The influence of circular RNAs on autophagy and disease progression

Curcumin alleviates renal fibrosis in chronic kidney disease by targeting the circ_0008925-related pathway

BACKGROUND

Curcumin has been shown to inhibit renal fibrosis, but whether curcumin mediates renal fibrosis progression by regulating the circular RNA (circRNA)-related pathway remain unclear.

METHODS

TGF-β1 was used to construct renal injury and fibrosis cell model. Cell growth was evaluated by cell counting kit 8 assay, EdU assay and flow cytometry. Fibrosis marker and interleukin 6 signal transducer (IL6ST) protein levels were measured using western bolt analysis. Inflammation factor concentrations were determined by ELISA. Circ_0008925, miR-204-5p and IL6ST expression was assessed by qRT-PCR. Unilateral ureteral obstruction (UUO) mice models were constructed to assess the role of curcumin in vivo.

RESULTS

Curcumin treatment alleviated TGF-β1-induced HK-2 cell apoptosis, inflammation and fibrosis in vitro, as well as relieved renal injury in UUO mice models in vivo. Circ_0008925 was highly expressed in TGF-β1-induced HK-2 cells and its expression was inhibited by curcumin. Circ_0008925 could sponge miR-204-5p to positively regulate IL6ST. The inhibition effect of curcumin on TGF-β1-induced HK-2 cell injury and fibrosis was reversed by circ_0008925 overexpression, miR-204-5p inhibitor or IL6ST upregulation. Besides, circ_0008925 knockdown inhibited TGF-β1-induced HK-2 cell injury and fibrosis by suppressing IL6ST expression.

CONCLUSION

Curcumin relieved renal fibrosis through regulating circ_0008925/miR-204-5p/IL6ST axis.

MSC-Derived Extracellular Vesicles: Roles and Molecular Mechanisms for Tissue Repair

Mesenchymal stem cells (MSCs) are pluripotent stem cells that have great potential in the field of regenerative medicine. Extracellular vesicles that derived from MSCs inherit the bioactive molecules, including lipids, proteins, nucleic acids, from the donate cells. With similar biological functions as MSCs, MSC-EVs show lower toxicity, better biocompatibility, stability, and less immune rejection. Therefore, MSC-EVs are emerging as a cell-free alternative therapy for MSC-based cell therapy. Here, we reviewed the characteristics of different subtype of MSC-EVs, the functional molecules in MSC-EVs for tissue repair, the potential applications of MSC-EVs for different tissue injuries in recent three years, and the clinical progress as well as the existing challenges in MSC-EV based therapy. This review would provide some insights for the future researches and clinical translation of MSC-EVs in regenerative medicine.

Circ_0098181 binds PKM2 to attenuate liver fibrosis

Background

Liver cirrhosis seriously harms human health and fibrosis is the essential pathological process of cirrhosis. Recently, circular RNAs (circRNAs) were found to play critical roles in liver fibrosis, but the key circRNAs and precise mechanisms remained unclear. This study aimed to investigate the effect of circ_0098181 in fibrogenesis and explore its mechanism.

Methods

RNA sequencing was conducted to identify circRNA signatures in human liver cirrhotic tissues. Hepatic stellate cells (HSCs) (including primary rat HSCs, LX2, HSC-T6) and carbon tetrachloride (CCl4) induced liver cirrhosis model were used to explore the role of circ_0098181 on HSC activation and liver fibrogenesis in vitro and in vivo. RNA sequencing, RNA pull-down, mass spectrometry, and RNA immunoprecipitation (RIP) experiments were performed to elucidate the mechanism.

Results

Circ_0098181 was obviously reduced in human fibrotic liver tissues and activated HSCs. Exogenous administration of circ_0098181 blocked the activation, proliferation, and migration of HSCs in vitro and mitigated the progression of CCl4-induced liver fibrosis in vivo. Mechanistically, adenosine deaminase acting on RNA1 (ADAR1) combined with the intronic complementary sequences (ICSs) in the flanking regions, thereby regulating the biogenesis of circ_0098181. RNA sequencing and qRT-PCR revealed the suppression of circ_0098181 on pro-inflammation cytokines expression (TNFα, Fas, Cxcl11, etc.). RNA pull-down, mass spectrometry, and RIP experiments indicated that pyruvate kinase M2 (PKM2) was the direct target of circ_0098181. Circ_0098181 bound to PKM2, restrained its nuclear translocation and phosphorylation.

Conclusion

In conclusion, circ_0098181 exerts a significant anti-fibrotic effect by binding PKM2 to repress its nuclear translocation and inhibiting hepatic inflammation, suggesting the promising therapeutic merit in liver cirrhosis.

o8G-modified circPLCE1 inhibits lung cancer progression via chaperone-mediated autophagy

BACKGROUND

Lung cancer poses a serious threat to human health, but its molecular mechanisms remain unclear. Circular RNAs (circRNAs) are closely associated with tumour progression, and the important role of 8-oxoguanine (o8G) modification in regulating the fate of RNA has been gradually revealed. However, o8G modification of circRNAs has not been reported. We identified circPLCE1, which is significantly downregulated in lung cancer, and further investigated the o8G modification of circPLCE1 and the related mechanism in lung cancer progression.

METHODS

We identified differentially expressed circRNAs by RNA high-throughput sequencing and then conducted methylated RNA immunoprecipitation (MeRIP), immunofluorescence (IF) analysis, crosslinking immunoprecipitation (CLIP) and actinomycin D (ActD) assays to explore circPLCE1 o8G modification. The biological functions of circPLCE1 in vivo and in vitro were clarified via establishing a circPLCE1 silencing/overexpression system. Tagged RNA affinity purification (TRAP), RNA Immunoprecipitation (RIP) and coimmunoprecipitation (Co-IP) assays, and pSIN-PAmCherry-KFERQ-NE reporter gene were used to elucidate the molecular mechanism by which circPLCE1 inhibits lung cancer progression.

RESULTS

This study revealed that reactive oxygen species (ROS) can induce circPLCE1 o8G modification and that AUF1 can mediate a decrease in circPLCE1 stability. We found that circPLCE1 significantly inhibited lung cancer progression in vitro and in vivo and that its expression was associated with tumour stage and prognosis. The molecular mechanism was elucidated: circPLCE1 targets the HSC70 protein, increases its ubiquitination level, regulates ATG5-dependent macroautophagy via the chaperone-mediated autophagy (CMA) pathway, and ultimately inhibits lung cancer progression.

CONCLUSION

o8G-modified circPLCE1 inhibits lung cancer progression through CMA to inhibit macroautophagy and alter cell fate. This study provides not only a new theoretical basis for elucidating the molecular mechanism of lung cancer progression but also potential targets for lung cancer treatment.

Unlocking the potential of organopalladium complexes for high-grade serous ovarian cancer therapy

High-Grade Serous Ovarian Cancer (HGSOC) is the most common and lethal subtype of ovarian cancer, known for its high aggressiveness and extensive genomic alterations. Typically diagnosed at an advanced stage, HGSOC presents formidable challenges in drug therapy. The limited efficacy of standard treatments, development of chemoresistance, scarcity of targeted therapies, and significant tumor heterogeneity render this disease incurable with current treatment options, highlighting the urgent need for novel therapeutic approaches to improve patient outcomes. In this study we report a straightforward and stereoselective synthetic route to novel Pd(II)-vinyl and -butadienyl complexes bearing a wide range of monodentate and bidentate ligands. Most of the synthesized complexes exhibited good to excellent in vitro anticancer activity against ovarian cancer cells. Particularly promising is the water-soluble complex bearing two PTA (1,3,5-triaza-7-phosphaadamantane) ligands and the Pd(II)-butadienyl fragment. This compound combines excellent cytotoxicity towards cancer cells with substantial inactivity towards non-cancerous ones. This derivative was selected for further studies on ex vivo tumor organoids and in vivo mouse models, which demonstrate its remarkable efficacy with surprisingly low collateral toxicity even at high dosages. Moreover, this class of compounds appears to operate through a ferroptotic mechanism, thus representing the first such example for an organopalladium compound.

Circular RNA circCLASP2 promotes nasopharyngeal carcinoma progression through binding to DHX9 to enhance PCMT1 translation

BACKGROUND

Circular RNAs (circRNAs), characterized by their covalently closed-loop structures, constitute a distinct class of non-coding RNAs. They play pivotal regulatory roles within cells and are intricately associated with the progression of malignant tumors. However, their roles and the underlying mechanisms in nasopharyngeal carcinoma (NPC) progression have yet to be fully uncovered and comprehensively understood.

METHODS

Employing RNA sequencing technology, high-abundance circular RNAs in NPC were identified. Expression analysis of circCLASP2 in NPC tissues was conducted using quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization experiments. Through in vitro and in vivo functional assays, the influence of circCLASP2 on the proliferation and metastasis of NPC was investigated. LC-MS/MS technology analyzed the binding partners of circCLASP2, its differentially regulated targets, and the associated proteins of PCMT1. Interactions among circCLASP2, DHX9 protein, and PCMT1 mRNA were elucidated through RNA immunoprecipitation and RNA pull-down techniques. The effects of circCLASP2 and DHX9 on RNA G-quadruplex (rG4) structures and PCMT1 mRNA translation were explored through immunofluorescence (IF), ribosomal gradient separation, and dual-luciferase reporter assays. Immunoprecipitation (IP) revealed the downstream effector of the circCLASP2-DHX9-PCMT1 regulatory axis and Phalloidin staining confirmed its ultimate effect on the cytoskeleton. PDS treatment was applied for interventions in NPC, demonstrating potential therapeutic avenues.

