Hsa_circRNA_0054633 is highly expressed in gestational diabetes mellitus and closely related to glycosylation index

Longitudinal observation of tRNA-derived fragments profiles in gestational diabetes mellitus and its diagnostic value

BACKGROUND

Gestational Diabetes Mellitus (GDM) poses significant risks to maternal and fetal health. Current diagnostic methods based on glucose tolerance tests have limitations for early detection. tRNA-derived small RNAs (tsRNAs) have emerged as potential molecular regulators in various diseases, including metabolic disorders. However, the diagnostic value of tsRNAs in plasma for early GDM or postpartum remains unclear.

METHODS

This longitudinal study profiled the expression of tsRNAs across different gestational stages and postpartum in women with GDM (n = 40) and healthy control gestational women (HCs, n = 40). High-throughput small RNA sequencing identified candidate tsRNAs, which were then validated and correlated with clinical biochemical markers such as fasting blood glucose (FBG), HOMA-IR, and GHbA1c.

RESULTS

tRF-1:32-Val-AAC-1-M6, tRF-1:31-Glu-CTC-1-M2, and tRF-1:30-Gly-CCC-1-M4 were consistently upregulated in the GDM group compared to HCs during the second trimester (p < 0.05). Only tRF-1:31-Glu-CTC-1-M2 was highly expressed during the first trimester, and tRF-1:30-Gly-CCC-1-M4 increased during postpartum. tRF-1:31-Glu-CTC-1-M2 showed a significant correlation with FBG levels in the first trimester (R = 0.317, p = 0.047). The expression of tRF-1:30-Gly-CCC-1-M4 was significantly correlated with HOMA-IR (r = 0.65, p < 0.001) and GHBA1c (r = 0.33, p = 0.037) during postpartum. A joint diagnostic model incorporating tsRNAs expression and clinical markers demonstrated enhanced predictive power for GDM (ROC AUC = 0.768).

CONCLUSION

Our results revealed distinct expression patterns of specific tsRNAs in GDM, showcasing their correlation with key metabolic parameters. This underscores their promising role as biomarkers for early prediction and diagnosis of GDM. The integration of tRFs into a composite biomarker panel holds the potential to improve clinical outcomes by enabling personalized risk assessment and targeted interventions.

Circular RNA hsa_circ_0002268 (PHACTR1) Is Specific to Gestational Diabetes Mellitus in a Polish Pregnant Population

Gestational diabetes mellitus (GDM) is an intolerance of carbohydrate of any degree, which appears for the first time or is diagnosed during pregnancy. The objective of this study is to assess the differences in circular RNA (circRNA) in a Polish pregnant population with and without GDM. A total of 62 pregnant women, 34 with GDM and 28 controls, were enrolled in the study. Total RNAs were extracted from plasma and reverse transcription to complementary DNA (cDNA) was performed. A panel covering 271 amplicons, targeting both linear and circular as well as negative control gene transcripts, was used. Next-generation sequencing was used to evaluate the circRNA quantity. Data analysis was performed using the Coverage Analysis plugin in the Torrent Suite Software (Torrent Suite 5.12.3). A two-step normalization was performed by dividing each transcript read count by the total number of reads generated for the sample, followed by dividing the quantity of each transcript by β-actin gene expression. Both circular and linear forms of RNAs were independently evaluated. A total of 57 transcripts were dysregulated between pregnant women with GDM and controls. Most of the targets (n = 25) were downregulated (cut-off ratio below 0.5), and one target showed a trend toward strong upregulation (ratio 1.45). A total of 39 targets were positively correlated with fasting plasma glucose (FPG), but none of the tested targets were correlated with insulin, CRP or HOMA-IR levels. Among the pregnant women with gestational diabetes, the relative quantity of hsa_circ_0002268 (PHACTR1) was approximately 120% higher than among healthy pregnant women: 0.046 [0.022-0.096] vs. 0.021 [0.007-0.047], respectively, (p = 0.0029). Elevated levels of hsa_circ_0002268 (PHACTR1) might be specific to the Polish population of pregnant women with GDM, making it useful as a potential molecular biomarker in the management of GDM in Poland.

The Expression of Circ-Astn1 Inhibits High Glucose Induced Endothelial Progenitor Cell Dysfunction by Activating Autophagy

BACKGROUND

Diabetes mellitus (DM) and complications such as chronic kidney disease and cardiovascular symptoms pose a substantial public health burden. Increasing studies have shown that circular RNAs (circRNAs) regulate many gene expressions that are essential in diverse pathological and biological procedures. However, the roles of particular circRNAs in DM are unclear.

METHODS

In the current investigation, endothelial progenitor cells (EPCs) were used to search for abnormal expression of circRNAs by using high-throughput sequencing under high glucose (HG) conditions. The regulatory mechanisms and targets were then studied through bioinformatics analysis, luciferase reporter analysis, angiogenic differentiation experiments, flow cytometry detection of apoptosis and RT-qPCR analysis.

RESULTS

The circ-Astn1 expression in EPCs decreased after HG treatment. Overexpression or circ-Astn1 suppressed HG induced endothelial cell damage. MicroRNA (miR)-138-5p and SIRT5 were found to be the downstream targets of circ-Astn1 through luciferase reporter analysis. SIRT5 downregulation or miR-138-5p overexpression reversed circ-Astn1's protective effect against HG induced endothelial cell dysfunction, including apoptosis and abnormal vascular differentiation. Furthermore, circ-Astn1 overexpression promoted autophagy activation by increasing SIRT5 expression under HG conditions. Our findings suggest that circ-Astn1 mediated promotion of SIRT5 facilitates autophagy by sponging miR-138-5p.

CONLUSION

Together, our findings show that the overexpression of circ-Astn1 suppresses HG induced endothelial cell damage by targeting miR-138-5p/SIRT5 axis.

Gypenoside A Protects Human Myocardial Cells from Ischemia/Reperfusion Injury via the circ_0010729/miR-370-3p/RUNX1 Axis

Ischemia/reperfusion (I/R) injury is one of the major causes of cardiovascular disease. Gypenoside A (GP), the main active component of Gynostemma pentaphyllum, alleviates myocardial I/R injury. Circular RNAs (circRNAs) and microRNAs (miRNAs) are involved in the I/R injury. We explored the protective effect of GP on human cardiomyocytes (HCMs) via the circ_0010729/miR-370-3p/RUNX1 axis. Overexpression of circ_0010729 abolished the effects of GP on HMC, such as suppression of apoptosis and increase in cell viability and proliferation. Overexpression of miR-370-3p reversed the effect of circ_0010729 overexpression, resulting in the stimulation of HMC viability and proliferation and inhibition of apoptosis. The knockdown of miR-370-3p suppressed the effects of GP in HCMs. RUNX1 silencing counteracted the effect of miR-370-3p knockdown and maintained GP-induced suppression of apoptosis and stimulation of HMC viability and proliferation. The levels of RUNX1 mRNA and protein were reduced in cells expressing miR-370-3p. In conclusion, this study confirmed that GP alleviated the I/R injury of myocardial cell via the circ_0010729/miR-370-3p/RUNX1 axis.

