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Espada CE, Sari L, Cahill MP, Yang H, Phillips S, Martinez N, Kenney AD, Yount JS, Xiong Y, Lin MM, Wu L. SAMHD1 impairs type I interferon induction through the MAVS, IKKε, and IRF7 signaling axis during viral infection. J Biol Chem 2023; 299:104925. [PMID: 37328105 PMCID: PMC10404699 DOI: 10.1016/j.jbc.2023.104925] [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: 05/02/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/18/2023] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) restricts human immunodeficiency virus type 1 (HIV-1) infection by reducing the intracellular dNTP pool. We have shown that SAMHD1 suppresses nuclear factor kappa-B activation and type I interferon (IFN-I) induction by viral infection and inflammatory stimuli. However, the mechanism by which SAMHD1 inhibits IFN-I remains unclear. Here, we show that SAMHD1 inhibits IFN-I activation induced by the mitochondrial antiviral-signaling protein (MAVS). SAMHD1 interacted with MAVS and suppressed MAVS aggregation in response to Sendai virus infection in human monocytic THP-1 cells. This resulted in increased phosphorylation of TANK binding kinase 1 (TBK1), inhibitor of nuclear factor kappa-B kinase epsilon (IKKε), and IFN regulatory factor 3 (IRF3). SAMHD1 suppressed IFN-I activation induced by IKKε and prevented IRF7 binding to the kinase domain of IKKε. We found that SAMHD1 interaction with the inhibitory domain (ID) of IRF7 (IRF7-ID) was necessary and sufficient for SAMHD1 suppression of IRF7-mediated IFN-I activation in HEK293T cells. Computational docking and molecular dynamics simulations revealed possible binding sites between IRF7-ID and full-length SAMHD1. Individual substitution of F411, E416, or V460 in IRF7-ID significantly reduced IRF7 transactivation activity and SAMHD1 binding. Furthermore, we investigated the role of SAMHD1 inhibition of IRF7-mediated IFN-I induction during HIV-1 infection. We found that THP-1 cells lacking IRF7 expression had reduced HIV-1 infection and viral transcription compared to control cells, indicating a positive role of IRF7 in HIV-1 infection. Our findings suggest that SAMHD1 suppresses IFN-I induction through the MAVS, IKKε, and IRF7 signaling axis.
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Affiliation(s)
- Constanza E Espada
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Levent Sari
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Michael P Cahill
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Hua Yang
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Stacia Phillips
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Nicholas Martinez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Adam D Kenney
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | - Jacob S Yount
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Milo M Lin
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
| | - Li Wu
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
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Mori L, Valente ST. Cure and Long-Term Remission Strategies. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2407:391-428. [PMID: 34985678 DOI: 10.1007/978-1-0716-1871-4_26] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The majority of virally suppressed individuals will experience rapid viral rebound upon antiretroviral therapy (ART) interruption, providing a strong rationale for the development of cure strategies. Moreover, despite ART virological control, HIV infection is still associated with chronic immune activation, inflammation, comorbidities, and accelerated aging. These effects are believed to be due, in part, to low-grade persistent transcription and trickling production of viral proteins from the pool of latent proviruses constituting the viral reservoir. In recent years there has been an increasing interest in developing what has been termed a functional cure for HIV. This approach entails the long-term, durable control of viral expression in the absence of therapy, preventing disease progression and transmission, despite the presence of detectable integrated proviruses. One such strategy, the block-and-lock approach for a functional cure, proposes the epigenetic silencing of proviral expression, locking the virus in a profound latent state, from which reactivation is very unlikely. The proof-of-concept for this approach was demonstrated with the use of a specific small molecule targeting HIV transcription. Here we review the principles behind the block-and-lock approach and some of the additional strategies proposed to silence HIV expression.
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Affiliation(s)
- Luisa Mori
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Susana T Valente
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA.
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Lu GF, Chen SC, Xia YP, Ye ZM, Cao F, Hu B. Synergistic inflammatory signaling by cGAS may be involved in the development of atherosclerosis. Aging (Albany NY) 2021; 13:5650-5673. [PMID: 33589571 PMCID: PMC7950297 DOI: 10.18632/aging.202491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/23/2020] [Indexed: 12/29/2022]
Abstract
Inappropriate activation or overactivation of cyclic GMP-AMP synthase (cGAS) by double-stranded deoxyribonucleic acid (dsDNA) initiates a regulatory signaling cascade triggering a variety of inflammatory responses, which are a great threat to human health. This study focused on identifying the role of cGAS in atherosclerosis and its potential mechanisms. The relationship between cGAS and atherosclerosis was identified in an ApoE -/- mouse model. Meanwhile, RNA sequencing (RNA-seq) analysis of the underlying mechanisms of atherosclerosis in RAW264.7 macrophages treated with cGAS inhibition was conducted. Results showed that cGAS was positively correlated with atherosclerotic plaque area, and was mainly distributed in macrophages. RNA-seq analysis revealed that inflammatory response, immune response and cytokine–cytokine receptor interaction may play important roles in the development of atherosclerosis. Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that the expression of the pro-inflammatory factors, signal transducer and activator of transcription (Stat), interferon regulatory factor (Irf), toll-like receptors (Tlrs), and type I interferons (Ifns) were synergistically reduced when cGAS was inhibited. Furthermore, cGAS inhibition significantly inhibited RAW264.7 macrophage M1 polarization. These results demonstrate that cGAS may contribute to the development of atherosclerosis through synergistic inflammatory signaling of TLRs, STAT/IRF as well as IFNs, leading to macrophage M1 polarization.
