High-expression of ROCK1 modulates the apoptosis of lens epithelial cells in age-related cataracts by targeting p53 gene

APEX1 attenuates ERS-induced paraptosis by inhibiting the P53 pathway in LECs

Age-related cortical cataract (ARCC) is a prominent subtype of cataract, characterized by the presence of vacuoles and spoke-like opacity. Previous studies have suggested that paraptosis is involved in the onset of early ARCC vacuolar degeneration. In this experiment, hydrogen peroxide (H2O2)-induced SRA01/04 cells were used to establish a paraptosis-like cell model, and the function and underlying mechanism of APEX1 in this cell model were explored. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western Blot analyses were conducted to assess the expression of pertinent genes in SRA01/04. Confocal fluorescence microscopy, using ER-tracker kits, was applied to clarify the relationship between the endoplasmic reticulum and intracellular vacuoles. The co-IP assay was used to verify the interaction between APEX1 and P53. The GTRD database was employed to predict the putative target genes combined with P53, and CUT&RUN assay was employed to confirm the enrichment of the P53 and ATF6 promoters following APEX1 overexpression. Firstly, the pathological sections of the vacuolar degeneration zone in the lens cortex of ARCC patients exhibited fiber disarray and vacuole development. Meanwhile, the protein expression of Alix, a specific paraptosis inhibitor, was decreased in low-concentration H2O2-treated SRA01/04 cells. Secondly, we discovered that 4-PBA suppressed the expression of ATF6 and PERK. Moreover, overexpression of APEX1 in SRA01/04 cells improved endoplasmic reticulum morphology, inhibited the interaction between P53 and ATF6, and attenuated paraptosis in SRA01/04. APEX1 regulated P53 and then mediated ATF6 to affect the endoplasmic reticulum stress and paraptosis in H2O2-induced SRA01/04 cells.

HUWE1-mediated ubiquitination and degradation of oxidative damage repair gene ATM maintains mitochondrial quality control system in lens epithelial cells

Mitochondrial dysfunction, resulting from a diminished oxidative damage repair capacity of mitochondrial DNA (mtDNA) in peripheral lens epithelial cells (LECs), is a key pathogenic mechanism in age-related cortical cataract (ARCC). This study aims to investigate the potential role of the E3 ligase HUWE1 and its ubiquitination substrate, the oxidative damage repair gene ATM, in the pathogenesis of ARCC. Our findings reveal that ATM protein expression is downregulated in human peripheral lens epithelial cells and the turbid cortex, correlating with increased expression of HUWE1. Overexpression of ATM is shown to repair damaged mtDNA, protect mitochondria in LECs from oxidative damage, inhibit mitochondrial fission, enhance mitochondrial biogenesis and mitophagy, and prevent LECs apoptosis. Conversely, overexpression of HUWE1 may negate the protective effects of ATM via the ubiquitination pathway, promote oxidative stress-induced mitochondrial damage, increase the expression of mitochondrial fission proteins Drp1/Fis1, lead to mitochondrial network fragmentation and LECs apoptosis. In a SD rat lens model ex vitro, the ATM inhibitor AZD0156 exacerbated lens opacity, whereas the mitochondrial fission inhibitor Mdivi-1 restored lens transparency. These results suggest that modulating key molecules involved in oxidative damage repair and mitochondrial fission pathways could enhance mitochondrial quality control, paving the way for the development of targeted molecular therapies for the prevention and treatment of ARCC.

Crosstalk between signaling pathways (Rho/ROCK, TGF-β and Wnt/β-Catenin Pathways/ PI3K-AKT-mTOR) in Cataract: A Mechanistic Exploration and therapeutic strategy

Cataract are a leading cause of visual impairment that is characterized by clouding or lens opacification of the healthy clear lens of the eye or its capsule. It can be classified based on their etiology and clinical presentation such as congenital, age-related, and secondary cataracts. Clinically, it may be further classified as a cortical or nuclear cataract. Cortical cataracts are responsible for opacification of the lens cortex, while nuclear cataracts cause age-related degeneration of the lens nucleus. This review aims to explore the molecular mechanism associated with various signaling pathways underlying cataract formation. Additionally, explore the potential therapeutic strategies for the management of cataracts. A comprehensive literature search was performed utilizing different keywords such as cataract, pathogenesis, signaling pathways, therapeutic approaches, RNA therapeutics, and surgery. Electronic databases such as PubMed, Google Scholar, Springer Link, and Web of Science were used for the literature search. The cataract formation is responsible for protein aggregation, primarily of γ-crystallin, and causes disruptions in signaling pathways. Key pathways include Rho/ROCK, TGF-β, Wnt/β-catenin, NF-κB, and PI3K-AKT-mTOR. Signaling pathways governing lens epithelial cell differentiation and epithelial-to-mesenchymal transition (EMT) are essential for maintaining lens transparency. Disruptions in these pathways, often caused by genetic mutations in genes like MIP, TDRD7, PAX6, FOXE3, HSF4, MAF, and PITX3 lead to cataract formation. While surgical intervention remains the primary treatment, pharmacological therapies and emerging RNA-based strategies offer promising strategies for the prevention and management of cataracts. A deeper understanding of the underlying molecular mechanisms is essential to develop innovative therapeutic strategies and improve the quality of life for individuals affected by cataracts.

