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Osteopontin is increased in the bronchoalveolar lavage fluid and bronchial tissue of smoking asthmatics
Cytokine 61 (2013) 713–715
Contents lists available at SciVerse ScienceDirect
Cytokine journal homepage: www.journals.elsevier.com/cytokine
Letter Osteopontin is increased in the bronchoalveolar lavage fluid and bronchial tissue of smoking asthmatics
To the Editor, Osteopontin (OPN), originally characterized as a TH1 cytokine [1], has recently been associated with allergic inflammation [2]. Our group has extensively studied OPN’s role in the context of allergy and asthma [3–7]. Thus, we read with great interest the article by Hillas et al. in the latest issue of your journal [8]. The authors evaluated OPN levels in sputum supernatants and found them significantly increased in smoking asthmatics. Moreover, OPN levels were associated with sputum neutrophilia, IL-8 and TGF-b1 levels. Bronchoalveolar lavage fluid (BALF) and especially bronchial biopsies remain the gold standard for examining bronchial inflammation in inflammatory obstructive respiratory diseases. We have substantial preliminary data on smoking and OPN expression in the serum, BALF and bronchial tissue of asthmatics that we feel could significantly add to the aforementioned article by Hillas et al. [8]. Our ongoing study compares non-smoking healthy controls (n = 8), smoking but otherwise healthy controls (n = 8), non-smoking (n = 9) and smoking moderate-to-severe asthmatics (n = 9). All patients were receiving therapy depending on their asthma severity. Subjects underwent flexible bronchoscopy and OPN was quantified in the serum and BALF by means of ELISA and in bronchial tissue by means of immunohistochemistry, as previously described [4,5]. Group comparisons were performed by non-parametric one-way ANOVA followed by Bonferoni post hoc analysis, and correlation coefficients by Spearman’s rank method. Data are presented as mean ± SEM. One-way ANOVA revealed significant differences between groups regarding BALF and serum OPN levels (p = 0.0098 and p = 0.0027, respectively), with smoking controls exhibiting similar levels to non-smoking asthmatics, while asthmatic smokers exhibited the highest levels. Post-hoc analysis showed a significant difference only between asthmatic smokers and control non-smokers regarding both BALF and serum (p < 0.01) (Fig. 1A and 1B). OPN expression in bronchial tissue was increased in all groups compared to non-smoking controls (Fig. 1C), with differences between groups being statistically significant in both the epithelium (p = 0.0017) and subepithelium (p = 0.0014) (Fig. 1D and 1E). Moreover, smoking controls had increased epithelial and subepithelial OPN expression to levels similar to those of asthmatics. Interestingly, the effect of smoking on OPN expression was more prominent in the epithelium, as control smokers had significantly higher epithelial OPN expression compared to non-smokers (p < 0.5). Finally, a statistically significant correlation was found between OPN levels and neutrophils in BALF (r = 0.35, p < 0.05) (Fig. 1F). Recent in vitro and in vivo studies have indicated that OPN is potentially involved in the pathogenesis of smoking-related obstructive and interstitial lung disease [9,10]. Our findings of increased expression of OPN in the serum, BALF and bronchial tissue 1043-4666/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.cyto.2012.12.028
of healthy smokers and smoking asthmatics are in par with these previous reports of smoke-induced upregulation of OPN expression, as well as the findings by Hillas and colleagues in sputum supernatant of smoking asthmatics. Although our data are preliminary and underpowered, we did find a significant upregulation of OPN in the epithelial bronchial lining of healthy and asthmatic smokers, where smoke exposure is the highest. The correlation of OPN expression to BALF neutrophilia suggests a very plausible role for OPN as a chemotactic agent for neutrophils. OPN has previously been associated with eosinophilic-driven allergic inflammation [11]. However, OPN is characterized by heavy post-translational modifications resulting in distinct isoforms with diverse functionalities [12,13]. It is thus not unlikely that it acts differently in smoking as compared to non-smoking asthmatics. OPN’s exact role in smoking-aggravated airway inflammation is yet to be explored. References [1] Jansson M, Panoutsakopoulou V, Baker J, Klein L, Cantor H. Cutting edge: attenuated experimental autoimmune encephalomyelitis in eta-1/ osteopontin-deficient mice. J Immunol 2002;168:2096–9. [2] Konno S, Kurokawa M, Uede T, Nishimura M, Huang SK. Role of osteopontin, a multifunctional protein, in allergy and asthma. Clin Exp Allergy 2011;41:1360–6. [3] O’Neil SE, Malmhall C, Samitas K, Pullerits T, Bossios A, Lotvall J. Quantitative expression of osteopontin in nasal mucosa of patients with allergic rhinitis: effects of pollen exposure and nasal glucocorticoid treatment. Allergy Asthma Clin Immunol 2010;6:28. [4] Samitas K, Zervas E, Vittorakis S, Semitekolou M, Alissafi T, Bossios A, et al. Osteopontin expression and relation to disease severity in human asthma. Eur Respir J 2011;37:331–41. [5] Xanthou G, Alissafi T, Semitekolou M, Simoes DC, Economidou E, Gaga M, et al. Osteopontin has a crucial role in allergic airway disease through regulation of dendritic cell subsets. Nat Med 2007;13:570–8. [6] Samitas K, Zervas E, Panoutsakopoulou V, Gaga M. Letter to the editor– osteopontin levels in human asthma. J Int Med Res 2011;39:2441–2. [7] Simoes DC, Xanthou G, Petrochilou K, Panoutsakopoulou V, Roussos C, Gratziou C. Osteopontin deficiency protects against airway remodeling and hyperresponsiveness in chronic asthma. Am J Respir Crit Care Med 2009;179:894–902. [8] Hillas G, Loukides S, Kostikas K, Simoes D, Petta V, Konstantellou E, et al. Increased levels of osteopontin in sputum supernatant of smoking asthmatics. Cytokine 2013 Jan;61(1):251–5. [9] Prasse A, Stahl M, Schulz G, Kayser G, Wang L, Ask K, et al. Essential role of osteopontin in smoking-related interstitial lung diseases. Am J Pathol 2009;174:1683–91. [10] Bishop E, Theophilus EH, Fearon IM. In vitro and clinical studies examining the expression of osteopontin in cigarette smoke-exposed endothelial cells and cigarette smokers. BMC Cardiovasc Disord 2012;12:75. [11] Takahashi A, Kurokawa M, Konno S, Ito K, Kon S, Ashino S, et al. Osteopontin is involved in migration of eosinophils in asthma. Clin Exp Allergy 2009;39(8):1152–9. [12] Butler WT. Structural and functional domains of osteopontin. Ann NY Acad Sci 1995;760:6–11. [13] Shinohara ML, Kim HJ, Kim JH, Garcia VA, Cantor H. Alternative translation of osteopontin generates intracellular and secreted isoforms that mediate distinct biological activities in dendritic cells. Proc Natl Acad Sci USA 2008;105:7235–9.
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Letter / Cytokine 61 (2013) 713–715
Fig. 1. Osteopontin concentration in the (A) serum and (B) bronchoalveolar lavage fluid (BALF) of healthy non-smokers, healthy smokers, non-smoking asthmatics and smoking asthmatics. OPN is increased in all groups compared to healthy non-smokers. Smoking controls exhibit similar levels to non-smoking asthmatics, while asthmatic smokers show the highest levels and differ significantly from non-smoking controls. (C) Expression of OPN in the bronchial tissue of all groups using immunohistochemistry. Specific staining for OPN is brown, whereas nuclei are stained blue. Representative microphotographs are presented from a [1] healthy control non-smoker, [3] a nonsmoking asthmatic and [2] its corresponding isotype control, [4] a control smoker and [5] a smoking asthmatic. The region selected in [5] is presented in higher magnification in [6]. OPN tissue expression is shown in (D) the bronchial epithelium and (E) subepithelium, in all groups. Expression of OPN was higher in all groups compared to nonsmoker controls. Healthy smokers had significant higher OPN levels than healthy non-smokers only in the epithelium (D). Moreover, BALF OPN levels correlated significantly with neutrophils (F). : p < 0.05; : p < 0.01.
