JP1, a polypeptide specifically targeting integrin αVß3, ameliorates choroidal neovascularization and diabetic retinopathy in mice.

Anti-vascular endothelial growth factor (VEGF) drugs have revolutionized the treatment of neovascular eye diseases, but responses are incomplete in some patients. Recent evidence shows that integrins are involved in the pathogenesis of neovascular age-related macular degeneration and diabetic retinopathy. JP1, derived from an optimized seven-amino-acid fragment of JWA protein, is a polypeptide specifically targeting integrin αVß3. In this study we evaluated the efficacy of JP1 on laser-induced choroidal neovascularization (CNV) and retinal vascular leakage. CNV mice received a single intravitreal (IVT) injection of JP1 (10, 20, 40 µg) or ranibizumab (RBZ, 10 µg). We showed that JP1 injection dose-dependently inhibited laser-induced CNV; the effect of RBZ was comparable to that of 20 µg JP1; a combined IVT injection of JP1 (20 µg) and RBZ (5 µg) exerted a synergistic effect on CNV. In the 3rd month after streptozotocin injection, diabetic mice receiving IVT injection of JP1 (40 µg) or RBZ (10 µg) once a week for 4 weeks showed significantly suppressed retinal vascular leakage. In both in vivo and in vitro experiments, JP1 counteracted oxidative stress and inflammation via inhibiting ROS/NF-κB signaling in microglial cells, and angiogenesis via modulating MEK1/2-SP1-integrin αVß3 and TRIM25-SP1-MMP2 axes in vascular endothelial cells. In addition, intraperitoneal injection of JP1 (1, 5 or 10 mg) once every other day for 3 times also dose-dependently inhibited CNV. After intraperitoneal injection of FITC-labeled JP1 (FITC-JP1) or FITC in laser-induced CNV mice, the fluorescence intensity in the CNV lesion was markedly increased in FITC-JP1 group, compared with that in FITC group, confirming that JP1 could penetrate the blood-retinal barrier to target CNV lesion. We conclude that JP1 can be used to design novel CNV-targeting therapeutic agents that may replace current invasive intraocular injections.

miR-498 promotes cell proliferation and inhibits cell apoptosis in retinoblastoma by directly targeting CCPG1.

PURPOSE: Retinoblastoma (Rb) is the most common intraocular tumor in children. MicroRNAs (miRNAs) play a crucial role in gene regulation and cell growth/apoptosis/differentiation. The current study aimed to investigate the role of miR-498 in Rb. METHODS: Quantitative real-time polymerase chain reaction (QRT-PCR) was used to test mRNA level of miR-498. http://www.targetscan.org and http://www.microrna.org were applied to predict target of miR-498. Dual-luciferase reporter assay was applied to investigate if miR-498 targeted cell cycle progression 1 (CCPG1). Western blot (WB) was carried out to assess CCPG1 protein levels. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay was used to evaluate cell proliferation. Annexin-V Fluorescein (FITC) was adopted to explore cell apoptosis. RESULTS: In Y79 cells, miR-498 was higher than in normal ARPE-19 cells. MiR-498 could recognize CCPG1-3' untranslated region (UTR). CCPG1 protein level was remarkably decreased when overexpressed miR-498, nevertheless, significantly increased when inhibiting miR-498. Y79 cells that were transfected with miR-498 mimics manifested notable cell apoptosis down-regulation and cell proliferation promotion; whereas, those transfected with miR-498 inhibitor displayed significant cell apoptosis up-regulation and cell proliferation inhibition compared with control group. CONCLUSION: Taken together, miR-498 promotes cell proliferation and inhibits cell apoptosis in Rb by directly targeting CCPG1.

Blocking IL-17A Alleviates Diabetic Retinopathy in Rodents.