Sagittaria sagittifolia polysaccharide extract regulates Nrf2 to improve endoplasmic reticulum stress-mediated apoptosis in rat cataracts and HLEB3 cells

Age-related cataract (ARC) remains the leading cause of blindness worldwide. Sagittaria sagittifolia polysaccharide (SSP) extract, a key component of Sagittaria sagittifolia L., exhibits anti-oxidant and anti-apoptotic effects with potential applications in ARC. This study aimed to explore the therapeutic potential of SSP in ARC and the underlying mechanisms. In sodium selenite-induced cataracts in rats and hydrogen peroxide (H2O2)-induced human lens epithelial B3 (HLEB3) cells, SSP significantly improved lens opacity and pathological changes and alleviated apoptosis and endoplasmic reticulum stress (ERS)-related injury indicators (by inhibiting the intracellular Ca2+ and protein expression of Bcl-2-associated X, cleaved caspase-3, binding immunoglobulin heavy chain protein, protein kinase RNA-like kinase, inositol-requiring enzyme 1α, activating transcription factor 6, C/EBP homology protein, c-Jun N terminal kinase, caspase-12, and calpain-2). In addition, SSP increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1, sarco/endoplasmic reticulum-type calcium transport ATPase 2, and B-cell lymphoma-2. After applying Nrf2 knockdown technology by transferring short interfering RNA in HLEB3 cells, SSP demonstrated its protective role by activating Nrf2 and inhibiting ERS-mediated apoptosis. These findings indicate that SSP may protect against ARC by regulating Nrf2/ERS-mediated apoptosis, providing potential evidence for its use in preventing or delaying ARC.

Sirtuin 1 Suppresses Hydrogen Peroxide-Induced Senescence and Promotes Viability and Migration in Lens Epithelial Cells by Inhibiting Forkhead Box Protein O1/Toll-Like Receptor 4 Pathway

Age-related cataracts (ARCs) are associated with increased oxidative stress and cellular senescence. Our objective is to investigate the function of Sirtuin 1 (SIRT1) within ARCs. In ARCs tissues and H2O2-treated lens epithelial cells (LECs), the expression levels of SIRT1 were examined. Senescence-associated β-galactosidase (SA-β-gal) staining was employed to evaluate cellular senescence. The Cell Counting Kit-8 assay was employed to measure viability. A wound healing assay was performed to assess migratory capacity in LECs. Oxidative stress-related indicators were determined by enzyme-linked immunosorbent assay kits. Additionally, the Coxpresdb and GeneCards databases were utilized to identify downstream pathways of SIRT1 in ARCs. The expression levels of protein and mRNA were detected using western blot and real-time quantitative polymerase chain reaction, respectively. The expression of SIRT1 was downregulated in ARCs tissues with an increase in reactive oxygen species. In H2O2-induced LECs, SIRT1 was downregulated and its overexpression inhibited oxidative stress and cellular senescence while promoting viability and migration. Furthermore, FoxO1/TLR4 pathway was screened out as the key pathway of SIRT1, which was activated in H2O2-induced LECs senescence. Overexpression of SIRT1 suppressed FoxO1/TLR4 pathway. Further research demonstrated that the activation of FoxO1/TLR4 pathway reversed the inhibitory role of SIRT1 in oxidative stress-induced cellular senescence and the promotion effect of SIRT1 on viability and migration in H2O2-induced LECs. SIRT1 inhibits oxidative stress-induced cellular senescence and promotes the viability and migration in H2O2-induced LECs via suppressing FoxO1/TLR4 pathway.

Targeted Activation of OGG1 Inhibits Paraptosis in Lens Epithelial Cells of Early Age-Related Cortical Cataract

Purpose

To investigate potential modes of programmed cell death in the lens epithelial cells (LECs) of patients with early age-related cortical cataract (ARCC) and to explore early-stage intervention strategies.

Methods

Anterior lens capsules were collected from early ARCC patients for comprehensive analysis. Ultrastructural examination of LECs was performed using transmission electron microscopy. Cell death-associated protein markers were quantified via Western blot analysis, including those for paraptosis (ALIX, GRP78), apoptosis (cleaved caspase 3 and caspase 9), pyroptosis (N-GSDMD), and ferroptosis (GPX4). Intracellular vesicle-organelle colocalization was assessed through immunofluorescence. OGG1 protein expression and activity were evaluated through multiple methods, including Western blot, laser micro-irradiation, and immunofluorescence. The therapeutic potential of the OGG1 activator TH10785 on paraptosis was investigated using an ex vivo rat lens model.