RESULTS

Our research revealed that circCLASP2, a novel circRNA that has not been reported in tumors, is upregulated in NPC and fosters cell proliferation and metastasis both in vitro and in vivo. Mechanistically, circCLASP2 acts as a molecular scaffold, facilitating the approximation of DHX9 to PCMT1 mRNA. DHX9 unwinds the inhibitory rG4 structure near the translation initiation site on PCMT1 mRNA, increasing PCMT1 expression. PCMT1 binds to and upregulates cytoskeleton-associated proteins, modulating cytoskeleton strength and dynamics and ultimately driving NPC cell proliferation and metastasis. In both in vitro and in vivo experiments, PDS significantly inhibits NPC growth and metastasis, showcasing promising therapeutic potential.

CONCLUSIONS

Our investigation pinpointed a circular RNA, circCLASP2, which is upregulated in NPC and augments cytoskeletal functions via the DHX9-PCMT1 axis, contributing to the malignancy progression of NPC. This pathway holds promise as a potential therapeutic target for NPC. Furthermore, these molecules could also serve as biomarkers for adjunct diagnosis and prognosis assessment in NPC.

Analysis of the Clinical Value of hsa_circ_0001955 in Papillary Thyroid Cancer Treated with 131 Iodine

The prevalent histological variant within differentiated thyroid carcinoma is papillary thyroid carcinoma, also known as PTC. The study investigated the clinical performance of serum hsa_circ_0001955 in predicting the prognosis of PTC treated with radical thyroidectomy and iodine 131 nail clearance. The relative expression of serum circ_0001955 of PTC patients was detected before and after accepting radical thyroidectomy combined with 131I thyroid remnant ablation by RT-qPCR. Serum thyroglobulin (Tg) and thyroglobulin antibody (TgAb) levels were quantified by an automatic chemiluminescence immunoassay analyzer. Multivariate logistic regression analysis was employed to investigate the risk factors associated with the prognosis of PTC patients with postoperative 131I therapy. The serum circ_0001955 levels in 127 PTC patients were higher than that in 96 multinodular goiter patients and 110 healthy controls before treatment and had diagnostic values for PTC patients. After 131I treatment, serum circ_0001955 levels and Tg value have a correlation with potential recurrence (WBS positive). Serum circ_0001955, Tg, and TgAb value, and their combination may have diagnostic value in predicting recurrence. Serum circ_0001955 levels in patients with PTC after radical thyroidectomy and iodine 131 thyroidectomy may help predict recurrence.

Post-transcriptional dynamics and RNA homeostasis in autophagy and cancer

Autophagy is an essential recycling and quality control pathway which preserves cellular and organismal homeostasis. As a catabolic process, autophagy degrades damaged and aged intracellular components in response to conditions of stress, including nutrient deprivation, oxidative and genotoxic stress. Autophagy is a highly adaptive and dynamic process which requires an intricately coordinated molecular control. Here we provide an overview of how autophagy is regulated post-transcriptionally, through RNA processing events, epitranscriptomic modifications and non-coding RNAs. We further discuss newly revealed RNA-binding properties of core autophagy machinery proteins and review recent indications of autophagy's ability to impact cellular RNA homeostasis. From a physiological perspective, we examine the biological implications of these emerging regulatory layers of autophagy, particularly in the context of nutrient deprivation and tumorigenesis.

Hsa_circ_0070440 mediates the prognosis and progress of human prostate cancer

BACKGROUND

This study was designed to explore whether hsa_circ_0070440 was dysregulated in prostate cancer (PCa), and assess the effects of hsa_circ_0070440 alteration on PCa prognosis and cell function.

METHODS

The expression levels of hsa_circ_0070440 were assessed in PCa tissues and cell lines. After the classification of patients with PCa based on mean hsa_circ_0070440 level in 138 cases, Chi-square test and survival analyses (Kaplan-Meier method and multivariable Cox proportional hazards analysis) were performed to assess the predictive value of hsa_circ_0070440 in treatment failure (TTF), time to PSA progression (TTPP) and overall survival time. To examine the function of hsa_circ_0070440 in PCa cells, 22Rv1 and C4-2B cells were used for CCK-8 proliferation and Transwell migration assays. Hsa_circ_0070440- and TXNDC5-specific bindings with miR-382/383-5p were validated by bioinformatic analysis and luciferase gene reporter assay.

RESULTS

An increased expression of hsa_circ_0070440 was found in PCA tissues and cell lines, associated with clinical T stage (p=0.021) and lymph node metastasis. Hsa_circ_0070440 predicted poor overall survival, TTPP, and TTF, acting as independent prognostic factors for overall survival, TTPP, and TTF in patients with PCa. Knockdown of hsa_circ_0070440 inhibited cell proliferation and migration in vitro. Furthermore, hsa_circ_0070440 could sponge miR-382/383-5p. TXNDC5 was a common target gene for miR-382/383-5p in PCa cells.

CONCLUSION

This study demonstrated that hsa_circ_0070440 can predict the prognosis of PCa patients. Hsa_circ_0070440 can facilitate the proliferation and migration of PCa cells, possibly by sponging miR-382/383-5p.

Regulatory role of circular RNAs in the development of therapeutic resistance in the glioma: A double-edged sword

Gliomas are the most common lethal tumors of the brain associated with a poor prognosis and increased resistance to chemo-radiotherapy. Circular RNAs (circRNAs), newly identified noncoding RNAs, have appeared as critical regulators of therapeutic resistance among multiple cancers and gliomas. Since circRNAs are aberrantly expressed in glioma and may act as promoters or inhibitors of therapeutic resistance, we categorized alterations of these specific RNAs expression in therapy resistant-glioma in three different classes, including chemoresistance, radioresistance, and glioma stem cell (GSC)-regulation. circRNAs act as competing endogenous RNA, sponging target microRNA and consequently affecting the expression of genes related to glioma tumorigenesis and resistance. By doing so, circRNAs can modulate the critical cellular pathways and processes regulating glioma resistance, including DNA repair pathways, GSC, epithelial-mesenchymal transition, apoptosis, and autophagy. Considering the poor survival and increased resistance to currently approved treatments for glioma, it is crucial to increase the knowledge of the resistance regulatory effects of circRNAs and their underlying molecular mechanisms. Herein, we conducted a comprehensive search and discussed the existing knowledge regarding the important role eof circRNAs in the emergence of resistance to therapeutic interventions in glioma. This knowledge may serve as a basis for enhancing the effectiveness of glioma therapeutic strategies.

The role of METTL3-mediated CircStk4 modification in the treatment of chronic glomerulonephritis with Qi Teng Xiao Zhuo granule

BACKGROUND

Qi Teng Xiao Zhuo granule (QTXZG), a compound preparation used in traditional Chinese medicine, is a highly effective treatment for chronic glomerulonephritis (CGN). Previously, the mechanism of circStk4 and the N6-methyladenosine (m6A) modification of circStk4 in CGN was elucidated in vivo. Nevertheless, there hasn't been any research done on the connection between circStk4 and QTXZG's mechanism in CGN treatment.

PURPOSE

The current study intended to clarify the molecular mechanism of QTXZG in CGN therapy by both in vitro and in vivo investigations.

METHODS

Mouse mesangial cells (MMCs) were used to measure the rate of proliferation and apoptosis using flow cytometry and the Cell Counting Kit-8 (CCK-8) assay. The expression of markers associated with proliferation, apoptosis, and autophagy was analysed using reverse transcription quantitative PCR (RT-qPCR), western blotting (WB), and immunofluorescence (IF), respectively. Methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) was utilized to analyse the m6A modification of circStk4, and METTL3 expression was assessed using RT-qPCR. Subsequently, miR-133a-3p and C1 expression was examined using RT-qPCR, WB, and IF. Adeno-associated virus 9 (AAV9)-circStk4 knockdown vector and a METTL3 inhibitor were used to explore the roles of METTL3 and circStk4 in CGN. Additionally, molecular docking and cellular thermal shift assays (CETSAs) were performed to assess the binding affinity between METTL3 and the active compounds in QTXZG.

RESULTS

Mechanistically, QTXZG reduced METTL3 expression and decreased circStk4 m6A levels while decreasing circStk4 levels and regulating the miR-133a-3p/C1 axis. Functionally, QTXZG inhibited MMCs and renal tissue proliferation, promoted apoptosis and autophagy, and reduced inflammation. In vivo experiments further confirmed that downregulated ircStk4 and METTL3 expression were accompanied by the therapeutic effects of QTXZG, resulting in a significant attenuation of renal injury, reduction in inflammation, inhibition of renal tissue proliferation and promotion of apoptosis and autophagy.

CONCLUSION

The present study revealed that QTXZG reduced circStk4 m6A and METTL3 expression to regulate the circStk4/miR-133a-3p/C1 axis in the treatment of CGN and thus inhibited glomerular tissue/membrane cell proliferation and promoted autophagy and apoptosis; these results uncovered a new mechanism by which QTXZG reduced CGN and imply that METTL3 might be a target for innovative therapeutic approaches.

Circular RNA hsa_circ_0081343 modulates trophoblast autophagy through Rbm8a nuclear translocation

INTRODUCTION

Fetal growth restriction (FGR) is a kind of obstetric complication that seriously endangers fetal life. Recent studies reported significant reduction of hsa_circ_0081343 in human placenta developed in FGR and is involved in cell migration, invasion, and apoptosis of trophoblast by acting as microRNA sponges. Autophagy is required for invasion of trophoblast cells and for vascular remodeling during placentation. In this study, we aimed to explore the mechanistic link between hsa_circ_0081343 and autophagy.

METHODS

We investigated the interactions between hsa_circ_0081343 and RNA-binding proteins were studied by RNA pull-down assay, mass spectrometry and RNA immunoprecipitation assay. The mechanism of nuclear translocation of Rbm8a were assessed by reverse transcription-quantitative PCR, Western blot, immunofluorescence and Co-Immunoprecipitation. Western blot, immunofluorescence and transmission electron microscopy were performed to elucidate the mechanism underlying hsa_circ_0081343 and/or Rbm8a mediated regulation of autophagy.

