The Presence of HIV-1 Tat Protein Second Exon Delays Fas Protein-mediated Apoptosis in CD4+ T Lymphocytes

Background: HIV-infected T cells are quite resistant to apoptosis. Results: Intracellular expression of HIV-1 Tat in T cells stabilized the mitochondrial membrane and reduced caspase activation mainly through NF-κB activation. Conclusion: Intracellular Tat induced resistance to FasL-mediated apoptosis in T cells mainly through the second exon. Significance: Tat-mediated protection against apoptosis may be a mechanism for HIV-1 persistence. HIV-1 replication is efficiently controlled by the regulator protein Tat (101 amino acids) and codified by two exons, although the first exon (1–72 amino acids) is sufficient for this process. Tat can be released to the extracellular medium, acting as a soluble pro-apoptotic factor in neighboring cells. However, HIV-1-infected CD4+ T lymphocytes show a higher resistance to apoptosis. We observed that the intracellular expression of Tat delayed FasL-mediated apoptosis in both peripheral blood lymphocytes and Jurkat cells, as it is an essential pathway to control T cell homeostasis during immune activation. Jurkat-Tat cells showed impairment in the activation of caspase-8, deficient release of mitochondrial cytochrome c, and delayed activation of both caspase-9 and -3. This protection was due to a profound deregulation of proteins that stabilized the mitochondrial membrane integrity, such as heat shock proteins, prohibitin, or nucleophosmin, as well as to the up-regulation of NF-κB-dependent anti-apoptotic proteins, such as BCL2, c-FLIPS, XIAP, and C-IAP2. These effects were observed in Jurkat expressing full-length Tat (Jurkat-Tat101) but not in Jurkat expressing the first exon of Tat (Jurkat-Tat72), proving that the second exon, and particularly the NF-κB-related motif ESKKKVE, was necessary for Tat-mediated protection against FasL apoptosis. Accordingly, the protection exerted by Tat was independent of its function as a regulator of both viral transcription and elongation. Moreover, these data proved that HIV-1 could have developed strategies to delay FasL-mediated apoptosis in infected CD4+ T lymphocytes through the expression of Tat, thus favoring the persistent replication of HIV-1 in infected T cells.

[1]  D. Tulasne,et al.  Caspase cleavage of viral proteins, another way for viruses to make the best of apoptosis , 2012, Cell Death and Disease.

[2]  H. Steen,et al.  Mass Spectrometry-Based Proteomics for Translational Research: A Technical Overview , 2012, The Yale journal of biology and medicine.

[3]  William J. Kaiser,et al.  Viral infection and the evolution of caspase 8-regulated apoptotic and necrotic death pathways , 2011, Nature Reviews Immunology.

[4]  I. Chowdhury,et al.  Prohibitin (PHB) acts as a potent survival factor against ceramide induced apoptosis in rat granulosa cells. , 2011, Life sciences.

[5]  T. Kundu,et al.  HIV-1 infection induces acetylation of NPM1 that facilitates Tat localization and enhances viral transactivation. , 2011, Journal of molecular biology.

[6]  Peter Scheurich,et al.  TNFR1‐induced activation of the classical NF‐κB pathway , 2011, The FEBS journal.

[7]  Donna D. Zhang,et al.  The Type III Histone Deacetylase Sirt1 Protein Suppresses p300-mediated Histone H3 Lysine 56 Acetylation at Bclaf1 Promoter to Inhibit T Cell Activation* , 2011, The Journal of Biological Chemistry.

[8]  H. Ahsan,et al.  Role of Bcl-2 family proteins and caspases in the regulation of apoptosis , 2011, Molecular and Cellular Biochemistry.

[9]  Damian Szklarczyk,et al.  The STRING database in 2011: functional interaction networks of proteins, globally integrated and scored , 2010, Nucleic Acids Res..

