Down-Regulation of MicroRNA-133b Suppresses Apoptosis of Lens Epithelial Cell by Up-Regulating BCL2L2 in Age-Related Cataracts

Let-7c-3p suppresses lens epithelial-mesenchymal transition by inhibiting cadherin-11 expression in fibrotic cataract

Fibrotic cataract, including anterior subcapsular cataract (ASC) and posterior capsule opacification, always lead to visual impairment. Epithelial-mesenchymal transition (EMT) is a well-known event that causes phenotypic alterations in lens epithelial cells (LECs) during lens fibrosis. Accumulating studies have demonstrated that microRNAs are important regulators of EMT and fibrosis. However, the evidence explaining how microRNAs modulate the behavior and alter the cellular phenotypes of the lens epithelium in fibrotic cataract is insufficient. In this study, we found that hsa-let-7c-3p is downregulated in LECs in human ASC in vivo as well as in TGFβ2-induced EMT in vitro, indicating that hsa-let-7c-3p may participate in modulating the profibrotic processes in the lens. We then demonstrated that overexpression of hsa-let-7c-3p markedly suppressed human LEC proliferation and migration and attenuated TGFβ2-induced EMT and injury-induced ASC in a mouse model. In addition, hsa-let-7c-3p mediated lens fibrosis by directly targeting the CDH11 gene, which encodes cadherin-11 protein, an important mediator in the EMT signaling pathway. It decreased cadherin-11 protein expression at the posttranscriptional level but not at the transcriptional level by binding to a specific site in the 3-untranslated region (3'-UTR) of CDH11 mRNA. Moreover, blockade of cadherin-11 expression with a specific short hairpin RNA reversed TGFβ2-induced EMT in LECs in vitro. Collectively, these data demonstrated that hsa-let-7c-3p plays a clear role in attenuating ASC development and may be a novel candidate therapeutic for halting fibrosis and maintaining vision.

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.

FUNDC1 induces apoptosis and autophagy under oxidative stress via PI3K/Akt/mTOR pathway in cataract lens cells

OBJECTIVE

This purpose of the study is to explore the mRNA and protein expression of FUNDC1 in cataract cells and tissues, clarify the function and mechanism of FUNDC1 in cataract cells under oxidative stress.

METHODS

We used bioinformatic analysis to screen DEGs in cataract from GSE153933. The expression of FUNDC1 in cataract specimens and cells was measured by RT-qPCR and western blotting. MethPrimer was used to predict CpG island of FUNDC1 promoter. The methylation of FUNDC1 in cataract specimens and cells was determined by MSP assay. Flow cytometry assay was used to measure cell apoptosis in FUNDC1-knockdown and -overexpression SRA01/04 cells. The expression of LC3 was analyzed by immunofluorescence assay. The expression of apoptosis related proteins, autophagy and PI3K/Akt/mTOR related proteins was determined by western blotting.

RESULTS

The results of bioinformatic analysis revealed that FUNDC1 was upregulation in cataract. FUNDC1 was further high expression in SRA01/04 cells with H₂O₂ treatment whereas hypomethylation of FUNDC1 in cataract lens cells under oxidative stress. Knockdown of FUNDC1 decreased cell apoptosis and autophagy compared with negative control of SRA01/04 cells. While overexpression of FUNDC1 elevated cell apoptosis and autophagy compared to empty vector group in SRA01/04 cells. Mechanically, FUNDC1 reduced the phosphorylation of PI3K/Akt/mTOR pathway under oxidative stress in SRA01/04 cells.

CONCLUSION

Our study suggested that FUNDC1 deficiency restrains cell apoptosis and autophagy through inhibiting PI3K/Akt/mTOR signal pathway.

