Autophagy Is Involved In The Premature Calvarial Ossification In Nonsyndromic Craniosynostosis

Background and ObjectiveNonsyndromic craniosynostosis(NSC)occurs when the main cranial defect is fused sutures,representing a paradigm of aberrant osteogenesis with an unclear multifactorial etiopathogenesis.Local osteoblast alterations at the margins of adjacent bones may lead to premature suture ossification.Autophagy is a critical process for bone health and development.Local abnormal autophagy could contribute to the pathogenesis of premature suture ossification occurring in NSC.The purpose of this study was to provide evidence for a direct role of autophagy in the calvarial ossification process and to investigate the possible role of autophagy in the molecular mechanisms underlying premature ossification.MethodsSuture tissues were taken from one prematurely fused suture and one unfused suture as a matched pair from each patient.The suture complex was dissected from all specimens and the overlying pericranium was removed and then suture cells were isolated and cultured.Osteogenic differentiation,mineralization,LC3-II and markers were analyzed.ResultsIn this study,we showed that autophagic activity exists in cranial suture mesenchymal stem cells and became more active in osteogenic differentiation conditions.Mineralization and LC3-II analyses showed that autophagy was activated in the pathological group during osteogenic differentiation,leading to more mineralized nodule formation.Treatment with 3-methyl adenine and rapamycin showed that autophagy activated by rapamycin led to increasing ossification,but inhibiting autophagy by 3-methyl adenine did not change the osteogenic result.ConclusionsOverall,autophagy plays an important role in ossification,and abnormal autophagy can lead to premature calvarial ossification in NSC.