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Diallo A, Overman G, Sah P, Liechti GW. Recognition of Chlamydia trachomatis by Toll-like receptor 9 is altered during persistence. Infect Immun 2024; 92:e0006324. [PMID: 38899879 PMCID: PMC11238561 DOI: 10.1128/iai.00063-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Toll-like receptor 9 (TLR9) is an innate immune receptor that localizes to endosomes in antigen presenting cells and recognizes single stranded unmethylated CpG sites on bacterial genomic DNA (gDNA). Previous bioinformatic studies have demonstrated that the genome of the human pathogen Chlamydia trachomatis contains TLR9 stimulatory motifs, and correlative studies have implied a link between human TLR9 (hTLR9) genotype variants and susceptibility to infection. Here, we present our evaluation of the stimulatory potential of C. trachomatis gDNA and its recognition by hTLR9- and murine TLR9 (mTLR9)-expressing cells. Utilizing reporter cell lines, we demonstrate that purified gDNA from C. trachomatis can stimulate hTLR9 signaling, albeit at lower levels than gDNA prepared from other Gram-negative bacteria. Interestingly, we found that while C. trachomatis is capable of signaling through hTLR9 and mTLR9 during live infections in HEK293 reporter cell lines, signaling only occurs at later developmental time points. Chlamydia-specific induction of hTLR9 is blocked when protein synthesis is inhibited prior to the RB-to-EB conversion, exacerbated by the inhibition of lipooligosaccharide biosynthesis, and is significantly altered during the induction of aberrance/persistence. Our observations support the hypothesis that chlamydial gDNA is released during the conversion between the pathogen's replicative and infectious forms and during treatment with antibiotics targeting peptidoglycan assembly. Given that C. trachomatis inclusions do not co-localize with TLR9-containing vacuoles in the pro-monocytic cell line U937, our findings also hint that chlamydial gDNA is capable of egress from the inclusion, and traffics to TLR9-containing vacuoles via an as yet unknown pathway.
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Affiliation(s)
- Aissata Diallo
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
- Henry Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Grace Overman
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
- Henry Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Prakash Sah
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
- Henry Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - George W Liechti
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
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2
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Ren C, Wang Q, Fan S, Mi T, Zhang Z, He D. Toll-Like Receptor 9 Aggravates Pulmonary Fibrosis by Promoting NLRP3-Mediated Pyroptosis of Alveolar Epithelial Cells. Inflammation 2024:10.1007/s10753-024-02006-5. [PMID: 38498270 DOI: 10.1007/s10753-024-02006-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/13/2024] [Accepted: 03/13/2024] [Indexed: 03/20/2024]
Abstract
The apoptosis-prone property of alveolar epithelial cells plays a crucial role in pulmonary fibrosis(PF), but the role of pyroptosis in it is still unclear. Toll-like receptor 9(TLR9) has been reported to play a vital role in the pathogenesis of many diseases. However, the effect of TLR9 on alveolar epithelial cells in PF has not been fully elucidated. Gene expression microarray related to Idiopathic pulmonary fibrosis(IPF) was obtained from the Gene Expression Omnibus(GEO) database. In the mouse model of bleomycin-induced PF, adeno-associated virus(AAV6) was used to interfere with TLR9 to construct TLR9 knockdown mice to study the role of TLR9 in PF, and the specific mechanism was studied by intratracheal instillation of NLR family pyrin domain containing 3(NLRP3) activator. In vitro experiments were performed using A549 cells. Bleomycin-induced pyroptosis in the lung tissue of PF mice increased, and TLR9 protein levels also increased, especially in alveolar epithelial cells. The levels of fibrosis and pyroptosis in lung tissue of TLR9 knockdown mice were improved. We found that TLR9 can bind to the NLRP3, thereby increasing the activation of the NLRP3/caspase-1 inflammasome pathway. When we use the NLRP3 activator, the levels of fibrosis and pyroptosis in lung tissue of TLR9 knockout mice can be counteracted. Pyroptosis of alveolar epithelial cells plays a vital role in PF, and TLR9 can promote NLRP3-mediated pyroptosis of alveolar epithelial cells to aggravate the progression of PF and may become a feasible target for the prevention and treatment of PF.
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Affiliation(s)
- Chunnian Ren
- Department of Urology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child development and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
- Department of Cardiothoracic Surgery, Children's Hospital of Chongqing Medical University , National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
| | - Quan Wang
- Department of Cardiothoracic Surgery, Children's Hospital of Chongqing Medical University , National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
| | - Shulei Fan
- Department of Respiratory Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Tao Mi
- Department of Urology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child development and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
| | - Zhaoxia Zhang
- Department of Urology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child development and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China
| | - Dawei He
- Department of Urology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child development and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China.
- Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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3
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Diallo A, Overman G, Sah P, Liechti GW. Recognition of Chlamydia trachomatis by Toll-Like Receptor 9 is altered during persistence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579186. [PMID: 38370826 PMCID: PMC10871208 DOI: 10.1101/2024.02.06.579186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Toll-like receptor 9 (TLR9) is an innate immune receptor that localizes to endosomes in antigen presenting cells and recognizes single stranded unmethylated CpG sites on bacterial genomic DNA. Previous bioinformatic studies have indicated that the genome of the human pathogen Chlamydia trachomatis contains TLR9 stimulatory motifs, and correlative studies have implied a link between human TLR9 (hTLR9) genotype variants and susceptibility to infection. Here we present our evaluation of the stimulatory potential of C. trachomatis gDNA and its recognition by hTLR9- and murine TLR9 (mTLR9)-expressing cells. We confirm that hTLR9 colocalizes with chlamydial inclusions in the pro-monocytic cell line, U937. Utilizing HEK293 reporter cell lines, we demonstrate that purified genomic DNA from C. trachomatis can stimulate hTLR9 signaling, albeit at lower levels than gDNA prepared from other Gram-negative bacteria. Interestingly, we found that while C. trachomatis is capable of signaling through hTLR9 and mTLR9 during live infections in non-phagocytic HEK293 reporter cell lines, signaling only occurs at later developmental time points. Chlamydia-specific induction of hTLR9 is blocked when protein synthesis is inhibited prior to the RB-to-EB conversion and exacerbated by the inhibition of lipooligosaccharide biosynthesis. The induction of aberrance / persistence also significantly alters Chlamydia-specific TLR9 signaling. Our observations support the hypothesis that chlamydial gDNA is released at appreciable levels by the bacterium during the conversion between its replicative and infectious forms and during treatment with antibiotics targeting peptidoglycan assembly.
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Affiliation(s)
- Aissata Diallo
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, United States of America
- Henry Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States of America
| | - Grace Overman
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, United States of America
- Henry Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States of America
| | - Prakash Sah
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, United States of America
- Henry Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States of America
| | - George W. Liechti
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, United States of America
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4
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Reus P, Guthmann H, Uhlig N, Agbaria M, Issmail L, Eberlein V, Nordling-David MM, Jbara-Agbaria D, Ciesek S, Bojkova D, Cinatl J, Burger-Kentischer A, Rupp S, Zaliani A, Grunwald T, Gribbon P, Kannt A, Golomb G. Drug repurposing for the treatment of COVID-19: Targeting nafamostat to the lungs by a liposomal delivery system. J Control Release 2023; 364:654-671. [PMID: 37939853 DOI: 10.1016/j.jconrel.2023.10.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/10/2023]
Abstract
Despite tremendous global efforts since the beginning of the COVID-19 pandemic, still only a limited number of prophylactic and therapeutic options are available. Although vaccination is the most effective measure in preventing morbidity and mortality, there is a need for safe and effective post-infection treatment medication. In this study, we explored a pipeline of 21 potential candidates, examined in the Calu-3 cell line for their antiviral efficacy, for drug repurposing. Ralimetinib and nafamostat, clinically used drugs, have emerged as attractive candidates. Due to the inherent limitations of the selected drugs, we formulated targeted liposomes suitable for both systemic and intranasal administration. Non-targeted and targeted nafamostat liposomes (LipNaf) decorated with an Apolipoprotein B peptide (ApoB-P) as a specific lung-targeting ligand were successfully developed. The developed liposomal formulations of nafamostat were found to possess favorable physicochemical properties including nano size (119-147 nm), long-term stability of the normally rapidly degrading compound in aqueous solution, negligible leakage from the liposomes upon storage, and a neutral surface charge with low polydispersity index (PDI). Both nafamostat and ralimetinib liposomes showed good cellular uptake and lack of cytotoxicity, and non-targeted LipNaf demonstrated enhanced accumulation in the lungs following intranasal (IN) administration in non-infected mice. LipNaf retained its anti-SARS-CoV 2 activity in Calu 3 cells with only a modest decrease, exhibiting complete inhibition at concentrations >100 nM. IN, but not intraperitoneal (IP) treatment with targeted LipNaf resulted in a trend to reduced viral load in the lungs of K18-hACE2 mice compared to targeted empty Lip. Nevertheless, upon removal of outlier data, a statistically significant 1.9-fold reduction in viral load was achieved. This observation further highlights the importance of a targeted delivery into the respiratory tract. In summary, we were able to demonstrate a proof-of-concept of drug repurposing by liposomal formulations with anti-SARS-CoV-2 activity. The biodistribution and bioactivity studies with LipNaf suggest an IN or inhalation route of administration for optimal therapeutic efficacy.
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Affiliation(s)
- Philipp Reus
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Discovery Research ScreeningPort, Schnackenburgallee 114, 22525 Hamburg, Germany; Goethe University Frankfurt, University Hospital, Institute for Medical Virology, Paul-Ehrlich-Straße 40, 60596 Frankfurt am Main, Germany
| | - Hadar Guthmann
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Nadja Uhlig
- Fraunhofer Institute for Cell Therapy und Immunology IZI, Perlickstrasse 1, 04103 Leipzig, Germany
| | - Majd Agbaria
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Leila Issmail
- Fraunhofer Institute for Cell Therapy und Immunology IZI, Perlickstrasse 1, 04103 Leipzig, Germany
| | - Valentina Eberlein
- Fraunhofer Institute for Cell Therapy und Immunology IZI, Perlickstrasse 1, 04103 Leipzig, Germany
| | - Mirjam M Nordling-David
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Doaa Jbara-Agbaria
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Sandra Ciesek
- Goethe University Frankfurt, University Hospital, Institute for Medical Virology, Paul-Ehrlich-Straße 40, 60596 Frankfurt am Main, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Denisa Bojkova
- Goethe University Frankfurt, University Hospital, Institute for Medical Virology, Paul-Ehrlich-Straße 40, 60596 Frankfurt am Main, Germany
| | - Jindrich Cinatl
- Goethe University Frankfurt, University Hospital, Institute for Medical Virology, Paul-Ehrlich-Straße 40, 60596 Frankfurt am Main, Germany
| | - Anke Burger-Kentischer
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstraße 12, 70569 Stuttgart, Germany
| | - Steffen Rupp
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstraße 12, 70569 Stuttgart, Germany
| | - Andrea Zaliani
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Discovery Research ScreeningPort, Schnackenburgallee 114, 22525 Hamburg, Germany
| | - Thomas Grunwald
- Fraunhofer Institute for Cell Therapy und Immunology IZI, Perlickstrasse 1, 04103 Leipzig, Germany
| | - Philip Gribbon
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Discovery Research ScreeningPort, Schnackenburgallee 114, 22525 Hamburg, Germany
| | - Aimo Kannt
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany; Fraunhofer Innovation Center TheraNova, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany; Institute for Clinical Pharmacology, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany.
| | - Gershon Golomb
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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5
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Van Acker ZP, Perdok A, Hellemans R, North K, Vorsters I, Cappel C, Dehairs J, Swinnen JV, Sannerud R, Bretou M, Damme M, Annaert W. Phospholipase D3 degrades mitochondrial DNA to regulate nucleotide signaling and APP metabolism. Nat Commun 2023; 14:2847. [PMID: 37225734 DOI: 10.1038/s41467-023-38501-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 05/04/2023] [Indexed: 05/26/2023] Open
Abstract
Phospholipase D3 (PLD3) polymorphisms are linked to late-onset Alzheimer's disease (LOAD). Being a lysosomal 5'-3' exonuclease, its neuronal substrates remained unknown as well as how a defective lysosomal nucleotide catabolism connects to AD-proteinopathy. We identified mitochondrial DNA (mtDNA) as a major physiological substrate and show its manifest build-up in lysosomes of PLD3-defective cells. mtDNA accretion creates a degradative (proteolytic) bottleneck that presents at the ultrastructural level as a marked abundance of multilamellar bodies, often containing mitochondrial remnants, which correlates with increased PINK1-dependent mitophagy. Lysosomal leakage of mtDNA to the cytosol activates cGAS-STING signaling that upregulates autophagy and induces amyloid precursor C-terminal fragment (APP-CTF) and cholesterol accumulation. STING inhibition largely normalizes APP-CTF levels, whereas an APP knockout in PLD3-deficient backgrounds lowers STING activation and normalizes cholesterol biosynthesis. Collectively, we demonstrate molecular cross-talks through feedforward loops between lysosomal nucleotide turnover, cGAS-STING and APP metabolism that, when dysregulated, result in neuronal endolysosomal demise as observed in LOAD.
