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Pradère P, Garcia G, Humbert M, Aubier M, Taillé C. [Omalizumab: What have we learned after ten years of prescription?]. Rev Mal Respir 2015; 33:117-27. [PMID: 26346415 DOI: 10.1016/j.rmr.2015.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/26/2015] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Omalizumab, an anti-immunoglobulin E monoclonal antibody, has now been used for ten years as an add-on therapy for severe adult atopic asthma, poorly controlled by high-doses inhaled steroids and long-acting beta-agonists. BACKGROUND This innovative therapy has been the first biotherapy used on a large scale in severe asthma. It has shown clinical benefits, especially in the prevention of severe exacerbation, with a satisfactory safety profile. Despite its cost, it is an interesting alternative to continuous oral steroids, which cause more long-term side effects. PERSPECTIVES After ten-years of prescription of omalizumab, we review here the mechanism of action, the benefits, the main side effects, the cost-effectiveness and also the alternative indications of this interesting molecule. We also consider the practicalities of using omalizumab, particularly the importance a rigorous assessment of its efficacy after 16 weeks of treatment, and possible future therapeutic indications. CONCLUSION Omalizumab has proven its efficacy in large randomized studies but also in real life practice in severe allergic asthma.
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Affiliation(s)
- P Pradère
- Service de pneumologie, centre de compétence pour les maladies pulmonaires rares, université Paris Diderot, hôpital Bichat, AP-HP, 46, rue Henri-Huchard, 75877 Paris cedex 18, France
| | - G Garcia
- Service de pneumologie, université Paris-Sud, hôpital de Bicêtre, AP-HP, 94270 Le Kremlin-Bicêtre, France
| | - M Humbert
- Service de pneumologie, université Paris-Sud, hôpital de Bicêtre, AP-HP, 94270 Le Kremlin-Bicêtre, France
| | - M Aubier
- Service de pneumologie, centre de compétence pour les maladies pulmonaires rares, université Paris Diderot, hôpital Bichat, AP-HP, 46, rue Henri-Huchard, 75877 Paris cedex 18, France
| | - C Taillé
- Service de pneumologie, centre de compétence pour les maladies pulmonaires rares, université Paris Diderot, hôpital Bichat, AP-HP, 46, rue Henri-Huchard, 75877 Paris cedex 18, France.
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Roth M, Zhao F, Zhong J, Lardinois D, Tamm M. Serum IgE Induced Airway Smooth Muscle Cell Remodeling Is Independent of Allergens and Is Prevented by Omalizumab. PLoS One 2015; 10:e0136549. [PMID: 26332463 PMCID: PMC4557956 DOI: 10.1371/journal.pone.0136549] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/04/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Airway wall remodeling in allergic asthma is reduced after treatment with humanized anti-IgE-antibodies. We reported earlier that purified IgE, without the presence of allergens, is sufficient to induce airway wall remodeling due to airway smooth muscle cell (ASMC) activity deposing extracellular matrix. OBJECTIVE We postulate that IgE contained in serum of allergic asthma patients, in the absence of allergens, stimulates ASMC remodeling activities and can be prevented by anti-IgE antibodies. METHODS Isolated human ASMC were exposed to serum obtained from: (i) healthy controls, or patients with (ii) allergic asthma, (iii) non-allergic asthma, and (iv) atopic non-asthma patients. Proliferation and the deposition of collagens and fibronectin were determined after 3 and 5 days. RESULTS Serum from patients with allergies significantly stimulated: (i) ASMC proliferation, (ii) deposition of collagen type-I (48 hours) and (iii) of fibronectin (24 hours). One hour pre-incubation with Omalizumab prevented these three effects of allergic serum, but had no significant effect on serum from healthy donors or non-allergic asthma patients. Interestingly, the addition of allergens did not further increase any of the IgE effects. CONCLUSION AND CLINICAL RELEVANCE Our data provides experimental evidence that the beneficial effect of Omalizumab on airway wall remodeling and improved lung function may be due to its direct action on IgE bound ASMC.