Hsa_circ_0006260 Mediates Trophoblast Function by Fibronectin Type III Domains Containing Protein 5 via Interacting with miR-770-5p

A series of studies have confirmed the relationship between circular RNAs (circRNAs) and metabolic diseases. Hsa_circ_0006260 has been reported to be lowly expressed in the placenta of gestational diabetes mellitus (GDM) patients, but the underlying mechanism and its biological functions remain obscure. Placental tissues were collected from 37 pregnant women with normal glucose tolerance (NGT) and 37 pregnant women with GDM. Expression changes of hsa_circ_0006260 in placentas and high glucose (HG)-stimulated HTR-8/SVneo cells were detected using real-time quantitative polymerase chain reaction. Cell viability and migration were determined by cell counting and transwell assays, respectively. Measurement of cytokines was done by enzyme-linked immunosorbent assay. Cell apoptosis was estimated by flow cytometry assay. The molecular mechanisms were identified using dual-luciferase reporter and RNA-binding protein immunoprecipitation assays. Hsa_circ_0006260 expression was remarkably lowered in GDM patient-derived placentas and HG-stimulated HTR-8/SVneo cells. Functionally, hsa_circ_0006260 overexpression weakened HG-mediated repression of HTR-8/SVneo cell viability and migration, as well as promotion of HTR-8/SVneo cell inflammatory response and apoptosis. Mechanistically, hsa_circ_0006260 functioned as a miR-770-5p decoy to mediate fibronectin type III domains containing protein 5 (FNDC5) expression. Ectopic expression of miR-770-5p weakened hsa_circ_0006260 overexpression-mediated repression of HG-induced HTR-8/SVneo cell dysfunction. Also, FNDC5 knockdown lessened miR-770-5p overexpression-mediated promotion of HG-induced HTR-8/SVneo cell dysfunction. Our findings manifested a novel mechanism by which hsa_circ_0006260 could lower HG-induced HTR-8/SVneo cell dysfunction by upregulating FNDC5 via binding to miR-770-5p, which shed new light on circRNA mediated GDM pathogenesis.

Multiple novel functions of circular RNAs in diabetes mellitus

Circular RNAs (circRNAs), as an emerging group of non-coding RNAs (ncRNAs), have received the attention given evidence indicating that these novel ncRNAs are implicated in various biological processes. Due to the absence of 5' and 3' ends in circ-RNAs, their two ends are covalently bonded together, and they are synthesised from pre-mRNAs in a process called back-splicing, which makes them more stable than linear RNAs. There is accumulating evidence showing that circRNAs play a critical role in the pathogenesis of diabetes mellitus (DM). Moreover, it has been indicated that dysregulation of circRNAs has made them promising diagnostic biomarkers for the detection of DM. Recently, increasing attention has been paid to investigate the mechanisms underlying the DM process. It has been demonstrated that there is a strong correlation between the expression of circRNAs and DM. Hence, our aim is to discuss the crosstalk between circRNAs and DM and its complications.

Clinical relevance of circulating non-coding RNAs in metabolic diseases: Emphasis on obesity, diabetes, cardiovascular diseases and metabolic syndrome

Non-coding RNAs (ncRNAs) participate in the regulation of several cellular processes including transcription, RNA processing and genome rearrangement. The aberrant expression of ncRNAs is associated with several pathological conditions. In this review, we focused on recent information to elucidate the role of various regulatory ncRNAs i.e., micro RNAs (miRNAs), circular RNAs (circRNAs) and long-chain non-coding RNAs (lncRNAs), in metabolic diseases, e.g., obesity, diabetes mellitus (DM), cardiovascular diseases (CVD) and metabolic syndrome (MetS). The mechanisms by which ncRNAs participated in disease pathophysiology were also highlighted. miRNAs regulate the expression of genes at transcriptional and translational levels. circRNAs modulate the regulation of gene expression via miRNA sponging activity, interacting with RNA binding protein and polymerase II transcription regulation. lncRNAs regulate the expression of genes by acting as a protein decoy, miRNA sponging, miRNA host gene, binding to miRNA response elements (MRE) and the recruitment of transcriptional element or chromatin modifiers. We examined the role of ncRNAs in the disease pathogenesis and their potential role as molecular markers for diagnosis, prognosis and therapeutic targets. We showed the involvement of ncRNAs in the onset of obesity and its progression to MetS and CVD. miRNA-192, miRNA-122, and miRNA-221 were dysregulated in all these metabolic diseases. Other ncRNAs, implicated in at least three diseases include miRNA-15a, miRNA-26, miRNA-27a, miRNA-320, and miRNA-375. Dysregulation of ncRNAs increased the risk of development of DM and MetS and its progression to CVD in obese individuals. Hence, these molecules are potential targets to arrest or delay the progression of metabolic diseases.

CircRNAs and RNA-Binding Proteins Involved in the Pathogenesis of Cancers or Central Nervous System Disorders

Circular RNAs (circRNAs), a newly recognized group of noncoding RNA transcripts, have established widespread attention due to their regulatory role in cell signaling. They are covalently closed noncoding RNAs that form a loop, and are typically generated during the splicing of precursor RNAs. CircRNAs are key post-transcriptional and post-translational regulators of gene expression programs that might influence cellular response and/or function. In particular, circRNAs have been considered to function as sponges of specific miRNA, regulating cellular processes at the post-transcription stage. Accumulating evidence has shown that the aberrant expression of circRNAs could play a key role in the pathogenesis of several diseases. Notably, circRNAs, microRNAs, and several RNA-binding proteins, including the antiproliferative (APRO) family proteins, could be indispensable gene modulators, which might be strongly linked to the occurrence of diseases. In addition, circRNAs have attracted general interest for their stability, abundance in the brain, and their capability to cross the blood–brain barrier. Here, we present the current findings and theragnostic potentials of circRNAs in several diseases. With this, we aim to provide new insights to support the development of novel diagnostic and/or therapeutic strategies for these diseases.

