RIPK3 and RIPK1 gene expression in pterygium: unveiling molecular insights into pathogenesis.

BACKGROUND: Pterygium, characterized by the abnormal proliferation of epithelial cells, matrix remodeling, vascularization, and lesion migration, is a prevalent ocular surface disease involving the growth of fibrovascular tissue on the cornea. Despite the unclear underlying causes of pterygium, numerous investigations have indicated the involvement of cell death pathways in the regulation of cell cycle dynamics. Consequently, the objective of this study was to assess the expression levels of necroptosis markers in individuals diagnosed with pterygium, aiming to shed light on the potential role of necroptosis in the pathogenesis of this condition. METHODS: This study aimed to investigate the expression patterns of receptor-interacting serine/threonine kinase 3 (RIPK3) and receptor-interacting serine/threonine kinase 1 (RIPK1) genes in pterygium tissues. 41 patients undergoing pterygium excision surgery were recruited. Resected pterygium samples and normal conjunctival tissues were collected, and RIPK3 and RIPK1 mRNA levels were measured using quantitative real-time PCR. RESULTS: Our findings reveal that the expression of RIPK3 is significantly increased in samples obtained from individuals with pterygium. However, no significant alterations were observed in the expression of RIPK1 in these samples. Results showed significantly higher RIPK3 expression in pterygium tissues compared to controls. Moreover, increased RIPK3 levels correlated negatively with pterygium recurrence rates. CONCLUSIONS: These findings suggest RIPK3 may play a protective role against pterygium recurrence through necroptosis.

Multi-System-Level Analysis with RNA-Seq on Pterygium Inflammation Discovers Association between Inflammatory Responses, Oxidative Stress, and Oxidative Phosphorylation.

A pterygium is a common conjunctival degeneration and inflammatory condition. It grows onto the corneal surface or limbus, causing blurred vision and cosmetic issues. Ultraviolet is a well-known risk factor for the development of a pterygium, although its pathogenesis remains unclear, with only limited understanding of its hereditary basis. In this study, we collected RNA-seq from both pterygial tissues and conjunctival tissues (as controls) from six patients (a total of twelve biological samples) and retrieved publicly available data, including eight pterygium samples and eight controls. We investigated the intrinsic gene regulatory mechanisms closely linked to the inflammatory reactions of pterygiums and compared Asian (Korea) and the European (Germany) pterygiums using multiple analysis approaches from different perspectives. The increased expression of antioxidant genes in response to oxidative stress and DNA damage implies an association between these factors and pterygium development. Also, our comparative analysis revealed both similarities and differences between Asian and European pterygiums. The decrease in gene expressions involved in the three primary inflammatory signaling pathways-JAK/STAT, MAPK, and NF-kappa B signaling-suggests a connection between pathway dysfunction and pterygium development. We also observed relatively higher activity of autophagy and antioxidants in the Asian group, while the European group exhibited more pronounced stress responses against oxidative stress. These differences could potentially be necessitated by energy-associated pathways, specifically oxidative phosphorylation.

Temperature-dependent autoactivation associated with clinical variability of PDGFRB Asn666 substitutions.

Ocular pterygium-digital keloid dysplasia (OPDKD) presents in childhood with ingrowth of vascularized connective tissue on the cornea leading to severely reduced vision. Later the patients develop keloids on digits but are otherwise healthy. The overgrowth in OPDKD affects body parts that typically have lower temperature than 37°C. We present evidence that OPDKD is associated with a temperature sensitive, activating substitution, p.(Asn666Tyr), in PDGFRB. Phosphorylation levels of PDGFRB and downstream targets were higher in OPDKD fibroblasts at 37°C but were further greatly increased at the average corneal temperature of 32°C. This suggests that the substitution cause significant constitutive autoactivation mainly at lower temperature. In contrast, a different substitution in the same codon, p.(Asn666Ser), is associated with Penttinen type of premature aging syndrome. This devastating condition is characterized by widespread tissue degeneration, including pronounced chronic ulcers and osteolytic resorption in distal limbs. In Penttinen syndrome fibroblasts, equal and high levels of phosphorylated PDGFRB was present at both 32°C and 37°C. This indicates that this substitution causes severe constitutive autoactivation of PDGFRB regardless of temperature. In line with this, most downstream targets were not affected by lower temperature. However, STAT1, important for tissue wasting, did show further increased phosphorylation at 32°C. Temperature-dependent autoactivation offers an explanation to the strikingly different clinical outcomes of substitutions in the Asn666 codon of PDGFRB.

