ABSTRACT
OBJECTIVE: To investigate the effects of ursolic acid (UA) on T-cell proliferation and activation, as well as to examine its effect on nuclear factor-κB (NF-κB) signaling pathway in T cells. METHODS: T-cells isolated from BALB/c mice were incubated with UA at concentrations ranging from 5-30 µmol/L in the presence of phorbol 12-myristate 13-acetate (PMA) or PMA plus ionomycin. The proliferation of T cells was measured by the MTT assay. The expressions of CD69, CD25, and CD71 on T-cell surface were analyzed using flow cytometry. The level of interleukin-2 (IL-2) in the culture supernatant of activated T cells was quantified by enzyme-linked immunosorbent assay (ELISA). The level of phosphorylated IκB-α (p-IκB-α) in total protein and p65, a subunit of NF-κB, nuclear translocation were measured by Western blot analysis. RESULTS: UA in a dose-dependent manner significantly decreased the proliferation and inhibited the surface expressions of CD69, CD25, and CD71 in murine T lymphocytes upon in vitro activation (P<0.01). Significant reduction of IL-2 production was found in activated T cells treated with UA (P<0.01). The PMA-induced increase in p-IκB-α protein was inhibited, and nuclear translocation of p65 from the cytoplasm was blocked by UA. CONCLUSION: UA is a potent inhibitor for T cell activation and proliferation; these effects are associated with the inhibition of NF-κB signaling pathway.
Subject(s)
Lymphocyte Activation/drug effects , NF-kappa B/metabolism , Signal Transduction/drug effects , T-Lymphocytes/cytology , T-Lymphocytes/immunology , Triterpenes/pharmacology , Animals , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Cell Proliferation/drug effects , I-kappa B Proteins/metabolism , Interleukin-2/metabolism , Ionomycin/pharmacology , Mice , Mice, Inbred BALB C , NF-KappaB Inhibitor alpha , Phosphorylation/drug effects , Protein Transport/drug effects , T-Lymphocytes/drug effects , T-Lymphocytes/metabolism , Tetradecanoylphorbol Acetate/pharmacology , Ursolic AcidABSTRACT
Parkinson's disease (PD) is associated with mitochondrial dysfunction, oxidative stress, and activation of the apoptotic cascade. In the study, we investigated the effects of salvianolic acid B (Sal B) on 1-methyl-4-phenylpyridinium (MPP(+))-treated SH-SY5Y cells, a classic in vitro model for PD. We found Sal B inhibited the loss of cell viability by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The underlying mechanisms of Sal B action were further studied. Treatment of SH-SY5Y cells with MPP(+) caused a loss of cell viability and mitochondrial membrane potential, condensation of nuclei, elevation in the level of reactive oxygen species (which was associated with cytochrome c release), an increase in the Bax/Bcl-2 mRNA ratio, and activation of caspase-3. Sal B ameliorated the MPP(+)-altered phenotypes. These results indicate that the Sal B protected SH-SY5Y cells against MPP(+)-induced apoptosis by relieving oxidative stress and modulating the apoptotic process. Our findings suggest that salvianolic acid B may be a promising agent to prevent PD.
