A number of autoimmunity-associated MHC class II proteins interact only weakly with the invariant chain-derived class II-associated invariant chain peptide (CLIP). CLIP dissociates rapidly from I-Ag7 even in the absence of DM, and this property is related to the type 1 diabetes-associated b57 polymorphism. We generated knock-in Non-obese Diabetic (NOD) mice with a single amino acid change in the CLIP segment of invariant chain in order to moderately slow CLIP dissociation from I-Ag7. These knock-in mice had a significantly reduced incidence of spontaneous type 1 diabetes and diminished islet infiltration by CD4 T cells, in particular T cells specific for fusion peptides generated by covalent linkage of proteolytic fragments within b cell secretory granules. Rapid CLIP dissociation enhanced presentation of such extracellular peptides, thus bypassing the conventional MHC class II antigen processing pathway. Autoimmunity-associated MHC class II polymorphisms therefore not only modify binding of self-peptides, but also alter the biochemistry of peptide acquisition. Overall design: Mouse pancreatic tissue was digested by collagenase, and islets were isolated and dissociated into single cells. Beta-cell-specific CD4 T cells were single-cell sorted by FACS based on tetramer labeling, and individual cells were profiled with a modified full length SMART-Seq2 protocol.
Rapid CLIP dissociation from MHC II promotes an unusual antigen presentation pathway in autoimmunity.
Specimen part, Subject
View SamplesUsing single-cell RNA-seq of intestinal epithelial cells we identify surprising expression of MHC class II, which participates in a novel interaction between gut-resident CD4+ T cells and epithelial stem cells, governing the balance between stem cell differentiation and renewal. Overall design: In the small intestine, a niche of accessory cell types supports the generation of mature epithelial cell types from intestinal stem cells (ISCs). It is unclear, however, if and how immune cells in the niche affect ISC fate or the balance between self-renewal and differentiation. Here, we use single-cell RNA sequencing (scRNA-seq) to identify MHC class II (MHCII) machinery enrichment in two subsets of Lgr5+ ISCs. We show that MHCII+ Lgr5+ ISCs are non-conventional antigen-presenting cells in co-cultures with CD4+ T helper (Th) cells. Stimulation of intestinal organoids with key Th cytokines affects Lgr5+ ISC renewal and differentiation in opposing ways: pro-inflammatory signals promote differentiation, while regulatory cells and cytokines reduce it. In vivo genetic perturbation of Th cells or MHCII expression on Lgr5+ ISCs impacts epithelial cell differentiation and IEC fate during infection. These interactions between Th cells and Lgr5+ ISCs, thus, orchestrate tissue-wide responses to external signals.
T Helper Cell Cytokines Modulate Intestinal Stem Cell Renewal and Differentiation.
Specimen part, Cell line, Treatment, Subject, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Competition between virus-derived and endogenous small RNAs regulates gene expression in Caenorhabditis elegans.
No sample metadata fields
View SamplesAnalysis of the transcriptional response to viral infection in C.elegans.
Competition between virus-derived and endogenous small RNAs regulates gene expression in Caenorhabditis elegans.
No sample metadata fields
View SamplesAttempt to identify small non-coding RNAs that change in levels as a result of viral infection of C.elegans Overall design: Small non-coding RNA (18-30nt) was extracted from animals either infected with Orsay virus or uninfected as indicated.
Competition between virus-derived and endogenous small RNAs regulates gene expression in Caenorhabditis elegans.
Cell line, Subject
View SamplesThe transition in developmental control from maternal to zygotic gene products marks a critical step in early embryogenesis. Here, we use GRO-seq analysis to map the genome-wide RNA polymerase distribution during the Drosophila maternal to zygotic transition. This analysis unambiguously identifies the zygotic transcriptome, and provides insight into its mechanisms of regulation. Overall design: Two replicates of GRO-seq at each time point.
Extensive polymerase pausing during Drosophila axis patterning enables high-level and pliable transcription.
Specimen part, Cell line, Subject, Time
View SamplesYeast cells were grown up in SD media containing all required amino acids. Each strain set was performed in triplicate. One set had no changes, the second set had 1mM methionine supplenting the media for the duration of growth and the third set was exposed to 0.5mM hydrogen peroxide for 15 minutes prior to harvesting
Gcn4 is required for the response to peroxide stress in the yeast Saccharomyces cerevisiae.
Compound
View SamplesGlobal restriction of protein synthesis is a hallmark of cellular stress. Using hydrogen peroxide, we monitor the transcript level and also the translation status for each RNA using cycloheximide to freeze elongating ribosomes. Polyribosome fractionation of cell extracts was used to separate highly translated and poorly translated mRNAs that were then separately analysed.
Global translational responses to oxidative stress impact upon multiple levels of protein synthesis.
Sex, Compound
View SamplesWnt signaling in early eye development, specifically the lens placode shows expression of 12 out of 19 Wnt ligands. We these Wnt activities were suppressed using conditional deletion of Wntless, dramatic phenotypic changes in morphogensis occurred.
Wnt ligands from the embryonic surface ectoderm regulate 'bimetallic strip' optic cup morphogenesis in mouse.
Specimen part
View SamplesThe coupling between cell-cycle exit and onset of differentiation is a common feature throughout the developing nervous system, but the mechanisms that link these processes are mostly unknown. Although the transcription factor Pax6 was implicated in both proliferation and differentiation of multiple regions within the CNS, its contribution to the transition between these successive states remains elusive. To gain insight into the role of Pax6 during the transition from proliferating progenitors to differentiating precursors, we investigated cell-cycle and transcriptomic changes occurring in Pax6- retinal progenitor cells (RPCs). Our analyses revealed a unique cell-cycle phenotype of the Pax6-deficient RPCs, which included a reduced number of cells in the S phase, an increased number of cells exiting the cell cycle, and delayed differentiation kinetics of Pax6- precursors. These alterations were accompanied by co-expression of factors that promote (Ccnd1, Ccnd2, Ccnd3) and inhibit (P27kip1 and P27kip2) the cell cycle. Further characterization of the changes in transcription profile of the Pax6-deficient RPCs revealed abrogated expression of multiple factors which are known to be involved in regulating proliferation of RPCs, including the transcription factors Vsx2, Nr2e1, Plagl1 and Hedgehog signaling. These findings provide novel insight into the molecular mechanism mediating the pleiotropic activity of Pax6 in RPCs. The results further suggest that rather than conveying a linear effect on RPCs, such as promoting their proliferation and inhibiting their differentiation, Pax6 regulates multiple transcriptional networks which function simultaneously, thereby conferring the capacity to proliferate, assume multiple cell fates and execute the differentiation program into retinal lineages.
Pax6 is required for normal cell-cycle exit and the differentiation kinetics of retinal progenitor cells.
Specimen part
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