Jay Rappaport

Publications of Jay Rappaport

• CSF-1R Up-regulation Is Associated with Response to Pharmacotherapy Targeting Tyrosine Kinase Activity in AML Cell Lines.

  Authors: Michael Kogan, Tracy Fischer-Smith, Rafal Kaminsky, Gabrielle Lehmicke, Jay Rappaport

  Anticancer research. 03/2012; 32(3):893-9.

  The oncogenic potential of colony stimulating factor 1 receptor (CSF-1R) has been well described, while its relevance for human acute myelogenous leukemia (AML) is still undetermined. In a recentThe oncogenic potential of colony stimulating factor 1 receptor (CSF-1R) has been well described, while its relevance for human acute myelogenous leukemia (AML) is still undetermined. In a recent clinical trial for AML, sunitinib was found to hold potential therapeutic benefit, however, the mechanism for this remains unknown. In this study, we treated three myeloid cell lines, Mono-Mac 1, THP-1, and U937, with sunitinib, and a small-molecule CSF-1R inhibitor (cFMS-I) to test the anticancer effect of such treatment. Mono-Mac 1 cells had inhibited proliferation and extracellular-signal regulated kinase activity as a result of CSF-1R inhibition and a dose-dependent increase in CSF-1R expression with both sunitinib and cFMS-I. Our results suggest potential for CSF-1R as an important target of sunitinib or other similar drugs. Future study of CSF-1R may produce more targeted therapeutic approaches and aid in the development of personalized medicine for AML.

• Macrophage Colony Stimulating Factor Regulation by Nuclear Factor Kappa B: A Relevant Pathway in Human Immunodeficiency Virus Type 1 Infected Macrophages.

  Authors: Michael Kogan, Valerie Haine, Yuxong Ke, Brian Wigdahl, Tracy Fischer-Smith, Jay Rappaport

  DNA and cell biology. 09/2011;

  Macrophage colony stimulating factor (M-CSF) is a cytokine that promotes monocyte differentiation and survival. When overexpressed, M-CSF contributes to pathology in a wide variety of diseases,Macrophage colony stimulating factor (M-CSF) is a cytokine that promotes monocyte differentiation and survival. When overexpressed, M-CSF contributes to pathology in a wide variety of diseases, including osteoporosis, obesity, certain human cancers, and in human immunodeficiency virus type 1 (HIV-1) infection, particularly with respect to monocyte/macrophage infection and the development of HIV-1 associated central nervous system disorders. In this study, our aim was to expand the current knowledge of M-CSF regulation, focusing on nuclear factor kappa B (NF-κB), a transcription factor playing a prominent role during inflammation and HIV-1 infection. Our results suggest that tumor necrosis factor alpha (TNF-α) promotes M-CSF secretion in primary macrophages and activates the -1310/+48 bp M-CSF promoter in Mono-Mac 1 cells. Inhibitors of the NF-κB pathway diminish this response. We identified four putative NF-κB and four CCAAT-enhancer-binding protein beta binding sites within the M-CSF promoter. Our findings, using promoter constructs mutated at individual NF-κB sites within the M-CSF promoter region, suggest that these sites are redundant with respect to NF-κB regulation. TNF-α treatment promoted NF-κB p65 binding to the M-CSF promoter in phorbol 12-myristate 13-acetate (PMA) treated U937 cells chronically infected with HIV-1 (U1 cells), but not in PMA treated uninfected U937 cells, suggesting that the presence of HIV-1 increases the NF-κB response. In conclusion, our findings demonstrate that NF-κB induces M-CSF expression on a promoter level via multiple functional NF-κB binding sites and that this pathway is likely relevant in HIV-1 infection of macrophages.

• Role of C/EBP-β, p38 MAPK, and MKK6 in IL-1β-mediated C3 gene regulation in astrocytes.

  Authors: Jeffrey Maranto, Jay Rappaport, Prasun K Datta

  Journal of cellular biochemistry. 02/2011; 112(4):1168-75.

