RESUMO
The increase in cytoplasmic Ca(2+) concentration (Δ[Ca(2+)](c)) mediated by the Ca(2+)-release-activated Ca(2+) channel (CRAC) is a critical signal for the activation of lymphocytes. Also, the voltage-gated K(+) channel (K(v)) and intermediate-conductance Ca(2+)-activated K(+) channel (IKCa1/SK4) have drawn attention as pharmacological targets for regulating immune responses. Since polyphenolic agents have various immunomodulatory effects, here we compared the effects of curcumin, rosmarinic acid, resveratrol, and epigallocatechin gallate on the ionic currents through CRAC (I(CRAC)), K(v) (I(Kv)), SK4 (I(SK4)) and on the Δ[Ca(2+)](c) of Jurkat-T cells using the patch clamp technique and fura-2 spectrofluorimetry. Curcumin (10 µM) inhibited store-operated Ca(2+) entry (SOCE). Consistently, dose-dependent inhibition of I(CRAC) by curcumin was confirmed in Jurkat-T (IC(50), 5.9 µM) and the HEK293 cells overexpressing Orai1 and STIM1 (IC(50), 0.6 µM). Also, curcumin inhibited both I(Kv) (IC(50), 11.9 µM) and I(SK4) (IC(50), 4.2 µM). The other polyphenols (rosmarinic acid, resveratrol, and epigallocatechin gallate at 10 - 30 µM) had no effect on SOCE and showed only a partial inhibition of the K(+) currents. In summary, among the tested polyphenolic agents, curcumin showed prominent inhibition of major ion channels in lymphocytes, which might contribute to the anti-inflammatory effects of curcumin. [Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.10209FP].
Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/metabolismo , Curcumina/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/metabolismo , Cálcio/metabolismo , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Flavonoides/farmacologia , Células HEK293 , Humanos , Células Jurkat , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/metabolismo , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/metabolismo , Proteína ORAI1 , Técnicas de Patch-Clamp , Fenóis/farmacologia , Polifenóis , Molécula 1 de Interação EstromalRESUMO
The increase in cytoplasmic Ca2+ concentration (Δ[Ca2+]c) mediated by the Ca2+-release-activated Ca2+ channel (CRAC) is a critical signal for the activation of lymphocytes. Also, the voltage-gated K+ channel (Kv) and intermediate-conductance Ca2+-activated K+ channel (IKCa1/SK4) have drawn attention as pharmacological targets for regulating immune responses. Since polyphenolic agents have various immunomodulatory effects, here we compared the effects of curcumin, rosmarinic acid, resveratrol, and epigallocatechin gallate on the ionic currents through CRAC (ICRAC), Kv (IKv), SK4 (ISK4) and on the Δ[Ca2+]c of Jurkat-T cells using the patch clamp technique and fura-2 spectrofluorimetry. Curcumin (10 µM) inhibited store-operated Ca2+ entry (SOCE). Consistently, dose-dependent inhibition of ICRAC by curcumin was confirmed in Jurkat-T (IC50, 5.9 µM) and the HEK293 cells overexpressing Orai1 and STIM1 (IC50, 0.6 µM). Also, curcumin inhibited both IKv (IC50, 11.9 µM) and ISK4 (IC50, 4.2 µM). The other polyphenols (rosmarinic acid, resveratrol, and epigallocatechin gallate at 10 - 30 µM) had no effect on SOCE and showed only a partial inhibition of the K+ currents. In summary, among the tested polyphenolic agents, curcumin showed prominent inhibition of major ion channels in lymphocytes, which might contribute to the anti-inflammatory effects of curcumin. [Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.10209FP].