Mendelian randomization implicates causal association between epigenetic age acceleration and age-related eye diseases or glaucoma endophenotypes.

BACKGROUND: Age-related eye diseases (AREDs) have become increasingly prevalent with the aging population, serving as the leading causes of visual impairment worldwide. Epigenetic clocks are generated based on DNA methylation (DNAm) levels and are considered one of the most promising predictors of biological age. This study aimed to investigate the bidirectional causal association between epigenetic clocks and common AREDs or glaucoma endophenotypes. METHODS: Instrumental variables for epigenetic clocks, AREDs, and glaucoma endophenotypes were obtained from corresponding genome-wide association study data of European descent. Bidirectional two-sample Mendelian randomization (MR) was employed to explore the causal relationship between epigenetic clocks and AREDs or glaucoma endophenotypes. Multivariable MR (MVMR) was used to determine whether glaucoma endophenotypes mediated the association of epigenetic clocks with glaucoma. Multiple sensitivity analyses were conducted to confirm the robustness of MR estimates. RESULTS: The results showed that an increased intrinsic epigenetic age acceleration (HorvathAge) was significantly associated with an increased risk of primary open-angle glaucoma (OR = 1.04, 95% CI 1.02 to 1.06, P = 6.1E-04). The epigenetic age acceleration (EEA) of HannumAge was related to a decreased risk of primary angle-closure glaucoma (OR = 0.92, 95% CI 0.86 to 0.99, P = 0.035). Reverse MR analysis showed that age-related cataract was linked to decreased HannumAge (ß = -0.190 year, 95% CI -0.374 to -0.008, P = 0.041). The EEA of HannumAge (ß = -0.85 µm, 95% CI -1.57 to -0.14, P = 0.019) and HorvathAge (ß = -0.63 µm, 95% CI -1.18 to -0.08, P = 0.024) were associated with decreased central corneal thickness (CCT). PhenoAge was related to an increased retinal nerve fiber layer thickness (ß = 0.06 µm, 95% CI 0.01 to 0.11, P = 0.027). MVMR analysis found no mediation effect of CCT in the association of HannumAge and HorvathAge with glaucoma. DNAm-based granulocyte proportions were significantly associated with presbyopia, rhegmatogenous retinal detachment, and intraocular pressure (P < 0.05). DNAm-based plasminogen activator inhibitor-1 levels were significantly related to age-related macular degeneration and intraocular pressure (P < 0.05). CONCLUSION: The present study revealed a causal association between epigenetic clocks and AREDs. More research is warranted to clarify the potential mechanisms of the biological aging process in AREDs.

Slit2 Promotes H2O2-Induced Lens Epithelial Cells Oxidative Damage and Age-Related Cataract.

PURPOSE: To analyze the role of Slit2 in lens epithelial cell oxidative damage and its underlying mechanism. METHODS: Human lens epithelial cells (SRA01/04 cells) and rat transparent lens were cultured with H2O2 to establish cell oxidative stress models and rat cataract models. Immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot assays were employed to detect Slit2 levels within age-related cataracts(ARC) lens anterior capsule samples, rat cataract models, and cell oxidative stress models. In this study, qRT-PCR and Western blot assays were performed to derermine E-cadherin, N-cadherin, occludens1(ZO-1), α-SMA(α­smooth muscle actin), Bcl-2, Bax, p-AKT, and AKT levels. In addition, Flow cytometry were performed to examine reactive oxygen species (ROS) and cell apoptosis. Cell viability, invasion, and migration were detected by CCK8, Transwell, and Wound healing. RESULTS: Increased expression of Slit2 was found in ARC lens anterior capsule samples, H2O2-induced rat cataract models, and Human lens epithelial cells (HLECs) oxidative stress models. H2O2 significantly increased cell apoptosis and ROS generation, also accelerating cell migration, invasion, and epithelial-mesenchymal transition (EMT). In addition, H2O2 treatment repressed AKT phosphorylation and cell viability. Knock-down of Slit2 promoted cell viability and AKT phosphorylation levels, as well as repressed cell invasion, migration, apoptosis, ROS production and EMT. CONCLUSION: Slit2 promoted lens epithelial cells oxidative stress damage via the AKT signalling pathways, providing a novel insight in ARC treatment.