  Complement component C3, the central player in the complement cascade and the pro-inflammatory cytokine IL-1β is expressed by activated glial cells and may contribute to neurodegeneration. This studyComplement component C3, the central player in the complement cascade and the pro-inflammatory cytokine IL-1β is expressed by activated glial cells and may contribute to neurodegeneration. This study examines the regulation of the expression of C3 by IL-1β in astroglial cells focusing on the role of the upstream kinase MKK6, p38-α MAPK, and C/EBP-β isoforms (LAP1, LAP2, or LIP) in astroglial cells. Activation of human astroglial cell line, U373 with IL-1β, led to the induction of C3 mRNA and protein expression as determined by real-time RT-PCR and Western blot analysis, respectively. This induction was suppressed by the pharmacological inhibitor of p38 MAPK (i.e., SB202190-HCl), suggesting the involvement of p38 MAPK in C3 gene expression. IL-1β also induced C3 promoter activity in U373 cells in a MAP kinase- and C/EBP-β-dependent manner. Cotransfection of C3 luciferase reporter construct with constitutively active form of the upstream kinase in the MAP kinase cascade, that is, MKK6 (the immediate upstream activator of p38 kinase) resulted in marked stimulation of the promoter activity, whereas overexpression of a dominant negative forms of MKK6 and p38α MAPK inhibited C3 promoter activity. Furthermore, a mutant form of C/EBP-β, LAP(T235A) showed reduction in IL-1β-mediated C3 promoter activation. These results suggest that the p38α, MAPK, and MKK6 play prominent roles in IL-1β and C/EBP-β-mediated C3 gene expression in astrocytes.

• HIV-1 accessory protein Vpr: relevance in the pathogenesis of HIV and potential for therapeutic intervention.

  Authors: Michael Kogan, Jay Rappaport

  Retrovirology. 01/2011; 8:25.

  The HIV protein, Vpr, is a multifunctional accessory protein critical for efficient viral infection of target CD4+ T cells and macrophages. Vpr is incorporated into virions and functions to transportThe HIV protein, Vpr, is a multifunctional accessory protein critical for efficient viral infection of target CD4+ T cells and macrophages. Vpr is incorporated into virions and functions to transport the preintegration complex into the nucleus where the process of viral integration into the host genome is completed. This action is particularly important in macrophages, which as a result of their terminal differentiation and non-proliferative status, would be otherwise more refractory to HIV infection. Vpr has several other critical functions including activation of HIV-1 LTR transcription, cell-cycle arrest due to DCAF-1 binding, and both direct and indirect contributions to T-cell dysfunction. The interactions of Vpr with molecular pathways in the context of macrophages, on the other hand, support accumulation of a persistent reservoir of HIV infection in cells of the myeloid lineage. The role of Vpr in the virus life cycle, as well as its effects on immune cells, appears to play an important role in the immune pathogenesis of AIDS and the development of HIV induced end-organ disease. In view of the pivotal functions of Vpr in virus infection, replication, and persistence of infection, this protein represents an attractive target for therapeutic intervention.

• Activation of HIV-1 LTR by Rad51 in microglial cells.

  Authors: Inna Rom, Armine Darbinyan, Martyn K White, Jay Rappaport, Bassel E Sawaya, Shohreh Amini, Kamel Khalili

  Cell cycle (Georgetown, Tex.). 09/2010; 9(18):3715-22.

  Infection with HIV-1 induces a variety of biological alterations to the host that are beneficial to the life cycle of the virus but may have adverse effects on the host cell. Here we demonstrate thatInfection with HIV-1 induces a variety of biological alterations to the host that are beneficial to the life cycle of the virus but may have adverse effects on the host cell. Here we demonstrate that expression of Rad51, a major component of the homologous recombination-directed DNA repair (HRR) pathway, is induced upon HIV-1 infection of microglial cells. Activation of Rad51 expression positively impacts on HIV-1 LTR transcription through a region of the viral promoter known for binding the inducible transcription factor NFκB. Rad51 showed the ability to form a complex with the p65 subunit of NFκB and regulate the level of p65 interaction with LTR DNA encompassing the κB motif. This study provides evidence for reciprocal interaction of HIV-1 and a host DNA repair protein that impacts on expression of the viral genome. These results also point to the ability of HIV-1 to recruit proteins involved in DNA repair that are necessary for retroviral DNA integration, efficient replication and prevention of viral-induced cell death.

• SMAD Proteins of Oligodendroglial Cells Regulate Transcription of JC Viral Early and Late Genes Coordinately with the Tat Protein of Human Immunodeficiency Virus Type I.