Uncovering the role of transient receptor potential channels in pterygium: a machine learning approach.

OBJECTIVES: We aimed at identifying the role of transient receptor potential (TRP) channels in pterygium. METHODS: Based on microarray data GSE83627 and GSE2513, differentially expressed genes (DEGs) were screened and 20 hub genes were selected. After gene correlation analysis, 5 TRP-related genes were obtained and functional analyses of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed. Multifactor regulatory network including mRNA, microRNAs (miRNAs) and transcription factors (TFs) was constructed. The 5 gene TRP signature for pterygium was validated by multiple machine learning (ML) programs including support vector classifiers (SVC), random forest (RF), and k-nearest neighbors (KNN). Additionally, we outlined the immune microenvironment and analyzed the candidate drugs. Finally, in vitro experiments were performed using human conjunctival epithelial cells (CjECs) to confirm the bioinformatics results. RESULTS: Five TRP-related genes (MCOLN1, MCOLN3, TRPM3, TRPM6, and TRPM8) were validated by ML algorithms. Functional analyses revealed the participation of lysosome and TRP-regulated inflammatory pathways. A comprehensive immune infiltration landscape and TFs-miRNAs-mRNAs network was studied, which indicated several therapeutic targets (LEF1 and hsa-miR-455-3p). Through correlation analysis, MCOLN3 was proposed as the most promising immune-related biomarker. In vitro experiments further verified the reliability of our in silico results and demonstrated that the 5 TRP-related genes could influence the proliferation and proinflammatory signaling in conjunctival tissue contributing to the pathogenesis of pterygium. CONCLUSIONS: Our study suggested that TRP channels played an essential role in the pathogenesis of pterygium. The identified pivotal biomarkers (especially MCOLN3) and pathways provide novel directions for future mechanistic and therapeutic studies for pterygium.

Key Genes of Immunity Associated with Pterygium and Primary Sjögren's Syndrome.

Pterygium and primary Sjögren's Syndrome (pSS) share many similarities in clinical symptoms and ocular pathophysiological changes, but their etiology is unclear. To identify the potential genes and pathways related to immunity, two published datasets, GSE2513 containing pterygium information and GSE176510 containing pSS information, were selected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) of pterygium or pSS patients compared with healthy control conjunctiva, and the common DEGs between them were analyzed. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted for common DEGs. The protein-protein interaction (PPI) network was constructed using the STRING database to find the hub genes, which were verified in clinical samples. There were 14 co-upregulated DEGs. The GO and KEGG analyses showed that these common DEGs were enriched in pathways correlated with virus infection, antigen processing and presentation, nuclear factor-kappa B (NF-κB) and Th17 cell differentiation. The hub genes (IL1R1, ICAM1, IRAK1, S100A9, and S100A8) were selected by PPI construction. In the era of the COVID-19 epidemic, the relationship between virus infection, vaccination, and the incidence of pSS and pterygium growth deserves more attention.

A novel lncRNA lnc-PPRL promotes pterygium development by activating PI3K/PDK1 signaling pathway.

A sight threatening, pterygium is a common proliferative and degenerative disease of the ocular surface. LncRNAs have been widely studied in the occurrence and development of various diseases, however, the study of lncRNAs in pterygium has just relatively lacking. In the present study, we performed the high-throughput RNA sequencing (HTS) technology to identify differentially expressed lncRNAs in pterygium. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were carried out to forecast the regulatory and functional role of lncRNAs in pterygium. Notably, we identified a novel lncRNA, LOC102724238, which we named pterygium positively-related lncRNA (lnc-PPRL), was up-regulated in pterygium. Lnc-PPRL showed to be preferentially accumulated in cytoplasm, and it can promote cell proliferation, migration and invasion of human pterygium epithelium cells (hPECs). Further study of underlying mechanisms demonstrated that lnc-PPRL may exert its biological effect by activating canonical PI3K/PDK1 pathway, and subsequently promoting the activation of Akt/mTOR signaling pathway and its downstream effectors. Interestingly, lnc-PPRL was also proved to influence YAP nuclear localization. Taken together, our study firstly suggested that the "big molecule" lnc-PPRL have potential as a novel therapeutic target for the prevention and treatment of pterygium.

