Allergy, Asthma and Immunology

September 5, 2013

The dopamine D1 receptor is expressed and facilitates relaxation in airway smooth muscle

Research

Kentaro Mizuta, Yi Zhang, Dingbang Xu, Fumiko Mizuta, Frank D¿Ovidio, Eiji Masaki andCharles W Emala

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Respiratory Research 2013, 14:89 doi:10.1186/1465-9921-14-89

Published: 2 September 2013

Abstract (provisional)

Background

Dopamine signaling is mediated by Gs protein-coupled "D1-like" receptors (D1 and D5) and Gi-coupled "D2-like" receptors (D2-4). In asthmatic patients, inhaled dopamine induces bronchodilation. Although the Gi-coupled dopamine D2 receptor is expressed and sensitizes adenylyl cyclase activity in airway smooth muscle (ASM) cells, the Gs-coupled dopamine D1-like receptor subtypes have never been identified on these cells. Activation of Gs-coupled receptors stimulates cyclic AMP (cAMP) production through the stimulation of adenylyl cyclase, which promotes ASM relaxation. We questioned whether the dopamine D1-like receptor is expressed on ASM, and modulates its function through Gs-coupling.

Methods

The mRNA and protein expression of dopamine D1-like receptor subtypes in both native human and guinea pig ASM tissue and cultured human ASM (HASM) cells was measured. To characterize the stimulation of cAMP through the dopamine D1 receptor, HASM cells were treated with dopamine or the dopamine D1-like receptor agonists (A68930 or SKF38393) before cAMP measurements. To evaluate whether the activation of dopamine D1 receptor induces ASM relaxation, guinea pig tracheal rings suspended under isometric tension in organ baths were treated with cumulatively increasing concentrations of dopamine or A68930, following an acetylcholine-induced contraction with or without the cAMP-dependent protein kinase (PKA) inhibitor Rp-cAMPS, the large-conductance calcium-activated potassium (BKCa) channel blocker iberiotoxin, or the exchange proteins directly activated by cAMP (Epac) antagonist NSC45576.

Results

Messenger RNA encoding the dopamine D1 and D5 receptors were detected in native human ASM tissue and cultured HASM cells. Immunoblots confirmed the protein expression of the dopamine D1 receptor in both native human and guinea pig ASM tissue and cultured HASM cells. The dopamine D1 receptor was also immunohistochemically localized to both human and guinea pig ASM. The dopamine D1-like receptor agonists stimulated cAMP production in HASM cells, which was reversed by the selective dopamine D1-like receptor antagonists SCH23390 or SCH39166. A68930 relaxed acetylcholine-contracted guinea pig tracheal rings, which was attenuated by Rp-cAMPS but not by iberiotoxin or NSC45576.

Conclusions

These results demonstrate that the dopamine D1 receptors are expressed on ASM and regulate smooth muscle force via cAMP activation of PKA, and offer a novel target for therapeutic relaxation of ASM.

The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.

Stan Szefler, MD talks with Michael Wechsler, MD about Dr. Wechsler's new JACI article "Bronchial thermoplasty: Long-term safety and effectiveness in patients with severe persistent asthma"

September 4, 2013

Significant, quantifiable differences exist between IgG subclass standards WHO67/97 and ERM-DA470k and can result in different interpretation of results

Clinical Biochemistry

Available online 25 July 2013

In Press, Corrected Proof — Note to users

^a Binding Site Group Limited, 8 Calthorpe Road, Birmingham B15 1QT, United Kingdom
^b Clinical Immunology & Allergy, GSTS Pathology, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom
^c Haifa and Western Galilee Laboratory, Clalit Health Services, 47 Hataasia St, Nesher 20300, PO Box 428, Haifa, Israel
^d Département de Biologie Clinique, Cliniques Universitaires Saint Luc, Avenue Hippocrate, 10, 1200 Brussels, Belgium

Open Access

Highlights

•: Samples from four testing sites were measured using commercial IgG subclass assays.
•: The assays are calibrated to two different reference materials.
•: Calibrations were similar for IgG1 and IgG2.
•: For IgG3 and IgG4, the calibrations were significantly different.
•: The two manufacturers' assays can give differing clinical classifications.

