Bradykinin GPCR Assays
Background of Bradykinin
Bradykinin belongs to a family of small peptides binding to G protein-coupled receptors B1 and B2. Bradykinin plays an essential role in the regulation of pain and acts as a pro-inflammatory factor that leads to vasodilation, plasma protein extravasation, and smooth muscle contraction. Keeping a high level of bradykinin could be used for the treatment of hypertension and heart failure.
Fig.1. Mechanism involving bradykinin receptors and NF-κB signaling pathway. (Yang, 2018)
Distribution and Function of Bradykinin Receptors
Bradykinin receptors B1 and B2 are G protein-coupled receptors primarily expressed in the heart, central nervous system, kidney, skeletal muscle, gastrointestinal tract, and other tissues. B2 is expressed relatively at a higher level compared to B1, especially on vascular endothelial cells. However, the B1 level will be upregulated under the stimulation of inflammatory factors in response to pathophysiologic processes, including lipopolysaccharide, endotoxins, and cytokines, as well as diabetes and ischemia-reperfusion injury. The combination of B1 receptors and bradykinins promotes the cytosolic calcium ion concentration, and thus causes inflammations.
Subtypes and Mechanisms of Bradykinin Receptors
The family of bradykinin receptor contains B1 and B2 receptors. B1 receptors stimulate signal transduction through coupling the Gi/Go family and Gq/G11 family, while B2 receptors also couple Gs proteins stimulating adenylyl cyclase.
| Receptor | Gene | Mechanism | Agonists | Antagonists |
| B1 receptor | BDKRB1 |
|
|
|
| B2 receptor | BDKRB2 |
|
|
|
Assay List of Bradykinin Receptors
Creative Biolabs can provide a range of assays of bradykinin receptors. You can choose the assay in the list or contact us for more information:
Published Data
| Paper Title | In Vitro Pharmacological Profile of a New Small Molecule Bradykinin B2 Receptor Antagonist |
| Journal | Frontiers in Pharmacology |
| Published | 2020 |
| Abstract | The study has reported the discovery and early characterization of the B2 receptor antagonist, Compound 3. They used a calcium mobilization assay to demonstrate the antagonistic effects of different Compounds. In addition, human isolated umbilical vein bioassay was applied. They applied compound 3 on different species to test its selectivity on B2 receptors of different species. In vitro off-target profiling of compound 3 was used to check the degree of selectivity on different GPCRs. In addition, microsomal stability assay and Caco-2 permeability assay were applied. Compound 3 has been a crucial first step in the search for the orally bioavailable B2 receptor antagonist. |
| Result |
The results of the calcium mobilization assay showed that Compound 3 was a highly potent antagonist of human recombinant B2 receptor similar to Compound 1 and Compound 2 (Kb values 0.24, 0.95, and 1.24 nM, respectively). Compound 3 has been indicated to be more potent than prior art compounds and icatibant (Kb value 2.81 nM). The antagonistic compound showed potent suppressive capability on BK-induced contraction of endogenous B2 receptor using human isolated umbilical vein bioassay. The result indicated that Compound 3 suppresses the BK-induced c-Fos signaling and internalization of B2 receptors in HEK293 cells, while it did not have the antagonistic effect on the bradykinin B1 receptor. Compound 3 showed different antagonist potency at B2 receptors of different species, including cynomolgus monkey, dog, rat, and mouse. Compound 3 had a high degree of selectivity over a wide range of molecular targets, including the bradykinin B1 receptor. The result of the microsomal stability assay demonstrated a lower intrinsic clearance of Compound 3. Compound 3 was predicted to be not a substrate of efflux pumps and may have good oral bioavailability.
|
Fig.2. Specificity of the antagonist effect of Compound 3 or icatibant. (Lesage, 2020)
References
- Yang, L.; et al. Bradykinin receptor in immune-mediated renal tubular injury in trichloroethylene-sensitized mice: Impact on NF-κB signaling pathway. Journal of Immunotoxicology. 2018, 15(1): 126-136.
- Lesage, A.; et al. In Vitro pharmacological profile of a new small molecule bradykinin B2 receptor antagonist. Frontiers in Pharmacology. 2020, 11: 916.