BACKGROUND/AIMS: Interleukin (IL)-17A, a proinflammatory cytokine, has been implicated in several autoimmune diseases. However, it is unclear whether IL-17A is involved in diabetic retinopathy (DR), one of the most serious complications of autoimmune diabetes. This study aimed to demonstrate that IL-17A exacerbates DR by affecting retinal Müller cell function. METHODS: High glucose (HG)-treated rat Müller cell line (rMC-1) was exposed to IL-17A, anti-IL-17A-neutralizing monoclonal antibody (mAb) or/and anti-IL-17 receptor (R)A-neutralizing mAb for 24 h. For in vivo study, DR was induced by intraperitoneal injections of streptozotocin (STZ). DR model mice were treated with anti-IL-17A mAb or anti-IL-17RA mAb in the vitreous cavity. Mice that were prepared for retinal angiography were sacrificed two weeks after intravitreal injection, while the rest were sacrificed two days after intravitreal injection. RESULTS: IL-17A production and IL-17RA expression were increased in both HG-treated rMC-1 and DR retina. HG induced rMC-1 activation and dysfunction, as determined by the increased GFAP, VEGF and glutamate levels as well as the downregulated GS and EAAT1 expression. IL-17A exacerbated the HG-induced rMC-1 functional disorders, whereas either anti-IL-17A mAb or anti-IL-17RA mAb alleviated the HG-induced rMC-1 disorders. Intravitreal injections with anti-IL-17A mAb or anti-IL-17RA mAb in DR model mice reduced Müller cell dysfunction, vascular leukostasis, vascular leakage, tight junction protein downregulation and ganglion cell apoptosis in the retina. CONCLUSIONS: IL-17A aggravates DR-like pathology at least partly by impairing retinal Müller cell function. Blocking IL-17A is a potential therapeutic strategy for DR.

m6A-Mediated Upregulation of Imprinted in Prader-Willi Syndrome Induces Aberrant Apical-Basal Polarization and Oxidative Damage in RPE Cells.

Purpose: To reveal the clinical significance, pathological involvement and molecular mechanism of imprinted in Prader-Willi syndrome (IPW) in RPE anomalies that contribute to AMD. Methods: IPW expression under pathological conditions were detected by microarrays and qPCR assays. In vitro cultured fetal RPE cells were used to study the pathogenicity induced by IPW overexpression and to analyze its upstream and downstream regulatory networks. Results: We showed that IPW is upregulated in the macular RPE-choroid tissue of dry AMD patients and in fetal RPE cells under oxidative stress, inflammation and dedifferentiation. IPW overexpression in fetal RPE cells induced aberrant apical-basal polarization as shown by dysregulated polarized markers, disrupted tight and adherens junctions, and inhibited phagocytosis. IPW upregulation was also associated with RPE oxidative damages, as demonstrated by intracellular accumulation of reactive oxygen species, reduced cell proliferation, and accelerated cell apoptosis. Mechanically, N6-methyladenosine level of the IPW transcript regulated its stability with YTHDC1 as the reader. IPW mediated RPE features by suppressing MEG3 expression to sequester its inhibition on the AKT serine-threonine kinase (AKT)/mammalian target of rapamycin (mTOR) pathway. We also noticed that the mTOR inhibitor rapamycin suppresses the AKT/mTOR pathway to alleviate the IPW-induced RPE anomalies. Conclusions: We revealed that IPW overexpression in RPE induces aberrant apical-basal polarization and oxidative damages, thus contributing to AMD progression. We also annotated the upstream and downstream regulatory networks of IPW in RPE. Our findings shed new light on the molecular mechanisms of RPE dysfunctions, and indicate that IPW blockers may be a promising option to treat RPE abnormalities in AMD.

Lactylation-driven FTO targets CDK2 to aggravate microvascular anomalies in diabetic retinopathy.

