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Kulbe JR, Nguyen L, Le AA, Laird AE, Taffe MA, Nguyen JD, Fields JA. Nicotine, THC, and Dolutegravir Modulate E-Cigarette-Induced Changes in Addiction- and Inflammation-Associated Genes in Rat Brains and Astrocytes. Brain Sci 2023; 13:1556. [PMID: 38002516 PMCID: PMC10670019 DOI: 10.3390/brainsci13111556] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 10/30/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
E-cigarette use has been marketed as a safer alternative to traditional cigarettes, as a means of smoking cessation, and are used at a higher rate than the general population in people with HIV (PWH). Early growth receptor 2 (EGR2) and Activity-Regulated Cytoskeleton-Associated Protein (ARC) have a role in addiction, synaptic plasticity, inflammation, and neurodegeneration. This study showed that 10 days of exposure to e-cigarette vapor altered gene expression in the brains of 6-month-old, male, Sprague Dawley rats. Specifically, the e-cigarette solvent vapor propylene glycol (PG) downregulated EGR2 and ARC mRNA expression in frontal cortex, an effect which was reversed by nicotine (NIC) and THC, suggesting that PG could have a protective role against NIC and cannabis dependence. However, in vitro, PG upregulated EGR2 and ARC mRNA expression at 18 h in cultured C6 rat astrocytes suggesting that PG may have neuroinflammatory effects. PG-induced upregulation of EGR2 and ARC mRNA was reversed by NIC but not THC. The HIV antiretroviral DTG reversed the effect NIC had on decreasing PG-induced upregulation of EGR2, which is concerning because EGR2 has been implicated in HIV latency reversal, T-cell apoptosis, and neuroinflammation, a process that underlies the development of HIV-associated neurocognitive disorders.
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Affiliation(s)
- Jacqueline Renee Kulbe
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; (J.R.K.); (L.N.); (A.A.L.); (A.E.L.); (M.A.T.)
| | - Lauren Nguyen
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; (J.R.K.); (L.N.); (A.A.L.); (A.E.L.); (M.A.T.)
| | - Alexandra Anh Le
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; (J.R.K.); (L.N.); (A.A.L.); (A.E.L.); (M.A.T.)
| | - Anna Elizabeth Laird
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; (J.R.K.); (L.N.); (A.A.L.); (A.E.L.); (M.A.T.)
| | - Michael A. Taffe
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; (J.R.K.); (L.N.); (A.A.L.); (A.E.L.); (M.A.T.)
| | - Jacques D. Nguyen
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76706, USA;
| | - Jerel Adam Fields
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; (J.R.K.); (L.N.); (A.A.L.); (A.E.L.); (M.A.T.)
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2
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Liu B, Li G, Yang J, Li X, Wang H, Yang J, Wen H, He F. The mechanism of immune related signal pathway Egr2-FasL-Fas in transcription regulation and methylated modification of Paralichthys olivaceus under acute hypoxia stress. FISH & SHELLFISH IMMUNOLOGY 2022; 123:152-163. [PMID: 35219829 DOI: 10.1016/j.fsi.2022.02.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/04/2022] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
Apoptosis genes Egr2, Fas and FasL are related to immune responses. However, the mechanism of these genes inducing apoptosis in fish are still not very clear. An acute hypoxia treatment (1.73 ± 0.06 mg/L) for 24 h was carried out on Japanese flounder (Paralichthys olivaceus). The increasingly dense apoptotic signals at 3 h, 6 h, 12 h by TUNEL in skeletal muscle indicated that hypoxia could quickly affect muscle growth and development. Furthermore, we concluded that the Egr2-FasL-Fas signal pathway, which was located at the upstream of apoptotic executor protein caspases, was related to the apoptosis by quantitative real-time PCR, protein concentration detection in ELISA and double gene in situ hybridization methods. The mechanism of the pathway was researched in transcription regulation and epigenetic modification by dual-luciferase reporter assay and bisulfite modified method, respectively. Egr2, as a transcription factor, could up-regulate the expression of FasL gene. And its binding site was mainly between -479 to -1 of FasL gene promoter. The 5th CpG dinucleotides (-514) methylation levels in FasL gene were significantly affected by hypoxia, and they were negatively correlated with its expressions. These suggested that the -514 site may be a very important site to regulate the FasL gene expression. Above results, we concluded that hypoxia activated the immune related signal pathway Egr2-FasL-Fas to induced skeletal muscle apoptosis to affect growth and development of Japanese flounder. The study revealed the mechanism of hypoxia induced apoptosis, which could provide a reference for fish immunity and aquaculture management.
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Affiliation(s)
- Binghua Liu
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Guangling Li
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Jun Yang
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Xiaohui Li
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Hao Wang
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Jing Yang
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Haishen Wen
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China.
| | - Feng He
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China.
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3
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Li S, Guo W, Wu H. The role of post-translational modifications in the regulation of MCL1. Cell Signal 2021; 81:109933. [PMID: 33508399 DOI: 10.1016/j.cellsig.2021.109933] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 12/25/2022]
Abstract
Apoptosis is an evolutionarily conserved form of programed cell death (PCD) that has a vital effect on early embryonic development, tissue homeostasis and clearance of damaged cells. Dysregulation of apoptosis can lead to many diseases, such as Alzheimer's disease, cancer, AIDS and heart disease. The anti-apoptotic protein MCL1, a member of the BCL2 family, plays important roles in these physiological and pathological processes. Its high expression is closely related to drug resistances in the treatment of tumor. This review summarizes the structure and function of MCL1, the types of post-translational modifications of MCL1 and their effects on the functions of MCL1, as well as the treatment strategies targeting MCL1 in cancer therapy. The research on the fine regulation of MCL1 will be favorable to the provision of a promising future for the design and screening of MCL1 inhibitors.
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Affiliation(s)
- Shujing Li
- School of Bioengineering & Province Key Laboratory of Protein Modification and Disease, Liaoning Province, Dalian University of Technology, China
| | - Wanping Guo
- School of Bioengineering & Province Key Laboratory of Protein Modification and Disease, Liaoning Province, Dalian University of Technology, China
| | - Huijian Wu
- School of Bioengineering & Province Key Laboratory of Protein Modification and Disease, Liaoning Province, Dalian University of Technology, China.