Subgroup Analysis from a Phase 1/2 Randomized Clinical Trial of 2.6% EDTA Ophthalmic Solution in Patients with Age-Related Cataract.

PURPOSE: To explore the efficacy of topical 2.6% EDTA ophthalmic solution (C-KAD) as a treatment to improve visual function for the subgroup of patients with loss of contrast sensitivity (CS) due to early-stage age-related cataract. DESIGN: Subgroup analysis of randomized, double-blinded, placebo-controlled, multicenter phase 1/2 clinical trial data. METHODS: Both eyes of subjects in the intent-to-treat population, with mesopic CS scores between 1 and 7 grating patches (range 0-9, each patch representing 0.15 logCS), at baseline in all five frequencies, were included. The proportion of eyes with clinically significant mesopic CS improvement and mean changes in mesopic CS at spatial frequencies between 1.5 to 18 cycles per degree (cpd), and summary metrics of area under the log CS function (AULCSF), were analyzed. Other exploratory outcomes analyzed included best-corrected visual acuity (BCVA) and lens density for a smaller subgroup of eyes for which Scheimpflug images were available. RESULTS: Forty-one subject eyes were included in the subgroup analysis (C-KAD n = 21, placebo n = 20). The primary endpoint of the proportion of eyes with mesopic CS improvements ≥ 0.30 logCS (equivalent to 100% CS improvement) in at least two of the five spatial frequencies was significantly greater for C-KAD (66.7% versus 35.0% for placebo, P = .043) at Day 120. C-KAD met the primary protocol endpoint in this subgroup analysis. The proportion of eyes achieving ≥ 0.30 logCS improvement (mesopic) as measured in AULCSF was also significantly greater for C-KAD, with 42.9% compared to 15.0% for placebo (P = .050) at Day 120. The mean change in AULCSF (mesopic) was significantly larger for C-KAD, with 0.25 logCS improvement, versus placebo with 0.06 logCS improvement (P = .020) at Day 120. C-KAD also showed significant mesopic CS improvements at spatial frequencies 3 and 6 cpd, with 0.28 logCS (P = .004) and 0.31 logCS (P = .047) versus placebo at Day 120. Positive BCVA trends and statistical significance in lens density were also observed. CONCLUSIONS: A significant treatment effect of C-KAD in visual function and vision quality was observed consistently. These promising results suggest a novel, non-invasive pharmacological treatment to improve vision in patients with early-stage cataract.

Identification of spontaneous age-related cataract in Microtus fortis. / ä¸œæ–¹ç”°é¼ è‡ªå‘æ€§å¹´é¾„ç›¸å ³æ€§ç™½å† éšœçš„é‰´å®š.

OBJECTIVES: Age-related cataract is the most common type of adult cataract and a leading cause of blindness. Currently, there are few reports on the establishment of animal models for age-related cataract. During the experimental breeding of Microtus fortis (M. fortis), we first observed that M. fortis aged 12 to 15 months could naturally develop cataracts. This study aims to explore the possibility of developing them as an animal model for age-related cataract via identifing and analyzing spontaneous cataract in M. fortis. METHODS: The 12-month-old healthy M. fortis were served as a control group and 12-month-old cataractous M. fortis were served as an experimental group. The lens transparency was observed using the slit-lamp biomicroscope. Hematoxylin and eosin staining was used to detect pathological changes in the lens. Biochemical detection methods were applied to detect blood routine, blood glucose levels, the serum activities of superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in both groups. Finally, real-time RT-PCR was used to detect the transcription levels of cataract-related genes in the lens of 2 groups. RESULTS: Compared with the control group, the lens of cataract M. fortis showed severely visible opacity, the structure of lens was destroyed seriously, and some pathological damage, such as swelling, degeneration/necrosis, calcification, hyperplasia, and fiber liquefaction were found in lens epithelial cells (LECs). The fibrous structure was disorganized and irregularly distributed with morgagnian globules (MGs) aggregated in the degenerated lens fibers. There was no statistically significant difference in blood glucose levels between the experimental and control groups (P>0.05). However, white blood cell (WBC) count (P<0.05), lymphocyte count (P<0.01), and lymphocyte ratio (P<0.05) were significantly decreased, while neutrophil percentage (P<0.05) and monocyte ratio (P<0.01) were significantly increased. The serum activities of SOD and GSH-Px (both P<0.05) were both reduced. The mRNAs of cataract-related genes, including CRYAA, CRYBA1, CRYBB3, Bsfp1, GJA3, CRYBA2, MIP, HspB1, DNase2B, and GJA8, were significantly downregultaed in the lenses of the experimental group (all P<0.05). CONCLUSIONS: There are significant differences in lens pathological changes, peroxidase levels, and cataract-related gene expression between cataract and healthy M. fortis. The developed cataract spontaneously in M. fortis is closely related to age, the cataract M. fortis might be an ideal animal model for the research of age-related cataract.

