• Biomolecules & Therapeutics
• /
• 제28권2호
• /
• pp.163-171
• /
• 2020

Silibinin exhibits antidiabetic potential by preserving the mass and function of pancreatic β-cells through up-regulation of estrogen receptor-α (ERα) expression. However, the underlying protective mechanism of silibinin in pancreatic β-cells is still unclear. In the current study, we sought to determine whether ERα acts as the target of silibinin for the modulation of antioxidative response in pancreatic β-cells under high glucose and high fat conditions. Our in vivo study revealed that a 4-week oral administration of silibinin (100 mg/kg/day) decreased fasting blood glucose with a concurrent increase in levels of serum insulin in high-fat diet/streptozotocin-induced type 2 diabetic rats. Moreover, expression of ERα, NF-E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in pancreatic β-cells in pancreatic islets was increased by silibinin treatment. Accordingly, silibinin (10 μM) elevated viability, insulin biosynthesis, and insulin secretion of high glucose/palmitate-treated INS-1 cells accompanied by increased expression of ERα, Nrf2, and HO-1 as well as decreased reactive oxygen species production in vitro. Treatment using an ERα antagonist (MPP) in INS-1 cells or silencing ERα expression in INS-1 and NIT-1 cells with siRNA abolished the protective effects of silibinin. Our study suggests that silibinin activates the Nrf2-antioxidative pathways in pancreatic β-cells through regulation of ERα expression.

• Applied Microscopy
• /
• 제31권3호
• /
• pp.267-274
• /
• 2001

Streptozotocin(STZ)을 투여하여 고혈당을 유발시킨 생쥐의 이자섬에 생진양혈탕가미방이 미치는 영향을 규명하고자, 전방액 (0.4ml/day)을 21일간 투여하여 혈당 및 BUN의 변화와 인슐린 면역조직화학적 검색 및 전자 현미경을 이용한 $\beta$세포의 미세구조 변화를 관찰하였다. STZ을 투여한 대조군 이자섬의 면역조직화학적 검사 결과 insulin에 양성반응을 보이는 세포가 거의 관찰되지 않았으나, 생진양혈탕가미방을 투여한 실험군의 $\beta$세포들은 대조군에 비하여 강한 양성반응을 보였다. 전자현미경 관찰에서, 대조군 생쥐의 $\beta$세포는 핵의 핵막이 정상군에 비하여 뚜렷하지 않았으며 세포질소기관의 발달도 미약하였다. 세포질내에 함유되어 있는 분비과립의 수가 현저히 감소하였으며 전자밀도가 높은 중심부분의 크기도 정상군에 비하여 현저히 작았다. 실험군의 $\beta$세포에서는 insulin분비소포의 수는 정상군에 비하여 다소 적게 관찰되었으나 대조준에 비해서는 증가하였으며, 전자밀도가 높은 중심부분의 크기도 대조군에 비하여 다소 증가하였다. 혈당은 대조군($365.33{\pm}91.01$, mg/dl)에비하여 실험군($179.56{\pm}73.36$, mg/dl)에서 유의성있게 감소하였다. 위와 같은 결과로 보아 생진양혈탕가미방이 STZ로 유발된 당뇨 생쥐의 치료에 효능이 있음을 확인할 수 있었다.

• 대한의생명과학회지
• /
• 제18권3호
• /
• pp.193-200
• /
• 2012

We examined the effects of polyamines such as putrescine and cadaverine on the biosynthesis and secretion of insulin in the mouse pancreatic ${\beta}$-cell line, MIN-6. Basal insulin secretion (BIS) and glucose-stimulated insulin secretion (GSIS) from the MIN-6 cells were significantly increased by 20 min- or 24 h-treatment with micromolar concentrations of polyamines. To determine whether the enhancement was due to increase of insulin production by polyamines, we investigated the insulin mRNA and protein production. Both insulin mRNA and protein production were found to be not significantly affected by the polyamine treatment. Next, we examined the expression of several transcription factors (TFs) related to insulin synthesis and secretion in order to identify upstream events responsible for the promotion of insulin secretion of MIN6 cells by polyamines. Of the 6 TFs tested, MafA was induced by treatment of polyamines. MafA mRNA and protein expressions increased with treatment of polyamines. Overall results suggest that cadaverine and putrescine promote the insulin secretion process rather than the insulin biosynthesis from MIN6 cells. Also MafA may be involved in the enhanced insulin secretion process. Further studies are needed to elucidate the underlying mechanisms for promotion of insulin secretion by polyamines.

