Abstract 98: Embryonic Extracellular Matrix and Cell Fate Determination

Background - The determination of cell fate during development is governed by intrinsic factors, but also by interaction with the milieu in which they reside. The extracellular matrix (ECM) from rapidly developing tissue should form a rich signaling environment for cellular proliferation and differentiation. Hypothesis - Murine embryonic ECM can be prepared by detergent decellularization that is morphologically preserved, biocompatible for cell culture, and at E13.5 substantial enough to permit vascular catheterization and recellularization by perfusion. Methods and Results - To test the contribution of embryonic extracellular matrix (ECM) to the determination of cell fate, we undertook isolation of ECM from developing murine embryos. Triton X-100 and SDS detergent decellularization were used to isolate ECM from E10.5 and E13.5 embryos. Acellularity was confirmed by pico-green DNA assay (98.7 % ± 0.95 of DNA removed compared to control), as well as the lack of visible nuclei by H & E and DAPI histology. The matrix scaffolds were washed thoroughly with PBS and culture media to return them to a biocompatible state. Murine embryonic stem cells (mESC) modified to express EGFP were cultured on the exterior or the interior of the ECM scaffolds. mESCs seeded on the exterior of the E10.5 scaffolds or perfused through the E13.5 umbilical vasculature were highly adherent and proliferative during the 17 day culture period as evidenced by fluorescent microscopy. Perfused mESCs exhibited engrafted in the heart, liver, and vascular conduit E13.5 matrix 2 days post-infusion. Histology confirmed the attachment and morphologic alteration of the cultured cells on the exterior of the E10.5 ECM and presence of the perfused cells in the E13.5 embryo matrix interior. Conclusion - Biocompatible, acellular morphologically preserved embryonic ECM can be extracted from E10.5 and E13.5 murine embryos. By E13.5 the structural integrity of the acellular matrix can sustain vascular perfusion for delivery of mESCs to internal organoid structures. These ECM preparations support the proliferation and maintenance of mESCs externally and internally.