Metabonomics analysis of aqueous humor samples from cataract patients with branch retinal vein occlusion.

Cataract (CAT) has a very high incidence rate among the middle-aged and elderly, with most patients complicated by branch retinal vein occlusion (BRVO), a key cause of blindness. In this study, through metabolomic analysis of aqueous humor samples from CAT patients with BRVO, a total of 319 different metabolites were found, most of which belonged to the categories of carboxylic acids and derivatives, fatty acyls, and organooxygen compounds. The most typical metabolites were 3-methylhistidine and biliverdin, which were up-regulated, as well as the down-regulated beta-glycerophosphoric acid. Tricosanoic acid showed the most significant correlation with CAT+BRVO. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the most commonly related keywords for differentially expressed metabolites were biosynthesis of unsaturated fatty acids and synaptic vesicle cycle. These results can not only help to further understand the pathogenesis of CAT complicated by BRVO in clinical practice, but also provide some new therapeutic research directions.

Roles of N-glycosylation and lipidation in Wg secretion and signaling.

Wnt members act as morphogens essential for embryonic patterning and adult homeostasis. Currently, it is still unclear how Wnt secretion and its gradient formation are regulated. In this study, we examined the roles of N-glycosylation and lipidation/acylation in regulating the activities of Wingless (Wg), the main Drosophila Wnt member. We show that Wg mutant devoid of all the N-glycosylations exhibits no major defects in either secretion or signaling, indicating that N-glycosylation is dispensable for Wg activities. We demonstrate that lipid modification at Serine 239 (S239) rather than that at Cysteine 93 (C93) plays a more important role in regulating Wg signaling in multiple developmental contexts. Wg S239 mutant exhibits a reduced ability to bind its receptor, Drosophila Frizzled 2 (dFz2), suggesting that S239 is involved in the formation of a Wg/receptor complex. Importantly, while single Wg C93 or Wg S239 mutants can be secreted, removal of both acyl groups at C93 and S239 renders Wg incapable of reaching the plasma membrane for secretion. These data argue that lipid modifications at C93 and S239 play major roles in Wg secretion. Further experiments demonstrate that two acyl attachment sites in the Wg protein are required for the interaction of Wg with Wntless (Wls, also known as Evi or Srt), the key cargo receptor involved in Wg secretion. Together, our data demonstrate the in vivo roles of N-glycosylation and lipid modification in Wg secretion and signaling.

Pneumatic Retinopexy Involving the Use of Intravitreal Air Injection and Laser Photocoagulation for Rhegmatogenous Retinal Detachment in Phakic Eyes.

The clinical efficacy of pneumatic retinopexy (PR) using intravitreal pure air injection and laser photocoagulation for rhegmatogenous retinal detachment (RRD) remains unknown. Thirty-nine consecutive patients with RRD (39 eyes) were included in this prospective case series. All patients underwent two-step PR surgery containing pure air intravitreal injection and laser photocoagulation retinopexy during hospitalization. The main outcomes were best-corrected visual acuity (BCVA) and primary anatomic success rates after PR treatment. The mean follow-up was 18.3 ± 9.7 months, ranging from 6 to 37 months. The primary anatomic success rate was 89.7% (35/39) after PR treatment. Final reattachment of the retina was achieved in 100% of cases. Macular epiretinal membrane was developed in two patients (5.7%) among successful PR cases during the follow-up. The mean logMAR BCVA value was significantly improved from 0.94 ± 0.69 before surgery to 0.39 ± 0.41 after surgery. The average central retinal thickness was significantly thinner in the RRD eyes of macula-off patients (206.8 ± 56.13 µm) when compared with the fellow eyes (234.6 ± 48.4 µm) at the last follow-up (p = 0.005). This study concluded that an inpatient PR procedure with pure air injection and laser photocoagulation is a safe and effective approach to treating patients with RRD, who may achieve a high single-operation success rate and good visual acuity recovery.

Autophagy Protects Ocular Surface Against Overactivated Inflammation by Degrading Retinoic Acid-Induced Gene-I in Human Conjunctival Epithelial Cells.

