Circ-HIPK2 Accelerates Cell Apoptosis and Autophagy in Myocardial Oxidative Injury by Sponging miR-485-5p and Targeting ATG101

Circular RNA regulatory role in pathological cardiac remodelling

Cardiac remodelling involves structural, cellular and molecular alterations in the heart after injury, resulting in progressive loss of heart function and ultimately leading to heart failure. Circular RNAs (circRNAs) are a recently rediscovered class of non-coding RNAs that play regulatory roles in the pathogenesis of cardiovascular diseases, including heart failure. Thus, a more comprehensive understanding of the role of circRNAs in the processes governing cardiac remodelling may set the ground for the development of circRNA-based diagnostic and therapeutic strategies. In this review, the current knowledge about circRNA origin, conservation, characteristics and function is summarized. Bioinformatics and wet-lab methods used in circRNA research are discussed. The regulatory function of circRNAs in cardiac remodelling mechanisms such as cell death, cardiomyocyte hypertrophy, inflammation, fibrosis and metabolism is highlighted. Finally, key challenges and opportunities in circRNA research are discussed, and orientations for future work to address the pharmacological potential of circRNAs in heart failure are proposed. LINKED ARTICLES: This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

Circular RNAs in coronary heart disease: From molecular mechanism to promising clinical application (Review)

Coronary heart disease (CHD) remains a leading cause of morbidity and mortality worldwide, posing a substantial public health burden. Despite advancements in treatment, the complex etiology of CHD necessitates ongoing exploration of novel diagnostic markers and therapeutic targets. Circular RNAs (circRNAs), a distinct class of non‑coding RNAs with a covalently closed loop structure, have emerged as significant regulators in various diseases, including CHD. Their high stability, tissue‑specific expression and evolutionary conservation underscore their potential as biomarkers and therapeutic agents in CHD. This review discusses the current knowledge on circRNAs in the context of CHD and explores the molecular mechanisms by which circRNAs influence the pathophysiology of CHD, including cardiomyocyte death, endothelial injury, vascular dysfunction and inflammation. It also summarizes the emerging evidence highlighting the differential expression of circRNAs in patients with CHD and their potential utilities as non‑invasive diagnostic and prognostic biomarkers and therapeutic targets for this disease.

Regulatory axis of circular RNA DTNB, microRNA-485-5p, and myeloid cell leukemia 1 attenuates inflammation and apoptosis in caerulein-treated AR42J cells

Acute pancreatitis (AP) is an inflammatory disease of the pancreas and the main cause of hospital admissions for gastrointestinal diseases. Here, the work studied the circular RNA DTNB/microRNA-485-5p/MCL1 axis in AP and hoped to unravel the related mechanism. Caerulein exposure replicated an AP model in AR42J cells, and caerulein-mediated expression of circDTNB, miR-485-5p, and MCL1 was recorded. After exposure, cells were intervened with transfection plasmids and tested for LDH release, apoptosis, and inflammation. To determine the interwork of circDTNB, miR-485-5p, and MCL1, prediction results and verification experiments were conducted. Caerulein exposure reduced circDTNB and MCL1, while elevated miR-485-5p levels in AR42J cells. Upregulating circDTNB protected AR42J cells from caerulein-induced LDH cytotoxicity, apoptosis, and inflammation, but circDTNB upregulation-induced protections could be muffled by inhibiting MCL1. On the contrary, downregulating circDTNB further damaged AR42J cells under caerulein exposure, however, this phenomenon could be partially rescued after silencing miR-485-5p. miR-485-5p was mechanistically verified to be a target of circDTNB to mediate MCL1. Overall, the circDTNB/miR-485-5p/MCL1 axis protects inflammatory response and apoptosis in caerulein-exposed AR42J cells, promisingly identifying circDTNB as a novel molecule for AP treatment.

