Quantifying proliferation of cultured human and rabbit airway smooth muscle cells in response to serum and platelet-derived growth factor

Upregulation of apoptotic genes and downregulation of target genes of Sonic Hedgehog signaling pathway in DAOY medulloblastoma cell line treated with arsenic trioxide

Sonic hedgehog (SHH) medulloblastoma etiology is associated with the SHH molecular pathway activation at different levels. We investigated the effect of arsenic trioxide as a downstream-level inhibitor of the SHH signaling pathway on morphology, cytotoxicity, migration, and SHH-related and apoptotic gene expression of DAOY cells. Cells were treated at various arsenic trioxide (ATO)concentrations (1, 2, 3, 5, and 10 μM) for different times (24 and 48 hr). Following treatments, the morphology of the cells was investigated at ×20 and ×40 magnification by an inverted microscope. Then, cytotoxicity was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and trypan blue assays. Cell migration was analyzed through the wound-healing assay. Furthermore, the expression of SHH-related (GLI1, GLI2, SMO, and MYCN) and apoptotic genes (BAX, BCL2, and TP53) was assessed by real-time quantitative polymerase chain reaction (qPCR). Finally, GLI1, SMO, and MYCN markers were analyzed through immunocytochemistry. Data were analyzed by SPSS (version 16) and P≤0.05 was considered significant. Morphological changes were seen at 3 and 2 μM in 24 and 48 hr of treatment, respectively. The MTT assay showed a dose-dependent cytotoxicity indicating an IC50 value of 3.39±0.35 and 2.05±0.64 μM in 24 and 48hr treatment, respectively. In addition, the trypan blue assay showed higher IC50 values of 4.29±0.25 and 3.92±0.22 μM in 24 and 48 hr treatment, respectively. The wound-healing assay indicated a dose-dependent reduction of cell migration speed showing a 50% reduction at 2.89±0.26 μM. Significant downregulation of GLI1 and GLI2, as well as the upregulation of BAX, BAX/BCL2 ratio, and TP53 were evident. Significant increases in GLI1 and MYCN markers were also evident in immunocytochemistry. ATO, as a downstream effective inhibitor of the SHH pathway, substantially leads to cell death, cell migration inhibition, apoptosis upregulation, and downregulation of SHH target genes in DAOY medulloblastoma. Since ATO is a toxic chemotherapeutic agent, it must be used at low concentrations (2 μM) in order not to damage healthy cells.

Bronchial smooth muscle cell in asthma: where does it fit?

Asthma is a frequent respiratory condition whose pathophysiology relies on altered interactions between bronchial epithelium, smooth muscle cells (SMC) and immune responses. Those leads to classical hallmarks of asthma: airway hyper-responsiveness, bronchial remodelling and chronic inflammation. Airway smooth muscle biology and pathophysiological implication in asthma are now better understood. Precise deciphering of intracellular signalling pathways regulating smooth muscle contraction highlighted the critical roles played by small GTPases of Rho superfamily. Beyond contractile considerations, active involvement of airway smooth muscle in bronchial remodelling mechanisms is now established. Not only cytokines and growth factors, such as fibroblats growth factor or transforming growth factor-β, but also extracellular matrix composition have been demonstrated as potent phenotype modifiers for airway SMC. Although basic science knowledge has grown significantly, little of it has translated into improvement in asthma clinical practice. Evaluation of airway smooth muscle function is still limited to its contractile activity. Moreover, it relies on tools, such as spirometry, that give only an overall assessment and not a specific one. Interesting technics such as forced oscillometry or specific imagery (CT and MRI) give new perspectives to evaluate other aspects of airway muscle such as bronchial remodelling. Finally, except for the refinement of conventional bronchodilators, no new drug therapy directly targeting airway smooth muscle proved its efficacy. Bronchial thermoplasty is an innovative and efficient therapeutic strategy but is only restricted to a small proportion of severe asthmatic patients. New diagnostic and therapeutic strategies specifically oriented toward airway smooth muscle are needed to improve global asthma care.

Role of NEAT1/MiR-9-5p/SLC26A2 Pathway on Human Airway Smooth Muscle Cell

PURPOSE

Asthma is a serious inflammatory disease of the respiratory system in which airway smooth muscle cells (ASMCs) play a key role. This study aimed to investigate the expression of SLC26A2 in human ASMCs (HASMCs) and the regulatory mechanism of SLC26A2 in the proliferation and inflammatory factor production of HASMCs.

MATERIALS AND METHODS

We obtained the asthma-associated differential mRNA SLC26A2 by bioinformatics analysis in childhood acute asthma samples. To investigate its role in airway inflammation and airway remodeling, we treated HASMCs with platelet-derived growth factor (PDGF) in an in vitro model and determined SLC26A2 expression in cells using western blotting. Cell proliferation was detected by MTT and EdU assays, and cell contractile phenotype marker proteins were measured. Cell migration and production of inflammatory factors were determined by Transwell and ELISA assays. Additionally, the upstream regulatory miRNA and LncRNA of SLC26A2 were identified by bioinformatics, luciferase reporter gene, and RIP analyses.

RESULTS

SLC26A2 was significantly upregulated in bioinformatics analysis of pediatric asthma-related sample. PDGF treatment up-regulated SLC26A2 expression in HASMCs, whereas the knockdown of SLC26A2 inhibited PDGF-stimulated proliferation, migration, and production of inflammatory factors, and enhanced the expression of cell contractile phenotype marker proteins in HASMCs. Luciferase reporter and RIP experiments validated that NEAT1 targeted miR-9-5p to regulate SLC26A2, thereby influencing the biological function of PDGF-induced HASMCs.

CONCLUSION

These findings indicate that NEAT1-mediated miR-9-5p targeting of SLC26A2 inhibits the PDGF-induced proliferation and production of inflammatory factors in HASMCs. These findings highlight potential therapeutic targets for asthma and airway inflammation.

Photo-crosslinked alginate nano-hydroxyapatite paste for bone tissue engineering

In this study, methacrylation of alginate was carried out by reacting sodium alginate with methacrylic anhydride in the presence of sodium hydroxide. Separately synthesized nano-hydroxyapatite (nano-HAp) powder was surface functionalized using mercaptopropionic acid and ethylene glycol methacrylate phosphate (EGMP) in the presence of azobisisobutyronitrile benzene as a free radical initiator in a nitrogen atmosphere. Methacrylated alginate solution was mixed with the required amount of surface-functionalized HAp nanoparticles in the presence of 0.05% Irgacure 2959 as a photoinitiator and was placed at the centre of a 8 kW UV light source (265 nm) to prepare photo-crosslinked bone paste. X-ray diffraction analysis indicated that surface functionalization did not alter phase purity of HAp nanopowder in the prepared paste. The graft polymerization of EGMP on the surface of HAp was confirmed by the presence of the 1732 cm^-1 band, which belongs to C=-O stretching of EGMP, in addition to the characteristic peaks of nano-HAp and alginate in the composite paste. The storage and loss moduli of all the prepared pastes increased non-linearly with time up to 100 s, demonstrating their pseudo plastic behaviour. The rate of release of bone morphogenetic protein 2 (BMP-2) was significantly faster in the first few days, and the release curve gradually levelled off prior to slowing down up to 22 d. Mesenchymal stem cell adhesion studies revealed that cells could attach to the paste material and stretch over the surface of the material after 14 d of incubation. MTT assay showed that prepared paste materials were conducive to attachment and proliferation of mesenchymal stem cells. Immunocytochemical analysis revealed that the addition of surface-functionalized nano-HAp and BMP-2 to alginate hydrogel enhanced the osteogenic potential of the prepared paste. The results indicate that the newly developed photo-crosslinked paste may be physically and biologically suitable for application as a bone filler.

Estrogen receptor beta signaling inhibits PDGF induced human airway smooth muscle proliferation

Airway smooth muscle (ASM) cell hyperplasia driven by persistent inflammation is a hallmark feature of remodeling in asthma. Sex steroid signaling in the lungs is of considerable interest, given epidemiological data showing more asthma in pre-menopausal women and aging men. Our previous studies demonstrated that estrogen receptor (ER) expression increases in asthmatic human ASM; however, very limited data are available regarding differential roles of ERα vs. ERβ isoforms in human ASM cell proliferation. In this study, we evaluated the effect of selective ERα and ERβ modulators on platelet-derived growth factor (PDGF)-stimulated ASM proliferation and the mechanisms involved. Asthmatic and non-asthmatic primary human ASM cells were treated with PDGF, 17β-estradiol, ERα-agonist and/or ERβ-agonist and/or G-protein-coupled estrogen receptor 30 (GPR30/GPER) agonist and proliferation was measured using MTT and CyQuant assays followed by cell cycle analysis. Transfection of small interfering RNA (siRNA) ERα and ERβ significantly altered the human ASM proliferation. The specificity of siRNA transfection was confirmed by Western blot analysis. Gene and protein expression of cell cycle-related antigens (PCNA and Ki67) and C/EBP were measured by RT-PCR and Western analysis, along with cell signaling proteins. PDGF significantly increased ASM proliferation in non-asthmatic and asthmatic cells. Treatment with PPT showed no significant effect on PDGF-induced proliferation, whereas WAY interestingly suppressed proliferation via inhibition of ERK1/2, Akt, and p38 signaling. PDGF-induced gene expression of PCNA, Ki67 and C/EBP in human ASM was significantly lower in cells pre-treated with WAY. Furthermore, WAY also inhibited PDGF-activated PCNA, C/EBP, cyclin-D1, and cyclin-E. Overall, we demonstrate ER isoform-specific signaling in the context of ASM proliferation. Activation of ERβ can diminish remodeling in human ASM by inhibiting pro-proliferative signaling pathways, and may point to a novel perception for blunting airway remodeling.

