Kang-Hoon Kim

Coix seed extract attenuates the high-fat induced mouse obesity via PPARγ and C/EBPα a downregulation

The seed of the Coix lacryma-jobi L. var. ma-yuen Stapf seed (CLMS) extract has been prescribed to alleviate obesity by practitioners of traditional Korean medicine. Here, we investigated the effect of CLMS extract on PPARγ2 and c/EBPα and obesity responses in C57BL/6J obese mice fed on a high fat diet. The mouse body index, blood profile, and fat accumulation levels in the liver were measured. The protein expression levels of PPARγ2 and c/EBPα in the mice livers were also measured to determine the molecular mode-of-action of the reducing effect of CLMS extract on mouse adipogenesis. The results showed that HFD-induced mouse obesity, fat accumulation, and serum cholesterol were alleviated by the CLMS extract addition. Moreover, PPARγ2 and C/EBPα, proteins, those are related to the adipogenesis, were downregulated by the CLMS extract intake considerably. This study indicates that as a food additive, CLMS extract has a reducing effect on the high-fat diet induced fat accumulation and on body weight through the downregulation of adipogenesis.

The aglycone of ginsenoside Rg3 enables glucagon-like peptide-1 secretion in enteroendocrine cells and alleviates hyperglycemia in type 2 diabetic mice

Ginsenosides can be classified on the basis of the skeleton of their aglycones. Here, we hypothesized that the sugar moieties attached to the dammarane backbone enable binding of the ginsenosides to the sweet taste receptor, eliciting glucagon-like peptide-1 (GLP-1) secretion in the enteroendocrine L cells. Using the human enteroendocrine NCI-H716 cells, we demonstrated that 15 ginsenosides stimulate GLP-1 secretion according to the position of their sugar moieties. Through a pharmacological approach and RNA interference technique to inhibit the cellular signal cascade and using the Gαgust−/− mice, we elucidated that GLP-1 secreting effect of Rg3 mediated by the sweet taste receptor mediated the signaling pathway. Rg3, a ginsenoside metabolite that transformed the structure through a steaming process, showed the strongest GLP-1 secreting effects in NCI-H716 cells and also showed an anti-hyperglycemic effect on a type 2 diabetic mouse model through increased plasma GLP-1 and plasma insulin levels during an oral glucose tolerance test. Our study reveals a novel mechanism where the sugar moieties of ginsenosides Rg3 stimulates GLP-1 secretion in enteroendocrine L cells through a sweet taste receptor-mediated signal transduction pathway and thus has an anti-hyperglycemic effect on the type 2 diabetic mouse model.

Transcriptomic analysis of the bitter taste receptor-mediated glucagon-like peptide-1 stimulation effect of quinine

Quinine is a bitter taste receptor agonist that has been studied its anti-pyretic, anti-malarial, anti-pain, and anti-inflammatory activity. In this study, glucagon-like peptide-1 (GLP-1) stimulation effect of quinine was investigated. Bitter taste receptors are G protein-coupled receptor (GPCR), which transfer the molecular signal through its downstream cascade. The activation of bitter taste receptor, which expressed in the enteroendocrine L cells, stimulates the GLP-1 secretion and therefore can be a therapeutic target of the type-2 diabetes mellitus (T2DM). Here, we studied GLP-1 stimulation effect of quinine on the endocrine differentiated NCI-H716 cells. To investigate the molecular mode-of-action of the GLP-1 stimulation effect of quinine in the enteroendocrine L cells, transcriptomic analysis was performed. Our data suggest that quinine stimulates the GLP-1 secretion through the bitter taste receptor-signaling pathway, and thus has the possibility of therapeutic agent of T2DM.

