RESUMO
Semaglutide, a glucagon-like peptide 1 (GLP-1) analog, induces weight loss, lowers glucose levels, and reduces cardiovascular risk in patients with diabetes. Mechanistic preclinical studies suggest weight loss is mediated through GLP-1 receptors (GLP-1Rs) in the brain. The findings presented here show that semaglutide modulated food preference, reduced food intake, and caused weight loss without decreasing energy expenditure. Semaglutide directly accessed the brainstem, septal nucleus, and hypothalamus but did not cross the blood-brain barrier; it interacted with the brain through the circumventricular organs and several select sites adjacent to the ventricles. Semaglutide induced central c-Fos activation in 10 brain areas, including hindbrain areas directly targeted by semaglutide, and secondary areas without direct GLP-1R interaction, such as the lateral parabrachial nucleus. Automated analysis of semaglutide access, c-Fos activity, GLP-1R distribution, and brain connectivity revealed that activation may involve meal termination controlled by neurons in the lateral parabrachial nucleus. Transcriptomic analysis of microdissected brain areas from semaglutide-treated rats showed upregulation of prolactin-releasing hormone and tyrosine hydroxylase in the area postrema. We suggest semaglutide lowers body weight by direct interaction with diverse GLP-1R populations and by directly and indirectly affecting the activity of neural pathways involved in food intake, reward, and energy expenditure.
Assuntos
Peso Corporal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Peptídeos Semelhantes ao Glucagon/farmacologia , Vias Neurais/efeitos dos fármacos , Animais , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Receptor do Peptídeo Semelhante ao Glucagon 1/efeitos dos fármacos , Camundongos , RatosRESUMO
Oral administration of therapeutic peptides is hindered by poor absorption across the gastrointestinal barrier and extensive degradation by proteolytic enzymes. Here, we investigated the absorption of orally delivered semaglutide, a glucagon-like peptide-1 analog, coformulated with the absorption enhancer sodium N-[8-(2-hydroxybenzoyl) aminocaprylate] (SNAC) in a tablet. In contrast to intestinal absorption usually seen with small molecules, clinical and preclinical dog studies revealed that absorption of semaglutide takes place in the stomach, is confined to an area in close proximity to the tablet surface, and requires coformulation with SNAC. SNAC protects against enzymatic degradation via local buffering actions and only transiently enhances absorption. The mechanism of absorption is shown to be compound specific, transcellular, and without any evidence of effect on tight junctions. These data have implications for understanding how highly efficacious and specific therapeutic peptides could be transformed from injectable to tablet-based oral therapies.
Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Peptídeos Semelhantes ao Glucagon/farmacologia , Absorção Intestinal , Estômago/fisiologia , Administração Oral , Adolescente , Adulto , Idoso , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cães , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/ultraestrutura , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Peptídeos Semelhantes ao Glucagon/administração & dosagem , Peptídeos Semelhantes ao Glucagon/farmacocinética , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Ratos , Estômago/efeitos dos fármacos , Fatores de Tempo , Adulto JovemRESUMO
AIMS: Glucagon-like peptide-1 (GLP-1) is an incretin hormone which stimulates insulin release and inhibits glucagon secretion from the pancreas in a glucose-dependent manner. Incretin-based therapies, consisting of GLP-1 receptor (GLP-1R) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors, are used for the treatment of type 2 diabetes (T2D). Immunohistochemical studies for GLP-1R expression have been hampered previously by the use of unspecific polyclonal antibodies. This study aimed to assess the expression levels of GLP-1R in a set of T2D donor samples obtained via nPOD. METHODS: This study used a new monoclonal antibody to assess GLP-1R expression in pancreatic tissue from 23 patients with T2D, including 7 with a DPP-4 inhibitor and 1 with a history of GLP-1R agonist treatment. A software-based automated image analysis algorithm was used for quantitating intensities and area fractions of GLP-1R positive compartments. RESULTS: The highest intensity GLP-1R immunostaining was seen in beta-cells in islets (average signal intensity, 76.1 [±8.1]). GLP-1R/insulin double-labelled single cells or small clusters of cells were also frequently located within or in close vicinity of ductal epithelium in all samples and with the same GLP-1R immunostaining intensity as found in beta-cells in islets. In the exocrine pancreas a large proportion of acinar cells expressed GLP-1R with a 3-fold lower intensity of immunoreactivity as compared to beta-cells (average signal intensity 25.5 [±3,3]). Our studies did not unequivocally demonstrate GLP-1R immunoreactivity on normal-appearing ductal epithelium. Pancreatic intraepithelial neoplasia (PanINs; a form of non-invasive pancreatic ductular neoplasia) was seen in most samples, and a minority of these expressed low levels of GLP-1R. CONCLUSION: These data confirm the ubiquity of early stage PanIN lesions in patients with T2D and do not support the hypothesis that incretin-based therapies are associated with progression towards the more advanced stage PanIN lesions.