• 동의생리병리학회지
• /
• 제22권2호
• /
• pp.422-426
• /
• 2008

In this study, the preventive effects of Radix Trichosanthis extracts (RTE) against cytokine-induced ${\beta}-cell$ death were assessed. Cytokines generated by immune cells infiltrating pancreatic islets are crucial mediators of ${\beta}-cell$ destruction in insulin-dependent diabetes mellitus. The treatment of RIN cells with $interleukin-1{\beta}$ ($IL-1{\beta}$) and $interferon-{\gamma}$ ($IFN-{\gamma}$) resulted in a reduction of cell viability. RTE protected $IL-1{\beta}$ and $IFN-{\gamma}$-mediated viability reduction in a concentration-dependent manner. Incubation with RTE also induced a significant suppression of $IL-1{\beta}$ and $IFN-{\gamma}$-induced inducible nitric oxide synthase (iNOS) protein expression. The molecular mechanism by which RTE inhibited iNOS protein expression appeared to involve the inhibition of $NF{-\kappa}B$ activation. The $IL-1{\beta}$ and $IFN-{\gamma}$-stimulated RIN cells showed increases in $NF{-\kappa}B$ binding activityand $I{\kappa}B{\alpha}$ degradation in cytosol compared to unstimulated cells. However, pretreatment with RTE inhibited cytokines-induced $I{\kappa}B{\alpha}$ degradation and $NF{-\kappa}B$ activation in RINm5F cells. Furthermore, the protective effects of RTE were verified via protection of impairment in glucose-stimulated insulin secretions in $IL-1{\beta}$ and $IFN-{\gamma}$-treated islets.

• Food Science and Biotechnology
• /
• 제17권5호
• /
• pp.947-952
• /
• 2008

The unripe fruit of Momordica charantia (MC) has been shown to possess antidiabetic activity. However, the mechanism of its antidiabetic action has not been fully understood. In this study, the effects of the aqueous ethanolic extract of MC (AEE-MC) were evaluated on the apoptosis in pancreatic $\beta$-cells treated with a combination of the cytokines, interleukin (IL)-$1{\beta}$, tumor necrosis factor (TNF)-$\alpha$, and interferon (IFN)-$\gamma$. In MIN6N8 cells, the inhibitory effect of AEE-MC was significantly observed at 2 to 50 ${\mu}g/mL$: a 26.2 to 55.6% decrease of cytoplasmic DNA fragments quantified by an immunoassay. The molecular mechanisms, by which AEE-MC inhibited $\beta$-cell apoptosis, appeared to involve the inhibition on the expression of p21, Bax, and Bad, the up-regulation of Bcl-2 and Bcl-$X_L$, and the inhibition on the cleavage of caspase-9, -7, and -3 and poly (ADP-ribose) polymerase. This study suggests that MC may inhibit cytokine-induced apoptosis in $\beta$-cells and, thus, may contribute via this action to the antidiabetic influence in diabetes.

• Journal of Ginseng Research
• /
• 제47권4호
• /
• pp.572-582
• /
• 2023

Background: Free fatty acid-induced lipotoxicity is considered to play an important role in pancreatic β-cell dysfunction. The effect of ginsenosides on palmitic acid-induced pancreatic beta-cells cell death and failure of glucose-stimulated secretion of insulin (GSIS) was evaluated in this study. Methods: Enzyme-linked immunosorbent assay kit for a rat insulin was used to quantify glucose-stimulated insulin secretion. Protein expression was examined by western blotting analysis. Nuclear condensation was measured by staining with Hoechst 33342 stain. Apoptotic cell death was assessed by staining with Annexin V. Oil Red O staining was used to measure lipid accumulation. Results: We screened ginsenosides to prevent palmitic acid-induced cell death and impairment of GSIS in INS-1 pancreatic β-cells and identified protopanaxadiol (PPD) as a potential therapeutic agent. The protection effect of PPD was likely due to a reduction in apoptosis and lipid accumulation. PPD attenuated the palmitic acid-induced increase in the levels of B-cell lymphoma-2-associated X/B-cell lymphoma 2, poly (ADP-ribose) polymerase and cleaved caspase-3. Moreover, PPD prevented palmitic acid-induced impairment of insulin secretion, which was accompanied by an increase in the activation of phosphatidylinositol 3-kinase, peroxisome proliferator-activated receptor γ, insulin receptor substrate-2, serine-threonine kinase, and pancreatic and duodenal homeobox-1. Conclusion: Our results suggest that the protective effect of PPD on lipotoxicity and lipid accumulation induced by palmitic acid in pancreatic β-cells.

