Heptamethoxyflavone Reduces Phosphodiesterase Activity and T-Cell Growth in vitro
Yui Hamada1, Mitsunari Nakajima, Kazuna Tsuzuki
1Department of Pharmaceutical Pharmacology, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Japan.
Abstract:
In a previous study, we reported that interleukin-4 production was reduced in spleen cells of mice administered 3,5,6,7,8,3',4'-heptamethoxyflavone (HMF), which is a polymethoxyflavone found at high concentrations in the peel of various citrus fruits. In this study, we investigated the function of HMF on the growth of T cells cultured from the spleens of mice. HMF decreased the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by anti-CD3/CD28 antibody-stimulated mouse spleen cells. HMF inhibited the activities of phosphodiesterase (PDE) enzymes prepared from bovine brain and human PDE4B and PDE3B enzymes. The cyclic AMP (cAMP) content in anti-CD3/CD28 antibody-stimulated spleen cells increased after HMF treatment in vitro. These results suggest that HMF inhibits T-cell growth and affects immune function via reduced PDE activity and increased cAMP content.
Insights
3,5,6,7,8,3
Area of Science:
- Immunology
- Pharmacology
Background:
- 3,5,6,7,8,3',4'-heptamethoxyflavone (HMF), a citrus fruit polymethoxyflavone, was previously shown to reduce interleukin-4 production.
- T cells play a crucial role in immune function.
Purpose of the Study:
- To investigate the effects of HMF on T-cell growth and immune function in mice.
- To elucidate the molecular mechanisms underlying HMF's action on T cells.
Main Methods:
- Mouse spleen cells were cultured and stimulated with anti-CD3/CD28 antibodies.
- Cell viability was assessed using the MTT assay.
- Phosphodiesterase (PDE) enzyme activity was measured.
- Intracellular cyclic AMP (cAMP) levels were quantified.
Main Results:
- HMF treatment inhibited T-cell proliferation, as indicated by reduced MTT reduction.
- HMF inhibited both bovine brain and human PDE4B and PDE3B enzyme activities.
- HMF treatment led to increased intracellular cAMP levels in stimulated T cells.
Conclusions:
- HMF exhibits inhibitory effects on T-cell growth.
- HMF modulates immune function by inhibiting PDE activity and increasing cAMP levels.