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Affiliation(s)
- Guan-Feng Lu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Sheng-Cai Chen
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yuan-Peng Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zi-Ming Ye
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,Department of Neurology, The First Affiliated Hospital, Guangxi Medical University, Nanning 530021, Guangxi, China
| | - Fei Cao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Bo Hu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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Lenart M, Działo E, Kluczewska A, Węglarczyk K, Szaflarska A, Rutkowska-Zapała M, Surmiak M, Sanak M, Pituch-Noworolska A, Siedlar M. miRNA Regulation of NK Cells Antiviral Response in Children With Severe and/or Recurrent Herpes Simplex Virus Infections. Front Immunol 2021; 11:589866. [PMID: 33679688 PMCID: PMC7931645 DOI: 10.3389/fimmu.2020.589866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/07/2020] [Indexed: 12/21/2022] Open
Abstract
Severe and/or recurrent infection with Herpes simplex virus (HSV) is observed in a large group of patients treated in clinical immunology facilities. Atypical and prolonged HSV infection is the most common clinical manifestation of disturbed NK cell development and functions, yet the molecular basis of these disorders is still largely unknown. Since recent findings indicated the importance of miRNA in regulating NK cell development, maturation and functions, the aim of our study was to investigate miRNA expression pattern in NK cells in patients with severe and/or recurrent infections with HSV and analyze the role of these miRNAs in NK cell antiviral response. As a result, miRNA expression pattern analysis of human best known 754 miRNAs revealed that patients with severe and/or recurrent HSV infection had substantially upregulated expression of four miRNAs: miR-27b, miR-199b, miR-369-3p and miR-491-3p, when compared to healthy controls. Selective inhibition of miR-27b, miR-199b, miR-369-3p and miR-491-3p expression in NK-92 cells resulted in profound upregulation of 4 genes (APOBEC3G, MAP2K3, MAVS and TLR7) and downregulation of 36 genes taking part in antiviral response or associated with signaling pathways of Toll-like receptors (TLR), NOD-like receptors, the retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) and type I IFN-related response. Additionally, flow cytometry analysis revealed that miR-369-3p and miR-491-3p inhibitors downregulated NK cell intracellular perforin expression, while the expression of granzyme B and IFNγ remained unchanged. Taken together, our study suggests a novel mechanism which may promote recurrence and severity of HSV infection, based on miRNAs-dependent posttranscriptional regulation of genes taking part in antiviral response of human NK cells.
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Affiliation(s)
- Marzena Lenart
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
| | - Edyta Działo
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
| | - Anna Kluczewska
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
| | - Kazimierz Węglarczyk
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
| | - Anna Szaflarska
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
| | - Magdalena Rutkowska-Zapała
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
| | - Marcin Surmiak
- II Department of Internal Medicine, Jagiellonian University Medical College, Krakow, Poland
| | - Marek Sanak
- II Department of Internal Medicine, Jagiellonian University Medical College, Krakow, Poland
| | - Anna Pituch-Noworolska
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
| | - Maciej Siedlar
- Department of Clinical Immunology, Institute of Pediatrics, Jagiellonian University Medical College, Krakow, Poland
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TLR4 abrogates the Th1 immune response through IRF1 and IFN-β to prevent immunopathology during L. infantum infection. PLoS Pathog 2020; 16:e1008435. [PMID: 32210480 PMCID: PMC7135367 DOI: 10.1371/journal.ppat.1008435] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 04/06/2020] [Accepted: 02/25/2020] [Indexed: 12/26/2022] Open
Abstract
A striking feature of human visceral leishmaniasis (VL) is chronic inflammation in the spleen and liver, and VL patients present increased production levels of multiple inflammatory mediators, which contribute to tissue damage and disease severity. Here, we combined an experimental model with the transcriptional profile of human VL to demonstrate that the TLR4-IFN-β pathway regulates the chronic inflammatory process and is associated with the asymptomatic form of the disease. Tlr4-deficient mice harbored fewer parasites in their spleen and liver than wild-type mice. TLR4 deficiency enhanced the Th1 immune response against the parasite, which was correlated with an increased activation of dendritic cells (DCs). Gene expression analyses demonstrated that IRF1 and IFN-β were expressed downstream of TLR4 after infection. Accordingly, IRF1- and IFNAR-deficient mice harbored fewer parasites in the target organs than wild-type mice due to having an increased Th1 immune response. However, the absence of TLR4 or IFNAR increased the serum transaminase levels in infected mice, indicating the presence of liver damage in these animals. In addition, IFN-β limits IFN-γ production by acting directly on Th1 cells. Using RNA sequencing analysis of human samples, we demonstrated that the transcriptional signature for the TLR4 and type I IFN (IFN-I) pathways was positively modulated in asymptomatic subjects compared with VL patients and thus provide direct evidence demonstrating that the TLR4-IFN-I pathway is related to the nondevelopment of the disease. In conclusion, our results demonstrate that the TLR4-IRF1 pathway culminates in IFN-β production as a mechanism for dampening the chronic inflammatory process and preventing immunopathology development. Visceral leishmaniasis (VL) is one of the most lethal neglected tropical diseases and is caused by Leishmania parasites. Most subjects infected with Leishmania present subclinical VL symptoms, and their immune response is mediated by Th1 cells and immunoregulatory mechanisms. However, when infection progresses to disease, VL patients present increased levels of inflammatory mediators in the serum which are related to the severity of disease. During infection, Toll-like receptors (TLRs) interact with Leishmania parasites and contribute to the outcome of the disease. Herein, we report that TLR4 signaling hampers the chronic immune response during VL to prevent immunopathology. TLR4 triggers the activation of IRF1 and thus induces the transcription of IFN-β, which in turn acts directly on Th1 cells to limit the production of IFN-γ. In addition, a transcription analysis of human VL samples provides direct evidence demonstrating that the TLR4-IFN-I pathway is related to the asymptomatic form of the disease. Collectively, our findings reveal that TLR4 hampers the Th1 immune response through IRF1 and IFN-β to prevent immunopathology during VL.
