Up-regulation of VEGF by retinoic acid during hyperoxia prevents retinal neovascularization and retinopathy.

Retinopathy of prematurity (ROP) is directly associated with abnormal expression of retinal vascular endothelial growth factor (VEGF) in premature neonates. This study was to investigate whether the systemic administration of retinoic acid (RA) regulates retinal VEGF expression and prevents retinal neovascularization and retinopathy in the oxygen-induced retinopathy (OIR) mouse model. C57BL/6 mice were subjected to OIR by exposure to 75% oxygen from postnatal day (P) 7 to 12 of age. RA was intraperitoneally injected daily to pups from P6 to P9. Retinal whole mount staining and image analysis, immunostaining, Western blotting, quantitative RT-PCR, TUNEL assay, and electroretinography were performed to evaluate the effects of RA on VEGF expression, retinal neovascularization, and retinal neuron functions. Systemic administration of RA in OIR mice promoted retinal VEGF mRNA and protein expression in phase I; the stabilized level of VEGF in phase I supported retinal vascular development and counteracted vaso-obliteration in OIR mice. Subsequently, the excessive generation of VEGF in phase II was attenuated; the retinal vascular leakage and apoptotic cells were significantly ameliorated. As a result, RA significantly prevented the development of hypoxia-induced retinal neovascularization and retinopathy in OIR mice and improved the functional recovery of retinal neurons downstream of photoreceptor cells as measured by focal electroretinography. Systemic administration of RA regulates retinal VEGF expression and supports retinal vascular development in OIR mouse model. We propose that systemic administration of RA to extremely low birth weight, preterm infants during oxygen therapy could potentially be an effective therapeutic approach for the prevention of ROP.

Wang L ，Shi P ，Xu Z ，Li J ，Xie Y ，Mitton K ，Drenser K ，Yan Q ... -  《-》

IC100, a humanized therapeutic monoclonal anti-ASC antibody alleviates oxygen-induced retinopathy in mice.

Retinopathy of prematurity (ROP), which often presents with bronchopulmonary dysplasia (BPD), is among the most common morbidities affecting extremely premature infants and is a leading cause of severe vision impairment in children worldwide. Activations of the inflammasome cascade and microglia have been implicated in playing a role in the development of both ROP and BPD. Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is pivotal in inflammasome assembly. Utilizing mouse models of both oxygen-induced retinopathy (OIR) and BPD, this study was designed to test the hypothesis that hyperoxia induces ASC speck formation, which leads to microglial activation and retinopathy, and that inhibition of ASC speck formation by a humanized monoclonal antibody, IC100, directed against ASC, will ameliorate microglial activation and abnormal retinal vascular formation. We first tested ASC speck formation in the retina of ASC-citrine reporter mice expressing ASC fusion protein with a C-terminal citrine (fluorescent GFP isoform) using a BPD model that causes both lung and eye injury by exposing newborn mice to room air (RA) or 85% O2 from postnatal day (P) 1 to P14. The retinas were dissected on P14 and retinal flat mounts were used to detect vascular endothelium with AF-594-conjugated isolectin B4 (IB4) and citrine-tagged ASC specks. To assess the effects of IC100 on an OIR model, newborn ASC citrine reporter mice and wildtype mice (C57BL/6 J) were exposed to RA from P1 to P6, then 75% O2 from P7 to P11, and then to RA from P12 to P18. At P12 mice were randomized to the following groups: RA with placebo PBS (RA-PBS), O2 with PBS (O2-PBS), O2 + IC100 intravitreal injection (O2-IC100-IVT), and O2 + IC100 intraperitoneal injection (O2-IC100-IP). Retinal vascularization was evaluated by flat mount staining with IB4. Microglial activation was detected by immunofluorescence staining for allograft inflammatory factor 1 (AIF-1) and CD206. Retinal structure was analyzed on H&E-stained sections, and function was analyzed by pattern electroretinography (PERG). RNA-sequencing (RNA-seq) of the retinas was performed to determine the transcriptional effects of IC100 treatment in OIR. ASC specks were significantly increased in the retinas by hyperoxia exposure and colocalized with the abnormal vasculature in both BPD and OIR models, and this was associated with increased microglial activation. Treatment with IC100-IVT or IC100-IP significantly reduced vaso-obliteration and intravitreal neovascularization. IC100-IVT treatment also reduced retinal microglial activation, restored retinal structure, and improved retinal function. RNA-seq showed that IC100 treatment corrected the induction of genes associated with angiogenesis, leukocyte migration, and VEGF signaling caused by O2. IC100 also corrected the suppression of genes associated with cell junction assembly, neuron projection, and neuron recognition caused by O2. These data demonstrate the crucial role of ASC in the pathogenesis of OIR and the efficacy of a humanized therapeutic anti-ASC antibody in treating OIR mice. Thus, this anti-ASC antibody may potentially be considered in diseases associated with oxygen stresses and retinopathy, such as ROP.

Yuan H ，Chen S ，Duncan MR ，de Rivero Vaccari JP ，Keane RW ，Dalton Dietrich W ，Chou TH ，Benny M ，Schmidt AF ，Young K ，Park KK ，Porciatti V ，Elizabeth Hartnett M ，Wu S ... -  《-》

Regulation of vascular endothelial growth factor by oxygen in a model of retinopathy of prematurity.

Pierce EA ，Foley ED ，Smith LE 《archives of ophthalmology》

Role of the adrenergic system in a mouse model of oxygen-induced retinopathy: antiangiogenic effects of beta-adrenoreceptor blockade.

Ristori C ，Filippi L ，Dal Monte M ，Martini D ，Cammalleri M ，Fortunato P ，la Marca G ，Fiorini P ，Bagnoli P ... -  《-》

Phosphomannopentaose sulfate (PI-88) suppresses angiogenesis by downregulating heparanase and vascular endothelial growth factor in an oxygen-induced retinal neovascularization animal model.

Liang XJ ，Yuan L ，Hu J ，Yu HH ，Li T ，Lin SF ，Tang SB ... -  《MOLECULAR VISION》