Increased angiogenic factors in exhaled breath condensate of children with severe asthma - New markers of disease progression?

The role of human ribonuclease A family in health and diseases: A systematic review

The ribonuclease A (RNase A) family is one of the best-characterized vertebrate-specific proteins. In humans, eight catalytically active RNases (numbered 1–8) have been identified and have unique tissue distributions. Apart from the digestion of dietary RNA, a broad range of biological actions, including the regulation of intra- or extra-cellular RNA metabolism as well as antiviral, antibacterial, and antifungal activities, neurotoxicity, promotion of cell proliferation, anti-apoptosis, and immunomodulatory abilities, have been recently reported for the members of this family. Based on multiple biological roles, RNases are found to participate in the pathogenic processes of many diseases, such as infection, immune dysfunction, neurodegeneration, cancer, and cardiovascular disorders. This review summarizes the available data on the human RNase A family and illustrates the significant roles of the eight canonical RNases in health and disease, for stimulating further basic research and development of ideas on the potential solutions for disease diagnosis and treatment.

Exhaled breath condensates from healthy children induce cell death of in vitro cultured cells by activation of apoptosis

Introduction

Exhaled breath condensate (EBC) is a liquefied air, containing a mixture of non-volatile compounds, reflecting pathophysiological status of the bronchopulmonary system. Therefore, EBC analysis may be useful in diagnostics and monitoring of various respiratory diseases. In previous studies it was found that EBC from asthmatic children contained several regulators of angiogenesis. In vitro experiments with EBCs from children with asthma revealed their weak influence on proliferation of various cells. Surprisingly, EBCs from healthy children led to apoptosis of all tested cells.

Aim

To assess the expression of selected apoptosis-related proteins in human and murine cells exposed to EBC from healthy children.

Material and methods

EBCs from healthy children were added to cultures of murine endothelial cells (C166) or human lung fibroblasts (HLF) to induce their apoptosis. For proteome analysis the apoptosis pathway-specific protein microarrays were used.

Results

The homogenates from EBC-treated C166 cells contained low amounts of Hsp27, which correlated with their fast death. Contrary to C166, the lysates from EBC-treated fibroblasts displayed increased amounts of Hsp27, which correlated with delayed HLF response to the induction of apoptosis. Except for increased caspase-3 in EBC-treated HLF, none of the other apoptosis regulators revealed any significant changes in that analysis.

Conclusions

The screening of apoptosis pathways with microarray technology allowed identification of two molecules, Hsp27 and caspase-3, involved in cellular response to EBC. However, the factor responsible for induction of the cytotoxic effect of EBC from healthy children still remains unknown.

Influence of exhaled breath condensates from children with asthma on endothelial cells cultured in vitro. Do we really know everything about our breath condensate?

Introduction

Asthma-associated remodelling involves subepithelial fibrosis and increased vascularization of the bronchial wall. The latter may be associated with excessive production of several angiogenesis regulators which may be found in exhaled breath condensates (EBCs) collected from children with asthma.

Aim

To assess the influence of EBC samples of asthmatic children and healthy controls on in vitro cultures of normal human lung microvascular endothelial cells (HLMVEC) and murine endothelial cell line (C-166). Moreover, the proteomic profile of cytokines in EBC samples was analysed.

Material and methods

Breath condensates collected from children with mild asthma (n = 10) and from healthy controls (n = 10) were used for experiments. Colorimetric tetrazolium salt reduction assay was used to evaluate the effect of EBCs on HLMVEC and C-166 cell lines. Furthermore, influence of EBCs on C-166 cell line was assessed using Annexin V-binding assay. The cytokine screening of EBC samples was performed using a proteome microarray system.

Results

The EBCs from patients with asthma revealed a weak inhibitory influence on human and murine endothelial cells. Surprisingly, EBCs from healthy children led to cell death, mainly by the induction of apoptosis. There were no statistically significant differences in the cytokine profile between EBC samples from children with asthma and healthy controls.

Conclusions

Our preliminary report shows for the first time that the incubation of EBCs from healthy controls induced apoptosis in endothelial cells. The detailed mechanism responsible for this action remains unknown and requires further research.

Exhaled Breath Condensate in Childhood Asthma: A Review and Current Perspective

Exhaled breath condensate (EBC) was introduced more than two decades ago as a novel, non-invasive tool to assess airway inflammation. This review summarizes the latest literature on the various markers in EBC to predict asthma in children. Despite many recommendations and two comprehensive Task Force reports, there is still large heterogeneity in published data. The biggest issue remains a lack of standardization regarding EBC collection, preservation, processing, and analysis. As a result, published studies show mixed or conflicting results, questioning the reproducibility of findings. A joint, multicenter research study is urgently needed to address the necessary methodological standardization.

Unique mechanisms of connective tissue growth factor regulation in airway smooth muscle in asthma: Relationship with airway remodelling

Neovascularization, increased basal membrane thickness and increased airway smooth muscle (ASM) bulk are hallmarks of airway remodelling in asthma. In this study, we examined connective tissue growth factor (CTGF) dysregulation in human lung tissue and animal models of allergic airway disease. Immunohistochemistry revealed that ASM cells from patients with severe asthma (A) exhibited high expression of CTGF, compared to mild and non‐asthmatic (NA) tissues. This finding was replicated in a sheep model of allergic airways disease. In vitro, transforming growth factor (TGF)‐β increased CTGF expression both in NA‐ and A‐ASM cells but the expression was higher in A‐ASM at both the mRNA and protein level as assessed by PCR and Western blot. Transfection of CTGF promoter‐luciferase reporter constructs into NA‐ and A‐ASM cells indicated that no region of the CTGF promoter (−1500 to +200 bp) displayed enhanced activity in the presence of TGF‐β. However, in silico analysis of the CTGF promoter suggested that distant transcription factor binding sites may influence CTGF promoter activation by TGF‐β in ASM cells. The discord between promoter activity and mRNA expression was also explained, in part, by differential post‐transcriptional regulation in A‐ASM cells due to enhanced mRNA stability for CTGF. In patients, higher CTGF gene expression in bronchial biopsies was correlated with increased basement membrane thickness indicating that the enhanced CTGF expression in A‐ASM may contribute to airway remodelling in asthma.