Changes of gene expression of osteoblast cells stimulated by hydroxyapatite and hydroxyapatite composite by protein microarray – preliminary study

Abstract

The development of biomaterials for medical applications is an evolving subject in the area of human health care. Osteoconductive properties and biocompatibility of calcium phosphate ceramic materials such as hydroxyapatite (HAp) allow their use in skeletal tissue engineering. In order to overcome their limitations, such as brittleness, various composites have been developed so far. Combining different materials in composites generates better physiochemical properties of biomaterial. However, such a new mixture needs special attention in terms of its biocompatibility. Biomaterials used in bone repair, by nature of their in vivo applications, inevitably cause multi gene response of host organism. Gene microarray technology has been used successfully in bioengineering to characterize genes expression on mRNA level. The poor correlation between mRNA level and corresponding protein expression leads to the development of protein microarray.  Direct screening of the proteins level changes in cells responding to different biomaterials stimulation, permits evaluation of their biocompatibility. Our study has been conducted with osteoblast cell line stimulated by hydroxyapatite and hydroxyapatite/plant-derived polymer composite. The gene expression changes have been analyzed on the protein level with the use of The Panorama Ab Microarray Cell Signaling kit. The microarray tool for cellular-signaling protein has been chosen for noting the development of changes in signaling pathways with the use of pathway-finder software. In our studies, cells stimulated by HAp and HAp/plant-derived polymer composite showed no differences in the level of protein expression in almost 90%. Interestingly, the p53-controlled signaling pathways have not been changed by hydroxyapatite composite. Further analysis should be performed to identify the role of up- or down-regulated proteins in apoptosis and cell cycle pathways crucial for bioengineering applications.