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Abstract：
Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes a kinase that phosphorylates most of the secreted proteins found in the body fluids and extracellular matrix. The most common RNS clinical features are generalized osteosclerosis, facial dysmorphism, intracerebral calcifications and respiratory defects. In non-lethal RNS forms, oral traits include a well-studied hypoplastic amelogenesis imperfecta (AI) and a much less characterized gingival phenotype. We used immunomorphological, biochemical, and siRNA approaches to analyze gingival tissues and primary cultures of gingival fibroblasts of two unrelated, previously reported RNS patients. We showed that fibrosis, pathological gingival calcifications and increased expression of various profibrotic and pro-osteogenic proteins such as POSTN, SPARC and VIM were common findings. Proteomic analysis of differentially expressed proteins demonstrated that proteins involved in extracellular matrix (ECM) regulation and related to the TGFβ/SMAD signaling pathway were increased. Functional analyses confirmed the upregulation of TGFβ/SMAD signaling and subsequently uncovered the involvement of two closely related transcription cofactors important in fibrogenesis, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). Knocking down of FAM20C confirmed the TGFβ-YAP/TAZ interplay indicating that a profibrotic loop enabled gingival fibrosis in RNS patients. In summary, our in vivo and in vitro data provide a detailed description of the RNS gingival phenotype. They show that gingival fibrosis and calcifications are associated with, and most likely caused by excessed ECM production and disorganization. They furthermore uncover the contribution of increased TGFβ-YAP/TAZ signaling in the pathogenesis of the gingival fibrosis.
摘要：
雷恩综合征（RNS）是一种罕见的常染色体隐性骨硬化发育不良。RNS是由FAM20C基因的功能丧失疾病致病变体引起的，该基因编码一种激酶，该激酶磷酸化体液和细胞外基质中发现的大多数分泌蛋白。最常见的RNS临床特征是全身性骨硬化，面部畸形,脑内钙化和呼吸缺陷。在非致死RNS形式中，口腔特征包括经过充分研究的发育不良牙釉质发育不全（AI）和特征较少的牙龈表型。我们用免疫形态学,生物化学，和siRNA的方法来分析牙龈组织和牙龈成纤维细胞的两个无关的原代培养，先前报道的RNS患者。我们发现纤维化,病理性牙龈钙化和各种促纤维化和促成骨蛋白如POSTN的表达增加，SPARC和VIM是共同的发现。差异表达蛋白质的蛋白质组学分析表明，参与细胞外基质（ECM）调节并与TGFβ/SMAD信号通路相关的蛋白质增加。功能分析证实了TGFβ/SMAD信号的上调，随后发现了两种密切相关的转录辅因子在纤维形成中的重要作用。Yes相关蛋白（YAP）和具有PDZ结合基序（TAZ）的转录共激活因子。敲除FAM20C证实了TGFβ-YAP/TAZ相互作用，表明促纤维化环使RNS患者牙龈纤维化。总之,我们的体内和体外数据提供了RNS牙龈表型的详细描述。他们表明牙龈纤维化和钙化与，很可能是由于ECM生产过度和组织混乱造成的。他们还揭示了TGFβ-YAP/TAZ信号传导增加在牙龈纤维化的发病机理中的作用。
