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The arcuate nucleus mediates GLP-1 receptor agonist liraglutide-dependent weight loss.

ABSTRACT: Liraglutide is a glucagon-like peptide-1 (GLP-1) analog marketed for the treatment of type 2 diabetes. Besides lowering blood glucose, liraglutide also reduces body weight. It is not fully understood how liraglutide induces weight loss or to what degree liraglutide acts directly in the brain. Here, we determined that liraglutide does not activate GLP-1-producing neurons in the hindbrain, and liraglutide-dependent body weight reduction in rats was independent of GLP-1 receptors (GLP-1Rs) in the vagus nerve, area postrema, and paraventricular nucleus. Peripheral injection of fluorescently labeled liraglutide in mice revealed the presence of the drug in the circumventricular organs. Moreover, labeled liraglutide bound neurons within the arcuate nucleus (ARC) and other discrete sites in the hypothalamus. GLP-1R was necessary for liraglutide uptake in the brain, as liraglutide binding was not seen in Glp1r(-/-) mice. In the ARC, liraglutide was internalized in neurons expressing proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART). Electrophysiological measurements of murine brain slices revealed that GLP-1 directly stimulates POMC/CART neurons and indirectly inhibits neurotransmission in neurons expressing neuropeptide Y (NPY) and agouti-related peptide (AgRP) via GABA-dependent signaling. Collectively, our findings indicate that the GLP-1R on POMC/CART-expressing ARC neurons likely mediates liraglutide-induced weight loss.

SUBMITTER: Secher A

PROVIDER: S-EPMC4215190 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

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The arcuate nucleus mediates GLP-1 receptor agonist liraglutide-dependent weight loss.

Secher Anna A Jelsing Jacob J Baquero Arian F AF Hecksher-Sørensen Jacob J Cowley Michael A MA Dalbøge Louise S LS Hansen Gitte G Grove Kevin L KL Pyke Charles C Raun Kirsten K Schäffer Lauge L Tang-Christensen Mads M Verma Saurabh S Witgen Brent M BM Vrang Niels N Bjerre Knudsen Lotte L

The Journal of clinical investigation 20140909 10

Liraglutide is a glucagon-like peptide-1 (GLP-1) analog marketed for the treatment of type 2 diabetes. Besides lowering blood glucose, liraglutide also reduces body weight. It is not fully understood how liraglutide induces weight loss or to what degree liraglutide acts directly in the brain. Here, we determined that liraglutide does not activate GLP-1-producing neurons in the hindbrain, and liraglutide-dependent body weight reduction in rats was independent of GLP-1 receptors (GLP-1Rs) in the v ...[more]

PMID: 25202980

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Project description:B6.Cg-Lep ob/ob mice females were surgically implanted in an age of 10-12 weeks with Alzet osmotic mini pumps (model 1002, 0,25l/h, Cupertino, CA, USA) in two groups of ten mice each to perform continuous subcutaneous infusions of Dulbecco's phosphate buffered saline (vehicle; n = 8) or GLP-1 (GLP-1; n = 9) agonist Liraglutide (Victoza, batch# CS6C214, Novo Nordisk A/S, Bagsvaerd, Denmark) to investigate the effects of the respective treatment on peri-gonadal epididymal white adipose tissue gene expression. Vehicle or Liraglutide at a dose of 600 g/kg/d were continuously infused (at a dose of 600 g/kg/d) over a 14 days period. On the morning after the osmotic mini pump reservoirs liquid content should have been consumed mice were dissected to remove the peri-gonadal epididymal fat pad for white adipose tissue gene expression analysis. At least 220 mg of white adipose tissue was quickly removed, shock-frozen in liquid nitrogen and thereafter stored at -80C for mRNA extraction. To perform RNA-Seq analysis, samples were single-end sequenced at a depth of 75 80M reads per sample with a read-length of 51 bp using an Illumina Hiseq2500. Raw sequencing files were quality controlled with FastQC. Alignment and trimming of reads was performed using the OSA algorithm against the mouse reference genome b38.1 with RefSeq as the gene model as implemented in OmicSoft ArraySuite software, version 8. RNA transcripts were quantified using RSEM methods as implemented in Arraystudio counting count the read fragments mapping to each individual gene and quantify expression by the corresponding FPKM. In summary, expression was measured as FPKM for 25,054 unique genes. Principal component analysis was then performed to check for possible batch effects and outliers complemented by calculating the RNA-Seq 5'->3' trend for each sample. One sample for the vehicle control as well as for the Liraglutide group were identified as outliers and removed from subsequent analysis, resulting in 7 and 8 samples remaining for each group respectively. Abundance values (counts) were normalized and compared between liraglutide treated mice versus baseline controls using DESeq2. All P-values were adjusted for multiple testing by the Benjamini-Hochberg method.

