The phosphoinositide 3'-kinase p110δ modulates contractile protein production and IL-6 release in human airway smooth muscle

PI3Kγδ inhibition suppresses key disease features in a rat model of asthma

BACKGROUND

Two isoforms of Phosphoinositide 3-kinase (PI3K), p110γ and p110δ, are predominantly expressed in leukocytes and represent attractive therapeutic targets for the treatment of allergic asthma. The study aim was to assess the impact of administration of an inhaled PI3Kγδ inhibitor (AZD8154) in a rat model of asthma.

METHODS

Firstly, we checked that the tool compound, AZD8154, inhibited rat PI3K γ & δ kinases using rat cell-based assays. Subsequently, a time-course study was conducted in a rat model of asthma to assess PI3K activity in the lung and how it is temporally associated with other key transcription pathways and asthma like features of the model. Finally, the impact on lung dosed AZD8154 on target engagement, pathway specificity, airway inflammation and lung function changes was assessed.

RESULTS

Data showed that AZD8154 could inhibit rat PI3K γ & δ isoforms and, in a rat model of allergic asthma the PI3K pathway was activated in the lung. Intratracheal administration of AZD8154 caused a dose related suppression PI3K pathway activation (reduction in pAkt) and unlike after budesonide treatment, STAT and NF-κB pathways were not affected by AZD8154. The suppression of the PI3K pathway led to a marked inhibition of airway inflammation and reduction in changes in lung function.

CONCLUSION

These data show that a dual PI3Kγδ inhibitor suppress key features of disease in a rat model of asthma to a similar degree as budesonide and indicate that dual PI3Kγδ inhibition may be an effective treatment for people suffering from allergic asthma.

G-protein coupled receptor 34 regulates the proliferation and growth of LS174T cells through differential expression of PI3K subunits and PTEN

Purpose

G-protein coupled receptor (GPR 34) has been found to play important roles in some cancers and regulates the proliferation, apoptosis, and migration of these cancer cells. However, the mechanisms underlying how GPR34 functions to regulate growth and proliferation of colorectal cancer cells remains to be clarified.

Methods

We employed stable GPR34 knockdown LS174T cell models, GPR34 Mab blocking, a CCK-8 kit, and a colony formation assay to characterize the effect of GPR34 on the proliferation of LS174T in vitro and xenograft tumor growth in vivo. The mRNA level of GPR34 was detected by RT-PCR in tumor tissues and adjacent normal tissues from 34 CRC patients.

Results

Based on RT-PCR results, GPR34 exhibited high level in tumor samples compared with adjacent normal samples. Increased expression of GPR34 is more associated with poor prognosis of CRC as shown in The Cancer Genome Atlas (TCGA) dataset by Kaplan–Meier survival analysis. Furthermore, we showed that GPR34 knockdown inhibited the proliferation of LS174T colon cancer cells and related xenograft tumor growth. Searching for the distinct molecular mechanism, we identified several contributors to proliferation of LS174T colon cancer cells: PI3K subunits/PTEN, PDK1/AKT, and Src/Raf/Ras/ERK. GPR34 knockdown inhibited the proliferation of LS174T cells by upregulating expression of PTEN, and downregulating expression of PI3K subunits p110-beta.

Conclusion

Our findings provide direct evidence that GPR34 regulates the proliferation of LS174T cells and the growth of LS174T tumor xenografts by regulating different pathways. High expression of GPR34 mRNA could then be used to predict poor prognosis of CRC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-021-07068-4.

Metal-Stimulated Interleukin-6 Production Through a Proton-Sensing Receptor, Ovarian Cancer G Protein-Coupled Receptor 1, in Human Bronchial Smooth Muscle Cells: A Response Inhibited by Dexamethasone

Purpose

Human bronchial smooth muscle cells (BSMCs) contribute to airway obstruction and hyperresponsiveness in patients with bronchial asthma. BSMCs also generate cytokines and matricellular proteins in response to extracellular acidification through the ovarian cancer G protein-coupled receptor 1 (OGR1). Cobalt (Co) and nickel (Ni) are occupational agents, which cause occupational asthma. We examined the effects of Co and Ni on interleukin-6 (IL-6) secretion by human BSMCs because these metals may act as ligands of OGR1.