Genetics and Epigenetics: Implications for the Life Course of Gestational Diabetes

Gestational diabetes (GDM) is one of the most common complications of pregnancy, affecting as many as one in six pregnancies. It is associated with both short- and long-term adverse outcomes for the mother and fetus and has important implications for the life course of affected women. Advances in genetics and epigenetics have not only provided new insight into the pathophysiology of GDM but have also provided new approaches to identify women at high risk for progression to postpartum cardiometabolic disease. GDM and type 2 diabetes share similarities in their pathophysiology, suggesting that they also share similarities in their genetic architecture. Candidate gene and genome-wide association studies have identified susceptibility genes that are shared between GDM and type 2 diabetes. Despite these similarities, a much greater effect size for MTNR1B in GDM compared to type 2 diabetes and association of HKDC1, which encodes a hexokinase, with GDM but not type 2 diabetes suggest some differences in the genetic architecture of GDM. Genetic risk scores have shown some efficacy in identifying women with a history of GDM who will progress to type 2 diabetes. The association of epigenetic changes, including DNA methylation and circulating microRNAs, with GDM has also been examined. Targeted and epigenome-wide approaches have been used to identify DNA methylation in circulating blood cells collected during early, mid-, and late pregnancy that is associated with GDM. DNA methylation in early pregnancy had some ability to identify women who progressed to GDM, while DNA methylation in blood collected at 26-30 weeks gestation improved upon the ability of clinical factors alone to identify women at risk for progression to abnormal glucose tolerance post-partum. Finally, circulating microRNAs and long non-coding RNAs that are present in early or mid-pregnancy and associated with GDM have been identified. MicroRNAs have also proven efficacious in predicting both the development of GDM as well as its long-term cardiometabolic complications. Studies performed to date have demonstrated the potential for genetic and epigenetic technologies to impact clinical care, although much remains to be done.

Diagnostic accuracy of circular RNA for diabetes Mellitus: a systematic review and diagnostic Meta-analysis

BACKGROUND

This study aimed to investigate the pooled diagnostic ability of circular RNA (circRNA) molecules for diabetes mellitus.

METHODS

We searched PubMed, Scopus, and Web of Science for relevant studies. A total of 2070 participants, including 775 diabetic patients and 1295 healthy individuals, from five studies were included in this meta-analysis. True positive, true negative, false positive, and false negative data were extracted to calculate pooled sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, and area under the receiver operating characteristics curve. The Deeks' funnel plot was applied for publication bias assessment, Cochran's Q test and I2 index were applied for inter-study heterogeneity assessment. Besides, a subgroup analysis was performed for determining the source of heterogeneity between studies. P value < 0.05 was considered significance. All analysis were done by STATA version 14.

RESULTS

CircRNA presented a sensitivity of 76% (95% confidence interval [95%CI]: 66-84%), specificity of 77% (95%CI: 58-89%), positive LR of 3.25 (95%CI: 1.69-6.23), negative LR of 0.31 (95%CI: 0.21-0.46), DOR of 10.41 (95%CI: 4.26-25.41), and AUC of 0.82 (95%CI: 0.79-0.85) for diabetes mellitus detection. More specifically, hsa_circ_0054633 showed a sensitivity of 67% (95%CI: 53-81%) and a specificity of 82% (95%CI: 63-100%).

CONCLUSION

CircRNAs show highly accurate diagnostic capability for type 2 diabetes mellitus and gestational diabetes mellitus. High sensitivity of circRNAs introduces them as potential noninvasive biomarkers for early diagnosis of diabetes mellitus and their high specificity introduces them as potential therapeutic targets by regulation of their expression.

Hypoxia-pretreated ADSC-derived exosome-embedded hydrogels promote angiogenesis and accelerate diabetic wound healing

Accumulating reports indicate that adipose-derived stem cell (ADSC)-originating exosomes (ADSC-Exos) provide a potential strategy for diabetic wound repair. However, the disadvantages of exosomes, such as fast decrease of biological activity and unknown biological mechanisms, limit their clinical application. Herein, hypoxia-pretreated ADSC-Exo (ADSC-HExo)-embedded GelMA hydrogels (GelMA-HExo) were developed via non-covalent force and physical embedding. These materials rapidly converted into a gel state under illumination, thereby adapting to irregular diabetic wounds. The regulatory mechanism of circ-Snhg11 delivery by exosomes in accelerating diabetic wound healing was explored. In vitro, GelMA-HExo hydrogels had a loose porous structure, and a stable degradation and expansion rate. In vivo, GelMA-HExo hydrogels promoted wound healing in diabetic mice. In particular, ADSC-HExos had a good therapeutic effect, in which circ-Snhg11 expression was increased. Furthermore, circ-Snhg11-modified ADSC-Exos increased the migratory, proliferative and blood vessel regeneration potential of vascular endothelial cells (ECs). In addition, overexpression (OE) of NFE2L2-HIF1α or inhibition of miR-144-3p-both of which are members of the miR-144-3p/NFE2L2/HIF1α pathway downstream of circ-Snhg11-reversed the therapeutic effects of circ-Snhg11. In summary, this study explored the effects and downstream targets of hypoxic engineered exosome hydrogels in managing diabetic wound repair. These hydrogels are expected to serve as a new approach for clinical treatment and to have application possibilities in other disease areas. STATEMENT OF SIGNIFICANCE: ADSC-Exo treatment can accelerate diabetic wound healing via circRNA delivery. But how to reverse the problems such as poor mechanical properties, low biological activity, short duration of effect and high risk of sudden release of exosomes needs investigation. We constructed exosome-embedded GelMA (GelMA-Exo) hydrogels and found that GelMA-Exo treatment could significantly promote diabetic wound healing. Further study found that exosomes from hypoxia-pretreated ADSCs (ADSC-HExos) had an enhanced therapeutic effect than normal exosomes. The regulation mechanism study found that circ-Snhg11 delivery from GelMA-HExo incremented survival and maintained endothelial cell (EC) function, possibly via the activation of miR-144-3p/NFE2L2/HIF1α signaling. These findings suggest a new therapeutic strategy for patients with diabetic ulcer.

