Comparison of gene expression between mandibular and iliac bone-derived cells.

OBJECTIVES

The purpose of this study is to investigate the differences in gene expression between the human mandibular and iliac bone-derived cells (BCs) for better understanding of the site-specific characteristics of bones.

METHODS

Primary cells were obtained from mandibular and iliac bones from six healthy, elderly donors. To investigate site-specific differences, gene expression profile of mandibular and iliac BC from the same donors were compared via cDNA microarray analysis.

RESULTS

A comparison of the gene expression profiles revealed that 82 genes were significantly upregulated and 66 genes were downregulated with 1.5 fold or greater in mandibular versus iliac BCs. The most significantly differentially regulated genes were associated with skeletal system development or morphogenesis (SIX1, MSX1, MSX2, HAND2, PRRX1, OSR2, HOX gene family, PITX2). Especially, upregulated genes in mandibular BC were related with tooth morphogenesis, originated from the ectomesenchyme. Microarray analysis revealed that Msx1 was 2.03-fold and Msx2 was 1.99-fold upregulated in mandibular versus iliac BCs (both p < 0.01). Furthermore, in mandibular BCs, all members of the HOX gene family that were analyzed were downregulated (p < 0.01) and osteopontin was also downregulated by 2.84-fold (p < 0.01).

CONCLUSIONS

Site-specific differences between jaw and long bones can be explained by the differences in gene expression patterns. Our results suggest that bone cell-derived cells maintain the genetic characteristics of their embryological origin.

CLINICAL RELEVANCE: This study revealed fundamental differences in gene expression between the mandibular and iliac bone in humans. These differences could be important for understanding jaw bone-specific development of bisphosphonate-related osteonecrosis of the jaw.