Methods

Human BSMCs were incubated in Dulbecco's Modified Eagle Medium (DMEM) containing 0.1% bovine serum albumin (BSA) (0.1% BSA-DMEM) for 16 hours and stimulated for the indicated time by exchanging the medium with 0.1% BSA-DMEM containing any of the metals or pH-adjusted 0.1% BSA-DMEM. IL-6 mRNA expression was quantified via reverse transcription polymerase chain reaction (RT-PCR) using the real-time TaqMan technology. IL-6 was measured using an enzyme-linked immunosorbent assay. Dexamethasone (DEX) was added 30 minutes before each stimulation. To knock down the expression of OGR1 in BSMCs, small interfering RNA (siRNA) targeting OGR1 (OGR1-siRNA) was transfected to the cells and non-targeting siRNA (NT-siRNA) was used as a control.

Results

Co and Ni both significantly increased IL-6 secretion in human BSMCs at 300 μM. This significant increase in IL-6 mRNA expression was observed 5 hours after stimulation. BSMCs transfected with OGR1-siRNA produced less IL-6 than BSMCs transfected with NT-siRNA in response to either Co or Ni stimulation. DEX inhibited Co- and Ni-stimulated IL-6 secretion by human BSMCs as well as pH 6.3-stimulated IL-6 secretion in a dose-dependent manner. DEX did not decrease phosphorylation of ERK1/2, p38 MAP kinase, and NF-κB p65 induced by either Co or Ni stimulation.

Conclusion

Co and Ni induce secretion of IL-6 in human BSMCs through activation of OGR1. Co- and Ni-stimulated IL-6 secretion is inhibited by DEX.

Clinical, Immunological, and Genetic Features in Patients with Activated PI3Kδ Syndrome (APDS): a Systematic Review

Activated phosphoinositide 3-kinase delta syndrome (APDS) is a novel primary immunodeficiency (PID) caused by heterozygous gain of function mutations in PI3Kδ catalytic p110δ (PIK3CD) or regulatory p85α (PIK3R1) subunits leading to APDS1 and APDS2, respectively. Patients with APDS present a spectrum of clinical manifestations, particularly recurrent respiratory infections and lymphoproliferation. We searched PubMed, Web of Science, and Scopus databases for APDS patients and screened for eligibility criteria. A total of 243 APDS patients were identified from 55 articles. For all patients, demographic, clinical, immunologic, and molecular data were collected. Overall, 179 APDS1 and 64 APDS2 patients were identified. The most common clinical manifestations were respiratory tract infections (pneumonia (43.6%), otitis media (28.8%), and sinusitis (25.9%)), lymphoproliferation (70.4%), autoimmunity (28%), enteropathy (26.7%), failure to thrive (20.6%), and malignancy (12.8%). The predominant immunologic phenotype was hyper-IgM syndrome (48.1%). Immunologic profiling showed decreased B cells in 74.8% and CD4⁺ T cells in 64.8% of APDS patients. The c.3061 G>A (p. E1021K) mutation in APDS1 with 85% frequency and c.1425+1 G> (A, C, T) (p.434-475del) mutation in APDS2 with 79% frequency were hotspot mutations. The majority of APDS patients were placed on long-term immunoglobulin replacement therapy. Immunosuppressive agents such as rituximab, tacrolimus, rapamycin, and leniolisib were also administered for autoimmunity and inflammatory complications. In addition, hematopoietic stem cell transplantation (HSCT) was used in 12.8% of patients. APDS has heterogynous clinical manifestations. It should be suspected in patients with history of recurrent respiratory infections, lymphoproliferation, and raised IgM levels. Moreover, HSCT should be considered in patients with severe and complicated clinical manifestations with no or insufficient response to the conventional therapies.

