Temporal and subunit-specific modulations of the Rel/NF-kappaB transcription factors through CD28 costimulation.
Stimulation of highly purified primary T lymphocytes through CD2 and CD28 adhesion molecules induces a long-term proliferation, dependent on persistent autocrine secretion of interleukin 2 (IL-2), high and prolonged expression of inducible CD25/IL-2 receptor alpha chain (IL-2Ralpha), and secretion of growth factors such as the granulocyte-macrophage colony-stimulating factor (GM-CSF). CD28 costimulation appears to activate cytokine gene expression through conserved kappaB-related CD28 response (CD28RE) or cytokine 1 (CK-1) elements in addition to canonical NF-kappaB-binding sites. In this report, we assess: 1) the evolution of the expression, over an 8-day time period, of the Rel/NF-kappaB family of proteins in costimulated versus TcR/CD3-stimulated primary T cells; 2) the impact of changes on the in vitro occupancy of GM-CSF kappaB and CK-1, as well as IL-2Ralpha kappaB sites; and 3) the differential regulation of newly synthesized p65 and c-Rel by IkappaB proteins. We show that CD2+CD28 stimulation specifically induces, at maximal T cell proliferation phase, sustained nuclear overexpression of NFKB2 p52 and c-Rel subunits which might rely on long-lasting processing of p100 precursor for p52 and increased neosynthesis of c-Rel. This up-regulation correlates with sustained occupancy of GM-CSF kappaB and CK-1 elements by both proteins. Conversely, these subunits do not appear to bind to the IL-2Ralpha kappaB site. Costimulation, but not TcR/CD3 stimulation, appears supported by sustained down-regulation of both IkappaBalpha and -beta regulators. Furthermore, contrary to p65, c-Rel appears to display little affinity for p105, p100 and IkappaBalpha regulators.
Kahn-Perlès
B
B
Unité de Cancérologie Expérimentale, U119 INSERM, 27 boulevard Leï Roure, 13009 Marseille, France.
Lipcey
C
C
Lécine
P
P
Olive
D
D
Imbert
J
J
D018106:CD28 Antigens / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit; D052003:NF-kappa B p52 Subunit; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013997:Time Factors; D051996:Transcription Factor RelA; D051841:Transcription Factor RelB; D014157:Transcription Factors
D018106:CD28 Antigens; D016207:Cytokines; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D052003:NF-kappa B p52 Subunit; D011518:Proto-Oncogene Proteins; C497593:RELB protein, human; D015375:Receptors, Interleukin-2; D051996:Transcription Factor RelA; D014157:Transcription Factors; D051841:Transcription Factor RelB; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004247:DNA