Mechanisms and rescue of craniosynostosis associated with gene-environment interaction

项目概要/摘要 颅缝早闭是一种颅面疾病，其特征是颅缝过早融合， 有缺陷的间充质干细胞（MSC）。严重的颅缝早闭患者通常有智力障碍， 残疾人（ID）。基因突变和环境因素都与颅缝早闭有关 再加上MSC耗竭。我们建议确定基因-环境相互作用机制， 通过解决颅缝早闭疾病基因Twist 1和Tcf 12如何与一个 环境风险因素，即母亲使用抗抑郁药西酞普兰。重要的是，我们的目标是 建立基于MSC的治疗策略，以减轻颅骨畸形和神经认知 颅缝早闭的功能障碍。这是创新和重要的，因为我们对 颅缝早闭症的环境因素和基因-环境相互作用，以及新的治疗方法 毁灭性的混乱是迫切需要的。神经认知功能的研究在很大程度上被忽视， 颅缝早闭症的动物模型，虽然认知异常，如ID已频繁 在颅缝早闭患者中观察到。目前唯一的治疗选择颅缝早闭是复杂的 手术，这是侵入性的，并且由于颅骨再次融合而经常需要再次手术。我们的MSC 基于颅缝再生的方法创伤小，避免了再融合，纠正了颅骨畸形， 在临床上恢复升高的颅内压，并减少晚年的神经认知功能障碍 相关的Twist 1 +/-小鼠颅缝早闭模型。在Twist 1 +/-小鼠和Twist 1 +/-小鼠中均观察到Gli 1 + MSC耗竭。 在母亲接触西酞普兰的患者中。西酞普兰是一种选择性5-羟色胺再摄取抑制剂（SSRI）， 这是最常用的抗抑郁药母亲SSRI的使用也被称为 人类颅缝早闭的环境危险因素。这些结果导致了一个假设，即Twist 1 和Tcf 12突变可能与西酞普兰相互作用，加剧颅骨和神经认知缺陷， 颅缝早闭，这将在目标1中进行测试。目标2将确定细胞和分子机制， 该基因突变和母体西酞普兰暴露共同作用导致颅缝早闭。目标3将使用 我们新开发的基于MSC的缝合再生方法，以确定MSC是否以及如何 植入减轻了由基因突变引起的颅缝早闭中的颅骨和神经认知功能障碍， 西酞普兰及其相互作用。总的来说，我们提出的研究建立在我们以前的发现基础上， 我们的研究结果将对提高对基因- 颅缝早闭的环境相互作用;它提供了一个独特的机会，改善治疗婴儿与 颅缝早闭

PROJECT SUMMARY / ABSTRACT Craniosynostosis is a craniofacial disorder characterized by the premature fusion of cranial sutures with defective mesenchymal stem cells (MSCs). Patients with severe craniosynostosis often have intellectual disabilities (IDs). Both genetic mutations and environmental factors have been linked to craniosynostosis coupled with MSC depletion. We propose to determine gene-environment interaction mechanisms in craniosynostosis by addressing how craniosynostosis disease genes Twist1 and Tcf12 interplay with an environmental risk factor, namely maternal usage of the antidepressant citalopram. Importantly, we aim to establish a MSC-based therapeutic strategy to mitigate both skull dysmorphology and neurocognitive dysfunctions in craniosynostosis. This is innovative and significant because we have little understanding of environmental factors and gene-environment interactions in craniosynostosis, and new treatments for this devastating disorder are urgently needed. Neurocognitive functions have been largely neglected in studies of animal models of craniosynostosis, although cognitive abnormalities such as IDs have been frequently observed in craniosynostosis patients. The only current treatment option for craniosynostosis is complex surgery, which is invasive and often requires re-operation due to the calvarial bones fusing again. Our MSC- based cranial suture regeneration approach is less invasive, avoids re-fusion, corrects skull dysmorphology, restores elevated intracranial pressure, and reduces neurocognitive dysfunctions later in life in a clinically relevant Twist1+/- mouse model of craniosynostosis. Gli1+ MSC depletion is observed both in Twist1+/- mice and in those with maternal exposure to citalopram. Citalopram is a selective serotonin reuptake inhibitor (SSRI), which is the most commonly prescribed class of antidepressant drugs. Maternal SSRI usage is also known as an environmental risk factor for craniosynostosis in humans. These results lead to the hypothesis that Twist1 and Tcf12 mutations may interplay with citalopram in exacerbating skull and neurocognitive defects in craniosynostosis, which will be tested in Aim 1. Aim 2 will determine cellular and molecular mechanisms by which gene mutations and maternal citalopram exposure act together to cause craniosynostosis. Aim 3 will use our newly developed MSC-based suture regeneration approach to determine whether and how MSC implantation mitigates skull and neurocognitive dysfunctions in craniosynostosis caused by gene mutations, citalopram, and their interactions. Collectively, our proposed studies build upon our previous discoveries, and our findings will be highly significant for improving the understanding of mechanisms underlying gene- environment interplay in craniosynostosis; it offers a unique opportunity for improving treatment of infants with craniosynostosis.