Letter / Cytokine 61 (2013) 713–715
Konstantinos Samitas a,b Eleftherios Zervas a Georgina Xanthou b Vily Panoutsakopoulou b ⇑ Mina Gaga a, a Seventh Respiratory Dept. and Asthma Centre, Athens Chest Hospital, Athens, Greece b Cellular Immunology Laboratory, Division of Cell Biology, Center for Basic Research, Foundation for Biomedical Research of the Academy of Athens, Greece
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⇑ Corresponding author. Address: Seventh Respiratory Dept. and Asthma Centre, Athens Chest Hospital, 152 Mesogion Ave., Athens 11527, Greece. Tel.: +30 210 7781720; fax: +30 210 7781911. E-mail address: [email protected] (M. Gaga)
Contents lists available at SciVerse ScienceDirect
Cytokine journal homepage: www.journals.elsevier.com/cytokine
Letter Osteopontin is increased in the bronchoalveolar lavage fluid and bronchial tissue of smoking asthmatics
To the Editor, Osteopontin (OPN), originally characterized as a TH1 cytokine [1], has recently been associated with allergic inflammation [2]. Our group has extensively studied OPN’s role in the context of allergy and asthma [3–7]. Thus, we read with great interest the article by Hillas et al. in the latest issue of your journal [8]. The authors evaluated OPN levels in sputum supernatants and found them significantly increased in smoking asthmatics. Moreover, OPN levels were associated with sputum neutrophilia, IL-8 and TGF-b1 levels. Bronchoalveolar lavage fluid (BALF) and especially bronchial biopsies remain the gold standard for examining bronchial inflammation in inflammatory obstructive respiratory diseases. We have substantial preliminary data on smoking and OPN expression in the serum, BALF and bronchial tissue of asthmatics that we feel could significantly add to the aforementioned article by Hillas et al. [8]. Our ongoing study compares non-smoking healthy controls (n = 8), smoking but otherwise healthy controls (n = 8), non-smoking (n = 9) and smoking moderate-to-severe asthmatics (n = 9). All patients were receiving therapy depending on their asthma severity. Subjects underwent flexible bronchoscopy and OPN was quantified in the serum and BALF by means of ELISA and in bronchial tissue by means of immunohistochemistry, as previously described [4,5]. Group comparisons were performed by non-parametric one-way ANOVA followed by Bonferoni post hoc analysis, and correlation coefficients by Spearman’s rank method. Data are presented as mean ± SEM. One-way ANOVA revealed significant differences between groups regarding BALF and serum OPN levels (p = 0.0098 and p = 0.0027, respectively), with smoking controls exhibiting similar levels to non-smoking asthmatics, while asthmatic smokers exhibited the highest levels. Post-hoc analysis showed a significant difference only between asthmatic smokers and control non-smokers regarding both BALF and serum (p < 0.01) (Fig. 1A and 1B). OPN expression in bronchial tissue was increased in all groups compared to non-smoking controls (Fig. 1C), with differences between groups being statistically significant in both the epithelium (p = 0.0017) and subepithelium (p = 0.0014) (Fig. 1D and 1E). Moreover, smoking controls had increased epithelial and subepithelial OPN expression to levels similar to those of asthmatics. Interestingly, the effect of smoking on OPN expression was more prominent in the epithelium, as control smokers had significantly higher epithelial OPN expression compared to non-smokers (p < 0.5). Finally, a statistically significant correlation was found between OPN levels and neutrophils in BALF (r = 0.35, p < 0.05) (Fig. 1F). Recent in vitro and in vivo studies have indicated that OPN is potentially involved in the pathogenesis of smoking-related obstructive and interstitial lung disease [9,10]. Our findings of increased expression of OPN in the serum, BALF and bronchial tissue 1043-4666/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.cyto.2012.12.028
of healthy smokers and smoking asthmatics are in par with these previous reports of smoke-induced upregulation of OPN expression, as well as the findings by Hillas and colleagues in sputum supernatant of smoking asthmatics. Although our data are preliminary and underpowered, we did find a significant upregulation of OPN in the epithelial bronchial lining of healthy and asthmatic smokers, where smoke exposure is the highest. The correlation of OPN expression to BALF neutrophilia suggests a very plausible role for OPN as a chemotactic agent for neutrophils. OPN has previously been associated with eosinophilic-driven allergic inflammation [11]. However, OPN is characterized by heavy post-translational