مستقبل الپپتيد المشابه للگلوكاگون-1

GLP1R
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesGLP1R, entrez:2740, glucagon-like peptide 1 receptor, GLP-1, GLP-1-R, GLP-1R, glucagon like peptide 1 receptor
External IDsOMIM: 138032 MGI: 99571 HomoloGene: 1558 GeneCards: GLP1R
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NR_136562، NR_136563 NM_002062، NR_136562، NR_136563

NM_021332

RefSeq (protein)

XP_016866239، XP_016866240 NP_002053، XP_016866239، XP_016866240

NP_067307

Location (UCSC)n/aChr 17: 31.12 – 31.16 Mb
PubMed search[2][3]
Wikidata
View/Edit HumanView/Edit Mouse

مستقبل الپپتيد المشابه للگلوكاگون-1 (إنگليزية: Glucagon-like peptide-1 receptor، اختصاراً GLP1R)، هو پروتين مستقبل يوجد في خلايا بيتا بالپنكرياس وفي عصبونات المخ. لدى البشر، تخلق هذه المستقبلات بواسطة جين GLP1R، الموجود على الكروموسوم 6.[4][5] وهو ضمن عائلة مستقبلات الگلوكاگون للمستقبلات المقترنة بالپروتين جي.[6] يتألف مستقبل الپپتيد المشابه للگلوكاگون-1 من نطاقين، وخارج خلوي واحد (ECD) يربط اللولب الطرفي-سي مع GLP-1،[7] ونطاق غشائي واحد (TMD) [8] يربط المنطقة الطرفية إن GLP-1.[9][10][11] In the TMD domain there is a fulcrum of polar residues that regulates the biased signaling of the receptor [9] while the transmembrane helical boundaries[12] and extracellular surface are a trigger for biased agonism.[10]

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رابط المستقبل البشرية

GLP1R binds glucagon-like peptide-1 (GLP1) and glucagon as its natural endogenous agonists.[13]

Receptor agonists:

Receptor antagonists:

  • [9-39]-GLP-1
  • "T-0632"[13]
  • "GLP1R0017"[15]

Receptor positive allosteric modulators:

Receptor negative allosteric modulators:


الوظيفة والإمكانات العلاجية

GLP1R is known to be expressed in pancreatic beta cells. Activated GLP1R stimulates the adenylyl cyclase pathway which results in increased insulin synthesis and release of insulin.[17] Consequently, GLP1R has been a target for developing drugs usually referred to as GLP1R agonists to treat diabetes mellitus.[18] Exendin-4 is one of the peptides used therapeutically to treat diabetes, and its biological binding mode to the GLP-1R has been demonstrated using genetically engineered amino acids.[14]

GLP1R is also expressed in the brain[19] where it is involved in the control of appetite.[20] Furthermore, mice that over express GLP1R display improved memory and learning.[21]

Stretch responsive vagal neurons in the stomach and intestines also express GLP1R.[22] GLP1R neurons particularly and densely innervate stomach muscle and can communicate with additional organ systems changing breathing and heart rate due to activation.[22]

مرض هنتنگتون

The diabetic, pancreatic, and neuroprotection implications of GLP1R are also thought to be potential therapies for treating the diabetes and energy metabolism abnormalities associated with Huntington's disease affecting the brain and periphery. Exendin-4, an FDA-approved antidiabetic glucagon-like peptide 1 (GLP-1) receptor agonist, has been tested in mice with the mutated human huntingtin protein showing neurodegenerative changes, motor dysfunction, poor energy metabolism, and high blood glucose levels. Exendin-4 (Ex-4) treatment reduced the accumulation of mutated human huntingtin protein aggregates, improved motor function, extended the survival time, improved glucose regulation, and decreased brain and pancreas pathology.[23]