Thrombospondin 1 polymorphism associated with decreased expression and increased risk of pterygium.

PURPOSE: To assess the potential association of a thrombospondin 1 gene (THBS1) single-nucleotide polymorphism (rs1478604) with thrombospondin 1 (TSP-1) mRNA expression, as well as the risk of pterygium, in a pilot study. METHODS: DNA and RNA were isolated from peripheral blood samples collected from normal volunteer subjects (n = 39). In addition, DNA was isolated from conjunctival tissue samples collected during pterygium excision surgeries (n = 42). Relative expression of TSP-1 mRNA was measured by quantitative RT-PCR, and rs1478604 genotype was determined using a TaqMan SNP genotyping assay. Genotype frequencies were compared with mRNA expression and between pterygium samples and normal controls. RESULTS: Expression of TSP-1 mRNA was significantly lower in the peripheral blood of normal subjects who were homozygous for the C allele of rs1478604 (CC) compared to TT and CT genotypes (p = 0.004). When we compared rs1478604 genotypes between normal and pterygium patients, we found that the CC genotype was also associated with an increased risk of pterygium compared to TT (odds ratio (OR) = 5.39, 95% CI [1.26-22.99], p = 0.028), CT (OR = 7.86, 95% CI [1.92-32.17], p = 0.003), and combined CT and TT genotypes (OR = 6.67; 95% CI = [1.75-25.37]; p = 0.003). CONCLUSIONS: We found that the C allele of rs1478604 was associated with both lower TSP-1 expression and higher risk of pterygium, possibly implicating TSP-1 in the pathogenesis of pterygium.

Transcriptome Analysis of Pterygium and Pinguecula Reveals Evidence of Genomic Instability Associated with Chronic Inflammation.

Solar damage due to ultraviolet radiation (UVR) is implicated in the development of two proliferative lesions of the ocular surface: pterygium and pinguecula. Pterygium and pinguecula specimens were collected, along with adjacent healthy conjunctiva specimens. RNA was extracted and sequenced. Pairwise comparisons were made of differentially expressed genes (DEGs). Computational methods were used for analysis. Transcripts from 18,630 genes were identified. Comparison of two subgroups of pterygium specimens uncovered evidence of genomic instability associated with inflammation and the immune response; these changes were also observed in pinguecula, but to a lesser extent. Among the top DEGs were four genes encoding tumor suppressors that were downregulated in pterygium: C10orf90, RARRES1, DMBT1 and SCGB3A1; C10orf90 and RARRES1 were also downregulated in pinguecula. Ingenuity Pathway Analysis overwhelmingly linked DEGs to cancer for both lesions; however, both lesions are clearly still benign, as evidenced by the expression of other genes indicating their well-differentiated and non-invasive character. Pathways for epithelial cell proliferation were identified that distinguish the two lesions, as well as genes encoding specific pathway components. Upregulated DEGs common to both lesions, including KRT9 and TRPV3, provide a further insight into pathophysiology. Our findings suggest that pterygium and pinguecula, while benign lesions, are both on the pathological pathway towards neoplastic transformation.

Activation of LncRNA FOXD2-AS1 by H3K27 acetylation regulates VEGF-A expression by sponging miR-205-5p in recurrent pterygium.

LncRNA FOXD2-AS1 is abnormally expressed in many diseases. However, the molecular mechanisms whereby FOXD2-AS1 is involved in recurrent pterygium remain unknown. Here, qRT-PCR was performed to quantify FOXD2-AS1 expression, while CCK-8, flow cytometer and neoplasm xenograft assays were used to investigate its function. Dual-luciferase reporter, RIP and RNA pull-down assays were conducted to address the relationship between FOXD2-AS1, miR-205-5p and VEGF-A, while ChIP assays were used to detect H3K27 acetylation at the FOXD2-AS1 promoter. FOXD2-AS1 expression was up-regulated in recurrent pterygium tissues. Moreover, a high FOXD2-AS1 expression was associated with advanced stages, increased microvessel density and shorter recurrent-free survival. In addition, ROC analysis showed that FOXD2-AS1 is a valid predictor of recurrent pterygium. Furthermore, we show that FOXD2-AS1 induced proliferation and inhibited apoptosis in a cell line derived from recurrent pterygia (HPF-R) at least partially through the regulation of the miR-205-VEGF pathway. In addition, the up-regulation of FOXD2-AS1 was attributed to the H3K27 acetylation at the promoter region. In conclusion, FOXD2-AS1 is activated via its H3K27 acetylation and regulates VEGF-A expression by sponging miR-205-5p in recurrent pterygium. Our results may provide a basis for the development of new therapeutic targets and biomarkers for recurrent pterygium.