PI3K signalling in chronic obstructive pulmonary disease and opportunities for therapy

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterised by airway inflammation and progressive obstruction of the lung airflow. Current pharmacological treatments include bronchodilators, alone or in combination with steroids, or other anti-inflammatory agents, which have only partially contributed to the inhibition of disease progression and mortality. Therefore, further research unravelling the underlying mechanisms is necessary to develop new anti-COPD drugs with both lower toxicity and higher efficacy. Extrinsic signalling pathways play crucial roles in COPD development and exacerbations. In particular, phosphoinositide 3-kinase (PI3K) signalling has recently been shown to be a major driver of the COPD phenotype. Therefore, several small-molecule inhibitors have been identified to block the hyperactivation of this signalling pathway in COPD patients, many of them showing promising outcomes in both preclinical animal models of COPD and human clinical trials. In this review, we discuss the critically important roles played by hyperactivated PI3K signalling in the pathogenesis of COPD. We also critically review current therapeutics based on PI3K inhibition, and provide suggestions focusing on PI3K signalling for the further improvement of the COPD phenotype. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

p55PIK deficiency and its NH2-terminal derivative inhibit inflammation and emphysema in COPD mouse model

Chronic obstructive pulmonary disease (COPD) is composed of chronic airway inflammation and emphysema. Recent studies show that Class IA phosphatidylinositol 3-kinases (PI3Ks) play an important role in the regulation of inflammation and emphysema. However, there are few studies on their regulatory subunits. p55PIK is a regulatory subunit of Class IA PI3Ks, and its unique NH₂-terminal gives it special functions. p55PIK expression in the lungs of nonsmokers, smokers, and patients with COPD was examined. We established a fusion protein TAT-N15 from the NH₂-terminal effector sequence of p55PIK and TAT (the transduction domain of HIV transactivator protein) and investigated the effects of silencing p55PIK or adding TAT-N15 on cigarette smoke exposure at the cellular and animal level. p55PIK expression was increased in patients with COPD. p55PIK deficiency and TAT-N15 significantly inhibited the cigarette smoke extract-induced IL-6, IL-8, and activation of the Akt and the NF-κB pathway in BEAS-2B. p55PIK deficiency and TAT-N15 intranasal administration prevented emphysema and the lung function decline in mice exposed to smoke for 6 mo. p55PIK deficiency and TAT-N15 significantly inhibited lung inflammatory infiltration, reduced levels of IL-6 and KC in mice lung homogenate, and inhibited activation of the Akt and the NF-κB signaling in COPD mice lungs. Our studies indicate that p55PIK is involved in the pathogenesis of COPD, and its NH₂-terminal derivative TAT-N15 could be an effective drug in the treatment of COPD by inhibiting the activation of the Akt and the NF-κB pathway.

Transforming Growth Factor-β1 Decreases β2-Agonist-induced Relaxation in Human Airway Smooth Muscle

Helper T effector cytokines implicated in asthma modulate the contractility of human airway smooth muscle (HASM) cells. We have reported recently that a profibrotic cytokine, transforming growth factor (TGF)-β1, induces HASM cell shortening and airway hyperresponsiveness. Here, we assessed whether TGF-β1 affects the ability of HASM cells to relax in response to β₂-agonists, a mainstay treatment for airway hyperresponsiveness in asthma. Overnight TGF-β1 treatment significantly impaired isoproterenol (ISO)-induced relaxation of carbachol-stimulated, isolated HASM cells. This single-cell mechanical hyporesponsiveness to ISO was corroborated by sustained increases in myosin light chain phosphorylation. In TGF-β1-treated HASM cells, ISO evoked markedly lower levels of intracellular cAMP. These attenuated cAMP levels were, in turn, restored with pharmacological and siRNA inhibition of phosphodiesterase 4 and Smad3, respectively. Most strikingly, TGF-β1 selectively induced phosphodiesterase 4D gene expression in HASM cells in a Smad2/3-dependent manner. Together, these data suggest that TGF-β1 decreases HASM cell β₂-agonist relaxation responses by modulating intracellular cAMP levels via a Smad2/3-dependent mechanism. Our findings further define the mechanisms underlying β₂-agonist hyporesponsiveness in asthma, and suggest TGF-β1 as a potential therapeutic target to decrease asthma exacerbations in severe and treatment-resistant asthma.