Project description:Recent studies indicate that glucagon-like peptide (GLP)-1 inhibits appetite in part through regulation of soluble leptin receptors. Thus, during weight loss maintenance, GLP-1 receptor agonist (GLP-1RA) administration may inhibit weight loss-induced increases in soluble leptin receptors thereby preserving free leptin levels and preventing weight regain.In a randomized controlled trial, 52 healthy obese individuals were, after a diet-induced 12% body weight loss, randomized to treatment with or without administration of the GLP-1RA liraglutide (1.2?mg per day). In case of weight gain, low-calorie diet products were allowed to replace up to two meals per day to achieve equal weight maintenance. Glucose tolerance and hormone responses were investigated before and after weight loss and after 52 weeks weight maintenance. Primary end points: increase in soluble leptin receptor plasma levels and decrease in free leptin index after 52 weeks weight loss maintenance.Soluble leptin receptor increase was 59% lower; 2.1±0.7 vs 5.1±0.8?ng?ml(-1) (-3.0 (95% confidence interval (CI)=-0.5 to -5.5)), P<0.001 and free leptin index decrease was 43% smaller; -62±15 vs -109±20 (-47 (95% CI=-11 to -83)), P<0.05 with administration of GLP-1RA compared with control group. The 12% weight loss was successfully maintained in both the groups with no significant change in weight after 52 weeks follow-up. The GLP-1RA group had greater weight loss during the weight maintenance period (-2.3?kg (95% CI=-0.6 to -4.0)), and had fewer meal replacements per day compared with the control group (minus one meal per day (95% CI=-0.6 to -1)), P<0.001. Fasting glucose was decreased by an additional -0.2±0.1?mmol?l(-1) in the GLP-1RA group in contrast to the control group, where glucose increased 0.3±0.1?mmol?l(-1) to the level before weight loss (-0.5mmol?l(-1) (95% CI=-0.1 to -0.9)), P<0.005. Meal response of peptide PYY3-36 was higher at week 52 in the GLP-1RA group compared with the control group, P<0.05.The weight maintaining effect of GLP-1RAs may be mediated by smaller decrease in free leptin and higher PYY3-36 response. Low dose GLP-1RA therapy maintained 12% weight loss for 1 year and may prevent pre-diabetes in obesity.

Project description:Having demonstrated short-term weight loss with liraglutide in this group of obese adults, we now evaluate safety/tolerability (primary outcome) and long-term efficacy for sustaining weight loss (secondary outcome) over 2 years.A randomized, double-blind, placebo-controlled 20-week study with 2-year extension (sponsor unblinded at 20 weeks, participants/investigators at 1 year) in 19 European clinical research centers.A total of 564 adults (n=90-98 per group; body mass index 30-40?kg?m(-2)) enrolled, 398 entered the extension and 268 completed the 2-year trial. Participants received diet (500?kcal?deficit per day) and exercise counseling during 2-week run-in, before being randomly assigned (with a telephone or web-based system) to once-daily subcutaneous liraglutide (1.2, 1.8, 2.4 or 3.0?mg, n=90-95), placebo (n=98) or open-label orlistat (120?mg × 3, n=95). After 1 year, liraglutide/placebo recipients switched to liraglutide 2.4?mg, then 3.0?mg (based on 20-week and 1-year results, respectively). The trial ran from January 2007-April 2009 and is registered with Clinicaltrials.gov, number NCT00480909.From randomization to year 1, liraglutide 3.0?mg recipients lost 5.8?kg (95% confidence interval 3.7-8.0) more weight than those on placebo and 3.8?kg (1.6-6.0) more than those on orlistat (P?0.0001; intention-to-treat, last-observation-carried-forward). At year 2, participants on liraglutide 2.4/3.0?mg for the full 2 years (pooled group, n=184) lost 3.0?kg (1.3-4.7) more weight than those on orlistat (n=95; P<0.001). Completers on liraglutide 2.4/3.0?mg (n=92) maintained a 2-year weight loss of 7.8?kg from screening. With liraglutide 3.0?mg, 20-week body fat decreased by 15.4% and lean tissue by 2.0%. The most frequent drug-related side effects were mild to moderate, transient nausea and vomiting. With liraglutide 2.4/3.0?mg, the 2-year prevalence of prediabetes and metabolic syndrome decreased by 52 and 59%, with improvements in blood pressure and lipids.Liraglutide is well tolerated, sustains weight loss over 2 years and improves cardiovascular risk factors.

Dataset Information

The arcuate nucleus mediates GLP-1 receptor agonist liraglutide-dependent weight loss.

Publications

The arcuate nucleus mediates GLP-1 receptor agonist liraglutide-dependent weight loss.

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