Posttranscriptional regulation of MMP-9 by HuR contributes to IL-1ß-induced pterygium fibroblast migration and invasion.

Inflammation is considered to be critical in the pterygium progression and recurrence. However, the underlying molecular mechanism is not well understood. Herein, we investigated the potential role of RNA binding protein human antigen R (HuR) responsible for the impact of inflammation on pterygium development. The expression of HuR and matrix metallopeptidase-9 (MMP-9) in pterygium and normal conjunctiva was detected with immunohistochemistry and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The influence of interleukin-1ß (IL-1ß) on HuR expression and cellular distribution was determined with western blot and immunofluorescence. The pterygium fibroblast (PTF) migration was determined with scratch wound healing assay and Transwell migration assay. MMP-9 production was determined with qRT-PCR and gelatin zymography. The interaction between HuR and MMP-9 was investigated with RNP immunoprecipitation (IP) followed by RT-PCR and messenger RNA (mRNA) stability analysis. HuR and MMP-9 expression are elevated in pterygium, especially progressive pterygium compared with normal conjunctiva. IL-1ß could increase the expression and nucleus-cytoplasm shuttle of HuR in cultured PTFs. HuR mediated the stimulatory effect of IL-1ß on PTF migration and MMP-9 production. HuR bound to MMP-9 mRNA and in turn increased it stability. Our results suggest that posttranscriptional regulation of MMP-9 via stabilizing mRNA by HuR might contribute to the stimulatory effect of inflammatory factor IL-1ß on pterygium progression. These findings shed light on the pathogenesis of pterygium and provide a promising target for adjuvant treatment of pterygium.

MiR-199a-3p/5p participated in TGF-ß and EGF induced EMT by targeting DUSP5/MAP3K11 in pterygium.

BACKGROUND: Recently, it has been reported that miRNA is involved in pterygium, however the exact underlying mechanism in pterygium is unrevealed and require further investigation. METHODS: The differential expression of miRNA in pterygium was profiled using microarray and validated with quantitative real-time polymerase chain reaction (qRT-PCR). Human conjunctival epithelial cells (HCEs) were cultured and treated with transforming growth factor ß (TGF-ß) and epidermal growth factor (EGF) and transfected with miR-199a-3p/5p mimic and inhibitor. Markers of epithelial-mesenchymal transition (EMT) in HCEs were detected using western blot and immunohistochemistry. Cell migration ability was determined using wound healing and transwell assay, while apoptosis was determined by flow cytometry. The target genes of miR-199a were confirmed by the dual-luciferase reporter assay. RESULTS: TGF-ß and EGF could induced EMT in HCEs and increase miR-199a-3p/5p but suppress target genes, DUSP5 and MAP3K11. With the occurrence of EMT, cell migration ability was enhanced, and apoptosis was impeded. Promoting miR-199a-3p/5p expression could induce EMT in HCEs without TGF-ß and EGF, while suppressing miR-199a-3p/5p could inhibit EMT in TGF-ß and EGF induced HCEs. In a word, TGF-ß and EGF induced EMT could be regulated with miR-199a-3p/5p-DUSP5/MAP3K11 axes. The validated results in tissues showed that, compared with control conjunctival tissues, miR-199a-3p/5p were more overexpressed in pterygium, while DUSP5/MAP3K11 were lower expressed. In addition, bioinformatics analysis indicated the miR-199a-3p/5p-DUSP5/MAP3K11 was belong to MAPK signalling pathway. CONCLUSIONS: TGF-ß and EGF induce EMT of HCEs through miR-199a-3p/5p-DUSP5/MAP3K11 axes, which explains the pathogenesis of EMT in pterygium and may provide new targets for pterygium prevention and therapy.

Immunohistochemical study of STAT3, HIF-1α and VEGF in pterygium and normal conjunctiva: Experimental research and literature review.