Purpose: To evaluate the pathological role of autophagy in dry eye diseases by detecting the autophagic degradation of RIG-I, a master RNA-sensing receptor in cells. Methods: RNA-sequencing analysis and qPCR analysis of the expression level of genes related to IFN-I signaling pathway was used to evaluate the inflammatory level of cells overexpressed with RIG-I or empty vector, which was further confirmed by WB analysis. Chemical treatment (3-methyladenine, chloroquine, NH4Cl, rapamycin, torin 1 or trehalose) or gene knockdown was used to modulate autophagy. When the autophagy level was regulated, the autophagic degradation of RIG-I and its pathological role in dry eye diseases were determined by detecting the protein level of RIG-I and the level of cell inflammation. Results: Cells that overexpressed RIG-I showed increased expression of genes involved in the IFN-I signaling pathway compared with cells transfected with an empty vector. Inhibition of autophagy leaded to the accumulation of RIG-I in HCECs, combined with the aggravation of the RIG-I-mediated IFN-I signaling pathway. Contrarily, promoting the autophagic degradation of RIG-I by trehalose treatment could alleviate IFN-I signaling pathway. Conclusions: Autophagy could protect the ocular surface against IFN-I signaling pathway by degrading RIG-I in HCECs. This process may restrict the overactivation of inflammation in the pathological development of dry eye disease.

Efficacy of carbonic anhydrase inhibitors in management of cystoid macular edema in retinitis pigmentosa: A meta-analysis.

BACKGROUND: Carbonic anhydrase inhibitors (CAI) are often used in the treatment of cystoid macular edema (CME) in retinitis pigmentosa (RP) patients. The aim of this meta-analysis is to gain a better understanding of the overall efficacy of CAI treatment. METHODS: Databases including PubMed, EMBASE, and Cochrane Library were searched to identify relevant studies. Eligible studies were clinical trials of patients with RP assigned topical or oral CAIs such as dorzolamide and acetazolamide. Changes in central macular thickness (CMT) by OCT in µm and best-corrected visual acuity (BCVA) in log MAR equivalents were extracted and results compared between baseline and after treatment. RESULTS: 11 clinical reports were identified which included a total of 194 patients (358 eyes) available for analysis, with 59 patients (115 eyes) assigned oral CAI treatment and 135 patients (243 eyes) assigned topical CAI treatment. The combined results showed a significant reduction of macular edema, as calculated by baseline and final central macular thickness (CMT) based on OCT examination (46.02µm, 95%CI: -60.96, -31.08, I2 = 65%). However, the effect on visual acuity was inconsistent across studies. CONCLUSION: Based on non randomized controlled clinical studies, RP patients with CME who were treated with CAIs had better anatomical outcomes, but the effect on visual acuity was contradictory across studies. Multicenter prospective randomized controlled trials would be ideal to definitively test its clinical efficacy in RP patients.

Effects of miRNA-200b on the development of diabetic retinopathy by targeting VEGFA gene.

The present study explored the effect of miR-200b on the development of diabetic retinopathy (DR) by targeting vascular endothelial growth factor A (VEGFA) gene. The study populations consisted of 255 DR patients (case group) and 253 healthy people (control group), while the expressions of miR-200b and VEGFA mRNA were detected by quantitative real-time PCR (qRT-PCR). Bioinformatics software and dual-luciferase reporter assay were used to confirm VEGFA as a target gene of miR-200b Also, a total of 70 Wistar male rats were selected and randomly assigned into blank, normal control (NC), miR-200b mimics, miR-200b inhibitors, miR-200b inhibitors + silencing vascular endothelial growth factor A (siVEGFA), and siVEGFA groups (n=10/group) respectively. Streptozotocin (STZ)-induced rat models of DR were successfully established. VEGFA, transforming growth factor-ß1 (TGF-ß1), hepatocyte growth factor (HGF), and pigment epithelium-derived factor (PEDF) were detected using qRT-PCR and Western blotting. In comparison with the control group, the case group showed lower expression of miR-200b but higher expression of VEGFA mRNA. VEGFA was confirmed as a target gene of miR-200b Rats in the miR-200b mimics and siVEGFA groups exhibited higher expression of PEDF mRNA and protein but lower expressions of VEGFA, TGF-ß1, HGF protein, and mRNA than the NC group. There was no remarkable difference in expressions of PEDF, VEGFA, TGF-ß1, HGF protein, and mRNA between the miR-200b inhibitors + siVEGFA and NC groups. In conclusion, the present study demonstrated that miR-200b might alleviate DR development by down-regulating its target gene VEGFA.

