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Blot C, Lavernhe M, Lugo-Villarino G, Coulson K, Salon M, Tertrais M, Planès R, Santoni K, Authier H, Jacquemin G, Rahabi M, Parny M, Letron IR, Meunier E, Lefèvre L, Coste A. Leishmania infantum exploits the anti-ferroptosis effects of Nrf2 to escape cell death in macrophages. Cell Rep 2024; 43:114720. [PMID: 39244752 DOI: 10.1016/j.celrep.2024.114720] [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: 10/20/2023] [Revised: 04/04/2024] [Accepted: 08/20/2024] [Indexed: 09/10/2024] Open
Abstract
Macrophages are major host cells for the protozoan Leishmania parasite. Depending on their activation state, they either contribute to the detection and elimination of Leishmania spp. or promote parasite resilience. Here, we report that the activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in macrophages plays a pivotal role in the progression of Leishmania infantum infection by controlling inflammation and redox balance of macrophages. We also highlight the involvement of the NOX2/reactive oxygen species (ROS) axis in early Nrf2 activation and, subsequently, prostaglandin E2 (PGE2)/EP2r signaling in the sustenance of Nrf2 activation upon infection. Moreover, we establish a ferroptosis-like process within macrophages as a cell death program of L. infantum and the protective effect of Nrf2 in macrophages against L. infantum death. Altogether, these results identify Nrf2 as a critical factor for the susceptibility of L. infantum infection, highlighting Nrf2 as a promising pharmacological target for the development of therapeutic approaches for the treatment of visceral leishmaniasis.
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Affiliation(s)
- Clément Blot
- RESTORE UMR 1301-INSERM 5070 CNRS EFS UPS, Toulouse, France
| | | | | | | | - Marie Salon
- RESTORE UMR 1301-INSERM 5070 CNRS EFS UPS, Toulouse, France
| | | | - Rémi Planès
- Institute of Pharmacology and Structural Biology (IPBS), UMR5089 CNRS UPS, Toulouse, France
| | - Karin Santoni
- Institute of Pharmacology and Structural Biology (IPBS), UMR5089 CNRS UPS, Toulouse, France
| | - Hélène Authier
- RESTORE UMR 1301-INSERM 5070 CNRS EFS UPS, Toulouse, France
| | | | - Mouna Rahabi
- RESTORE UMR 1301-INSERM 5070 CNRS EFS UPS, Toulouse, France
| | - Mélissa Parny
- RESTORE UMR 1301-INSERM 5070 CNRS EFS UPS, Toulouse, France
| | | | - Etienne Meunier
- Institute of Pharmacology and Structural Biology (IPBS), UMR5089 CNRS UPS, Toulouse, France
| | - Lise Lefèvre
- RESTORE UMR 1301-INSERM 5070 CNRS EFS UPS, Toulouse, France.
| | - Agnès Coste
- RESTORE UMR 1301-INSERM 5070 CNRS EFS UPS, Toulouse, France.
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2
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Nguyen V, Taine EG, Meng D, Cui T, Tan W. Pharmacological Activities, Therapeutic Effects, and Mechanistic Actions of Trigonelline. Int J Mol Sci 2024; 25:3385. [PMID: 38542359 PMCID: PMC10970276 DOI: 10.3390/ijms25063385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 03/08/2024] [Accepted: 03/14/2024] [Indexed: 04/17/2024] Open
Abstract
Trigonelline (TRG) is a natural polar hydrophilic alkaloid that is found in many plants such as green coffee beans and fenugreek seeds. TRG potentially acts on multiple molecular targets, including nuclear factor erythroid 2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor γ, glycogen synthase kinase, tyrosinase, nerve growth factor, estrogen receptor, amyloid-β peptide, and several neurotransmitter receptors. In this review, we systematically summarize the pharmacological activities, medicinal properties, and mechanistic actions of TRG as a potential therapeutic agent. Mechanistically, TRG can facilitate the maintenance and restoration of the metabolic homeostasis of glucose and lipids. It can counteract inflammatory constituents at multiple levels by hampering pro-inflammatory factor release, alleviating inflammatory propagation, and attenuating tissue injury. It concurrently modulates oxidative stress by the blockage of the detrimental Nrf2 pathway when autophagy is impaired. Therefore, it exerts diverse therapeutic effects on a variety of pathological conditions associated with chronic metabolic diseases and age-related disorders. It shows multidimensional effects, including neuroprotection from neurodegenerative disorders and diabetic peripheral neuropathy, neuromodulation, mitigation of cardiovascular disorders, skin diseases, diabetic mellitus, liver and kidney injuries, and anti-pathogen and anti-tumor activities. Further validations are required to define its specific targeting molecules, dissect the underlying mechanistic networks, and corroborate its efficacy in clinical trials.
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Affiliation(s)
- Vi Nguyen
- Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, SC 29209, USA;
| | | | - Dehao Meng
- Applied Physics Program, California State University San Marcos, San Marcos, CA 92096, USA
| | - Taixing Cui
- Dalton Cardiovascular Research Center, Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65211, USA;
| | - Wenbin Tan
- Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, SC 29209, USA;
- Department of Biomedical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC 29208, USA
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Daskou M, Fotooh Abadi L, Gain C, Wong M, Sharma E, Kombe Kombe AJ, Nanduri R, Kelesidis T. The Role of the NRF2 Pathway in the Pathogenesis of Viral Respiratory Infections. Pathogens 2023; 13:39. [PMID: 38251346 PMCID: PMC10819673 DOI: 10.3390/pathogens13010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/23/2024] Open
Abstract
In humans, acute and chronic respiratory infections caused by viruses are associated with considerable morbidity and mortality. Respiratory viruses infect airway epithelial cells and induce oxidative stress, yet the exact pathogenesis remains unclear. Oxidative stress activates the transcription factor NRF2, which plays a key role in alleviating redox-induced cellular injury. The transcriptional activation of NRF2 has been reported to affect both viral replication and associated inflammation pathways. There is complex bidirectional crosstalk between virus replication and the NRF2 pathway because virus replication directly or indirectly regulates NRF2 expression, and NRF2 activation can reversely hamper viral replication and viral spread across cells and tissues. In this review, we discuss the complex role of the NRF2 pathway in the regulation of the pathogenesis of the main respiratory viruses, including coronaviruses, influenza viruses, respiratory syncytial virus (RSV), and rhinoviruses. We also summarize the scientific evidence regarding the effects of the known NRF2 agonists that can be utilized to alter the NRF2 pathway.
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Affiliation(s)
- Maria Daskou
- Department of Medicine, Division of Infectious Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Leila Fotooh Abadi
- Department of Internal Medicine, Division of Infectious Diseases and Geographic Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (L.F.A.); (R.N.)
| | - Chandrima Gain
- Department of Medicine, Division of Infectious Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Michael Wong
- Department of Medicine, Division of Infectious Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Eashan Sharma
- Department of Medicine, Division of Infectious Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Arnaud John Kombe Kombe
- Department of Internal Medicine, Division of Infectious Diseases and Geographic Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (L.F.A.); (R.N.)
| | - Ravikanth Nanduri
- Department of Internal Medicine, Division of Infectious Diseases and Geographic Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (L.F.A.); (R.N.)
| | - Theodoros Kelesidis
- Department of Medicine, Division of Infectious Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Internal Medicine, Division of Infectious Diseases and Geographic Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (L.F.A.); (R.N.)
