Long Noncoding RNA OIP5-AS1 Promotes Cell Apoptosis and Cataract Formation by Blocking POLG Expression Under Oxidative Stress

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Role of reactive oxygen species in epithelial-mesenchymal transition and apoptosis of human lens epithelial cells

AIM

To investigate the role of reactive oxygen species (ROS) in epithelial-mesenchymal transition (EMT) and apoptosis of human lens epithelial cells (HLECs).

METHODS

Flow cytometry was used to assess ROS production after transforming growth factor β2 (TGF-β2) induction. Apoptosis of HLECs after H2O2 and TGF-β2 interference with or without ROS scavenger N-acetylcysteine (NAC) were assessed by flow cytometry. The corresponding protein expression levels of the EMT marker α-smooth muscle actin (α-SMA), the extracellular matrix (ECM), marker fibronectin (Fn), and apoptosis-associated proteins were detected by using Western blotting in the presence of an ROS scavenger (NAC). Wound-healing and Transwell assays were used to assess the migration capability of HLECs.

RESULTS

TGF-β2 stimulates ROS production within 8h in HLECs. Additionally, TGF-β2 induced HLECs cell apoptosis, EMT/ECM synthesis protein markers expression, and pro-apoptotic proteins production; nonetheless, NAC treatment prevented these responses. Similarly, TGF-β2 promoted HLECs cell migration, whereas NAC inhibited cell migration. We further determined that although ROS initiated apoptosis, it only induced the accumulation of the EMT marker α-SMA protein, but not COL-1 or Fn.

CONCLUSION

ROS contribute to TGF-β2-induced EMT/ECM synthesis and cell apoptosis of HLECs; however, ROS alone are not sufficient for EMT/ECM synthesis.

Effects of lncRNA MTC on protein expression in skin fibroblasts of Liaoning Cashmere goat based on iTRAQ technique

Existing experiments have found a new intergenic lncRNA activated by melatonin, which is called lncRNA MTC. However, the regulatory mechanism of lncRNA MTC in Liaoning Cashmere goat skin fibroblasts has not been clarified. Specific knockdown of lncRNA MTC inhibits cell proliferation and increases apoptosis. iTRAQ reagent was used for relative and absolute quantification of proteins in lncRNA MTC-KD and NC groups to evaluate changes in protein expression during dermal fibroblast development following lncRNA MTC deletion. A total of 5931 proteins were found in Liaoning Cashmere goat skin fibroblasts, of which 123 were differentially expressed, including 32 up-regulated proteins and 91 down-regulated proteins. Of the 91 down-regulated proteins, 32 act mainly through related pathways (e.g., cell cycle, mitochondrial function, ribosomal structure, vesicular transport, cytoskeletal components and skin morphogenesis). LncRNA MTC facilitates the proliferation of Liaoning Cashmere goat skin fibroblasts by regulating ITGB5, TlN2, CTSS, POLG, RAP1B, CHAF1A, CDCA8 and other proteins involved in cell proliferation. The results of this study provide some candidate proteins for the in-depth investigation of the molecular mechanism of lncRNA MTC, which facilitates hair growth in cashmere goats and provides more insights into their regulatory networks and biochemical pathways.

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.