Circ_FOXP1 promotes the growth and survival of high glucose-treated human trophoblast cells through the regulation of miR-508-3p/SMAD family member 2 pathway

Gestational diabetes mellitus (GDM) is a health risk for pregnant women and infants. Emerging evidence suggests that the deregulation of circular RNAs (circRNAs) is associated with the progression of this disorder. The objective of this study was to investigate the role of circ_FOXP1 in GDM. Cell models of GDM were established by treating human trophoblast cells with high glucose (HG). The expression of circ_FOXP1, miR-508-3p and SMAD family member 2 (SMAD2) mRNA was detected by quantitative real-time PCR (qPCR). Cell proliferation was assessed by EdU assay and MTT assay, and cell cycle and cell apoptosis were determined by flow cytometry assay. The protein levels of proliferation- and apoptosis-related markers and SMAD2 were measured by western blot. The relationship between miR-508-3p and circ_FOXP1 or SMAD2 was validated by dual-luciferase reporter assay or pull-down assay. The expression of circ_FOXP1 was downregulated in HG-treated HTR-8/SVneo cells. Circ_FOXP1 overexpression promoted HG-inhibited HTR-8/SVneo cell proliferation and suppressed HG-induced HTR-8/SVneo cell cycle arrest and apoptosis. Circ_FOXP1 positively regulated the expression of SMAD2 by targeting miR-508-3p. MiR-508-3p was overexpressed in HG-treated HTR-8/SVneo cells, and its overexpression reversed the effects of circ_FOXP1 overexpression. MiR-508-3p inhibition also alleviated HG-induced HTR-8/SVneo cell injuries, while the knockdown of SMAD2 abolished these effects. Collectively, circ_FOXP1 promotes the growth and survival of HG-treated human trophoblast cells through the miR-508-3p/SMAD2 pathway, hinting that circ_FOXP1 was involved in GDM progression.

Melatonin may suppress lung adenocarcinoma progression via regulation of the circular noncoding RNA hsa_circ_0017109/miR-135b-3p/TOX3 axis

Melatonin is a hormone synthesized in the pineal gland and has widespread physiological and pharmacological functions. Moreover, it can activate protective receptor-dependent processes. These processes can prevent tissue carcinogenesis and inhibit malignant tumor progression and metastasis. Therefore, we investigated the regulatory effects of melatonin on dysregulated circular RNAs in human lung adenocarcinoma (LUAD) cells. In this study, we treated LUAD cells with melatonin and measured the expression of hsa_circ_0017109, miR-135b-3p, and TOX3 by quantitative reverse transcription polymerase chain reaction. Colony formation and cell counting kit-8 assays were used to determine cell proliferation. The wound-healing assay and Transwell experiment were carried out to evaluate the migration potential and invasive capacity of LUAD cells. Also, cell apoptosis was detected using a cell apoptosis kit, and protein production was identified by Western blot. It was suggested that melatonin could inhibit LUAD progression in vivo and in vitro, and the role of TOX3 in this process was explored. Additionally, hsa_circ_0017109 was found to sponge miR-135b-3p, a downstream factor of circ_0017109, which was demonstrated to target TOX3 in LUAD cells and could promote the Hippo pathway and epithelial-mesenchymal transition pathway. To summarize, we demonstrated that melatonin decreases the expression of circ_0017109 and suppresses the non-small-cell lung cancer cell migration, invasion, and proliferation through decreasing TOX3 expression via direct activation of miR-135b-3p.

Plasmatic circRNAs Panel to Predict the Risk of Macrosomia in Women with Gestational Diabetes Mellitus

OBJECTIVES

Fetal macrosomia and its associated complications are the most frequent and serious morbidities for infants associated with gestational diabetes mellitus (GDM). In this study, we aimed to determine the expression of circulating circRNAs in humans, which may be promising biomarkers for the diagnosis of GDM or predicting the macrosomia in GDM patients.

DESIGN

A multi-stage validation and risk score formula analysis was applied for validation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 26 circRNAs previously reported highly expressed in placenta tissues or umbilical cord blood of GDM patients during the pregnancy were enrolled. We recruited a total of 200 patients with GDM with or without macrosomia, 200 healthy pregnant woman, and 200 healthy volunteers.

RESULTS

We discovered that four circRNAs including circRNA_1030, circRNA_23658, circRNA_0009049, and circRNA_32231 were upregulated in plasmatic samples of patients with GDM with or without macrosomia in training set and validation set compared with the healthy pregnant woman and healthy volunteers. Further receiver operating characteristic (ROC) curve analysis in risk score formula indicated a high diagnostic ability and area under ROC curve value (AUC) of 0.950 and 0.815 in training set and validation set for predicting GDM from controls group, for predicting macrosomia from GDM, the AUC was 0.975 and 0.820, respectively. The four circRNAs were further investigated with stable expression in human plasma samples.

LIMITATIONS

The study was limited by larger scale of sample validation and the detailed mechanism investigation.

CONCLUSION

The circRNA_1030, circRNA_23658, circRNA_0009049, and circRNA_32231 might be the potential biomarkers for predicting the GDM and macrosomia during the perinatal period.

circMAP3K4 regulates insulin resistance in trophoblast cells during gestational diabetes mellitus by modulating the miR-6795-5p/PTPN1 axis

Background

Insulin resistance (IR) during gestational diabetes mellitus (GDM) has been linked to dysregulated insulin-PI3K/Akt pathway. A defective insulin-PI3K/Akt pathway and dysregulated circular RNA (circRNA) levels have been observed in the placentas of patients with GDM; however, the mechanisms underlying this association remain unclear.

Methods

circRNAs potentially associated with GDM were selected through bioinformatics analysis and initially identified by quantitative real-time PCR (qPCR) in 9 GDM patients and 9 healthy controls, of which circMAP3K4 was further validated in additional 84 samples by qPCR. circMAP3K4 identity and localization were verified. Pearson correlation analysis was applied to evaluate the correlation between circMAP3K4 expression in the placental tissues of GDM patients and IR-related indicators. An IR model of trophoblasts was constructed using glucosamine. Interactions between miR-6795-5p and circMAP3K4 or PTPN1 were confirmed using a dual-luciferase reporter assay. The circMAP3K4/miR-6795-5p/PTPN1 axis and key markers in the insulin-PI3K/Akt pathway in placentas and trophoblasts were evaluated through qRT-PCR, immunofluorescence, and western blotting. The role of circMAP3K4 in glucose metabolism and cell growth in trophoblasts was determined using the glucose uptake and CCK8 assay, respectively.

Results

circMAP3K4 was highly expressed in the placentas of patients with GDM and the IR trophoblast model; this was associated with a dysregulated insulin-PI3K/Akt pathway. circMAP3K4 in the placentas of GDM patients was positively correlated with weight gain during pregnancy and time-glucose area under the curve of OGTT. circMAP3K4 and PTPN1 could both bind to miR-6795-5p. miR-6795-5p and PTPN1 were downregulated and upregulated, respectively, in the placentas of GDM patients and the IR trophoblast model. circMAP3K4 silencing or miR-6795-5p overexpression partially reversed the decrease in glucose uptake, inhibition in cell growth, and downregulated IRS1 and Akt phosphorylation in IR-trophoblasts; this restoration was reversed upon co-transfection with an miR-6795-5p inhibitor or PTPN1.

