Increase in Ca2+ current by sustained cAMP levels enhances proliferation rate in GH3 cells

LIFE SCIENCES

卷:192

Article

Rodrigues, Andreia Laura¹  Brescia, Marcella³  Koschinski, Andreas³  Moreira, Thais Helena⁴  Cameron, Ryan T.²  Baillie, George²  Beirao, Paulo S. L.⁴  Zaccolo, Manuela³  Cruz, Jader S.⁴ 

[1] Univ FUMEC, Lab CaCIA, Fac Ciencias Humanas Sociais & Saude, Belo Horizonte, MG, Brazil

[2] Glasgow Univ, Inst Cardiovasc & Med Sci, Glasgow, Lanark, Scotland

[3] Univ Oxford, Dept Physiol Anat & Genet, Oxford, England

[4] Univ Fed Minas Gerais, Lab Membranas Excitaveis & Biol Cardiovasc, Dept Bioquim & Imunol, Inst Ciencias Biol, Belo Horizonte, MG, Brazil

关键词: Patch-clamp;    FRET-imaging;    cAMP;    Forskolin;    Ca2+ channels;    Cell proliferation;   

DOI  :  10.1016/j.lfs.2017.11.040

来源: Elsevier

【 摘 要 】

Aims: Ca2+ and cAMP are important intracellular modulators. In order to generate intracellular signals with various amplitudes, as well as different temporal and spatial properties, a tightly and precise control of these modulators in intracellular compartments is necessary. The aim of this study was to evaluate the effects of elevated and sustained cAMP levels on voltage-dependent Ca2+ currents and proliferation in pituitary tumor GH3 cells. Main methods: Effect of long-term exposure to forskolin and dibutyryl-cyclic AMP (dbcAMP) on Ca2+ current density and cell proliferation rate were determined by using the whole-cell patch-clamp technique and real time cell monitoring system. The cAMP levels were assayed, after exposing transfected GH3 cells with the EPAC-1 cAMP sensor to forskolin and dbcAMP, by FRET analysis. Key findings: Sustained forskolin treatment (24 and 48 h) induced a significant increase in total Ca2+ current density in GH3 cells. Accordingly, dibutyryl-cAMP incubation (dbcAMP) also elicited increase in Ca2+ current density. However, the maximum effect of dbcAMP occurred only after 72 h incubation, whereas forskolin showed maximal effect at 48 h. FRET-experiments confirmed that the time-course to elevate intracellular cAMP was distinct between forskolin and dbcAMP. Mibefradil inhibited the fast inactivating current component selectively, indicating the recruitment of T-type Ca2+ channels. A significant increase on cell proliferation rate, which could be related to the elevated and sustained intracellular levels of cAMP was observed. Significance: We conclude that maintaining high levels of intracellular cAMP will cause an increase in Ca2+ current density and this phenomenon impacts proliferation rate in GH3 cells.

【 授权许可】

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