So Hee Nam

Differential regulation of the biosynthesis of glucose transporters by the PI3-K and MAPK pathways of insulin signaling by treatment with novel compounds from Liriope platyphylla

The insulin signaling pathway, involving protein kinase B (PKB) and mitogen-activated protein kinase (MAPK), mediates the biological response to insulin and several growth factors and cytokines. To investigate the correlation between glucose transporter (Glut) biosynthesis and the insulin signaling pathway activated by novel compounds of Liriope platyphylla (LP9M80-H), alterations in Glut and key protein expression in the insulin signaling pathway were analyzed in the liver and brain of ICR mice treated with LP9M80-H. An in vitro assay showed that the highest level of insulin concentration was observed in the LP9M80-H-treated group, followed by the LP-H, LP-M, LP-E, and LP9M80-C-treated groups. Therefore, LP9M80-H was selected for use in studying the detailed mechanism of the insulin signaling pathway in animal systems. In an in vivo experiment, LP9M80-H induced a significant increase in glucose levels and a decrease of insulin concentration in the blood of mice, while their body weight remained constant over 5 days. The expression level of Glut-3 was down-regulated in the liver, or maintained at the same level in the brain of LP9MH80-H-treated mice. These changes corresponded to the phosphorylation of the p38 protein rather than to ERK and JNK in the MAPK signaling pathway. In addition, the expression level of Glut-1 increased significantly after LP9MH80-H treatment of both insulin target tissues in mice. Western blot analysis showed that Akt in the PI3-K pathway mainly participated in Glut-1 biosynthesis. Thus, these results suggest the possibility that the LP9M80-H-induced regulation of Glut-1 and Glut-3 biosynthesis may be mediated by the Akt and p38 MAPK signaling of the insulin signaling pathway in the liver and brain of mice.

Effects of Steaming Time and Frequency for Manufactured Red Liriope platyphylla on the Insulin Secretion Ability and Insulin Receptor Signaling Pathway.

In oriental medicine, Liriope platyphylla (LP) has long been regarded as a curative herb useful for the treatment of diabetes, asthma, and neurodegenerative disorders. The principal objective of this study was to assess the effects of steaming time and frequency for manufactured Red LP (RLP) on insulin secretion ability and insulin receptor signaling pathway. To achieve our goal, several types of LPs manufactured under different conditions were applied to INS cells and streptozotocin (STZ)-induced diabetic ICR mice, after which alterations in insulin concentrations were detected in the culture supernatants and sera. The optimal concentration for the investigation of insulin secretion ability was found to be 50 ug/mL of LP. At this concentration, maximum insulin secretion was observed in the INS cells treated with LP extract steamed for 3 h (3-SLP) with two repeated steps (3 h steaming and 24 h air-dried) carried out 9 times (9-SALP); no significant changes in viability were detected in any of the treated cells. Additionally, the expression and phosphorylation levels of most components in the insulin receptor signaling pathway were increased significantly in the majority of cells treated with steaming-processed LP as compared to the cells treated with LP prepared without steaming. With regard to glucose transporter (GLUT) expression, alterations of steaming time induced similar responses on the expression levels of GLUT-2 and GLUT-3. However, differences in steaming frequency were also shown to induce dose-dependent responses in the expression level of GLUT-2 only; no significant differences in GLUT-3 expression were detected under these conditions. Furthermore, these responses observed in vitro were similarly detected in STZ-induced diabetic mice. 24-SLP and 9-SALP treatment applied for 14 days induced the down-regulation of glucose concentration and upregulation of insulin concentration. Therefore, these results indicated that the steaming processed LP may contribute to the relief of diabetes symptoms and should be regarded as an excellent candidate for a diabetes treatment.

