Leukotriene B 4receptors

Abstract

Leukotriene B 4 (LTB 4) is a classical pro-inflammatory lipid mediator that activates and recruits neutrophils into inflammatory areas. LTB 4 is an arachidonic acid-derived metabolite produced by 5-lipoxygenase and LTA 4 hydrolase. To date, two leukotriene B 4 receptors, the high-affinity receptor BLT1 and the low-affinity receptor BLT2, have been cloned, and a systemic knockout mouse for each receptor has been generated. BLT1 is mainly expressed in leukocytes, but BLT2 is expressed in epithelial cells. Based on many knockout mouse studies, BLT1 is now known to play important roles in acute and chronic inflammation and immune diseases. On the other hand, BLT2 protects against colitis, accelerates epidermal wound healing, and promotes cancer progression. Thus, BLT1 and BLT2 have totally different features with respect to their expression patterns and their physiological and pathological roles. In this review, we summarize the fundamental characteristics of BLT1 and BLT2, as well as recent advances in our understanding of the biosynthesis and degradation of LTB 4 and theLTB 4 receptors.