Protein Chip-based GLP-1 Receptor Assay System

박찬원,강인철 한국바이오칩학회 2014 BioChip Journal Vol.8 No.3

We investigated GLP-1 Receptor (GLP-1R) assay system on the basis of receptor-ligand interactionusing ProteoChip. GLP-1R was immobilized onthe surface of the ProteoChip and then GLP-1 peptidelabeled with a Cy5-fluorescent dye was interacted withthe GLP-1R array on the chip in a dose-dependentmanner. Exendin-4 was tested for targeting GLP-1Rto demonstrate the chip-based GLP-1R assay system. Chemical compound 6 and 45 were screened as novelagonists of GLP-1R using the GLP-1R assay system. The compound significantly inhibited GLP-1 bindingto GLP-1R in a dose-dependent manner. The proteinchip-based GLP-1R assay system will serve as a usefultool for screening of novel GLP-1R agonists.

Central administration of GLP-1 and GIP decreases feeding in mice

NamKoong, C.,Kim, M.S.,Jang, B.T.,Lee, Y.H.,Cho, Y.M.,Choi, H.J. Academic Press 2017 Biochemical and biophysical research communication Vol. No.

Glucagon-like peptide-1 amide (GLP-1) and gastric inhibitory polypeptide (GIP) are incretin hormones regulating energy metabolism. GLP-1 and GIP combination is suggested as a promising therapeutic strategy for treatment of obesity and diabetes. However, the neuronal mechanisms are not yet investigated. In the present study, we investigated the role of central GLP-1 and GIP in regulation of body weight homeostasis. The effect of GLP-1 with GIP on food intake, body weight, locomotor activity were determined following intracerebroventricular (ICV) administration of GLP-1 and/or GIP in mice. ICV administration of low dose GLP-1 (0.3 nmol) and GIP (1 and 3 nmol) did not change food intake. However, ICV administration of higher doses GLP-1 (1 and 3 nmol) and GIP (6 nmol) significantly decreased food intake and body weight. To investigate the synergic effect of ICV GLP-1 and GIP, subeffective dose GLP-1 (0.3 nmol) and subeffective dose GIP (1 nmol) were chosen for further co-administration study. ICV co-administration of GLP-1 and GIP significantly decreased food intake, body weight and drinking. ICV co-administration of GLP-1 and GIP significantly increased neuronal activation and pro-opiomelanocortin (POMC) expression in hypothalamic arcuate nucleus. The neuronal activation and POMC expression were observed in two distinct neuronal populations. These results provide neuronal mechanisms supporting the development of GLP-1 and GIP combination therapeutics for treatment of obesity and diabetes.

MOLECULAR EVOLUTION OF GPCRS: GLP1/GLP1 receptors

Hwang, Jong-Ik,Yun, Seongsik,Moon, Mi Jin,Park, Cho Rong,Seong, Jae Young Journal of Endocrinology (Ltd. by Guarantee) 2014 Journal of molecular endocrinology Vol.52 No.3

<P>Glucagon-like peptide 1 (GLP1) is an intestinal incretin that regulates glucose homeostasis through stimulation of insulin secretion from pancreatic β-cells and inhibits appetite by acting on the brain. Thus, it is a promising therapeutic agent for the treatment of type 2 diabetes mellitus and obesity. Studies using synteny and reconstructed ancestral chromosomes suggest that families for GLP1 and its receptor (GLP1R) have emerged through two rounds (2R) of whole genome duplication and local gene duplications before and after 2R. Exon duplications have also contributed to the expansion of the peptide family members. Specific changes in the amino acid sequence following exon/gene/genome duplications have established distinct yet related peptide and receptor families. These specific changes also confer selective interactions between GLP1 and GLP1R. In this review, we present a possible macro (genome level)- and micro (gene/exon level)-evolution mechanisms of GLP1 and GLP1R, which allows them to acquire selective interactions between this ligand–receptor pair. This information may provide critical insight for the development of potent therapeutic agents targeting GLP1R.</P>