Knockdown of lncRNA TUG1 protects lens epithelial cells from oxidative stress-induced injury by regulating miR-196a-5p expression in age-related cataracts

Oxidative stress plays an important role in the pathogenesis of cataracts. Under oxidative stress, apoptosis of lens epithelial cells (LECs) is activated, which may cause lens opacity and accelerate the development of cataracts. Long non-coding RNA (lncRNA) and microRNA (miRNA/miR) are involved in cataracts. Previous studies have demonstrated that lncRNA taurine upregulated 1 (TUG1) promotes cell apoptosis induced by ultraviolet radiation by downregulating the expression of miR-421. However, the mechanism underlying TUG1 in age-related cataract remains to be elucidated. The present study aimed to investigate the effect of TUG1 in age-related cataracts and to determine the related underlying molecular mechanism. In the present study, the association between TUG1 and microRNA (miR)-196a-5p was predicted using StarBase and verified using a dual luciferase reporter assay in 293 cells. The LEC line SRA01/04 was exposed to 200 µM hydrogen peroxide (H₂O₂) for 24 h to establish an in vitro oxidative stress model. The mRNA expression levels of TUG1 and miR-196a-5p were analyzed using reverse transcription-quantitative PCR, whilst cell viability and apoptosis were determined using MTT and flow cytometry assays, respectively. The protein expression levels of cleaved caspase-3 and caspase-3 in SRA01/04 cells were determined using western blotting. The results of the present study revealed that TUG1 directly targeted miR-196a-5p expression. In addition, the expression levels of miR-196a-5p were downregulated in SRA01/04 cells following oxidative stress, whilst TUG1 expression was upregulated. Cell transfection with TUG1-small interfering RNA (siRNA) upregulated miR-196a-5p expression levels in SRA01/04 cells, which was reversed following co-transfection with the miR-196a-5p inhibitor. Transfection with TUG1-siRNA also reduced the levels of H₂O₂-induced oxidative damage in SRA01/04 cells, which was demonstrated by increased cell viability, reduced levels of apoptosis and downregulated cleaved caspase-3 levels. Conversely, transfection with the miR-196a-5p inhibitor reversed these effects aforementioned. Overexpression of miR-196a-5p reduced H₂O₂-induced oxidative damage in SRA01/04 cells. In conclusion, findings from the present study suggested that knocking down TUG1 expression may protect LECs from oxidative stress-induced apoptosis by upregulating the expression of miR-196a-5p.

MicroRNA-124 regulates lens epithelial cell apoptosis by affecting Fas alternative splicing by targeting polypyrimidine tract-binding protein in age-related cataract

BACKGROUND

Age-related cataract (ARC) is a primary cause of visual blindness worldwide. Lens epithelial cell (LEC) apoptosis, in which Fas plays an essential role, is a vital cytological basis for cataractogenesis. However, the regulatory mechanism of Fas-dependent LEC apoptosis is not well understood. This study aimed to investigate whether MicroRNA (miRNA)-124 can regulate LEC apoptosis by targeting polypyrimidine tract-binding protein (PTB) and thereby affecting Fas alternative splicing in ARC.

METHODS

Lens capsule samples from patients with ARC and cornea donors with a transparent lens were collected. HLE-B3 cells were cultured and treated with hydrogen peroxide (H₂ O₂ ) to establish an apoptosis model in LECs. The expression of miRNA-124, PTB, Fas, and Fas isoforms in tissues and cell lines was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blotting, polyacrylamide gel electrophoresis, and flow cytometry. The miRNA-124 mimic and inhibitor were transfected into HLE-B3 cells, and the effects of the miRNA-124/PTB/Fas pathway in LECs were assessed by analysis of their related targets.

RESULTS

High expression of miRNA-124 and membrane Fas (mFas) mRNA and decreased PTB expression were observed in the lens capsule samples. In cells undergoing H₂ O₂ -induced apoptosis, mFas expression was increased, accompanied by decreased PTB and increased miRNA-124 expression. Subsequently, miRNA-124 upregulation suppressed PTB expression, elevated the mFas level without affecting total Fas expression and promoted apoptosis; miRNA-124 downregulation exerted the opposite effects.

CONCLUSION

This study revealed that miRNA-124 promotes LEC apoptosis in ARC by upregulating mFas through targeted inhibition of PTB. Moreover, the identification of the miRNA-124/PTB/Fas pathway provides novel insight into Fas-dependent LEC apoptosis.