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Kaposi's sarcoma-associated herpesvirus (KSHV) utilizes the NDP52/CALCOCO2 selective autophagy receptor to disassemble processing bodies. PLoS Pathog 2023; 19:e1011080. [PMID: 36634147 PMCID: PMC9876383 DOI: 10.1371/journal.ppat.1011080] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 01/25/2023] [Accepted: 12/22/2022] [Indexed: 01/13/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) causes the inflammatory and angiogenic endothelial cell neoplasm, Kaposi's sarcoma (KS). We previously demonstrated that the KSHV Kaposin B (KapB) protein promotes inflammation via the disassembly of cytoplasmic ribonucleoprotein granules called processing bodies (PBs). PBs modify gene expression by silencing or degrading labile messenger RNAs (mRNAs), including many transcripts that encode inflammatory or angiogenic proteins associated with KS disease. Although our work implicated PB disassembly as one of the causes of inflammation during KSHV infection, the precise mechanism used by KapB to elicit PB disassembly was unclear. Here we reveal a new connection between the degradative process of autophagy and PB disassembly. We show that both latent KSHV infection and KapB expression enhanced autophagic flux via phosphorylation of the autophagy regulatory protein, Beclin. KapB was necessary for this effect, as infection with a recombinant virus that does not express the KapB protein did not induce Beclin phosphorylation or autophagic flux. Moreover, we showed that PB disassembly mediated by KSHV or KapB, depended on autophagy genes and the selective autophagy receptor NDP52/CALCOCO2 and that the PB scaffolding protein, Pat1b, co-immunoprecipitated with NDP52. These studies reveal a new role for autophagy and the selective autophagy receptor NDP52 in promoting PB turnover and the concomitant synthesis of inflammatory molecules during KSHV infection.
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NRF2 in Cancer: Cross-Talk with Oncogenic Pathways and Involvement in Gammaherpesvirus-Driven Carcinogenesis. Int J Mol Sci 2022; 24:ijms24010595. [PMID: 36614036 PMCID: PMC9820659 DOI: 10.3390/ijms24010595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022] Open
Abstract
Expanding knowledge of the molecular mechanisms at the basis of tumor development, especially the cross-talk between oncogenic pathways, will possibly lead to better tailoring of anticancer therapies. Nuclear factor erythroid 2-related factor 2 (NRF2) plays a central role in cancer progression, not only because of its antioxidant activity but also because it establishes cross-talk with several oncogenic pathways, including Heat Shock Factor1 (HSF1), mammalian target of rapamycin (mTOR), and mutant (mut) p53. Moreover, the involvement of NRF2 in gammaherpesvirus-driven carcinogenesis is particularly interesting. These viruses indeed hijack the NRF2 pathway to sustain the survival of tumor cells in which they establish a latent infection and to avoid a too-high increase of reactive oxygen species (ROS) when these cancer cells undergo treatments that induce viral replication. Interestingly, NRF2 activation may prevent gammaherpesvirus-driven oncogenic transformation, highlighting how manipulating the NRF2 pathway in the different phases of gammaherpesvirus-mediated carcinogenesis may lead to different outcomes. This review will highlight the mechanistic interplay between NRF2 and some oncogenic pathways and its involvement in gammaherpesviruses biology to recapitulate published evidence useful for potential application in cancer therapy.
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Wu W, Hendrix A, Nair S, Cui T. Nrf2-Mediated Dichotomy in the Vascular System: Mechanistic and Therapeutic Perspective. Cells 2022; 11:cells11193042. [PMID: 36231004 PMCID: PMC9563590 DOI: 10.3390/cells11193042] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/25/2022] [Accepted: 09/27/2022] [Indexed: 12/14/2022] Open
Abstract
Nuclear factor-erythroid 2-related factor 2 (Nrf2), a transcription factor, controls the expression of more than 1000 genes that can be clustered into different categories with distinct functions ranging from redox balance and metabolism to protein quality control in the cell. The biological consequence of Nrf2 activation can be either protective or detrimental in a context-dependent manner. In the cardiovascular system, most studies have focused on the protective properties of Nrf2, mainly as a key transcription factor of antioxidant defense. However, emerging evidence revealed an unexpected role of Nrf2 in mediating cardiovascular maladaptive remodeling and dysfunction in certain disease settings. Herein we review the role of Nrf2 in cardiovascular diseases with a focus on vascular disease. We discuss the negative effect of Nrf2 on the vasculature as well as the potential underlying mechanisms. We also discuss the clinical relevance of targeting Nrf2 pathways for the treatment of cardiovascular and other diseases.
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Affiliation(s)
- Weiwei Wu
- School of Basic Medicine, Qingdao Medical College, Qingdao University, Qingdao 266071, China
| | - Andrew Hendrix
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29209, USA
| | - Sharad Nair
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29209, USA
- Columbia VA Health System, Wm. Jennings Bryan Dorn VA Medical Center, Columbia, SC 29209, USA
| | - Taixing Cui
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29209, USA
- Columbia VA Health System, Wm. Jennings Bryan Dorn VA Medical Center, Columbia, SC 29209, USA
- Correspondence: ; Tel.: +1-803-216-3804
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Sapochnik D, Raimondi AR, Medina V, Naipauer J, Mesri EA, Coso O. A major role for Nrf2 transcription factors in cell transformation by KSHV encoded oncogenes. Front Oncol 2022; 12:890825. [PMID: 36212441 PMCID: PMC9534600 DOI: 10.3389/fonc.2022.890825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
Kaposi’s sarcoma (KS) is the most common tumor in AIDS patients. The highly vascularized patient’s skin lesions are composed of cells derived from the endothelial tissue transformed by the KSHV virus. Heme oxygenase-1 (HO-1) is an enzyme upregulated by the Kaposi´s sarcoma-associated herpesvirus (KSHV) and highly expressed in human Kaposi Sarcoma (KS) lesions. The oncogenic G protein-coupled receptor (KSHV-GPCR or vGPCR) is expressed by the viral genome in infected cells. It is involved in KS development, HO-1 expression, and vascular endothelial growth factor (VEGF) expression. vGPCR induces HO-1 expression and HO-1 dependent transformation through the Ga13 subunit of heterotrimeric G proteins and the small GTPase RhoA. We have found several lines of evidence supporting a role for Nrf2 transcription factors and family members in the vGPCR-Ga13-RhoA signaling pathway that converges on the HO-1 gene promoter. Our current information assigns a major role to ERK1/2MAPK pathways as intermediates in signaling from vGPCR to Nrf2, influencing Nrf2 translocation to the cell nucleus, Nrf2 transactivation activity, and consequently HO-1 expression. Experiments in nude mice show that the tumorigenic effect of vGPCR is dependent on Nrf2. In the context of a complete KSHV genome, we show that the lack of vGPCR increased cytoplasmic localization of Nrf2 correlated with a downregulation of HO-1 expression. Moreover, we also found an increase in phospho-Nrf2 nuclear localization in mouse KS-like KSHV (positive) tumors compared to KSHV (negative) mouse KS-like tumors. Our data highlights the fundamental role of Nrf2 linking vGPCR signaling to the HO-1 promoter, acting upon not only HO-1 gene expression regulation but also in the tumorigenesis induced by vGPCR. Overall, these data pinpoint this transcription factor or its associated proteins as putative pharmacological or therapeutic targets in KS.