Abstract

Objectives

Accurate measurement of IgG subclass (IgGSc) levels are essential to aid in the diagnosis of disease states such as primary immunodeficiencies. However, there is no single standardisation of nephelometric and turbidimetric assays for these analytes and two reference materials have been utilised. We expand on previous reports and present data from a multi-site analysis that both identifies and quantitatively defines the differences in calibration resulting from the use of different reference materials.

Design and methods

IgGSc antibodies in the serum specimens and reference materials were measured according to the manufacturers' instructions using commercially available IgGSc assays or components.

Results

Data from four independent sites showed that in spite of the different commercial suppliers of IgGSc assays calibrating to different reference materials, ERM-DA470k and WHO67 /97, the resulting calibrations were comparable for IgG1 and IgG2. However, for IgG3 and IgG4 the calibrations were significantly different. The use of assay specific normal ranges should compensate for these calibration differences, however, the two manufacturers' assays can give differing clinical classifications. The agreement between the different manufacturers' IgGSc assays was between 85.1% and 95.8% for all IgGSc assays, the discordance of sample classification for IgG1 and IgG2 assays was approximately 12% and 15% respectively, whilst that for IgG3 and IgG4 was 4% and 13% respectively.

Conclusion

We discuss the similarities and differences between assays that utilise the different reference materials.

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Materials and methods

Measurement of assay performance and assay comparison

Table 1

Table 2

Quantitation of assay comparison

Effect of different calibrations on sample classification

Increased Numbers of NK Cells, NKT-Like Cells, and NK Inhibitory Receptors in Peripheral Blood of Patients with COPD

Clinical and Developmental Immunology
Volume 2013 (2013), Article ID 721782, 8 pages
http://dx.doi.org/10.1155/2013/721782

Clinical Study

Increased Numbers of NK Cells, NKT-Like Cells, and NK Inhibitory Receptors in Peripheral Blood of Patients with Chronic Obstructive Pulmonary Disease

Ying Tang,¹ Xiaodan Li,¹ Man Wang,¹ Qi Zou,¹ Shasha Zhao,¹ Bowen Sun,¹ Lijun Xu,¹ and Yanfang Jiang²

¹Department of Respiratory Medicine, The First Hospital, Jilin University, Changchun 130021, China
²Department of the Central Laboratory, The Second Part of the First Hospital, Jilin University, Changchun 130021, China

Received 11 January 2013; Revised 24 June 2013; Accepted 26 June 2013

Academic Editor: G. Opdenakker

Copyright © 2013 Ying Tang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

T cells and B cells participate in the pathogenesis of COPD. Currently, NK cells and NKT cells have gained increasing attention. In the present study, 19 COPD patients and 12 healthy nonsmokers (HNS) were recruited, and their pulmonary function was assessed. The frequencies of CD3⁺ T, CD4⁺ T, CD8⁺T, B, NK, and NKT-like cells were determined using flow cytometry. The frequencies of spontaneous and inducible IFN-γ⁺ or CD107a⁺ NK and NKT-like cells as well as activating or inhibitory receptors were also detected. The potential association of lymphocyte subsets with disease severity was further analyzed. Significantly decreased numbers of CD3⁺ and CD4⁺ T cells, and the CD4⁺/CD8⁺ ratio, but increased numbers of CD3⁻CD56⁺ NK and CD3⁺CD56⁺ NKT-like cells were observed in COPD patients compared to HNS. The frequencies of inducible IFN-γ-secreting NK and NKT-like cells were less in COPD patients. The frequencies of CD158a and CD158b on NK cells and CD158b on NKT-like cells were greater. The frequency of CD158b⁺ NK cells was negatively correlated with FEV₁% prediction and FEV₁/FVC. Our data indicate that COPD patients have immune dysfunction, and higher frequencies of inhibitory NK cells and NKT-like cells may participate in the pathogenesis of COPD.