Circular RNA-ZBTB44 regulates the development of choroidal neovascularization

Role of circular RNAs in preeclampsia (Review)

Preeclampsia (PE) is a hypertensive disorder of pregnancy characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, which affects 3-8% of pregnant individuals worldwide each year. Prevention, diagnosis and treatment of PE are some of the most important problems faced by obstetrics. There is growing evidence that circular RNAs (circRNAs) are involved in the pathogenesis of PE. The present review summarizes the research progress of circRNAs and then describes the expression patterns of circRNAs in PE and their functional mechanisms affecting PE development. The role of circRNAs as biomarkers for the diagnosis of PE, and the research status of circRNAs in PE are summarized in the hope of finding novel strategies for the prevention and treatment of PE.

Enhanced Ocular Delivery of Beva via Ultra-Small Polymeric Micelles for Noninvasive Anti-VEGF Therapy

Pathological ocular neovascularization resulting from retinal ischemia constitutes a major cause of vision loss. Current anti-VEGF therapies rely on burdensome intravitreal injections of Bevacizumab (Beva). Herein ultrasmall polymeric micelles encapsulating Beva (P@Beva) are developed for noninvasive topical delivery to posterior eye tissues. Beva is efficiently loaded into 11 nm micelles fabricated via self-assembly of hyperbranched amphiphilic copolymers. The neutral, brush-like micelles demonstrate excellent drug encapsulation and colloidal stability. In vitro, P@Beva enhances intracellular delivery of Beva in ocular cells versus free drug. Ex vivo corneal and conjunctival-sclera-choroidal tissues transport after eye drops are improved 23-fold and 7.9-fold, respectively. Anti-angiogenic bioactivity is retained with P@Beva eliciting greater inhibition of endothelial tube formation and choroid sprouting over Beva alone. Remarkably, in an oxygen-induced retinopathy (OIR) model, topical P@Beva matching efficacy of intravitreal Beva injection, is the clinical standard. Comprehensive biocompatibility verifies safety. Overall, this pioneering protein delivery platform holds promise to shift paradigms from invasive intravitreal injections toward simplified, noninvasive administration of biotherapeutics targeting posterior eye diseases.

Inhibition of miR-578 through SOCS2-dependent manner reverses gefitinib resistance in NSCLC cells

BACKGROUND

Nonsmall-cell lung cancer (NSCLC) has emerged as one of the dreadful lung cancers globally due to its increased mortality rates. Concerning chemotherapy, gefitinib has been employed as an effective first-line treatment drug for NSCLC. Nonetheless, the acquired resistance to gefitinib has remained one of the treatment obstacles of NSCLC, requiring improvement in the therapeutic effect of gefitinib.

METHODS

Initially, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and Western blotting (WB) analyses were conducted to measure micro-ribose nucleic acid (miRNA, specifically miR-578) and suppressor of cytokine signaling 2 (SOCS2) levels in the clinical samples. Further, NSCLC cell lines resistance to gefitinib, established in vitro, were transfected by miR-578 inhibitor, miR-578 mimic, and si-SOCS2. Similarly, the xenograft mouse model in vivo was constructed to validate the reversing effect of miR-578.

RESULTS

Our findings indicated the increased miR-578 expression levels in the gefitinib resistance group. Further, inhibiting the miR-578 expression substantially reversed the gefitinib resistance. In addition, the miR-578 effect was modulated via the SOCS2 expression level. The decreased gefitinib resistance effect of miR-578 was weakened by inhibiting the SOCS2 expression.

CONCLUSION

These findings demonstrated that miR-578 effectively abolished gefitinib resistance by regulating the SOCS2 expression within NSCLC cells in vitro and in vivo. Together, these results will undoubtedly support a reference to provide potential molecular therapeutic targets and clinical treatments for treating NSCLC patients.

Epigenetic Switches in Retinal Homeostasis and Target for Drug Development

Retinal homeostasis, a tightly regulated process maintaining the functional integrity of the retina, is vital for visual function. Emerging research has unveiled the critical role of epigenetic regulation in controlling gene expression patterns during retinal development, maintenance, and response to mutational loads and injuries. Epigenetic switches, including DNA methylation, histone modifications, and non-coding RNAs, play pivotal roles in orchestrating retinal gene expression and cellular responses through various intracellular, extracellular, and environmental modulators. This review compiles the current knowledge on epigenetic switches in retinal homeostasis, providing a deeper understanding of their impact on retinal structural integrity and function and using them as potential targets for therapeutic interventions.

