1
|
Adolph RS, Beck E, Schweimer K, Di Fonzo A, Weyand M, Rösch P, Wöhrl BM, Steegborn C. Molecular Mechanism of Sirtuin 1 Inhibition by Human Immunodeficiency Virus 1 Tat Protein. Life (Basel) 2023; 13:life13040949. [PMID: 37109478 PMCID: PMC10144703 DOI: 10.3390/life13040949] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/20/2023] [Accepted: 03/30/2023] [Indexed: 04/08/2023] Open
Abstract
Sirtuins are NAD+-dependent protein lysine deacylases implicated in metabolic regulation and aging-related dysfunctions. The nuclear isoform Sirt1 deacetylates histones and transcription factors and contributes, e.g., to brain and immune cell functions. Upon infection by human immunodeficiency virus 1 (HIV1), Sirt1 deacetylates the viral transactivator of transcription (Tat) protein to promote the expression of the viral genome. Tat, in turn, inhibits Sirt1, leading to the T cell hyperactivation associated with HIV infection. Here, we describe the molecular mechanism of Tat-dependent sirtuin inhibition. Using Tat-derived peptides and recombinant Tat protein, we mapped the inhibitory activity to Tat residues 34–59, comprising Tat core and basic regions and including the Sirt1 deacetylation site Lys50. Tat binds to the sirtuin catalytic core and inhibits Sirt1, Sirt2, and Sirt3 with comparable potencies. Biochemical data and crystal structures of sirtuin complexes with Tat peptides reveal that Tat exploits its intrinsically extended basic region for binding to the sirtuin substrate binding cleft through substrate-like β-strand interactions, supported by charge complementarity. Tat Lys50 is positioned in the sirtuin substrate lysine pocket, although binding and inhibition do not require prior acetylation and rely on subtle differences to the binding of regular substrates. Our results provide mechanistic insights into sirtuin regulation by Tat, improving our understanding of physiological sirtuin regulation and the role of this interaction during HIV1 infection.
Collapse
Affiliation(s)
- Ramona S. Adolph
- Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Eileen Beck
- Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Kristian Schweimer
- Department of Biopolymers, University of Bayreuth, 95440 Bayreuth, Germany
| | - Andrea Di Fonzo
- Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Michael Weyand
- Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Paul Rösch
- Department of Biopolymers, University of Bayreuth, 95440 Bayreuth, Germany
| | - Birgitta M. Wöhrl
- Department of Biopolymers, University of Bayreuth, 95440 Bayreuth, Germany
| | - Clemens Steegborn
- Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
2
|
P300-mediated NEDD4 acetylation drives ebolavirus VP40 egress by enhancing NEDD4 ligase activity. PLoS Pathog 2021; 17:e1009616. [PMID: 34111220 PMCID: PMC8191996 DOI: 10.1371/journal.ppat.1009616] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023] Open
Abstract
The final stage of Ebola virus (EBOV) replication is budding from host cells, where the matrix protein VP40 is essential for driving this process. Many post-translational modifications such as ubiquitination are involved in VP40 egress, but acetylation has not been studied yet. Here, we characterize NEDD4 is acetylated at a conserved Lys667 mediated by the acetyltransferase P300 which drives VP40 egress process. Importantly, P300-mediated NEDD4 acetylation promotes NEDD4-VP40 interaction which enhances NEDD4 E3 ligase activity and is essential for the activation of VP40 ubiquitination and subsequent egress. Finally, we find that Zaire ebolavirus production is dramatically reduced in P300 knockout cell lines, suggesting that P300-mediated NEDD4 acetylation may have a physiological effect on Ebola virus life cycle. Thus, our study identifies an acetylation-dependent regulatory mechanism that governs VP40 ubiquitination and provides insights into how acetylation controls EBOV VP40 egress. Ebola virus (EBOV) is one of the deadliest pathogens, causing fatal hemorrhagic fever diseases in humans and primates. In this study, we find that P300-mediated NEDD4 acetylation facilitates EBOV egress. Acetylation promotes NEDD4-VP40 interactions which enhances NEDD4 E3 ligase activity and is essential for the activation of VP40 ubiquitination and subsequent egress. This study implies that inhibitory effect of acetylation can be regarded as an attractive candidate of drug target for the treatment of Ebola virus disease.
Collapse
|
3
|
Raghav PK, Kalyanaraman K, Kumar D. Human cell receptors: potential drug targets to combat COVID-19. Amino Acids 2021; 53:813-842. [PMID: 33950300 PMCID: PMC8097256 DOI: 10.1007/s00726-021-02991-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 04/21/2021] [Indexed: 01/08/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the coronavirus disease 2019 (COVID-19). The World Health Organization (WHO) has announced that COVID-19 is a pandemic having a higher spread rate rather than the mortality. Identification of a potential approach or therapy against COVID-19 is still under consideration. Therefore, it is essential to have an insight into SARS-CoV-2, its interacting partner, and domains for an effective treatment. The present study is divided into three main categories, including SARS-CoV-2 prominent receptor and its expression levels, other interacting partners, and their binding domains. The first section focuses primarily on coronaviruses' general aspects (SARS-CoV-2, SARS-CoV, and the Middle East Respiratory Syndrome Coronaviruses (MERS-CoV)) their structures, similarities, and mode of infections. The second section discusses the host receptors which includes the human targets of coronaviruses like dipeptidyl peptidase 4 (DPP4), CD147, CD209L, Angiotensin-Converting Enzyme 2 (ACE2), and other miscellaneous targets (type-II transmembrane serine proteases (TTSPs), furin, trypsin, cathepsins, thermolysin, elastase, phosphatidylinositol 3-phosphate 5-kinase, two-pore segment channel, and epithelium sodium channel C-α subunit). The human cell receptor, ACE2 plays an essential role in the Renin-Angiotensin system (RAS) pathway and COVID-19. Thus, this section also discusses the ACE2 expression and risk of COVID-19 infectivity in various organs and tissues such as the liver, lungs, intestine, heart, and reproductive system in the human body. Absence of ACE2 protein expression in immune cells could be used for limiting the SARS-CoV-2 infection. The third section covers the current available approaches for COVID-19 treatment. Overall, this review focuses on the critical role of human cell receptors involved in coronavirus pathogenesis, which would likely be used in designing target-specific drugs to combat COVID-19.
Collapse
Affiliation(s)
| | - Keerthana Kalyanaraman
- Amity Institute of Biotechnology, Amity University, Sector-125, Noida, Uttar Pradesh, India
| | - Dinesh Kumar
- ICMR-National Institute of Cancer Prevention & Research, Noida, 201301, India.
| |
Collapse
|
4
|
Ma L, Chen S, Wang Z, Guo S, Zhao J, Yi D, Li Q, Liu Z, Guo F, Li X, Jia P, Ding J, Liang C, Cen S. The CREB Regulated Transcription Coactivator 2 Suppresses HIV-1 Transcription by Preventing RNA Pol II from Binding to HIV-1 LTR. Virol Sin 2021; 36:796-809. [PMID: 33723808 DOI: 10.1007/s12250-021-00363-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/09/2020] [Indexed: 10/21/2022] Open
Abstract
The CREB-regulated transcriptional co-activators (CRTCs), including CRTC1, CRTC2 and CRTC3, enhance transcription of CREB-targeted genes. In addition to regulating host gene expression in response to cAMP, CRTCs also increase the infection of several viruses. While human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) promoter harbors a cAMP response element and activation of the cAMP pathway promotes HIV-1 transcription, it remains unknown whether CRTCs have any effect on HIV-1 transcription and HIV-1 infection. Here, we reported that CRTC2 expression was induced by HIV-1 infection, but CRTC2 suppressed HIV-1 infection and diminished viral RNA expression. Mechanistic studies revealed that CRTC2 inhibited transcription from HIV-1 LTR and diminished RNA Pol II occupancy at the LTR independent of its association with CREB. Importantly, CRTC2 inhibits the activation of latent HIV-1. Together, these data suggest that in response to HIV-1 infection, cells increase the expression of CRTC2 which inhibits HIV-1 gene expression and may play a role in driving HIV-1 into latency.
