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Vickery JM, Toperzer JD, Raab JE, Lenz LL, Colgan SP, Russo BC. Synaptopodin is necessary for Shigella flexneri intercellular spread. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.25.537990. [PMID: 37163027 PMCID: PMC10168286 DOI: 10.1101/2023.04.25.537990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
For many intracellular pathogens, their virulence depends on an ability to spread between cells of an epithelial layer. For intercellular spread to occur, these pathogens deform the plasma membrane into a protrusion structure that is engulfed by the neighboring cell. Although the polymerization of actin is essential for spread, how these pathogens manipulate the actin cytoskeleton in a manner that enables protrusion formation is still incompletely understood. Here, we identify the mammalian actin binding protein synaptopodin as required for efficient intercellular spread. Using a model cytosolic pathogen, Shigella flexneri , we show that synaptopodin contributes to organization of actin around bacteria and increases the length of the actin tail at the posterior pole of the bacteria. We show that synaptopodin presence enables protrusions to form and to resolve at a greater rate, indicating that greater stability of the actin tail enables the bacteria to push against the membrane with greater force. We demonstrate that synaptopodin recruitment around bacteria requires the bacterial protein IcsA, and we show that this recruitment is further enhanced in a type 3 secretion system dependent manner. These data establish synaptopodin as required for intracellular bacteria to reprogram the actin cytoskeleton in a manner that enables efficient protrusion formation and enhance our understanding of the cellular function of synaptopodin. Authors Summary Intercellular spread is essential for many cytosolic dwelling pathogens during their infectious life cycle. Despite knowing the steps required for intercellular spread, relatively little is known about the host-pathogen interactions that enable these steps to occur. Here, we identify a requirement for the actin binding protein synaptopodin during intercellular spread by cytosolic bacteria. We show synaptopodin is necessary for the stability and recruitment of polymerized actin around bacteria. We also demonstrate synaptopodin is necessary to form plasma membrane structures known as protrusions that are necessary for the movement of these bacteria between cells. Thus, these findings implicate synaptopodin as an important actin-binding protein for the virulence of intracellular pathogens that require the actin cytoskeleton for their spread between cells.
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Remsik J, Tong X, Kunes RZ, Li MJ, Osman A, Chabot K, Sener UT, Wilcox JA, Isakov D, Snyder J, Bale TA, Chaligné R, Pe'er D, Boire A. Leptomeningeal anti-tumor immunity follows unique signaling principles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.533041. [PMID: 36993586 PMCID: PMC10055207 DOI: 10.1101/2023.03.17.533041] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Metastasis to the cerebrospinal fluid (CSF)-filled leptomeninges, or leptomeningeal metastasis (LM), represents a fatal complication of cancer. Proteomic and transcriptomic analyses of human CSF reveal a substantial inflammatory infiltrate in LM. We find the solute and immune composition of CSF in the setting of LM changes dramatically, with notable enrichment in IFN-γ signaling. To investigate the mechanistic relationships between immune cell signaling and cancer cells within the leptomeninges, we developed syngeneic lung, breast, and melanoma LM mouse models. Here we show that transgenic host mice, lacking IFN-γ or its receptor, fail to control LM growth. Overexpression of Ifng through a targeted AAV system controls cancer cell growth independent of adaptive immunity. Instead, leptomeningeal IFN-γ actively recruits and activates peripheral myeloid cells, generating a diverse spectrum of dendritic cell subsets. These migratory, CCR7+ dendritic cells orchestrate the influx, proliferation, and cytotoxic action of natural killer cells to control cancer cell growth in the leptomeninges. This work uncovers leptomeningeal-specific IFN-γ signaling and suggests a novel immune-therapeutic approach against tumors within this space.
