Wordinger R J, Clark A F, Agarwal R, Lambert W, McNatt L, Wilson S E, Qu Z, Fung B K
Department of Anatomy and Cell Biology and The North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, 76107, USA.
Invest Ophthalmol Vis Sci. 1998 Aug;39(9):1575-89.
To compare the mRNA expression of growth factor receptors in cultured human trabecular meshwork (HTM) cells with ex vivo HTM tissues and to determine whether HTM cells generate a physiologic response after exposure to exogenous growth factors.
The reverse transcription-polymerase chain reaction (RT-PCR) method was used to detect the expression of various growth factor receptor mRNAs using early passaged, cultured HTM cells from donors of several ages. RT-PCR on ex vivo HTM tissues from healthy donors and donors with glaucoma were also used to compare and contrast mRNA expression with cell culture results. After the exogenous administration of growth factors, cell proliferation and extracellular acidification rate studies were used to measure the functional responses of HTM cells to growth factors.
Amplification products of the expected size for 15 growth factor receptors were detected in cultured HTM cells and in ex vivo HTM tissues. The administration of exogenous growth factors showed that (a) hepatocyte growth factor (HGF), epidermal growth factor (EGF), insulinlike growth factor (IGF)-1, tumor necrosis factor (TNF) alpha, platelet-derived growth factor (PDGF)-AA, PDGF-BB, PDGF-AB, and basic fibroblast growth factor (FGF-2) stimulated cell proliferation, whereas FGF-1 (acidic), transforming growth factor (TGF) alpha, interleukin (IL)-1alpha, nerve growth factor (NGF), and FGF-7 (keratinocyte growth factor [KGF]) had no significant influence on cell proliferation; (b) TGF-beta isoforms significantly inhibited EGF-stimulated trabecular meshwork cell proliferation; and (c) FGF-1 (acidic), TGF-alpha, EGF, IL-1alpha, IL-1beta, HGF, TNF-alpha, PDGF-AA, and IGF-1 significantly stimulated extracellular acidification, whereas FGF-2 (basic), FGF-7 (KGF), TGF-beta1-beta3 and NGF had no significant influence on extracellular acidification.
These studies show that mRNA for numerous growth factor receptors can be detected in cultured HTM cells and in ex vivo HTM tissues. They also show that many of the receptors are functional, because exogenous growth factor administration elicits a physiologic response. In vivo, these receptors may be activated by growth factors present within the aqueous humor (aquecrine/paracrine) or by growth factors synthesized and released locally by trabecular meshwork cells themselves (autocrine). Specific growth factors acting through high-affinity receptors may be involved in maintaining the normal microenvironment of the HTM and also may be involved in the pathogenesis of primary open-angle glaucoma.
比较培养的人小梁网（HTM）细胞与离体HTM组织中生长因子受体的mRNA表达，并确定HTM细胞在暴露于外源性生长因子后是否产生生理反应。
采用逆转录-聚合酶链反应（RT-PCR）方法，检测来自多个年龄段供体的早期传代培养HTM细胞中各种生长因子受体mRNA的表达。还对健康供体和青光眼患者的离体HTM组织进行RT-PCR，以将mRNA表达与细胞培养结果进行比较和对比。在给予外源性生长因子后，采用细胞增殖和细胞外酸化率研究来测量HTM细胞对生长因子的功能反应。
在培养的HTM细胞和离体HTM组织中检测到了15种生长因子受体预期大小的扩增产物。给予外源性生长因子显示：（a）肝细胞生长因子（HGF）、表皮生长因子（EGF）、胰岛素样生长因子（IGF）-1、肿瘤坏死因子（TNF）α、血小板衍生生长因子（PDGF）-AA、PDGF-BB、PDGF-AB和碱性成纤维细胞生长因子（FGF-2）刺激细胞增殖，而FGF-1（酸性）、转化生长因子（TGF）α、白细胞介素（IL）-1α、神经生长因子（NGF）和FGF-7（角质形成细胞生长因子[KGF]）对细胞增殖无显著影响；（b）TGF-β亚型显著抑制EGF刺激的小梁网细胞增殖；（c）FGF-1（酸性）、TGF-α、EGF、IL-1α、IL-1β、HGF、TNF-α、PDGF-AA和IGF-1显著刺激细胞外酸化，而FGF-2（碱性）、FGF-7（KGF）、TGF-β1-β3和NGF对细胞外酸化无显著影响。
这些研究表明，在培养的HTM细胞和离体HTM组织中可检测到多种生长因子受体的mRNA。研究还表明，许多受体具有功能，因为给予外源性生长因子会引发生理反应。在体内，这些受体可能被房水内存在的生长因子（旁分泌/自分泌）或小梁网细胞自身合成并局部释放的生长因子（自分泌）激活。通过高亲和力受体起作用的特定生长因子可能参与维持HTM的正常微环境，也可能参与原发性开角型青光眼的发病机制。