Blood MCP-1 levels are increased in chronic obstructive pulmonary disease patients with prevalent emphysema

Background and aims

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterized by different phenotypes with either bronchial airways alterations or emphysema prevailing. As blood biomarkers could be clinically useful for COPD stratification, we aimed at investigating the levels of blood biomarkers in COPD patients differentiated by phenotype: prevalent chronic airway disease versus emphysema.

Methods

In 23 COPD patients with prevalent airway disease (COPD-B), 22 COPD patients with prevalent emphysema (COPD-E), 9 control smokers (CSs), and 18 control nonsmokers (CNSs), we analyzed the expression levels of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, epidermal growth factor (EGF), monocyte chemotactic protein (MCP)-1, and vascular endothelial growth factor by enzyme-linked immunosorbent assay in plasma/serum; glutathione peroxidase and superoxide dismutase (SOD)-1 by immunochemical kits in plasma; and free F2-isoprostanes (F2-IsoPs) by gas chromatography in plasma.

Results

F2-IsoPs level was increased in COPD-B and COPD-E compared with CSs and CNSs; in addition, CS showed higher levels than CNSs; SOD1 level was lower in COPD-B and COPD-E than that in CNSs. Interestingly, MCP-1 level was higher only in COPD-E versus CSs and CNSs; EGF and IL-8 levels were higher in COPD-B and COPD-E versus CNSs; IL-6 level was increased in all three smoking groups (COPD-B, COPD-E, and CSs) versus CNS; IFN-γ and IL-1α levels were higher in CSs than in CNSs; and IL-1α level was also higher in CSs versus COPD-B and COPD-E. In all subjects, F2-IsoPs level correlated positively and significantly with MCP-1, IL-2, IL-1β, IFN-γ, and TNF-α and negatively with SOD1. When correlations were restricted to COPD-E and COPD-B groups, F2-IsoPs maintained the positive associations with IFN-γ, TNF-α, and IL-2.

Conclusion

We did not find any specific blood biomarkers that could differentiate COPD patients with prevalent airway disease from those with prevalent emphysema. The MCP-1 increase in COPD-E, associated with the imbalance of oxidant/antioxidant markers, may play a role in inducing emphysema.

Exposure to selected limonene oxidation products: 4-OPA, IPOH, 4-AMCH induces oxidative stress and inflammation in human lung epithelial cell lines

Limonene oxidation products (LOPs) have gained interest on their harmful health effects over time. Recently, studies have shown that the selected LOPs: 4-oxopentanal (4-OPA), 3-isopropenyl-6-oxo-heptanal (IPOH) and 4-acetyl-1-methylcyclohexene (4-AMCH) have sensory irritation effects in mice and inflammatory effects in human lung cells. This study was therefore undertaken to investigate the potential capacity of 4-OPA, IPOH and 4-AMCH to cause cell membrane damage, oxidative stress and inflammation in human bronchial (16HBE14o-) and alveolar (A549) epithelial cell lines. Overall results suggest that 4-OPA, IPOH have cytotoxic effects on human lung cells that might be mediated by ROS: the highest concentration applied of IPOH [500 μM] enhanced ROS generation by 100-fold ± 7.7 (A549) and 230-fold ± 19.9 (16HBE14o-) compared to the baseline. 4-OPA [500 μM] increased ROS levels by 1.4-fold ± 0.3 (A549) and by 127-fold ± 10.5 (16HBE14o-), while treatment with 4-AMCH [500 μM] led to 0.9-fold ± 0.2 (A549) and 49-fold ± 12.8 (16HBE14o-) increase. IPOH [500 μM] caused a decrease in the thiol-state balance (e.g. after 2 h, GSH:GSSG was reduced by 37% compared to the untreated 16HBE14o-cells). 4-OPA [500 μM] decreased the GSH:GSSG by 1.3-fold change in A549 cells and 1.4-fold change in 16HBE14o-cells. No statistically significant decrease in the GSH:GSSG in A549 and 16HBE14o-cell lines was observed for 4-AMCH [500 μM]. In addition, IPOH and 4-OPA [31.2 μM] increased the amount of the inflammatory markers: RANTES, VEGF and EGF. On the other hand, 4-AMCH [31.2 μM] did not show inflammatory effects in A549 or 16HBE14o-cells. The 4-OPA, IPOH and 4-AMCH treatment concentration and time-dependently induce oxidative stress and/or alteration of inflammatory markers on human bronchial and alveolar cell lines.

Inhibition of airway remodeling and inflammation by isoforskolin in PDGF-induced rat ASMCs and OVA-induced rat asthma model

Isoforskolin (ISOF) has been reported to play an important role in many illnesses including respiratory, cardiovascular and ophthalmologic diseases. In our study, we aimed to investigate how ISOF regulates airway remodeling and inflammation in asthma. Based on SO₂-stimulated mouse cough model, we assessed the role of ISOF in cough and secretion of phlegm. Afterwards, platelet derived growth factor (PDGF)-induced primary rat airway smooth muscle cell (ASMC) model and ovalbumin (OVA)-induced rat asthma model were used to continue our following research. Our results showed that ISOF could prolong the cough latent period, reduce the cough times in two minutes, and increase the excretion of red phenol, which suggested the antitussive and expectorant effects of ISOF. Besides, ISOF pretreatment reversed the hypotonicity and cytoskeleton remodeling in PDGF-induced ASMCs, and reduced mucus hypersecretion and collagen overdeposition in OVA-induced rat asthma model, which indicated its inhibition on airway remodeling in vitro and in vivo. Moreover, ISOF reduced the invasion of inflammatory cells into bronchoalveolar lavage fluid (BALF) and lungs, which revealed its inhibitory role in airway inflammation. The down-regulation of transforming growth factor β1 (TGF-β1) and interleukin-1β (IL-1β) upon ISOF treatment might be responsible for its anti-remodeling and anti-inflammation roles. In conclusion, ISOF can reduce cough and sputum, as well as inhibit airway remodeling and inflammation by regulating the expression of TGF-β1 and IL-1β. These data indicate the potency of ISOF in treating asthma and also provide insights into the development of new anti-asthma agent.

Inundation of asthma target research: Untangling asthma riddles

Asthma is an inveterate inflammatory disorder, delineated by the airway inflammation, bronchial hyperresponsiveness (BHR) and airway wall remodeling. Although, asthma is a vague term, and is recognized as heterogenous entity encompassing different phenotypes. Targeting single mediator or receptor did not prove much clinical significant, as asthma is complex disease involving myriad inflammatory mediators. Asthma may probably involve a large number of different types of molecular and cellular components interacting through complex pathophysiological pathways. This review covers the past, present, and future therapeutic approaches and pathophysiological mechanisms of asthma. Furthermore, review describe importance of targeting several mediators/modulators and receptor antagonists involved in the physiopathology of asthma. Novel targets for asthma research include Galectins, Immunological targets, K ⁺ Channels, Kinases and Transcription Factors, Toll-like receptors, Selectins and Transient receptor potential channels. But recent developments in asthma research are very promising, these include Bitter taste receptors (TAS2R) abated airway obstruction in mouse model of asthma and Calcium-sensing receptor obliterate inflammation and in bronchial hyperresponsiveness allergic asthma. All these progresses in asthma targets, and asthma phenotypes exploration are auspicious in untangling of asthma riddles.

Characterising the mechanism of airway smooth muscle β2 adrenoceptor desensitization by rhinovirus infected bronchial epithelial cells

Rhinovirus (RV) infections account for approximately two thirds of all virus-induced asthma exacerbations and often result in an impaired response to β2 agonist therapy. Using an in vitro model of RV infection, we investigated the mechanisms underlying RV-induced β2 adrenoceptor desensitization in primary human airway smooth muscle cells (ASMC). RV infection of primary human bronchial epithelial cells (HBEC) for 24 hours produced conditioned medium that caused β2 adrenoceptor desensitization on ASMCs without an effect on ASMCs viability. Less than 3 kDa size fractionation together with trypsin digestion of RV-induced conditioned medium did not prevent β2 adrenoceptor desensitization, suggesting it could potentially be mediated by a small peptide or lipid. RV infection of BECs, ASMCs and fibroblasts produced prostaglandins, of which PGE2, PGF2α and PGI2 had the ability to cause β2 adrenoceptor desensitization on ASMCs. RV-induced conditioned medium from HBECs depleted of PGE2 did not prevent ASMC β2 adrenoceptor desensitization; however this medium induced PGE2 from ASMCs, suggesting that autocrine prostaglandin production may be responsible. Using inhibitors of cyclooxygenase and prostaglandin receptor antagonists, we found that β2 adrenoceptor desensitization was mediated through ASMC derived COX-2 induced prostaglandins. Since ASMC prostaglandin production is unlikely to be caused by RV-induced epithelial derived proteins or lipids we next investigated activation of toll-like receptors (TLR) by viral RNA. The combination of TLR agonists poly I:C and imiquimod induced PGE2 and β2 adrenoceptor desensitization on ASMC as did the RNA extracted from RV-induced conditioned medium. Viral RNA but not epithelial RNA caused β2 adrenoceptor desensitization confirming that viral RNA and not endogenous human RNA was responsible. It was deduced that the mechanism by which β2 adrenoceptor desensitization occurs was by pattern recognition receptor activation of COX-2 induced prostaglandins.