Exendin-4 increases beta cell mass in the pancreatic islets to improve the release of insulin to ultimately increase glucose uptake. The mechanism regarding this insulin increase involves Ex-4 and GLP-1. When the islets in the pancreas are exposed to GLP-1, there is an increased expression of the anti-apoptotic gene bcl-2 and decreased expression of pro-apoptotic genes bax and caspase-3, which leads to greater cell survival. GLP-1 binding to its G protein-coupled receptor activates various different pathways including the growth factor receptor and is coupled to pathways stimulating mitogenesis. Some of these pathways include Rap, Erk1/2, MAPK, B-RAF, PI3-K, cAMP, PKA, and TORC2 that are activated to initiate exocytosis, proinsulin gene expression and translation, increase insulin biosynthesis, and genetically increase beta cell proliferation and neogenesis. The GLP-1R is a G protein-coupled receptor that is dependent on glucose and GLP-1 is a peptide hormone that acts directly on the beta cell to stimulate insulin secretion by activating signal transduction when glucose is present. When glucose is not present, this receptor no longer couples to stimulate insulin secretion in order to prevent hypoglycemia.[24]

Relating glucose metabolism and insulin sensitivity back to Huntington's disease, increased insulin release and beta cell proliferation by a GLP-1 agonist, Ex-4, helps combat the damage done by mutant htt in peripheral tissues. Htt aggregation decreases beta cell mass and thus impairs insulin release and increases blood glucose levels. Disruption of glycemic homeostasis then affects nutrient availability to neurons and alters neuron function contributing to neurodegeneration and motor problems seen in Huntington's disease. The health of the nervous system is related to metabolic health, thus a diabetes medication as a Huntington's disease treatment is a potential treatment. Ex-4 easily crosses the blood-brain barrier and GLP-1 and Ex-4 have been shown to act on neurons in the brain by exerting neuroprotective actions.[23]

In studies with Huntington's disease mice, daily treatments of Ex-4 significantly reduced glucose levels compared to those mice treated with saline. It also increased insulin sensitivity by about 50%, improved insulin-stimulated glucose uptake, and protect pancreatic beta cell function. Huntington's disease has also been linked to imbalances in leptin and ghrelin levels. Ex-4 restored ghrelin levels and also lowered leptin levels allowing Huntington's disease mice to eat more and counteract symptomatic weight loss. This treatment restored beta cell cells and islet structure, reduce mutated human huntingtin aggregates in the brain and pancreas, and also improve motor function seen by the increased activity level of the mice. Improvements were found in the areas of the body that expressed GLP-1R. In addition to its other effects on the Huntington's disease mouse model, daily treatment of Ex-4, the GLP-1R agonist, significantly delayed the onset of mortality and extended the lifespan by approximately one month.[23]

انظر أيضاً

المصادر

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  3. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
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  13. ^ أ ب ت ث ج ح خ د Maguire JJ, Davenport AP. "GLP-1 receptor". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. Retrieved 13 September 2015.
  14. ^ أ ب Koole C, Reynolds CA, Mobarec JC, Hick C, Sexton PM, Sakmar TP (April 2017). "Genetically encoded photocross-linkers determine the biological binding site of exendin-4 peptide in the N-terminal domain of the intact human glucagon-like peptide-1 receptor (GLP-1R)". The Journal of Biological Chemistry. 292 (17): 7131–7144. doi:10.1074/jbc.M117.779496. PMC 5409479. PMID 28283573.
  15. ^ Biggs EK, Liang L, Naylor J, Madalli S, Collier R, Coghlan MP, et al. (March 2018). "Development and characterisation of a novel glucagon like peptide-1 receptor antibody". Diabetologia. 61 (3): 711–721. doi:10.1007/s00125-017-4491-0. PMC 5890879. PMID 29119245.
  16. ^ O'Brien A, Andrews S, Baig AH, Bortolato A, Brown JH, Brown GA, et al. (2019-08-09). "Identification of a novel allosteric GLP–1R antagonist HTL26119 using structure-based drug design". Bioorganic & Medicinal Chemistry Letters. 29 (20): 126611. doi:10.1016/j.bmcl.2019.08.015. PMID 31447084.
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قراءات إضافية


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وصلات خارجية