Results

Morphologic changes revealed significant endoplasmic reticulum (ER) swelling in ARCC patient LECs, with no characteristic apoptotic features. Paraptosis-related proteins exhibited significant alterations, while other cell death pathway markers (apoptosis, pyroptosis, and ferroptosis) remained unchanged. In the reactive oxygen species-induced paraptosis model, vesicular structures showed exclusive colocalization with ER-specific fluorescence. Elevated levels of the DNA damage marker 7,8-dihydro-8-oxoguanine were observed concurrent with decreased OGG1 activity. The OGG1 activator TH10785 showed efficacy in suppressing LECs paraptosis in ex vivo rat lens cultures.

Conclusions

Paraptosis was identified in the LECs of patients with early ARCC. TH10785 activates OGG1 to suppress paraptosis in LECs, suggesting a novel therapeutic approach for early ARCC intervention.

Low-level PM2.5 induces the occurrence of early pulmonary injury by regulating circ_0092363

The significant correlation between particulate matter with aerodynamic diameters of ≤ 2.5 µm (PM2.5) and the high morbidity and mortality of respiratory diseases has become the consensus of the research. Epidemiological studies have clearly pointed out that there is no safe concentration of PM2.5, and mechanism studies have also shown that exposure to PM2.5 will first cause pulmonary inflammation. Therefore, the purpose of this study is to explore the mechanism of early lung injury induced by low-level PM2.5 from the perspective of epigenetics. Based on the previous results of population samples, combined with an in vitro/vivo exposure model of PM2.5, it was found that low-level PM2.5 promoted the transport of circ_0092363 from intracellular to extracellular spaces. The decreased expression of intracellular circ_0092363 resulted in reduced absorption of miR-31-5p, leading to inhibition of Rho associated coiled-coil containing protein kinase 1 (ROCK1) and the subsequent abnormal expression of tight junction proteins such as Zonula occludens protein 1 (ZO-1) and Claudin-1, ultimately inducing the occurrence of early pulmonary injury. Furthermore, this study innovatively introduced organoid technology and conducted a preliminary exploration for a study of the relationship among environmental exposure genomics, epigenetics and disease genomics in organoids. The role of circ_0092363 in early pulmonary injury induced by low-level PM2.5 was elucidated, and its value as a potential diagnostic biomarker was confirmed.

Baicalein improves Na2SeO3 induced cataract by enhancing the antioxidant capacity of juvenile Sprague Dawley Rat

ETHNOPHARMACOLOGICAL RELEVANCE

Baicalein (BAI) is the crucial flavonoid component in Scutellaria baicalensis Georgi, possessing biological functions such as anti-oxidant, anti-apoptotic, and anti-inflammatory. However, there is limited intensive pharmacological and mechanistic research on the therapeutic effects of BAI for cataract treatment.

AIM OF THE STUDY

This study aimed to investigate the effects and mechanisms of BAI on Na2SeO3-induced cataract in juvenile rats.

MATERIALS AND METHODS

The cataract model was established by a single subcutaneous injection of 3.46 mg/kg Na2SeO3 on the back of 10-day-old rats. The BAI (25 mg/kg, 50 mg/kg, 100 mg/kg) was administered to the 8-day-old rats and continued until they reached 30 days of age, and the opacity of the lens was observed using a slit lamp microscope every 3 days. Pathological changes in the lens were observed using hematoxylin-eosin (HE) staining to investigate the effects of BAI on Na2SeO3-induced cataract in rats. The levels of antioxidant substances in rat serum and the lens, as well as the levels of soluble and insoluble proteins in rat lens, were measured by the reagent kit. Furthermore, the mechanism of BAI on Na2SeO3-induced cataract rats was analyzed by network pharmacology, molecular docking, and Western blot.

RESULTS

BAI significantly increased the content of soluble proteins in the lens, mitigated the dense opacity of rat lens and reduced the damage to lens epithelial cells, reduced the levels of malondialdehyde (MDA) in rat serum and lens, increased the levels of total superoxide dismutase (T-SOD) and Glutathione peroxidase (GSH-PX). The improvement effects of BAI on Na2SeO3-induced cataract may related to the mitogen-activated protein kinase (MAPK) and the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways.

CONCLUSION

In conclusion, this study demonstrated that BAI could mitigate the dense opacity of rat lens in Na2SeO3-induced cataract rats, which may be achieved through the MAPK signaling pathway and the PI3K/AKT signaling pathway.