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Affiliation(s)
- Daiana Sapochnik
- CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
- Departamento de Fisiología, Biología Molecular y Celular, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina
| | - Ana R. Raimondi
- CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
- University of Miami- Center for AIDS Research (UM-CFAR)/Sylvester Comprehensive Cancer Center (CCC) Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Victoria Medina
- CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
- University of Miami- Center for AIDS Research (UM-CFAR)/Sylvester Comprehensive Cancer Center (CCC) Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Julian Naipauer
- CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
- University of Miami- Center for AIDS Research (UM-CFAR)/Sylvester Comprehensive Cancer Center (CCC) Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, FL, United States
- Viral Oncology Program, Sylvester Comprehensive Cancer Center, Miami Center for AIDS Research, Department of Microbiology & Immunology, University of Miami, Miami, FL, United States
| | - Enrique A. Mesri
- University of Miami- Center for AIDS Research (UM-CFAR)/Sylvester Comprehensive Cancer Center (CCC) Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, FL, United States
- Viral Oncology Program, Sylvester Comprehensive Cancer Center, Miami Center for AIDS Research, Department of Microbiology & Immunology, University of Miami, Miami, FL, United States
| | - Omar Coso
- CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
- Departamento de Fisiología, Biología Molecular y Celular, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina
- University of Miami- Center for AIDS Research (UM-CFAR)/Sylvester Comprehensive Cancer Center (CCC) Argentina Consortium for Research and Training in Virally Induced AIDS-Malignancies, University of Miami Miller School of Medicine, Miami, FL, United States
- *Correspondence: Omar Coso,
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Strain-Specific Behavior of Mycobacterium tuberculosis in Interruption of Autophagy Pathway in Human Alveolar Type II Epithelial A549 Cells. IRANIAN BIOMEDICAL JOURNAL 2022; 26:313-23. [PMID: 36000264 PMCID: PMC9432471 DOI: 10.52547/ibj.3586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background: Autophagy induction has been shown to differ in magnitude depending on the mycobacterial species. However, few studies have investigated the specific autophagic capacity of different Mtb strains in ATs. This study aimed to elucidate the host autophagic response to different Mtb strains in ATs responsible for TB in the capital of Iran, Tehran. Methods: A549 cells were infected with three different Mtb clinical isolates (Beijing, NEW1, and CAS1/Delhi) and the reference strain H37Rv. Following RNA extraction, the expression of eight ATG genes, four mycobacterial genes, and three miRNAs was evaluated using quantitative RT-PCR. Results: The results revealed that all four strains influenced the autophagy pathway in various ways at different magnitudes. The Beijing and H37Rv strains could inhibit autophagosome formation, whereas the CAS and NEW1 strains induced autophagosome formation. The expression of genes involved in the fusion of autophagosomes to lysosomes (LAMP1) indicated that all the studied strains impaired the autophagolysosomal fusion; this result is not unexpected as Mtb can block the autophagolysomal fusion. In addition, the Beijing and H37RV strains prevented the formation of autophagic vacuoles, besides mycobacterial targeting of lysosomes and protease activity. Conclusion: This preliminary study improved our understanding of how Mtb manages to overcome the host immune system, such as autophagy, and evaluated the genes used by specific strains during this process. Further studies with a large number of Mtb strains, encompassing the other main Mtb lineages, are inevitable.
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Streptococcus pneumoniae exerts oxidative stress, subverts antioxidant signaling and autophagy in human corneal epithelial cells that is alleviated by tert-Butylhydroquinone. Med Microbiol Immunol 2022; 211:119-132. [PMID: 35325292 DOI: 10.1007/s00430-022-00731-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 03/07/2022] [Indexed: 10/18/2022]
Abstract
Streptococcus pneumoniae is one of the leading causes of bacterial keratitis in the developing world and globally. In the current study, we have determined oxidative stress as pathogenesis of S. pneumoniae infection in corneal tissues and human corneal epithelial cells (HCEC) and explored host immune response of HCEC towards S. pneumoniae. We also determined whether treatment with tert-Butylhydroquinone (tBHQ), a Nrf2 inducer, could alleviate oxidative stress and reduce bacterial cytotoxicity in these cells. Oxidative stress was determined in corneal tissues of patients and HCEC by immunohistochemistry and immunofluorescence analysis, respectively. The expression of antioxidant genes, cytokines and antimicrobial peptides was determined by quantitative PCR. Infection of HCEC by S. pneumoniae was determined by colony-forming units. The autophagy and cell death were determined by fluorescence microscopy. The phosphorylation of signaling proteins was evaluated by immunoblot analysis. S. pneumoniae induced oxidative stress during corneal infections and inhibited antioxidant signaling pathways and immune responses like autophagy. tBHQ aided in restoring Nrf2 activation, reduced reactive oxygen species generation and prevented cytotoxicity and cell death in S. pneumoniae-infected HCEC. tBHQ also induced autophagy in a Nrf2-dependent manner and reduced bacterial survival in HCEC. Increased expression of antimicrobial peptides by tBHQ might have contributed to a reduction of bacterial load and cytotoxicity, as exemplified in LL-37 depleted corneal epithelial cells exposed to S. pneumoniae compared to control siRNA-transfected cells. tBHQ mediates alleviation of oxidative stress induced by S. pneumoniae by activating Nrf2-mediated antioxidant signaling in corneal epithelial cells. tBHQ also enhances expression of antimicrobial peptides in corneal cells and aids in inhibition of bacterial survival and cytotoxicity of HCEC.
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Wang Y, Ma G, Wang XF, Na L, Guo X, Zhang J, Liu C, Du C, Qi T, Lin Y, Wang X. Keap1 recognizes EIAV early accessory protein Rev to promote antiviral defense. PLoS Pathog 2022; 18:e1009986. [PMID: 35139135 PMCID: PMC8863222 DOI: 10.1371/journal.ppat.1009986] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/22/2022] [Accepted: 01/13/2022] [Indexed: 12/17/2022] Open
Abstract
The Nrf2/Keap1 axis plays a complex role in viral susceptibility, virus-associated inflammation and immune regulation in host cells. However, whether or how the Nrf2/Keap1 axis is involved in the interactions between equine lentiviruses and their hosts remains unclear. Here, we demonstrate that the Nrf2/Keap1 axis was activated during EIAV infection. Mechanistically, EIAV-Rev competitively binds to Keap1 and releases Nrf2 from Keap1-mediated repression, leading to the accumulation of Nrf2 in the nucleus and promoting Nrf2 responsive genes transcription. Subsequently, we demonstrated that the Nrf2/Keap1 axis represses EIAV replication via two independent molecular mechanisms: directly increasing antioxidant enzymes to promote effective cellular resistance against EIAV infection, and repression of Rev-mediated RNA transport through direct interaction between Keap1 and Rev. Together, these data suggest that activation of the Nrf2/Keap1 axis mediates a passive defensive response to combat EIAV infection. The Nrf2/Keap1 axis could be a potential target for developing strategies for combating EIAV infection.
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Affiliation(s)
- Yan Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Guanqin Ma
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xue-Feng Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lei Na
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xing Guo
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Jiaqi Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Cong Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Cheng Du
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ting Qi
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuezhi Lin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaojun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
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NRF2 in Viral Infection. Antioxidants (Basel) 2021; 10:antiox10091491. [PMID: 34573123 PMCID: PMC8472116 DOI: 10.3390/antiox10091491] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/29/2022] Open
Abstract
The transcription factor NRF2 is central to redox homeostasis in animal cells and is a well-known driver of chemoresistance in many types of cancer. Recently, new roles have been ascribed to NRF2 which include regulation of antiviral interferon responses and inflammation. In addition, NRF2 is emerging as an important factor in antiviral immunity through interferon-independent mechanisms. In the review, we give an overview of the scientific progress on the involvement and importance of NRF2 in the context of viral infection.
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Leishmania donovani Targets Host Transcription Factor NRF2 To Activate Antioxidant Enzyme HO-1 and Transcriptional Repressor ATF3 for Establishing Infection. Infect Immun 2021; 89:e0076420. [PMID: 33820818 DOI: 10.1128/iai.00764-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We showed previously that antioxidant enzyme heme oxygenase 1 (HO-1) is critical for Leishmania survival in visceral leishmaniasis. HO-1 inhibits host oxidative burst and inflammatory cytokine production, leading to parasite persistence. In the present study, screening of reported HO-1 transcription factors revealed that infection upregulated (4.1-fold compared to control [P < 0.001]) nuclear factor erythroid 2 (NFE2)-related factor 2 (NRF2). Silencing of NRF2 reduced both HO-1 expression and parasite survival. Investigation revealed that infection-induced transient reactive oxygen species (ROS) production dissociated NRF2 from its inhibitor KEAP1 and enabled phosphorylation-dependent nuclear translocation. Both NRF2 and HO-1 silencing in infection increased production of proinflammatory cytokines. But the level was greater in NRF2-silenced cells than in HO-1-silenced ones, suggesting the presence of other targets of NRF2. Another stress responsive transcription factor ATF3 is also induced (4.6-fold compared to control [P < 0.001]) by NRF2 during infection. Silencing of ATF3 reduced parasite survival (59.3% decrease compared to control [P < 0.001]) and increased proinflammatory cytokines. Infection-induced ATF3 recruited HDAC1 into the promoter sites of tumor necrosis factor alpha (TNF-α) and interleukin 12b (IL-12b) genes. Resulting deacetylated histones prevented NF-κB promoter binding, thereby reducing transcription of inflammatory cytokines. Administering the NRF2 inhibitor trigonelline hydrochloride to infected BALB/c mice resulted in reduced HO-1 and ATF3 expression, decreased spleen and liver parasite burdens, and increased proinflammatory cytokine levels. These results suggest that Leishmania upregulates NRF2 to activate both HO-1 and ATF3 for disease progression.