Conclusion

circMAP3K4 could suppress the insulin-PI3K/Akt signaling pathway via miR-6795-5p/PTPN1 axis, probably contributing to GDM-related IR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03386-8.

Research Advances in the Roles of Circular RNAs in Pathophysiology and Early Diagnosis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) refers to different degrees of glucose tolerance abnormalities that occur during pregnancy or are discovered for the first time, which can have a serious impact on the mother and the offspring. The screening of GDM mainly relies on the oral glucose tolerance test (OGTT) at 24–28 weeks of gestation. The early diagnosis and intervention of GDM can greatly improve adverse pregnancy outcomes. However, molecular markers for early prediction and diagnosis of GDM are currently lacking. Therefore, looking for GDM-specific early diagnostic markers has important clinical significance for the prevention and treatment of GDM and the management of subsequent maternal health. Circular RNA (circRNA) is a new type of non-coding RNA. Recent studies have found that circRNAs were involved in the occurrence and development of malignant tumors, metabolic diseases, cardiovascular and cerebrovascular diseases, etc., and could be used as the molecular marker for early diagnosis. Our previous research showed that circRNAs are differentially expressed in serum of GDM pregnant women in the second and third trimester, placental tissues during cesarean delivery, and cord blood. However, the mechanism of circular RNA in GDM still remains unclear. This article focuses on related circRNAs involved in insulin resistance and β-cell dysfunction, speculating on the possible role of circRNAs in the pathophysiology of GDM under the current research context, and has the potential to serve as early molecular markers for the diagnosis of GDM.

Circulating exosomal hsa_circRNA_0039480 is highly expressed in gestational diabetes mellitus and may be served as a biomarker for early diagnosis of GDM

Background

Gestational diabetes mellitus (GDM) seriously affects the health of mothers and babies, and there are still no effective early diagnostic markers. Therefore, it is necessary to find diagnostic biomarkers for screening GDM in early pregnancy. Circular RNA (circRNA) is more stable than linear RNA, and can be encapsulated in exosomes and participate in the pathological process of various diseases, which makes it a better candidate biomarker for various diseases. In this study, we attempted to identify the exosomal circRNA biomarkers for detecting early GDM.

Methods

We performed microarray analysis to compare the plasma exosomal circRNA expression profiles of three GDM patients 48 h before and 48 h after delivery. The repeatability of the expression of circRNAs were randomly validated by RT-PCR analysis. Pearson correlation analysis was applied to evaluate the correlation between circRNAs and OGTT level. ROC curve was established to assess the diagnostic value of circRNAs for GDM at different stages.

Results

Plasma exosomal hsa_circRNA_0039480 and hsa_circRNA_0026497 were highly expressed in GDM patients before delivery (P < 0.05). The hsa_circRNA_0039480 expression was higher for GDM group than NGT group at different stages, and was also positively correlated with OGTT during the second trimester (P < 0.05). The expression of hsa_circRNA_0026497 was higher for GDM group during the third, and second trimesters. And there was a strong correlation between two circRNAs in GDM patients during the first-trimester (r = 0.496, P = 0.014). Hsa_circRNA_0039480 showed significant diagnostic value in the first, second, and third trimesters of pregnancy (AUC = 0.704, P = 0.005; AUC = 0.898, P < 0.001 and AUC = 0.698, P = 0.001, respectively). Notably, the combination of hsa_circRNA_0039480 and hsa_circRNA_0026497 exhibited promising discriminative effect on GDM in the first trimesters (AUC = 0.754, P < 0.001).

Conclusion

Plasma exosomal hsa_cirRNA_0039480 is highly expressed in GDM patients at different stages and may be served as a candidate biomarker for early detection of GDM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03195-5.

Circular RNAs in Diabetic Nephropathy: Updates and Perspectives

Circular RNAs (circRNAs) are widespread endogenous transcripts lacking 5′-caps and 3′-polyadenylation tails. Their closed-loop structure confers exonuclease resistance and extreme stability. CircRNAs play essential roles in various diseases, including diabetes. Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease and is one of the most common complications of diabetes. CircRNAs are key in DN and therefore important for understanding DN pathophysiology and developing new therapeutic strategies. In the present review, we briefly introduce the characteristics and functions of circRNAs and summarize recent discoveries on how circRNAs participate in DN. Based on these advances, we suggest future perspectives for studying circRNAs in DN to improve DN treatment and management.

Exosomal Circular RNA hsa_circ_0046060 of Umbilical Cord Mesenchymal Stromal Cell Ameliorates Glucose Metabolism and Insulin Resistance in Gestational Diabetes Mellitus via the miR-338-3p/G6PC2 Axis

BACKGROUND

Impaired glucose metabolism and insulin sensitivity have been linked to the pathogenesis of gestational diabetes mellitus (GDM). Exosomes secreted by the umbilical cord mesenchymal stromal cells (UMSCs) and circular RNAs (circRNAs) derived from exosomes have been shown to be associated with the progression of GDM-related complications.

METHODS

UMSCs were isolated from umbilical cords and identified through flow cytometry. Exosomes were isolated from UMSCs and were then characterized. The expression levels of RNA of hsa_circ_0046060, mmu_circ_0002819, and miR-338-3p were determined by quantitative real-time polymerase chain reaction (RT-qPCR). The intracellular glucose intake and glycogen content were measured using a High Sensitivity Glucose Assay Kit and Glycogen Assay Kit, respectively. Bioinformatics analysis and luciferase reporter assay were used to validate interactions among hsa_circ_0046060, miR-338-3p, and G6PC2. The expression of insulin receptor substrate-1 (IRS-1) and its phosphorylated form, (p-IRS-1), as well as G6PC2, was determined through western blotting.

RESULTS

UMSCs and exosomes were successfully isolated and identified. The upregulation of hsa_circ_0046060 decreased the intracellular glucose content in L-02 cells (43.45 vs. 16.87 pM/mg, P=0.0002), whereas shRNA-mediated downregulation reversed this effect (16.87 vs. 33.16 pM/mg, P=0.0011). Mmu_circ_0002819 in mice aggravated dysregulated glucose metabolism (49.88 vs. 21.69 pM/mg, P=0.0031) and insulin sensitivity (0.20 vs. 0.11 mg/mL, P=0.03) in GDM mice, which was abrogated by the knockdown of mmu_circ_0002819. The results of luciferase reporter assay revealed that miR-338-3p and G6PC2 were the potential targets of has_circ_0046060. Western blotting results showed that the reduced activation of IRS-1 induced by GDM (1.25 vs. 0.54, P=0.0001) could be rescued by the administration of si-circ-G-UMSC-EXOs (0.54 vs. 1.17, P=0.0001).