[10]  M. Lindström.  NPM1/B23: A Multifunctional Chaperone in Ribosome Biogenesis and Chromatin Remodeling , 2010, Biochemistry research international.

[11]  J. McPherson,et al.  In Search of a Function for BCLAF1 , 2010, TheScientificWorldJournal.

[12]  C. Obuse,et al.  Nucleosome Formation Activity of Human Somatic Nuclear Autoantigenic Sperm Protein (sNASP)* , 2010, The Journal of Biological Chemistry.

[13]  A. Dopazo,et al.  Modifications in host cell cytoskeleton structure and function mediated by intracellular HIV-1 Tat protein are greatly dependent on the second coding exon , 2010, Nucleic acids research.

[14]  J. D. Robertson,et al.  Caspase-9 Activation by the Apoptosome Is Not Required for Fas-mediated Apoptosis in Type II Jurkat Cells* , 2009, The Journal of Biological Chemistry.

[15]  M. Mann,et al.  Lysine Acetylation Targets Protein Complexes and Co-Regulates Major Cellular Functions , 2009, Science.

[16]  M. O'Rand,et al.  Analysis of gene expression profiles in HeLa cells in response to overexpression or siRNA-mediated depletion of NASP , 2009, Reproductive biology and endocrinology : RB&E.

[17]  D. S. St. Clair,et al.  Nucleophosmin Blocks Mitochondrial Localization of p53 and Apoptosis* , 2009, The Journal of Biological Chemistry.

[18]  M. Olson,et al.  Nucleolar protein B23 has molecular chaperone activities , 2008, Protein science : a publication of the Protein Society.

[19]  M. Caputi,et al.  Role of Cellular RNA Processing Factors in Human Immunodeficiency Virus Type 1 mRNA Metabolism, Replication, and Infectivity , 2008, Journal of Virology.

[20]  Yigong Shi,et al.  FLIP and the death effector domain family , 2008, Oncogene.

[21]  J. Ausió,et al.  sNASP, a histone H1-specific eukaryotic chaperone dimer that facilitates chromatin assembly. , 2008, Biophysical journal.

[22]  D. Green,et al.  How do BCL-2 proteins induce mitochondrial outer membrane permeabilization? , 2008, Trends in cell biology.

[23]  C. Van Lint,et al.  NF‐κB‐dependent control of HIV‐1 transcription by the second coding exon of Tat in T cells , 2008, Journal of leukocyte biology.

[24]  G. Rabinovich,et al.  Apoptosis resistance in HIV-1 persistently-infected cells is independent of active viral replication and involves modulation of the apoptotic mitochondrial pathway , 2008, Retrovirology.

[25]  A. Safa,et al.  Cellular FLICE-like inhibitory protein (C-FLIP): a novel target for cancer therapy. , 2008, Current cancer drug targets.

[26]  F. Khuri,et al.  Down-regulation of 14-3-3ζ suppresses anchorage-independent growth of lung cancer cells through anoikis activation , 2008, Proceedings of the National Academy of Sciences.

[27]  G. Salvesen,et al.  The apoptosome: signalling platform of cell death , 2007, Nature Reviews Molecular Cell Biology.

[28]  J. Mcculloch,et al.  Nucleophosmin is a novel Bax chaperone that regulates apoptotic cell death , 2007, Oncogene.

[29]  John Calvin Reed,et al.  The FLIP-Side of Fas Signaling , 2006, Clinical Cancer Research.

[30]  M. Biard-Piechaczyk,et al.  Mechanisms of CD4 T-cell depletion triggered by HIV-1 viral proteins. , 2006, AIDS reviews.

[31]  J. López,et al.  Modifications in the human T cell proteome induced by intracellular HIV‐1 Tat protein expression , 2006, Proteomics.

[32]  H. Moon,et al.  Role of HIV Vpr as a regulator of apoptosis and an effector on bystander cells. , 2006, Molecules and cells.

