GPER在雌激素促进高氧期新生小鼠OIR血管发育中的作用机制研究

Retinopathy of prematurity (ROP) is one of major blinding diseases in children, while currently, the measures of treating it are focused on retinal neovascularization and the results are unsatisfactory. It has been found that the primary cause of disordered proliferation of immature retinal vascular network in neovascularization phase of ROP is vascular occlusion under the condition of prematurity and hyperoxia. Our previous studies have found that 17β-estradiol (E2) can promote the development of immature retinal vascular network in oxygen-induced retinopathy (OIR) (the model of ROP) in hyperoxic phase through anti-oxidative stress. Given that 17β-E2 is not a high selective agonist of estrogen receptor (ER) and ER can be divided into ERα, ERβ and G protein-coupled estrogen receptor (GPER/GPR30), ERα and ERβ can bind with estrogen response element and exert slow and long-lasting function, whereas GPER is mainly distributed in endoplasmic reticulum and can rapidly modulate endoplasmic reticulum stress, which plays an important role in oxidative stress, we design this study to further explore the role of GPER in protecting mice retinal capillary endothelium cells, retinal ganglion cells, astrocytes and microglia from high-oxygen provocation by rapidly modulating endoplasmic reticulum stress, and the molecular mechanisms of GPER in promoting retinal vascular development under hyperoxia. All these results will be further testified in OIR in hyperoxic phase, which may be beneficial to understand the pathomechanism of ROP in hyperoxic phase, and give help to the prophylaxis of ROP with high-selective E analogue in early stage.

早产儿视网膜病变（ROP）是儿童主要致盲性眼病之一，目前治疗方法主要针对后期的新生血管期病变，并发症多且效果不理想。已有充分证据表明ROP早期血管闭塞是后期新生血管生成的根本原因，课题组前期研究发现17β-雌二醇（E2）通过抗氧化应激（OS）促进早期高氧期OIR（ROP动物模型）视网膜血管发育，为用雌激素防治早期ROP提供了理论依据。鉴于17β-E2受体包括ERα、ERβ和GPER，ERα和ERβ通过基因途径发挥作用缓慢，而GPER分布于内质网，通过调节内质网应激发挥快速抗OS（内质网应激在OS中发挥重要作用），本课题组拟进一步研究高氧条件下，小鼠视网膜微血管内皮细胞、神经节细胞、星形胶质细胞和小胶质细胞内质网应激变化，GPER对这些变化的快速调控作用和促进视网膜血管继续发育的分子机制，并用高氧期OIR模型验证，为认识缺血期ROP病理机制和用高选择性雌激素类药物防治早期ROP提供实验依据。

背景：目前对早产儿视网膜病变（ROP）的研治主要针对后期新生血管（RNV），并发症多。ROP根本原因是早期视网膜血管发育(RVD)停止。课题组前期研究发现雌激素通过抗氧化应激（OS）促进早期OIR（ROP模型）RVD。雌激素膜受体GPER分布于内质网，通过调节内质网应激（ER stress）快速抗OS，本课题进一步研究GPER在其中的作用和机制。.内容：1）GPER在小鼠视网膜微血管内皮细胞（MRCECs）、神经节细胞（RGCs）、星形胶质细胞（astrocyte）和小胶质细胞（microglia）.表达。2）GPER激活对75%O2下上述细胞活力和ER stress的调控。3）GPER激活对高氧期OIR的RVD机制。.结果：GPER在上述细胞表达，GPER激活减轻75%O2诱发的ER stress，增强这些细胞活力，并降低其分泌HIF-1α、VEGF-A、IL-6、TNF-α和PDGF-A，增多LIF，促进75%O2下RVD。.关键数据：.1）培养72h75%O2下MRCECs、RGCs、astrocyte和microglia内质网IRE1α（灰度值）分别为高氧对照(HC)组41.91±1.23、G1组18.83±0.25和G1+G15组103.35±0.74（P<0.01），HC组46.16±4.55、G1组15.47±5.28和G1+G15组61.22±4.19（P<0.01），HC组29.52±3.04、G1组16.23±3.50和G1+G15组96.95±10.95（P<0.01），HC组33.47±5.04、G1组17.62±5.11和G1+G15组37.38±5.05（P<0.01）。.2）48小时OIR的IRE1α：HC组为31.76±0.42，G1组为19.28±0.59，G1+G15组为41.20±0.36（P<0.01）。.3）48小时OIR无灌注区比值：HC组为72.62±1.57%，G1组为40.87±1.51%，G1+G15组为53.47±0.58%（P<0.01）。.科学意义：发现GPER在MRCECs、RGCs、astrocyte和microglia表达，GPER激活减轻高氧诱发上述细胞内ER stress，显著促进高氧期OIR的RVD，为用GPER类药物防治早期ROP奠定理论基础。