Development and characterization of a 3D multicell microtissue culture model of airway smooth muscle

Airway smooth muscle (ASM) cellular and molecular biology is typically studied with single-cell cultures grown on flat 2D substrates. However, cells in vivo exist as part of complex 3D structures, and it is well established in other cell types that altering substrate geometry exerts potent effects on phenotype and function. These factors may be especially relevant to asthma, a disease characterized by structural remodeling of the airway wall, and highlights a need for more physiologically relevant models of ASM function. We utilized a tissue engineering platform known as microfabricated tissue gauges to develop a 3D culture model of ASM featuring arrays of ∼0.4 mm long, ∼350 cell "microtissues" capable of simultaneous contractile force measurement and cell-level microscopy. ASM-only microtissues generated baseline tension, exhibited strong cellular organization, and developed actin stress fibers, but lost structural integrity and dissociated from the cantilevers within 3 days. Addition of 3T3-fibroblasts dramatically improved survival times without affecting tension development or morphology. ASM-3T3 microtissues contracted similarly to ex vivo ASM, exhibiting reproducible responses to a range of contractile and relaxant agents. Compared with 2D cultures, microtissues demonstrated identical responses to acetylcholine and KCl, but not histamine, forskolin, or cytochalasin D, suggesting that contractility is regulated by substrate geometry. Microtissues represent a novel model for studying ASM, incorporating a physiological 3D structure, realistic mechanical environment, coculture of multiple cells types, and comparable contractile properties to existing models. This new model allows for rapid screening of biochemical and mechanical factors to provide insight into ASM dysfunction in asthma.

The effects of intravenous anesthetics on mouse embryonic fibroblast viability and proliferation

PURPOSE

The aim of this study is to evaluate the cytotoxic and antiproliferating effects of intravenous anesthetics on an mouse fibroblast in vitro cell culture system.

METHODS

The cells were exposed to the usual clinical plasma concentration of intravenous anesthetics, i.e., midazolam (0.15 μg/ml), propofol (2 μg/ml), remifentanil (2 μg/ml), thiopental (10 μg/ml), for 4, 8, or 24 h. Cell proliferation (n = 6 for each) under intravenous anesthetics was analyzed using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Cytotoxicity (n = 6 for each) of intravenous anesthetics was investigated using a LIVE/DEAD viability assay kit.

RESULTS

Intravenous anesthetic exposure time did not affect the proliferation rate of mouse fibroblasts. The cytotoxicity of intravenous anesthetics did not differ in accordance with exposure time.

CONCLUSION

Our results showed that intravenous anesthetics may not affect mouse fibroblast proliferation and viability.

Enhanced vascular permeability is hypothesized to promote inflammation-induced carcinogenesis and tumor development via extravasation of large molecular proteins into the tissue

We propose that the growth of solid tumors is dependent, in part, on the entry of large molecular blood-borne growth regulators into the tissue and is facilitated by the highly permeable nature of tumor blood vessels. There is abundant evidence that the tumor vasculature is hyperpermeable and tumor growth is dependent on mediators that increase vascular permeability (e.g., VEGF and mast cells). Therefore, the extravasation of plasma proteins into the interstitial space could be an important determinant of tumor growth. Angiogenesis promotes cancer by creating a network of blood vessels that supplies oxygen and nutriment. A highly permeable vasculature could complement this by facilitating the entry of plasma proteins into the tumor space, permitting them to exert effects on growth and survival pathways. Plasma proteins could act directly (on the cancer cells) or indirectly (via the stroma), and could conceivably stimulate cell proliferation, enhance cell survival, promote angiogenesis, and/or provide the cells with essential nutrients. Since increased vascular permeability is a hallmark of inflammation and since chronic inflammation is a forerunner to cancer, we also suggest that the prolonged influx of plasma proteins during chronic inflammation could contribute to the carcinogenic process. Perhaps over time and in sufficient quantity, the extruded plasma proteins and the attendant edema set up a feed-forward cycle that exacerbates the inflammation and potentiates the formation of mutagens and growth regulators. It is tempting to speculate that differences in tumor growth/metastasis and patient outcome are at least partly due to the degree of permeability of the tumor vasculature.

Motility, survival, and proliferation

Airway smooth muscle has classically been of interest for its contractile response linked to bronchoconstriction. However, terminally differentiated smooth muscle cells are phenotypically plastic and have multifunctional capacity for proliferation, cellular hypertrophy, migration, and the synthesis of extracellular matrix and inflammatory mediators. These latter properties of airway smooth muscle are important in airway remodeling which is a structural alteration that compounds the impact of contractile responses on limiting airway conductance. In this overview, we describe the important signaling components and the functional evidence supporting a view of smooth muscle cells at the core of fibroproliferative remodeling of hollow organs. Signal transduction components and events are summarized that control the basic cellular processes of proliferation, cell survival, apoptosis, and cellular migration. We delineate known intracellular control mechanisms and suggest future areas of interest to pursue to more fully understand factors that regulate normal myocyte function and airway remodeling in obstructive lung diseases.

Rhinovirus infection induces extracellular matrix protein deposition in asthmatic and nonasthmatic airway smooth muscle cells

Airway remodeling, which includes increases in the extracellular matrix (ECM), is a characteristic feature of asthma and is correlated to disease severity. Rhinovirus (RV) infections are associated with increased risk of asthma development in young children and are the most common cause of asthma exacerbations. We examined whether viral infections can increase ECM deposition and whether this increased ECM modulates cell proliferation and migration. RV infection of nonasthmatic airway smooth muscle (ASM) cells significantly increased the deposition of fibronectin (40% increase, n = 12) and perlecan (80% increase, n = 14), while infection of asthmatic ASM cells significantly increased fibronectin (75% increase, n = 9) and collagen IV (15% increase, n = 9). We then treated the ASM cells with the Toll-like receptor (TLR) agonists polyinosinic:polycytidylic acid, imiquimod, and pure RV RNA and were able to show that the mechanism through which RV induced ECM deposition was via the activation of TLR3 and TLR7/8. Finally, we assessed whether the virus-induced ECM was bioactive by measuring the amount of migration and proliferation of virus-naive cells that seeded onto the ECM. Basically, ECM from asthmatic ASM cells induced twofold greater migration of virus-naive ASM cells than ECM from nonasthmatic ASM cells, and these rates of migration were further increased on RV-modulated ECM. Increased migration on the RV-modulated ECM was not due to increased cell proliferation, as RV-modulated ECM decreased the proliferation of virus-naive cells. Our results suggest that viruses may contribute to airway remodeling through increased ECM deposition, which in turn may contribute to increased ASM mass via increased cell migration.

Fibulin-1 is increased in asthma--a novel mediator of airway remodeling?

Background

The extracellular matrix is a dynamic and complex network of macromolecules responsible for maintaining and influencing cellular functions of the airway. The role of fibronectin, an extracellular matrix protein, is well documented in asthma. However, the expression and function of fibulin-1, a secreted glycoprotein which interacts with fibronectin, has not been reported. Fibulin-1 is widely expressed in basement membranes in many organs including the lung. There are four isoforms in humans (A–D) of which fibulin-1C and 1D predominate. The objective of this study was to study the expression of fibulin-1 in volunteers with and without asthma, and to examine its function in vitro.

Methodology/Principal Findings

We used immunohistochemistry and dot-blots to examine fibulin-1 levels in bronchial biopsies, bronchoalveolar lavage fluid and serum. Real-time PCR for fibulin-1C and 1D, and ELISA and western blotting for fibulin-1 were used to study the levels in airway smooth muscle cells. The function of fibulin-1C was determined by assessing its role, using an antisense oligonucleotide, in cell proliferation, migration and wound healing. A murine model of airway hyperresponsiveness (AHR) was used to explore the biological significance of fibulin-1. Levels of fibulin-1 were significantly increased in the serum and bronchoalveolar lavage fluid of 21 asthmatics compared with 11 healthy volunteers. In addition fibulin-1 was increased in asthma derived airway smooth muscle cells and fibulin-1C contributed to the enhanced proliferation and wound repair in these cells. These features were reversed when fibulin-1C was suppressed using an antisense oligomer. In a mouse model of AHR, treatment with an AO inhibited the development of AHR to methacholine.

