• 한국식품저장유통학회지
• /
• 제24권7호
• /
• pp.1007-1016
• /
• 2017

다슬기는 예로부터 간염, 간경화, 지방간 등의 치료 및 개선에 이용되어 왔으며, 특히 소변불통, 소갈증(당뇨) 등의 약용으로 이용되어 왔다. 본 연구에서는 이러한 다슬기를 대상으로 항당뇨에 대한 효능을 과학적으로 검증하고 그 기작을 규명하고자 하였다. 먼저 다슬기의 생물학적 기능성을 높이기 위해 효소 가수분해를 실시하였으며, protamex에 의한 가수분해도는 10시간 후 약 43% 수준을 나타내었다. PTP1B는 인슐린 신호전달기전에서 IRS-1의 인산화를 방해하여 인슐린 민감성을 저해시키는 효소이다. protamex를 이용한 다슬기 가수분해물(MPH)의 PTP1B에 대한 저해활성은 $15.42{\pm}1.1{\mu}g/mL$의 $IC_{50}$ 값을 나타내어 양성대조군 ursolic acid의 $16.7{\mu}g/mL$ 보다 높은 저해활성을 보이면서 강한 항당뇨 활성 소재로서의 가능성을 보였다. 이에 따라 유리지방산을 이용하여 C2C12 myoblast에서 인슐린 저항성을 유도하고, MPH에 의한 포도당 흡수 정도를 확인하였다. 그 결과, 1 mM PA 처리에 의해 약 32% 수준으로 떨어진 포도당 흡수율은 MPH 처리에 의해 약 199% 수준으로 증가하였다. 또한 장기간 고농도의 포도당(30 mM)에 의해 유도된 당독성 조건에서 MPH는 췌장의 베타세포 INS-1 세포의 생존율을 증가시키고, 대조군에 비해 약 160% 인슐린 mRNA 발현량을 증가시켰다. 이러한 결과에서 MPH는 PTP1B 활성을 저해함으로써 인슐린 신호전달 기작을 활성화하고, 인슐린저항성 환경에서 포도당 흡수를 증진시켜 인슐린저항성을 개선하며, 나아가 고농도 포도당에 의해 유도되는 당독성환경에서 췌장 베타세포를 보호하고 인슐린 mRNA발현량을 정상화할 수 있다는 것을 확인할 수 있었다.

• 대한한의학회지
• /
• 제31권4호
• /
• pp.79-100
• /
• 2010

Objective: Production of ROS from glucose toxicity results in injury of pancreatic $\beta$-cells in diabetes models. This study was undertaken to examine the influence of Lespedeza Cuneata extract (LCE) on cytoprotective effects on glucose toxicity, insulin secretion and gene expression in RIN-m5F cells. Methods: First, we measured LCE's antioxidant activity by DPPH free radical-scavenging activity and SOD activity. After the various concentrations of LCE were added to the RIN-m5F cells, we measured cell viability with glucose stimulation by MTT assay and glucose-stimulated insulin secretion. We analyzed gene expression with Agilent whole mouse genome 44K oligo DNA microarray and searched for related pathways in KEGG (Kyoto Encyclopedia of Genes and Genomes). Lastly we measured INS-1, INS-2, INS-R, IRS-1, IRS-2, IRS-3, GLP-1R, and GLP-2R mRNA expression by real time RT-PCR. Results: Free radical-scavenging activity, SOD activity and insulin secretion increased dependent on LCE concentration, but LCE did not show considerable cytoprotective effect on RIN-m5F cells. More than twice expressed gene was 6362 in Oligo DNA chip. In KEGG, the most related pathway was the metabolic pathway. In the insulin signaling pathway, up expressed genes were Irs1, Mapk8, Akt1, and Lipe and down expressed genes were Rhoq, Fbp2, Prkar2b, Gck, and Prkag1. In real time RT-PCR, IRS-2, and IRS-3 expression increased significantly compared to the control group on LCE $12{\mu}g/m{\ell}$ concentration and GCK expression decreased significantly compared to the control group. Conclusions: These results show that LCE encourages insulin secretion and insulin metabolism by complicated gene mechanisms. Further mechanism study and clinical study seem to be necessary about Lespedeza Cuneata.

• BMB Reports
• /
• 제43권2호
• /
• pp.146-149
• /
• 2010

Exendin-4 (Ex-4), a peptide secreted from the salivary glands of the Gila monster lizard, can increase pancreatic $\beta$-cell growth and insulin secretion by activating glucagon-like peptide-1 receptor. In this study, we expressed a fusion protein consisting of exendin-4 and the human immunoglobulin heavy chain (Ex-4/IgG-Fc) in E. coli and explored its potential therapeutic use for the treatment of insulin-resistant type 2 diabetes. Here, we show that the Ex-4/IgG-Fc fusion protein induces expression of insulin receptor substrate-2 in rat insulinoma INS-1 cells. Our findings therefore suggest that Ex-4/IgG-Fc overexpressed in E. coli could be used as a potential, long-acting glucagon-like peptide-1 mimetic.

• Genomics & Informatics
• /
• 제12권4호
• /
• pp.240-246
• /
• 2014

Mutation in HNF1B, the hepatocyte nuclear factor-$1{\beta}$ (HNF-$1{\beta}$) gene, results in maturity-onset diabetes of the young (MODY) 5, which is characterized by gradual impairment of insulin secretion. However, the functional role of HNF-$1{\beta}$ in insulin secretion and glucose metabolism is not fully understood. We identified a family with early-onset diabetes that fulfilled the criteria of MODY. Sanger sequencing revealed that a heterozygous P159L (CCT to CTT in codon 159 in the DNA-binding domain) mutation in HNF1B was segregated according to the affected status. To investigate the functional consequences of this HNF1B mutation, we generated a P159L HNF1B construct. The wild-type and mutant HNF1B constructs were transfected into COS-7 cells in the presence of the promoter sequence of human glucose transporter type 2 (GLUT2). The luciferase reporter assay revealed that P159L HNF1B had decreased transcriptional activity compared to wild-type (p < 0.05). Electrophoretic mobility shift assay showed reduced DNA binding activity of P159L HNF1B. In the MIN6 pancreatic ${\beta}$-cell line, overexpression of the P159L mutant was significantly associated with decreased mRNA levels of GLUT2 compared to wild-type (p < 0.05). However, INS expression was not different between the wild-type and mutant HNF1B constructs. These findings suggests that the impaired insulin secretion in this family with the P159L HNF1B mutation may be related to altered GLUT2 expression in ${\beta}$-cells rather than decreased insulin gene expression. In conclusion, we have identified a Korean family with an HNF1B mutation and characterized its effect on the pathogenesis of diabetes.