$Tyr^1$ and $Ile^7$ of Glucose-Dependent Insulinotropic Polypeptide (GIP) Confer Differential Ligand Selectivity toward GIP and Glucagon-like Peptide-1 Receptors

Moon, Mi-Jin,Kim, Hee-Young,Kim, Sin-Gon,Park, Ju-Ri,Choi, Dong-Seop,Hwang, Jong-Ik,Seong, Jae-Young Korean Society for Molecular and Cellular Biology 2010 Molecules and cells Vol.30 No.2

Glucagon like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretin hormones released in response to food intake and potentiate insulin secretion from pancreatic ${\beta}$ cells through their distinct yet related G protein-coupled receptors, GLP1R and GIPR. While GLP-1 and GIP exhibit similarity in their N-terminal sequence and overall ${\alpha}$-helical structure, GLP-1 does not bind to GIPR and vice versa. To determine which amino acid residues of these peptide ligands are responsible for specific interaction with their respective receptors, we generated mutant GIP in which several GLP-1-specific amino acid residues were substituted for the original amino acids. The potency of the mutant ligands was examined using HEK293 cells transfected with GLP1R or GIPR expression plasmids together with a cAMP-responsive element-driven luciferase (CRE-luc) reporter plasmid. A mutated GIP peptide in which $Tyr^1$, $Ile^7$, $Asp^{15}$, and $His^{18}$ were replaced by His, Thr, Glu, and Ala, respectively, was able to activate both GLP1R and GIPR with moderate potency. Replacing the original $Tyr^1$ and/or $Ile^7$ in the Nterminal moiety of this mutant peptide allowed full activation of GIPR but not of GLP1R. However, reintroducing $Asp^{15}$ and/or $His^{18}$ in the central ${\alpha}$-helical region did not significantly alter the ligand potency. These results suggest that Tyr/$His^1$ and Ile/$Thr^7$ of GIP/GLP-1 peptides confer differential ligand selectivity toward GIPR and GLP1R.

Tyr1 and Ile7 of Glucose-Dependent Insulinotropic Polypeptide (GIP) Confer Differential Ligand Selectivity toward GIP and Glucagon-like Peptide-1 Receptors

문미진,Hee Young Kim,김신곤,Juri Park,최동섭,황종익,성재영 한국분자세포생물학회 2010 Molecules and cells Vol.30 No.2

Glucagon like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretin hormones released in response to food intake and potentiate insulin secretion from pancreatic β cells through their distinct yet related G protein-coupled receptors, GLP1R and GIPR. While GLP-1 and GIP exhibit similarity in their N-terminal sequence and overall α-helical structure, GLP-1 does not bind to GIPR and vice versa. To determine which amino acid residues of these peptide ligands are responsible for specific interaction with their respective receptors, we generated mutant GIP in which several GLP-1-specific amino acid residues were substituted for the original amino acids. The potency of the mutant ligands was examined using HEK293 cells transfected with GLP1R or GIPR expression plasmids together with a cAMP-responsive element-driven luciferase (CRE-luc) reporter plasmid. A mutated GIP peptide in which Tyr1, Ile7, Asp15, and His18were replaced by His, Thr, Glu, and Ala, respectively, was able to activate both GLP1R and GIPR with moderate potency. Replacing the original Tyr1 and/or Ile7 in the Nterminal moiety of this mutant peptide allowed full activation of GIPR but not of GLP1R. However, reintroducing Asp15 and/or His18 in the central α-helical region did not significantly alter the ligand potency. These results suggest that Tyr/His1 and Ile/Thr7 of GIP/GLP-1 peptides confer differential ligand selectivity toward GIPR and GLP1R.

