Project description:Small nucleolar RNAs (snoRNAs) are small non-coding regulatory RNAs that have been investigated extensively in recent years. However, the relationship between snoRNA and glaucoma is still unknown. This study aims to analyze the levels of snoRNA expression in the aqueous humor (AH) of patients with pseudoexfoliation glaucoma (PEXG) compared to a control group and identify hypothetical snoRNA-dependent mechanisms contributing to PEXG. The AH was obtained from eighteen Caucasian patients, comprising nine PEXG and nine age-matched control patients. RNA was isolated, and a microarray system was used to determine the snoRNA expression profiles. Functional and enrichment analyses were performed. We identified seven snoRNAs, SNORD73B, SNORD58A, SNORD56, SNORA77, SNORA72, SNORA64, and SNORA32, in the AH of the PEXG and control group patients. Five snoRNAs showed statistically significantly lower expression in the PEXG group, and two snoRNAs had statistically significantly higher expression in the PEXG group compared to the control group. In addition, we identified two factors-CACNB3 for SNORA64 and TMEM63C for SNORA32, similar to PEX-related genes (CACNA1A and TMEM136). The enrichment analysis for four genes targeted by snoRNAs revealed possible mechanisms associated with glaucoma and/or PEX, but the direct role of snoRNAs in these biological processes was not proven.
Project description:Pseudoexfoliation (PEX) syndrome, one of the most common causes of glaucoma, represents a complex, multifactorial, late-onset disease of worldwide significance. The etiopathogenesis involves both genetic and non-genetic factors. The PEX-specific tissue alterations are caused by a generalized fibrotic matrix process, which has been characterized as a stress-induced elastosis associated with the excessive production and abnormal cross-linking of elastic microfibrils into fibrillar PEX aggregates. The identification of lysyl oxidase-like 1 (LOXL1) as a major genetic risk factor for PEX syndrome and PEX glaucoma further supports a role of elastogenesis and elastosis in the pathophysiology of PEX, as LOXL1 is a pivotal cross-linking enzyme in elastic fiber formation and stabilization. The available data suggest that LOXL1 is markedly dysregulated depending on the stage of the fibrotic process. While transient upregulation of LOXL1 during the early stages of PEX fibrogenesis participates in the formation and aggregation of abnormal PEX fiber deposits, the decreased expression of LOXL1 during the advanced stages of the disease may affect elastin metabolism and promote elastotic processes, e.g. in the lamina cribrosa, predisposing to glaucoma development. However, in view of the low penetrance of the PEX-associated risk variants of LOXL1, other genetic and/or environmental factors must contribute to the risk of developing the PEX phenotype. Some evidence exists for the contribution of additional genes with relatively small effects, e.g. clusterin (CLU), contactin-associated protein-like 2 (CNTNAP2), apolipoprotein E (APOE), glutathione S-transferases (GSTs), and tumor necrosis factor-alpha (TNFA), in certain study populations. Several environmental conditions associated with PEX, such as oxidative stress as well as pro-fibrotic cytokines and growth factors, can regulate expression of LOXL1 and elastic proteins in vitro and may therefore act as co-modulating external factors. Ultimately, both detection and functional characterization of yet unidentified genetic and non-genetic factors may lead to the development of more precise screening tools for the risk of PEX glaucoma.
Project description:Recent studies have shed new light on the genetic factors underlying pseudoexfoliation syndrome, growing our understanding of the role of the lysyl oxidase-like 1 (LOXL1) gene and its various polymorphisms as well as identifying new genetic associations. Recent years have brought new insight on how these genetic factors interact with other factors, including environmental, to confer risk to individuals and populations worldwide. All of these findings may hold importance to the screening, diagnosis, and monitoring of pseudoexfoliation and may also help lead to the identification of novel therapeutic targets. This review serves as an update on the recent trends and findings in pseudoexfoliation syndrome.
Project description:Purpose:To compare long-term effects of trabeculectomy on pseudoexfoliation glaucoma (PXG) and primary open-angle glaucoma (POAG). Methods:This retrospective case-control study included 53 eyes of PXG and 76 eyes of POAG. Intraocular pressure (IOP), number of antiglaucoma medications used, surgical success rate, and occurrence of complications were observed and statistically analyzed in both groups at 3 and 6 months and at 1, 3, and 5 years after trabeculectomy. Surgical success was defined according to the following 3 criteria: (1) IOP???21?mmHg; (2) IOP???18?mmHg; (3) IOP???15?mmHg. Complete success is defined as patients met these criteria without medical treatment, and qualified success is defined as patients met these criteria with medical treatment (?3 medications). Cumulative probabilities of success were compared using the Kaplan-Meier survival analysis. Results:For the 3 criteria, there were no statistically significant differences in complete and qualified success rates between the two groups at 3 and 6 months after trabeculectomy (P > 0.05). For criterion A, complete success rates in PXG at 3 and 5 years after surgery were lower than those in POAG; for criterion B, complete and qualified success rates in PXG at 3 and 5 years after surgery were lower than those in POAG; for criterion C, complete and qualified success rates in PXG at 1, 3, and 5 years after surgery were lower than those in POAG, the differences were statistically significant (P < 0.05). Conclusions:The short-term success rates of both types of glaucoma were similar; however, the long-term success rate of PXG was significantly lower, and it was difficult to achieve long-term control of IOP at a low target level.