Collapse
Affiliation(s)
- Ling Ma
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China
| | - Shumin Chen
- Department of Blood Transfusion, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Zhen Wang
- Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, QC, H3T 1E2, Canada
| | - Saisai Guo
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China
| | - Jianyuan Zhao
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China
| | - Dongrong Yi
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China
| | - Quanjie Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China
| | - Zhenlong Liu
- Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, QC, H3T 1E2, Canada
| | - Fei Guo
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100176, China
| | - Xiaoyu Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China
| | - Pingping Jia
- Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China
| | - Jiwei Ding
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China. .,CAMS Key Laboratory of Antiviral Drug Research, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100050, China.
| | - Chen Liang
- Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, QC, H3T 1E2, Canada
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical School, Beijing, 100050, China. .,CAMS Key Laboratory of Antiviral Drug Research, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100050, China. .,Beijing Friendship Hospital, Capital Medical University, Beijing, 100029, China.
| |
Collapse
|
5
|
Sénécal V, Barat C, Tremblay MJ. The delicate balance between neurotoxicity and neuroprotection in the context of HIV-1 infection. Glia 2020; 69:255-280. [PMID: 32910482 DOI: 10.1002/glia.23904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 08/15/2020] [Accepted: 08/16/2020] [Indexed: 12/17/2022]
Abstract
Human immunodeficiency virus type-1 (HIV-1) causes a spectrum of neurological impairments, termed HIV-associated neurocognitive disorder (HAND), following the infiltration of infected cells into the brain. Even though the implementation of antiretroviral therapy reduced the systemic viral load, the prevalence of HAND remains unchanged and infected patients develop persisting neurological disturbances affecting their quality of life. As a result, HAND have gained importance in basic and clinical researches, warranting the need of developing new adjunctive treatments. Nonetheless, a better understanding of the molecular and cellular mechanisms remains necessary. Several studies consolidated their efforts into elucidating the neurotoxic signaling leading to HAND including the deleterious actions of HIV-1 viral proteins and inflammatory mediators. However, the scope of these studies is not sufficient to address all the complexity related to HAND development. Fewer studies focused on an altered neuroprotective capacity of the brain to respond to HIV-1 infection. Neurotrophic factors are endogenous polyproteins involved in neuronal survival, synaptic plasticity, and neurogenesis. Any defects in the processing or production of these crucial factors might compose a risk factor rendering the brain more vulnerable to neuronal damages. Due to their essential roles, they have been investigated for their diverse interplays with HIV-1 infection. In this review, we present a complete description of the neurotrophic factors involved in HAND. We discuss emerging concepts for their therapeutic applications and summarize the complex mechanisms that down-regulate their production in favor of a neurotoxic environment. For certain factors, we finally address opposing roles that rather lead to increased inflammation.
Collapse
Affiliation(s)
- Vincent Sénécal
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du CHU de Québec-Université Laval, Pavillon CHUL, Québec, Quebec, Canada
| | - Corinne Barat
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du CHU de Québec-Université Laval, Pavillon CHUL, Québec, Quebec, Canada
| | - Michel J Tremblay
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du CHU de Québec-Université Laval, Pavillon CHUL, Québec, Quebec, Canada.,Département de Microbiologie-infectiologie et immunologie, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
| |
Collapse
|
6
|
Li C, Mousseau G, Valente ST. Tat inhibition by didehydro-Cortistatin A promotes heterochromatin formation at the HIV-1 long terminal repeat. Epigenetics Chromatin 2019; 12:23. [PMID: 30992052 PMCID: PMC6466689 DOI: 10.1186/s13072-019-0267-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/30/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Transcription from the integrated HIV-1 promoter is directly governed by its chromatin environment, and the nucleosome-1 downstream from the transcription start site directly impedes transcription from the HIV-1 promoter. The HIV-1 Tat protein regulates the passage from viral latency to active transcription by binding to the viral mRNA hairpin (TAR) and recruiting transcriptional factors to promote transcriptional elongation. The Tat inhibitor didehydro-Cortistatin A (dCA) inhibits transcription and overtime, the lack of low-grade transcriptional events, triggers epigenetic changes at the latent loci that "lock" HIV transcription in a latent state. RESULTS Here we investigated those epigenetic changes using multiple cell line models of HIV-1 latency and active transcription. We demonstrated that dCA treatment does not alter the classic nucleosome positioning at the HIV-1 promoter, but promotes tighter nucleosome/DNA association correlating with increased deacetylated H3 occupancy at nucleosome-1. Recruitment of the SWI/SNF chromatin remodeling complex PBAF, necessary for Tat-mediated transactivation, is also inhibited, while recruitment of the repressive BAF complex is enhanced. These results were supported by loss of RNA polymerase II recruitment on the HIV genome, even during strong stimulation with latency-reversing agents. No epigenetic changes were detected in cell line models of latency with Tat-TAR incompetent proviruses confirming the specificity of dCA for Tat. CONCLUSIONS We characterized the dCA-mediated epigenetic signature on the HIV genome, which translates into potent blocking effects on HIV expression, further strengthening the potential of Tat inhibitors in "block-and-lock" functional cure approaches.
Collapse
Affiliation(s)
- Chuan Li
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Guillaume Mousseau
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA
| | - Susana T Valente
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, FL, USA.
| |
Collapse
|
7
|
Nookala AR, Schwartz DC, Chaudhari NS, Glazyrin A, Stephens EB, Berman NEJ, Kumar A. Methamphetamine augment HIV-1 Tat mediated memory deficits by altering the expression of synaptic proteins and neurotrophic factors. Brain Behav Immun 2018; 71:37-51. [PMID: 29729322 PMCID: PMC6003882 DOI: 10.1016/j.bbi.2018.04.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 04/29/2018] [Accepted: 04/30/2018] [Indexed: 01/06/2023] Open
Abstract
Methamphetamine (METH) abuse is common among individuals infected with HIV-1 and has been shown to affect HIV replication and pathogenesis. These HIV-1 infected individuals also exhibit greater neuronal injury and higher cognitive decline. HIV-1 proteins, specifically gp120 and HIV-1 Tat, have been earlier shown to affect neurocognition. HIV-1 Tat, a viral protein released early during HIV-1 replication, contributes to HIV-associated neurotoxicity through various mechanisms including production of pro-inflammatory cytokines, reactive oxygen species and dysregulation of neuroplasticity. However, the combined effect of METH and HIV-1 Tat on neurocognition and its potential effect on neuroplasticity mechanisms remains largely unknown. Therefore, the present study was undertaken to investigate the combined effect of METH and HIV-1 Tat on behavior and on the expression of neuroplasticity markers by utilizing Doxycycline (DOX)-inducible HIV-1 Tat (1-86) transgenic mice. Expression of Tat in various brain regions of these mice was confirmed by RT-PCR. The mice were administered with an escalating dose of METH (0.1 mg/kg to 6 mg/kg, i.p) over a 7-day period, followed by 6 mg/kg, i.p METH twice a day for four weeks. After three weeks of METH administration, Y maze and Morris water maze assays were performed to determine the effect of Tat and METH on working and spatial memory, respectively. Compared with controls, working memory was significantly decreased in Tat mice that were administered METH. Moreover, significant deficits in spatial memory were also observed in Tat-Tg mice that were administered METH. A significant reduction in the protein expressions of synapsin 1, synaptophysin, Arg3.1, PSD-95, and BDNF in different brain regions were also observed. Expression levels of Calmodulin kinase II (CaMKII), a marker of synaptodendritic integrity, were also significantly decreased in HIV-1 Tat mice that were treated with METH. Together, this data suggests that METH enhances HIV-1 Tat-induced memory deficits by reducing the expression of pre- and postsynaptic proteins and neuroplasticity markers, thus providing novel insights into the molecular mechanisms behind neurocognitive impairments in HIV-infected amphetamine users.
