A mathematical model for mechanotransduction at the early steps of suture formation

Growth and patterning of craniofacial sutures are subjected to the effects of mechanical stress. Mechanotransduction processes occurring at the margins of the sutures are not precisely understood. Here, we propose a simple theoretical model based on the orientation of collagen fibres within the suture in response to local stress. We demonstrate that fibre alignment generates an instability leading to the emergence of interdigitations. We confirm the appearance of this instability both analytically and numerically. To support our model, we use histology and synchrotron x-ray microtomography and reveal the fine structure of fibres within the sutural mesenchyme and their insertion into the bone. Furthermore, using a mouse model with impaired mechanotransduction, we show that the architecture of sutures is disturbed when forces are not interpreted properly. Finally, by studying the structure of sutures in several gnathostomes, we show that bone deposition patterns during dermal bone growth are conserved within jawed vertebrates. In total, these results strongly support the role of mechanical constraints in the growth and patterning of craniofacial sutures, a process that was probably effective at the emergence of gnathostomes, and provide new directions for the understanding of normal and pathological suture fusion. 1 ha l-0 07 09 48 4, v er si on 1 17 M ay 2 01 3 Author manuscript, published in "Proceedings of the Royal Society of London. Series B, Containing papers of a Biological character. Royal Society (Great Britain) 280, 1759 (2013) 20122670" DOI : 10.1098/rspb.2012.2670