Biology subjects

Lord, G. M.

Publications and source records attributed to Lord, G. M..

3 recordsLinked to original sources

bioRxiv2021

The Th1 cell regulatory circuitry is largely conserved between human and mouse

Gene expression programmes controlled by lineage-determining transcription factors are often conserved between species. However, infectious diseases have exerted profound evolutionary pressure, and therefore the genes regulated by immune-specific transcription factors might be expected to exhibit greater divergence due to exposure to species-specific pathogens. T-bet (Tbx21) is the immune-specific lineage-defining transcription factor for T helper type I (Th1) immunity, which is fundamental for the immune response to intracellular pathogens but also underlies inflammatory diseases. We therefore compared T-bet genomic targets between mouse and human CD4+ T cells and correlated T-bet binding patterns with species-specific gene expression. Remarkably, we show that the vast majority of T-bet regulated genes are conserved between mouse and human, either via preservation of a binding site or via an alternative binding site associated with transposon-linked insertion. We also identified genes that are specifically targeted by T-bet in humans or mice and which exhibited species-specific expression. These results provide a genome-wide cross-species comparison of T-bet target gene regulation that will enable more accurate translation of genetic targets and therapeutics from pre-clinical models of inflammatory disease into human clinical trials.

immunology↗

bioRxiv2020

A population of CD4+ T cells with a naive phenotype stably polarized to the TH1 lineage

T-bet is the lineage-specifying transcription factor for CD4+ T helper type 1 (TH1) cells. T-bet has also been found in other CD4+ T cell subsets, including TH17 cells and TREG, where it modulates their functional characteristics. However, we lack information on when and where T-bet is expressed during T cell differentiation and how this impacts T cell function. To address this, we traced the ontogeny of T-bet-expressing cells using a fluorescent fate-mapping mouse line. We demonstrate that T-bet is expressed in a subset of CD4+ T cells with naive cell surface markers and that this novel cell population is phenotypically and functionally distinct from conventional naive CD4+ T cells. These cells are also distinct from previously described populations of memory phenotype and stem cell-like T cells. Naive-like T-bet-experienced cells are polarised to the TH1 lineage, predisposed to produce IFN{gamma} upon cell activation, and resist repolarisation to other lineages in vitro and in vivo. These results demonstrate that lineage-specifying factors can function to polarise T cells in the absence of canonical markers of T cell activation and that this has an impact on the subsequent T helper response.

immunology↗

bioRxiv2020

ILC1-derived TGFβ1 drives intestinal remodelling

Organoids can shed light on the dynamic interplay between complex tissues and rare cell types within a controlled microenvironment. Here, we developed gut organoid co-cultures with type-1 innate lymphoid cells (ILC1) to dissect the impact of their accumulation in inflamed intestines. We demonstrate for the first time that murine and human ILC1 secrete TGF{beta}1, driving expansion of CD44v6+ epithelial crypts. ILC1 additionally express MMP9 and drive gene signatures indicative of extracellular matrix remodelling. We therefore encapsulated human epithelial-mesenchymal intestinal organoids in MMP-sensitive, synthetic hydrogels designed to form efficient networks at low polymer concentrations. Harnessing this defined system, we demonstrate that ILC1 drive matrix softening and stiffening, which we suggest occurs through balanced matrix degradation and deposition. Our platform enabled us to elucidate previously undescribed interactions between ILC1 and their microenvironment, which suggest that they may exacerbate fibrosis and tumour growth when enriched in inflamed patient tissues.

immunology↗