CIRCVMA21-RELATED PATHWAY ALLEVIATES LIPOPOLYSACCHARIDE-INDUCED HK-2 CELL INJURY

ABSTRACT

Background : It is reported that circVMA21 has an inhibition effect on sepsis-induced acute kidney injury (AKI). Therefore, the underlying molecular mechanisms of circVMA21 in AKI are worthy of further investigation. Material and Methods : Lipopolysaccharide (LPS) was used to induce HK2 cell injury. CircVMA21, miR-337-3p and ZEB2 expression was tested by qRT-PCR. Cell growth was detected by CCK8 assay, EdU assay, and flow cytometry. Protein levels were examined by western blot. The levels of inflammatory factors and oxidative stress markers were measured to evaluate cell inflammatory response and oxidative stress. RNA relationship as verified by dual-luciferase reporter assay, RIP assay, and RNA pull-down assay. Results : CircVMA21 had decreased expression in AKI patients. Overexpressed circVMA21 alleviated LPS-induced HK2 cell inflammation, apoptosis, and oxidative stress. Moreover, circVMA21 sponged miR-337-3p, and miR-337-3p targeted ZEB2. The inhibitory effect of circVMA21 on LPS-induced HK2 cell injury was reversed by miR-337-3p overexpression, and ZEB2 overexpression abolished the promotion effect of miR-337-3p on LPS-induced HK2 cell injury. Conclusions : CircVMA21 could inhibit LPS-induced HK2 cell injury via miR-337-3p/ZEB2 axis.

Association of circulating hsa-miRNAs with sarcopenia: the SarcoPhAge study

OBJECTIVE

To identify a microRNA signature associated to sarcopenia in community-dwelling older adults form the SarcoPhAge cohort.

METHODS

In a screening phase by next generation sequencing (NGS), we compared the hsa-miRome expression of 18 subjects with sarcopenia (79.6 ± 6.8 years, 9 men) and 19 healthy subjects without sarcopenia (77.1 ± 6 years, 9 men) at baseline. Thereafter, we have selected eight candidate hsa-miRNAs according to the NGS results and after a critical assessment of previous literature. In a validation phase and by real-time qPCR, we then analyzed the expression levels of these 8 hsa-miRNAs at baseline selecting 92 healthy subjects (74.2 ± 10 years) and 92 subjects with sarcopenia (75.3 ± 6.8 years). For both steps, the groups were matched for age and sex.

RESULTS

In the validation phase, serum has-miRNA-133a-3p and has-miRNA-200a-3p were significantly decreased in the group with sarcopenia vs controls [RQ: relative quantification; median (interquartile range)]: -0.16 (-1.26/+0.90) vs +0.34 (-0.73/+1.33) (p < 0.01) and -0.26 (-1.07/+0.68) vs +0.27 (-0.55/+1.10) (p < 0.01) respectively. Has-miRNA-744-5p was decreased and has-miRNA-151a-3p was increased in the group with sarcopenia vs controls, but this barely reached significance: +0.16 (-1.34/+0.79) vs +0.44 (-0.31/+1.00) (p = 0.050) and  +0.35 (-0.22/+0.90) vs  +0.03 (-0.68/+0.75) (p = 0.054).

CONCLUSION

In subjects with sarcopenia, serum hsa-miRNA-133a-3p and hsa-miRNA-200a-3p expression were downregulated, consistent with their potential targets inhibiting muscle cells proliferation and differentiation.

YTHDF2 alleviates microglia activation via promoting circHIPK2 degradation

Microglial activation is a common cellular dysfunction in central nervous system inflammation, accompanied by abnormal expression of circular RNAs (circRNAs). YTHDF2, a N6-methyladenosine (m6A) reader, is known as a key element in RNA degradation. Here, lipolysaccharide induced microglia activation in mouse cortex and BV2 cells, accompanied by the decreased YTHDF2 and elevated circHIPK2. YTHDF2 overexpression or circHIPK2 knockdown in BV2 microglia inhibited the expressions of iNOS protein, IL-1β mRNA and IL-6 mRNA. Subsequent experiments revealed that YTHDF2 facilitated circHIPK2 degradation, thereby alleviating microglia activation. These findings suggest that YTHDF2 overexpression could serve as a therapeutic approach for inhibiting microglia activation.

CircHIPK2 facilitates phenotypic switching of vascular smooth muscle cells in hypertension