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4
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Negash M, Tsegaye A, Wassie L, Howe R. Phenotypic and functional heterogeneity of peripheral γδ T cells in pulmonary TB and HIV patients in Addis Ababa, Ethiopia. BMC Infect Dis 2018; 18:464. [PMID: 30219039 PMCID: PMC6139120 DOI: 10.1186/s12879-018-3361-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 08/24/2018] [Indexed: 11/10/2022] Open
Abstract
Background Previous studies reported HIV infection alters the distribution and function of γδ T cells and their subsets. γδ T phenotypes in healthy and diseased individuals has received little attention in Ethiopia. We conducted this study to analyze the distribution of γδ T cells, the subsets and levels of expression of activation (CD38), exhaustion or anergy (CD95, PD1), adhesion (N-CAM/CD56 and CD103), among HIV and TB infected patients. Method The distributions of total γδ T cells, Vδ1 and Vδ2 T cells subsets were analyzed in clinical samples collected from asymptomatic HIV, pulmonary TB patients and apparently healthy controls. Multicolor flow cytometry and IFN-γ ELISA were used to assess surface markers and functional responses of Vδ2 T cells to isopentenyl pyrophosphate stimulation, respectively. Result A total of 52 study participants were enrolled in this study, 22 HIV + TB-, 10 HIV-TB+ and 20 healthy controls. No significant differences were observed in the distribution of total γδ T cells and in the proportion of Vδ1 subsets in all study groups, though slightly higher proportions were observed in HIV + TB- patients for the latter, of borderline statistical significance (p = 0.07). However, the proportion of Vδ2 T cells, as well as the IFN-γ response to IPP stimulation, was significantly reduced in HIV + TB- patients compared to healthy controls (p < 0.002). Expression of the activation marker CD38 (p < 0.001) and adhesion marker CD103 (αEβ7) were significantly higher in the Vδ1 T cell subset among both HIV + TB- (p = 0.013) and HIV-TB+ (p = 0.006) patients compared to healthy controls. Similarly, exhaustion markers, CD95 and PD1, were significantly higher in these two T cell subsets among both HIV + TB- and HIV-TB+ patients (p < 0.01). Interestingly, we also observed an increased proportion of effector memory (CD45RA-CD27-) and effector cytotoxic (CD45RA + CD27-) Vδ2 T cell subsets in HIV negative pulmonary TB patients. Conclusion In sum, HIV infection was associated with an increase in Vδ1 and a decrease in the function and frequencies of Vδ2 T cells. Moreover, increased effector Vδ2 T cells were observed among HIV negative pulmonary TB patients suggesting a potential role of these T cells in the host response to TB.
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Affiliation(s)
- Mikias Negash
- College of Health Sciences, Department of Medical Laboratory Science, Addis Ababa University, Addis Ababa, Ethiopia. .,Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
| | - Aster Tsegaye
- College of Health Sciences, Department of Medical Laboratory Science, Addis Ababa University, Addis Ababa, Ethiopia
| | - Liya Wassie
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Rawleigh Howe
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
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5
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He DD, Lu Y, Gittelman R, Jin Y, Ling F, Joshua A. Positive selection of the TRIM family regulatory region in primate genomes. Proc Biol Sci 2017; 283:rspb.2016.1602. [PMID: 27733547 DOI: 10.1098/rspb.2016.1602] [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: 07/17/2016] [Accepted: 09/13/2016] [Indexed: 12/13/2022] Open
Abstract
Viral selection pressure has acted on restriction factors that play an important role in the innate immune system by inhibiting the replication of viruses during primate evolution. Tripartite motif-containing (TRIM) family members are some of these restriction factors. It is becoming increasingly clear that gene expression differences, rather than protein-coding regions changes, could play a vital role in the anti-retroviral immune mechanism. Increasingly, recent studies have created genome-scale catalogues of DNase I hypersensitive sites (DHSs), which demark potentially functional regulatory DNA. To improve our understanding of the molecular evolution mechanism of antiviral differences between species, we leveraged 14 130 DHSs derived from 145 cell types to characterize the regulatory landscape of the TRIM region. Subsequently, we compared the alignments of the DHSs across six primates and found 375 DHSs that are conserved in non-human primates but exhibit significantly accelerated rates of evolution in the human lineage (haDHSs). Furthermore, we discovered 31 human-specific potential transcription factor motifs within haDHSs, including the KROX and SP1, that both interact with HIV-1 Importantly, the corresponding haDHS was correlated with antiviral factor TRIM23 Thus, our results suggested that some viruses may contribute, through regulatory DNA differences, to organismal evolution by mediating TRIM gene expression to escape immune surveillance.
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Affiliation(s)
- Dan-Dan He
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, People's Republic of China
| | - Yueer Lu
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, People's Republic of China
| | - Rachel Gittelman
- Department of Genome Sciences, University of Washington, Seattle, WA 98125, USA
| | - Yabin Jin
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, People's Republic of China
| | - Fei Ling
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, People's Republic of China
| | - Akey Joshua
- Department of Genome Sciences, University of Washington, Seattle, WA 98125, USA
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6
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Musinova YR, Sheval EV, Dib C, Germini D, Vassetzky YS. Functional roles of HIV-1 Tat protein in the nucleus. Cell Mol Life Sci 2016; 73:589-601. [PMID: 26507246 PMCID: PMC11108392 DOI: 10.1007/s00018-015-2077-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/01/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023]
Abstract
Human immunodeficiency virus-1 (HIV-1) Tat protein is one of the most important regulatory proteins for viral gene expression in the host cell and can modulate different cellular processes. In addition, Tat is secreted by the infected cell and can be internalized by neighboring cells; therefore, it affects both infected and uninfected cells. Tat can modulate cellular processes by interacting with different cellular structures and signaling pathways. In the nucleus, Tat might be localized either in the nucleoplasm or the nucleolus depending on its concentration. Here we review the distinct functions of Tat in the nucleoplasm and the nucleolus in connection with viral infection and HIV-induced oncogenesis.
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Affiliation(s)
- Yana R Musinova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
| | - Eugene V Sheval
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
| | - Carla Dib
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France
| | - Diego Germini
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France
| | - Yegor S Vassetzky
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia.
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France.
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France.
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7
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Wang J, Zhao Y, Gu K, Yu P, Zhang B, Wang W, Yang J, Xu Y. The novel porcine gene early growth response 4 (Egr4) is differentially expressed in the ovaries of Erhualian and Pietrain pigs. Reprod Fertil Dev 2014; 26:587-98. [PMID: 23719176 DOI: 10.1071/rd12380] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 03/28/2013] [Indexed: 01/09/2023] Open
Abstract
The early growth response 4 (Egr4) gene plays a critical role in human and mouse fertility. In the present study, Affymetrix microarray gene chips were used to evaluate differential gene expression in the ovaries between Erhualian and Pietrain pigs. In all, 487 and 573 transcripts were identified with significantly higher and lower expression, respectively, in Erhualian compared with Pietrain sows. The Egr4 gene, one of the differentially expressed genes, was cloned and its genomic structure was analysed. Egr4 expression is increased 120-fold in ovaries from Erhualian sows. The full-length cDNA of porcine Egr4 was obtained by in silico cloning and 5' rapid amplification of cDNA ends. The gene consists of two exons and its predicted protein contains a Cys2His2 zinc finger structure. The porcine transcript is alternatively spliced by exon sequence deletion, producing two different mRNAs differing at the 5' end of Exon 2. Egr4 transcripts were detected in the central nervous system, including the cerebrum, cerebellum, hypothalamus and pituitary gland, and were highly expressed in the ovary. The Egr4 gene was evaluated as a candidate gene for porcine reproductivity. To investigate the role of Egr4 in the ovary, Egr4 was knocked down using short interference (si) RNA in porcine granulosa cells. Knockdown of Egr4 using siRNA effectively inhibited Egr4 mRNA and protein expression and knockdown significantly affected the expression of Bax, P450arom, P450scc, Egr1, Egr2, and Egr3. In conclusion, these observations establish an important role for Egr4 in the porcine ovary.
