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Effects of modulators of cytosolic Ca 2+ on phytohemagglutin‐dependent Ca 2+ response and interleukin‐2 production in Jurkat cells
Author(s) -
Dupuis Gilles,
Aoudjit Fawzi,
Ricard Isabelle,
Payet Marcel D.
Publication year - 1993
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.53.1.66
Subject(s) - jurkat cells , ryanodine receptor , nifedipine , biology , cytosol , dhps , biophysics , microbiology and biotechnology , biochemistry , calcium , t cell , medicine , receptor , immunology , enzyme , immune system , plasmodium falciparum , malaria
We have previously reported the presence, in Jurkat T cells, of outward K + currents and inward currents that have been attributed to Ca 2+ channels. Here, we have studied the effects of dimethyl 1,4‐dihydro‐ 2,6‐dimethyl‐4‐(2‐nitrophenyl)‐3,5‐pyridine‐dicarboxylate (nifedipine) and 4‐(2,l,3‐benzoxadiazol‐4‐yl)‐l,4‐dihydro‐ 2,6‐dimethyl‐5‐methoxy‐carbonylpyridine‐3‐carboxylate (PN200‐110), two dihydropyridines (DHPs) known to inhibit voltage‐dependent Ca 2+ channel activity in different types of cells, and two inhibitors of internal Ca 2+ release (muscle cells), ryanodine and 3,4,5‐trimethoxybenzoic acid 8‐(diethylamino)octyl ester (TMB‐8), on the Phaseo‐ lus vulgaris phytohemagglutinin (PHA)‐dependent responses in Jurkat T lymphocytes. Our results show that nifedipine and PN200‐110 inhibit the PHA‐dependent production of interleukin‐2 except when 12‐0‐ tetradecanoyl‐13‐O‐acetyl phorbol is added to the cultures. Ryanodine and TMB‐8 are not inhibitors. The PHA‐dependent Ca 2+ response is significantly reduced when the cells are preincubated in the presence of the DHPs. Under these conditions, ryanodine has only a small inhibitory effect and TMB‐8 has no effect. In contrast, only ryanodine (50 μ M) decreases the PHA‐ dependent cytosolic release of Ca 2+ when the cells are bathed in a medium containing a low concentration of Ca 2+ (60 nM). The inhibitory effects of nifedipine and PN200‐110 may result from the binding of these DHPs to specific receptor sites as revealed by studies using [ 3 H]PN200‐110 ( K D ‐ 8.5 ± 3.1 nM; 2300 ± 500 apparent binding sites/cell). Photoaffinity labeling studies using [ 3 H]azidopine as a probe showed specific incorporation of label into three glycoproteins of molecular mass (± SD) 170 ± 13, 110 ± 25, and 60 ± 17 kd as analyzed by electrophoresis under reducing conditions.