Scinderin Promotes Hydrogen Peroxide-induced Lens Epithelial Cell Injury in Age-related Cataract

BACKGROUND

Scinderin (SCIN) is a calcium-dependent protein implicated in cell growth and apoptosis by regulating actin cleavage and capping. In this study, we investigated the role of SCIN in hydrogen peroxide-induced lens epithelial cell (LEC) injury related to age-related cataract (ARC).

METHODS

Anterior lens capsules from ARC patients were collected to examine SCIN expression levels. Immortalized human LEC cell line SRA01/04 and lens capsules freshly isolated from mice were induced by H2O2 to mimic the oxidative stress in ARC. The role of SCIN was investigated by gain-of-function (overexpression) and loss-offunction (knockdown) experiments. Flow cytometry (FCM) and Western-blot (WB) assays were performed to investigate the effect of SCIN on apoptosis. The oxidative stress (OS) was examined by detecting malondialdehyde (MDA) level, superoxide dismutase (SOD) and catalase (CAT) activity. The interaction between SCIN mRNA and miR-489-3p was predicted by StarBase and miRDB databases and validated by luciferase reporter activity assay.

RESULTS

SCIN was significantly elevated in cataract samples, and the expression levels were positively correlated with the nuclear sclerosis grades. SCIN overexpression promoted OS and apoptosis in H2O2-induced SRA01/04 cells, while SCIN silencing showed the opposite effect. We further showed that miR-489-3p was a negative regulator of SCIN. miR-489-3p overexpression suppressed apoptosis and OS in H2O2-induced SRA01/04 cells by targeting SCIN.

CONCLUSION

Our study identified SCIN as an upregulated gene in ARC, which is negatively regulated by miR-489-3p. Targeting miR-489-3p/SCIN axis could attenuate OS-induced apoptosis in LECs.

Sestrin 2 protects human lens epithelial cells from oxidative stress and apoptosis induced by hydrogen peroxide by regulating the mTOR/Nrf2 pathway

OBJECTIVE

We aimed to explore the effect and potential mechanism of Sestrin 2 (SESN2) in human lens epithelial cells (HLECs).

METHODS

To mimic the oxidative stress environment, SAR01/04 cells were treated with 200 μM hydrogen peroxide (H2O2) for 24 h. Cell viability and apoptosis were checked by cell counting kit-8 and flow cytometry. Western blot was taken to check the protein changes of SESN2, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), mechanistic target of rapamycin (mTOR), phosphorylated (p)-mTOR, ribosomal protein S6 kinase B1 (p70S6K), p-p70S6K, and nuclear factor erythroid 2-related factor 2 (Nrf2). Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and reactive oxygen species (ROS) were detected via the corresponding reagent kit. The levels of interleukin (IL)-1β, IL-18, and tumor necrosis factor (TNF)-α were measured using enzyme-linked immunosorbent assay.

RESULTS

SESN2 was down-regulated in cataract lens tissue and up-regulated in SAR01/04 cells treated with H2O2. Under treatment of H2O2, up-regulation of SESN2 improved cell viability, enhanced the activity of SOD and CAT, inhibited cell apoptosis, and reduced the levels of MDA, ROS, IL-1β, IL-18, and TNF-α, while down-regulation of SESN2 caused the contrary effects. Further bioinformatics analysis suggested that SESN2 regulated the mTOR signaling pathway. Treatment of H2O2 inhibited p-mTOR and p-p70S6K protein expression, while overexpression of SESN2 increased p-mTOR and p-p70S6K protein expression in the H2O2 group and down-regulation of SESN2 further decreased p-mTOR and p-p70S6K protein expression in the H2O2 group. Additionally, H2O2 increased Nrf2 protein expression, and overexpression of SESN2 further increased Nrf2 protein expression in the H2O2 group. Importantly, rapamycin (an inhibitor of mTOR signaling pathway) and knockdown of Nrf2 reversed the promotive effects of SESN2 on cell viability and the inhibitive effects of SESN2 on cell apoptosis, oxidative stress, and inflammatory reaction.

CONCLUSION

SESN2 protected HLECs damage induced by H2O2, which was related to the activation of mTOR/Nrf2 pathway.

Epigallocatechin gallate delays age-related cataract development via the RASSF2/AKT pathway

Age-related cataract (ARC) is a common eye disease, the main cause of which is oxidative stress-mediated apoptosis of lens epithelial cells (LECs). Epigallocatechin gallate (EGCG) is the most potent antioxidant in green tea. Our results demonstrated that EGCG could effectively reduce apoptosis of LECs and retard lens clouding in aged mice. By comparing transcriptome sequencing results of three groups of mice (young control, untreated aged, and EGCG-treated) and screening using GO and KEGG analyses, we selected RASSF2 as the effector gene of EGCG for mechanistic exploration. We verified that the differential expression of RASSF2 was associated with the occurrence of ARC in clinical samples and mouse tissues by immunohistochemistry and western blotting, respectively. We showed that high RASSF2 expression plays a crucial role in the oxidative induction of apoptosis in LECs, as revealed by overexpression and interference experiments. Further studies showed that RASSF2 mediates the inhibitory effect of EGCG on apoptosis and ARCogenesis in LECs by regulating AKT (Ser473) phosphorylation. In this study, we found for the first time the retarding effect of EGCG on lens clouding in mice and revealed the mechanism of action of RASSF2/AKT in it, which provides a theoretical basis for the targeted treatment of EGCG.

