lncRNA H19 contributes to oxidative damage repair in the early age-related cataract by regulating miR-29a/TDG axis

LINC00942 Alleviates NaAsO2-induced Apoptosis by Promoting GSH Synthesis Through Targeting miR-214-5p

The mechanism of arsenic-induced liver toxicity is not fully understood. This study aimed to investigate the role of LINC00942 in arsenic-induced hepatotoxicity by regulating miR-214-5p. As the exposure dose of NaAsO2 gradually increases, cell viability, intracellular GSH content, ΔΨm, and the protein levels of GCLC and GCLM were reduced significantly. Apoptosis rate, ROS, and expression of apoptosis-related and NF-κB pathway proteins increased. The expression of LINC00942 was increased, while the expression of miR-214-5p was decreased. After suppressing LINC00942 levels, NaAsO2 exposure further decreased cell viability, intracellular GSH content, ΔΨm, GCLC protein, and miR-214-5p expression. The apoptosis rate, ROS, and apoptosis-related and NF-κB pathway proteins further increased. miR-214-5p is targeted and negatively regulated by LINC00942. After miR-214-5p was overexpressed, NaAsO2 further decreased cell viability, intracellular GSH content, ΔΨm, and GCLC protein expression compared to NaAsO2 exposure. The apoptosis rate, ROS, apoptosis-related and NF-κB pathway proteins p65, and IKKβ were higher than those exposed to NaAsO2. LINC00942 inhibitor along with miR-214-5p inhibitor combined with NaAsO2 treatment resulted in increased cell viability, GSH, Bcl-2, and GCLC protein expression and decreased apoptosis rate, apoptosis related, p65, IKKβ protein, and ΔΨm, as compared to the combined NaAsO2 and si LINC00942 group. NaAsO2 exposure induces oxidative damage and apoptosis in LX-2 cells by activating NF-κB and inhibiting GSH synthesis. During this process, the expression level of LINC00942 increases, targeting to reduce the level of miR-214-5p, then weakening the effect of NaAsO2 on NF-κB, thereby alleviating cellular oxidative damage and playing a protective role.

DNA hypermethylation of COL4A1 in ultraviolet-B-induced age-related cataract models in vitro and in vivo

AIM

To explore the DNA methylation of COL4A1 in ultraviolet-B (UVB)-induced age-related cataract (ARC) models in vitro and in vivo.

METHODS

Human lens epithelium B3 (HLEB3) cells and Sprague Dawley rats were exposure to UVB respectively. The MTT assay was utilized to evaluate cell proliferation. Flow cytometry was employed for analysis of cell apoptosis and cell cycle. COL4A1 expression in HLEB3 cells and anterior lens capsules were assessed using Western blot and reverse transcription-polymerase chain reaction (RT-PCR). The localization of COL4A1 in HLEB3 cells was determined by immunofluorescence. The methylation status of CpG islands located in COL4A1 promoter was verified using bisulfite-sequencing PCR (BSP). DNMTs and TETs mRNA levels was examined by RT-PCR.

RESULTS

UVB exposure decreased HLEB3 cells proliferation, while increased the apoptosis rate and cells were arrested in G0/G1 phase. COL4A1 expression was markedly inhibited in UVB treated cells compared to the controls. Hypermethylation status was detected in the CpG islands within COL4A1 promoter in HLEB3 cells subjected to UVB exposure. Expressions of DNMTs including DNMT1/2/3 were elevated in UVB treated HLEB3 cells compared to that in the controls, while expressions of TETs including TET1/2/3 showed the opposite trend. Results from the UVB treated rat model further confirmed the decreased expression of COL4A1, hypermethylation status of the CpG islands at promoter of COL4A1 and abnormal expression of DNMT1/2/3 and TET1/2/in UVB exposure group.

CONCLUSION

DNA hypermethylation of COL4A1 promoter CpG islands is correlated with decreased COL4A1 expression in UVB induced HLEB3 cells and anterior lens capsules of rats.

Role of non‑coding RNAs in UV‑induced radiation effects (Review)

Ultraviolet (UV) is divided into UVA (long-wave, 320-400 nm), UVB (middle-wave, 280-320 nm) and UVC (short-wave, 100-280 nm) based on wavelength. UV radiation (UVR) from sunlight (UVA + UVB) is a major cause of skin photodamage including skin inflammation, aging and pigmentation. Accidental exposure to UVC burns the skin and induces skin cancer. In addition to the skin, UV radiation can also impair visual function. Non-coding RNAs (ncRNAs) are a class of functional RNAs that do not have coding activity but can control cellular processes at the post-transcriptional level, including microRNA (miRNA), long non-coding RNA (lncRNA) and circulatory RNA (circRNA). Through a review of the literature, it was determined that UVR can affect the expression of various ncRNAs, and that this regulation may be wavelength specific. Functionally, ncRNAs participate in the regulation of photodamage through various pathways and play pathogenic or protective regulatory roles. In addition, ncRNAs that are upregulated or downregulated by UVR can serve as biomarkers for UV-induced diseases, aiding in diagnosis and prognosis assessment. Therapeutic strategies targeting ncRNAs, including the use of natural drugs and their extracts, have shown protective effects against UV-induced photodamage. In the present review, an extensive summarization of previous studies was performed and the role and mechanism of ncRNAs in UV-induced radiation effects was reviewed to aid in the diagnosis and treatment of UV-related diseases.

Identification and Verification of Ferroptosis-Related Genes in Keratoconus Using Bioinformatics Analysis

Objective

Keratoconus is a commonly progressive and blinding corneal disorder. Iron metabolism and oxidative stress play crucial roles in both keratoconus and ferroptosis. However, the association between keratoconus and ferroptosis is currently unclear. This study aimed to analyze and verify the role of ferroptosis-related genes (FRGs) in the pathogenesis of keratoconus through bioinformatics.

Methods

We first obtained keratoconus-related datasets and FRGs. Then, the differentially expressed FRGs (DE-FRGs) associated with keratoconus were screened through analysis, followed by analysis of their biological functions. Subsequently, the LASSO and SVM-RFE algorithms were used to screen for diagnostic biomarkers. GSEA was performed to explore the potential functions of the marker genes. Finally, the associations between these biomarkers and immune cells were analyzed. qRT‒PCR was used to detect the expression of these biomarkers in corneal tissues.

Results

A total of 39 DE-FRGs were screened, and functional enrichment analysis revealed that the DE-FRGs were closely related to apoptosis, oxidative stress, and the immune response. Then, using multiple algorithms, 6 diagnostic biomarkers were selected, and the ROC curve was used to verify their risk prediction ability. In addition, based on CIBERSORT analysis, alterations in the immune microenvironment of keratoconus patients might be associated with H19, GCH1, CHAC1, and CDKN1A. Finally, qRT‒PCR confirmed that the expression of H19 and CHAC1 was elevated in the keratoconus group.

Conclusion

This study identified 6 DE-FRGs, 4 of which were associated with immune infiltrating cells, and established a diagnostic model with predictive value for keratoconus.

Inhibition of miR-29a-3p Alleviates Apoptosis of Lens Epithelial Cells via Upregulation of CAND1

PURPOSE

Accumulated evidence has shown that microRNAs (miRNAs) are closely related to the pathogenesis and progression of senile cataracts. Here we investigate the effect of miR-29a-3p in cataractogenesis and determined the potential molecular mechanism involved.