Diabetic retinopathy (DR) is a leading cause of irreversible vision loss in working-age populations. Fat mass and obesity-associated protein (FTO) is an N6-methyladenosine (m6A) demethylase that demethylates RNAs involved in energy homeostasis, though its influence on DR is not well studied. Herein, we detected elevated FTO expression in vitreous fibrovascular membranes of patients with proliferative DR. FTO promoted cell cycle progression and tip cell formation of endothelial cells (ECs) to facilitate angiogenesis in vitro, in mice, and in zebrafish. FTO also regulated EC-pericyte crosstalk to trigger diabetic microvascular leakage, and mediated EC-microglia interactions to induce retinal inflammation and neurodegeneration in vivo and in vitro. Mechanistically, FTO affected EC features via modulating CDK2 mRNA stability in an m6A-YTHDF2-dependent manner. FTO up-regulation under diabetic conditions was driven by lactate-mediated histone lactylation. FB23-2, an inhibitor to FTO's m6A demethylase activity, suppressed angiogenic phenotypes in vitro. To allow for systemic administration, we developed a nanoplatform encapsulating FB23-2 and confirmed its targeting and therapeutic efficiency in mice. Collectively, our study demonstrates that FTO is important for EC function and retinal homeostasis in DR, and warrants further investigation as a therapeutic target for DR patients.

Interleukin-6 prevents NMDA-induced neuronal death via Gp130 signaling-dependent IP3R inhibition.

OBJECTIVE: To reveal the involvement of inositol 1,4,5-trisphosphate receptors (IP3R) and ryanodine receptors (RyR) in IL-6 prevention from neuronal apoptosis and necrosis induced by N-methyl-D-aspartate (NMDA). METHODS: Cerebellar granule neurons (CGNs) from 8-day-old rats were exposed to IL-6 for 8 days and then stimulated with NMDA for 30 min. The 2-aminoethoxydiphenyl borate (2-APB) and dantrolene (DAN) were used to antagonize IP3R and RyR, respectively. Anti-gp130 monoclonal antibody (mAb) was employed to neutralize gp130, a 130-kDa signal-transducing ß-subunit of IL-6 receptor complex. Neuronal apoptosis and necrosis were determined by TUNEL, fluorometric caspase-3 enzyme activity, annexin V-FITC/PI staining and ELISA. Western blot and real-time PCR measured IP3R1 and RyR2 expression, respectively. RESULTS: IL-6 prevented the elevation of TUNEL-positive cells and caspase-3 expression and activity, and also suppressed the increase in annexin V-FITC/PI-positive cells and DNA- and histone-associated nucleosomes in cultured CGNs evoked by NMDA. These anti-apoptotic and anti-necrotic effects of IL-6 were larger on DAN-treated cells than on 2-APB-exposed neurons, since 2-APB treatment alone significantly inhibited the neuronal apoptosis and necrosis but DAN exposure alone did not alter the apoptosis and necrosis induced by NMDA. In support of these results, IL-6 downregulated IP3R1 but did not affect RyR2 expression. All these IL-6 effects were blocked by anti-gp130 mAb. CONCLUSION: IL-6 prevention from NMDA-triggered Ca2+-induced Ca2+ release-mediated apoptosis and necrosis in CGNs depends on the inhibition of IP3R channel opening and expression rather than on RyR activity. IL-6 receptor-coupled gp130 signaling mediates this neuroprotection of IL-6 resistance to neuronal apoptosis and necrosis.

[Targeted sequencing identifies a hotspot mutation SNRNP200 p.S1087L correlates with novel phenotypes in retinitis pigmentosa].