A role for YAP/FOXM1/Nrf2 axis in oxidative stress and apoptosis of cataract induced by UVB irradiation.

This study aims to investigate the hypothesis that Yes-associated protein (YAP) significantly regulates antioxidant potential and anti-apoptosis in UVB-induced cataract by exploring the underlying molecular mechanisms. To investigate the association between YAP and cataract, various experimental techniques were employed, including cell viability assessment, Annexin V FITC/PI assay, measurement of ROS production, RT-PCR, Western blot assay, and Immunoprecipitation. UVB exposure on human lens epithelium cells (HLECs) reduced total and nuclear YAP protein expression, increased cleaved/pro-caspase 3 ratios, decreased cell viability, and elevated ROS levels compared to controls. Similar Western blot results were observed in in vivo experiments involving UVB-treated mice. YAP knockdown in vitro demonstrated a decrease in the protein expression of FOXM1, Nrf2, and HO-1, which correlated with the mRNA expression, accompanied by an increase in cell apoptosis, caspase 3 activation, and the release of ROS. Conversely, YAP overexpression mitigated these effects induced by UVB irradiation. Immunoprecipitation revealed a FOXM1-YAP interaction. Notably, inhibiting FOXM1 decreased Nrf2 and HO-1, activating caspase 3. Additionally, administering the ROS inhibitor N-acetyl-L-cysteine (NAC) effectively mitigated the apoptotic effects induced by oxidative stress from UVB irradiation, rescuing the protein expression levels of YAP, FOXM1, Nrf2, and HO-1. The initial findings of our study demonstrate the existence of a feedback loop involving YAP, FOXM1, Nrf2, and ROS that significantly influences the cell apoptosis in HLECs under UVB-induced oxidative stress.

Aging of the eye: Lessons from cataracts and age-related macular degeneration.

Aging is the greatest risk factor for chronic human diseases, including many eye diseases. Geroscience aims to understand the effects of the aging process on these diseases, including the genetic, molecular, and cellular mechanisms that underlie the increased risk of disease over the lifetime. Understanding of the aging eye increases general knowledge of the cellular physiology impacted by aging processes at various biological extremes. Two major diseases, age-related cataract and age-related macular degeneration (AMD) are caused by dysfunction of the lens and retina, respectively. Lens transparency and light refraction are mediated by lens fiber cells lacking nuclei and other organelles, which provides a unique opportunity to study a single aging hallmark, i.e., loss of proteostasis, within an environment of limited metabolism. In AMD, local dysfunction of the photoreceptors/retinal pigmented epithelium/Bruch's membrane/choriocapillaris complex in the macula leads to the loss of photoreceptors and eventually loss of central vision, and is driven by nearly all the hallmarks of aging and shares features with Alzheimer's disease, Parkinson's disease, cardiovascular disease, and diabetes. The aging eye can function as a model for studying basic mechanisms of aging and, vice versa, well-defined hallmarks of aging can be used as tools to understand age-related eye disease.

Association of CUL4B with the pathogenesis of age-related cataract.