Differential effects of the steaming time and frequency for manufactured red Liriope platyphylla on nerve growth factor secretion ability, nerve growth factor receptor signaling pathway and regulation of calcium concentration

The herb Liriope platyphylla (LP) has been considered to have curative properties for diabetes, asthma and neurodegenerative disorders. To examine the effects of steaming time and frequency of manufactured red LP (RLP) on the nerve growth factor (NGF) secretion ability and NGF receptor signaling pathway, the NGF concentration, cell differentiation, NGF signaling pathway and calcium concentration were analyzed in neuronal cells treated with several types of LPs manufactured under different conditions. The maximum NGF secretion was observed in B35 cells treated with 50 µg/ml LP extract steamed for 9 h (9-SLP) and with two repeated steps (3 h steaming and 24 h air-dried) carried out 7 times (7-SALP). No significant changes in viability were detected in any of the cells treated with the various LPs, with the exception of 0-SLP and 0-SALP. In addition, PC12 cell differentiation was induced by treatment with the NGF-containing conditional medium (CM) collected from the RLP-treated cells. The levels of TrkA and extracellular signal-regulated kinase (ERK) phosphorylation in the high affinity NGF receptor signaling pathway were significantly higher in the cells treated with 3-SLP or 1-SALP/3-SALP CM compared with those treated with the vehicle CM. In the low affinity NGF receptor pathway, the expression levels of most components were higher in the 9-, 15- and 24-SALP CM-treated cells compared with the vehicle CM-treated cells. However, this level was significantly altered in cells treated with 3-SALP CM. Furthermore, an examination of the RLP function on calcium regulation revealed that only the LP- or RLP-treated cells exhibited changes in intracellular and extracellular calcium levels. RLP induced a significant decrease in the intracellular calcium levels and an increase in the extracellular calcium levels. These results suggest the possibility that steaming-processed LP may aid in the relief of neurodegenerative diseases through the NGF secretion ability and NGF signaling pathway.

LP9M80-H Isolated from Liriope platyphylla Could Help Alleviate Diabetic Symptoms via the Regulation of Glucose and Lipid Concentration

It was reported that the novel compounds (LP9M80-H) of Liriope platyphylla regulate glucose transporter (Glut) biosynthesis by activating the insulin-signaling pathway in the liver and brain of ICR mice. To investigate the therapeutic effects of LP9M80-H on the pathology of diabetes and obesity, alterations of key factors related to symptoms were analyzed in the Otsuka Long Evans Tokushima Fatty (OLETF) rats treated with LP9M80-H for 2 weeks. The abdominal fat masses in the LP9M80-H-treated group were lower than the vehicle-treated group, although there was no difference in body weight between the two groups. Additionally, when compared to the vehicle-treated group, LP9M80-H treatment induced a significant decrease in glucose levels and an increase in the insulin concentration in the blood of OLETF rats. A high level of insulin protein was also detected in pancreatic β cells of LP9M80-H-treated OLETF rats. A significant reduction in the concentration of lipids and adiponectin was detected only in LP9M80-H-treated OLETF rats. Furthermore, the expression of insulin receptor β and the insulin receptor substrate (IRS) was dramatically decreased in LP9M80-H-treated OLETF rats compared to the vehicle-treated group. Of the glucose transporters located downstream of the insulin-signaling pathway, glucose transporters (Glut) -2 and -3 were significantly decreased in LP9M80-H-treated OLETF rats, while the level of Glut-4 was maintained under all conditions. Therefore, these results suggest that LP9M80-H may contribute to relieving symptoms of diabetes and obesity through glucose homeostasis and regulation of lipid concentration.

The Extracts from Liriope platyphylla Significantly Stimulated Insulin Secretion in the HIT-T15 Pancreatic β-Cell Line

