title: 15-Deoxy-Delta12,14-prostaglandin J2 inhibits HIV-1 transactivating protein, Tat, through covalent modification.
abstract: Controlling the HIV/AIDS epidemic remains a major challenge, with approximately 5 million new HIV infections annually. Cyclopentenone prostaglandins (CyPG), such as 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)), are arachidonic acid-derived endogenous electrophiles that possess anti-HIV activity by an unknown mechanism. Given that the reactive alpha,beta-unsaturated ketone in the cyclopentenone ring of 15d-PGJ(2) covalently modifies key Cys thiols in select proteins, we hypothesized that 15d-PGJ(2) inhibits HIV transcription and replication by targeting Cys thiols in HIV-1 Tat. Tat is a potent transactivator of viral gene expression required for HIV transcriptional elongation and replication. Our studies indicate that 15d-PGJ(2) treatment of cells inhibits Tat-dependent transcription and replication of HIV-1, while 9,10-dihydro-15d-PGJ(2), PGE(2), PGF(2alpha), or PGD(2) that lack the reactive alpha,beta-unsaturated ketone were ineffective. The inhibition of Tat activity by 15d-PGJ(2) was dose-dependent, with an IC(50) of 1.2 microM and independent of NF-kappaB pathway. Furthermore, using a biotinylated derivative of 15d-PGJ(2), we demonstrate that 15d-PGJ(2) modifies free Cys-thiols in Tat to form covalent Michael adducts and that the interaction was further increased on reduction of Tat. 15d-PGJ(2)-modified Tat was unable to transactivate the HIV long terminal repeat in U937 human macrophages. These data demonstrate that Tat acts as a molecular target of CyPG leading to the inhibition of transcription and also suggest a novel therapeutic approach to complement current antiretroviral strategies for HIV/AIDS.
authors.affiliation: Center for Molecular Immunology and Infectious Disease, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Parisa
authors.initials: P
authors.lastname: Kalantari
authors.forename: Vivek
authors.initials: V
authors.lastname: Narayan
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Henderson
authors.forename: K Sandeep
authors.initials: KS
authors.lastname: Prabhu
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D003545:Cysteine / Q000737:chemistry; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000494:pharmacology; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D020298:U937 Cells; D014779:Virus Replication / Q000187:drug effects; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics
chemical_list: C534416:15-deoxy-9,10-dihydro-delta(12,14)-prostaglandin J2; C477819:15-deoxyprostaglandin J2; D019380:Anti-HIV Agents; D016328:NF-kappa B; D011994:Recombinant Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus; D003545:Cysteine; D015230:Prostaglandin D2