Search for nutrients or drugs to improve metabolism by use of regulatory mechanism of ghrelin receptor gene transcription

利用ghrelin受体基因转录调控机制寻找改善新陈代谢的营养物质或药物

• 批准号: 14571070
• 负责人: KAJI Hidesuke
• 金额: $ 1.86万
• 依托单位: College of nursing Art & Science, Hyogo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14571070/
• 关键词: Ghrelin; Receptor; Gene transcription; HepG2 cell; Oleylethanoamide; Polyunsaturated fatty acid; Insulin sensitivity; Adiponectin; HeP G2細胞; 糖尿病; 肥満症; GH secretagogue受容体(GHS-R); HepG2細胞; 転写調節; 遺伝子; エンコサペンタエン酸EPA

A though patients with diabetes or obesity require severe restriction of calorie intake, it is usually hard to continue. Ghrelin, a ligand for growth hormone secretagogue receptor (GHS-R), was isolated from stomach and reported to play roles in stimulation of appetite as well as GH secretion. In addition, we have reported the role of ghrelin against insulin action in cultured hepatocytes In this study, we searched which nutrients or drugs might affect GHS-R gene transcription by luciferase assay system. The transcriptional activity (GHS-R/Luc) was located between -608 and -534p of 5'-flanking region of GHS-R gene, where AP_2 or bHLH was expected to bind. Gel shift assay demonstrated that fluorecent labeled DNA of this region specifically bound to nuclear proteins extracted from HepG_2 cells. Eicosa-pentaenoic acid (EPA) or troglitazone slightly inhibited GHS-R/Luc activity. These results suggest that EPA or troglitazone enhance insulin sensitivity, at least in part, by down-regulation of GHS-R. On the other hand, anorexic lipid, oleylethanolamide, caused a slight increase in GHS-R/Luc activity. We have experienced patients who had taken a certain diet tea and subsequently became diabetic. This diet tea inhibited glucose-induced insulin secretion from cultured pancreatic cells RIN-5F. However, this tea did not change GHS-R/Luc activity. Vitamin C,E, insulin, ghrelin, and leptin did not change GHS-R/Luc activity. As EPA caused down-regulation of GHS-R, we challenged polyunsaturated fatty acid (PUFA)-rich diet in young volunteer. The PUFA-rich diet caused an increase in HOMA-IR with a precedent elevation of plasma adiponectin levels. In conclusion, measurement of transcriptional activity of genes involved in metabolism is a useful way to search nutrients or drugs for prevention of diabetes or obesity.

尽管糖尿病或肥胖患者需要严格限制热量摄入，但通常很难持续。 Ghrelin 是生长激素促分泌素受体 (GHS-R) 的配体，从胃中分离出来，据报道在刺激食欲和 GH 分泌中发挥作用。此外，我们还报道了ghrelin在培养的肝细胞中对抗胰岛素作用的作用。在本研究中，我们通过荧光素酶检测系统寻找哪些营养素或药物可能影响GHS-R基因转录。转录活性(GHS-R/Luc)位于GHS-R基因5'-侧翼区域的-608和-534p之间，AP_2或bHLH预计在此处结合。凝胶位移分析表明，该区域的荧光标记 DNA 与从 HepG_2 细胞中提取的核蛋白特异性结合。二十碳五烯酸 (EPA) 或曲格列酮轻微抑制 GHS-R/Luc 活性。这些结果表明，EPA 或曲格列酮至少部分通过下调 GHS-R 来增强胰岛素敏感性。另一方面，厌食脂质油乙醇酰胺导致 GHS-R/Luc 活性略有增加。我们遇到过服用某种减肥茶后患上糖尿病的患者。这种减肥茶可抑制培养的胰腺细胞 RIN-5F 中葡萄糖诱导的胰岛素分泌。然而，这种茶并没有改变 GHS-R/Luc 活性。维生素 C、E、胰岛素、生长素释放肽和瘦素不会改变 GHS-R/Luc 活性。由于 EPA 导致 GHS-R 下调，我们对年轻志愿者的富含多不饱和脂肪酸 (PUFA) 的饮食提出了挑战。富含 PUFA 的饮食导致 HOMA-IR 增加，血浆脂联素水平先行升高。总之，测量参与代谢的基因的转录活性是寻找预防糖尿病或肥胖的营养素或药物的有用方法。

项目成果

Sakurai T, iida K, Takahashi Y, Kaji H, Takakuwa S, Sumita R, et al.: "A novel heterozygous T51I mutation of growth hormone receptor is not associated with short stature"Growth Hormone & IGF Research. 12. 411-417 (2002)

Sakurai T、iida K、Takahashi Y、Kaji H、Takakuwa S、Sumita R 等人：“生长激素受体的新型杂合 T51I 突变与身材矮小无关”生长激素

Murata M, Okimura Y, Iida K, Matsumoto M, Kaji H et al.: "Ghrelin modulates the downstream molecules of insulin signaling in hepatoma cells"The Journal of Biological Chemistry. 277,7. 5667-5674 (2002)

Murata M、Okimura Y、Iida K、Matsumoto M、Kaji H 等人：“Ghrelin 调节肝癌细胞中胰岛素信号传导的下游分子”《生物化学杂志》。

Kishimoto M, Okimura Y, Nakata H, Kaji H, et al.: "The R271W mutant form of Pit-1 does not act as a dominant inhibitor of Pit-1 action to activate the promoters of GH and prolactin genes."European Journal of Endocrinology. 148. 619-625 (2003)

Kishimoto M、Okimura Y、Nakata H、Kaji H 等人：“Pit-1 的 R271W 突变体形式不能作为 Pit-1 作用的显性抑制剂来激活 GH 和催乳素基因的启动子。”《欧洲杂志》

Iida K, Okimura Y, Takahashi K, Kaji H et al.: "A variety of phenotype with R161Q germline mutation of the von Hippel-Lindau tumor suppressor gene in Japanese kindred."International Journal of Molecular Medicine. 13・3. 401-404 (2004)

Iida K、Okimura Y、Takahashi K、Kaji H 等：“日本亲属中 von Hippel-Lindau 肿瘤抑制基因的 R161Q 种系突变的多种表型。”国际分子医学杂志 13・3。 404（2004）

Kaji H, Sakurai T, Iguchi G, Murata M, Yoshioka S et al.: "Adult growth hormone deficiency in Japan Results of investigation by questionnaire"Endocrine Journal. 49. 597-604 (2002)

Kaji H、Sakurai T、Iguchi G、Murata M、Yoshioka S 等：“日本成人生长激素缺乏症问卷调查结果”内分泌杂志。