RESULTS

hsa_circ_0081343 served as an RNA-binding protein (RBP) sponge. RNA binding motif protein 8A (Rbm8a) was directly bound to hsa_circ_0081343 in the cytoplasm, while knockdown of hsa_circ_0081343 facilitated Rbm8a localization in the nucleus. We also identified Rbm8a as a potential import cargo for Importin13 (Ipo13), which transported Rbm8a across the nuclear membrane into the nucleus. Ipo13 recognized Rbm8a via a functional nuclear localization signal (NLS). Furthermore, the mechanistic study revealed that hsa_circ_0081343-mediated nuclear translocation of Rbm8a activated trophoblast autophagy.

DISCUSSION

Our results suggest that hsa_circ_0081343 could bind to RBP and the interaction between hsa_circ_0081343 and Rbm8a participate in regulating autophagy. These findings offer novel molecular targets and insights for a potential therapeutic strategy against FGR.

METTL3 -mediated m6A modification of circ_0000620 regulates cisplatin sensitivity and apoptosis in lung adenocarcinoma via the MiR-216b-5p/KRAS axis

Circular RNAs (circRNAs) are stable non-coding RNAs characterized by the absence of the conventional 5' cap and 3' polyadenylated tail structure. Its involvement in various aspects of cancers underscores its significance in oncology. Elevated expression of circ_0000620 was observed in both lung adenocarcinoma (LUAD) tissues and cell lines. In vitro, experiments demonstrated that the downregulation of circ_0000620 increased cisplatin sensitivity and promoted cell apoptosis while suppressing malignant characteristics such as cell migration and proliferation. Further investigation into the mechanism underlying the increased expression of circ_0000620 revealed that Methyltransferase 3, N6-Adenosine-Methyltransferase Complex Catalytic Subunit (METTL3) mediates the m6A methylation modification of circ_0000620, thereby promoting its stability and expression. Furthermore, circ_0000620 modulates the miR-216b-5p/KRAS axis to influence apoptosis and cisplatin sensitivity in both A549 and H1299 cell lines. These findings were corroborated by in vivo nude mouse experiments, which showed that knockdown of circ_0000620 inhibited tumor growth and proliferation. In summary, METTL3 plays a role in regulating the stability of circ_0000620 expression, and circ_0000620 exerts its effects on LUAD apoptosis and cisplatin sensitivity through the miR-216b-5p/KRAS signaling pathway.

Circular RNAs in programmed cell death: Regulation mechanisms and potential clinical applications in cancer: A review

Circular RNAs (circRNAs) are a novel class of non-coding RNAs with covalently closed structures formed by reverse splicing of precursor mRNAs. The widespread expression of circRNAs across species has been revealed by high-throughput sequencing and bioinformatics approaches, indicating their unique properties and diverse functions including acting as microRNA sponges and interacting with RNA-binding proteins. Programmed cell death (PCD), encompassing various forms such as apoptosis, necroptosis, pyroptosis, autophagy, and ferroptosis, is an essential process for maintaining normal development and homeostasis in the human body by eliminating damaged, infected, and aging cells. Many studies have demonstrated that circRNAs play crucial roles in tumourigenesis and development by regulating PCD in tumor cells, showing that circRNAs have the potential to be biomarkers and therapeutic targets in cancer. This review aims to comprehensively summarize the intricate associations between circRNAs and diverse PCD pathways in tumor cells, which play crucial roles in cancer development. Additionally, this review provides a detailed overview of the underlying mechanisms by which circRNAs modulate various forms of PCD for the first time. The ultimate objective is to offer valuable insights into the potential clinical significance of developing novel strategies based on circRNAs and PCD for cancer diagnosis, prognosis, and treatment.

Chondrocyte autophagy mechanism and therapeutic prospects in osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis characterized by progressive cartilage degradation, with its pathogenesis closely related to chondrocyte autophagy. Chondrocytes are the only cells in articular cartilage, and the function of chondrocytes plays a vital role in maintaining articular cartilage homeostasis. Autophagy, an intracellular degradation system that regulates energy metabolism in cells, plays an incredibly important role in OA. During the early stages of OA, autophagy is enhanced in chondrocytes, acting as an adaptive mechanism to protect them from various environmental changes. However, with the progress of OA, chondrocyte autophagy gradually decreases, leading to the accumulation of damaged organelles and macromolecules within the cell, prompting chondrocyte apoptosis. Numerous studies have shown that cartilage degradation is influenced by the senescence and apoptosis of chondrocytes, which are associated with reduced autophagy. The relationship between autophagy, senescence, and apoptosis is complex. While autophagy is generally believed to inhibit cellular senescence and apoptosis to promote cell survival, recent studies have shown that some proteins are degraded by selective autophagy, leading to the secretion of the senescence-associated secretory phenotype (SASP) or increased SA-β-Gal activity in senescent cells within the damaged region of human OA cartilage. Autophagy activation may lead to different outcomes depending on the timing, duration, or type of its activation. Thus, our study explored the complex relationship between chondrocyte autophagy and OA, as well as the related regulatory molecules and signaling pathways, providing new insights for the future development of safe and effective drugs targeting chondrocyte autophagy to improve OA.

circCUL3 drives malignant progression of cervical cancer by activating autophagy through sponge miR-223-3p upregulation of ATG7

Circular RNA (circRNA) has emerged as a pivotal regulatory factor in cancer biology, yet its exact role in cervical cancer remains incompletely understood. In this study, we investigated the functional role of circCUL3 in cervical cancer and explored its potential as a therapeutic target. Functional gain and loss experiments were conducted in Hela and Siha cell lines to elucidate the biological functions of circCUL3 in cervical cancer. The results revealed that circCUL3 overexpression significantly enhanced cell viability, migration, and invasion while suppressing apoptosis, while circCUL3 knockout displayed the opposite effects. Mechanistically, we identified hsa-miR-223-3p as a target of circCUL3, with its expression being negatively regulated by circCUL3. Furthermore, we discovered that circCUL3 could sequester miR-223-3p, leading to the upregulation of ATG7 expression, and this was linked to the regulation of autophagy in cervical cancer cells. In vivo validation using a xenograft mouse model further supported our in vitro findings. Notably, we found that chloroquine (CQ), an autophagy inhibitor, restored miR-223-3p expression and counteracted the oncogenic effect of circCUL3 overexpression. In conclusion, circCUL3 potentially contributes to the malignant progression of cervical cancer by acting as a sponge for miR-223-3p, resulting in the upregulation of ATG7 and the activation of autophagy.

GLIDR-mediated regulation of tumor malignancy and cisplatin resistance in non-small cell lung cancer via the miR-342-5p/PPARGC1A axis

BACKGROUND

Lung cancer, particularly non-small cell lung cancer (NSCLC), remains a significant cause of cancer-related mortality, with drug resistance posing a substantial obstacle to effective therapy. LncRNAs have emerged as pivotal regulators of NSCLC progression, suggesting potential targets for cancer diagnosis and treatment. Therefore, identifying new lncRNAs as therapeutic targets and comprehending their underlying regulatory mechanisms are crucial for treating NSCLC.

MATERIALS AND METHODS

RNA-sequencing data from 149 lung adenocarcinoma (LUAD) patients, including 130 responders and 19 nonresponders to primary treatment, were analyzed to identify the most effective lncRNAs. The effects and regulatory pathways of the selected lncRNAs on NSCLC and cisplatin resistance were investigated.

RESULTS

Glioblastoma-downregulated RNA (GLIDR) was the most effective lncRNA in nonresponsive NSCLC patients undergoing primary treatment, and it was highly expressed in NSCLC patients and those with cisplatin-resistant NSCLC. Reducing GLIDR expression enhanced cisplatin sensitivity in resistant NSCLC and decreased the malignant characteristics of NSCLC. Moreover, bioinformatic analysis and luciferase assays revealed that microRNA-342-5p (miR-342-5p) directly targets GLIDR. MiR-342-5p overexpression inhibited NSCLC cell proliferation, migration, and invasion, whereas miR-342-5p inhibition promoted NSCLC malignancy, which was rescued by suppressing GLIDR. Peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PPARGC1A) was identified as a downstream target of miR-342-5p. PPARGC1A inhibition increased cisplatin sensitivity in resistant NSCLC. Moreover, PPARGC1A inhibition suppresses NSCLC malignancy, whereas PPARGC1A overexpression promoted it. Furthermore, GLIDR overexpression was found to counteract the inhibitory effects of miR-342-5p on PPARGC1A, and increased PPARGC1A expression reversed the inhibition of NSCLC malignancies caused by decreased GLIDR.

CONCLUSIONS

GLIDR is a prognostic marker for cisplatin treatment in NSCLC and a therapeutic target in cisplatin-resistant NSCLC. GLIDR promotes NSCLC progression by sponging miR-342-5p to regulate PPARGC1A expression and regulates cisplatin resistance through the miR-342-5p/PPARGC1A axis, underscoring its potential as a therapeutic target in cisplatin-resistant NSCLC.

Biologic activity and treatment resistance to gastrointestinal cancer: the role of circular RNA in autophagy regulation

Circular RNAs (circRNAs) lack the 5'-end methylated guanine cap structure and 3' polyadenylate tail structure, classifying it as a non-coding RNA. With the extensive investigation of circRNA, its role in regulating cell death has garnered significant attention in recent years, establishing it as a recognized participant in cancer's biological processes. Autophagy, an essential pathway in programmed cell death (PCD), involves the formation of autophagosomes using lysosomes to degrade cellular contents under the regulation of various autophagy-related (ATG) genes. Numerous studies have demonstrated that circRNA can modulate the biological activity of cancer cells by influencing the autophagy pathway, exhibiting a dualistic role in suppressing or promoting carcinogenesis. In this review, we comprehensively analyze how autophagy-related circRNA impacts the progression of gastrointestinal cancer (GIC). Additionally, we discuss drug resistance phenomena associated with autophagy regulation in GIC. This review offers valuable insights into exploring potential biological targets for prognosis and treatment strategies related to GIC.

