目的探讨外泌体(EXO)负载的抗新生血管短肽KV11在角膜新生血管(CNV)中的作用及其机制。
方法利用EXO锚定肽CP05将KV11结合到血管内皮来源的EXO膜表面，形成EXO-KV11。通过Apogee纳米流式分析EXO负载KV11的效率和最佳浓度比。选取8周龄SPF级健康雄性SD大鼠100只，其中10只大鼠不做任何处理，为正常对照组；其余大鼠在建立碱烧伤诱导CNV大鼠模型后，采用随机数字表法随机将大鼠分为EXO-KV11组、KV11组和生理盐水组，每组各30只。从碱烧伤后第1天开始每隔1天，各组分别结膜下注射100 μl EXO-KV11(25 μg)、KV11(25 μg)或生理盐水。观察第1、4、7、14天时CNV的生成情况；采用荧光素心室灌注、角膜血管造影法计算CNV面积；采用苏木精－伊红染色法观察各组CNV管腔数量；采用免疫组织化学法检测角膜组织中CD31的表达分布；采用Western blot法检测电压依赖性阴离子通道1(VDAC1)和内质网应激、自噬及凋亡相关蛋白的表达水平。
结果Apogee流式分析确定KV11与EXO最佳浓度比为4∶1，EXO负载KV11效率高达87.5%。碱烧伤后7 d和14 d，各组CNV面积总体比较差异均有统计学意义( F＝4.613、15.590，均 P<0.05)，其中碱烧伤后7 d，EXO-KV11组CNV面积小于KV11组和生理盐水组；碱烧伤后14 d，EXO-KV11组和KV11组CNV面积均小于生理盐水组，EXO-KV11组CNV面积小于KV11组，差异均有统计学意义(均 P<0.05)。角膜荧光铺片定量分析结果显示，生理盐水组、KV11组和EXO-KV11组CNV相对荧光面积分别为(8.3±1.7)%、(5.2±1.6)%和(3.4±0.7)%，总体比较差异有统计学意义( F＝11.735， P<0.01)，其中KV11组和生理盐水组CNV相对荧光面积均大于EXO-KV11组，生理盐水组CNV相对荧光面积大于KV11组，差异均有统计学意义(均 P<0.05)。碱烧伤后14 d，生理盐水组基质内可见大量新生血管管腔；KV11组基质内新生血管管腔数量较生理盐水组少；EXO-KV11组角膜结构趋于正常，少见新生血管管腔。生理盐水组角膜基质内可见大量CD31染色阳性细胞，细胞围成大小不一的管腔结构；KV11组角膜基质内CD31染色阳性细胞围成的管腔数量较生理盐水组少，EXO-KV11组管腔数量较KV11组少。EXO-KV11组、KV11组、生理盐水组和正常对照组VDAC1、蛋白质激酶R样内质网激酶(PERK)、自噬接头蛋白(SQSTM1/p62)、活化半胱氨酸蛋白酶3(cleaved caspase 3)相对表达量总体比较差异均有统计学意义( F＝35.960、8.947、17.791、101.168，均 P<0.01)，其中EXO-KV11组VDAC1、PERK、p62、cleaved caspase 3相对表达量高于KV11组和生理盐水组，差异均有统计学意义(均 P<0.001)。各组自噬微管相关蛋白轻链3B(LC3B)Ⅱ/LC3BⅠ蛋白相对表达量总体比较，差异无统计学意义( F＝0.445， P＝0.727)。
结论与KV11相比，EXO-KV11可通过增加VDAC1表达、刺激PERK产生、抑制自噬流的发生等机制更有效地抑制CNV。
ObjectiveTo investigate the effects and mechanism of exosome (EXO)-loaded kringle V11 (KV11) delivery on corneal neovascularization (CNV).