Hypertension is a clinical syndrome characterized by increased systemic arterial blood pressure, affecting about 1.4 billion people currently worldwide with only one in seven cases adequately controlled. It is the main contributing factor of cardiovascular diseases (CVDs), often co-existing with other CVDs risk factors to impair the structure and function of important organs such as heart, brain, and kidney, and ultimately lead to multi-organ failure. Vascular remodeling is a critical process in the development of essential hypertension, and phenotype switching of vascular smooth muscle cells (VSMCs) was reported contributing substantially to vascular remodeling. circHIPK2 is a circular RNA (circRNA) derived from the second exon of homeodomain-interacting protein kinase 2 (HIPK2). Several studies revealed that circHIPK2 functions in various diseases by serving as a microRNA (miRNA) sponge. However, the functional roles and molecular mechanisms of circHIPK2 in VSMC phenotype switching and hypertension are not clear. In the present study, we showed that the expression of circHIPK2 was significantly upregulated in the VSMCs of hypertensive patients. Functional studies showed that circHIPK2 promoted the Angiotensin II (AngII)-induced VSMC phenotype switching by acting as the sponge of miR-145-5p, thereby upregulating the expression of a disintegrin and metalloprotease (ADAM) 17. Collectively, our study provides a new therapeutic target for hypertension.

miR-185-5p / ATG101 axis alleviated intestinal barrier damage in intestinal ischemia reperfusion through autophagy

Objective

Intestinal ischemia-reperfusion (II/R) is a common pathological injury in clinic, and the systemic inflammatory response it causes will lead to multiple organ damage and functional failure. miR-185-5p has been reported to be a regulator of inflammatory response and autophagy, but whether it participates in the regulation of autophagy in II/R is still unclear. Therefore, we aimed to explore the mechanism of miR-185-5p regulating intestinal barrier injury in (II/R).

Methods

Caco-2 cells was induced by oxygen-glucose deprivation/reoxygenation (OGD/R) to establish II/R model. The superior mesenteric artery of C57BL/6 mice was clamped for 45 min and then subjected to reperfusion for 4 h for the establishment of II/R mice model. miR-185-5p mimic, miR-185-5p inhibitor, pcDNA-autophagy-related 101 (ATG101) were respectively transfected into Caco-2 cells. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to assess miR-185-5p expression. Western blot detected the level of ATG101 and tight junction-associated proteins ZO1, Occludin, E-cadherin, β-catenin, as well as autophagy markers ATG5, ATG12, LC3Ⅰ/Ⅱ, Beclin1 and SQSTM1. Transepithelial electrical resistance (TEER) values was detected by a resistance meter. FITC-Dextran was performed to measure cell permeability. 5-ethynyl-2'-deoxyuridine (EDU) staining measured cell proliferation. Transmission electron microscope was conducted to observe autophagosomes. Hematoxylin & eosin (H&E) staining observed the damage of mice intestinal. Immunohistochemistry (IHC) measured the percentage of ki67 positive cells. TdT-mediated dUTP nick-end labeling (TUNEL) assay assessed cell apoptosis in intestinal tissues of II/R. Dual-luciferase assay verified the targeting relationship between miR-185-5p and ATG101.Results miR-185-5p was overexpressed in OGD/R-induced Caco-2 cells and intestinal tissues of II/R mice. Knocking down miR-185-5p markedly promoted autophagy and TEER values, reduced cell permeability, and alleviated intestinal barrier damage. ATG101 was a target of miR-185-5p, and overexpression of ATG101 promoted autophagy and dampened OGD/R-induced intestinal barrier damage. Overexpression of miR-185-5p reversed the effect of overexpressed ATG101 on OGD/R-induced Caco-2 cells.

Conclusion

Knockdown of miR-185-5p enhanced autophagy and alleviated II/R intestinal barrier damage by targeting ATG101.

Activating transcription factor 4 drives the progression of diabetic cardiac fibrosis

AIMS

Diabetic cardiomyopathy (DC) is one of serious complications of diabetic patients. This study investigated the biological function of activating transcription factor 4 (ATF4) in DC.

