Department of Ophalmology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
In Vivo. 2011 Mar-Apr;25(2):179-84.
BACKGROUND/AIM: The E peptide of the IGF-1Ec transcript has been documented to stimulate the growth of different cell lines, via a type I IGF-1 receptor (IGF-1R)-independent mechanism. The aim of the present study was to determine the implication of the IGF-1Ec isoform into the posterior capsule opacification process in human lens epithelium.
The expression of the IGF-1 system was characterized in human HLE-B3 lens epithelium cells and the mitogenic activity of IGF-1 and synthetic E peptide and the effects of growth hormone (GH) and dihydrotestosterone (DHT) were examined, using qualitative real-time PCR, RT-PCR, Western blot analysis and trypan blue exclusion assays in wild-type and IGF-1R knock-out HLE-B3 cells.
The data showed that HLE-B3 cells express only the IGF-1Ea and IGF-1R transcripts. GH increased the expression of IGF-1Ea and of the previously undetectable IGF-1Eb mRNA. Finally, IGF-1 did not present any activity in the knock-out cells.
The IGF-1Ea isoform is the main source for the formation of mature IGF-1 in HLE-B3 cells. The effects of exogenous IGF-1 depend on the existence of IGF-1R. IGF-1 Ec is not expressed even in the presence of GH or DHT nor has it any effect on cell proliferation.
背景/目的：IGF-1Ec 转录物的 E 肽已被证明通过一种 IGF-1 型受体（IGF-1R）独立的机制刺激不同细胞系的生长。本研究旨在确定 IGF-1Ec 同工型在人晶状体上皮后囊混浊过程中的作用。
在人 HLE-B3 晶状体上皮细胞中对 IGF-1 系统的表达进行了特征描述，并使用定性实时 PCR、RT-PCR、Western blot 分析和台盼蓝排斥试验，在野生型和 IGF-1R 敲除 HLE-B3 细胞中检查了 IGF-1 和合成 E 肽的有丝分裂活性以及生长激素（GH）和二氢睾酮（DHT）的作用。
数据显示，HLE-B3 细胞仅表达 IGF-1Ea 和 IGF-1R 转录物。GH 增加了 IGF-1Ea 和以前未检测到的 IGF-1Eb mRNA 的表达。最后，IGF-1 在敲除细胞中没有任何活性。
IGF-1Ea 同工型是 HLE-B3 细胞中成熟 IGF-1 形成的主要来源。外源性 IGF-1 的作用取决于 IGF-1R 的存在。即使存在 GH 或 DHT，IGF-1Ec 也不会表达，也不会对细胞增殖产生影响。
