Asthma Severity and Expression Of CLC3 On Human Peripheral Blood and Nasal Lavage Eosinophils

Abstract

RationaleWe have reported the role of CLC3 in TGF-β-induced migration and activation of eosinophils, and increased expression of CLC3b and CLC3e transcript variants on TGF-β and eotaxin-treated eosinophils. Severity of asthma and corticosteroid treatment may determine the CLC3 expression on eosinophils.MethodsEosinophils were isolated from human venous blood (>99%pure; >98%viable) with negative selection from healthy (n=10), mild-to-moderate (n=10) and moderate-to-severe (n=10) allergic asthmatics. Nasal washings were taken from respective groups. Q-PCR, Western blot, and fluorescence microscopy were used to obtain outcome measures.ResultsmRNA transcripts of CLC3 variants varied among groups based on the severity of asthma and corticosteroid treatment. Eosinophils from mild-to-moderate asthmatics had 5-6-fold increase in CLC3 mRNA transcripts compared to healthy volunteers. However, moderate-to-severe asthmatics on inhaled corticosteroid had 2-3-fold increase in CLC3 transcripts. The CLC3b and CLC3e transcripts were increased 5-7 and 6-8-fold in mild-to-moderate asthmatics, and in moderate-severe asthmatics increase by 4-5 and 3-4 fold, respectively. Protein expression of CLC3 also followed the same trend. Asthmatics nasal lavage contained multiple eosinophils expressing different levels of CLC3 with increased expression in mild-to-moderate than moderate-to-severe asthmatic and no inflammatory cells in healthy subjects.ConclusionsThe CLC3 expression on eosinophils correlates with asthma severity. Reduction in CLC3 expression may be an additional mechanism of corticosteroid effects in allergic airway inflammation. Differential CLC3 expression on nasal eosinophils could be a biomarker of asthma severity and treatment with corticosteroids. RationaleWe have reported the role of CLC3 in TGF-β-induced migration and activation of eosinophils, and increased expression of CLC3b and CLC3e transcript variants on TGF-β and eotaxin-treated eosinophils. Severity of asthma and corticosteroid treatment may determine the CLC3 expression on eosinophils. We have reported the role of CLC3 in TGF-β-induced migration and activation of eosinophils, and increased expression of CLC3b and CLC3e transcript variants on TGF-β and eotaxin-treated eosinophils. Severity of asthma and corticosteroid treatment may determine the CLC3 expression on eosinophils. MethodsEosinophils were isolated from human venous blood (>99%pure; >98%viable) with negative selection from healthy (n=10), mild-to-moderate (n=10) and moderate-to-severe (n=10) allergic asthmatics. Nasal washings were taken from respective groups. Q-PCR, Western blot, and fluorescence microscopy were used to obtain outcome measures. Eosinophils were isolated from human venous blood (>99%pure; >98%viable) with negative selection from healthy (n=10), mild-to-moderate (n=10) and moderate-to-severe (n=10) allergic asthmatics. Nasal washings were taken from respective groups. Q-PCR, Western blot, and fluorescence microscopy were used to obtain outcome measures. ResultsmRNA transcripts of CLC3 variants varied among groups based on the severity of asthma and corticosteroid treatment. Eosinophils from mild-to-moderate asthmatics had 5-6-fold increase in CLC3 mRNA transcripts compared to healthy volunteers. However, moderate-to-severe asthmatics on inhaled corticosteroid had 2-3-fold increase in CLC3 transcripts. The CLC3b and CLC3e transcripts were increased 5-7 and 6-8-fold in mild-to-moderate asthmatics, and in moderate-severe asthmatics increase by 4-5 and 3-4 fold, respectively. Protein expression of CLC3 also followed the same trend. Asthmatics nasal lavage contained multiple eosinophils expressing different levels of CLC3 with increased expression in mild-to-moderate than moderate-to-severe asthmatic and no inflammatory cells in healthy subjects. mRNA transcripts of CLC3 variants varied among groups based on the severity of asthma and corticosteroid treatment. Eosinophils from mild-to-moderate asthmatics had 5-6-fold increase in CLC3 mRNA transcripts compared to healthy volunteers. However, moderate-to-severe asthmatics on inhaled corticosteroid had 2-3-fold increase in CLC3 transcripts. The CLC3b and CLC3e transcripts were increased 5-7 and 6-8-fold in mild-to-moderate asthmatics, and in moderate-severe asthmatics increase by 4-5 and 3-4 fold, respectively. Protein expression of CLC3 also followed the same trend. Asthmatics nasal lavage contained multiple eosinophils expressing different levels of CLC3 with increased expression in mild-to-moderate than moderate-to-severe asthmatic and no inflammatory cells in healthy subjects. ConclusionsThe CLC3 expression on eosinophils correlates with asthma severity. Reduction in CLC3 expression may be an additional mechanism of corticosteroid effects in allergic airway inflammation. Differential CLC3 expression on nasal eosinophils could be a biomarker of asthma severity and treatment with corticosteroids. The CLC3 expression on eosinophils correlates with asthma severity. Reduction in CLC3 expression may be an additional mechanism of corticosteroid effects in allergic airway inflammation. Differential CLC3 expression on nasal eosinophils could be a biomarker of asthma severity and treatment with corticosteroids.