METHODS

In this study, we constructed a selenite cataract model in rats and obtained the miRNAs related to cataracts by whole transcriptome sequencing. To investigate the effect and mechanism of miR-29a-3p on cataracts, we performed several in vivo and in vitro experiments, including CCK8 assay, flow cytometry, luciferase reporter assay, Edu assay, and western blot analysis.

RESULT

Sequencing data showed downregulation of miR-29a-3p in rats with selenite cataracts. Down-regulation of miR-29a-3p could promote lens epithelial cells (SRA01/04) proliferation and inhibit cell apoptosis, and miR-29a-3p silence could inhibit the development of cataracts. Additionally, CAND1 was a direct target gene for miR-29a-3p.

CONCLUSION

These data demonstrate that miR-29a-3p inhibits apoptosis of lens epithelial cells by regulating CAND1, which may be a potential target for senile cataracts.

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.

DCLRE1A Contributes to DNA Damage Repair and Apoptosis in Age-Related Cataracts by Regulating the lncRNA/miRNA/mRNA Axis

PURPOSE

Age-related cataract (ARC) is associated with the deregulation of transcription and defects in DNA repair in lens epithelial cells (LECs). DCLRE1A acted in DNA interstrand cross-links pathway to improve DNA replication and transcription. The aim of this study was to examined the further regulatory effect on DCLRE1A in the lncRNA-miRNA-mRNA network using a cell model of DCLRE1A overexpression (OE-DCLRE1A) in LECs.

METHODS

The expression level of DCLRE1A in ARC tissues and SRA01/04 cells after H2O2 treatment was measured as protein and mRNA by qRT-PCR and Western Blot(WB). CCK8, and TUNEL assays detected the change in cell viability and apoptosis, respectively. Furthermore, Immunofluorescence assays detect the expression of DNA damaged and repair marker proteins after OE-DCLRE1A. The global expression profiles of lncRNAs, miRNAs, and mRNAs were determined using high-throughput sequencing. KEGG and GO enrichment analysis disclose the possible function of differentially expressed (DE) lncRNA, miRNA, and mRNA.

RESULTS

The protein and mRNA of DCLRE1A were decreased in the anterior capsule of ARC and SRA01/04 cells treated by H2O2. OE-DCLRE1A improved damaged-DNA repair and enhanced cell viability against apoptosis after H2O2 treatment. Furthermore, we demonstrated the DE-molecules between the OE-DCLRE1A and control groups including 595 DE-lncRNAs, 221 DE-miRNAs, and 4718 DE-mRNAs. Next, bioinformatics analysis not only found that the DE-mRNAs are mainly involved in DNA repair-related signaling pathways after OE-DCLRE1A, but also screened two lncRNA-miRNA-mRNA networks focusing on DNA damage activated by OE-DCLRE1A, which involved 2 lncRNAs, 2 miRNAs, and 53 mRNAs.

CONCLUSION

We revealed that DCLRE1A activated the lncRNA/miRNA/DNA-repair network to take part in DNA repair processes, which not only represents a new regulatory mechanism employed by DCLRE1A but also uncovers the screening lncRNA may hold potential therapeutic values in ARC formation. However, these conclusions will need to be confirmed by future studies in vitro and in vivo models.

lncRNA TUG1 regulates Smac/DIABLO expression by competitively inhibiting miR-29b and modulates the apoptosis of lens epithelial cells in age-related cataracts

BACKGROUND

As one of the early discovered long non-coding RNAs (lncRNA), taurine upregulation gene 1 ( TUG1 ) has been widely expressed in a variety of tumors. Moreover, it promotes cell proliferation, differentiation, apoptosis, and migration. However, our understanding of its importance in the pathogenesis of cataracts remains limited. This study aimed to explore the mechanism by which lncRNA TUG1 mediates lens epithelial cell apoptosis in age-related cataracts (ARC) by regulating the microRNAs (miR-29b)/second mitochondria-derived activator of caspases axis, and to identify more non-surgical strategies for cataract treatment.

METHODS

The messenger RNA expression levels of TUG1 , miR-29b, and Smac were detected using quantitative real-time polymerase chain reaction in vivo and in vitro . The expression of the Smac protein was analyzed by Western blotting and immunofluorescence. Flow cytometry and cell counting kit-8 assays were used to detect the cell apoptosis and proliferation rates, respectively. The targeted regulatory relationship between lncRNA TUG1 , miR-29b, and Smac was verified by viral vector construction, co-transfection, nuclear and cytoplasmic separation, luciferase reporter assays, and RNA immunoprecipitation.

RESULTS

TUG1 and Smac were expressed at high levels in ARC and HLE-B3 cells treated with 200 μmol/L H 2 O 2 , whereas miR-29b expression was decreased. In vitro cell experiments confirmed that down-regulation of TUG1 could inhibit the apoptosis of lens epithelial cells. Mechanistically, Smac expression was negatively regulated by miR-29b. TUG1 competitively inhibited miR-29b expression and caused greater release of Smac. In addition, miR-29b partially reversed the effects of TUG1 on human lens epithelial cell line cells.

CONCLUSIONS

lncRNA TUG1 increases Smac expression and promotes apoptosis of lens epithelial cells in ARC by competitively inhibiting miR-29b. This mechanism is the cytological basis for ARC formation. Based on these results, the lncRNA TUG1/miR29b/Smac axis may be a new molecular pathway that regulates ARC development.

Roles of non-coding RNAs in eye development and diseases

The prevalence of ocular disorders is dramatically increasing worldwide, especially those that cause visual impairment and permanent loss of vision, including cataract, glaucoma, age-related macular degeneration, and diabetic retinopathy. Extensive evidence has shown that ncRNAs are key regulators in various biogenesis and biological functions, controlling gene expression related to histogenesis and cell differentiation in ocular tissues. Aberrant expression and function of ncRNA can lead to dysfunction of visual system and mediate progression of eye disorders. Here, we mainly offer an overview of the role of precise modulation of ncRNAs in eye development and function in patients with eye diseases. We also highlight the challenges and future perspectives in conducting ncRNA studies, focusing specifically on the role of ncRNAs that may hold expanded promise for their diagnostic and therapeutic applications in various eye diseases. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Comprehensive analysis of the prognostic value and biological function of TDG in hepatocellular carcinoma

Epigenetics plays an important role in the malignant progression of tumors, in which DNA methylation can alter genetic performance without altering the DNA sequence. As a key regulator demethylation, thymine-DNA glycosylase (TDG) has been reported to participate in malignant progression of multiple tumors. In this study, we demonstrate that TDG is highly expressed in hepatocellular carcinoma (HCC) and its high expression is closely related to the poor prognosis of patients. Decreasing TDG expression can significantly inhibit the malignant biological behavior of HCC cells. ABL proto-oncogene 1(ABL1) was identified as a downstream gene regulated by TDG demethylation. In addition, TDG can affect the Hippo signaling pathway through ABL1 to regulate HCC cell proliferation, apoptosis, invasion and migration. Overall, our study demonstrated that TDG reduces DNA methylation of ABL1, increases ABL1 protein expression, and affects the Hippo signaling pathway to regulate the malignant progression of HCC.

ceRNA network construction and identification of hub genes as novel therapeutic targets for age-related cataracts using bioinformatics

Background

The aim of this study is to investigate the genetic and epigenetic mechanisms involved in the pathogenesis of age-related cataract (ARC).

