Project description:To gain insight into the biological functions of the highly expressed GLP-1R in Brunnerâs glands, transcriptome analyses were conducted in male GLP-1R-/- and wild-type control mice. Analyses were performed 6 hours after a single s.c. dose of exendin-4 (1.0mg/kg s.c.), following 18 hours of two doses of exendin-4 (1.0 mg/kg s.c., administered at 0 and 9 hours), and in untreated controls. Brunnerâs glands were isolated by laser capture micro dissection and extracted total RNA was used for microarray profiling. A total of 18 samples consisting of laser captured microdissected Brunner's glands from individual male GLP-1R-/- and wild-type (CD-1) mice. Before the isolation of Brunner's glands, mice were dosed with exendin-4 for 6 and 18 hours. The extracted total RNA from Brunner's glands were compared by full transcriptome profiling.
Project description:To gain insight into the biological functions of the highly expressed GLP-1R in Brunner’s glands, transcriptome analyses were conducted in male GLP-1R-/- and wild-type control mice. Analyses were performed 6 hours after a single s.c. dose of exendin-4 (1.0mg/kg s.c.), following 18 hours of two doses of exendin-4 (1.0 mg/kg s.c., administered at 0 and 9 hours), and in untreated controls. Brunner’s glands were isolated by laser capture micro dissection and extracted total RNA was used for microarray profiling.
Project description:Gut intraepithelial lymphocytes (IELs) are one of the few immune cell populations in the body that expresses glucagon-like 1 receptors (GLP-1R). To test the potential effects of GLP-1 on gut IEL function, we performed bulk RNA-seq on gut IELs isolated from C57BL/6J mice treated with anti-CD3 and with or without exendin-4 for 3 hours.
Project description:Early drivers of Type 2 diabetes mellitus (T2D) include ectopic fat accumulation, especially in the liver, that significantly impairs insulin sensitivity. In a T2D setting, GLP-1R/GCGR dual agonists have been shown to reduce glycaemia, body weight and hepatic steatosis. We utilized cotadutide, a well characterized GLP-1R/GCGR dual-agonist, to demonstrate improved insulin sensitivity during hyperinsulinemic euglycemic clamp following sub-chronic dosing in male, diet-induced obese mice. Phosphoproteomic analyses of insulin stimulated liver from cotadutide treated diet-induced obese (DIO) mice identified novel phosphorylation sites on key insulin signalling pathway proteins associated with improved insulin sensitivity. Cotadutide or GCGR monoagonist treatment also resulted in specific increased brown adipose tissue (BAT) insulin-stimulated glucose uptake, while GLP-1R monoagonist only showed a weak effect. BAT from cotadutide treated mice had induction of UCP-1 protein, increased mitochondrial area and a transcriptomic profile of increased fat oxidation and mitochondrial activity. Finally, the cotadutide-induced improvement in insulin sensitivity was associated with reduced insulin secretion from isolated pancreatic islet β-cells indicating reduced insulin secretory demand. Thus, GLP-1R/GCGR dual agonism provides multimodal efficacy to decrease hepatic steatosis and consequently improve insulin sensitivity, in concert with recovery of endogenous β-cell function and reduced insulin demand. This substantiates GLP-1R/GCGR dual-agonism as a novel and effective T2D treatment
Project description:Glucose-dependent insulinotropic polypeptide receptor (GIPR) and glucagon-like peptide 1 receptor (GLP-1R) are expressed in the central nervous system (CNS) and regulate food intake. Here, we demonstrate that a peptide-antibody conjugate that blocks GIPR while simultaneously activating GLP-1R (GIPR-Ab/GLP-1) requires both CNS GIPR and CNS GLP-1R for additive effects on body weight loss in obese, primarily male, mice. Moreover, dulaglutide produces greater weight loss in CNS GIPR KO mice compared to WT mice, and the extent of weight loss achieved with dulaglutide + GIPR-Ab is attenuated in CNS GIPR KO mice. WT mice treated with GIPR-Ab/GLP-1 or CNS GIPR KO mice exhibit similar changes in gene expression related to tissue remodeling, lipid metabolism, and inflammation in white adipose tissue and liver. Moreover, GIPR-Ab/GLP-1 is detected in circumventricular organs in the brain and activates c-FOS in downstream neural substrates involved in appetite regulation. Hence, both CNS GIPR and GLP-1R signaling are required for the full effect of a GIPR-Ab/GLP-1 peptide-antibody conjugate, with loss of CNS GIPR activity potentiating the actions of GLP-1R agonism.