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-145 promotes miR-133b expression through c-myc and DNMT3A-mediated methylation in ovarian cancer cells

Ovarian cancer presents as malignant tumors in the female reproductive system with high mortality. MicroRNAs are involved in the progression of ovarian cancer; however, the regulatory relationship among miRs remains unclear. In our study, we verified that both miR-145 and miR-133b messenger RNA (mRNA) levels in ovarian cancer tissues were lower than in normal ovarian tissues, and their mRNA level in serum of patients with ovarian cancer was reduced. We demonstrated miR-145 targeted c-myc, and c-myc interacted physically with DNMT3A in ovarian cancer cells. We confirmed that c-myc recruited DNMT3A to the miR-133b promoter. miR-133b overexpression also inhibited target gene PKM2 expression along with the Warburg effect. Our results indicate that miR-145 inhibited the Warburg effect through miR-133b/PKM2 pathways, which may improve approaches to ovarian cancer diagnosis and treatment.

Let-7c-3p Regulates Autophagy under Oxidative Stress by Targeting ATG3 in Lens Epithelial Cells

Background

Oxidative stress is an important factor during age-related cataract formation. Apoptosis and autophagy induced by oxidative stress have been reported as key factors in age-related cataract. In our research, we investigated the role of let-7c-3p in the regulation of autophagy and apoptosis during the formation of age-related cataract. Material and Methods. Real-time PCR and western blot were employed to detect the expression of let-7c-3p in the tissues of age-related cataract. Human lens epithelial cells (LECs) were treated with H₂O₂ as an age-related cataract model. The extent of apoptosis was measured by flow cytometry and western blot. To detect autophagy, immunofluorescence was used to analyze the spot number of LC3, and western blot was used to detect the expression of LC3-II/I and ATG3. The molecular mechanisms of let-7c-3p regulating autophagy via ATG3 under oxidative stress were performed by a luciferase report gene assay and rescue experiment.

Results

Downregulation of let-7c-3p was found in the age-related cataract group aged >65 years relative to the age-related cataract group aged ≤65 years. Consistently, the expression of let-7c-3p was also lower under oxidative stress. The activities of LEC apoptosis and autophagy induced by oxidative stress were inhibited by let-7c-3p. By the bioinformatics database and the luciferase reporter assay, ATG3 was found to be a direct target of let-7c-3p. Let-7c-3p reduced the ATG3-mediated autophagy level, which was induced by oxidative stress in LECs.

Conclusion

Let-7c-3p inhibits autophagy by targeting ATG3 in LECs in age-related cataract.

RETRACTED: The protective role of microRNA-133b in restricting hippocampal neurons apoptosis and inflammatory injury in rats with depression by suppressing CTGF

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the integrity of the images in Figures 5, 6A and 8A, which appear to contain suspected duplications, as detailed here: https://pubpeer.com/publications/773D824533241B2186D16AA3FFCB3F and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. Additional suspected image duplications were detected within Figure 7A. Our analysis suggested these image anomalies represent either direct duplications of the entire image, or contain several repeated features between or within an image. The journal requested the corresponding author comment on these concerns and provide the raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

miR-23b-3p regulates apoptosis and autophagy via suppressing SIRT1 in lens epithelial cells

Age-related cataract is one of the prior causes of blindness and the incidence rates of cataract are even rising. Oxidative stress plays an important role in the pathogenesis of cataracts. Under oxidative stress, lens epithelial cell (LEC cell) apoptosis is activated, which might lead to the opacity of the lens and accelerate the progression of cataract development. Meanwhile, autophagy is also active to face oxidative stress. miRNAs have been reported to involve cataract. However, the underlying mechanism is not clear. The present study aimed to investigate the regulatory effect of miR23b-3p on apoptosis and autophagy in LEC cells under oxidative stress. The expression levels of miR-23b-3p were examined in age-related cataract tissues and LEC cells treated with hydrogen peroxide, showing that miR23b-3p expression levels were upregulated. Knockdown of miR23b-3p expression in LEC cells brought about apoptosis significantly decreased while autophagy significantly increased during hydrogen peroxide. We predicted microRNA miRNA-23b-3p might participate in regulating silent information regulator 1 (SIRT1) by bioinformatics database of TargetScan. Luciferase reporter assays confirmed that miRNA-23b-p could suppress SIRT1 expression by binding its 3'UTR. In addition, overexpression or knockdown of miR-23b-3p could decrease or increase SIRT1 expression, which indicated that Mir-23b-3p could suppress SIRT1 expression. In addition, enhanced SIRT1 could attenuate the regulation of cell apoptosis and autophagy induced by overexpression of miR-23b-3p. Taken together, our findings revealed that miR-23b-3p regulated apoptosis and autophagy via suppressing SIRT1 in LEC cell under oxidative stress, which could provide new ideas for clinical treatment of cataract.