Aqueous extracts of Anemarrhena asphodeloides stimulate glucagon-like pepetide-1 secretion in enteroendocrine NCI-H716 cells

Anemarrhena asphodeloides (AA), a bitter taste herbal medicine, has been prescribed in traditional oriental medicine to treat diabetes mellitus. Here, AA was extracted and fractionated to investigate its effects on the stimulation of glucagon-like peptide-1 (GLP-1) secretion in enteroendocrine cells. GLP-1 is secreted from the human enteroendocrine L cells to the blood in response to ingested nutrients. Because GLP-1 increases glucose dependent insulin release, it is known as a therapeutic method for the treatment of type II diabetes mellitus. The human enteroendocrine L cell line NCI-H716 expresses various chemoreceptors including the G protein coupled receptor (GPCR). Previous studies suggested that, through the GPCR signaling pathway, the secretion of GLP-1 can be induced in NCI-H716. Accordingly, we studied the GLP-1 stimulation effect of the AA extract and its mode-of-action using the GLP-1 ELISA and microarray. Functional categorization of the microarray data confirmed up or down-regulated gene expressions associated with the GPCR signaling pathway. This study demonstrates that AA extracts have a scientific possibility as a GLP-1 stimulant and thus may have the potential to be a therapeutic herbal medicine for type II diabetes mellitus.

Isolated protein of Astragalus membranaceus acts as an allergen by binding human immunoglobulin E on human sera

Allergy is nearly always triggered by protein molecules and the majority of individuals with documented immunologic reaction to foods or plants IgE reactions. However, proteins derived from herbal medicine act as an allergen is unknown. In this study, we aimed to confirm if herbal medicine, Astragalus membranaceus, at proteomic level may contain to trigger the immunoreactivity of IgE. If it does, what components of protein molecules in herbal medicine, Astragalus membranaceus, is react to a binding IgE. In order to resolve this hypothesis, we performed proteomic tools, SDS-PAGE stained coomassie blue and identified protein by LC-MS/MS. Also, we tested plasma IgE reactivity on an isolated protein of Astragalus membranaceus using western blot of human IgE and enzyme immunoassay panel, Allergy-Q test in 400 patients. Through the described performances, we could select four sera of positive candidate and identify Astragalus membranaceus IgE binding proteins. Our data suggested that herbal medicine, Astragalus membranaceus was possible to act an allergen by identify IgE binding protein with isolated protein of Astragalus membranaceus.

The anti-inflammatory effects of Alisma herb extract on allergic asthma mouse model

Asthma is a complex chronic inflammatory disorder in the airway accompanying airway hyperresponsiveness, airway obstruction and airway wall remodeling. Alisma canaliculatum (AC) is a constituent of Cheong-Sang-Bo-Ha-Tang (CSBHT) which had been frequently prescribed to treat the respiratory disease in traditional Korean medicine. Here, we investigated the precise mechanism of the anti-inflammatory activity of AC extract using ovalbumin-induced mouse asthma model. AC extract administration improved the mouse AHR, and alleviated the thickened airway epithelium. These effects may mediate by the inhibitory effect of AC extract on nuclear factor kappa B (NF-κB) activation. And the inhibitory effect regulated the inducible nitric oxide synthase (iNOS) expression at the transcription level. We determined the AC extract metabolites through UPLC/ESI-QTOF-MS and identified 10-O-methyl-alismoxide, 11-deoxyalisol C, 4-12-dihydroxyguaian-6,10-diene, alismol, alismoxide, alisol B, alisol B 23-acetate, alisol C 23-acetate, and alisolide. This study provides the full understanding about the anti-asthmatic effect of AC extract for the first time.

Development of GLP-1 secretagogue using microarray in enteroendocrine L cells

Glucagon-like peptide-1 (GLP-1) plays glucose homeostasis and delays gastric empty. Because GLP-1 activates GLP-1 receptor and this activation recruits insulin secretion in pancreatic β-cells. This biological action applied therapeutic treatment for type 2 diabetes mellitus using GLP-1 analogues, exendin-4 and lilaglutide. Although therapeutic approaches of GLP-1 analogues are very effective as a hypoglycemic agents, its side effects are occurred in clinical study such as pancreatitis, autoimmune hepatitis and acute kidney injury. To solve critical side effects in therapeutic treatment, alternative ways are still developed. In this review, we introduce the character of taste receptors and taste receptor signaling. Because taste receptors and taste receptor signaling are able to induce GLP-1 release from exogenous molecules in enteroendocrine L cells. And how we find and develop that safe exogenous molecules to induce GLP-1 are in natural resources against side effects. We suggest that mRNA variants of taste receptors and taste receptor signaling molecules are briefly screening to find GLP-1 secret-agogue in natural components including herbal medicines using biochip in enteroendocrine L cells.