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Establishment of a Temperature-Sensitive Model of Oncogene-Induced Senescence in Angiosarcoma Cells. Cancers (Basel) 2020; 12:cancers12020395. [PMID: 32046305 PMCID: PMC7072444 DOI: 10.3390/cancers12020395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 11/17/2022] Open
Abstract
Lesions with driver mutations, including atypical nevi and seborrheic keratoses, are very common in dermatology, and are prone to senescence. The molecular events that prevent senescent lesions from becoming malignant are not well understood. We have developed a model of vascular proliferation using a temperature-sensitive, large T antigen and oncogenic HRas. By elevating the temperature to 39 °C, we can turn off large T antigen and study the molecular events in cells with the Ras driver mutation. To assess the signaling events associated with the switch from a proliferative to a nonproliferative state in the constant presence of a driver oncogene, SVR cells were cultivated for 24 and 48 h and compared with SVR cells at 37 °C. Cells were evaluated by Western Blot (WB) gene chip microarray (GC) and quantitative reverse transcription polymerase chain reaction (RT-qPCR). Upon evaluation, a novel phenotype was observed in endothelial cells after switching off the large T antigen. This phenotype was characterized by Notch activation, downregulation of p38 phosphorylation, downregulation of the master immune switch IRF7, and downregulation of hnRNP A0. Switching off proliferative signaling may result in immune privilege and Notch activation, which may account, in part, for the survival of common skin lesions.
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7
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IL-7-induced proliferation of peripheral Th17 cells is impaired in HAART-controlled HIV infection. AIDS 2019; 33:985-991. [PMID: 30946152 DOI: 10.1097/qad.0000000000002164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Th17 cells are key regulators of functional immunity in mucosal tissues, including the gut-associated lymphoid tissue (GALT), an important site of immune impairment in HIV infection. During HIV infection, Th17 cells are lost in large numbers from the GALT. Despite the recovery of peripheral CD4 T cells that accompanies suppression of viral replication with HAART, Th17 cells in GALT are not completely restored. IL-7 is essential for the survival and proliferation of T cells, but its signaling through its receptor IL-7Rα (CD127), is impaired in CD8 T cells and thymocytes during HIV infection. We set out to determine if decreased CD127 expression or impaired CD127 signaling may be the cause of Th17 impairment in HAART-controlled HIV infection. DESIGN Healthy and HIV donors on HAART were selected for this study of Th17 cell function in HIV. METHODS Peripheral CD4 T cells and Th17 cells were isolated using magnetic beads, then stimulated with IL-7. CD127 expression and the phosphorylation of signaling molecules was determined using flow cytometry. Proliferation was determined with a CFSE dilution assay. RESULTS CD127 was not decreased on Th17 cells from HAART-controlled HIV individuals, in fact, the percentage of Th17 cells that express CD127 was increased in treated HIV individuals. Furthermore, Th17 cells from HAART-controlled individuals, have normal IL-7-induced STAT5 and Bcl-2 responses, but vastly decreased proliferative responses. CONCLUSION This reduced IL-7 responsiveness may explain the lack of Th17 cell recovery and ongoing systemic immune activation that persists despite well treated HIV infection.
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Chaudhary O, Narayan V, Lelis F, Linz B, Watkins M, Veazey R, Aldovini A. Inhibition of p38 MAPK in combination with ART reduces SIV-induced immune activation and provides additional protection from immune system deterioration. PLoS Pathog 2018; 14:e1007268. [PMID: 30161247 PMCID: PMC6135519 DOI: 10.1371/journal.ppat.1007268] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 09/12/2018] [Accepted: 08/08/2018] [Indexed: 12/12/2022] Open
Abstract
Differences in immune activation were identified as the most significant difference between AIDS-susceptible and resistant species. p38 MAPK, activated in HIV infection, is key to induction of interferon-stimulated genes and cytokine-mediated inflammation and is associated with some of the pathology produced by HIV or SIV infection in AIDS-susceptible primates. As small molecule p38 MAPK inhibitors are being tested in human trials for inflammatory diseases, we evaluated the effects of treating SIV-infected macaques with the p38 MAPK inhibitor PH-797804 in conjunction with ART. PH-797804 had no side effects, did not impact negatively the antiviral immune response and, used alone, had no significant effect on levels of immune activation and did not reduced the viremia. When administered with ART, it significantly reduced numerous immune activation markers compared to ART alone. CD38+/HLA-DR+ and Ki-67+ T-cell percentages in blood, lymph node and rectal CD4+ and CD8+ T cells, PD-1 expression in CD8+ T cells and plasma levels of IFNα, IFNγ, TNFα, IL-6, IP-10, sCD163 and C-reactive protein were all significantly reduced. Significant preservation of CD4+, CD4+ central memory, CD4+/IL-22+ and CD4+/IL-17+ T-cell percentages and improvement of Th17/Treg ratio in blood and rectal mucosa were also observed. Importantly, the addition of PH-797804 to ART initiated during chronic SIV infection reduced immune activation and restored immune system parameters to the levels observed when ART was initiated on week 1 after infection. After ART interruption, viremia rebounded in a similar fashion in all groups, regardless of when ART was initiated. We concluded that the inhibitor PH-797804 significantly reduced, even if did not normalized, the immune activation parameters evaluated during ART treatment, improved preservation of critical populations of the immune system targeted by SIV, and increased the efficacy of ART treatment initiated in chronic infection to levels similar to those observed when initiated in acute infection but did not affect positively or negatively viral reservoirs. The hallmark of Human Immunodeficiency Virus and Simian Immunodeficiency Virus infection in disease-susceptible species is the progressive decline of the CD4+ T cell population and heightened immune activation, which by itself can contribute to CD4+ T-cell death. The cellular pathway regulated by p38 MAPK, which is activated in HIV and SIV infection, can contribute significantly to immune activation. We tested in SIV-infected macaques a p38 MAPK inhibitor in combination with anti-retroviral therapy. This drug is already being evaluated in humans for treatment of immune activation associated with other diseases. We found that, when combined with antiretroviral therapy, the inhibitor PH-797804 significantly reduced a few parameters of SIV-induced immune activation and improved preservation of critical populations of the immune system targeted by SIV, but did not modulate viral reservoirs. Importantly, the addition of the inhibitor to anti-retroviral therapy during the chronic phase of the infection, which is the time when most HIV-infected individuals initiate treatment, permitted a more significant preservation of the immune system compared to antiretroviral therapy alone that was similar to that observed when anti-retroviral therapy was initiated in the acute phase of the infection, which rarely occurs in HIV infection.