Upregulation of EphA2 is associated with apoptosis in response to H2O2 and UV radiation-induced cataracts

In this article, we examine the role of erythropoietin-producing hepatocellular receptor A2 (EphA2) in the apoptosis of lens epithelial cells (LECs) in H2O2 and UV radiation-induced cataracts. We treated SRA01/04 cells with H2O2 or ultraviolet (UV) radiation to create a cataract cell model. We constructed a cataract lens model by exposing mice to UV radiation. We used CCK8 assays, Annexin V-FITC analysis, and immunohistochemical staining to explore proliferation and apoptosis of the cataract model. Thereafter, we used quantitative real-time PCR (qPCR) analysis, Western blot assays, and immunofluorescence to determine gene and protein expression levels. We also employed Crispr/Cas9 gene editing to create an EphA2 knockout in SRA01/04 cells. Results: H2O2 or UV radiation induced SRA01/04 cells showed EphA2 gene upregulation. CCK8 and apoptosis assays showed that EphA2 over-expression (OE) reduced epithelial cell apoptosis, but knockout of EphA2 induced it in response to H2O2 and UV radiation, respectively. Mutation of the EphA2 protein kinase domain (c.2003G > A, p. G668D) had a limited effect on cell apoptosis. In vivo, the EphA2 protein level increased in the lenses of UV-treated mice. Our results showed that EphA2 was upregulated in SRA01/04 cells in response to H2O2 and UV radiation. Mutation of the EphA2 protein kinase domain (c.2003G > A, p. G668D) had a limited effect on H2O2 and UV radiation-induced cell apoptosis. We confirmed this change with an experiment on UV-treated mice. The present study established a novel association between EphA2 and LEC apoptosis.

Candidate genes identification and RNA-seq based pathway analysis associated with primary angle-closure glaucoma with cataract

BACKGROUND

Cataract is commonly observed in patients with primary angle-closure glaucoma; however, its underlying pathological mechanisms remain unclear. This study aimed to improve our knowledge on the pathological processes involved in primary angle-closure glaucoma (PACG) by identifying potential prognostic genes associated with cataract progression.

METHODS

Thirty anterior capsular membrane samples were collected from PACG patients with cataracts and age-related cataracts. Differentially expressed genes (DEGs) between these two cohorts were analyzed using high-throughput sequencing. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to screen the DEGs, and potential prognostic markers and their coexpression network were then predicted by bioinformatic analyses. The DEGs were further validated by reverse transcription-quantitative polymerase chain reaction.

RESULTS

A total of 399 DEGs were found to be specifically associated with cataracts development in PACG patients, among which 177 and 221 DEGs were upregulated and downregulated, respectively. STRING and Cytoscape network analyses revealed seven genes-CTGF, FOS, CAV1, CYR61, ICAM1, EGR1, and NR4A1-that were remarkably enriched and mainly involved in the MAPK, PI3K/Akt, Toll-like receptor, and TNF signaling pathways. RT-qPCR-based validation further confirmed that the sequencing results were accurate and reliable.

CONCLUSIONS

Herein, we identified seven genes and their signaling pathways that may contribute to cataract progression in patients with high intraocular pressure. Taken together, our findings highlight new molecular mechanisms that may explain the high incidence of cataracts in PACG patients. In addition, the genes identified herein may represent new foundations for the development of therapeutic strategies for PACG with cataract.

Crosstalk between ROCK1 and PYROXD1 regulates CAFs activation and promotes laryngeal squamous cell carcinoma metastasis

We previously found that the Rho-associated kinase 1 (ROCK1) activated Cancer-associated fibroblasts (CAFs) to promote LSCC metastasis. Accumulating evidence indicates that pyridine nucleotide-disulfide oxidoreductase domain 1 (PYROXD1) is an oncogene; however, the crosstalk between ROCK1 and PYROXD1 in LSCC metastasis remains largely unknown. Here, we found that ROCK1 could target PYROXD1. The knockdown of ROCK1 expression reduces the expression of PYROXD1, while the knockdown of PYROXD1 expression did not alter the expression of ROCK1 indicating that ROCK1 is upstream of PYROXD1. Further, LSCC cells cocultured with PYROXD1 knocked-down CAFs exhibited lower proliferation, migration, invasion and metastasis abilities. Conversely, LSCC cells cocultured with PYROXD1-overexpressing CAFs showed opposite results. In conclusion, the crosstalk between ROCK1 and PYROXD1 regulated CAFs activation and promoted LSCC metastasis.