Cellular Localization of FOXO3 Determines Its Role in Cataractogenesis

The transcription factor forkhead box protein (FOX)-O3 is a core regulator of cellular homeostasis, stress response, and longevity. The cellular localization of FOXO3 is closely related to its function. Herein, the role of FOXO3 in cataract formation was explored. FOXO3 showed nuclear translocation in lens epithelial cells (LECs) arranged in a single layer on lens capsule tissues from both human cataract and N-methyl-N-nitrosourea (MNU)-induced rat cataract, also in MNU-injured human (H)-LEC lines. FOXO3 knockdown inhibited the MNU-induced increase in expression of genes related to cell cycle arrest (GADD45A and CCNG2) and apoptosis (BAK and TP53). H2 is highly effective in reducing oxidative impairments in nuclear DNA and mitochondria. When H2 was applied to MNU-injured HLECs, FOXO3 underwent cleavage by MAPK1 and translocated into mitochondria, thereby increasing the transcription of oxidative phosphorylation-related genes (MTCO1, MTCO2, MTND1, and MTND6) in HLECs. Furthermore, H2 mediated the translocation of FOXO3 from the nucleus to the mitochondria within the LECs of cataract capsule tissues of rats exposed to MNU. This intervention ameliorated MNU-induced cataracts in the rat model. In conclusion, there was a correlation between the localization of FOXO3 and its function in cataract formation. It was also determined that H2 protects HLECs from injury by leading FOXO3 mitochondrial translocation via MAPK1 activation. Mitochondrial FOXO3 can increase mtDNA transcription and stabilize mitochondrial function in HLECs.

Pancreatic Cancer-Derived Exosomes Promote the Proliferation, Invasion, and Metastasis of Pancreatic Cancer by the miR-3960/TFAP2A Axis

Background

The microRNAs (miRNAs) in cancer-derived exosomes have the ability to change tumor microenvironment. This study aims to investigate the role of miRNA in cancer-derived exosomes in pancreatic cancer (PC).

Methods

Based on the analysis of PC-derived and healthy exosomes by bioinformatics analysis and quantitative real-time PCR validation, the miR-3960 was identified to be the most significantly different miRNA, and TFAP2A proved as its potential target gene. Besides, the exosomes were isolated from PANC-1 cells and identified. After that, PANC-1 cells were treated with the isolated exosomes or transfected with miR-3960 mimics or si-TFAP2A, the effect of PC-derived exosomes, as well as the miR-3960/TFAP2A axis in PC cells, were assessed by the CCK-8, EDU staining, Transwell, cell colony formation, and flow cytometry assays. Furthermore, the effects of exosomes and the miR-3960/TFAP2A axis on PC tumor growth were observed in tumor-bearing mice by the measurement of tumor weight and volume, and hematoxylin-eosin staining. Moreover, the expressions of TFAP2A/PTEN/AKT signaling proteins were detected by Western blot.

Results

PC-derived exosomes were isolated successfully and proved to have promotion effects on the proliferation, metastasis, and invasion of PC cells both in vitro and tumor growth in vivo. Also, the PC-derived exosomes upregulated the TFAP2A, Bcl-2, and p-AKT/AKT protein levels, and inhibited PTEN and Bax levels and PANC-1 cell apoptosis. Overexpression of miR-3960 antagonized the promotion effect of exosomes on PC cells and the TFAP2A/PTEN/AKT signaling pathway, inhibiting the growth of tumors. Besides, si-TFAP2A enhanced the inhibitory effect of miR-3960 in PC.

Conclusion

MiR-3960 antagonizes the promotion effect of tumor-derived exosomes on the proliferation, invasion, and metastasis of PC via suppressing TFAP2A.

RNA-sequencing analysis reveals the long noncoding RNA profile in the mouse myopic retina

Aim: Myopia is a prevalent public health problem. The long noncoding RNA (lncRNA) mechanisms for dysregulated retinal signaling in the myopic eye have remained elusive. The aim of this study was to analyze the expression profiles and possible pathogenic roles of lncRNAs in mouse form-deprived myopia (FDM) retinas. Methods: A mouse FDM model was induced and retinas from the FDM right eyes and the contralateral eyes were collected for RNA sequencing. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and lncRNA-mRNA coexpression network analyses were conducted to explore the biological functions of the differentially expressed lncRNAs. In addition, the levels of differentially expressed lncRNAs in the myopic retinas were validated by quantitative real-time PCR (qRT-PCR). Fluorescence in situ hybridization (FISH) was used to detect the localization of lncRNAs in mouse retinas. Results: FDM eyes exhibited reduced refraction and increased ocular axial length compared to control fellow eyes. RNA sequencing revealed that there were 655 differentially expressed lncRNAs between the FDM and control retinas. Functional enrichment analysis indicated that the differentially expressed RNAs were mostly enriched in cellular processes, cytokine-cytokine receptor interactions, retinol metabolism, and rhythmic processes. Differentially expressed lncRNAs were validated by qRT-PCR. Additionally, RNA FISH showed that XR_384718.4 (Gm35369) localized in the ganglion cell (GCL) and inner nuclear layers (INL). Conclusion: This study identified the differential expression profiles of lncRNAs in myopic mouse retinas. Our results provide scientific evidence for investigations of myopia and the development of putative interventions in the future.

