Überexpression von β1-Integrin in oralen Keratinozyten korreliert mit deren hohen Proliferationskapazität

Abstract

Large defects of the oral mucosa are still a major challenge in reconstructive surgery. For the development of oral mucosal grafts, successful enrichment of cells with a high proliferative potential is highly desirable. Therefore, the aim of this study was to separate two fractions of oral keratinocytes based on their affinity to collagen type IV. Oral keratinocytes were isolated from oral mucosa and separated into two fractions with different affinities to collagen type IV. Growth curves, Western blot analysis and immunohistochemical staining were used to detect differences between the two cell fractions. The cell fraction (RAC-IV) that adhered to collagen type IV within 20 min showed higher proliferative potential, significantly higher (P < 0.05) expression of integrin beta1 and fewer apoptotic cells. In particular, this fraction included small proliferating cells with the typical polygonal shape of oral keratinocytes, whereas the non-proliferating cells (RAC-IV-D) were irregularly shaped. Immunohistochemical staining showed only some apoptotic RAC-IV cells, whereas RAC-IV-D cells showed a significant increase of M30-positive cells. In addition, Western blotting revealed significantly higher (P < 0.05) expression of integrin beta1 in the RAC-IV fraction than in the RAC-IV-D fraction. Our results show that it is possible to enrich a fraction of highly proliferative oral keratinocytes by means of their high affinity to collagen type IV.