Methods

We obtained the transcriptome datafile of th ree ARC samples and three healthy, age-matched samples and used differential expression analyses to identify the differentially expressed genes (DEGs). The differential lncRNA-associated competing endogenous (ceRNA) network, and the protein-protein network (PPI) were constructed using Cytoscape and STRING. Cluster analyses were performed to identify the underlying molecular mechanisms of the hub genes affecting ARC progression. To verify the immune status of the ARC patients, immune-associated analyses were also conducted.

Results

The PPI network identified the FOXO1 gene as the hub gene with the highest score, as calculated by the Maximal Clique Centrality (MCC) algorithm. The ceRNA network identified lncRNAs H19, XIST, TTTY14, and MEG3 and hub genes FOXO1, NOTCH3, CDK6, SPRY2, and CA2 as playing key roles in regulating the pathogenesis of ARC. Additionally, the identified hub genes showed no significant correlation with an immune response but were highly correlated with cell metabolism, including cysteine, methionine, and galactose.

Discussion

The findings of this study may provide clues toward ARC pathogenic mechanisms and may be of significance for future therapeutic research.

Aberrant expression of COL4A1 in age-related cataract and its effect on cell proliferation, apoptosis and gene expression changes

AIM

To evaluate the regulation of the aberrant expression of collagen type IV alpha 1 chain (COL4A1) in the development of age-related cataract (ARC).

METHODS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot analysis were employed to evaluate the expression of COL4A1 in ARC patients and healthy controls. The proliferation, apoptosis, cell cycle and epithelial-mesenchymal transition (EMT) of human lens epithelial cell (HLE-B3) were further analyzed under the condition of COL4A1 gene silence. Alteration of gene expression at mRNA level after knockdown COL4A1 were also evaluated by qRT-PCR on HLE-B3 cells.

RESULTS

The aberrant expression of COL4A1 was identified a clinically associated with the ARC. Silencing of COL4A1 promoted the apoptosis and inhibited the proliferation of HLE-B3 by blocking the cell cycle. Moreover, COL4A1 gene silence didn't affect the cytoskeleton of HLE-B3 but down-regulated the Collagen type IV Alpha 2 Chain (COL4A2), paired box 6 (PAX6), procollagen-lysine 2-oxoglutarate 5-dioxygenases 1 (PLOD1) and procollagen-lysine 2-oxoglutarate 5-dioxygenases 2 (PLOD2) expression levels in HLE-B3 cells. Silencing the COL4A1 gene induced EMT of the HLE-B3 cells by promoting the transforming growth factor beta (TGF-β) expression.

CONCLUSION

Silencing of COL4A1 induces S-phase arrest, also inhibits the proliferation and enhance HLE-B3 apoptosis and EMT, and down-regulates the expression of COL4A2, PAX6, PLOD1 and PLOD2. Thus, the expression alteration of COL4A1 may play a critical role in the pathogenesis of ARC.

Exosomal microRNA-222-3p increases UVB sensitivity of lens epithelium cells by suppressing MGMT

BACKGROUND

Age-related cataract (ARC) is a leading cause of blindness worldwide with multiple pathogenic factors. Oxidative damage of lens epithelium cells (LECs) is one of the well-accepted pathogenesis of ARC which can be regulated by DNA repair genes (DRGs). The present research aimed to clarify the regulatory mechanism of exosomal microRNAs (miRNAs) on DRGs in LECs.

METHODS

The LECs oxidative damage model was established by UVB-irradiation on SRA01/04 (human lens epithelium cell line). Exosomes from UVB-irradiated cells (UVB-exo) and exosomes from normal control cells (NC-exo) were collected from the culture medium. To explore the functions of LECs exosomes, SRA01/04 were incubated with UVB-exo/NC-exo. Then, we detected SRA01/04 proliferation, viability and apoptosis respectively using 5'-ethynyl-2'-deoxyuridine (EdU), cell-counting kit-8 (CCK-8) and TdT-mediated dUTP Nick-End Labeling (TUNEL) assay. Next, the miRNA expression profiles of UVB-exo and NC-exo were identified by miRNA microarrays. RNA expression in exosomes, cells, and clinical samples was verified by qRT-PCR. The location and expression of MGMT and CD63 proteins were detected by immunofluorescence and western blot. The 3'UTR regulation of miR-222-3p to MGMT was verified by luciferase analyses.

RESULTS

MGMT down-regulated while miR-222-3p up-regulated in LECs sub-central anterior capsule from ARC lenses. MGMT and miR-222-3p expressions in central and peripheral LECs from anterior lens capsules were differential. UVB-exo can transport the up-regulated miR-222-3p from oxidative-damaged LECs to normal LECs, which could suppress MGMT expression and increase UVB sensitivity of LECs.

CONCLUSIONS

Findings on exosomal miRNA functions provided novel insights into pathogenesis of ARC. Exosomal miR-222-3p can be a potential target for prevention and cure of ARC.

Noncoding RNAs in cataract formation: star molecules emerge in an endless stream

For decades, research on the pathological mechanism of cataracts has usually focused on the abnormal protein changes caused by a series of risk factors. However, an entire class of molecules, termed non-coding RNA (ncRNA), was discovered in recent years and proven to be heavily involved in cataract formation. Recent studies have recognized the key regulatory roles of ncRNAs in cataracts by shaping cellular activities such as proliferation, apoptosis, migration and epithelial-mesenchymal transition (EMT). This review summarizes our current insight into the biogenesis, properties and functions of ncRNAs and then discusses the development of research on ncRNAs in cataracts. Considering the significant role of ncRNA in cataract formation, research on novel associated regulatory mechanisms is urgently needed, and the development of therapeutic alternatives for the treatment of cataracts seems promising.

Circ_HIPK3 Inhibits H2O2-Induced Lens Epithelial Cell Injury in Age-Related Cataract Depending on the Regulation of miR-495-3p/HDAC4 Pathway

Age-related cataract (ARC) is one of the most common chronic diseases. Circular RNA (circ)_HIPK3 is reported to be involved in the advancement of ARC, but its molecular mechanism has not been clarified. Our study provides a new perspective on the clinical treatment of ARC. Our data showed that the expression levels of circ_HIPK3 and histone deacetylase 4 (HDAC4) were downregulated, while microRNA (miR)-495-3p level was increased in ARC tissues and H₂O₂-induced SRA01/04 cells. Functional experiments showed that circ_HIPK3 and HDAC4 overexpression could inhibit H₂O₂-induced lens epithelial cell apoptosis and fibrosis. In terms of mechanism, we found that circ_HIPK3 could sponge miR-495-3p, miR-495-3p could target HDAC4. Besides, we confirmed that circ_HIPK3 sponged miR-495-3p to positively regulate HDAC4. Additionally, miR-495-3p overexpression or HDAC4 knockdown reversed the inhibition effect of circ_HIPK3 on H₂O₂-induced lens epithelial cell injury. In conclusion, our data showed that circ_HIPK3 suppressed H₂O₂-induced lens epithelial cell injury by regulating miR-495-3p/HDAC4 axis.