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Affiliation(s)
- Zoë P Van Acker
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Anika Perdok
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Ruben Hellemans
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Katherine North
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Inge Vorsters
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Cedric Cappel
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Jonas Dehairs
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Johannes V Swinnen
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Ragna Sannerud
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Marine Bretou
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Markus Damme
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium.
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium.
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6
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Kusiak A, Brady G. Bifurcation of signalling in human innate immune pathways to NF-kB and IRF family activation. Biochem Pharmacol 2022; 205:115246. [PMID: 36088989 DOI: 10.1016/j.bcp.2022.115246] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/28/2022]
Abstract
The human innate immune response can be activated through a wide range of stimuli. This multi-faceted system can be triggered by a range of immunostimulants including pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). These stimuli drive intracellular signalling pathways that branch off downstream to activate several distinct transcription factors. The two most impactful of which in innate immune outcomes are the NF-κB and the IRF family members. Both transcription factor families play defining roles in driving inflammation as well as the antiviral response. Pathways leading to their simultaneous activation share common upstream components but eventually distinct regulators which directly facilitate their activation. This review will discuss the current state of knowledge about what is known about how these pathways bifurcate to activate NF-κB and IRF family members.
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Affiliation(s)
- Aleksandra Kusiak
- Trinity Translational Medicine Institute, St James' Campus, Trinity College Dublin, D08 W9RT Dublin, Ireland.
| | - Gareth Brady
- Trinity Translational Medicine Institute, St James' Campus, Trinity College Dublin, D08 W9RT Dublin, Ireland.
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7
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Huérfano S, Šroller V, Bruštíková K, Horníková L, Forstová J. The Interplay between Viruses and Host DNA Sensors. Viruses 2022; 14:v14040666. [PMID: 35458396 PMCID: PMC9027975 DOI: 10.3390/v14040666] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/21/2022] [Accepted: 03/21/2022] [Indexed: 12/12/2022] Open
Abstract
DNA virus infections are often lifelong and can cause serious diseases in their hosts. Their recognition by the sensors of the innate immune system represents the front line of host defence. Understanding the molecular mechanisms of innate immunity responses is an important prerequisite for the design of effective antivirotics. This review focuses on the present state of knowledge surrounding the mechanisms of viral DNA genome sensing and the main induced pathways of innate immunity responses. The studies that have been performed to date indicate that herpesviruses, adenoviruses, and polyomaviruses are sensed by various DNA sensors. In non-immune cells, STING pathways have been shown to be activated by cGAS, IFI16, DDX41, or DNA-PK. The activation of TLR9 has mainly been described in pDCs and in other immune cells. Importantly, studies on herpesviruses have unveiled novel participants (BRCA1, H2B, or DNA-PK) in the IFI16 sensing pathway. Polyomavirus studies have revealed that, in addition to viral DNA, micronuclei are released into the cytosol due to genotoxic stress. Papillomaviruses, HBV, and HIV have been shown to evade DNA sensing by sophisticated intracellular trafficking, unique cell tropism, and viral or cellular protein actions that prevent or block DNA sensing. Further research is required to fully understand the interplay between viruses and DNA sensors.
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8
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Overexpression of toll-like receptors and co-stimulatory molecules on immature dendritic cells of Crohn's disease. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Bradshaw JL, Cushen SC, Phillips NR, Goulopoulou S. Circulating cell-free mitochondrial DNA in pregnancy. Physiology (Bethesda) 2022; 37:0. [PMID: 35001655 DOI: 10.1152/physiol.00037.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Circulating cell-free mitochondrial DNA (ccf-mtDNA) released upon cell injury or death stimulates diverse pattern recognition receptors to activate innate immune responses and initiate systemic inflammation. In this review, we discuss the temporal changes of ccf-mtDNA during pregnancy and its potential contribution to adverse pregnancy outcomes in pregnancy complications.
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Affiliation(s)
- Jessica L Bradshaw
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Spencer C Cushen
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States.,Texas College of Osteopathic Medicine, University of North Texas Health Science Center, Fort Worth, United States
| | - Nicole R Phillips
- Department of Microbiology, Immunology and Genetics, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Styliani Goulopoulou
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
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10
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Opichka MA, Rappelt MW, Gutterman DD, Grobe JL, McIntosh JJ. Vascular Dysfunction in Preeclampsia. Cells 2021; 10:3055. [PMID: 34831277 PMCID: PMC8616535 DOI: 10.3390/cells10113055] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 01/22/2023] Open
Abstract
Preeclampsia is a life-threatening pregnancy-associated cardiovascular disorder characterized by hypertension and proteinuria at 20 weeks of gestation. Though its exact underlying cause is not precisely defined and likely heterogenous, a plethora of research indicates that in some women with preeclampsia, both maternal and placental vascular dysfunction plays a role in the pathogenesis and can persist into the postpartum period. Potential abnormalities include impaired placentation, incomplete spiral artery remodeling, and endothelial damage, which are further propagated by immune factors, mitochondrial stress, and an imbalance of pro- and antiangiogenic substances. While the field has progressed, current gaps in knowledge include detailed initial molecular mechanisms and effective treatment options. Newfound evidence indicates that vasopressin is an early mediator and biomarker of the disorder, and promising future therapeutic avenues include mitigating mitochondrial dysfunction, excess oxidative stress, and the resulting inflammatory state. In this review, we provide a detailed overview of vascular defects present during preeclampsia and connect well-established notions to newer discoveries at the molecular, cellular, and whole-organism levels.
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Affiliation(s)
- Megan A. Opichka
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (M.A.O.); (D.D.G.); (J.L.G.)
| | - Matthew W. Rappelt
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
| | - David D. Gutterman
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (M.A.O.); (D.D.G.); (J.L.G.)
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Justin L. Grobe
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (M.A.O.); (D.D.G.); (J.L.G.)
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jennifer J. McIntosh
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (M.A.O.); (D.D.G.); (J.L.G.)
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
- Department of Obstetrics and Gynecology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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11
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Lasola JJM, Cottingham AL, Scotland BL, Truong N, Hong CC, Shapiro P, Pearson RM. Immunomodulatory Nanoparticles Mitigate Macrophage Inflammation via Inhibition of PAMP Interactions and Lactate-Mediated Functional Reprogramming of NF-κB and p38 MAPK. Pharmaceutics 2021; 13:1841. [PMID: 34834256 PMCID: PMC8618039 DOI: 10.3390/pharmaceutics13111841] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/23/2021] [Accepted: 10/28/2021] [Indexed: 12/29/2022] Open
Abstract
Inflammation is a key homeostatic process involved in the body's response to a multitude of disease states including infection, autoimmune disorders, cancer, and other chronic conditions. When the initiating event is poorly controlled, severe inflammation and globally dysregulated immune responses can occur. To address the lack of therapies that efficaciously address the multiple aspects of the dysregulated immune response, we developed cargo-less immunomodulatory nanoparticles (iNPs) comprised of poly(lactic acid) (PLA) with either poly(vinyl alcohol) (PVA) or poly(ethylene-alt-maleic acid) (PEMA) as stabilizing surfactants and investigated the mechanisms by which they exert their inherent anti-inflammatory effects. We identified that iNPs leverage a multimodal mechanism of action by physically interfering with the interactions between pathogen-associated molecular patterns (PAMPs) and bone marrow-derived macrophages (BMMΦs). Additionally, we showed that iNPs mitigate proinflammatory cytokine secretions induced by LPS via a time- and composition-dependent abrogation of NF-κB p65 and p38 MAPK activation. Lastly, inhibition studies were performed to establish the role of a pH-sensing G-protein-coupled receptor, GPR68, on contributing to the activity of iNPs. These data provide evidence for the multimodal mechanism of action of iNPs and establish their potential use as a novel therapeutic for the treatment of severe inflammation.
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Affiliation(s)
- Jackline Joy Martín Lasola
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore Street, Baltimore, MD 21201, USA;
| | - Andrea L. Cottingham
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine Street, Baltimore, MD 21201, USA; (A.L.C.); (B.L.S.); (N.T.); (P.S.)
| | - Brianna L. Scotland
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine Street, Baltimore, MD 21201, USA; (A.L.C.); (B.L.S.); (N.T.); (P.S.)
| | - Nhu Truong
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine Street, Baltimore, MD 21201, USA; (A.L.C.); (B.L.S.); (N.T.); (P.S.)
| | - Charles C. Hong
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, 110 S. Paca Street, Baltimore, MD 21201, USA;
| | - Paul Shapiro
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine Street, Baltimore, MD 21201, USA; (A.L.C.); (B.L.S.); (N.T.); (P.S.)
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, 22 S. Greene Street, Baltimore, MD 21201, USA
| | - Ryan M. Pearson
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 N. Pine Street, Baltimore, MD 21201, USA; (A.L.C.); (B.L.S.); (N.T.); (P.S.)
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, 22 S. Greene Street, Baltimore, MD 21201, USA
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12
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Dubový P, Hradilová-Svíženská I, Brázda V, Joukal M. Toll-Like Receptor 9-Mediated Neuronal Innate Immune Reaction Is Associated with Initiating a Pro-Regenerative State in Neurons of the Dorsal Root Ganglia Non-Associated with Sciatic Nerve Lesion. Int J Mol Sci 2021; 22:ijms22147446. [PMID: 34299065 PMCID: PMC8304752 DOI: 10.3390/ijms22147446] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 12/27/2022] Open
Abstract
One of the changes brought about by Wallerian degeneration distal to nerve injury is disintegration of axonal mitochondria and consequent leakage of mitochondrial DNA (mtDNA)—the natural ligand for the toll-like receptor 9 (TLR9). RT-PCR and immunohistochemical or Western blot analyses were used to detect TLR9 mRNA and protein respectively in the lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) ipsilateral and contralateral to a sterile unilateral sciatic nerve compression or transection. The unilateral sciatic nerve lesions led to bilateral increases in levels of both TLR9 mRNA and protein not only in the lumbar but also in the remote cervical DRG compared with naive or sham-operated controls. This upregulation of TLR9 was linked to activation of the Nuclear Factor kappa B (NFκB) and nuclear translocation of the Signal Transducer and Activator of Transcription 3 (STAT3), implying innate neuronal immune reaction and a pro-regenerative state in uninjured primary sensory neurons of the cervical DRG. The relationship of TLR9 to the induction of a pro-regenerative state in the cervical DRG neurons was confirmed by the shorter lengths of regenerated axons distal to ulnar nerve crush following a previous sciatic nerve lesion and intrathecal chloroquine injection compared with control rats. The results suggest that a systemic innate immune reaction not only triggers the regenerative state of axotomized DRG neurons but also induces a pro-regenerative state further along the neural axis after unilateral nerve injury.
