Third intracellular loop of glucagon like-peptide-1 receptor is coupled with endogenous mono-ADP-ribosyltransferase - novel type of receptor regulation?

Genetic variability in GLP-1 receptor is associated with inter-individual differences in weight lowering potential of liraglutide in obese women with PCOS: a pilot study

PURPOSE

The weight lowering potential of glucagon-like peptide 1 (GLP-1) receptor agonists (RAs) is inter-individually different and clinically unpredictable. The potential role of genetic variability of GLP-1R on body weight response to GLP-1 RAs in obese women with polycystic ovary syndrome (PCOS) has not yet been evaluated.

METHODS

Fifty-seven obese women with PCOS (aged 30.7 ± 7.0, BMI 38.6 ± 5.3 kg/m(2)) were assigned to liraglutide 1.2 mg QD s.c. for 12 weeks and classified as strong responders regarding weight loss if they lost 5% or more of their initial body weight. They were genotyped for common GLP-1R single nucleotide polymorphisms (SNPs) rs6923761 and rs10305420. Changes of measures of obesity were measured before and at the end of the treatment.

RESULTS

Twenty out of 57 subjects were strong responders and lost 7.38 ± 1.74 compared to 2.11 ± 2.17 kg lost in poor responders. Carriers of at least one polymorphic rs10305420 allele had poor treatment response compared to carriers of two wild type alleles (OR = 0.27, 95% CI = 0.09-0.85, P = 0.025). Carriers of at least one polymorphic rs6923761 allele tended to have stronger treatment response compared to carriers of two wild type alleles (OR = 3.06, 95% CI = 0.96-9.74, P = 0.058). Fasting glucose and glucose after oral glucose tolerance test (OGTT) comparably decreased in both groups when compared to baseline, whereas no within treatment differences were found in androgen profile. Gastrointestinal adverse events were transit and balanced between strong and poor responders.

CONCLUSIONS

GLP-1R rs10305420 polymorphism explained some of the inter-individual differences in response to liraglutide regarding weight loss in obese PCOS women.

A continued saga of Boc5, the first non-peptidic glucagon-like peptide-1 receptor agonist with in vivo activities

Glucagon-like peptide-1 (GLP-1)-based therapy presents a promising option for treating type 2 diabetes. However, there are several limitations relative to the peptidic GLP-1 mimetics currently on the market or under development. This concern has led to a continued interest in the search for non-peptidic agonists for GLP-1 receptor (GLP-1R). Here, we briefly review the discovery, characterization and current status of a novel class of cyclobutane-derivative-based non-peptidic agonists for GLP-1R, including Boc5 and its newly discovered analogue WB4-24. Although the oral bioavailability of such compounds still poses great challenges, the progress made so far encourages us to identify a truly 'druggable' small molecule agonist for GLP-1R.