miR-125a-3p regulates apoptosis by suppressing TMBIM4 in lens epithelial cells

PURPOSE

To explore the regulatory effect of miR-125a-3p on lens epithelial cells (LECs) under ultraviolet radiation B (UVB) irradiation.

METHODS

The expression of miR-125a-3p in age-related cataract (ARC) specimens and cell models was detected by qRT-PCR. UVB was utilized to establish DNA damage model of LECs. Cell count kit-8 was applied in detecting cell viability. Cell apoptosis ratio was analyzed by flow cytometry. Dual luciferase reports were applied to analyze the mechanism between miRNA and target genes. Nanoparticle tracking analysis, and Western blot were used to identify whether the exosomes were typical exosomes.

RESULTS

miR-125a-3p was upregulated in ARC tissues and LECs treated with UVB. Knockdown of miR-125a-3p in LECs significantly decreased apoptosis and increased viability of UVB-irradiated LECs. We predicted that miR-125a-3p could regulate transmembrane Bax inhibitor motif containing 4 (TMBIM4) by the bioinformatics databases TargetScan, miRBase, and miRWalk. Luciferase reporter assays demonstrated that miR-125a-3p may suppress TMBIM4 protein translation by binding to 3'UTR of TMBIM4 mRNA. Overexpression of miR-125a-3p decreased TMBIM4, which suggested that miR-125a-3p could inhibit TMBIM4. Moreover, knockdown of TMBIM4 decreased cell viability and enhanced cell apoptosis during UVB irradiation. In addition, the exosome secretion of LECs irradiated by UVB was enhanced, and the expression of miR-125a-3p was high. Cell viability was significantly decreased, and cell apoptosis was increased during UVB-exos treatment.

CONCLUSION

This study indicated that miR-125a-3p regulated apoptosis by suppressing TMBIM4 in LECs under oxidative damage, providing a new idea for clinical therapeutic target of cataract.

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.

Hypoxic condition induced H3K27me3 modification of the LncRNA Tmem235 promoter thus supporting apoptosis of BMSCs

Bone marrow mesenchymal stem cells (BMSCs) have strong regenerative potential and show good application prospects for treating clinical diseases. However, in the process of BMSC transplantation for treating ischemic and hypoxic diseases, BMSCs have high rates of apoptosis in the hypoxic microenvironment of transplantation, which significantly affects the transplantation efficacy. Our previous studies have confirmed the key role of long non-coding RNA Tmem235 (LncRNA Tmem235) in the process of hypoxia-induced BMSC apoptosis and its downstream regulatory mechanism, but the upstream mechanism by which hypoxia regulates LncRNA Tmem235 expression to induce BMSC apoptosis is still unclear. Under hypoxic conditions, we found that the level of LncRNA Tmem235 promoter histone H3 lysine 27 trimethylation modification (H3K27me3) was significantly increased by CHIP-qPCR. Moreover, H3K27me3 cooperated with LncRNA Tmem235 promoter DNA methylation to inhibit the expression of LncRNA Tmem235 and promote apoptosis of BMSCs. To study the mechanism of hypoxia-induced modification of LncRNA Tmem235 promoter H3K27me3 in the hypoxia model of BMSCs, we detected the expression of H3K27 methylase and histone demethylase and found that only histone methylase enhancer of zeste homolog 2 (EZH2) expression was significantly upregulated. Knockdown of EZH2 significantly decreased the level of H3K27me3 modification in the LncRNA Tmem235 promoter. The EZH2 promoter region contains a hypoxia-responsive element (HRE) that interacts with hypoxia-inducible factor-1alpha (HIF-1α), which is overexpressed under hypoxic conditions, thereby promoting its overexpression. In summary, hypoxia promotes the modification of the LncRNA Tmem235 promoter H3K27me3 through the HIF-1α/EZH2 signaling axis, inhibits the expression of LncRNA Tmem235, and leads to hypoxic apoptosis of BMSCs. Our findings improve the regulatory mechanism of LncRNA Tmem235 during hypoxic apoptosis of BMSCs and provide a more complete theoretical pathway for targeting LncRNA to inhibit hypoxic apoptosis of BMSCs.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Changes in DNA methylation hallmark alterations in chromatin accessibility and gene expression for eye lens differentiation