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Tao S, Yang Y, Li J, Wang H, Ma Y. Bixin Attenuates High-Fat Diet-Caused Liver Steatosis and Inflammatory Injury through Nrf2/PPAR α Signals. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6610124. [PMID: 33603948 PMCID: PMC7872754 DOI: 10.1155/2021/6610124] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/29/2020] [Accepted: 01/21/2021] [Indexed: 02/06/2023]
Abstract
Nonalcoholic fatty liver disease is the most common liver disease worldwide. Hepatic steatosis and oxidative stress are the main characteristics of NAFLD (nonalcoholic fatty liver disease), which also affect its prognosis. Bixin acts as novel Nrf2 (NF-E2 p45-related factor 2) activator with the cytoprotection against oxidative stress and inflammation; this study mainly focused on the mechanism of Nrf2 activation by bixin and explored its potential feasibilities in long-term high-fat diet- (HFD-) caused hepatic steatosis and inflammatory response in vitro and in vivo. Bixin was found to activate Nrf2 signals by the modification of critical Keap1 (Kelch-like ECH-associated protein 1) cystine and competitive interaction with Keap1 with upregulating P62 mRNA and protein expression. In human liver cells exposed to FFA (free fatty acid), bixin displayed a pronounced cytoprotective activity with upregulation of Nrf2-mediated gene expression, such as PPARα and its targets related with fatty acid oxidation. In HFD-fed mice, systemic administration of bixin attenuated lipid accumulation, decreased oxidant inflammatory damage in the liver, and reduced circulating lipid levels through Nrf2. Different from most of other established inducers, bixin activated Nrf2 signals through two different mechanisms with safe administration for protection of oxidant inflammatory damage and attenuation of lipid accumulation in the in vivo long-term HFD-fed mice. Bixin represents a prototype Nrf2 activator that displays cytoprotective activity upon system administration targeting hepatic steatosis and oxidant inflammation originating from long-term HFD-fed mice. And bixin-based Nrf2-directed systemic intervention may also provide therapeutic benefit in protecting other organs in the process of metabolic syndrome.
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Affiliation(s)
- Shasha Tao
- Chongqing University Central Hospital & Chongqing Emergency Medical Center, No. 1 Jiankang Road, Yuzhong District, Chongqing 400014, China
- School of Public Health, Medical College of Soochow University, 199 Ren'ai Road, Suzhou 215123, China
| | - Youjing Yang
- School of Public Health, Medical College of Soochow University, 199 Ren'ai Road, Suzhou 215123, China
| | - Jianzhong Li
- Department of Nephrology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China
| | - Hongyan Wang
- Chongqing University Central Hospital & Chongqing Emergency Medical Center, No. 1 Jiankang Road, Yuzhong District, Chongqing 400014, China
| | - Yu Ma
- Chongqing University Central Hospital & Chongqing Emergency Medical Center, No. 1 Jiankang Road, Yuzhong District, Chongqing 400014, China
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Raj EN, Lin Y, Chen C, Liu K, Chao J. Selective Autophagy Pathway of Nanoparticles and Nanodrugs: Drug Delivery and Pathophysiological Effects. ADVANCED THERAPEUTICS 2020. [DOI: 10.1002/adtp.202000085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Emmanuel Naveen Raj
- Institute of Molecular Medicine and Bioengineering National Chiao Tung University Hsinchu 30068 Taiwan
- Department of Biological Science and Technology National Chiao Tung University Hsinchu 30068 Taiwan
| | - Yu‐Wei Lin
- Department of Biological Science and Technology National Chiao Tung University Hsinchu 30068 Taiwan
| | - Chien‐Hung Chen
- Department of Biological Science and Technology National Chiao Tung University Hsinchu 30068 Taiwan
| | - Kuang‐Kai Liu
- Department of Biological Science and Technology National Chiao Tung University Hsinchu 30068 Taiwan
| | - Jui‐I Chao
- Institute of Molecular Medicine and Bioengineering National Chiao Tung University Hsinchu 30068 Taiwan
- Department of Biological Science and Technology National Chiao Tung University Hsinchu 30068 Taiwan
- Center For Intelligent Drug Systems and Smart Bio‐devices National Chiao Tung University Hsinchu 30068 Taiwan
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15
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HACE1, an E3 Ubiquitin Protein Ligase, Mitigates Kaposi's Sarcoma-Associated Herpesvirus Infection-Induced Oxidative Stress by Promoting Nrf2 Activity. J Virol 2019; 93:JVI.01812-18. [PMID: 30787155 DOI: 10.1128/jvi.01812-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/12/2019] [Indexed: 12/14/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV)-induced activation of nuclear factor erythroid 2-related factor 2 (Nrf2) is essential for both the expression of viral genes (latency) and modulation of the host antioxidant machinery. Reactive oxygen species (ROS) are also regulated by the ubiquitously expressed HACE1 protein (HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1), which targets the Rac1 protein for proteasomal degradation, and this blocks the generation of ROS by Rac1-dependent NADPH oxidases. In this study, we examined the role of HACE1 in KSHV infection. Elevated levels of HACE1 expression were observed in de novo KSHV-infected endothelial cells, KSHV latently infected TIVE-LTC and PEL cells, and Kaposi's sarcoma skin lesion cells. The increased HACE1 expression in the infected cells was mediated by KSHV latent protein kaposin A. HACE1 knockdown resulted in high Rac1 and Nox 1 (NADPH oxidase 1) activity, increased ROS (oxidative stress), increased cell death, and decreased KSHV gene expression. Loss of HACE1 impaired KSHV infection-induced phosphoinositide 3-kinase (PI3-K), protein kinase C-ζ (PKC-ζ), extracellular signal-regulated kinase 1/2 (ERK1/2), NF-κB, and Nrf2 activation and nuclear translocation of Nrf2, and it reduced the expression of Nrf2 target genes responsible for balancing the oxidative stress. In the absence of HACE1, glutamine uptake increased in the cells to cope with the KSHV-induced oxidative stress. These findings reveal for the first time that HACE1 plays roles during viral infection-induced oxidative stress and demonstrate that HACE1 facilitates resistance to KSHV infection-induced oxidative stress by promoting Nrf2 activity. Our studies suggest that HACE1 could be a potential target to induce cell death in KSHV-infected cells and to manage KSHV infections.IMPORTANCE ROS play important roles in several cellular processes, and increased ROS cause several adverse effects. KSHV infection of endothelial cells induces ROS, which facilitate virus entry by amplifying the infection-induced host cell signaling cascade, which, in turn, induces the nuclear translocation of phospho-Nrf2 protein to regulate the expression of antioxidative genes and viral genes. The present study demonstrates that KSHV infection induces the E3 ligase HACE1 protein to regulate KSHV-induced oxidative stress by promoting the activation of Nrf2 and nuclear translocation. Absence of HACE1 results in increased ROS and cellular death and reduced nuclear Nrf2, antioxidant, and viral gene expression. Together, these studies suggest that HACE1 can be a potential target to induce cell death in KSHV-infected cells.