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Affiliation(s)
- Jingjing Wang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yongyan Zhao
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Kecui Gu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Ping Yu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Baole Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Wei Wang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Juanjuan Yang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yinxue Xu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
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8
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Bouwman RD, Palser A, Parry CM, Coulter E, Rasaiyaah J, Kellam P, Jenner RG. Human immunodeficiency virus Tat associates with a specific set of cellular RNAs. Retrovirology 2014; 11:53. [PMID: 24990269 PMCID: PMC4086691 DOI: 10.1186/1742-4690-11-53] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 06/18/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Human Immunodeficiency Virus 1 (HIV-1) exhibits a wide range of interactions with the host cell but whether viral proteins interact with cellular RNA is not clear. A candidate interacting factor is the trans-activator of transcription (Tat) protein. Tat is required for expression of virus genes but activates transcription through an unusual mechanism; binding to an RNA stem-loop, the transactivation response element (TAR), with the host elongation factor P-TEFb. HIV-1 Tat has also been shown to alter the expression of host genes during infection, contributing to viral pathogenesis but, whether Tat also interacts with cellular RNAs is unknown. RESULTS Using RNA immunoprecipitation coupled with microarray analysis, we have discovered that HIV-1 Tat is associated with a specific set of human mRNAs in T cells. mRNAs bound by Tat share a stem-loop structural element and encode proteins with common biological roles. In contrast, we do not find evidence that Tat associates with microRNAs or the RNA-induced silencing complex (RISC). The interaction of Tat with cellular RNA requires an intact RNA binding domain and Tat RNA binding is linked to an increase in RNA abundance in cell lines and during infection of primary CD4+ T cells by HIV. CONCLUSIONS We conclude that Tat interacts with a specific set of human mRNAs in T cells, many of which show changes in abundance in response to Tat and HIV infection. This work uncovers a previously unrecognised interaction between HIV and its host that may contribute to viral alteration of the host cellular environment.
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Affiliation(s)
| | | | | | | | | | | | - Richard G Jenner
- MRC Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London WC1E 6BT, UK.
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9
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The HECT-type E3 ubiquitin ligase AIP2 inhibits activation-induced T-cell death by catalyzing EGR2 ubiquitination. Mol Cell Biol 2009; 29:5348-56. [PMID: 19651900 DOI: 10.1128/mcb.00407-09] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
E3 ubiquitin ligases, which target specific molecules for proteolytic destruction, have emerged as key regulators of immune functions. Several E3 ubiquitin ligases, including c-Cbl, Cbl-b, GRAIL, Itch, and Nedd4, have been shown to negatively regulate T-cell activation. Here, we report that the HECT-type E3 ligase AIP2 positively regulates T-cell activation. Ectopic expression of AIP2 in mouse primary T cells enhances their proliferation and interleukin-2 production by suppressing the apoptosis of T cells. AIP2 interacts with and promotes ubiquitin-mediated degradation of EGR2, a zinc finger transcription factor that has been found to regulate Fas ligand (FasL) expression during activation-induced T-cell death. Suppression of AIP2 expression by small RNA interference upregulates EGR2, inhibits EGR2 ubiquitination and FasL expression, and enhances the apoptosis of T cells. Therefore, AIP2 regulates activation-induced T-cell death by suppressing EGR2-mediated FasL expression via the ubiquitin pathway.
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10
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Jack J, Păun A, Rodríguez-Patón A. Effects of HIV-1 Proteins on the Fas-Mediated Apoptotic Signaling Cascade: A Computational Study of Latent CD4+ T Cell Activation. MEMBRANE COMPUTING 2009. [DOI: 10.1007/978-3-540-95885-7_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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11
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Darbinian N, Darbinyan A, Czernik M, Peruzzi F, Khalili K, Reiss K, Gordon J, Amini S. HIV-1 Tat inhibits NGF-induced Egr-1 transcriptional activity and consequent p35 expression in neural cells. J Cell Physiol 2008; 216:128-34. [PMID: 18247371 DOI: 10.1002/jcp.21382] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Infection with HIV-1 causes degeneration of neurons leading to motor and cognitive dysfunction in AIDS patients. One of the key viral regulatory proteins, Tat, which is released by infected cells, can be taken up by various uninfected cells including neurons and by dysregulating several biological events induces cell injury and death. In earlier studies, we demonstrated that treatment of neuronal cells with Tat affects the nerve growth factor (NGF) signaling pathway involving MAPK/ERK. Here we demonstrate that a decrease in the level of Egr-1, one of the targets for MAPK, by Tat has a negative impact on the level of p35 expression in NGF-treated neural cells. Further, we demonstrate a reduced level of Egr-1 association with the p35 promoter sequence in NGF-treated cells expressing Tat. As p35, by associating with Cdk5, phosphorylates several neuronal proteins including neurofilaments and plays a role in neuronal differentiation and survival, we examined kinase activity of p35 complexes obtained from cells expressing Tat. Results from H1 kinase assays showed reduced activity of the p35 complex from Tat-expressing cells in comparison to that from control cells. Accordingly, the level of phosphorylated neurofilaments was diminished in Tat-expressing cells. Similarly, treatment of PC12 cells with Tat protein or supernatant from HIV-1 infected cells decreased kinase activity of p35 in these cells. These observations ascribe a role for Tat in altering p35 expression and its activity that affects phosphorylation of proteins involved in neuronal cell survival.
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Affiliation(s)
- Nune Darbinian
- Department of Neuroscience, Temple University School of Medicine, Philadelphia, Pennsylvania
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12
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Cummings JS, Cairo C, Armstrong C, Davis CE, Pauza CD. Impacts of HIV infection on Vgamma2Vdelta2 T cell phenotype and function: a mechanism for reduced tumor immunity in AIDS. J Leukoc Biol 2008; 84:371-9. [PMID: 18495780 DOI: 10.1189/jlb.1207847] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
HIV infection causes rapid and lasting defects in the population of Vgamma2Vdelta2 T cells. To fully describe the impact of HIV, we examined PBMC samples from HIV+ patients receiving highly active antiretroviral therapy, who had displayed prolonged viral control and CD4 counts above 300 cells/mm3. We observed lower frequencies of CD27-/CD45RA- Vgamma2Vdelta2 cells in HIV+ individuals when compared with controls, coupled with an increased proportion of CD45RA+ cells. These changes were common among 24 HIV+ patients and were not related to CD4 cell count or viral RNA burden. Vgamma2 cells from HIV+ individuals had lower expression of Granzyme B and displayed reduced cytotoxicity against Daudi targets after in vitro stimulation. There was increased expression of FasR (CD95) on Vgamma2 cells from HIV+ PBMC that may be a mechanism for depletion of Vgamma2 cells during disease. In addition to the well-characterized defects in the Vgamma2 repertoire and functional responses to phosphoantigen, the proportion of CD27-/CD45RA- Vgamma2Vdelta2 T cells after isopentenyl pyrophosphate stimulation was reduced sharply in HIV+ donors versus controls. Thus, HIV infection has multiple impacts on the circulating Vgamma2Vdelta2 T cell population that combine to reduce the potential effector activity in terms of tumor cytotoxicity. Changes in Vgamma2Vdelta2 T cells, along with concomitant effects on NK and NKT cells that also contribute to tumor surveillance, may be important factors for elevating the risk of malignancy during AIDS.