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Affiliation(s)
- Omkar Chaudhary
- Boston Children’s Hospital, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston MA, United States of America
| | - Vivek Narayan
- Boston Children’s Hospital, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston MA, United States of America
| | - Felipe Lelis
- Boston Children’s Hospital, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston MA, United States of America
| | - Brandon Linz
- Boston Children’s Hospital, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston MA, United States of America
| | - Meagan Watkins
- Tulane National Primate Research Center, Division of Comparative Pathology, Covington LA, United States of America
| | - Ronald Veazey
- Tulane National Primate Research Center, Division of Comparative Pathology, Covington LA, United States of America
| | - Anna Aldovini
- Boston Children’s Hospital, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston MA, United States of America
- * E-mail:
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Clark E, Nava B, Caputi M. Tat is a multifunctional viral protein that modulates cellular gene expression and functions. Oncotarget 2018; 8:27569-27581. [PMID: 28187438 PMCID: PMC5432358 DOI: 10.18632/oncotarget.15174] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/24/2017] [Indexed: 12/02/2022] Open
Abstract
The human immunodeficiency virus type I (HIV-1) has developed several strategies to condition the host environment to promote viral replication and spread. Viral proteins have evolved to perform multiple functions, aiding in the replication of the viral genome and modulating the cellular response to the infection. Tat is a small, versatile, viral protein that controls transcription of the HIV genome, regulates cellular gene expression and generates a permissive environment for viral replication by altering the immune response and facilitating viral spread to multiple tissues. Studies carried out utilizing biochemical, cellular, and genomic approaches show that the expression and activity of hundreds of genes and multiple molecular networks are modulated by Tat via multiple mechanisms.
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Affiliation(s)
- Evan Clark
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Brenda Nava
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Massimo Caputi
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
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Bortell N, Basova L, Najera JA, Morsey B, Fox HS, Marcondes MCG. Sirtuin 1-Chromatin-Binding Dynamics Points to a Common Mechanism Regulating Inflammatory Targets in SIV Infection and in the Aging Brain. J Neuroimmune Pharmacol 2017; 13:163-178. [PMID: 29280055 DOI: 10.1007/s11481-017-9772-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/20/2017] [Indexed: 12/20/2022]
Abstract
Microglia and macrophages are the main non-neuronal subsets of myeloid origin in the brain, and are critical regulators in neurodegenerative disorders, where inflammation is a key factor. Since HIV infection results in neurological perturbations that are similar to those in aging, we examined microglial and infiltrating myeloid subsets in the search for changes that might resemble the ones in aging. For that, we used the SIV infection in rhesus macaques to model neuroAIDS. We found that Sirt-1, a molecule that impacts survival and health in many models, was decreased in cell preparations containing a majority of microglia and myeloid cells from the brain of infected macaques. The role of Sirt-1 in neuroAIDS is unknown. We hypothesized that Sirt-1 silencing functions are affected by SIV. Mapping of Sirt-1 binding patterns to chromatin revealed that the number of Sirt-1-bound genes was 29.6% increased in myeloid cells from infected animals with mild or no detectable neuropathology, but 51% was decreased in severe neuropathology, compared to controls. Importantly, Sirt-1-bound genes in controls largely participate in neuroinflammation. Promoters of type I IFN pathway genes IRF7, IRF1, IFIT1, and AIF1, showed Sirt-1 binding in controls, which was consistently lost after infection, together with higher transcription. Loss of Sirt-1 binding was also found in brains from old uninfected animals, suggesting a common regulation. The role of Sirt-1 in regulating these inflammatory markers was confirmed in two different in vitro models, where Sirt-1 blockage modulated IRF7, IRF1 and AIF1 levels both in human macrophage cell lines and in human blood-derived monocytes from various normal donors, stimulated with a TLR9 agonist. Our data suggests that Sirt-1-inflammatory gene silencing is disturbed by SIV infection, resembling aging in brains. These findings may impact our knowledge on the contribution of myeloid subsets to the neurological consequences of HIV infection, aggravated and overlapping with the aging process.
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Affiliation(s)
- Nikki Bortell
- Molecular and Cellular Neurosciences Department, The Scripps Research Institute, La Jolla, CA, USA
| | - Liana Basova
- Molecular and Cellular Neurosciences Department, The Scripps Research Institute, La Jolla, CA, USA.,San Diego Biomedical Research Institute, 10865 Road to Cure, Suite 100, San Diego, CA, 92121, USA
| | - Julia A Najera
- Molecular and Cellular Neurosciences Department, The Scripps Research Institute, La Jolla, CA, USA
| | - Brenda Morsey
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198-5800, USA
| | - Howard S Fox
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198-5800, USA
| | - Maria Cecilia Garibaldi Marcondes
- Molecular and Cellular Neurosciences Department, The Scripps Research Institute, La Jolla, CA, USA. .,San Diego Biomedical Research Institute, 10865 Road to Cure, Suite 100, San Diego, CA, 92121, USA.