  Authors: Michelle R. Stettner, Jonas A Nance, Clayton A. Wright, Yayoi Kinoshita, Woong-Ki Kim, Susan Morgello, Jay Rappaport, Kamel Khalili, Jennifer Gordon, Edward M Johnson

  The Journal of general virology. 05/2009;

  SummaryJC virus (JCV) is the etiologic agent of progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease of the brain in AIDS. Although immunosuppression is involved inSummaryJC virus (JCV) is the etiologic agent of progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease of the brain in AIDS. Although immunosuppression is involved in infection of the brain by JCV, a direct influence of human immunodeficiency virus type I (HIV-1) has also been established. The Tat protein of HIV-1 has been implicated in activation of the cytokine, TGF-beta, in HIV-1-infected cells and in stimulating JCV gene transcription and DNA replication in oligodendroglia, the primary CNS cell type infected by JCV in PML. Here we demonstrate that Tat can cooperate with SMAD proteins, the intracellular effectors of TGF-beta, at the JCV DNA control region (CR) to stimulate JCV gene transcription. Tat stimulates JCV early gene transcription in KG-1 oligodendroglial cells when either expressed via transfection or added exogenously. Using chromatin immunoprecipitation we show that exogenous Tat enhances binding of SMAD proteins 2, 3 and 4 and their binding partner Fast1 to the JCV CR in living cells. When SMADs 2, 3 and 4 are expressed together, Tat, expressed from plasmid pTat, stimulates transcription from both early and late gene promoters, the early promoter exhibiting stimulation of >100-fold. Tat, SMAD4 and polyoma JCV large T-antigen are all visualized in oligodendroglial cells at the border of an active PML lesion in the cerebral frontal lobe. These results reveal a positive reinforcement system in which the SMAD mediators of the TGF-beta system act cooperatively with Tat to stimulate JCV gene transcription.

• Activation of the oxidative stress pathway by HIV-1 Vpr leads to induction of hypoxia inducible factor 1 alpha expression.

  Authors: Satish L Deshmane, Ruma Mukerjee, Shongshan Fan, Luis Del Valle, Carine Michiels, Thersa Sweet, Inna Rom, Kamel Khalili, Jay Rappaport, Shohreh Amini, Bassel E Sawaya

  The Journal of biological chemistry. 03/2009;

  The detection of biomarkers of oxidative stress in brain tissue and cerebrospinal fluid of patients with HIV-1 dementia indicates the involvement of stress pathways in the neuropathogenesis of AIDS.The detection of biomarkers of oxidative stress in brain tissue and cerebrospinal fluid of patients with HIV-1 dementia indicates the involvement of stress pathways in the neuropathogenesis of AIDS. While the biological importance of oxidative stress on events involved in AIDS neuropathogenesis and the HIV-1 proteins responsible for oxidative stress remain to be elucidated, our results point to the activation of hypoxia-inducible factor 1 (HIF-1) upon HIV-1 infection and its elevation in brain cells of AIDS patients with dementia. HIF-1 is a transcription factor that is responsive to oxygen. Under hypoxic conditions, HIF-1a becomes stable and translocates to the nucleus where it dimerizes with ARNT and modulates gene transcription. Activation of HIF-1 can also be mediated by the HIV-1 accessory protein, Vpr. In addition, cellular events including reactive oxygen species (ROS) contribute to the induction of HIF-1a. Our results show that Vpr induces ROS by increasing H2O2 production, which can contribute to HIF-1a accumulation. Interestingly, increased levels of HIF-1a stimulated HIV-1 gene transcription through HIF-1 association with HIV-1 LTR DNA. These observations point to the existence of a positive feedback interplay between HIF-1a and Vpr and that, by inducing oxidative stress via activation of HIF-1, Vpr can induce HIV-1 gene expression and desregulate multiple host cellular pathways.

• Anti-cytokine therapeutics: history and update.

  Authors: Rojo A Ratsimandresy, Jay Rappaport, Jean-François Zagury

  Current pharmaceutical design. 02/2009; 15(17):1998-2025.

  Anti-cytokine therapy has promoted a revolution in the treatment of several inflammatory disorders during the past 10 years. Despite their medical and commercial success, they exhibit severalAnti-cytokine therapy has promoted a revolution in the treatment of several inflammatory disorders during the past 10 years. Despite their medical and commercial success, they exhibit several drawbacks: difficulties of production, excessive costs, and a few side-effects. A promising alternative to the passive infusion of monoclonal antibodies or soluble cytokine receptors is the use of the active anti-cytokine immune therapy (ACIT). Surprisingly, clinical studies suggested the interest of this approach during the late 1980's, even before the advent of anti-cytokine passive immunotherapy. In this review, we first explain the involvement of several cytokines in many common diseases involving cytokine overproduction, and identify key targets for anti-cytokine treatments. We then present an update on current advances in preclinical and clinical development of passive anti-cytokine therapeutic approaches. We further discuss progresses in the promising field of active anti-cytokine immunotherapy. Cytokine receptors biologics and small molecules developed using structure/function information, which also constitute important options for treating the cytokine-mediated diseases, are not discussed in this review.