Circ_0020014 mediates CTSB expression and participates in IL-1β-prompted chondrocyte injury via interacting with miR-24-3p

BACKGROUND

Recent studies have shown that circRNAs are involved in the pathogenesis of osteoarthritis (OA) by affecting various fundamental cellular characteristics of chondrocytes. The purpose of this paper is to investigate the role and regulatory mechanism of hsa_circ_0020014 (circ_0020014) in chondrocytes of OA.

METHODS

The inflammatory cytokine interleukin 1 beta (IL-1β) was used to stimulate human chondrocytes. Cell viability, proliferation, and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), 5-Ethynyl-2'-deoxyuridine (EdU), and flow cytometry assays. Several protein levels were determined by western blotting (WB). Levels of inflammatory cytokines and malondialdehyde (MDA) were determined by enzyme-linked immunosorbent assay (ELISA). Relative expression of circ_0020014 was estimated by real-time polymerase quantitative chain reaction (RT-qPCR). Bioinformatics prediction combined with dual-luciferase reporter, RIP and RNA pull-down assays were done to probe into the regulatory mechanism of circ_0020014.

RESULTS

Circ_0020014 was overexpressed in OA patient-derived articular cartilages and IL-1β-stimulated chondrocytes. Silencing of circ_0020014 lighted IL-1β-prompted chondrocyte proliferation repression, apoptosis, inflammation, and oxidative stress. Mechanically, circ_0020014 functioned as a miR-24-3p molecular sponge to regulate cathepsin B (CTSB) expression. Furthermore, miR-24-3p inhibition alleviated circ_0020014 knockdown-mediation repression of IL-1β-urged chondrocyte injury. In addition, CTSB overexpression whittled miR-24-3p upregulation-mediated suppression of IL-1β-urged chondrocyte injury.

CONCLUSION

Our findings demonstrated that the circ_0020014/miR-24-3p/CTSB axis was associated with IL-1β-prompted chondrocyte injury, supporting the involvement of circ_0020014 in the OA pathogenesis.

5α-Hydroxycostic acid inhibits choroidal neovascularization in rats through a dual signalling pathway mediated by VEGF and angiopoietin 2

BACKGROUND

5α-Hydroxycostic acid is a eudemane sesquiterpene that is isolated from the natural plant, Laggera alata. It exerts anti-inflammatory and anti-angiogenic effects on human breast cancer cells, but its role and underlying mechanism in choroidal neovascularization (CNV) are still unclear. We conducted a study to verify that 5α-Hydroxycostic acid can inhibit the formation and leakage of CNV, and describe the possible dual pathway by which it exerts its inhibitory effects in this process.

METHODS

An in vitro model of choroidal neovascularization was established using VEGF164, while a rat model of choroidal neovascularization was established using a 532 nm laser. In both models, the effects of 5α-Hydroxycostic acid in vivo and in vitro were evaluated to determine its inhibitory effect on abnormal cell proliferation, migration and tubule formation, as well as its effect on pathological changes in choroidal tissues and the area of neovascularization leakage in rats. The levels of components in the VEGF/VEGFR and Ang2/Tie2 signaling pathways were measured in tissues and cells.

RESULTS

In vitro experiments have shown that 5α-Hydroxycostic acid can inhibit abnormal cell proliferation, migration and angiogenesis. Additionally, 5α-Hydroxycostic acid enhances cell adhesion by inhibiting the phosphorylation pathways of VEGFR2 and Tie2. In vivo experiments demonstrated that 5α-Hydroxycostic acid has a positive therapeutic effect on choroidal neovascularization in rats. It can effectively reduce vascular leakage, consistent with the results of the cell experiments.

CONCLUSION

5α-Hydroxycostic acid can inhibit choroidal neovascularization by interfering with the VEGF- and Ang2/Tie2-related pathways, and it may be a good candidate drug for treating CNV.