METHODS AND RESULTS

Streptozotocin-treated mice and high glucose (HG)-exposed HL-1 cells were used as the in vivo and in vitro models of DC. Myocardial infarction (MI) was induced by left coronary artery ligation in mice. Cardiac functional parameters were detected by echocardiography. Target molecule expression was determined by real time quantitative PCR and western blotting. Cardiac fibrosis was observed by haematoxylin and eosin and Masson's staining. Cardiac apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labelling. Activities of superoxide dismutase, glutathione peroxidase, and levels of malonic dialdehyde and reactive oxygen species were used to assess oxidative stress damage. Molecular mechanisms were evaluated by chromatin immunoprecipitation, dual luciferase assay, and co-immunoprecipitation. ATF4 was up-regulated in the DC and MI mice (P < 0.01). Down-regulation of ATF4 improved cardiac function as evidenced by changes in cardiac functional parameters (P < 0.01), inhibited myocardial collagen I (P < 0.001) and collagen III (P < 0.001) expression, apoptosis (P < 0.001), and oxidative stress (P < 0.001) in diabetic mice. Collagen I (P < 0.01) and collagen III (P < 0.01) expression was increased in MI mice, which was reversed by ATF4 silencing (P < 0.05). ATF4 depletion enhanced viability (P < 0.01), repressed apoptosis (P < 0.001), oxidative damage (P < 0.001), and collagen I (P < 0.001), and collagen III (P < 0.001) expression of HG-stimulated HL-1 cells. ATF4 transcriptionally activated Smad ubiquitin regulatory factor 2 (Smurf2, P < 0.001) to promote ubiquitination and degradation of homeodomain interacting protein kinase-2 (P < 0.001) and subsequently caused inactivation of nuclear factor erythroid 2-related factor 2/heme oxygenase 1 pathway (P < 0.001). The inhibitory effects of ATF4 silencing on HG-induced apoptosis (P < 0.01), oxidative injury (P < 0.01), collagen I (P < 0.001), and collagen III (P < 0.001) expression were reversed by Smurf2 overexpression.

CONCLUSIONS

ATF4 facilitates diabetic cardiac fibrosis and oxidative stress by promoting Smurf2-mediated ubiquitination and degradation of homeodomain interacting protein kinase-2 and then inactivation of nuclear factor erythroid 2-related factor 2/heme oxygenase 1 pathway, suggesting ATF4 as a treatment target for DC.

New Insights into Pathophysiology and New Risk Factors for ACS

Cardiovascular disease still represents the main cause of mortality worldwide. Despite huge improvements, atherosclerosis persists as the principal pathological condition, both in stable and acute presentation. Specifically, acute coronary syndromes have received substantial research and clinical attention in recent years, contributing to improve overall patients' outcome. The identification of different evolution patterns of the atherosclerotic plaque and coronary artery disease has suggested the potential need of different treatment approaches, according to the mechanisms and molecular elements involved. In addition to traditional risk factors, the finer portrayal of other metabolic and lipid-related mediators has led to higher and deep knowledge of atherosclerosis, providing potential new targets for clinical management of the patients. Finally, the impressive advances in genetics and non-coding RNAs have opened a wide field of research both on pathophysiology and the therapeutic side that are extensively under investigation.

New developments in non-exosomal and exosomal ncRNAs in coronary artery disease

Aim & methods: Non-exosomal and exosomal ncRNAs have been reported to be involved in the regulation of coronary artery disease (CAD). Therefore, to explore the biological effects of non-exosomal/exosomal ncRNAs in CAD, the authors searched for studies published in the last 3 years on these ncRNAs in CAD and summarized their functions and mechanisms. Results: The authors summarized 120 non-exosomal ncRNAs capable of regulating CAD progression. In clinical studies, 47 non-exosomal and nine exosomal ncRNAs were able to serve as biomarkers for the diagnosis of CAD. Conclusion: Non-exosomal/exosomal ncRNAs are not only able to serve as biomarkers for CAD diagnosis but can also regulate CAD progression through ceRNA mechanisms and are a potential target for early clinical intervention in CAD.

Emerging roles of circRNAs in the pathological process of myocardial infarction

Myocardial infarction (MI) is defined as cardiomyocyte death in a clinical context consistent with ischemic insult. MI remains one of the leading causes of morbidity and mortality worldwide. Although there are a number of effective clinical methods for the diagnosis and treatment of MI, further investigation of novel biomarkers and molecular therapeutic targets is required. Circular RNAs (circRNAs), novel non-coding RNAs, have been reported to function mainly by acting as microRNA (miRNA) sponges or binding to RNA-binding proteins (RBPs). The circRNA-miRNA-mRNA (protein) regulatory pathway regulates gene expression and affects the pathological mechanisms of various diseases. Undoubtedly, a more comprehensive understanding of the relationship between MI and circRNA will lay the foundation for the development of circRNA-based diagnostic and therapeutic strategies for MI. Therefore, this review summarizes the pathophysiological process of MI and various approaches to measure circRNA levels in MI patients, tissues, and cells; highlights the significance of circRNAs in the regulation MI pathogenesis and development; and provides potential clinical insight for the diagnosis, prognosis, and treatment of MI.

