. In recent years, with the deepening of research, the role of exosomes in cardiovascular diseases has received extensive attention. This review summarizes the roles of exosomes and exosome-derived from microRNAs, proteins and DNA as biomarkers in the development of atherosclerosis, and explores the mechanism of exosome-mediated intercellular crosstalk in atherosclerosis, providing potential roles for diagnosis and treatment.

Zafirlukast Is a Dual Modulator of Human Soluble Epoxide Hydrolase and Peroxisome Proliferator-Activated Receptor γ

Cysteinyl leukotriene receptor 1 antagonists (CysLT1RA) are frequently used as add-on medication for the treatment of asthma. Recently, these compounds have shown protective effects in cardiovascular diseases. This prompted us to investigate their influence on soluble epoxide hydrolase (sEH) and peroxisome proliferator activated receptor (PPAR) activities, two targets known to play an important role in CVD and the metabolic syndrome. Montelukast, pranlukast and zafirlukast inhibited human sEH with IC₅₀ values of 1.9, 14.1, and 0.8 μM, respectively. In contrast, only montelukast and zafirlukast activated PPARγ in the reporter gene assay with EC₅₀ values of 1.17 μM (21.9% max. activation) and 2.49 μM (148% max. activation), respectively. PPARα and δ were not affected by any of the compounds. The activation of PPARγ was further investigated in 3T3-L1 adipocytes. Analysis of lipid accumulation, mRNA and protein expression of target genes as well as PPARγ phosphorylation revealed that montelukast was not able to induce adipocyte differentiation. In contrast, zafirlukast triggered moderate lipid accumulation compared to rosiglitazone and upregulated PPARγ target genes. In addition, we found that montelukast and zafirlukast display antagonistic activities concerning recruitment of the PPARγ cofactor CBP upon ligand binding suggesting that both compounds act as PPARγ modulators. In addition, zafirlukast impaired the TNFα triggered phosphorylation of PPARγ2 on serine 273. Thus, zafirlukast is a novel dual sEH/PPARγ modulator representing an excellent starting point for the further development of this compound class.

Matrix metalloproteinase inhibitors prevent the release and proteolytic activity of monocyte/macrophage-derived microparticles

BACKGROUND

The role of monocyte/macrophage-derived microparticles (MPs) in the pathophysiology of cancer and chronic inflammatory diseases has been reported; nevertheless, the mechanism underlying microparticles release is currently unclear. The aim of the current study was to investigate whether matrix metalloproteinase (MMP) inhibitors could prevent MP shedding from stimulated human monocyte/macrophage.

METHODS

Microparticles were obtained by isolated peripheral blood mononuclear cells after stimulation with the calcium ionophore, A23187. MP shedding, intracellular calcium concentration, analysis of RhoA expression, and proteolytic activities of isolated MPs were assessed in the absence or presence of MMP inhibitors.

RESULTS

We demonstrated that MMP inhibitors remarkably prevented MP shedding in a concentration-dependent manner with IC₅₀ values in the nano- to micromolar range. Such an effect was related to their ability to reduce the intracellular Ca²⁺ levels induced by the calcium ionophore and the consequent translocation of RhoA from cytosol to membrane. Furthermore, MMP inhibitors could inhibit the proteolytic activity of cell-derived MPs.

CONCLUSIONS

The current study provide evidence that MMP inhibitors can prevent MPs shedding from stimulated human monocyte/macrophage and the proteolytic activity of released MPs. Finally, the most active compound tested might represent the lead compound of a new class of molecules with therapeutic potential in cancer and chronic inflammatory diseases.

Cell-derived microparticles and the lung

Cell-derived microparticles are small (0.1-1 μm) vesicles shed by most eukaryotic cells upon activation or during apoptosis. Microparticles carry on their surface, and enclose within their cytoplasm, molecules derived from the parental cell, including proteins, DNA, RNA, microRNA and phospholipids. Microparticles are now considered functional units that represent a disseminated storage pool of bioactive effectors and participate both in the maintenance of homeostasis and in the pathogenesis of diseases. The mechanisms involved in microparticle generation include intracellular calcium mobilisation, cytoskeleton rearrangement, kinase phosphorylation and activation of the nuclear factor-κB. The role of microparticles in blood coagulation and inflammation, including airway inflammation, is well established in in vitro and animal models. The role of microparticles in human pulmonary diseases, both as pathogenic determinants and biomarkers, is being actively investigated. Microparticles of endothelial origin, suggestive of apoptosis, have been demonstrated in the peripheral blood of patients with emphysema, lending support to the hypothesis that endothelial dysfunction and apoptosis are involved in the pathogenesis of the disease and represent a link with cardiovascular comorbidities. Microparticles also have potential roles in patients with asthma, diffuse parenchymal lung disease, thromboembolism, lung cancer and pulmonary arterial hypertension.