Background

Methylation at cytosines (mCG) is a well-known regulator of gene expression, but its requirements for cellular differentiation have yet to be fully elucidated. A well-studied cellular differentiation model system is the eye lens, consisting of a single anterior layer of epithelial cells that migrate laterally and differentiate into a core of fiber cells. Here, we explore the genome-wide relationships between mCG methylation, chromatin accessibility and gene expression during differentiation of eye lens epithelial cells into fiber cells.

Results

Whole genome bisulfite sequencing identified 7621 genomic loci exhibiting significant differences in mCG levels between lens epithelial and fiber cells. Changes in mCG levels were inversely correlated with the differentiation state-specific expression of 1285 genes preferentially expressed in either lens fiber or lens epithelial cells (Pearson correlation r = − 0.37, p < 1 × 10^–42). mCG levels were inversely correlated with chromatin accessibility determined by assay for transposase-accessible sequencing (ATAC-seq) (Pearson correlation r = − 0.86, p < 1 × 10^–300). Many of the genes exhibiting altered regions of DNA methylation, chromatin accessibility and gene expression levels in fiber cells relative to epithelial cells are associated with lens fiber cell structure, homeostasis and transparency. These include lens crystallins (CRYBA4, CRYBB1, CRYGN, CRYBB2), lens beaded filament proteins (BFSP1, BFSP2), transcription factors (HSF4, SOX2, HIF1A), and Notch signaling pathway members (NOTCH1, NOTCH2, HEY1, HES5). Analysis of regions exhibiting cell-type specific alterations in DNA methylation revealed an overrepresentation of consensus sequences of multiple transcription factors known to play key roles in lens cell differentiation including HIF1A, SOX2, and the MAF family of transcription factors.

Conclusions

Collectively, these results link DNA methylation with control of chromatin accessibility and gene expression changes required for eye lens differentiation. The results also point to a role for DNA methylation in the regulation of transcription factors previously identified to be important for lens cell differentiation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13072-022-00440-z.

Long non-coding RNA OIP5-AS1 (Cyrano): A context-specific regulator of normal and disease processes

Long non-coding (lnc) RNAs have been implicated in a plethora of normal biological functions, and have also emerged as key molecules in various disease processes. OIP5-AS1, also commonly known by the alias Cyrano, is a lncRNA that displays broad expression across multiple tissues, with significant enrichment in particular contexts including within the nervous system and skeletal muscle. Thus far, this multifaceted lncRNA has been found to have regulatory functions in normal cellular processes including cell proliferation and survival, as well as in the development and progression of a myriad disease states. These widespread effects on normal and disease states have been found to be mediated through context-specific intermolecular interactions with dozens of miRNAs and proteins identified to date. This review explores recent studies to highlight OIP5-AS1's contextual yet pleiotropic roles in normal homeostatic functions as well as disease oetiology and progression, which may influence its utility in the generation of future theranostics.