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Células Secretoras de Insulina/metabolismo , Pâncreas/metabolismo , Adolescente , Adulto , Idoso , Anticorpos Monoclonais , Especificidade de Anticorpos , Biomarcadores/metabolismo , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/patologia , Feminino , Glucagon/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Humanos , Hipoglicemiantes/uso terapêutico , Processamento de Imagem Assistida por Computador , Imuno-Histoquímica , Incretinas/uso terapêutico , Insulina/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/patologia , Masculino , Pessoa de Meia-Idade , Pâncreas/efeitos dos fármacos , Pâncreas/patologia , Bancos de Tecidos , Adulto JovemRESUMO
One of the major histopathological hallmarks of Alzheimer's disease (AD) is cerebral deposits of extracellular ß-amyloid peptides. Preclinical studies have pointed to glucagon-like peptide 1 (GLP-1) receptors as a potential novel target in the treatment of AD. GLP-1 receptor agonists, including exendin-4 and liraglutide, have been shown to promote plaque-lowering and mnemonic effects of in a number of experimental models of AD. Transgenic mouse models carrying genetic mutations of amyloid protein precursor (APP) and presenilin-1 (PS1) are commonly used to assess the pharmacodynamics of potential amyloidosis-lowering and pro-cognitive compounds. In this study, effects of long-term liraglutide treatment were therefore determined in two double APP/PS1 transgenic mouse models of Alzheimer's disease carrying different clinical APP/PS1 mutations, i.e. the 'London' (hAPPLon/PS1A246E) and 'Swedish' mutation variant (hAPPSwe/PS1ΔE9) of APP, with co-expression of distinct PS1 variants. Liraglutide was administered in 5 month-old hAPPLon/PS1A246E mice for 3 months (100 or 500 ng/kg/day, s.c.), or 7 month-old hAPPSwe/PS1ΔE9 mice for 5 months (500 ng/kg/day, s.c.). In both models, regional plaque load was quantified throughout the brain using stereological methods. Vehicle-dosed hAPPSwe/PS1ΔE9 mice exhibited considerably higher cerebral plaque load than hAPPLon/PS1A246E control mice. Compared to vehicle-dosed transgenic controls, liraglutide treatment had no effect on the plaque levels in hAPPLon/PS1A246E and hAPPSwe/PS1ΔE9 mice. In conclusion, long-term liraglutide treatment exhibited no effect on cerebral plaque load in two transgenic mouse models of low- and high-grade amyloidosis, which suggests differential sensitivity to long-term liraglutide treatment in various transgenic mouse models mimicking distinct pathological hallmarks of AD.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Precursor de Proteína beta-Amiloide/genética , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Liraglutida/uso terapêutico , Mutação , Placa Amiloide/tratamento farmacológico , Presenilina-1/genética , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Humanos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Liraglutida/farmacologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Placa Amiloide/genética , Placa Amiloide/patologiaAssuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Hipoglicemia/induzido quimicamente , Insulinoma/complicações , Neoplasias Pancreáticas/complicações , Receptores de Glucagon/agonistas , Diabetes Mellitus Tipo 2/complicações , Feminino , Peptídeo 1 Semelhante ao Glucagon/efeitos adversos , Peptídeo 1 Semelhante ao Glucagon/uso terapêutico , Receptor do Peptídeo Semelhante ao Glucagon 1 , Humanos , Insulina/sangue , Insulinoma/sangue , Insulinoma/cirurgia , Liraglutida , Pessoa de Meia-Idade , Neoplasias Pancreáticas/sangue , Neoplasias Pancreáticas/cirurgia , Receptores de Glucagon/análise , Índice de Gravidade de DoençaRESUMO
Glucagon-like peptide 1 (GLP-1) analogs are increasingly being used in the treatment of type 2 diabetes. It is clear that these drugs lower blood glucose through an increase in insulin secretion and a lowering of glucagon secretion; in addition, they lower body weight and systolic blood pressure and increase heart rate. Using a new monoclonal antibody for immunohistochemistry, we detected GLP-1 receptor (GLP-1R) in important target organs in humans and monkeys. In the pancreas, GLP-1R was predominantly localized in ß-cells with a markedly weaker expression in acinar cells. Pancreatic ductal epithelial cells did not express GLP-1R. In the kidney and lung, GLP-1R was exclusively expressed in smooth muscle cells in the walls of arteries and arterioles. In the heart, GLP-1R was localized in myocytes of the sinoatrial node. In the gastrointestinal tract, the highest GLP-1R expression was seen in the Brunner's gland in the duodenum, with lower level expression in parietal cells and smooth muscle cells in the muscularis externa in the stomach and in myenteric plexus neurons throughout the gut. No GLP-1R was seen in primate liver and thyroid. GLP-1R expression seen with immunohistochemistry was confirmed by functional expression using in situ ligand binding with (125)I-GLP-1. In conclusion, these results give important new insight into the molecular mode of action of GLP-1 analogs by identifying the exact cellular localization of GLP-1R.