Rhophilin rho GTPase binding protein 1-antisense RNA 1 (RHPN1-AS1) promotes ovarian carcinogenesis by sponging microRNA-485-5p and releasing DNA topoisomerase II alpha (TOP2A)

Ovarian cancer (OC) is the most common and lethal gynecological cancer worldwide. Long non-coding RNAs (lncRNAs) and sponging microRNAs (miRNAs) serve as key regulators in the biological processes of OC. We sought to evaluate the effect of the RHPN1-AS1-miR-485-5p-DNA topoisomerase II alpha (TOP2A) axis in regulating OC progression. RHPN1-AS1, miR-485-5p, and TOP2A levels in OC tissues and cells were determined by RT-qPCR. The interaction of RHPN1-AS1/miR-485-5p/TOP2A was assessed using luciferase, RNA immunoprecipitation, and RNA pull-down assays. RHPN1-AS1 silencing allowed us to explore its biological function by measuring cell viability, proliferation, migration, invasion, and apoptosis in OC cells. In vivo experiments were performed to verify the in vitro findings. We found that the RHPN1-AS1 and TOP2A levels were significantly enhanced, whereas the miR-485-5p levels were reduced in OC tissues and cells. RHPN1-AS1 silencing attenuated cell growth, facilitated apoptosis in OC cells, and inhibited tumor growth in vivo. Notably, RHPN1-AS1 negatively regulating miR-485-5p promoted the TOP2A expression in OC cells. In conclusion, RHPN1-AS1 sponging miR-485-5p accelerated the progression of OC by elevating TOP2A expression, which makes it a promising target for the treatment of OC patients.

Long non-coding RNA NORAD aggravates acute myocardial infarction by promoting fibrosis and apoptosis via miR-577/COBLL1 axis

Acute myocardial infarction (AMI) is one of the most common and serious cardiovascular diseases. With high morbidity and mortality, AMI has attracted the most attention. Emerging studies indicated that long noncoding RNAs (lncRNAs) play an important role in the progression of AMI. However, the role of NORAD in AMI remained unclear. The current study aimed to investigate the function and mechanism of NORAD in AMI. Bioinformatics tools and a wide range of assays including RT-qPCR, flow cytometry, TTC staining, western blot, luciferase reporter and caspase-3 activity assays were conducted to investigate the function and mechanism of NORAD in AMI. We found out that NORAD was significantly upregulated in AMI rats. Knockdown of NORAD alleviated H9c2 cell injury by reducing apoptosis and decreasing expression levels of fibrogenic factors. In addition, NORAD inhibition ameliorated AMI in a rat model by decreasing infarct size and fibrosis. We confirmed that NORAD bound to miR-577, which was downregulated in ischemia-reperfusion (I/R) rats and hypoxia-exposed H9c2 cells. Additionally, miR-577 combined with the 3'UTR of COBLL1, which was upregulated in I/R rats and hypoxia-exposed H9c2 cells. At last, rescue assay validated that the suppressive effects of NORAD knockdown on apoptosis and expression levels of fibrogenic factors were counteracted by COBLL1 overexpression. Overall, NORAD aggravates acute myocardial infarction by promoting fibrosis and apoptosis via the miR-577/COBLL1 axis. This novel discovery suggested that NORAD may serve as a potential therapeutic target for AMI patients.

Serum extracellular vesicles containing MIAT induces atrial fibrosis, inflammation and oxidative stress to promote atrial remodeling and atrial fibrillation via blockade of miR-485-5p-mediated CXCL10 inhibition

BACKGROUND

Atrial fibrillation (AF), a supraventricular arrhythmia that impairs cardiac function, is a main source of morbidity and mortality. Serum-derived extracellular vesicles (EVs) have been identified to carry potential biomarker or target for the diagnosis and treatment of AF. We intended to dissect out the role of lncRNA MIAT enriched in serum-derived EVs in AF.

METHODS

MIAT expression was quantified in EVs isolated from serum samples of AF patients. Mouse and cell models of AF were developed after angiotensin II (Ang II) induction. Relationship between MIAT, miR-485-5p, and CXCL10 was identified. Ectopic expression and depletion assays were implemented in Ang II-treated mice or HL-1 cells, or those co-cultured with serum-derived EVs to explore the roles of EV-carried MIAT.

RESULTS

MIAT was upregulated in EVs from serum samples of AF patients. Further analysis indicated that MIAT enriched in serum-derived EVs promoted atrial fibrosis, inflammation and oxidative stress, and aggravated the atrial remodeling and resultant AF. Mechanistically, MIAT bound to miR-485-5p and weakened its inhibitory role on the target CXCL10, which was responsible for the role of serum-derived EV containing MIAT in cellular fibrosis, oxidative stress and inflammation, and atrial remodeling in vivo.

