Three-dimensional microscopy characterization of death receptor 5 expression by over-activated human primary CD4+ T cells and apoptosis

• Published in: PloS one Vol. 7; no. 3; p. e32874
• Main Authors: Barblu, Lucie, Herbeuval, Jean-Philippe
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 06-03-2012; Public Library of Science (PLoS)
• Subjects: Acquired immune deficiency syndrome; AIDS; Apoptosis; Apoptosis - genetics; Apoptosis - immunology; Biology; Blocking antibodies; CD4 antigen; CD4-Positive T-Lymphocytes - immunology; CD4-Positive T-Lymphocytes - metabolism; Cell activation; Cell death; Cells, Cultured; Cytoplasm; Damage prevention; Death receptors; Engineering Sciences; Gene Expression; Gene Silencing; Humans; Immune response; Immune system; Lymphocyte Activation - immunology; Lymphocytes; Lymphocytes T; Microscopy; Microscopy, Fluorescence; Mortality; mRNA; Other; phytohemagglutinins; Phytohemagglutinins - immunology; Plasma membranes; Receptors; Receptors, TNF-Related Apoptosis-Inducing Ligand - genetics; Receptors, TNF-Related Apoptosis-Inducing Ligand - metabolism; Ribonucleic acid; RNA; RNA Interference; RNA-mediated interference; siRNA; T cell receptors; TRAIL protein; Tumor cells; Tumor necrosis factor; Tumor necrosis factor-TNF
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0032874

Activation-induced cell death is a natural process that prevents tissue damages from over-activated immune cells. TNF-Related apoptosis ligand (TRAIL), a TNF family member, induces apoptosis of infected and tumor cells by binding to one of its two death receptors, DR4 or DR5. TRAIL was reported to be secreted by phytohemagglutinin (PHA)-stimulated CD4(+) T cells in microvesicles.We investigate here TRAIL and DR5 regulation by activated primary CD4(+) T cells and its consequence on cell death. We observed that PHA induced CD4(+) T cell apoptosis in a dose-dependent manner. Thus, we investigated molecules involved in PHA-mediated cell death and demonstrated that TRAIL and DR5 were over-expressed on the plasma membrane of PHA-stimulated CD4(+) T cells. Surprisingly, DR5 was constitutively expressed in naive CD4(+) T cells at messenger RNA (mRNA) and protein levels. Thus, using 3 dimensional microscopy and intracellular staining assays, we show that DR5 is constitutively expressed in CD4(+) T cells and is pre-stocked in the cytoplasm. When cells are stimulated by PHA, DR5 is relocalized from cytoplasm to plasma membrane. Small interference RNA (siRNA) and blocking antibody assays demonstrate that TRAIL/DR5 interaction is mainly responsible for PHA-mediated CD4(+) T cell apoptosis. Thus, membrane DR5 expression leading to TRAIL-mediated apoptosis may represent one of the pathways responsible for eradication of over-activated CD4(+) T cells during immune responses.