Project description:Chitin is the second most abundant polysaccharide in nature and a biomolecule intimately linked to fungal infection and allergic asthma, conditions that affect millions of patients worldwide. Chitin is known to stimulate multiple mammalian immune cells, but the precise molecular sensing mechanism has not been elucidated, hampering strategies to specifically target chitin-mediated pathologies. The study associated with this microarray dataset uses defined chitin oligomers to identify six chitin subunits as the smallest immunologically active chitin motif and the innate immune receptor TLR2 as the molecular chitin sensor on human and murine immune cells, in vitro and in vivo. The goal of this microarray dataset was to elucidate transcriptional differences of human whole blood cells when responding to chitin, to other TLR2 ligands (Pam2, Pam3), and furthermore to the TLR4 ligand LPS. All four stimulants are compared to each other and to the unstimulated whole blood samples as a reference. We conclude that chitin oligomers elicitd overlapping yet distinct signaling outcomes compared to canonical TLR2 ligands.
Project description:Use of human whole blood for transcriptomic analysis has potential advantages over the use of isolated immune cells for studying the transcriptional response to pathogens and their products. Whole blood stimulation can be carried out in a laboratory without the expertise or equipment to isolate immune cells from blood, with the added advantage of being able to undertake experiments using very small volumes of blood. Toll like receptors (TLRs) are a family of pattern recognition receptors which recognise highly conserved microbial products. Using the TLR2 ligand (Pam3CSK4) and the TLR4 ligand (LPS) human whole blood was stimulated for 0, 1, 3, 6, 12 or 24 hours at which times mRNA was isolated and a comparative microarray was undertaken. A common NFκB transcriptional programme was identified following both TLR2 and TLR4 ligation which peaked at between 3 to 6 hours including upregulation of many of the NFκB family members. In contrast an interferon transcriptional response was observed following TLR4 but not TLR2 ligation as early as 1 hour post stimulation and peaking at 6 hours. These results recapitulate the findings observed in previously published studies using isolated murine and human myeloid cells indicating that in vitro stimulated human whole blood can be used to interrogate the transcriptional kinetics response of innate cells to TLR ligands. Our study demonstrates that with a systems biology approach analysis of mRNA isolated from human whole blood can delineate both the temporal response and the key transcriptional differences following TLR2 and TLR4 ligation. 6 healthy human volunteers. 1ml whole blood stimulated in vitro with either LPS (1ng/ml), Pam3CSK4 (200ng/ml) or media for 0, 1, 3, 6 12 or 24 hours.
Project description:Use of human whole blood for transcriptomic analysis has potential advantages over the use of isolated immune cells for studying the transcriptional response to pathogens and their products. Whole blood stimulation can be carried out in a laboratory without the expertise or equipment to isolate immune cells from blood, with the added advantage of being able to undertake experiments using very small volumes of blood. Toll like receptors (TLRs) are a family of pattern recognition receptors which recognise highly conserved microbial products. Using the TLR2 ligand (Pam3CSK4) and the TLR4 ligand (LPS) human whole blood was stimulated for 0, 1, 3, 6, 12 or 24 hours at which times mRNA was isolated and a comparative microarray was undertaken. A common NFκB transcriptional programme was identified following both TLR2 and TLR4 ligation which peaked at between 3 to 6 hours including upregulation of many of the NFκB family members. In contrast an interferon transcriptional response was observed following TLR4 but not TLR2 ligation as early as 1 hour post stimulation and peaking at 6 hours. These results recapitulate the findings observed in previously published studies using isolated murine and human myeloid cells indicating that in vitro stimulated human whole blood can be used to interrogate the transcriptional kinetics response of innate cells to TLR ligands. Our study demonstrates that with a systems biology approach analysis of mRNA isolated from human whole blood can delineate both the temporal response and the key transcriptional differences following TLR2 and TLR4 ligation.
Project description:Chitin is the second most abundant polysaccharide in nature and a biomolecule intimately linked to fungal infection and allergic asthma, conditions that affect millions of patients worldwide. Chitin is known to stimulate multiple mammalian immune cells, but the precise molecular sensing mechanism has not been elucidated, hampering strategies to specifically target chitin-mediated pathologies. Using defined chitin oligomers we here identify six chitin subunits as the smallest immunologically active chitin motif and the innate immune receptor TLR2 as the molecular chitin sensor on human and murine immune cells, in vitro and in vivo. Chitin oligomers directly bound TLR2 with nanomolar affinity and elicited overlapping yet distinct signaling outcomes compared to canonical TLR2 ligands. Conversely, chitin oligomers composed of five chitin subunits acted as antagonists of chitin-TLR2 immune activation, hinting to an anti-inflammatory loop already known from plants, to also operate in humans. Of note, small chitin oligomers and biological-based blocking of the TLR2-chitin interaction effectively prevented chitin-mediated inflammation not only in vitro but also in vivo. Collectively, our study elucidates the molecular basis of how chitin is sensed by mammalian immune cells, which has broad impact for chitin-associated inflammatory pathologies. From a translational perspective, our findings further suggests that differently sized chitin oligomers could be developed into novel vaccine adjuvants or immuno-modulatory antagonists for the prevention or treatment of chitin-driven diseases in humans.
