Objective: The activation of T lymphocytes contributes to the inflammatory process of atherosclerosis. Here we examined the effects of carvedilol, a new beta-blocker containing an antioxidative property, on the activation of T cells.
Methods: Human peripheral blood T cells were negatively selected from whole blood. Cytokines were measured by ELISA. The NF-kappaB and related protein activity was determined by electrophoretic mobility shift assays, Western blotting, kinase assays and transfection assays.
Results: Carvedilol was nontoxic at concentrations </=10 microM, however, higher dosages (>/=20 microM) induced T cell apoptosis. We demonstrated that carvedilol inhibited cytokine production from various stimuli-activated T cells. Carvedilol also suppressed the expression of T cell activation markers, including CD25, CD69 and CD71. Molecular investigation indicated that carvedilol specifically downregulated NF-kappaB but not activator protein 1 DNA-binding activity in activated T cells. The inhibitory effect was likely due to its antioxidative property. Meanwhile, carvedilol prevented stimuli-induced IkappaBalpha degradation. Such an effect was mediated through the inhibition of IkappaBalpha kinase activity. The inhibitory specificity on NF-kappaB by carvedilol was also demonstrated in transfection assays.
Conclusions: Our results demonstrated a novel therapeutic mechanism of carvedilol in atherosclerosis, namely the inhibition of T cell activation via downregulating NF-kappaB activity.