Ultraviolet B Radiation Stimulates the Interaction between Nuclear Factor of Activated T Cells 5 (NFAT5) and Nuclear Factor-Kappa B (NF-κB) in Human Lens Epithelial Cells

A bibliometric and visualized analysis of the pathogenesis of cataracts from 1999 to 2023

Research on the pathogenesis of cataracts is ongoing and the number of publications on this topic is increasing annually. This study offers an overview of the research status, popular topics, and scholarly tendencies in the field of cataract pathogenesis over recent decades，which helps to guide future research directions, and optimize resource allocation. In the present study, we performed a bibliometric analysis of cataract pathogenesis. Publications from January 1, 1999, to December 20, 2023, were collected from the Web of Science Core Collection (WoSCC), and the extracted data were quantified and analyzed. We analyzed and presented the data using Microsoft Excel, VOSviewer, CiteSpace, and Python. In all, 4006 articles were evaluated based on various characteristics, including publication year, authors, countries, institutions, journals, citations, and keywords. This study utilized VOSviewer to conduct visualized analysis, including co-authorship, co-citation, co-occurrence, and network visualization. The CiteSpace software was used to identify keywords with significant bursts of activity. The number of annual global publications climbed from 76 to 277 between 1999 and 2023, a 264.47% rise. Experimental Eye Research published the most manuscripts (178 publications), whereas Investigative Ophthalmology & Visual Science received the most citations (6675 citations). The most influential and productive country, institution, and author were the United States (1244 publications, 54,456 citations), University of California system (136 publications, 5401 citations), and Yao Ke (49 publications, 838 citations), respectively. The top 100 ranked keywords are divided into four clusters through co-occurrence analysis: (1) secondary cataracts, (2) oxidative stress, (3) gene mutations and protein abnormalities, and (4) alteration of biological processes in lens epithelial cells. Further discussions on the four subtopics outline the research topics and trends. In conclusion, the specific mechanism of cataract formation remains a popular topic for future research and should be explored in greater depth.

Cataractogenesis and molecular pathways, with reactive free oxygen species as a common pathway

Slowing down or stopping the natural process of cataractogenesis is certainly a challenge for those who today propose an option other than surgery. Addressing the same problem in different ways constitutes a new approach to solving what is today the number one cause of reversible blindness worldwide. The technological revolution, as well as the advances in the biological sciences, allows us to conceive mechanisms never thought of before to stop the process that, as a common pathway, constitutes opacification of the crystalline lens. A new dawn for cataracts is coming through molecular, newly-discovered mechanisms. Cataractogenesis and molecular pathways have reactive free oxygen species as a common pathway. Surgical removal is today's gold standard, but perhaps not for much longer.

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.

Epigallocatechin gallate enhances human lens epithelial cell survival after UVB irradiation via the mitochondrial signaling pathway

The aim of the present study was to explore the mechanism underlying the ultraviolet B (UVB) irradiation-induced apoptosis of human lens epithelial cells (HLECs), and to investigate the protective effect of epigallocatechin gallate (EGCG) against the UVB-induced apoptosis of HLECs. HLECs were exposed to different concentrations of EGCG plus UVB (30 mJ/cm²). Cell viability was determined using the MTT assay. Furthermore, mitochondrial membrane potential (Δψm) and apoptosis were assessed by flow cytometry with JC-1 and Annexin V/PI staining, respectively. Moreover, the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as the levels of GSH, hydrogen peroxide (H₂O₂) and hydroxyl free radicals were determined using biochemical assay techniques. Reverse transcription-quantitative PCR and western blotting were used to detect the mRNA and protein expression levels of Bcl-2, Bax, cytochrome c, caspase-9 and caspase-3, respectively. The results revealed that UVB irradiation reduced the Δψm of HLECs and induced apoptosis. Notably, EGCG significantly attenuated the generation of H₂O₂ and hydroxyl free radicals caused by UVB irradiation in HLECs, and significantly increased CAT, SOD and GSH-Px activities, however, the GSH levels were not significantly increased. EGCG also reduced UVB-stimulated Bax, cytochrome c, caspase-9 and caspase-3 expression, and elevated Bcl-2 expression, suggesting that EGCG may possess free radical-scavenging properties, thus increasing cell viability. In conclusion, EGCG may be able to protect against UVB-induced HLECs apoptosis through the mitochondria-mediated apoptotic signaling pathway, indicating its potential application in clinical practice.