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Boccuni L, Podgorschek E, Schmiedeberg M, Platanitis E, Traxler P, Fischer P, Schirripa A, Novoszel P, Nebreda AR, Arthur JSC, Fortelny N, Farlik M, Sexl V, Bock C, Sibilia M, Kovarik P, Müller M, Decker T. Stress signaling boosts interferon-induced gene transcription in macrophages. Sci Signal 2022; 15:eabq5389. [PMID: 36512641 DOI: 10.1126/scisignal.abq5389] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Promoters of antimicrobial genes function as logic boards, integrating signals of innate immune responses. One such set of genes is stimulated by interferon (IFN) signaling, and the expression of these genes [IFN-stimulated genes (ISGs)] can be further modulated by cell stress-induced pathways. Here, we investigated the global effect of stress-induced p38 mitogen-activated protein kinase (MAPK) signaling on the response of macrophages to IFN. In response to cell stress that coincided with IFN exposure, the p38 MAPK-activated transcription factors CREB and c-Jun, in addition to the IFN-activated STAT family of transcription factors, bound to ISGs. In addition, p38 MAPK signaling induced activating histone modifications at the loci of ISGs and stimulated nuclear translocation of the CREB coactivator CRTC3. These actions synergistically enhanced ISG expression. Disrupting this synergy with p38 MAPK inhibitors improved the viability of macrophages infected with Listeria monocytogenes. Our findings uncover a mechanism of transcriptional synergism and highlight the biological consequences of coincident stress-induced p38 MAPK and IFN-stimulated signal transduction.
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Affiliation(s)
- Laura Boccuni
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna 1030, Austria
- University of Vienna, Center for Molecular Biology, Department of Microbiology, Immunobiology and Genetics, Vienna 1030, Austria
| | - Elke Podgorschek
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna 1030, Austria
- University of Vienna, Center for Molecular Biology, Department of Microbiology, Immunobiology and Genetics, Vienna 1030, Austria
| | - Moritz Schmiedeberg
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna 1030, Austria
- University of Vienna, Center for Molecular Biology, Department of Microbiology, Immunobiology and Genetics, Vienna 1030, Austria
| | - Ekaterini Platanitis
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna 1030, Austria
- University of Vienna, Center for Molecular Biology, Department of Microbiology, Immunobiology and Genetics, Vienna 1030, Austria
| | - Peter Traxler
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna 1090, Austria
- Department of Dermatology, Medical University of Vienna, Vienna 1090, Austria
| | - Philipp Fischer
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna 1030, Austria
- University of Vienna, Center for Molecular Biology, Department of Microbiology, Immunobiology and Genetics, Vienna 1030, Austria
| | - Alessia Schirripa
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna 1210, Austria
| | - Philipp Novoszel
- Center for Cancer Research, Medical University of Vienna and Comprehensive Cancer Center, Vienna 1090, Austria
| | - Angel R Nebreda
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, Barcelona 08028, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona 08010, Spain
| | - J Simon C Arthur
- Division of Cell Signaling and Immunology and University of Dundee, Dow Street, Dundee DD1 5EH, UK
- Medical Research Council Protein Phosphorylation Unit, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Nikolaus Fortelny
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna 1090, Austria
- Computational Systems Biology Group, Department of Biosciences and Medical Biology, Paris Lodron University of Salzburg, Salzburg 5020, Austria
| | - Matthias Farlik
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna 1090, Austria
- Department of Dermatology, Medical University of Vienna, Vienna 1090, Austria
| | - Veronika Sexl
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna 1210, Austria
| | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna 1090, Austria
- Institute of Artificial Intelligence, Medical University of Vienna, Vienna 1090, Austria
| | - Maria Sibilia
- Center for Cancer Research, Medical University of Vienna and Comprehensive Cancer Center, Vienna 1090, Austria
| | - Pavel Kovarik
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna 1030, Austria
- University of Vienna, Center for Molecular Biology, Department of Microbiology, Immunobiology and Genetics, Vienna 1030, Austria
| | - Mathias Müller
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna 1210, Austria
| | - Thomas Decker
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna 1030, Austria
- University of Vienna, Center for Molecular Biology, Department of Microbiology, Immunobiology and Genetics, Vienna 1030, Austria
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