• Journal of Cancer Prevention
• /
• 제22권1호
• /
• pp.1-5
• /
• 2017

Pancreatic cancer is a highly aggressive malignant tumor of the digestive system and radical resection, which is available to very few patients, might be the only possibility for cure. Since therapeutic choices are limited at the advanced stage, prevention is more important for reducing incidence in high-risk individuals with family history of pancreatic cancer. Epidemiological studies have shown that a high consumption of fish oil or ${\omega}3-polyunsaturated$ fatty acids reduces the risk of pancreatic cancers. Dietary fish oil supplementation has shown to suppress pancreatic cancer development in animal models. Previous experimental studies revealed that several hallmarks of cancer involved in the pathogenesis of pancreatic cancer, such as the resistance to apoptosis, hyper-proliferation with abnormal $Wnt/{\beta}-catenin$ signaling, expression of pro-angiogenic growth factors, and invasion. Docosahexaenoic acid (DHA) is a ${\omega}3-polyunsaturated$ fatty acid and rich in cold oceanic fish oil. DHA shows anti-cancer activity by inducing oxidative stress and apoptosis, inhibiting $Wnt/{\beta}-catenin$ signaling, and decreasing extracellular matrix degradation and expression of pro-angiogenic factors in pancreatic cancer cells. This review will summarize anti-cancer mechanism of DHA in pancreatic carcinogenesis based on the recent studies.

• 동의생리병리학회지
• /
• 제22권4호
• /
• pp.791-795
• /
• 2008

In the present study, Cordyceps sinensis extract (CSE) was evaluated to determine if it could protect pancreatic ${\beta}$ cells against cytokine-induced cytotoxicity of RINm5F cells. Treatment of cells with cytokines resulted in a decrease of viability, which was caused by increase of nitric oxide (NO) production. CSE protected cytokine-mediated viability reduction in a concentration-dependent manner. Incubation with CSE also induced a significant suppression of cytokine-induced inducible nitric oxide synthase (iNOS) protein and NO production. The molecular mechanism by which CSE inhibited iNOS protein expression appeared to involve the inhibition of $NF-{\kappa}B$ activation. The cytokine-stimulated RIN cells showed increases in $NF-{\kappa}B$ binding activity compared to unstimulated cells. However, pretreatment with CSE inhibited cytokines-induced $NF-{\kappa}B$ activation in RINm5F cells.

• The Korean Journal of Physiology and Pharmacology
• /
• 제17권4호
• /
• pp.315-320
• /
• 2013

Here, we show that radicicol, a fungal antibiotic, resulted in marked inhibition of inducible nitric oxide synthase (iNOS) transcription by the pancreatic beta cell line MIN6N8a in response to cytokine mixture (CM: TNF-${\alpha}$, IFN-${\gamma}$, and IL-$1{\beta}$). Treatment of MIN6N8a cells with radicicol inhibited CM-stimulated activation of NF-${\kappa}B$/Rel, which plays a critical role in iNOS transcription, in a dose-related manner. Nitrite production in the presence of PD98059, a specific inhibitor of the extracellular signal-regulated protein kinase-1 and 2 (ERK1/2) pathway, was dramatically diminished, suggesting that the ERK1/2 pathway is involved in CM-induced iNOS expression. In contrast, SB203580, a specific inhibitor of p38, had no effect on nitrite generation. Collectively, this series of experiments indicates that radicicol inhibits iNOS gene expression by blocking ERK1/2 signaling. Due to the critical role that NO release plays in mediating destruction of pancreatic beta cells, the inhibitory effects of radicicol on iNOS expression suggest that radicicol may represent a useful anti-diabetic activity.

• 한국발생생물학회지:발생과생식
• /
• 제11권2호
• /
• pp.67-77
• /
• 2007

최근 제 1형 당뇨병을 치료하기 위하여 인슐린-분비성 세포를 이식하는 세포대체요법이 새로운 치료법으로서 주목받고 있다. 그럼에도 불구하고 췌장세포 이식술은 이식원의 절대적인 부족으로 인해 광범위한 시행이 이루어지지 못하고 있는 실정이다. 무한증식과 전분화능을 보유하는 배아줄기세포는 이식할 $\beta$-세포의 부족을 해결할 수 있는 잠재적 세포공급원이 될 수 있을 것으로 기대된다. 본 종설에서는 인간배아줄기세포로부터 췌장 $\beta$-세포로의 유도분화방법에 관한 최근 동향을 살펴보고, 당뇨병 치료에 세포 이식술을 적용함에 있어 고려해야할 문제점 및 극복방안들을 소개하고자 한다.