Project description:PurposeTo investigate the microRNA (miRNA) profile in patients with different stages of pseudoexfoliation (PXF).MethodsPeripheral blood of patients with PXF (naïve to medical therapy and with no systemic disease/drugs) with ocular hypertension (OHT) and pseudoexfoliation glaucoma (PXG) was evaluated in triplicate for miRNA profiling using polymerase chain reaction (PCR) arrays. Those identified in the discovery stage were validated with evaluation of serum transforming growth factor-β1 (TGF-β1) levels by ELISA. The downstream targets of TGF-β1 and unfolded protein response (UPR) were analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Predicted targets of the identified miRNA and KEGG pathway analysis were done using miRbase and DIANA tools mirPathv3.1.ResultsWe found hsa-miR-122-5p, hsa-miR-124-3p and hsa-miR-424-5p to be upregulated in PXG targeting 3 specific pathways namely TGF-β1, fibrosis/ECM and proteoglycan metabolism with common effectors like SMAD/3/2. The unfolded protein response (UPR) genes were significantly downregulated in all stages of PXF suggesting this as the key mechanism for protein aggregates in PXF syndrome. Serum TGF-β1 was significantly upregulated as disease progressed to later stages in PXG. This elevation in advanced stages was associated with significantly differential expression of downstream pathways and fibrotic genes in OHT compared to PXG predominantly through the SMAD3, a canonical pathway marker.ConclusionCirculatory miRNA differentially regulating TGF-β1 and downstream targets including UPR genes may be the key mechanisms for glaucoma onset in PXF.
Project description:The present knowledge on the association of single nucleotide polymorphisms (SNPs) of lysyl oxidase-like 1 (LOXL1) with pseudoexfoliation syndrome (PEXS) and pseudoexfoliation glaucoma (PEXG) is controversial and inconclusive. This meta-analysis sought to derive a more precise estimation of the effects of LOXL1 SNP loci (rs1048661, rs3825942, and rs2165241) on PEXS/PEXG. Literature searches were conducted on the PubMed, EMBASE, ISI Web of Science, and Cochrane Library databases through October 2013. Twelve studies describing 1810 cases and 1790 controls met the inclusion criteria. The strengths of the associations found through the meta-analysis were assessed with pooled odds ratios and their 95% confidence intervals (CI). A meta-regression analysis was also used to examine the influence of the study and population characteristics. The results indicated that rs1048661 TT carriers had 92.1% and 40.4% less risk of developing PEXS/PEXG than did the controls in the Caucasian and Asian populations, respectively. Carriers of rs3825942 AA or rs2165241 CC also had significantly less PEXS/PEXG susceptibility than did the non-carriers. Meta-regression showed that in Caucasians, the male proportion (slope: 0.272; 95% CI: 0.167-0.376; P = 0.0001) and mean age (slope: 0.796; 95% CI: 0.375-1.217; P = 0.0002) of the PEXS/PEXG subjects correlated positively with the effect of rs3825942 on PEXS/PEXG susceptibility. The meta-analysis suggested that LOXL1 rs1048661 TT, rs3825942 AA, and rs2165241 CC were associated with a reduced risk of developing PEXS/PEXG.