Long Non-Coding RNA H19 Prevents Lens Fibrosis through Maintaining Lens Epithelial Cell Phenotypes

The integrity of lens epithelial cells (LECs) lays the foundation for lens function and transparency. By contrast, epithelial-mesenchymal transition (EMT) of LECs leads to lens fibrosis, such as anterior subcapsular cataracts (ASC) and fibrotic forms of posterior capsule opacification (PCO). However, the underlying mechanisms remain unclear. Here, we aimed to explore the role of long non-coding RNA (lncRNA) H19 in regulating TGF-β2-induced EMT during lens fibrosis, revealing a novel lncRNA-based regulatory mechanism. In this work, we identified that lncRNA H19 was highly expressed in LECs, but downregulated by exposure to TGF-β2. In both human lens epithelial explants and SRA01/04 cells, knockdown of H19 aggravated TGF-β2-induced EMT, while overexpressing H19 partially reversed EMT and restored lens epithelial phenotypes. Semi-in vivo whole lens culture and H19 knockout mice demonstrated the indispensable role of H19 in sustaining lens clarity through maintaining LEC features. Bioinformatic analyses further implied a potential H19-centered regulatory mechanism via Smad-dependent pathways, confirmed by in vitro experiments. In conclusion, we uncovered a novel role of H19 in inhibiting TGF-β2-induced EMT of the lens by suppressing Smad-dependent signaling, providing potential therapeutic targets for treating lens fibrosis.

Identification and Integrated Analysis of the miRNA-mRNA Regulatory Network in Lens from an H2O2-Induced Zebrafish Cataract Model

PURPOSE

This study aimed to explore the regulatory mechanisms of age-related cataract (ARC) formation.

METHODS

Cataracts in zebrafish were induced by injecting hydrogen peroxide into the fish anterior chamber. The mRNA and miRNA expression profiles of the lens from H₂O₂-injected and PBS-injected zebrafishes were detected by RNA sequencing. The LIMMA package was applied to identify differentially expressed genes (DEGs). Gene Ontology categories were enriched by the R "cluster Profiler" package and Kyoto Encyclopedia of Genes and Genomes pathway enrichment was performed based on hypergeometric distribution using the R "phyper" function. The protein-protein interaction network of DEGs was built via the STRING. Target genes of differentially expressed miRNAs (DEmiRs) were predicted by miRanda. Furthermore, DEGs were selected as DEmiR targets and a DEmiR-DEG regulatory network was constructed via Cytoscape.

RESULTS

In total, 3689 DEGs (such as opn1mw4, LOC103908930, si:dkeyp-1h4.8, crispld1b, cyp1a, and gdpd3a) including 2478 upregulated and 1211 downregulated genes were identified. 177 DEmiRs (such as dre-miR-96-3p, dre-miR-182-5p, dre-miR-9-7-3p, and dre-miR-124-4-5p) including 108 upregulated and 69 downregulated miRNAs were detected. The DEGs are involved in cell death, DNA repair, and cell development-related pathways. A protein-protein interaction network including 79 node genes was constructed to explore the interactions of DEGs. Furthermore, a DEmiR-DEG regulatory network focusing on the DNA repair process was constructed, including 21 hub DEGs and 15 hub DEmiRs.

CONCLUSIONS

We identified several DEGs and constructed a miRNA-mRNA regulatory network related to the DNA repair process in a zebrafish cataract model. These genes participate in the oxidative stress response of lens epithelium cells and finally contribute to the formation of zebrafish cataracts. The hub DEGs and hub DEmiRs could be potential therapeutic targets for ARC.

XRCC5 downregulated by TRIM25 is susceptible for lens epithelial cell apoptosis

Exposure of the lens to UVB can lead to oxidative stress, which would result in age-related cataract (ARC) formation. In this study, we investigate the regulatory mechanism of tripartite motif containing 25 (TRIM25) in ARC. The protein level of TRIM25 was elevated in ARC specimens and UVB-exposed SRA01/04 cells. Bioinformatic analysis indicated that X-ray repair cross complementing 5 (XRCC5) might interact with TRIM25, and the interaction was validated via immunoprecipitation. TRIM25 interacted with XRCC5 and ubiquitinated it for degradation. Further studies showed that XRCC5 overexpression notably repressed UVB-induced apoptosis, while XRCC5 knockdown promoted apoptosis. Of note, ubiquitination of XRCC5 mediated by TRIM25 overexpression facilitated apoptosis. Attenuation of XRCC5 ubiquitination by mutant with substitution of lysine residues with arginine residues rescued its anti-apoptosis effect. Moreover, we observed that TRIM25-mediated XRCC5 degradation was reversed by proteasome inhibitor MG-132 or lysosome inhibitor 3-MA. In conclusion, TRIM25 mediates ubiquitination of XRCC5 to regulate the function and degradation of XRCC5, suggesting that interventions targeting TRIM25 might be a promising therapeutic strategy for ARC.

Role of long noncoding RNA KCNQ1 overlapping transcript 1/microRNA-124-3p/BCL-2-like 11 axis in hydrogen peroxide (H2O2)-stimulated human lens epithelial cells

Age-related cataract (ARC) is one of the most common causes of vision loss in aging people. This research analyzed the functions and mechanism of long noncoding RNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) in hydrogen peroxide (H₂O₂)-stimulated human lens epithelial cells (SRA01/04 cells) in ARC. SRA01/04 cells were stimulated with 200 µM H₂O₂ to establish oxidative damage in the ARC model. A MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and flow cytometry analysis were conducted to evaluate cell growth and apoptosis. The relevance between KCNQ1OT1 and microRNA (miR)-124-3p or miR-124-3p and BCL-2-like 11 (BCL2L11) was measured through Starbase and a dual luciferase reporter gene assay. The levels of KCNQ1OT1 and miR-124-3p were assessed via quantitative real-time polymerase chain reaction (qRT-PCR). We observed that KCNQ1OT1 was over-expressed and miR-124-3p was low-expressed in H₂O₂-stimulated SRA01/04 cells. KCNQ1OT1 interacted with miR-124-3p and negatively mediated its levels. In addition, KCNQ1OT1-siRNA reversed the effects of H₂O₂ on SRA01/04 cells, evidenced by enhanced cell viability, inhibited apoptotic cells, promoted Bcl-2 expression, and reduced Bax levels. Nevertheless, these observations were inverted after miR-124-3p inhibitor treatment. Likewise, miR-124-3p mimic had a protective effect on H₂O₂-stimulated SRA01/04 cells. Our data suggested that BCL2L11 targeted miR-124-3p directly. In summary, the data indicated that lncRNA KCNQ1OT1 down-regulation protected SRA01/04 cells from oxidative stress stimulated damage via the miR-124-3p/BCL2L11 pathway.

The lncRNA-AK046375 Upregulates Metallothionein-2 by Sequestering miR-491-5p to Relieve the Brain Oxidative Stress Burden after Traumatic Brain Injury

We previously discovered that traumatic brain injury (TBI) induces significant perturbations in long noncoding RNA (lncRNA) levels in the mouse cerebral cortex, and lncRNA-AK046375 is one of the most significantly changed lncRNAs after TBI. lncRNA-AK046375 overexpression and knockdown models were successfully constructed both in vitro and in vivo. In cultured primary cortical neurons and astrocytes, lncRNA-AK046375 sequestered miR-491-5p, thereby enhancing the expression of metallothionein-2 (MT2), which ameliorated oxidative-induced cell injury. In addition, upregulated lncRNA-AK046375 promoted the recovery of motor, learning, and memory functions after TBI in C57BL/6 mice, and the underlying mechanism may be related to ameliorated apoptosis, inhibited oxidative stress, reduced brain edema, and relieved loss of tight junction proteins at the blood-brain barrier in the mouse brain. Therefore, we conclude that lncRNA-AK046375 enhances MT2 expression by sequestering miR-491-5p, ultimately strengthening antioxidant activity, which ameliorates neurological deficits post-TBI.