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16
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Wang L, Howell MEA, Sparks-Wallace A, Hawkins C, Nicksic CA, Kohne C, Hall KH, Moorman JP, Yao ZQ, Ning S. p62-mediated Selective autophagy endows virus-transformed cells with insusceptibility to DNA damage under oxidative stress. PLoS Pathog 2019; 15:e1007541. [PMID: 31017975 PMCID: PMC6502431 DOI: 10.1371/journal.ppat.1007541] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 05/06/2019] [Accepted: 03/26/2019] [Indexed: 12/26/2022] Open
Abstract
DNA damage response (DDR) and selective autophagy both can be activated by reactive oxygen/nitrogen species (ROS/RNS), and both are of paramount importance in cancer development. The selective autophagy receptor and ubiquitin (Ub) sensor p62 plays a key role in their crosstalk. ROS production has been well documented in latent infection of oncogenic viruses including Epstein-Barr Virus (EBV). However, p62-mediated selective autophagy and its interplay with DDR have not been investigated in these settings. In this study, we provide evidence that considerable levels of p62-mediated selective autophagy are spontaneously induced, and correlate with ROS-Keap1-NRF2 pathway activity, in virus-transformed cells. Inhibition of autophagy results in p62 accumulation in the nucleus, and promotes ROS-induced DNA damage and cell death, as well as downregulates the DNA repair proteins CHK1 and RAD51. In contrast, MG132-mediated proteasome inhibition, which induces rigorous autophagy, promotes p62 degradation but accumulation of the DNA repair proteins CHK1 and RAD51. However, pretreatment with an autophagy inhibitor offsets the effects of MG132 on CHK1 and RAD51 levels. These findings imply that p62 accumulation in the nucleus in response to autophagy inhibition promotes proteasome-mediated CHK1 and RAD51 protein instability. This claim is further supported by the findings that transient expression of a p62 mutant, which is constitutively localized in the nucleus, in B cell lines with low endogenous p62 levels recaptures the effects of autophagy inhibition on CHK1 and RAD51 protein stability. These results indicate that proteasomal degradation of RAD51 and CHK1 is dependent on p62 accumulation in the nucleus. However, small hairpin RNA (shRNA)-mediated p62 depletion in EBV-transformed lymphoblastic cell lines (LCLs) had no apparent effects on the protein levels of CHK1 and RAD51, likely due to the constitutive localization of p62 in the cytoplasm and incomplete knockdown is insufficient to manifest its nuclear effects on these proteins. Rather, shRNA-mediated p62 depletion in EBV-transformed LCLs results in significant increases of endogenous RNF168-γH2AX damage foci and chromatin ubiquitination, indicative of activation of RNF168-mediated DNA repair mechanisms. Our results have unveiled a pivotal role for p62-mediated selective autophagy that governs DDR in the setting of oncogenic virus latent infection, and provide a novel insight into virus-mediated oncogenesis.
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Affiliation(s)
- Ling Wang
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
| | - Mary E. A. Howell
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
| | - Ayrianna Sparks-Wallace
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
| | - Caroline Hawkins
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
| | - Camri A. Nicksic
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
| | - Carissa Kohne
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
| | - Kenton H. Hall
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
| | - Jonathan P. Moorman
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
- The HCV/HIV Program, James H Quillen VA Medical Center, Johnson City, TN, United States of America
| | - Zhi Q. Yao
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
- The HCV/HIV Program, James H Quillen VA Medical Center, Johnson City, TN, United States of America
| | - Shunbin Ning
- Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States of America
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17
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EBV and KSHV Infection Dysregulates Autophagy to Optimize Viral Replication, Prevent Immune Recognition and Promote Tumorigenesis. Viruses 2018; 10:v10110599. [PMID: 30384495 PMCID: PMC6266050 DOI: 10.3390/v10110599] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/22/2018] [Accepted: 10/30/2018] [Indexed: 12/12/2022] Open
Abstract
Autophagy is a catabolic process strongly involved in the immune response, and its dysregulation contributes to the onset of several diseases including cancer. The human oncogenic gammaherpesviruses, Epstein—Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV), manipulate autophagy, either during the de novo infection or during the lytic reactivation, in naturally latently-infected lymphoma cells. In particular, the gammaherpesvirus infection reduces autophagy in immune cells, such as monocytes, resulting in the impairment of cell survival and cell differentiation into dendritic cells (DCs), which are essential for initiating and regulating the immune response. In the case of EBV, the reduction of autophagy in these cells, leading to p62 accumulation, activated the p62-NRF2-antioxidant response, reducing ROS, and further inhibiting autophagy. KSHV inhibits autophagy in monocytes by de-phosphorylating JNK2, altering the calpains–calpastatin balance and increasing the calpain activity responsible for the cleavage of ATG5. To further impair the immune response, KSHV also inhibits autophagy in differentiated DCs by hyper-phosphorylating STAT3. Conversely, when the lytic cycle is induced in vitro in latently-infected lymphoma B cells, both EBV and KSHV promote autophagy to enhance their replication, although the final autophagic steps are blocked through the down-regulation of Rab7. This strategy allows viruses to avoid the destructive environment of lysosomes, and to exploit the autophagic machinery for intracellular transportation. EBV and KSHV encode for proteins that may either inhibit or promote autophagy and, in addition, they can modulate the cellular pathways that control this process. In this review we will discuss the findings that indicate that autophagy is dysregulated by gammaherpesvirus to promote immune suppression, facilitate viral replication and contribute to the onset and maintenance of gammaherpesvirus-associated malignancies.
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18
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Gilardini Montani MS, Santarelli R, Granato M, Gonnella R, Torrisi MR, Faggioni A, Cirone M. EBV reduces autophagy, intracellular ROS and mitochondria to impair monocyte survival and differentiation. Autophagy 2018; 15:652-667. [PMID: 30324853 DOI: 10.1080/15548627.2018.1536530] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
EBV has been reported to impair monocyte in vitro differentiation into dendritic cells (DCs) and reduce cell survival. In this study, we added another layer of knowledge to this topic and showed that these effects correlated with macroautophagy/autophagy, ROS and mitochondrial biogenesis reduction. Of note, autophagy and ROS, although strongly interconnected, have been separately reported to be induced by CSF2/GM-CSF (colony stimulating factor 2) and required for CSF2-IL4-driven monocyte in vitro differentiation into DCs. We show that EBV infects monocytes and initiates a feedback loop in which, by inhibiting autophagy, reduces ROS and through ROS reduction negatively influences autophagy. Mechanistically, autophagy reduction correlated with the downregulation of RAB7 and ATG5 expression and STAT3 activation, leading to the accumulation of SQSTM1/p62. The latter activated the SQSTM1-KEAP1- NFE2L2 axis and upregulated the anti-oxidant response, reducing ROS and further inhibiting autophagy. ROS decrease correlated also with the reduction of mitochondria, the main source of intracellular ROS, achieved by the downregulation of NRF1 and TFAM, mitochondrial biogenesis transcription factors. Interestingly, mitochondria supply membranes and ATP required for autophagy execution, thus their reduction may further reduce autophagy in EBV-infected monocytes. In conclusion, this study shows for the first time that the interconnected reduction of autophagy, intracellular ROS and mitochondria mediated by EBV switches monocyte differentiation into apoptosis, giving new insights into the mechanisms through which this virus reduces immune surveillance. Abbreviations: ACTB: actin beta; ATG5: autophagy related 5; BAF: bafilomycin A1; BECN1: beclin 1; CAT: catalase; CSF2: colony stimulating factor 2; CT: control; CYCS (cytochrome C: somatic); DCs: dendritic cells; EBV: Epstein-Barr virus; GSR: glutathione-disulfide reductase; KEAP1: kelch like ECH associated protein 1; IL4: interleukin 4; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MET: metformin; NAC: N-acetylcysteine; NFE2L2/NRF2 nuclear factor: erythroid 2 like 2; NRF1 (nuclear respiratory factor 1); clPARP1: cleaved poly(ADP-ribose) polymerase; Rapa: Rapamycin; ROS: reactive oxygen species; SQSTM1/p62: sequestosome 1; TFAM: (transcription factor A: mitochondrial); TUBA1A: tubulin alpha 1a.