Pathogenesis of myopic choroidal neovascularization: A systematic review and meta-analysis

Myopic choroidal neovascularization (CNV) is a vision-threatening complication of high myopia. Here, we systematically review cohort, case-control, and cross-sectional studies in PubMed, Embase, and Web of Science, and summarize the associated factors of myopic CNV using meta-analysis where applicable. Among 1,333 records assessed, 50 were found eligible, all having a low-to-moderate risk of bias. Highly myopic eyes with CNV had a higher risk of lacquer cracks (odds ratio = 2.88) and patchy chorioretinal atrophy (odds ratio = 3.43) than those without. The mean posterior staphyloma height (µm) was greater in myopic CNV eyes than in highly myopic eyes without CNV (mean difference = 82.03). The thinning of choroidal thickness (µm) between myopic eyes with and without CNV differed significantly (mean difference = -47.76). The level of vascular endothelial growth factor (pg/ml) in the aqueous humor of myopic CNV eyes was significantly higher than in highly myopic eyes without CNV (mean difference = 24.98), the same as interleukin-8 (IL-8) (pg/ml, mean difference = 7.73). Single-nucleotide polymorphisms in the vascular endothelial growth factor, complement factor I, and collagen type VIII alpha 1 genes were associated with myopic CNV. We found that myopic CNV eyes have a higher ratio of lacquer cracks and patchy chorioretinal atrophy, thinner choroid, greater posterior staphyloma height, and a higher level of vascular endothelial growth factor and IL-8 in aqueous. Structural predisposing lesions, hemodynamic, genetic, and systemic factors are also associated with myopic CNV.

CircRNA in ocular neovascular diseases: Fundamental mechanism and clinical potential

Ocular neovascular disease (OND), characterized by the aberrant formation of immature blood vessels, is the leading cause of vision impairment and blindness. It is important to find effective ways to diagnose and treat these diseases. Circular RNA (circRNA) is a group of endogenous non-coding RNA that play a crucial role in regulating different biological processes. Due to their close association with ocular disease and angiogenesis, circRNAs have become a hotspot in OND research. In this review, we intensively investigate the possibility of using circRNAs in the management of ONDs. In general, angiogenesis is divided into five phases. On the basis of these five steps, we describe the potential of using circRNAs by introducing how they regulate angiogenesis. Subsequently, the interactions between circRNAs and ONDs, including pterygium, corneal neovascularization, age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity, are analyzed in detail. We also introduce the potential use of circRNAs as OND diagnostic biomarkers. Finally, we summarize the prospects of using circRNAs as a potential strategy in OND management. The gaps in recent research are also pointed out with the purpose of promoting the introduction of circRNAs into clinical applications.

Identification and characterization of differentially expressed circular RNAs in extraocular muscle of oculomotor nerve palsy

BACKGROUND

Oculomotor nerve palsy (ONP) is a neuroparalytic disorder resulting in dysfunction of innervating extraocular muscles (EOMs), of which the pathological characteristics remain underexplored.

METHODS

In this study, medial rectus muscle tissue samples from four ONP patients and four constant exotropia (CXT) patients were collected for RNA sequencing. Differentially expressed circular RNAs (circRNAs) were identified and included in functional enrichment analysis, followed by interaction analysis with microRNAs and mRNAs as well as RNA binding proteins. Furthermore, RT-qPCR was used to validate the expression level of the differentially expressed circRNAs.

RESULTS

A total of 84 differentially expressed circRNAs were identified from 10,504 predicted circRNAs. Functional enrichment analysis indicated that the differentially expressed circRNAs significantly correlated with skeletal muscle contraction. In addition, interaction analyses showed that up-regulated circRNA_03628 was significantly interacted with RNA binding protein AGO2 and EIF4A3 as well as microRNA hsa-miR-188-5p and hsa-miR-4529-5p. The up-regulation of circRNA_03628 was validated by RT-qPCR, followed by further elaboration of the expression, location and clinical significance of circRNA_03628 in EOMs of ONP.

CONCLUSIONS

Our study may shed light on the role of differentially expressed circRNAs, especially circRNA_03628, in the pathological changes of EOMs in ONP.