FOXO4 mediates resistance to oxidative stress in lens epithelial cells by modulating the TRIM25/Nrf2 signaling

Oxidative stress damage to the lens is a key factor in most cataracts. Forkhead box O 4 (FOXO4), a member of the forkhead box O family, plays a pivotal role in oxidative stress. FOXO4 is upregulated in lens of age-related cataract patients, but its role in cataract has not been elucidated. Herein, we investigated the role and mechanism of FOXO4 during oxidative stress damage in lens epithelial cells. H₂O₂ treatment enhanced FOXO4 expression in HLEpiC cells. Short hairpin RNAs mediated FOXO4 silence aggravated H₂O₂-induced cell apoptosis. In addition, upon H₂O₂ exposure, silencing of FOXO4 reduced SOD and CAT activities, as well as increased intracellular MDA and ROS levels. FOXO4 silencing also inhibited Nrf2 nuclear translocation, followed by reducing the expressions of Nrf2-governed antioxidant genes HO-1 and NOQ-1. Exogenous overexpression of FOXO4 was also involved in this study and exhibited opposite effects of FOXO4-silencing. Mechanistically, FOXO4 directly bound the promoter of TRIM25 and regulated its transcription, thereby activating the Nrf2 signaling. Taken together, in the condition of oxidative stress, the expression of FOXO4 showed a compensatory upregulation and it exhibited an anti-oxidative effect by modulating the transcription of TRIM25, thus activating the Nrf2 signaling. The FOXO4/TRIM25/Nrf2 axis may be associated with the pathological mechanisms of cataract.

Biliverdin Reductase A Protects Lens Epithelial Cells against Oxidative Damage and Cellular Senescence in Age-Related Cataract

Age-related cataract (ARC) is the common cause of blindness globally. Reactive oxygen species (ROS), one of the greatest contributors to aging process, leads to oxidative damage and senescence of lens epithelial cells (LECs), which are involved in the pathogenesis of ARC. Biliverdin reductase A (BVRA) has ROS-scavenging ability by converting biliverdin (BV) into bilirubin (BR). However, little is known about the protective effect of BVRA against ARC. In the present study, we measured the expression level of BVRA and BR generation in human samples. Then, the antioxidative property of BVRA was compared between the young and senescent LECs upon stress condition. In addition, we evaluated the effect of BVRA on attenuating H₂O₂-induced premature senescence in LECs. The results showed that the mRNA expression level of BVRA and BR concentration were decreased in both LECs and lens cortex of age-related nuclear cataract. Using the RNA interference technique, we found that BVRA defends LECs against oxidative stress via (i) restoring mitochondrial dysfunction in a BR-dependent manner, (ii) inducing heme oxygenase-1 (HO-1) expression directly, and (iii) promoting phosphorylation of ERK1/2 and nuclear delivery of nuclear factor erythroid 2-related factor 2 (Nrf2). Intriguingly, the antioxidative effect of BVRA was diminished along with the reduced BR concentration and repressed nuclear translocation of BVRA and Nrf2 in senescent LECs, which would be resulted from the decreased BVRA activity and impaired nucleocytoplasmic trafficking. Eventually, we confirmed that BVRA accelerates the G1 phase transition and prevents against H₂O₂-induced premature senescence in LECs. In summary, BVRA protects LECs against oxidative stress and cellular senescence in ARC by converting BV into BR, inducing HO-1 expression, and activating the ERK/Nrf2 pathway. This trial is registered with ChiCTR2000036059.

Clinical Analysis of Color Doppler Ultrasound Diagnosis of Senile Cataract Based on Intelligent Processor

In order to improve the effect of on-the-spot diagnosis of senile cataract, this paper combines the intelligent processor to explore the application of color Doppler ultrasound in the clinical analysis of senile cataract. Moreover, this paper measures and calculates the diameter, perimeter, area, volume, or velocity of blood flow reflected by color Doppler ultrasound images. In addition, this paper adopts the measurement method provided by composite measurement to design the intelligent processor. Each measurement analysis package is defined as an independent class, and the data, properties, and methods are encapsulated in a class, which is beneficial to the modular design of the program and the overall management of the system. The experimental results verify that the intelligent processor proposed in this paper has a certain effect in the clinical analysis of color Doppler ultrasound diagnosis of senile cataract.

