CLONING AND CHARACTERIZATION OF RAT C3A RECEPTOR - DIFFERENTIAL EXPRESSION OF RAT C3A AND C5A RECEPTORS BY LPS STIMULATION

The anaphylatoxin C3a, generated during complement activation, is a fa ctor known to mediate various inflammatory reactions, The human C3a re ceptor (C3aR) was recently cloned and identified to be a member of the G-protein-coupled receptor family, C3aR is characterized by seven tra nsmembrane domains including a large second extracellular loop that ap pears to be a unique feature of this receptor, Here we report the isol ation of the rat C3aR clone and confirm that the isolated cDNA coded f or rat C3aR based on C3a binding analysis to stably transfected cells, Northern blot analysis of rat C3aR revealed expression in various tis sues, similar to that of human C3aR but dissimilar to rat C5aR, We fou nd that expression of rat C3aR in various tissues did not increase sig nificantly after LPS injection, whereas rat C5aR expression is greatly increased, These results suggest that expression of C3aR and C5aR is independently regulated in rat cells and tissues. (C) 1998 Academic Pr ess.