Lysophosphatidic acid and sphingosine-1-phosphate are apical polarity cues in multiple organoid systems

Apicobasal polarization is crucial for tissue organization during in vivo development and in human organoid models. Extracellular matrix (ECM) signaling typically provides a basal cue, and intestinal and lung organoids reverse polarity from apical-in to apical-out after ECM removal. However, ECM-free brain organoids maintain apical-in polarity, suggesting that media components may influence polarity. Exposing brain organoids to serum induced apical-out orientation. Lysophosphatidic acid (LPA), present in the medium of prior apical-out techniques, was identified as the causative factor. LPA-induced apical-out orientation in brain organoids occurred within 1 day, lasted at least 1 month, and was optimal at human cerebrospinal fluid LPA concentrations. Sphingosine-1-phosphate (S1P) induced similar apical-out polarization. Pharmacological studies revealed that LPA/S1P act via a G-protein coupled receptor/RhoA pathway. Finally, LPA induced apical-out polarity in patient-derived human lung and intestinal organoids, iPSC spheres, and multilineage iPSC-derived intestinal organoids. These findings indicate that LPA signaling is a critical apical polarity cue in multiple tissues.