Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan.
Invest Ophthalmol Vis Sci. 2013 Jun 3;54(6):3815-29. doi: 10.1167/iovs.12-11236.
Although heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been reported to have protective effects against various neuronal cell damage, its role in the retina has not been elucidated. Here, we investigated its role in light-induced photoreceptor degeneration using retinas and ventral forebrain-specific Hb-egf knockout (KO) mice.
Disruption of Hb-egf was confirmed by β-galactosidase (LacZ) staining and RT-PCR. Time-dependent changes in retinal HB-EGF were measured using quantitative RT-PCR and Western blotting. Retinal damage was induced by exposure to light. Recombinant human HB-EGF was injected intravitreally. Electroretinogram (ERG) and histological analyses were performed. To evaluate the effect of HB-EGF against light irradiation-induced cell death, 661W cells, a transformed mouse cone cell line, were used.
LacZ-positive cells were observed and Hb-egf deletion was confirmed in the retinas of Hb-egf KO mice. Hb-egf and pro-HB-EGF levels were increased after light exposure in wild-type (WT) mice. Exposure to light reduced the a- and b-wave amplitudes of the dark-adapted ERG, and also outer nuclear layer (ONL) thickness, in Hb-egf KO mice versus WT mice. Treatment with HB-EGF improved both the a- and b-wave amplitudes and the thickness of the ONL. The 661W cell death induced by light irradiation was exacerbated by Hb-egf knockdown. HB-EGF also protected against light-induced cell death and reduced reactive oxygen species (ROS) production in 661W cells. HB-EGF treatment improved the a-wave amplitudes and the thickness of the ONL in Hb-egf KO mice.
These data suggest that HB-EGF plays a pivotal role in light-induced photoreceptor degeneration. It therefore warrants investigation as a potential therapeutic target for such light-induced retinal diseases as age-related macular degeneration.
虽然肝素结合表皮生长因子样生长因子（HB-EGF）已被报道具有对抗各种神经元细胞损伤的保护作用，但它在视网膜中的作用尚未阐明。在这里，我们使用视网膜和腹侧前脑特异性 Hb-egf 敲除（KO）小鼠研究了其在光诱导的光感受器变性中的作用。
通过β-半乳糖苷酶（LacZ）染色和 RT-PCR 确认 Hb-egf 的缺失。使用定量 RT-PCR 和 Western blot 测量视网膜 HB-EGF 的时间依赖性变化。通过暴露于光来诱导视网膜损伤。将重组人 HB-EGF 眼内注射。进行视网膜电图（ERG）和组织学分析。为了评估 HB-EGF 对光照射诱导的细胞死亡的作用，使用了 661W 细胞，一种转化的小鼠锥体细胞系。
在 Hb-egf KO 小鼠的视网膜中观察到 LacZ 阳性细胞，并确认了 Hb-egf 的缺失。在野生型（WT）小鼠中，暴露于光后 Hb-egf 和前 HB-EGF 水平增加。与 WT 小鼠相比，Hb-egf KO 小鼠的光暴露降低了暗适应 ERG 的 a-和 b-波幅度以及外核层（ONL）厚度。HB-EGF 治疗改善了 a-和 b-波幅度以及 ONL 的厚度。光照射诱导的 661W 细胞死亡因 Hb-egf 敲低而加剧。HB-EGF 还可防止光诱导的细胞死亡并减少 661W 细胞中的活性氧（ROS）产生。HB-EGF 治疗改善了 Hb-egf KO 小鼠的 a-波幅度和 ONL 厚度。
这些数据表明 HB-EGF 在光诱导的光感受器变性中发挥关键作用。因此，它作为一种潜在的治疗靶点，值得研究用于治疗与年龄相关的黄斑变性等光诱导的视网膜疾病。