Collapse
Affiliation(s)
- Anantha Ram Nookala
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - Daniel C. Schwartz
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - Nitish S. Chaudhari
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - Alexy Glazyrin
- Department of Pathology, School of Medicine, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, 64108, USA
| | - Edward B. Stephens
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nancy E. J. Berman
- Department of Anatomy and Cell biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Anil Kumar
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA.
| |
Collapse
|
8
|
Abstract
INTRODUCTION Epigenetic regulators including writers, erasers, and readers of chromatin marks have been implicated in numerous diseases and are therefore subject of intense academic and pharmaceutical research. While several small-molecule inhibitors targeting writers or erasers are either approved drugs or are currently being evaluated in clinical trials, the targeting of epigenetic readers has lagged behind. Proof-of-principle that epigenetic readers are also relevant drug targets was provided by landmark discoveries of selective inhibitors targeting the BET family of acetyl-lysine readers. More recently, high affinity chemical probes for non-BET acetyl- and methyl-lysine reader domains have also been developed. Areas covered: This article covers recent advances with the identification and validation of inhibitors and chemical probes targeting epigenetic reader domains. Issues related to epigenetic reader druggability, quality requirements for chemical probes, interpretation of cellular action, unexpected cross-talk, and future challenges are also discussed. Expert opinion: Chemical probes provide a powerful means to unravel biological functions of epigenetic readers and evaluate their potential as drug targets. To yield meaningful results, potency, selectivity, and cellular target engagement of chemical probes need to be stringently validated. Future chemical probes will probably need to fulfil additional criteria such as strict target specificity or the targeting of readers within protein complexes.
Collapse
Affiliation(s)
- Holger Greschik
- a Urologische Klinik und Zentrale Klinische Forschung , Universitätsklinikum Freiburg, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg , Freiburg , Germany
| | - Roland Schüle
- a Urologische Klinik und Zentrale Klinische Forschung , Universitätsklinikum Freiburg, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg , Freiburg , Germany.,b Deutsches Konsortium für Translationale Krebsforschung, Standort Freiburg , Freiburg , Germany.,c BIOSS Centre of Biological Signalling Studies , Albert-Ludwigs-University Freiburg , Freiburg , Germany
| | - Thomas Günther
- a Urologische Klinik und Zentrale Klinische Forschung , Universitätsklinikum Freiburg, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg , Freiburg , Germany
| |
Collapse
|
9
|
Bonnaud EM, Suberbielle E, Malnou CE. Histone acetylation in neuronal (dys)function. Biomol Concepts 2017; 7:103-16. [PMID: 27101554 DOI: 10.1515/bmc-2016-0002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 02/25/2016] [Indexed: 02/05/2023] Open
Abstract
Cognitive functions require the expression of an appropriate pattern of genes in response to environmental stimuli. Over the last years, many studies have accumulated knowledge towards the understanding of molecular mechanisms that regulate neuronal gene expression. Epigenetic modifications have been shown to play an important role in numerous neuronal functions, from synaptic plasticity to learning and memory. In particular, histone acetylation is a central player in these processes. In this review, we present the molecular mechanisms of histone acetylation and summarize the data underlying the relevance of histone acetylation in cognitive functions in normal and pathological conditions. In the last part, we discuss the different mechanisms underlying the dysregulation of histone acetylation associated with neurological disorders, with a particular focus on environmental causes (stress, drugs, or infectious agents) that are linked to impaired histone acetylation.
Collapse
|
10
|
Rahimian P, He JJ. HIV-1 Tat-shortened neurite outgrowth through regulation of microRNA-132 and its target gene expression. J Neuroinflammation 2016; 13:247. [PMID: 27634380 PMCID: PMC5025601 DOI: 10.1186/s12974-016-0716-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/08/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Synaptodendritic damage is a pathological hallmark of HIV-associated neurocognitive disorders, and HIV-1 Tat protein is known to cause such injury in the central nervous system. In this study, we aimed to determine the molecular mechanisms of Tat-induced neurite shortening, specifically the roles of miR-132, an important regulator of neurite morphogenesis in this process. METHODS The relationship between Tat expression and miR-132 expression was first determined using reverse transcription quantitative PCR (qRT-PCR) in Tat-transfected astrocytes and neurons, astrocytes from Tat-transgenic mice, and HIV-infected astrocytes. qRT-PCR and Western blotting were performed to determine Tat effects on expression of miR-132 target genes methyl CpG-binding protein 2, Rho GTPase activator p250GAP, and brain-derived neurotrophic factor. Exosomes were isolated from Tat-expressing astrocytes, and exosomal microRNA (miRNA) uptake into neurons was studied using miRNA labeling and flow cytometry. The lactate dehydrogenase release was used to determine the cytotoxicity, while immunostaining was used to determine neurite lengths and synapse formation. Tat basic domain deletion mutant and miR-132 mimic and inhibitor were used to determine the specificity of the relationship between Tat and miR-132 and its effects on astrocytes and neurons and the underlying mechanisms of Tat-induced miR-132 expression. RESULTS Tat significantly induced miR-132 expression, ensuing down-regulation of miR-132 target genes in astrocytes and neurons. miR-132 induction was associated with phosphorylation of cAMP response element-binding protein and required the basic domain of Tat. miRNA-132 induction had no effects on astrocyte activation or survival but was involved in the direct neurotoxicity of Tat. miR-132 was present in astrocyte-derived exosomes and was taken up by neurons, causing neurite shortening. CONCLUSIONS Tat-induced miR-132 expression contributes to both direct and astrocyte-mediated Tat neurotoxicity and supports the important roles of miR-132 in controlling neurite outgrowth.
Collapse
Affiliation(s)
- Pejman Rahimian
- Department of Cell Biology and Immunology, Graduate School of Biomedical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107 USA
| | - Johnny J. He
- Department of Cell Biology and Immunology, Graduate School of Biomedical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107 USA
| |
Collapse
|
11
|
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
Collapse
Affiliation(s)
- Guangdi Li
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| | - Erik De Clercq
- KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| |
Collapse
|
12
|
HIV Genome-Wide Protein Associations: a Review of 30 Years of Research. Microbiol Mol Biol Rev 2016; 80:679-731. [PMID: 27357278 DOI: 10.1128/mmbr.00065-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
Collapse
|
13
|
A Small Molecule Activator of p300/CBP Histone Acetyltransferase Promotes Survival and Neurite Growth in a Cellular Model of Parkinson’s Disease. Neurotox Res 2016; 30:510-20. [DOI: 10.1007/s12640-016-9636-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/23/2016] [Accepted: 05/25/2016] [Indexed: 01/20/2023]
|
14
|
Aralaguppe SPG, Sharma S, Menon M, Prasad VR, Saravanan S, Murugavel KG, Solomon S, Ranga U. The Evolving Profile of the Signature Amino Acid Residues in HIV-1 Subtype C Tat. AIDS Res Hum Retroviruses 2016; 32:503-14. [PMID: 26678403 DOI: 10.1089/aid.2015.0208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Using several HIV-1 tat exon 1 amino acid sequences available from public databases and additional sequences derived from a southern Indian clinical cohort, we compared the profile of the signature amino acid residues (SAR) between two different time periods, 1986-2004 and 2005-2014. The analysis identified eight positions as signature residues in subtype C Tat and demonstrated a changing pattern at four of these positions between the two periods. At three locations (histidine 29, serine 57, and proline 60), there appears to be a nonuniform negative selection against the SAR. The negative selection appears to be severe, especially against histidine 29 (p < .0001) and moderate against proline 60 (p < .0001). The negative selection against serine 57 is statistically insignificant and appears to have begun recently. At position 63, the frequency of signature residue glutamic acid increased over the past decade, although the difference was not significant. Importantly, at the three locations where the negative selection is in progress, the substitute amino acids are the generic residues present in most of the other HIV-1 subtypes. Our data demonstrate that viral evolution can subject specific amino acid residues to subtle and progressive selection pressures without affecting the prevalence of other amino acid residues.
Collapse
Affiliation(s)
- Shambhu Prasad G. Aralaguppe
- Molecular Biology and Genetics Unit, HIV-AIDS Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Shilpee Sharma
- Molecular Biology and Genetics Unit, HIV-AIDS Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Malini Menon
- Molecular Biology and Genetics Unit, HIV-AIDS Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Vinayaka R. Prasad
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, New York
| | | | | | - Suniti Solomon
- YRG Centre for AIDS Research and Education, Chennai, India
| | - Udaykumar Ranga
- Molecular Biology and Genetics Unit, HIV-AIDS Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| |
Collapse
|
15
|
Jeng MY, Ali I, Ott M. Manipulation of the host protein acetylation network by human immunodeficiency virus type 1. Crit Rev Biochem Mol Biol 2015; 50:314-25. [PMID: 26329395 PMCID: PMC4816045 DOI: 10.3109/10409238.2015.1061973] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Over the past 15 years, protein acetylation has emerged as a globally important post-translational modification that fine-tunes major cellular processes in many life forms. This dynamic regulatory system is critical both for complex eukaryotic cells and for the viruses that infect them. HIV-1 accesses the host acetylation network by interacting with several key enzymes, thereby promoting infection at multiple steps during the viral life cycle. Inhibitors of host histone deacetylases and bromodomain-containing proteins are now being pursued as therapeutic strategies to enhance current antiretroviral treatment. As more acetylation-targeting compounds are reaching clinical trials, it is time to review the role of reversible protein acetylation in HIV-infected CD4(+) T cells.