The deubiquitinating enzyme Usp5 regulates Notch and RTK signaling during Drosophila eye development.

Usp5 belongs to the USP family of deubiquitinating enzymes (DUBs), which comprises the largest class of DUBs. We previously reported that loss of Usp5 impairs development of photoreceptors in Drosophila eyes, although the detailed mechanism remained unclear. In the present study, we demonstrate that Usp5 regulates both Notch and receptor tyrosine kinase (RTK) signaling. Loss of Usp5 results in upregulation of Notch signaling and downregulation of RTK signaling, leading to impaired photoreceptor development. Moreover, genetic rescue experiments with the DNA binding protein Suppressor of Hairless or Notch RNAi indicate that they mediate the regulation of RTK signaling by Usp5. The present study provides mechanistic insight into how Usp5 regulates photoreceptor differentiation by Notch and RTK signaling in the Drosophila eye.

Drosophila USP5 controls the activation of apoptosis and the Jun N-terminal kinase pathway during eye development.

The Jun N-terminal kinase pathway plays an important role in inducing programmed cell death (apoptosis) and is activated in a variety of contexts. The deubiquitinating enzymes (DUBs) are proteases regulating the protein stability by ubiquitin-proteasome system. Here, for the first time, we report the phenotypes observed during eye development that are induced by deleting Drosophila USP5 gene, which encodes one of the USP subfamily of DUBs. usp5 mutants displayed defects in photoreceptor differentiation. Using genetic epistasis analysis and molecular markers, we show that most of these phenotypes are caused by the activation of apoptosis and JNK pathway. These data may provide a mechanistic model for understanding the mammalian usp5 gene.

Hyperplastic discs differentially regulates the transcriptional outputs of hedgehog signaling.

Hedgehog (Hh) acts as a morphogen to activate the transcription of diverse target genes via its downstream effector Cubitus interruptus (Ci). Currently, it is less understood how Ci recruits co-factors to activate transcription. Here we report that hyperplastic discs (hyd), an E3 ubiquitin ligase, can differentially regulate the transcriptional outputs of Hh signaling. We show that loss of Hyd activity caused upregulation of some, but not all of Hh target genes. Importantly, Hyd does not affect the stability of Ci. Our data suggest that Hyd differentially restrains the transcriptional activity of Ci via selective association with respective promoters.

Upper and lower tear menisci in Sjögren's syndrome dry eye.

PURPOSE: To measure the tear menisci in Sjögren's syndrome dry eye (SSDE) by optical coherence tomography (OCT) and to determine its relationships with the clinical tests. METHODS: Twenty-six SSDE, 26 non-SSDE, and 26 control subjects completed the Ocular Surface Disease Index (OSDI) before OCT determination of upper tear meniscus volume (UTMV), lower tear meniscus volume (LTMV), and total tear meniscus volume (TTMV). These were followed by measurements of noninvasive tear breakup time (NITBUT), fluorescein tear breakup time (FTBUT), fluorescein staining, Schirmer test, and corneal confocal microscopy. RESULTS: UTMV, LTMV, and TTMV were the lowest in SSDE among the three groups (P < 0.05). High sensitivity and specificity of UTMV (1.0; 0.96), LTMV (0.92; 0.92), and TTMV (0.96; 0.96) were found in the diagnosis of SSDE. For SSDE, the areas under the UTMV, LTMV, and TTMV receiver operating characteristic curves were larger than those in NITBUT, FTBUT, and Schirmer test (P < 0.005). In the SSDE group, NITBUT was correlated with UTMV (R = 0.41) and TTMV (R = 0.39) (P < 0.05). Fluorescein staining score was significantly correlated with UTMV (R = -0.46), LTMV (R = -0.41), and TTMV (R = -0.53) (P < 0.05). Superficial epithelial cell density was correlated with UTMV (R = 0.18), LTMV (R = 0.51), and TTMV (R = 0.44) (P < 0.05). CONCLUSIONS: Tear menisci volumes estimated by OCT may have great potential in the diagnosis and monitoring of SSDE. They can also reflect ocular surface damage and tear film stability.

Relative axial myopia induced by prolonged light exposure in C57BL/6 mice.

