LncRNA HOTAIR mediates TGF-β2-induced cell growth and epithelial-mesenchymal transition in human lens epithelial cells

Effects of Angiogenic Factors on the Epithelial-to-Mesenchymal Transition and Their Impact on the Onset and Progression of Oral Squamous Cell Carcinoma: An Overview

High levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF)-2 and angiopoietin (ANG)-2 are found in tissues from oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs). As might be expected, VEGF, FGF-2, and ANG-2 overexpression parallels the development of new blood and lymphatic vessels that nourish the growing OPMDs or OSCCs and provide the latter with metastatic routes. Notably, VEGF, FGF-2, and ANG-2 are also linked to the epithelial-to-mesenchymal transition (EMT), a trans-differentiation process that respectively promotes or exasperates the invasiveness of normal and neoplastic oral epithelial cells. Here, we have summarized published work regarding the impact that the interplay among VEGF, FGF-2, ANG-2, vessel generation, and EMT has on oral carcinogenesis. Results from the reviewed studies indicate that VEGF, FGF-2, and ANG-2 spark either protein kinase B (AKT) or mitogen-activated protein kinases (MAPK), two signaling pathways that can promote both EMT and new vessels' formation in OPMDs and OSCCs. Since EMT and vessel generation are key to the onset and progression of OSCC, as well as to its radio- and chemo-resistance, these data encourage including AKT or MAPK inhibitors and/or antiangiogenic drugs in the treatment of this malignancy.

Pharmacological roles of lncRNAs in diabetic retinopathy with a focus on oxidative stress and inflammation

Diabetic retinopathy (DR) is a complication caused by abnormal glucose metabolism, which affects the vision and quality of life of patients and severely impacts the society at large.DR has a complex pathogenic process. Evidence from multiple studies have shown that oxidative stress and inflammation play pivotal roles in DR.Additionally, with the rapid development of various genetic detection methods, the abnormal expression of long non-coding RNAs (lncRNAs) have been confirmed to promote the development of DR.Research has demonstrated the potential of lncRNAs as ideal biomarkers and theranostic targets in DR. In this narrative review, we will focus on the research results on mechanisms underlying DR, list lncRNAs confirmed to be closely related to these mechanisms, and discuss their potential clinical application value and limitations.

Regulation of the Inflammatory Response, Proliferation, Migration, and Epithelial-Mesenchymal Transition of Human Lens Epithelial Cells by the lncRNA-MALAT1/miR-26a-5p/TET1 Signaling Axis

Background

The ocular inflammatory microenvironment has been reported to be closely associated with the occurrence and progression of highly myopic cataract (HMC). Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) could alter the biological properties of mammalian cells by modulating the expression of inflammatory mediators; therefore, it may contribute to the development of HMC.

Objective

To investigate the function of MALAT1 in the inflammatory response, proliferation, migration, and epithelial-mesenchymal transition (EMT) of inflammatory and injured human lens epithelial cells (HLECs) and to reveal the underlying molecular signals.

Methods

Patients with HMC and age-related cataract (ARC) with an axial length of more than 26 mm were selected, and the anterior capsular tissue was obtained during cataract surgery. TNF-α (20 ng/mL) was chosen to induce inflammatory damage in HLECs to simulate the inflammatory microenvironment in HMC eyes. Specific siRNAs, inhibitors, and mimics were used to suppress or enhance the functions of MALAT1 and miR-26a-5p. RT-qPCR and Western blot analysis were performed to measure gene and protein expression, respectively.

Results

The expression of MALAT1 and the inflammatory mediators IL-6, MMP-2, and MMP-9 were significantly higher in HMC anterior capsule tissues than in ARC. TNF-α treatment increased the expression of MALAT1, while it also promoted the proliferation, migration, and EMT of HLECs. MALAT1 interference decreased the expression of IL-6 and MMP-2 and inhibited the aforementioned processes. Furthermore, MALAT1 negatively regulated the expression of miR-26a-5p and then promoted TET1 expression. TET1 was identified as a direct target of miR-26a-5p, and the promoting effect of MALAT1 on TET1 expression could be reversed by miR-26a-5p mimics.

