Hepatocyte Aggregation and Reorganization of EHS Matrix Gel

Abstract

The nature of the extracellular matrix profoundly influences the morphology and function of epithelial cells, such as hepatocytes, in tissue culture. For Engelbroth-Holm-Swarm (EHS) sarcoma-derived gels (e.g., Matrigel), rat hepatocytes exhibit limited spreading, and within 1–2 days they form spheroidal aggregates that progressively enlarge in culture. Using timelapse video microscopy and object-tracking analysis, we found that hepatocyte aggregation correlates directly with EHS matrix reorganization. Reorganization refers to the displacement of regions of the EHS matrix substrate through the activity of the cells. Our results indicate that both aggregates and isolated hepatocytes were able to create "zones of influence" within which they effectively reorganized their EHS matrix environment. Matrix reorganization and hepatocyte movement were significantly reduced either by altering the deformability of the matrix (via chemical cross-linking) with gluteraldehyde or by disrupting the actin cytoskeleton with cytochalasin D.