Doctoral Dissertation Improvement: Mechanobiology of Primate Cranial Sutures

Bone growth in the skull occurs at the perimeter of cranial bones in what are referred to as cranial sutures. Bone growth at suture margins is required to accommodate the growing brain. Sutures themselves are like ligaments that join the skull bones to one another, and the suture tissue itself must be strong in order to resist forces emanating from chewing muscles that attach to the bones of the skull. The central goal of this study is to better understand the basic mechanisms that regulate the growth and form of primate cranial sutures. Through the use of laboratory rodents, molecular aspects of cranial suture regulatory mechanisms will be perturbed. By observing the response of these systems, such as cranial suture remodeling, to various disruptions, a mechanistic explanation for how skeletal tissues grow and respond to mechanical influences can be ascertained. These results will be used to test hypotheses relating primate feeding behavior and encephalization to cranial suture morphology.

Understanding the mechanisms that determine how cranial sutures adapt and grow in response to mechanical forces has several broader impacts. For example, premature fusion of the cranial sutures (craniosynostosis) occurs in 1 in 1500 births. This premature fusion restricts brain development and usually requires invasive surgical intervention to 'release' the suture. Understanding how cells in the suture respond to changes in mechanical stress may eventually lead to novel, non-surgical therapies to treat craniosynostosis. Furthermore, the orthodontic and oral surgery communities will also benefit from an expanded understanding of how tissues of the skull respond to changes in mechanical stress. In addition to these medically oriented societal impacts, the research described here will impact our basic understanding of how diet and brain enlargement have shaped the skulls of humans and our primate relatives over time. This knowledge will in turn expand upon current strategies and approaches for investigating the evolutionary changes that have played significant roles in the origin of humankind.