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Background: Single nucleotide polymorphisms (SNPs), as the most abundant form of DNA variation in the human genome, contribute to age-related cataracts (ARC) development. Apoptosis of lens epithelial cells (LECs) is closely related to ARC formation. Insulin-like growth factor 1 (IGF1) contributes to cell apoptosis regulation. Moreover, IGF1 was indicated to exhibit a close association with cataract formation. Afterward, an investigation was conducted to examine the correlation between polymorphisms in IGF1 and the susceptibility to ARC., Methods: The present investigation was a case-control study. Venous blood draws were collected from the participants for DNA genotyping. Lens capsule samples were collected to detect mRNA and apoptosis. TaqMan RT-PCR was used to detect IGF1 polymorphism genotypes and qRT PCR was used to detect IGF1 mRNA levels in LECs. LEC apoptosis was evaluated through flow cytometry. The chi-square test was used to compare differences between ARCs and controls of each SNP., Results: We found that the G allele frequency in the IGF1 -rs6218 was higher in the ARCs than in the controls. Furthermore, it was observed that the rs6218 GG genotype exhibited a positive correlation to elevated levels of IGF1 mRNA in LECs. The IGF1 mRNA in the LECs and the apoptosis of LECs in nuclear type of ARCs (ARNC) was higher than the controls., Conclusion: The susceptibility to ARC was related to IGF1 -rs6218 polymorphism, and this polymorphism is associated with IGF1 expression at the mRNA level. Moreover, apoptosis in LECs of ARNCs was found to be increased., Competing Interests: The authors declare that they have no competing interests., (© 2024 Zou et al.)

Background: In the present study, we explored the role of N 6 -methyladenosine (m 6 A) modification of long non-coding RNAs (lncRNAs) and its association with ferroptosis in lens epithelium cells (LECs) of age-related cataract (ARC)., Methods: Through m 6 A RNA immunoprecipitation sequencing (m 6 A-RIP-seq) and RNA sequencing (RNA-seq), we identified m 6 A mediated and differentially expressed lncRNAs (dme-lncRNAs) in ARC patients. Based on bioinformatics analysis, we selected critical dme-lncRNAs and pathways associated with ARC formation to reveal their potential molecular mechanisms. The downregulation of glutathione peroxidase 4 (GPX4), a key component of ferroptosis, was confirmed by real-time RT-PCR (RT-qPCR) and Western blotting in age-related cortical cataract (ARCC) samples. Transmission electron microscopy was used to assess the change in mitochondrial in LECs., Results: The analysis revealed a total of 11,193 m 6 A peaks within lncRNAs, among which 7043 were enriched and 4150 were depleted. Among those, lncRNA ENST00000586817(upstream of the GPX4 gene) was not only significantly upregulated in the LECs of ARCC but also potentially augmented the expression of GPX4 through a cis mechanism. The expression of m 6 A-modified lncRNA (ENST00000586817) was correlated with that of GPX4 and was downregulated in ARC patients. The TEM results indicated significant mitochondrial changes in ARCC samples. GPX4 downregulation enhanced LEC ferroptosis and decreased viability via RSL3 in SRA01/04 cells., Conclusions: Our results provide insight into the potential function of m 6 A-modified lncRNAs. M 6 A-modified lncRNA ENST00000586817 might regulate the expression of GPX4 by a cis mechanism and be implicated in ferroptosis in ARCs., (© 2023. The Author(s).)

Ultraviolet B (UVB) irradiation could trigger DNA double-strand breaks (DDSBs) and senescence in lens epithelial cells (LECs), thus inducing age-related cortical cataract (ARCC) formation. Cell-cycle irreversible arrest induced by DDSBs depended on excessive activation of ataxia-telangiectasia mutated kinase (ATM). We studied the up-regulated circular RNA circMRE11A_013 (circMRE11A) in LECs of ARCC and SRA01/04 cell lines under UVB exposure. In vitro , knockdown of circMRE11A in SRA01/04 cell lines enhanced cell viability and cell cycle, while over-expression of circMRE11A exhibited an opposite trend. Additionally, circMRE11A could bind to UBX domain-containing protein 1 (UBXN1), which might enhance excessive activation of ATM and initiate ATM/p53/p21 signaling pathway causing LECs cell-cycle arrest and senescence. In vivo , recombinant adeno-associated virus vectors (rAAV-2) virions of circMRE11A (circMRE11A-AAV2) was injected to Institute of Cancer Research mouse vitreous cavity. The circMRE11A-AAV2 could express in mouse lens at 4 weeks. The LECs aging and opacity lens were observed at 8 weeks after the injection. Together, our findings reveal a previously unidentified role of circMRE11A interacting with UBXN1 in enhancing ATM activity and inhibiting LECs cell-cycle in ARCC formation. The findings might give us a better understanding of ARC pathology and provide a novel and more effective therapeutic approaches for ARC treatment.