CONCLUSIONS

In conclusion, serum-derived EV containing MIAT facilitates atrial remodeling and exacerbates the AF by abolishing the miR-485-5p-mediated CXCL10 inhibition. This finding aids in the deeper understanding about the pathophysiology of AF.

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.

Circular RNA circACSL1 aggravated myocardial inflammation and myocardial injury by sponging miR-8055 and regulating MAPK14 expression

Myocarditis (MC) is a common, potentially life-threatening inflammatory disease of the myocardium. A growing body of evidence has shown that mitogen-activated protein kinase 14 (MAPK14) participates in the pathogenesis of MC. However, the upstream regulators of MAPK14 remain enigmatic. Circular RNAs (circRNAs) have been identified to play vital roles in the pathophysiology of cardiovascular diseases. Nevertheless, the clinical significance, biological function, and regulatory mechanisms of circRNAs in MC remain poorly understood. In this study, we determined a novel circRNA, circACSL1 (ID: hsa_circ_0071542), which was significantly upregulated in the acute phase of MC, and its dynamic change in expression was related to the progression of MC. We used lipopolysaccharide (LPS) to induce the inflammatory responses in the human cardiomyocytes (HCM) line for in vitro and in cellulo experiments. The pro-inflammatory factors (IL-1β, IL-6, and TNF-α), myocardial injury markers (cTnT, CKMB, and BNP), cell viability, and cell apoptosis were measured to evaluate the extent of myocardial inflammation and myocardial injury level. Functional experiments, including gain-of-function and loss-of-function, were then performed to investigate the pro-inflammatory roles of circACSL1. The results revealed that circACSL1 could aggravate inflammation, myocardial injury, and apoptosis in HCM. Mechanistically, circACSL1 acted as a sponge for miR-8055-binding sites to regulate the downstream target MAPK14 expression. Furthermore, overexpression of miR-8055 rescued the pro-inflammatory effects of circACSL1 on HCM, and the upregulation of MAPK14 induced by circACSL1 was attenuated by miR-8055 overexpression. Knockdown of circACSL1 or overexpression of miR-8055 reduced myocardial inflammation and myocardial injury level and these effects were rescued by overexpression of MAPK14. In summary, our study demonstrated that circACSL1 could aggravate myocardial inflammation and myocardial injury through competitive absorption of miR-8055, thereby upregulating MAPK14 expression. Moreover, circACSL1 may represent a potential novel biomarker for the precise diagnosis of MC and offer a promising therapeutic target for MC treatment.

The influence of circular RNAs on autophagy and disease progression

Circular RNAs (circRNAs) are non-coding RNAs that have attracted considerable attention in recent years. Owing to their distinct circular structure, circRNAs are stable in cells. Autophagy is a catabolic process that helps in the degradation and recycling of harmful or inessential biological macromolecules in cells and enables cells to adapt to stress and changes in the internal and external environments. Evidence has shown that circRNAs influence the course of a disease by regulating autophagy, which indicates that autophagy is involved in the onset and development of various diseases and can affect drug resistance (for example, it affects cisplatin resistance in tumors). In this review, we summarized the role of circRNAs in autophagy and their influence on disease onset and progression as well as drug resistance. The review will expand our understanding of tumors as well as cardiovascular and neurological diseases and also suggest novel therapeutic strategies.Abbreviations: ACR: autophagy-related circRNA; ADSCs: adipogenic mesenchymal stem cells; AMPK: AMP-activated protein kinase; ATG: autophagy related; BCL2: BCL2 apoptosis regulator; BECN1: beclin 1; ceRNA: competing endogenous RNA; circRNA: circular RNA; CMA: chaperone-mediated autophagy; EPCs: endothelial progenitor cells; LE/MVBs: late endosomes/multivesicular bodies; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; NSCLC: non-small cell lung cancer; PDLSCs: periodontal ligament stem cells; PE: phosphatidylethanolamine; PtdIns: phosphatidylinositol; PtdIns3K: phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate 1,2-dipalmitoyl; PTEN: phosphatase and tensin homolog; RBPs: RNA-binding proteins; SiO₂: silicon dioxide; TFEB: transcription factor EB; ULK: unc-51 like autophagy activating kinase 1.