Genomics, proteomics and metabolomics
Modern techniques including genomics (transcriptomics), proteomics and metabolomics provide comprehensive and un-biased approaches to study biological systems, identify previously un-recognized mechanistic pathways in health and disease, and establish endotypes within a disease81-83. Systems biology has provided a more holistic understanding of diseases and endotypes 81-83. Proteomic analysis of nasal mucus and mucosa in CRS suggested a trend of increased presence of immunological, metabolic, tissue remodeling and apoptotic pathways in CRS 84,85. Metabolomics analysis of low molecular weight compounds (up to 1,500 Da) has been performed in CRS 83. Fazlollahi et al. found that fatty acids (palmitic, oleic, stearic, and lauric) were highly elevated in CRSwNP compared to CRSsNP and control tissues 86. Miyata found impaired synthesis of cyclooxygenase- and lipoxygenase-derived mediators (including prostaglandin D2[PGD2], PGE2, thromboxane B2, 15-hydroxyeicosatetraenoic acid and lipoxin A4) and selective upregulation of leukotriene D4 in nasal polyp-derived eosinophils compared to healthy peripheral blood eosinophils 87. Future proteome and metabolome studies will require larger sample size and higher reproducibility to identify endotypes. In contrast, transcriptome analysis by microarray and RNA-Sequencing has been successfully used to characterize not only phenotype-specific (e.g. CRSsNP and CRSwNP) but also endotype-specific (e.g. eosinophilic and non-eosinophilic) gene expression profiles in CRS.