Conclusion

The inflammatory environment and MALAT1 expression could be reciprocally induced in HLECs. MALAT1 may act as a ceRNA via the "sponge" miR-26a-5p and target TET1 to regulate the inflammatory response, proliferation, migration, and EMT processes in HLECs.

Long noncoding RNA (lncRNA) HOTAIR: Pathogenic roles and therapeutic opportunities in gastric cancer

Gastric cancer is one of the first malignant cancers in the world and a large number of people die every year due to this disease. Many genetic and epigenetic risk factors have been identified that play a major role in gastric cancer. HOTAIR is an effective epigenetic agent known as long noncoding RNA (lncRNA). HOTAIR has been described to have biological functions in biochemical and cellular processes through interactions with many factors, leading to genomic stability, proliferation, survival, invasion, migration, metastasis, and drug resistance. In the present article, we reviewed the prognostic value of the molecular mechanisms underlying the HOTAIR regulation and its function in the development of Gastric Cancer, whereas elucidation of HOTAIR–protein and HOTAIR–DNA interactions can be helpful in the identification of cancer processes, leading to the development of potential therapeutic strategies.

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.

Curcumin suppresses TGF-β2-induced proliferation, migration, and invasion in lens epithelial cells by targeting KCNQ1OT1/miR-377-3p/COL1A2 axis in posterior capsule opacification

BACKGROUND

Posterior capsule opacification (PCO) is a common complication after cataract surgery, which can lead to secondary loss of vision. Curcumin has been reported to play a suppressive role in PCO progression, and the potential molecular mechanism was explored in this study.

METHODS

Cell viability and proliferation were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay. Transwell assay and wound healing assay were performed to assess cell invasion and migration abilities. Western blot assay and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were conducted to measure the expression of proteins and RNAs. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to confirm the interaction between microRNA-377-3p (miR-377-3p) and KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) or collagen type I alpha 2 chain (COL1A2).

RESULTS

Curcumin dose-dependently alleviated transforming growth factor-β2 (TGF-β2)-induced proliferation, migration, and invasion in SRA01/04 cells. KCNQ1OT1 was up-regulated in PCO patients and TGF-β2-induced SRA01/04 cells. Curcumin-induced protective effects in TGF-β2-induced SRA01/04 cells were largely overturned by KCNQ1OT1 overexpression. KCNQ1OT1 directly interacted with miR-377-3p and negatively regulated its expression. miR-377-3p silencing overturned Curcumin-mediated protective effects in SRA01/04 cells upon TGF-β2 treatment. miR-377-3p directly interacted with the 3' untranslated region (3'UTR) of COL1A2. COL1A2 overexpression largely counteracted KCNQ1OT1 silencing-induced effects in TGF-β2-stimulated SRA01/04 cells. KCNQ1OT1 could up-regulate COL1A2 expression by sponging miR-377-3p in SRA01/04 cells.

CONCLUSION

In conclusion, Curcumin suppressed TGF-β2-induced malignant changes in lens epithelial cells by targeting KCNQ1OT1/miR-377-3p/COL1A2 axis.

TGF-β2-induced circ-PRDM5 regulates migration, invasion, and EMT through the miR-92b-3p/COL1A2 pathway in human lens epithelial cells

CircRNA circ-PRDM5 (PR/SET domain 5) (circ-PRDM5) is overexpressed in age-related cataracts. Nevertheless, the biological role of circ-PRDM5 in posterior capsule opacities (PCO) (a common complication after cataract surgery) is unclear. Human lens epithelial cells SRA01/04 (LECs) were stimulated with TGF-β2 (transforming growth factor beta-2) to mimic the PCO model in vitro. Cell viability, migration, and invasion were determined by MTT, transwell, or wound-healing assays. Protein levels of EMT (epithelial-to-mesenchymal transition) markers and COL1A2 (collagen type I alpha 2 chain) were analyzed by western blotting (WB). Relative expression of circ-PRDM5, miR-92b-3p, and COL1A2 mRNA was analyzed by qRT-PCR. The targeting relationship was confirmed by dual-luciferase reporter and RIP assays. We observed that circ-PRDM5 and COL1A2 were upregulated in PCO tissues and TGF-β2-treated LECs, while miR-92b-3p was downregulated. Both circ-PRDM5 and COL1A2 knockdown impaired TGF-β2-induced LEC migration, invasion, and EMT. Also, circ-PRDM5 could adsorb miR-92b-3p to regulate COL1A2 expression. Furthermore, miR-92b-3p inhibitor offset circ-PRDM5 knockdown-mediated influence on migration, invasion, and EMT of LECs under TGF-β2 stimulation. Also, COL1A2 overexpression overturned the repressive influence of miR-92b-3p mimic on TGF-β2-induced LEC migration, invasion, and EMT. In summary, TGF-β2-induced circ-PRDM5 facilitated LEC migration, invasion, and EMT by adsorbing miR-92b-3p and increasing COL1A2 expression, offering new insights into the development of PCO.

