Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013:3:2553.
doi: 10.1038/srep02553.

The flavonoid apigenin improves glucose tolerance through inhibition of microRNA maturation in miRNA103 transgenic mice

Motoko Ohno  1 , Chikako Shibata, Takahiro Kishikawa, Takeshi Yoshikawa, Akemi Takata, Kentaro Kojima, Masao Akanuma, Young Jun Kang, Haruhiko Yoshida, Motoyuki Otsuka, Kazuhiko Koike
Affiliations

The flavonoid apigenin improves glucose tolerance through inhibition of microRNA maturation in miRNA103 transgenic mice

Motoko Ohno et al. Sci Rep. 2013.

Abstract

Polyphenols are representative bioactive substances with diverse biological effects. Here, we show that apigenin, a flavonoid, has suppressive effects on microRNA (miRNA) function. The effects were mediated by impaired maturation of a subset of miRNAs, probably through inhibition of the phosphorylation of TRBP, a component of miRNA-generating complexes via impaired mitogen-activated protein kinase (MAPK) Erk activation. While glucose intolerance was observed in miRNA103 (miR103)-overexpressing transgenic mice, administration of apigenin improved this pathogenic status likely through suppression of matured miR103 expression levels. These results suggest that apigenin may have favorable effects on the pathogenic status induced by overexpression of miRNA103, whose maturation is mediated by phosphorylated TRBP.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Apigenin inhibits miRNA function.
(a), Apigenin inhibits endogenous miRNA function. Huh7 cells were transfected with reporters to determine the functions of the indicated miRNAs. Twenty-four hours after treatment with the indicated substances, reporter assays were performed. Data represent the means ± standard deviation (s.d.) from three independent experiments. *, p < 0.05 (t-test). (b), Apigenin inhibits the function of exogenously overexpressed miRNAs. Huh7 cells were transfected with reporters and corresponding miRNA precursor-expressing plasmids or an empty vector. Twenty-four hours after treatment with the indicated substances, reporter assays were performed. Data represent the means ± s.d. from three independent experiments. *, p < 0.05 (t-test). (c), Dose-dependent effects of apigenin on miRNA function. Huh7 cells were transfected with reporter plasmids to determine miR122 function. Cells were treated with indicated doses of apigenin for 24 h and luciferase assays were performed. Caffeine was included as a negative control. Data represent the means ± s.d. from three independent experiments. *, p < 0.05 (t-test) compared with the negative control.
Figure 2
Figure 2. Apigenin impairs miRNA maturation.
(a), Cells were treated with the appropriate substances for 24 h and the indicated proteins were blotted. Representative results from three independent experiments using Huh7 cells are shown. Full-length blot images are available in Supplementary Figure 5a. (b), The expression levels of mature miRNAs and miRNA precursors were determined by qRT-PCR using Huh7 cells with or without apigenin treatment for 24 h. Data represent the means ± s.d. from three independent experiments. *, p < 0.05 (t-test) compared with the control (DMSO only) treatment.
Figure 3
Figure 3. Apigenin inhibits TRBP phosphorylation.
(a), Cells were treated with caffeine or apigenin for 24 h. Cell lysates were blotted with anti-phosphorylated Erk and anti-total Erk1/2. Representative results from three independent experiments using Huh7 cells are shown. Similar results were obtained using Hep3B cells. (b), A luciferase assay was performed to determine SRE-driven transcription under apigenin treatment. Caffeine was included as a comparison. Data represent the means ± s.d. from three independent experiments using Huh7 cells. *, p < 0.05 (t-test) compared to the negative control. (c), Huh7 cells were transfected with wild-type TRBP-expressing plasmids followed by treatment with the indicated substances for 24 h. Serine-to-alanine mutant TRBP (SΔA) indicates non-phosphorylated TRBP. Representative results from three independent experiments using Huh7 cells are shown. (d), Substance-treated Huh7 cell lysates were separated using a Mn2+-Phos-tag gel to discriminate the phosphorylated form of TRBP. Representative results from three independent experiments using Huh7 cells are shown. (e), TRBP-expressing Huh7 cells were stably transfected with myc-tagged CA-MEK-expressing plasmids followed by apigenin treatment for 24 h. Phosphorylation status of TRBP was determined by Western blotting. Representative results from three independent experiments are shown. (f), Huh7 cells were stably transfected with myc-tagged CA-MEK-expressing plasmids or myc-tagged DN-Erk-expressing plasmids. The expression of the transfected constructs was confirmed by Western blotting using anti-myc antibodies (left panels). Expression levels of mature miRNAs in those cells with or without apigenin treatment were determined by Northern blotting (right panels). Representative results of at least three independent experiments are shown. Full-length blot images in a, b, c, d, e, and f are available in Supplementary Figure 5b, c, d, e, and f.
Figure 4
Figure 4. Apigenin improves glucose tolerance in miR103 transgenic mice.
(a), Expression levels of mature miR103, miR122, and miR185 in liver tissues of miR103 transgenic mice (miR103 Tg) were determined by Northern blotting. (b), Expression levels of mature miR103 and its precursor in liver tissues of miR10-transgenic mice treated with apigenin were determined by Northern blotting. Control (DMSO) or apigenin (40 mg/kg) was injected intraperitoneally daily for 14 days. Representative results from three independent mouse sets are shown. (c), Liver tissue homogenates from miR103 transgenic mice were separated using a phos-tag gel to determine the phosphorylation status of TRBP. Representative results from three independent mouse sets are shown. Full-length blot image is available in Supplementary Figure 5g. (d), Blood glucose levels were determined at random times or after 12 h fasting in control and miR103 transgenic (miR103 Tg) mice (n = 8 in each group). Data represent the means ± s.d. *, p < 0.05 (t-test). (e), (f), Glucose and pyruvate tolerance tests in control, miR103 transgenic (miR103 Tg), and miR103 transgenic with apigenin treatment (miR103 Tg + apigenin) mice (n = 6 in each group). Data represent the means ± s.d. *, p < 0.05 (t-test).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Surh Y. J. Cancer chemoprevention with dietary phytochemicals. Nat Rev Cancer 3, 768–780 (2003). - PubMed
    1. D'Incalci M., Steward W. P. & Gescher A. J. Use of cancer chemopreventive phytochemicals as antineoplastic agents. Lancet Oncol 6, 899–904 (2005). - PubMed
    1. Baur J. A. et al. Resveratrol improves health and survival of mice on a high-calorie diet. Nature 444, 337–342 (2006). - PMC - PubMed
    1. Carrington J. & Ambros V. Role of microRNAs in plant and animal development. Science 301, 336–338 (2003). - PubMed
    1. Bartel D. P. MicroRNAs: genomics, biogenesis, mechanism, and function. Cell 116, 281–297 (2004). - PubMed

Publication types

-