OBJECTIVE: To identify the pathogenic mutation in a four-generation Chinese family with autosomal dominant retinitis pigmentosa (ADRP) and to analyze its associated clinical phenotypes. METHODS: Twelve participants from the index family were recruited, including 5 patients, 6 asymptomatic siblings, and one spouse. All participants underwent ophthalmic examinations, including best-corrected visual acuity (BCVA), visual field (VF) testing, fundus photography, and full-field flash electroretinography (ERG). Targeted sequence capture array technique with next-generation of high throughput sequencing(NGS) was performed to detect variants in 189 hereditary retinal disease (HRD) related genes, comprising 179 identified HRD-causing genes and 10 potential causative genes which were involved in pre-messenger RNA(pre-mRNA) splicing. Variants detected by targeted sequencing were filtered by bioinformatic analyses, validated by Sanger sequencing and intra-familiar analysis.Genotype-phenotype correlation was also analyzed. RESULTS: SNRNP200 p.S1087L was identified as the disease causative mutation for this family by targeted sequencing and optimized bioinformatic analyses. This family demonstrated early onset of the disease by presenting nyctalopia among 6 to 8 years old, performed rapid disease progression and severely impaired visual function by displaying loss of VF among 14 to 17 years old and decreased central vision among 21 to 28 years old. The fundus presentations and ERG results showed typical RP presentations. CONCLUSIONS: SNRNP200 p.S1087L is identified as a hotspot mutation but correlates with distinct phenotypes in the present family, including early onset of the disease, rapid disease progression, and severely impaired visual function. This study also give evidence to that molecular diagnostic platform for HRD can improve the detection rate of causative genes/mutations in HRD patients, thus providing important approaches for further investigation of the genetic causes for HRD.

Prediction of SMILE surgical cutting formula based on back propagation neural network.

AIM: To predict cutting formula of small incision lenticule extraction (SMILE) surgery and assist clinicians in identifying candidates by deep learning of back propagation (BP) neural network. METHODS: A prediction program was developed by a BP neural network. There were 13 188 pieces of data selected as training validation. Another 840 eye samples from 425 patients were recruited for reverse verification of training results. Precision of prediction by BP neural network and lenticule thickness error between machine learning and the actual lenticule thickness in the patient data were measured. RESULTS: After training 2313 epochs, the predictive SMILE cutting formula BP neural network models performed best. The values of mean squared error and gradient are 0.248 and 4.23, respectively. The scatterplot with linear regression analysis showed that the regression coefficient in all samples is 0.99994. The final error accuracy of the BP neural network is -0.003791±0.4221102 µm. CONCLUSION: With the help of the BP neural network, the program can calculate the lenticule thickness and residual stromal thickness of SMILE surgery accurately. Combined with corneal parameters and refraction of patients, the program can intelligently and conveniently integrate medical information to identify candidates for SMILE surgery.

ALKBH5 causes retinal pigment epithelium anomalies and choroidal neovascularization in age-related macular degeneration via the AKT/mTOR pathway.

Retinal pigment epithelium (RPE) dysfunction and choroidal neovascularization (CNV) are predominant features of age-related macular degeneration (AMD), with an unclear mechanism. Herein, we show that RNA demethylase α-ketoglutarate-dependent dioxygenase alkB homolog 5 (ALKBH5) is up-regulated in AMD. In RPE cells, ALKBH5 overexpression associates with depolarization, oxidative stress, disturbed autophagy, irregular lipid homeostasis, and elevated VEGF-A secretion, which subsequently promotes proliferation, migration, and tube formation of vascular endothelial cells. Consistently, ALKBH5 overexpression in mice RPE correlates with various pathological phenotypes, including visual impairments, RPE anomalies, choroidal neovascularization (CNV), and interrupted retinal homeostasis. Mechanistically, ALKBH5 regulates retinal features through its demethylation activity. It targets PIK3C2B and regulates the AKT/mTOR signaling pathway with YTHDF2 as the N6-methyladenosine reader. IOX1, an ALKBH5 inhibitor, suppresses hypoxia-induced RPE dysfunction and CNV progression. Collectively, we demonstrate that ALKBH5 induces RPE dysfunction and CNV progression in AMD via PIK3C2B-mediated activation of the AKT/mTOR pathway. Pharmacological inhibitors of ALKBH5, like IOX1, are promising therapeutic options for AMD.

Chordin-like 2 influences the differentiation fate of retinal pigment epithelium cells by dynamically regulating BMP pathway.