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13
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Amadio R, Piperno GM, Benvenuti F. Self-DNA Sensing by cGAS-STING and TLR9 in Autoimmunity: Is the Cytoskeleton in Control? Front Immunol 2021; 12:657344. [PMID: 34084165 PMCID: PMC8167430 DOI: 10.3389/fimmu.2021.657344] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/06/2021] [Indexed: 12/11/2022] Open
Abstract
Modified or misplaced DNA can be recognized as a danger signal by mammalian cells. Activation of cellular responses to DNA has evolved as a defense mechanism to microbial infections, cellular stress, and tissue damage, yet failure to control this mechanism can lead to autoimmune diseases. Several monogenic and multifactorial autoimmune diseases have been associated with type-I interferons and interferon-stimulated genes (ISGs) induced by deregulated recognition of self-DNA. Hence, understanding how cellular mechanism controls the pathogenic responses to self-nucleic acid has important clinical implications. Fine-tuned membrane trafficking and cellular compartmentalization are two major factors that balance activation of DNA sensors and availability of self-DNA ligands. Intracellular transport and organelle architecture are in turn regulated by cytoskeletal dynamics, yet the precise impact of actin remodeling on DNA sensing remains elusive. This review proposes a critical analysis of the established and hypothetical connections between self-DNA recognition and actin dynamics. As a paradigm of this concept, we discuss recent evidence of deregulated self-DNA sensing in the prototypical actin-related primary immune deficiency (Wiskott-Aldrich syndrome). We anticipate a broader impact of actin-dependent processes on tolerance to self-DNA in autoimmune disorders.
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Affiliation(s)
- Roberto Amadio
- Cellular Immunology, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
- Department of Biomedical Sciences, Venetian Institute of Molecular Medicine, University of Padova, Padova, Italy
| | - Giulia Maria Piperno
- Cellular Immunology, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Federica Benvenuti
- Cellular Immunology, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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14
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Song B, Liu D, Greco TM, Cristea IM. Post-translational modification control of viral DNA sensors and innate immune signaling. Adv Virus Res 2021; 109:163-199. [PMID: 33934827 PMCID: PMC8489191 DOI: 10.1016/bs.aivir.2021.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The vertebrate innate immune system confers host cells with mechanisms to protect against both evolutionarily ancient pathogens and newly emerging pathogenic strains. Innate immunity relies on the host cell's ability to distinguish between self and pathogen-derived molecules. To achieve this, the innate immune system uses germline encoded receptors called pattern recognition receptors (PRRs), which recognize various molecular signatures, including nucleic acids, proteins, lipids, glycans and glycolipids. Among these molecules, the recognition of pathogenic, mislocalized, or damaged DNA by cellular protein receptors, commonly called DNA sensors, represents a major surveillance pathway for initiating immune signaling. The ability of cells to temporally regulate DNA sensor activation and subsequent signal termination is critical for effective immune signaling. These same mechanisms are also co-opted by pathogens to promote their replication. Therefore, there is significant interest in understanding DNA sensor regulatory networks during microbial infections and autoimmune disease. One emerging aspect of DNA sensor regulation is through post-translational modifications (PTMs), including phosphorylation, acetylation, ubiquitination, ADP-ribosylation, SUMOylation, methylation, deamidation, glutamylation. In this chapter, we discuss how PTMs have been shown to positively or negatively impact DNA sensor functions via diverse mechanisms, including direct regulation of enzymatic activity, protein-protein and protein-DNA interactions, protein translocations and protein turnover. In addition, we highlight the ability of virus-induced PTMs to promote immune evasion. We also discuss the recent evidence linking PTMs on DNA sensors with human diseases and more broadly, highlight promising directions for future research on PTM-mediated regulation of DNA sensor-dependent immune signaling.
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Affiliation(s)
- Bokai Song
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Dawei Liu
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Todd M Greco
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States.
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15
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Karapetyan L, Luke JJ, Davar D. Toll-Like Receptor 9 Agonists in Cancer. Onco Targets Ther 2020; 13:10039-10060. [PMID: 33116588 PMCID: PMC7553670 DOI: 10.2147/ott.s247050] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/16/2020] [Indexed: 12/19/2022] Open
Abstract
Toll-like receptor 9 (TLR9) is a pattern recognition receptor that is predominantly located intracellularly in immune cells, including dendritic cells, macrophages, natural killer cells, and other antigen-presenting cells (APC). The primary ligands for TLR9 receptors are unmethylated cytidine phosphate guanosine (CpG) oligodinucleotides (ODN). TLR9 agonists induce inflammatory processes that result in the enhanced uptake and killing of microorganisms and cancer cells as well as the generation of adaptive immune responses. Preclinical studies of TLR9 agonists suggested efficacy both as monotherapy and in combination with several agents, which led to clinical trials in patients with advanced cancer. In these studies, intravenous, intratumoral, and subcutaneous routes of administration have been tested; with anti-tumor responses in both treated and untreated metastatic sites. TLR9 agonist monotherapy is safe, although efficacy is minimal in advanced cancer patients; conversely, combinations appear to be more promising. Several ongoing phase I and II clinical trials are evaluating TLR9 agonists in combination with a variety of agents including chemotherapy, radiotherapy, targeted therapy, and immunotherapy agents. In this review article, we describe the distribution, structure and signaling of TLR9; discuss the results of preclinical studies of TLR9 agonists; and review ongoing clinical trials of TLR9 agonists singly and in combination in patients with advanced solid tumors.
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Affiliation(s)
- Lilit Karapetyan
- University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center (HCC), Pittsburgh, PA, USA
| | - Jason J Luke
- University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center (HCC), Pittsburgh, PA, USA.,Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Diwakar Davar
- University of Pittsburgh Medical Center (UPMC) Hillman Cancer Center (HCC), Pittsburgh, PA, USA.,Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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16
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Justina VD, Giachini FR, Sullivan JC, Webb RC. Toll-Like Receptors Contribute to Sex Differences in Blood Pressure Regulation. J Cardiovasc Pharmacol 2020; 76:255-266. [PMID: 32902942 PMCID: PMC7751064 DOI: 10.1097/fjc.0000000000000869] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Toll-like receptors (TLRs) play an important role in the innate immune system, and recently, they have been shown to be involved in the regulation of blood pressure. The incidence of hypertension is higher in men, and it increases in postmenopausal women. In fact, premenopausal women are protected from cardiovascular disease compared with age-matched men, and it is well established that this protective effect is lost with menopause. However, the molecular mechanisms underlying this protection in women are unknown. Whether or not it could be related to differential activation of the innate immune system remains to be elucidated. This review focuses on (1) the differences between men and women in TLR activation and (2) whether TLR activation may influence the regulation of blood pressure in a sex-dependent manner.
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Affiliation(s)
- Vanessa Dela Justina
- Graduate Program in Biological Sciences, Federal University of Goiás, Goiânia, Brazil
| | - Fernanda R. Giachini
- Graduate Program in Biological Sciences, Federal University of Goiás, Goiânia, Brazil
- Institute of Health Sciences and Health, Universidad Federal De Mato Grosso, Barra Do Garcas, Brazil
| | - Jennifer C. Sullivan
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA
| | - R. Clinton Webb
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA
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17
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Gruber EJ, Leifer CA. Molecular regulation of TLR signaling in health and disease: mechano-regulation of macrophages and TLR signaling. Innate Immun 2020; 26:15-25. [PMID: 31955624 PMCID: PMC6974875 DOI: 10.1177/1753425919838322] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 12/28/2022] Open
Abstract
Immune cells encounter tissues with vastly different biochemical and physical characteristics. Much of the research emphasis has focused on the role of cytokines and chemokines in regulating immune cell function, but the role of the physical microenvironment has received considerably less attention. The tissue mechanics, or stiffness, of healthy tissues varies dramatically from soft adipose tissue and brain to stiff cartilage and bone. Tissue mechanics also change due to fibrosis and with diseases such as atherosclerosis or cancer. The process by which cells sense and respond to their physical microenvironment is called mechanotransduction. Here we review mechanotransduction in immunologically important diseases and how physical characteristics of tissues regulate immune cell function, with a specific emphasis on mechanoregulation of macrophages and TLR signaling.
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Affiliation(s)
| | - Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell
University, Ithaca, NY, USA
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18
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Affiliation(s)
- Cameron G McCarthy
- From the Center for Hypertension and Personalized Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, OH (C.G.M.)
| | - Styliani Goulopoulou
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth (S.G.)
| | - R Clinton Webb
- Department of Physiology, Augusta University, GA (R.C.W.)
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19
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Toll-like receptor 9 antagonism modulates astrocyte function and preserves proximal axons following spinal cord injury. Brain Behav Immun 2019; 80:328-343. [PMID: 30953770 DOI: 10.1016/j.bbi.2019.04.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 03/14/2019] [Accepted: 04/02/2019] [Indexed: 02/07/2023] Open
Abstract
Increasing evidence indicates that innate immune receptors play important, yet controversial, roles in traumatic central nervous system (CNS) injury. Despite many advances, the contributions of toll-like receptors (TLRs) to spinal cord injury (SCI) remain inadequately defined. We previously reported that a toll-like receptor 9 (TLR9) antagonist, oligodeoxynucleotide 2088 (ODN 2088), administered intrathecally, improves the functional and histopathological outcomes of SCI. However, the molecular and cellular changes that occur at the injury epicenter following ODN 2088 treatment are not completely understood. Following traumatic SCI, a glial scar, consisting primarily of proliferating reactive astrocytes, forms at the injury epicenter and assumes both beneficial and detrimental roles. Increased production of chondroitin sulfate proteoglycans (CSPGs) by reactive astrocytes inhibits the regeneration of injured axons. Astrocytes express TLR9, which can be activated by endogenous ligands released by damaged cells. It is not yet known how TLR9 antagonism modifies astrocyte function at the glial scar and how this affects axonal preservation or re-growth following SCI. The present studies were undertaken to address these issues. We report that in female mice sustaining a severe mid-thoracic (T8) contusion injury, the number of proliferating astrocytes in regions rostral and caudal to the lesion border increased significantly by 30- and 24-fold, respectively, compared to uninjured controls. Intrathecal ODN 2088 treatment significantly reduced the number of proliferating astrocytes by 60% in both regions. This effect appeared to be, at least partly, mediated through the direct actions of ODN 2088 on astrocytes, since the antagonist decreased proliferation in pure SC astrocyte cultures by preventing the activation of the Erk/MAPK signaling pathway. In addition, CSPG immunoreactivity at the lesion border was more pronounced in vehicle-treated injured mice compared to uninjured controls and was significantly reduced following administration of ODN 2088 to injured mice. Moreover, ODN 2088 significantly decreased astrocyte migration in an in vitro scratch-wound assay. Anterograde tracing and quantification of corticospinal tract (CST) axons in injured mice, indicated that ODN 2088 preserves proximal axons. Taken together, these findings suggest that ODN 2088 modifies the glial scar and creates a milieu that fosters axonal protection at the injury site.
