title: Autotaxin/Lpar3 signaling regulates Kupffer's vesicle formation and left-right asymmetry in zebrafish.
abstract: Left-right (L-R) patterning is essential for proper organ morphogenesis and function. Calcium fluxes in dorsal forerunner cells (DFCs) are known to regulate the formation of Kupffer's vesicle (KV), a central organ for establishing L-R asymmetry in zebrafish. Here, we identify the lipid mediator lysophosphatidic acid (LPA) as a regulator of L-R asymmetry in zebrafish embryos. LPA is produced by Autotaxin (Atx), a secreted lysophospholipase D, and triggers various cellular responses through activation of specific G protein-coupled receptors (Lpar1-6). Knockdown of Atx or LPA receptor 3 (Lpar3) by morpholino oligonucleotides perturbed asymmetric gene expression in lateral plate mesoderm and disrupted organ L-R asymmetries, whereas overexpression of lpar3 partially rescued those defects in both atx and lpar3 morphants. Similar defects were observed in embryos treated with the Atx inhibitor HA130 and the Lpar1-3 inhibitor Ki16425. Knockdown of either Atx or Lpar3 impaired calcium fluxes in DFCs during mid-epiboly stage and compromised DFC cohesive migration, KV formation and ciliogenesis. Application of LPA to DFCs rescued the calcium signal and laterality defects in atx morphants. This LPA-dependent L-R asymmetry is mediated via Wnt signaling, as shown by the accumulation of β-catenin in nuclei at the dorsal side of both atx and lpar3 morphants. Our results suggest a major role for the Atx/Lpar3 signaling axis in regulating KV formation, ciliogenesis and L-R asymmetry via a Wnt-dependent pathway.
authors.affiliation: Institute of Zoology, National Taiwan University, 1 Roosevelt Road, Sec. 4, Taipei 10617, Taiwan,  Republic of China.
authors.forename: Shih-Lei
authors.initials: SL
authors.lastname: Lai
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Yao
authors.forename: Ku-Chi
authors.initials: KC
authors.lastname: Tsao
authors.forename: Anna J S
authors.initials: AJ
authors.lastname: Houben
authors.forename: Harald M H G
authors.initials: HM
authors.lastname: Albers
authors.forename: Huib
authors.initials: H
authors.lastname: Ovaa
authors.forename: Wouter H
authors.initials: WH
authors.lastname: Moolenaar
authors.forename: Shyh-Jye
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D020013:Calcium Signaling; D002467:Cell Nucleus / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D007555:Isoxazoles / Q000494:pharmacology; D008246:Lysophospholipids / Q000378:metabolism*; D009024:Morphogenesis; D060172:Morpholinos / Q000235:genetics / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism*; D011422:Propionates / Q000494:pharmacology; D049368:Receptors, Lysophosphatidic Acid / Q000235:genetics / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D060449:Wnt Signaling Pathway; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism; D000099189:Lysophospholipase D
chemical_list: D007555:Isoxazoles; D008246:Lysophospholipids; D060172:Morpholinos; D010727:Phosphoric Diester Hydrolases; D011422:Propionates; D049368:Receptors, Lysophosphatidic Acid; D018048:Receptors, Purinergic P2; D029961:Zebrafish Proteins; D051176:beta Catenin; D000099189:Lysophospholipase D; C477898:3-(4-(4-((1-(2-chlorophenyl)ethoxy)carbonyl amino)-3-methyl-5-isoxazolyl) benzylsulfanyl) propanoic acid; C032881:lysophosphatidic acid