Bone Abstracts

Caspases are the basic enzymatic components in the apoptotic process. Recently, these molecules seem to participate not only in apoptotic but also in other cellular events, particularly in differentiation. This work aimed to further investigate novel roles of executive caspases such as caspase-7. The investigation is based on our previously published findings showing non-apoptotic roles of caspase-7 in odontogenesis.

In this study, we followed the localization of the activated form of caspase-7 during alveolar and mandibular bone formation and ossification in mice. As cleaved caspase-7 was present in number of cells that did not show signs of apoptosis, we approached the PCR array technology to examine osteogenic molecular networks in the WT vs caspase-7 deficient mice. Samples of the mandibular bone at the embryonic stage 15.5 were used. Mandibular bones fixed in RNALater were accurately cut off tissue slices. Examination of 84 genes was performed in the assay. Total mRNA was transcribed into cDNA and the Mouse Osteogenenic PCR array (SA Biosciences, PAM-026A-24) performed.

PCR array analysis of the mandibular bone of caspase-7 deficient vs WT mice showed a significant decrease in mRNA levels of several genes. One of them was Smad1, the key player in BMP pathway and induction of bone formation. Moreover, a decreasing trend but not a statistically significant drop was observed in other genes important in osteogenesis such as ameloblastin, BMPR1A, DMP1, FGF2, FGF2R or MMP8.

Caspase-7 apparently interacts with osteogenic signals during early mandibular bone development. Further investigations are under process to specify the participation of caspase-7 in intramembranous osteogenesis.

Supported by the Grant Agency of the Czech Republic: P302/12/J059 (at the IAPG) and P502/12/1285 (at the UVPS).