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Affiliation(s)
- Jean-Saville Cummings
- Institute of Human Virology, University of Maryland School of Medicine, 725 W. Lombard St., N546, Baltimore, MD 21201, USA
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13
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Attenuated disease in SIV-infected macaques treated with a monoclonal antibody against FasL. Clin Dev Immunol 2008; 2007:93462. [PMID: 18317535 PMCID: PMC2248700 DOI: 10.1155/2007/93462] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 10/31/2007] [Indexed: 11/18/2022]
Abstract
Acute SIVmac infection in macaques is accompanied by high levels of plasma viremia that decline with the appearance of viral immunity and is a model for acute HIV disease in man. Despite specific immune responses, the virus establishes a chronic, persistent infection. The destruction of CD4+
and CD4- lymphocyte subsets in macaques
contributes to viral persistence and suggests the
importance of mechanisms for depleting both infected
and uninfected (bystander) cells. Bystander cell killing
can occur when FasL binds the Fas receptor on activated lymphocytes,
which include T and B cell subpopulations that are responding to the
infection. Destruction of specific immune cells could be an important
mechanism for blunting viral immunity and establishing persistent infection
with chronic disease. We inhibited the Fas pathway in vivo with a monoclonal
antibody against FasL (RNOK203). Here we show that treatment with anti-FasL
reduced cell death in circulating T and B cells, increased CTL and antibody
responses to viral proteins, and lowered the setpoint viremia. By blocking
FasL during only the first few weeks after infection, we attenuated SIVmac
disease and increased the life span for infected and treated macaques.
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14
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Iannello A, Debbeche O, Samarani S, Ahmad A. Antiviral NK cell responses in HIV infection: II. viral strategies for evasion and lessons for immunotherapy and vaccination. J Leukoc Biol 2008; 84:27-49. [PMID: 18388299 DOI: 10.1189/jlb.0907649] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
As is the case in other viral infections, humans respond to HIV infection by activating their NK cells. However, the virus uses several strategies to neutralize and evade the host's NK cell responses. Consequently, it is not surprising that NK cell functions become compromised in HIV-infected individuals in early stages of the infection. The compromised NK cell functions also adversely affect several aspects of the host's antiviral adaptive immune responses. Researchers have made significant progress in understanding how HIV counters NK cell responses of the host. This knowledge has opened new avenues for immunotherapy and vaccination against this infection. In the first part of this review article, we gave an overview of our current knowledge of NK cell biology and discussed how the genes encoding NK cell receptors and their ligands determine innate genetic resistance/susceptibilty of humans against HIV infections and AIDS. In this second part, we discuss NK cell responses, viral strategies to counter these responses, and finally, their implications for anti-HIV immunotherapy and vaccination.
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Affiliation(s)
- Alexandre Iannello
- Laboratory of Innate Immunity, Center of Research Ste Justine Hospital, 3175 Côte Ste-Catherine, Montreal, Qc, H3T 1C5, Canada
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15
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Sung TL, Rice AP. Effects of prostratin on Cyclin T1/P-TEFb function and the gene expression profile in primary resting CD4+ T cells. Retrovirology 2006; 3:66. [PMID: 17014716 PMCID: PMC1599745 DOI: 10.1186/1742-4690-3-66] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 10/02/2006] [Indexed: 12/11/2022] Open
Abstract
Background The latent reservoir of human immunodeficiency virus type 1 (HIV-1) in resting CD4+ T cells is a major obstacle to the clearance of infection by highly active antiretroviral therapy (HAART). Recent studies have focused on searches for adjuvant therapies to activate this reservoir under conditions of HAART. Prostratin, a non tumor-promoting phorbol ester, is a candidate for such a strategy. Prostratin has been shown to reactivate latent HIV-1 and Tat-mediated transactivation may play an important role in this process. We examined resting CD4+ T cells from healthy donors to determine if prostratin induces Cyclin T1/P-TEFb, a cellular kinase composed of Cyclin T1 and Cyclin-dependent kinase-9 (CDK9) that mediates Tat function. We also examined effects of prostratin on Cyclin T2a, an alternative regulatory subunit for CDK9, and 7SK snRNA and the HEXIM1 protein, two factors that associate with P-TEFb and repress its kinase activity. Results Prostratin up-regulated Cyclin T1 protein expression, modestly induced CDK9 protein expression, and did not affect Cyclin T2a protein expression. Although the kinase activity of CDK9 in vitro was up-regulated by prostratin, we observed a large increase in the association of 7SK snRNA and the HEXIM1 protein with CDK9. Using HIV-1 reporter viruses with and without a functional Tat protein, we found that prostratin stimulation of HIV-1 gene expression appears to require a functional Tat protein. Microarray analyses were performed and several genes related to HIV biology, including APOBEC3B, DEFA1, and S100 calcium-binding protein genes, were found to be regulated by prostratin. Conclusion Prostratin induces Cyclin T1 expression and P-TEFb function and this is likely to be involved in prostratin reactivation of latent HIV-1 proviruses. The large increase in association of 7SK and HEXIM1 with P-TEFb following prostratin treatment may reflect a requirement in CD4+ T cells for a precise balance between active and catalytically inactive P-TEFb. Additionally, genes regulated by prostratin were identified that have the potential to regulate HIV-1 replication both positively and negatively.
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Affiliation(s)
- Tzu-Ling Sung
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Andrew P Rice
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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16
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Silva P, Soares J, Brasil B, Nogueira S, Andrade A, de Magalhães J, Bonjardim M, Ferreira P, Kroon E, Bruna-Romero O, Bonjardim C. Differential role played by the MEK/ERK/EGR-1 pathway in orthopoxviruses vaccinia and cowpox biology. Biochem J 2006; 398:83-95. [PMID: 16686604 PMCID: PMC1525012 DOI: 10.1042/bj20060509] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Appropriation of signalling pathways facilitates poxvirus replication. Poxviruses, as do most viruses, try to modify the host cell environment to achieve favourable replication conditions. In the present study, we show that the early growth response 1 gene (egr-1) is one of the host cell factors intensely modulated by the orthopoxviruses VV (vaccinia virus) and CPV (cowpox virus). These viruses stimulated the generation of both egr-1 mRNA and its gene product, throughout their entire replication cycles, via the requirement of MEK [mitogen-activated protein kinase/ERK (extracellular-signal-regulated kinase) kinase]/ERK pathway. We showed that, upon VV infection, EGR-1 translocates into the nucleus where it binds to the EBS (egr-1-binding site) positioned at the 5' region of EGR-1-regulated genes. In spite of both viruses belonging to the same genus, several lines of evidence, however, revealed a remarkable contrast between them as far as the roles played by the MEK/ERK/EGR-1 pathway in their biological cycles are concerned. Hence (i) the knocking-down of egr-1 by siRNA (small interfering RNA) proved that this transcription factor is of critical relevance for VV biology, since a decrease of about one log cycle in virus yield was verified, along with a small virus plaque phenotype, whereas the gene silencing did not have a detrimental effect on either CPV multiplication or viral plaque size; (ii) while both pharmacological and genetic inhibition of MEK/ERK resulted in a significant decrease in VV yield, both approaches had no impact on CPV multiplication; and (iii) CPV DNA replication was unaffected by pharmacological inhibition of MEK/ERK, but phosphorylation of MEK/ERK was dependent on CPV DNA replication, contrasting with a significant VV DNA inhibition and VV DNA replication-independence to maintain ERK1/2 phosphorylation, observed under the same conditions.