Macrophage Foam Cell-Derived Extracellular Vesicles Promote Vascular Smooth Muscle Cell Migration and Adhesion

Background

A new mechanism for intercellular communication has recently emerged that involves intercellular transfer of extracellular vesicles (EVs). Several studies have indicated that EVs may play a potential role in cell‐to‐cell communication between macrophage foam cells and vascular smooth muscle cells (VSMCs) in atherosclerotic lesion.

Methods and Results

This study involved the comparison of circulating EVs from atherosclerotic patients and control participants. The results showed that the circulation of the patients contained more leukocyte‐derived EVs and that these EVs promoted more VSMC adhesion and migration than those of healthy participants. We then established a macrophage foam cell model and characterized the EVs from the macrophages. We used flow cytometric analyses and cell migration and adhesion assays and determined that the foam cells generated more EVs than the normal macrophages and that the foam cell–derived EVs were capable of promoting increased levels of VSMC migration and adhesion. Furthermore, we performed a proteomic analysis of the EVs. The data showed that the foam cell–derived EVs may promote VSMC adhesion and migration by regulating the actin cytoskeleton and focal adhesion pathways. In addition, Western blotting revealed that foam cell–derived EVs could promote the phosphorylation of ERK and Akt in VSMCs in a time‐dependent manner. We also found that foam cell–derived EVs could enter the VSMCs and transfer integrins to the surface of these cells.

Conclusions

The data in our present study provide the first evidence that EVs from foam cells could promote VSMC migration and adhesion, which may be mediated by the integration of EVs into VSMCs and the subsequent downstream activation of ERK and Akt.

Relation among anti-rheumatic drug therapy, CD14(+)CD16(+) blood monocytes and disease activity markers (DAS28 and US7 scores) in rheumatoid arthritis: A pilot study

Circulating human monocytes, a functionally and phenotypically heterogeneous population, are emerging as fundamental cell types in rheumatoid arthritis (RA). The aim of this pilot study was to assess the correlation, if any, among anti-rheumatic drug therapy, circulating CD14(+)CD16(+) monocytes and validated clinical scales (e.g., DAS28 score and ultrasonography US7 score) of disease severity in RA. Thirty consecutive RA patients, either naïve or under disease-modifying anti-rheumatic drugs (DMARDs) or biological therapy, and 10 age-matched healthy volunteers, were enrolled. Monocytes were prepared from heparinized blood samples; surface expression of CD14 and CD16 was determined by flow cytometry. RA patients presented a significantly higher percentage of CD14(+)CD16(+) monocytes, as compared to healthy subjects. There was a good correlation between DAS28 clinical score and the ultrasound composite score US7 (r=0.66), as well as between both scores and the percentage of CD14(+)CD16(+) monocytes (r=0.43 and 0.47, respectively). Naïve RA patients had the highest expression (19.2±3.2%) of CD14(+)CD16(+) monocytes and elevated DAS28 score; patients on DMARDs presented a 7-fold increased expression of CD14(+)CD16(+) monocytes, relatively to healthy volunteers (2.1±1.4%), and an intermediate disease severity. The RA patients treated with biological therapy had a low percentage of CD14(+)CD16(+) monocytes (5.1±3.6%; p<0.01 vs naïve and DMARDs groups), similar to the one detected in healthy controls, and reduced US7 and DAS28 scores. Interestingly, for the same DAS28 score, monocytes isolated from RA patients on biological therapy had a lower CD16 expression than patients on DMARDs. Therefore, CD14(+)CD16(+) circulating blood monocytes may represent an appropriate biomarker to assess RA disease activity along with DAS28 and US7 scores. Together, these three parameters may represent a better indicator for evaluating therapy efficacy.

