Terpene-Based Thiazole Hydrazines as Negative Allosteric Modulators of MRGPRX4: In Vitro Evaluation and Binding Site Analysis
Bibliographic record
Abstract
The human MAS-related G-protein-coupled receptors (MRGPRs) represent a promising therapeutic target for managing chronic itch and pain. Among them, MRGPRX4 is activated by bile acids in dorsal root ganglia (DRG) neurons and contributes to the cholestatic itch. Here, we report the design, synthesis, and in vitro evaluation of a focused library of functionalized terpene-based thiazole hydrazines targeting MRGPRX receptors. Functional assays identified two compounds, 1C and 3G, as negative allosteric modulators (NAMs) of MRGPRX4 with IC 50 values of 337 nM and 15.5 μM, respectively, and showed weak activity at MRGPRX2. Computational analysis suggested a putative NAM binding site adjacent to the orthosteric pocket involving key interactions with residues H92 3.22, K96 3.26, and R159 4.62 . The resulting site overlaps with the receptor activity-modifying protein 2 (RAMP2) interaction region, where RAMP2 antagonizes MRGPRX4 as a NAM. These findings provide a foundation for developing selective MRGPRX4 NAMs as novel therapeutic agents for chronic itch and pain.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".