Research showed that lanosterol can decrease protein aggregation in lens and reduce cataract formation. Lanosterol synthase (LSS) and 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) are the limiting enzymes in the process of synthesis of lanosterol. We demonstrate to investigate the association between functional single-nucleotide polymorphisms (SNPs) of LSS and HMGCR genes and age-related cataract (ARC) risks in Han Chinese population from Jiangsu Eye Study. This is a case-control study. We collected participants' venous blood for DNA genotyping and lens capsule samples for RNA. The SNPs of the genes were assayed with TaqMan RT-PCR genotyping. The quantitative RT-PCR was used to detect the LSS mRNA levels of lens epithelial cells (LECs) in individuals. The chi-square test was used to compare differences between ARC groups and controls of each SNP and to calculate the odds ratio (OR). We found that LSS -rs2968 of ARCs was different from controls ( p  = 0.018), but the significance was lost after Bonferroni correction ( p  = 0.072). We then further performed stratification analysis and found that LSS -rs2968 A allele was associated with nuclear type of ARC risk in Chinese population ( p  = 0.012, OR = 0.68). Consequently, we found that the mRNA expression of LSS was lower in LECs of all subtypes of ARC group than that of control group ( p  < 0.05). LSS -rs2968 A allele might play a role in the formation and development of nuclear type of ARC risk in Chinese population.

Purpose: To explore the involvement of N6-methyladenosine (m6A) modification in circular RNAs (circRNAs) and relevant methyltransferases in the lesion of lens epithelium cells (LECs) under the circumstances of age-related cataract (ARC)., Methods: LECs were collected from normal subjects and patients with cortical type of ARC (ARCC). M6A-tagged circRNAs and circRNAs expression were analyzed by m6A-modified RNA immunoprecipitation sequencing (m6A-RIP-seq) and RNA sequencing (RNA-seq). Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used to predict possible functions of the m6A-circRNAs. Expression of m6A-related methyltransferase and demethytransferase was measured by quantitative real-time polymerase chain reaction. Expression and location of AlkB homolog 5 RNA demethylase (ALKBH5), a key component of m6A demethytransferase, were determined by Western blot and immunostaining., Results: All 4646 m6A peaks within circRNAs had different abundances, with 2472 enriched and 2174 subdued. The level of m6A abundance in total circRNAs was decreased in the LECs from ARCCs in comparison with the controls. We also found that the expression of highly m6A-tagged circRNAs was mostly decreased in comparison with non-m6A-tagged circRNAs. The bioinformatics analysis predicted the potential functions of m6A modified circRNAs and the relevant pathways that may be associated with m6A modified circRNAs. Among five major methyltransferases, ALKBH5 was significantly upregulated in LECs of ARCCs., Conclusions: Our data provided novel evidence regarding the involvement of circRNAs m6A modifications in ARC. The altered expression of methyltransferases in lens tissue might selectively change the epigenetic profile of lens genome through regulating genes that host the circRNAs, thus enhance the susceptibility to ARC. The results might provide a new insight in the molecular target of ARC pathogenesis.