Berberine Protects Against Dihydrotestosterone-Induced Human Ovarian Granulosa Cell Injury and Ferroptosis by Regulating the Circ_0097636/MiR-186-5p/SIRT3 Pathway

Polycystic ovarian syndrome (PCOS) is an endocrine syndrome in women of reproductive age. Berberine (BBR) is a Chinese herbal monomer that exhibits many pharmacological properties related to PCOS treatment. This study aims to analyze the effect of BBR on a cell model of PCOS and the underlying mechanism. Human ovarian granulosa (KGN) cells were treated with dihydrotestosterone (DHT) to mimic a PCOS cell model. The RNA expression of circ_0097636, miR-186-5p, and sirtuin3 (SIRT3) was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was detected by western blotting. Cell viability was analyzed by CCK-8 assay. Cell proliferation and apoptosis were investigated by 5-ethynyl-2'-deoxyuridine (EdU) assay and flow cytometry assay, respectively. The levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) were analyzed by enzyme-linked immunosorbent assays (ELISAs). Fe2+ concentration was assessed by an iron assay kit. Oxidative stress was assessed by detecting reactive oxygen species (ROS) level and malondialdehyde (MDA) level using commercial kits. The association of miR-186-5p with circ_0097636 and SIRT3 was identified by dual-luciferase reporter assay and RNA pull-down assay. Circ_0097636 expression was downregulated in the follicular fluid of PCOS patients and DHT-treated KGN cells when compared with control groups. BBR treatment partially relieved the DHT-induced inhibitory effect on cell proliferation and promoted effects on cell apoptosis, inflammation, ferroptosis, and oxidative stress in KGN cells. Additionally, circ_0097636 bound to miR-186-5p, and SIRT3 was identified as a target gene of miR-186-5p in KGN cells. BBR treatment ameliorated DHT-induced KGN cell injury by upregulating circ_0097636 and SIRT3 expression and downregulating miR-186-5p expression. Moreover, circ_0097636 overexpression protected KGN cells from DHT-induced injury by increasing SIRT3 expression. BBR ameliorated DHT-induced KGN cell injury and ferroptosis by regulating the circ_0097636/miR-186-5p/SIRT3 pathway.

Foot-and-mouth disease virus VP1 degrades YTHDF2 through autophagy to regulate IRF3 activity for viral replication

Many viruses, including foot-and-mouth disease virus (FMDV), can promote the degradation of host proteins through macroautophagy/autophagy, thereby promoting viral replication. However, the regulatory mechanism between autophagy and innate immune responses is not fully understood during FMDV infection. Here, we found that the host GTPBP4/NOG1 (GTP binding protein 4) is a negative regulator of innate immune responses. GTPBP4 deficiency promotes the antiviral innate immune response, resulting in the ability of GTPBP4 to promote FMDV replication. Meanwhile, GTPBP4-deficient mice are more resistant to FMDV infection. To antagonize the host's antiviral immunity, FMDV structural protein VP1 promotes the expression of GTPBP4, and the 209th site of VP1 is responsible for this effect. Mechanically, FMDV VP1 promotes autophagy during virus infection and interacts with and degrades YTHDF2 (YTH N6-methyladenosine RNA binding protein F2) in an AKT-MTOR-dependent autophagy pathway, resulting in an increase in GTPBP4 mRNA and protein levels. Increased GTPBP4 inhibits IRF3 binding to the Ifnb/Ifn-β promoter, suppressing FMDV-induced type I interferon production. In conclusion, our study revealed an underlying mechanism of how VP1 negatively regulates innate immunity through the autophagy pathway, which would contribute to understanding the negative regulation of host innate immune responses and the function of GTPBP4 and YTHDF2 during FMDV infection.Abbreviation: 3-MA:3-methyladenine; ACTB: actin beta; ATG: autophagy related; ChIP:chromatin immunoprecipitation; CQ: chloroquine; DAPI:4',6-diamidino-2-phenylindole; dpi: days post-infection; EV71:enterovirus 71; FMDV: foot-and-mouth disease virus; GTPBP4/NOG1: GTPbinding protein 4; HIF1A: hypoxia inducible factor 1 subunit alpha;hpt:hours post-transfection; IFNB/IFN-β:interferon beta; IRF3: interferon regulatory factor 3; MAP1LC3/LC3:microtubule associated protein 1 light chain 3; MAVS: mitochondriaantiviral signaling protein; MOI: multiplicity of infection; MTOR:mechanistic target of rapamycin kinase; m6A: N(6)-methyladenosine;qPCR:quantitativePCR; SIRT3:sirtuin 3; SQSTM1/p62: sequestosome 1; STING1: stimulator ofinterferon response cGAMP interactor 1; siRNA: small interfering RNA;TBK1: TANK binding kinase 1; TCID50:50% tissue culture infectious doses; ULK1: unc-51 like autophagyactivating kinase 1; UTR: untranslated region; WT: wild type; YTHDF2:YTH N6-methyladenosine RNA binding protein F2.

Human gastric cancer progression and stabilization of ATG2B through RNF5 binding facilitated by autophagy-associated CircDHX8

The role of circDHX8 in the interplay between autophagy and gastric cancer (GC) progression remains unclear. In this study, we investigated the mechanism underlying the role of hsa_circ_003899 (circDHX8) in the malignancy of GC. Differential expression of circRNAs between GC and normal tissues was determined using circle-seq and microarray datasets (GSE83521). These circRNAs were validated using qPCR and Sanger sequencing. The function of circDHX8 was investigated through interference with circDHX8 expression experiments using in vitro and in vivo functional assays. Western blotting, immunofluorescence, and transmission electron microscopy were used to establish whether circDHX8 promoted autophagy in GC cells. To elucidate the mechanism underlying the circDHX8-mediated regulation of autophagy, we performed bioinformatics analysis, RNA pull-down, mass spectrometry (MS), RNA immunoprecipitation (RIP), and other western Blot related experiments. Hsa_circ_0003899 (circDHX8) was identified as upregulated and shown to enhance the malignant progression in GC cells by promoting cellular autophagy. Mechanistically, circDHX8 increased ATG2B protein levels by preventing ubiquitin-mediated degradation, thereby facilitating cell proliferation and invasion in GC. Additionally, circDHX8 directly interacts with the E3 ubiquitin-protein ligase RNF5, inhibiting the RNF5-mediated degradation of ATG2B. Concurrently, ATG2B, an acetylated protein, is subjected to SIRT1-mediated deacetylation, enhancing its binding to RNF5. Consequently, we established a novel mechanism for the role of circDHX8 in the malignant progression of GC.

Hsa_circ_0096157 silencing suppresses autophagy and reduces cisplatin resistance in non-small cell lung cancer by weakening the Nrf2/ARE signaling pathway

BACKGROUND

Non-small cell lung cancer (NSCLC) is the leading cause of cancer morbidity and mortality worldwide, and new diagnostic markers are urgently needed. We aimed to investigate the mechanism by which hsa_circ_0096157 regulates autophagy and cisplatin (DDP) resistance in NSCLC.

METHODS

A549 cells were treated with DDP (0 μg/mL or 3 μg/mL). Then, the autophagy activator rapamycin (200 nm) was applied to the A549/DDP cells. Moreover, hsa_circ_0096157 and Nrf2 were knocked down, and Nrf2 was overexpressed in A549/DDP cells. The expression of Hsa_circ_0096157, the Nrf2/ARE pathway-related factors Nrf2, HO-1, and NQO1, and the autophagy-related factors LC3, Beclin-1, and p62 was evaluated by qRT‒PCR or western blotting. Autophagosomes were detected through TEM. An MTS assay was utilized to measure cell proliferation. The associated miRNA levels were also tested by qRT‒PCR.

RESULTS

DDP (3 μg/mL) promoted hsa_circ_0096157, LC3 II/I, and Beclin-1 expression and decreased p62 expression. Knocking down hsa_circ_0096157 resulted in the downregulation of LC3 II/I and Beclin-1 expression, upregulation of p62 expression, and decreased proliferation. Rapamycin reversed the effect of interfering with hsa_circ_0096157. Keap1 expression was lower, and Nrf2, HO-1, and NQO1 expression was greater in the A549/DDP group than in the A549 group. HO-1 expression was repressed after Nrf2 interference. In addition, activation of the Nrf2/ARE pathway promoted autophagy in A549/DDP cells. Moreover, hsa_circ_0096157 activated the Nrf2/ARE pathway. The silencing of hsa_circ_0096157 reduced Nrf2 expression by releasing miR-142-5p or miR-548n. Finally, we found that hsa_circ_0096157 promoted A549/DDP cell autophagy by activating the Nrf2/ARE pathway.

CONCLUSION

Knockdown of hsa_circ_0096157 inhibits autophagy and DDP resistance in NSCLC cells by downregulating the Nrf2/ARE signaling pathway.

Study on the regulation of trophoblast activity by abnormally expressed hsa_circ_0024838/miR-543/HIF1A in patients with gestational diabetes mellitus

INTRODUCTION

This study aimed to screen circRNAs involved in gestational diabetes mellitus (GDM)-related macrosomia. One differentially expressed circRNA (DEC), hsa_circ_0024838, was further tested for its potential role and mechanism in trophoblasts.

METHODS

DECs in GDM were selected through GSE182737 and GSE194119. The targets were predicted for DECs and microRNAs (miRNAs), to complete the construction of the circRNA-miRNA-gene network. Functional annotation and related biological pathway enrichment analysis were performed on the target genes of miRNAs in the network. Subsequently, the expression levels of hsa_circ_0024838, miR-543, and HIF1A mRNA were identified by real-time quantitative real-time PCR (RT-qPCR) in GDM patients. Trophoblast activity was assessed via CCK-8 assay, apoptosis assay, and Matrigel invasion assay. Finally, interactions between miR-543 and either hsa_circ_0024838 or HIF1A were confirmed using dual-luciferase reporter assays.