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Affiliation(s)
- Patrícia N. G. Silva
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Jamária A. P. Soares
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Bruno S. A. F. Brasil
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Sarah V. Nogueira
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Anderson A. Andrade
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - José C. de Magalhães
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Marisa B. Bonjardim
- ‡Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Paulo C. P. Ferreira
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Erna G. Kroon
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Oscar Bruna-Romero
- §Laboratório de Agentes Recombinantes, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Cláudio A. Bonjardim
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- To whom correspondence should be addressed (email )
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Hidalgo-Estévez AM, González E, Punzón C, Fresno M. Human immunodeficiency virus type 1 Tat increases cooperation between AP-1 and NFAT transcription factors in T cells. J Gen Virol 2006; 87:1603-1612. [PMID: 16690925 DOI: 10.1099/vir.0.81637-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat affects cellular gene expression through modulation of the activity of different transcription factors. Here, the role of Tat in the cooperation between nuclear factor of activated T cells (NFAT) and activator protein 1 (AP-1) transcription factors was investigated. Constitutive or transient Tat expression in Jurkat T cells enhanced cooperative NFAT/AP-1- but not AP-1-dependent transcription independent of its ability to transactivate the HIV-1 LTR. The enhancing effect of Tat took place after nuclear translocation of NFAT. Furthermore, transactivation of an NFAT/AP-1 reporter by transfection of NFAT and c-Jun was strongly enhanced by simultaneous Tat transfection. Moreover, intracellular Tat expression increased the binding of NFAT/AP-1 complexes to the interleukin 2 promoter without significantly altering NFAT- and AP-1-independent binding. HIV-1 Tat interacted with NFAT but not c-Jun. These results indicate that Tat interacts with NFAT, affecting its cooperation with AP-1, without altering independent binding of these transcription factors to DNA.
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Affiliation(s)
- Alicia M Hidalgo-Estévez
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Esther González
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Carmen Punzón
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Manuel Fresno
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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18
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Imam SZ, Jankovic J, Ali SF, Skinner JT, Xie W, Conneely OM, Le WD. Nitric oxide mediates increased susceptibility to dopaminergic damage in Nurr1 heterozygous mice. FASEB J 2006; 19:1441-50. [PMID: 16126911 DOI: 10.1096/fj.04-3362com] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Knocking out of Nurr1 gene, a member of nuclear receptor superfamily, causes selective agenesis of dopaminergic neurons in midbrain. Reduced expression of Nurr1 increases the vulnerability of mesencephalic dopamine neurons to dopaminergic toxins. We evaluated the role of nitric oxide as a possible mechanism for this increased susceptibility. Increased expression of neuronal nitric oxide synthase and increased 3-nitrotyrosine were observed in striatum of Nurr1 heterozygous (Nurr1 +/-) mice as compared with wild-type. Increased cytochrome C activation and consecutive release of Smac/DIABLO were also observed in Nurr1 +/- mice. An induction of active Caspase-3 and p53, cleavage of poly-ADP (RNase) polymerase and reduced expression of bcl-2 were observed in Nurr1 +/- mice. Methamphetamine significantly increased these markers in Nurr1 +/- mice as compared with wild-type. The present data therefore suggest that nitric oxide plays a role as a modulating factor for the increased susceptibility, but not the potentiation, of the dopaminergic terminals in Nurr1 +/- mice. We also report that this increased neuronal nitric oxide synthase expression and increased nitration in Nurr1 +/- mice led to the activation of apoptotic cascade via the differential alterations in the DNA binding activity of transcription factors responsible for the propagation of growth arrest as well as apoptosis.
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Affiliation(s)
- Syed Z Imam
- South Texas Veteran Health Care System and Department of Medicine of UT Health Science, San Antonio, Texas, USA.
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19
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Acheampong EA, Parveen Z, Muthoga LW, Wasmuth-Peroud V, Kalayeh M, Bashir A, Diecidue R, Mukhtar M, Pomerantz RJ. Molecular interactions of human immunodeficiency virus type 1 with primary human oral keratinocytes. J Virol 2005; 79:8440-53. [PMID: 15956588 PMCID: PMC1143773 DOI: 10.1128/jvi.79.13.8440-8453.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection of the oral mucosa of human immunodeficiency virus type 1 (HIV-1)-infected individuals remains an under-evaluated and somewhat enigmatic process. Nonetheless, it is of profound importance in the ongoing AIDS pandemic, based on its potential as a site of person-to-person transmission of the virus as well as a location of HIV-1 pathogenesis and potential reservoir of disease in the setting of virally suppressive highly active antiretroviral therapy. We utilized molecular and virological techniques to analyze HIV-1 infection of primary human mucosal cells and also evaluated the proapoptotic potential of selected HIV-1 proteins in primary isolated human oral keratinocytes. Primary isolated human oral keratinocytes were plated on 0.4 microM polyethylenetetraphthalate cell culture inserts to form an in vitro oral mucosal layer. The strength of this layer in forming a barrier was determined by measuring trans-epithelial electrical current passage across the monolayer. The oral keratinocyte monolayers had trans-epithelial electrical resistance of approximately 176 to 208 omega. For viral infectivity assays, the macrophage-tropic (R5) HIV-1 strains, YU-2 and ADA, and T-cell-line-tropic (X4), NL4-3 virions, incubated with or without deoxynucleoside triphosphates (dNTPs) and/or the polyamines spermine and spermidine, were used to infect oral keratinocytes. Of importance, polyamines and dNTPs have been shown to enhance natural endogenous reverse transcription (NERT), a step essential for early lentiviral infection, and are abundantly present in human semen. The infectivities of HIV-1 strains YU-2, ADA, and NL4-3 for these primary keratinocytes were dramatically increased by the addition of physiological concentrations of dNTPs, spermine, and spermidine. Binding and viral internalization assay studies showed no differences in these oral mucosal cells, with or without NERT-altering agents. It was also observed that the recombinant, cell-free HIV-1 proteins Nef, Tat, and gp120 (R5) induced apoptosis in primary oral keratinocytes compared with the results seen with nontreated cells or cells treated with glutathione S-transferase protein as a control under similar conditions. Microarray analyses suggested that HIV-1 gp120 and Tat induce apoptosis in primary human oral keratinocytes via the Fas/FasL apoptotic pathway, whereas induction of apoptosis by Nef occurs through both Fas/FasL and mitochondrial apoptotic pathways. Thus, these findings suggest molecular mechanisms by which semen in particular, as well as other bodily fluids such as cervicovaginal secretions, could increase oral transmission of HIV-1 via increasing infectivity in confluent and low-replicating oral keratinocytes. As well, the induction of apoptosis in human oral keratinocytes with relevant HIV-1-specific proteins suggests another potential complementary mechanism by which the oral mucosa barrier may be disrupted during HIV-1 infection in vivo.
