There is an urgent need for effective treatments targeting comorbidities of type 2 diabetes (T2DM) and obesity. Developing dual agonists of glucagon-like peptide 1 receptor (GLP-1R) and neuropeptide Y receptor type 2 (NPY2R) with combined PYY3-36 and GLP-1 bioactivity is promising. However, designing such dual agonists that effectively control glycemia and reduce weight while minimizing gastrointestinal side effects is challenging. In this study, we systematically evaluated the side effects induced by co-administering various GLP-1R agonists and PYY3-36 analogue. Our findings revealed that different GLP-1R agonist-PYY analogue combinations elicited gastrointestinal side effects of varying intensities. Among these, the co-administration of bullfrog GLP-1 analogue (bGLP-1) with PYY3-36 analogue resulted in lower gastrointestinal side effects. Thus, bGLP-1 was selected as the preferred candidate for designing dual GLP-1R/NPY2R agonists. Through stepwise structural design, optimization of linker arms, and durability enhancements, coupled with in vitro receptor screening, the novel peptide bGLP/PYY-19 emerged as the lead candidate. Notably, experimental results in mice and rats showed a significant reduction in emesis with bGLP/PYY-19 compared to semaglutide and bGLP-1 long-acting analogue (LAbGLP-1). Furthermore, bGLP/PYY-19 significantly outperformed semaglutide and LAbGLP-1 in reducing body weight in diet-induced obese (DIO) mice, without inducing nausea-associated behavior. These findings underscore the potential of dual-targeting single peptide conjugates as a promising strategy for developing glucoregulatory treatments that offer superior weight loss benefits and are better tolerated compared to treatments targeting GLP-1R alone.