RESULTS

A GDM-related circRNA-miRNA-genes interaction network was constructed, consisting of 35 circRNAs, 46 miRNAs, and 122 target genes. Functional enrichment revealed that the enriched pathways were involved in GDM. Hsa_circ_0024838 and HIF1A mRNA expression levels were upregulated in GDM, while miR-543 expression levels were downregulated. A significant positive correlation between hsa_circ_0024838 and newborn weight was observed. Both hsa_circ_0024838 and HIF1A possessed binding sites for miR-543. Overexpressing hsa_circ_0024838 in high-glucose (HG)-cultured trophoblasts can partially reverse HG-induced reduction in trophoblast cell proliferation/migration and increase apoptosis. But this reversal can be negated by co-transfection with miR-543 mimics. The effects of miR-543 can be counteracted by HIF1A.

DISCUSSION

Hsa_circ_0024838 can regulate the expression of HIF1A by interacting with miR-543. This regulates the HIF1A signaling pathway and enhance vitality in trophoblast cells.

Upregulation of circ0000381 attenuates microglial/macrophage pyroptosis after spinal cord injury

Neuroinflammation exacerbates secondary damage after spinal cord injury, while microglia/macrophage pyroptosis is important to neuroinflammation. Circular RNAs (circRNAs) play a role in the central nervous system. However, the functional role and mechanism of circRNAs in regulating microglia/macrophage pyroptosis after spinal cord injury are still poorly studied. In the present study, we detected microglia/macrophage pyroptosis in a female rat model of spinal cord injury, along with upregulated levels of circ0000381 in the spinal cord. Our further experimental results suggest that circ0000381 may function as a sponge to sequester endogenous microRNA423-3p (miR-423-3p), which can increase the expression of NOD-like receptor 3 (NLRP3), a pyroptosis marker. Therefore, upregulation of circ0000381 may be a compensatory change after spinal cord injury to attenuate microglia/macrophage pyroptosis. Indeed, knockdown of circ0000381 expression exacerbated microglia/macrophage pyroptosis. Collectively, our findings provide novel evidence for the upregulation of circ0000381, which may serve as a neuroprotective mechanism to attenuate microglia/macrophage pyroptosis after spinal cord injury. Accordingly, circ0000381 may be a novel therapeutic target for the treatment of spinal cord injury.

Exploring the evolving roles and clinical significance of circRNAs in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) represents the predominant malignancies in the head and neck region, and has limited therapeutic alternatives. Circular RNAs (circRNAs), a substantial category of non-coding RNA molecules, exert influential roles in human disease development and progression, employing various mechanisms such as microRNA sponging, interaction with RNA-binding proteins, and translational capabilities. Accumulating evidence highlights the differential expression of numerous circRNAs in HNSCC, and numerous dysregulated circRNAs underscore their crucial involvement in malignant advancement and resistance to treatment. This review aims to comprehensively outline the characteristics, biogenesis, and mechanisms of circRNAs, elucidating their functional significance in HNSCC. In addition, we delve into the clinical implications of circRNAs, considering their potential as biomarkers or targets for diagnosis, prognosis, and therapeutic applications in HNSCC. The discussion extends to exploring future challenges in the clinical translation of circRNAs, emphasizing the need for further research.

Role of circular RNA as competing endogenous RNA in ovarian cancer (Review)

Circular RNA (circRNA), a type of non‑coding RNA, plays a regulatory role in biological processes. The special loop structure of circRNA makes it highly stable and specific in diseased tissues and cells, especially in tumors. Competing endogenous RNAs (ceRNAs) compete for the binding of microRNA (miRNA) at specific binding sites and thus regulate gene expression. ceRNAs play an important role in various diseases and are currently recognized as the most prominent mechanism of action of circRNAs. circRNAs can modulate the proliferation, migration, invasion and apoptosis of tumor cells through the ceRNA mechanism. With further research, circRNAs may serve as novel markers and therapeutic targets for ovarian cancer (OC). In the present review, the research progress of circRNAs as ceRNAs in OC was summarized, focusing on the effects of the circRNA/miRNA/mRNA axis on the biological functions of OC cells through mediating pivotal signaling pathways. The role of circRNAs in the diagnosis, prognostic assessment and treatment of OC was also discussed in the present review.

CircRNA expression profiles and regulatory networks in the vitreous humor of people with high myopia

Myopia is a global health and economic issue. Circular RNAs (circRNAs) have been shown to play an important role in the pathogenesis of many ocular diseases. We first evaluated the circRNA profiles and possible roles in vitreous humor samples of individuals with high myopia by a competitive endogenous RNA (ceRNA) array. Vitreous humor samples were collected from 15 high myopic (5 for ceRNA array, and 10 for qPCR) and 15 control eyes (5 for ceRNA array, and 10 for qPCR) with idiopathic epiretinal membrane (ERM) and macular hole (MH). 486 circRNAs (339 upregulated and 147 downregulated) and 264 mRNAs (202 upregulated and 62 downregulated) were differentially expressed between the high myopia and control groups. The expression of hsa_circ_0033079 (hsa-circDicer1), hsa_circ_0029989 (hsa-circNbea), hsa_circ_0019072 (hsa-circPank1) and hsa_circ_0089716 (hsa-circEhmt1) were validated by qPCR. Pearson analysis and multivariate regression analysis showed positive and significant correlations for axial length with hsa-circNbea and hsa-circPank1. KEGG analysis showed that the target genes of circRNAs were enriched in the mTOR, insulin, cAMP, and VEGF signaling pathways. GO analysis indicated that circRNAs mainly targeted transcription, cytoplasm, and protein binding. CircRNA-associated ceRNA network analysis and PPI network analysis identified several critical genes for myopia. The expression of circNbea, circPank1, miR-145-5p, miR-204-5p, Nras, Itpr1 were validated by qPCR in the sclera of form-deprivation myopia (FDM) mice model. CircPank1/miR-145-5p/NRAS and circNbea/miR-204-5p/ITPR1 were identified and may be important in the progression of myopia. Our findings suggest that circRNAs may contribute to the pathogenesis of myopia and may serve as potential biomarkers.

WITHDRAWN: The dysregulated autophagy in osteoarthritis: Revisiting molecular profile

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Palmitic acid and trans-4-hydroxy-3-methoxycinnamate, the active ingredients of Yaobishu formula, reduce inflammation and pain by regulating gut microbiota and metabolic changes after lumbar disc herniation to activate autophagy and the Wnt/β-catenin pathway

The imbalance in gut microbiota triggers an inflammatory response that spreads from the gut to the discs and is associated with lumbar disc herniation (LDH). In this study, we investigated the mechanism of palmitic acid (PA) and trans-4-hydroxy-3-methoxycinnamic acid (THMC) on microbiota, metabolic homeostasis, and autophagy after LDH. The LDH rat model was established by puncturing the exposed intervertebral disc. 16S rDNA was used to assess the gut microbiome composition. The microbial metabolites were analyzed by UPLC-MS. The mechanism of PA and THMC in LDH was explored by fecal microbiota transplantation (FMT). We found that Yaobishu, PA, THMC, and the positive control drug Celebrex attenuated intervertebral disc damage in LDH rats and downregulated TRPV1, IL-1β, and IL-18 expression. In addition, Yaobishu reduced Oscillospirales and Ruminococcaceae abundances after LDH. PA increased Bacilli's abundance while decreasing Negativicutes and Ruminococcaceae abundances. Metabolomics showed that Yaobishu increased 2-hexanone, methyl isobutyl ketone, 2-methylpentan-3-one, and nonadecanoic acid levels but decreased pantetheine and urocanate levels. PA and THMC reduced uridine and urocanate levels. Yaobishu, PA, and THMC activated autophagy and the Wnt/β-catenin pathway in LDH rats. Moreover, antibiotics abrogated these effects. FMT-PA and FMT-THMC activated autophagy and decreased IL-1β, IL-18, Wnt1, β-catenin, and TRPV1 expression. FMT-PA and FMT-THMC partially reversed the effects of 3-MA. Taken together, our data suggest that Yaobishu, PA, and THMC relieve inflammation and pain by remodeling the gut microbiota and restoring metabolic homeostasis after LDH to activate autophagy and the Wnt/β-catenin pathway, which provide a new therapeutic target for LDH in the clinic.

Non-coding RNAs regulating endothelial progenitor cells for venous thrombosis: promising therapy and innovation

Venous thromboembolism, which includes deep venous thrombosis (DVT) and pulmonary embolism, is the third most common vascular disease in the world and seriously threatens the lives of patients. Currently, the effect of conventional treatments on DVT is limited. Endothelial progenitor cells (EPCs) play an important role in the resolution and recanalization of DVT, but an unfavorable microenvironment reduces EPC function. Non-coding RNAs, especially long non-coding RNAs and microRNAs, play a crucial role in improving the biological function of EPCs. Non-coding RNAs have become clinical biomarkers of diseases and are expected to serve as new targets for disease intervention. A theoretical and experimental basis for the development of new methods for preventing and treating DVT in the clinic will be provided by studies on the role and molecular mechanism of non-coding RNAs regulating EPC function in the occurrence and development of DVT. To summarize, the characteristics of venous thrombosis, the regulatory role of EPCs in venous thrombosis, and the effect of non-coding RNAs regulating EPCs on venous thrombosis are reviewed. This summary serves as a useful reference and theoretical basis for research into the diagnosis, prevention, treatment, and prognosis of venous thrombosis.

