Genetic variants in a sodium-dependent vitamin C transporter gene and age-related cataract

Ultraviolet B radiation induces oxidative stress and apoptosis in human lens epithelium cells by activating NF-κB signaling to down-regulate sodium vitamin C transporter 2 (SVCT2) expression

Ultraviolet B (UVB) exposure is reported to cause cataract formation by inducing excessive reactive oxygen species (ROS) and apoptosis in human lens epithelial cells (HLECs). Sodium-dependent Vitamin C transports-2 (SVCT2) is a ascorbic acid (AsA) transporter for that can protect cells and tissues from oxidative stress. Here, we focus on the functional characterization and mechanism analysis of SVCT2 in UVB-treated HLECs. The results showed a significant reduction of SVCT2 expression in HLECs treated with UVB. SVCT2 abated apoptosis and Bax expression and increased Bcl-2 expression. Moreover, SVCT2 decreased ROS accumulation and MDA level, but increased the activities of antioxidant enzymes (SOD and GSH-PX). NF-κB inhibitor (PDTC) alleviated ROS production and apoptosis, and promoted SVCT2 expression in UVB-treated HLECs. Additionally, ROS inhibitor (NAC) suppressed oxidative stress, apoptosis, and induced SVCT2 expression in UVB-treated HLECs, while these effects were significantly abated due to the activation of NF-κB signaling. Furthermore, SVCT2 facilitated 14C-AsA absorption in UVB-treated HLECs. Together, our findings demonstrated that UVB exposure-induced ROS generation, which further activated NF-κB signaling to down-regulate SVCT2 expression in HLECs. Then, downregulated SVCT2 promoted ROS accumulation and induced apoptosis by decreasing AsA uptake. Our data reveal a novel NF-κB/SVCT2/AsA regulatory pathway and suggest the therapeutic potential of SVCT2 in UVB-induced 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.

Investigating the association of testosterone with survival in men and women using a Mendelian randomization study in the UK Biobank

Life expectancy in the developed West is currently stagnated and remains shorter in men than women. Well-established evolutionary biology theory suggests lifespan trades-off against reproductive success, possibly sex-specifically. We examined whether a key driver of reproductive success, testosterone, affected survival using a Mendelian randomization longevity study in the UK Biobank to obtain unbiased estimates, along with control exposures. We applied published genetic instruments for testosterone to obtain inverse variance weighted estimates of associations with survival to (i.e., age at) recruitment, in 167,020 men and 194,174 women. We similarly obtained estimates for a positive control (smoking initiation), and a negative control (absorbate), a marker of vitamin C metabolism. Testosterone was associated with poorer survival (0.10 years younger at recruitment per effect size of testosterone, 95% confidence interval (CI) 0.004 to 0.20). As expected, smoking initiation was also associated with poorer survival (0.37 years younger, 95% CI 0.25 to 0.50), but not absorbate (0.01 years younger, 95% CI - 0.09 to 0.11). Several aspects of a healthy lifestyle (low animal fat diet) and several widely used medications (statins, metformin, dexamethasone and possibly aspirin) may modulate testosterone. Explicitly designing interventions sex-specifically based on these insights might help address stagnating life expectancy and sexual disparities.

Whole Genome Interpretation for a Family of Five

Although best practices have emerged on how to analyse and interpret personal genomes, the utility of whole genome screening remains underdeveloped. A large amount of information can be gathered from various types of analyses via whole genome sequencing including pathogenicity screening, genetic risk scoring, fitness, nutrition, and pharmacogenomic analysis. We recognize different levels of confidence when assessing the validity of genetic markers and apply rigorous standards for evaluation of phenotype associations. We illustrate the application of this approach on a family of five. By applying analyses of whole genomes from different methodological perspectives, we are able to build a more comprehensive picture to assist decision making in preventative healthcare and well-being management. Our interpretation and reporting outputs provide input for a clinician to develop a healthcare plan for the individual, based on genetic and other healthcare data.

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

Background

Age-related cataract (ARC) is a serious visual impairment disease, and its pathogenesis is unclear. This article aims to investigate the role of ROCK1 in the apoptosis of lens epithelial cells (LECs) in age-related cataracts.

Methods

We collect anterior capsule samples from normal people, patients with age-related cataracts, young mice and naturally aging cataract mice. The oxidative stress-induced apoptosis model was constructed by cultivating HLE-B3 cells with H₂O₂. MTT, Hoechst 33342, and TUNEL assay were performed to explore proliferation and apoptosis. HE assay was used to observe cell morphology. The gene and protein expression were assessed by quantitative real-time PCR, western blot, immunofluorescence, and immunohistochemical staining.

Result

The results from the clinic and mice experiments showed that the numbers of lens epithelial cells from cataract individuals were less than the control individuals. In vitro, the apoptotic cells were increased in lens epithelial cells under H₂O₂ treatment. The ROCK1 protein level increased in the lens epithelial cells from age-related cataract patients and the old mice, respectively. Meanwhile, the up-regulation of the ROCK1 gene was associated with H₂O₂-induced HLE-B3 cells apoptosis. MTT and apoptosis assay showed ROCK1 was necessary in mediating H₂O₂-induced lens epithelial cells apoptosis through ROCK1 over-expression and knockdown experiment, respectively. Further investigation showed that p53 protein levels had been increased during ROCK1-mediated apoptosis in response to H₂O₂. Besides, ROCK1 phosphorylated p53 at ser15 to up-regulate its protein level.

Conclusions

This study established the novel association of ROCK1/p53 signaling with lens epithelial cells apoptosis and age-related cataract genesis.