Inhibition of hepatocyte nuclear factor 1β contributes to cisplatin nephrotoxicity via regulation of nf-κb pathway

Cisplatin nephrotoxicity has been considered as serious side effect caused by cisplatin‐based chemotherapy. Recent evidence indicates that renal tubular cell apoptosis and inflammation contribute to the progression of cisplatin‐induced acute kidney injury (AKI). Hepatocyte nuclear factor 1β (HNF1β) has been reported to regulate the development of kidney cystogenesis, diabetic nephrotoxicity, etc However, the regulatory mechanism of HNF1β in cisplatin nephrotoxicity is largely unknown. In the present study, we examined the effects of HNF1β deficiency on the development of cisplatin‐induced AKI in vitro and in vivo. HNF1β down‐regulation exacerbated cisplatin‐induced RPTC apoptosis by indirectly inducing NF‐κB p65 phosphorylation and nuclear translocation. HNF1β knockdown C57BL/6 mice were constructed by injecting intravenously with HNF1β‐interfering shRNA and PEI. The HNF1β scramble and knockdown mice were treated with 30 mg/kg cisplatin for 3 days to induce acute kidney injury. Cisplatin treatment caused increased caspase 3 cleavage and p65 phosphorylation, elevated serum urea nitrogen and creatinine, and obvious histological damage of kidney such as fractured tubules in control mice, which were enhanced in HNF1β knockdown mice. These results suggest that HNF1β may ameliorate cisplatin nephrotoxicity in vitro and in vivo, probably through regulating NF‐κB signalling pathway.

Long non-coding RNA nuclear paraspeckle assembly transcript 1 protects human lens epithelial cells against H2O2 stimuli through the nuclear factor kappa b/p65 and p38/mitogen-activated protein kinase axis

Background

Long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (NEAT1) plays a regulatory role in many biological processes; however, its role in cataracts has yet to be illuminated. This study aimed to investigate the protective role of NEAT1 in hydrogen peroxide (H₂O₂)-treated human lens epithelial cells (HLECs) and its underlying molecular mechanism.

Methods

HLECs (SRA01/04) were treated with 300 µM H₂O₂ to mimic cataract in vitro. Cell viability was detected by performing an MTT assay and EdU staining. Flow cytometry was carried out to detect apoptosis of HLECs. DNA damage was examined using γ-H2A histone family member X staining. and reactive oxygen species (ROS) production was measured using 2’,7’dichlorofluorescin diacetate staining. The expression levels of lncRNA and proteins were detected with quantitative real-time polymerase chain reaction and western blot, respectively.

Results

The expression of NEAT1 was observed to be increased in H₂O₂-treated HLECs and age-related cataract (ARC) tissues. Knockdown NEAT1 strongly protected against H₂O₂-induced cell death and also regulated the expression of cleaved caspase-3, B-cell lymphoma 2, and Bcl-2-associated X protein. Further, knockdown NEAT1 also significantly suppressed H₂O₂-induced intracellular ROS production and malondialdehyde (MDA) content, but elevated the glutathione (GSH) activity of H₂O₂-treated cells. Also, it is demonstrated that si-NEAT1 greatly inhibited H₂O₂-induced phosphorylation of NF-кB p65 and p38 MAPK.

Conclusions

This study confirmed that knockdown NEAT1 attenuated H₂O₂-induced damage in HLECs, and inhibited the oxidative stress and apoptosis of HLECs via regulating nuclear factor-kappa B (NF-κB) p65 and p38 MAPK signaling. It may provide a potential target for clinical treatment of cataracts.

Amelioration of Lipopolysaccharide-Induced Nephrotic Proteinuria by NFAT5 Depletion Involves Suppressed NF-κB Activity

Idiopathic nephrotic syndrome (INS) is characterized by proteinuria, in which podocyte dysfunction associated with NF-κB-mediated inflammation plays an important role. The nuclear factor of activated T cells 5 (NFAT5) has been shown to enhance NF-κB activity. However, whether NFAT5 is associated with proteinuria remains uncharacterized. NFAT5 is upregulated in the glomeruli in lipopolysaccharide (LPS)-induced mouse nephrotic proteinuria, as well as in LPS-treated podocytes in vitro. In addition, NFAT5 depletion improves filtration barrier function of LPS-treated podocytes in vitro. Mechanistically, NFAT5 depletion suppresses NF-κB activation and downstream proinflammatory reaction in LPS-treated podocytes, and moreover, NF-κB inhibition improves filtration barrier function of LPS-treated podocytes, suggesting that the suppressed NF-κB activity at least partly accounts for NFAT5 depletion-improved filtration barrier function. Furthermore, in vivo, depletion of NFAT5 suppresses NF-κB activity and ameliorates nephrotic proteinuria in LPS-treated mice. These findings suggest a protective role of NFAT5 depletion against LPS-induced nephrotic proteinuria and relate it to the suppression of NF-κB activity.

Potential Role of Gene Regulator NFAT5 in the Pathogenesis of Diabetes Mellitus

Nuclear factor of activated T cells 5 (NFAT5), a Rel/nuclear factor- (NF-) κB family member, is the only known gene regulator of the mammalian adaptive response to osmotic stress. Exposure to elevated glucose increases the expression and nuclear translocation of NFAT5, as well as NFAT5-driven transcriptional activity in vivo and in vitro. Increased expression of NFAT5 is closely correlated with the progression of diabetes in patients. The distinct structure of NFAT5 governs its physiological and pathogenic roles, indicating its opposing functions. The ability of NFAT5 to maintain cell homeostasis and proliferation is impaired in patients with diabetes. NFAT5 promotes the formation of aldose reductase, pathogenesis of diabetic vascular complications, and insulin resistance. Additionally, NFAT5 activates inflammation at a very early stage of diabetes and induces persistent inflammation. Recent studies revealed that NFAT5 is an effective therapeutic target for diabetes. Here, we describe the current knowledge about NFAT5 and its relationship with diabetes, focusing on its diverse regulatory functions, and highlight the importance of this protein as a potential therapeutic target in patients with diabetes.