miRNA and lncRNA Expression Networks Modulate Cell Cycle and DNA Repair Inhibition in Senescent Prostate Cells

Cellular senescence is a state of permanent growth arrest that arises once cells reach the limit of their proliferative capacity. It creates an inflammatory microenvironment favouring the initiation and progression of various age-related diseases, including prostate cancer. Non-coding RNAs (ncRNAs) have emerged as important regulators of cellular gene expression. Nonetheless, very little is known about the interplay of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) and how deregulation of ncRNA networks promotes cellular senescence. To investigate this, human prostate epithelial cells were cultured through different passages until senescent, and their RNA was extracted and sequenced using RNA sequencing (RNAseq) and microRNA sequencing (miRNA-seq) miRNAseq. Differential expression (DE) gene analysis was performed to compare senescent and proliferating cells with Limma, miRNA-target interactions with multiMiR, lncRNA-target interactions using TCGA data and network evaluation with miRmapper. We found that miR-335-3p, miR-543 and the lncRNAs H19 and SMIM10L2A all play central roles in the regulation of cell cycle and DNA repair processes. Expression of most genes belonging to these pathways were down-regulated by senescence. Using the concept of network centrality, we determined the top 10 miRNAs and lncRNAs, with miR-335-3p and H19 identified as the biggest hubs for miRNAs and lncRNA respectively. These ncRNAs regulate key genes belonging to pathways involved in cell senescence and prostate cancer demonstrating their central role in these processes and opening the possibility for their use as biomarkers or therapeutic targets to mitigate against prostate ageing and carcinogenesis.

Long Noncoding RNA H19: A Novel Therapeutic Target Emerging in Oncology Via Regulating Oncogenic Signaling Pathways

Long noncoding RNA H19 (H19) is an imprinting gene with only maternal expression that is involved in regulating different processes in various types of cells. Previous studies have shown that abnormal H19 expression is involved in many pathological processes, such as cancer, mainly through sponging miRNAs, interacting with proteins, or regulating epigenetic modifications. Accumulating evidence has shown that several oncogenic signaling pathways lead to carcinogenesis. Recently, the regulatory relationship between H19 and oncogenic signaling pathways in various types of cancer has been of great interest to many researchers. In this review, we discussed the key roles of H19 in cancer development and progression via its regulatory function in several oncogenic signaling pathways, such as PI3K/Akt, canonical Wnt/β-catenin, canonical NF-κB, MAPK, JAK/STAT and apoptosis. These oncogenic signaling pathways regulated by H19 are involved in cell proliferation, proliferation, migration and invasion, angiogenesis, and apoptosis of various cancer cells. This review suggests that H19 may be a novel therapeutic target for cancers treatment by regulating oncogenic signaling pathways.

Circular RNA circZNF292 regulates H2 O2 -induced injury in human lens epithelial HLE-B3 cells depending on the regulation of the miR-222-3p/E2F3 axis

Circular RNAs (circRNAs) play important roles in the pathogenesis of age-related cataract (ARC). CircRNA zinc finger protein 292 (circZNF292, hsa_circ_0004058) is downregulated in ARC lens capsules. Here, we focused on its precise roles in oxidative stress underlying the pathogenesis of ARC. CircZNF292, microRNA (miR)-222-3p, and E2F transcription factor 3 (E2F3) were quantified by quantitative real-time polymerase chain reaction or western blot. Cell viability was assessed by the cell counting kit-8 assay. Cell cycle distribution and apoptosis were detected by flow cytometry. The activities of superoxide dismutase, catalase, and malondialdehyde were measured using the corresponding assay kit. Targeted correlations among circZNF292, miR-222-3p, and E2F3 were verified by the dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Our data showed that circZNF292 was downregulated in ARC tissues and H₂ O₂ -treated human lens epithelial B3 (HLE-B3) cells. Increased expression of circZNF292 alleviated H₂ O₂ -induced cell viability suppression, apoptosis promotion, and oxidative stress enhancement. Mechanistically, circZNF292 directly targeted miR-222-3p, and circZNF292 regulated E2F3 expression through miR-222-3p. MiR-222-3p was a functional mediator of circZNF292 in modulating H₂ O₂ -induced injury in HLE-B3 cells. Furthermore, reduced level of miR-222-3p ameliorated H₂ O₂ -induced HLE-B3 cell damage by upregulating E2F3. Our present study demonstrated that increased expression of circZNF292 ameliorated H₂ O₂ -induced injury in HLE-B3 cells at least in part through the miR-222-3p/E2F3 axis, highlighting a novel insight into the involvement of circRNAs in the pathogenesis of ARC.

MicroRNA Let-7c-5p-Mediated Regulation of ERCC6 Disrupts Autophagic Flux in Age-Related Cataract via the Binding to VCP

Purpose: DNA damage contributes to the pathogenesis of age-related cataract (ARC) and is repaired through the nucleotide excision repair (NER) pathway, which includes ERCC6. Evidence has demonstrated that defective autophagy leads to lens organelle degradation and cataract. This study aimed to investigate the effects of ERCC6 on autophagy and determine its mechanisms in ARC.Methods: The clinical case-control study comprised 30 patients with ARC and 30 age-matched controls who received transparent lens extraction. Transmission electron microscopy was used to assess the ultrastructure of autophagic vesicles in lens anterior capsule tissues and lens epithelial cell line (SRA01/04). Real-time polymerase chain reaction and western blot analyses were performed to measure relative gene expression levels. Gene expression levels and localization were assessed by immunofluorescence. A coimmunoprecipitation assay was used to investigate the relationship between CSB which encoded by ERCC6 and VCP. ERCC6-siRNA and let-7 c-5p mimic were used to alter the expression of ERCC6 and let-7 c-5p.Results: Autophagy induction occurred in lens anterior capsule tissues of patients with ARC and in UVB-induced SRA01/04 cells, where the number of LC3B puncta was increased. Consistent with this result, the expression of beclin1 (BECN1) and LC3B, in addition to that of p62, was increased. Additionally, ERCC6 expression decreased, and silencing ERCC6 induced increases in the expression of BECN1, LC3B and p62. Moreover, CSB interacted with VCP, and let-7 c-5p induced dysregulation of autophagy by targeting ERCC6.Conclusion: In ARC, Let-7 c-5p-mediated downregulation of ERCC6 might prevent the degradation of autophagic vacuoles. CSB binds to VCP, inducing autophagosomes to combine with lysosomes and be degraded.

Long non-coding RNA KCNQ1OT1 promotes hydrogen peroxide-induced lens epithelial cell apoptosis and oxidative stress by regulating miR-223-3p/BCL2L2 axis

Many long non-coding RNAs (lncRNAs) can exert crucial roles in the pathogenesis of cataract, including lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1). We aimed to further elucidate the biological role and regulatory molecular mechanism of KCNQ1OT1 in cataract. The expression of KCNQ1OT1 and miR-223-3p and BCL2 like 2 (BCL2L2) was examined by qRT-PCR. Cataract cell model was constructed by treatment with hydrogen peroxide (H₂O₂) in lens epithelial cells (SRA01/04). SRA01/04 cell viability and cell apoptosis were tested using CCK-8 assay and flow cytometry, respectively. Western blot (WB) was performed to measure the levels of apoptosis-related proteins and BCL2L2 protein. The oxidative stress factors were analyzed by corresponding kits. The interaction between miR-223-3p and KCNQ1OT1 or BCL2L2 was validated by dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. We found that KCNQ1OT1 was upregulated in cataract anterior lens capsule samples and H₂O₂-induced SRA01/04 cells. Knockdown of KCNQ1OT1 suppressed H₂O₂-induced SRA01/04 cell apoptosis and oxidative stress. KCNQ1OT1 acted as a sponge of miR-223-3p. Inhibition of miR-223-3p could abate the function of KCNQ1OT1 silence in H₂O₂-treated SRA01/04 cells. Additionally, BCL2L2 was a direct target of miR-223-3p, and miR-223-3p weakened H₂O₂-induced SRA01/04 cell apoptosis and oxidative stress by targeting BCL2L2. Collectively, the data suggest a role for the KCNQ1OT1/miR-223-3p/BCL2L2 axis in cataract formation but the data was generated using an epithelial cell line.