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Affiliation(s)
- Edward A Acheampong
- The Dorrance H. Hamilton Laboratories, Center for Human Virology and Biodefense, Division of Infectious Diseases and Environmental Medicine, Department of Medicine, Philadelphia, Pennsylvania 19107, USA
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20
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Wieland GD, Nehmann N, Müller D, Eibel H, Siebenlist U, Sühnel J, Zipfel PF, Skerka C. Early growth response proteins EGR-4 and EGR-3 interact with immune inflammatory mediators NF-κB p50 and p65. J Cell Sci 2005; 118:3203-12. [PMID: 16014385 DOI: 10.1242/jcs.02445] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here, we characterize the basis for the T-cell-specific activity of the human zinc-finger protein early growth response factor 4 (EGR-4). A yeast two-hybrid screen showed interaction of EGR-4 with NF-κB p50. Using recombinant proteins, stable physical complex formation was confirmed for EGR-4 and EGR-3 with p50 and with p65 using glutathione-S-transferase pull-down assays and surface-plasmon-resonance and peptide-spot analyses. In vivo interaction of EGR-4 and EGR-3 with NF-κB p65 was demonstrated by immunoprecipitation experiments and fluorescence-resonance-energy transfer (FRET) analysis showing interaction in the nucleus of transfected Jurkat T cells. In transfection assays, EGR-p50 complexes were transcriptionally inactive and EGR-p65 complexes strongly activated transcription of the promoters of the human genes encoding the cytokines interleukin 2, tissue necrosis factor α and ICAM-1. The EGR-p65 complexes increased reporter-gene activity about 100-fold and thus exceeded the transcriptional activities of the p65 homodimer and the p65/p50 heterodimers. The major interaction domain for p65 was localized within the third zinc finger of EGR-4 using deletion mutants for pull-down assays and peptide-spot assays. By computer modeling, this interaction domain was localized to an α-helical region and shown to have the central amino acids surface exposed and thus accessible for interaction. In summary, in T cells, the two zinc-finger proteins EGR-4 and EGR-3 interact with the specific nuclear mediator NF-κB and control transcription of genes encoding inflammatory cytokines.
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Affiliation(s)
- Gerhard D Wieland
- Department of Infection Biology, Leibniz-Institute for Natural Products, Research and Infection Biology, Hans-Knoell-Institute, Butenbergstrasse 11a, 07745 Jena, Germany
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21
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Gülow K, Kaminski M, Darvas K, Süss D, Li-Weber M, Krammer PH. HIV-1 Trans-Activator of Transcription Substitutes for Oxidative Signaling in Activation-Induced T Cell Death. THE JOURNAL OF IMMUNOLOGY 2005; 174:5249-60. [PMID: 15843521 DOI: 10.4049/jimmunol.174.9.5249] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Termination of an immune response requires elimination of activated T lymphocytes by activation-induced cell death (AICD). In AICD, CD95 (Apo-1/Fas) ligand (L) triggers apoptosis of CD95-positive activated T lymphocytes. In AIDS patients, AICD is strongly enhanced and accelerated. We and others have previously shown that HIV-1 trans-activator of transcription (HIV-1 Tat) sensitizes T cells toward CD95-mediated apoptosis and up-regulates CD95L expression by affecting the cellular redox balance. In this study, we show that it is hydrogen peroxide (H(2)O(2)) that functions as an essential second messenger in TCR signaling. The H(2)O(2) signal combined with simultaneous calcium (Ca(2+)) influx into the cytosol constitutes the minimal requirement for induction of CD95L expression. Either signal alone is insufficient. We further show that HIV-1 Tat interferes with TCR signaling and induces a H(2)O(2) signal. H(2)O(2) generated by HIV-1 Tat combines with CD4-dependent calcium influx and causes massive T cell apoptosis. Thus, our data provide an explanation for CD4(+) T lymphocyte depletion during progression of AIDS.
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Affiliation(s)
- Karsten Gülow
- Tumor Immunology Program, German Cancer Research Center, Heidelberg, Germany
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22
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Torgler R, Jakob S, Ontsouka E, Nachbur U, Mueller C, Green DR, Brunner T. Regulation of activation-induced Fas (CD95/Apo-1) ligand expression in T cells by the cyclin B1/Cdk1 complex. J Biol Chem 2004; 279:37334-42. [PMID: 15215233 DOI: 10.1074/jbc.m406913200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Fas (CD95/Apo-1) ligand-mediated apoptosis has been recognized as an important mechanism of cell-mediated cytotoxicity and maintenance of immune homeostasis. Chronically activated T cells undergo activation-induced cell death (AICD), which depends on simultaneous Fas and Fas ligand expression. Previous reports have suggested that AICD might be linked to cell cycle progression of T cells and therefore to the expression of cell cycle-related molecules. In particular, cyclin B1 has been implicated in the induction of AICD in T cells. In this study, we have investigated the role of cyclin B1 in AICD and the expression of effector molecules involved in this form of cell death. Our results show that inhibition of cyclin B1 blocks AICD in T cells through specific inhibition of Fas ligand expression but not Fas-induced apoptosis. This effect of cyclin B1 appears to be mediated through the cyclin B1/cyclin-dependent kinase 1 (Cdk1/Cdc2) complex because overexpression of cyclin B1 enhances FasL promoter activity, whereas a dominant-negative version of Cdk1 blocks Fas ligand promoter induction. We provide further evidence that cyclin B1/Cdk1 regulates FasL transcription through the regulation of NFkappaB activation because dominant-negative Cdk1 inhibits activation-induced NFkappaB reporter and Rel A-induced FasL promoter activity. In conclusion, our data support a link between cell cycle progression, activation-induced Fas ligand expression, and apoptosis in T cells.
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Affiliation(s)
- Ralph Torgler
- Division of Immunopathology, Institute of Pathology, University of Bern, 3010 Berne, Switzerland
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23
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Yoo YG, Lee MO. Hepatitis B virus X protein induces expression of Fas ligand gene through enhancing transcriptional activity of early growth response factor. J Biol Chem 2004; 279:36242-9. [PMID: 15173177 DOI: 10.1074/jbc.m401290200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
FasL expressed in tumor cells plays an important role in the escape from immune surveillance by inducing apoptosis in T-cells bearing Fas. Since the Fas/FasL signaling pathway requires transcriptional induction of the FasL gene, elucidation of the precise mechanisms underlying regulation of FasL gene expression may provide useful molecular insights on tumor progression. We and others (Shin, E. C., Shin, J. S., Park, J. H., Kim, H., and Kim, S. J. (1999) Int. J. Cancer 82, 587-591; Lee, M. O., Kang, H. J., Cho, H., Shin, E. C., Park, J. H., and Kim, S. J. (2001) Biochem. Biophys. Res. Commun. 288, 1162-1168) have previously reported that hepatitis B virus X protein (HBx) plays a role in the induction of FasL expression in hepatitis B virus-associated hepatoma. In the present study, we analyzed the potential cis- and trans-acting factors that regulate FasL promoter. We found that HBx induced activity of the reporter containing FasL promoter through binding site for Egr but not through NFAT or SP-1, which are known as strong activators of the FasL promoter in T-cells. Transient expression of antisense Egr-2 and antisense Egr-3 abolished expression of FasL, which further confirmed the role of Egr in the HBx-mediated FasL expression. Also we observed that HBx increased the transcriptional activity of Egr-2 and Egr-3 by enhancing expression as well as the transactivation function of these proteins. HBx interacted with Egr-2 and Egr-3 in vivo and enhanced binding of Egr to the co-activator, cAMP-response element-binding protein-binding protein, which may explain the molecular mechanism by which HBx induced the transactivation function of Egr. Finally, we found that the carboxyl terminus of HBx was necessary and sufficient for FasL induction as well as activation of Egr. Taken together, our results show a novel mechanism by which HBx induces FasL gene expression that is mediated by enhancing transcriptional activity of Egr-2 and Egr-3.