맥문동(Liriope platyphylla)은 한국과 중국에서 전통적으로 당뇨, 비만, 뇌신경질환, 천식 등의 치료를 위해 사용 해온 치료제이다. 최근에 이들 맥문동으로부터 새로운 치료제를 개발하려는 노력이 활발히 진행 중이지만 아직도 유력한 치료후보제는 확보되지 않았다. 따라서 본 연구에서는 맥문동의 새로운 추출물을 이용하여 당뇨치료 제로서의 가능성을 평가하기 위하여 새로운 방법으로 10가지 후보물질을 추출하고 이들의 독성과 효능을 평가하였다. 그 결과 10가지 추출물 중에서 LP9M80-H가 인슐린 분비를 가장 많이 촉진하였고 다음으로는 LP-H, LP-M, LP-E과 LP9M80-C 등의 순서로 촉진을 하였으나 나머지는 인슐린 분비를 촉지하지 못하였다. 그러나 이들 물질은 인슐린 분비를 촉진하는 농도에서 강한 세포 독성을 나타내었다. 따라서 이들 물질 중에서 가장 효능이 좋은 LP9M80-H의 치료용 최적농도를 설정하였으며, 대략 100-25 ug/ml가 최적농도로 결정되었다. 이러한 결과는 맥문동 추출물 중에서 LP9M80-H가 췌장

Peroxiredoxin I regulates the component expression of γ-secretase complex causing the Alzheimer’s disease

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Overexpression of Insulin Degrading Enzyme could Greatly Contribute to Insulin Down-regulation Induced by Short-Term Swimming Exercise.

-세포의 인슐린 분비능을 유도하는 새로운 당뇨치료 후보물질로서 향후에 사용될 가능성을 시사하고 있다. 【Liriope platyphylla has traditionally been used in Korea and China as a therapeutic drug for the treatment of coughing, sputum, neurodegenerative disorders, obesity, and diabetes. In an effort to assess the functions of a novel extract from Liriope platyphylla in diabetes therapy, the insulin secretion abilities of 10 extracts were screened via measurements of insulin concentration in the culture supernatant using an Insulin ELISA kit. The results of this assay showed the highest levels of insulin in the LP9M80-H treated group, followed by the LP-H, LP-M, LP-E and LP9M80-C treated groups, whereas other extracts did not induce insulin secretion in the HIT-T15 cells. However, the extracts capable of stimulating insulin secretion simultaneously evidenced high apoptotic activity as compared with other extracts. Therefore, one of these extracts, LP9M80-H, was initially selected as the optimal candidate for a therapeutic drug and its optimal concentration was determined. The results of the ELISA and MTT assay demonstrated that a concentration of approximately 100-125 ug/ml of LP9M80-H was optimal with regards to cell viability and insulin secretion in the HIT-T15 cells. These results suggest that LP9M80-H could be considered as an excellent candidate for a diabetes-therapeutic drug that could induce insulin secretion in pancreatic

Pen-2 overexpression induces Aβ-42 production, memory defect, motor activity enhancement and feeding behavior dysfunction in NSE/Pen-2 transgenic mice

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Construction and In vitro Study of a Prx 6/Luc Vector System for Screening Antioxidant Compounds in the Transgenic Mice

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Aβ-42 deposition significantly increases the insolubility of synaptophysin in the brains of hAPPsw/hPS2m double transgenic mice

Peroxiredoxin I (Prx I) is a member of the peroxiredoxins (Prxs) family, which are antioxidant enzymes that regulate various cellular process via intracellular oxidative signal pathways. In order to investigate the correlation between Prx I and the γ-secretase complex, which causes Alzheimers disease (AD), the expression level of Prx I was firstly evaluated in an animal model for AD. NSE/hPen-2 transgenic (Tg) mice, which were used as animal model in this study, showed a high level of Pen-2 expression and accumulation of Aβ-42 peptides in the hippocampus of brain. The expression level of Prx I was significantly higher on the mRNA and protein level in the brain of this model, while not change in Prx VI expression was observed. Furthermore, to verify the effect of Prx I on the γ-secretase components in vitro, the expression level of these components was analyzed in the Prx I transfectants. Of the components of the γ-secretase complex, the expression of PS-2 and Pen-2 was lower in the transfectants overexpressing Prx I compared to the vector transfectants. However, the expression of APP, NCT and APH-1 did not change in Prx I transfectants. Therefore, these results suggested that the expression of Prx I may be induced by the accumulation of Aβ-42 peptides and the overexpression of Prx I in neuroblastoma cells may regulate the expression of γ-secretase components.