Biology subjects

Yager, N.

Publications and source records attributed to Yager, N..

3 recordsLinked to original sources

bioRxiv2021

Ex vivo mass cytometry analysis reveals a profound myeloid proinflammatory signature in psoriatic arthritis synovial fluid

ObjectivesA number of immune populations have been implicated in psoriatic arthritis (PsA) pathogenesis. This study used mass cytometry (CyTOF) combined with transcriptomic analysis to generate a high-dimensional dataset of matched PsA synovial fluid (SF) and blood leucocytes, with the aim of identifying cytokine production ex vivo in unstimulated lymphoid and myeloid cells. MethodsFresh SF and paired blood were either fixed or incubated with protein transport inhibitors for 6 h. Samples were stained with two CyTOF panels: a phenotyping panel and an intracellular panel, including antibodies to both T cell and myeloid cell secreted proteins. Transcriptomic analysis by gene array of key expanded cell populations and single-cell RNA-seq, and ELISA and LEGENDplex analysis of PsA SF were also performed. ResultsWe observed marked changes in the myeloid compartment of PsA SF relative to blood, with expansion of intermediate monocytes, macrophages and dendritic cell populations. Classical monocytes, intermediate monocytes and macrophages spontaneously produced significant levels of the proinflammatory mediators osteopontin and CCL2 in the absence of any in vitro stimulation. By contrast minimal spontaneous cytokine production by T cells was detected. Gene expression analysis showed the genes for osteopontin and CCL2 to be amongst those most highly upregulated by PsA monocytes/macrophages; and both proteins were elevated in PsA SF. ConclusionsUsing multiomic analyses we have generated a comprehensive cellular map of PsA SF and blood to reveal key expanded myeloid proinflammatory modules in PsA of potential pathogenic and therapeutic importance.

immunology↗

bioRxiv2019

Single-cell sequencing reveals a clonal expansion of pro-inflammatory synovial CD8 T cells expressing tissue homing receptors in psoriatic arthritis

Psoriatic arthritis (PsA) is a debilitating immune-mediated inflammatory arthritis of unknown pathogenesis commonly affecting patients with skin psoriasis. We used three complementary single cell approaches to study leukocytes from PsA joints. Mass cytometry (CyTOF) demonstrated marked (>3 fold) expansion of memory CD8 T cells in the joints compared to matched blood. Further exploration of the memory CD8 compartment using both droplet and plate based single cell RNA sequencing of paired alpha and beta chain T cell receptor sequences identified pronounced CD8 T cell clonal expansions within the joints, strongly suggesting antigen driven expansion. These clonotypes exhibited distinct gene expression profiles including cycling, activation, tissue homing and tissue residency markers. Pseudotime analysis of these clonal CD8 populations identified trajectories in which tissue residency can represent an intermediate developmental state giving rise to activated, cycling and exhausted CD8 populations. Comparing T-cell clonality across patients further revealed specificity convergence of clones against a putative common antigen. We identify chemokine receptor CXCR3 as upregulated in expanded synovial clones, and elevation of two CXCR3 ligands, CXCL9 and CXCL10, in PsA synovial fluid.

immunology↗

bioRxiv2018

The Autoimmune Disease Risk Allele rs6897932 Modulates Monocyte IL7R Surface and Soluble Receptor Levels in a Context-Specific Manner

IL-7 is a key factor in T-cell immunity and IL7R polymorphisms are implicated in autoimmune pathogenesis. IL7R mRNA is induced in stimulated monocytes in a genetically determined manner, yet a role for IL7R in monocyte biology remains unexplored. Here we characterize genetic regulation of IL7R at the protein level across multiple cell subsets and conditions in healthy individuals. We find monocyte surface and soluble IL7R (sIL7R) protein are markedly expressed in response to lipopolysaccharide (LPS). We further demonstrate alleles of rs6897932, a non-synonymous IL7R polymorphism associated with susceptibility to Multiple Sclerosis, Ankylosing Spondylitis and Primary Biliary Cirrhosis, form the key determinant of both surface IL7R and sIL7R in the context of inflammation. No effect of this allele was observed in unstimulated monocytes or across lymphoid subsets. Production of sIL7R by monocytes greatly exceeded that of CD4+ T-cells, and was strongly associated with both rs6897932 genotype and expression of the splicing factor gene DDX39A. Stimulated monocytes were sensitive to exogenous IL-7, which elicits a defined transcriptional signature. Flow cytometry and single-cell sequencing of synovial fluid derived monocytes from patients with spondyloarthritis showed an enlarged subset of IL7R+ monocytes with a unique transcriptional profile that markedly overlaps that induced by IL-7 in-vitro and shows similarity to the previously described Mono4 subset. These data demonstrate disease-associated genetic variants at IL7R specifically impact monocyte surface IL7R and sIL7R following innate immune stimulation, suggesting a previously unappreciated key role for monocytes in IL-7 pathway biology and IL7R-associated diseases.

immunology↗