Conclusions

Our data collectively suggest fibulin-1C may be worthy of further investigation as a target for airway remodeling in asthma.

MUC4 down-regulation reverses chemoresistance of pancreatic cancer stem/progenitor cells and their progenies

The present study was undertaken to estimate the therapeutic benefit to down-regulate the MUC4 mucin for reversing chemoresistance of pancreatic cancer (PC) stem/progenitor cells and their progenies. The results have revealed that MUC4 mucin is overexpressed in CD133(+) and CD133(-) pancreatic cells (PCs) detected in patient's adenocarcinoma tissues while no significant expression was seen in normal pancreatic tissues. The gain- and loss-of-function analyses have indicated that the overexpression of MUC4 in PC lines is associated with a higher resistance to the anti-proliferative, anti-invasive and apoptotic effects induced by gemcitabine. Importantly, the treatment of the MUC4-overexpressing CD18/HPAF-Src cells with gemcitabine resulted in an enrichment of the side population (SP) cells expressing CD133 while the total PC cells including non-SP cells detected in MUC4 knockdown CD18/HPAF-shMUC4 cells were responsive to the cytotoxic effects induced by gemcitabine. These data suggest that the MUC4 down-regulation may constitute a potential therapeutic strategy for improving the efficacy of gemcitabine to eradicate the total PC cell mass, and thereby preventing disease relapse.

Cytotoxic effects induced by docetaxel, gefitinib, and cyclopamine on side population and nonside population cell fractions from human invasive prostate cancer cells

The present study has been undertaken to establish the therapeutic benefit of cotargeting epidermal growth factor receptor (EGFR) and sonic hedgehog pathways by using gefitinib and cyclopamine, respectively, for improving the efficacy of the current chemotherapeutic drug docetaxel to counteract the prostate cancer progression from locally invasive to metastatic and recurrent disease stages. The data from immuofluorescence analyses revealed that EGFR/Tyr(1173)-pEGFR, sonic hedgehog ligand, smoothened coreceptor, and GLI-1 were colocalized with the CD133(+) stem cell-like marker in a small subpopulation of prostate cancer cells. These signaling molecules were also present in the bulk tumor mass of CD133(-) prostate cancer cells with a luminal phenotype detected in patient's adenocarcinoma tissues. Importantly, the results revealed that the CD133(+)/CD44(high)/AR(-/low) side population (SP) cell fraction endowed with a high self-renewal potential isolated from tumorigenic and invasive WPE1-NB26 cells by the Hoechst dye technique was insensitive to the current chemotherapeutic drug, docetaxel. In contrast, the docetaxel treatment induced significant antiproliferative and apoptotic effects on the CD133(-)/CD44(low)/AR(+) non-SP cell fraction isolated from the WPE1-NB26 cell line. Of therapeutic interest, the results have also indicated that combined docetaxel, gefitinib, and cyclopamine induced greater antiproliferative and apoptotic effects on SP and non-SP cell fractions isolated from WPE1-NB26 cells than individual drugs or two-drug combinations. Altogether, these observations suggest that EGFR and sonic hedgehog cascades may represent the potential therapeutic targets of great clinical interest to eradicate the total prostate cancer cell mass and improve the current docetaxel-based therapies against locally advanced and invasive prostate cancers, and thereby prevent metastases and disease relapse.

Noncontractile functions of airway smooth muscle cells in asthma

Although pivotal in regulating bronchomotor tone in asthma, airway smooth muscle (ASM) also modulates airway inflammation and undergoes hypertrophy and hyperplasia, contributing to airway remodeling in asthma. ASM myocytes secrete or express a wide array of immunomodulatory mediators in response to extracellular stimuli, and in chronic severe asthma, increases in ASM mass may render the airway irreversibly obstructed. Although the mechanisms by which ASM secretes cytokines and chemokines are the same as those regulating immune cells, there exist unique ASM signaling pathways that may provide novel therapeutic targets. This review provides an overview of our current understanding of the proliferative as well as the synthetic properties of ASM.

Platelet-derived growth factor and transforming growth factor-beta modulate the expression of matrix metalloproteinases and migratory function of human airway smooth muscle cells

BACKGROUND

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) have been suggested to be involved in the pathogenesis of asthma. Their expression in airway smooth muscle (ASM) cells could be involved in collagen turnover and migration of these cells and thus may contribute to airway remodelling.

OBJECTIVE

To examine the effect of pro-fibrotic growth factors TGF-beta and platelet-derived growth factor (PDGF) on the expression of MMPs/TIMPs in cultured human ASM cells and to examine the role of MMP in the migration of ASM cells.

METHODS

ASM cells were stimulated with TGF-beta and/or PDGF. Expression and activity of MMP-1, MMP-2, MMP-3, TIMP-1 and TIMP-2 were evaluated by quantitative RT-PCR, Western blot and zymography. Modified Boyden-chamber migration assay was performed to investigate the effect of secreted MMP-3 and TIMP-1 on ASM-cell migration.

RESULTS

PDGF strongly up-regulated the expression of MMP-1 at mRNA and protein levels. PDGF, when combined with TGF-beta, caused synergistic up-regulation of MMP-3. TIMP-1 was additively up-regulated by TGF-beta and PDGF. These growth factors had no effect on the expression of MMP-2 and TIMP-2. U0126, an extracellular signal-regulated kinase (ERK) pathway inhibitor, inhibited the up-regulation of MMP-1 by PDGF. The synergistic/additive up-regulation of MMP-3 and TIMP-1 was inhibited by U0126 and SB431542, a Smad pathway inhibitor. Supernatant from ASM cells in which MMP-3 production was knocked down by RNA interference showed a decreased migratory effect on ASM cells, whereas supernatant from cells with suppressed TIMP-1 expression resulted in increased migration.

CONCLUSION

Our results suggest that PDGF with/without TGF-beta could facilitate migration of ASM cells by modification of MMP-TIMP balance through the ERK pathway.

Liver X receptor agonists increase airway reactivity in a model of asthma via increasing airway smooth muscle growth

The liver X receptors (LXRalpha/beta) are orphan nuclear receptors that are expressed in a large number of cell types and have been shown to have anti-inflammatory properties. Nuclear receptors have previously proved to be amenable targets for small molecular mass pharmacological agents in asthma, and so the effect of an LXR ligand was assessed in models of allergic airway inflammation. LXR agonist, GW 3965, was profiled in rat and mouse models of allergic asthma. In the Brown Norway rats, GW 3965 (3-30 mg/kg) was unable to reduce the bronchoalveolar lavage eosinophilia associated with this model and had no impact on inflammatory biomarkers (eotaxin and IL-1beta). The compound did significantly stimulate ABCA-1 (ATP-binding cassette A1) mRNA expression, indicating that there was adequate exposure/LXR activation. In the mouse model, the LXR ligand surprisingly increased airway reactivity, an effect that was apparent in both the Ag and nonchallenged groups. This increase was not associated with a change in lung tissue inflammation or number of mucus-containing cells. There was, however, a marked increase in airway smooth muscle thickness in both treated groups. We demonstrated an increase in contractile response to exogenous methacholine in isolated airways taken from LXR agonist-treated animals compared with the relevant control tissue. We corroborated these findings in a human system by demonstrating increased proliferation of cultured airway smooth muscle. This phenomenon, if evidenced in man, would indicate that LXR ligands may directly increase airway reactivity, which could be detrimental, especially in patients with existing respiratory disease and with already compromised lung function.

Airway smooth muscle in asthma

Airway smooth muscle plays a multifaceted role in the pathogenesis of asthma. We review the current understanding of the contribution of airway myocytes to airway inflammation, airway wall remodeling, and airflow obstruction in this prevalent disease syndrome. Together, these roles make airway smooth muscle an attractive target for asthma therapy.

Pharmacology of airway smooth muscle proliferation

Airway smooth muscle thickening is a pathological feature that contributes significantly to airflow limitation and airway hyperresponsiveness in asthma. Ongoing research efforts aimed at identifying the mechanisms responsible for the increased airway smooth muscle mass have indicated that hyperplasia of airway smooth muscle, due in part to airway myocyte proliferation, is likely a major factor. Airway smooth muscle proliferation has been studied extensively in culture and in animal models of asthma, and these studies have revealed that a variety of receptors and mediators contributes to this response. This review aims to provide an overview of the receptors and mediators that control airway smooth muscle cell proliferation, with emphasis on the intracellular signalling mechanisms involved.

Airway smooth muscle growth in asthma: proliferation, hypertrophy, and migration

Increased airway smooth muscle mass is present in fatal and non-fatal asthma. However, little information is available regarding the cellular mechanism (i.e., hyperplasia vs. hypertrophy). Even less information exists regarding the functional consequences of airway smooth muscle remodeling. It would appear that increased airway smooth muscle mass would tend to increase airway narrowing and airflow obstruction. However, the precise effects of increased airway smooth muscle mass on airway narrowing are not known. This review will consider the evidence for airway smooth muscle cell proliferation and hypertrophy in asthma, potential functional effects, and biochemical mechanisms.