Inhibition of PI3Kδ Enhances Poly I:C-Induced Antiviral Responses and Inhibits Replication of Human Metapneumovirus in Murine Lungs and Human Bronchial Epithelial Cells

Viral infections of the airway can exacerbate respiratory diseases, such as asthma or chronic obstructive pulmonary disease (COPD), and accelerate disease progression. Phosphoinositide 3-kinase (PI3K)δ, a class 1A PI3K, has been studied as a potential target for achieving anti-oncogenic and anti-inflammatory effects. However, the role of PI3Kδ in antiviral responses is poorly understood. Using a synthetic double-stranded RNA poly I:C and a selective PI3Kδ inhibitor IC87114, we investigated the role of PI3Kδ signaling in poly I:C-induced expression of the T lymphocyte-inhibitory molecule programmed death 1 ligand 1 (PD-L1), inflammatory responses and antiviral interferon (IFN) responses. C57BL/6N mice were treated with IC87114 or vehicle by intratracheal (i.t.) instillation followed by i.t. administration of poly I:C. Poly I:C increased PD-L1 expression on epithelial cells, lymphocytes, macrophages, and neutrophils in the lungs and IC87114 suppressed poly I:C-induced PD-L1 expression on epithelial cells and neutrophils possibly via inhibition of the Akt/mTOR signaling pathway. IC87114 also attenuated poly I:C-induced increases in numbers of total cells, macrophages, neutrophils and lymphocytes, as well as levels of KC, IL-6 and MIP-1β in bronchoalveolar lavage fluid. Gene expression of IFNβ, IFNλ₂ and IFN-stimulated genes (ISGs) were upregulated in response to poly I:C and a further increase in gene expression was observed following IC87114 treatment. In addition, IC87114 enhanced poly I:C-induced phosphorylation of IRF3. We assessed the effects of IC87114 on human primary bronchial epithelial cells (PBECs). IC87114 decreased poly I:C-induced PD-L1 expression on PBECs and secretion of IL-6 and IL-8 into culture supernatants. IC87114 further enhanced poly I:C- induced increases in the concentrations of IFNβ and IFNλ_1/3 in culture supernatants as well as upregulated gene expression of ISGs in PBECs. Similar results were obtained in PBECs transfected with siRNA targeting the PIK3CD gene encoding PI3K p110δ, and stimulated with poly I:C. In human metapneumovirus (hMPV) infection of PBECs, IC87114 suppressed hMPV-induced PD-L1 expression and reduced viral replication without changing the production levels of IFNβ and IFNλ_1/3 in culture supernatants. These data suggest that IC87114 may promote virus elimination and clearance through PD-L1 downregulation and enhanced antiviral IFN responses, preventing prolonged lung inflammation, which exacerbates asthma and COPD.

Placenta-Derived Mesenchymal Stem Cells Reduce the Interleukin-5 Level Experimentally in Children with Asthma

