During ocular development, periocular neural crest cells (pNC) migrate into the region between the lens and presumptive corneal epithelium to form the corneal endothelium and stromal keratocytes. Although defects in neural crest cell development are associated with ocular dysgenesis, very little is known about the molecular mechanisms involved in this process. This study focuses on the corneal endothelium, a monolayer of specialized cells that are essential for maintaining normal hydration and transparency of the cornea. In avians, corneal endothelial cells are first to be specified from the pNC during their migration into the presumptive corneal region. To investigate the signals required for formation of the corneal endothelium, we utilized orthotopic and heterotopic injections of dissociated quail pNC into chick ocular regions. We find that pNC are multipotent and that the nascent cornea is competent to induce differentiation of ectopically injected pNC into corneal endothelium. Injected pNC downregulate expression of multipotency transcription factors and upregulate genes that are consistent with ontogenesis of the chick corneal endothelium. Importantly, we showed that TGFβ2 is expressed by the nascent lens and the corneal endothelium, and that TGFβ signaling plays a critical role in changing the molecular signature of pNC in vitro. Collectively, our results demonstrate the significance of the ocular environmental cues towards pNC differentiation, and have potential implications for clinical application of stem cells in the anterior segment.

在眼部发育过程中，眼周神经嵴细胞 (pNC) 迁移到晶状体和假定角膜上皮之间的区域，形成角膜内皮和基质角膜细胞。尽管神经嵴细胞发育缺陷与眼发育不全有关，但对该过程中涉及的分子机制知之甚少。这项研究的重点是角膜内皮，这是一种单层特化细胞，对于维持角膜的正常水合作用和透明度至关重要。在鸟类中，角膜内皮细胞在迁移到假定的角膜区域期间首先从 pNC 中指定。为了研究角膜内皮形成所需的信号，我们利用原位和异位注射分离的鹌鹑 pNC 到鸡眼区域。我们发现 pNC 是多能的，新生角膜有能力诱导异位注射的 pNC 分化为角膜内皮。注射的 pNC 下调多能转录因子的表达并上调与鸡角膜内皮的个体发育一致的基因。重要的是，我们证明了TGFβ2由新生晶状体和角膜内皮表达，TGFβ 信号在体外改变 pNC 的分子特征中起着关键作用。总的来说，我们的结果证明了眼部环境线索对 pNC 分化的重要性，并对前节干细胞的临床应用具有潜在意义。