Transforming growth factor beta 1 increases fibronectin deposition through integrin receptor alpha 5 beta 1 on human airway smooth muscle

BACKGROUND

Integrin receptors signal to and from the extracellular matrix. Altered expression of the integrin receptors, such as the fibronectin receptor alpha(5)beta(1), might be implicated in extracellular matrix accumulation in airway remodeling in asthma.

OBJECTIVE

We examined the effect of TGF-beta stimulation on integrin alpha(5)beta(1) expression and the role of alpha(5)beta(1) in fibronectin deposition and proliferation.

METHODS

Integrin subunit alpha(5) and beta(1) expression in airway smooth muscle (ASM) from subjects with and without asthma was examined by means of PCR and flow cytometry. The effect of blocking alpha(5)beta(1) receptor on ASM proliferation to FBS was assessed by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay. Cells were stimulated with TGF-beta in the presence or absence of extracellular signal-regulated kinase, phosphoinositide-3 kinase, or p38 inhibitors and antibodies to the alpha(5) and beta(1) subunits. The effect of blocking alpha(5)beta(1) receptor on fibronectin deposition was assessed by means of immunocytochemistry.

RESULTS

Proliferation of ASM cells from asthmatic and nonasthmatic subjects was inhibited by blocking the fibronectin receptor subunit alpha(5)beta(1). TGF-beta-induced alpha(5)beta(1) was extracellular signal-regulated kinase dependent but not phosphoinositide-3 kinase or p38 dependent. Blockade of the alpha(5)beta(1) receptor inhibited TGF-beta-induced fibronectin matrix deposition.

CONCLUSION

Through its increased expression by the profibrotic stimulus TGF-beta, integrin alpha(5)beta(1) might be important in regulating fibronectin deposition.

Improvement of cytotoxic effects induced by mitoxantrone on hormone-refractory metastatic prostate cancer cells by co-targeting epidermal growth factor receptor and hedgehog signaling cascades

The results of the present study revealed for the first time the possibility to use a combination of mitoxantrone with gefitinib and cyclopamine for inhibiting the growth of epidermal growth factor (EGF), sonic hedgehog- (SHHNp), and serum-stimulated androgen-sensitive LNCaP-C33 and androgen-independent (AI) LNCaP-C81, DU145 and PC3 prostate cancer (PC) cells. The supra-additive anti-proliferative effects of drugs were mediated via a blockade of the PC3 cells in the G(1) and G(2)M phases of the cell cycle. Importantly, the combination of mitoxantrone plus gefitinib and/or cyclopamine also caused a higher rate of apoptotic death of PC cells including enriched fraction of CD44(high) PC3 cell subpopulation as compared to the individual agents or bi-combination of drugs. The cytotoxic effects induced by mitoxantrone, gefitinib and cyclopamine on PC3 cells appear to be at least partly mediated through the depolarization of the mitochondrial membrane, release of cytochrome c into the cytosol, hydrogen peroxide production and activation of caspase cascades. These findings indicate that the simultaneous blockade of EGF-EGFR and sonic hedgehog tumorigenic signaling cascades may represent a promising strategy for improving the efficacy of current mitoxantrone-based therapies against incurable AI and metastatic PCs in the clinics.

Novel uses for anti-platelet agents as anti-inflammatory drugs

An alteration in the character and function of platelets is manifested in patients with inflammatory diseases, and these alterations have been dissociated from the well-characterized involvement of platelets in thrombosis and haemostasis. Recent evidence reveals platelet activation is sometimes critical in the development of inflammation. The mechanisms by which platelets participate in inflammation are diverse, and offer numerous opportunities for future drug intervention. There is now acceptance that platelets act as innate inflammatory cells in immune responses, with roles as sentinel cells undergoing surveillance, responding to microbial invasion, orchestrating leukocyte recruitment, and migrating through tissue, causing damage and influencing repair processes in chronic disease. Some of these processes are targeted by drugs that are being developed to target platelet participation in atherosclerosis. The actions of platelets therefore influence the pathogenesis of diverse inflammatory diseases in various body compartments, encompassing parasitic and bacterial infection, allergic inflammation (especially asthma and rhinitis), and non-atopic inflammatory conditions, for example, chronic obstructive pulmonary disease (COPD), rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and atherosclerosis. This review will first discuss the evidence for platelet activation in these various inflammatory diseases, and secondly discuss the mechanisms by which this pathogenesis occurs and the various anti-platelet agents which have been developed to combat platelet activation in atherosclerosis and their potential future use for the treatment of other inflammatory diseases.

Combined targeting of epidermal growth factor receptor and hedgehog signaling by gefitinib and cyclopamine cooperatively improves the cytotoxic effects of docetaxel on metastatic prostate cancer cells

The epidermal growth factor receptor (EGFR) and hedgehog cascades provide a critical role in prostate cancer progression and contribute to the resistance to clinical therapies and disease relapse. Therefore, we evaluated, for the first time, the antiproliferative and cytotoxic effects induced by a combination of selective inhibitors of EGFR tyrosine kinase and smoothened hedgehog signaling element, gefitinib and cyclopamine, with a current chemotherapeutic drug used in the clinics, docetaxel, on some metastatic prostate cancer cell lines. Immunohistochemical analyses revealed that sonic hedgehog (SHH) expression was enhanced in 39% of primary prostatic adenocarcinomas (Gleason scores 4-10) compared with the corresponding normal tissues of the same prostate gland from 32 prostate cancer patients. The confocal microscopy and Western blot analyses have also indicated the high expression levels of SHH and EGFR in metastatic LNCaP, DU145, and PC3 cells. Moreover, the results revealed that the drugs, alone or in combination, at lower concentrations inhibited the growth of EGF plus SHH-stimulated and serum-stimulated androgen-responsive LNCaP-C33 and androgen-independent LNCaP-C81, DU145, and PC3 cells. Importantly, the combined docetaxel, gefitinib, and cyclopamine also caused a higher rate of apoptotic death of prostate cancer cells compared with individual agents. The cytotoxic effects induced by these drugs in PC3 cells seem to be mediated in part through the cellular ceramide production and activation of caspase cascades via a mitochondrial pathway and the release of cytochrome c into the cytosol. Additionally, the combined agents were more effective at suppressing the invasiveness of PC3 cells through Matrigel in vitro than the single drugs. These findings indicate that the combined use of inhibitors of EGF-EGFR and hedgehog signaling with docetaxel could represent a more promising strategy for treatment in patients with metastatic and androgen-independent prostate cancer.

TNF-alpha induced CD38 expression in human airway smooth muscle cells: role of MAP kinases and transcription factors NF-kappaB and AP-1

In human airway smooth muscle (HASM) cells, the expression of CD38, which synthesizes the calcium-mobilizing molecule cyclic ADP-ribose, is augmented by TNF-alpha, a cytokine implicated in asthma. We determined the role of mitogen-activated protein kinase (MAPK) in the activation of NF-kappaB and AP-1 in the regulation of CD38 expression in HASM cells. In HASM cells exposed to TNF-alpha (40 ng/ml), the inhibitors of extracellular signal-regulated kinase (ERK), p38, or c-Jun NH(2)-terminal kinase (JNK) decreased CD38 expression and ADP-ribosyl cyclase activity. Transfection of HASM cells with a dominant negative MEK decreased while a wild-type ERK increased TNF-alpha-induced CD38 expression. Electrophoretic mobility shift assays (EMSAs) were performed using nuclear proteins and consensus sequences to detect the effect of the MAPKs on NF-kappaB and AP-1 activation. EMSAs confirmed the role of p38 and JNK in mediating NF-kappaB and AP-1 activation. Transfection of a dominant negative c-Jun decreased TNF-alpha-induced CD38 expression indicating involvement of AP-1. Stability of TNF-alpha-induced CD38 transcripts were determined in the presence of MAPK inhibitors after arresting the transcription with actinomycin D. Transcript stability decreased in the presence of ERK and p38 MAPK, but not the JNK, inhibitors. These results indicate that regulation of CD38 expression through p38 and JNK MAPKs involves NF-kappaB and AP-1 activation, and ERK and p38 MAPKs also regulate expression posttranscriptionally through message stability.

Novel combination therapy against metastatic and androgen-independent prostate cancer by using gefitinib, tamoxifen and etoposide

In this study, we evaluated, for the first time, the antiproliferative and cytotoxic effects induced by a combination of a selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, gefitinib, with other chemotherapeutic drugs including estrogen receptor-beta (ER-beta) antagonist (tamoxifen) and topoisomerase II inhibitor (etoposide) on some metastatic prostate cancer (PC) cell lines. Immunohistochemial analyses revealed that EGFR expression was enhanced in 38% of primary prostatic adenocarcinomas (Gleason scores 4-10) as compared to the corresponding normal tissues of the same prostate gland from 32 PC patients. The RT-PCR and Western blot data have also indicated the higher expression levels of EGFR and ER-beta transcripts and proteins in metastatic LNCaP, DU145 and PC3 cells relative to nonmalignant normal prostate cells. Moreover, the results from MTT and FACS analyses revealed that the drugs, alone or in combination at lower concentrations, inhibited the growth of 17beta-estradiol (E2) plus EGF and serum-stimulated androgen-responsive LNCaP-C33 and androgen-independent LNCaP-C81, DU145 and PC3 cells. Importantly, the combined gefitinib, tamoxifen and etoposide also caused a higher rate of apoptotic death of PC cells as compared to single agents. The cytotoxic effects induced by these drugs in PC3 cells appear to be mediated through the accumulation of cellular ceramide and activation of caspase cascades via a mitochondrial pathway. These findings indicate that the combined use of inhibitors of EGF-EGFR and E2-ER-beta signaling with etoposide, which act by increasing the cellular ceramide levels and caspase activity, represents a promising strategy for a more effective treatment of metastatic PC forms.

