Purpose of review In this review, we describe the ‘state-of-the- art’ in our knowledge of asthma and what gaps exists, which can be exploited in the future for effective translation of our knowledge from the bench or population studies to diagnosis and therapy. Recent findings The advent of microbiome research has expounded the potential role of microbes in asthma. There has been significant increase in our understanding the pathologic, genetic, cellular and molecular mechanisms of asthma. Nonetheless, the contribution of microbes to the genesis, exacerbation and treatment of asthma are poorly understood. Summary Asthma is a complex chronic disease of the lung whose incidence is growing at all ages despite the progress that has been made in the areas of diagnosis and treatment of asthma. The complexity is partly due to the environmental insults such allergens and microbial infections that play differential roles in the pathogenesis of childhood vis-à-vis elderly asthma. Microbes may play important roles in the exacerbation of asthma and hence in the co-morbidities due to asthma, and also in the causation of asthma.

BackgroundAsthma is a complex disorder of the immune system caused by a combination of genetic predisposition with environmental exposures. The environmental factors play a predominant role in the etiology of asthma. It is hypothesized that epigenetic changes in miRNAs play a critical role in pathogenesis of asthma as an interface between genetic makeup and environmental exposures. (Wang, Jia-wang; Li, Kunyu; Hellermann, Gary; Lockey, Richard F.; Mohapatra, Subhra; and Mohapatra, Shyam. Regulating the Regulators: microRNA and Asthma. World Allergy Organization Journal. June 2011, Volume 4, Issue 6).MethodsIn the present study, we used miRNA array profiling in a mouse model of ovalbumin-induced asthma to identify differentially regulated miRNAs and characterized miR-150 in terms of cellular and humoral involvement and analysis of lung inflammation markers.ResultsWe found that miR-150 was downregulated in CD4 T lymphocytes during asthmatic inflammation and Th1 and Th2 induction. Over-expression of miR-150 delivered by chitosan nanoparticles inhibited lung inflammation and decreased Th1 and Th2 cytokine levels. miR-150 suppressed Akt3, Cbl1 and Elk1 oncogenes, which are involved in inflammation and cytokine production. Transgenic mice overexpressing miR-150 are resistant to asthma induction, demonstrated by reduced AHR and cytokine inflammation production.ConclusionsThese results suggest that deregulation of miRNAs may be involved in the pathogenesis of asthma and miR-150 may suppress inflammation in asthma by inhibiting cytokine production by downregulating critical genes such as Akt, Elk1 and Cbl1. miR-150 may be an attractive candidate for asthma gene therapy.

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BackgroundmiRNAs can be used as robust biomarkers for diagnosis, staging, prognosis and the response to therapy in various diseases. Although a wide spectrum of miRNA detection techniques have been developed, none can accurately and sensitively perform genome-wide high-throughput miRNA profiling (Chen C, Ridzon DA, Broomer AJ, Zhou Z, Lee DH, Nguyen JT, Barbisin M, Xu NL, et al 2005. Real-time quantification of microRNAs by stem-loop RT-PCR. Nucleic Acids Res. 33:e179). This problem stems from that miRNAs are only ∼22 bases, and multiple species of nucleic acids that contain the mature miRNA sequences are present in the total RNA samples that are usually used for miRNA detection.MethodsA novel RT-qPCR miRNA assay (UQmiR, universally quantitating miRNA) was developed to overcome the difficulty. This assay requires only one RT reaction and one universal set of multiple hydrolysis probes to detect all miRNAs, using one universal RT primer, a common reverse primer, and individual miRNA-specific forward primers. A computer program (MSPPD, miRNA-specific primer and probe designer) was developed for the assay.ResultsThe UQmiR has the advantages, but not the disadvantages, of the 2 mostly used miRNA assays. It has the specificity of hydrolysis probe assay and the universal detection of SYBR Green assay. This assay is more sensitive and specific than the commercially available hydrolysis probe assay and SYBR Green assay. Using this method, we have successfully detected 91 out of 96 miRNAs in 0.8 mL of plasma for each miRNA.ConclusionsThis approach affords a highly specific, sensitive, economical and convenient system to profile the expression of all known miRNAs.