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.

Effects of microRNA-195 on the Prognosis of Glioma Patients and the Proliferation and Apoptosis of Human Glioma Cells

Glioma is the most common and aggressive intracranial malignant tumor with poor prognosis. Acts as a tumor suppressor, microRNA-195 (miR-195) plays important roles in a variety of cancers. However, the expression of miR-195 and role of miR-195 in glioma are still not well understood. 186 patients with glioma were enrolled and the follow-up period ranges from 1 to 69 months. MiR-195 was exogenously transfected into human glioma U87 cell line. The cell proliferation assay (CCK-8), colony formation assay, cell cycle analysis and cell apoptosis analysis were examined to investigate miR-195 effect on U87 cells. MiR-195 levels were reversely correlated with pathological grades (r = -0.487, p = 0.003). For patients with low miR-195 levels, their median survival time was 15 months, whereas the median survival time in patients with high miR-195 levels was 56.53 months. Multi-factor Cox regression analysis showed that high level of miR-195 (Odds ratio (OR): 0.347, 95% CI: 0.121-0.992) was associated with decreased mortality risk of patients. Moreover, overexpression of miR-195 inhibits proliferation and colony formation, and induces apoptosis of U87 cells. MiR-195 could block the glioma cells in G0/G1 phase, reducing S phase cells and regulating apoptosis related proteins (Caspase-3, Caspase-8, Caspase-9 and Bcl-2). Downregulation of miR-195 was associated with poor prognosis in human glioma. MiR-195 acted as tumor suppressor through inhibiting cell proliferation and promoting cell apoptosis via blockade of cell cycle and regulation of apoptosis related proteins.

miR‑15a‑3p affects the proliferation, migration and apoptosis of lens epithelial cells

The present study investigated the effect of microRNA (miR)-15a-3p on the proliferation, migration and apoptosis of lens epithelial cells and its potential mechanism, in order to further elucidate the pathogenesis of age-related cataracts (ARCs). The HLE-B3 human lens epithelial cell line was transfected with miR-15a-3p mimic. Expression of the miR-15a-3p mimic was measured by fluorescence-based reverse transcription-quantitative polymerase chain reaction analysis. Cell proliferation, apoptosis, invasion and migration were investigated using MTT and plate clone formation assays, terminal deoxynucleotidyl transferase dUTP nick end labeling and flow cytometry, and a wound healing assay and Transwell assay, respectively. The protein expression levels of B-cell lymphoma 2 (BCL2) and myeloid cell leukemia sequence 1 (MCL1) were also compared between transfected and wild-type HLE-B3 cells by western blot analysis. The results showed that transfection with the miR-15a-3p mimic significantly suppressed the proliferation of HLE-B3 cells, induced cell apoptosis and increased the proportion of early apoptotic cells. The migration of HLE-B3 cells was significantly inhibited following transfection with miR-15a-3p mimic (P<0.01), whereas cell invasion was unaffected (P>0.05). In addition, reduced protein levels of BCL2 and MCL1 were observed in the miR-15a-3p mimic-transfected HLE-B3 cells (P<0.01). In conclusion, miR-15a-3p may suppress cell proliferation and migration, and induce cell apoptosis in lens epithelial cells through inhibiting the expression of BCL2 and MCL1, which contributes to the onset of ARCs.