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Affiliation(s)
- M S Gilardini Montani
- a Department of Experimental Medicine , Sapienza University of Rome, laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome , Italy
| | - R Santarelli
- a Department of Experimental Medicine , Sapienza University of Rome, laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome , Italy
| | - M Granato
- a Department of Experimental Medicine , Sapienza University of Rome, laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome , Italy
| | - R Gonnella
- a Department of Experimental Medicine , Sapienza University of Rome, laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome , Italy
| | - M R Torrisi
- b Department of Clinical and Molecular Medicine , Sapienza University of Rome, laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Italy.,c Sant'Andrea University Hospital , Azienda Ospedaliera Sant'Andrea , Rome , Italy
| | - A Faggioni
- a Department of Experimental Medicine , Sapienza University of Rome, laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome , Italy
| | - M Cirone
- a Department of Experimental Medicine , Sapienza University of Rome, laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome , Italy
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19
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Ramezani A, Nahad MP, Faghihloo E. The role of Nrf2 transcription factor in viral infection. J Cell Biochem 2018; 119:6366-6382. [DOI: 10.1002/jcb.26897] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Ali Ramezani
- Virology DepartmentSchool of MedicineAhvaz Jundishapur University of Medical SciencesAhvazIran
- Hepatitis Research CenterBirjand University of Medical SciencesBirjandIran
| | - Mehdi Parsa Nahad
- Virology DepartmentSchool of MedicineAhvaz Jundishapur University of Medical SciencesAhvazIran
| | - Ebrahim Faghihloo
- Department of MicrobiologySchool of MedicineShahid Beheshti University of Medical SciencesTehranIran
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20
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Buonfiglio LGV, Bagegni M, Borcherding JA, Sieren JC, Caraballo JC, Reger A, Zabner J, Li X, Comellas AP. Protein Kinase Cζ Inhibitor Promotes Resolution of Bleomycin-Induced Acute Lung Injury. Am J Respir Cell Mol Biol 2017; 55:869-877. [PMID: 27486964 DOI: 10.1165/rcmb.2015-0006oc] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Protein kinase Cζ (PKCζ) is highly expressed in the lung, where it plays several regulating roles in the pathogenesis of acute lung injury (ALI). Proliferation and differentiation of integrin β4+ distal lung epithelial progenitor cells seem to play a key role in proper lung regeneration. We investigated the effects of a myristoylated PKCζ inhibitor (PKCζi) in a murine model of bleomycin-induced ALI. After intratracheal injury, we treated mice three times a week with PKCζi or its vehicle, DMSO. We found that mice injured with bleomycin and then treated with PKCζi for one week showed decreased activation of PKCζ, improved lung compliance, and decreased lung protein permeability compared to injured mice treated with DMSO. Mice treated continuously with PKCζi for 6 weeks showed reduced evidence of lung fibrosis by computed tomographic images, decreased lung collagen deposition, and decreased active transforming growth factor-β in the bronchoalveolar lavage fluid. In addition, we found an increased number of lung β4+ cells compared to DMSO at Week 6. Therefore, we grew isolated integrin β4+ lung progenitor cells in the presence of PKCζi or DMSO and found that β4+ cells treated with PKCζi proliferated more in vitro compared to DMSO. We conclude that the use of a PKCζi promotes resolution of lung fibrosis in a bleomycin ALI model and increases the number of β4+ progenitor cells with regenerative potential in the lung.
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Affiliation(s)
- Luis G Vargas Buonfiglio
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
| | - Mosaab Bagegni
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
| | - Jennifer A Borcherding
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
| | | | - Juan C Caraballo
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
| | - Andrew Reger
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
| | - Joseph Zabner
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
| | - Xiaopeng Li
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
| | - Alejandro P Comellas
- 1 Internal Medicine Department, Division of Pulmonary, Critical Care, and Occupational Medicine, and
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21
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Docosahexaenoic Acid Induces Expression of Heme Oxygenase-1 and NAD(P)H:quinone Oxidoreductase through Activation of Nrf2 in Human Mammary Epithelial Cells. Molecules 2017; 22:molecules22060969. [PMID: 28604588 PMCID: PMC6152628 DOI: 10.3390/molecules22060969] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/04/2017] [Accepted: 06/05/2017] [Indexed: 12/30/2022] Open
Abstract
Docosahexaenoic acid (DHA), an ω-3 fatty acid abundant in fish oils, has diverse health beneficial effects, such as anti-oxidative, anti-inflammatory, neuroprotective, and chemopreventive activities. In this study, we found that DHA induced expression of two representative antioxidant/cytoprotective enzymes, heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase (NQO1), in human mammary epithealial (MCF-10A) cells. DHA-induced upregulation of these enzymes was accompanied by enhanced translocation of the redox-sensitive transcription factor Nrf2 into the nucleus and its binding to antioxidant response element. Nrf2 gene silencing by siRNA abolished the DHA-induced expression of HO-1 and NQO1 proteins. When MCF-10A cells were transfected with mutant constructs in which the cysteine 151 or 288 residue of Keap1 was replaced by serine, DHA-induced expression of HO-1 and NQO1 was markedly reduced. Moreover, DHA activated protein kinase C (PKC)δ and induced Nrf2 phosphorylation. DHA-induced phosphorylation of Nrf2 was abrogated by the pharmacological PKCδ inhibitor rottlerin or siRNA knockdown of its gene expression. The antioxidants N-acetyl-l-cysteine and Trolox attenuated DHA-induced activation of PKCδ, phosphorylation of Nrf2, and and its target protein expression. In conclusion, DHA activates Nrf2, possibly through modification of critical Keap1 cysteine 288 residue and PKCδ-mediated phosphorylation of Nrf2, leading to upregulation of HO-1 and NQO1 expression.
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22
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Abstract
The concept of macroautophagy was established in 1963, soon after the discovery of lysosomes in rat liver. Over the 50 years since, studies of liver autophagy have produced many important findings. The liver is rich in lysosomes and possesses high levels of metabolic-stress-induced autophagy, which is precisely regulated by concentrations of hormones and amino acids. Liver autophagy provides starved cells with amino acids, glucose and free fatty acids for use in energy production and synthesis of new macromolecules, and also controls the quality and quantity of organelles such as mitochondria. Although the efforts of early investigators contributed markedly to our current knowledge of autophagy, the identification of autophagy-related genes represented a revolutionary breakthrough in our understanding of the physiological roles of autophagy in the liver. A growing body of evidence has shown that liver autophagy contributes to basic hepatic functions, including glycogenolysis, gluconeogenesis and β-oxidation, through selective turnover of specific cargos controlled by a series of transcription factors. In this Review, we outline the history of liver autophagy study, and then describe the roles of autophagy in hepatic metabolism under healthy and disease conditions, including the involvement of autophagy in α1-antitrypsin deficiency, NAFLD, hepatocellular carcinoma and viral hepatitis.
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Affiliation(s)
- Takashi Ueno
- Laboratory of Proteomics and Biomolecular Science, Research Support Center, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Masaaki Komatsu
- Department of Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata 951-8510, Japan
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23
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Katsuragi Y, Ichimura Y, Komatsu M. Regulation of the Keap1–Nrf2 pathway by p62/SQSTM1. CURRENT OPINION IN TOXICOLOGY 2016. [DOI: 10.1016/j.cotox.2016.09.005] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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24
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Chmura JC, Herold K, Ruffin A, Atuobi T, Fabiyi Y, Mitchell AE, Choi YB, Ehrlich ES. The Itch ubiquitin ligase is required for KSHV RTA induced vFLIP degradation. Virology 2016; 501:119-126. [PMID: 27912080 DOI: 10.1016/j.virol.2016.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 10/19/2016] [Accepted: 11/23/2016] [Indexed: 01/22/2023]
Abstract
Expression of Kaposi's sarcoma herpesvirus vFLIP, a potent activator of NFkB signaling, promotes latency. Inhibition of NFkB signaling promotes lytic reactivation. We previously reported that lytic inducer, RTA, inhibits vFLIP induced NFkB signaling by inducing the degradation of vFLIP via the proteasome. Here we report that the cellular ubiquitin ligase, Itch, is required for RTA induced degradation of vFLIP. Expression of either Itch targeting shRNA or a dominant negative mutant of the ubiquitin ligase both increased the stability of vFLIP in the presence of RTA. Itch potently ubiquitinated vFLIP in vivo and in vitro. We provide evidence for interaction between RTA, vFLIP and Itch and we identified an RTA resistant mutant of vFLIP that is unable to interact with Itch. These observations contribute to our understanding of how RTA counteracts the activities of vFLIP.
