HIV-1 gp120 induces type-1 programmed cell death through ER stress employing IRE1α, JNK and AP-1 pathway

Sci Rep. 2016 Jan 7:6:18929. doi: 10.1038/srep18929.

Abstract

The ER stress-mediated apoptosis has been implicated in several neurodegenerative diseases; however, its role in HIV/neuroAIDS remains largely unexplored. The present study was undertaken to assess the involvement and detailed mechanism of IRE1α pathway in HIV-1 gp120-mediated ER stress and its possible involvement in cell death. Various signaling molecules for IRE1α pathway were assessed using SVGA cells, primary astrocytes and gp120 transgenic mice, which demonstrated gp120-mediated increase in phosphorylated JNK, XBP-1 and AP-1 leading to upregulation of CHOP. Furthermore, HIV-1 gp120-mediated activation of IRE1α also increased XBP-1 splicing. The functional consequence of gp120-mediated ER stress was determined via assessment of gp120-mediated cell death using PI staining and MTT assay. The gp120-mediated cell death also involved caspase-9/caspase-3-mediated apoptosis. These findings were confirmed with the help of specific siRNA for IRE1α, JNK, AP-1, BiP and CHOP showing significant reduction in gp120-mediated CHOP expression. Additionally, silencing all the intermediates also reduced the gp120-mediated cell death and caspase-9/caspase-3 activation at differential levels. This study provides ER-stress as a novel therapeutic target in the management of gp120-mediated cell death and possibly in the treatment of neuroAIDS.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis*
  • Astrocytes / physiology
  • Base Sequence
  • Endoplasmic Reticulum Stress*
  • Endoribonucleases / metabolism*
  • Gene Knockdown Techniques
  • HIV Envelope Protein gp120 / physiology*
  • Humans
  • MAP Kinase Signaling System
  • Male
  • Mice, 129 Strain
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Protein Serine-Threonine Kinases / metabolism*
  • RNA Splicing
  • RNA, Small Interfering / genetics
  • Transcription Factor AP-1 / metabolism*
  • Transcription Factor CHOP / metabolism
  • X-Box Binding Protein 1

Substances

  • DDIT3 protein, human
  • HIV Envelope Protein gp120
  • RNA, Small Interfering
  • Transcription Factor AP-1
  • X-Box Binding Protein 1
  • XBP1 protein, human
  • gp120 protein, Human immunodeficiency virus 1
  • Transcription Factor CHOP
  • ERN1 protein, human
  • Protein Serine-Threonine Kinases
  • Endoribonucleases