AIM: To explore the functions of Chordin-like 2, which is encoded by CHRDL2, in the process of retinal pigmented epithelium (RPE) differentiation and damage repair. METHODS: The fetal RPE cells (fRPE) was obtained from aborted fetus which obeyed medical ethics. Real-time quantitative polymerase chain reaction was used to measure expression quantity of CHRDL2 and other functional genes expression. Knocking down and overexpression was used to analyze the functions about Chordin-like 2. Enzyme-linked immunosorbent assay (ELISA) was used to detect the secretion of bone morphogenetic proteins 4 (BMP4). Flow cytometry was used to analyze cell cycle. Cell morphology was observed by phase contrast microscope (PCM). RESULTS: In normal RPE cells, CHRDL2 was firstly upregulated and followed a downregulation but eventually, it was expressed higher than the cells which undergone epithelial-mesenchymal transition (EMT). After knocking down CHRDL2, the secretion of BMP4 was decreased, RPE-related genes (OTX2, MITF, RPE65) were downregulated while EMT-related genes (SNAI1, VIM) were upregulated. However, the expression of these related genes after overexpression of CHRDL2 had contrary results. Chordin-like 2 also regulated the cell cycle by regulating BMP pathway. When CHRDL2 was knocked down, more fRPE cells stayed in S phase of cell cycle, while adding BMP4 reduced the proportion of the cells in S phase. However, overexpression of CHRDL2 increased more BMP4 secretion, this effect decreased the number of cells in S phase, but exogenous BMP inhibitor also could change this effect. At last, in the process of RPE cells differentiation, adding BMP4 at early stage could intervene normal RPE differentiation. Compared with BMP4, inhibiting BMP pathway had no significant negative effect at early stage, but suppressed differentiation at late stage. CONCLUSION: BMP pathway can be activated in a correct temporal order, otherwise, the cells have incorrect differentiation orientation. And Chordin-like 2 plays a role in dynamic regulation of BMP pathway and it also regulates the differentiation of RPE cells. Therefore, this research enlightens a new direction to inhibit EMT and promote cell redifferentiation after injury.

The Role of N6-Methyladenosine Modification in Microvascular Dysfunction.

Microvascular dysfunction (MVD) has long plagued the medical field despite improvements in its prevention, diagnosis, and intervention. Microvascular lesions from MVD increase with age and further lead to impaired microcirculation, target organ dysfunction, and a mass of microvascular complications, thus contributing to a heavy medical burden and rising disability rates. An up-to-date understanding of molecular mechanisms underlying MVD will facilitate discoveries of more effective therapeutic strategies. Recent advances in epigenetics have revealed that RNA methylation, an epigenetic modification, has a pivotal role in vascular events. The N6-methylation of adenosine (m6A) modification is the most prevalent internal RNA modification in eukaryotic cells, which regulates vascular transcripts through splicing, degradation, translation, as well as translocation, thus maintaining microvascular homeostasis. Conversely, the disruption of the m6A regulatory network will lead to MVD. Herein, we provide a review discussing how m6A methylation interacts with MVD. We also focus on alterations of the m6A regulatory network under pathological conditions. Finally, we highlight the value of m6A regulators as prognostic biomarkers and novel therapeutic targets, which might be a promising addition to clinical medicine.

m6A modification of circSPECC1 suppresses RPE oxidative damage and maintains retinal homeostasis.

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in the elderly population with unclear pathogenic mechanism. Herein, we detect downregulated circSPECC1 expression in retinal pigment epithelium (RPE) of AMD patients. In RPE cells, circSPECC1 insufficiency leads to oxidative stress-induced ferroptosis, depolarization, and irregular lipid metabolism. Consistently, in mice, circSPECC1 deficiency induces visual impairments and RPE anomalies and interrupts retinal homeostasis. Mechanically, nuclear export of circSPECC1 transcript depends on its N6-methyladenosine (m6A) level with YTHDC1 as the reader. CircSPECC1 directly sponges miR-145-5p to block its interaction with CDKN1A. Overexpressing miR-145-5p aggravates RPE dysfunctions, mimicking circSPECC1 silencing effects. Retinal phenotypes induced by circSPECC1 insufficiency are alleviated by miR-145-5p inhibition and are aggravated by miR-145-5p overexpression. Collectively, circSPECC1, mediated by m6A modification and sponging miR-145-5p, resists oxidative stress injuries and maintains lipid metabolism in RPE. Pharmacological supplementation of circSPECC1 is a promising therapeutic option for atrophic retinopathies like AMD.