Purpose: Signal transducer and activator of transcription 3 (STAT3) is a DNA-binding protein that regulates various biologic processes, including cell growth, apoptosis, and malignant transformation. Abnormal activation of STAT3 is associated with many diseases, and there is currently no relevant study on the pathogenesis of pterygium. The purpose of this study was to investigate the expression and clinical significance of STAT3, HIF-1α, and VEGF in pterygium at different stages. Methods: Immunohistochemistry was used to study the expression levels of STAT3, HIF-1α, and VEGF in 50 cases of pterygium and 20 cases of control conjunctival tissue. The expression intensity of the three proteins was evaluated with Image-Pro Plus 6.0 image analysis software. Results: In the pterygium group, the positive rates for STAT3, HIF-1α, and VEGF were 82.0%, 86.0%, and 84.0%, respectively, while those in the normal conjunctiva group were 40.0%, 25.0%, and 15.0%. The expression of STAT3, HIF-1α, and VEGF in pterygium was higher than that in control conjunctiva, and the expression in advanced pterygium was statistically significantly higher than that in stationary pterygium (p < 0.01). The expression levels of STAT3 and HIF-1α in pterygium were related to the length and depth of the corneal invasion of pterygium. The expression level of VEGF in pterygium was related to the length of pterygium, but not to the depth. In addition, there was a significant positive correlation between the expression of STAT3, HIF-1α, and VEGF (p < 0.01). Conclusions: For the first time, the expression levels of the STAT3, HIF-1α, and VEGF proteins were detected simultaneously in pterygium tissue. Compared with normal conjunctiva, STAT3, HIF-1α, and VEGF were highly expressed in pterygium, and the expression in advanced pterygium tissue was more significant than in the stationary pterygium tissue. It is suggested that STAT3 may directly or through HIF-1α promote VEGF expression and participate in the growth and angiogenesis of pterygium. Targeting STAT3 may provide a new direction for the treatment of pterygium.

Analysis of CRABP2 and FABP5 genes in primary and recurrent pterygium tissues.

The etiology of pterygium remains unclear, but ultraviolet (UV) radiation is generally considered to be major risk factor. Pterygium has similarity features with many cancers, including inflammation, invasion, cell proliferation, anti-apoptosis, angiogenesis and recurrence after resection. Retinoic acid via cellular retinoic acid binding protein 2 (CRABP2) is involved in cell cycle arrest, apoptosis and differentiation, while it via fatty acid binding protein 5 (FABP5) is involved in survival, cell proliferation and angiogenesis, which pathway gets activated depends on the CRABP2/FABP5 ratio. Alterations of retinoid signaling were found in many cancer types. The deregulated retinoid signaling may also contribute to the development and/or recurrence of pterygium. The aim of our study was to determine mRNA and protein expressions of CRABP2 and FABP5 and ratio of CRABP2/FABP5 in primer and recurrent pterygium tissues. Pterygia tissues were collected from 30 eyes of 30 patients undergoing pterygium excision. CRABP2 and FABP5 mRNA and protein expression were assessed using Real-time PCR and Western blotting through examination of excised specimens from pterygium and conjunctiva tissues. The ratio of CRABP2/FABP5 gene expression was not altered when primary pterygium tissues compared normal conjunctival tissues (1.00-fold change). Whereas the ratio of CRABP2/ FABP5 gene expression was decreased when recurrent pterygium tissues compared normal conjunctival tissues (0.81-fold change). Understanding etiopathogenesis of pterygium may aid in the find of more promising treatments to prevent pterygium in earlier stages.

The in vitro anti-fibrotic effect of Pirfenidone on human pterygium fibroblasts is associated with down-regulation of autocrine TGF-ß and MMP-1.

We aimed to investigate the in vitro effect of pirfenidone (PFD) on proliferation, migration and collagen contraction of human pterygium fibroblasts (HPFs). HPFs were obtained from tissue explants during pterygium surgery. After treatment with pirfenidone, the HPFs proliferation was measured by MTT, cell cycle progression measured by flow cytometry, cell migration measured by the scratch assay, and cell contractility evaluated in fibroblast-populated collagen gels. The expression of TGF-ß1, TGF-ß2, MMP-1 and TIMP-1 were also determined with quantitative PCR, western blot and immunofluorescence staining. Results showed pirfenidone markedly inhibited HPFs proliferation with an IC50 of approximately 0.2 mg/ml. After treatment with 0.2 mg/ml pirfenidone for 24 hours, HPFs were at G0/G1 cell cycle arrest, with significantly reduced cell migration capability and collagen contraction, decreased mRNA and protein expressions of TGF-ß1, TGF-ß2 and MMP-1, and no alterations of TIMP-1 expression. Thus, we have concluded that pirfenidone at 0.2 mg/ml inhibits proliferation, migration, and collagen contraction of HPFs, which is associated with decreased expression of TGF-ß and MMP-1, and pirfenidone might represent a potentially therapeutic agent to prevent the recurrence of pterygium after surgery.

