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Receptor‐operated Ca 2+ entry mediated by TRPC3/TRPC6 proteins in rat prostate smooth muscle (PS1) cell line
Author(s) -
Thebault S.,
Zholos A.,
Enfissi A.,
Slomianny C.,
Dewailly E.,
Roudbaraki M.,
Parys J.,
Prevarskaya Natalia
Publication year - 2005
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.20301
Subject(s) - trpc3 , trpc6 , microbiology and biotechnology , receptor , smooth muscle , cell culture , prostate , medicine , chemistry , endocrinology , biology , trpc , biochemistry , transient receptor potential channel , genetics , cancer
Prostate smooth muscle cells predominantly express α1‐adrenoceptors (α1‐AR). α1‐AR antagonists induce prostate smooth muscle relaxation and therefore they are useful therapeutic compounds for the treatment of benign prostatic hyperplasia symptoms. However, the Ca 2+ entry pathways associated with the activation of α1‐AR in the prostate have yet to be elucidated. In many cell types, mammalian homologues of transient receptor potential ( TRP ) genes, first identified in Drosophila , encode TRPC (canonical TRP) proteins. They function as receptor‐operated channels (ROCs) which are involved in various physiological processes such as contraction, proliferation, apoptosis, and differentiation. To date, the expression and function of TRPC channels have not been studied in prostate smooth muscle. In fura‐2 loaded PS1 (a prostate smooth muscle cell line) which express endogenous α1A‐ARs, α‐agonists epinephrine (EPI), and phenylephrine (PHE) induced Ca 2+ influx which depended on the extracellular Ca 2+ and PLC activation but was independent of PKC activation. Thus, we have tested two membrane‐permeable analogues of diacylglycerol (DAG), oleoyl‐acyl‐ sn ‐glycerol (OAG) and 1,2‐dioctanoyl‐ sn ‐glycerol (DOG). They initiated Ca 2+ influx whose properties were similar to those induced by the α‐agonists. Sensitivity to 2‐aminoethyl diphenylborate (2‐APB), SKF‐96365 and flufenamate implies that Ca 2+ ‐permeable channels mediated both α‐agonist‐ and OAG‐evoked Ca 2+ influx. Following the sarcoplasmic reticulum (SR) Ca 2+ store depletion by thapsigargin (Tg), a SERCA inhibitor, OAG and PHE were both still able to activate Ca 2+ influx. However, OAG failed to enhance Ca 2+ influx when added in the presence of an α‐agonist. RT‐PCR and Western blotting performed on PS1 cells revealed the presence of mRNAs and the corresponding TRPC3 and TRPC6 proteins. Experiments using an antisense strategy showed that both α‐agonist‐ and OAG‐induced Ca 2+ influx required TRPC3 and TRPC6, whereas the Tg‐activated (“capacitative”) Ca 2+ entry involved only TRPC3 encoded protein. It may be thus concluded that PS1 cells express TRPC3 and TRPC6 proteins which function as receptor‐ and store‐operated Ca 2+ entry pathways. © 2005 Wiley‐Liss, Inc.