Background: Mesenchymal stem cells (MSCs) have been investigated as a new treatment option for various diseases in recent years. However, the role of placenta-derived MSCs in children with asthma remains unclear. We assessed the effect of placenta-derived MSCs on T cell immune responses and cytokine IL-5 levels according to cultures in children with and without asthma. Study design: We enrolled children with and without asthma and recorded asthma symptom scores in the asthma group. Blood samples from children were collected to isolate peripheral blood mononuclear cells (PBMCs) and determine the total IgE level. The PBMCs were cultured in vitro with or without MSCs after stimulation with human anti-CD3 and anti-CD28 antibodies (0.5 μg/mL) to evaluate the effect of placenta-derived MSCs. Flow cytometry was performed to detect the activation and proliferation of CD4+ and CD8+ T cells. Pre- and post-culture IL-5 levels were measured in all samples. Results: The percentages of activation and proliferation among CD4+ and CD8+ T cells after coculture with MSCs were significantly lower in the asthma group (P < 0.05). IL-5 levels differed significantly between the PBMC culture and PBMC + MSC (P+S) coculture in the asthma group (P < 0.05). IL-5 levels differed significantly between the PBMC culture and P+S coculture in both the lower (P < 0.05) and higher (P < 0.0005) IgE asthma subgroups. IL-5 levels were also decreased in children with all severities of asthma (P < 0.05). Conclusions: Placenta-derived MSCs exerted an anti-IL-5 effect and reduced the IL-5 level in culture in different subgroups of children with asthma.

Phosphoinositide 3-kinase δ (PI3Kδ) in respiratory disease

Defining features of chronic airway diseases include abnormal and persistent inflammatory processes, impaired airway epithelial integrity and function, and increased susceptibility to recurrent respiratory infections. Phosphoinositide 3-kinases (PI3K) are lipid kinases, which contribute to multiple physiological and pathological processes within the airway, with abnormal PI3K signalling contributing to the pathogenesis of several respiratory diseases. Consequently, the potential benefit of targeting PI3K isoforms has received considerable attention, being viewed as a viable therapeutic option in inflammatory and infectious lung disorders. The class I PI3K isoform, PI3Kδ (Phosphoinositide 3-kinases δ) is of particular interest given its multiple roles in modulating innate and adaptive immune cell functions, airway inflammation and corticosteroid sensitivity. In this mini-review, we explore the role of PI3Kδ in airway inflammation and infection, focusing on oxidative stress, ER stress, histone deacetylase 2 and neutrophil function. We also describe the importance of PI3Kδ in adaptive immune cell function, as highlighted by the recently described Activated PI3K Delta Syndrome, and draw attention to some of the potential clinical applications and benefits of targeting this molecule.

Phosphoinositide 3-Kinase in Asthma: Novel Roles and Therapeutic Approaches

Asthma manifests as airway hyperresponsiveness and inflammation, including coughing, wheezing, and shortness of breath. Immune cells and airway structural cells orchestrate asthma pathophysiology, leading to mucus secretion, airway narrowing, and obstruction. Phosphoinositide 3-kinase, a lipid kinase, plays a crucial role in many of the cellular and molecular mechanisms driving asthma pathophysiology and represents an attractive therapeutic target. Here, we summarize the diverse roles of phosphoinositide 3-kinase in the pathogenesis of asthma and discuss novel therapeutic approaches to treatment.

Transforming Growth Factor β1 Function in Airway Remodeling and Hyperresponsiveness. The Missing Link?

The pathogenesis of asthma includes a complex interplay among airway inflammation, hyperresponsiveness, and remodeling. Current evidence suggests that airway structural cells, including bronchial smooth muscle cells, myofibroblasts, fibroblasts, and epithelial cells, mediate all three aspects of asthma pathogenesis. Although studies show a connection between airway remodeling and changes in bronchomotor tone, the relationship between the two remains unclear. Transforming growth factor β1 (TGF-β1), a growth factor elevated in the airway of patients with asthma, plays a role in airway remodeling and in the shortening of various airway structural cells. However, the role of TGF-β1 in mediating airway hyperresponsiveness remains unclear. In this review, we summarize the literature addressing the role of TGF-β1 in airway remodeling and shortening. Through our review, we aim to further elucidate the role of TGF-β1 in asthma pathogenesis and the link between airway remodeling and airway hyperresponsiveness in asthma and to define TGF-β1 as a potential therapeutic target for reducing asthma morbidity and mortality.