Mechanism of circular RNA-mediated regulation of L-DOPA to improve wet age-related macular degeneration

This study aimed to investigate the effect and mechanism of levodopa (L-DOPA) in the treatment of age-related macular degeneration (AMD). A wet AMD cell model was created via CoCl₂ treatment of ARPE-19 cells. The cytoprotective effects of L-DOPA in the model were determined using CCK-8, flow cytometry, TUNEL, qPCR, and ELISA assays. Subsequently, circRNA sequencing and bioinformatics analysis were used to screen differentially expressed circRNAs, which were overexpressed in ARPE-19 cells, to explore their role in wet AMD. The findings revealed that 200 μM CoCl₂ treatment inhibited the cell viability and the production of tyrosinase, melanin, and pigment epithelium-derived growth factor but promoted apoptosis and the expression of vascular endothelial growth factor in ARPE-19 cells. Moreover, 20 μM L-DOPA exerted the best therapeutic effect on the model. qPCR showed that Hsa_circ_0018401 (circ-SGMS1) was significantly differentially expressed in each experimental group, which was consistent with the sequencing results. The overexpression of circ-SGMS1 in ARPE-19 cells reversed the effects of CoCl₂. Fluorescence in situ hybridization showed that circ-SGMS1 was expressed more in the nucleus than in the cytoplasm. qPCR assays indicated that circ-SGMS1 overexpression did not have a significant effect on the expressions of VEGFA and KDR but significantly reduced the expressions of HIF-1a and THBS1. Circ-SGMS1 is of immense significance in the AMD treatment mechanism of L-DOPA. Overexpression of circ-SGMS1 may alleviate wet AMD by inhibiting HIF-1a and THBS1 expression.

Investigating Circular RNAs Using qRT-PCR; Roundup of Optimization and Processing Steps

Circular RNAs (circRNAs) have gained recent attraction due to their functional versatility and particular structure connected to human diseases. Current investigations are focused on the interplay between their ability to sponge smaller species of RNAs, such as microRNAs (miRNAs), thus influencing their regulatory activity on gene expression and protein templates. Therefore, their reported implication in various biological processes axis has resulted in an accumulating number of studies. While the testing and annotation methods of novel circular transcripts are still under development, there is still a plethora of transcript candidates suitable for investigation in human disease. The discordance in the literature regarding the approaches used in circRNAs quantification and validation methods, especially regarding qRT-PCR, the current golden standard procedure, leads to high result variability and undermines the replicability of the studies. Therefore, our study will offer several valuable insights into bioinformatic data for experimental design for circRNA investigation and in vitro aspects. Specifically, we will highlight key aspects such as circRNA database annotation divergent primer design and several processing steps, such as RNAse R treatment optimization and circRNA enrichment assessment. Additionally, we will provide insights into the exploration of circRNA-miRNA interactions, a prerequisite for further functional investigations. With this, we aim to contribute to the methodological consensus in a currently expanding field with possible implications for assessing therapeutic targets and biomarker discovery.

The impact of non-coding RNAs in the pathobiology of eye disorders

Eye disorders are common disorders with significant effects on personal, economic, and social aspects of life. These disorders have a genetic background and are associated with dysregulation of non-coding RNAs. Three classes of these transcripts, namely long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs) have established roles in the regulation of gene expression and pathoetiology of ocular disorders. H19, MEG3, BANCR, UCA1, HOTAIR, ANRIL, XIST and MIAT are among important lncRNAs in ocular disorders. CircRNAs from ZBTB44, HIPK3, circ-PSEN1, COL1A2, ZNF532 and FAM158A loci have also been found to affect pathoetiology of ocular disorders. Both lncRNAs and circRNAs can serve as molecular sponges for miRNAs. In this review, we searched PubMed and Google Scholar databases to find the research articles summarizing the impact of non-coding RNAs in ocular disorders. The results of these studies would help in identification of suitable targets for treatment of ocular disorders.

Circular RNA in Retina: A Potential Biomarker and Therapeutic Target

Circular RNA (circRNA) is a newly discovered noncoding RNA, which forms a closed ring with more than 200 bases in length. CircRNA is formed by back splicing of precursor RNA, and its expression abundance in body fluid is up to 10 times that of homologous linear transcripts. Recently, novel activities for circRNA in various diseases have emerged, ranging from cancer therapy and neurodegenerative diseases. Here, we reviewed the literature on the biogenesis of circRNA and its relationship with retinal diseases in recent years. We first described the mechanism, existing form and main function of circRNA. Next, we also pinpoint that circRNA has great value in the diagnosis and treatment of retinal diseases represented by retinoblastoma, retinal degeneration, and diabetic retinopathy. By this review, we hope to explore more possibilities of circRNA in clinical diagnosis and treatment.