Role of CircCHD2 in the pathogenesis of gestational diabetes mellitus by regulating autophagy via miR-33b-3p/ULK1 axis

Gestational diabetes mellitus (GDM) is a common pregnancy complication with a high incidence in women; however, its pathophysiology remains unknown. Our previous study suggested that the circCHD2/miR-33b-3p/ULK1 axis may be involved in GDM pathogenesis. However, the mechanism through which circCHD2 regulates GDM development requires further investigation. We found that high-glucose (HG, 25 mmol/L) significantly induced the expression of circCHD2, increased autophagy and apoptosis, and decreased cell viability in human placental trophoblast HTR-8/SVneo cells. In contrast, the downregulation of circCHD2 significantly attenuated the effects of HG on HTR-8/SVneo cells. MiR-33b-3p downregulated in the placenta of GDM patients was reduced by HG and detected as a target of circCHD2 using bioinformatics analysis, a dual-luciferase reporter assay, and qRT-PCR assay. Further studies showed that the inhibition of miR-33b-3p significantly blocked the effects of circCHD2 downregulation on cell viability, apoptosis, and autophagy in HG-treated HTR-8/SVneo cells. ULK1 is a target of miR-33b-3p, based on bioinformatics analysis, a dual-luciferase reporter assay, qRT-PCR assay, and Western blot analysis. Compared to miR-33b-3p, ULK1 is upregulated in the placenta of GDM patients. ULK1 overexpression notably blocked the effects of miR-33b-3p mimics on cell viability, apoptosis, and autophagy in HG-treated HTR-8/SVneo cells. These findings suggested that circCHD2 acts as an autophagy promoter via the miR-33b-3p/ULK1 axis to induce apoptosis in HTR-8/SVneo cells, suggesting that circCHD2 is a potential diagnostic and therapeutic target for GDM.

Exosomes from adipose-derived stem cells alleviate premature ovarian failure via blockage of autophagy and AMPK/mTOR pathway

Objective

The objective of this study was to investigate the effects and mechanisms of adipose-derived stem cell-derived exosome (ADSCs-Exo) in treating premature ovarian failure (POF).

Methods

We constructed a POF mouse model through intraperitoneal injection of cyclophosphamide, followed by the administration of the autophagy inhibitor 3-methyladenine (3-MA). Pathological injury, follicle stimulating hormone (FSH), malondialdehyde (MDA), reactive oxygen species (ROS), estradiol (E2), superoxide dismutase (SOD), granulosa cell (GC) apoptosis, and autophagy were assessed. Exosomes isolated from ADSCs were used to treat POF in mice. The AMPK-mTOR pathway and its proteins (p-AMPK and p-mTOR) were evaluated. A POF cell model was established using cyclophosphamide-treated human ovarian granulosa-like tumor (KGN) cells. We administered ADSCs-Exo and rapamycin to validate the mechanism of ADSCs-Exo against POF.

Results

In POF mice, 3-MA treatment attenuated pathological injuries, decreased FSH, MDA, and ROS levels, and increased E2 and SOD levels. 3-MA treatment also inhibited GC apoptosis and autophagy. ADSCs-Exo alleviated pathological injuries, improved ovarian morphology and function, and reduced oxidative stress in POF mice. ADSCs-Exo inhibited GC apoptosis and autophagy. ADSCs-Exo downregulated the expression of AMPK/mTOR pathway proteins (p-AMPK and p-mTOR). In the POF cell model, ADSCs-Exo and rapamycin inhibited AMPK/mTOR-mediated autophagy.

Conclusion

ADSCs-Exo inhibits POF through the inhibition of autophagy and the AMPK/mTOR pathway. This study provides a potential target for the clinical treatment of POF.

Ligustrazine and liguzinediol protect against doxorubicin-induced cardiomyocytes injury by inhibiting mitochondrial apoptosis and autophagy

Preventing or treating heart failure (HF) by blocking cardiomyocyte apoptosis is an effective strategy that improves survival and reduces ventricular remodelling and dysfunction in the chronic stage. Autophagy is a mechanism that degrades intracellular components and compensates for energy deficiency, which is commonly observed in cardiomyocytes of failed hearts. Cardiomyocytes activated by doxorubicin (DOX) exhibit strong autophagy. This study aims to investigate the potential protective effect of ligustrazine and its derivative liguzinediol on regulating DOX-induced cardiomyocyte apoptosis and explore the use of the embryonic rat heart-derived myoblast cell line H9C2 for identifying novel treatments for HF. The results indicated that it has been demonstrated to reverse myocardial infarction remodelling in failed hearts by promoting autophagy in salvaged cardiomyocytes and anti-apoptosis of cardiomyocytes in granulation tissue. Our study suggests that ligustrazine and liguzinediol can be a promising agents and autophagy is potential pathway in the management of HF.

Circ-SFMBT2 sponges miR-224-5p to induce ketamine-induced cystitis by up-regulating metadherin (MTDH)

There is increasing evidence that circular RNAs (circRNAs) play significant roles in various biological processes, yet few reports have examined their roles and molecular mechanisms in ketamine-induced cystitis (KIC). This study examines the possible molecular mechanisms underlying the circRNA-microRNA-mRNA regulatory network in the development of KIC. Transcriptome data were collected, and bioinformatics analysis was conducted to create a circRNA-miRNA-mRNA regulatory network (ceRNA network) associated with the occurrence of KIC. Human bladder epithelial cells (SV-HUC-1) were used in in vitro cell assays. The binding affinity among circ-SFMBT2, miR-224-5p, and Metadherin (MTDH) was identified. To investigate the effects of circ-SFMBT2/miR-224-5p/MTDH on bladder function, KIC mouse models were induced by intraperitoneal injection of ketamine, and gain- or loss-of-function experiments were conducted. Our results demonstrate that MTDH may be a key gene involved in the occurrence of KIC. Both bioinformatics analysis and in vitro cell assays verified that circ-SFMBT2 can competitively bind to miR-224-5p, and miR-224-5p can target and inhibit MTDH. In the bladder tissues of KIC mice, circ-SFMBT2 and MTDH were up-regulated, while miR-224-5p was down-regulated. Animal experiments further confirmed that circ-SFMBT2 can up-regulate MTDH expression by sponging miR-224-5p, thereby exacerbating bladder dysfunction in KIC mice. This study proved that circ-SFMBT2 up-regulates MTDH by competitively binding to miR-224-5p, thereby exacerbating the bladder dysfunction of KIC.

A circRNA-based ceRNA network shows its diagnostic value in non-small-cell lung cancer

BACKGROUND

Numerous studies have reported the vital roles of circular RNA (circRNA)-based competitive endogenous RNA (ceRNA) regulatory networks in cancers. Here, we established a non-small-cell lung cancer (NSCLC)-related circRNA-miRNA-mRNA axis and estimated its diagnostic value in NSCLC.

METHODS

The circ_0061235-miR-3180-5p-PPM1L axis was constructed by small RNA deep sequencing, bioinformatics databases, and preliminary testing. The serum levels of the selected circ_0061235, miR-3180-5p, and PPM1L were quantified using quantitative polymerase chain reaction. Receiver operating characteristic analyses were conducted to evaluate the diagnostic power.

RESULTS

The levels of circ_0061235, miR-3180-5p, and PPM1L showed close correlations according to the ceRNA regulation rule. They were significantly dysregulated in NSCLC and showed the diagnostic ability to discriminate between healthy and NSCLC, and remarkably, between benign lung tumors and NSCLC. Additionally, the down-regulated levels of hsa_circ_0061235, the up-regulated levels of miR-3180-5p, and the decreased levels of PPM1L were correlated to more aggressive features of NSCLC, such as lymph node metastasis, distant metastasis, and higher stages. Intriguingly, compared to the single circ_0061235, miR-3180-5p, PPM1L, and traditional tumor markers, the diverse combinations of circ_0061235, miR-3180-5p, and PPM1L showed much higher sensitivity and specificity to differentiate greater or lesser severity of NSCLC. GO annotation and KEGG pathway analyses revealed the underlying role of the circ_0061235-miR-3180-5p-PPM1L axis in NSCLC.

CONCLUSIONS

We established a specific circRNA-miRNA-mRNA network with higher sensitivity and specificity to diagnose NSCLC, particularly more aggressive NSCLC, providing a new strategy for further developing tumor biomarkers.

Circular RNA vaccine in disease prevention and treatment

CircRNAs are a class of single-stranded RNAs with covalently linked head-to-tail topology. In the decades since its initial discovery, their biogenesis, regulation, and function have rapidly disclosed, permitting a better understanding and adoption of them as new tools for medical applications. With the development of biotechnology and molecular medicine, artificial circRNAs have been engineered as a novel class of vaccines for disease treatment and prevention. Unlike the linear mRNA vaccine which applications were limited by its instability, inefficiency, and innate immunogenicity, circRNA vaccine which incorporate internal ribosome entry sites (IRESs) and open reading frame (ORF) provides an improved approach to RNA-based vaccination with safety, stability, simplicity of manufacture, and scalability. However, circRNA vaccines are at an early stage, and their optimization, delivery and applications require further development and evaluation. In this review, we comprehensively describe circRNA vaccine, including their history and superiority. We also summarize and discuss the current methodological research for circRNA vaccine preparation, including their design, synthesis, and purification. Finally, we highlight the delivery options of circRNA vaccine and its potential applications in diseases treatment and prevention. Considering their unique high stability, low immunogenicity, protein/peptide-coding capacity and special closed-loop construction, circRNA vaccine, and circRNA-based therapeutic platforms may have superior application prospects in a broad range of diseases.