PURPOSE: Age-related cataract (ARC) is the most common cause of visual impairment and blindness in older adults. However, the role of CUL4B in the ARC remains unclear. Therefore, we investigated CUL4B expression and its effects on apoptosis. MATERIALS AND METHODS: CUL4B expression levels were detected by a quantitative real-time polymerase chain reaction from the anterior lens capsules of patients with ARC and HLE-B3 cells treated with different concentrations of H2O2. CUL4B expression was silenced by siRNA transfection to evaluate apoptosis. CUL4B and apoptotic proteins B cell lymphoma 2 (Bcl-2), myeloid cell leukemia 1 (Mcl-1), caspase-3, cleaved caspase-3, Bax, Bak, and Bid were assessed using western blot analysis. Apoptosis was monitored using the TUNEL assay. RESULTS: CUL4B expression was downregulated in the anterior lens capsules (P < 0.0001) and H2O2-treated HLE-B3 cells (P = 0.0405). CUL4B protein levels were significantly lower in 100 µmol/L (P = 0.0012) and 200 µmol/L (P = 0.0041) H2O2-treated HLE-B3 cells than in the untreated cells. CUL4B expression was significantly knocked down at the mRNA (P = 0.0043) and protein levels (P = 0.0002) in HLE-B3 cells. Bcl-2 (P = 0.0199), Mcl-1 (P = 0.0042), and caspase-3 (P = 0.0142) were significantly downregulated, whereas cleaved caspase-3 (P = 0.0089) and Bak (P = 0.009) were significantly upregulated in the knockdown group. The TUNEL assay showed a greater induction of apoptosis. CONCLUSIONS: CUL4B downregulation promotes the apoptosis of lens epithelial cells. Our study may help in understanding the role of CUL4B in ARC pathogenesis.

Effect of cervical pillow in phacoemulsification surgery for age-related cataract patients: a prospective randomized controlled study.

PURPOSE: To explore the application effect of cervical pillow in phacoemulsification surgery for age-related cataract patients. METHODS: 104 cases of age-related cataract patients admitted to our hospital in June 2023 were enrolled and divided into the control group (traditional supine position) and the experimental group (the cervical pillow supine position) by the digital parity method (52 cases per group). The two groups were evaluated for the discomfort score, the satisfaction of patients and doctors, the head displacement rate, the number of displacement, the operation time and the time of body position during the operation and after the operation. RESULTS: There was no significant difference in the gender (P = 0.84), age (P = 0.86), course of disease (P = 0.82) and the time spent on position placement (P = 0.15) of the two groups. The patient in the experimental group had lower discomfort score (P = 0.0001), higher patients satisfaction (P = 0.0001) and higher doctors satisfaction (P = 0.0001) than patients in the control group. There was no significant difference between the experimental group and the control group in the proportion of intraoperative (P = 0.36) and postoperative pain (P = 0.65). Besides, the number of head transfers (P = 0.001), number of head shifts (P = 0.0001), the surgical time (P = 0.0001) and laparoscopic time (P = 0.0001) in the experimental group were significantly lower than those in the control group. CONCLUSION: The additional cervical pillow for age-related cataract patients in the traditional supine position during the operation will not increase the preparation time before the operation, but will help improve the patient satisfaction, improve the comfort and maintain a good position of the operative eye field, bringing obvious comfort and smooth operation for the surgeon in the operation, thus reducing the risk of the operation, shortening the operation time.

LncRNA MEG3 regulates ferroptosis of lens epithelial cells via PTBP1/GPX4 axis to participate in age-related cataract.

Age-related cataract (ARC) is regarded as the principal cause of vision impairment among the aged. The regulatory role of long noncoding RNAs (LncRNAs) in ARC remains unclear. The lncRNA maternally expressed gene 3 (MEG3) has been reported to promote ARC progression, and the underlying mechanism was further investigated in this study. Lens epithelium samples were collected to verify the expression of MEG3. Lens epithelial cells (LECs) were treated with H2O2 to mimic microenvironment of ARC in vitro. Cell viability, reactive oxygen species, and ferroptosis were evaluated during the in viro experiments. In the present work, lncRNA MEG3 was highly expressed in ARC group, compared with normal group. MEG3 was induced, cell viability and glutathione peroxidase 4 (GPX4) level were inhibited, and ferroptosis was promoted in H2O2 treated LECs. LncRNA MEG3 silence reversed the effects of H2O2 on viability and ferroptosis in LECs. Thereafter, lncRNA MEG3 was found to bind to PTBP1 for GPX4 degradation. Silencing of GPX4 reversed the regulation of lncRNA MEG3 inhibition in H2O2-treated LECs. To sum up, lncRNA MEG3 exhibited high expression in ARC. In H2O2-induced LECs, inhibition of lncRNA MEG3 accelerated cell viability and repressed ferroptosis by interaction with PTBP1 for GPX4 messenger RNA decay. Targeting lncRNA MEG3 may be a novel treatment of ARC.