EphA2 inhibits SRA01/04 cells apoptosis by suppressing autophagy via activating PI3K/Akt/mTOR pathway

This study attempted to determine the effect of EphA2 on H₂O₂-treated lens epithelial cells (SRA01/04) and the underlying mechanisms. MTT assay and flow cytometry were performed to assess cell viability and cell apoptosis. Western blot was carried out to examine the levels of proteins associated with apoptosis and autophagy. Our results revealed that EphA2 significantly elevated the reduced cell viability, and inhibited the increased cell apoptosis in H₂O₂-treated SRA01/04 cells, along with the significant up-regulated Bcl-2 and down-regulated Cleaved-caspase-3 and Bax protein levels, but which were all abolished by Rapa (autophagy activator). We also found that EphA2 significantly suppressed cell autophagy in H₂O₂-treated SRA01/04 cells. Additionally, EphA2 significantly up-regulated the protein levels of p-Akt and p-mTOR in H₂O₂-treated SRA01/04 cells, and the inhibition of Akt by MK-2206 and inhibition of mTOR by Rapa both obviously reversed EphA2-mediated the inhibition of autophagy in H₂O₂-treated SRA01/04 cells. In summary, these data demonstrated that EphA2 inhibited the apoptosis of SRA01/04 cells by inhibiting autophagy via activating PI3K/Akt/mTOR pathway.

LncRNA OIP5-AS1 inhibits ferroptosis in prostate cancer with long-term cadmium exposure through miR-128-3p/SLC7A11 signaling

Previous studies suggest that cadmium (Cd) is one of the causative factors of prostate cancer (PCa), but the effect of chronic Cd exposure on PCa progression remains unclear. Besides, whether long noncoding RNAs (lncRNAs) are involved in the regulation of prolonged exposure to Cd in PCa needs to be elucidated. In the present study, we found that the serum concentration of Cd in PCa patients was positively correlated with the Gleason score and tumor-node-metastasis (TNM) classification. To simulate chronic Cd exposure in PCa, we subjected PC3 and DU145 cells to long-term, low-dose Cd exposure and further examined tumor behavior. Functional studies identified that chronic Cd exposure promoted cell growth and ferroptosis resistance in vitro and in vivo. Furthermore, we found that lncRNA OIP5-AS1 expression was greatly elevated in PC3 and DU145 cells upon chronic Cd exposure. Dysregulation of OIP5-AS1 expression mediated cell growth and Cd-induced ferroptosis. Mechanistically, we demonstrated that OIP5-AS1 served as an endogenous sponge of miR-128-3p to regulate the expression of SLC7A11, a surrogate marker of ferroptosis. Moreover, miR-128-3p decreased cell viability by enhancing ferroptosis. Taken together, our data indicate that lncRNA OIP5-AS1 promotes PCa progression and ferroptosis resistance through miR-128-3p/SLC7A11 signaling.

EphA2 overexpression reduces H2O2-induced damage of lens epithelial cells

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

Hallmarks of lens aging and cataractogenesis

Lens homeostasis and transparency are dependent on the function and intercellular communication of its epithelia. While the lens epithelium is uniquely equipped with functional repair systems to withstand reactive oxygen species (ROS)-mediated oxidative insult, ROS are not necessarily detrimental to lens cells. Lens aging, and the onset of pathogenesis leading to cataract share an underlying theme; a progressive breakdown of oxidative stress repair systems driving a pro-oxidant shift in the intracellular environment, with cumulative ROS-induced damage to lens cell biomolecules leading to cellular dysfunction and pathology. Here we provide an overview of our current understanding of the sources and essential functions of lens ROS, antioxidative defenses, and changes in the major regulatory systems that serve to maintain the finely tuned balance of oxidative signaling vs. oxidative stress in lens cells. Age-related breakdown of these redox homeostasis systems in the lens leads to the onset of cataractogenesis. We propose eight candidate hallmarks that represent common denominators of aging and cataractogenesis in the mammalian lens: oxidative stress, altered cell signaling, loss of proteostasis, mitochondrial dysfunction, dysregulated ion homeostasis, cell senescence, genomic instability and intrinsic apoptotic cell death.

