K. Ling

DNA Methylation Profiles of Airway Epithelial Cells and PBMCs from Healthy, Atopic and Asthmatic Children

Background Allergic inflammation is commonly observed in a number of conditions that are associated with atopy including asthma, eczema and rhinitis. However, the genetic, environmental or epigenetic factors involved in these conditions are likely to be different. Epigenetic modifications, such as DNA methylation, can be influenced by the environment and result in changes to gene expression. Objectives To characterize the DNA methylation pattern of airway epithelial cells (AECs) compared to peripheral blood mononuclear cells (PBMCs) and to discern differences in methylation within each cell type amongst healthy, atopic and asthmatic subjects. Methods PBMCs and AECs from bronchial brushings were obtained from children undergoing elective surgery for non-respiratory conditions. The children were categorized as atopic, atopic asthmatic, non-atopic asthmatic or healthy controls. Extracted DNA was bisulfite treated and 1505 CpG loci across 807 genes were analyzed using the Illumina GoldenGate Methylation Cancer Panel I. Gene expression for a subset of genes was performed using RT-PCR. Results We demonstrate a signature set of CpG sites that are differentially methylated in AECs as compared to PBMCs regardless of disease phenotype. Of these, 13 CpG sites were specific to healthy controls, 8 sites were only found in atopics, and 6 CpGs were unique to asthmatics. We found no differences in the methylation status of PBMCs between disease phenotypes. In AECs derived from asthmatics compared to atopics, 8 differentially methylated sites were identified including CpGs in STAT5A and CRIP1. We demonstrate STAT5A gene expression is decreased whereas CRIP1 gene expression is elevated in the AECs from asthmatic compared to both healthy and atopic subjects. Discussion We characterized a cell specific DNA methylation signature for AECs compared to PBMCs regardless of asthmatic or atopic status. Our data highlight the importance of understanding DNA methylation in the epithelium when studying the epithelial contribution to asthma.

The airway epithelium is a direct source of matrix degrading enzymes in bronchiolitis obliterans syndrome

BACKGROUND Long-term survival after lung transplantation is hindered by the development of bronchiolitis obliterans syndrome (BOS), and recent evidence suggests that dysregulated epithelial repair may underlie its development. Because matrix metalloproteinase (MMP) -2 and MMP-9 secretion is integral to repair, we hypothesized that airway epithelial cells from patients with BOS would over-express these matrix-degrading enzymes. METHODS Cells obtained from bronchial and bronchiolar brushings from patients with and without BOS (without acute rejection or infection) were analyzed via quantitative polymerase chain reaction and immunocytochemistry for MMP-2, and MMP-9 gene and protein expression. The expression of tissue inhibitor of metalloproteinase (TIMP)2 and TIMP1 was also assessed. MMP activity in bronchoalveolar lavage was determined via gelatin zymography. RESULTS MMP-2 and MMP-9 production was significantly higher in bronchoalveolar lavage (3.85- and 11.59-fold, p < 0.001) and airway epithelium (MMP-2 bronchial: 6.33-fold, bronchiolar: 3.57-fold, both p < 0.001; MMP-9 bronchial: 32.55-fold, p < 0.001; bronchiolar: 8.60-fold, p = 0.01) in patients with BOS, but expression in patients without BOS was not different from healthy controls. TIMP expression was similar in patients with and without BOS. Immunostaining confirmed that the airway epithelium was a direct source of MMP-2 and MMP-9 expression in patients with BOS. CONCLUSION In patients with BOS, the airway epithelium over-expresses MMPs, even in the absence of acute rejection or infection. Dysregulated epithelial repair may be a key feature of BOS.

Bronchial brushings for investigating airway inflammation and remodelling

Asthma is the commonest medical cause for hospital admission for children in Australia, affects more than 300 million people worldwide, and is incurable, severe in large number and refractory to treatment in many. However, there have been no new significant treatments despite intense research and billions of dollars. The advancement in our understanding in this disease has been limited due to its heterogeneity, genetic complexity and has severely been hampered particularly in children by the difficulty in obtaining relevant target organ tissue. This review attempts to provide an overview of the currently used and recently developed/adapted techniques used to obtain lung tissue with specific reference to the airway epithelium.

Suppression of adrenomedullin contributes to vascular leakage and altered epithelial repair during asthma

The anti‐inflammatory peptide, adrenomedullin (AM), and its cognate receptor are expressed in lung tissue, but its pathophysiological significance in airway inflammation is unknown.

DYSREGULATED REPAIR AND EPITHELIAL INJURY IN SMALL AND LARGE AIRWAYS OF LUNG TRANSPLANT PATIENTS IS AMELIORATED BY AZITHROMYCIN

ABRAMSON M, TO 077, TO 083, TP 073, TP 078, TP 081, TP 083 ACWORTH J, TP 058, TP 059 ADAMS L, TP 008, TP 221 ADAMS R, TO 108, TP 215 ADELSTEIN S, TP 111 AGAR M, TP 126, TP 127 AHERN J, TO 088 AIYAPPAN V, TP 209 ALAGAPPAN V, TP 176, TP 180 ALDRIDGE K, TO 047 ALEXANDER S, TO 103, TP 133, TP 172, TP 173 ALFONSO H, TO 013 ALI A, TO 106 ALISON J, TO 092 ALLEN K, TP 083 ALLEN L, TP 183 ALLEN P, TP 125 ALLISON B, TP 064 ALSUBAIEI M, TP 181 AMEER F, TO 074, TO 080 AMINAZAD A, TO 042, TP 130 ANDERSON G, TO 090, TO 095, TO 111, TP 016 ANDERSON J, TP 054 ANDERSON T, TO 052 ANDERSON-JAMES S, TP 058 ANDRÉ P, TO 014, TP 028 ANNAMALAY A, TP 207 ANTHONY D, TO 112 ANTIC N, TO 108, TP 215 ANTIC R, TP 129, TP 228 ANZUETO A, TP 169, TP 170 APPLETON S, TO 108, TP 215 AREST CF O, TO 058 ARETS H, AO 009 ARMOUR C, TO 036, TP 084, TP 149 ARMSTRONG D, TO 029, TP 057 ARTIGAS M, TO 065 ASHTON A, TP 077 ATTOKARAN A, TO 084 AU H, TO 107 AVRAAM J, AO 003 AZZOPARDI M, TP 124, TP 187