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Affiliation(s)
- Michael Roth
- Pulmonary Cell Research, Department Biomedicine, University Basel, Basel, Switzerland
- Department Internal Medicine, Pneumology, University Hospital Basel, Basel, Switzerland
- * E-mail:
| | - Feng Zhao
- Pulmonary Cell Research, Department Biomedicine, University Basel, Basel, Switzerland
- Department of Respiratory Diseases, Xijing Hospital, 4th Military Medical University, Xi’an, People’s Republic of China
| | - Jun Zhong
- Pulmonary Cell Research, Department Biomedicine, University Basel, Basel, Switzerland
| | - Didier Lardinois
- Department Thoracic Surgery, University Hospital Basel, Basel, Switzerland
| | - Michael Tamm
- Department Internal Medicine, Pneumology, University Hospital Basel, Basel, Switzerland
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Abstract
Asthma remains a major health problem with significant morbidity, mortality and economic costs. In asthma, airway remodelling, which refers to all the microscopic structural changes seen in the airway tissue, has been recognised for many decades and remains one of the defining characteristics of the disease; however, it is still poorly understood. The detrimental pathophysiological consequences of some features of remodelling, like increased airway smooth muscle mass and subepithelial fibrosis, are well documented. However, whether targeting these by therapy would be beneficial is unknown. Although the prevailing thinking is that remodelling is an abnormal response to persistent airway inflammation, recent evidence, especially from studies of remodelling in asthmatic children, suggests that the two processes occur in parallel. The effects of asthma therapy on airway remodelling have not been studied extensively due to the challenges of obtaining airway tissue in the context of clinical trials. Corticosteroids remain the cornerstone of asthma therapy, and their effects on remodelling have been better studied than other drugs. Bronchial thermoplasty is the only asthma therapy to primarily target remodelling, although how it results in the apparent clinical benefits seen is not exactly clear. In this article we discuss the mechanisms of airway remodelling in asthma and review the effects of conventional and novel asthma therapies on the process.
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Affiliation(s)
- Rachid Berair
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, Glenfield Hospital, University of Leicester, Leicester, LE3 9QP, UK
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Licari A, Marseglia G, Castagnoli R, Marseglia A, Ciprandi G. The discovery and development of omalizumab for the treatment of asthma. Expert Opin Drug Discov 2015; 10:1033-42. [PMID: 25979110 DOI: 10.1517/17460441.2015.1048220] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION The evolution in immunological methods used to assess human allergic diseases has led to the identification of immunoglobulin E (IgE) as a diagnostic biomarker and a potential therapeutic target. Innovative technologies in molecular biology and immunogenetics contributed to the development of a selective blocking agent, disclosing new therapeutic perspectives in the treatment of allergic asthma. Omalizumab is the most advanced humanized anti-IgE monoclonal antibody that specifically binds serum-free IgE. Omalizumab also interrupts the allergic cascade by preventing binding of IgE with FcεRI receptors on mast cells, basophils, antigen-presenting cells and other inflammatory cells. AREAS COVERED This review discusses the discovery strategy and preclinical development of omalizumab. Furthermore, it also provides a clinical overview of the key trials leading to its launch and a detailed analysis of safety and post-marketing data. EXPERT OPINION The clinical efficacy of omalizumab in allergic asthma has been well documented in clinical trials, involving adults, adolescents and children with moderate-to-severe and severe allergic asthma. To date, omalizumab has also been approved in chronic idiopathic urticaria for patients 12 years and older who remain symptomatic despite high dosages of H1 antihistamines. Omalizumab has also been investigated in many other different patient populations beyond allergic asthma and may yet have an application to other indications. While omalizumab is the only mAb available for treating allergic asthma, the authors anticipate that new mAbs will emerge in the future that overcome omalizumab's current limitations.
