Ryanodine receptor signaling is required for anti-CD3-induced T cell proliferation, interleukin-2 synthesis, and interleukin-2 receptor signaling.
Ryanodine receptors (RyR) are involved in regulating intracellular Ca(++) mobilization in T lymphocytes. However, the importance of RyR signaling during T cell activation has not yet been determined. In this study, we have used the RyR-selective antagonists, ruthenium red and dantrolene, to determine the effect of RyR blockade on T cell receptor-mediated activation events and cytokine-dependent T cell proliferation. Both ruthenium red and dantrolene inhibited DNA synthesis and cell division, as well as the synthesis of interleukin (IL)-2 by T lymphocytes responding to mitogenic anti-CD3 antibody. Blockade of RyR at initiation of culture or as late as 24 h after T cell receptor stimulation inhibited T cell proliferation, suggesting a requirement for sustained RyR signaling during cell cycle progression. Although flow cytometry revealed that RyR blockade had little effect on activation-induced expression of the alpha chain (CD25) of the high affinity IL-2 receptor, the inhibitory effect of RyR antagonists could not be reversed by the addition of exogenous IL-2 at initiation of culture. In addition, both ruthenium red and dantrolene had a strong inhibitory effect on IL-2-dependent proliferation of CTLL-2 T cells. These data indicate that RyR are involved in regulating IL-2 receptor signaling that drives T cell progression through the cell cycle. We conclude that RyR-associated Ca(++) signaling regulates T cell proliferation by promoting both IL-2 synthesis and IL-2-dependent cell cycle progression.
Conrad
David M
DM
Department of Microbiology & Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, B3H 1X5 Canada.
Hanniman
Elyisha A
EA
Watson
Carrie L
CL
Mader
Jamie S
JS
Hoskin
David W
DW
D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000494:pharmacology; D017252:CD3 Complex / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005260:Female; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000276:immunology / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D012430:Ruthenium Red / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*
D000906:Antibodies; D017252:CD3 Complex; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D019837:Ryanodine Receptor Calcium Release Channel; D012430:Ruthenium Red; D004247:DNA; D002118:Calcium