以β淀粉样蛋白作为早期AMD免疫干预新靶标的研究

Age-related Macular Degeneration (AMD) is the primary cause of blindness in senior people over 50yrs. A number of previous findings indicated that the deposit of Beta-Amyloid (Aβ) in drusen plays an important role in the pathogenesis of early-stage AMD. Previous report showed that the passive immune therapy targeting at Aβ had promising effects in the mouse model of AMD (APOE4-HFC). Due to the fact that the active immune therapy is usually more efficient in treating chronic diseases, we propose that the active immune therapy targeting at Aβ could become a more promising therapeutic approach in delaying the progress of early-stage AMD. The current proposal will: 1) explore the relationship of Aβ and the early-stage AMD in the ELOVL4 transgenic mouse, which model is the protypical pathological model of early-stage AMD; 2) further evaluate the clinical application of the Aβ-HSP60 peptide vaccine in the transgenic mouse mentioned above. The active immune therapy of Aβ-HSP60 peptide vaccine was known to have pronounced effect in the treatment of Alzheimer's disease, which disease has the similar pathogenesis as AMD. The therapeutic evaluation of the Aβ-HSP60 peptide vaccine will rely on the assessment of various characteristics of retina. The current proposal is significant in exploring the critical role of Aβ in the pathogenesis of early-stage AMD as well as evaluating the active immune therapy targeting at Aβ in the specific transgenic mouse model of AMD, which will lead to a novel therapeutic regimen of early-stage AMD in the future.

年龄相关性黄斑变性（AMD）是50岁以上人群失明的首要原因，日益增多的证据表明β淀粉样蛋白（Aβ）与玻璃膜疣的形成及早期AMD病变密切相关。已报道针对Aβ的被动免疫治疗在AMD小鼠模型（APOE4-HFC）上取得良好效果，而主动免疫更适合于AMD这类慢性疾病，因此我们推测针对Aβ的主动免疫治疗可更好的干预早期AMD。本课题拟采用前期构建的病理特征更为典型的早期AMD小鼠模型（ELOVL4转基因小鼠）进一步证实Aβ与早期AMD病变的相关性，并采用对具有相似病理特征的阿尔茨海默病小鼠模型治疗效果突出的新型Aβ多肽疫苗（Aβ-HSP60），对ELOVL4转基因小鼠进行主动免疫治疗，通过观测眼部相关指标的变化来观察其对早期AMD的疗效，从而验证我们的假说，为进一步阐明Aβ可作为早期AMD免疫治疗的新靶标奠定基础，同时建立以Aβ为靶标的早期AMD免疫治疗研究模型，对探索早期AMD的治疗具有重要意义。

年龄相关性黄斑变性（AMD）是50岁以上人群失明的首要原因，日益增多的证据表明β淀粉样蛋白（Aβ）与玻璃膜疣的形成及早期AMD病变密切相关，本研究以Aβ为早期AMD的靶标，探索主动免疫治疗对早期AMD的控制作用。首先，我们利用转基因技术构建早期AMD动物模型（ELOVL4转基因小鼠），探索Aβ与早期AMD眼部病变的相关性。研究结果表明：ELOVL4转基因小鼠在RPE与Brunch membrane之间可出现明显的Aβ沉积及表达，且随年龄增加而表达升高；同时ELOVL4转基因小鼠可出现明显的Drusen，RPE的破坏及Photoreceptor的退化，与年龄成正相关。研究结果表明，ELOVL4转基因小鼠的眼部Aβ表达与早期AMD病理程度密切相关。其次，我们利用基因重组技术表达Aβ1-15-HSP60多肽。研究结果表明：利用大肠杆菌系统成功获得重组Aβ1-15-HSP60多肽，通过鉴定可知Aβ1-15-HSP60多肽具有显著的免疫原性。最后，我们探索Aβ1-15-HSP60多肽对ELOVL4转基因小鼠的治疗作用。研究结果表明：主动免疫可诱导ELOVL4转基因小鼠血清针对Aβ1-15 IgG的出现，随着免疫次数的增加，小鼠血清Aβ1-15 IgG表达量明显上调；相对于未治疗组，治疗组在RPE与Brunch membrane之间的Aβ沉积及表达量明显较少；对治疗前后ELOVL4转基因小鼠眼部指标的检测发现，ELOVL4治疗组相对于未治疗组，Drusen减少，RPE的破坏减弱及Photoreceptor的退化减弱。 因此本研究的开展揭示了Aβ可作为早期AMD主动免疫治疗的新靶标，Aβ1-15-HSP60多肽疫苗对早期AMD动物模型具有显著的治疗作用，可为年龄相关性黄斑变性的早期预防和治疗提供新的途径和手段。