Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico.
Invest Ophthalmol Vis Sci. 2011 Nov 21;52(12):8944-50. doi: 10.1167/iovs.11-8190.
Specific proteolytic cleavages of the hormone prolactin (PRL) generate vasoinhibins, a family of peptides (including 16-kDa PRL) that are able to inhibit the pathologic increase in retinal vasopermeability (RVP) associated with diabetes. Here the authors tested the ability of an adenoassociated virus type 2 (AAV2) vasoinhibin vector to inhibit vascular endothelial growth factor (VEGF)- and diabetes-induced RVP.
AAV2 vectors encoding vasoinhibin, PRL, or soluble VEGF receptor 1 (soluble FMS-like tyrosine kinase-1 [sFlt-1]) were injected intravitreally into the eyes of rats. Four weeks later, either VEGF was injected intravitreally or diabetes was induced with streptozotocin. Tracer accumulation was evaluated as an index of RVP using fluorescein angiography or the Evans blue dye method. RT-PCR verified transgene expression in the retina, and the intravitreal injection of an AAV2 vector encoding green fluorescent protein revealed transduced cells in the retinal ganglion cell layer. In addition, Western blot analysis of AAV2-transduced HEK293 cells confirmed the expression and secretion of the vector-encoded proteins.
The AAV2-vasoinhibin vector prevented the increase in tracer accumulation that occurs 24 hours after the intravitreal injection of VEGF. Diabetes induced a significant increase in tracer accumulation compared with nondiabetic controls. This increase was blocked by the AAV2-vasoinhibin vector and reduced by the AAV2-sFlt-1 vector. The AAV2-PRL vector had no effect.
These results show that an AAV2-vasoinhibin vector prevents pathologic RVP and suggest it could have therapeutic value in patients with diabetic retinopathy.
催乳素（PRL）的特定蛋白水解裂解产生血管抑制素，这是一种能够抑制与糖尿病相关的视网膜血管通透性（RVP）病理性增加的肽家族（包括 16kDa PRL）。作者在此测试了腺相关病毒 2 型（AAV2）血管抑制素载体抑制血管内皮生长因子（VEGF）和糖尿病诱导的 RVP 的能力。
将编码血管抑制素、PRL 或可溶性血管内皮生长因子受体 1（可溶性 FMS 样酪氨酸激酶 1[sFlt-1]）的 AAV2 载体眼内注射到大鼠的眼睛中。四周后，将 VEGF 眼内注射或用链脲佐菌素诱导糖尿病。使用荧光素血管造影或 Evans 蓝染料法评估示踪剂积聚作为 RVP 的指标。RT-PCR 证实了视网膜中的转基因表达，并且 AAV2 载体编码绿色荧光蛋白的眼内注射显示了视网膜神经节细胞层中的转导细胞。此外，AAV2 转导的 HEK293 细胞的 Western blot 分析证实了载体编码蛋白的表达和分泌。
AAV2-血管抑制素载体可防止在眼内注射 VEGF 后 24 小时发生的示踪剂积聚增加。与非糖尿病对照组相比，糖尿病诱导示踪剂积聚显著增加。这种增加被 AAV2-血管抑制素载体阻断，并被 AAV2-sFlt-1 载体减少。AAV2-PRL 载体没有影响。
这些结果表明 AAV2-血管抑制素载体可预防病理性 RVP，并表明其在糖尿病性视网膜病变患者中可能具有治疗价值。