Glucagon-like peptide-1 and glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes

이승아,이동윤 대한소아내분비학회 2017 Annals of Pediatirc Endocrinology & Metabolism Vol.22 No.1

The prevalence of type 2 diabetes (T2D) is increasing worldwide. Patients with T2D suffer from various diabetes-related complications. Since there are many patients with T2D that cannot be controlled by previously developed drugs, it has been necessary to develop new drugs, one of which is a glucagon-like peptide-1 (GLP-1) based therapy. GLP-1 has been shown to ameliorate diabetes-related conditions by augmenting pancreatic β-cell insulin secretion and having the low risk of causing hypoglycemia. Because of a very short half-life of GLP-1, many researches have been focused on the development of GLP-1 receptor (GLP-1R) agonists with long half-lives such as exenatide and dulaglutide. Now GLP-1R agonists have a variety of dosing-cycle forms to meet the needs of various patients. In this article, we review the physiological features of GLP-1, the effects of GLP-1 on T2D, the features of several GLP-1R agonists, and the therapeutic effect on T2D.

Adenoviral vector-mediated glucagon-like peptide 1 gene therapy improves glucose homeostasis in Zucker diabetic fatty rats

Lee, Yongho,Kwon, Mi Kyong,Kang, Eun Seok,Park, Young Mi,Choi, Seung Ho,Ahn, Chul Woo,Kim, Kyung Sub,Park, Chul Won,Cha, Bong Soo,Kim, Sung Wan,Sung, Je Kyung,Lee, Eun Jig,Lee, Hyun Chul John Wiley Sons, Ltd. 2008 The journal of gene medicine Vol.10 No.3

<B>Background</B><P>Glucagon-like peptide-1 (GLP-1) is a gut-derived incretin hormone that plays an important role in glucose homeostasis. Its functions include glucose-stimulated insulin secretion, suppression of glucagon secretion, deceleration of gastric emptying, and reduction in appetite and food intake. Despite the numerous antidiabetic properties of GLP-1, its therapeutic potential is limited by its short biological half-life due to rapid enzymatic degradation by dipeptidyl peptidase IV. The present study aimed to demonstrate the therapeutic effects of constitutively expressed GLP-1 in an overt type 2 diabetic animal model using an adenoviral vector system.</P><B>Methods</B><P>A novel plasmid (pAAV-ILGLP-1) and recombinant adenoviral vector (Ad-ILGLP-1) were constructed with the cytomegalovirus promoter and insulin leader sequence followed by GLP-1(7–37) cDNA.</P><B>Results</B><P>The results of an enzyme-linked immunosorbent assay showed significantly elevated levels of GLP-1(7–37) secreted by human embryonic kidney cells transfected with the construct containing the leader sequence. A single intravenous administration of Ad-ILGLP-1 into 12-week-old Zucker diabetic fatty (ZDF) rats, which have overt type 2 diabetes mellitus (T2DM), achieved near normoglycemia for 3 weeks and improved utilization of blood glucose in glucose tolerance tests. Circulating plasma levels of GLP-1 increased in GLP-1-treated ZDF rats, but diminished 21 days after treatment. When compared with controls, Ad-ILGLP-1-treated ZDF rats had a lower homeostasis model assessment for insulin resistance score indicating amelioration in insulin resistance. Immunohistochemical staining showed that cells expressing GLP-1 were found in the livers of GLP-1-treated ZDF rats.</P><B>Conclusions</B><P>These data suggest that GLP-1 gene therapy can improve glucose homeostasis in fully developed diabetic animal models and may be a promising treatment modality for T2DM in humans. Copyright © 2007 John Wiley & Sons, Ltd.</P>

Acute Effects of Glucagon-Like Peptide-1 on Hypothalamic Neuropeptide and AMP Activated Kinase Expression in Fasted Rats

SEO, Sanghee,JU, Sunghee,CHUNG, Hyunju,LEE, Dahm,PARK, Seungjoon The Japan Endocrine Society 2008 Endocrine journal Vol.55 No.5