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11
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Mechanism of Interferon-Stimulated Gene Induction in HIV-1-Infected Macrophages. J Virol 2017; 91:JVI.00744-17. [PMID: 28768867 DOI: 10.1128/jvi.00744-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/23/2017] [Indexed: 12/20/2022] Open
Abstract
Viruses manipulate the complex interferon and interferon-stimulated gene (ISG) system in different ways. We have previously shown that HIV inhibits type I and III interferons in its key target cells but directly stimulates a subset of >20 ISGs in macrophages and dendritic cells, many of which are antiviral. Here, we examine the mechanism of induction of ISGs and show this occurs in two phases. The first phase was transient (0 to 24 h postinfection [hpi]), induced mainly by extracellular vesicles and one of its component proteins, HSP90α, contained within the HIV inoculum. The second, dominant, and persistent phase (>48 hpi) was induced via newly transcribed HIV RNA and sensed via RIGI, as shown by the reduction in ISG expression after the knockdown of the RIGI adaptor, MAVS, by small interfering RNA (siRNA) and the inhibition of both the initiation and elongation of HIV transcription by short hairpin RNA (shRNA) transcriptional silencing. We further define the induction pathway, showing sequential HIV RNA stimulation via Tat, RIGI, MAVS, IRF1, and IRF7, also identified by siRNA knockdown. IRF1 also plays a key role in the first phase. We also show that the ISGs IFIT1 to -3 inhibit HIV production, measured as extracellular infectious virus. All induced antiviral ISGs probably lead to restriction of HIV replication in macrophages, contributing to a persistent, noncytopathic infection, while the inhibition of interferon facilitates spread to adjacent cells. Both may influence the size of macrophage HIV reservoirs in vivo Elucidating the mechanisms of ISG induction may help in devising immunotherapeutic strategies to limit the size of these reservoirs.IMPORTANCE HIV, like other viruses, manipulates the antiviral interferon and interferon-stimulated gene (ISG) system to facilitate its initial infection and establishment of viral reservoirs. HIV specifically inhibits all type I and III interferons in its target cells, including macrophages, dendritic cells, and T cells. It also induces a subset of over 20 ISGs of differing compositions in each cell target. This occurs in two temporal phases in macrophages. Extracellular vesicles contained within the inoculum induce the first, transient phase of ISGs. Newly transcribed HIV RNA induce the second, dominant ISG phase, and here, the full induction pathway is defined. Therefore, HIV nucleic acids, which are potent inducers of interferon and ISGs, are initially concealed, and antiviral ISGs are not fully induced until replication is well established. These antiviral ISGs may contribute to persistent infection in macrophages and to the establishment of viral reservoirs in vivo.
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12
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Gajanayaka N, O'Hara S, Konarski Y, Fernandes J, Muthumani K, Kozlowski M, Angel JB, Kumar A. HIV and HIV-Tat inhibit LPS-induced IL-27 production in human macrophages by distinct intracellular signaling pathways. J Leukoc Biol 2017; 102:925-939. [PMID: 28698313 DOI: 10.1189/jlb.4a0716-332rr] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 07/09/2017] [Accepted: 07/11/2017] [Indexed: 11/24/2022] Open
Abstract
Monocyte-derived Mϕs (MDMs) from HIV-infected patients and MDM infected in vitro with HIV exhibit a reduced ability to secrete various cytokines, including IL-12. Recently, IL-27, an IL-12 family cytokine, was shown to inhibit HIV replication in Mϕ. Whether HIV infection or HIV accessory protein(s) impact IL-27 production in Mϕs remains unknown. Herein, we show that in vitro HIV infection, as well as intracellular HIV-Tat (Tat) and Tat peptides, inhibit LPS-induced IL-27 production in human MDMs, suggesting impairment of the TLR4 signaling pathway. To understand the signaling pathways governing HIV or Tat-mediated inhibition of LPS-induced IL-27 production, we first demonstrated that p38 MAPK, PI3K, Src-homology region 2 domain-containing tyrosine phosphatase 1 (SHP-1), and Src kinases regulate LPS-induced IL-27 production in MDMs. Tat caused down-regulation of TNFR-associated factor (TRAF)-6 and inhibitor of apoptosis 1 (cIAP-1) and subsequently decreased phosphorylation of downstream PI3K and p38 MAPKs, which were implicated in LPS-induced IL-27 production. Whereas SHP-1 and Src kinases regulated LPS-induced IL-27 production, Tat did not inhibit these kinases, suggesting that they were not involved in Tat-mediated inhibition of LPS-induced IL-27 production. In contrast to Tat, in vitro HIV infection of MDM inhibited LPS-induced IL-27 production via inhibition of p38 MAPK activation. Overall, HIV and Tat inhibit LPS-induced IL-27 production in human macrophages via distinct mechanisms: Tat through the inhibition of cIAP-1-TRAF-6 and subsequent inhibition of PI3K and p38 MAPKs, whereas HIV through the inhibition of p38 MAPK activation.
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Affiliation(s)
- Niranjala Gajanayaka
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Shifawn O'Hara
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Yulia Konarski
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Jason Fernandes
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Kar Muthumani
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Maya Kozlowski
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Jonathan B Angel
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; and
| | - Ashok Kumar
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario, Canada; .,Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.,Department Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada
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13
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Le Douce V, Ait-Amar A, Forouzan Far F, Fahmi F, Quiel J, El Mekdad H, Daouad F, Marban C, Rohr O, Schwartz C. Improving combination antiretroviral therapy by targeting HIV-1 gene transcription. Expert Opin Ther Targets 2016; 20:1311-1324. [PMID: 27266557 DOI: 10.1080/14728222.2016.1198777] [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] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Combination Antiretroviral Therapy (cART) has not allowed the cure of HIV. The main obstacle to HIV eradication is the existence of quiescent reservoirs. Several other limitations of cART have been described, such as strict life-long treatment and high costs, restricting it to Western countries, as well as the development of multidrug resistance. Given these limitations and the impetus to find a cure, the development of new treatments is necessary. Areas covered: In this review, we discuss the current status of several efficient molecules able to suppress HIV gene transcription, including NF-kB and Tat inhibitors. We also assess the potential of new proteins belonging to the intriguing DING family, which have been reported to have potential anti-HIV-1 activity by inhibiting HIV gene transcription. Expert opinion: Targeting HIV-1 gene transcription is an alternative approach, which could overcome cART-related issues, such as the emergence of multidrug resistance. Improving cART will rely on the identification and characterization of new actors inhibiting HIV-1 transcription. Combining such efforts with the use of new technologies, the development of new models for preclinical studies, and improvement in drug delivery will considerably reduce drug toxicity and thus increase patient adherence.
