Multiple genetic and environmental etiologies contribute to the pathogenesis of cleft palate, which is the most common of the inherited disorders of the craniofacial complex. Insights into the molecular mechanisms regulating osteogenic differentiation and patterning in the palate during embryogenesis are limited and needed for the development of innovative diagnostics and cures. This study used the Pax9-/- mouse model with a consistent phenotype of cleft secondary palate to investigate the role of Pax9 in the process of palatal osteogenesis. Although prior research has identified the upregulation of Wnt pathway modulators Dkk1 and Dkk2 in Pax9-/- palate mesenchyme, limitations of spatial resolution and technology restricted a more robust analysis. Here, data from single-nucleus transcriptomics and chromatin accessibility assays validated by in situ highly multiplex targeted single-cell spatial profiling technology suggest a distinct relationship between Pax9+ and osteogenic populations. Loss of Pax9 results in spatially restricted osteogenic domains bounded by Dkk2, which normally interfaces with Pax9 in the mesenchyme. Moreover, the loss of Pax9 leads to a disruption in the normal osteodifferentiaion of palatal osteogenic mesenchymal cells. These results suggest that Pax9-dependent Wnt signaling modulators influence osteogenic programming during palate formation, potentially contributing to the observed cleft palate phenotype.

中文翻译：

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空间多组学揭示了 Wnt 调节剂 Dkk2 在腭发生中的作用


多种遗传和环境病因导致腭裂的发病机制，腭裂是颅面复合体遗传性疾病中最常见的。对胚胎发生过程中调节上颚成骨分化和模式的分子机制的见解是有限的，并且需要开发创新的诊断和治疗方法。本研究使用具有一致次级腭裂表型的 Pax9-/-小鼠模型来研究 Pax9 在腭成骨过程中的作用。尽管先前的研究已经确定了 Wnt 通路调节剂 Dkk1 和 Dkk2 在 Pax9-/-上颚间充质中的上调，但空间分辨率和技术的限制限制了更稳健的分析。在这里，通过原位高度多重靶向单细胞空间分析技术验证的单核转录组学和染色质可及性测定的数据表明 Pax9 + 和成骨群体之间存在明显的关系。Pax9 的缺失导致以 Dkk2 为界的空间受限成骨结构域，该结构域通常与间充质中的 Pax9 连接。此外，Pax9 的缺失导致腭成骨间充质细胞正常骨分化的破坏。这些结果表明，Pax9 依赖性 Wnt 信号调节剂会影响腭形成过程中的成骨编程，可能有助于观察到的腭裂表型。