title: Reactivation of latent HIV-1 provirus via targeting protein phosphatase-1.
abstract: BACKGROUND
  HIV-1 escapes antiretroviral drugs by integrating into the host DNA and forming a latent transcriptionally silent HIV-1 provirus. This provirus presents the major hurdle in HIV-1 eradication and cure. Transcriptional activation, which is prerequisite for reactivation and the eradication of latent proviruses, is impaired in latently infected T cells due to the lack of host transcription factors, primarily NF-κB and P-TEFb (CDK9/cyclin T1). We and others previously showed that protein phosphatase-1 (PP1) regulates HIV-1 transcription by modulating CDK9 phosphorylation. Recently we have developed a panel of small molecular compounds targeting a non-catalytic site of PP1.
  
  
  RESULTS
  Here we generated a new class of sulfonamide-containing compounds that activated HIV-1 in acute and latently infected cells. Among the tested molecules, a small molecule activator of PP1 (SMAPP1) induced both HIV-1 replication and reactivation of latent HIV-1 in chronically infected cultured and primary cells. In vitro, SMAPP1 interacted with PP1 and increased PP1 activity toward a recombinant substrate. Treatment with SMAPP1 increased phosphorylation of CDK9's Ser90 and Thr186 residues, but not Ser175. Proteomic analysis showed upregulation of P-TEFb and PP1 related proteins, including PP1 regulatory subunit Sds22 in SMAPP1-treated T cells. Docking analysis identified a PP1 binding site for SMAPP1 located within the C-terminal binding pocket of PP1.
  
  
  CONCLUSIONS
  We identified a novel class of PP1-targeting compounds that reactivate latent HIV-1 provirus by targeting PP1, increasing CDK9 phosphorylation and enhancing HIV transcription. This compound represents a novel candidate for anti-HIV-1 therapeutics aiming at eradication of latent HIV-1 reservoirs.
authors.affiliation: Department of Medicine, The George Washington University, Washington, DC, 2003, USA. tmudit@email.gwu.edu.
authors.forename: Mudit
authors.initials: M
authors.lastname: Tyagi
authors.affiliation: National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, 20110, USA. siordans@gmu.edu.
authors.forename: Sergey
authors.initials: S
authors.lastname: Iordanskiy
authors.affiliation: Center for Sickle Cell Disease, Howard University, 1840 7th Street, N.W. HURB1, Suite 202, Washington, DC, 20059, USA. tatiana.ammosova@howard.edu.|Department of Medicine, Howard University, Washington, DC, 20059, USA. tatiana.ammosova@howard.edu.|Yakut Science Center for Complex Medical Problems, Yakutsk, 677019, Russia. tatiana.ammosova@howard.edu.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Ammosova
authors.affiliation: Center for Sickle Cell Disease, Howard University, 1840 7th Street, N.W. HURB1, Suite 202, Washington, DC, 20059, USA. namita.kumari@howard.edu.
authors.forename: Namita
authors.initials: N
authors.lastname: Kumari
authors.affiliation: Center for Sickle Cell Disease, Howard University, 1840 7th Street, N.W. HURB1, Suite 202, Washington, DC, 20059, USA. KASmith8403@aol.com.
authors.forename: Kahli
authors.initials: K
authors.lastname: Smith
authors.affiliation: Center for Sickle Cell Disease, Howard University, 1840 7th Street, N.W. HURB1, Suite 202, Washington, DC, 20059, USA. denitra.breuer@gmail.com.
authors.forename: Denitra
authors.initials: D
authors.lastname: Breuer
authors.affiliation: Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Gatchina, Russia. andreyi@omrb.pnpi.spb.ru.|Instiute of Nanobiotechnologies, St. Petersburg State Polytechnical University, St. Petersburg, Russia. andreyi@omrb.pnpi.spb.ru.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Ilatovskiy
authors.affiliation: Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, 20057, USA. ys452@georgetown.edu.
authors.forename: Yasemin Saygideğer
authors.initials: YS
authors.lastname: Kont
authors.affiliation: Center for Sickle Cell Disease, Howard University, 1840 7th Street, N.W. HURB1, Suite 202, Washington, DC, 20059, USA. Andrei.ivanov@howard.edu.
authors.forename: Andrey
authors.initials: A
authors.lastname: Ivanov
authors.affiliation: Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, 20057, USA. au26@georgetown.edu.
authors.forename: Aykut
authors.initials: A
authors.lastname: Üren
authors.affiliation: Department of Biochemistry and Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA. d.kovalskyy@gmail.com.
authors.forename: Dmytro
authors.initials: D
authors.lastname: Kovalskyy
authors.affiliation: Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Gatchina, Russia. michael.petukhov@yandex.ru.|Instiute of Nanobiotechnologies, St. Petersburg State Polytechnical University, St. Petersburg, Russia. michael.petukhov@yandex.ru.
authors.forename: Michael
authors.initials: M
authors.lastname: Petukhov
authors.affiliation: National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, 20110, USA. fkashanc@gmu.edu.
authors.forename: Fatah
authors.initials: F
authors.lastname: Kashanchi
authors.affiliation: Center for Sickle Cell Disease, Howard University, 1840 7th Street, N.W. HURB1, Suite 202, Washington, DC, 20059, USA. snekhai@howard.edu.|Department of Medicine, Howard University, Washington, DC, 20059, USA. snekhai@howard.edu.
authors.forename: Sergei
authors.initials: S
authors.lastname: Nekhai
mesh_terms: D000998:Antiviral Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D002478:Cells, Cultured; D042863:Cyclin-Dependent Kinase 9 / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D007546:Isoquinolines / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D008954:Models, Biological; D062105:Molecular Docking Simulation; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D042925:Positive Transcriptional Elongation Factor B / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D054645:Protein Phosphatase 1 / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics; D011533:Proviruses / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D013449:Sulfonamides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D014775:Virus Activation; D017735:Virus Latency
chemical_list: D000998:Antiviral Agents; D007546:Isoquinolines; D016328:NF-kappa B; C000606927:SMAPP1 compound; D013449:Sulfonamides; D042925:Positive Transcriptional Elongation Factor B; C467969:CDK9 protein, human; D042863:Cyclin-Dependent Kinase 9; D054645:Protein Phosphatase 1