Ferroptosis, autophagy, tumor and immunity

Ferroptosis was first proposed in 2012, a new form of cell death. Autophagy plays a crucial role in cell clearance and maintaining homeostasis. Autophagy is involved in the initial step of ferroptosis under the action of histone elements such as NCOA4, RAB7A, and BECN1. Ferroptosis and autophagy are involved in tumor progression, treatment, and drug resistance in the tumor microenvironment. In this review, we described the mechanisms of ferroptosis, autophagy, and tumor and immunotherapy, respectively, and emphasized the relationship between autophagy-related ferroptosis and tumor.

circFAM134B is a key factor regulating reticulophagy-mediated ferroptosis in hepatocellular carcinoma

Ferroptosis is an important mode of regulated cell death (RCD). Its inhibition is closely related to therapeutic resistance and poor prognosis in hepatocellular carcinoma (HCC). Previous reports have demonstrated ferroptosis as a biological process highly dependent on selective autophagy, such as ferritinophagy, lipophagy, and clockophagy. Our study also revealed a role for ER-phagy-mediated ferroptosis in HCC cells treated with multi-targeted tyrosine kinase inhibitors (TKIs). In the current study, we found that the homologous circular RNA (circRNA) of the family with sequence similarity 134, member B (FAM134B), hsa_circ_0128505 (was abbreviated as circFAM134B in the present study), was identified to specifically target ER-phagy to promote lenvatinib (LV)-induced ferroptosis using reactive oxygen species (ROS), Fe2+, malondialdehyde (MDA), and western blot (WB) assays in HCC cells. RNA pull-down and mass spectrometry analyses suggested that circFAM134B and FAM134B mRNA were enriched with several common interacting proteins. Among them, poly (A) binding protein cytoplasmic 4 (PABPC4) was identified as the most enriched binding partner. It was proven to be a novel antagonist against the nonsense-mediated mRNA decay (NMD) mechanism. We then applied RNA immunoprecipitation (RIP), RNA pull-down, luciferase reporter, and NMD reporter gene assays to further explore the exact role and underlying mechanism of circFAM134B-PABPC4-FAM134B axis in HCC cells. circFAM134B was confirmed as a sponge that competitively interacted with PABPC4, thereby influencing FAM134B mRNA nonsense decay. Our results provide novel evidences and strategies for the comprehensive treatment of HCC.

Non-coding RNA therapeutics: Towards a new candidate for arsenic-induced liver disease

Arsenic, a metalloid toxicant, has caused serious environmental pollution and is presently a global health issue. Long-term exposure to arsenic causes diverse organ and system dysfunctions, including liver disease. Arsenic-induced liver disease comprises a spectrum of liver pathologies, ranging from hepatocyte damage, steatosis, fibrosis, to hepatocellular carcinoma. Various mechanisms, including an imbalance in redox reactions, mitochondrial dysfunction and epigenetic changes, participate in the pathogenesis of arsenic-induced liver disease. Altered epigenetic processes involved in its initiation and progression. Dysregulated modulations of non-coding RNAs (ncRNAs), including miRNAs, lncRNAs and circRNAs, exert regulating effects on these processes. Here, we have reviewed the underlying pathogenic mechanisms that lead to progressive arsenic-induced liver disease, and we provide a discussion focusing on the effects of ncRNAs on dysfunctions in intercellular communication and on the activation of hepatic stellate cells and malignant transformation of hepatocytes. Further, we have discussed the roles of ncRNAs in intercellular communication via extracellular vesicles and cytokines, and have provided a perspective for the application of ncRNAs as biomarkers in the early diagnosis and evaluation of the pathogenesis of arsenic-induced liver disease. Further investigations of ncRNAs will help us to understand the nature of arsenic-induced liver disease and to identify biomarkers and therapeutic targets.

A new glance at autophagolysosomal-dependent or -independent function of transcriptional factor EB in human cancer

Autophagy-lysosome system plays a variety of roles in human cancers. In addition to being implicated in metabolism, it is also involved in tumor immunity, remodeling the tumor microenvironment, vascular proliferation, and promoting tumor progression and metastasis. Transcriptional factor EB (TFEB) is a major regulator of the autophagy-lysosomal system. With the in-depth studies on TFEB, researchers have found that it promotes various cancer phenotypes by regulating the autophagolysosomal system, and even in an autophagy-independent way. In this review, we summarize the recent findings about TFEB in various types of cancer (melanoma, pancreatic ductal adenocarcinoma, renal cell carcinoma, colorectal cancer, breast cancer, prostate cancer, ovarian cancer and lung cancer), and shed some light on the mechanisms by which it may serve as a potential target for cancer treatment.

Gene SH3BGRL3 regulates acute myeloid leukemia progression through circRNA_0010984 based on competitive endogenous RNA mechanism

Introduction: Acute myeloid leukemia (AML) is a malignant proliferative disease affecting the bone marrow hematopoietic system and has a poor long-term outcome. Exploring genes that affect the malignant proliferation of AML cells can facilitate the accurate diagnosis and treatment of AML. Studies have confirmed that circular RNA (circRNA) is positively correlated with its linear gene expression. Therefore, by exploring the effect of SH3BGRL3 on the malignant proliferation of leukemia, we further studied the role of circRNA produced by its exon cyclization in the occurrence and development of tumors. Methods: Genes with protein-coding function obtained from the TCGA database. we detected the expression of SH3BGRL3 and circRNA_0010984 by real-time quantitative polymerase chain reaction (qRT-PCR). We synthesized plasmid vectors and carried out cell experiments, including cell proliferation, cell cycle and cell differentiation by cell transfection. We also studied the transfection plasmid vector (PLVX-SHRNA2-PURO) combined with a drug (daunorubicin) to observe the therapeutic effect. The miR-375 binding site of circRNA_0010984 was queried using the circinteractome databases, and the relationship was validated by RNA immunoprecipitation and Dual-luciferase reporter assay. Finally, a protein-protein interaction network was constructed with a STRING database. GO and KEGG functional enrichment identified mRNA-related functions and signaling pathways regulated by miR-375. Results: We identified the related gene SH3BGRL3 in AML and explored the circRNA_0010984 produced by its cyclization. It has a certain effect on the disease progression. In addition, we verified the function of circRNA_0010984. We found that circSH3BGRL3 knockdown specifically inhibited the proliferation of AML cell lines and blocked the cell cycle. We then discussed the related molecular biological mechanisms. CircSH3BGRL3 acts as an endogenous sponge for miR-375 to isolate miR-375 and inhibits its activity, increases the expression of its target YAP1, and ultimately activates the Hippo signaling pathway involved in malignant tumor proliferation. Discussion: We found that SH3BGRL3 and circRNA_0010984 are important to AML. circRNA_0010984 was significantly up-regulated in AML and promoted cell proliferation by regulating miR-375 through molecular sponge action.

A protein encoded by circular ZNF609 RNA induces acute kidney injury by activating the AKT/mTOR-autophagy pathway

Autophagy plays a crucial role in the development and progression of ischemic acute kidney injury (AKI). However, the function and mechanism of circular RNAs (circRNAs) in the regulation of autophagy in ischemic AKI remain unexplored. Herein, we find that circ-ZNF609, originating from the ZNF609 locus, is highly expressed in the kidney after ischemia/reperfusion injury, and urinary circ-ZNF609 is a moderate predictor for AKI in heart disease patients. Overexpression of circ-ZNF609 can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis while inhibiting proliferation in HK-2 cells, which is blocked by silencing circ-ZNF609. Mechanistically, circ-ZNF609 encodes a functional protein consisting of 250 amino acids (aa), termed ZNF609-250aa, the overexpression of which can activate AKT3/mTOR signaling and induce autophagy flux impairment and cell apoptosis in HK-2 cells in vitro and in AKI kidneys in vivo. The blockade of AKT and mTOR signaling with pharmacological inhibitors is capable of reversing ZNF609-250aa-induced autophagy flux impairment and cell apoptosis in HK-2 cells. The present study demonstrates that highly expressed circ-ZNF609-encoded ZNF609-250aa induces cell apoptosis and AKI by impairing the autophagy flux via an AKT/mTOR-dependent mechanism. These findings imply that targeting circ-ZNF609 may be a novel therapy for ischemic AKI.

[Research advances on the mechanism of circular RNA in diabetic wound healing]

In recent years, a large number of studies have shown that non-coding RNAs play an important role in wound healing process. Among them, studies on the mechanism of circular RNA (circRNA) have shown that circRNA is closely related to the proliferation of cells related to wound healing, such as endothelial progenitor cells and keratinocytes, and circRNA is also involved in the chronic wound healing process. Based on the introduction of the related concept of circRNA, this paper focuses on the possible regulatory mechanism of circRNA in different stages of diabetic wound healing and summarizes the potential role of circRNA in the process of diabetic peripheral vascular atherosclerosis, aiming to explore the in-depth molecular mechanism and clinical significance of circRNA in diabetic wound healing process, and provide reference for further research.

Application prospect of circular RNA-based neoantigen vaccine in tumor immunotherapy

Neoantigen is a protein produced by mutant gene, which is only expressed in tumor cells. It is an ideal target for therapeutic tumor vaccines. Although synthetic long peptide (SLP)-based neoantigen vaccine, DNA-based neoantigen vaccine, and mRNA-based neoantigen vaccine are all in the development stage, they have some inherent shortcomings. Therefore, researchers turned their attention to a new type of "non-coding RNA (ncRNA)", circular RNA (circRNA), for potential better choice. Because of its unique high stability and protein-coding capacity, circRNA is a promising target in the field of neoantigen vaccine. In this paper, we reviewed the feasibility of circRNA encoding neoantigens, summarized the construction process, explained the mechanism of circRNA vaccine in vitro, and discussed the advantages and disadvantages of circRNA vaccine and possible combination with other immunotherapies.

Analysis and verification of the circRNA regulatory network RNO_CIRCpedia_ 4214/RNO-miR-667-5p/Msr1 axis as a potential ceRNA promoting macrophage M2-like polarization in spinal cord injury

BACKGROUND

CircRNAs are involved in the pathogenesis of several central nervous system diseases. However, their functions and mechanisms in spinal cord injury (SCI) are still unclear. Therefore, the purpose of this study was to evaluate circRNA and mRNA expression profiles in the pathological setting of SCI and to predict the potential function of circRNA through bioinformatics.

