Apicobasal polarization is fundamental to tissue organization, yet traditional epithelial organoid models often form
"apical-in" cysts, where the functional apical surface is buried within a central lumen. This configuration creates a significant barrier for researchers, as the critical sites for nutrient absorption, cilia motility, and host-pathogen interactions are sequestered in an inaccessible "black box." We present a breakthrough in controlling tissue architecture by identifying lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P)—lipids found in biological fluids like serum and cerebrospinal fluid—as universal apical polarity cues.

We demonstrate that these phospholipids act via a GPCR/RhoA signaling pathway to induce apical-out orientation within 24 hours across diverse lineages, including brain, lung, and intestinal organoids. This "inside-out" flip moves the functional domain to the external surface, enabling transformative imaging and functional opportunities.

Externalizing the apical surface allows for high-resolution confocal Z-series of the bottom 100 μm without destructive cryosectioning. Researchers can utilize 60x objectives to map tight junction networks (ZO1), primary cilia (Arl13B), and microtubule organization directly at the organoid-media interface. This orientation is maintained for over one month, facilitating longitudinal studies of barrier function and morphology. Additionally, this method enables ECM-free culture, significantly reducing the costs and labor associated with traditional hydrogel removal.

By unlocking the hidden apical surface, this research provides the imaging community with a versatile, high-efficiency platform to study protein localization and disease mechanisms with unprecedented clarity.

If you are unable to attend the live event, please register and we will email you the recording.

Learning Objectives

Attendees of this webinar will learn:

1. LPA and S1P as universal polarity switches: These phospholipids in serum and CSF reverse organoid orientation within 24 hours via GPCR/RhoA signaling, externalizing the apical surface across brain, lung, and intestinal tissues.

2. High-resolution subcellular imaging: Apical-out organoids enable 60x whole-mount confocal imaging of tight junctions, primary cilia, and microtubules without cryosectioning.

3. Long-term experimental stability: Reversed polarity persists for over one month, supporting extended longitudinal studies of barrier function and morphology.

4. Streamlined, cost-effective workflow: This ECM-free approach eliminates expensive hydrogels and labor-intensive processing while providing a versatile platform for disease modeling.