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20
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Wu H, Zhuang Q, Xu J, Xu L, Zhao Y, Wang C, Yang Z, Shen F, Liu Z, Peng R. Cell-Penetrating Peptide Enhanced Antigen Presentation for Cancer Immunotherapy. Bioconjug Chem 2019; 30:2115-2126. [DOI: 10.1021/acs.bioconjchem.9b00245] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Hanfei Wu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Qi Zhuang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Jun Xu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Ligeng Xu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Yuhuan Zhao
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Chenya Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Zongjin Yang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Fengyun Shen
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Zhuang Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
| | - Rui Peng
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren’ai Rd, Suzhou, Jiangsu 215123, P. R. China
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21
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Gruber E, Heyward C, Cameron J, Leifer C. Toll-like receptor signaling in macrophages is regulated by extracellular substrate stiffness and Rho-associated coiled-coil kinase (ROCK1/2). Int Immunol 2019; 30:267-278. [PMID: 29800294 DOI: 10.1093/intimm/dxy027] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 04/04/2018] [Indexed: 02/07/2023] Open
Abstract
Macrophages participate in immunity, tissue repair and tissue homeostasis. Activation of Toll-like receptors (TLRs) by conserved exogenous or endogenous structures initiates signaling cascades that result in the release of cytokines such as tumor necrosis factor α (TNFα). Extracellular substrate stiffness is known to regulate functions of non-immune cells through a process called mechanotransduction, yet less is known about how physical cues affect macrophage function or TLR signaling. To investigate this question, we cultured murine primary bone marrow-derived macrophages (BMMs) and RAW264.7 cells on fibronectin-coated polyacrylamide (PA) gels of defined stiffnesses (1, 20 and 150 kPa) that approximate the physical properties of physiologic tissues. BMMs on all gels were smaller and more circular than those on rigid glass. Macrophages on intermediate stiffness 20 kPa PA gels were slightly larger and less circular than those on either 1 or 150 kPa. Secretion of the pro-inflammatory cytokine, TNFα, in response to stimulation of TLR4 and TLR9 was increased in macrophages grown on soft gels versus more rigid gels, particularly for BMMs. Inhibition of the rho-associated coiled-coil kinase 1/2 (ROCK1/2), key mediators in cell contractility and mechanotransduction, enhanced release of TNFα in response to stimulation of TLR4. ROCK1/2 inhibition enhanced phosphorylation of the TLR downstream signaling molecules, p38, ERK1/2 and NFκB. Our data indicate that physical cues from the extracellular environment regulate macrophage morphology and TLR signaling. These findings have important implications in the regulation of macrophage function in diseased tissues and offer a novel pharmacological target for the manipulation of macrophage function in vivo.
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Affiliation(s)
- Erika Gruber
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Christa Heyward
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Jody Cameron
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Cynthia Leifer
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
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22
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Abstract
Mitochondria are the source of damage-associated molecular patterns (DAMPs), which are molecules that play a key modulatory role in immune cells. These molecules include proteins and peptides, such as N-formyl peptides and TFAM, as well as lipids, and metabolites such as cardiolipin, succinate and ATP, and also mitochondrial DNA (mtDNA). Recent data indicate that somatic cells sense mitochondrial DAMPs and trigger protective mechanisms in response to these signals. In this review we focus on the well-described effects of mitochondrial DAMPs on immune cells and also how these molecules induce immunogenic responses in non-immune cells. Special attention will be paid to the response to mtDNA.
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Affiliation(s)
- Aida Rodríguez-Nuevo
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain.,Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, 08028 Barcelona, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain.,Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, 08028 Barcelona, Spain.,CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III
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23
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Sauter IP, Madrid KG, de Assis JB, Sá-Nunes A, Torrecilhas AC, Staquicini DI, Pasqualini R, Arap W, Cortez M. TLR9/MyD88/TRIF signaling activates host immune inhibitory CD200 in Leishmania infection. JCI Insight 2019; 4:126207. [PMID: 31092731 DOI: 10.1172/jci.insight.126207] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 04/11/2019] [Indexed: 02/06/2023] Open
Abstract
Virulent protozoans named Leishmania in tropical and subtropical areas produce devastating diseases by exploiting host immune responses. Amastigotes of Leishmania amazonensis stimulate macrophages to express CD200, an immunomodulatory ligand, which binds to its cognate receptor (CD200R) and inhibits the inducible nitric oxide synthase and nitric oxide (iNOS/NO) signaling pathways, thereby promoting intracellular survival. However, the mechanisms underlying CD200 induction in macrophages remain largely unknown. Here, we show that phagocytosis-mediated internalization of L. amazonensis amastigotes following activation of endosomal TLR9/MyD88/TRIF signaling is critical for inducing CD200 in infected macrophages. We also demonstrate that Leishmania microvesicles containing DNA fragments activate TLR9-dependent CD200 expression, which inhibits the iNOS/NO pathway and modulates the course of L. amazonensis infection in vivo. These findings demonstrate that Leishmania exploits TLR-signaling pathways not only to inhibit macrophage microbicidal function, but also to evade host systemic immune responses, which has many implications in the severity of the disease.
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Affiliation(s)
| | | | - Josiane B de Assis
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Anderson Sá-Nunes
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ana C Torrecilhas
- Department of Pharmaceutical Sciences, Federal University of São Paulo, São Paulo, Brazil
| | - Daniela I Staquicini
- Rutgers Cancer Institute of New Jersey and Division of Cancer Biology, Department of Radiation Oncology, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Renata Pasqualini
- Rutgers Cancer Institute of New Jersey and Division of Cancer Biology, Department of Radiation Oncology, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Wadih Arap
- Rutgers Cancer Institute of New Jersey and Division of Hematology/Oncology, Department of Medicine, Rutgers New Jersey Medical School, Newark, New Jersey, USA
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24
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Inhibition of TLR9 attenuates skeletal muscle fibrosis in aged sarcopenic mice via the p53/SIRT1 pathway. Exp Gerontol 2019; 122:25-33. [PMID: 31003004 DOI: 10.1016/j.exger.2019.04.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/03/2019] [Accepted: 04/15/2019] [Indexed: 01/08/2023]
Abstract
Sarcopenia is an age-related syndrome characterized by a gradual loss of muscle mass and function, but its pathophysiological mechanism remains unclear. Skeletal muscle extracellular matrix (ECM) remodeling is an important pathological change in sarcopenia, and fibrosis is the most obvious manifestation of this change. We found that the expression of the immunoreceptor Toll-like receptor 9 (TLR9) is significantly increased in skeletal muscle in aged mice and is positively related to muscle fibrosis. Moreover, in previous reports, the longevity gene Sirt1 was reported to attenuate ECM deposition and improve muscle function. In this study, we hypothesized that TLR9 modulated skeletal muscle fibrosis via Sirt1. We used TLR9 knockout (TLR9 KO) mice and C57 mice, and grip strength and body composition were compared at different ages. We found that TLR9 knockout significantly attenuated skeletal muscle fibrosis and improved muscle function in aged mice. Furthermore, silent information regulator 1 (Sirt1) activity in mice was inhibited by Ex527, which is a specific inhibitor of Sirt1. Negative Sirt1 regulation via the activation of TLR9-related signaling pathways participated in skeletal muscle fibrosis in the sarcopenic mice, and this process might mediated by the Sirt1/Smad signaling pathway. Our findings revealed that fibrosis changes in the gastrocnemius muscle in sarcopenic mice are closely related to TLR9 activation, and TLR9 modulation could be a therapeutic strategy for combating sarcopenia during aging.
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25
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Embryonic Neocortical Microglia Express Toll-Like Receptor 9 and Respond to Plasmid DNA Injected into the Ventricle: Technical Considerations Regarding Microglial Distribution in Electroporated Brain Walls. eNeuro 2018; 5:eN-MNT-0312-18. [PMID: 30627652 PMCID: PMC6325556 DOI: 10.1523/eneuro.0312-18.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/19/2018] [Accepted: 10/27/2018] [Indexed: 12/25/2022] Open
Abstract
Microglia, the resident immune cells in the CNS, play multiple roles during development. In the embryonic cerebral wall, microglia modulate the functions of neural stem/progenitor cells through their distribution in regions undergoing cell proliferation and/or differentiation. Previous studies using CX3CR1-GFP transgenic mice demonstrated that microglia extensively survey these regions. To simultaneously visualize microglia and neural-lineage cells that interact with each other, we applied the in utero electroporation (IUE) technique, which has been widely used for gene-transfer in neurodevelopmental studies, to CX3CR1-GFP mice (males and females). However, we unexpectedly faced a technical problem: although microglia are normally distributed homogeneously throughout the mid-embryonic cortical wall with only limited luminal entry, the intraventricular presence of exogenously derived plasmid DNAs induced microglia to accumulate along the apical surface of the cortex and aggregate in the choroid plexus. This effect was independent of capillary needle puncture of the brain wall or application of electrical pulses. The microglial response occurred at plasmid DNA concentrations lower than those routinely used for IUE, and was mediated by activation of Toll-like receptor 9 (TLR9), an innate immune sensor that recognizes unmethylated cytosine-phosphate guanosine motifs abundant in microbial DNA. Administration of plasmid DNA together with oligonucleotide 2088, the antagonist of TLR9, partially restored the dispersed intramural localization of microglia and significantly decreased luminal accumulation of these cells. Thus, via TLR9, intraventricular plasmid DNA administration causes aberrant distribution of embryonic microglia, suggesting that the behavior of microglia in brain primordia subjected to IUE should be carefully interpreted.
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26
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Garcia-Carmona Y, Ting AT, Radigan L, Athuluri Divakar SK, Chavez J, Meffre E, Cerutti A, Cunningham-Rundles C. TACI Isoforms Regulate Ligand Binding and Receptor Function. Front Immunol 2018; 9:2125. [PMID: 30333819 PMCID: PMC6176016 DOI: 10.3389/fimmu.2018.02125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/29/2018] [Indexed: 12/12/2022] Open
Abstract
TACI signals activate B cell proliferation, isotype switch and antibody production in both normal immunity and autoimmune states. In contrast to murine TACI, the human TACI gene undergoes alternative splicing to produce short and long isoforms (TACI-S and TACI-L). In previous studies, we showed that transduction of the short, but not long isoform, into murine B cells or human pre-B cells lacking TACI, caused them to become transcriptional and morphologically identical to plasma cells. These data suggest that the expression of different isoforms in humans provides unique controls on B cell maturation. In these studies we show that TACI-S and TACI-L form complexes in a ligand-independent manner, not dependent on a single extracellular domain. Both TACI isoforms are detectable in the endosomal cellular compartment where they co-localize with MyD88, TRAF6, and the activated 65 kDa form of TLR9, depending on a conserved intracellular TACI sequence. In contrast to TACI-L expressing cells, or cells bearing both isoforms, TACI-S binds ligands BAFF and APRIL with substantially greater affinity and promotes enhanced NF-kB activation. Using isoform-specific monoclonal antibodies, we show that while TACI-L is predominant as a surface receptor surface on human B cells, significantly more TACI-S is noted in the intracellular compartment and also in marginal zone, isotype switched and plasmablast in resting B cells. TACI-S is increased in tonsillar B cells and also in the intracellular compartment of activated peripheral B cells. These data shows that alternative splicing of the human TACI gene leads to two isoforms both of which intersect with MyD88 and TRAF6 and form complexes with TLR9, but the two isoforms have different ligand binding capacities, subcellular locations and activation capabilities.