CONCLUSION

Taken together, the inhibition of hsa_circ_0046060 expression in exosomes from GDM-derived UMSCs can alleviate GDM by reversing abnormal glucose metabolism and insulin resistance in vivo and in vitro.

Peripheral Blood circRNA Microarray Profiling Identities hsa_circ_0001831 and hsa_circ_0000867 as Two Novel circRNA Biomarkers for Early Type 2 Diabetic Nephropathy

PURPOSE

Type 2 diabetes mellitus (T2DM) increases the incidence of diabetic nephropathy (DN) and eventually progresses to end-stage renal disease. Circular RNAs (circRNAs) are a class of non-coding RNAs that are promising as diagnostic biomarkers and therapeutic targets for human diseases. The aim of this study was to analyze the differential expression of circRNAs (DECs) in peripheral blood from patients with early type 2 diabetic nephropathy (ET2DN), T2DM and controls, which will facilitate to discover some new biomarkers for ET2DN.

PATIENTS AND METHODS

Twenty ET2DN patients, 20 T2DM patients, and 20 normal controls were included in this study. Blood samples from 3 random subjects of age- and sex-matched patients in each group, respectively, were used to detect circRNA expression profiles by circRNA microarray, and the circRNA expression of remaining subjects was validated by real-time quantitative polymerase chain reaction (qRT-PCR). Further functional assessment was performed by bioinformatic tools.

RESULTS

There were 586 DECs in ET2DN vs T2DM group (249 circRNAs were upregulated and 337 circRNAs were downregulated); 176 circRNAs were upregulated and 101 circRNAs were downregulated in T2DM vs control group; 57 circRNAs were upregulated and 5 circRNAs were downregulated in ET2DN vs control group. The functional and pathway enrichment of DECs were analyzed by GO and KEGG. qRT-PCR results revealed that hsa_circ_0001831 and hsa_circ_0000867 were significantly upregulated in ET2DN group compared to both of T2DM and control group. The ROC curve demonstrated that hsa_circ_0001831 and hsa_circ_0000867 have high sensitivity and specificity associated with ET2DN.

CONCLUSION

Our study showed the expression profiles of circRNAs in ET2DN patients and demonstrated that hsa_circ_0001831 and hsa_circ_0000867 can be used as novel diagnostic biomarkers for ET2DN.

Circular RNAs in diabetes mellitus and its complications

Diabetes mellitus (DM) is an endocrine disorder characterized by a relative or absolute lack of insulin due to the dysfunction or destruction of β-cells. DM is one of the fastest growing challenges to global health in the 21^st century and places a tremendous burden on affected individuals and their families and countries. Although insulin and antidiabetic drugs have been used to treat DM, a radical cure for the disease is unavailable. The pathogenesis of DM remains unclear. Emerging roles of circular RNAs (circRNAs) in DM have become a subject of global research. CircRNAs have been verified to participate in the onset and progression of DM, implying their potential roles as novel biomarkers and treatment tools. In the present review, we briefly introduce the characteristics of circRNAs. Next, we focus on specific roles of circRNAs in type 1 diabetes mellitus, type 2 diabetes mellitus, gestational diabetes mellitus and diabetes-associated complications.

Hsa_circRNA_102682 is closely related to lipid metabolism in gestational diabetes mellitus

OBJECTIVE

To explore the relationship between circular RNA (circRNA) in gestational diabetes mellitus (GDM) and the metabolic profile at the molecular level, and find a biological marker that can predict GDM early.

METHODS

A retrospective case-control study was conducted using data and samples from women treated at a hospital in China between January 10 2018 and February 20 2019. Reverse transcription polymerase chain reaction (qRT-PCR) was used to evaluate the expression level of hsa_circRNA_102682 in serum and analyze its correlation with lipid metabolism parameters.

RESULTS

Advanced age and higher pre-pregnancy body mass index (BMI) during pregnancy are risk factors for GDM. The expression level of hsa_circ_102682 was lower among the cases than the controls (p=.000). The levels of triglyceride, apolipoprotein A1 (APOA1), APOB, and high-density lipoprotein cholesterol (HDL-C) were different between the controls and cases (p<.05). Hsa_circRNA_102682 was significantly correlated with triglycerides, APOA1, APOB, 1-h blood glucose in the serum of GDM patients, and the correlation coefficients were 0.319, 0.314, 0.286, and 0.311, respectively (p<.05). The area under the receiver operating characteristic curve is 0.684 (95% confidence interval 0.611-0.756, p=.0001).

CONCLUSIONS

Hsa_circRNA_102682 may regulate lipid metabolism, participate in the pathogenesis of GDM. It can be used as a marker to predict GDM.

LncRNA OIP5-AS1 Signatures as a Biomarker of Gestational Diabetes Mellitus and a Regulator on Trophoblast Cells

OBJECTIVES

Gestational diabetes mellitus (GDM) is a common disorder in pregnant women. Long noncoding RNA (lncRNA) is a fundamental mediator in the pathogenesis of GDM. The study aimed to detect the clinical importance of lncRNA OIP5-AS1 and its underlying regulation on trophoblast cells.

DESIGN

The expression of OIP5-AS1 and miR-137-3p was assessed by the quantitative real-time PCR technique. The prognostic effect of OIP5-AS1 was analyzed by the receiver operating characteristic curve. The influences of OIP5-AS1 on cells were indicated by cell counting kit-8, transwell experiments, and flow cytometry. Luciferase activity assay was used to identify the target relationships among OIP5-AS1, miR-137-3p, and EZH2.

PARTICIPANTS

A total of 75 pregnant women with GDM who were treated in the Dongying People's Hospital were selected as the GDM group. Besides, 72 pregnant women with non-GDM who underwent physical examination in the same hospital were selected as the control group.

RESULTS

Decreased expression of OIP5-AS1 was confirmed in GDM patients, and the level of OIP5-AS1 could be used as a basis for evaluating GDM patients. Upregulation of OIP5-AS1 ameliorated the viability, migration, invasion, and apoptosis of HG-stimulated HTR-8/SVneo cells by sponging miR-137-3p. EZH2 was a direct target of miR-137-3p.

CONCLUSIONS

OIP5-AS1 level decreased in women with GDM. OIP5-AS1 appeared to help separating GDM patients from healthy pregnant women. The OIP5-AS1/miR-137-3p/EZH2 pathway could exert its function on HG-induced HTR-8/SVneo models.