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Affiliation(s)
- Jennifer C Chmura
- Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252, USA
| | - Kevin Herold
- Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252, USA
| | - Ayana Ruffin
- Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252, USA
| | - Trudymae Atuobi
- Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252, USA
| | - Yetunde Fabiyi
- Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252, USA
| | - Ashley E Mitchell
- Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252, USA
| | - Young Bong Choi
- Viral Oncology Program, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, 1650 Orleans Street, CRB1, Baltimore, MD 21231, USA
| | - Elana S Ehrlich
- Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252, USA.
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25
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Nuclear Innate Immune DNA Sensor IFI16 Is Degraded during Lytic Reactivation of Kaposi's Sarcoma-Associated Herpesvirus (KSHV): Role of IFI16 in Maintenance of KSHV Latency. J Virol 2016; 90:8822-41. [PMID: 27466416 PMCID: PMC5021400 DOI: 10.1128/jvi.01003-16] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/13/2016] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED IFI16 (interferon gamma-inducible protein 16) recognizes nuclear episomal herpesvirus (Kaposi's sarcoma-associated herpesvirus [KSHV], Epstein-Barr virus [EBV], and herpes simplex virus 1 [HSV-1]) genomes and induces the inflammasome and interferon beta responses. It also acts as a lytic replication restriction factor and inhibits viral DNA replication (human cytomegalovirus [HCMV] and human papillomavirus [HPV]) and transcription (HSV-1, HCMV, and HPV) through epigenetic modifications of the viral genomes. To date, the role of IFI16 in the biology of latent viruses is not known. Here, we demonstrate that knockdown of IFI16 in the latently KSHV-infected B-lymphoma BCBL-1 and BC-3 cell lines results in lytic reactivation and increases in levels of KSHV lytic transcripts, proteins, and viral genome replication. Similar results were also observed during KSHV lytic cycle induction in TREX-BCBL-1 cells with the doxycycline-inducible lytic cycle switch replication and transcription activator (RTA) gene. Overexpression of IFI16 reduced lytic gene induction by the chemical agent 12-O-tetradecoylphorbol-13-acetate (TPA). IFI16 protein levels were significantly reduced or absent in TPA- or doxycycline-induced cells expressing lytic KSHV proteins. IFI16 is polyubiquitinated and degraded via the proteasomal pathway. The degradation of IFI16 was absent in phosphonoacetic acid-treated cells, which blocks KSHV DNA replication and, consequently, late lytic gene expression. Chromatin immunoprecipitation assays of BCBL-1 and BC-3 cells demonstrated that IFI16 binds to KSHV gene promoters. Uninfected epithelial SLK and osteosarcoma U2OS cells transfected with KSHV luciferase promoter constructs confirmed that IFI16 functions as a transcriptional repressor. These results reveal that KSHV utilizes the innate immune nuclear DNA sensor IFI16 to maintain its latency and repression of lytic transcripts, and a late lytic KSHV gene product(s) targets IFI16 for degradation during lytic reactivation. IMPORTANCE Like all herpesviruses, latency is an integral part of the life cycle of Kaposi's sarcoma-associated herpesvirus (KSHV), an etiological agent for many human cancers. Herpesviruses utilize viral and host factors to successfully evade the host immune system to maintain latency. Reactivation is a complex event where the latent episomal viral genome springs back to active transcription of lytic cycle genes. Our studies reveal that KSHV has evolved to utilize the innate immune sensor IFI16 to keep lytic cycle transcription in dormancy. We demonstrate that IFI16 binds to the lytic gene promoter, acts as a transcriptional repressor, and thereby helps to maintain latency. We also discovered that during the late stage of lytic replication, KSHV selectively degrades IFI16, thus relieving transcriptional repression. This is the first report to demonstrate the role of IFI16 in latency maintenance of a herpesvirus, and further understanding will lead to the development of strategies to eliminate latent infection.
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Tao S, Rojo de la Vega M, Quijada H, Wondrak GT, Wang T, Garcia JGN, Zhang DD. Bixin protects mice against ventilation-induced lung injury in an NRF2-dependent manner. Sci Rep 2016; 6:18760. [PMID: 26729554 PMCID: PMC4700431 DOI: 10.1038/srep18760] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 08/26/2015] [Indexed: 12/19/2022] Open
Abstract
Mechanical ventilation (MV) is a therapeutic intervention widely used in the clinic to assist patients that have difficulty breathing due to lung edema, trauma, or general anesthesia. However, MV causes ventilator-induced lung injury (VILI), a condition characterized by increased permeability of the alveolar-capillary barrier that results in edema, hemorrhage, and neutrophil infiltration, leading to exacerbated lung inflammation and oxidative stress. This study explored the feasibility of using bixin, a canonical NRF2 inducer identified during the current study, to ameliorate lung damage in a murine VILI model. In vitro, bixin was found to activate the NRF2 signaling pathway through blockage of ubiquitylation and degradation of NRF2 in a KEAP1-C151 dependent manner; intraperitoneal (IP) injection of bixin led to pulmonary upregulation of the NRF2 response in vivo. Remarkably, IP administration of bixin restored normal lung morphology and attenuated inflammatory response and oxidative DNA damage following MV. This observed beneficial effect of bixin derived from induction of the NRF2 cytoprotective response since it was only observed in Nrf2+/+ but not in Nrf2−/− mice. This is the first study providing proof-of-concept that NRF2 activators can be developed into pharmacological agents for clinical use to prevent patients from lung injury during MV treatment.
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Affiliation(s)
- Shasha Tao
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | | | - Hector Quijada
- Arizona Respiratory Center and Department of Medicine, University of Arizona, Tucson, AZ 85721
| | - Georg T Wondrak
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA.,Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724, USA
| | - Ting Wang
- Arizona Respiratory Center and Department of Medicine, University of Arizona, Tucson, AZ 85721
| | - Joe G N Garcia
- Arizona Respiratory Center and Department of Medicine, University of Arizona, Tucson, AZ 85721
| | - Donna D Zhang
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA.,Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724, USA
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Wakabayashi N, Chartoumpekis DV, Kensler TW. Crosstalk between Nrf2 and Notch signaling. Free Radic Biol Med 2015; 88:158-167. [PMID: 26003520 PMCID: PMC4628857 DOI: 10.1016/j.freeradbiomed.2015.05.017] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/08/2015] [Accepted: 05/12/2015] [Indexed: 12/17/2022]
Abstract
The transcription factor Nrf2 (nuclear factor, erythroid derived 2, like 2) belongs to the CNC-bZip protein family, forming a transcriptosome with its direct heterodimer partner, sMaf, and co-factors such as CBP/p300. Nrf2 binds to one or more AREs (antioxidant response elements) that are located in the gene regulatory regions of the hundreds of Nrf2 target genes. The AREs are key enhancers that are activated in response to endogenous or exogenous stresses to maintain cellular and tissue homeostasis. Data emanating from gene expression microarray analyses comparing Nrf2-disrupted and wild-type mouse embryonic fibroblasts (MEF) showed that expression of Notch1 and Notch-signaling-related genes were decreased in Nrf2-disrupted cells. This observation triggered our research on Nrf2-Notch crosstalk. A functional ARE has been identified upstream of the Notch1 major transcription start site. Furthermore, an Rbpjκ binding site is conserved on the promoters of Nrf2 among animal species. Notch1 is one of the transmembrane Notch family receptors that drive Notch signaling, together with the Rbpjκ transcription factor. After canonically accepting ligands such as Jags and Deltas, the receptor undergoes cleavage to yield the Notch intracellular domain, which translocates to the nucleus. Recent studies using conditional knockout mice indicate that Notch1 as well as Notch2 plays an important role postnatally in liver development and in maintenance of hepatic function. In this review, we summarize current understanding of the role of reciprocal transcriptional regulation between Nrf2 and Notch in adult liver from studies using Nrf2, Keap1, and Notch1 genetically engineered mice.