Effect of TGF-β1 on the Migration and Recruitment of Mesenchymal Stem Cells after Vascular Balloon Injury: Involvement of Matrix Metalloproteinase-14

Restenosis or occlusion after vascular procedures is ascribed to intimal hyperplasia. Transforming growth factor (TGF)-β1 is involved in recruitment of mesenchymal stem cells (MSCs) following arterial injury, and its release from latent TGF-binding protein by matrix metalloproteinase (MMP)-14-induced proteolysis contributes to neointima formation. However, the relationship between MMP-14 and TGF-β1 activation in restenosis is unknown. This study investigated the relationship using a rat model of balloon-induced injury. Rats were assigned to vehicle-, SB431542 (SB)-, or recombinant human (rh)TGF-β1-treated groups and examined at various time points after balloon-induced injury for expression of TGF-β1/Smad signalling pathway components, MMP-14 and MSCs markers including Nestin, CD29, and Sca1⁺CD29⁺CD11b/c⁻CD45⁻. Intimal hyperplasia was reduced in SB- and rhTGF-β1-treated rats. The expression of TGF-β1, TGF-β1RI, and Smad2/3 was decreased, but the levels of phosphorylated Smad2/3 were higher in SB-treated rats than vehicle-treated after 7 days to 14 days. rhTGF-β1 administration decreased the expression of TGF-β1/Smad pathway proteins, except for TGF-β1RI. Nestin and CD29 expression and the number of Sca1⁺CD29⁺CD11b⁻CD45⁻ cells were reduced, whereas MMP-14 expression was increased after SB431542 and rhTGF-β1 administration. These results suggest that TGF-β1/Smad signalling and MMP-14 act to recruit MSCs which differentiate to vascular smooth muscle cells and mesenchymal-like cells that participate in arterial repair/remodelling.

Novel drug targets for asthma and COPD: lessons learned from in vitro and in vivo models

Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent respiratory diseases characterized by airway inflammation, airway obstruction and airway hyperresponsiveness. Whilst current therapies, such as β-agonists and glucocorticoids, may be effective at reducing symptoms, they do not reduce disease progression. Thus, there is a need to identify new therapeutic targets. In this review, we summarize the potential of novel targets or tools, including anti-inflammatories, phosphodiesterase inhibitors, kinase inhibitors, transient receptor potential channels, vitamin D and protease inhibitors, for the treatment of asthma and COPD.

PI3K-δ and PI3K-γ inhibition by IPI-145 abrogates immune responses and suppresses activity in autoimmune and inflammatory disease models

Phosphoinositide-3 kinase (PI3K)-δ and PI3K-γ are preferentially expressed in immune cells, and inhibitors targeting these isoforms are hypothesized to have anti-inflammatory activity by affecting the adaptive and innate immune response. We report on a potent oral PI3K-δ and PI3K-γ inhibitor (IPI-145) and characterize this compound in biochemical, cellular, and in vivo assays. These studies demonstrate that IPI-145 exerts profound effects on adaptive and innate immunity by inhibiting B and T cell proliferation, blocking neutrophil migration, and inhibiting basophil activation. We explored the therapeutic value of combined PI3K-δ and PI3K-γ blockade, and IPI-145 showed potent activity in collagen-induced arthritis, ovalbumin-induced asthma, and systemic lupus erythematosus rodent models. These findings support the hypothesis that inhibition of immune function can be achieved through PI3K-δ and PI3K-γ blockade, potentially leading to significant therapeutic effects in multiple inflammatory, autoimmune, and hematologic diseases.

EGF-induced bronchial epithelial cells drive neutrophil chemotactic and anti-apoptotic activity in asthma

