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Somatostatin increases mitogen‐induced IL‐2 secretion and proliferation of human jurkat T cells via sst3 receptor isotype
Author(s) -
Cardoso Alicia,
El Ghamrawy Christelle,
Gautron JeanPierre,
Horvat Branka,
Gautier Nicole,
Enjalbert Alain,
Krantic Slavica
Publication year - 1998
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19980101)68:1<62::aid-jcb6>3.0.co;2-u
Subject(s) - jurkat cells , somatostatin , adenylyl cyclase , somatostatin receptor , receptor , medicine , biology , endocrinology , second messenger system , neuropeptide y receptor , chemistry , t cell , neuropeptide , biochemistry , immunology , immune system
The neuropeptide somatostatin (SRIF) modulates normal and leukemia T cell proliferation. However, neither molecular isotypes of receptors nor mechanisms involved in these somatostatin actions have been elucidated as yet. Here we show by using RT‐PCR approach that mitogen‐activated leukemia T cells (Jurkat) express mRNA for a single somatostatin receptor, sst3. This mRNA is apparently translated into protein since specific somatostatin binding sites (K I1 = 78 ± 3 pM) were detected in semipurified plasma membrane preparations by using 125 I‐Tyr 1 ‐SRIF14 as a radioligand. Moreover, somatostatin inhibits adenylyl cyclase activity with similar efficiency (IC 50 = 23 ± 4 pM) thus strongly suggesting a functional coupling of sst3 receptor to this transduction pathway. The involvement of sst3 receptor in immuno‐modulatory actions of somatostatin was assessed by analysis of neuropeptide effects on IL‐2 secretion and on proliferation of mitogen‐activated Jurkat cells. Our data show that in the concentrations comprised between 10 pM and 10 nM, somatostatin potentiates IL‐2 secretion. This effect is correlated with somatostatin‐dependent increase of Jurkat cell proliferation since the EC 50 concentrations for both actions were almost identical (EC 50 = 22 ± 9 pM and EC 50 = 12 ± 1 pM for IL‐2 secretion and proliferation, respectively). Altogether, these data strongly suggest that in mitogen‐activated Jurkat cells, somatostatin increases cell proliferation through the increase of IL‐2 secretion via a functional sst3 receptor negatively coupled to the adenylyl cyclase pathway. J. Cell. Biochem. 68:62–73, 1998. © 1998 Wiley‐Liss, Inc.