<P>Intracerebroventricular (icv) administration of glucagon-like peptide-1 (GLP-1) inhibits food intake and induces c-fos expression in the hypothalamus. However, the effects of GLP-1 on hypothalamic neuronal activity or neuropeptide mRNA expression are unknown. In this study, we examined the effects of GLP-1 on fasting-induced changes in the expression of hypothalamic orexigenic and anorexigenic neuropeptide. Food intake was significantly inhibited after icv injection of GLP-1 in 48 h fasted rats. Hypothalamic neuropeptide Y (NPY) and agouti-related peptide (AgRP) mRNAs were significantly increased by fasting, whereas icv GLP-1 treatment significantly attenuated these fasting-induced increases. Both proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) mRNA levels were decreased by fasting, while GLP-1 treatment attenuated fasting-induced decreases in POMC and CART expression. We also determined the mRNA levels of AMP-activated kinase (AMPK) and found that fasting resulted in a significant stimulation of hypothalamic AMPKα2 mRNA. Fasting-induced increase in AMPKα2 mRNA was almost completely prevented by GLP-1 treatment. Analysis of phosphorylated AMPKα and acetyl CoA carboxylase showed similar results. Taken together, our observation suggests that the decreased food intake by GLP-1 is caused by preventing the fasting-induced increase in hypothalamic NPY and AgRP and the fasting-induced decrease in hypothalamic POMC and CART. Our results also suggest that the food intake lowering effect of GLP-1 is caused by reversing the fasting-induced increase in hypothalamic AMPK activity. Therefore we conclude that the anorectic effect of GLP-1 seems to be mediated by, at least in part, by the hypothalamus.</P>

복합운동이 폐경 후 비만 여성의 인슐린 저항성, 렙틴, GLP-1에 미치는 영향

곽동호,고수한,하수민,강두왕,김도연 한국여성체육학회 2022 한국여성체육학회지 Vol.36 No.3

The purpose of this study was to investigate the effect of combined exercise program for 11 weeks on insulin resistance, leptin, GLP-1 in post menopause obesity women, aged 55 to 65 years by dividing them into a exercise group(n=12) and control group(n=12). The combined exercise which was composed treadmill and elastic band conducted three times a week for 11 weeks for 60 minutes per session. The intensity of treadmill walking exercise was comprised at 40-49%HRR for 1-4 weeks, 50-59%HRR for 5-8 weeks, and 60-69%HRR for 9-11 weeks. Elastic band exercise were performed with a low intensity of OMNI-RES 3-4 at 1-4 weeks, a medium intensity of OMNI-RES 5-6 at 5-8 weeks, and a high intensity of OMNI-RES 7-8 at 9-11 weeks. Statistical analysis was utilized SPSS 22.0 and p.<05 value was used for significance. We used two-way repeated measures ANOVA to determine the interaction between groups and times. Also, the difference between the results of pre and post parameters was calculated by paired t-test in each groups and independent t-test was utilized for demonstrate the significant difference between exercise group and control group. The results of the glucose, insulin, HOMA-IR showed a interactions between groups and times. The difference between the pre and post exercise periods was significant decreased in the exercise group, and showed significant difference in the amount of variation between groups after 11 weeks. The results of the leptin showed a interactions between groups and times. The difference between the pre and post exercise periods was significant decreased in the exercise group, and showed significant difference in the amount of variation between groups after 11 weeks. The results of the GLP-1 showed a interactions between groups and times. The difference between the pre and post exercise periods was significant decreased in the exercise group, and showed significant difference in the amount of variation between groups after 11 weeks. Therefore, it is concluded that 11 weeks of combined exercise including treadmill walking and elastic band exercise had a positive effect on insulin resistance, leptin, GLP-1 in post menopause obesity women. 본 연구는 11주간의 복합운동이 인슐린 저항성, 렙틴, GLP-1에 미치는 영향을 구명하기 위하여 만 55세 이 상 65세 미만의 폐경이 2년 이상 지난 비만 여성을 대상으로 운동군(n=12), 대조군(n=12)으로 구분하여 실시 하였다. 트레드밀 걷기운동과 탄력밴드운동으로 구성된 복합운동은 11주간 주 3회, 1회당 60분으로 실시하였 다. 트레드밀을 이용한 걷기운동 방법은 1-4주는 40-49%HRR, 5-8주는 50-59%HRR, 9-11주는 60-69%HRR로 실시하였다. 탄력밴드운동은 1-4주는 OMNI-RES 3-4의 저강도, 5-8주는 OMNI-RES 5-6의 중강도, 9-11주는 OMNI-RES 7-8의 고강도로 실시하였다. 측정 변인들에 대한 그룹 및 시기 간 상호작용을 검증하기 위하여 two-way repeated measures ANOVA로 처리하였고, 측정된 자료의 그룹 내 차이는 paired t-test, 그룹 간 차이는 independent t-test를 실시하였다. 통계적 유의수준은 .05로 설정하여 다음과 같은 결과를 얻었다. 인슐린 저항 성에 대하여 글루코스, 인슐린, HOMA-IR은 그룹×시기 간 상호작용 효과가 나타났다. 운동 전·후 시기 간 차 이에서 운동군이 11주 후 유의하게 감소하였으며 그룹 간 차이는 11주 후 변화량에서 유의한 차이가 나타났 다. 또한, 렙틴은 그룹×시기 간 상호작용 효과가 나타났고, 운동 전·후 시기 간 차이에서 운동군이 11주 후 유의하게 감소하였으며 그룹 간 차이는 11주 후 변화량에서 유의한 차이가 나타났다. GLP-1은 그룹×시기 간 상호작용 효과가 나타났고, 시기 간 주효과가 나타났다. 운동 전·후 시기 간 차이에서 운동군이 11주 후 유의 하게 감소하였으며 그룹 간 차이는 11주 후 변화량에서 유의한 차이가 나타났다. 이상의 결과를 종합해 볼 때 11주간의 트레드밀 걷기운동과 탄력밴드운동으로 구성된 복합운동이 폐경 후 비만 중년여성의 인슐린 저 항성, 렙틴, GLP-1에 긍정적인 영향을 미친 것으로 사료 된다.

