Altered desensitization and internalization patterns of rodent versus human glucose‐dependent insulinotropic polypeptide (GIP) receptors. An important drug discovery challenge
Bibliographic record
Abstract
Abstract Background and Purpose The gut hormone glucose‐dependent insulinotropic polypeptide (GIP) signals via the GIP receptor (GIPR), resulting in postprandial potentiation of glucose‐stimulated insulin secretion. The translation of results from rodent studies to human studies has been challenged by the unexpected effects of GIPR‐targeting compounds. We, therefore, investigated the variation between species, focusing on GIPR desensitization and the role of the receptor C‐terminus. Experimental Approach The GIPR from humans, mice, rats, pigs, dogs and cats was studied in vitro for cognate ligand affinity, G protein activation (cAMP accumulation), recruitment of beta‐arrestin and internalization. Variants of the mouse, rat and human GIPRs with swapped C‐terminal tails were studied in parallel. Key Results The human GIPR is more prone to internalization than rodent GIPRs. Despite similar agonist affinities and potencies for G αs activation, especially, the mouse GIPR shows reduced receptor desensitization, internalization and beta‐arrestin recruitment. Using an enzyme‐stabilized, long‐acting GIP analogue, the species differences were even more pronounced. ‘Tail‐swapped’ human, rat and mouse GIPRs were all fully functional in their G αs coupling, and the mouse GIPR regained internalization and beta‐arrestin 2 recruitment properties with the human tail. The human GIPR lost the ability to recruit beta‐arrestin 2 when its own C‐terminus was replaced by the rat or mouse tail. Conclusions and Implications Desensitization of the human GIPR is dependent on the C‐terminal tail. The species‐dependent functionality of the C‐terminal tail and the different species‐dependent internalization patterns, especially between human and mouse GIPRs, are important factors influencing the preclinical evaluation of GIPR‐targeting therapeutic compounds. LINKED ARTICLES This article is part of a themed issue Complexity of GPCR Modulation and Signaling (ERNST). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.14/issuetoc
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".