Profiling and Integrated Analysis of the ERCC6-regulated circRNA-miRNA-mRNA Network in Lens Epithelial Cells

Purpose: To explore the regulatory role of ERCC6 in the circRNA-miRNA-mRNA network using a cellular ERCC6 overexpression model (OE-ERCC6) in lens epithelial cells.Methods: The expression profiles of circRNAs, miRNAs and mRNAs were determined by RNA-seq, and a regulatory circRNA-miRNA-mRNA network was constructed via bioinformatics. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used for the functional annotation of circRNA host genes, differentially expressed (DE) genes, and miRNA targets.Results: The DE molecules between the OE-ERCC6 and control groups included 269 circRNAs, 241 miRNAs and 3500 mRNAs. We validated 5 selected DE reads of circRNAs (hsa_circ_0001009, hsa_circ_0002024, hsa_circ_0004592, hsa_circ_0001900 and hsa_circ_0001017). Subsequent bioinformatics analysis revealed that the DE circRNAs are mainly involved in oxidative stress- and cell death-related signaling pathways. Finally, a circRNA-miRNA-mRNA network focusing on DNA damage and cell death, which involved 5 circRNAs, 13 miRNAs and 107 mRNAs, was constructed.Conclusion: We constructed a circRNA-miRNA-mRNA network that is regulated by ERCC6. DE circRNAs have the potential to become therapeutic targets related to the lens lesions observed in ARC. The establishment of related in vivo and in vitro models could be a future direction to confirm these hypotheses.

MiR-29a Alleviates High Glucose-induced Inflammation and Mitochondrial Dysfunction via Modulation of IL-6/STAT3 in Diabetic Cataracts

Background: This in vitro study was designed to reveal the role of miR-29a in high glucose-induced cellular injury through the modulation of IL-6/STAT3 in diabetic cataracts.Methods: The expression of miR-29a and STAT3 in the lens capsules of patients with or without diabetes was determined by RT-PCR. The levels of the IL-6 proinflammatory cytokine in the aqueous humor were detected by ELISA. HLE B-3 cells were cultured in normal glucose (NG; 5 mM) or high glucose (HG; 40 mM). After transfection with miR-29a, si-STAT3, or a negative control vector, the levels of IL-6 and STAT3 were detected. A CCK-8 assay was used to determine cell viability. We used flow cytometry to assess changes in reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), and apoptosis induced by oxidative stress. Western blotting was used to determine the expression of the oxidative injury markers superoxide dismutase (SOD) and malondialdehyde (MDA) and the apoptosis markers Bcl-2 and Bax.Results: Reduced miR-29a, increased STAT3 expression, and IL-6 release were demonstrated in the lens capsules and aqueous humor of patients with diabetes. The stimulation of apoptosis and the loss of MMP induced by HG were attenuated by transfection with a miR-29a mimic and si-STAT3. ROS production, increased MDA content, decreased SOD activity, and upregulation of the apoptotic proteins Bcl-2/Bax were also partially alleviated by miR-29a overexpression, which shows their roles in oxidative injury. Furthermore, transfection with a STAT3 overexpression vector reversed the effects of miR-29a.Conclusions: In conclusion, miR-29a mitigated HG-induced oxidative injury and exerted protective effects via IL-6/STAT3 signaling. Thus, miR-29a may be a potential therapeutic agent for diabetic cataracts.

TUG1 promotes retinoblastoma progression by sponging miR-516b-5p to upregulate H6PD expression

Background

Retinoblastoma (RB), depicted as an aggressive eye cancer, mainly occurs in infancy and childhood and is followed by high mortality and poor prognosis. Increasing evidence has revealed that long noncoding RNA taurine upregulated gene 1 (TUG1) is closely linked to the progression of diverse cancers. Nonetheless, the specific function and molecular regulatory mechanism of TUG1 in RB still need to be explored.

Methods

To explore the specific role of TUG1 in RB. TUG1 expression was detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2’-deoxyuridine (EdU), caspase-3, terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) and western blot assays were utilized to study the role of TUG1 in RB. The binding relation between miR-516b-5p and TUG1 or hexose-6-phosphate dehydrogenase/glucose 1-dehydrogenase (H6PD) was analyzed by luciferase reporter and RNA immunoprecipitation (RIP) assays.

Results

The expression of TUG1 was upregulated in RB cells. TUG1 knockdown repressed proliferation ability and promoted apoptosis ability of RB cells. Moreover, TUG1 could bind with miR-516b-5p, which targeted H6PD in RB. In addition, the expression of H6PD was negatively and positively regulated by miR-516b-5p and TUG1 in RB, respectively. Finally, H6PD overexpression could partially offset the effects of TUG1 deficiency on cell proliferation and apoptosis.

Conclusions

TUG1 promoted the development of RB by sponging miR-516b-5p to upregulate H6PD expression, which might provide a new thought for researching RB-related molecular mechanism.

CircMRE11A_013 binds to UBXN1 and integrates ATM activation enhancing lens epithelial cells senescence in age-related cataract

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

LncRNA H19 Suppresses Osteosarcomagenesis by Regulating snoRNAs and DNA Repair Protein Complexes

Osteosarcoma is one of the most frequent common primary malignant tumors in childhood and adolescence. Long non-coding RNAs (lncRNAs) have been reported to regulate the initiation and progression of tumors. However, the exact molecular mechanisms involving lncRNA in osteosarcomagenesis remain largely unknown. Li-Fraumeni syndrome (LFS) is a familial cancer syndrome caused by germline p53 mutation. We investigated the tumor suppressor function of lncRNA H19 in LFS-associated osteosarcoma. Analyzing H19-induced transcriptome alterations in LFS induced pluripotent stem cell (iPSC)-derived osteoblasts, we unexpectedly discovered a large group of snoRNAs whose expression was significantly affected by H19. We identified SNORA7A among the H19-suppressed snoRNAs. SNORA7A restoration impairs H19-mediated osteogenesis and tumor suppression, indicating an oncogenic role of SNORA7A. TCGA analysis indicated that SNORA7A expression is associated with activation of oncogenic signaling and poor survival in cancer patients. Using an optimized streptavidin-binding RNA aptamer designed from H19 lncRNA, we revealed that H19-tethered protein complexes include proteins critical for DNA damage response and repair, confirming H19's tumor suppressor role. In summary, our findings demonstrate a critical role of H19-modulated SNORA7A expression in LFS-associated osteosarcomas.