• Monocyte/macrophage trafficking in acquired immunodeficiency syndrome encephalitis: lessons from human and nonhuman primate studies.

  Authors: Tracy Fischer-Smith, Christie Bell, Sidney Croul, Mark Lewis, Jay Rappaport

  Journal of neurovirology. 09/2008; 14(4):318-26.

  Here the authors discuss evidence in human and animal models supporting two opposing views regarding the pathogenesis of human immunodeficiency virus (HIV) in the central nervous system (CNS): (1)Here the authors discuss evidence in human and animal models supporting two opposing views regarding the pathogenesis of human immunodeficiency virus (HIV) in the central nervous system (CNS): (1) HIV infection in the CNS is a compartmentalized infection, with the virus-infected macrophages entering the CNS early, infecting resident microglia and astrocytes, and achieving a state of latency with evolution toward a fulminant CNS infection late in the course of disease; or alternatively, (2) events in the periphery lead to altered monocyte/macrophage (MPhi) homeostasis, with increased CNS invasion of infected and/or uninfected MPhis. Here the authors have reevaluated evidence presented in the favor of the latter model, with a discussion of phenotypic characteristics distinguishing normal resident microglia with those accumulating in HIV encephalitis (HIVE). CD163 is normally expressed by perivascular MPhi s but not resident microglia in normal CNS of humans and rhesus macaques. In agreement with other studies, the authors demonstrate expression of CD163 by brain MPhi s in HIVE and simian immunodeficiency virus encephalitis (SIVE). CNS tissues from HIV-sero positive individuals with HIVE or HIV-associated progressive multifocal leukoencephalopathy (PML) were also examined. In HIVE, the authors further demonstrate colocalization of CD163 and CD16 (Fcgamma III recptor) gene expression, the latter marker associated with HIV infection of monocyte in vivo and permissivity of infection. Indeed, CD163(+) MPhis and microglia are often productively infected in HIVE CNS. In SIV infected rhesus macaques, CD163(+) cells accumulate perivascularly, within nodular lesions and the parenchyma in animals with encephalitis. Likewise, parenchymal microglia and perivascular MPhi s are CD163(+) in HIVE. In contrast to HIVE, CD163(+)perivascular and parenchymal MPhi s in HIV-associated PML were only associated with areas of demyelinating lesions. Interestingly, SIV-infected rhesus macaques whose viral burden was predominantly at 1 x 10(6) copies/ml or greater developed encephalitis. To further investigate the relationship between CD163(+)/CD16(+) MPhis/microglia in the CNS and altered homeostasis in the periphery, the authors performed flow-cytometric analyses of peripheral blood mononuclear cells (PBMCs) from SIV-infected rhesus macaques. The results demonstrate an increase in the percent frequency of CD163(+)/CD16(+) monocytes in animals with detectable virus that correlated significantly with increased viral burden and CD4(+) T-cell decline. These results suggest the importance of this monocyte subset in HIV/SIV CNS disease, and also in the immune pathogenesis of lentiviral infection. The authors further discuss the potential role of CD163(+)/CD16(+) monocyte/MPhi subset expansion, altered myeloid homeostasis, and potential consequences for immune polarization and suppression. The results and discussion here suggest new avenues for the development of acquired immunodeficiency syndrome (AIDS) therapeutics and vaccine design.

• Puralpha as a cellular co-factor of Rev/RRE-mediated expression of HIV-1 intron-containing mRNA.

  Authors: Rafal Kaminski, Nune Darbinian, Bassel E Sawaya, Dorota Slonina, Shohreh Amini, Edward M Johnson, Jay Rappaport, Kamel Khalili, Armine Darbinyan

  Journal of cellular biochemistry. 04/2008; 103(4):1231-45.

  To ensure successful replication, HIV-1 has developed a Rev-mediated RNA transport system that promotes the export of unspliced genomic RNA from nuclei to cytoplasm. This process requires the RevTo ensure successful replication, HIV-1 has developed a Rev-mediated RNA transport system that promotes the export of unspliced genomic RNA from nuclei to cytoplasm. This process requires the Rev responsive element (RRE) that is positioned in the viral transcript encoding Env protein, as well as in unspliced and singly spliced viral transcripts. We identified Puralpha, a single-stranded nucleic acid binding protein as a cellular partner for Rev that augments the appearance of unspliced viral RNAs in the cytoplasm. A decrease in the level of Puralpha expression by siRNA diminishes the level of Rev-dependent expression of viral RNA. Through its nucleic acid binding domain, Puralpha exhibits the ability to interact with the multimerization and RBD domains of Rev. Similar to Rev, Puralpha associates with RRE and in the presence of Rev forms a complex with slower electrophoretic mobility than those from Rev:RRE and Puralpha:RRE. The interaction of Puralpha with RRE occurs in the cytoplasm where enhanced association of Rev with RRE is observed. Our data indicate that the partnership of Puralpha with Rev is beneficial for Rev-mediated expression of the HIV-1 genome.

