Bryostatin activates HIV-1 latent expression in human astrocytes through a PKC and NF-ĸB-dependent mechanism

Sci Rep. 2015 Jul 22:5:12442. doi: 10.1038/srep12442.

Abstract

Multiple studies have shown that HIV-1 patients may develop virus reservoirs that impede eradication; these reservoirs include the central nervous system (CNS). Despite an undetectable viral load in patients treated with potent antiretrovirals, current therapy is unable to purge the virus from these latent reservoirs. To broaden the inhibitory range and effectiveness of current antiretrovirals, the potential of bryostatin was investigated as a latent HIV-1 activator. We used primary astrocytes, NHA cells, and astrocytoma cells U-87. Infected cells with HIV-1(NL4.3) were treated with bryostatin alone or in combination with different inhibitors. HIV-1 production was quantified by using ELISA. Transcriptional activity was measured using luciferase reporter gene assays by using lipofectin. We performed cotransfection experiments of the LTR promoter with the active NF-κB member p65/relA. To confirm the NF-κB role, Western blot and confocal microscopy were performed. Bryostatin reactivates latent viral infection in the NHA and U87 cells via activation of protein kinase C (PKC)-alpha and -delta, because the PKC inhibitors rottlerin and GF109203X abrogated the bryostatin effect. No alteration in cell proliferation was found. Moreover, bryostatin strongly stimulated LTR transcription by activating the transcription factor NF-κB. Bryostatin could be a beneficial adjunct to the treatment of HIV-1 brain infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Astrocytes / metabolism*
  • Astrocytes / virology*
  • Bryostatins / pharmacology*
  • Cell Line, Tumor
  • Gene Expression Regulation, Viral / drug effects
  • Gene Expression Regulation, Viral / genetics
  • HIV Infections / metabolism
  • HIV Infections / virology
  • HIV Long Terminal Repeat / drug effects
  • HIV Long Terminal Repeat / genetics
  • HIV-1 / drug effects*
  • HIV-1 / genetics
  • Humans
  • NF-kappa B / metabolism*
  • Promoter Regions, Genetic / drug effects
  • Promoter Regions, Genetic / genetics
  • Protein Kinase C / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / genetics
  • Transcriptional Activation / drug effects
  • Transcriptional Activation / genetics
  • Virus Latency / drug effects*
  • Virus Latency / genetics

Substances

  • Bryostatins
  • NF-kappa B
  • bryostatin 1
  • Protein Kinase C