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Affiliation(s)
- Amelia Licari
- University of Pavia, Foundation IRCCS Policlinico San Matteo, Department of Pediatrics , Pavia , Italy
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Pałgan K, Bartuzi Z. Angiogenesis in bronchial asthma. Int J Immunopathol Pharmacol 2015; 28:415-20. [PMID: 25875602 DOI: 10.1177/0394632015580907] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 03/16/2015] [Indexed: 12/14/2022] Open
Abstract
Bronchial asthma is a chronic inflammatory disease characterised by airflow obstruction that may be reversed spontaneously or in response to treatment. The airway inflammation can lead to structural changes and remodelling consisting of subepithelial layer thickening, airway smooth muscle hyperplasia and angiogenesis. Subepithelial hypervascularity and angiogenesis in the airways are part of the structural airway wall in asthma. Increased vascularity of bronchial mucosa is closely related to the expression of angiogenic factors like vascular endothelial growth factor (VEGF), angiopoietin and hypoxia-inducible factor (HIF). The scope of the present review is to summarise the roles of anagiogenic factors and treatment in vascular development.
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Affiliation(s)
- Krzysztof Pałgan
- Department of Allergology, Clinical Immunology and Internal Medicine, Collegium Medicum Bydgoszcz, Nicolaus Copernicus University of Toruń, Poland
| | - Zbigniew Bartuzi
- Department of Allergology, Clinical Immunology and Internal Medicine, Collegium Medicum Bydgoszcz, Nicolaus Copernicus University of Toruń, Poland
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Prolonged Treatment with Inhaled Corticosteroids does not Normalize High Activity of Matrix Metalloproteinase-9 in Exhaled Breath Condensates of Children with Asthma. Arch Immunol Ther Exp (Warsz) 2015; 63:231-7. [PMID: 25650123 PMCID: PMC4429133 DOI: 10.1007/s00005-015-0328-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 01/17/2015] [Indexed: 10/31/2022]
Abstract
The airway remodeling in asthma is associated with increased amount of matrix metalloproteinase (MMP)-9. High levels of MMP-9 were found in mucosal biopsies, sputum and in exhaled breath condensates (EBC) of asthma patients. However, there are no data concerning real in vivo activity. Inhaled corticosteroids are effective in asthma control, but it is unclear, whether they only attenuate inflammation, or also protect against progressive remodeling of respiratory tract. Therefore, the aim of the study was to assess the amount and activity of MMP-9 in context of pro-inflammatory cytokines (IL-6, IL-8 and tumor necrosis factor, TNF), measured in EBC of asthma-suffering children, treated with inhaled steroids. The study involved 27 children with asthma, continuously treated with inhaled fluticasone propionate, and 22 healthy controls. In addition to routine clinical screening, the selected cytokines in EBC were analyzed using Ultrasensitive ELISA, whereas activity of MMP-9 was assessed using a novel immunozymography method. Despite chronic treatment with inhaled steroids mean MMP-9/EBC activity in asthma group was significantly higher than in healthy controls. Moreover, high MMP-9/EBC in asthma-suffering children significantly correlated with IgE serum levels. The IL-6 and IL-8 concentration was below the detection limit in all EBC samples. TNF/EBC levels were similar in both, asthma and healthy children. We hypothesize that MMP-9 hyperactivity in asthma may be closely related to high IgE serum levels. Our results suggest that inhaled steroids may be ineffective to prevent asthma-associated airway remodeling. Finally, we emphasize the necessity of further research focused on MMP-9 inhibition in asthma treatment.