Proportion and risk factors of zonulopathy in patients with age-related cataract.

Purpose: To investigate the proportion of zonulopathy in patients with age-related cataract, and further explore demographics and ocular characteristics, as well as potential risk factors. Methods: Hospital-based, observational, cross-sectional study. We enrolled consecutive patients who were 45 years or older and diagnosed with age-related cataract and underwent surgery between October 2022 and April 2023 at the Division of Cataract, Beijing Tongren Hospital. Zonulopathy was diagnosed based on intraoperative signs. We calculated the total proportion, age, and gender specific proportions of zonulopathy. We compared the demographic and ocular characteristics between the cases with and without zonulopathy. Univariate and multivariate logistic regression analyses were employed to determine the risk factors associated with the presence of zonulopathy in patients with age-related cataract. Results: A total of 640 age-related cataract patients with a median age of 70.0 (64.0-77.0) were enrolled. Zonulopathy was diagnosed intraoperatively in 70 patients (10.9%). Compared with the patients having no zonulopathy, those with zonulopathy were likely to be older (P < 0.001), have a shallower central ACD (P < 0.001), a thicker lens (P < 0.001) and a shorter AL (P = 0.010). Logistic regression analyses showed that the risk predictors associated with the presence of zonulopathy in patients with age-related cataract were older age (OR, 1.042; P = 0.035) and shallower central ACD (OR, 0.834; P < 0.001). Conclusion: Zonulopathy in age-related cataract patients is not an uncommon finding. Clinicians should be mindful of zonulopathy in patient population with advanced age and shallower ACD.

IGF-1 rs6218 polymorphisms modulate the susceptibility to age-related cataract.

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.

CircRNA HLCS regulates lens epithelial cell apoptosis via miR-338-3p/BPNT1 axis.

PURPOSE: The purpose of this study was to investigate the effect of circ_HLCS on age-related cataract (ARC). METHODS: Circ_HLCS, microRNA (miR)-338-3p, and bisphosphate 3'-nucleotidase 1 (BPNT1) were quantified by quantitative real-time polymerase chain reaction or western blot. Cell proliferation and cell viability were assessed by the 5-Ethynyl-2'-deoxyuridinr and cell counting kit-8 assays. Cell apoptosis was detected by flow cytometry. Targeted correlations among circ_HLCS, miR-338-3p, and BPNT1 were verified by the dual-luciferase reporter and RNA pull-down assays. RESULTS: circ_HLCS was diminished in ARC tissues and UV-treated SRA01/04 cells. Elevated content of circ_HLCS undermined UV-induced cell proliferation inhibition and apoptosis. Mechanistically, circ_HLCS directly targeted miR-338-3p, and circ_HLCS regulated BPNT1 expression through miR-338-3p. Furthermore, reduction of miR-338-3p ameliorated UV-induced SRA01/04 cell damage by increasing BPNT1 expression. CONCLUSION: Taken together, these data suggested that circ_HLCS inhibited apoptosis of UV-treated SRA01/04 cells by miR-338-3p/BPNT1 axis. Therefore, circ_HLCS might be a potential therapeutic target for ARC.

Lanosterol regulates abnormal amyloid accumulation in LECs through the mediation of cholesterol pathway metabolism.