Role of microRNA-25 in high glucose cultured Müller glia.

AIM: To investigate the role of microRNA-25 (miR-25) in proliferation and apoptosis of retinal Müller glia (MG) under high glucose condition. METHODS: The purity of the cultured cells was verified by immunocytochemistry and flow cytometry using antibodies that specifically recognized MG. The expression level of miR-25 under normal and high glucose conditions were validated by quantitative reverse transcription polymerase chain reaction (RT-qPCR). miR-25 mimics and negative control were transfected into MG and multiple functional experiments including cell counting kit-8 assay, EDU assay, and flow cytometry were conducted to explore the effects of miR-25 on the proliferation and apoptosis of high glucose cultured MG (HGMG). RESULTS: Immunocytochemistry and flow cytometry confirmed the high purity of primary cultured MG. RT-PCR results showed that the expression level of miR-25 was significantly repressed in HGMG, while over-expression of miR-25 by miR-25 mimic markedly inhibited the high glucose induced cell apoptosis and promoted the proliferation of MG. CONCLUSION: The expression level of miR-25 is significantly downregulated in HGMG and its overexpression could attenuate the high glucose damages on MG by promoting proliferation and reducing apoptosis.

IL-17A is involved in diabetic inflammatory pathogenesis by its receptor IL-17RA.

IMPACT STATEMENT: The participation of interleukin (IL)-17A in diabetic pathogenesis is suggested in animal models of autoimmune diabetes and in patients with type 1 diabetes (T1D), but with some contradictory results. Particularly, evidence for a direct injury of IL-17A to pancreatic ß cells is lacking. We showed that IL-17A deficiency alleviated diabetic signs including hyperglycemia, hypoinsulinemia, and inflammatory response in Ins2Akita (Akita) mice, a T1D model with spontaneous mutation in insulin 2 gene leading to ß-cell apoptosis. IL-17A enhanced inflammatory reaction, oxidative stress, and cell apoptosis but attenuated insulin level in mouse insulin-producing MIN6 cells. IL-17A had also a synergistic destruction to MIN6 cells with streptozotocin (STZ), a pancreatic ß-cell-specific cytotoxin. Blocking IL-17 receptor A (IL-17RA) reduced all these deleterious effects of IL-17A on MIN6 cells. The results demonstrate the role and the importance of IL-17A in T1D pathogenesis and suggest a potential therapeutic strategy for T1D targeting IL-17A and/or IL-17RA.

Rectangular 3-snip punctoplasty versus punch punctoplasty with silicone intubation for acquired external punctal stenosis: a prospective randomized comparative study.

AIM: To evaluate the effectiveness of rectangular 3-snip punctoplasty versus punch punctoplasty via Kelly punch with silicone intubation for the management of acquired external punctal stenosis (AEPS). METHODS: A prospective, randomized, comparative study was performed on 123 eyes of 94 patients with AEPS. Patients were recruited into either group of rectangular 3-snip punctoplasty (group A) or group of punch punctoplasty with silicone intubation (group B). Outcomes measured were Munk score, grade of punctal stenosis, fluorescein dye disappearance time test (FDDT) and tear meniscus height (TMH) 6 and 12mo after surgery. RESULTS: Twelve months after surgery, Munk score, FDDT and TMH significantly decreased in both groups compared with the baseline (all P<0.05), and grade of punctal stenosis increased significantly (P<0.05). The grade of punctal stenosis, Munk score, FDDT and TMH were better in group B compared with group A at 6 or 12mo (all P<0.05). There was a positive correlation between TMH and Munk score (R=0.655, P<0.001). At the last followed-up, anatomical success was noted in 96.7% eyes in group A and 98.4% eyes in group B (P=0.613). CONCLUSION: Punch punctoplasty via Kelly punch with silicone intubation achieves better outcomes than rectangular 3-snip punctoplasty. The new technique is a simple, minimally invasive, with high anatomical and functional success in patients with AEPS.