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Ahn KB, Jeon JH, Kang SS, Chung DK, Yun CH, Han SH. IgE in the absence of allergen induces the expression of monocyte chemoattractant protein-1 in the rat basophilic cell-line RBL-2H3. Mol Immunol 2014; 62:114-21. [DOI: 10.1016/j.molimm.2014.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/28/2014] [Accepted: 06/08/2014] [Indexed: 11/27/2022]
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Jin J, Liu X, Sun Y. The prevalence of increased serum IgE and Aspergillus sensitization in patients with COPD and their association with symptoms and lung function. Respir Res 2014; 15:130. [PMID: 25359094 PMCID: PMC4216660 DOI: 10.1186/s12931-014-0130-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/14/2014] [Indexed: 01/12/2023] Open
Abstract
Background Allergy and Aspergillus hypersensitivity (AH) were shown to be associated with severe symptoms or worse lung function in COPD patients. The prevalence of elevated total IgE (T-IgE) and its association with clinical symptoms and lung function in COPD have not been studied. The prevalence of AH and its correlation with clinical characteristics in a COPD cohort of larger sample size is also lacking. Methods 273 patients with COPD were evaluated by respiratory symptoms, blood test, chest HRCT, lung function, serum detection of T-IgE and Aspergillus specific IgE. Patients with T-IgE ≥ 1000 KU/L were further investigated for allergic bronchopulmonary aspergillosis (ABPA). Results The prevalence of elevated T-IgE and AH in patients with COPD was 47.3% and 15.0%, respectively. Eight patients (2.9%) met the diagnostic criteria for ABPA. Compared with the normal T-IgE group, patients with elevated T-IgE had a longer history of dyspnea (p < 0.01), an earlier onset of dyspnea after chronic cough/expectoration (p < 0.01), and were more likely to wheeze (p < 0.01). They also showed worse lung functions and more severe GOLD staging (p < 0.01). Analysis of the clinical data in male patients with smoking as the risk factor showed the same results. To evaluate the clinical characteristics of COPD with AH, patients with elevated T-IgE were further divided into subgroups with and without AH. When compared with the normal T-IgE group, both the two subgroups showed longer history of dyspnea (p < 0.01), an earlier onset of dyspnea (p < 0.01) and a worse status of lung function (p < 0.05). Correlation analysis demonstrated that T-IgE was correlated positively with the time length of dyspnea (r = 0.401, p < 0.001), and the ratio of duration of dyspnea to that of chronic cough/expectoration (r = 0.59, p < 0.001), but negatively with FEV1/FVC% (r = −0.194, p = 0.001), and FEV1%predicted (r = −0.219, p < 0.001). Conclusions There was a high prevalence of elevated serum T-IgE and AH in patients with COPD. Serum T-IgE level was correlated with symptoms such as dyspnea and impairment of lung function. Allergens other than Aspergillus may have similar effects on disease expression or progression of COPD.
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Affiliation(s)
| | | | - Yongchang Sun
- Department of Respiratory Medicine, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
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Mauri P, Riccio AM, Rossi R, Di Silvestre D, Benazzi L, De Ferrari L, Dal Negro RW, Holgate ST, Canonica GW. Proteomics of bronchial biopsies: galectin-3 as a predictive biomarker of airway remodelling modulation in omalizumab-treated severe asthma patients. Immunol Lett 2014; 162:2-10. [PMID: 25194755 DOI: 10.1016/j.imlet.2014.08.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 08/13/2014] [Indexed: 12/22/2022]
Abstract
Asthma is a chronic inflammatory disease. Reticular basement membrane (RBM) thickening is considered feature of airway remodelling (AR) particularly in severe asthma (SA). Omalizumab, mAb to IgE is effective in SA and can modulate AR. Herein we describe protein profiles of bronchial biopsies to detect biomarkers of anti-IgE effects on AR and to explain potential mechanisms/pathways. We defined the bronchial biopsy protein profiles, before and after treatment. Unsupervised clustering of baseline proteomes resulted in very good agreement with the morphometric analysis of AR. Protein profiles of omalizumab responders (ORs) were significantly different from those of non-omalizumab responders (NORs). The major differences between ORs and NORs lied to smooth muscle and extra cellular matrix proteins. Notably, an IgE-binding protein (galectin-3) was reliable, stable and predictive biomarker of AR modulation. Omalizumab down-regulated bronchial smooth muscle proteins in SA. These findings suggest that omalizumab may exert disease-modifying effects on remodelling components.
