Major Contribution of Myeloid Cells In TB specific Host Gene Signature: Revelations from Re-Analysis of Publicly Available Datasets

IntroductionInteraction of human host and its pathogen M.tuberculosis drives tuberculosis disease, resulting in dysregulation of host gene expression. We re-analyzed host gene expression datasets of TB to identify and validate a cellular circuit by interlinking the DEGs with their target miRNAs, GWAS hits associated with immunological phenotypes mapping to the DEGs and associated cellular subtypes through bioinformatic and experimental approaches. MethodologyDEGs were identified systematically through re-analysis of whole blood host transcriptomic datasets of treatment-naive TB patients, obtained from public repositories having at least 1.2 fold change of expression and FDR corrected p-value <0.05. Using well characterized M.tb antigens: Ag85 complex, LAM, CFP10 and ESAT6, we evaluated their effect on the expression of a subset of the top DEGs with at least two fold change of expression in a monocytic cell line THP1 with or without differentiation into a macrophage-like state with PMA and a T cell line Jurkat E6-1. ResultsWe discovered 305 DEGs (236 up and 69 down-regulated genes) out of which 23 (21 up and 2 down-regulated genes) were top DEGs. Overall, innate immune and myeloid cell associated pathways were enriched for up-regulated genes while T cell associated pathways were enriched for down-regulated genes. Among top DEGs, EPSTI1 was predominantly up-regulated in macrophages while SERPING1 was universally up-regulated in the monocyte model by all antigens. The down-regulation of gene expression was replicated by ESAT6 in T cell line by significantly down-regulating a top down-regulated gene LRRN3.