Cytotoxic effects induced by a combination of cyclopamine and gefitinib, the selective hedgehog and epidermal growth factor receptor signaling inhibitors, in prostate cancer cells

Although the blockade of the hedgehog cascade by using cyclopamine has been reported to inhibit the growth of some cancer cell types, few studies on the mechanism by which this drug alone or in combination with other cytotoxic agents induces its cytotoxic effect have been reported. In our study, we evaluate, for the first time, the antiproliferative and cytotoxic effects induced by a combination of selective SMO inhibitor, cyclopamine and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, gefitinib on metastatic prostate cancer (PC) cells. The results revealed that cyclopamine, alone or at a lower concentration in combination with gefitinib, inhibited the growth of sonic hedgehog- (SHH), epidermal growth factor- (EGF) and serum-stimulated androgen-sensitive LNCaP-C33 and LNCaP-LN3 and androgen-independent LNCaP-C81, DU145 and PC3 cells. The antiproliferative effect of cyclopamine and gefitinib, alone or in combination, was mediated via a blockade of the PC3 cells in the G1 phase of the cell cycle. Importantly, the combined cyclopamine and gefitinib also caused a higher rate of apoptotic death of PC cells compared to single agents. The cytotoxic effect induced by these drugs in PC3 cells appears to be mediated at least, in part, via the mitochondrial pathway through the depolarization of the mitochondrial membrane and the release of cytochrome c and reactive oxygen species into the cytosol. This was also accompanied by the activation of caspase cascades, PARP cleavage and DNA fragmentation. Additionally, the combined cyclopamine and gefitinib were more effective at suppressing the invasiveness of PC3 cells through matrigel in vitro as the drugs alone. These findings indicate that the simultaneous blockade of SHH-GLI-1 and EGF-EGFR signaling, which results in the growth arrest and massive rate of apoptotic cell death, represents a promising strategy for a more effective treatment of metastatic PC forms.

Human airway smooth muscle cells express eotaxin in response to signaling following mast cell contact

BACKGROUND

Asthma is a chronic inflammatory disease of the airways. Mast-cell (MC)-derived cytokines may mediate both airway inflammation and remodeling. It has also been shown that airway smooth muscle cells (ASMC) can be a source of proinflammatory cytokines. In the human airways, MC-ASMC cell interactions may have pivotal effects on modulating inflammation.

OBJECTIVES

We wanted to know whether the production of eotaxin, an important proinflammatory cytokine, through a cell-to-cell contact mechanism of human ASMC activation by MC was mediated by p38 MAPK.

METHODS

We cocultured normal humanASMC with a human MC line (HMC-1) and assayed for the production of eotaxin.

RESULTS

When cultured together, human ASMC and HMC-1 contact induced eotaxin secretion. Separation of HMC-1 and human ASMC by a porous membrane inhibited this induction. Coculturing of human ASMC with HMC-1 induced increased expression of eotaxin gene mRNA. HMC-1-derived cellular membranes caused an increase in eotaxin production in human ASMC. Activation of p38 MAPK was also seen in cocultures by Western blot, whereas eotaxin production in cocultures was significantly inhibited by the p38 inhibitor SB203580.

CONCLUSION

These novel studies reveal the importance of cell-to-cell interactions in the complex milieu of airway inflammation.

Some structural determinants of the antiproliferative effect of heparin-like molecules on human airway smooth muscle

Accumulation of airway smooth muscle (ASM) and its infiltration by mast cells are key pathological features of airway remodelling in asthma. Heparin, a major component of mast cell granules, inhibits ASM proliferation by an unknown mechanism. Here, unfractionated heparins and related glycosaminoglycans having structurally heterogeneous polysaccharide side chains that varied in molecular weight, sulphation and anionic charge were used to identify features of the heparin molecule that were required for its antiproliferative activity in cultured human ASM cells. Proliferation induced by 10% fetal bovine serum (FBS) was abrogated by two unfractionated commercial heparin preparations (Sigma and Multiparin) and this effect was reproduced with each of three low-molecular weight heparin preparations (3, 5 and 6 kDa, respectively), demonstrating that antiproliferative activity resided in at least a 3 kDa heparin fraction. N-desulphated 20% re-acetylated (N-de) heparin (anticoagulant) and O-desulphated heparin (O-de) (non-anticoagulant) fractions also inhibited FBS-dependent proliferation (rank potency: Sigma heparin > O-de > N-de) suggesting that the antiproliferative action of heparin involved N-sulphation but was independent of its anticoagulant activity. Other sulphated molecules with variable anionic charge (dextran sulphate, fucoidan, chondroitin sulphates A or B, heparan sulphate) inhibited proliferation to varying degrees, as did the non-sulphated molecules hyaluronic acid and poly-L-glutamic acid. However, nonsulphated dextran had no effect. In summary, attenuation of FBS-dependent proliferation of human ASM by heparin involves but does not depend upon sulphation, although loss of N-sulphation reduces antiproliferative activity. This antiproliferative effect is independent of anionic charge and the anticoagulant actions of heparin.

Cyclic mechanical strain-induced proliferation and migration of human airway smooth muscle cells: role of EMMPRIN and MMPs

Airway smooth muscle (ASM) proliferation and migration are major components of airway remodeling in asthma. Asthmatic airways are exposed to mechanical strain, which contributes to their remodeling. Matrix metalloproteinase (MMP) plays an important role in remodeling. In the present study, we examined if the mechanical strain of human ASM (HASM) cells contributes to their proliferation and migration and the role of MMPs in this process. HASM were exposed to mechanical strain using the FlexCell system. HASM cell proliferation, migration and MMP release, activation, and expression were assessed. Our results show that cyclic strain increased the proliferation and migration of HASM; cyclic strain increased release and activation of MMP-1, -2, and -3 and membrane type 1-MMP; MMP release was preceded by an increase in extracellular MMP inducer; Prinomastat [a MMP inhibitor (MMPI)] significantly decreased cyclic strain-induced proliferation and migration of HASM; and the strain-induced increase in the release of MMPs was accompanied by an increase in tenascin-C release. In conclusion, cyclic mechanical strain plays an important role in HASM cell proliferation and migration. This increase in proliferation and migration is through an increase in MMP release and activation. Pharmacological MMPIs should be considered in the pursuit of therapeutic options for airway remodeling in asthma.

Ikappa-B kinase-2 inhibitor blocks inflammation in human airway smooth muscle and a rat model of asthma

RATIONALE

Nuclear factor (NF)-kappaB is a transcription factor known to regulate the expression of many inflammatory genes, including cytokines, chemokines, and adhesion molecules. NF-kappaB is held inactive in the cytoplasm, bound to I-kappaB. The removal of I-kappaB, via the actions of inhibitor of kappaB (I-kappaB) kinase-2 (IKK-2), allows NF-kappaB to enter the nucleus.

OBJECTIVES

To determine the impact of inhibiting IKK-2 on in vitro and in vivo models of airway inflammation.

METHODS

The effect of inhibiting IKK-2 was assessed in stimulated, cultured, primary human airway smooth muscle cells and an antigen-driven rat model of lung inflammation.

MEASUREMENTS

The release of cytokines from cultured cells and inflammatory cytokine expression and cellular burden in the lung were determined.

MAIN RESULTS

Two structurally distinct molecules and dominant negative technology demonstrated that inhibition of IKK-2 activity completely blocked cytokine release from cultured cells, whereas the two glucocorticoid comparators had limited impact on granulocyte colony-stimulating factor, interleukin 8, and eotaxin release. In addition, in an in vivo antigen-driven model of airway inflammation, the IKK-2 inhibitor blocked NF-kappaB nuclear translocation, which was associated with a reduction in inflammatory cytokine gene and protein expression, airway eosinophilia, and late asthmatic reaction, similar in magnitude to that obtained with budesonide.

CONCLUSION

This study demonstrates that inhibiting IKK-2 results in a general reduction of the inflammatory response in vitro and in vivo. Compounds of this class could have therapeutic utility in the treatment of asthma and may, in certain respects, possess a beneficial efficacy profile compared with that of a steroid.