• Regulation of complement component C3 in astrocytes by IL-1beta and morphine.

  Authors: Jeffrey Maranto, Jay Rappaport, Prasun K Datta

  Journal of neuroimmune pharmacology : the official journal of the Society on NeuroImmune Pharmacology. 04/2008; 3(1):43-51.

  Substances of abuse, such as opiates, and astroglial-derived proinflammatory cytokines, such as interleukin (IL)-1beta, likely contribute to the neuroinflammatory and neurodegenerative processesSubstances of abuse, such as opiates, and astroglial-derived proinflammatory cytokines, such as interleukin (IL)-1beta, likely contribute to the neuroinflammatory and neurodegenerative processes observed in NeuroAIDS in injection drug users. Furthermore, uncontrolled synthesis and activation of complement component C3 in the brain can also lead to inflammation and neurodegeneration. We hypothesized that morphine may alter regulation of the C3 gene by IL-1beta in astrocytes. Our studies demonstrate that IL-1beta induces C3 promoter activity in a CAAT/enhancer-binding protein (C/EBP)-dependent manner. Inhibition of IL-1beta mediated C3 promoter activation by the dominant negative mutant of p38-alpha mitogen-activated protein kinase suggests that IL-1beta induces C3 expression through the activation of C/EBP. Morphine (0.01 microM) in combination with IL-1beta further induced C3 promoter activity. Similarly, the C/EBP-beta isoform liver activating protein and C/EBP-delta-induced C3 promoter activity were upregulated by morphine and IL-1beta. Taken together, this study illustrates that morphine modulates IL-1beta-mediated C3 expression in astrocytic cells.

• CD163/CD16 coexpression by circulating monocytes/macrophages in HIV: potential biomarkers for HIV infection and AIDS progression.

  Authors: Tracy Fischer-Smith, Ellen M Tedaldi, Jay Rappaport

  AIDS research and human retroviruses. 04/2008; 24(3):417-21.

  Monocytes and macrophages play a prominent role in the establishment of HIV-1 infection, virus dissemination, and development of viral reservoirs. Like T cells, macrophages display immuneMonocytes and macrophages play a prominent role in the establishment of HIV-1 infection, virus dissemination, and development of viral reservoirs. Like T cells, macrophages display immune polarization that can promote or impair adaptive immunity. We hypothesize that dysregulation of monocyte/macrophage activation and differentiation may promote immune dysfunction and contribute to AIDS pathogenesis. Using flow cytometry, we analyzed the frequency of monocyte subsets in human immunodeficiency virus type 1 (HIV-1) infection relative to seronegative controls, focusing on the CD163(+)/CD16(+) monocyte as a likely precursor of the "alternatively activated" macrophage. Individuals with detectable HIV-1 infection showed an increase in the frequency of CD163(+)/CD16(+) monocytes (CD14(+)) when compared to seronegative or HIV-1-infected persons with undetectable viral loads. A positive correlation between increased CD163(+)/CD16(+) monocyte frequency and viral load was revealed that was not seen between viral load and the number of CD4(+) T cells or frequency of CD16(+) monocytes (without CD163 subtyping). We also found a strong inverse correlations between CD16(+) monocytes (r = -0.71, r(2) = 0.5041, p = 0.0097) or CD163(+)/CD16(+) monocytes (r = -0.86, r(2) = 0.7396, p = 0.0003) and number of CD4(+) T cells below 450 cells/microl. An inverse relationship between CD163(+)/CD16(+) and CD163(+)/CD16() monocytes suggests the expanded CD163(+)/CD16(+) population is derived exclusively from within the "alternatively activated" (MPhi-2) subset. These data suggest a potential role for CD163(+)/CD16(+) monocytes in virus production and disease progression. CD163(+)/CD16(+) monocytes may be a useful biomarker for HIV-1 infection and AIDS progression and a possible target for therapeutic intervention.

• Early establishment and antigen dependence of simian immunodeficiency virus-specific CD8+ T-cell defects.

  Authors: Yvonne M Mueller, Constantinos Petrovas, Duc H Do, Susan R Altork, Tracy Fischer-Smith, Jay Rappaport, John D Altman, Mark G Lewis, Peter D Katsikis

  Journal of virology. 11/2007; 81(20):10861-8.