Kaempferol ameliorates the regulatory effects of PVT1/miR-214 on epithelial-mesenchymal transition through the PAK4/β-catenin axis in SRA01/04 cells

Aim: To investigate whether kaempferol exhibits a protective effect on high glucose-induced epithelial-mesenchymal transition (EMT) by mediating the PVT1/miR-214 and PAK4/β-catenin pathways in SRA01/04 cells. Methods & methods: qRT-PCR and western blot assays were used for gene and protein determination, and migration and invasion assays were conducted. A coimmunoprecipitation assay was used for determining protein interactions. Results: High glucose effectively upregulated PVT1 expression, downregulated miR-214 expression and promoted cell migration and invasion. Kaempferol attenuated high glucose-induced EMT by increasing PVT1 expression and decreasing miR-214 expression. PAK4 was identified as a direct target of miR-214. PAK4 overexpression could rescue the effects of PVT1 deficiency on SRA01/04 cells. Conclusion: Kaempferol ameliorated the regulatory effects of PVT1/miR-214 on high glucose-induced EMT through PAK4/β-catenin in SRA01/04 cells.

Long Non-coding RNA BTG3-7:1 and JUND Co-regulate C21ORF91 to Promote Triple-Negative Breast Cancer Progress

Background

Triple-negative breast cancer (TNBC) is a type of highly invasive breast cancer with poor prognosis. Recently, massive data reveal that long non-coding RNAs (lncRNAs) play important roles in cancer progress. Recently, although the role of lncRNAs in breast cancer has been well documented, few focused on TNBC. In this study, we aimed to systematically identify functional lncRNAs and to explore its molecular mechanism on TNBC progress.

Methods

The recurrence of lncRNAs and their target genes were validated with TNBC biopsies and cell lines. Total one hundred and thirteen TNBC biopsies, including nineteen patient-matched samples, were collected. The profile of TNBC-related lncRNAs and their target genes were characterized by RNA sequencing (RNA-seq) and bioinformatic analysis. Tumor specific lncRNAs, which also showed biological function correlated with TNBC, were identified as potential candidates; and the target genes, which regulated by the identified lncRNAs, were predicted by the analysis of expression correlation and chromosome colocalization. Cross bioinformatic validation was performed with TNBC independent datasets from the cancer genome atlas (TCGA). The biological functions and molecular mechanism were investigated in TNBC model cell lines by cell colony forming assay, flow cytometry assay, western-blot, RNA Fluorescence in situ Hybridization assay (RNA FISH) and chromatin immunoprecipitation-qPCR (ChIP-qPCR).

Results

Abundant Lnc-BTG3-7:1, which targets gene C21ORF91, was specifically observed in TNBC biopsies and cell lines. Knockdown of Lnc-BTG3-7:1 or C21ORF91 strongly inhibited cell proliferation, promoted cell apoptosis and cell cycle G1-arrested. Meanwhile, investigation of molecular mechanism indicated that Lnc-BTG3-7:1, cooperated with transcription factor JUND, cis-regulated the transcription of C21ORF91 gene, and down-regulation of Lnc-BTG3-7:1/C21ORF91 suppressed GRB2-RAS-RAF-MEK-ERK and GRB2-PI3K-AKT-GSK3β-β-catenin pathways.

Conclusions

In this study, we identified a TNBC specific lncRNA Lnc-BTG3-7:1, which sustained tumor progress. Up-regulation of Lnc-BTG3-7:1 promoted the transcription of oncogene C21ORF91 and activated PI3K-AKT-GSK3β-β-catenin and MAPK pathways. Taken together, our results not only identified a biomarker for diagnosis but also provided a potential therapeutic target against TNBC.