miR-422a inhibits osteosarcoma proliferation by targeting BCL2L2 and KRAS

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. However, the underlying mechanism of osteosarcoma carcinogenesis and progression remains unknown. In the present study, we evaluated the expression profile of miRNAs in osteosarcoma tissues and the adjacent normal tissues. We found that the expression of miR-422a was down-regulated in osteosarcoma tissues and cell lines. In addition, we observed significantly elevated levels of repressive H3K9me3 and H3K27me3 and decreased active H3K4me3 on the promote region of miR-422a in osteosarcoma cells and clinical samples. Furthermore, up-regulation of miR-422a exhibited both in vitro and in vivo anti-tumor effects by inhibiting osteosarcoma cell growth and inducing apoptosis and cell cycle arrest. We also found that miR-422a targeted BCL2L2 and KRAS and negatively regulated their protein expression. Furthermore, restoration of miR-422a and knockdown of BCL2L2 and KRAS promoted apoptosis and induce cell cycle arrest in osteosarcoma cells. Taken together, the present study demonstrates that miR-422a may serve as a tumor suppressor in osteosarcoma via inhibiting BCL2L2 and KRAS translation both in vitro and in vivo. Therefore, miR-422a could be developed as a novel therapeutic target in osteosarcoma.

miR-211 regulates the antioxidant function of lens epithelial cells affected by age-related cataracts

AIM

To investigate the effects and mechanism of miR-211 in mediating the antioxidant function of lens epithelial cells affected by age-related cataracts.

METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect miR-211 expression in the anterior lens capsules of healthy people, the anterior lens capsules of patients with age-related cataracts, and human epithelial cell line (SRA01/04) cells exposed to oxidative stress. A 2', 7'-dichloro-fluorescein diacetate (DCFH-DA) probe was used to measure the levels of endogenous reactive oxygen species (ROS) in human lens epithelial cells (hLECs) exposed to 400 µmol/L H₂O₂ for 1h. SRA01/04 cells were transfected with either miR-211 mimics, mimic controls, miR-211 inhibitors or inhibitor controls. After 72h, these cells were exposed to 400 µmol/L H₂O₂ for 1h, then p53 and Bax mRNA expression were measured using RT-qPCR. p53 and Bax protein expression were also measured by Western blotting analysis. Finally, cell viability was assessed using an MTS assay.

RESULTS

Compared to the control group, expression of miR-211 in the anterior lens capsules of age-related cataract patients and in SRA01/04 cells exposed to oxidative stress was significantly increased (P<0.001). Levels of endogenous ROS were significantly elevated in hLECs exposed to oxidative stress (P<0.001). Compared to the mimic control group, the hLECs in the miR-211 mimic group expressed significantly higher levels of p53 and Bax mRNA and protein while cell viability was significantly reduced (P<0.001). Conversely, p53 and Bax mRNA and protein expression were significantly reduced in the miR-211 inhibitor group as compared to the control group, while the cells in this group had much higher levels of cell viability (P<0.001).

CONCLUSION

miR-211 is upregulated in the anterior lens capsules of age-related cataract patients. miR-211 decreased the antioxidative stress capacity of lens epithelial cells by upregulating p53 and Bax, while inhibiting cell proliferation and repair. This finding suggests that miR-211 may play a key role in the development of age-related cataracts.

miR-211 promotes lens epithelial cells apoptosis by targeting silent mating-type information regulation 2 homolog 1 in age-related cataracts

AIM

To detect the expression of miR-211 in age-related cataract tissue, explore the effects of miR-211 on lens epithelial cell proliferation and apoptosis, and identify its target gene.

METHODS

This study used real-time quantitative polymerase chain reaction (RT-qPCR) to measure the expression of miR-211 and its predicted target gene [silent mating-type information regulation 2 homolog 1 (SIRT1)] in 46 anterior lens capsules collected from age-related cataract patients. Human lens epithelial cell line (SRA01/04) cells were transfected with either miR-211 mimics, mimic controls, miR-211 inhibitors or inhibitor controls, 72h after transfection, miRNA and protein expression of SIRT1 were measured using RT-qPCR and Western blotting; then cells were exposed to 200 µmol/L H₂O₂ for 1h, whereupon cell viability was measured by MTS assay, caspase-3 assay was performed. Dual luciferase reporter assay was performed to verify the relationship between miR-211 of SIRT1.