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Affiliation(s)
- Pierluigi Mauri
- Institute for Biomedical Technologies (ITB-CNR), Milan, Italy
| | - Anna Maria Riccio
- Allergy and Respiratory Diseases Unit, Dpt. of Internal Medicine, University of Genoa, IRCCS-IST AOU San Martino, Genoa, Italy
| | - Rossana Rossi
- Institute for Biomedical Technologies (ITB-CNR), Milan, Italy
| | | | - Louise Benazzi
- Institute for Biomedical Technologies (ITB-CNR), Milan, Italy
| | - Laura De Ferrari
- Allergy and Respiratory Diseases Unit, Dpt. of Internal Medicine, University of Genoa, IRCCS-IST AOU San Martino, Genoa, Italy
| | | | - Stephen T Holgate
- Inflammation, Infection and Immunity Division, Sir Henry Wellcome Laboratories, Mail Point 810, Level F, South Block, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Giorgio Walter Canonica
- Allergy and Respiratory Diseases Unit, Dpt. of Internal Medicine, University of Genoa, IRCCS-IST AOU San Martino, Genoa, Italy.
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Caminati M, Senna G, Chieco Bianchi F, Marchi MR, Vianello A, Micheletto C, Pomari C, Tognella S, Savoia F, Mirisola V, Rossi A. Omalizumab management beyond clinical trials: the added value of a network model. Pulm Pharmacol Ther 2014; 29:74-9. [PMID: 24508951 DOI: 10.1016/j.pupt.2014.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/24/2014] [Accepted: 01/25/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Omalizumab is effective and safe in severe allergic asthma. Few data are available about its impact on lung function and on asthma comorbidities, long-term follow-up of treated patients, adherence, non-responders profile, and optimal treatment duration. OBJECTIVE We aimed at evaluating omalizumab-related clinical outcomes and unmet needs in a real-life setting. METHODS We created a collaborative network (NEONet - North East Omalizumab Network) involving 9 Allergy and Respiratory referral centres for severe asthma placed in the North-East of Italy. Patients' data were entered into a common study database shared by all the participating physicians. A preliminary retrospective analysis was performed. RESULTS Patients come from a common well-defined geographical and environmental district providing a homogeneous population sample. A moderate but statistically significant improvement of the FEV1, and an increasing proportion of exacerbations-free patients were observed since the treatment start. These findings were independent of the baseline severity of bronchial obstruction. A positive impact of omalizumab on rhinitis in patients with both asthma and rhinitis was detected. Moreover the efficacy of omalizumab on asthma seemed not to be affected by the baseline severity of rhinitis. CONCLUSION Our retrospective analysis represents a preliminary report from the NEONet activity. It confirmed omalizumab efficacy and provided some new insights about its impact on lung function and on comorbid rhinitis. The network approach, under a prospective view, allows creating a large uniform database, by means of a standardized shared tool for data collecting, and joining a multidisciplinary expertise.
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Affiliation(s)
- Marco Caminati
- Allergy Unit, Verona University and General Hospital, Verona, Italy.
| | - Gianenrico Senna
- Allergy Unit, Verona University and General Hospital, Verona, Italy.
| | - Fulvia Chieco Bianchi
- Respiratory Pathophysiology Division, University-City Hospital of Padua, Padua, Italy.
| | - Maria Rita Marchi
- Respiratory Pathophysiology Division, University-City Hospital of Padua, Padua, Italy.
| | - Andrea Vianello
- Respiratory Pathophysiology Division, University-City Hospital of Padua, Padua, Italy.
| | | | - Carlo Pomari
- Respiratory Unit, Sacro Cuore Don Calabria General Hospital, Negrar, Verona, Italy.
| | - Silvia Tognella
- Respiratory Unit, Orlandi General Hospital, Bussolengo, Verona, Italy.
| | - Francesca Savoia
- Respiratory Pathophysiology Division, University-City Hospital of Padua, Padua, Italy.
| | | | - Andrea Rossi
- Pulmonary Unit, Verona University and General Hospital, Verona, Italy.