IL-17A injury to retinal ganglion cells is mediated by retinal Müller cells in diabetic retinopathy.

Diabetic retinopathy (DR), the most common and serious ocular complication, recently has been perceived as a neurovascular inflammatory disease. However, role of adaptive immune inflammation driven by T lymphocytes in DR is not yet well elucidated. Therefore, this study aimed to clarify the role of interleukin (IL)-17A, a proinflammatory cytokine mainly produced by T lymphocytes, in retinal pathophysiology particularly in retinal neuronal death during DR process. Ins2Akita (Akita) diabetic mice 12 weeks after the onset of diabetes were used as a DR model. IL-17A-deficient diabetic mice were obtained by hybridization of IL-17A-knockout (IL-17A-KO) mouse with Akita mouse. Primarily cultured retinal Müller cells (RMCs) and retinal ganglion cells (RGCs) were treated with IL-17A in high-glucose (HG) condition. A transwell coculture of RGCs and RMCs whose IL-17 receptor A (IL-17RA) gene had been silenced with IL-17RA-shRNA was exposed to IL-17A in HG condition and the cocultured RGCs were assessed on their survival. Diabetic mice manifested increased retinal microvascular lesions, RMC activation and dysfunction, as well as RGC apoptosis. IL-17A-KO diabetic mice showed reduced retinal microvascular impairments, RMC abnormalities, and RGC apoptosis compared with diabetic mice. RMCs expressed IL-17RA. IL-17A exacerbated HG-induced RMC activation and dysfunction in vitro and silencing IL-17RA gene in RMCs abolished the IL-17A deleterious effects. In contrast, RGCs did not express IL-17RA and IL-17A did not further alter HG-induced RGC death. Notably, IL-17A aggravated HG-induced RGC death in the presence of intact RMCs but not in the presence of RMCs in which IL-17RA gene had been knocked down. These findings establish that IL-17A is actively involved in DR pathophysiology and particularly by RMC mediation it promotes RGC death. Collectively, we propose that antagonizing IL-17RA on RMCs may prevent retinal neuronal death and thereby slow down DR progression.

Endothelium-derived semaphorin 3G attenuates ischemic retinopathy by coordinating ß-catenin-dependent vascular remodeling.

Abnormal angiogenesis and regression of the diseased retinal vasculature are key processes associated with ischemic retinopathies, but the underlying mechanisms that regulate vascular remodeling remain poorly understood. Here, we confirmed the specific expression of semaphorin 3G (Sema3G) in retinal endothelial cells (ECs), which was required for vascular remodeling and the amelioration of ischemic retinopathy. We found that Sema3G was elevated in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR) and in the neovascularization regression phase of oxygen-induced retinopathy (OIR). Endothelial-specific Sema3G knockout mice exhibited decreased vessel density and excessive matrix deposition in the retinal vasculature. Moreover, loss of Sema3G aggravated pathological angiogenesis in mice with OIR. Mechanistically, we demonstrated that HIF-2α directly regulated Sema3G transcription in ECs under hypoxia. Sema3G coordinated the functional interaction between ß-catenin and VE-cadherin by increasing ß-catenin stability in the endothelium through the neuropilin-2 (Nrp2)/PlexinD1 receptor. Furthermore, Sema3G supplementation enhanced healthy vascular network formation and promoted diseased vasculature regression during blood vessel remodeling. Overall, we deciphered the endothelium-derived Sema3G-dependent events involved in modulating physiological vascular remodeling and regression of pathological blood vessels for reparative vascular regeneration. Our findings shed light on the protective effect of Sema3G in ischemic retinopathies.