Alpha-Lipoic Acid Ameliorates Radiation-Induced Lacrimal Gland Injury through NFAT5-Dependent Signaling

Dry eye syndrome related to radiation therapy is relatively common and can severely impair a patient’s daily life. The nuclear factor of activated T cells 5(NFAT5) is well known for its osmoprotective effect under hyperosmolar conditions, and it also has immune-modulating functions. We investigated the role of NFAT5 and the protective effect of α-lipoic acid(ALA) on radiation-induced lacrimal gland (LG) injuries. Rats were assigned to control, ALA only, radiation only, and ALA administered prior to irradiation groups. The head and neck area, including the LG, was evenly irradiated with 2 Gy/minute using a photon 6-MV linear accelerator. NFAT5 expression was enhanced and localized in the LG tissue after irradiation and was related to cellular apoptosis. ALA had a protective effect on radiation-induced LG injury through the inhibition of NFAT5 expression and NFAT5-dependent signaling pathways. Functional radiation–induced damage of the LG and cornea was also restored with ALA treatment. NFAT5 expression and its dependent signaling pathways were deeply related to radiation-induced dry eye, and the condition was improved by ALA treatment. Our results suggest a potential role of NFAT5 and NF-κB in the proinflammatory effect in LGs and cornea, which offers a target for new therapies to treat dry eye syndrome.

Tanshinone IIA protects lens epithelial cells from H2 O 2 -induced injury by upregulation of lncRNA ANRIL

Tanshinone IIA is a lipophilic diterpene extracted from the Salvia miltiorrhiza bunge, possessing antiapoptotic and antioxidant activities. The purpose of this study was to explore the effects of Tanshinone IIA on age-related nuclear cataract. Human lens epithelial cell line SRA01/04 was subjected to H ₂ O ₂ to mimic a cell model of cataract. Cell Counting Kit-8 assay, flow cytometer, and reactive oxygen species (ROS) detection were performed to evaluate the effect of Tanshinone IIA pretreatment on SRA01/04 cells injured by H ₂ O ₂ . Besides, the real-time quantitative polymerase chain reaction was used to assess the expression of long noncoding RNA (lncRNA) antisense noncoding RNA in the INK4 locus (ANRIL). Western blot analysis was performed to detect the expression of core proteins involved in cell survival and nuclear factor-κB (NF-κB) pathway. H ₂ O ₂ significantly decreased SRA01/04 cells viability, whereas increased apoptosis and ROS generation. This phenomenon was coupled with the upregulated p53, p21, Bax, cleaved caspase-3, and the downregulated cyclinD1, CDK4, and Bcl-2. Tanshinone IIA pretreatment protected SRA01/04 cells against H ₂ O ₂ -induced injury. In the meantime, the expression of lncRNA ANRIL was upregulated by Tanshinone IIA. And, the protective effects of Tanshinone IIA on H ₂ O ₂ -stimulated SRA01/04 cells were abolished when lncRNA ANRIL was silenced. Moreover, the elevated expression of lncRNA ANRIL induced by Tanshinone IIA was abolished by BAY 11-7082 (an inhibitor of NF-κB). To conclude, Tanshinone IIA protects SRA01/04 cells from apoptosis triggered by H ₂ O ₂ . Tanshinone IIA confers its protective effects possibly via modulation of NF-κB signaling and thereby elevating the expression of lncRNA ANRIL.

BLM can regulate cataract progression by influencing cell vitality and apoptosis

Age-related cataract (ARC) is the most common cause of severe visual impairment and blindness. The precise mechanisms of ARC are not completely understood, but it is well accepted that oxidative damage plays an important role in the disease pathogenesis. BLM, the key enzyme of the double-strand break repair (DSBR) pathway, is part of a family of DNA unwinding enzymes and has a crucial role in multiple steps of the DNA recombination, replication and repair processes. We have recently shown that BLM-rs1063147 is initially associated with nuclear ARC in a cross-section study. Therefore, we wanted to study the effects of BLM on ARC progression. In ARC patients, BLM transcription in lens capsules was decreased, so did the BLM protein, and after UVB irradiation, BLM mRNA and protein levels were increased in SRA01/04 cells. Upon silencing BLM in SRA01/04 cells and rat lens, cell vitality and apoptosis were altered, and the rat lens opacification was considerable. In conclusion, BLM can regulate cataract progression by influencing cell vitality and apoptosis.