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Affiliation(s)
- Yolanda Garcia-Carmona
- Department of Clinical Immunology, Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Adrian T Ting
- Department of Clinical Immunology, Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Lin Radigan
- Department of Clinical Immunology, Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | | | - Jose Chavez
- Department of Clinical Immunology, Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Eric Meffre
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, United States
| | - Andrea Cerutti
- Department of Clinical Immunology, Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Catalan Institute for Research and Advance Studies (ICREA), Barcelona, Spain.,Program for Inflammatory and Cardiovascular Disorders, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
| | - Charlotte Cunningham-Rundles
- Department of Clinical Immunology, Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Medicine and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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27
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Tan X, Sun L, Chen J, Chen ZJ. Detection of Microbial Infections Through Innate Immune Sensing of Nucleic Acids. Annu Rev Microbiol 2018; 72:447-478. [DOI: 10.1146/annurev-micro-102215-095605] [Citation(s) in RCA: 221] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microbial infections are recognized by the innate immune system through germline-encoded pattern recognition receptors (PRRs). As most microbial pathogens contain DNA and/or RNA during their life cycle, nucleic acid sensing has evolved as an essential strategy for host innate immune defense. Pathogen-derived nucleic acids with distinct features are recognized by specific host PRRs localized in endolysosomes and the cytosol. Activation of these PRRs triggers signaling cascades that culminate in the production of type I interferons and proinflammatory cytokines, leading to induction of an antimicrobial state, activation of adaptive immunity, and eventual clearance of the infection. Here, we review recent progress in innate immune recognition of nucleic acids upon microbial infection, including pathways involving endosomal Toll-like receptors, cytosolic RNA sensors, and cytosolic DNA sensors. We also discuss the mechanisms by which infectious microbes counteract host nucleic acid sensing to evade immune surveillance.
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Affiliation(s)
- Xiaojun Tan
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Lijun Sun
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
| | - Jueqi Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Zhijian J. Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA;, , , ,
- Center for Inflammation Research, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
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28
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Uyangaa E, Choi JY, Patil AM, Hossain FMA, Park SO, Kim B, Kim K, Eo SK. Dual TLR2/9 Recognition of Herpes Simplex Virus Infection Is Required for Recruitment and Activation of Monocytes and NK Cells and Restriction of Viral Dissemination to the Central Nervous System. Front Immunol 2018; 9:905. [PMID: 29760708 PMCID: PMC5936768 DOI: 10.3389/fimmu.2018.00905] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 04/11/2018] [Indexed: 12/24/2022] Open
Abstract
The importance of TLR2 and TLR9 in the recognition of infection with herpes simplex virus (HSV) and HSV-caused diseases has been described, but some discrepancies remain concerning the benefits of these responses. Moreover, the impact of TLR2/9 on innate and adaptive immune responses within relevant mucosal tissues has not been elucidated using natural mucosal infection model of HSV. Here, we demonstrate that dual TLR2/9 recognition is essential to provide resistance against mucosal infection with HSV via an intravaginal route. Dual TLR2/9 ablation resulted in the highly enhanced mortality with exacerbated symptoms of encephalitis compared with TLR2 or TLR9 deficiency alone, coinciding with highly increased viral load in central nervous system tissues. TLR2 appeared to play a minor role in providing resistance against mucosal infection with HSV, since TLR2-ablated mice showed higher survival rate compared with TLR9-ablated mice. Also, the high mortality in dual TLR2/9-ablated mice was closely associated with the reduction in early monocyte and NK cell infiltration in the vaginal tract (VT), which was likely to correlate with low expression of cytokines and CCR2 ligands (CCL2 and CCL7). More interestingly, our data revealed that dual TLR2/9 recognition of HSV infection plays an important role in the functional maturation of TNF-α and iNOS-producing dendritic cells (Tip-DCs) from monocytes as well as NK cell activation in VT. TLR2/9-dependent maturation of Tip-DCs from monocytes appeared to specifically present cognate Ag, which effectively provided functional effector CD4+ and CD8+ T cells specific for HSV Ag in VT and its draining lymph nodes. TLR2/9 expressed in monocytes was likely to directly facilitate Tip-DC-like features after HSV infection. Also, dual TLR2/9 recognition of HSV infection directly activated NK cells without the aid of dendritic cells through activation of p38 MAPK pathway. Taken together, these results indicate that dual TLR2/9 recognition plays a critical role in providing resistance against mucosal infection with HSV, which may involve a direct regulation of Tip-DCs and NK cells in VT. Therefore, our data provide a more detailed understanding of TLR2/9 role in conferring antiviral immunity within relevant mucosal tissues after mucosal infection with HSV.
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Affiliation(s)
- Erdenebileg Uyangaa
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, South Korea
| | - Jin Young Choi
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, South Korea
| | - Ajit Mahadev Patil
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, South Korea
| | - Ferdaus Mohd Altaf Hossain
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, South Korea.,Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet, Bangladesh
| | - Sung Ok Park
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, South Korea
| | - Bumseok Kim
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, South Korea
| | - Koanhoi Kim
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan, South Korea
| | - Seong Kug Eo
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, South Korea
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29
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Tannous S, Ghanem E. A bite to fight: front-line innate immune defenses against malaria parasites. Pathog Glob Health 2018; 112:1-12. [PMID: 29376476 DOI: 10.1080/20477724.2018.1429847] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Malaria infection caused by Plasmodium parasites remains a major health burden worldwide especially in the tropics and subtropics. Plasmodium exhibits a complex life cycle whereby it undergoes a series of developmental stages in the Anopheles mosquito vector and the vertebrate human host. Malaria severity is mainly attributed to the genetic complexity of the parasite which is reflected in the sophisticated mechanisms of invasion and evasion that allow it to overcome the immune responses of both its invertebrate and vertebrate hosts. In this review, we aim to provide an updated, clear and concise summary of the literature focusing on the interactions of the vertebrate innate immune system with Plasmodium parasites, namely sporozoites, merozoites, and trophozoites. The roles of innate immune factors, both humoral and cellular, in anti-Plasmodium defense are described with particular emphasis on the contribution of key innate players including neutrophils, macrophages, and natural killer cells to the clearance of liver and blood stage parasites. A comprehensive understanding of the innate immune responses to malaria parasites remains an important goal that would dramatically help improve the design of original treatment strategies and vaccines, both of which are urgently needed to relieve the burden of malaria especially in endemic countries.
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Affiliation(s)
- Stephanie Tannous
- a Faculty of Natural and Applied Sciences, Department of Sciences , Notre Dame University , Louaize , Lebanon
| | - Esther Ghanem
- a Faculty of Natural and Applied Sciences, Department of Sciences , Notre Dame University , Louaize , Lebanon
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30
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McCarthy CG, Wenceslau CF, Ogbi S, Szasz T, Webb RC. Toll-Like Receptor 9-Dependent AMPK α Activation Occurs via TAK1 and Contributes to RhoA/ROCK Signaling and Actin Polymerization in Vascular Smooth Muscle Cells. J Pharmacol Exp Ther 2018; 365:60-71. [PMID: 29348267 DOI: 10.1124/jpet.117.245746] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/17/2018] [Indexed: 01/06/2023] Open
Abstract
Traditionally, Toll-like receptor 9 (TLR9) signals through an MyD88-dependent cascade that results in proinflammatory gene transcription. Recently, it was reported that TLR9 also participates in a stress tolerance signaling cascade in nonimmune cells. In this noncanonical pathway, TLR9 binds to and inhibits sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 2 (SERCA2), modulating intracellular calcium handling, and subsequently resulting in the activation of 5'-AMP-activated protein kinase α (AMPKα). We have previously reported that TLR9 causes increased contraction in isolated arteries; however, the mechanisms underlying this vascular dysfunction need to be further clarified. Therefore, we hypothesized that noncanonical TLR9 signaling was also present in vascular smooth muscle cells (VSMCs) and that it mediates enhanced contractile responses through SERCA2 inhibition. To test these hypotheses, aortic microsomes, aortic VSMCs, and isolated arteries from male Sprague-Dawley rats were incubated with vehicle or TLR9 agonist (ODN2395). Despite clear AMPKα activation after treatment with ODN2395, SERCA2 activity was unaffected. Alternatively, ODN2395 caused the phosphorylation of AMPKα via transforming growth factor β-activated kinase 1 (TAK1), a kinase involved in TLR9 inflammatory signaling. Downstream, we hypothesized that that TLR9 activation of AMPKα may be important in mediating actin cytoskeleton reorganization. ODN2395 significantly increased the filamentous-to-globular actin ratio, as well as indices of RhoA/Rho-associated protein kinase (ROCK) activation, with the latter being prevented by AMPKα inhibition. In conclusion, AMPKα phosphorylation after TLR9 activation in VSMCs appears to be an extension of traditional inflammatory signaling via TAK1, as opposed to SERCA2 inhibition and the noncanonical pathway. Nonetheless, TLR9-AMPKα signaling can mediate VSMC function via RhoA/ROCK activation and actin polymerization.
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Affiliation(s)
| | | | - Safia Ogbi
- Department of Physiology, Augusta University, Augusta, Georgia
| | - Theodora Szasz
- Department of Physiology, Augusta University, Augusta, Georgia
| | - R Clinton Webb
- Department of Physiology, Augusta University, Augusta, Georgia
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31
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Gheita TA, Sayed S, Azkalany GS, Abaza N, Hammam N, Eissa AH. Toll-like receptor 9 in systemic sclerosis patients: relation to modified Rodnan skin score, disease severity, and functional status. Clin Rheumatol 2017; 37:757-763. [DOI: 10.1007/s10067-017-3880-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/10/2017] [Accepted: 10/15/2017] [Indexed: 01/25/2023]
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32
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Martínez-Campos C, Burguete-García AI, Madrid-Marina V. Role of TLR9 in Oncogenic Virus-Produced Cancer. Viral Immunol 2017; 30:98-105. [DOI: 10.1089/vim.2016.0103] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Cecilia Martínez-Campos
- Dirección de Infecciones Crónicas y Cáncer, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Ana I. Burguete-García
- Dirección de Infecciones Crónicas y Cáncer, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Vicente Madrid-Marina
- Dirección de Infecciones Crónicas y Cáncer, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
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33
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Leifer CA. Dendritic cells in host response to biologic scaffolds. Semin Immunol 2017; 29:41-48. [PMID: 28214177 DOI: 10.1016/j.smim.2017.01.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/23/2017] [Accepted: 01/31/2017] [Indexed: 02/03/2023]
Abstract
Tissue regeneration and repair require a highly complex and orchestrated series of events that require inflammation, but can be compromised when inflammation is excessive or becomes chronic. Macrophages are one of the first cells to contact and respond to implanted materials, and mediate the inflammatory response. The series of events following macrophage association with biomaterials has been well-studied. Dendritic cells (DCs) also directly interact with biomaterials, are critical for specific immune responses, and can be activated in response to interactions with biomaterials. Yet, much less is known about the responses by DCs. This review discusses what we know about DC response to biomaterials, the underlying mechanisms involved, and how DCs can be influenced by the macrophage response to biomaterials. Lastly, I will discuss how biomaterials can be manipulated to enhance or suppress DC function to promote a specific desirable immune response - a major goal for implantable biologically active therapeutics.
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Affiliation(s)
- Cynthia A Leifer
- Department of Microbiology and Immunology College of Veterinary Medicine, C5-153 Cornell University, Ithaca, NY, USA.