Circ-Klhl8 overexpression increased the therapeutic effect of EPCs in diabetic wound healing via the miR-212-3p/SIRT5 axis

Previous studies found that hypoxic pretreatment of endothelial progenitor cells (EPCs) prior to transplantation had a greater therapeutic effect than untreated EPCs in promoting diabetic wound healing. However, the exact mechanism is uncertain. Here, circRNA expression in EPCs after hypoxic treatment was investigated. High-throughput sequencing was used to assess abnormal expression by EPCs of circular RNAs (circRNAs) following hypoxic pretreatment. Additionally, an in vivo full-thickness skin defect mouse model was used to assess the effects of transplanted EPCs on diabetic wound closure. Subsequently, the regulatory mechanism and targets were studied. The results showed that circ-Klhl8 overexpression suppressed hyper glucose-induced endothelial cell damage by activating autophagy. MiR-212-3p and SIRT5 were identified as the downstream targets of circ-Klhl8. Circ-Klhl8 overexpression promoted skin wound healing by regulating SIRT5-mediated autophagy. In conclusion, the study found that circ-Klhl8 overexpression increased the EPC therapeutic effect in promoting diabetic wound healing by targeting the miR-212-3p/SIRT5 axis.

Circular RNA FOXP1 relieves trophoblastic cell dysfunction in recurrent pregnancy loss via the miR-143-3p/S100A11 cascade

Recurrent pregnancy loss (RPL) is closely associated with insufficient functions of trophoblastic cells. Circular RNA forkhead box P1 (circFOXP1) can regulate cell activities in different types of diseases. However, its effects on trophoblastic cells and its role in RPL development remain unknown. In this study, gene expressions were detected by RT-qPCR. Protein levels were detected by Western blotting. Trophoblastic cell viability, apoptosis, invasion, and migration were respectively analyzed via CCK-8, flow cytometry, wound healing, and transwell assays. The association between miR–143–3p and circFOXP1 or S100A11 (S100 calcium binding protein A11) was explored and confirmed by bioinformatics prediction and luciferase reporter assay. Herein, miR–143–3p was upregulated in RPL. Furthermore, miR–143–3p upregulation induced apoptosis and suppressed proliferation, epithelial-to-mesenchymal transition (EMT) process, and metastatic capabilities of trophoblastic cells; whereas, miR–143–3p inhibition exert opposite effects. MiR–143–3p targeted S100A11 and was adversely regulated by circFOXP1 expression. S100A11 inhibition partially offset the effect of miR–143–3p knockdown on trophoblastic cell viability, apoptosis, EMT, invasion, and migration. In addition, circFOXP1 competitively combined with miR–143–3p, thus regulating S100A11 expression. Moreover, circFOXP1 regulated trophoblastic cell functions through the miR–143–3p/S100A11 cascade. To sum up, our study, for the first time, demonstrated that circFOXP1 could improve dysfunction of trophoblastic cells through the miR–143–3p/S100A11 axis, providing novel biomarkers and diagnostic targets for RPL.

Exosome-mediated circ_0001846 participates in IL-1β-induced chondrocyte cell damage by miR-149-5p-dependent regulation of WNT5B

AIMS

Osteoarthritis (OA) is the leading cause of physical disability in middle-aged and elderly people globally. Previous studies have revealed that circular RNA (circRNA) is involved in the pathogenesis of OA. In this study, we studied the role of circ_0001846 in interleukin-1β (IL-1β)-induced OA progression.

METHODS

Twenty-one patients with OA and 17 volunteers were recruited for the collection of articular cartilage tissues. The expression of circ_0001846, microRNA-149-5p (miR-149-5p) and Wingless-type MMTV integration site family, member 5B (WNT5B) was detected by quantitative real-time polymerase chain reaction. The protein expression was determined by western blot analysis. Cell viability, apoptosis, invasion and migration were demonstrated by cell counting kit-8, flow cytometry analysis, transwell invasion and wound-healing assays, respectively. The levels of IL-6 and tumor necrosis factor-α were detected by Enzyme-linked immunosorbent assay. The interaction between miR-149-5p and circ_0001846 or WNT5B was predicted by starbase online database, and proved by dual-luciferase reporter and RIP assays.

RESULTS

Circ_0001846 and WNT5B expression were upregulated, while miR-149-5p expression was downregulated in articular cartilage tissues from patients with OA and IL-1β-treated CHON-001 cells compared with normal articular cartilage tissues or untreated CHON-001 cells. Circ_0001846 expression was increased in IL-1β-treated CHON-001 cell exosomes. Circ_0001846 knockdown reversed IL-1β-mediated cell proliferation, apoptosis, migration, invasion, inflammation and extracellular matrix (ECM) degradation in CHON-001 cells. Additionally, circ_0001846 participated in IL-1β-induced chondrocyte cell damage by sponging miR-149-5p. MiR-149-5p mediated IL-1β-induced chondrocyte cell dysfunction by targeting WNT5B. Furthermore, circ_0001846 secretion was mediated by exosomes in IL-1β-treated CHON-001 cells.

CONCLUSION

Exosome-mediated transfer of circ_0001846 modulated IL-1β-induced chondrocyte cell damage by miR-149-5p/WNT5B axis, providing a novel avenue for the therapy of OA.

Overexpression of hsa_circ_0022742 suppressed hyperglycemia-induced endothelial dysfunction by targeting the miR-503-5p/FBXW7 axis

Type I and II diabetes adversely affect the microvasculature of several organs, although the regulatory mechanisms remain unclear. Previous studies have found that differentially expressed circRNAs associated with hyperglycemia (HG) induce endothelial dysfunction. In the present study, high-throughput sequencing was employed to assess abnormal circRNA expression in human umbilical vein endothelial cells (HUVECs) after HG treatment. Then, bioinformatics analysis, luciferase reporting analysis, angiogenic differentiation analysis, flow cytometry, and qRT-PCR analysis were performed to investigate the underlying regulatory mechanism and targets. The results demonstrate that hsa_circ_0022742 expression in HUVECs was decreased by HG treatment and overexpression of hsa_circ_0022742 suppressed HG-induced endothelial dysfunction. Luciferase analysis showed that miR-503-5p and FBXW7 were downstream targets of hsa_circ_0022742. Both overexpression of FBXW7 and inhibition of miR-503-5p reversed the protective effect of hsa_circ_0022742 against HG-induced endothelial dysfunction, including apoptosis, abnormal vascular differentiation, and secretion of inflammatory factors, indicating that hsa_circ_0022742 enhanced FBXW7 expression by sponging miR-503-5p. Taken together, these findings demonstrate that overexpression of hsa_circ_0022742 suppressed HG-induced endothelial dysfunction by targeting the miR-503-5p/FBXW7 axis.