Possible pathomechanisms of sudden infant death syndrome: key role of chronic hypoxia, infection/inflammation states, cytokine irregularities, and metabolic trauma in genetically predisposed infants

Chronic hypoxia, viral infections/bacterial toxins, inflammation states, biochemical disorders, and genetic abnormalities are the most likely trigger of sudden infant death syndrome (SIDS). Autopsy studies have shown increased pulmonary density of macrophages and markedly more eosinophils in the lungs accompanied by increased T and B lymphocytes. The elevated levels of immunoglobulins, about 20% more muscle in the pulmonary arteries, increased airway smooth muscle cells, and increased fetal hemoglobin and erythropoietin are evidence of chronic hypoxia before death. Other abnormal findings included mucosal immune stimulation of the tracheal wall, duodenal mucosa, and palatine tonsils, and circulating interferon. Low normal or higher blood levels of cortisol often with petechiae on intrathoracic organs, depleted maternal IgG antibodies to endotoxin core (EndoCAb) and early IgM EndoCAb triggered, partial deletions of the C4 gene, and frequent IL-10-592*A polymorphism in SIDS victims as well as possible hypoxia-induced decreased production of antiinflammatory, antiimmune, and antifibrotic cytokine IL-10, may be responsible for the excessive reactions to otherwise harmless infections. In SIDS infants, during chronic hypoxia and times of infection/inflammation, several proinflammatory cytokines are released in large quantities, sometimes also representing a potential source of tissue damage if their production is not sufficiently well controlled, eg, by pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP). These proinflammatory cytokines down-regulate gene expression of major cytochrome P-450 and/or other enzymes with the specific effects on mRNA levels, protein expression, and enzyme activity, thus affecting metabolism of several endogenous lipophilic substances, such as steroids, lipid-soluble vitamins, prostaglandins, leukotrienes, thromboxanes, and exogenous substances. In SIDS victims, chronic hypoxia, TNF-alpha and other inflammatory cytokines, and arachidonic acid (AA) as well as n-3 polyunsaturated fatty acids (FA), stimulated and/or augmented superoxide generation by polymorphonuclear leukocytes, which contributed to tissue damage. Chronic hypoxia, increased amounts of nonheme iron in the liver and adrenals of these infants, enhanced activity of CYP2C9 regarded as the functional source of reactive oxygen species (ROS) in some endothelial cells, and nicotine accumulation in tissues also intensified production of ROS. These increased quantities of proinflammatory cytokines, ROS, AA, and nitric oxide (NO) also resulted in suppression of many CYP450 and other enzymes, eg, phosphoenolpyruvate carboxykinase (PEPCK), an enzyme important in the metabolism of FA during gluconeogenesis and glyceroneogenesis. PEPCK deficit found in SIDS infants (caused also by vitamin A deficiency) and eventually enhanced by PACAP lipolysis of adipocyte triglycerides resulted in an increased FA level in blood because of their impaired reesterification to triacylglycerol in adipocytes. In turn, the overproduction and release of FA into the blood of SIDS victims could lead to the metabolic syndrome and an early phase of type 2 diabetes. This is probably the reason for the secondary overexpression of the hepatic CYP2C8/9 content and activity reported in SIDS infants, which intensified AA metabolism. Pulmonary edema and petechial hemorrhages often present in SIDS victims may be the result of the vascular leak syndrome caused by IL-2 and IFN-alpha. Chronic hypoxia with the release of proinflammatory mediators IL-1alpha, IL-1beta and IL-6, and overloading of the cardiovascular and respiratory systems due to the narrowing airways and small pulmonary arteries of these children could also contribute to the development of these abnormalities. Moreover, chronic hypoxia of SIDS infants induced also production of hypoxia-inducible factor 1alpha (HIF-1alpha), which stimulated synthesis and release of different growth factors by vascular endothelial cells and intensified subclinical inflammatory reactions in the central nervous system, perhaps potentiated also by PACAP and VIP gene mutations. These processes could lead to the development of brainstem gliosis and disorders in the release of neuromediators important for physiologic sleep regulation. All these changes as well as eventual PACAP abnormalities could result in disturbed homeostatic control of the cardiovascular and respiratory responses of SIDS victims, which, combined with the nicotine effects and metabolic trauma, finally lead to death in these often genetically predisposed children.

Differences in airway remodeling between asthma and chronic obstructive pulmonary disease

The functional consequence of asthma and chronic obstructive pulmonary disease (COPD)is airflow limitation, which is mostly reversible in asthma and not fully reversible in COPD. In both diseases, inflammatory conditions are associated with cellular and structural changes,referred to as remodeling, and these structural changes may lead to thickening of the airway wall, thereby promoting airway narrowing and airflow limitation. However, the pattern of infiltrated cells and the pattern of structural changes occur differently in the two diseases. In asthma, CD4+, T lymphocytes, eosinophils, and mast cells are the predominant cells involved,whereas in COPD, CD8+, T lymphocytes, and macrophages are predominantly involved. In severe cases of asthma and COPD, neutrophil infiltration becomes evident. Regarding structural changes, epithelial injury and early thickening of reticular basement membrane are highly characteristic of the airway wall of asthmatics. Increases in airway smooth muscle mass occur in large airways of severe asthmatics and in small airways of patients with COPD. Thickening of the airway wall, goblet cell hyperplasia, mucous gland hypertrophy, and the luminal obstruction caused by inflammatory exudates and mucous are features of both asthma and COPD. Squamous epithelial metaplasia and airway wall fibrosis are commonly observed characteristics of COPD. Destruction and fibrosis of the alveolar wall occur in COPD but not in asthma. The remodeling processes accompanied by chronic inflammatory infiltrates interact in a complex fashion and contribute to the development of airflow limitation in both asthma and COPD.

Airway remodeling: lessons from animal models

Airway remodeling, an array of persistent tissue structural changes that occurs through a process of injury and dysregulated repair linked to airway chronic inflammation, is presently believed to largely account for the disease mechanisms of asthma. Increases in airway smooth muscle mass are probably the main mechanism causing airway hyperresponsiveness, and changes in the extracellular matrix may stimulate smooth muscle growth and contribute to the mechanics of airway obstruction. The various components of airway remodeling described inhuman asthma have been successfully reproduced in animal models of several species. Most of the data have been contributed by rat models of allergic sensitization and repeated challenge,transgenic mouse models of cytokine overexpression localized to the lung and, more recently, allergen-driven mouse models using wild-type inbred strains. Overall, animal model shave provided significant insights into the mechanisms of airway remodeling and recent technological developments allow us to exploit these models in new directions. However, the challenge of finding new therapeutic strategies that prevent or control airway remodeling,thus providing etiopathogenically oriented treatments for asthma, still stands. Experimental airway remodeling in animals should be an essential tool for treatment discovery in the near future.

Synergistic antiproliferative and apoptotic effects induced by mixed epidermal growth factor receptor inhibitor ZD1839 and nitric oxide donor in human prostatic cancer cell lines

BACKGROUND

The specific inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, ZD1839 induces potent antitumoral effects on several advanced cancer types. The present study was undertaken to determine whether the combination of ZD1839 with an agent donating nitric oxide (NO(*)), sodium nitroprusside (SNP) results in a synergy of anticarcinogenic responses on metastatic prostate cancer (PC) cells.

METHODS

The antiproliferative and apoptotic/necrotic effects of ZD1839 and SNP alone or in combination were estimated on EGF- and serum-stimulated LNCaP, DU145, and PC3 cells by MTT growth tests, trypan blue dye exclusion method, and flow cytometric analyses. Moreover, the cellular ceramide levels were evaluated by the diacylglycerol kinase enzymatic method and the amounts of cytosolic cytochrome c by ELISA assays.

RESULTS

ZD1839 and SNP alone or in combination at lower concentrations induced an inhibition of EGF- and serum-stimulated growth of LNCaP, DU145, and PC3 concomitant with an arrest in the G1 phase of cellular cycle. Interestingly, the mixed ZD1839 and SNP also caused a more substantial apoptotic/necrotic death of these PC cells as compared to drugs alone. Moreover, we have observed that an inhibition of acidic sphingomyelinase, hydrogen peroxide (H(2)O(2)) accumulation and caspase cascades results in a significant reduction of apoptotic/necrotic death induced by mixed ZD1839 and SNP in EGF-stimulated PC3 cells. In addition, the combined ZD1839 plus SNP also induced a higher cellular ceramide and reactive oxygen species (ROS) production, mitochondrial transmembrane potential decrease, and cytochrome c amount released into cytosol as compared to drugs alone.

CONCLUSIONS

The simultaneous use of EGFR inhibitor and compound releasing NO(*) might lead to a synergy in the ceramide and ROS production which might cause cellular membrane damages resulting in a massive apoptotic/necrotic death of metastatic PC cells.