Project description:We performed a systematic analysis of the coding and non-coding transcriptomes of human macrophages after stimulation with ligands to TLR2/6 (FSL), TLR 1/2 (Pam3CSK4), and TLR4 (LPS)
Project description:Exposure of human monocytes to lipopolysaccharide (LPS) or other pathogen-associated molecular pattern (PAMPs) induces a temporary insensitivity to subsequent LPS challenges, a cellular state called endotoxin tolerance (ET). The tolerant state of monocytes is accompanied by cell surface and other glycoprotein expression changes induced by the activation of Toll-like receptors (TLRs). In this study, we aimed to characterize the cellular state of human monocytes stimulated with Gram-positive Staphylococcus aureus and TLR2 ligands. We analyzed gene expression changes induced by S. aureus after 2 and 24 hours by amplicon sequencing (RNA-AmpliSeq) and compared the pro-inflammatory response after 2 hours of stimulation to the to the response in re-stimulation experiments after the first stimulus. In parallel, glycoprotein expression changes in human monocytes after 24 hours of S. aureus stimulation were analyzed by proteomics and compared to stimulation experiments with TLR2 ligands Malp-2 and Pam3Cys and TLR4 ligand LPS. The results demonstrate that monocytes stimulated with S. aureus and TLR ligands entered the tolerant cell state after activation. Compared to TLR agonist mediated activation and tolerization of monocytes, glycoprotein expression changes induced by S. aureus stimulation revealed significant differences in receptor expression profiles. We report a glycoprotein expression profile characteristic for PAMP and S. aureus tolerized human monocytes. Finally, we analyzed peripheral blood monocytes of patients with S. aureus bloodstream infection for inflammatory responses in vitro and for their glycoprotein expression profiles. RNA-AmpliSeq data from patient-derived monocytes demonstrated that the cells were pro-inflammatory responsive to S. aureus stimulation and expressed higher level of CD44 mRNA, while other markers of the tolerant cell state were not detected.
Project description:In this study, we report that the TLR4 ligand, LPS, and TLR3 ligand polyinosinic:polycytidylic acid failed to activate IRF3 or STAT1 in bone marrow–derived macrophages (BMMs) isolated from two independently generated lines of Rosa26-integrated Cas9-expressing C57BL/6J (B6) mice. RNA-sequencing analysis reveals that hundreds to thousands of genes including IFN-stimulated genes were differentially expressed in BMMs from these Cas9 strains compared with B6 upon LPS stimulation. Furthermore, the NF-kB signaling axis and TRIF-mediated necroptosis were also strongly reduced in response to LPS and polyinosinic:polycytidylic acid. In contrast, there were no defects in the responses of BMMs to ligands of the RIG-I, STING, TLR2, TLR9, and IFN receptors. Defects in TLR3 and TLR4 signaling were observed in mice with the B6 but not 129 background, and when Cas9 was integrated at the Rosa26 but not H11 locus. However, integration at the Rosa26 site, CAG promoter–driven Cas9 or eGFP were not individually sufficient to cause the defect. Taken together, the results of this study suggest a putative TRIF-mediated defect in TLR-3/4 signaling in BMMs from commercially available and widely used B6–Cas9–expressing mice. ImmunoHorizons, 2021, 5: 818–829.
Project description:A cyanobacterial LPS antagonist prevents endotoxin shock and blocks sustained TLR4 stimulation required for cytokine expression. We report the identification and biologic characterization of an LPS-like molecule extracted from the cyanobacterium Oscillatoria Planktothrix FP1 (CyP). Keywords: different ligands
Project description:Here we implemented a simple dendritic cell (DC)-mediated immunization approach to study the effects of commonly used adjuvants, Toll like receptor (TLR) ligands, on effector CD8 T cell differentiation and memory T cell development. To our surprise, we found that the TLR4 ligand LPS was far more superior to other TLR ligands in generating memory CD8 T cells upon immunization. LPS boosted clonal expansion similar to the other adjuvants, but fewer of the activated CD8 T cells died during contraction, generating a larger pool of memory cells. Intriguingly, monophosphoryl lipid A (MPLA), another TLR4 ligand, enhanced clonal expansion of effector CD8 T cells, but also promoted their terminal differentiation and contraction; thus, fewer memory CD8 T cells formed and MPLA-primed animals were less protected against secondary infection compared to those primed with LPS. Furthermore, gene expression profiling revealed that LPS-primed effector cells displayed a stronger pro-memory gene expression signature, whereas the gene expression profile of MPLA-primed effector cells had aligned closer with terminal effector CD8 T cells. Mice that contain small number of P14 CD8 T cells were immunized with DC-33 either alone or in combination with LPS or MPLA. KLRG1loIL-7Rhi MPECs were purified by FACS sort, and mRNA isolated from MPECs was subjected to whole-genome expression profiling using Illumina MouseWG-6 v2.0 Expression BeadChip.
Project description:human blood monocytes were isolated, activated and harvested at several timepoints In this study, we identified genes that were differentially expressed in human monocytes activated with eiter NOD2L and/or TLR2/1L. human blood monocytes were purified from healthy donors by Ficoll, Percoll and adherence. Monocytes were activated using NOD2L (MDP) and the TLR2/1L (19kD, triacylated peptide). Cells were harvested before activation (0h) and 6h and 24h after stimulation with ligands.