MethodsKV11 was bound to the surface of endothelial cell-derived exosomes by using CP05, an EXO-targeting anchoring peptide, to produce EXO-KV11.The binding efficiency and optimal concentration ratio were determined using the Apogee flow system.A total of 100 8-week-old healthy male SPF grade SD rats were selected, 10 of which were randomly selected as a normal control group without any treatment.The CNV model was established by alkali burn in the other 90 rats, which were randomly divided into three groups, EXO-KV11 group, KV11 group, and normal saline group by the random number table method, with 30 rats in each group.Each group was injected subconjunctivally with 100 μl of EXO-KV11 (25 μg), KV11 (25 μg), or normal saline every other day from the first day after the alkali burn, respectively.The CNV of rats was observed on days 1, 4, 7, and 14 after alkali burn.The CNV area was calculated by ventricular perfusion with fluorescein isothiocyanate-dextran (FITC-dextran) and corneal angiography.The amount of CNV lumen was observed by hematoxylin and eosin staining.The distribution of CD31 in rat corneas was determined by immunohistochemical method.The expression levels of voltage-dependent anion channel 1(VDAC1), endoplasmic reticulum stress, autophagy and apoptosis-associated proteins were detected by Western blot.This study was approved by the Animal Ethics Committee of Peking University People's Hospital (No.20210019). All animal procedures complied with the regulations of the Vision and Ophthalmology Association and the Animal Protection and Use Committee of Peking University.
ResultsThe optimal concentration ratio of KV11 to EXO was 4∶1 and the binding affinity reached up to 87.5% by Apogee flow cytometers.On days 7 and 14 after alkali burn, there were significant differences in CNV area among the four groups ( F=4.613, 15.590; both at P<0.05). On day 7 after alkali burn, the CNV area was smaller in EXO-KV11 group than in KV11 and normal saline groups, with statistically significant differences (both at P<0.05). On day 14 after alkali burn, the CNV area was smaller in EXO-KV11 and KV11 groups than in normal saline group, and smaller in EXO-KV11 group than in KV11 group, showing statistically significant differences (all at P<0.05). The results of quantitative analysis of corneal fluorescence mounts showed that the relative CNV fluorescence area of the normal saline group, KV11 group and EXO-KV11 group were (8.3±1.7)%, (5.2±1.6)%and (3.4±0.7)%, respectively, showing a statistically significant overall comparison difference ( F=11.735, P<0.01). The relative CNV fluorescence area was larger in KV11 and normal saline groups than in EXO-KV11 group, and larger in normal saline group than in KV11 group, showing statistically significant differences (all at P<0.05). On day 14 after alkali burn, massive neovascular lumens were observed in the matrix of the normal saline group.The number of neovascular lumens in KV11 group was smaller than that in normal saline group.The corneal structure appeared normal in EXO-KV11 group, and neovascular lumens were rare.Numerous CD31-positive cells were observed in the corneal stroma of the normal saline group, which formed into lumen structures.The number of lumens surrounded by CD31-positive cells in the corneal stroma was smaller in KV11 group than in normal saline group, and smaller in EXO-KV11 group than in KV11 group.There were significant differences in the relative expression levels of VDAC1, protein kinase R-like endoplasmic reticulum kinase (PERK), p62, cleaved caspase 3 among the four groups ( F=35.960, 8.947, 17.791, 101.168; all at P<0.01). The relative expression levels of VDAC1, PERK, p62, cleaved caspase 3 were higher in EXO-KV11 group than in KV11 and normal saline groups, showing statistically significant differences (all at P<0.001). There was no significant difference in the relative expression of microtubule-associated proteins 1A/1B light chain 3B (LC3B)Ⅱ/LC3BⅠ protein among all four groups ( F=0.445, P=0.727).
ConclusionsEXO-KV11 can inhibit CNV more remarkably than KV11.EXO-KV11 inhibits CNV by promoting the expression of VDAC1 and PERK and suppressing the autophagic flux.
陈文倩,杜玮,于文贞. 外泌体负载的KV11通过VDAC1和自噬机制对角膜新生血管的抑制作用[J]. 中华实验眼科杂志,2024,42(02)：108-116.
DOI:10.3760/cma.j.cn115989-20220402-00132版权归中华医学会所有。
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陈文倩：设计实验、实施研究、统计分析、起草文章；杜玮：设计实验、对文章知识性内容进行审阅和智力性内容修改；于文贞：直接参与选题、酝酿和设计实验、对文章的知识性内容作批评性审阅及定稿
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