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Affiliation(s)
- Young-Gun Yoo
- Department of Bioscience and Biotechnology, Sejong University, Seoul 143-747, Korea
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24
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Régulier EG, Reiss K, Khalili K, Amini S, Zagury JF, Katsikis PD, Rappaport J. T-cell and neuronal apoptosis in HIV infection: implications for therapeutic intervention. Int Rev Immunol 2004; 23:25-59. [PMID: 14690854 DOI: 10.1080/08830180490265538] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The pathogenesis of HIV infection involves the selective loss of CD4+ T cells contributing to immune deficiency. Although loss of T cells leading to immune dysfunction in HIV infection is mediated in part by viral infection, there is a much larger effect on noninfected T cells undergoing apoptosis in response to activation stimuli. In the subset of patients with HIV dementia complex, neuronal injury, loss, and apoptosis are observed. Viral proteins, gp120 and Tat, exhibit proapoptotic activities when applied to T cell and neuronal cultures by direct and indirect mechanisms. The pathways leading to cell death involve the activation of one or more death receptor pathways (i.e., TNF-alpha, Fas, and TRAIL receptors), chemokine receptor signaling, cytokine dysregulation, caspase activation, calcium mobilization, and loss of mitochondrial membrane potential. In this review, the mechanisms involved in T-cell and neuronal apoptosis, as well as antiapoptotic pathways potentially amenable to therapeutic application, are discussed.
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Affiliation(s)
- Emmanuel G Régulier
- Center for Neurovirology and Cancer Biology, Temple University, Philadelphia, Pennsylvania 19122, USA
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25
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Abstract
CD95/CD95L mediated apoptosis is an important mechanism of immune homeostasis. It is instrumental for termination of an immune response and mainly be involved in peripheral tolerance. Dysregulation of the CD95/CD95L system leads to severe diseases. In this review, we present a survey of the role of the CD95/CD95L system in the immune system and, particularly, focus on the signals and transcription factors (NF-AT, Egr, NF-kappaB, AP-1, c-Myc, Nur77, IRFs, SP-1, ALG-4, ROR(gamma)t, and CIITA) involved in CD95L expression. It should also be evident from this review that a profound insight into the molecular mechanisms of CD95L activation should allow to explore potential therapeutic means to treat CD95/CD95L-dependent diseases.
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Affiliation(s)
- Min Li-Weber
- Tumor Immunology Program G0300, German Cancer Research Center (DKFZ), INF 280, D-69120 Heidelberg, Germany.
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26
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Abstract
Fas ligand (FasL) is a type II transmembrane protein that plays a critical role in immune homeostasis by binding to its receptor Fas (CD95) and inducing apoptosis. Fas/FasL dysregulation contributes to infectious disease pathogenesis. Microorganisms may inhibit Fas signal transduction to prolong intracellular survival and prevent killing by immune effector cells. FasL may be upregulated in directly infected cells to enhance killing of responding immune cells and facilitate immune evasion. The host response to infection may aim to induce apoptosis in directly infected cells, but immune cells that target directly infected cells can induce Fas-mediated apoptosis of uninfected bystander cells. FasL also contributes to the generation and regulation of the inflammatory response in infection. The multiple roles of FasL in infectious disease pathogenesis are discussed in the context of viral, bacterial and parasitic infections.
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Affiliation(s)
- D H Dockrell
- Division of Genomic Medicine, University of Sheffield, School of Medicine and Biomedical Sciences, Sheffield, UK.
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Gil J, Bermejo M, Alcamí J. HIV and apoptosis: a complex interaction between cell death and virus survival. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2004; 36:117-49. [PMID: 15171610 DOI: 10.1007/978-3-540-74264-7_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- J Gil
- Wolfson Institute for Biomedical Research, University College, London, UK
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Alimonti JB, Ball TB, Fowke KR. Mechanisms of CD4+ T lymphocyte cell death in human immunodeficiency virus infection and AIDS. J Gen Virol 2003; 84:1649-1661. [PMID: 12810858 DOI: 10.1099/vir.0.19110-0] [Citation(s) in RCA: 213] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIDS, caused by the retroviruses human immunodeficiency virus type 1 and type 2 (HIV-1 and HIV-2), has reached pandemic proportions. Therefore, it is critical to understand how HIV causes AIDS so that appropriate therapies can be formulated. Primarily, HIV infects and kills CD4(+) T lymphocytes, which function as regulators and amplifiers of the immune response. In the absence of effective anti-retroviral therapy, the hallmark decrease in CD4(+) T lymphocytes during AIDS results in a weakened immune system, impairing the body's ability to fight infections or certain cancers such that death eventually ensues. The major mechanism for CD4(+) T cell depletion is programmed cell death (apoptosis), which can be induced by HIV through multiple pathways. Death of HIV-infected cells can result from the propensity of infected lymphocytes to form short-lived syncytia or from an increased susceptibility of the cells to death. However, the apoptotic cells appear to be primarily uninfected bystander cells and are eradicated by two different mechanisms: either a Fas-mediated mechanism during activation-induced cell death (AICD), or as a result of HIV proteins (Tat, gp120, Nef, Vpu) released from infected cells stimulating apoptosis in uninfected bystander cells. There is also evidence that as AIDS progresses cytokine dysregulation occurs, and the overproduction of type-2 cytokines (IL-4, IL-10) increases susceptibility to AICD whereas type-1 cytokines (IL-12, IFN-gamma) may be protective. Clearly there are multiple causes of CD4(+) T lymphocyte apoptosis in AIDS and therapies that block or decrease that death could have significant clinical benefit.
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Affiliation(s)
- Judie B Alimonti
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, 539-730 William Avenue, Winnipeg, MB, Canada R3E 0W3
| | - T Blake Ball
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, 539-730 William Avenue, Winnipeg, MB, Canada R3E 0W3
| | - Keith R Fowke
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, 539-730 William Avenue, Winnipeg, MB, Canada R3E 0W3
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Badley AD, Roumier T, Lum JJ, Kroemer G. Mitochondrion-mediated apoptosis in HIV-1 infection. Trends Pharmacol Sci 2003; 24:298-305. [PMID: 12823956 DOI: 10.1016/s0165-6147(03)00125-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acquired immunodeficiency syndrome (AIDS), which is caused by human immunodeficiency virus (HIV-1), involves the apoptotic destruction of lymphocytes and, in the context of AIDS-associated pathologies, of neurons and myocytes. Several proteins encoded by HIV-1 trigger apoptosis by inducing permeabilization of the mitochondrial membrane. Several nucleoside analogs used clinically in the treatment of HIV-1 inhibit the replication of mitochondrial DNA (mtDNA) and/or increase the frequency of mtDNA mutations. These cause severe mitochondriopathy and might contribute to lipodystrophy, the complication associated with HIV-1 therapy. HIV-1 protease inhibitors can inhibit apoptosis at the mitochondrial level, which might help to alleviate lymphopenia. Thus, it appears that the pathogenesis of AIDS, and the pharmacological interventions and complications associated with this disease, affect the mitochondrial regulation of apoptosis, which, therefore, largely determines the outcome of HIV-1 infection.