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34
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Jin JO, Park H, Zhang W, de Vries JW, Gruszka A, Lee MW, Ahn DR, Herrmann A, Kwak M. Modular delivery of CpG-incorporated lipid-DNA nanoparticles for spleen DC activation. Biomaterials 2016; 115:81-89. [PMID: 27886556 DOI: 10.1016/j.biomaterials.2016.11.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 11/15/2016] [Indexed: 01/31/2023]
Abstract
We introduce a versatile carrier system for in vitro and in vivo immune stimulation based on soft matter DNA nanoparticles (NPs). The incorporation of lipid-modified nucleotides into DNA strands enables the formation of micelles of uniform size. In a single self-assembly step, the micelles can be equipped with immune adjuvant (CpG) motifs and fluorescent probes. The immunological effects of CpG confined at the NP surface were studied in a comprehensive manner in animal experiments. Dose-dependent activation of spleen dendritic cells (DCs) by CpG-conjugated NP was observed, which was accompanied by the pronounced up-regulation of co-stimulatory molecule and cytokine production.
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Affiliation(s)
- Jun-O Jin
- Shanghai Public Health Clinical Center, Shanghai Medical College, Fudan University, Shanghai 201508, China
| | - Haein Park
- Department of Chemistry, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan 48513, Republic of Korea
| | - Wei Zhang
- Shanghai Public Health Clinical Center, Shanghai Medical College, Fudan University, Shanghai 201508, China
| | - Jan Willem de Vries
- University of Groningen, Zernike Institute for Advanced Materials, Department of Polymer Chemistry, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Agnieszka Gruszka
- University of Groningen, Zernike Institute for Advanced Materials, Department of Polymer Chemistry, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Myung Won Lee
- Department of Chemistry, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan 48513, Republic of Korea
| | - Dae-Ro Ahn
- Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology, 5 Hwarangno 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Andreas Herrmann
- University of Groningen, Zernike Institute for Advanced Materials, Department of Polymer Chemistry, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | - Minseok Kwak
- Department of Chemistry, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan 48513, Republic of Korea.
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35
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Alinejad-Rokny H, Anwar F, Waters SA, Davenport MP, Ebrahimi D. Source of CpG Depletion in the HIV-1 Genome. Mol Biol Evol 2016; 33:3205-3212. [PMID: 27682824 DOI: 10.1093/molbev/msw205] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The dinucleotide CpG is highly underrepresented in the genome of human immunodeficiency virus type 1 (HIV-1). To identify the source of CpG depletion in the HIV-1 genome, we investigated two biological mechanisms: (1) CpG methylation-induced transcriptional silencing and (2) CpG recognition by Toll-like receptors (TLRs). We hypothesized that HIV-1 has been under selective evolutionary pressure by these mechanisms leading to the reduction of CpG in its genome. A CpG depleted genome would enable HIV-1 to avoid methylation-induced transcriptional silencing and/or to avoid recognition by TLRs that identify foreign CpG sequences. We investigated these two hypotheses by determining the sequence context dependency of CpG depletion and comparing it with that of CpG methylation and TLR recognition. We found that in both human and HIV-1 genomes the CpG motifs flanked by T/A were depleted most and those flanked by C/G were depleted least. Similarly, our analyses of human methylome data revealed that the CpG motifs flanked by T/A were methylated most and those flanked by C/G were methylated least. Given that a similar CpG depletion pattern was observed for the human genome within which CpGs are not likely to be recognized by TLRs, we argue that the main source of CpG depletion in HIV-1 is likely host-induced methylation. Analyses of CpG motifs in over 100 viruses revealed that this unique CpG representation pattern is specific to the human and simian immunodeficiency viruses.
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Affiliation(s)
- Hamid Alinejad-Rokny
- Infection Analytics, Kirby Institute, UNSW Australia, Sydney, Australia.,Systems Biology and Genomics Lab, Harry Perkins Institute of Medical Research, The University of Western Australia, WA, Australia
| | - Firoz Anwar
- Infection Analytics, Kirby Institute, UNSW Australia, Sydney, Australia
| | - Shafagh A Waters
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, UNSW Australia, Sydney, Australia
| | - Miles P Davenport
- Infection Analytics, Kirby Institute, UNSW Australia, Sydney, Australia
| | - Diako Ebrahimi
- Infection Analytics, Kirby Institute, UNSW Australia, Sydney, Australia .,Department of Biochemistry, Molecular Biology and Biophysics; Masonic Cancer Center; Institute for Molecular Virology, University of Minnesota, MN
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36
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Wu J, Su W, Powner MB, Liu J, Copland DA, Fruttiger M, Madeddu P, Dick AD, Liu L. Pleiotropic action of CpG-ODN on endothelium and macrophages attenuates angiogenesis through distinct pathways. Sci Rep 2016; 6:31873. [PMID: 27558877 PMCID: PMC4997267 DOI: 10.1038/srep31873] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/26/2016] [Indexed: 12/22/2022] Open
Abstract
There is an integral relationship between vascular cells and leukocytes in supporting healthy tissue homeostasis. Furthermore, activation of these two cellular components is key for tissue repair following injury. Toll-like receptors (TLRs) play a role in innate immunity defending the organism against infection, but their contribution to angiogenesis remains unclear. Here we used synthetic TLR9 agonists, cytosine-phosphate-guanosine oligodeoxynucleotides (CpG-ODN), to investigate the role of TLR9 in vascular pathophysiology and identify potential therapeutic translation. We demonstrate that CpG-ODN stimulates inflammation yet inhibits angiogenesis. Regulation of angiogenesis by CpG-ODN is pervasive and tissue non-specific. Further, we noted that synthetic CpG-ODN requires backbone phosphorothioate but not TLR9 activation to render and maintain endothelial stalk cells quiescent. CpG-ODN pre-treated endothelial cells enhance macrophage migration but restrain pericyte mobilisation. CpG-ODN attenuation of angiogenesis, however, remains TLR9-dependent, as inhibition is lost in TLR9 deficient mice. Additionally, CpG-ODNs induce an M1 macrophage phenotype that restricts angiogenesis. The effects mediated by CpG-ODNs can therefore modulate both endothelial cells and macrophages through distinct pathways, providing potential therapeutic application in ocular vascular disease.
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Affiliation(s)
- Jiahui Wu
- Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, UK
| | - Wenru Su
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Sun Yat-sen University, Guangzhou, China
- Centre for Clinic Immunology, Sun Yat-sen University Third Affiliated Hospital, Guangzhou, China
| | - Michael B. Powner
- UCL-Institute of Ophthalmology, University College London, London, UK
| | - Jian Liu
- Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, UK
| | - David A. Copland
- Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, UK
| | - Marcus Fruttiger
- UCL-Institute of Ophthalmology, University College London, London, UK
| | - Paolo Madeddu
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, UK
| | - Andrew D. Dick
- Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, UK
- UCL-Institute of Ophthalmology, University College London, London, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital, London, UK.
| | - Lei Liu
- Academic Unit of Ophthalmology, School of Clinical Sciences, University of Bristol, UK
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37
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Fang F, Marangoni RG, Zhou X, Yang Y, Ye B, Shangguang A, Qin W, Wang W, Bhattacharyya S, Wei J, Tourtellotte WG, Varga J. Toll-like Receptor 9 Signaling Is Augmented in Systemic Sclerosis and Elicits Transforming Growth Factor β-Dependent Fibroblast Activation. Arthritis Rheumatol 2016; 68:1989-2002. [PMID: 26946325 PMCID: PMC9993331 DOI: 10.1002/art.39655] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 02/18/2016] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Although transforming growth factor β (TGFβ) is recognized as being a key trigger of fibroblast activation in systemic sclerosis (SSc), prominent innate immunity suggests that additional pathways contribute to disease persistence. Toll-like receptor 9 (TLR9) is implicated in autoimmunity and fibrosis; however, the expression, mechanism of action, and pathogenic role of TLR9 signaling in SSc remain uncharacterized. The aim of this study was to explore the expression, activity, and potential pathogenic role of TLR9 in the context of skin fibrosis in SSc and in mouse models of experimental fibrosis. METHODS Expression and localization of TLR9 were evaluated in SSc skin biopsy specimens and explanted skin fibroblasts. Fibrotic responses elicited by type A CpG oligonucleotide and mitochondrial DNA (mtDNA) were examined in human skin fibroblasts by a combination of real-time quantitative polymerase chain reaction, Western blot analysis, transient transfection, immunofluorescence microscopy, and functional assays. Expression of TLR9 was examined in 2 distinct mouse models of experimental fibrosis. RESULTS Skin biopsy specimens obtained from 2 independent cohorts of SSc patients showed up-regulation of TLR9, and myofibroblasts were the major cellular source. Moreover, SSc skin biopsy specimens showed evidence of TLR9 pathway activation. CpG induced robust TLR9-dependent fibrotic responses in explanted normal fibroblasts that could be blocked by bortezomib and were mediated through the action of endogenous TGFβ. Mice with experimental fibrosis showed a time-dependent increase in TLR9 localized primarily to myofibroblasts in the dermis. CONCLUSION In isolated fibroblasts, TLR9 elicits fibrotic responses mediated via endogenous TGFβ. In patients with SSc, mtDNA and other damage-associated TLR9 ligands in the skin might trigger localized activation of TLR9 signaling, TGFβ production, and consequent fibroblast activation. Disrupting this fibrotic process with inhibitors targeting TLR9 or its downstream signaling pathways might therefore represent a novel approach to SSc therapy.
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Affiliation(s)
- Feng Fang
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | | | | | - Yang Yang
- China Pharmaceutical University, Nanjing, China
| | - Boping Ye
- China Pharmaceutical University, Nanjing, China
| | - Anna Shangguang
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Wenyi Qin
- University of Illinois at Chicago, Chicago, Illinois
| | - Wenxia Wang
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | | | - Jun Wei
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | | | - John Varga
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Sinha SS, Cameron J, Brooks JC, Leifer CA. Complex Negative Regulation of TLR9 by Multiple Proteolytic Cleavage Events. THE JOURNAL OF IMMUNOLOGY 2016; 197:1343-52. [PMID: 27421483 DOI: 10.4049/jimmunol.1502357] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 06/14/2016] [Indexed: 11/19/2022]
Abstract
TLR9 is an innate immune receptor important for recognizing DNA of host and foreign origin. A mechanism proposed to prevent excessive response to host DNA is the requirement for proteolytic cleavage of TLR9 in endosomes to generate a mature form of the receptor (TLR9(471-1032)). We previously described another cleavage event in the juxtamembrane region of the ectodomain that generated a dominant-negative form of TLR9. Thus, there are at least two independent cleavage events that regulate TLR9. In this study, we investigated whether an N-terminal fragment of TLR9 could be responsible for regulation of the mature or negative-regulatory form. We show that TLR9(471-1032), corresponding to the proteolytically cleaved form, does not function on its own. Furthermore, activity is not rescued by coexpression of the N-terminal fragment (TLR9(1-440)), inclusion of the hinge region (TLR9(441-1032)), or overexpression of UNC93B1, the last of which is critical for trafficking and cleavage of TLR9. TLR9(1-440) coimmunoprecipitates with full-length TLR9 and TLR9(471-1032) but does not rescue the native glycosylation pattern; thus, inappropriate trafficking likely explains why TLR9(471-1032) is nonfunctional. Lastly, we show that TLR9(471-1032) is also a dominant-negative regulator of TLR9 signaling. Together, these data provide a new perspective on the complexity of TLR9 regulation by proteolytic cleavage and offer potential ways to inhibit activity through this receptor, which may dampen autoimmune inflammation.