[33]  Xiaodong Wang,et al.  Formation of apoptosome is initiated by cytochrome c-induced dATP hydrolysis and subsequent nucleotide exchange on Apaf-1. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[34]  S. Petrini,et al.  A review of HIV‐1 Tat protein biological effects , 2005, Cell biochemistry and function.

[35]  G. Zauli,et al.  HIV‐1 Tat protein concomitantly down‐regulates apical caspase‐10 and up‐regulates c‐FLIP in lymphoid T cells: A potential molecular mechanism to escape TRAIL cytotoxicity , 2005, Journal of cellular physiology.

[36]  P. Reiss,et al.  Infection with HIV-1 induces a decrease in mtDNA. , 2005, The Journal of infectious diseases.

[37]  P. Krammer,et al.  c-FLIPR, a New Regulator of Death Receptor-induced Apoptosis* , 2005, Journal of Biological Chemistry.

[38]  M. Gougeon.  To kill or be killed: how HIV exhausts the immune system , 2005, Cell Death and Differentiation.

[39]  D. Newmeyer,et al.  Mitochondrial Release of Pro-apoptotic Proteins , 2005, Journal of Biological Chemistry.

[40]  F. Mammano,et al.  A novel mechanism for HIV1-mediated bystander CD4+ T-cell death: neighboring dying cells drive the capacity of HIV1 to kill noncycling primary CD4+ T cells , 2004, Cell Death and Differentiation.

[41]  B. Dörken,et al.  Characterization of apoptosis-induced Mcm3 and Cdc6 cleavage reveals a proapoptotic effect for one Mcm3 fragment , 2004, Cell Death and Differentiation.

[42]  G. Kroemer,et al.  Mitochondrial membrane permeabilization by HIV-1 Vpr. , 2004, Mitochondrion.

[43]  Sun-Mi Park,et al.  Receptor interacting protein is ubiquitinated by cellular inhibitor of apoptosis proteins (c‐IAP1 and c‐IAP2) in vitro , 2004, FEBS letters.

[44]  P. Krammer,et al.  Resistance of Short Term Activated T Cells to CD95-Mediated Apoptosis Correlates with De Novo Protein Synthesis of c-FLIPshort1 , 2004, The Journal of Immunology.

[45]  K. Ganesh,et al.  HIV-1 Tat directly binds to NFkappaB enhancer sequence: role in viral and cellular gene expression. , 2004, Nucleic acids research.

[46]  Z. Klase,et al.  An in Vivo Replication-important Function in the Second Coding Exon of Tat Is Constrained against Mutation despite Cytotoxic T Lymphocyte Selection* , 2003, Journal of Biological Chemistry.

[47]  Jerry M. Adams,et al.  Ways of dying: multiple pathways to apoptosis. , 2003, Genes & development.

[48]  Ping H Wang,et al.  Hsp10 and Hsp60 modulate Bcl-2 family and mitochondria apoptosis signaling induced by doxorubicin in cardiac muscle cells. , 2003, Journal of molecular and cellular cardiology.

[49]  J. Alimonti,et al.  Mechanisms of CD4+ T lymphocyte cell death in human immunodeficiency virus infection and AIDS. , 2003, The Journal of general virology.

[50]  M. Peter,et al.  The CD95 type I/type II model. , 2003, Seminars in immunology.

[51]  A. Badley,et al.  Vpr R77Q is associated with long-term nonprogressive HIV infection and impaired induction of apoptosis. , 2003, The Journal of clinical investigation.

[52]  G. Kroemer,et al.  The mitochondriotoxic domain of Vpr determines HIV-1 virulence. , 2003, The Journal of clinical investigation.

[53]  K. Caldwell,et al.  Role for NudC, a dynein-associated nuclear movement protein, in mitosis and cytokinesis , 2003, Journal of Cell Science.