The Differential Expression of Circular RNAs and the Role of circAFF1 in Lens Epithelial Cells of High-Myopic Cataract

High-myopic cataract (HMC) is a complex cataract with earlier onset and more rapid progress than age-related cataract (ARC). Circular RNAs (circRNAs) have been implicated in many diseases. However, their involvement in HMC remain largely unexplored. To investigate the role of dysregulated circRNAs in HMC, lens epithelium samples from 24 HMC and 24 ARC patients were used for whole transcriptome sequencing. Compared with ARC, HMC had 3687 uniquely expressed circRNAs and 1163 significantly differentially expressed circRNAs (DEcRs) (|log₂FC| > 1, p < 0.05). A putative circRNA-miRNA-mRNA network was constructed based on correlation analysis. We validated the differential expression of 3 DEcRs by quantitative polymerase chain reaction (qPCR) using different sets of samples. We further investigated the role of circAFF1 in cultured lens epithelial cells (LECs) and found that the overexpression of circAFF1 promoted cell proliferation, migration and inhibited apoptosis. We also showed that circAFF1 upregulated Tropomyosin 1 (TPM1) expression by sponging miR-760, which was consistent with the network prediction. Collectively, our study suggested the involvement of circRNAs in the pathogenesis of HMC and provide a resource for further study on this topic.

Circ_0007534 as new emerging target in cancer: Biological functions and molecular interactions

Circular RNA (circRNAs), an important member of the non-coding RNA (ncRNA) family, are widely expressed in a variety of biological cells. Owing to their stable structures, sequence conservations, and cell- or tissue-specific expressions, these RNA have become a popular subject of scientific research. With the development of sequencing methods, it has been revealed that circRNAs exert their biological function by sponging microRNAs (miRNAs), regulating transcription, or binding to proteins. Humans have historically been significantly impacted by various types of cancer. Studies have shown that circRNAs are abnormally expressed in various cancers and are involved in the occurrence and development of malignant tumors, such as tumor cell proliferation, migration, and invasion. As one of its star molecules, circ_0007534 is upregulated in colorectal, cervical, and pancreatic cancers; is closely related to the occurrence, development, and prognosis of tumors; and is expected to become a novel tumor marker and therapeutic target. This article briefly reviews the expression and mechanism of circ_0007534 in malignant tumors based on the domestic and foreign literature.

Potential epigenetic molecular regulatory networks in ocular neovascularization

Neovascularization is one of the many manifestations of ocular diseases, including corneal injury and vascular diseases of the retina and choroid. Although anti-VEGF drugs have been used to effectively treat neovascularization, long-term use of anti-angiogenic factors can cause a variety of neurological and developmental side effects. As a result, better drugs to treat ocular neovascularization are urgently required. There is mounting evidence that epigenetic regulation is important in ocular neovascularization. DNA methylation and histone modification, non-coding RNA, and mRNA modification are all examples of epigenetic mechanisms. In order to shed new light on epigenetic therapeutics in ocular neovascularization, this review focuses on recent advances in the epigenetic control of ocular neovascularization as well as discusses these new mechanisms.

CircRNAs in lung cancer- role and clinical application

Lung cancer holds the highest mortality rate among malignancies worldwide. Nevertheless, the potential molecular mechanisms of its tumorigenesis and evolution remain obscure. Circular RNAs (circRNAs), a broad category of covalently closed molecules, follow a malignancy-restricted expression pattern. Leading-edge studies have demonstrated the clinical application prospects of circRNAs in lung cancer. Herein, this review elucidates the biogenesis, biological functions, and pathophysiology of circRNAs. Furthermore, we underscore the forefront of the diagnostic, prognostic, and therapeutic potential of circRNAs in lung cancer as well as discuss the bottleneck that needs to be overcome to translate the basic advances of circRNAs into clinical practice.