DNA damage in lens cells is considered a critical trigger for the onset of age-related cataracts (ARCs). Among DNA repair pathways, the base excision repair (BER) pathway is responsible for mending single-strand breaks in DNA. In this case-control study with 993 ARC cases and 993 healthy controls, we genotyped 9 single-nucleotide polymorphisms (SNPs) within microRNA (miRNA) regions of 6 BER pathway genes and examined their associations with ARC susceptibility. We identified rs4639:T > C in the Nei-like DNA glycosylase 2 ( NEIL2 ) gene as significantly associated with ARCs. Individuals carrying different rs4639 alleles had distinct NEIL2 expression in lens capsule tissues from ARC cases and controls. Bioinformatics predicts that the rs4639 T allele could disrupt hsa-miR-3912-5p binding. The results of the luciferase reporter assay were in concordance with this prediction. This study has added more evidence that SNP-modified posttranscriptional gene regulation by miRNA might be a potential pathogenic mechanism of ARCs. SNPs potentially affecting miRNA binding to the 3'UTR of BER pathway genes could contribute to discrepant disease susceptibility. NEIL2 -rs4639T was strongly associated with a protective role in ARCs. This protective role might be fulfilled by maintaining normal expression of NEIL2 in the mediation of disrupted binding of rs4639T with hsa-miR-3912-5p. A further study to generate model systems (cell lines or animal models) with NEIL2 variants is warranted. The results provide 2 molecular targets ( e.g. , NEIL2 and hsa-miR-3912-5p) for intervention strategies of ARC in the future.-Kang, L., Zou, X., Zhang, G., Xiang, J., Wang, Y., Yang, M., Chen, X., Wu, J., Guan, H. A variant in a microRNA binding site in NEIL2 3'UTR confers susceptibility to age-related cataract.

DNA oxidative damage repair is strongly involved in the pathogenesis of age-related cataract (ARC). The sequence variants of in coding region of DNA repair genes have been shown to be associated with ARC. It is known that single nucleotide polymorphisms (SNPs) in the 3'-terminal untranslated region (3'-UTR) can alter the gene expression by binding with microRNAs (miRNAs). We hypothesize that SNP(s) in miRNA binding site of certain DNA oxidative damage repair genes might associate with ARC risk. We examined 10 miRNA binding SNPs in 3'-UTR of 7 oxidative damage genes and revealed the XPC- rs2229090 C allele was associated with nuclear type of ARC (ARNC) risk in Chinese population. The individuals with the variant G allele (CG and GG) of XPC- rs2229090 had higher XPC mRNA expression compared to individuals carrying CC genotype. The in vitro assay showed that luciferase reporter gene expression can be down regulated by hsa-miR-589-5p in cells transfected with rs2229090 C allele compared to G allele. These results suggested that the C allele of XPC-2229090 increase the risk with ARNC. The mechanism underlying might be due to the stronger interation of the C allele with hsa-miR-589-5p, resulting in lower XPC expression and DNA repair capability than the individuals carring G allele in lens.

Background: In the present study, we explored the role of N6-methyladenosine (m6A) modification of long non-coding RNAs (lncRNAs) and its association with ferroptosis in lens epithelium cells (LECs) of age-related cataract (ARC). Methods: Through m6A RNA immunoprecipitation sequencing (m6A-RIP-seq) and RNA sequencing (RNA-seq), we identified m6A mediated and differentially expressed lncRNAs (dme-lncRNAs) in ARC patients. Based on bioinformatics analysis, we selected critical dme-lncRNAs and pathways associated with ARC formation to reveal their potential molecular mechanisms. The downregulation of glutathione peroxidase 4 (GPX4), a key component of ferroptosis, was confirmed by real-time RT-PCR (RT-qPCR) and Western blotting in age-related cortical cataract (ARCC) samples. Transmission electron microscopy was used to assess the change in mitochondrial in LECs. Results: The analysis revealed a total of 11,193 m6A peaks within lncRNAs, among which 7043 were enriched and 4150 were depleted. Among those, lncRNA ENST00000586817(upstream of the GPX4 gene) was not only significantly upregulated in the LECs of ARCC but also potentially augmented the expression of GPX4 through a cis mechanism. The expression of m6A-modified lncRNA (ENST00000586817) was correlated with that of GPX4 and was downregulated in ARC patients. The TEM results indicated significant mitochondrial changes in ARCC samples. GPX4 downregulation enhanced LEC ferroptosis and decreased viability via RSL3 in SRA01/04 cells. Conclusions: Our results provide insight into the potential function of m6A-modified lncRNAs. M6A-modified lncRNA ENST00000586817 might regulate the expression of GPX4 by a cis mechanism and be implicated in ferroptosis in ARCs. [ABSTRACT FROM AUTHOR]