Collapse
Affiliation(s)
- Mark Y. Jeng
- Gladstone Institute of Virology and Immunology, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, CA 94158, USA
| | - Ibraheem Ali
- Gladstone Institute of Virology and Immunology, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, CA 94158, USA
| | - Melanie Ott
- Gladstone Institute of Virology and Immunology, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, CA 94158, USA
| |
Collapse
|
16
|
Johri MK, Sharma N, Singh SK. HIV Tat protein: Is Tat-C much trickier than Tat-B? J Med Virol 2015; 87:1334-43. [PMID: 25879536 DOI: 10.1002/jmv.24182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2015] [Indexed: 01/25/2023]
Abstract
Out of various subtypes of human immunodeficiency virus type 1 (HIV-1), subtype B and C cause most of the infections worldwide. Clade specific differences have been reported in differences in clinical picture of HIV pathogenesis. Transcription of the HIV-1 genome is regulated by the interaction of HIV Tat protein to the trans-activation response (TAR) element. The differential binding of clade B and C Tat proteins to TAR and differences in activation of NF-κB cascade leading to differential transactivation capacity and cytokine expression has been examined in this study. More stable Tat-TAR complex formation by Tat-C revealed by EMSA and higher TNF-α expression shown by Tat-C compared to Tat-B leads to higher NF-κB activation, which may be plausible cause for higher transactivation by Tat-C as obtained by FACS analysis. This comparative study would be helpful in understanding the basic mechanism of clade specific Tat protein differences and their functional relationships.
Collapse
Affiliation(s)
- Manish Kumar Johri
- Laboratory of Neurovirology and Inflammation Biology, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500007, India
| | - Nikhil Sharma
- Laboratory of Neurovirology and Inflammation Biology, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500007, India
| | - Sunit K Singh
- Laboratory of Neurovirology and Inflammation Biology, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500007, India
| |
Collapse
|
17
|
Kukkonen S, Martinez-Viedma MDP, Kim N, Manrique M, Aldovini A. HIV-1 Tat second exon limits the extent of Tat-mediated modulation of interferon-stimulated genes in antigen presenting cells. Retrovirology 2014; 11:30. [PMID: 24742347 PMCID: PMC4036831 DOI: 10.1186/1742-4690-11-30] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/27/2014] [Indexed: 12/14/2022] Open
Abstract
Background We have shown that HIV-1 Tat interaction with MAP2K3, MAP2K6, and IRF7 promoters is key to IFN-stimulated genes (ISG) activation in immature dendritic cells and macrophages. Results We evaluated how Tat alleles and mutants differ in cellular gene modulation of immature dendritic cells and monocyte-derived macrophages and what similarities this modulation has with that induced by interferons. The tested alleles and mutants modulated to different degrees ISG, without concomitant induction of interferons. The first exon TatSF21-72 and the minimal transactivator TatSF21-58, all modulated genes to a significantly greater extent than full-length wild type, two-exon Tat, indicating that Tat second exon is critical in reducing the innate response triggered by HIV-1 in these cells. Mutants with reduced LTR transactivation had a substantially reduced effect on host gene expression modulation than wild type TatSF2. However, the more potent LTR transactivator TatSF2A58T modulated ISG expression to a lower degree compared to TatSF2. A cellular gene modulation similar to that induced by Tat and Tat mutants in immature dendritic cells could be observed in monocyte-derived macrophages, with the most significant pathways affected by Tat being the same in both cell types. Tat expression in cells deleted of the type I IFN locus or receptor resulted in a gene modulation pattern similar to that induced in primary immature dendritic cells and monocyte-derived macrophages, excluding the involvement of type I IFNs in Tat-mediated gene modulation. ISG activation depends on Tat interaction with MAP2K3, MAP2K6, and IRF7 promoters and a single exon Tat protein more strongly modulated the luciferase activity mediated by MAP2K3, MAP2K6, and IRF7 promoter sequences located 5′ of the RNA start site than the wild type two-exon Tat, while a cysteine and lysine Tat mutants, reduced in LTR transactivation, had negligible effects on these promoters. Chemical inhibition of CDK9 or Sp1 decreased Tat activation of MAP2K3-, MAP2K6-, and IRF7-mediated luciferase transcription. Conclusions Taken together, these data indicate that the second exon of Tat is critical to the containment of the innate response stimulated by Tat in antigen presenting cells and support a role for Tat in stimulating cellular transcription via its interaction with transcription factors present at promoters.
Collapse
Affiliation(s)
| | | | | | | | - Anna Aldovini
- Department of Pediatrics, Harvard Medical School, Department of Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
| |
Collapse
|
18
|
Dhamija N, Rawat P, Mitra D. Epigenetic regulation of HIV-1 persistence and evolving strategies for virus eradication. Subcell Biochem 2013; 61:479-505. [PMID: 23150264 DOI: 10.1007/978-94-007-4525-4_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Despite the intense effort put by researchers globally to understand Human Immunodeficiency Virus (HIV-1) pathogenesis since its discovery 30 years ago, the acquired knowledge till date is not good enough to eradicate HIV-1 from an infected individual. HIV-1 infects cells of the human immune system and integrates into the host cell genome thereby leading to persistent infection in these cells. Based on the activation status of the cells, the infection could be productive or result in latent infection. The current regimen used to treat HIV-1 infection in an AIDS patient includes combination of antiretroviral drugs called Highly Active Anti-Retroviral Therapy (HAART). A major challenge for the success of HAART has been these latent reservoirs of HIV which remain hidden and pose major hurdle for the eradication of virus. Combination of HAART therapy with simultaneous activation of latent reservoirs of HIV-1 seems to be the future of anti-retroviral therapy; however, this will require a much better understanding of the mechanisms and regulation of HIV-1 latency. In this chapter, we have tried to elaborate on HIV-1 latency, highlighting the strategies employed by the virus to ensure persistence in the host with specific focus on epigenetic regulation of latency. A complete understanding of HIV-1 latency will be extremely essential for ultimate eradication of HIV-1 from the human host.
Collapse
Affiliation(s)
- Neeru Dhamija
- National Centre for Cell Science, NCCS Complex, Pune University Campus, Ganeshkhind, Pune, 411007, India
| | | | | |
Collapse
|
19
|
Impact of Tat Genetic Variation on HIV-1 Disease. Adv Virol 2012; 2012:123605. [PMID: 22899925 PMCID: PMC3414192 DOI: 10.1155/2012/123605] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 05/14/2012] [Indexed: 01/08/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) promoter or long-terminal repeat (LTR) regulates viral gene expression by interacting with multiple viral and host factors. The viral transactivator protein Tat plays an important role in transcriptional activation of HIV-1 gene expression. Functional domains of Tat and its interaction with transactivation response element RNA and cellular transcription factors have been examined. Genetic variation within tat of different HIV-1 subtypes has been shown to affect the interaction of the viral transactivator with cellular and/or viral proteins, influencing the overall level of transcriptional activation as well as its action as a neurotoxic protein. Consequently, the genetic variability within tat may impact the molecular architecture of functional domains of the Tat protein that may impact HIV pathogenesis and disease. Tat as a therapeutic target for anti-HIV drugs has also been discussed.
