Aging, immunosenescence and membrane rafts: the lipid connection.
The decreased efficiency of immune responses in older people is partly a consequence of alterations in T lymphocyte functions caused by modifications in the early events of signal transduction. Several alterations in the signaling pathways of T lymphocytes have been described in older humans and animals. A unifying cause could be modifications in the physicochemical properties of the plasma membrane resulting from changes in its lipid composition and the distribution and function of lipid rafts (LR). The latter serve to assemble the initial components of the signaling cascade. Accumulating data suggest that the function of plasma membrane LR is altered with aging; we hypothesize that this would significantly contribute to immune dysregulation. The role of aging and cholesterol in LR functions in T lymphocytes is reviewed and discussed here.
Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada ; Research Center on Aging, University of Sherbrooke, 1036, rue Belvedere Sud, Sherbrooke, Qc, J1H 4C4, Canada.
Tamas
T
Fulop
Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada.
Aurélie
A
Le Page
Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada.
Hugo
H
Garneau
Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada.
Naheed
N
Azimi
Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada.
Sarra
S
Baehl
Department of Biochemistry, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada.
Gilles
G
Dupuis
Center for Medical Research, Tübingen Aging and Tumor Immunology Group, University of Tübingen, Waldhörnlestrasse 22, Tübingen, D-72072, Germany.
Graham
G
Pawelec
Singapore Immunology Network (SIgN), Immunos Building/Biopolis, Agency for Science Technology and Research (ASTAR), 8A Biomedical Grove, Singapore, 138648, Singapore.
Anis
A
Larbi
Cholesterol; Immune synapse; Immunosenescence; Lipid rafts; Signal transduction; T cells