High MST2 expression regulates lens epithelial cell apoptosis in age-related cataracts through YAP1 targeting GLUT1

Age-related cataract (ARC) is a severe visual impairment disease and its pathogenesis remains unclear. This study investigated the relevance of MST2/YAP1/GLUT1 in ARC development in vivo and in vitro, and explored the role and possible mechanisms of this pathway in oxidative damage-mediated apoptosis of lens epithelial cells (LECs). Western blot analysis and immunohistochemistry showed that MST2 and phosphorylated (p)-YAP (Ser127) protein levels were increased, and YAP1 and GLUT1 protein levels were decreased in LECs of ARC patients and aged mice. Additionally, differential expression of MST2 and YAP1 was associated with H₂O₂-induced apoptosis of human lens epithelial B3 (HLE-B3) cells. CCK-8 and Hoechst 33,342 apoptosis assays showed that MST2 and YAP1 were involved in H₂O₂-induced apoptosis of LECs. Subsequent experiments showed that, during MST2-mediated H₂O₂-induced apoptosis, p-YAP (Ser127) levels were elevated and immunofluorescence revealed nucleoplasmic translocation and inhibition of YAP1 protein expression. Furthermore, GLUT1 was in turn synergistically transcriptionally regulated by YAP1-TEAD1 in dual luciferase reporter assays. In conclusion, our study indicates that the MST2/YAP1/GLUT1 pathway plays a major role in the pathogenesis of ARC and LECs apoptosis, providing a new direction for future development of targeted inhibitors that block this signaling pathway to prevent, delay, or even cure ARC.

The E3 Ligase RNF157 Inhibits Lens Epithelial Cell Apoptosis by Negatively Regulating p53 in Age-Related Cataracts

Purpose

Age-related cataract (ARC) is a major cause of vision impairment worldwide. The E3 ubiquitin ligase RING finger protein 157 (RNF157) is involved in regulating cell survival and downregulated in human cataractous lens samples. However, the function of RNF157 in cataracts remains unclear. This study aimed to determine the role of RNF157 in ARC.

Methods

Real-time polymerase chain reaction (PCR) and Western blotting were used to analyze the expression of RNF157 in clinical lens capsules, rat cataract models, and oxidative stress cell models. Western blot analysis and flow cytometry were used to evaluate cell apoptosis. Co-IP assay, protein stability assay, and ubiquitination assay were used to detect the interaction between RNF157 and its substrate p53.

Results

The expression of RNF157 was downregulated in human cataract samples, UVB-induced rat cataract model, and H2O2-treated human lens epithelial cells (LECs). Ectopic expression of RNF157 protected LECs from H2O2-induced apoptosis. In contrast, knockdown of RNF157 enhanced oxidative stress-induced apoptotic cell death. Moreover, silence of RNF157 in the rat ex vivo lens model exacerbated lens opacity. Mechanistically, RNF157 causes ubiquitination and degradation of the tumor antigen p53. Overexpression of p53 eliminated the antiapoptotic effects of RNF157, whereas p53 knockdown rescued RNF157 silencing-induced cell death.

Conclusions

Our findings revealed that reduced RNF157 expression promoted LEC apoptosis by upregulating p53 in cataracts, suggesting that the regulation of RNF157 expression may serve as a potential therapeutic strategy for cataracts.

Knockdown of lncRNA TUG1 protects lens epithelial cells from oxidative stress-induced injury by regulating miR-196a-5p expression in age-related cataracts

Oxidative stress plays an important role in the pathogenesis of cataracts. Under oxidative stress, apoptosis of lens epithelial cells (LECs) is activated, which may cause lens opacity and accelerate the development of cataracts. Long non-coding RNA (lncRNA) and microRNA (miRNA/miR) are involved in cataracts. Previous studies have demonstrated that lncRNA taurine upregulated 1 (TUG1) promotes cell apoptosis induced by ultraviolet radiation by downregulating the expression of miR-421. However, the mechanism underlying TUG1 in age-related cataract remains to be elucidated. The present study aimed to investigate the effect of TUG1 in age-related cataracts and to determine the related underlying molecular mechanism. In the present study, the association between TUG1 and microRNA (miR)-196a-5p was predicted using StarBase and verified using a dual luciferase reporter assay in 293 cells. The LEC line SRA01/04 was exposed to 200 µM hydrogen peroxide (H₂O₂) for 24 h to establish an in vitro oxidative stress model. The mRNA expression levels of TUG1 and miR-196a-5p were analyzed using reverse transcription-quantitative PCR, whilst cell viability and apoptosis were determined using MTT and flow cytometry assays, respectively. The protein expression levels of cleaved caspase-3 and caspase-3 in SRA01/04 cells were determined using western blotting. The results of the present study revealed that TUG1 directly targeted miR-196a-5p expression. In addition, the expression levels of miR-196a-5p were downregulated in SRA01/04 cells following oxidative stress, whilst TUG1 expression was upregulated. Cell transfection with TUG1-small interfering RNA (siRNA) upregulated miR-196a-5p expression levels in SRA01/04 cells, which was reversed following co-transfection with the miR-196a-5p inhibitor. Transfection with TUG1-siRNA also reduced the levels of H₂O₂-induced oxidative damage in SRA01/04 cells, which was demonstrated by increased cell viability, reduced levels of apoptosis and downregulated cleaved caspase-3 levels. Conversely, transfection with the miR-196a-5p inhibitor reversed these effects aforementioned. Overexpression of miR-196a-5p reduced H₂O₂-induced oxidative damage in SRA01/04 cells. In conclusion, findings from the present study suggested that knocking down TUG1 expression may protect LECs from oxidative stress-induced apoptosis by upregulating the expression of miR-196a-5p.

