Autophagy is involved in T cell death after binding of HIV-1 envelope proteins to CXCR4

J Clin Invest. 2006 Aug;116(8):2161-72. doi: 10.1172/JCI26185.

Abstract

HIV-1 envelope glycoproteins (Env), expressed at the cell surface, induce apoptosis of uninfected CD4+ T cells, contributing to the development of AIDS. Here we demonstrate that, independently of HIV replication, transfected or HIV-infected cells that express Env induced autophagy and accumulation of Beclin 1 in uninfected CD4+ T lymphocytes via CXCR4. The same phenomena occurred in a T cell line and in transfected HEK.293 cells that expressed both wild-type CXCR4 and a truncated form of CD4 that is unable to bind the lymphocyte-specific protein kinase Lck. Env-mediated autophagy is required to trigger CD4+ T cell apoptosis since blockade of autophagy at different steps, by either drugs (3-methyladenine and bafilomycin A1) or siRNAs specific for Beclin 1/Atg6 and Atg7 genes, totally inhibited the apoptotic process. Furthermore, CD4+ T cells still underwent Env-mediated cell death with autophagic features when apoptosis was inhibited. These results suggest that HIV-infected cells can induce autophagy in bystander CD4+ T lymphocytes through contact of Env with CXCR4, leading to apoptotic cell death, a mechanism most likely contributing to immunodeficiency.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Autophagy / immunology*
  • Binding Sites
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / physiology
  • Cell Death / immunology
  • Cell Line
  • Coculture Techniques
  • Gene Products, env
  • HIV Envelope Protein gp120 / genetics
  • HIV Envelope Protein gp120 / metabolism*
  • HIV-1 / metabolism*
  • Humans
  • Kidney
  • Receptors, CXCR4 / metabolism*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / pathology

Substances

  • Gene Products, env
  • HIV Envelope Protein gp120
  • Receptors, CXCR4