Serum‐dependent epithelial cell sheet shrinkage upon detachment from temperature‐responsive culture surfaces

Abstract

Primary oral mucosal epithelial cells show cell stratification similarly to those in vivo under the optimum culture conditions supplemented with serum. By temperature reduction, all the cells on temperature‐responsive surfaces are spontaneously detached as a single contiguous cell sheet since the surfaces change hydrophilic. We have utilized these cell sheets in regenerative medicine of cornea and esophagus. Interestingly, harvested cell sheets shrank to 50% of the original size. By utilizing porous membrane, stratified epithelium‐like cell sheets were also harvested even without serum. However, the harvested cell sheets didn't show any shrinkage, while cell proliferation and colony‐forming efficiency were the same with or without serum. In addition, cell adhesion on culture substrata was significantly weak under the serum‐free culture condition. Electron microscopy revealed that the basal surfaces of cell sheets cultured in the serum‐free condition had less minute processes participating in cell adhesion onto substrata. DNA array analyses showed some inflammatory‐related genes including MMP‐9, IL‐1α, IL‐1α receptor, and calpain 5 were significantly upregulated by serum. These findings would prompt the further investigations to understand underlying molecular mechanisms to achieve reproducible, safe, and effective clinical applications of epithelial cell sheets.Grant Funding SourceGrant‐in‐Aid for Scientific Research