Collapse
|
20
|
Dahiya S, Nonnemacher MR, Wigdahl B. Deployment of the human immunodeficiency virus type 1 protein arsenal: combating the host to enhance viral transcription and providing targets for therapeutic development. J Gen Virol 2012; 93:1151-1172. [PMID: 22422068 DOI: 10.1099/vir.0.041186-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Despite the success of highly active antiretroviral therapy in combating human immunodeficiency virus type 1 (HIV-1) infection, the virus still persists in viral reservoirs, often in a state of transcriptional silence. This review focuses on the HIV-1 protein and regulatory machinery and how expanding knowledge of the function of individual HIV-1-coded proteins has provided valuable insights into understanding HIV transcriptional regulation in selected susceptible cell types. Historically, Tat has been the most studied primary transactivator protein, but emerging knowledge of HIV-1 transcriptional regulation in cells of the monocyte-macrophage lineage has more recently established that a number of the HIV-1 accessory proteins like Vpr may directly or indirectly regulate the transcriptional process. The viral proteins Nef and matrix play important roles in modulating the cellular activation pathways to facilitate viral replication. These observations highlight the cross talk between the HIV-1 transcriptional machinery and cellular activation pathways. The review also discusses the proposed transcriptional regulation mechanisms that intersect with the pathways regulated by microRNAs and how development of the knowledge of chromatin biology has enhanced our understanding of key protein-protein and protein-DNA interactions that form the HIV-1 transcriptome. Finally, we discuss the potential pharmacological approaches to target viral persistence and enhance effective transcription to purge the virus in cellular reservoirs, especially within the central nervous system, and the novel therapeutics that are currently in various stages of development to achieve a much superior prognosis for the HIV-1-infected population.
Collapse
Affiliation(s)
- Satinder Dahiya
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| |
Collapse
|
21
|
Abstract
Foamy viruses (FVs) are distinct members of the retrovirus (RV) family. In this chapter, the molecular regulation of foamy viral transcription, splicing, polyadenylation, and RNA export will be compared in detail to the orthoretroviruses. Foamy viral transcription is regulated in early and late phases, which are separated by the usage of two promoters. The viral transactivator protein Tas activates both promoters. The nature of this early-late switch and the molecular mechanism used by Tas are unique among RVs. RVs duplicate the long terminal repeats (LTRs) during reverse transcription. These LTRs carry both a promoter region and functional poly(A) sites. In order to express full-length transcripts, RVs have to silence the poly(A) signal in the 5' LTR and to activate it in the 3' LTR. FVs have a unique R-region within these LTRs with a major splice donor (MSD) at +51 followed by a poly(A) signal. FVs use a MSD-dependent mechanism to inactivate the polyadenylation. Most RVs express all their genes from a single primary transcript. In order to allow expression of more than one gene from this RNA, differential splicing is extensively used in complex RVs. The splicing pattern of FV is highly complex. In contrast to orthoretroviruses, FVs synthesize the Pol precursor protein from a specific and spliced transcript. The LTR and IP-derived primary transcripts are spliced into more than 15 different mRNA species. Since the RNA ratios have to be balanced, a tight regulation of splicing is required. Cellular quality control mechanisms retain and degrade unspliced or partially spliced RNAs in the nucleus. In this review, I compare the RNA export pathways used by orthoretroviruses with the distinct RNA export pathway used by FV. All these steps are highly regulated by host and viral factors and set FVs apart from all other RVs.
Collapse
Affiliation(s)
- Jochen Bodem
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| |
Collapse
|
22
|
Zou S, Fitting S, Hahn YK, Welch SP, El-Hage N, Hauser KF, Knapp PE. Morphine potentiates neurodegenerative effects of HIV-1 Tat through actions at μ-opioid receptor-expressing glia. Brain 2011; 134:3616-31. [PMID: 22102648 DOI: 10.1093/brain/awr281] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Individuals infected with human immunodeficiency virus-1 who abuse opiates can have a higher incidence of virus-associated neuropathology. Human immunodeficiency virus does not infect neurons, but viral proteins such as transactivator of transcription and glycoprotein 120, originating from infected glia, are neurotoxic. Moreover, functional changes in glial cells that enhance inflammation and reduce trophic support are increasingly implicated in human immunodeficiency virus neuropathology. In previous studies, co-exposure with morphine enhanced transactivator of transcription neurotoxicity towards cultured striatal neurons. Since those cultures contained µ-opioid receptor-expressing astroglia and microglia, and since glia are the principal site of infection in the central nervous system, we hypothesized that morphine synergy might be glially mediated. A 60 hour, repeated measures paradigm and multiple co-culture models were used to investigate the cellular basis for opiate-enhanced human immunodeficiency virus neurotoxicity. Morphine co-exposure significantly enhanced transactivator of transcription-induced neuron death when glia were present. Synergistic effects of morphine on transactivator of transcription neurotoxicity were greatest with neuron-glia contact, but also occurred to a lesser extent with glial conditioned medium. Importantly, synergy was lost if glia, but not neurons, lacked µ-opioid receptors, indicating that opiate interactions with human immunodeficiency virus converge at the level of µ-opioid receptor-expressing glia. Morphine enhanced transactivator of transcription-induced inflammatory effectors released by glia, elevating reactive oxygen species, increasing 3-nitrotyrosine production by microglia, and reducing the ability of glia to buffer glutamate. But neuron survival was reduced even more with glial contact than with exposure to conditioned medium, suggesting that noxious elements associated with cell contact augment the toxicity due to soluble factors. Similar morphine-transactivator of transcription synergy was also observed in studies with the clade C sequence of HIV-1 transactivator of transcription, which did not cause neuron death unless morphine was present. Several paradoxical observations related to opiate effects were noted when µ-opioid receptors were specifically ablated from either glia or neurons. This suggests that µ-opioid receptor loss in isolated cell types can fundamentally distort cell-to-cell signalling, revealing opponent processes that may exist in individual cell types. Our findings show the critical role of glia in orchestrating neurotoxic interactions of morphine and transactivator of transcription, and support the emerging concept that combined exposure to opiates and human immunodeficiency virus drives enhanced pathology within the central nervous system.
Collapse
Affiliation(s)
- Shiping Zou
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | | | | | | | | | | | | |
Collapse
|
23
|
Zou W, Wang Z, Liu Y, Fan Y, Zhou BY, Yang XF, He JJ. Involvement of p300 in constitutive and HIV-1 Tat-activated expression of glial fibrillary acidic protein in astrocytes. Glia 2010; 58:1640-8. [PMID: 20578042 DOI: 10.1002/glia.21038] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
HIV-1 Tat protein is an important pathogenic factor in HIV-1-associated neurological diseases. One hallmark of HIV-1 infection of the central nervous system (CNS) is astrocytosis, which is characterized by elevated glial fibrillary acidic protein (GFAP) expression in astrocytes. We have shown that Tat activates GFAP expression in astrocytes [Zhou et al., (2004) Mol Cell Neurosci 27:296-305] and that GFAP is an important regulator of Tat neurotoxicity [Zou et al., (2007) Am J Pathol 171:1293-1935]. However, the underlying mechanisms for Tat-mediated GFAP up-regulation are not understood. In this study, we reported concurrent up-regulation of adenovirus E1a-associated 300 kDa protein p300 and GFAP in Tat-expressing human astrocytoma cells and primary astrocytes. We showed that p300 was indeed induced by Tat expression and HIV-1 infection and that the induction occurred at the transcriptional level through the cis-acting elements of early growth response 1 (egr-1) within its promoter. Using siRNA, we further showed that p300 regulated both constitutive and Tat-mediated GFAP expression. Moreover, we showed that ectopic expression of p300 potentiated Tat transactivation activity and increased proliferation of HIV-1-infected astrocytes, but had little effect on HIV-1 replication in these cells. Taken together, these results demonstrate for the first time that Tat is a positive regulator of p300 expression, which in turn regulates GFAP expression, and suggest that the Tat-Egr-1-p300-GFAP axis likely contributes to Tat neurotoxicity and predisposes astrocytes to be an HIV-1 sanctuary in the CNS.