  Differentiation and survival defects of human immunodeficiency virus (HIV)-specific CD8(+) T cells may contribute to the failure of HIV-specific CD8(+) T cells to control HIV replication. It is notDifferentiation and survival defects of human immunodeficiency virus (HIV)-specific CD8(+) T cells may contribute to the failure of HIV-specific CD8(+) T cells to control HIV replication. It is not known, however, whether simian immunodeficiency virus (SIV)-infected rhesus macaques show comparable defects in these virus-specific CD8(+) T cells or when such defects are established during infection. Peripheral blood cells from acutely and chronically infected rhesus macaques were stained ex vivo for memory subpopulations and examined by in vitro assays for apoptosis sensitivity. We show here that SIV-specific CD8(+) T cells from chronically SIV infected rhesus macaques show defects comparable to those observed in HIV infection, namely, a skewed CD45RA(-) CD62L(-) effector memory phenotype, reduced Bcl-2 levels, and increased levels of spontaneous and CD95-induced apoptosis of SIV-specific CD8(+) T cells. Longitudinal studies showed that the survival defects and phenotype are established early in the first few weeks of SIV infection. Most importantly, they appear to be antigen driven, since most probably the loss of epitope recognition due to viral escape results in the reversal of the phenotype and reduced apoptosis sensitivity, something we observed also for animals treated with antiretroviral therapy. These findings further support the use of SIV-infected rhesus macaques to investigate the phenotypic changes and apoptotic defects of HIV-specific CD8(+) T cells and indicate that such defects of HIV-specific CD8(+) T cells are the result of chronic antigen stimulation.

• Evidence for the involvement of Puralpha in response to DNA replication stress.

  Authors: Huichen Wang, Meijuan Wang, Krzysztof Reiss, Nune Darbinian-Sarkissian, Edward M Johnson, George Iliakis, Shohreh Amini, Kamel Khalili, Jay Rappaport

  Cancer biology & therapy. 05/2007; 6(4):596-602.

  Puralpha is a sequence-specific nucleic acid binding protein that is involved in multiple cellular functions including regulation of transcription, initiation of DNA replication, cell cyclePuralpha is a sequence-specific nucleic acid binding protein that is involved in multiple cellular functions including regulation of transcription, initiation of DNA replication, cell cycle progression, and neuronal cell differentiation. Its potential role in DNA repair has not been explored. We have now analyzed the role of Puralpha in the cellular response to replication-associated DNA repair of double-strand breaks (DSBs) using Puralpha knockout mouse embryo fibroblasts (MEFs). We found that Puralpha negative cells are hypersensitive to the DNA replication inhibitor, hydroxyurea (HU), and that HU induces excessive DSBs, which delayed the resumption of cell cycle progression after HU treatment. Reintroduction of Pura into Pura null cells reduced the accumulation of DSBs and enhanced DNA end joining. These results suggest a role for Puralpha as a caretaker protein that is involved in the repair of DSBs induced by stalled replication forks.

• Cross-interaction between JC virus agnoprotein and human immunodeficiency virus type 1 (HIV-1) Tat modulates transcription of the HIV-1 long terminal repeat in glial cells.

  Authors: Dorota Kaniowska, Rafal Kaminski, Shohreh Amini, Sujatha Radhakrishnan, Jay Rappaport, Edward Johnson, Kamel Khalili, Luis Del Valle, Armine Darbinyan

  Journal of virology. 10/2006; 80(18):9288-99.

  The human polyomavirus JC virus (JCV) is the causative agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML), which is commonly seen in AIDS patients. TheThe human polyomavirus JC virus (JCV) is the causative agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML), which is commonly seen in AIDS patients. The bicistronic viral RNA, which is transcribed at the late phase of infection, is responsible for expressing the viral capsid proteins and a small regulatory protein, agnoprotein. Immunohistochemical analysis of brain tissue from subjects with AIDS/PML revealed colocalization of the human immunodeficiency virus type 1 (HIV-1) transactivator, Tat, and JCV agnoprotein in nucleus and cytoplasm of "bizarre" astrocytes. In accord with this observation, we detected the copresence of agnoprotein and Tat in human astrocytes upon infection with JCV and HIV-1 or in astrocytic cells expressing these proteins after transfection. Interestingly, results from infection of human astrocytes with HIV-1 and JCV showed a decrease in the level of HIV-1 replication in cells that are coinfected with JCV. Conversely, a slight increase in the level of JCV replication was observed in the presence of HIV-1. The copresence of JCV and HIV-1 in astrocytes prompted us to investigate the possible cross-interaction of agnoprotein with Tat and its impact on HIV-1 gene transcription. Our results demonstrate that agnoprotein through its N-terminal domain associates with Tat and the interaction causes the suppression of Tat-mediated enhancement of HIV-1 promoter activity in these cells. Results from RNA and protein binding assays showed that agnoprotein can inhibit the association of Tat with its target RNA sequence, TAR, and with cyclin T1. Furthermore, agnoprotein is able to interfere with cross-interaction of Tat with the p65 subunit of NF-kappaB and Sp1, whose functions are critical for Tat activation of the long terminal repeat. These observations unravel a new pathway for the molecular interaction of these two viruses in biologically relevant cells in the brains of AIDS/PML patients.