Chronic damage and repair of the bronchial epithelium are features of asthma. We have previously reported that ex vivo stimulation of normal bronchial epithelial cells with epidermal growth factor (EGF), a key factor of epithelial repair, enhances the mechanisms of neutrophil accumulation, thereby promoting neutrophil defences during acute injury but potentially enhancing inflammation in chronic airway diseases. We have now sought to (i) determine whether this EGF-dependent pro-neutrophil activity is increased in asthma, where EGF and its epithelial receptor are over-expressed, and (ii) elucidate some of the mechanisms underlying this asthmatic epithelial-neutrophil interaction. Primary bronchial epithelial cells (PBEC) from healthy subjects, mild asthmatics and moderate-to-severe asthmatics (Mod/Sev) were stimulated with EGF, a model that mimics a repairing epithelium. Conditioned culture media (EGF-CM) were assessed for neutrophil chemotactic and anti-apoptotic activities and inflammatory mediator production. EGF induced the epithelium to produce soluble mediators with neutrophil chemotactic (p<0.001) and pro-survival (p = 0.021) activities which were related to the clinical severity of asthma (trend p = 0.010 and p = 0.009, respectively). This was associated with enhanced IL-6, IL-8, GM-CSF and TNF-α release, and cytokine-neutralising experiments using EGF-CM from Mod/Sev asthmatics demonstrated a role for GM-CSF in neutrophil survival (p<0.001). Pre-treatment of neutrophils with specific inhibitors of the myeloid-restricted class I phosphatidylinositol-3-OH kinase (PI(3)K) isoforms showed that the EGF-CM from Mod/Sev asthmatics depended on the γ (p<0.021) but not δ isoforms, while neutrophil survival required multiple class I PI(3)Ks. The EGF-induced chemotactic, but not pro-survival activity, involved RhoA signaling in neutrophils (p = 0.012). EGF whose activity is upregulated in asthma induces ex vivo the epithelium from asthmatic patients to produce pro-neutrophil activities; these are related to asthma severity and, in moderate-to-severe asthmatics, involves class IB PI(3)Kγ signaling, providing a potential therapeutic target for neutrophilic forms of asthma.

Simultaneous quantitation of IC87114, roflumilast and its active metabolite roflumilast N-oxide in plasma by LC-MS/MS: application for a pharmacokinetic study

A sensitive and reliable high-performance liquid chromatography-mass spectrometry (LC-MS/MS) was developed and validated for simultaneous quantification IC87114, roflumilast (RFM), and its active metabolite roflumilast N-oxide (RFN) using tolbutamide as an internal standard. The analytes were extracted by using liquid-liquid extraction and separated on a reverse phase C(18) column (50 mm × 3 mm i.d., 4.6 µ) using methanol: 2 mM ammonium acetate buffer, pH 4.0 as mobile phase at a flow rate 1 mL/min in gradient mode. Selective reaction monitoring was performed using the transitions m/z 398.3 > 145.9, 403.1 >186.9, 419.1 > 187.0 and 271.1 > 155.0 to quantify quantification IC87114, RFM, RFN and tolbutamide, respectively. The method was validated over the concentration range of 0.1-60 ng.mL(-1) for RFM and RFN and 6 to 2980 ng.mL(-1) for IC87114. Intra- and inter-day accuracy and precision of validated method were within the acceptable limits of <15% at all concentrations. Coefficients of correlation (r(2) ) for the calibration curves were >0.99 for all analytes. The quantitation method was successfully applied for simultaneous estimation of IC87114, RFM and RFN in a pharmacokinetic drug-drug interaction study in Wistar rats.

Thiazolidinediones inhibit airway smooth muscle release of the chemokine CXCL10: in vitro comparison with current asthma therapies

BACKGROUND

Activated mast cells are present within airway smooth muscle (ASM) bundles in eosinophilic asthma. ASM production of the chemokine CXCL10 plays a role in their recruitment. Thus the effects of glucocorticoids (fluticasone, budesonide), long-acting β2-agonists (salmeterol, formoterol) and thiazolidinediones (ciglitazone, rosiglitazone) on CXCL10 production by ASM cells (ASMC) from people with and without asthma were investigated in vitro.

METHODS

Confluent serum-deprived cells were treated with the agents before and during cytokine stimulation for 0-24 h. CXCL10 protein/mRNA, IκB-α levels and p65 activity were measured using ELISA, RT PCR, immunoblotting and p65 activity assays respectively. Data were analysed using ANOVA followed by Fisher's post-hoc test.

