The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)

Got a bone to pick? Functional implications of intracranial variation in osteoblast behavior


1Biological Sciences, Aerospace and Mechanical Engineering, and Anthropology, University of Notre Dame, 2Biological Sciences, University of Notre Dame, 3Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry

March 27, 2015 9:15, Grand Ballroom A/B Add to calendar

Non-sutural bone formation in the developing mammal skull is poorly understood, which limits progress understanding the function and evolution of the feeding apparatus and neurocranium. This is complicated by the fact that craniofacial osteoblasts vary with respect to embryological precursor (neural crest/paraxial mesoderm), ossification mode (intramembranous/endochondral) and peak load (high/low strain). Thus, identifying the mechanobiology of non-sutural osteoblasts from different skull locations has wide-ranging implications for improved characterization of regional variation in cranial development and functional determinants of morphological variation in living and fossil taxa.

The goals of this study are to: 1) develop a procedure for the isolation of non-sutural murine osteoblasts from the calvarium, basicranium and mandible; 2) evaluate the inherent osteogenic potential of isolated osteoblasts in 3D micromass culture; and 3) investigate if embryological origin affects osteoblast response to mechanical loading. To this end, osteoblasts were isolated from neonatal ICR mice via collagenase and outgrowth methods. Cultured osteoblasts displayed site-specific variation with respect to proliferation, alkaline phosphatase activity (a marker of bone formation) and biomineralization potential. Interestingly, equibiaxial tensile strain differentially affected expression patterns of calvarial osteoblasts arising from different embryological origins. Our research suggests that non-sutural cranial osteoblasts are not a homogeneous group of cells, but rather exhibit distinct behaviors depending on their anatomical location and embryological origin. Such novel findings are critically important for highlighting why bone should not be viewed as similar across skeletal regions with respect to its intrinsic growth potential or vis-a-vis extrinsic loading stimuli, an assumption inherent to most comparative studies.

Funding was provided by the University of Notre Dame and NIH Grant TL1TR001107 (A. Shekhar, PI) from the National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award.