Partner: Werner Müller |
Recent publications
1. | Kalliara E.♦, Kardynska M.♦, Bagnall J.♦, Spiller David G.♦, Müller W.♦, Ruckerl D.♦, Śmieja J.♦, Biswas Subhra K.♦, Paszek P., Post-transcriptional regulatory feedback encodes JAK-STAT signal memory of interferon stimulation, Frontiers in Immunology, ISSN: 1664-3224, DOI: 10.3389/fimmu.2022.947213, Vol.13, pp.947213-1-19, 2022 Abstract: Immune cells fine tune their responses to infection and inflammatory cues. Here, using live-cell confocal microscopy and mathematical modelling, we investigate interferon-induced JAK-STAT signalling in innate immune macrophages. We demonstrate that transient exposure to IFN-γ stimulation induces a long-term desensitisation of STAT1 signalling and gene expression responses, revealing a dose- and time-dependent regulatory feedback that controls JAK-STAT responses upon re-exposure to stimulus. We show that IFN-α/β1 elicit different level of desensitisation from IFN-γ, where cells refractory to IFN-α/β1 are sensitive to IFN-γ, but not vice versa. We experimentally demonstrate that the underlying feedback mechanism involves regulation of STAT1 phosphorylation but is independent of new mRNA synthesis and cognate receptor expression. A new feedback model of the protein tyrosine phosphatase activity recapitulates experimental data and demonstrates JAK-STAT network’s ability to decode relative changes of dose, timing, and type of temporal interferon stimulation. These findings reveal that STAT desensitisation renders cells with signalling memory of type I and II interferon stimulation, which in the future may improve administration of interferon therapy. Keywords:JAK-STAT network, STAT1 kinetics, interferons, pathway desensitisation, mathematical modelling, signal memory, live-cell microscopy Affiliations:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
2. | Papoutsopoulou S.♦, Burkitt Michael D.♦, Bergey F.♦, England H.♦, Hough R.♦, Schmidt L.♦, Spiller David G.♦, White Michael H. R.R.♦, Paszek P.♦, Jackson Dean A.♦, Martins Dos Santos Vitor A. P.♦, Sellge G.♦, Pritchard D. M.♦, Campbell Barry J.♦, Müller W.♦, Probert Chris S.♦, Macrophage-Specific NF-κB Activation Dynamics Can Segregate Inflammatory Bowel Disease Patients, Frontiers in Immunology, ISSN: 1664-3224, DOI: 10.3389/fimmu.2019.02168, Vol.10, pp.2168-1-11, 2019 Abstract: The heterogeneous nature of inflammatory bowel disease (IBD) presents challenges, particularly when choosing therapy. Activation of the NF-κB transcription factor is a highly regulated, dynamic event in IBD pathogenesis. Using a lentivirus approach, NF-κB-regulated luciferase was expressed in patient macrophages, isolated from frozen peripheral blood mononuclear cell samples. Following activation, samples could be segregated into three clusters based on the NF-κB-regulated luciferase response. The ulcerative colitis (UC) samples appeared only in the hypo-responsive Cluster 1, and in Cluster 2. Conversely, Crohn's disease (CD) patients appeared in all Clusters with their percentage being higher in the hyper-responsive Cluster 3. A positive correlation was seen between NF-κB-induced luciferase activity and the concentrations of cytokines released into medium from stimulated macrophages, but not with serum or biopsy cytokine levels. Confocal imaging of lentivirally-expressed p65 activation revealed that a higher proportion of macrophages from CD patients responded to endotoxin lipid A compared to controls. In contrast, cells from UC patients exhibited a shorter duration of NF-κB p65 subunit nuclear localization compared to healthy controls, and CD donors. Analysis of macrophage cytokine responses and patient metadata revealed a strong correlation between CD patients who smoked and hyper-activation of p65. These in vitro dynamic assays of NF-κB activation in blood-derived macrophages have the potential to segregate IBD patients into groups with different phenotypes and may therefore help determine response to therapy. Keywords:inflammatory bowel disease, NF-kB, macrophages, cytokines, Crohn’s disease, ulcerative colitis Affiliations:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3. | Bagnall J.♦, Boddington C.♦, England H.♦, Brignall R.♦, Downton P.♦, Alsoufi Z.♦, Boyd J.♦, Rowe W.♦, Bennett A.♦, Walker C.♦, Adamson A.♦, Patel Nisha M. X.♦, O’Cualain R.♦, Schmidt L.♦, Spiller David G.♦, Jackson Dean A.♦, Müller W.♦, Muldoon M.♦, White Michael R. H.R.♦, Paszek P.♦, Quantitative analysis of competitive cytokine signaling predicts tissue thresholds for the propagation of macrophage activation, Science Signaling, ISSN: 1945-0877, DOI: 10.1126/scisignal.aaf3998, Vol.11, No.540, pp.1-15, 2018 Abstract: Toll-like receptor (TLR) signaling regulates macrophage activation and effector cytokine propagation in the constrained environment of a tissue. In macrophage populations, TLR4 stimulates the dose-dependent transcription of nuclear factor κB (NF-κB) target genes. However, using single-RNA counting, we found that individual cells exhibited a wide range (three orders of magnitude) of expression of the gene encoding the proinflammatory cytokine tumor necrosis factor–α (TNF-α). The TLR4-induced TNFA transcriptional response correlated with the extent of NF-κB signaling in the cells and their size. We compared the rates of TNF-α production and uptake in macrophages and mouse embryonic fibroblasts and generated a mathematical model to explore the heterogeneity in the response of macrophages to TLR4 stimulation and the propagation of the TNF-α signal in the tissue. The model predicts that the local propagation of the TLR4-dependent TNF-α response and cellular NF-κB signaling are limited to small distances of a few cell diameters between neighboring tissue-resident macrophages. In our predictive model, TNF-α propagation was constrained by competitive uptake of TNF-α from the environment, rather than by heterogeneous production of the cytokine. We propose that the highly constrained architecture of tissues enables effective localized propagation of inflammatory cues while avoiding out-of-context responses at longer distances. Affiliations:
|