1. Palbociclib, a selective inhibitor of cyclin-dependent kinase4/6, blocks HIV-1 reverse transcription through the control of sterile α motif and HD domain-containing protein-1 (SAMHD1) activity
- Author
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Roger Badia, Alba Ruiz, José A. Esté, Marc Permanyer, Javier Torres-Torronteras, Eduardo Pauls, Bonaventura Clotet, Ester Ballana, Eva Riveira-Muñoz, and Ramon Martí
- Subjects
Anti-HIV Agents ,Pyridines ,Immunology ,Palbociclib ,Real-Time Polymerase Chain Reaction ,Piperazines ,SAM Domain and HD Domain-Containing Protein 1 ,Cyclin-dependent kinase ,Immunology and Allergy ,Humans ,Protein Kinase Inhibitors ,Cells, Cultured ,Monomeric GTP-Binding Proteins ,biology ,Kinase ,Cyclin-dependent kinase 2 ,Cyclin-Dependent Kinase 2 ,Cyclin-Dependent Kinase 6 ,Reverse Transcription ,Molecular biology ,Reverse transcriptase ,Infectious Diseases ,DNA, Viral ,biology.protein ,HIV-1 ,Leukocytes, Mononuclear ,Phosphorylation ,Cyclin-dependent kinase 6 ,SAMHD1 - Abstract
Background: Sterile α motif and HD domain-containing protein-1 (SAMHD1) inhibits HIV-1 reverse transcription by decreasing the pool of intracellular deoxynucleotides. SAMHD1 is controlled by cyclin-dependent kinase (CDK)-mediated phosphorylation. However, the exact mechanism of SAMHD1 regulation in primary cells is unclear. We explore the effect of palbociclib, a CDK6 inhibitor, in HIV-1 replication. Methods: Human primary monocytes were differentiated into macrophages with monocyte-colony stimulating factor and CD4+ T lymphocytes stimulated with phytohaemagglutinin (PHA)/interleukin-2. Cells were treated with palbociclib and then infected with a Green fluorescent protein-expressing HIV-1 or R5 HIV-1 BaL. Viral DNA was measured by quantitative PCR and infection assessed by flow cytometry. Deoxynucleotide triphosphate (dNTP) content was determined using a polymerase-based method. Results: Pan-CDK inhibitors AT7519, roscovitine and purvalanol A reduced SAMHD1 phosphorylation. HIV-1 replication was blocked by AT7519 (66.4 ± 3.8%; n = 4), roscovitine (47.3 ± 3.9%; n = 4) and purvalanol A (55.7 ± 15.7%; n = 4) at subtoxic concentrations. Palbociclib, a potent and selective CDK6 inhibitor, blocked SAMHD1 phosphorylation, intracellular dNTP levels, HIV-1 reverse transcription and HIV-1 replication in primary macrophages and CD4+ T lymphocytes. Notably, treatment of macrophages with palbociclib led to reduced CDK2 activation, measured as the phosphorylation of the T-loop at the Thr160. The antiviral effect was lost when SAMHD1 was degraded by Vpx, providing further evidence for a role of SAMHD1 in mediating the antiretroviral effect. Conclusions: Our results indicate that SAMHD1-mediated HIV-1 restriction is controlled by CDK as previously suggested but point to a preferential role for CDK2 and CDK6 as mediators of SAMHD1 activation. Our study provides a new signaling pathway susceptible for the development of new therapeutic approaches against HIV-1 infection.
- Published
- 2014