Connor et al. show that transcriptomic profiling of DCs exposed to two different Th2 stimuli in vivo reveals large numbers of differentially expressed genes but few similarities between conditions.

SignificanceT helper 2 (Th2) cells are defined by their ability to produce the hallmark cytokine IL-4. However, to mediate allergic inflammation in tissues, Th2 cells must secrete additional cytokines including IL-13 and IL-5. We used IL-4 and IL-13 dual-reporter mice to show that naive CD4+ T cells cultured in the presence of IL-4 and thymic stromal lymphopoietin (TSLP) generate a population of IL-4negIL-13pos Th2 cells that develop from IL-4neg precursors and express the Th2 effector cytokines IL-5 and IL-9. In vivo, high TSLP levels promote the development of a similar population of IL-4negIL-13pos T cells that also express Gata3, Il5, and Il3 transcripts. Thus, TSLP drives the early differentiation of a distinct population of effector Th2 cells with pro-inflammatory properties.

Following a nanopore sequencing run of PCR products of three amplicons less than 1kb, an abundance of reads failed quality control due to template/complement mismatch. A BLAST search demonstrated that some of the failed reads mapped to two different genes -- an unexpected observation, given that PCR was carried out separately for each amplicon. A further investigation was carried out specifically to search for chimeric reads, using separate barcodes for each amplicon and trying two different ligation methods prior to sample loading. Despite the separation of ligation products, chimeric reads formed from different amplicons were still observed in the base-called sequence. The long-read nature of nanopore sequencing presents an effective tool for the discovery and filtering of chimeric reads. We have found that at least 1.7% of reads prepared using the Nanopore LSK002 2D Ligation Kit include post-amplification chimeric elements. This finding has potential implications for other amplicon sequencing technologies, as the process is unlikely to be specific to the sample preparation used for nanopore sequencing.

Following a nanopore sequencing run of PCR products of three amplicons less than 1kb, an abundance of reads failed quality control due to template/complement mismatch. A BLAST search demonstrated that some of the failed reads mapped to two different genes -- an unexpected observation, given that PCR was carried out separately for each amplicon. A further investigation was carried out specifically to search for chimeric reads, using separate barcodes for each amplicon and trying two different ligation methods prior to sample loading. Despite the separation of ligation products, chimeric reads formed from different amplicons were still observed in the base-called sequence.The long-read nature of nanopore sequencing presents an effective tool for the discovery and filtering of chimeric reads. We have found that at least 1.7% of reads prepared using the Nanopore LSK002 2D Ligation Kit include post-amplification chimeric elements. This finding has potential implications for other amplicon sequencing technologies, as the process is unlikely to be specific to the sample preparation used for nanopore sequencing.

The induction of Th2 responses is thought to be multifactorial, and emerge from specific pathways distinct from those associated with antagonistic antibacterial or antiviral Th1 responses. Here, we show that the recognition of non-viable Nippostrongylus brasiliensis (Nb) in the skin induces a strong recruitment of monocytes and neutrophils and the release of neutrophil extracellular traps (NETs). Nb also activates toll-like receptor 4 (TLR4) signaling with expression of Ifnb transcripts in the skin and the development of an IFN type I signature on helminth antigen-bearing dendritic cells in draining lymph nodes. Co-injection of Nb together with about 10,000 Gram-negative bacteria amplified this TLR4-dependent but NET-independent IFN type I response and enhanced the development of Th2 responses. Thus, a limited activation of antibacterial signaling pathways is able to boost antihelminthic responses, suggesting a role for bacterial sensing in the optimal induction of Th2 immunity.

Graphical abstract

Graphical abstract

Background MicroRNAs (miRNAs) are cell-specific small non-coding RNAs that can regulate gene expression and have been implicated in Inflammatory Bowel Disease (IBD) pathogenesis. In our study, we define the cell-specific miRNA profiles and investigate its biomarker potential in IBD. Methods In a 2-stage prospective multi-centre case control study, Next Generation sequencing was performed on a discovery cohort of immunomagnetically separated leucocytes from 32 patients (9 CD, 14 UC, 8 healthy controls) and differentially expressed signals were validated in whole blood in 294 patients (97 UC, 98 CD, 98 non-IBD) using quantitative PCR. Correlations were analysed with phenotype, including need for early treatment escalation as a marker of progressive disease using Cox proportional hazards. Results In stage 1, each leucocyte subset (CD4+ and CD8+ T-cells and CD14+ monocytes) was analysed in IBD and controls. Three specific miRNAs differentiated IBD from controls in CD4+ T-cells, including miR-1307-3p (p=0.01), miR-3615 (p=0.02) and miR-4792 (p=0.01). In the extension cohort, in stage 2, miR-1307-3p was able to predict disease progression in IBD (HR 1.98, IQR:1.20-3.27;logrank p=1.80×10-3), in particular CD (HR 2.81; IQR: 1.11-3.53, p=6.50×10-4). Using blood-based multimarker miRNA models, the estimated chance of escalation in CD was 83% if 2 or more criteria were met and 90% for UC if 3 or more criteria are met. Interpretation We have identified and validated unique CD4+ T-cell miRNAs that are differentially regulated in IBD. These miRNAs may be able to predict treatment escalation and have the potential for clinical translation; further prospective evaluation is now indicated.