Age-related cataract (ARC) is the predominant cause of global blindness, linked to the progressive aging of the lens, oxidative stress, perturbed calcium homeostasis, hydration irregularities, and modifications in crystallin proteins. Currently, surgical intervention remains the sole efficacious remedy, albeit carrying inherent risks of complications that may culminate in irreversible blindness. It is urgent to explore alternative, cost-effective, and uncomplicated treatment modalities for cataracts. Lanosterol has been widely reported to reverse cataracts, but the mechanism of action is not yet clear. In this study, we elucidated the mechanism through which lanosterol operates in the context of cataract reversal. Through the targeted suppression of sterol regulatory element-binding protein 2 (SREBP2) followed by lanosterol treatment, we observed the restoration of lipid metabolism disorders induced by SREBP2 knockdown in lens epithelial cells (LECs). Notably, lanosterol exhibited the ability to effectively counteract amyloid accumulation and cellular apoptosis triggered by lipid metabolism disorders. In summary, our findings suggest that lanosterol, a pivotal intermediate in lipid metabolism, may exert its therapeutic effects on cataracts by influencing lipid metabolism. This study shed light on the treatment and pharmaceutical development targeting Age-related Cataracts (ARC).

CircSTRBP contributes to H2O2-induced lens epithelium cell dysfunction through increasing NOX4 mRNA stability by recruiting IGF2BP1.

Previous studies have shown that the development of age-related cataract (ARC) is involved in lens epithelium dysfunction, which is associated with abnormally expressed circular RNAs (circRNAs). The current work aims to probe the role of circSTRBP (hsa_circ_0088,427) in hydrogen peroxide (H2O2)-induced lens epitheliums. Lens epithelium tissues were harvested from ARC or normal subjects (n = 23). CircSTRBP, spermatid perinuclear RNA binding protein (STRBP), and nicotinamide adenine dinucleotide phosphate oxidase subunit 4 (NOX4) levels were measured using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Cell proliferation, cycle progression, and apoptosis were assessed using 5-ethynyl-2'-deoxyuridine (EdU), Cell Counting Kit-8 (CCK-8), and flow cytometry assays. Caspase 3 activity, reactive oxygen species (ROS), malondialdehyde (MDA), and Glutathione peroxidases (GSH-PX) levels were detected using corresponding kits. NOX4 protein level was determined using Western blot. The interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and circSTRBP or NOX4 was assessed through RNA immunoprecipitation (RIP). CircSTRBP and NOX4 abundances were increased in lens epithelium samples from ARC patients and H2O2-treated SRA01/04 cells. CircSTRBP knockdown might abolish H2O2-triggered SRA01/04 cell proliferation repression and apoptosis and oxidative stress promotion. In mechanism, circSTRBP is bound with IGF2BP1 and improves the stability and expression of NOX4 mRNA in SRA01/04 cells. CircSTRBP facilitated H2O2-induced SRA01/04 cell apoptosis and oxidative stress through by enhancing NOX4 mRNA stability via recruiting IGF2BP1, providing novel insights for ARC progression and treatment.

Hypothyroidism is a causal determinant of age-related cataract risk in European population: a Mendelian randomization study.

Objective: To determine whether there is a causal relationship between thyroid dysfunction and the risk of age-related cataract (ARC) in the European population. Design: A two-sample Mendelian randomization (MR) study. Methods: Hypothyroidism, hyperthyroidism, free thyroxine (fT4), and thyrotropin (TSH) were selected as exposures. The single nucleotide polymorphisms (SNP) of hypothyroidism and hyperthyroidism were obtained from the genome-wide association studies (GWAS) of the IEU database, including 337,159 subjects. Data for fT4 and TSH (72,167 subjects) were extracted from the ThyroidOmics Consortium. ARC was used as the outcome. The SNPs associated with ARC were selected from a GWAS of 216,362 individuals in the FinnGen database. The main method used was the inverse variance-weighted method, together with four complementary methods. Sensitivity analyses were performed using Cochran's Q test, MR-PRESSO, MR-Egger regression and leave-one-out test. MR pleiotropy was used to test for pleiotropy. MR Steiger test was used to test for the directionality. Results: Two-sample MR analysis revealed a positive association between genetically predicted hypothyroidism and risk of ARC (OR = 2.501, 95% CI: 1.325-4.720; P = 0.004). Hyperthyroidism, circulating fT4 and TSH levels did not have a significant causal effect on ARC (P > 0.05). The results were robust and reliable, and no horizontal pleiotropy was found after sensitivity analyses. In the MR Steiger test, we found no reverse causal effects of hypothyroidism on the ARC (P <0.001). Conclusions: Our study provides strong evidence that hypothyroidism is a causal determinant of ARC risk.