TGF-β2-induced NEAT1 regulates lens epithelial cell proliferation, migration and EMT by the miR-26a-5p/FANCE axis

AIM

To explore the regulatory mechanism of nuclear paraspeckle assembly transcript 1 (NEAT1) in the pathogenesis of posterior capsule opacification (PCO).

METHODS

Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was executed to analyze NEAT1 and microRNA (miR)-26a-5p expression in transforming growth factor-beta 2 (TGF-β2)-disposed lens epithelial cells (LECs). The proliferation, cell cycle progression, apoptosis, and migration of TGF-β2-disposed LECs were evaluated. The relationship between NEAT1 or fanconi anemia (FA) complementation group E (FANCE) and miR-26a-5p was verified by dual-luciferase reporter assay.

RESULTS

TGF-β2 induced NEAT1 expression in LECs. NEAT1 inhibition accelerated apoptosis, cell cycle arrest, decreased proliferation, epithelial-mesenchymal transition (EMT), and migration of TGF-β2-disposed LECs. NEAT1 sponged miR-26a-5p to further regulate FANCE expression. Rescue experiments presented that miR-26a-5p downregulation overturned NEAT1 silencing-mediated impacts on TGF-β2-disposed LEC biological behaviors. Additionally, FANCE overexpression reversed miR-26a-5p mimic-mediated impacts on TGF-β2-disposed LEC biological behaviors.

CONCLUSION

TGF-β2-induced NEAT1 facilitates LEC proliferation, migration, and EMT by upregulating FANCE via sequestering miR-26a-5p.

Involvement of METTL3/m6Adenosine and TGFβ/Smad3 signaling on Tenon's fibroblasts and in a rabbit model of glaucoma surgery

Glaucoma filtration surgery (GFS) is a classic operation for the treatment of glaucoma, which is the second leading cause of blindness, and scar formation caused by excessive human Tenon's capsule fibroblasts (HTFs) activation is responsible for surgery failure. However, the mechanism underlying excessive HTFs activation is largely unknown. Studies have revealed that N⁶-methyladenosine (m⁶A), which is one of the most common posttranscriptional modifications, plays an important role in multiple types of cellular processes. First, we isolated and identified primary HTFs and found that transforming growth factor-β1 (TGF-β1) enhanced cell viability and promoted cell proliferation and extracellular matrix (ECM) deposition in HTFs. We subsequently found that TGF-β1 elevated the quantity of m⁶A and promoted the expression of m⁶A "writers", in the process from DNA to RNA, adenylate was methylated at the sixth N position by methylases methyltransferase-like 3 (METTL3). Furthermore, we demonstrated that METTL3 repression inhibited the promotion of cell viability, proliferation and ECM deposition in HTFs treated with TGF-β1. We then illustrated that increased METTL3 played a role by promoting Smad3 in TGF-β1-induced HTFs. We subsequently demonstrated that the METTL3/Smad3 regulatory axis was aberrantly expressed in the rabbit model of GFS. Thus, our study reveals that METTL3 indeed plays a role in modulating Smad3 in TGF-β1-induced HTFs and further provides novel theoretical strategies based on METTL3 for the inhibition of scar formation after GFS.