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Affiliation(s)
- Andrew D Badley
- Division of Infectious Diseases, Mayo Clinic, Rochester MN 55905, USA.
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Gallagher PG, Bao Y, Serrano SMT, Kamiguti AS, Theakston RDG, Fox JW. Use of microarrays for investigating the subtoxic effects of snake venoms: insights into venom-induced apoptosis in human umbilical vein endothelial cells. Toxicon 2003; 41:429-40. [PMID: 12657312 DOI: 10.1016/s0041-0101(02)00359-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The pathological effects of only a small percentage of the total number of protein components of snake venoms are well documented, yet this knowledge has led to a general understanding of the physiological consequences of snake venom poisoning. The aim of this study was to assess the effect of subpathological levels of Crotalus atrox (Western diamondback rattlesnake) and Bothrops jararaca (Jararaca) snake venoms on the gene expression profile of human umbilical vein endothelial cells (HUVEC) in culture. Analysis of the data demonstrated that HUVECs treated with C. atrox venom had 33 genes up-regulated with significant fold changes of 1.5 or greater compared to untreated control cells. Ten genes were down-regulated with 1.5 or greater fold changes. In cells treated with B. jararaca venom, 33 genes were observed to be up-regulated and 11 genes were down-regulated with a fold change of 1.5 or more. More than half of the up-regulated genes and approximately half of the down-regulated genes detected in cells treated with the venoms were found in both data sets underscoring both the similarities and differences between the two venoms. Ontological categorization of the up-regulated genes from endothelial cells treated with either C. atrox or B. jararaca venom gave the cell growth/maintenance and signal transducer groups as having the most members. The ontology of the down-regulated genes from both venom-treated cell samples was more varied but interestingly, the predominant ontology class was also cell growth/maintenance. Many of the up-regulated genes are involved in the Fas ligand/TNF-alpha receptor apoptotic pathway. In summary, these experiments demonstrate the power of gene expression profiling to explore the subtoxic effects of venoms on gene expression and highlight its potential for the discovery of novel insights into a variety of biological processes and signal transduction pathways. Furthermore, these studies illustrate the subtle functional differences between similar venoms that are not always evident from standard analyses.
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Affiliation(s)
- Paul G Gallagher
- Health Sciences Center, Department of Microbiology, University of Virginia, Box 441, Jordan Hall, Charlottesville, VA 22908-0734, USA
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31
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Decker EL, Nehmann N, Kampen E, Eibel H, Zipfel PF, Skerka C. Early growth response proteins (EGR) and nuclear factors of activated T cells (NFAT) form heterodimers and regulate proinflammatory cytokine gene expression. Nucleic Acids Res 2003; 31:911-21. [PMID: 12560487 PMCID: PMC149206 DOI: 10.1093/nar/gkg186] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2002] [Revised: 12/10/2002] [Accepted: 12/10/2002] [Indexed: 02/02/2023] Open
Abstract
Activation of transcription factors by receptor mediated signaling is an essential step for T lymphocyte effector function. Following antigenic stimulation of T cells the two central cytokines IL-2 and TNFalpha are co-expressed and co-regulated. Two important transcription factors, i.e., early growth response (EGR) protein EGR-1 and nuclear factors of activated T cells (NFAT) protein NFATc, regulate transcription of the human IL-2 cytokine and the same combination of EGR and NFAT proteins seems relevant for coordinated cytokine expression. Here we demonstrate that the zinc finger protein EGR-1 and two members of the NFAT protein family bind simultaneously to adjacent elements position -168 to -150 within the TNFalpha promoter. Both promoter sites are important for TNFalpha gene transcription as shown by transfection assays having the IL-2 and TNFalpha promoters linked to a luciferase reporter. The use of promoter deletion constructs with the zinc finger protein (ZIP), the NFAT binding element or a combination of both deleted show a functional cooperation of these elements and of their binding factors. These experiments demonstrate that EGR-1 as well as EGR-4 functionally cooperate with NFAT proteins and induce expression of both cytokine genes. Using tagged NFATc and NFATp in glutathione S-transferase pull down assays showed interaction and physical complex formation of each NFAT protein with recombinant, as well as native, EGR-1 and EGR-4 proteins. Thus EGR-NFAT interaction and complex formation seems essential for human cytokine expression as adjacent ZIP and NFAT elements are conserved in the IL-2 and TNFalpha gene promoters. Binding of regulatory EGR and NFAT factors to these sites and the functional interaction and formation of stable heterodimeric complexes indicate an important role of these factors for gene transcription.
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Affiliation(s)
- Eva L Decker
- Research Group of Biomolecular Medicine, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Bernhard-Nocht Strasse 74, Germany
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Kavurma MM, Khachigian LM. Signaling and transcriptional control of Fas ligand gene expression. Cell Death Differ 2003; 10:36-44. [PMID: 12655294 DOI: 10.1038/sj.cdd.4401179] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Fas ligand (FasL), a member of the tumor necrosis factor family, initiates apoptosis by binding to its surface receptor Fas. As a consequence, there is sequential activation of caspases and the release of cytochrome c from the mitochondria, with additional caspase activation followed by cellular degradation and death. Recent studies have shed important insight into the molecular mechanisms controlling FasL gene expression at the level of transcription. Nuclear factors such as nuclear factor in activated T cells, nuclear factor-kappa B, specificity protein-1, early growth response factor, interferon regulatory factor, c-Myc and the forkhead transcriptional regulator, alone or cooperatively, activate FasL expression. These factors are often coexpressed with FasL in pathophysiologic settings including human atherosclerotic lesions. Here, we review these important advances in our understanding of the signaling and transcriptional mechanisms controlling FasL gene expression.
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Affiliation(s)
- M M Kavurma
- Centre for Thrombosis and Vascular Research, Department of Pathology, The University of New South Wales, Sydney, Australia
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Abstract
Due to the development of HIV-1 resistance to current antiviral drugs and the known toxicity of many of these drugs, there is a clear need to identify and develop novel compounds for use in the treatment of HIV-1 infected patients. The HIV-1 regulatory proteins, Tat and Rev, are required for HIV-1 replication and therefore represent two important viral targets for drug development. Novel drugs that target these proteins would increase the number of available treatment strategies for HIV-1 infection. This could result in better combination therapies in which many different viral targets could be inhibited simultaneously, thereby decreasing the likelihood of selecting for drug-resistant viruses. This review outlines many of the ways that Tat and Rev can be targeted for drug development, describes recently reported lead compounds as inhibitors of these proteins and discusses strategies for implementing drug screens for identifying novel inhibitors.
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Affiliation(s)
- Roger G Ptak
- Infectious Disease Research Department, Southern Research Institute, 431 Aviation Way, Frederick, Maryland 21701, USA.
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