Autotaxin (ATX) is a secreted enzyme with lysophospholipase D (lysoPLD) activity, which converts lysophosphatidylcholine(LPC) into lysophosphatidic acid (LPA), a bioactive phospholipid involved ill numerous biological activities, including cell proliferation, differentiation, and migration. In the present study, we found that bacterial lipopolysaccharide(LPS), a well-known initiator of the inflammatory response, induced ATX expression in monocytic THP-1 cells. The activation of PKR, JNK, and p38 MAPK was required for the ATX induction. The LPS-induced ATX ill THP-1 cells was characterized as the beta isoform. In the presence of LPC, ATX could promote the migrations of THP-1 and Jurkat cells, which was inhibited by pertussis toxin (PTX), an inhibitor of Gi-mediated LPA receptor signaling, In summary, LPS induces ATX expression ill THP-1 cells via a PKR, JNK and p38 MAPK-mediated mechanism, and the ATX induction is likely to enhance immune cell migration in proinflammatory response by regulating LPA levels in the microenvironment. (C) 2008 Elsevier Inc. All rights reserved.