Circ_0122396 Protects Human Lens Epithelial Cells from Hydrogen Peroxide-induced Injury by Binding to miR-15a-5p to Stimulate FGF1 Expression

BACKGROUND

Circular_0122396 (circ_0122396) has been reported to be downregulated in age-related cataract (ARC); however, the underlying mechanism remains unknown. The study aimed to reveal the role of circ_0122396 in ARC progression and underneath mechanism.

METHODS

Hydrogen peroxide (H₂O₂) was employed to induce lens epithelial cells (SRA01/04) injury. The RNA expression of circ_0122396, microRNA-15a-5p (miR-15a-5p) and fibroblast growth factor 1 (FGF1) was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by western blot. Cell viability, proliferation and apoptosis were investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-Ethynyl-29-deoxyuridine and flow cytometry analysis, respectively. Oxidative stress was evaluated by superoxide dismutase and catalase activity assay kits and lipid peroxidation malondialdehyde assay kit. Online databases and mechanism assays were used to predict and identify the relationship between miR-15a-5p and circ_0122396 or FGF1.

RESULTS

Circ_0122396 and FGF1 expression were significantly downregulated, but miR-15a-5p expression was upregulated in ARC tissues or/and H₂O₂-treated SRA01/04 cells in comparison with control groups. H₂O₂ treatment repressed cell proliferation and induced cell apoptosis and oxidative stress, which was attenuated after circ_0122396 overexpression. MiR-15a-5p, a target mRNA of circ_0122396, was found to participate in H₂O₂-triggered cell damage by interacting with circ_0122396. Additionally, FGF1 silencing attenuated miR-15a-5p inhibitors-mediated action. Importantly, circ_0122396 regulated FGF1 expression by interaction with miR-15a-5p in H₂O₂-treated SRA01/04 cells.

CONCLUSION

Circ_0122396 ameliorated H₂O₂-triggered cell injury by inducing FGF1 through sponging miR-15a-5p, providing a potential target for ARC therapy.

EphA2 overexpression reduces H2O2-induced damage of lens epithelial cells

Age-related cataract (ARC) is a progressive lens opacification that occurs from middle to old age. Eph-receptor tyrosinekinase-type A2 (EphA2) has been reported to be associated with ARC. This work aims to investigate the molecular mechanism of EphA2 in ARC. We treated human lens epithelial cells (SRA01/04) with different concentration of H₂O₂ to induce lens epithelial cell damage. Then, we found that H₂O₂ treatment significantly suppressed cell viability and enhanced the expression of EphA2 in the SRA01/04 cells. H₂O₂ treatment repressed cell viability and enhanced the levels of reactive oxygen species (ROS) in SRA01/04 cells, which was partly abolished by EphA2 up-regulation. Moreover, EphA2 overexpression reduced H₂O₂-induced apoptosis of SRA01/04 cells. EphA2 up-regulation caused an up-regulation of Bcl-2, and repressed the expression of Bax and Cleaved-caspase-3 in the SRA01/04 cells following H₂O₂ treatment. In conclusion, our data confirm that EphA2 overexpression enhances cell viability and inhibits apoptosis in the H₂O₂-treated SRA01/04 cells, thereby reducing H₂O₂-induced damage of lens epithelial cells. Thus, this work provides new insights into the mechanism of EphA2 in ARC.

ZNF219 protects human lens epithelial cells against H2O2-induced injury via targeting SOX9 through activating AKT/GSK3β pathway

Opacity of the lens caused by cataracts could lead to severe visual impairment and even blindness. Oxidative stress caused by exposure of lens epithelial cells to hydrogen peroxide (H₂O₂) can lead to DNA damage and impair cell function. Therefore, how to prevent lens epithelial cells from being harmed by H₂O₂ is an urgent problem. The ZNF219 gene belongs to the Kruppel like zinc finger gene family, which is involved in a variety of biological processes. In this study, we found the low expression of ZNF219 in H₂O₂-induced HLE-B3 cells. We further noticed ZNF219 could improve the survival rate of H₂O₂-induced HLE-B3 cells, and inhibit the apoptosis and oxidative stress response. Mechanically, ZNF219 protected human lens epithelial cells against H₂O₂-induced injury via targeting SOX9 through activating AKT/GSK3β pathway. We therefore thought ZNF219 was a key protective protein in the oxidative damage of human lens epithelial cells and the pathogenesis of cataract.