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Redhu NS, Shan L, Al-Subait D, Ashdown HL, Movassagh H, Lamkhioued B, Gounni AS. IgE induces proliferation in human airway smooth muscle cells: role of MAPK and STAT3 pathways. Allergy Asthma Clin Immunol 2013; 9:41. [PMID: 24499258 PMCID: PMC3842672 DOI: 10.1186/1710-1492-9-41] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 10/01/2013] [Indexed: 12/27/2022] Open
Abstract
Airway remodeling is not specifically targeted by current asthma medications, partly owing to the lack of understanding of remodeling mechanisms, altogether posing great challenges in asthma treatment. Increased airway smooth muscle (ASM) mass due to hyperplasia/hypertrophy contributes significantly to overall airway remodeling and correlates with decline in lung function. Recent evidence suggests that IgE sensitization can enhance the survival and mediator release in inflammatory cells. Human ASM (HASM) cells express both low affinity (FcεRII/CD23) and high affinity IgE Fc receptors (FcεRI), and IgE can modulate the contractile and synthetic function of HASM cells. IgE was recently shown to induce HASM cell proliferation but the detailed mechanisms remain unknown. We report here that IgE sensitization induces HASM cell proliferation, as measured by 3H-thymidine, EdU incorporation, and manual cell counting. As an upstream signature component of FcεRI signaling, inhibition of spleen tyrosine kinase (Syk) abrogated the IgE-induced HASM proliferation. Further analysis of IgE-induced signaling depicted an IgE-mediated activation of Erk 1/2, p38, JNK MAPK, and Akt kinases. Lastly, lentiviral-shRNA-mediated STAT3 silencing completely abolished the IgE-mediated HASM cell proliferation. Collectively, our data provide mechanisms of a novel function of IgE which may contribute, at least in part, to airway remodeling observed in allergic asthma by directly inducing HASM cell proliferation.
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Affiliation(s)
| | | | | | | | | | | | - Abdelilah S Gounni
- Department of Immunology, Faculty of Medicine, University of Manitoba, 419 Apotex Centre- 750 McDermot Ave, Winnipeg, MB R3E 0T5, Canada.
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A simple dot-blot-Sirius red-based assay for collagen quantification. Anal Bioanal Chem 2013; 405:6863-71. [PMID: 23780225 DOI: 10.1007/s00216-013-7101-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/24/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
The assessment of collagen content in tissues is important in biomedical research, since this protein is altered in numerous diseases. Hydroxyproline and Sirius red based assays are the most common methods for collagen quantification. However, these procedures have some pitfalls, such as the requirement of oxygen-free medium or expensive equipment and large sample size or being unsuitable for hydrolyzed collagen, respectively. Our objective was to develop a specific, versatile, and user-friendly quantitative method applicable to small tissue samples and extracts obtained from elastin purification, therefore, suitable for simultaneous quantification of elastin. This method is based on the binding of Sirius red to collagen present in a sample immobilized on a PVDF membrane, as in the dot-blot technique, and quantified by a scanner and image analysis software. Sample loading, Sirius red concentration, temperature and incubation time, type of standard substance, albumin interference, and quantification time are optimized. The method enabled the quantification of (1) intact collagen in several rat tissue homogenates, including small resistance-sized arteries, (2) partially hydrolyzed collagen obtained from NaOH extracts, compatible with elastin purification, and (3) for the detection of differences in collagen content between hypertensive and normotensive rats. We conclude that the developed technique can be widely used since it is versatile (quantifies intact and hydrolyzed collagen), requires small sample volumes, is user-friendly (low-cost, easy to use, minimum toxic materials, and reduced time of test), and is specific (minimal interference with serum albumin).
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