METHODS

A microarray-based approach was used for the simultaneous measurement of circRNAs and mRNAs, together with qPCR, fluorescence in situ hybridization, western immunoblotting, and dual-luciferase reporter assays to investigate the associated regulatory mechanisms in a rat SCI model.

RESULTS

SCI was found to be associated with the differential expression of 414 and 5337 circRNAs and mRNAs, respectively. Pathway enrichment analyses were used to predict the primary function of these circRNAs and mRNAs. GSEA analysis showed that differentially expressed mRNAs were primarily associated with inflammatory immune response activity. Further screening of these inflammation-associated genes was used to construct and analyze a competing endogenous RNA network. RNO_CIRCpedia_4214 was knocked down in vitro, resulting in reduced expression of Msr1, while the expression of RNO-miR-667-5p and Arg1 was increased. Dual-luciferase assays demonstrated that RNO_CIRCpedia_4214 bound to RNO-miR-667-5p. The RNO_CIRCpedia_4214/RNO-miR-667-5p/Msr1 axis may be a potential ceRNA that promotes macrophage M2-like polarization in SCI.

CONCLUSION

Overall, these results highlighted the critical role that circRNAs may play in the pathophysiology of SCI and the discovery of a potential ceRNA mechanism based on novel circRNAs that regulates macrophage polarization, providing new targets for the treatment of SCI.

Systematic identification of potential key microRNAs and circRNAs in the dorsal root ganglia of mice with sciatic nerve injury

Background

Neuropathic pain (NeP) is a pathological condition arising from a lesion or disease affecting the somatosensory system. Accumulating evidence has shown that circular RNAs (circRNAs) exert critical functions in neurodegenerative diseases by sponging microRNAs (miRNAs). However, the functions and regulatory mechanisms of circRNAs as competitive endogenous RNAs (ceRNAs) in NeP remain to be determined.

Methods

The sequencing dataset GSE96051 was obtained from the public Gene Expression Omnibus (GEO) database. First, we conducted a comparison of gene expression profiles in the L3/L4 dorsal root ganglion (DRG) of sciatic nerve transection (SNT) mice (n = 5) and uninjured mice (Control) (n = 4) to define the differentially expressed genes (DEGs). Then, critical hub genes were screened by exploring protein–protein interaction (PPI) networks with Cytoscape software, and the miRNAs bound to them were predicted and selected and then validated by qRT-PCR. Furthermore, key circRNAs were predicted and filtered, and the network of circRNA-miRNA-mRNA in NeP was constructed.

Results

A total of 421 DEGs were identified, including 332 upregulated genes and 89 downregulated genes. Ten hub genes, including IL6, Jun, Cd44, Timp1, and Csf1, were identified. Two miRNAs, mmu-miR-181a-5p and mmu-miR-223-3p, were preliminarily verified as key regulators of NeP development. In addition, circARHGAP5 and circLPHN3 were identified as key circRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that these differentially expressed mRNAs and targeting miRNAs were involved in signal transduction, positive regulation of receptor-mediated endocytosis and regulation of neuronal synaptic plasticity. These findings have useful implications for the exploration of new mechanisms and therapeutic targets for NeP.

Conclusion

These newly identified miRNAs and circRNAs in networks reveal potential diagnostic or therapeutic targets for NeP.

Profiling of circRNA expressions in radiation-treated head and neck cancer cells and the potential role of circPVT1

OBJECTIVE

Radiotherapy is an indispensable treatment modality for head and neck cancers (HNCs). Due to their stable structure, circular RNAs (circRNA) have been implicated as potential biomarkers for clinical use in cancers. The purpose of this study was profiling the circRNA in radiation-treated head and neck cancer cells to identify potential differentially expressed circRNAs.

DESIGN

The effects of radiation on the expression level of circRNAs were investigated in HNCs cells, compared to healthy cell lines. To predict the potential role of circRNAs in HNC patients, tissue expression levels, survival analyses of circRNAs, and circRNA-miRNA network were evaluated using TCGA/CPTAC datasets. Based on expression level in irradiated cells, circPVT1 (plasmacytoma variant translocation 1) was further investigated by sequence analysis.

RESULTS

The study revealed the characterization of differentially expressed circRNAs in cancer cells and that irradiation made significant changes in the expression of circRNAs. These findings suggest that certain circRNAs, especially circPVT1, may be potential biomarkers to monitor radiotherapy effects in patients with HNCs.

CONCLUSIONS

CircRNAs may be promising molecules for improving and understanding radiotherapy efficacy in HNCs.

Targeting and regulation of autophagy in hepatocellular carcinoma: revisiting the molecular interactions and mechanisms for new therapy approaches

Autophagy is an evolutionarily conserved process that plays a role in regulating homeostasis under physiological conditions. However, dysregulation of autophagy is observed in the development of human diseases, especially cancer. Autophagy has reciprocal functions in cancer and may be responsible for either survival or death. Hepatocellular carcinoma (HCC) is one of the most lethal and common malignancies of the liver, and smoking, infection, and alcohol consumption can lead to its development. Genetic mutations and alterations in molecular processes can exacerbate the progression of HCC. The function of autophagy in HCC is controversial and may be both tumor suppressive and tumor promoting. Activation of autophagy may affect apoptosis in HCC and is a regulator of proliferation and glucose metabolism. Induction of autophagy may promote tumor metastasis via induction of EMT. In addition, autophagy is a regulator of stem cell formation in HCC, and pro-survival autophagy leads to cancer cell resistance to chemotherapy and radiotherapy. Targeting autophagy impairs growth and metastasis in HCC and improves tumor cell response to therapy. Of note, a large number of signaling pathways such as STAT3, Wnt, miRNAs, lncRNAs, and circRNAs regulate autophagy in HCC. Moreover, regulation of autophagy (induction or inhibition) by antitumor agents could be suggested for effective treatment of HCC. In this paper, we comprehensively review the role and mechanisms of autophagy in HCC and discuss the potential benefit of targeting this process in the treatment of the cancer. Video Abstract.

Brain-protective mechanisms of autophagy associated circRNAs: Kick starting self-cleaning mode in brain cells via circRNAs as a potential therapeutic approach for neurodegenerative diseases

Altered autophagy is a hallmark of neurodegeneration but how autophagy is regulated in the brain and dysfunctional autophagy leads to neuronal death has remained cryptic. Being a key cellular waste-recycling and housekeeping system, autophagy is implicated in a range of brain disorders and altering autophagy flux could be an effective therapeutic strategy and has the potential for clinical applications down the road. Tight regulation of proteins and organelles in order to meet the needs of complex neuronal physiology suggests that there is distinct regulatory pattern of neuronal autophagy as compared to non-neuronal cells and nervous system might have its own separate regulator of autophagy. Evidence has shown that circRNAs participates in the biological processes of autophagosome assembly. The regulatory networks between circRNAs, autophagy, and neurodegeneration remains unknown and warrants further investigation. Understanding the interplay between autophagy, circRNAs and neurodegeneration requires a knowledge of the multiple steps and regulatory interactions involved in the autophagy pathway which might provide a valuable resource for the diagnosis and therapy of neurodegenerative diseases. In this review, we aimed to summarize the latest studies on the role of brain-protective mechanisms of autophagy associated circRNAs in neurodegenerative diseases (including Alzheimer's disease, Parkinson's disease, Huntington's disease, Spinal Muscular Atrophy, Amyotrophic Lateral Sclerosis, and Friedreich's ataxia) and how this knowledge can be leveraged for the development of novel therapeutics against them. Autophagy stimulation might be potential one-size-fits-all therapy for neurodegenerative disease as per considerable body of evidence, therefore future research on brain-protective mechanisms of autophagy associated circRNAs will illuminate an important feature of nervous system biology and will open the door to new approaches for treating neurodegenerative diseases.

Circ_0000285 regulates nasopharyngeal carcinoma progression through miR-1278/FNDC3B axis

BACKGROUND

Nasopharyngeal carcinoma (NPC) is cancer with high mortality and poor prognosis. Circular RNAs (circRNAs) have been identified in a wide variety of cancers. But the functional mechanism of circ_000285 in NPC remains unclear.

PURPOSE

To decipher the biological function and molecular mechanism of circ_000285 in NPC.

METHODS

Quantitative PCR (RT-qPCR) was applied for detecting the expression of circ_0000285, miR-1278, and FNDC3B. Western blot was used to measure the protein levels of Fibronectin type III domain containing 3B (FNDC3B), Bcl2 associated X (Bax), and B cell leukemia/lymphoma 2 (Bcl2). Cell proliferation, migration, and invasion were analyzed by colony formation, 5-ethynyl-2'-deoxyuridine (EdU), and transwell assays. Cell apoptosis was detected by flow cytometry assays. ELISA assay was used to analyze Caspase-3 activity. Bioinformatics was used to predict, and the target relationship between miR-1278 and circ_0000285 or FNDC3B was verified by luciferase reporter assay. Tumor xenograft models were established to examine how circ_0000285 functions during the mediation of NPC tumor growth in vivo.

RESULTS

Increased circ_0000285 and FNDC3B expressions, and a decreased miR-1278 expression were observed in NPC tissues and cell lines. Knockdown of circ_0000285 inhibited NPC cell proliferation, migration, invasion, and while promoting NPC cell apoptosis in vitro. Circ_0000285 knockdown-mediated anti-tumor effects in NPC cells could be largely reversed by silencing of miR-1278 or overexpression of FNDC3B. Circ_0000285 could up-regulate FNDC3B expression by sponging miR-1278 in NPC cells. Knockdown of circ_0000285 could inhibit tumor growth in vivo.

CONCLUSION

Circ_0000285 upregulates FNDC3B expression by adsorbing miR-1278 to promote NPC development.