PDF(Pubmed)
Abstract：
Fibroblast growth factor (FGF) and transforming growth factor-beta (TGF-β) can regulate and/or dysregulate lens epithelial cell (LEC) behaviour, including proliferation, fibre differentiation, and epithelial-mesenchymal transition (EMT). Earlier studies have investigated the crosstalk between FGF and TGF-β in dictating lens cell fate, that appears to be dose dependent. Here, we tested the hypothesis that a fibre-differentiating dose of FGF differentially regulates the behaviour of lens epithelial cells undergoing TGF-β-induced EMT. Postnatal 21-day-old rat lens epithelial explants were treated with a fibre-differentiating dose of FGF-2 (200 ng/mL) and/or TGF-β2 (50 pg/mL) over a 7-day culture period. We compared central LECs (CLECs) and peripheral LECs (PLECs) using immunolabelling for changes in markers for EMT (α-SMA), lens fibre differentiation (β-crystallin), epithelial cell adhesion (β-catenin), and the cytoskeleton (alpha-tropomyosin), as well as Smad2/3- and MAPK/ERK1/2-signalling. Lens epithelial explants cotreated with FGF-2 and TGF-β2 exhibited a differential response, with CLECs undergoing EMT while PLECs favoured more of a lens fibre differentiation response, compared to the TGF-β-only-treated explants where all cells in the explants underwent EMT. The CLECs cotreated with FGF and TGF-β immunolabelled for α-SMA, with minimal β-crystallin, whereas the PLECs demonstrated strong β-crystallin reactivity and little α-SMA. Interestingly, compared to the TGF-β-only-treated explants, α-SMA was significantly decreased in the CLECs cotreated with FGF/TGF-β. Smad-dependent and independent signalling was increased in the FGF-2/TGF-β2 co-treated CLECs, that had a heightened number of cells with nuclear localisation of Smad2/3 compared to the PLECs, that in contrast had more pronounced ERK1/2-signalling over Smad2/3 activation. The current study has confirmed that FGF-2 is influential in differentially regulating the behaviour of LECs during TGF-β-induced EMT, leading to a heterogenous cell population, typical of that observed in the development of post-surgical, posterior capsular opacification (PCO). This highlights the cooperative relationship between FGF and TGF-β leading to lens pathology, providing a different perspective when considering preventative measures for controlling PCO.
摘要：
成纤维细胞生长因子（FGF）和转化生长因子-β（TGF-β）可以调节和/或失调晶状体上皮细胞（LEC）的行为，包括扩散，纤维分化，和上皮-间质转化（EMT）。早期的研究已经研究了FGF和TGF-β在决定晶状体细胞命运中的串扰，这似乎是剂量依赖性的。这里,我们检验了以下假设:纤维分化剂量的FGF差异调节经历TGF-β诱导的EMT的晶状体上皮细胞的行为。在7天的培养期内，用纤维分化剂量的FGF-2（200ng/mL）和/或TGF-β2（50pg/mL）处理出生后21天大的大鼠晶状体上皮外植体。我们比较了中央LEC（CLEC）和外周LEC（PLEC）使用免疫标记的EMT（α-SMA）标志物的变化，晶状体纤维分化（β-晶状体蛋白），上皮细胞粘附（β-连环蛋白），和细胞骨架（α-原肌球蛋白），以及Smad2/3-和MAPK/ERK1/2-信号。与FGF-2和TGF-β2共混的晶状体上皮外植体表现出不同的反应，CLEC接受EMT，而PLEC更喜欢晶状体纤维分化反应，与仅TGF-β处理的外植体相比，外植体中的所有细胞都经历了EMT。与FGF和TGF-β免疫标记α-SMA的CLEC，具有最少的β-晶状体蛋白，而PLECs表现出强的β-晶状体蛋白反应性和少量的α-SMA。有趣的是,与仅TGF-β处理的外植体相比，在与FGF/TGF-β共混的CLEC中，α-SMA显着降低。在FGF-2/TGF-β2共处理的CLEC中，Smad依赖性和非依赖性信号增加，与PLEC相比，Smad2/3的核定位细胞数量增加，相反，与Smad2/3激活相比，ERK1/2信号传导更为明显。目前的研究已经证实，FGF-2在TGF-β诱导的EMT过程中对LEC的行为有差异调节。导致异质细胞群，在术后发展中观察到的典型情况，后囊混浊（PCO）。这突出了FGF和TGF-β之间的合作关系，导致晶状体病理，在考虑控制PCO的预防措施时提供不同的观点。
