Free fatty acid receptor 2 (FFA2) is expressed on enteroendocrine L cells that release glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) when activated by shortchain fatty acids (SCFAs). Functionally GLP-1 and PYY inhibit gut transit, increase glucose tolerance, and suppress appetite; thus, FFA2 has therapeutic potential for type 2 diabetes and obesity. However, FFA2-selective agonists have not been characterized in vivo. Compound 1 (Cpd 1), a potent FFA2 agonist, was tested for its activity on the following: GLP-1 release, modulation of intestinal mucosal ion transport and transit in wild-type (WT) and FFA2 2/2 tissue, and food intake and glucose tolerance in lean and diet-induced obese (DIO) mice. Cpd 1 stimulated GLP-1 secretion in vivo, but this effect was only detected with dipeptidyl peptidase IV inhibition, while mucosal responses were PYY, not GLP-1, mediated. Gut transit was faster in FFA2 2/2 mice, while Cpd 1 slowed WT transit and reduced food intake and body weight in DIO mice. Cpd 1 decreased glucose tolerance and suppressed plasma insulin in lean and DIO mice, despite FFA2 2/2 mice displaying impaired glucose tolerance. These results suggest that FFA2 inhibits intestinal functions and suppresses food intake via PYY pathways, with limited GLP-1 contribution. Thus, FFA2 may be an effective therapeutic target for obesity but not for type 2 diabetes.

Background and purpose: Glucokinase (GK) is the rate-limiting enzyme of hepatic glucose metabolism and acts as a sensor for glucose-stimulated insulin release in b-cells. Here we examine whether the lowering of blood glucose levels in the rat by small molecule glucokinase activators (GKAs) can be predicted from in vitro enzyme potencies and plasma compound exposure. Experimental approach: We developed an insulin resistant and hyperinsulinemic animal model, the high fat fed female Zucker (fa/fa) rat (HFFZ), and measured the acute in vivo glucose-lowering efficacy of a number of GKAs in an oral glucose tolerance test. Key results: Four GKAs (at 1 to 30 mg kg À1 ), with different in vitro enzyme potencies, dose-dependently improved oral glucose tolerance in HFFZ rats (10-40% decrease glucose area under the curve (AUC) from vehicle control). The extent of glucose lowering, or the pharmacodynamic (PD) effect, of a GKA was directly related to the total compound concentration in the plasma; the pharmacokinetic (PK) measurement. This PK-PD relationship was extended across a series of GKAs by accounting for differences in protein binding and in the in vitro potency. Conclusions and implications: When the unbound GKA compound level is greater than the in vitro enzyme potency there was significant blood glucose lowering in vivo. This latter relationship was upheld in non-diabetic Wistar rats orally dosed with a GKA. The robust and predictive nature of the PK-PD relationship for GKAs may prove of value in testing these agents in early human clinical studies.

A pyrazolo-pyrimidinone based series of growth hormone secretagogue receptor type 1a (GHS-R1a) antagonists and inverse agonists were identified using a scaffold hop from known quinazolinone GHS-R1a modulators. Lipophilicity was reduced to decrease hERG activity while maintaining GHS-R1a affinity.SAR exploration of a piperidine substituent was used to identify small cyclic groups as a functional switch from partial agonists to neutral antagonists and inverse agonists. A tool compound was identified which had good overall properties and sufficient oral plasma and CNS exposure to demonstrate reduced food intake in mice through a mechanism involving GHS-R1a.

BACKGROUND AND PURPOSEThe global heterozygous glucokinase (GK) knockout (gk wt/del ) male mouse, fed on a high-fat (60% by energy) diet, has provided a robust and reproducible model of hyperglycaemia. This model could be highly relevant to some facets of human type 2 diabetes (T2D). We aimed to investigate the ability of standard therapeutic agents to lower blood glucose at translational doses, and to explore the glucose-lowering potential of novel glucokinase activators (GKAs) in this model. EXPERIMENTAL APPROACHWe measured the ability of insulin, metformin, glipizide, exendin-4 and sitagliptin, after acute or repeat dose administration, to lower free-feeding glucose levels in gk wt/del mice. Further, we measured the ability of novel GKAs, GKA23, GKA71 and AZD6370 to control glucose either alone or in combination with some standard agents. KEY RESULTSA single dose of insulin (1 unit·kg ), AZD6370 also lowered basal levels of glucose without inducing hypoglycaemia. CONCLUSION AND IMPLICATIONSStandard glucose-lowering therapeutic agents demonstrated significant acute glucose lowering in male gk wt/del mice at doses corresponding to therapeutic free drug levels in man, suggesting the potential of these mice as a translatable model of human T2D. Novel GKAs also lowered glucose in this mouse model.

Sporadic Alzheimer’s disease (sAD) represents a serious and growing worldwide economic and healthcare burden. Almost 95% of current AD patients are associated with sAD as opposed to patients presenting with well-characterized genetic mutations that lead to AD predisposition, i.e., familial AD (fAD). Presently, the use of transgenic (Tg) animals overexpressing human versions of these causative fAD genes represents the dominant research model for AD therapeutic development. As significant differences in etiology exist between sAD and fAD, it is perhaps more appropriate to develop novel, more sAD-reminiscent experimental models that would expedite the discovery of effective therapies for the majority of AD patients. Here we present the oDGal mouse model, a novel model of sAD that displays a range of AD-like pathologies as well as multiple cognitive deficits reminiscent of AD symptomology. Hippocampal cognitive impairment and pathology were delayed with N-acetyl-cysteine (NaC) treatment, which strongly suggests that reactive oxygen species (ROS) are the drivers of downstream pathologies such as elevated amyloid beta and hyperphosphorylated tau. These features demonstrate a desired pathophenotype that distinguishes our model from current transgenic rodent AD models. A preclinical model that presents a phenotype of non-genetic AD-like pathologies and cognitive deficits would benefit the sAD field, particularly when translating therapeutics from the preclinical to the clinical phase.