Collapse
Affiliation(s)
- Wei Zou
- Department of Internal Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Infection with E1B-mutant adenovirus stabilizes p53 but blocks p53 acetylation and activity through E1A. Oncogene 2010; 30:865-75. [PMID: 20935676 DOI: 10.1038/onc.2010.461] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Wild-type adenovirus type 5 eliminates p53 through the E1B-55kDa and E4-34kDa gene products. Deletion or mutation of E1B-55kDa has long been thought to confer p53-selective replication of oncolytic viruses. We show here that infection with E1B-defective adenovirus mutants induces massive accumulation of p53, without obvious defects in p53 localization, phosphorylation, conformation and oligomerization. Nonetheless, p53 completely failed to induce its target genes in this scenario, for example, p21/CDKN1A, Mdm2 and PUMA. Two regions of the E1A gene products independently contributed to the suppression of p21 transcription. Depending on the E1A conserved region 3, E1B-defective adenovirus impaired the ability of the transcription factor Sp1 to bind the p21 promoter. Moreover, the amino terminal region of E1A, binding the acetyl transferases p300 and CREB-binding protein, blocked p53 K382 acetylation in infected cells. Mutating either of these E1A regions, in addition to E1B, partially restored p21 mRNA levels. Our findings argue that adenovirus attenuates p53-mediated p21 induction, through at least two E1B-independent mechanisms. Other virus species and cancer cells may employ analogous strategies to impair p53 activity.
Collapse
|
25
|
Kim N, Kukkonen S, Gupta S, Aldovini A. Association of Tat with promoters of PTEN and PP2A subunits is key to transcriptional activation of apoptotic pathways in HIV-infected CD4+ T cells. PLoS Pathog 2010; 6:e1001103. [PMID: 20862322 PMCID: PMC2940756 DOI: 10.1371/journal.ppat.1001103] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 08/13/2010] [Indexed: 11/25/2022] Open
Abstract
Apoptosis in HIV-1-infected CD4+ primary T cells is triggered by the alteration of the PI3K and p53 pathways, which converge on the FOXO3a transcriptional activator. Tat alone can cause activation of FOXO3a and of its proapoptotic target genes. To understand how Tat affects this pathway, we carried out ChIP-Chip experiments with Tat. Tat associates with the promoters of PTEN and two PP2A subunit genes, but not with the FOXO3a promoter. PTEN and PP2A encode phosphatases, whose levels and activity are increased when Tat is expressed. They counteract phosphorylation of Akt1 and FOXO3a, and so activate transcriptional activity of FOXO3a. FOXO3a promotes increased transcription of Egr-1, which can further stimulate the transcription of PTEN, thereby reinforcing the pathway that leads to FOXO3a transcriptional activation. RNAi experiments support the role of PTEN and PP2A in the initiation of the Tat-mediated cascade, which is critical to apoptosis. The increased accumulation of PTEN and PP2A subunit mRNAs during Tat expression is more likely to be the result of increased transcription initiation and not relief of promoter-proximal pausing of RNAPII. The Tat-PTEN and -PP2A promoter interactions provide a mechanistic explanation of Tat-mediated apoptosis in CD4+ T cells. HIV infection leads to the depletion of CD4+ T cells, the major viral cell target. The destruction of these cells can occur because of cytopathic effect or apoptosis. HIV Tat is one of the proteins that can contribute to the apoptotic process of both infected and uninfected cells, as it is released in the plasma and enter uninfected cells. Tat expression in CD4+ T-cells is linked to increased transcriptional activity of FOXO3a, a factor that targets the transcription of pro-apoptotic genes. The mechanism by which Tat leads to activation apoptotic pathways is by associating with the promoters of the phospatases PTEN and PP2A and by increasing their levels. The increased amount of these proteins leads to a decreased amount of pAKt1 and increased amount of non-phosphorylated FOXO3a, which migrates from the cytoplasm to the nucleus and increases the transcription of its proapoptotic target genes. These results, together with experiments that silence PTEN and PP2A and measure their activities, identify the association of Tat with PTEN and PP2A promoters as the initiating event of Tat-mediated apoptosis.
Collapse
Affiliation(s)
- Nayoung Kim
- Children's Hospital Boston, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston, Massachusetts, United States of America
| | - Sami Kukkonen
- Children's Hospital Boston, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston, Massachusetts, United States of America
| | - Sumeet Gupta
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Anna Aldovini
- Children's Hospital Boston, Department of Medicine, and Harvard Medical School, Department of Pediatrics, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
26
|
Romani B, Engelbrecht S, Glashoff RH. Functions of Tat: the versatile protein of human immunodeficiency virus type 1. J Gen Virol 2009; 91:1-12. [PMID: 19812265 DOI: 10.1099/vir.0.016303-0] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat is a multifunctional protein that contributes to several pathological symptoms of HIV-1 infection as well as playing a critical role in virus replication. Tat is a robust transactivating protein that induces a variety of effects by altering the expression levels of cellular and viral genes. The functions of Tat are therefore primarily related to its role in modulation of gene expression. In this review the functions of HIV-1 Tat that have been well documented, as well as a number of novel functions that have been proposed for this protein, are discussed. Since some of the functions of Tat vary in different cell types in a concentration-dependent manner and because Tat sometimes exerts the same activity through different pathways, study of this protein has at times yielded conflicting and controversial results. Due to its pivotal role in viral replication and in disease pathogenesis, Tat and the cellular pathways targeted by Tat are potential targets for new anti-HIV drugs.
Collapse
Affiliation(s)
- Bizhan Romani
- Division of Medical Virology, Department of Pathology, University of Stellenbosch, Tygerberg 7505, South Africa.
| | | | | |
Collapse
|
27
|
Increased phospholipase A2 activity and inflammatory response but decreased nerve growth factor expression in the olfactory bulbectomized rat model of depression: effects of chronic ethyl-eicosapentaenoate treatment. J Neurosci 2009; 29:14-22. [PMID: 19129380 DOI: 10.1523/jneurosci.3569-08.2009] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An increased inflammatory response and deficient synthesis of neurotrophic factors (NTFs) may contribute to the etiology of depression. However, the interrelationship between inflammation and NTFs is unknown. Recently, ethyl-eicosapentaenoate (EPA) has been used to treat depression. The mechanism by which EPA benefits depression is also unclear. Using the olfactory bulbectomized (OB) rat model of depression, this study evaluated two pathways from bulbectomy to the induction of depression-like changes (the inflammation-hypothalamic-pituitary-adrenal axis-stress response pathway and inflammation-nerve growth factor-memory pathway) and the effect of EPA on these pathways. When compared with sham-operated rats fed a control diet, significantly increased locomotor and rearing activities in an "open field," impaired memory in the Morris water maze, increased expression of corticotrophin-releasing factor (CRF), and increased secretion of corticosterone were found in OB rats. mRNA expression of nerve growth factor (NGF) was significantly lower in the hippocampus, and phospholipase A2 (PLA2) was higher in the hypothalamus; this change was associated with increased interleukin-1beta (IL-1beta) and prostaglandin E2 (PGE2) in the serum and brain. EPA treatments normalized these behavioral impairments and reduced CRF expression and corticosterone secretion. EPA also reduced serum concentrations of IL-1beta and PGE2, but reversed NGF reduction. Similar to the effects of EPA, the anti-inflammatory drug celecoxib significantly reduced blood PGE2, IL-1beta, and corticosterone concentrations and increased NGF expression in OB rats. Furthermore, anti-NGF treatment blocked EPA effects on behavior. These results suggest that an interaction exists between inflammation and NGF in the depression model. EPA may improve depression via its anti-inflammation properties and the upregulation of NGF.
Collapse
|
28
|
de la Vega L, Sánchez-Duffhues G, Fresno M, Schmitz ML, Muñoz E, Calzado MA. The 73 kDa subunit of the CPSF complex binds to the HIV-1 LTR promoter and functions as a negative regulatory factor that is inhibited by the HIV-1 Tat protein. J Mol Biol 2007; 372:317-30. [PMID: 17669424 DOI: 10.1016/j.jmb.2007.06.075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 06/20/2007] [Accepted: 06/26/2007] [Indexed: 11/19/2022]
Abstract
Gene expression in eukaryotes requires the post-transcriptional cleavage of mRNA precursors into mature mRNAs. The cleavage and polyadenylation specificity factor (CPSF) is critical for this process and its 73 kDa subunit (CPSF-73) mediates cleavage coupled to polyadenylation and histone pre-mRNA processing. Using CPSF-73 over-expression and siRNA-mediated knockdown experiments, this study identifies CPSF-73 as an important regulatory protein that represses the basal transcriptional activity of the HIV-1 LTR promoter. Similar results were found with over-expression of the CPSF-73 homologue RC-68, but not with CPSF 100 kDa subunit (CPSF-100) and RC-74. Chromatin immunoprecipitation assays revealed the physical interaction of CPSF-73 with the HIV-1 LTR promoter. Further experiments revealed indirect CPSF-73 binding to the region between -275 to -110 within the 5' upstream region. Functional assays revealed the importance for the 5' upstream region (-454 to -110) of the LTR for CPSF-73-mediated transcription repression. We also show that HIV-1 Tat protein interacts with CPSF-73 and counteracts its repressive activity on the HIV-1 LTR promoter. Our results clearly show a novel function for CPSF-73 and add another candidate protein for explaining the molecular mechanisms underlying HIV-1 latency.