Review on the potential roles of traditional Chinese medicines in the prevention, treatment, and postoperative recovery of age-related cataract.

ETHNIC PHARMACOLOGICAL RELEVANCE: Cataract is the most common cause of blindness worldwide, a visual disorder caused by a clouded lens that seriously affects People's Daily lives. Age-related cataract (ARC) is the most common type of cataract due to long-term combined effects of many factors, and its pathogenesis is varied. At present, the surgery is the main treatment for cataracts, but it is still limited to the prevention, treatment of early cataracts and the postoperative complications care. While, its drug treatments are still in the stage of exploration and research. Traditional Chinese Medicine (TCM), a unique resource in China, is conceived under the guidance of traditional Chinese medicine theory and has little toxicity and side effects, but it has made great progress in the treatment and prevention of ARC. AIM OF THIS REVIEW: This review presents an overview of the pathogenesis of ARC in both traditional and modern medicines and summarizes the history and therapeutic effect of TCM on ARC including their formula, crude drugs and active components, and also the other auxiliary methods. METHODS: A number of recognized databases like SciFinder, PubMed, Science Direct, Google Scholar, and China National Knowledge Infrastructure (CNKI) were extensively explored by using keywords and phrases such as "cataract", "age-related cataract", "traditional medicine", "ethnopharmacology", "herbs", "medicinal plants", or other relevant terms, and the plants/phytoconstituents that are evaluated in the models of age-related cataract. As well as the current TCM adjuvant therapy used in the clinical treatment were summarized. RESULTS: TCM revealed to plays an active role in treating age-related cataract, via multi-pathway and multi-target, and can treat or delay ARC by inhibiting abnormal glucose metabolism, antioxidant damage, inhibiting LEC apoptosis, and so on, which is in concordance with the good effects of the global use of TCM in clinical application. Concerning the early prevention and treatment of cataract and postoperative complications, TCM and auxiliary methods remain to achieve better clinical effects. CONCLUSION: ARC belongs to the category of "Yuan Yi Nei Zhang" in TCM theory, showing that there are many causes of ARC including aging, and kidney-yang, spleen, sperm and blood deficiencies. At the same time, the viscera gradually decline, as well as yin or yang progressively become weak, especially in the elder people. So, TCM could be mainly based on liver, kidney, and spleen syndrome differentiation, personalizing diagnosis and treatment, following multiple targets, regulating fundamentally yin and yang, and thus justifying the advantages of Chinese medicine in the prevention and treatment of ARC.

CircMAP3K4 Suppresses H2O2-Induced Human Lens Epithelial Cell Injury by miR-630/ERCC6 Axis in Age-Related Cataract.

BACKGROUND: Dysregulated circular RNAs (circRNAs) is involved in the pathogenesis of age-related cataract (ARC). Here, this study aimed to explore the function and mechanism of circMAP3K4 in ARC. METHODS: Human lens epithelial cells were exposed to hydrogen peroxide (H2O2) for functional experiments. qRT-PCR and western blotting analyses were used for the expression detection of genes and proteins. Cell proliferation was tested using cell counting kit-8 and EdU. Flow cytometry was applied to analyze cell apoptosis and cell cycle. The oxidative stress was evaluated by detecting the production of malondialdehyde (MDA), reactive oxygen species (ROS), and superoxide dismutase (SOD). The target relationship between miR-630 and circMAP3K4 or Excision repair cross-complementing group 6 (ERCC6) was analyzed by dual-luciferase reporter assay and RIP assay. RESULTS: CircMAP3K4 was lowly expressed in ARC patients and H2O2-induced HLECs. Functionally, forced expression of circMAP3K4 protected HLECs against H2O2-evoked proliferation inhibition, cell cycle arrest and the promotion of cell apoptosis and oxidative stress. Mechanistically, circMAP3K4 acted as a sponge for miR-630 to regulate the expression of its target ERCC6. MiR-630 was highly expressed while ERCC6 was lowly expressed in ARC patients and H2O2-induced HLECs. Up-regulation of miR-630 could reverse the protective effects of circMAP3K4 on HLECs under H2O2 treatment. In addition, inhibition of miR-630 suppressed H2O2-induced HLEC injury, which was abolished by ERCC6 silencing. CONCLUSION: Forced expression of circMAP3K4 protected HLECs against H2O2-evoked apoptotic and oxidative injury via miR-630/ERCC6 axis, suggesting that circMAP3K4 may function as a potential therapeutic target for ARC.

