Biology subjects

Purnell, T.

Publications and source records attributed to Purnell, T..

5 recordsLinked to original sources

bioRxiv2024

DYRK1A kinase triplication is the major cause of Otitis Media in Down Syndrome

Down syndrome (DS), which arises from trisomy of the whole or part of chromosome 21 (Hsa21), is one of the most common genetic abnormalities in humans. DS manifests as a broad spectrum of phenotypic features, including hearing loss due to otitis media with effusion (OME), affecting around 50% of children with DS. We employed a panel of mouse models of DS comprising a nested series of duplications covering the regions of the mouse genome syntenic to Hsa21 in order to define the loci involved with OME in DS. We identified a major locus on mouse chromosome 16, containing only 12 genes, that causes OME. Within this region we demonstrate that normalizing the gene dosage of Dyrk1a restored the wild-type phenotype. Investigation of downstream pathways of DYRK1A uncovered a number of pathological mechanisms whereby DYRK1A triplication leads to middle ear inflammation and vascular leak. These include cross-talk of DYRK1A and TGF{beta} signaling and its impact on proinflammatory cytokines IL-6 and IL-17, as well as raised VEGF levels in the middle ear accompanied by increased Hif1a. We conclude that DYRK1A is a potential therapeutic target for OME in children with DS.

genetics↗

bioRxiv2024

Lung structural cell dynamics are altered by influenza virus infection experience leading to rapid immune protection following viral re-challenge

Lung structural cells, including epithelial cells and fibroblasts, form barriers against pathogens and trigger immune responses following infections such as influenza A virus. This response leads to the recruitment of innate and adaptive immune cells required for viral clearance. Some of these recruited cells remain within the lung following infection and contribute to enhanced viral control following subsequent infections. There is growing evidence that structural cells can also display long-term changes following infection or insults. Here we investigate long-term changes to mouse lung epithelial cells, fibroblasts, and endothelial cells following influenza virus infection and find that all three cell types maintain an imprint of the infection, particularly in genes associated with communication with T cells. Lung epithelial cells from IAV-infected mice display functional changes by more rapidly controlling influenza virus than cells from naive animals. This rapid anti-viral response and increased expression of molecules required to communicate with T cells demonstrates sustained and enhanced functions following infection. These data suggest lung structural cells could be effective targets for vaccines to boost durable protective immunity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/604410v5_ufig1.gif" ALT="Figure 1"> View larger version (55K): org.highwire.dtl.DTLVardef@2774e0org.highwire.dtl.DTLVardef@6a39e6org.highwire.dtl.DTLVardef@1ff5863org.highwire.dtl.DTLVardef@103df12_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LILung epithelial cells, fibroblasts, and blood endothelial cells maintain an inflammatory imprint of influenza A virus (IAV) infection for at least 40 days post-infection. C_LIO_LIIn vivo re-infection leads to a more spatially restricted anti-viral response compared to primary IAV-infected animals. C_LIO_LIT cells are not required for enhanced viral control early after re-infection in vivo C_LIO_LIEx vivo lung epithelial cells from IAV-infected mice more rapidly control IAV than cells from naive animals in the absence of immune cells. C_LI

immunology↗

bioRxiv2023

Lung influenza virus specific memory CD4 T cell location and optimal cytokine production are dependent on interactions with lung antigen-presenting cells

Influenza A virus (IAV) infection leads to the formation of mucosal memory CD4 T cells that can protect the host. An in-depth understanding of the signals that shape memory cell development is required for more effective vaccine design. We have examined the formation of memory CD4 T cells in the lung following IAV infection of mice, characterising changes to the lung landscape and immune cell composition. IAV-specific CD4 T cells were found throughout the lung at both primary and memory time points. These cells were found near lung airways and in close contact with a range of immune cells including macrophages, dendritic cells, and B cells. Interactions between lung IAV-specific CD4 T cells and MHCII+ cells during the primary immune response were important in shaping the subsequent memory pool. Treatment with an anti-MHCII blocking antibody increased the proportion of memory CD4 T cells found at lung airways but reduced interferon-g expression by IAV-specific immunodominant memory CD4 T cells. The immunodominant CD4 T cells expressed higher levels of PD1 than other IAV-specific CD4 T cells and PD1+ memory CD4 T cells were located further away from MHCII+ cells than their PD1-negative counterparts. This distinction in location was lost in mice treated with anti-MHCII antibody. These data suggest that sustained antigen presentation in the lung impacts on the formation of memory CD4 T cells by regulating their cytokine production and location.

immunology↗

bioRxiv2023

Triphasic production of IFNγ by innate and adaptive lymphocytes following influenza A virus infection

Interferon gamma (IFN{gamma}) is a potent antiviral cytokine that can be produced by many innate and adaptive immune cells during infection. Currently, our understanding of which cells produce IFN{gamma} and where they are located at different stages of an infection are limited. We have used reporter mice to investigate in vivo expression of IFN{gamma} in the lung and secondary lymphoid organs during and following influenza A virus (IAV) infection. We observed a triphasic production of IFN{gamma} expression. Unconventional T cells and innate lymphoid cells, particularly NK cells, were the dominant producers of early IFN{gamma}, while CD4 and CD8 T cells were the main producers by day 10 post-infection. Following viral clearance, some memory CD4 and CD8 T cells continued to produce IFN{gamma} in the lungs and draining lymph node. Interestingly, IFN{gamma} production by lymph node Natural Killer (NK), NKT and innate lymphoid 1 cells also continued to be above naive levels, suggesting memory-like phenotypes for these cells. Analysis of the localisation of IFN{gamma}+ memory CD4 and CD8 T cells demonstrated that cytokine+ T cells were located near airways and in the lung parenchyma. Following a second IAV challenge, lung IAV specific CD8 T cells rapidly increased their expression of IFN{gamma} while CD4 T cells in the draining lymph node increased their IFN{gamma} response. Together, these data suggest that IFN{gamma} production fluctuates based on cellular source and location, both of which could impact subsequent immune responses.

immunology↗

bioRxiv2022

Enhanced survival and low proliferation marks multifunctional virus specific memory CD4 T cells

Cytokine production by memory T cells is a key mechanism of T cell mediated protection. However, we have a limited understanding of the survival and secondary responses of memory T cells with cytokine producing capacities. We interrogate antigen-specific CD4 T cells using a mouse influenza A virus infection model. CD4 T cells with the capacity to produce cytokines survive better than non-cytokine+ cells, displaying a low fold contraction and expressing high levels of pro-survival molecules, CD127 and Bcl2. Transcriptomic analysis reveals a heterogenous population of memory CD4 T cells with three clusters of cytokine+ cells. These clusters match flow cytometry data revealing an enhanced survival signature in cells capable of producing multiple cytokines. These multifunctional cells are, however, less likely to proliferate during and following primary and secondary infections. Despite this, multifunctional memory T cells form a substantial fraction of the secondary memory pool, indicating that survival rather than proliferation may dictate which populations survive within the memory pool. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=86 SRC="FIGDIR/small/520219v3_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@93e62forg.highwire.dtl.DTLVardef@1ed2444org.highwire.dtl.DTLVardef@1e7f79borg.highwire.dtl.DTLVardef@30e31d_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

immunology↗