The cross-talk between signaling pathways, noncoding RNAs and DNA damage response: Emerging players in cancer progression

The DNA damage response (DDR) pathway's primary purpose is to maintain the genome structure's integrity and stability. A great deal of effort has done to understand the exact molecular mechanisms of non-coding RNAs, such as lncRNA, miRNAs, and circRNAs, in distinct cellular and genomic processes and cancer progression. In this regard, the ncRNAs possible regulatory role in DDR via modulation of key components expression and controlling repair signaling pathway activation is validated. Therefore, in this article, we will discuss the latest developments of ncRNAs contribution in different aspects of DNA repair through regulation of ATM-ATR, P53, and other regulatory signaling pathways.

Identification and Characterization of N6-Methyladenosine CircRNAs and Methyltransferases in the Lens Epithelium Cells From Age-Related Cataract

Purpose

To explore the involvement of N⁶-methyladenosine (m⁶A) modification in circular RNAs (circRNAs) and relevant methyltransferases in the lesion of lens epithelium cells (LECs) under the circumstances of age-related cataract (ARC).

Methods

LECs were collected from normal subjects and patients with cortical type of ARC (ARCC). M⁶A-tagged circRNAs and circRNAs expression were analyzed by m⁶A-modified RNA immunoprecipitation sequencing (m⁶A-RIP-seq) and RNA sequencing (RNA-seq). Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used to predict possible functions of the m⁶A-circRNAs. Expression of m⁶A-related methyltransferase and demethytransferase was measured by quantitative real-time polymerase chain reaction. Expression and location of AlkB homolog 5 RNA demethylase (ALKBH5), a key component of m⁶A demethytransferase, were determined by Western blot and immunostaining.

Results

All 4646 m⁶A peaks within circRNAs had different abundances, with 2472 enriched and 2174 subdued. The level of m⁶A abundance in total circRNAs was decreased in the LECs from ARCCs in comparison with the controls. We also found that the expression of highly m6A-tagged circRNAs was mostly decreased in comparison with non-m⁶A-tagged circRNAs. The bioinformatics analysis predicted the potential functions of m⁶A modified circRNAs and the relevant pathways that may be associated with m⁶A modified circRNAs. Among five major methyltransferases, ALKBH5 was significantly upregulated in LECs of ARCCs.

Conclusions

Our data provided novel evidence regarding the involvement of circRNAs m⁶A modifications in ARC. The altered expression of methyltransferases in lens tissue might selectively change the epigenetic profile of lens genome through regulating genes that host the circRNAs, thus enhance the susceptibility to ARC. The results might provide a new insight in the molecular target of ARC pathogenesis.

Platelet lysate induces chondrogenic differentiation of umbilical cord-derived mesenchymal stem cells by regulating the lncRNA H19/miR-29b-3p/SOX9 axis

Platelet lysate (PL) has been shown to induce chondrogenic differentiation of human umbilical cord‐derived mesenchymal stem cells (hUCMSCs). However, the underlying mechanism is still not clear. The aim of this study was to investigate whether long noncoding RNA H19 is involved in this process. hUCMSCs were isolated, identified and cultured in 5% PL‐supplemented chondrogenic differentiation medium. Chondrogenic differentiation was assessed by Alcian blue staining. The expressions of H19, miR‐29b‐3p, SRY‐related high‐mobility‐group box 9 (SOX9), collagen II and aggrecan were determined by quantitative real‐time PCR and western blot. The interaction between miR‐29b‐3p and H19 or SOX9 was analyzed by luciferase reporter assay. During PL‐induced chondrogenic differentiation of hUCMSCs, expressions of H19 and SOX9 were increased, whereas miR‐29b‐3p expression was decreased. H19 overexpression promoted, whereas H19 silencing attenuated the PL‐induced chondrogenic differentiation of hUCMSCs. SOX9 was identified as a direct target of miR‐29b‐3p, and H19 was observed to act as a sponge of miR‐29b‐3p to up‐regulate SOX9 expression. The chondrogenic differentiation‐promoting effect of H19 overexpression was negated when miR‐29b‐3p expression was up‐regulated by Lenti‐miR‐29b‐3p infection. In conclusion, PL induced chondrogenic differentiation of hUCMSCs by regulating the H19/miR‐29b‐3p/SOX9 axis.

Profiling of circular RNAs in age-related cataract reveals circZNF292 as an antioxidant by sponging miR-23b-3p

Age-related cataract (ARC) is one of the major causes of visual impairment and reversible blindness worldwide. Accumulating evidence has revealed that circular RNAs (circRNAs) are involved in multiple regulatory processes in various ocular diseases. However, the expression profile, regulatory roles, and underlying mechanisms of circRNAs in ARC remain largely unknown. Herein we deep-sequenced circRNAs of anterior lens capsules from normal and ARC lenses, and detected 23,787 candidate circRNAs. Of these, 466 were significantly differentially expressed, and a higher correlation in down-regulated circRNAs between ARC and diabetic cataract was observed compared with up-regulated ones. Subsequent bioinformatics analysis disclosed that certain differentially expressed circRNAs participated in oxidative stress and apoptosis-related signaling pathways in ARC. Notably, the level of circZNF292 was significantly decreased, while miR-23b-3p was significantly increased in ARC. The target region prediction and dual-luciferase reporter assays proved that circZNF292 acted as a competitive endogenous RNA to regulate the expression of anti-oxidative genes through competing with miR-23b-3p. Our results indicate that circZNF292, a down-regulated circRNA in the anterior lens capsule of ARC patients, may be involved in resistance to oxidative damage and apoptosis of lens epithelial cells by sponging miR-23b-3p, providing a potential target for prevention and treatment of ARC.

Long non‑coding RNA NONHSAT143692.2 is involved in oxidative DNA damage repair in the lens by regulating the miR‑4728‑5p/OGG1 axis

Age-related cataract (ARC) is the leading cause of blindness worldwide. Oxidative DNA damage is a biochemical feature of ARC pathogenesis. The present study investigated the role of long non-coding RNAs in the DNA repair of oxidative damage, partially the regulation of the DNA repair gene, 8-oxoguanine DNA glycosylase (OGG1), in lens affected by ARC. The ogg1 mutant zebrafish model was constructed to verify the role of ogg1 in the lens. A high-throughput lncRNA profiling was performed on human lens epithelial cells (LECs) following oxidative stress. The lncRNAs with the OGG1 target gene were analyzed for possible differentiated expression levels. The lens capsule samples of patients with ARC were collected to further verify the screening results. lncRNA was then overexpressed and knocked down in LECs to observe cell proliferation and apoptosis. The association between lncRNA, miRNA and the OGG1 mRNA 3′UTR were analyzed. The ogg1 mutant zebrafish developed more severe lens lesions following oxidative challenge. lncRNA NONHSAT143692.2 was distinctly expressed in various disease models. The knockdown of NONHSAT143692.2 downregulated the expression of OGG1 mRNA (P<0.001) and OGG1 protein (P<0.001), aggravated oxidative damage to LECs, increased apoptosis (P<0.001) and decreased cell proliferation (P<0.01). The overexpression of NONHSAT143692.2 reversed the above-mentioned outcomes. miR-4728-5p was predicted to bind to NONHSAT143692.2 and OGG1 mRNA 3′UTR. The overexpression of miR-4728-5p downregulated the expression of NONHSAT143692.2 (P<0.001), OGG1 mRNA (P<0.001) and OGG1 protein (P<0.001). The knockdown of miR-4728-5p reversed the above-mentioned outcomes. Overall, the findings of the present study demonstrate that the NONHSAT143692.2/miR-4728-5p/OGG1 axis may play an important role in the development of ARC. This novel concept may provide new insight into the molecular diagnosis and treatment of ARC.

