Insulin‐like growth factor 2 and short‐range stimulatory loops in control of human placental growth.
Insulin‐like growth factor 2 and short‐range stimulatory loops in control of human placental growth.
复制标题
胰岛素样生长因子 2 和短程刺激环控制人胎盘生长。
作者：
Rolf Ohisson;L. Holmgren;A. Glaser;Agnieszka Szpecht;Susan Pfeifer
妊娠早期人类胎盘（受孕后 3 个月内）的亚结构显示出“假恶性”特性。我们在这里通过原位杂交表明，胰岛素样生长因子 2 (IGF-2) 基因表达在细胞滋养层中特别活跃，而细胞滋养层在这些结构中占主导地位。由于妊娠早期胎盘提取物中的大多数胎盘 IGF-2 mRNA 是多聚体，因此 IGF-2 转录物的空间模式通常也定义了 IGF-2 的产生模式。在原代滋养层培养物中，因血清饥饿而处于静止状态。 IGF-2 通过激活细胞周期进入/进展而发挥人类胚胎生长因子的作用。尽管在胎盘发育过程中可以发现 1 型和 2 型 IGF 受体 mRNA 与 IGF-2 mRNA 共同分布（支持 IGF-2 的自分泌作用），但这些偶尔的模式仅限于增殖潜力较低的细胞滋养细胞。配体和受体表达模式的相互作用根据 IGF-2 参与早期人胎盘增殖表型的限速步骤进行讨论。
Substructures of the first‐trimester human placenta (within 3 months post‐conception) display ‘pseudo‐malignant’ properties. We show here, by in situ hybridization, that the insulin‐like growth factor 2 (IGF‐2) gene expression is particularly active in the cytotrophoblasts, which dominate these structures. Because the majority of placental IGF‐2 mRNA is polysomal in extracts of first‐trimester placenta, the spatial pattern of IGF‐2 transcripts generally also defines the pattern of IGF‐2 production. In primary trophoblast cultures, rendered quiescent by serum starvation. IGF‐2 performs as a human embryonic growth factor by activating cell cycle entry/progression. Although both type 1 and 2 IGF receptor mRNAs can be found co‐distributed with IGF‐2 mRNA during placental development (supporting an autocrine role for IGF‐2), these occasional patterns are confined to cytotrophoblasts with low proliferative potential. The reciprocity in ligand and receptor expression patterns are discussed in terms of rate‐limiting steps in the involvement of IGF‐2 in the proliferative phenotype of the early human placenta.