modifications resulting in distinct isoforms with diverse functionalities [12,13]. It is thus not unlikely that it acts differently in smoking as compared to non-smoking asthmatics. OPN’s exact role in smoking-aggravated airway inflammation is yet to be explored. References [1] Jansson M, Panoutsakopoulou V, Baker J, Klein L, Cantor H. Cutting edge: attenuated experimental autoimmune encephalomyelitis in eta-1/ osteopontin-deficient mice. J Immunol 2002;168:2096–9. [2] Konno S, Kurokawa M, Uede T, Nishimura M, Huang SK. Role of osteopontin, a multifunctional protein, in allergy and asthma. Clin Exp Allergy 2011;41:1360–6. [3] O’Neil SE, Malmhall C, Samitas K, Pullerits T, Bossios A, Lotvall J. Quantitative expression of osteopontin in nasal mucosa of patients with allergic rhinitis: effects of pollen exposure and nasal glucocorticoid treatment. Allergy Asthma Clin Immunol 2010;6:28. [4] Samitas K, Zervas E, Vittorakis S, Semitekolou M, Alissafi T, Bossios A, et al. Osteopontin expression and relation to disease severity in human asthma. Eur Respir J 2011;37:331–41. [5] Xanthou G, Alissafi T, Semitekolou M, Simoes DC, Economidou E, Gaga M, et al. Osteopontin has a crucial role in allergic airway disease through regulation of dendritic cell subsets. Nat Med 2007;13:570–8. [6] Samitas K, Zervas E, Panoutsakopoulou V, Gaga M. Letter to the editor– osteopontin levels in human asthma. J Int Med Res 2011;39:2441–2. [7] Simoes DC, Xanthou G, Petrochilou K, Panoutsakopoulou V, Roussos C, Gratziou C. Osteopontin deficiency protects against airway remodeling and hyperresponsiveness in chronic asthma. Am J Respir Crit Care Med 2009;179:894–902. [8] Hillas G, Loukides S, Kostikas K, Simoes D, Petta V, Konstantellou E, et al. Increased levels of osteopontin in sputum supernatant of smoking asthmatics. Cytokine 2013 Jan;61(1):251–5. [9] Prasse A, Stahl M, Schulz G, Kayser G, Wang L, Ask K, et al. Essential role of osteopontin in smoking-related interstitial lung diseases. Am J Pathol 2009;174:1683–91. [10] Bishop E, Theophilus EH, Fearon IM. In vitro and clinical studies examining the expression of osteopontin in cigarette smoke-exposed endothelial cells and cigarette smokers. BMC Cardiovasc Disord 2012;12:75. [11] Takahashi A, Kurokawa M, Konno S, Ito K, Kon S, Ashino S, et al. Osteopontin is involved in migration of eosinophils in asthma. Clin Exp Allergy 2009;39(8):1152–9. [12] Butler WT. Structural and functional domains of osteopontin. Ann NY Acad Sci 1995;760:6–11. [13] Shinohara ML, Kim HJ, Kim JH, Garcia VA, Cantor H. Alternative translation of osteopontin generates intracellular and secreted isoforms that mediate distinct biological activities in dendritic cells. Proc Natl Acad Sci USA 2008;105:7235–9.
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Letter / Cytokine 61 (2013) 713–715
Fig. 1. Osteopontin concentration in the (A) serum and (B) bronchoalveolar lavage fluid (BALF) of healthy non-smokers, healthy smokers, non-smoking asthmatics and smoking asthmatics. OPN is increased in all groups compared to healthy non-smokers. Smoking controls exhibit similar levels to non-smoking asthmatics, while asthmatic smokers show the highest levels and differ significantly from non-smoking controls. (C) Expression of OPN in the bronchial tissue of all groups using immunohistochemistry. Specific staining for OPN is brown, whereas nuclei are stained blue. Representative microphotographs are presented from a [1] healthy control non-smoker, [3] a nonsmoking asthmatic and [2] its corresponding isotype control, [4] a control smoker and [5] a smoking asthmatic. The region selected in [5] is presented in higher magnification in [6]. OPN tissue expression is shown in (D) the bronchial epithelium and (E) subepithelium, in all groups. Expression of OPN was higher in all groups compared to nonsmoker controls. Healthy smokers had significant higher OPN levels than healthy non-smokers only in the epithelium (D). Moreover, BALF OPN levels correlated significantly with neutrophils (F). : p < 0.05; : p < 0.01.
Letter / Cytokine 61 (2013) 713–715
Konstantinos Samitas a,b Eleftherios Zervas a Georgina Xanthou b Vily Panoutsakopoulou b ⇑ Mina Gaga a, a Seventh Respiratory Dept. and Asthma Centre, Athens Chest Hospital, Athens, Greece b Cellular Immunology Laboratory, Division of Cell Biology, Center for Basic Research, Foundation for Biomedical Research of the Academy of Athens, Greece
715
⇑ Corresponding author. Address: Seventh Respiratory Dept. and Asthma Centre, Athens Chest Hospital, 152 Mesogion Ave., Athens 11527, Greece. Tel.: +30 210 7781720; fax: +30 210 7781911. E-mail address: [email protected] (M. Gaga)