CircRNA-miRNA interactions in atherogenesis

Atherosclerosis is the major cause of coronary artery disease (CAD) which includes unstable angina, myocardial infarction, and heart failure. The onset of atherogenesis, a process of atherosclerotic lesion formation in the intima of arteries, is driven by lipid accumulation, a vicious cycle of reactive oxygen species (ROS)-induced oxidative stress and inflammatory reactions leading to endothelial cell (EC) dysfunction, vascular smooth muscle cell (VSMC) activation, and foam cell formation which further fuel plaque formation and destabilization. In recent years, there is a surge in the number of publications reporting the involvement of circular RNAs (circRNAs) in the pathogenesis of cardiovascular diseases, cancers, and metabolic syndromes. These studies have advanced our understanding on the biological functions of circRNAs. One of the most common mechanism of action of circRNAs reported is the sponging of microRNAs (miRNAs) by binding to the miRNAs response element (MRE), thereby indirectly increases the transcription of their target messenger RNAs (mRNAs). Individual networks of circRNA-miRNA-mRNA associated with atherogenesis have been extensively reported, however, there is a need to connect these findings for a complete overview. This review aims to provide an update on atherogenesis-related circRNAs and analyze the circRNA-miRNA-mRNA interactions in atherogenesis. The atherogenic mechanisms and clinical relevance of each atherogenesis-related circRNA were systematically discussed for better understanding of the knowledge gap in this area.

Hypoxia-Induced circRNAs in Human Diseases: From Mechanisms to Potential Applications

Circular RNAs (circRNAs) are a special class of endogenous RNAs characterized by closed loop structures lacking 5′ to 3′ polarity and polyadenylated tails. They are widely present in various organisms and are more stable and conserved than linear RNAs. Accumulating evidence indicates that circRNAs play important roles in physiology-related processes. Under pathological conditions, hypoxia usually worsens disease progression by manipulating the microenvironment for inflammation and invasion through various dysregulated biological molecules. Among them, circRNAs, which are involved in many human diseases, including cancer, are associated with the overexpression of hypoxia-inducible factors. However, the precise mechanisms of hypoxic regulation by circRNAs remain largely unknown. This review summarizes emerging evidence regarding the interplay between circRNAs and hypoxia in the pathophysiological changes of diverse human diseases, including cancer. Next, the impact of hypoxia-induced circRNAs on cancer progression, therapeutic resistance, angiogenesis, and energy metabolism will be discussed. Last, but not least, the potential application of circRNAs in the early detection, prognosis, and treatment of various diseases will be highlighted.

The role of circRNAs in the regulation of myocardial angiogenesis in coronary heart disease

During myocardial ischemia, timely reperfusion is critical to limit infarct area and the overall loss of cardiac contractile function. New treatment strategies need to be developed for patients who are neither able to receive interventional treatment nor suitable for surgical blood transport reconstruction surgery. Therapeutic angiogenesis is a promising approach that can be used to guide new treatment strategies. The goal of these therapies is to form new blood vessels or promote the maturation of existing vasculature systems, bypassing blocked arteries to maintain organ perfusion, thereby relieving symptoms and preventing the remodeling of bad organs. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), have been attracted much attention for their roles in various physiological and pathological processes. There is growing evidence that ncRNAs, especially circRNAs, play an important role in the regulation of cardiomyopathy angiogenesis due to its diversity of functions. Therefore, this article reviews the role and mechanisms of circRNA in myocardial angiogenesis to better understand the role of circRNAs in myocardial angiogenesis, which may provide useful insights and new revelations for the research field of identifying diagnostic markers and therapeutic approaches for the treatment of coronary artery disease.

Exosomal circRELL1 serves as a miR-637 sponge to modulate gastric cancer progression via regulating autophagy activation

Circular RNAs (circRNAs) play a vital role in the occurrence and development of tumors, including gastric cancer (GC). However, there are still many circRNAs related to GC whose functions and molecular mechanisms remain undetermined. Herein, we discover circRNA RELL1, which has not been investigated in GC, and it is markedly downregulated in GC tissues, which is related with poor prognosis, more pronounced lymph node metastasis and poor TNM stage. After confirming the circular structure of circRELL1, we found that circRELL1 could block cell proliferation, invasion, migration, and anti-apoptosis in patients with GC by a series of in vivo and in vitro function-related studies. Further mechanism investigation demonstrated that circRELL1 could sponge miR-637 and indirectly unregulated the expression of EPHB3 via modulating autophagy activation in GC. Additionally, circRELL1 can be transmitted by exosomal communication, and exosomal circRELL1 suppressed the malignant behavior of GC in vivo and in vitro. Taken together, this study elucidates the suppressive roles of circRELL1/miR-637/EPHB3 axis through autophagy activation in GC progression, inspiring for further understanding of the underlying molecular mechanisms of GC and providing a promising novel diagnostic circulating biomarker and therapeutic target in GC.