Project description:Pseudoexfoliation (PEX) is a multifactorial age-related disease involving deposition of extracellular proteinaceous aggregates on anterior ocular tissues. The present study aims to identify functional variants in fibulin-5 (FBLN5) as risk factors for the development of PEX. Thirteen tag single-nucleotide polymorphisms (SNPs) in FBLN5 were genotyped using TaqMan SNP genotyping technology to identify association between SNPs of FBLN5 and PEX in an Indian cohort comprising 200 control and 273 PEX patients (169 PEXS and 104 PEXG). Functional analysis of risk variants was done through luciferase reporter assays and electrophoretic mobility shift assay (EMSA) using human lens epithelial cells. Genetic association and risk haplotype analysis showed a significant association of rs17732466:G>A (NC_000014.9:g.91913280G>A) and rs72705342:C>T (NC_000014.9:g.91890855C>T) within FBLN5 as risk factors with the advanced severe stage of the disease, pseudoexfoliation glaucoma (PEXG). Reporter assays showed allele-specific regulatory effect of rs72705342:C>T on gene expression, wherein, construct containing the risk allele showed a significant decrease in the reporter activity compared with the one with protective allele. EMSA further validated higher binding affinity of the risk variant to nuclear protein. In silico analysis predicted binding sites for two transcription factors, GR-α and TFII-I with risk allele at rs72705342:C>T, which were lost in the presence of protective allele. The EMSA showed probable binding of both these proteins to rs72705342. In conclusion, the present study identified the novel association of two genetic variants in FBLN5 with PEXG but not with PEXS, distinguishing between the early and the later forms of PEX. Further, rs72705342:C>T was found to be a functional variant.
Project description:ObjectivesTo investigate the three single nucleotide polymorphisms (SNPs) (rs3825942, rs1048661, and rs2165241) of the LOXL1 gene in pseudoexfoliation syndrome (XFS) and pseudoexfoliation glucoma (XFG) in the Turkish population.Materials and methodsDNA was obtained from blood samples of 48 XFS, 58 XFG, and 171 control subjects. Three LOXL1 SNPs (rs3825942, rs1048661, rs2165241) were investigated with real time PCR, a probe-based genotyping method, and melting curve analysis.ResultsAll three SNPs of LOXL1 were significantly associated with XFS (rs3825942 p=3.54x10-6, odds ratio [OR]=∞; rs1048661 p=0.008, OR=2.18; rs2165241 p=8.69x10-9, OR=4.30) and XFG (rs3825942 p=3.41x10-7, OR=∞; rs1048661 p=1.75x10-5, OR=3.78; rs2165241 p=3.85x10-11 OR=4.90). No significant differences were observed between the XFS and XFG groups for any of the SNPs. The GG genotype of rs3825942 was more valuable for distinguishing pseudoexfoliative cases from healthy individuals. The homozygous TT genotype of rs2165241 was associated with 6-fold increased XFS risk (p=8.15x10-8, OR=6.32) and 7-fold increased XFG risk (p=1.45x10-10 OR=7.95). The GGT haplotype consisting of all three risk alleles was associated with a 7.45-fold higher risk of XFS/XFG (p=8.65x10-14, OR=7.45). Presence of T allele of rs2165241 conferred 3 times higher risk for men than women (p=6.78x10-5, OR=3.202).ConclusionLOXL1 SNPs are associated with increased risk for pseudoexfoliation in the Turkish population. T allele of rs2165241 was found to be the most important characterized risk factor for our cohort. All SNP distributions were similar to other European and American populations.
Project description:PurposeThree common sequence variants in the lysyl oxidase-like 1 (LOXL1) gene were recently associated with pseudoexfoliation (PEX) and pseudoexfoliation glaucoma (PEXG) in populations from various parts of the world. In this study, the genetic association of these variants was investigated in Greek patients with PEX and PEXG.MethodsThe three LOXL1 single nucleotide polymorphisms (SNPs), one intronic (rs2165241) and two nonsynonymous coding SNPs (rs1048661: R141L and rs3825942: G153D), were genotyped in a total of 48 unrelated patients with PEX, 35 patients with PEXG, and 52 healthy subjects who had normal findings in repeated ophthalmic examinations. A genetic association study was performed.ResultsBetween the two coding SNPs, R141L did not show an association with PEX (p=0.297 for allele G, p=0.339 for genotype GG), whereas allele G of G153D showed a significant association (odds ratio [OR]=3.52, 95% confidence interval [CI]=1.735-7.166, p=3.24×10(-4) for allele G, p=0.004 for genotype GG). Likewise, for the intronic SNP of rs2165241, genotype TT (p=0.005) and its corresponding allele T (OR=2.99, 95% CI=1.625-5.527, p=3.53×10(-4)) showed a significant association with PEX. The allele G of G153D showed a significant association with PEXG (OR=3.74, 95% CI=1.670-8.387, p=0.001). The combined haplotype GGT, consisting of all three risk alleles, was associated with PEX (p=0.037), conferring a 1.8-fold of increased risk to the disease (OR=1.799, 95% CI=1.04-3.13). Furthermore, the haplotype GGT presented in 39.8% of the patients with PEX and 26.9% of the controls.ConclusionsCertain genetic variants in LOXL1 confer risk for PEX in Greek populations, confirming in part findings in patients from Northern Europe.