Assuntos
Anticorpos Monoclonais/química , Insulina/metabolismo , Receptores de Glucagon/metabolismo , Animais , Pressão Sanguínea , Peso Corporal , Linhagem Celular , Cricetinae , Duodeno/metabolismo , Exenatida , Glucagon/metabolismo , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Peptídeo 1 Semelhante ao Glucagon/química , Receptor do Peptídeo Semelhante ao Glucagon 1 , Haplorrinos , Frequência Cardíaca , Humanos , Secreção de Insulina , Ligantes , Liraglutida , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Peptídeos/química , Ligação Proteica , Distribuição Tecidual , Transfecção , Peçonhas/químicaRESUMO
Epidermal growth factor receptor (EGFR) is a validated therapeutic target in cancer and EGFR antagonists with greater effectiveness than existing clinical agents remain of interest. Here, we report a novel approach based on Sym004, a mixture of two anti-EGFR monoclonal antibodies directed against distinct nonoverlapping epitopes in EGFR extracellular domain III. Like anti-EGFR monoclonal antibodies in current clinical use, Sym004 inhibits cancer cell growth and survival by blocking ligand-binding receptor activation and phosphorylation and downstream receptor signaling. However, unlike the other antibodies, Sym004 induces rapid and efficient removal of the receptor from the cancer cell surface by triggering EGFR internalization and degradation. Compared with reference anti-EGFR monoclonal antibodies, Sym004 exhibited more pronounced growth inhibition in vitro and superior efficacy in vivo. Together, these findings illustrate a strategy to target EGFR more effectively than existing clinical antibodies.
Assuntos
Anticorpos Monoclonais/farmacologia , Receptores ErbB/antagonistas & inibidores , Neoplasias/terapia , Animais , Anticorpos Monoclonais/imunologia , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Regulação para Baixo , Sinergismo Farmacológico , Epitopos/imunologia , Receptores ErbB/imunologia , Receptores ErbB/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias/enzimologia , Fosforilação , Estrutura Terciária de Proteína , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Trefoil factors (TFFs) are essential for protection and restitution of the gastrointestinal mucosa but many aspects of TFF biology are unclear. Our aim was to compare the localization of endogenous TFFs and binding sites for injected TFF3 in the colon of healthy and colitic mice and to study the effect of TFF3 on dextrane sulfate sodium (DSS)-induced colitis in mice. Expression of endogenous TFF1-3 was examined by in situ hybridization and immunohistochemistry, and the distribution of intravenously, intraperitoneally, and subcutaneously administered (125)I-TFF3 by autoradiography and gamma-counting. The effect of systemically administered TFF3 on DSS-induced colitis was assessed. We found increased expression of endogenous TFF3 and increased binding of injected (125)I-TFF3 in the colon of animals with DSS-induced colitis. The distribution of intraperitoneally and subcutaneously administered (125)I-TFF3 was comparable. Systemic administration of the peptides reduced the severity of colitis. Expression of endogenous TFF3 and binding of systemically administered TFF3 are increased in DSS-induced colitis. Systemic administration of TFF3 attenuates the disease. These findings suggest a role of TFF3 in mucosal protection.