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Affiliation(s)
- Siddhartha S Sinha
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and
| | - Jody Cameron
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and
| | - James C Brooks
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and Glycobia Inc., Ithaca, NY 14853
| | - Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and
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Leifer CA, Medvedev AE. Molecular mechanisms of regulation of Toll-like receptor signaling. J Leukoc Biol 2016; 100:927-941. [PMID: 27343013 DOI: 10.1189/jlb.2mr0316-117rr] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/01/2016] [Indexed: 01/22/2023] Open
Abstract
TLRs play a critical role in the detection of microbes and endogenous "alarmins" to initiate host defense, yet they can also contribute to the development and progression of inflammatory and autoimmune diseases. To avoid pathogenic inflammation, TLR signaling is subject to multilayer regulatory control mechanisms, including cooperation with coreceptors, post-translational modifications, cleavage, cellular trafficking, and interactions with negative regulators. Nucleic acid-sensing TLRs are particularly interesting in this regard, as they can both recognize host-derived structures and require internalization of their ligand as a result of intracellular sequestration of the nucleic acid-sensing TLRs. This review summarizes the regulatory mechanisms of TLRs, including regulation of their access to ligands, receptor folding, intracellular trafficking, and post-translational modifications, as well as how altered control mechanism could contribute to inflammatory and autoimmune disorders.
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Affiliation(s)
- Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA; and
| | - Andrei E Medvedev
- Department of Immunology, University of Connecticut Heath Center, Farmington, Connecticut, USA
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40
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Foronjy RF, Salathe MA, Dabo AJ, Baumlin N, Cummins N, Eden E, Geraghty P. TLR9 expression is required for the development of cigarette smoke-induced emphysema in mice. Am J Physiol Lung Cell Mol Physiol 2016; 311:L154-66. [PMID: 27288485 PMCID: PMC4967186 DOI: 10.1152/ajplung.00073.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/04/2016] [Indexed: 11/22/2022] Open
Abstract
The expression of Toll-like receptor (TLR)-9, a pathogen recognition receptor that recognizes unmethylated CpG sequences in microbial DNA molecules, is linked to the pathogenesis of several lung diseases. TLR9 expression and signaling was investigated in animal and cell models of chronic obstructive pulmonary disease (COPD). We observed enhanced TLR9 expression in mouse lungs following exposure to cigarette smoke. Tlr9(-/-) mice were resistant to cigarette smoke-induced loss of lung function as determined by mean linear intercept, total lung capacity, lung compliance, and tissue elastance analysis. Tlr9 expression also regulated smoke-mediated immune cell recruitment to the lung; apoptosis; expression of granulocyte-colony stimulating factor (G-CSF), the CXCL5 protein, and matrix metalloproteinase-2 (MMP-2); and protein tyrosine phosphatase 1B (PTP1B) activity in the lung. PTP1B, a phosphatase with anti-inflammatory abilities, was identified as binding to TLR9. In vivo delivery of a TLR9 agonist enhanced TLR9 binding to PTP1B, which inactivated PTP1B. Ptp1b(-/-) mice had elevated lung concentrations of G-CSF, CXCL5, and MMP-2, and tissue expression of type-1 interferon following TLR9 agonist administration, compared with wild-type mice. TLR9 responses were further determined in fully differentiated normal human bronchial epithelial (NHBE) cells isolated from nonsmoker, smoker, and COPD donors, and then cultured at air liquid interface. NHBE cells from smokers and patients with COPD expressed more TLR9 and secreted greater levels of G-CSF, IL-6, CXCL5, IL-1β, and MMP-2 upon TLR9 ligand stimulation compared with cells from nonsmoker donors. Although TLR9 combats infection, our results indicate that TLR9 induction can affect lung function by inactivating PTP1B and upregulating expression of proinflammatory cytokines.
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Affiliation(s)
- Robert F Foronjy
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, New York; Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York
| | - Matthias A Salathe
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Miami, Miami, Florida; and
| | - Abdoulaye J Dabo
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, New York; Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York
| | - Nathalie Baumlin
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, University of Miami, Miami, Florida; and
| | - Neville Cummins
- Division of Pulmonary and Critical Care Medicine, Mount Sinai Roosevelt, Mount Sinai Health System, New York, New York
| | - Edward Eden
- Division of Pulmonary and Critical Care Medicine, Mount Sinai Roosevelt, Mount Sinai Health System, New York, New York
| | - Patrick Geraghty
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, New York; Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York;
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41
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Zhu G, Liu Y, Yang X, Kim YH, Zhang H, Jia R, Liao HS, Jin A, Lin J, Aronova M, Leapman R, Nie Z, Niu G, Chen X. DNA-inorganic hybrid nanovaccine for cancer immunotherapy. NANOSCALE 2016; 8:6684-92. [PMID: 26947116 PMCID: PMC4807396 DOI: 10.1039/c5nr08821f] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Cancer evolves to evade or compromise the surveillance of the immune system, and cancer immunotherapy aims to harness the immune system in order to inhibit cancer development. Unmethylated CpG dinucleotide-containing oligonucleotides (CpG), a class of potent adjuvants that activate the toll-like receptor 9 (TLR9) located in the endolysosome of many antigen-presenting cells (APCs), are promising for cancer immunotherapy. However, clinical application of synthetic CpG confronts many challenges such as suboptimal delivery into APCs, unfavorable pharmacokinetics caused by limited biostability and short in vivo half-life, and side effects associated with leaking of CpG into the systemic circulation. Here we present DNA-inorganic hybrid nanovaccines (hNVs) for efficient uptake into APCs, prolonged tumor retention, and potent immunostimulation and cancer immunotherapy. hNVs were self-assembled from concatemer CpG analogs and magnesium pyrophosphate (Mg2PPi). Mg2PPi renders hNVs resistant to nuclease degradation and thermal denaturation, both of which are demanding characteristics for effective vaccination and the storage and transportation of vaccines. Fluorophore-labeled hNVs were tracked to be efficiently internalized into the endolysosomes of APCs, where Mg2PPi was dissolved in an acidic environment and thus CpG analogs were exposed to hNVs. Internalized hNVs in APCs led to (1) elevated secretion of proinflammatory factors, and (2) elevated expression of co-stimulatory factors. Compared with molecular CpG, hNVs dramatically prolonged the tissue retention of CpG analogs and reduced splenomegaly, a common side effect of CpG. In a melanoma mouse model, two injections of hNVs significantly inhibited the tumor growth and outperformed the molecular CpG. These results suggest hNVs are promising for cancer immunotherapy.
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Affiliation(s)
- Guizhi Zhu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
| | - Yijing Liu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
| | - Xiangyu Yang
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
| | - Young-Hwa Kim
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
| | - Huimin Zhang
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
| | - Rui Jia
- Section on Intracellular Protein Trafficking, Cell Biology and Metabolism Program, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Hsien-Shun Liao
- Laboratory of Cellular Imaging and Macromolecular Biophysics, NIBIB, NIH, Bethesda, MD 20892, USA
| | - Albert Jin
- Laboratory of Cellular Imaging and Macromolecular Biophysics, NIBIB, NIH, Bethesda, MD 20892, USA
| | - Jing Lin
- Laboratory of Cellular Imaging and Macromolecular Biophysics, NIBIB, NIH, Bethesda, MD 20892, USA
| | - Maria Aronova
- Laboratory of Cellular Imaging and Macromolecular Biophysics, NIBIB, NIH, Bethesda, MD 20892, USA
| | - Richard Leapman
- Laboratory of Cellular Imaging and Macromolecular Biophysics, NIBIB, NIH, Bethesda, MD 20892, USA
| | - Zhihong Nie
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Gang Niu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
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42
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Hasan M, Gruber E, Cameron J, Leifer CA. TLR9 stability and signaling are regulated by phosphorylation and cell stress. J Leukoc Biol 2016; 100:525-33. [PMID: 26957214 DOI: 10.1189/jlb.2a0815-337r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/02/2016] [Indexed: 12/27/2022] Open
Abstract
Innate sensing of pathogens elicits protective immune responses through pattern recognition receptors, including Toll-like receptors. Although signaling by Toll-like receptors is regulated at multiple steps, including localization, trafficking, proteolytic cleavage, and phosphorylation, the significance of post-translational modifications and cellular stress response on Toll-like receptor stability and signaling is still largely unknown. In the present study, we investigated the role of cytoplasmic tyrosine motifs in Toll-like receptor-9 stability, proteolytic cleavage, and signaling. We demonstrated that tyrosine phosphorylation is essential for mouse Toll-like receptor-9 protein stability and signaling. Upon inhibition of tyrosine kinases with piceatannol, Toll-like receptor-9 tyrosine phosphorylation induced by CpG deoxyribonucleic acid was inhibited, which correlated with decreased signaling. Furthermore, inhibition of Src kinases with 1-tert-Butyl-3-(4-chlorophenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine also inhibited response to CpG deoxyribonucleic acid. Toll-like receptor-9 protein stability was also sensitive to autophagy, the cellular stress response pathway, and infection by a deoxyribonucleic acid virus. Whereas autophagy induced by rapamycin or low serum levels caused a preferential loss of the mature p80 proteolytic cleavage product, infection with herpes simplex virus-1 and induction of cell stress with tunicamycin caused preferential loss of full-length Toll-like receptor-9, which is localized to the endoplasmic reticulum. Our data reveal new information about the stability and signaling of Toll-like receptor-9 and suggest that immune evasion mechanisms may involve targeted loss of innate sensing receptors.
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Affiliation(s)
- Maroof Hasan
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Erika Gruber
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Jody Cameron
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
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43
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The proprotein convertase PC1/3 regulates TLR9 trafficking and the associated signaling pathways. Sci Rep 2016; 6:19360. [PMID: 26778167 PMCID: PMC4725977 DOI: 10.1038/srep19360] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/23/2015] [Indexed: 12/19/2022] Open
Abstract
Endosomal TLR9 is considered as a potent anti-tumoral therapeutic target. Therefore, it is crucial to decipher the mechanisms controlling its trafficking since it determines TLR9 activation and signalling. At present, the scarcity of molecular information regarding the control of this trafficking and signalling is noticeable. We have recently demonstrated that in macrophages, proprotein convertase 1/3 (PC1/3) is a key regulator of TLR4 Myd88-dependent signalling. In the present study, we established that PC1/3 also regulates the endosomal TLR9. Under CpG-ODN challenge, we found that PC1/3 traffics rapidly to co-localize with TLR9 in CpG-ODN-containing endosomes with acidic pH. In PC1/3 knockdown macrophages, compartmentalization of TLR9 was altered and TLR9 clustered in multivesicular bodies (MVB) as demonstrated by co-localization with Rab7. This demonstrates that PC1/3 controls TLR9 trafficking. This clustering of TLR9 in MVB dampened the anti-inflammatory STAT3 signalling pathway while it promoted the pro-inflammatory NF-kB pathway. As a result, macrophages from PC1/3 KO mice and rat PC1/3-KD NR8383 macrophages secreted more pro-inflammatory cytokines such as TNF-α, IL6, IL1α and CXCL2. This is indicative of a M1 pro-inflammatory phenotype. Therefore, PC1/3 KD macrophages represent a relevant mean for cell therapy as “Trojan” macrophages.