• Dysregulation of NGF-signaling and Egr-1 expression by Tat in neuronal cell culture.

  Authors: Nune Darbinian-Sarkissian, Marta Czernik, Francesca Peruzzi, Jennifer Gordon, Jay Rappaport, Krzysztof Reiss, Kamel Khalili, Shohreh Amini

  Journal of cellular physiology. 10/2006; 208(3):506-15.

  Examination of signal transduction pathways that modulate neuronal cell differentiation and protection against apoptosis has revealed a central role for the MAPK/Erk cascade. The activation ofExamination of signal transduction pathways that modulate neuronal cell differentiation and protection against apoptosis has revealed a central role for the MAPK/Erk cascade. The activation of MAPK/Erk through the TrkA NGF signaling pathway is critical for growth and survival of neuronal cells. Here, we investigate the impact of HIV-1 Tat on the NGF-signaling pathway in SK-N-MC neuroblastoma cells. Expression of Tat decreased cell growth and induced apoptosis. Our results revealed dysregulation of various steps involved in the NGF pathway including suppression of MAPK, and inhibition of the promoter activity of Egr-1, a key pleiotropic mediator of the expression of genes involved in cell growth upon expression of Tat in SK-N-MC cells. Similarly, exposure of SK-N-MC to conditioned media derived from cells expressing Tat decreased phosphorylation of MAPK and reduced the level of Egr-1 protein expression in SK-N-MC cells. Furthermore, MAPK was able to phosphorylate Puralpha, a cellular protein that plays an important role in neuronal cell function and differentiation, and this was inhibited by Tat. The ability of Puralpha to interact with a GA/GC-rich sequence positioned upstream from the transcription start site of the Egr-1 promoter provided a rationale to examine Egr-1 expression. Expression of Tat decreased NGF-induced Egr-1 levels in SK-N-MC cells and reduced binding of Puralpha to the Egr-1 promoter. All of these observations support a model where the interplay between Tat and Puralpha dysregulates the NGF pathway including the MAPK/Erk network, resulting in reduced expression and activity of Egr-1 in neuronal cells.

• Macrophage colony-stimulating factor in the pathogenesis of HIV infection: potential target for therapeutic intervention.

  Authors: Valerie Haine, Tracy Fischer-Smith, Jay Rappaport

  Journal of neuroimmune pharmacology : the official journal of the Society on NeuroImmune Pharmacology. 04/2006; 1(1):32-40.

  Macrophage colony stimulating factor (M-CSF) appears to play a major role in promoting and maintaining reservoirs of human immunodeficiency virus type 1 (HIV-1) in infected individuals. HIV-1Macrophage colony stimulating factor (M-CSF) appears to play a major role in promoting and maintaining reservoirs of human immunodeficiency virus type 1 (HIV-1) in infected individuals. HIV-1 infection induces production of M-CSF by macrophages, which in turn promotes further infection of macrophages via increases in CD4 and CCR5 receptors, as well as increases in virus gene expression. M-CSF promotes the ontogeny and survival of macrophages, contributing to both the number and longevity of these infected cells. M-CSF dysregulation promotes the differentiation of monocytes toward macrophages and osteoclasts and at the same time may inhibit differentiation toward dendritic cells, resulting in immune impairment. The potential role of M-CSF in HIV-associated end organ diseases including HIV-associated dementia, HIV-associated nephropathy, and osteoporosis is discussed. This review emphasizes the need for developing M-CSF antagonists for treatment of HIV-1-infected patients.

• Evolving paradigms in the pathogenesis of HIV-1-associated dementia.

  Authors: Tracy Fischer-Smith, Jay Rappaport

  Expert reviews in molecular medicine. 01/2006; 7(27):1-26.