Collapse
Affiliation(s)
- Laureano de la Vega
- Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Facultad de Medicina, Avda de Menéndez Pidal s/n, 14004, Córdoba, Spain
| | | | | | | | | | | |
Collapse
|
29
|
Pingle SC, Jajoo S, Mukherjea D, Sniderhan LF, Jhaveri KA, Marcuzzi A, Rybak LP, Maggirwar SB, Ramkumar V. Activation of the Adenosine A1Receptor Inhibits HIV-1 Tat-Induced Apoptosis by Reducing Nuclear Factor-κB Activation and Inducible Nitric-Oxide Synthase. Mol Pharmacol 2007; 72:856-67. [PMID: 17609415 DOI: 10.1124/mol.106.031427] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human immunodeficiency virus dementia (HIV-D) is a nonfocal central nervous system manifestation characterized by cognitive, behavioral, and motor abnormalities. The pathophysiology of neuronal damage in HIV-D includes a direct toxic effect of viral proteins on neuronal cells and an indirect effect caused by the release of inflammatory mediators and neurotoxins by activated macrophages/microglia and astrocytes, culminating into neuronal apoptosis. Previous studies have documented that the nucleoside adenosine mediates neuroprotection by activating adenosine A(1) receptor subtype (A(1)AR) linked to suppression of neuronal excitability. In this study, we show that A(1)AR activation protects against HIV-1 Tat-induced toxicity in primary cultures of rat cerebellar granule neurons and in rat pheochromocytoma (PC12) cell. In PC12 cells, HIV-1 Tat increased [Ca(2+)](i) levels, release of nitric oxide (NO), and expression of inducible nitric-oxide synthase (iNOS) and A(1)AR. Activation of A(1)AR suppressed Tat-mediated increases in [Ca(2+)](i) and NO. Furthermore, A(1)AR agonists inhibited iNOS expression in a nuclear factor-kappaB (NF-kappaB)-dependent manner. It is noteworthy that activation of the A(1)AR or inhibition of NOS protected against Tat-induced apoptosis in PC12 cells and cerebellar granule cells. Moreover, activation of the A(1)AR-inhibited Tat-induced increases in the levels of proapoptotic proteins Bax and caspase-3. Taken together, our results demonstrate that the A(1)AR protects against HIV-1 toxicity by inhibiting NF-kappaB, thereby reducing the expression of iNOS and NO radicals and neuronal apoptosis.
Collapse
Affiliation(s)
- Sandeep C Pingle
- Department of Pharmacology, Southern Illinois University School of Medicine, PO Box 19629, Springfield, IL 62794-9629, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Fonte C, Trousson A, Grenier J, Schumacher M, Massaad C. Opposite effects of CBP and p300 in glucocorticoid signaling in astrocytes. J Steroid Biochem Mol Biol 2007; 104:220-7. [PMID: 17475479 DOI: 10.1016/j.jsbmb.2007.03.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In the nervous system, glucocorticoid hormones play a major role during development, and they continue to affect functional and structural plasticity throughout life. Glucocorticoid actions are mediated by their cognate nuclear receptor, the glucocorticoid receptor (GR). The transcriptional activity of the GR is enhanced by the recruitment of one of the transcriptional coactivators of the p160 family (SRCs), which are a docking platform for secondary coactivators like CBP, or its close homologue p300. Here, we investigated the implication of CBP and p300 coactivators in glial cells of the central and peripheral nervous system, namely in primary cultures of astrocytes and in Schwann cells. We show that both coregulators behave differently in either cell type. CBP enhances GR transcriptional activation in astrocytes, and has no effect in Schwann cells, whereas p300 exerts an inhibitory effect in both glial cells. Studies with p300 deletion mutants show that the repressive capacity of p300 is related to its acetyltransferase activity. This work shows striking differences between CBP and p300 actions in astrocytes. Moreover, in astrocytes the opposite effects of CBP and p300 could lead to a balance in the transactivation potency of the GR, in order to fine tune the action of glucocorticoids.
Collapse
Affiliation(s)
- Cosima Fonte
- INSERM UMR788, University Paris-Sud (Paris XI), 80 rue du Général Leclerc, 94276 Le Kremlin-Bicêtre Cedex, France
| | | | | | | | | |
Collapse
|
31
|
Sharma A, Awasthi S, Harrod CK, Matlock EF, Khan S, Xu L, Chan S, Yang H, Thammavaram CK, Rasor RA, Burns DK, Skiest DJ, Van Lint C, Girard AM, McGee M, Monnat RJ, Harrod R. The Werner Syndrome Helicase Is a Cofactor for HIV-1 Long Terminal Repeat Transactivation and Retroviral Replication. J Biol Chem 2007; 282:12048-57. [PMID: 17317667 DOI: 10.1074/jbc.m608104200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Werner syndrome helicase (WRN) participates in DNA replication, double strand break repair, telomere maintenance, and p53 activation. Mutations of wrn cause Werner syndrome (WS), an autosomal recessive premature aging disorder associated with cancer predisposition, atherosclerosis, and other aging related symptoms. Here, we report that WRN is a novel cofactor for HIV-1 replication. Immortalized human WRN(-/-) WS fibroblasts, lacking a functional wrn gene, are impaired for basal and Tat-activated HIV-1 transcription. Overexpression of wild-type WRN transactivates the HIV-1 long terminal repeat (LTR) in the absence of Tat, and WRN cooperates with Tat to promote high-level LTR transactivation. Ectopic WRN induces HIV-1 p24(Gag) production and retroviral replication in HIV-1-infected H9(HIV-1IIIB) lymphocytes. A dominant-negative helicase-minus mutant, WRN(K577M), inhibits LTR transactivation and HIV-1 replication. Inhibition of endogenous WRN, through co-expression of WRN(K577M), diminishes recruitment of p300/CREB-binding protein-associated factor (PCAF) and positive transcription elongation factor b (P-TEFb) to Tat/transactivation response-RNA complexes, and immortalized WRN(-/-) WS fibroblasts exhibit comparable defects in recruitment of PCAF and P-TEFb to the HIV-1 LTR. Our results demonstrate that WRN is a novel cellular cofactor for HIV-1 replication and suggest that the WRN helicase participates in the recruitment of PCAF/P-TEFb-containing transcription complexes. WRN may be a plausible target for antiretroviral therapy.
Collapse
Affiliation(s)
- Anima Sharma
- Laboratory of Molecular Virology, Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275-0376, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Epie N, Ammosova T, Turner W, Nekhai S. Inhibition of PP2A by LIS1 increases HIV-1 gene expression. Retrovirology 2006; 3:65. [PMID: 17018134 PMCID: PMC1615876 DOI: 10.1186/1742-4690-3-65] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 10/02/2006] [Indexed: 01/29/2023] Open
Abstract
Background Lissencephaly is a severe brain malformation in part caused by mutations in the LIS1 gene. LIS1 interacts with microtubule-associated proteins, and enhances transport of microtubule fragments. Previously we showed that LIS1 interacts with HIV-1 Tat protein and that this interaction was mediated by WD40 domains of LIS1. In the present study, we analyze the effect of LIS1 on Tat-mediated transcription of HIV-1 LTR. Results Tat-mediated HIV-1 transcription was upregulated in 293 cells transfected with LIS1 expression vector. The WD5 but not the N-terminal domain of LIS1 increases Tat-dependent HIV-1 transcription. The effect of LIS1 was similar to the effect of okadaic acid, an inhibitor of protein phosphatase 2A (PP2A). We then analyzed the effect of LIS1 on the activity of PP2A in vitro. We show that LIS1 and its isolated WD5 domain but not the N-terminal domain of LIS1 blocks PP2A activity. Conclusion Our results show that inhibition of PP2A by LIS1 induces HIV-1 transcription. Our results also point to a possibility that LIS1 might function in the cells as a yet unrecognized regulatory subunit of PP2A.