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Affiliation(s)
- Valentin Le Douce
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France.,b IUT de Schiltigheim , Schiltigheim , France.,c UCD Centre for Research in Infectious Diseases (CRID) School of Medicine and Medical Science , University College Dublin , Dublin 4 , Ireland
| | - Amina Ait-Amar
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France
| | - Faezeh Forouzan Far
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France
| | - Faiza Fahmi
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France
| | - Jose Quiel
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France
| | - Hala El Mekdad
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France
| | - Fadoua Daouad
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France
| | - Céline Marban
- d Faculté de Chirurgie Dentaire , Inserm UMR 1121 , Strasbourg , France
| | - Olivier Rohr
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France.,b IUT de Schiltigheim , Schiltigheim , France.,e Institut Universitaire de France , Paris , France
| | - Christian Schwartz
- a Institut de Parasitologie et de Pathologie Tropicale, EA7292 , Université de Strasbourg , Strasbourg , France.,b IUT de Schiltigheim , Schiltigheim , France
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14
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Yang F, Xu Z, Duan S, Luo M. MicroRNA-541 promotes the proliferation of vascular smooth muscle cells by targeting IRF7. Am J Transl Res 2016; 8:506-515. [PMID: 27158343 PMCID: PMC4846900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 12/30/2015] [Indexed: 06/05/2023]
Abstract
MiRNAs play crucial roles in abnormal proliferation and invasion of VSMCs. However, the roles and mechanisms of miRNAs in VSMCs are not fully understood. In our study, we demonstrated that PDGF-BB and serum induced proliferation of VSMCs led to the upregulation of miR-541. We also showed that overexpression of miR-541 promoted VSMC proliferation and invasion. In addition, Interferon regulatory factor 7 (IRF7) was found to be a potential target of miR-541 and upregulation of IRF7 could inhibit VSMC proliferation. Restored expression of miR-541 promoted IRF7-inhibited VSMCs proliferation. In conclusion, these findings suggest that inhibitors targeting miR-541 or its specific downstream molecules may be therapeutic strategy for VSMC growth-related diseases.
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Affiliation(s)
- Fang Yang
- Department of Cardiology, Yantaishan Hospital of YantaiYantai 264001, Shandong, China
| | - Zonglei Xu
- Department of Cardiology, Liaocheng People’s HospitalLiaocheng 252000, Shandong, China
| | - Shaobin Duan
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Key Lab of Kidney Disease and Blood Purification in HunanChangsha 410011, Hunan, China
| | - Min Luo
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Key Lab of Kidney Disease and Blood Purification in HunanChangsha 410011, Hunan, China
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15
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Reeder JE, Kwak YT, McNamara RP, Forst CV, D'Orso I. HIV Tat controls RNA Polymerase II and the epigenetic landscape to transcriptionally reprogram target immune cells. eLife 2015; 4. [PMID: 26488441 PMCID: PMC4733046 DOI: 10.7554/elife.08955] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/20/2015] [Indexed: 12/22/2022] Open
Abstract
HIV encodes Tat, a small protein that facilitates viral transcription by binding an RNA structure (trans-activating RNA [TAR]) formed on nascent viral pre-messenger RNAs. Besides this well-characterized mechanism, Tat appears to modulate cellular transcription, but the target genes and molecular mechanisms remain poorly understood. We report here that Tat uses unexpected regulatory mechanisms to reprogram target immune cells to promote viral replication and rewire pathways beneficial for the virus. Tat functions through master transcriptional regulators bound at promoters and enhancers, rather than through cellular ‘TAR-like’ motifs, to both activate and repress gene sets sharing common functional annotations. Despite the complexity of transcriptional regulatory mechanisms in the cell, Tat precisely controls RNA polymerase II recruitment and pause release to fine-tune the initiation and elongation steps in target genes. We propose that a virus with a limited coding capacity has optimized its genome by evolving a small but ‘multitasking’ protein to simultaneously control viral and cellular transcription. DOI:http://dx.doi.org/10.7554/eLife.08955.001 The human immunodeficiency virus (HIV) reproduces and spreads throughout the body by hijacking human immune cells and causing them to copy the virus’s genetic information. As the virus multiplies, it also causes the death of the immune system cells that help the human body recognize and eliminate viruses. This allows the virus to multiply unchecked. Studies of the genetic material of HIV – which is in the form of single-stranded RNA molecules and contains only a handful of genes – have begun to reveal how the virus can wreak such havoc to the human immune system. A small protein encoded by the virus, called Tat, boosts the expression of HIV genes in infected immune cells by binding to a structure that forms on newly synthesized viral RNAs. Recent evidence suggests that HIV also changes the expression of human genes to make immune cells more hospitable to the virus. However, it was not known exactly which specific genes are targeted, or how the virus alters their expression. Now, Reeder, Kwak et al. reveal how the Tat protein alters the expression of more than 400 human genes. Rather than bind to the same structure seen in newly forming HIV RNAs, Tat turns on or off the expression of its human target genes by interacting with proteins that regulate human gene expression. In doing so, Tat is able to precisely control the activity of an enzyme called RNA Polymerase II that is necessary for the early steps of gene expression. Tat’s multitasking ability – boosting HIV gene expression at the same time as reprogramming human gene expression – helps explain how a virus with so little genetic material of its own can perform such a wide range of activities in infected cells. The work of Reeder, Kwak et al. suggests that Tat reshapes the human genome to position target genes in ways that allow them to be efficiently turned on or off. Future studies will further reveal how Tat accomplishes this genome remodeling during different stages of infection. In addition, further research is also necessary to look closely into the sets of genes targeted by Tat to find patterns of genes that work together to alter cell behavior, and investigate how these new behaviors allow HIV to thrive. DOI:http://dx.doi.org/10.7554/eLife.08955.002
