11 research outputs found
Regulation of resveratrol Oâmethyltransferase gene in pterostilbene defensing the sour rot of wine grape
Role of myeloperoxidase in the regulated cell death of polymorphonuclear neutrophils undergoing oxidative burst
The histamine H4 receptor is a potent inhibitor of adhesion-dependent degranulation in human neutrophils
The histamine H4 receptor regulates the inflammatory response. However, it is not known whether this receptor has a functional role in human neutrophils. We found that fMLP (1 ÎŒM), but not histamine (0.1â1 ÎŒM), induced Mac-1-dependent adhesion, polarization, and degranulation (release of lactoferrin). A pretreatment of neutrophils with histamine (0.001â1 ÎŒM) or JNJ 28610244 (0.1â10 ÎŒM), a specific H4 receptor agonist, led to inhibition of degranulation. Total inhibition of degranulation was obtained with 0.1 ÎŒM histamine and 10 ÎŒM JNJ 28610244. Furthermore, such inhibition by histamine of degranulation was reversed by JNJ 7777120 and JNJ 28307474, two selective H4 receptor antagonists. However, neither histamine nor the H4 receptor agonist JNJ 28610244 prevented fMLP-induced, Mac-1-dependent adhesion, indicating that the H4 receptor may block signals emanating from Mac-1-controlling degranulation. Likewise, engagement of the H4 receptor by the selective agonist JNJ 28610244 blocked Mac-1-dependent activation of p38 MAPK, the kinase that controls neutrophil degranulation. We also show expression of the H4 receptor at the mRNA level in ultrapure human neutrophils and myeloid leukemia PLB-985 cells. We concluded that engagement of this receptor by selective H4 receptor agonists may represent a good, therapeutic approach to accelerate resolution of inflammation