Tag: FACS

Posted on

An Orally Bioavailable Small Molecule Antagonist of CRTH2, Ramatroban (BAYu3405), Inhibits Prostaglandin D2-Induced Eosinophil Migration in Vitro

Ramatroban (Baynas, BAY u3405), a thromboxane A2(TxA2) antagonist marketed for allergic rhinitis, has been shown to partially attenuate prostaglandin (PG)D2-induced bronchial hyperresponsiveness in humans, as well as reduce antigen-induced early- and late-phase inflammatory responses in mice, guinea pigs, and rats. PGD2 is known to induce eosinophilia following intranasal administration, and to induce eosinophil activation in vitro. In addition to the TxA2 receptor, PGD2 is known as a ligand for the PGD2receptor, and the newly identified G-protein-coupled chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). To fully characterize PGD2-mediated inflammatory responses relevant to eosinophil activation, further analysis of the mechanism of action of ramatroban has now been performed. PGD2-stimulated human eosinophil migration was shown to be mediated exclusively through activation of CRTH2, and surprisingly, these effects were completely inhibited by ramatroban. This is also the first report detailing an orally bioavailable small molecule CRTH2 antagonist. Our findings suggest that clinical efficacy of ramatroban may be in part mediated through its action on this Th2-, eosinophil-, and basophil-specific chemoattractant receptor.

http://jpet.aspetjournals.org/content/305/1/347.long

Posted on

Expression of Stromal-Derived Factor-1 Is Decreased by IL-1 and TNF and in Dermal Wound Healing

Stromal-derived factor-1 (SDF-1) is a CXC chemokine that is believed to be constitutively expressed by stromal cells of numerous tissues. In this report, we demonstrate that dermal fibroblasts and vessels of noninflamed tissues express SDF-1. Unexpectedly, we found that expression of SDF-1 is regulated by inflammation. Expression of SDF-1 by primary cultures of human gingival fibroblasts is potently inhibited by activated macrophages via secretion of IL-1α and TNF-α. Levels of SDF-1 mRNA also decrease in acutely inflamed mouse dermal wounds. We propose that SDF-1 functions as a homeostatic regulator of tissue remodeling, whose expression stabilizes existing dermal architecture.

http://www.jimmunol.org/content/166/9/5749.long

Posted on

Ramatroban (BAY u3405), Inhibits Prostaglandin D2-Induced Eosinophil Migration in Vitro

Ramatroban (Baynas, BAY u3405), a thromboxane A2(TxA2) antagonist marketed for allergic rhinitis, has been shown to partially attenuate prostaglandin (PG)D2-induced bronchial hyperresponsiveness in humans, as well as reduce antigen-induced early- and late-phase inflammatory responses in mice, guinea pigs, and rats. PGD2 is known to induce eosinophilia following intranasal administration, and to induce eosinophil activation in vitro. In addition to the TxA2 receptor, PGD2 is known as a ligand for the PGD2receptor, and the newly identified G-protein-coupled chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). To fully characterize PGD2-mediated inflammatory responses relevant to eosinophil activation, further analysis of the mechanism of action of ramatroban has now been performed. PGD2-stimulated human eosinophil migration was shown to be mediated exclusively through activation of CRTH2, and surprisingly, these effects were completely inhibited by ramatroban. This is also the first report detailing an orally bioavailable small molecule CRTH2 antagonist. Our findings suggest that clinical efficacy of ramatroban may be in part mediated through its action on this Th2-, eosinophil-, and basophil-specific chemoattractant receptor.

http://jpet.aspetjournals.org/content/305/1/347.full

Posted on

Chemotaxis Assay

The purpose of a chemotaxis assay is to determine whether your protein or small molecule of interest has chemotactic activity on a specific cell type. Chemotaxis is the ability of a protein to direct the migration of a specific cell. This assay is based on the premise of creating a gradient of the chemotactic agent and allowing cells to migrate through a membrane towards the chemotactic agent. If the agent is not chemotactic for the cell, then the majority of the cells will remain on the membrane. If the agent is chemotactic, then the cells will migrate through the membrane and settle on the bottom of the well of the chemotaxis plate.

labs.idi.harvard.edu/springer/uploads/Protocols/ChemotaxisAssay.pdf