Expression and functions of long noncoding RNAs during human T helper cell differentiation

To improve our understanding of lncRNA expression in T cells, we used whole genome sequencing (RNA-seq) to identify lncRNAs expressed in human T cells and those selectively expressed in T cells differentiated under TH1, TH2, or TH17 polarizing conditions. The majority of these lineage-specific lncRNAs are co-expressed with lineage-specific protein-coding genes. These lncRNAs are predominantly intragenic with co-expressed protein-coding genes and are transcribed in sense and antisense orientations with approximately equal frequencies. Further, genes encoding TH lineage specific mRNAs are not randomly distributed across the genome but are highly enriched in the genome in genomic regions also containing genes encoding TH lineage-specific lncRNAs. Our analyses also identify a cluster of antisense lncRNAs transcribed from the RAD50 locus that are selectively expressed under TH2 polarizing conditions and co-expressed with IL4, IL5 and IL13 genes. Depletion of these lncRNAs via selective siRNA treatment demonstrates the critical requirement of these lncRNAs for expression of the TH2 cytokines, IL-4, IL-5 and IL-13. Collectively, our analyses identify new lncRNAs expressed in a TH lineage specific manner and identify a critical role for a cluster of lncRNAs for expression of genes encoding TH2 cytokines. Human peripheral blood mononuclear cells (PBMC) were cultured under TH1, TH2, and TH17 polarizing conditions. TH1, TH2, and TH17 primary and effector cultures were isolated and poly(A)+ and total RNA sequencing performed.