Effects of interleukin-1beta, interleukin-13 and transforming growth factor-beta on gene expression in human airway smooth muscle using gene microarrays

Inflammatory gene expression in airway smooth muscle may be influenced by its inflammatory milieu. We analysed the gene expression profile of airway smooth muscle cells cultured from human airways exposed to a pro-inflammatory cytokine, interleukin-1beta, a T helper-2 cytokine, interleukin-13, and to a growth factor, transforming growth factor (TGF)beta1 (10 ng/ml each) after 4 and 24 h using the Affymetrix GeneChip 95A array which detects approximately 12,500 genes and expression sequence tags (ESTs). Airway smooth muscle cells were responsive to each cytokine with distinctive patterns of gene expression for cytokines, chemokines, adhesion and signalling proteins, and transcription factors. Interleukin-1beta induced the highest number of genes such as cytokines/chemokines including interleukin-8, growth-related oncogene (GRO)-alpha, -beta and -gamma, epithelial neutrophil activating protein (ENA)-78, monocyte chemotactic protein (MCP)-1, -2 and -3 and eotaxin. Using quantitative real-time reverse transcription-polymerase chain reaction, the expression of GRO-alpha, -beta and -gamma, interleukin-8 and eotaxin by interleukin-1beta was confirmed, with good correlation with microarray data. Transforming growth factor (TGF)beta1 induced other growth factors such as connective tissue growth factor (CTGF), vascular endothelial growth factor (VEGF), insulin growth factor (IGF) and many structural and extracellular matrix proteins. Interleukin-13 was the weakest inducer, with stimulation of eotaxin and genes of unknown function. While many genes were co-regulated at 4 and 24 h, there were also differences in expression patterns. Interleukin-1beta induces a predominantly pro-inflammatory profile while TGFbeta1 can be linked to proliferative and matrix changes. The rich profile of mediators, growth factors and signalling molecules released from airway smooth muscle depends on the inflammatory milieu.

DNA Binding To Guide the Development of Tetrahydroindeno[1,2-b]pyrido[4,3,2-de]quinoline Derivatives as Cytotoxic Agents

The tetrahydroindeno[1,2-b]pyrido[4,3,2-de]quinoline chromophore was initially designed as a DNA intercalating unit because of its planar structure. Unexpectedly, one molecule (15d) bearing two N-methylpiperazine chains on both sides of this condensed pentacyclic skeleton fits into the minor groove of DNA and preferentially recognizes AT-rich sequences. The monosubstituted compound 16d was identified as a potent cytotoxic DNA intercalator, whereas the disubstituted analogue 15d represents a new structural motif for the development of DNA sequence-reading small molecules.

Inhibition of chemokine production from human airway smooth muscle cells by fluticasone, budesonide and beclomethasone

Human airway smooth muscle cells (HASMC) contribute to the process of airway wall remodelling in asthma by virtue of their secretory functions. This study was performed to investigate the effectiveness of the commonly used steroids beclomethasone, budesonide and fluticasone in downregulating HASMC production of RANTES and IL-8. HASMC (n=5) were cultured from dissected bronchi using collagenase digestion. Confluent HASMC were exposed to TNFalpha and IL-1beta (10 ng/ml) for 24 h. All stimulations were set with and without pre-treatment with beclomethasone, budesonide or fluticasone for 2 h at concentrations of 10(-9)-10(-6)M. IL-8 and RANTES mRNA expression was assessed by RT-PCR and protein secretion was determined by ELISA. Pre-treatment with beclomethasone, budesonide or fluticasone reduced TNFalpha- and IL-1beta-stimulated IL-8 and RANTES release from HASMC in a dose dependent manner. However, beclomethasone was 22-28% less effective than fluticasone and budesonide in inhibiting chemokine production. TNFalpha- and IL-1beta-induced RANTES and IL-8 expression was reduced on the transcriptional level by pre-treatment with fluticasone and budesonide. The results suggest that the topical steroids fluticasone, budesonide and to a lesser extent beclomethasone may have beneficial effects on airway inflammation in asthma by reducing RANTES and IL-8-induced leukocyte infiltration into the airway wall.

Effects of IL-1beta, TNF-alpha, and macrophage migration inhibitory factor on prostacyclin synthesis in rat pulmonary artery smooth muscle cells

OBJECTIVE

Cytokines have been implicated in the pathophysiology of pulmonary hypertension. We sought to explore the possibility that prostacyclin is a link.

METHODOLOGY

We tested the effects of the cytokines interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha), and macrophage migration inhibitory factor (MIF) on arachidonic acid metabolism of pulmonary artery smooth muscle cells (PASMCs) with special regard to prostacyclin (PGI2) that protects against pulmonary hypertension. Cultured rat PASMCs were treated with IL-1beta, TNF-alpha, or MIF. Expression of prostacyclin synthase (PGIS) and cyclooxygenase-2 (COX-2) mRNAs, and PGI2 synthesis, were measured.

RESULTS

We found that PGIS mRNA expression was suppressed by high concentrations of TNF-alpha and MIF, while COX-2 mRNA was induced by all three cytokines tested. IL-1beta increased PGI2 production in a dose-dependent manner. TNF-alpha and MIF also increased PGI2 production, but to a far lesser degree at high concentrations. TNF-alpha paradoxically decreased PGI2 production at a low concentration.

CONCLUSIONS

These results suggest that TNF-alpha and MIF are potentially antagonistic to the action of PGI2 in rat PASMCs via down-regulation of PGIS mRNA. Simultaneous induction of COX-2 mRNA may further counteract the action of PGI2 by increasing the levels of eicosanoids other than PGI2.

Mitogenic signaling pathways in airway smooth muscle

Increased airway smooth muscle mass has been demonstrated in patients with asthma, bronchopulmonary dysplasia and most recently, cystic fibrosis. These observations emphasize the need for further knowledge of the events involved in airway smooth muscle mitogenesis and hypertrophy. Workers in the field have developed cell culture systems involving tracheal and bronchial myocytes from different species. An emergent body of literature indicates that mutual signal transduction pathways control airway smooth muscle cell cycle entry across species lines. This article reviews what is known about mitogen-activated signal transduction in airway myocytes. The extracellular signal regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI 3-kinase) pathways appear to be key positive regulators of airway smooth muscle mitogenesis; recent studies have also demonstrated specific roles for reactive oxygen and the JAK/STAT pathway. It is also possible that growth factor stimulation of airway smooth muscle concurrently elicits signaling through negative regulatory intermediates such as p38 mitogen-activated protein (MAP) kinase and protein kinase C (PKC) delta, conceivably as a defense against extreme growth.

Platelets are necessary for airway wall remodeling in a murine model of chronic allergic inflammation

Asthma is associated with airway remodeling. Evidence of platelet recruitment to the lungs of asthmatics after allergen exposure suggests platelets participate in various aspects of asthma; although their importance is unknown in the context of airway remodeling, their involvement in atherosclerosis is established. Studies from our laboratory have shown a requirement for platelets in pulmonary leukocyte recruitment in a murine model of allergic lung inflammation. Presently, the effects of platelet depletion and corticosteroid administration on airway remodeling and lung function were examined. Ovalbumin (OVA)-sensitized mice, exposed to aerosolized OVA for 8 weeks, demonstrated epithelial and smooth muscle thickening, and subepithelial reticular fiber deposition in the distal airways. The depletion of platelets via an immunologic (antiplatelet antisera) or nonimmunologic (busulfan) method, markedly reduced airway remodeling. In contrast, dexamethasone administration did not affect epithelial thickening or subepithelial fibrosis, despite significantly inhibiting leukocyte recruitment. Thus, pathways leading to certain aspects of airway remodeling may not depend on leukocyte recruitment, whereas platelet activation is obligatory. OVA-sensitized mice exhibited airway hyperresponsiveness (AHR) compared with sham-sensitized mice following chronic OVA exposure. Neither platelet depletion nor dexamethasone administration inhibited chronic AHR; thus, mechanisms other than inflammation and airway remodeling may be involved in the pathogenesis of chronic AHR.

Synergistic antiproliferative and apoptotic effects induced by epidermal growth factor receptor and protein kinase a inhibitors in human prostatic cancer cell lines

Our results revealed that the blockade of epidermal growth factor receptor (EGFR) tyrosine kinase and protein kinase A (PKA) signaling pathways by specific inhibitors (PD153035 and Rp-cAMPs) leads to a synergistic inhibition of EGF- and serum-stimulated growth of human prostatic cancer cells (LNCaP, DU145 and PC3) concomitant with an arrest in the G1 phase of cellular cycle. Of particular interest, the combination of PD153035 and Rp-cAMPs also caused a more substantial apoptotic/necrotic death of these prostatic cancer cells as compared to drugs alone. Moreover, we observed that the inhibition of acidic sphingomyelinase and caspase cascades results in a marked reduction of DNA fragmentation and apoptotic death induced by PD153035, alone or in combination with Rp-cAMPs, in EGF stimulated PC3 cells. This suggests that these agents might mediate their cytotoxic effects at least in part via the ceramide generation and activation of caspase signaling pathways. N-oleoylethanolamine (OE), an inhibitor of acidic ceramidase, consistently potentiated the apoptotic effects of PD153035 in all the prostatic cancer cell lines tested. Additionally, the cellular ceramide content estimated for PC3 cells was increased after treatment with PD153035, alone or in combination, at a lower dose with OE and Rp-cAMPs. The synergistic apoptotic effect of PD153035 plus Rp-cAMPs induced in PC3 was also accompanied by a significant rate of mitochondrial membrane depolarization and release of cytochrome c into cytosol as compared to drugs alone. Combined, the results indicated that the simultaneous inhibition of EGFR and PKA signaling cascades might lead to a more massive apoptotic death of metastatic prostatic cancer cells by increasing ceramide accumulation and activating of caspase cascade of a mitochondrial dependent manner.