  HIV-1-associated dementia (HIV-D) remains a significant consequence of HIV-1 infection and AIDS. Since the clinical introduction of highly active antiretroviral therapy (HAART), the incidence ofHIV-1-associated dementia (HIV-D) remains a significant consequence of HIV-1 infection and AIDS. Since the clinical introduction of highly active antiretroviral therapy (HAART), the incidence of HIV-D has decreased, yet the prevalence has increased as patients are living longer under treatment. Additionally, a less severe form of HIV-D, minor cognitive motor disorder, has become an increasing issue. Two different models have been proposed for virus entry in the central nervous system (CNS) in HIV-D. In the 'Trojan horse' model, the virus enters the CNS early carried by macrophages and infects resident glia; later in the course of infection, virus replication is activated and additional monocyte/macrophages are recruited into the CNS via cytokine/chemokine networks and endothelial-cell-leukocyte interactions at the blood-brain barrier. In the 'late invasion' model, an inherently invasive activated monocyte subset is expanded from bone marrow as a result of immune dysregulation in the periphery in the setting of AIDS. In this review we discuss these two separate, although not mutually exclusive, means for virus entry and persistence in the CNS. Additionally, we explore mechanisms for neuronal injury and apoptosis, including the role of virus, viral and host proteins, oxidative stress and products of infected or uninfected activated microglia and astrocytes. Potential therapeutic strategies are also briefly discussed.

• Cross talk between growth factors and viral and cellular factors alters neuronal signaling pathways: implication for HIV-associated dementia.

  Authors: Francesca Peruzzi, Valeria Bergonzini, Susanna Aprea, Krzysztof Reiss, Bassel E Sawaya, Jay Rappaport, Shohreh Amini, Kamel Khalili

  Brain research. Brain research reviews. 01/2006; 50(1):114-25.

  HIV-associated dementia (HAD) is a serious neurological disorder affecting about 7% of people with AIDS. In the brain, HIV-1 infects a restricted number of cell types, being primarily present inHIV-associated dementia (HAD) is a serious neurological disorder affecting about 7% of people with AIDS. In the brain, HIV-1 infects a restricted number of cell types, being primarily present in macrophages and microglial cells, less abundant in astrocytes, and rarely seen in oligodendrocytes and neurons. Lack of a productive HIV-1 infection of neuronal cells suggests the presence of an indirect pathway by which the virus may determine the brain pathology and neuronal dysfunction seen in AIDS patients. Among the participants in this event, viral proteins including gp120 and Tat, along with host factors including cytokines, chemokines, and several signaling pathways have received considerable attention. In this article, we discuss the most recent concepts pertaining to the mechanisms of HIV-1-induced neuronal dysfunction by highlighting the interplay between signal transduction pathways activated by viral and host factors and their consequences in neuronal cell function.

• Genomic approach of AIDS pathogenesis: exhaustive genotyping of the TNFR1 gene in a French AIDS cohort.

  Authors: Gora Diop, Jean-Louis Spadoni, Hervé Do, Thomas Hirtzig, Cédric Coulonges, Taoufik Labib, Wolfgang Issing, Jay Rappaport, Amu Therwath, Mark Lathrop, Fumihiko Matsuda, Jean-François Zagury

  Biomedicine & pharmacotherapy = Biomédecine & pharmacothérapie. 10/2005; 59(8):474-80.

  Large-scale genomic studies in cohorts have been made possible for the last few years thanks to the progress of molecular biology and bioinformatics. This systematic approach allows a betterLarge-scale genomic studies in cohorts have been made possible for the last few years thanks to the progress of molecular biology and bioinformatics. This systematic approach allows a better understanding of the molecular mechanisms of disease development and as a consequence can contribute to the rational design of new diagnostic and therapeutic tools. We present here the exhaustive genotyping of a candidate gene, tumor necrosis factor receptor 1 (TNFR1), in the genetic of resistance to immunodeficiency virus (GRIV) AIDS cohort. This gene was chosen because it is likely to be involved in the apoptosis pathways of CD4+ and CD8+ T-cells during human immunodeficiency virus 1 (HIV-1) infection. Seven frequent polymorphisms were characterized in 319 HIV-1 seropositive patients from the GRIV cohort with extreme disease progression phenotypes, slow progression or rapid progression, and in 427 healthy controls. The TNFR1 gene locus does not appear to be part of any haploblock and contains only a small haploblock of two successive SNPs. One promoter SNP (TNFR1_17444594, position -581) and one intronic SNP (TNFR1_27223241, position +11511) gave weak positive signals of association (resp. P=0.03 and P=0.04) as well as two haplotypes. To our knowledge, this is the first genetic association study dealing with the TNFR1 gene in AIDS and the putative associations identified will need to be validated through other AIDS cohort analyses or by further biological experimentation.