Ambient lighting is essential for ocular development in many species, however, disruption in diurnal lighting cycle can affect the development in refraction and axial growth of the eye. This study investigated the effects of prolonged daily lighting on refraction and various optical components of the eye by raising C57BL/6 mice under three different light/dark cycles (18/6, 12/12 and 6/18). Egr-1 mRNA expression, apoptosis and histology of the retina and size of the scleral fibrils were evaluated in these three lighting cycles. Results showed that there was a trend of myopic development, increasing vitreous chamber depth and thinning of the retina in eyes from 6/18 to 18/6 groups. Retinal Egr-1 mRNA expression and diameter of scleral fibrils were reduced with the prolongation of daily lighting from 6/18 to 18/6. However, retinal apoptosis was not detected in all the groups. These results suggest that prolonged lighting can induce axial myopia in inbred mice. This model, which uses mice with similar genetic backgrounds, provides an alternative to the currently available models and therefore is useful for evaluation of refractive errors caused by changes in environmental illumination.

Genetic deletion of the adenosine A2A receptor confers postnatal development of relative myopia in mice.

PURPOSE: To critically evaluate whether the adenosine A2A receptor (A2AR) plays a role in postnatal refractive development in mice. METHODS: Custom-built biometric systems specifically designed for mice were used to assess the development of relative myopia by examining refraction and biometrics in A2AR knockout (KO) mice and wild-type (WT) littermates between postnatal days (P)28 and P56. Ocular dimensions were measured by customized optical coherence tomography (OCT), refractive state by eccentric infrared photorefraction (EIR), and corneal radius of curvature by modified keratometry. Scleral collagen diameter and density were examined by electron microscopy on P35. The effect of A2AR activation on collagen mRNA expression and on soluble collagen production was examined in cultured human scleral fibroblasts by real-time RT-PCR and a collagen assay kit. RESULTS: Compared with WT littermates, the A2AR KO mice displayed relative myopia (average difference, 5.1 D between P28 and P35) and associated increases in VC depth and axial length from P28 to P56. Furthermore, the myopic shift in A2AR KO mice was associated with ultrastructural changes in the sclera: Electron microscopy revealed denser collagen fibrils with reduced diameter in A2AR KO compared with WT. Last, A2AR activation induced expression of mRNAs for collagens I, III, and V and increased production of soluble collagen in cultured human scleral fibroblasts. CONCLUSIONS: Genetic deletion of the A2AR promotes development of relative myopia with increased axial length and altered scleral collagen fiber structure during postnatal development in mice. Thus, the A2AR may be important in normal refractive development.

Spontaneous axial myopia and emmetropization in a strain of wild-type guinea pig (Cavia porcellus).

PURPOSE: To describe a wild-type guinea pig strain with an incidence of spontaneous axial myopia, minimal pupil responses, lack of accommodation, and apparently normal spatial vision. Such a strain is of interest because it may permit the exploration of defective emmetropization and mapping of the underlying quantitative trait loci. METHODS: Twenty-eight guinea pigs were selected from 220 animals based on binocular myopia (exceeding -1.50 diopter [D]) or anisometropia (difference between both eyes exceeding 10 D) at 4 weeks of age. Refractions and pupil responses were measured with eccentric infrared photoretinoscopy, corneal curvature by modified conventional keratometer, and axial lengths by A-scan ultrasonography once a week. Twenty-one guinea pigs were raised under a normal 12-hour light/12-hour dark cycle. From a sample of 18 anisometropic guinea pigs, 11 were raised under normal light cycle and 7 were raised in the dark to determine the extent to which visual input guides emmetropization. Spatial vision was tested in an automated optomotor drum. RESULTS: In 10 guinea pigs with myopia in both eyes, refractive errors ranged from -15.67 D to -1.50 D at 3 weeks with a high interocular correlation (R = 0.82); axial length and corneal curvature grew almost linearly over time. Strikingly, two patterns of recovery were observed in anisometropic guinea pigs: in 12 (67%) anisometropia persisted, and in 6 (33%) it declined over time. These ratios remained similar in dark-reared guinea pigs. Unlike published strains, all guinea pigs of this strain showed weak pupil responses and no signs of accommodation but up to 3 cyc/deg of spatial resolution. CONCLUSIONS: This strain of guinea pigs has spontaneous axial refractive errors that may be genetically or epigenetically determined. Interestingly, it differs from other published strains that show no refractive errors, vivid accommodation, or pupil responses.