[54]  Kuan-Teh Jeang,et al.  Tat and Trans-activation-responsive (TAR) RNA-independent Induction of HIV-1 Long Terminal Repeat by Human and Murine Cyclin T1 Requires Sp1* , 2003, The Journal of Biological Chemistry.

[55]  S. Srinivasula,et al.  Mechanism of XIAP-mediated inhibition of caspase-9. , 2003, Molecular cell.

[56]  C. Briand,et al.  Insights into the regulatory mechanism for caspase-8 activation. , 2003, Molecular cell.

[57]  H. Itoh,et al.  Mammalian HSP60 is quickly sorted into the mitochondria under conditions of dehydration. , 2002, European journal of biochemistry.

[58]  E. White,et al.  Viral homologs of BCL-2: role of apoptosis in the regulation of virus infection. , 2002, Genes & development.

[59]  Shekhar C Mande,et al.  Site-directed mutagenesis reveals a novel catalytic mechanism of Mycobacterium tuberculosis alkylhydroperoxidase C. , 2002, The Biochemical journal.

[60]  G. Barbanti-Brodano,et al.  Inhibition of HIV-1 Tat activity correlates with down-regulation of bcl-2 and results in reduction of angiogenesis and oncogenicity. , 2002, Virology.

[61]  D. Hancock,et al.  Identification of Novel Isoforms of the BH3 Domain Protein Bim Which Directly Activate Bax To Trigger Apoptosis , 2002, Molecular and Cellular Biology.

[62]  Michael Karin,et al.  NF-κB at the crossroads of life and death , 2002, Nature Immunology.

[63]  G. Salvesen,et al.  Reprieval from execution: the molecular basis of caspase inhibition. , 2002, Trends in biochemical sciences.

[64]  R. Fisher,et al.  Phosphorylation of the protein kinase C-theta activation loop and hydrophobic motif regulates its kinase activity, but only activation loop phosphorylation is critical to in vivo nuclear-factor-kappaB induction. , 2002, The Biochemical journal.

[65]  M. Just,et al.  Interdependence of Nonoverlapping Cortical Systems in Dual Cognitive Tasks , 2001, NeuroImage.

[66]  P. Krammer,et al.  Cellular FLICE-inhibitory Protein Splice Variants Inhibit Different Steps of Caspase-8 Activation at the CD95 Death-inducing Signaling Complex* , 2001, The Journal of Biological Chemistry.

[67]  I. Hewlett,et al.  Identification of a Potential HIV-Induced Source of Bystander-Mediated Apoptosis in T Cells: Upregulation of TRAIL in Primary Human Macrophages by HIV-1 Tat , 2001, Journal of Biomedical Science.

[68]  I. Hewlett,et al.  Identification of a potential HIV-induced source of bystander-mediated apoptosis in T cells: upregulation of trail in primary human macrophages by HIV-1 tat. , 2001, Journal of biomedical science.

[69]  G. Zachos,et al.  Herpes Simplex Virus Type 1 Blocks the Apoptotic Host Cell Defense Mechanisms That Target Bcl-2 and Manipulates Activation of p38 Mitogen-Activated Protein Kinase To Improve Viral Replication , 2001, Journal of Virology.

[70]  Young-Gyu Ko,et al.  Heat Shock Protein 70 Inhibits Apoptosis Downstream of Cytochrome c Release and Upstream of Caspase-3 Activation* , 2000, The Journal of Biological Chemistry.

[71]  G. Kroemer,et al.  The HIV-1 Viral Protein R Induces Apoptosis via a Direct Effect on the Mitochondrial Permeability Transition Pore , 2000, The Journal of experimental medicine.

[72]  Jean-Claude Martinou,et al.  Bid-induced Conformational Change of Bax Is Responsible for Mitochondrial Cytochrome c Release during Apoptosis , 1999, The Journal of cell biology.

[73]  M. Fresno,et al.  Expression of IκBα in the nucleus of human peripheral blood T lymphocytes , 1999, Oncogene.