RESULTS

Compared to the control group, expression of miR-211 was significantly increased (P<0.001), the miRNA and protein expression of SIRT1 were significantly decreased (P<0.001) in the anterior lens capsules of patients with age-related cataracts. Relative to the control group, SIRT1 miRNA and protein levels in the miR-211 mimic group were significantly reduced, cell proliferation activity significantly decreased, and caspase-3 activity was significantly increased (P<0.001). In the miR-211 inhibitor group, SIRT1 miRNA and protein expression were significantly increased, cell proliferation activity significantly increased, and caspase-3 activity was significantly decreased (P<0.001). A dual luciferase reporter assay confirmed that SIRT1 is a direct target of miR-211.

CONCLUSION

miR-211 is highly expressed in the anterior lens capsules of patients with age-related cataracts. By negatively regulating the expression of SIRT1, miR-211 promotes lens epithelial cell apoptosis and inhibits lens epithelial cell proliferation.

miR-24-p53 pathway evoked by oxidative stress promotes lens epithelial cell apoptosis in age-related cataracts

MicroRNA-24 (miR-24) serves an important role in cell proliferation, migration and inflammation in various types of disease. In the present study, the biological function and molecular mechanism of miR-24 was investigated in association with the progression of age-associated cataracts. To the best of our knowledge the present study is the first to report that the expression of miR-24 was significantly increased in human anterior lens capsules affected by age-associated cataracts as well as lens epithelial cells (LECs) exposed to oxidative stress. Overexpression of miR-24 induced p53 expression and p53 was verified as a direct target of miR-24. Overexpression of miR-24 enhanced LEC death by directly targeting p53. The present study revealed that oxidative stress induced the upregulation of miR-24 and enhanced LEC death by directly targeting p53. These results suggest that the miR-24-p53 signaling pathway is involved in a novel mechanism of age-associated cataractogenesis and miR-24 may be a useful therapeutic target for age-associated cataracts.

IFN-γ-induced microRNA-29b up-regulation contributes tokeratinocyte apoptosis in atopic dermatitis through inhibiting Bcl2L2

Recent evidence has suggested that microRNAs (miRNAs) may play a significant role in the pathogenesis of inflammatory skin conditions such as atopic dermatitis (AD). The aim of the present study was to evaluate the potential functions of miRNAs in AD and to identify the underlying mechanisms. We firstly analyzed miRNA expression in the skin lesions of patients with AD using microarray analysis. Validation analysis was performed in skin biopsy specimens and in serum using quantitative reverse transcription PCR (qRT-PCR). The relationship between microRNA-29b (miR-29b) and development of AD was further explored. Subsequently, gain- and loss-of-function studies were performed to determine the functions of miR-29b in interferon-γ (IFN-d)-induced keratinocytes (KCs) apoptosis. Further bioinformatics analysis and luciferase reporter assays were performed to predict its target genes, then the effects of miR-29b on the expression of BCL2-like2 (Bcl2L2) were investigated using qRT-PCR and western blot analysis. Finally, KCs were transfected with miR-29b mimics or Bcl2L2 siRNA (si-Bcl2L2) to explore the mechanism by which miR-29b plays in the pro-apoptotic roles in IFN-γ-treated keratinocytes. The miR-29b was found to be one of the most significantly up-regulated miRNAs in the skin lesions of patients with AD, as compared with healthy control and its expression was statistically associated with the development of AD. We, therefore, selected miR-29b as a candidate miRNA and investigated its function. Our in vitro data showed that the keratinocytes apoptosis induced by IFN-duced by IFN-ptosis induced by IFN-vestigated its function. Our stically associated with the deve particular, we identified Bcl2L2 as a direct target of miR-29b. More importantly, siRNA-induced knockdown of Bcl2L2 attenuated the protective effects of miR-29b inhibition on keratinocytes apoptosis. These results suggested that miR-29b knockdown may play an important role in preventing cell apoptosis in IFN-cktreated keratinocytes, and these effects might be partially through regulation of Bcl2L2. These findings revealed that the miR-29b/Bcl2L2 regulatory axis was involved in the pathogenesis of AD and suggested that knockdown of miR-29b might be a novel therapeutic target for AD.