Protein kinase C{gamma} mediates regulation of proliferation by the serotonin 5-hydroxytryptamine receptor 2B.
Activation of the 5-hydroxytryptamine receptor 2B (5-HT(2B)), a G(q/11) protein-coupled receptor, results in proliferation of various cell types. The 5-HT(2B) receptor is also expressed on the pacemaker cells of the gastrointestinal tract, the interstitial cells of Cajal (ICC), where activation triggers ICC proliferation. The goal of this study was to characterize the mitogenic signal transduction cascade activated by the 5-HT(2B) receptor. All of the experiments were performed on mouse small intestine primary cell cultures. Activation of the 5-HT(2B) receptor by its agonist BW723C86 induced proliferation of ICC. Inhibition of phosphatidylinositol 3-kinase by LY294002 decreased base-line proliferation but had no effect on 5-HT(2B) receptor-mediated proliferation. Proliferation of ICC through the 5-HT(2B) receptor was inhibited by the phospholipase C inhibitor U73122 and by the inositol 1,4,5-trisphosphate receptor inhibitor Xestospongin C. Calphostin C, the alpha, beta, gamma, and micro protein kinase C (PKC) inhibitor Gö6976, and the alpha, beta, gamma, delta, and zeta PKC inhibitor Gö6983 inhibited 5-HT(2B) receptor-mediated proliferation, indicating the involvement of PKC alpha, beta, or gamma. Of all the PKC isoforms blocked by Gö6976, PKCgamma and micro mRNAs were found by single-cell PCR to be expressed in ICC. 5-HT(2B) receptor activation in primary cell cultures obtained from PKCgamma(-/-) mice did not result in a proliferative response, further indicating the requirement for PKCgamma in the proliferative response to 5-HT(2B) receptor activation. The data demonstrate that the 5-HT(2B) receptor-induced proliferative response of ICC is through phospholipase C, [Ca(2+)](i), and PKCgamma, implicating this PKC isoform in the regulation of cellular proliferation.
Wouters
Mira M
MM
Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Miles and Shirley Fiterman Center for Digestive Diseases, Rochester, Minnesota 55905, USA.
Roeder
Jaime L
JL
Tharayil
Vivek S
VS
Stanich
Jennifer E
JE
Strege
Peter R
PR
Lei
Sha
S
Bardsley
Michael R
MR
Ordog
Tamas
T
Gibbons
Simon J
SJ
Farrugia
Gianrico
G
D000818:Animals; D002867:Chromones / Q000494:pharmacology; D020541:Coiled Bodies / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D047028:Macrocyclic Compounds / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009025:Morpholines / Q000494:pharmacology; D010080:Oxazoles / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D011760:Pyrrolidinones / Q000494:pharmacology; D044403:Receptor, Serotonin, 5-HT2B / Q000096:biosynthesis*; D013876:Thiophenes / Q000494:pharmacology
C092430:1-(5-(2-thenyloxy)-1H-indol-3-yl)propan-2-amine; D002867:Chromones; D004791:Enzyme Inhibitors; D004963:Estrenes; D007211:Indoles; D047028:Macrocyclic Compounds; D009025:Morpholines; D010080:Oxazoles; D011760:Pyrrolidinones; D044403:Receptor, Serotonin, 5-HT2B; D013876:Thiophenes; C511704:xestospongin C; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; C087857:protein kinase C gamma; D011493:Protein Kinase C