Montelukast potentiates the anticonvulsant effect of phenobarbital in mice: an isobolographic analysis

Although leukotrienes have been implicated in seizures, no study has systematically investigated whether the blockade of CysLT1 receptors synergistically increases the anticonvulsant action of classic antiepileptics. In this study, behavioral and electroencephalographic methods, as well as isobolographic analysis, are used to show that the CysLT1 inverse agonist montelukast synergistically increases the anticonvulsant action of phenobarbital against pentylenetetrazole-induced seizures. Moreover, it is shown that LTD4 reverses the effect of montelukast. The experimentally derived ED50mix value for a fixed-ratio combination (1:1 proportion) of montelukast plus phenobarbital was 0.06±0.02 μmol, whereas the additively calculated ED50add value was 0.49±0.03 μmol. The calculated interaction index was 0.12, indicating a synergistic interaction. The association of montelukast significantly decreased the antiseizure ED50 for phenobarbital (0.74 and 0.04 μmol in the absence and presence of montelukast, respectively) and, consequently, phenobarbital-induced sedation at equieffective doses. The demonstration of a strong synergism between montelukast and phenobarbital is particularly relevant because both drugs are already used in the clinics, foreseeing an immediate translational application for epileptic patients who have drug-resistant seizures.

Cysteinyl leukotriene receptor-1 antagonists as modulators of innate immune cell function

Cysteinyl leukotrienes (cysLTs) are produced predominantly by cells of the innate immune system, especially basophils, eosinophils, mast cells, and monocytes/macrophages. Notwithstanding potent bronchoconstrictor activity, cysLTs are also proinflammatory consequent to their autocrine and paracrine interactions with G-protein-coupled receptors expressed not only on the aforementioned cell types, but also on Th2 lymphocytes, as well as structural cells, and to a lesser extent neutrophils and CD8⁺ cells. Recognition of the involvement of cysLTs in the immunopathogenesis of various types of acute and chronic inflammatory disorders, especially bronchial asthma, prompted the development of selective cysLT receptor-1 (cysLTR1) antagonists, specifically montelukast, pranlukast, and zafirlukast. More recently these agents have also been reported to possess secondary anti-inflammatory activities, distinct from cysLTR1 antagonism, which appear to be particularly effective in targeting neutrophils and monocytes/macrophages. Underlying mechanisms include interference with cyclic nucleotide phosphodiesterases, 5′-lipoxygenase, and the proinflammatory transcription factor, nuclear factor kappa B. These and other secondary anti-inflammatory mechanisms of the commonly used cysLTR1 antagonists are the major focus of the current review, which also includes a comparison of the anti-inflammatory effects of montelukast, pranlukast, and zafirlukast on human neutrophils in vitro, as well as an overview of both the current clinical applications of these agents and potential future applications based on preclinical and early clinical studies.

Acute organ injury is associated with alterations in the cell-free plasma transcriptome

Background

Despite a genomic revolution in biological sciences, clinical medicine has yet to integrate diagnostics based upon gene expression into practice. While commonly used plasma protein assays rely on organ-specific origins, nearly all nucleic acid in whole blood is derived from white blood cells limiting their utility to diagnose non-immune disorders. The aim of the study was to use cell-free plasma to define circulating messenger RNA sequences diagnostic of acute organ injury, including myocardial infarction (MI) and acute kidney injury (AKI).

Methods

In healthy human subjects (N = 4) and patients with acute MI (N = 4), we characterized the concentration and nature of circulating plasma RNA through spectrophotometry and chromatography. Through reverse transcriptase polymerase chain reaction (RT-PCR) of amplicons up to 939 base pairs, we determined whether this mRNA was intact but of insufficient quantity to sequence. In mice, we induced an acute anterior myocardial infarction through 1 h of ischemia followed by reperfusion of the left anterior descending (LAD) artery. We compared the cell-free plasma transcriptome using cDNA microarray in sham-operated mice compared to ischemia upon reperfusion and at 1 and 4 h. To determine organ specificity, we compared this profile to acute ischemia-reperfusion of the kidney.

Results

In humans, there is more plasma RNA in those with acute MI than in healthy controls. In mice, ischemia-reperfusion of the LAD artery resulted in a time-dependent regulation of 589 circulating mRNA transcripts with less than a 5% overlap in sequences from acute ischemia-reperfusion injury of the kidney.

Conclusions

The mRNA derived from cell-free plasma defines organ injury in a time and injury-specific pattern.

Electronic supplementary material

The online version of this article (doi:10.1186/2197-425X-2-7) contains supplementary material, which is available to authorized users.