GLP-1 secretion is stimulated by 1,10-phenanthroline via colocalized T2R5 signal transduction in human enteroendocrine L cell

Glucagon-like peptide-1 (GLP-1) hormone is known to regulate blood glucose by an insulinotropic effect and increases proliferation as and also prevents apoptosis of pancreatic β cells. We know that GLP-1 is secreted by nutrients such as fatty acids and sweet compounds but also bitter compounds via stimulation of G-protein coupled receptors (GPCRs) in the gut. Among these, bitter compounds are multiply-contained in phytochemicals or artificial materials and perceived as ligands of various bitter taste receptors. We hypothesized that GLP-1 hormone is secreted through stimulation of a single bitter taste receptor by 1,10-phenanthroline which is known agonist of taste receptor type 2 member 5 (T2R5). To prove this hypothesis, we used the representatively well-known 1,10-phenanthroline as ligand of single receptor and evaluated the existence of T2R5 by double-labeling immunofluorescence and then 1,10-phenanthroline is able to secrete GLP-1 hormone through stimulation of T2R5 in human enteroendocrine cells. Consequently, we verify that GLP-1 hormone is colocalized with T2R5 in the human duodenum and ileum tissue and is secreted by 1,10-phenanthroline via T2R5 signal transduction in differentiated human enteroendocrine L cells.

Hexane Fractions of Bupleurum falcatum L. Stimulates Glucagon-Like Peptide-1 Secretion through Gβγ-Mediated Pathway

Bupleurum falcatum L. has been used traditionally as a medicinal herb in Korean medicine. The hexane fraction of BF (HFBF), which was profiled with Direct Analysis in Real Time-Mass Spectrometry (DART-MS), activates the secretion of glucagon-like peptide-1 (GLP-1) in NCI-H716 cells significantly. We performed a microarray analysis and GLP-1 ELISA assay, as well as calcium imaging experiments with inhibitors, to investigate the mechanism of action of the HFBF. Through the microarray analysis, it was found that the ITPR2 gene that encodes the inositol 1,4,5-trisphosphate (IP3) receptor is up-regulated and the HFBF induces cell depolarization by inhibiting the voltage-gated channel expression in NCI-H716 cells. In addition, we found that the intracellular calcium in NCI-H716 cells, with Gallein, U73122, and 2APB as inhibitors, was decreased. These results suggest that the HFBF activates the GLP-1 secretion through the Gβγ pathways in the enteroendocrine L cells after treatment with the HFBF.

Anti-Inflammatory Effects of Ginsenoside Rg3 via NF-κB Pathway in A549 Cells and Human Asthmatic Lung Tissue

Objective. There is limited information of the anti-inflammatory effects of Rg3 on inflamed lung cells and tissues. Therefore, we confirmed the anti-inflammatory mechanism of ginsenoside Rg3 in inflamed human airway epithelial cells (A549) and tissues whether Rg3 regulates nuclear factor kappa B (NF-κB) activity. Methods. To induce the inflammation, IL-1β (10 ng/ml) was treated to A549 cells for 4 h. The effects of Rg3 on NF-κB activity and COX-2 expression were evaluated by western blotting analysis in both IL-1β-induced inflamed A549 cell and human asthmatic airway epithelial tissues. Using multiplex cytokines assay, the secretion levels of NF-κB-mediated cytokines/chemokines were measured. Result. Rg3 showed the significant inhibition of NF-κB activity thereby reduced COX-2 expression was determined in both IL-1β-induced inflamed A549 cell and human asthmatic airway epithelial tissues. In addition, among NF-κB-mediated cytokines, the secretion levels of IL-4, TNF-α, and eotaxin were significantly decreased by Rg3 in asthma tissues. Even though there was no significant difference, IL-6, IL-9, and IL-13 secretion showed a lower tendency compared to saline-treated human asthmatic airway epithelial tissues. Conclusion. The results from this study demonstrate the potential of Rg3 as an anti-inflammatory agent through regulating NF-κB activity and reducing the secretion of NF-κB-mediated cytokines/chemokines.