RESULTS

Fluticasone and/or salmeterol at 1 and 100 nM inhibited CXCL10 release induced by IL-1β and TNF-α, but not IFNγ or all three cytokines (cytomix). The latter was also not affected by budesonide and formoterol. In asthmatic ASMC low salmeterol, but not formoterol, concentrations increased cytomix-induced CXCL10 release and at 0.01 nM enhanced NF-κB activity. Salmeterol 0.1 nM together with fluticasone 0.1 and 10 nM still increased CXCL10 release. The thiazolidinediones ciglitazone and rosiglitazone (at 25 and 100 μM) inhibited cytomix-induced CXCL10 release but these inhibitory effects were not prevented by the PPAR-g antagonist GW9662. Ciglitazone did not affect early NF-κB activity and CXCL10 mRNA production.

CONCLUSIONS

Thus the thiazolidinediones inhibited asthmatic ASMC CXCL10 release under conditions when common asthma therapies were ineffective or enhanced it. They may provide an alternative strategy to reduce mast cell-ASM interactions and restore normal airway physiology in asthma.

Emerging airway smooth muscle targets to treat asthma

Asthma is characterized in part by variable airflow obstruction and non-specific hyperresponsiveness to a variety of bronchoconstrictors, both of which are mediated by the airway smooth muscle (ASM). The ASM is also involved in the airway inflammation and airway wall remodeling observed in asthma. For all these reasons, the ASM provides an important target for the treatment of asthma. Several classes of drugs were developed decades ago which targeted the ASM - including β-agonists, anti-cholinergics, anti-histamines and anti-leukotrienes - but no substantially new class of drug has appeared recently. In this review, we summarize the on-going work of several laboratories aimed at producing novel targets and/or tools for the treatment of asthma. These range from receptors and ion channels on the ASM plasmalemma, to intracellular effectors (particularly those related to cyclic nucleotide signaling, calcium-homeostasis and phosphorylation cascades), to anti-IgE therapy and outright destruction of the ASM itself.

Regulation of CD38 expression in human airway smooth muscle cells: role of class I phosphatidylinositol 3 kinases

The ADP-ribosyl cyclase activity of CD38 generates cyclic ADP-ribose, a Ca(2+)-mobilizing agent. In human airway smooth muscle (HASM) cells, TNF-α mediates CD38 expression through mitogen-activated protein kinases and NF-κB and AP-1. The phosphatidylinositol-3 kinase/Akt (PI3K/Akt) pathway is involved in TNF-α signaling and contributes to airway hyperresponsiveness and airway remodeling. We hypothesized that PI3Ks mediate CD38 expression and are involved in the differential induction of CD38 by TNF-α in asthmatic HASM cells. HASM cells were treated with pan-PI3K inhibitors (LY294002 or wortmannin) or class I-selective (GDC0941) or isoform-selective PI3K inhibitors (p110α-PIK-75 and p110β-TGX-221) with or without TNF-α. HASM cells were transfected with a catalytically active form of PI3K or phosphatase and tensin homolog (PTEN) or nontargeting or p110 isoform-targeting siRNAs before TNF-α exposure. CD38 expression and activation of Akt, NF-κB, and AP-1 were determined. LY294002 and wortmannin inhibited TNF-α-induced Akt activation, whereas only LY294002 inhibited CD38 expression. P110 expression caused Akt activation and basal and TNF-α-induced CD38 expression, whereas PTEN expression attenuated Akt activation and CD38 expression. Expression levels of p110 isoforms α, β, and δ were comparable in nonasthmatic and asthmatic HASM cells. Silencing of p110α or -δ, but not p110β, resulted in comparable attenuation of TNF-α-induced CD38 expression in asthmatic and nonasthmatic cells. NF-κB and AP-1 activation were unaltered by the PI3K inhibitors. In HASM cells, regulation of CD38 expression occurs by specific class I PI3K isoforms, independent of NF-κB or AP-1 activation, and PI3K signaling may not be involved in the differential elevation of CD38 in asthmatic HASM cells.