The role of TGF-β2 in cartilage development and diseases

Transforming growth factor-beta2 (TGF-β2) is recognized as a versatile cytokine that plays a vital role in regulation of joint development, homeostasis, and diseases, but its role as a biological mechanism is understood far less than that of its counterpart, TGF-β1. Cartilage as a load-resisting structure in vertebrates however displays a fragile performance when any tissue disturbance occurs, due to its lack of blood vessels, nerves, and lymphatics. Recent reports have indicated that TGF-β2 is involved in the physiological processes of chondrocytes such as proliferation, differentiation, migration, and apoptosis, and the pathological progress of cartilage such as osteoarthritis (OA) and rheumatoid arthritis (RA). TGF-β2 also shows its potent capacity in the repair of cartilage defects by recruiting autologous mesenchymal stem cells and promoting secretion of other growth factor clusters. In addition, some pioneering studies have already considered it as a potential target in the treatment of OA and RA. This article aims to summarize the current progress of TGF-β2 in cartilage development and diseases, which might provide new cues for remodelling of cartilage defect and intervention of cartilage diseases.

There and Back Again: Hox Clusters Use Both DNA Strands

Bilaterian animals operate the clusters of Hox genes through a rich repertoire of diverse mechanisms. In this review, we will summarize and analyze the accumulated data concerning long non-coding RNAs (lncRNAs) that are transcribed from sense (coding) DNA strands of Hox clusters. It was shown that antisense regulatory RNAs control the work of Hox genes in cis and trans, participate in the establishment and maintenance of the epigenetic code of Hox loci, and can even serve as a source of regulatory peptides that switch cellular energetic metabolism. Moreover, these molecules can be considered as a force that consolidates the cluster into a single whole. We will discuss the examples of antisense transcription of Hox genes in well-studied systems (cell cultures, morphogenesis of vertebrates) and bear upon some interesting examples of antisense Hox RNAs in non-model Protostomia.

LncRNA HOTAIR promotes endometrial fibrosis by activating TGF-β1/Smad pathway

Homeobox transcript antisense RNA (HOTAIR) is a long non-coding RNA associated with a number of fibrosis-related diseases. The aim of this study was to investigate the specific role of HOTAIR in the development of endometrial fibrosis and to identify the molecular mechanisms underlying this process. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine the expression levels of HOTAIR in samples of intrauterine adhesion (IUA) tissue and in endometrial stromal cells (ESCs) that had been treated with transforming growth factor beta 1 (TGF-β1). Additionally, we transfected ESCs with either overexpression plasmid (pcDNA-HOTAIR) or silencing construct (si-HOTAIR) and then treated these cells with TGF-β1. We then performed RT-qPCR and western blot analysis, along with cell proliferation and apoptosis assays, to investigate the effects of HOTAIR on the transdifferentiation of ESCs into myofibroblasts. The results showed that the expression levels of HOTAIR were significantly elevated in IUA tissue and in ESCs that had been treated with TGF-β1. The overexpression of HOTAIR had a pro-fibrotic effect on ESCs, while the silencing of HOTAIR exerted an anti-fibrotic effect. Most importantly, the protein expression levels of p-Smad2 and p-Smad3 were significantly upregulated in TGF-β1-treated ESCs transfected with pcDNA-HOTAIR and were downregulated after transfection with si-HOTAIR constructs. These data indicate that HOTAIR promotes endometrial fibrosis by activating the TGF-β1/Smad signaling pathway, suggesting that the inhibition of HOTAIR may represent a promising therapeutic option for suppressing endometrial fibrosis.

LncRNA NEAT1 promotes proliferation, migration, invasion and epithelial-mesenchymal transition process in TGF-β2-stimulated lens epithelial cells through regulating the miR-486-5p/SMAD4 axis

Background

Abnormal proliferation, metastasis and epithelial-mesenchymal transformation (EMT) of lens epithelial cells (LECs) are direct factors of posterior capsular opacification (PCO). Nuclear enriched abundant transcript 1 (NEAT1) has been shown to promote cell proliferation, metastasis and EMT, but whether it affects the progression of PCO is unclear.