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Affiliation(s)
- Jonathan E Reeder
- Department of Biological Sciences, University of Texas at Dallas, Richardson, United States.,Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Youn-Tae Kwak
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ryan P McNamara
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Christian V Forst
- Department of Genetics and Genomic Sciences, Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Iván D'Orso
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
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16
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Liu Y, Shi L, Liu C, Zhu G, Li H, Zhao H, Li S. Effect of combination therapy of propofol and sevoflurane on MAP2K3 level and myocardial apoptosis induced by ischemia-reperfusion in rats. Int J Clin Exp Med 2015; 8:6427-6435. [PMID: 26131269 PMCID: PMC4483982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 03/26/2015] [Indexed: 06/04/2023]
Abstract
To investigate the mechanism of combination therapy of propofol and sevoflurane on MAP2K3 level and myocardial apoptosis induced by ischemia-reperfusion (IR) in rat. A total of 30 SD rats were randomly separated into 3 groups: normal, IR (ligation of left coronary artery), and IR+ propofol and sevoflurane (IR+P+S). Different methods were used to detect the serum index associated IR injury. TUNEL assay was used to analyze the apoptotic cells of rat heart tissues. qRT-PCR was used to analyze the mRNA levels of cell apoptosis related proteins such as Bcl-2, Bax, and MAP2K3. Western blotting was used to detect the expression of Bcl-2, Bax, MAP2K3, and Caspase-3 of heart tissues. Compared with normal group, serum LDH, cTnI, and CK-MB levels in IR group were significantly increased with time increasing (P<0.05), while that in IR+P+S group were significantly decreased compared with that in IR group (P<0.05). The percentage of apoptotic cells of heart tissue in IR+P+S group was larger than that in IR group (P<0.05). Compared with IR group, mRNA expression of MAP2K3 and Bax were significantly decreased with Bcl-2 was significantly increased in IR+P+S group (P<0.05). Also, expression of MAP2K3, Caspase-3, and Bcl-2 in IR+P+S group were statistically lower while Bax was statistically higher than that in IR group (P<0.05). Our study suggested that combination therapy of propofol and sevoflurane may protect myocardial cells from damage during IR through decreasing MAP2K3 level and reducing cell apoptosis via Bcl-2/Bax pathway.
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Affiliation(s)
- Yanqin Liu
- Department of Anesthesiology, Children’s Hospital of Hebei ProvenceHebei Provence, China
| | - Lei Shi
- Department of Anesthesiology, Children’s Hospital of Hebei ProvenceHebei Provence, China
| | - Chunyi Liu
- Department of Anesthesiology, Children’s Hospital of Hebei ProvenceHebei Provence, China
| | - Guiyun Zhu
- Department of Pathology, Chest Hospital of Hebei ProvenceHebei Provence, China
| | - Hao Li
- Department of Anesthesiology, Children’s Hospital of Hebei ProvenceHebei Provence, China
| | - Haitao Zhao
- Department of Anesthesiology, Children’s Hospital of Hebei ProvenceHebei Provence, China
| | - Suling Li
- Department of Anesthesiology, Children’s Hospital of Hebei ProvenceHebei Provence, China
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17
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Pulliam L. Cognitive consequences of a sustained monocyte type 1 IFN response in HIV-1 infection. Curr HIV Res 2015; 12:77-84. [PMID: 24862334 DOI: 10.2174/1570162x12666140526113544] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 11/18/2013] [Accepted: 11/18/2013] [Indexed: 12/16/2022]
Abstract
With successful antiretroviral therapy, HIV-1-infected subjects can achieve undetectable peripheral viral loads and immune homeostasis. However, in a subset of individuals on therapy, peripheral monocytes have a gene expression profile characteristic of a type 1 interferon α (IFN) response. This type 1 IFN response correlates with a number of pathogenic conditions including neural cell injury and in combination with HCV infection, cognitive impairment. Lessons from the non-human primate models of pathogenic and nonpathogenic SIV suggest that returning the initial IFN spike in acute SIV infection to normal allows the immune system to control infection and return to homeostasis. An IFN "alarm" signature, defined as monocyte activation with overexpression of the type1 IFN genes IFI27 and CD169, would be useful for identifying a subset of subjects with HIV-1 infection that could progress to a number of pathologies associated with immune activation including cognitive dysfunction. This strategy is being actively pursued for autoimmune diseases that are characterized by an IFN signature. Therapies to block the IFN signature are under investigation as a means to reset the immune system and in a subset of HIV-1-infected subjects may be an adjuvant to standard antiviral therapy to return cognitive function.
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Affiliation(s)
- Lynn Pulliam
- Veterans Affairs Medical Center (113A), 4150 Clement St., San Francisco, CA 94121, USA.
