GLP-2 Tirzepatide

GLP-2 Tirzepatide

• Peptide Partners Manufacturer ID: WF03
• Batch ID: TZ202605

Research Studies

(for educational purposes only)

Study 1: Tirzepatide is an imbalanced and biased dual GIP and GLP-1 receptor agonist

Authors: Willard FS, Douros JD, Showalter AD, Wainscott DB, Suter TM, Capozzi ME, Cardona GR, Urva S, Emmerson PJ, Rosenkilde MM, Campbell JE, Sloop KW

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC7526454/

Scientific Findings

Studies of the dual GIP and GLP-1 receptor agonist tirzepatide reveal occupancy favoring the GIP receptor and biased cAMP signaling at the GLP-1 receptor. Pharmacological characterization shows tirzepatide is an imbalanced agonist with full efficacy at GIPR but only partial efficacy at GLP-1R, exhibiting biased signaling that favors cAMP over β-arrestin recruitment. It differentially induces internalization of GIPR versus GLP-1R, with full internalization of GIPR but limited internalization of GLP-1R. Ex vivo experiments using pancreatic islets indicate that β-arrestin1 limits insulin response to GLP-1 but not GIP or tirzepatide, supporting a distinct signaling profile. The study also introduces receptor occupancy estimation methods, highlighting the pharmacological basis for tirzepatide's efficacy and suggesting that biased agonism and receptor engagement contribute to its metabolic benefits.

Plain English Interpretation

This research explains how tirzepatide works at the molecular level. It mainly activates the GIP receptor strongly but only partly activates the GLP-1 receptor, and it prefers certain signaling pathways over others. This unique activity may help explain why tirzepatide is effective in lowering blood sugar and reducing weight. It also shows that tirzepatide affects the receptors differently, internalizing GIP receptors fully but only partially affecting GLP-1 receptors. These findings help us understand how tirzepatide improves metabolic health and can guide the development of future treatments.

Study 2: Tirzepatide modulates the regulation of adipocyte nutrient metabolism through long-acting activation of the GIP receptor

Authors: Ajit Regmi, Eitaro Aihara, Michael E. Christe, Gabor Varga, Thomas P. Beyer, Xiaoping Ruan, Emily Beebe, Libbey S. O’Farrell, Melissa A. Bellinger, Aaron K. Austin, Yanzhu Lin, Haitao Hu, Debra L. Konkol, Samantha Wojnicki, Adrienne K. Holland, Jessica L. Friedrich, Robert A. Brown, Amanda S. Estelle, Hannah S. Badger, Gabriel S. Gaidosh, William Roell

Source: https://www.sciencedirect.com/science/article/pii/S1550413124001864

Scientific Findings

Using human adipocyte and mouse models, we investigated how long-acting GIPR agonists regulate fasted and fed adipocyte functions. In functional assays, GIPR agonism enhanced insulin signaling, augmented glucose uptake, and increased the conversion of glucose to glycerol in a cooperative manner with insulin; however, in the absence of insulin, GIPR agonists increased lipolysis. In diet-induced obese mice treated with a long-acting GIPR agonist, circulating triglyceride levels were reduced during oral lipid challenge, and lipoprotein-derived fatty acid uptake into adipose tissue was increased. Our findings support a model for long-acting GIPR agonists to modulate both fasted and fed adipose tissue function differentially by cooperating with insulin to augment glucose and lipid clearance in the fed state while enhancing lipid release when insulin levels are reduced in the fasted state.

Plain English Interpretation

This study shows that tirzepatide, a drug that activates GIP and GLP-1 receptors, can directly affect fat cells by increasing their ability to take up and store nutrients when insulin is present (fed state) and promoting fat breakdown when insulin is low (fasted state). These effects help improve blood sugar and lipid levels without increasing fat mass, offering a better understanding of how tirzepatide works to improve metabolic health in diabetes and obesity.

Study 3: GLP-1/GIP dual agonist tirzepatide normalizes diabetic nephropathy via PI3K/AKT mediated suppression of oxidative stress

Authors: Yan Tian, Ruixue Tian, He Juan, Yafan Guo, Pan Yan, Yao Cheng, Rongshan Li, Baodong Wang

Source: https://www.sciencedirect.com/science/article/pii/S1567576924023993

Scientific Findings

The study investigates the effects of the dual GLP-1/GIP receptor agonist tirzepatide on diabetic nephropathy (DN) in mice and in vitro podocyte cells. It demonstrates that tirzepatide reduces glucose levels, body weight, and urine albumin-to-creatinine ratio, and enhances antioxidative stress activities, similar to semaglutide, at a dose one-third lower. Transcriptome sequencing revealed that tirzepatide significantly enriches the PI3K-AKT signaling pathway, which was validated by Western blot and immunohistochemistry showing activation of this pathway. In vitro, tirzepatide regulated oxidative stress and the PI3K-AKT pathway in high glucose-exposed podocytes, with its antioxidative effects reversed by a PI3K inhibitor. These findings suggest tirzepatide mitigates DN by activating the PI3K/AKT pathway, reducing oxidative stress and podocyte injury, independent of its hypoglycemic effects.

Plain English Interpretation

This study shows that tirzepatide can protect kidneys from damage caused by diabetes. It works by activating a specific signaling pathway (PI3K/AKT) that helps reduce harmful oxidative stress in kidney cells. This protective effect was observed in both diabetic mice and in lab-grown kidney cells, and it works independently of tirzepatide's ability to lower blood sugar. This suggests that tirzepatide has direct protective effects on the kidneys, which could be beneficial for patients with diabetic kidney disease.