The Key Role of VEGF in the Cross Talk between Pterygium and Dry Eye and Its Clinical Significance.

PURPOSE: To examine whether dry eye severity is a risk factor for pterygium activity and whether vascular endothelial growth factor (VEGF) is crucial in the cross talk between pterygium and dry eye. METHODS: A total of 103 patients with primary pterygium (Pteg) were included in the study group; they were divided into 2 groups according to the complication of dry eye (DE) (Pteg + DE group, Pteg - DE group). Further, 60 patients with just dry eye (DE group) and 60 normal individuals (normal) were included as 2 control groups. DE severity and pterygium activity were measured, and unstimulated tear samples and pterygium tissues were collected for cytokine detection. RESULTS: (1) Tear detection: VEGF expression increased in the Pteg + DE group compared to the Pteg - DE, DE, and normal control groups; VEGF was especially increased in the active Pteg + DE group. VEGF concentration was positively correlated with pterygium activity. (2) Tissue detection: the mRNA expression of VEGF was upregulated in the active pterygium group. CONCLUSIONS: Inflammation played an important role in the development of dry eye and pterygium. VEGF was the core molecule in the cross talk, which might explain the high incidence of the coexistence of these 2 diseases.

Analysis of WWOX gene expression and protein levels in pterygium.

PURPOSE: Pterygium, a degenerative and hyperplastic lesion, has premalignant properties as a tumor analog. WWOX is a tumor suppressor gene and involved in many signal pathways, such as cell proliferation, embryonic development, metabolism and apoptosis. In many cancers, the loss of WWOX or the presence of abnormal transcripts indicates the tumor suppressor activity of WWOX. In this study, it was aimed to determine WWOX gene expression and protein levels in pterygium which may be a tumor analog. METHODS: For this purpose, the WWOX gene expression change in 27 pterygium tissue was investigated by real-time PCR method, and the change in WWOX protein was investigated using the Western blot method. RESULTS: According to our results, it was found that the expression and protein levels of WWOX gene in pterygium tissue decreased significantly compared to control tissue (p < 0.05). CONCLUSION: This information indicates that a decrease in expression and protein level in pterygium tissue of WWOX, a tumor suppressor gene, supports claims that pterygium may be a cancer analog tissue.

Signaling roadmap to epithelial-mesenchymal transition in pterygium, TWIST1 centralized.

Pterygium as a complex disease shares common features with other malignant cells in its onset recurrence and especially epithelial-mesenchymal transition (EMT) transition. Although using different approaches including conjunctival autografts, amniotic membrane, radiotherapy, mitomycin C (MMC) has shown promising insights in the inhibition of pterygium recurrence, it needs to be investigated in more details in molecular pathways to present adjuvant target therapy. In this study, we aimed to evaluate the expression of and then illustrate the role of signaling pathways on EMT in pterygium. Using real-time polymerase chain reaction, the twist-related protein 1 (TWIST1) expression was compared in primary pterygium and normal conjunctiva. This study assessed the mRNA expression, as well as the association between the clinicopathological indices and the gene expression level. The expression level of TWIST1 was overexpressed in 36% of our cohort ( n = 76). There was a significant positive correlation between recurrence with grade T, grade V and a significant negative correlation with growth activity. Our vast literature review on different signaling pathways in pterygium showed that EMT has centralization role in recurrence of this disease. Our data confirmed that EMT is important in the recurrence of pterygium samples and different signaling pathways end up activating the EMT markers. It is suggested to evaluate the environmental factors and their correlation with molecular markers to select favorable treatment for this kind of diseases.

Shared gene signature between pterygium and meibomian gland dysfunction uncovered through gene-expression meta-analysis.