Project description:Early drivers of Type 2 diabetes mellitus (T2D) include ectopic fat accumulation, especially in the liver, that significantly impairs insulin sensitivity. In a T2D setting, GLP-1R/GCGR dual agonists have been shown to reduce glycaemia, body weight and hepatic steatosis. We utilized cotadutide, a well characterized GLP-1R/GCGR dual-agonist, to demonstrate improved insulin sensitivity during hyperinsulinemic euglycemic clamp following sub-chronic dosing in male, diet-induced obese mice. Cotadutide or GCGR monoagonist treatment resulted in specific increased brown adipose tissue (BAT) insulin-stimulated glucose uptake, while GLP-1R monoagonist only showed a weak effect. BAT from cotadutide treated mice had induction of UCP-1 protein, increased mitochondrial area and a transcriptomic profile of increased fat oxidation and mitochondrial activity. Thus, GLP-1R/GCGR dual agonism provides multimodal efficacy to decrease hepatic steatosis and consequently improve insulin sensitivity, in concert with recovery of endogenous β-cell function and reduced insulin demand. This substantiates GLP-1R/GCGR dual-agonism as a novel and effective T2D treatment.
Project description:Agonists and antagonists of the glucose-dependent insulinotropic polypeptide receptor (GIPR) enhance body weight loss induced by glucagon-like peptide-1 receptor (GLP-1R) agonism. But while GIPR agonism decreases body weight and food intake in a GLP-1R-independent manner via GABAergic GIPR+ neurons, it remains unclear whether GIPR antagonism affects energy metabolism via a similar mechanism. Here we show that the body weight and food intake reducing effects of GIPR antagonism vanish in mice with global loss of either Gipr or Glp-1r but are preserved in mice with loss of Gipr in either GABAergic or peripheral neurons. RNA-sequencing shows opposing effects of GIPR agonism and antagonism in the hindbrain, with antagonism, but not agonism, mimicking GLP-1R signaling, and with GIPR antagonism and GLP-1R agonism both regulating gene programs implicated in synaptic plasticity. Collectively, we show that GIPR agonism and antagonism decrease body weight via different mechanisms, with GIPR antagonism, unlike agonism, depending on functional GLP-1R signaling.
Project description:Gut intraepithelial lymphocytes (IELs) are one of the few immune cell populations in the body that expresses glucagon-like 1 receptors (GLP-1R). To test the potential effects of GLP-1 on the gut microbiota through the gut IEL GLP-1R, we performed 16s rRNA seq on the DNA isolated from the fecal pellet of Lck-Cre; Glp1rfl/fl mice (Glp1rTcell-/-) or controls (Glp1rTcell+/+) fed a high-fat diet (HFD) for 12 weeks followed by 1 week of HFD plus semaglutide (10 ug/kg) or vehicle treatment. Fecal pellets from a group of age-matched, sex-matched control mice were included as a chow control group.
Project description:GLP-1 analogues, such as exendin-4, preserve functional β-cell mass in various model systems and are revolutionising management of type 2 diabetes. Yet, comparatively little is known about effectiveness in the face of severe β-cell depletion. Moreover, direct and sequential effects of exendin-4 on islet-specific gene expression over time in vivo are not well characterised. To address these issues and others, we have examined the time-dependent effects of exendin-4 treatment on β-cell mass regulation alongside accompanying changes in islet gene expression in vivo. Context-dependent actions were assessed by comparing effects on normal islets and also following massive toxigenetic β-cell ablation in pIns-MYCERTAM transgenic mice in vivo. Despite over 90% loss of β-cell mass, exendin-4 treatment normalised blood glucose and insulin levels in hyperglycaemic mice, though benefits rapidly waned on withdrawal of treatment. As exendin-4 did not arrest the decline in β-cell mass or turnover in this study, we could directly isolate effects on function of surviving β-cells. Improved glucose homeostasis was associated with dynamic changes in multiple islet genes and pathways in vivo favouring glucose-stimulated insulin secretion, such as Irs2, Pdx1, Sox4, glucokinase, and glycolysis pathway. Several key growth pathways and epigenetic regulators were also differentially expressed. Thus, even in the face of extensive β-cell loss exendin-4 can markedly improve hyperglycaemia by differential gene expression in surviving islet cells. Activation of MYCERTAM was achieved through administration of 1mg of 4 hydroxytamoxifen (4OHT; Sigma-Aldrich, St. Louis, MO) by daily intraperitoneal injection. To assess the effect of exendin-4 on MYCER-induced hyperglycaemia, mice were given either twice-daily subcutaneous (sc) injections of exendin-4 (50ug/kg dissolved in 5mls water), or equivalent volumes of water vehicle, starting 2 days prior to 4OHT injections. For microarray analyses parallel mouse experiments were set up using 8-12 week old pIns-MYCERTAM male mice either treated with 4OHT or vehicle (peanut oil) and exendin-4 or vehicle, as described, for 4, 8, 16, 32 and 72 hours (n=3 for each time point and for each of four conditions; 4OHT and exendin-4 treated, peanut oil and exendin-4 treated, 4OHT and water treated, peanut oil and water treated). !Sample_data_processing = After the quality control step, the following 8 samples out of 60 showing poor reproducibility were excluded from our further study: GSM930242, GSM930247, GSM930251, GSM930263, GSM930264, GSM930289, GSM930291, GSM930298.