GIPR-Ab/GLP-1 peptide–antibody conjugate requires brain GIPR and GLP-1R for additive weight loss in obese mice
Clarissa M. Liu, Elizabeth A. Killion, Rola Hammoud, Shu-Chen Lu, Renée Komorowski, Tongyu Liu, Matt Kanke, Veena A. Thomas, Kevin D. Cook, Glenn Sivits, Aerielle B Ben, Larissa Atangan, Rajaa Hussien, Amy Tang, Artem Shkumatov, Chi-Ming Li, Daniel J. Drucker, Murielle M. Véniant
Abstract
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 maximal weight loss in obese, primarily male, mice. Moreover, dulaglutide produces greater weight loss in CNS GIPR knockout (KO) mice, and the weight loss achieved with dulaglutide + GIPR-Ab is attenuated in CNS GIPR KO mice. Wild-type mice treated with GIPR-Ab/GLP-1 and CNS GIPR KO mice exhibit similar changes in gene expression related to tissue remodelling, 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 signalling are required for the full weight loss effect of a GIPR-Ab/GLP-1 peptide–antibody conjugate. This study, together with a companion manuscript, shows that in mice, weight loss as a result of GIP receptor antagonism requires and potentiates functional GLP-1 receptor signalling in the brain, explaining how both GIP receptor agonists and antagonists trigger weight loss through different mechanisms.