BACKGROUND: Pterygium and meibomian gland dysfunction (MGD) are two clinically correlated ocular diseases. We propose to investigate the shared gene signature between pterygium and MGD. METHODS: Microarray datasets were retrieved from the Gene Expression Omnibus (GEO) database. Initial processing of the data was performed using the R programming package. Gene-expression values were log2 transformed and normalized by quantile normalization. The differentially expressed genes (DEGs) in each individual dataset were analyzed by the limma package. The integration of different pterygium datasets and gene-expression meta-analysis was conducted by the NetworkAnalyst package. A Venn diagram was created to find the overlapped DEGs between MGD and pterygium datasets. Gene ontology enrichment and pathway analysis were performed using the ToppGene Suite. RESULTS: We found 193 DEGs significantly up-regulated in pterygium, with the combined effect sizes ranging from 1.53 to 3.78. A gene signature consisting of 11 DEGs were found to be shared by pterygium and MGD (SPRR3, SERPINB13, NMU, KRT10, IL37, KRT6B, PI3, S100A2, MAL, AURKA, and RGCC), and bioinformatics analyses showed that these overlapped DEGs were significantly enriched in pathways related to keratinization, cell-cycle regulation, and formation of the cornified envelope. CONCLUSION: We identified a shared gene signature between pterygium and MGD through gene-expression meta-analysis. The analysis of this signature underlined that keratinization-related pathways may play important roles in the development of these two clinically correlated pathologies.

A novel role for CRIM1 in the corneal response to UV and pterygium development.

Pterygium is a pathological proliferative condition of the ocular surface, characterised by formation of a highly vascularised, fibrous tissue arising from the limbus that invades the central cornea leading to visual disturbance and, if untreated, blindness. Whilst chronic ultraviolet (UV) light exposure plays a major role in its pathogenesis, higher susceptibility to pterygium is observed in some families, suggesting a genetic component. In this study, a Northern Irish family affected by pterygium but reporting little direct exposure to UV was identified carrying a missense variant in CRIM1 NM_016441.2: c.1235 A > C (H412P) through whole-exome sequencing and subsequent analysis. CRIM1 is expressed in the developing eye, adult cornea and conjunctiva, having a role in cell differentiation and migration but also in angiogenesis, all processes involved in pterygium formation. We demonstrate elevated CRIM1 expression in pterygium tissue from additional individual Northern Irish patients compared to unaffected conjunctival controls. UV irradiation of HCE-S cells resulted in an increase in ERK phosphorylation and CRIM1 expression, the latter further elevated by the addition of the MEK1/2 inhibitor, U0126. Conversely, siRNA knockdown of CRIM1 led to decreased UV-induced ERK phosphorylation and increased BCL2 expression. Transient expression of the mutant H412P CRIM1 in corneal epithelial HCE-S cells showed that, unlike wild-type CRIM1, it was unable to reduce the cell proliferation, increased ERK phosphorylation and apoptosis induced through a decrease of BCL2 expression levels. We propose here a series of intracellular events where CRIM1 regulation of the ERK pathway prevents UV-induced cell proliferation and may play an important role in the in the pathogenesis of pterygium.

Assessment of miR-182, miR-183, miR-184, and miR-221 Expressions in Primary Pterygium and Comparison With the Normal Conjunctiva.

OBJECTIVES: The aim of this study was to investigate the expression levels of miR-126-3p, miR-182-5p, miR-183-5p, miR-184, miR-221-3p, and miR-205-5p in primary pterygium tissue and compare these levels with those in healthy conjunctiva tissue. METHODS: Twenty-four patients who were diagnosed with grade 3 primary pterygium and scheduled for surgery between January 2014 and January 2016 and had no systemic disease or other ocular pathology were included in the study. The control group comprised nasal interpalpebral conjunctival tissue specimens from 24 age- and sex-matched patients with no history of systemic disease or ocular pathology other than cataract. Expression levels of miR-126-3p, miR-182-5p, miR-183-5p, miR-184, miR-221-3p, and miR-205-5p were determined and compared between the pterygium and conjunctiva specimens. RESULTS: Expression levels of miR-182-5p, miR-183-5p, and miR-184 were significantly higher in pterygium tissue compared with normal conjunctival specimens (P<0.0001, P=0.01, and P=0.01, respectively), whereas expression of miR-221-3p was significantly lower (P=0.02). Expression levels of miR-126-3p and miR-205-5p did not differ significantly between the 2 groups (P>0.05). CONCLUSIONS: Expression levels of miR-182-5p, miR-183-5p, and miR-184 are increased, whereas expression of miR-221-3p is decreased in primary pterygium tissue, and these miRNAs may play a role in the pathogenesis of pterygium.