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Affiliation(s)
- Nobunao Wakabayashi
- Department of Pharmacology & Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Dionysios V Chartoumpekis
- Department of Pharmacology & Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Thomas W Kensler
- Department of Pharmacology & Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Environmental Health Science, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Jiang T, Harder B, Rojo de la Vega M, Wong PK, Chapman E, Zhang DD. p62 links autophagy and Nrf2 signaling. Free Radic Biol Med 2015; 88:199-204. [PMID: 26117325 PMCID: PMC4628872 DOI: 10.1016/j.freeradbiomed.2015.06.014] [Citation(s) in RCA: 434] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 12/15/2022]
Abstract
The Nrf2-Keap1-ARE pathway is a redox and xenobiotic sensitive signaling axis that functions to protect cells against oxidative stress, environmental toxicants, and harmful chemicals through the induction of cytoprotective genes. To enforce strict regulation, cells invest a great deal of energy into the maintenance of the Nrf2 pathway to ensure rapid induction upon cellular insult and rapid return to basal levels once the insult is mitigated. Because of the protective role of Nrf2 transcriptional programs, controlled activation of the pathway has been recognized as a means for chemoprevention. On the other hand, constitutive activation of Nrf2, due to somatic mutations of genes that control Nrf2 degradation, promotes carcinogenesis and imparts chemoresistance to cancer cells. Autophagy, a bulk protein degradation process, is another tightly regulated complex cellular process that functions as a cellular quality control system to remove damaged proteins or organelles. Low cellular nutrient levels can also activate autophagy, which acts to restore metabolic homeostasis through the degradation of macromolecules to provide nutrients. Recently, these two cellular pathways were shown to intersect through the direct interaction between p62 (an autophagy adaptor protein) and Keap1 (the Nrf2 substrate adaptor for the Cul3 E3 ubiquitin ligase). Dysregulation of autophagy was shown to result in prolonged Nrf2 activation in a p62-dependent manner. In this review, we will discuss the progress that has been made in dissecting the intersection of these two pathways and the potential tumor-promoting role of prolonged Nrf2 activation.
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Affiliation(s)
- Tao Jiang
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Bryan Harder
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | | | - Pak K Wong
- Department of Aerospace and Mechanical Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Eli Chapman
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Donna D Zhang
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ 85721, USA; Arizona Cancer Center, University of Arizona, Tucson, Arizona 85724, USA.
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Activated Nrf2 Interacts with Kaposi's Sarcoma-Associated Herpesvirus Latency Protein LANA-1 and Host Protein KAP1 To Mediate Global Lytic Gene Repression. J Virol 2015; 89:7874-92. [PMID: 25995248 DOI: 10.1128/jvi.00895-15] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 05/13/2015] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease. We have previously shown that KSHV utilizes the host transcription factor Nrf2 to aid in infection of endothelial cells and oncogenesis. Here, we investigate the role of Nrf2 in PEL and PEL-derived cell lines and show that KSHV latency induces Nrf2 protein levels and transcriptional activity through the COX-2/PGE2/EP4/PKCζ axis. Next-generation sequencing of KSHV transcripts in the PEL-derived BCBL-1 cell line revealed that knockdown of this activated Nrf2 results in global elevation of lytic genes. Nrf2 inhibition by the chemical brusatol also induces lytic gene expression. Both Nrf2 knockdown and brusatol-mediated inhibition induced KSHV lytic reactivation in BCBL-1 cells. In a series of follow-up experiments, we characterized the mechanism of Nrf2-mediated regulation of KSHV lytic repression during latency. Biochemical assays showed that Nrf2 interacted with KSHV latency-associated nuclear antigen 1 (LANA-1) and the host transcriptional repressor KAP1, which together have been shown to repress lytic gene expression. Promoter studies showed that although Nrf2 alone induces the open reading frame 50 (ORF50) promoter, its association with LANA-1 and KAP1 abrogates this effect. Interestingly, LANA-1 is crucial for efficient KAP1/Nrf2 association, while Nrf2 is essential for LANA-1 and KAP1 recruitment to the ORF50 promoter and its repression. Overall, these results suggest that activated Nrf2, LANA-1, and KAP1 assemble on the ORF50 promoter in a temporal fashion. Initially, Nrf2 binds to and activates the ORF50 promoter during early de novo infection, an effect that is exploited during latency by LANA-1-mediated recruitment of the host transcriptional repressor KAP1 on Nrf2. Cell death assays further showed that Nrf2 and KAP1 knockdown induce significant cell death in PEL cell lines. Our studies suggest that Nrf2 modulation through available oral agents is a promising therapeutic approach in the treatment of KSHV-associated malignancies. IMPORTANCE KS and PEL are aggressive KSHV-associated malignancies with moderately effective, highly toxic chemotherapies. Other than ganciclovir and alpha interferon (IFN-α) prophylaxis, no KSHV-associated chemotherapy targets the underlying infection, a major oncogenic force. Hence, drugs that selectively target KSHV infection are necessary to eradicate the malignancy while sparing healthy cells. We recently showed that KSHV infection of endothelial cells activates the transcription factor Nrf2 to promote an environment conducive to infection and oncogenesis. Nrf2 is modulated through several well-tolerated oral agents and may be an important target in KSHV biology. Here, we investigate the role of Nrf2 in PEL and demonstrate that Nrf2 plays an important role in KSHV gene expression, lytic reactivation, and cell survival by interacting with the host transcriptional repressor KAP1 and the viral latency-associated protein LANA-1 to mediate global lytic gene repression and thus cell survival. Hence, targeting Nrf2 with available therapies is a viable approach in the treatment of KSHV malignancies.
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Habib E, Linher-Melville K, Lin HX, Singh G. Expression of xCT and activity of system xc(-) are regulated by NRF2 in human breast cancer cells in response to oxidative stress. Redox Biol 2015; 5:33-42. [PMID: 25827424 PMCID: PMC4392061 DOI: 10.1016/j.redox.2015.03.003] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 12/20/2022] Open
Abstract
Cancer cells adapt to high levels of oxidative stress in order to survive and proliferate by activating key transcription factors. One such master regulator, the redox sensitive transcription factor NF E2 Related Factor 2 (NRF2), controls the expression of cellular defense genes including those encoding intracellular redox-balancing proteins involved in glutathione (GSH) synthesis. Under basal conditions, Kelch-like ECH-associated protein 1 (KEAP1) targets NRF2 for ubiquitination. In response to oxidative stress, NRF2 dissociates from KEAP1, entering the nucleus and binding to the antioxidant response element (ARE) in the promoter of its target genes. Elevated reactive oxygen species (ROS) production may deplete GSH levels within cancer cells. System xc(-), an antiporter that exports glutamate while importing cystine to be converted into cysteine for GSH synthesis, is upregulated in cancer cells in response to oxidative stress. Here, we provided evidence that the expression of xCT, the light chain subunit of system xc(-), is regulated by NRF2 in representative human breast cancer cells. Hydrogen peroxide (H2O2) treatment increased nuclear translocation of NRF2, also increasing levels of xCT mRNA and protein and extracellular glutamate release. Overexpression of NRF2 up-regulated the activity of the xCT promoter, which contains a proximal ARE. In contrast, overexpression of KEAP1 repressed promoter activity and decreased xCT protein levels, while siRNA knockdown of KEAP1 up-regulated xCT protein levels and transporter activity. These results demonstrate the importance of the KEAP1/NRF2 pathway in balancing oxidative stress in breast cancer cells through system xc(-). We have previously shown that xCT is upregulated in various cancer cell lines under oxidative stress. In the current investigation, we focused on MCF-7 cells as a model for mechanistic studies.
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Affiliation(s)
- Eric Habib
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8
| | - Katja Linher-Melville
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8
| | - Han-Xin Lin
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8
| | - Gurmit Singh
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8S 4L8.
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