Circle the Cardiac Remodeling With circRNAs

Cardiac remodeling occurs after the heart is exposed to stress, which is manifested by pathological processes such as cardiomyocyte hypertrophy and apoptosis, dendritic cells activation and cytokine secretion, proliferation and activation of fibroblasts, and finally leads to heart failure. Circular RNAs (circRNAs) are recently recognized as a specific type of non-coding RNAs that are expressed in different species, in different stages of development, and in different pathological conditions. Growing evidences have implicated that circRNAs play important regulatory roles in the pathogenesis of a variety of cardiovascular diseases. In this review, we summarize the biological origin, characteristics, functional classification of circRNAs and their regulatory functions in cardiomyocytes, endothelial cells, fibroblasts, immune cells, and exosomes in the pathogenesis of cardiac remodeling.

Genetic Variants and Functional Analyses of the ATG16L1 Gene Promoter in Acute Myocardial Infarction

Background

Acute myocardial infarction (AMI), a common complex disease caused by an interaction between genetic and environmental factors, is a serious type of coronary artery disease and is also a leading cause of death worldwide. Autophagy-related 16-like 1 (ATG16L1) is a key regulatory factor of autophagy and plays an important role in induced autophagy. In the cardiovascular system, autophagy is essential to preserve the homeostasis and function of the heart and blood vessels. No studies have hitherto examined the association between AMI and ATG16L1 gene promoter.

Methods

We conducted a case-control study, using polymerase chain reaction and sequencing techniques, dual luciferase reporter assay, and electrophoretic mobility shift assay, to analyze genetic and functional variation in the ATG16L1 gene promoter between AMI and controls. A variety of statistical analyses were used to analyze the allele and genotype frequencies and the relationship between single-nucleotide polymorphisms (SNPs) and AMI.

Results

In all, 10 SNPs and two DNA-sequence variants (DSVs) were identified in 688 subjects, and three ATG16L1 gene promoter mutations [g.233250693 T > C (rs185213911), g.233250946 G > A (rs568956599), g.233251133 C > G (rs1301744254)] that were identified in AMI patients significantly altered the transcriptional activity of ATG16L1 gene promoter in HEH2, HEK-293, and H9c2 cells (P < 0.05). Further electrophoretic mobility shift assays indicated that the SNPs affected the binding of transcription factors (P < 0.01).

Conclusion

ATG16L1 gene promoter mutations in AMI patients may affect the binding of transcription factors and change the transcriptional activity of the ATG16L1 gene, changing the level of autophagy and contributing to the occurrence and development of AMI as rare and low-frequency risk factors.

Circular RNAs: Expression, localization, and therapeutic potentials

Circular RNAs (circRNAs) are RNAs with a unique circular structure that is generated from back-splicing processes. These circular molecules were discovered more than 40 years ago but failed to raise scientific interest until lately. Increasing studies have found that these circular RNAs might not just be byproducts of the splicing process but possess important regulatory functions through different cellular events. Most circular RNAs are currently being studied in the field of cancer, and many of them have been confirmed to be involved in the process of tumorigenesis. However, many circular RNAs are implicated in the developmental stages of diseases other than cancer. In this review, we focus on discussing the role of circular RNAs in non-cancer diseases, especially in cardiovascular diseases. Following the summary of the life cycle of circRNAs, we provide input on studying circRNA-protein interactions based on our experience, which modulate protein translocation. Furthermore, we outline the potential of circRNAs to be potent biomarkers, effective therapeutic targets, and potential treatments in cardiovascular diseases as well as other non-cancer fields.

Downregulation of circular RNA circDOCK7 identified from diabetic rats after sleeve gastrectomy contributes to hepatocyte apoptosis through regulating miR-139-3p and MCM3