Design of chimeric GLP-1A using oligomeric bile acids to utilize transporter-mediated endocytosis for oral delivery

Seho Kweon,Jun‑Hyuck Lee,양성빈,박성진,Laxman Subedi,Jung‑Hyun Shim,Seung‑Sik Cho,Jeong Uk Choi,Youngro Byun,박주호,박진우 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Despite the effectiveness of glucagon-like peptide-1 agonist (GLP-1A) in the treatment of diabetes, its large molecular weight and high hydrophilicity result in poor cellular permeability, thus limiting its oral bioavailability. To address this, we developed a chimeric GLP-1A that targets transporter-mediated endocytosis to enhance cellular permeability to GLP-1A by utilizing the transporters available in the intestine, particularly the apical sodium-dependent bile acid transporter (ASBT). Methods In silico molecular docking and molecular dynamics simulations were used to investigate the binding interactions of mono-, bis-, and tetra-deoxycholic acid (DOCA) (monoDOCA, bisDOCA, and tetraDOCA) with ASBT. After synthesizing the chimeric GLP-1A-conjugated oligomeric DOCAs (mD-G1A, bD-G1A, and tD-G1A) using a maleimide reaction, in vitro cellular permeability and insulinotropic effects were assessed. Furthermore, in vivo oral absorption in rats and hypoglycemic effect on diabetic db/db mice model were evaluated. Results In silico results showed that tetraDOCA had the lowest interaction energy, indicating high binding affinity to ASBT. Insulinotropic effects of GLP-1A-conjugated oligomeric DOCAs were not different from those of GLP-1A-Cys or exenatide. Moreover, bD-G1A and tD-G1A exhibited improved in vitro Caco-2 cellular permeability and showed higher in vivo bioavailability (7.58% and 8.63%) after oral administration. Regarding hypoglycemic effects on db/db mice, tD-G1A (50 μg/kg) lowered the glucose level more than bD-G1A (50 μg/kg) compared with the control (35.5% vs. 26.4%). Conclusion GLP-1A was conjugated with oligomeric DOCAs, and the resulting chimeric compound showed the potential not only for glucagon-like peptide-1 receptor agonist activity but also for oral delivery. These findings suggest that oligomeric DOCAs can be used as effective carriers for oral delivery of GLP-1A, offering a promising solution for enhancing its oral bioavailability and improving diabetes treatment.