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44
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Chaparro-Garcia A, Schwizer S, Sklenar J, Yoshida K, Petre B, Bos JIB, Schornack S, Jones AME, Bozkurt TO, Kamoun S. Phytophthora infestans RXLR-WY Effector AVR3a Associates with Dynamin-Related Protein 2 Required for Endocytosis of the Plant Pattern Recognition Receptor FLS2. PLoS One 2015; 10:e0137071. [PMID: 26348328 PMCID: PMC4562647 DOI: 10.1371/journal.pone.0137071] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 08/12/2015] [Indexed: 11/18/2022] Open
Abstract
Pathogens utilize effectors to suppress basal plant defense known as PTI (Pathogen-associated molecular pattern-triggered immunity). However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that the co-receptor BAK1/SERK3 contributes to basal immunity against the potato pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated cell death by binding the plant E3 ligase CMPG1. In contrast, AVR3aKI-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and does not suppress INF1-mediated cell death. Here, we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3-dependent PTI responses in N. benthamiana using the elicitor/receptor pair flg22/FLS2 as a model. We found that all tested variants of AVR3a suppress defense responses triggered by flg22 and reduce internalization of activated FLS2. Moreover, we discovered that AVR3a associates with the Dynamin-Related Protein 2 (DRP2), a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, silencing of DRP2 impaired ligand-induced FLS2 internalization but did not affect internalization of the growth receptor BRI1. Our results suggest that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis. We conclude that AVR3a is a multifunctional effector that can suppress BAK1/SERK3-mediated immunity through at least two different pathways.
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Affiliation(s)
| | - Simon Schwizer
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Jan Sklenar
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Kentaro Yoshida
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Benjamin Petre
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Jorunn I. B. Bos
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | | | | | - Tolga O. Bozkurt
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Sophien Kamoun
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
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45
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Wu JY, Kuo CC. ADP-Ribosylation Factor 3 Mediates Cytidine-Phosphate-Guanosine Oligodeoxynucleotide-Induced Responses by Regulating Toll-Like Receptor 9 Trafficking. J Innate Immun 2015; 7:623-36. [PMID: 26067373 DOI: 10.1159/000430785] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 04/17/2015] [Indexed: 11/19/2022] Open
Abstract
Toll-like receptor 9 (TLR9) trafficking from the endoplasmic reticulum (ER) into endolysosomes is critical for eliciting cytidine-phosphate-guanosine (CpG) DNA-mediated immune responses. ADP-ribosylation factor 3 (ARF3) is a member of the Ras superfamily, which is crucial for a wide variety of cellular events including protein trafficking. In this study, we found that the inhibition of ARF3 by dominant mutants and siRNA impaired CpG oligodeoxynucleotide (ODN)-mediated responses whereas cells expressing the constitutively active ARF3 mutant enhanced CpG ODN-induced NF-x03BA;B activation and cytokine production. Further experiments with MyD88-overexpressing fibroblast cells transfected with a dominant-negative mutant and a constitutively active mutant of ARF3 demonstrated that ARF3 regulated CpG ODN-mediated signaling upstream of MyD88. Additional studies have shown that ARF3 inhibition impairs TLR9 trafficking from the ER into endolysosomes, thereby inhibiting the functional cleavage of TLR9, although it has no significant effect on CpG ODN uptake. Furthermore, activated ARF3 is associated with Unc93B1 and TLR9, suggesting that ARF3 conducts TLR9 trafficking by forming the TLR9-Unc93B1-ARF3 complex. Overall, our findings demonstrate that a novel ARF3 axis pathway mediates CpG ODN-induced responses by regulating TLR9 trafficking.
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Affiliation(s)
- Jing-Yiing Wu
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Taiwan, ROC
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46
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Sartorius R, D'Apice L, Trovato M, Cuccaro F, Costa V, De Leo MG, Marzullo VM, Biondo C, D'Auria S, De Matteis MA, Ciccodicola A, De Berardinis P. Antigen delivery by filamentous bacteriophage fd displaying an anti-DEC-205 single-chain variable fragment confers adjuvanticity by triggering a TLR9-mediated immune response. EMBO Mol Med 2015; 7:973-88. [PMID: 25888235 PMCID: PMC4520660 DOI: 10.15252/emmm.201404525] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Filamentous bacteriophage fd particles delivering antigenic determinants via DEC-205 (fdsc-αDEC) represent a powerful delivery system that induces CD8+ T-cell responses even when administered in the absence of adjuvants or maturation stimuli for dendritic cells. In order to investigate the mechanisms of this activity, RNA-Sequencing of fd-pulsed dendritic cells was performed. A significant differential expression of genes involved in innate immunity, co-stimulation and cytokine production was observed. In agreement with these findings, we demonstrate that induction of proinflammatory cytokines and type I interferon by fdsc-αDEC was MYD88 mediated and TLR9 dependent. We also found that fdsc-αDEC is delivered into LAMP-1-positive compartments and co-localizes with TLR9. Thus, phage particles containing a single-strand DNA genome rich in CpG motifs delivered via DEC-205 are able to intercept and trigger the active TLR9 innate immune receptor into late endosome/lysosomes and to enhance the immunogenicity of the displayed antigenic determinants. These findings make fd bacteriophage a valuable tool for immunization without administering exogenous adjuvants.
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Affiliation(s)
- Rossella Sartorius
- Institute of Protein Biochemistry, National Council of Research, Naples, Italy
| | - Luciana D'Apice
- Institute of Protein Biochemistry, National Council of Research, Naples, Italy
| | - Maria Trovato
- Institute of Protein Biochemistry, National Council of Research, Naples, Italy
| | - Fausta Cuccaro
- Institute of Protein Biochemistry, National Council of Research, Naples, Italy
| | - Valerio Costa
- Institute of Genetics and Biophysics A. Buzzati-Traverso, National Council of Research, Naples, Italy
| | | | - Vincenzo Manuel Marzullo
- Institute of Protein Biochemistry, National Council of Research, Naples, Italy Telethon Institute of Genetics and Medicine, Pozzuoli (NA), Italy
| | - Carmelo Biondo
- Department of Pediatric, Gynecological, Microbiological and Biomedical Sciences, University of Messina, Messina, Italy
| | - Sabato D'Auria
- Institute of Protein Biochemistry, National Council of Research, Naples, Italy Institute of Food Science, National Council of Research, Avellino, Italy
| | | | - Alfredo Ciccodicola
- Institute of Genetics and Biophysics A. Buzzati-Traverso, National Council of Research, Naples, Italy Department of Science and Technology, University Parthenope of Naples, Naples, Italy
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47
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Bryant CE, Gay NJ, Heymans S, Sacre S, Schaefer L, Midwood KS. Advances in Toll-like receptor biology: Modes of activation by diverse stimuli. Crit Rev Biochem Mol Biol 2015; 50:359-79. [DOI: 10.3109/10409238.2015.1033511] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | - Nick J. Gay
- Department of Biochemistry, University of Cambridge, Cambridge, UK,
| | - Stephane Heymans
- Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium,
- ICIN – Netherlands Heart Institute, Utrecht, The Netherlands,
| | - Sandra Sacre
- Brighton & Sussex Medical School, University of Sussex, Brighton, UK,
| | - Liliana Schaefer
- Pharmazentrum Frankfurt/ZAFES, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität Frankfurt am Main, Frankfurt am Main, Germany, and
| | - Kim S. Midwood
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
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48
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Bozkurt TO, Belhaj K, Dagdas YF, Chaparro-Garcia A, Wu CH, Cano LM, Kamoun S. Rerouting of plant late endocytic trafficking toward a pathogen interface. Traffic 2015; 16:204-26. [PMID: 25430691 DOI: 10.1111/tra.12245] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 12/13/2022]
Abstract
A number of plant pathogenic and symbiotic microbes produce specialized cellular structures that invade host cells where they remain enveloped by host-derived membranes. The mechanisms underlying the biogenesis and functions of host-microbe interfaces are poorly understood. Here, we show that plant late endocytic trafficking is diverted toward the extrahaustorial membrane (EHM); a host-pathogen interface that develops in plant cells invaded by Irish potato famine pathogen Phytophthora infestans. A late endosome and tonoplast marker protein Rab7 GTPase RabG3c, but not a tonoplast-localized sucrose transporter, is recruited to the EHM, suggesting specific rerouting of vacuole-targeted late endosomes to a host-pathogen interface. We revealed the dynamic nature of this process by showing that, upon activation, a cell surface immune receptor traffics toward the haustorial interface. Our work provides insight into the biogenesis of the EHM and reveals dynamic processes that recruit membrane compartments and immune receptors to this host-pathogen interface.
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Affiliation(s)
- Tolga O Bozkurt
- The Sainsbury Laboratory, Norwich Research Park, Norwich, UK; Current address: Department of Life Sciences, Imperial College London, London, UK
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Mechanistic insight into the TH1-biased immune response to recombinant subunit vaccines delivered by probiotic bacteria-derived outer membrane vesicles. PLoS One 2014; 9:e112802. [PMID: 25426709 PMCID: PMC4245113 DOI: 10.1371/journal.pone.0112802] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 10/15/2014] [Indexed: 02/08/2023] Open
Abstract
Recombinant subunit vaccine engineering increasingly focuses on the development of more effective delivery platforms. However, current recombinant vaccines fail to sufficiently stimulate protective adaptive immunity against a wide range of pathogens while remaining a cost effective solution to global health challenges. Taking an unorthodox approach to this fundamental immunological challenge, we isolated the TLR-targeting capability of the probiotic E. coli Nissle 1917 bacteria (EcN) by engineering bionanoparticlate antigen carriers derived from EcN outer membrane vesicles (OMVs). Exogenous model antigens expressed by these modified bacteria as protein fusions with the bacterial enterotoxin ClyA resulted in their display on the surface of the carrier OMVs. Vaccination with the engineered EcN OMVs in a BALB/c mouse model, and subsequent mechanism of action analysis, established the EcN OMV’s ability to induce self-adjuvanted robust and protective humoral and TH1-biased cellular immunity to model antigens. This finding appears to be strain-dependent, as OMV antigen carriers similarly engineered from a standard K12 E. coli strain derivative failed to generate a comparably robust antigen-specific TH1 bias. The results demonstrate that unlike traditional subunit vaccines, these biomolecularly engineered “pathogen-like particles” derived from traditionally overlooked, naturally potent immunomodulators have the potential to effectively couple recombinant antigens with meaningful immunity in a broadly applicable fashion.
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Leifer CA, McConkey C, Li S, Chassaing B, Gewirtz AT, Ley RE. Linking genetic variation in human Toll-like receptor 5 genes to the gut microbiome's potential to cause inflammation. Immunol Lett 2014; 162:3-9. [PMID: 25284610 DOI: 10.1016/j.imlet.2014.07.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 07/14/2014] [Accepted: 07/28/2014] [Indexed: 01/19/2023]
Abstract
Immunodeficiencies can lead to alterations of the gut microbiome that render it pathogenic and capable of transmitting disease to naïve hosts. Here, we review the role of Toll-like receptor (TLR) 5, the innate receptor for bacterial flagellin, in immune responses to the normal gut microbiota with a focus its role on adaptive immunity. Loss of TLR5 has profound effects on the microbiota that include greater temporal instability of major lineages and upregulation of flagellar motility genes that may be linked to the reduced levels of anti-flagellin antibodies in the TLR5(-/-) host. A variety of human TLR5 gene alleles exist that also associated with inflammatory conditions and may do so via effects on the gut microbiome and altered host-microbial crosstalk.
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Affiliation(s)
- Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, United States.
| | - Cameron McConkey
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, United States
| | - Sha Li
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, United States
| | - Benoit Chassaing
- Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA 30303, United States
| | - Andrew T Gewirtz
- Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA 30303, United States
| | - Ruth E Ley
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, United States.
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