Sleeve gastrectomy (SG) is the most widely used bariatric procedures globally, which could improve glucose and lipid metabolism dramatically. Circular RNAs (circRNAs) are being increasingly implicated in numerous pathophysiological processes. However, for diabetes mellitus (DM), the expression and function of circRNAs remain largely undetermined, in particular, whether circRNAs mediate the amelioration of DM observed after SG. Using a diabetic rat model, we subjected liver tissue from SG and sham-operated rats to RNA sequencing. Amongst the 103 differentially regulated circRNAs identified in diabetic rats after SG, we focused on circDOCK7, a highly expressed circRNA derived from the back-splicing of the DOCK7 gene. Silencing of circDOCK7 significantly inhibited cellular proliferation and induction of apoptosis in insulin-resistant rat hepatocytes. Further analysis indicated circDOCK7 harbored binding sites for miR-139-3p and regulated the expression of minichromosome maintenance 3 (MCM3) through sequestration of miR-139-3p. Our findings therefore demonstrate a novel regulatory pathway involving circDOCK7 that regulates cellular proliferation and apoptosis through increasing the expression of MCM3. Overall, our study establishes a list of specific circRNAs expressed in diabetic rat liver after SG including circDOCK7 which serve as potential biomarkers and treatment targets for DM patients.

Targeting non-coding RNAs for the treatment of retinal diseases

Maintaining visual function is key to establishing improved longevity. However, the numbers of patients with diseases of the retina, the most important tissue for vision and the key to age-related blindness, are not declining due to the increase in the number of aging subjects worldwide and the technological advances in the delivery of premature infants. The primary treatment option for retinal diseases is still surgical intervention and includes laser or photocoagulation, which are associated with various complications and side effects. Many aspects of the pathogenesis of these retinal diseases are still unknown, thereby impeding drug discovery. This has led to an increase in the number of studies focused on the underlying pathogenic mechanisms of retinal diseases. Growing evidence suggests that non-coding RNAs play critical roles in the pathogenesis of retinal diseases. Herein, we have summarized the known functional roles of non-coding RNAs, emphasizing their contribution to the underlying pathogenesis of retinal diseases. In addition, we discuss the modulation of non-coding RNAs as potential therapeutics and the methods to control the non-coding RNAs for the treatment. We expect that targeting non-coding RNAs could be crucial for developing novel therapeutics for progressive diseases including diseases of the retina.

CircRNA Is a Rising Star in Researches of Ocular Diseases

A newly rediscovered subclass of noncoding RNAs, circular RNAs (circRNAs), is produced by a back-splicing mechanism with a covalently closed loop structure. They not only serve as the sponge for microRNAs (miRNAs) and proteins but also regulate gene expression and epigenetic modification, translate into peptides, and generate pseudogenes. Dysregulation of circRNA expression has opened a new chapter in the etiology of various human disorders, including cancer and cardiovascular, neurodegenerative, and ocular diseases. Recent studies recognized the vital roles that circRNAs played in the pathogenesis of various eye diseases, highlighting circRNAs as promising biomarkers for diagnosis and assessment of progression and prognosis. Interventions targeting circRNAs provide insights for developing novel treatments for these ocular diseases. This review summarizes our current perception of the properties, biogenesis, and functions of circRNAs and the development of circRNA researches related to ophthalmologic diseases, including diabetic retinopathy, age-related macular degeneration, retinopathy of prematurity, glaucoma, corneal neovascularization, cataract, pterygium, proliferative vitreoretinopathy, retinoblastoma, and ocular melanoma.

Upregulated hsa_circ_0005785 Facilitates Cell Growth and Metastasis of Hepatocellular Carcinoma Through the miR-578/APRIL Axis

Although accumulating documents have expounded the pivotal position of circular RNAs (circRNAs) in hepatocarcinogenesis and progression, the overwhelming majority of their functions and molecular mechanisms in hepatocellular carcinoma (HCC) are elusive. Herein, we explored the functions and potential mechanisms of hsa_circ_0005785 in HCC, which was aberrantly overexpressed in HCC and related to HCC patients' TNM stage and overall survival. Moreover, hsa_circ_0005785 depletion could repress proliferation and metastasis of the HCC cell in vitro, lead to cell apoptosis and cell-cycle arrest, and restrain HCC cell growth in vivo. Furthermore, mechanism analyses discovered that hsa_circ_0005785 adsorbed miR-578 by playing a miRNA sponge role, which resulted in the derepression of a proliferation-inducing ligand (APRIL) expression, miR-578's mRNA target. Besides, hsa_circ_0005785 reversed the suppressive influence of miR-578 on HCC and accelerated tumor malignant progression through the miR-578/APRIL axis. Taken together, our current study revealed an oncogenic role of hsa_circ_0005785 in the tumorigenesis of HCC. Moreover, targeting to the hsa_circ_0005785/miR-578/APRIL regulatory pathway might be a promising diagnostic and therapeutic strategy for HCC clinical practice.