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Mol Cell Biochem. 2018 Oct;447(1-2):21-32. doi: 10.1007/s11010-018-3290-3. Epub 2018 Jan 23.

Berberine activates bitter taste responses of enteroendocrine STC-1 cells.

Author information

1
Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, People's Republic of China.
2
Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, People's Republic of China. dsdu@shu.edu.cn.
3
Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, People's Republic of China. chenfuxue@staff.shu.edu.cn.

Abstract

Glucagon-like peptide-1 (GLP-1) is involved in the regulation of insulin secretion and glucose homeostasis. GLP-1 release is stimulated when berberine interacts with a novel G protein family (TAS2Rs) in enteroendocrine cells. In this study, we used STC-1 cells and examined a marked increase in Ca2+ in response to various bitter compounds. Ca2+ responses to traditional Chinese medicine extracts, including berberine, phellodendrine and coptisine, in STC-1 cells were suppressed by the phospholipase C (PLC) inhibitor U-73122, suggesting the involvement of bitter taste receptors in changing the physiological status of enteroendocrine cells in a PLC-dependent manner. STC-1 cells showed berberine-up-regulated preproglucagon (GLP-1 precursor) mRNA and GLP-1 secretion. A QPCR analysis demonstrated that TAS2R38, a subtype of the bitter taste receptor, was associated with GLP-1 secretion. Berberine-mediated GLP-1 secretion was attenuated in response to small interfering RNA silencing of TAS2R38. The current studies demonstrated that Gα-gustducin co-localized with GLP-1 and Tas2r106 in the STC-1 cells. We further utilized inhibitors of PLC and TRPM5, which are known to participate in taste signal transduction, to investigate the underlying pathways mediated in berberine-induced GLP-1 secretion. Berberine-induced GLP-1 release from enteroendocrine cells is modulated in a PLC-dependent manner through a process involving the activation of bitter taste receptors. Together, our data demonstrated a berberine-mediated GLP-1 secretion pathway in mouse enteroendocrine cells that could be of therapeutic relevance to hyperglycemia and the role of bitter taste receptors in the function of the small intestine.

KEYWORDS:

Alkaloid; Bitter taste receptors; Glucagon-like peptide 1; Insulin secretion; STC-1 cells

PMID:
29363059
DOI:
10.1007/s11010-018-3290-3
[Indexed for MEDLINE]

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