An ATX-LPA(6)-Gα(13)-ROCK axis shapes and maintains caudal vein plexus in zebrafish

Lysophosphatidic acid (LPA) is a potential regulator of vascular formation derived from blood. In this study, we utilized zebrafish as a model organism to monitor the blood vessel formation in detail. Zebrafish mutant of ATX, an LPA-producing enzyme, had a defect in the caudal vein plexus (CVP). Pharmacological inhibition of ATX resulted in a fusion of the delicate vessels in the CVP to form large sac-like vessels. Mutant embryos of LPA(6) receptor and downstream Gα(13) showed the same phenotype. Administration of OMPT, a stable LPA-analog, induced rapid CVP constriction, which was attenuated significantly in the LPA(6) mutant. We also found that blood flow-induced CVP formation was dependent on ATX. The present study demonstrated that the ATX-LPA(6) axis acts cooperatively with blood flow and contributes to the formation and maintenance of the CVP by generating contractive force in endothelial cells.