[74]  F. Barré-Sinoussi,et al.  Human Immunodeficiency Virus Induces a Dual Regulation of Bcl-2, Resulting in Persistent Infection of CD4+ T- or Monocytic Cell Lines , 1998, Journal of Virology.

[75]  C. Y. Wang,et al.  NF-kappaB antiapoptosis: induction of TRAF1 and TRAF2 and c-IAP1 and c-IAP2 to suppress caspase-8 activation. , 1998, Science.

[76]  P. Golstein,et al.  Cell Death in Us and Others , 1998, Science.

[77]  Xiaodong Wang,et al.  Bid, a Bcl2 Interacting Protein, Mediates Cytochrome c Release from Mitochondria in Response to Activation of Cell Surface Death Receptors , 1998, Cell.

[78]  Junying Yuan,et al.  Cleavage of BID by Caspase 8 Mediates the Mitochondrial Damage in the Fas Pathway of Apoptosis , 1998, Cell.

[79]  É. Cohen,et al.  Vpr Stimulates Viral Expression and Induces Cell Killing in Human Immunodeficiency Virus Type 1-Infected Dividing Jurkat T Cells , 1998, Journal of Virology.

[80]  Melina V Jones,et al.  Intraventricular Injection of Human Immunodeficiency Virus Type 1 (HIV-1) Tat Protein Causes Inflammation, Gliosis, Apoptosis, and Ventricular Enlargement , 1998, Journal of neuropathology and experimental neurology.

[81]  H. Xiao,et al.  Interaction of the second coding exon of Tat with human EF-1 delta delineates a mechanism for HIV-1-mediated shut-off of host mRNA translation. , 1998, Biochemical and biophysical research communications.

[82]  M. Peter,et al.  Two CD95 (APO‐1/Fas) signaling pathways , 1998, The EMBO journal.

[83]  P. Matarrese,et al.  The HIV-1 vpr Protein Acts as a Negative Regulator of Apoptosis in a Human Lymphoblastoid T Cell Line: Possible Implications for the Pathogenesis of AIDS , 1998, The Journal of experimental medicine.

[84]  P. Nicotera,et al.  Selective proteolysis of the nuclear replication factor MCM3 in apoptosis. , 1998, Experimental cell research.

[85]  S. Srinivasula,et al.  Cytochrome c and dATP-Dependent Formation of Apaf-1/Caspase-9 Complex Initiates an Apoptotic Protease Cascade , 1997, Cell.

[86]  M. Previati,et al.  Extracellular HIV‐1 Tat protein activates phosphatidylinositol 3‐ and Akt/PKB kinases in CD4+ T lymphoblastoid Jurkat cells , 1997, European journal of immunology.

[87]  G. Morris,et al.  Distinct transcriptional pathways of TAR-dependent and TAR-independent human immunodeficiency virus type-1 transactivation by Tat. , 1997, Virology.

[88]  Margot Thome,et al.  Inhibition of death receptor signals by cellular FLIP , 1997, Nature.

[89]  I. Chen,et al.  Human immunodeficiency virus type 1 Vpr induces apoptosis following cell cycle arrest , 1997, Journal of virology.

[90]  Guy S. Salvesen,et al.  X-linked IAP is a direct inhibitor of cell-death proteases , 1997, Nature.

[91]  C. Van Lint,et al.  Immune Hyperactivation of HIV-1-Infected T Cells Mediated by Tat and the CD28 Pathway , 1997, Science.

[92]  E. Verdin,et al.  Dual role of HIV Tat in regulation of apoptosis in T cells. , 1997, Journal of immunology.

[93]  M. Negrini,et al.  The human immunodeficiency virus type-1 Tat protein upregulates Bcl-2 gene expression in Jurkat T-cell lines and primary peripheral blood mononuclear cells. , 1995, Blood.