Methods

The expression of NEAT1, microRNA-486-5p (miR-486-5p) and Drosophila mothers against decapentaplegic 4 (SMAD4) was determined using quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation of cells was measured via 3-(4, 5-dimethyl-2 thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Transwell assay was employed to detect the migration and invasion of cells. The levels of EMT marker proteins, SMAD4 protein and transforming growth factor-β (TGF-β)/SMAD signaling pathway-related proteins were assessed by western blot (WB) analysis. Further, the relationship between miR-486-5p and NEAT1 or SMAD4 was confirmed by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and biotin-labeled RNA pull-down assay.

Results

NEAT1 is upregulated and miR-486-5p is downregulated in the posterior capsular tissues of PCO patients and TGF-β2-induced LECs. Interference of NEAT1 reverses the promoting effect of TGF-β2 on the proliferation, migration, invasion and EMT of LECs. MiR-486-5p can be sponged by NEAT1, and its inhibitor reverses the suppression effect of NEAT1 silencing on the progression of TGF-β2-induced LECs. SMAD4 functions as a target of miR-486-5p, and its overexpression recovers the inhibition effect of miR-486-5p overexpression on the progression of TGF-β2-induced LECs. The activity of the TGF-β/SMAD signaling pathway is regulated by the NEAT1/miR-486-5p/SMAD4 axis.

Conclusion

Our study shows that NEAT1 has a positive effect on the progression of PCO and is expected to become a new target for PCO treatment.

Long Noncoding RNA NEAT1 Regulates TGF-β2-Induced Epithelial-Mesenchymal Transition of Lens Epithelial Cells through the miR-34a/Snail1 and miR-204/Zeb1 Pathways

The aim of this study was to explore whether the long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1)/miR-34a/Snail1 and NEAT1/miR-204/Zeb1 pathways are involved in epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs). Primary human LECs (HLECs) were separated and cultured. Our results identified that TGF-β2 induces NEAT1 overexpression in a dose-dependent manner and a time-dependent manner. Additionally, TGF-β2 induced downregulation of E-cadherin and upregulation of fibronectin in primary HLECs through a NEAT1-dependent mechanism. Microarray analysis showed that NEAT1 overexpression inhibited the miR-34a and miR-204 levels in the LECs. The expression of miR-34a and miR-204 was decreased, and the levels of Snail1 and Zeb1 were elevated in human posterior capsule opacification- (PCO-) attached LECs and the LECs obtained from anterior subcapsular cataract (ASC) by quantitative RT-PCR (qRT-PCR). Mechanistic studies revealed that NEAT1 negatively regulates miR-34a or miR-204, and miR-34a or miR-204 directly targets Snail1 or Zeb1 by luciferase assay and RNA-binding protein immunoprecipitation assay, respectively. Overall, the NEAT1/miR-34a/Snail1 and NEAT1/miR-204/Zeb1 pathways are involved in TGF-β2-induced EMT of HLECs. In summary, TGF-β2 induces NEAT1 overexpression, which in turn suggests that NEAT1 acts as a ceRNA targeting Snail1 or Zeb1 by binding miR-34a or miR-204, and promotes the progression of EMT of LECs.

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.

LncRNA FEZF1-AS1 Promotes TGF-β2-Mediated Proliferation and Migration in Human Lens Epithelial Cells SRA01/04

Posterior capsule opacification (PCO) is a common complication after cataract surgery attributed to the proliferation and migration of postoperative residual lens epithelial cells (LECs). The long noncoding RNA (lncRNA) FEZ family zinc finger 1 antisense RNA 1 (FEZF1-AS1) promotes the proliferation and migration of multiple types of cancer cells. Here, we discovered that FEZF1-AS1 is markedly upregulated in TGF-β2-treated SRA01/04 cells. In addition, the proliferation and migration of SRA01/04 cells were enhanced following TGF-β2 treatment. FEZF1-AS1 knockdown inhibited the TGF-β2-induced proliferation and migration of SRA01/04 cells. Accordingly, FEZF1-AS1 overexpression promoted the TGF-β2-induced proliferation and migration of SRA01/04 cells. Finally, FEZF1-AS1 upregulated TGF-β2-induced SRA01/04 cell proliferation and migration via boosting FEZF1 protein levels. Our findings indicate that the dysregulation of FEZF1-AS1 participates in the TGF-β2-induced proliferation and migration of human lens epithelial cells (HLECs), which might be achieved, at least in part, through the induction of FEZF1 expression.