Displacement of the retina after idiopathic macular hole surgery with different internal limiting membrane peeling patterns.

AIM: To explore retinal displacement after surgical treatment for idiopathic macular hole (IMH) with different internal limiting membrane (ILM) peeling patterns. METHODS: Totally 22 eyes from 20 patients with IMH were randomly allocated into two groups, N-T group (11 eyes) and T-N group (11 eyes). For patients in N-T group, ILM was peeled off from nasal to temporal retina. For patients in T-N group, ILM was peeled off from temporal to nasal retina. Preoperative, postoperative 1, 3, and 6mo, autofluorescence fundus images were collected for manual measurement of distances of fixed nasal (N), temporal (T), superior (S), and inferior (I) retinal points (bifurcation or crossing of retinal vessels) around the macula to the optic disc (OD). These were respectively defined as N-OD, T-OD, S-OD, and I-OD. The retinal displacement, macular hole closure rate, and best corrected visual acuity (BCVA) were compared between the two groups after surgery. RESULTS: At postoperative 1, 3, and 6mo, the macula slipped toward the OD, manifested by the decreased T-OD, N-OD, S-OD, and I-OD (P<0.05). No significant difference was found in the T-OD, N-OD, S-OD, and I-OD between N-T group and T-N group. IMH closure rate was 100% both in N-T group and T-N group. There was no significant difference in BCVA between two groups (P<0.05). CONCLUSION: The macula slips toward the OD after successful macular hole surgery. The two different ILM peeling pattern show similar visual outcome and retinal displacement, which means ILM peeling directions are not the influencing factor of postoperative retinal displacement.

Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin inhibits the proliferation of ARPE-19 cells.

BACKGROUND: The antiproliferative effect of the Hsp90 inhibitor 17-AAG (17-allylamino-17-demethoxygeldanamycin) on human retinal pigment epithelial cells is investigated. METHODS: MTT and flow cytometry were used to study the antiproliferative effects of the 17-AAG treatment of ARPE-19 cells. 2D gel electrophoresis (2-DE) and mass spectrometry were applied to detect the altered expression of proteins, which was verified by real-time PCR. Gene Ontology analysis and Ingenuity Pathway Analysis (IPA) were utilized to analyze the signaling pathways, cellular location, function, and network connections of the identified proteins. And SOD assay was employed to confirm the analysis. RESULTS: 17-AAG suppressed the proliferation of ARPE-19 cells by inducing cell cycle arrest and apoptosis. Proteomic analysis revealed that the expression of 94 proteins was altered by a factor of more than 1.5 following exposure to 17-AAG. Of these 94, 87 proteins were identified. Real-time PCR results indicated that Hsp90 and Hsp70, which were not identified by proteomic analysis, were both upregulated upon 17-AAG treatment. IPA revealed that most of the proteins have functions that are related to oxidative stress, as verified by SOD assay, while canonical pathway analysis revealed glycolysis/gluconeogenesis. CONCLUSIONS: 17-AAG suppressed the proliferation of ARPE-19 cells by inducing cell cycle arrest and apoptosis, and possibly by oxidative stress.

Biomarkers in retinoblastoma.

Retinoblastoma (RB) is the most common intraocular malignancy of childhood caused by inactivation of the Rb genes. The prognosis of RB is better with an earlier diagnosis. Many diagnostic approaches and appropriate clinical treatments have been developed to improve clinical outcomes. However, limitations exist when utilizing current methods. Recently, many studies have identified identify new RB biomarkers which can be used in diagnosis, as prognostic indicators and may contribute to understanding the pathogenesis of RB and help determine specific treatment strategies. This review focuses on recent advances in the discovery of RB biomarkers and discusses their clinical utility and challenges from areas such as epigenetics, proteomics and radiogenomics.