Lens epithelium cell ferroptosis mediated by m6A-lncRNA and GPX4 expression in lens tissue of age-related cataract.

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.

Identification and quantification of ionising radiation-induced oxysterol formation in membranes of lens fibre cells.

Ionising radiation (IR) is a cause of lipid peroxidation, and epidemiological data have revealed a correlation between exposure to IR and the development of eye lens cataracts. Cataracts remain the leading cause of blindness around the world. The plasma membranes of lens fibre cells are one of the most cholesterolrich membranes in the human body, forming lipid rafts and contributing to the biophysical properties of lens fibre plasma membrane. Liquid chromatography followed by mass spectrometry was used to analyse bovine eye lens lipid membrane fractions after exposure to 5 and 50 Gy and eye lenses taken from wholebody 2 Gy-irradiated mice. Although cholesterol levels do not change significantly, IR dose-dependant formation of the oxysterols 7ß-hydroxycholesterol, 7-ketocholesterol and 5, 6-epoxycholesterol in bovine lens nucleus membrane extracts was observed. Whole-body X-ray exposure (2 Gy) of 12-week old mice resulted in an increase in 7ß-hydroxycholesterol and 7-ketocholesterol in their eye lenses. Their increase regressed over 24 h in the living lens cortex after IR exposure. This study also demonstrated that the IR-induced fold increase in oxysterols was greater in the mouse lens cortex than the nucleus. Further work is required to elucidate the mechanistic link(s) between oxysterols and IR-induced cataract, but these data evidence for the first time that IR exposure of mice results in oxysterol formation in their eye lenses.

Association between obesity and age-related cataract: an updated systematic review and dose-response meta-analysis of prospective cohort studies.

Objective: There are inconsistent findings on the association between obesity and age-related cataract (ARC). This systematic review was done to summarize available findings on the association between obesity [defined by body mass index (BMI)] and ARC by performing a dose-response meta-analysis on eligible prospective cohort studies. Methods: We performed a systematic search in PubMed, Scopus, ISI Web of Knowledge, and Google Scholar until June 2022 to identify eligible publications. Results: In total, 16 studies with a total sample size of 1,607,125 participants were included. Among all of these studies, there were 103,897 cases of ARC. In the follow-up periods ranging between 4 and 28 years, 4,870 cases of nuclear cataract, 1,611 cases of cortical cataract, and 1,603 cases of posterior subcapsular cataracts (PSC) were detected. By comparing the highest and lowest categories of BMI, we found that higher BMI was associated with an increased risk of ARC (RR: 1.18, 95% CI: 1.09-1.28) and PSC (RR: 1.44, 95% CI: 1.08-1.90). In the dose-response analysis, each 5 kg/m2 increase in BMI was associated with a 6 and 27% increased risk of ARC (RR: 1.06, 95% CI: 1.01-1.12) and PSC (RR: 1.27, 95% CI: 1.14-1.41), respectively. In addition, we found a positive association for cortical cataract among high-quality studies, in which higher BMI was associated with a 20% increased risk of cortical cataract (RR: 1.20, 95% CI: 1.02-1.42). In terms of nuclear cataract, we found no significant association either in the comparison between the highest and lowest categories of BMI or in the dose-response meta-analysis. Conclusion: Obesity (defined by BMI) was associated with an increased risk of ARC, PSC, and cortical cataract in adults. However, such a positive association was not seen for nuclear cataract. PROSPERO registration: CRD42022357132.