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18
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Ellegård R, Crisci E, Burgener A, Sjöwall C, Birse K, Westmacott G, Hinkula J, Lifson JD, Larsson M. Complement opsonization of HIV-1 results in decreased antiviral and inflammatory responses in immature dendritic cells via CR3. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 193:4590-601. [PMID: 25252956 PMCID: PMC4201991 DOI: 10.4049/jimmunol.1401781] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 08/25/2014] [Indexed: 11/19/2022]
Abstract
Immature dendritic cells (iDCs) in genital and rectal mucosa may be one of the first cells to come into contact with HIV-1 during sexual transmission of virus. HIV-1 activates the host complement system, which results in opsonization of virus by inactivated complement fragments, for example, iC3b. We investigated antiviral and inflammatory responses induced in human iDCs after exposure to free HIV-1 (F-HIV), complement-opsonized HIV-1 (C-HIV), and complement and Ab-opsonized HIV-1 (CI-HIV). F-HIV gave rise to a significantly higher expression of antiviral factors such as IFN-β, myxovirus resistance protein A, and IFN-stimulated genes, compared with C-HIV and CI-HIV. Additionally, F-HIV induced inflammatory factors such as IL-1β, IL-6, and TNF-α, whereas these responses were weakened or absent after C-HIV or CI-HIV exposure. The responses induced by F-HIV were TLR8-dependent with subsequent activation of IFN regulatory factor 1, p38, ERK, PI3K, and NF-κB pathways, whereas these responses were not induced by C-HIV, which instead induced activation of IFN regulatory factor 3 and Lyn. This modulation of TLR8 signaling was mediated by complement receptor 3 and led to enhanced infection. The impact that viral hijacking of the complement system has on iDC function could be an important immune evasion mechanism used by HIV-1 to establish infection in the host.
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Affiliation(s)
- Rada Ellegård
- Division of Molecular Virology, Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden
| | - Elisa Crisci
- Division of Molecular Virology, Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden
| | - Adam Burgener
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada; National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba R3E 3R2, Canada
| | - Christopher Sjöwall
- Division of Rheumatology/Autoimmunity and Immune Regulation Unit, Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden; and
| | - Kenzie Birse
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada; National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba R3E 3R2, Canada
| | - Garrett Westmacott
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba R3E 3R2, Canada
| | - Jorma Hinkula
- Division of Molecular Virology, Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden
| | - Jeffrey D Lifson
- Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD 21702
| | - Marie Larsson
- Division of Molecular Virology, Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden;
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19
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Fekete T, Pazmandi K, Szabo A, Bacsi A, Koncz G, Rajnavölgyi E. The antiviral immune response in human conventional dendritic cells is controlled by the mammalian target of rapamycin. J Leukoc Biol 2014; 96:579-89. [PMID: 25001862 DOI: 10.1189/jlb.2a0114-048rr] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Type I and III IFNs are crucial, soluble components of potent antiviral responses. It has been explored recently that mTOR is involved in the regulation of IFN-α/β production by pDCs, albeit its role in the induction of IFN responses in cDCs remained unrevealed. In this study, we demonstrate that the PI3K/mTOR pathway is indispensable for eliciting intact type I and III IFN responses in moDCs stimulated with polyI:C. The inhibition of mTOR functionality by rapamycin impairs the pIRF3 and also a few members of the MAPK family, suggesting that mTOR contributes to the activation of multiple signaling pathways in the presence of viral antigens. Furthermore, rapamycin-treated moDCs show decreased capacity to prime IFN-γ secretion by naive CD8(+) T-lymphocytes. As in moDCs, mTOR-mediated regulation is also essential for the production of type I and III IFNs in circulating CD1c(+) DCs. To our best knowledge, these results demonstrate for the first time that mTOR has an impact on the functional activities of cDCs via modulating the outcome of IFN secretion.
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Affiliation(s)
- Tünde Fekete
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Kitti Pazmandi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Szabo
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Bacsi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gabor Koncz
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Eva Rajnavölgyi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Kukkonen S, Martinez-Viedma MDP, Kim N, Manrique M, Aldovini A. HIV-1 Tat second exon limits the extent of Tat-mediated modulation of interferon-stimulated genes in antigen presenting cells. Retrovirology 2014; 11:30. [PMID: 24742347 PMCID: PMC4036831 DOI: 10.1186/1742-4690-11-30] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/27/2014] [Indexed: 12/14/2022] Open
Abstract
Background We have shown that HIV-1 Tat interaction with MAP2K3, MAP2K6, and IRF7 promoters is key to IFN-stimulated genes (ISG) activation in immature dendritic cells and macrophages. Results We evaluated how Tat alleles and mutants differ in cellular gene modulation of immature dendritic cells and monocyte-derived macrophages and what similarities this modulation has with that induced by interferons. The tested alleles and mutants modulated to different degrees ISG, without concomitant induction of interferons. The first exon TatSF21-72 and the minimal transactivator TatSF21-58, all modulated genes to a significantly greater extent than full-length wild type, two-exon Tat, indicating that Tat second exon is critical in reducing the innate response triggered by HIV-1 in these cells. Mutants with reduced LTR transactivation had a substantially reduced effect on host gene expression modulation than wild type TatSF2. However, the more potent LTR transactivator TatSF2A58T modulated ISG expression to a lower degree compared to TatSF2. A cellular gene modulation similar to that induced by Tat and Tat mutants in immature dendritic cells could be observed in monocyte-derived macrophages, with the most significant pathways affected by Tat being the same in both cell types. Tat expression in cells deleted of the type I IFN locus or receptor resulted in a gene modulation pattern similar to that induced in primary immature dendritic cells and monocyte-derived macrophages, excluding the involvement of type I IFNs in Tat-mediated gene modulation. ISG activation depends on Tat interaction with MAP2K3, MAP2K6, and IRF7 promoters and a single exon Tat protein more strongly modulated the luciferase activity mediated by MAP2K3, MAP2K6, and IRF7 promoter sequences located 5′ of the RNA start site than the wild type two-exon Tat, while a cysteine and lysine Tat mutants, reduced in LTR transactivation, had negligible effects on these promoters. Chemical inhibition of CDK9 or Sp1 decreased Tat activation of MAP2K3-, MAP2K6-, and IRF7-mediated luciferase transcription. Conclusions Taken together, these data indicate that the second exon of Tat is critical to the containment of the innate response stimulated by Tat in antigen presenting cells and support a role for Tat in stimulating cellular transcription via its interaction with transcription factors present at promoters.
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Affiliation(s)
| | | | | | | | - Anna Aldovini
- Department of Pediatrics, Harvard Medical School, Department of Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
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