Role of short-wavelength blue light in the formation of cataracts and the expression of caspase-1, caspase-11, Gasdermin D in rat lens epithelial cells: insights into a novel pathogenic mmechanism of cataracts

Background

With the popularity of blue-rich light-emitting diode (LED)-backlit display devices, our eyes are now exposed to more short-wavelength blue light than they were in the past. The goal of this study was to investigate the pathogenesis of cataracts after short-wavelength light exposure.

Methods

Sprague-Dawley (SD) rats were selected and randomly divided into a control group (10 rats each for the 4-, 8-, and 12-week groups) and an experimental group (10 rats each for the 4-, 8-, and 12-week groups). The rats in the experimental group were exposed to a short-wavelength blue LED lamp for 12 h per day. After exposure to the blue LED lamp, the rats were maintained in total darkness for 12 h, after which a 12-h light/dark cycle was resumed. The intensity of the lamp was 3000 lx. At the end of the short-wavelength blue LED lamp exposure (for 4, 8, and 12 weeks), the expression levels of caspase-1, caspase-11 and gasdermin D (GSDMD) were examined in rat lens epithelial cells (LECs) using qRT-PCR and Western blot analyses. An illuminance of 2500 lx was used to study the potential effect of blue LED light on HLE-B3 hLECs in vitro. AC-YVAD-CMK, a caspase-1 inhibitor, was used to confirm the pyroptosis of LECs by flow cytometry.

Results

After 6 weeks, cataracts developed in the experimental rats (4/20 eyes). The clarity of the lens gradually worsened with the duration of exposure. Twelve weeks later, all of the rat eyes had developed cataracts. The expression levels of caspase-1, caspase-11 and GSDMD at 4, 8, and 12 weeks were significantly higher in the samples from rats exposed to a short-wavelength blue LED lamp than in the samples from control rats (p<0.05). The proportions of double-positive hLECs were significantly increased in the 5-h and 10-h short-wavelength blue light exposure subgroups compared with the 5-h and 10-h caspase-1 inhibitor subgroups (p < 0.05).

Conclusion

The data indicate that pyroptosis plays a key role in cataract induction after short-wavelength blue light exposure. This study might provide new insights into a novel pathogenic mechanism of cataracts.

lncRNA MIAT increases cell viability, migration, EMT and ECM production in age-related cataracts by regulating the miR-181a/CTGF/ERK signaling pathway

Age-related cataract (ARC) is a common cause of blindness in elderly individuals. Long non-coding RNA (lncRNA) myocardial infarction associated transcript (MIAT) has been reported to participate in various biological processes in a number of diseases; however, the biological mechanism underlying MIAT during ARC is not completely understood. The expression levels of MIAT, microRNA (miR)-181a and connective tissue growth factor (CTGF) were measured by reverse transcription-quantitative PCR. The protein expression levels of CTGF, α-smooth muscle actin, fibronectin, collagen type I, ERK, phosphorylated (p)-ERK, mitogen-activated protein kinase (MEK), and p-MEK were detected by western blotting. Cell viability and migration were assessed using MTT and Transwell assays, respectively. Moreover, a dual-luciferase reporter assay was performed to investigate the interaction between miR-181a and MIAT or CTGF. MIAT and CTGF were upregulated, while miR-181a was significantly downregulated in ARC tissues compared with normal tissues. MIAT or CTGF knockdown decreased cell viability, migration, epithelial-mesenchymal transition and extracellular matrix production in TGF-β2-treated SRA01/04 cells. It was hypothesized that miR-181a may be sponged by MIAT and may target CTGF. Furthermore, the miR-181a inhibitor reversed the inhibitory effect of MIAT knockdown on the progression of TGF-β2-treated SRA01/04 cells. Moreover, CTGF knockdown also reversed MIAT overexpression-mediated progression of TGF-β2-treated SRA01/04 cells. In addition, MIAT and CTGF regulated the activity of the ERK signaling pathway. The results suggested that MIAT may regulate the progression of ARC via the miR-181a/CTGF/ERK signaling pathway, which may serve as a novel therapeutic target for ARC.

CircZNF609 enhances hepatocellular carcinoma cell proliferation, metastasis, and stemness by activating the Hedgehog pathway through the regulation of miR-15a-5p/15b-5p and GLI2 expressions

Emerging evidence has revealed that aberrantly expressed circular RNAs (circRNAs) play vital roles in tumorigenesis and progression of diverse human malignancies. Although an existing literature has elucidated the regulatory role of circZNF609 in breast cancer, the crucial function that circZNF609 exerted on hepatocellular carcinoma (HCC) remains unclear. Herein, we determined to explore the molecular mechanism of circZNF609 in HCC. In this study, circZNF609 was conspicuously overexpressed and featured with loop structure in HCC. Functional tests revealed that decreased expression of circZNF609 suppressed cell proliferation, metastasis and stemness, whereas induced cell apoptosis in HCC. Subsequent molecular mechanism assays indicated that circZNF609 contributed to HCC progression through activation of Hedgehog pathway. Moreover, circZNF609 was found to be negatively correlated with miR-15a-5p/15b-5p but positively correlated with GLI2. Moreover, there was a negative correlation between miR-15a-5p/15b-5p and GLI2. Rescue experiments testified that GLI2 overexpression could recover circZNF609 depletion-mediated function on HCC development while miR-15a-5p/15b-5p inhibition could partially rescue circZNF609 silencing-mediated effect on HCC progression. Final experiments in vivo further elucidated the suppressive function of circZNF609 knockdown on the tumorigenesis of HCC. Briefly, circZNF609 enhances HCC cell proliferation, metastasis, and stemness by activating the Hedgehog pathway through the regulation of miR-15a-5p/15b-5p and GLI2 expressions.

lncRNA H19 contributes to oxidative damage repair in the early age-related cataract by regulating miR-29a/TDG axis

Age‐related cataract (ARC) is caused by the exposure of the lens to UVB which promotes oxidative damage and cell death. This study aimed to explore the role of lncRNA H19 in oxidative damage repair in early ARC. lncRNAs sequencing technique was used to identify different lncRNAs in the lens of early ARC patients. Human lens epithelial cells (HLECs) were exposed to ultraviolet irradiation; and 8‐OHdG ELISA, Cell counting kit 8 (CCK8), EDU, flow cytometry and TUNEL assays were used to detect DNA damage, cell viability, proliferation and apoptosis. Luciferase assay was used to examine the interaction among H19, miR‐29a and thymine DNA glycosylase (TDG) 3'UTR. We found that lncRNA H19 and TDG were highly expressed while miR‐29a was down‐regulated in the three types of early ARC and HLECs exposed to ultraviolet irradiation, compared to respective controls. lncRNA H19 knockdown aggravated oxidative damage, reduced cell viability and proliferation, and promoted apoptosis in HLECs, while lncRNA H19 overexpression led to opposite effects in HLECs. Mechanistically, miR‐29a bound TDG 3'UTR to repress TDG expression. lncRNA H19 up‐regulated the expression of TDG by repressing miR‐29a because it acted as ceRNA through sponging miR‐29a. In conclusion, the interaction among lncRNA H19, miR‐29a and TDG is involved in early ARC. lncRNA H19 could be a useful marker of early ARC and oxidative damage repair pathway of lncRNA H19/miR‐29a/TDG may be a promising target for the treatment of ARC.