Collapse
Affiliation(s)
- Nicolas Epie
- Center for Sickle Cell Disease, Howard University College of Medicine, 520 W Street N.W., Washington, DC 20059, USA
- Department of Microbiology, Howard University College of Medicine, 520 W Street N.W., Washington, DC 20059, USA
| | - Tatyana Ammosova
- Center for Sickle Cell Disease, Howard University College of Medicine, 520 W Street N.W., Washington, DC 20059, USA
| | - Willie Turner
- Department of Microbiology, Howard University College of Medicine, 520 W Street N.W., Washington, DC 20059, USA
| | - Sergei Nekhai
- Center for Sickle Cell Disease, Howard University College of Medicine, 520 W Street N.W., Washington, DC 20059, USA
- Department of Biochemistry and Molecular Biology, Howard University College of Medicine, 520 W Street N.W., Washington, DC 20059, USA
| |
Collapse
|
33
|
Alfonso P, Quetglas JI, Escribano JM, Alonso C. Protein pE120R of African swine fever virus is post-translationally acetylated as revealed by post-source decay MALDI mass spectrometry. Virus Genes 2006; 35:81-5. [PMID: 16964554 DOI: 10.1007/s11262-006-0015-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Accepted: 05/08/2006] [Indexed: 12/11/2022]
Abstract
Post-translational modification of proteins is a key regulatory event in many cellular processes. African swine fever virus (ASFV) is a large DNA virus that contains about 150 open reading frames (ORF) which encode for more than 150 polypeptides, most of them without assigned function. Two-dimensional gel electrophoresis (2DE) followed by Post-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (PSD-MALDI-MS) revealed that ASFV protein pE120R, essential for virus transport from assembly sites to plasma membranes, is acetylated at the N-terminal Ala residue during infection. To our knowledge, this is the first acetylated ASFV protein described and this modification might be relevant to ASFV life cycle since many viruses use the acetylation signaling pathway as a primary target for viral proteins after infection.
Collapse
Affiliation(s)
- Patricia Alfonso
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Ctra de la Coruña Km 7, 28040, Madrid, Spain
| | | | | | | |
Collapse
|
34
|
King JE, Eugenin EA, Buckner CM, Berman JW. HIV tat and neurotoxicity. Microbes Infect 2006; 8:1347-57. [PMID: 16697675 DOI: 10.1016/j.micinf.2005.11.014] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Accepted: 11/29/2005] [Indexed: 01/13/2023]
Abstract
HIV tat is the transactivator of HIV-1, supporting efficient viral replication by stabilizing the transcription of viral genes. Tat can be released from HIV-infected cells and alter several functions in uninfected cells. In the brain, tat induces neuronal dysfunction/toxicity, even though neurons cannot be directly infected with HIV, resulting in CNS pathology, such as the dementia and encephalitis associated with NeuroAIDS. This review discusses the most recent data addressing tat-induced neurotoxicity and integrates these new findings in the context of NeuroAIDS.
Collapse
Affiliation(s)
- J E King
- Department of Pathology, F727, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | | | | | | |
Collapse
|
35
|
Saydam O, Steiner F, Vogt B, Schwyzer M. Host cell targets of immediate-early protein BICP22 of bovine herpesvirus 1. Vet Microbiol 2005; 113:185-92. [PMID: 16352405 DOI: 10.1016/j.vetmic.2005.11.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The immediate-early (IE) protein BICP22 of bovine herpesvirus 1 (BHV-1) acts as transrepressor protein on viral promoters of different kinetic classes. In the present work, we looked for host cell targets of BICP22 using a yeast two-hybrid system and identified seven candidates: (1) JIK, a serine/threonine kinase of the sterile 20 protein (STE20) family that inhibits stress-related pathways; (2) cAMP response element binding protein-like 2 (CREBL2), which in its bZip domain shares homology with CREB, modulating transcription of cAMP responsive genes; (3) DNA-dependent ATPase and helicase (ATRX), a protein of the SNF2 family altering nucleosome structure; (4) scaffold attachment factor B (SAF-B), which helps to organize chromatin into topologically separated loops; (5) peptidylglycine alpha-amidating monooxygenase COOH-terminal interactor protein 1 (PAMCIP1), involved in regulation of the secretory pathway in the perinuclear area; (6) zinc finger protein (ZNF38) found in proliferating cells and possibly associated with meiosis in male and female gametogenesis; (7) FLJ22709, hypothetical protein conserved among various species, containing an occludin/ELL domain. To confirm some of the interactions by confocal fluorescence microscopy, BICP22 was tagged with red fluorescent protein in an amplicon, and selected target sequences were tagged with green fluorescent protein in plasmid expression vectors. Upon amplicon transduction of Vero cells and plasmid transfection, CREBL2 and ZNF38 both colocalized with BICP22 in distinct nuclear domains.
Collapse
Affiliation(s)
- Okay Saydam
- Faculty of Veterinary Medicine, Institute of Virology, University of Zurich, Winterthurerstrasse 266A, CH-8057 Zurich, Switzerland
| | | | | | | |
Collapse
|
36
|
Saunders M, Eldeen MB, Del Valle L, Reiss K, Peruzzi F, Mameli G, Gelman BB, Khalili K, Amini S, Sawaya BE. p73 modulates HIV-1 Tat transcriptional and apoptotic activities in human astrocytes. Apoptosis 2005; 10:1419-31. [PMID: 16235026 DOI: 10.1007/s10495-005-2467-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
HIV-1 Tat is a potent transcriptional activator of the viral promoter with the ability to modulate a number of cellular regulatory circuits including apoptosis. Tat exerts its effects through interaction with viral as well as cellular proteins. Here, we studied the influence of p73, a protein that is implicated in apoptosis and cell cycle control, on Tat apoptotic function in the central nervous system. We recently demonstrated the ability of Tat to associate with p73, and that this association modulates Tat transcriptional activity (Amini et al., Mol Cell Biol 2005; 18: 8126-8138). We demonstrated that p73 interferes with Tat-mediated apoptosis by preventing the up-regulation of Bax and down-regulation of Bcl-2 proteins in astrocytes. Thus, the interplay between Tat and p73 may affect Tat contribution to apoptotic events in the brain, limiting its involvement in the neuropathology often observed in the brains of HIV-1 patients.
Collapse
Affiliation(s)
- M Saunders
- Department of Neuroscience & Center for Neurovirology, Temple University, 1900 North 12th Street, 015-96, Philadelphia, PA 19122, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Amini S, Mameli G, Del Valle L, Skowronska A, Reiss K, Gelman BB, White MK, Khalili K, Sawaya BE. p73 Interacts with human immunodeficiency virus type 1 Tat in astrocytic cells and prevents its acetylation on lysine 28. Mol Cell Biol 2005; 25:8126-38. [PMID: 16135803 PMCID: PMC1234304 DOI: 10.1128/mcb.25.18.8126-8138.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat is a potent transcriptional activator of the HIV-1 promoter and also has the ability to modulate a number of cellular regulatory circuits including apoptosis. Tat exerts its effects through interaction with viral as well as cellular proteins. Here, we studied the influence of p73, a protein that is implicated in apoptosis and cell cycle control, on Tat functions in the central nervous system. Protein interaction studies using immunoprecipitation followed by Western blot and glutathione S-transferase pull-down assays demonstrated the association of Tat with p73. Tat bound to the N-terminal region of p73 spanning amino acids 1 to 120, and this interaction required the cysteine-rich domain (amino acids 30 to 40) of Tat. Association of p73 with Tat prevented the acetylation of Tat on lysine 28 by PCAF. Functional studies including RNA interference showed that p73 inhibited Tat stimulation of the HIV-1 promoter. Furthermore, p73 prevented the interaction of Tat with cyclin T1 in vitro but not in vivo. These findings suggest possible new therapeutic approaches, using p73, for Tat-mediated AIDS pathogenesis.
Collapse
Affiliation(s)
- Shohreh Amini
- Center for Neurovirology and Cancer Biology, Temple University, 1900 North 12th Street, Philadelphia, PA 19122, USA
| | | | | | | | | | | | | | | | | |
Collapse
|