[94]  M. Schechter,et al.  CD4+ blood lymphocytes are rapidly killed in vitro by contact with autologous human immunodeficiency virus-infected cells. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[95]  J. Yates,et al.  Method to correlate tandem mass spectra of modified peptides to amino acid sequences in the protein database. , 1995, Analytical chemistry.

[96]  K. Schulze-Osthoff,et al.  HIV‐1 Tat potentiates TNF‐induced NF‐kappa B activation and cytotoxicity by altering the cellular redox state. , 1995, The EMBO journal.

[97]  T. Curiel,et al.  Apoptosis occurs predominantly in bystander cells and not in productively infected cells of HIV- and SIV-infected lymph nodes , 1995, Nature Medicine.

[98]  S. Capitani,et al.  Tat‐expressing Jurkat cells show an increased resistance to different apoptotic stimuli, including acute human immunodeficiency virus‐type 1 (HIV ‐1) infection , 1995, British journal of haematology.

[99]  W. Blattner,et al.  Temporal analysis of the antibody response to HIV envelope protein in HIV-infected laboratory workers. , 1994, The Journal of clinical investigation.

[100]  N. Jenkins,et al.  Generalized lymphoproliferative disease in mice, caused by a point mutation in the fas ligand , 1994, Cell.

[101]  C. Franceschi,et al.  A new method for the cytofluorimetric analysis of mitochondrial membrane potential using the J-aggregate forming lipophilic cation 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide (JC-1). , 1993, Biochemical and biophysical research communications.

[102]  M. Diaz-Meco,et al.  Phosphatidylcholine hydrolysis activates NF-kappa B and increases human immunodeficiency virus replication in human monocytes and T lymphocytes , 1993, Journal of virology.

[103]  S. J. Clark,et al.  High levels of HIV-1 in plasma during all stages of infection determined by competitive PCR. , 1993, Science.

[104]  D. Derse,et al.  Identification of lentivirus tat functional domains through generation of equine infectious anemia virus/human immunodeficiency virus type 1 tat gene chimeras , 1991, Journal of virology.

[105]  B. Berkhout,et al.  trans activation of human immunodeficiency virus type 1 is sequence specific for both the single-stranded bulge and loop of the trans-acting-responsive hairpin: a quantitative analysis , 1989, Journal of virology.

[106]  J. Levy.  Pathogenesis of human immunodeficiency virus infection , 1989, Microbiological reviews.

[107]  E. Tan,et al.  Proliferating cell nuclear antigen (PCNA)/cyclin in activated human T lymphocytes. , 1987, Journal of immunology.

[108]  H. Gendelman,et al.  Production of acquired immunodeficiency syndrome-associated retrovirus in human and nonhuman cells transfected with an infectious molecular clone , 1986, Journal of virology.

[109]  Arthur Weiss,et al.  The role of T3 surface molecules in the activation of human T cells: a two-stimulus requirement for IL 2 production reflects events occurring at a pre-translational level. , 1984, Journal of immunology.

[110]  A. Strasser,et al.  The essential role of evasion from cell death in cancer. , 2011, Advances in cancer research.

[111]  Ling Yan,et al.  Phosphatases and regulation of cell death. , 2008, Methods in enzymology.

[112]  X. Yao,et al.  Apoptosis of rat granulosa cells after staurosporine and serum withdrawal is suppressed by adenovirus-directed overexpression of prohibitin. , 2007, Endocrinology.

[113]  A. Gatignol,et al.  HIV-1 TAR RNA: the target of molecular interactions between the virus and its host. , 2005, Current HIV research.

[114]  G M Cohen,et al.  XIAP inhibition of caspase-3 preserves its association with the Apaf-1 apoptosome and prevents CD95- and Bax-induced apoptosis , 2002, Cell Death and Differentiation.

[115]  K. Jeang,et al.  Tat as a transcriptional activator and a potential therapeutic target for HIV-1. , 2000, Advances in pharmacology.