Ribosomal RNA‑depleted RNA sequencing reveals the pathogenesis of refractory Mycoplasma pneumoniae pneumonia in children

Pneumonia caused by Mycoplasma pneumoniae (M. pneumoniae) is a major cause of community-acquired pneumonia in children. In some cases, M. pneumoniae pneumonia (MPP) can develop into refractory MPP (RMPP), which shows no clinical or radiological response to macrolides, and can progress to severe and complicated pneumonia. However, the pathogenesis of RMPP remains poorly understood. The present study aimed to identify target genes that could be used as biomarkers for the clinical diagnosis of early-stage RMPP through high-throughput sequencing technology. The differences in long non-coding (lnc)RNAs, mRNAs and circular (circ)RNAs were examined between whole-blood samples from two patients with non-refractory MPP (NRMPP), two patients with RMPP and three healthy children using ribosomal (r)RNA-depleted RNA-sequencing techniques and an integrated mRNA/circRNA analysis. A total of 17 lncRNAs (four upregulated and 13 downregulated), 18 mRNAs (six upregulated and 12 downregulated) and 24 circRNAs (12 upregulated and 12 downregulated) were the most significantly differentially expressed (P<0.05) between the NRMPP and RMPP groups. Upon functional analysis, the significantly differentially expressed genes encoded by the targeting mRNAs (prostaglandin-endoperoxide synthase 2, IL-8 and fos-like antigen 1) were screened and identified to be enriched in the ‘IL-17 signaling pathway’. Furthermore, the key circRNAs in the NRMPP and RMPP comparative groups were primarily enriched in ‘herpes simplex virus 1 infection’, ‘viral carcinogenesis’ and ‘RNA transport’. In the present study, a comprehensive analysis of the differences between the NRMPP and RMPP cases was performed based on rRNA-depleted RNA-sequencing techniques, and the selected genes and circRNAs may be closely associated with the complex pathogenesis of RMPP.

Hypoxic Pretreatment of Adipose-Derived Stem Cells Accelerates Diabetic Wound Healing via circ-Gcap14 and HIF-1α/VEGF Mediated Angiopoiesis

Background and Objectives

Adipose-derived stem cell (ADSC) transplantation improves stem cell paracrine function and can enhance wound healing. However, in diabetic patients, glucose-associated effects on this function and cell survival lead to impaired wound closure, thereby limiting ADSC transplantation efficiency. The hypoxia-inducible factor HIF-1α has an important protective function during wound healing. Here, we aim to clarify the regulatory mechanism of ADSCs.

Methods and Results

ADSCs were isolated from BALB/C mice adipose samples. We then used high-throughput sequencing to assess abnormal expression of circular RNAs (circRNAs). We also used an in vivo full-thickness skin defect mouse model to assess the effects of transplanted ADSC on diabetic wound closure. Hypoxic pretreatment of ADSCs accelerated diabetic wound closure, which enhanced angiogenic growth factor expression in our mouse model. High-throughput sequencing and RT-qPCR indicated that circ-Gcap14 was upregulated in hypoxic pretreated ADSCs. Similarly, circ-Gcap14 downregulation also decreased the therapeutic effects of ADSCs; however, circ-Gcap14 overexpression increased the effects of ADSC by promoting angiopoiesis. We also used a luciferase reporter assay to confirm that miR-18a-5p and HIF-1α were downstream targets of circ-Gcap14. HIF-1α expression plays an important role in increased VEGF level.

Conclusions

Based on our data, we suggest that circ-Gcap14 plays an important role in accelerating hypoxic ADSC-mediated diabetic wound closure, by enhancing mouse angiogenic growth factor expression and regulating downstream miR-18a-5p/HIF-1α expression.

Hsa_circ_0054633 association of C peptide is related to IL-17 and TNF-α in patients with diabetes mellitus receiving insulin treatment

Background

Chronic inflammation damaged the islet and resulted in dysfunction of T2D. Circular RNA is stable and better for biomarker in many diseases. Here, we aimed to identify potential circular RNA hsa_circ_0054633 that can be a biomarkers for the effects of insulin therapy in T2D.

Methods

In this retrospective case‐control study, patients were from Li Huili Hospital, Ningbo, China, from February 10, 2019, to August 15, 2019. We included 47 healthy adults, 46 new‐onset T2D with insulin resistance, and 51 patients with insulin therapy. Serum inflammation factors were tested by ELISA assays. We selected hsa_circ_0054633 as a candidate biomarker and measured its concentration in serum by qRT‐PCR. The Pearson correlation test was used to evaluate the correlation between this circRNA and clinical variables.

Results

Clinical data indicated that serum C peptide was increased in T2D treatment with insulin. Serum hsa_circ_0054633 was decreased in insulin treatment group. Hsa_circ_0054633 was negative correlated with C peptide (r = −0.2841, p = 0.0433,). IL‐1 and IL‐6, IL‐17, and TNF‐α were higher in T2D patients and decreased after insulin treatment, only IL‐17 and TNF‐α showed a positive correlation to hsa_circ_0054633 (r = 0.4825, p < 0.0001, and r = 0.6190, p < 0.0001). The area under ROC curve was 0.7432, 0.5839, and 0.7573 for Hsa_circ_0054633, C peptide, and their combination.

Conclusion

Hsa_circ_0054633 level was lower in T2D with insulin treatment than untreated and was a negative correlation with C peptide, and positively correlated with IL‐17 and TNF‐α, suggesting that hsa_circ_0054633 may be a potential early indicator of insulin treatment effect to improve inflammation condition.

Hsa_circ_0074371 Regulates Proliferation, Apoptosis, Migration, and Invasion via the miR-582-3p/LRP6 Axis in Trophoblast Cells

Fetal growth restriction (FGR) ranks second among causes of perinatal death. Circular RNA hsa_circ_0074371 (hsa_circ_0074371) is reported to be downregulated in FGR placentae. However, the role and regulatory mechanism of hsa_circ_0074371 in FGR pathogenesis are indistinct. Expression of hsa_circ_0074371, microRNA (miR)-582-3p, and low-density lipoprotein receptor-related protein 6 (LRP6) mRNA in FGR placentae and trophoblast cells (HTR-8/SVneo) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between hsa_circ_0074371 or LRP6 and miR-582-3p was verified by dual-luciferase reporter and/or RNA immunoprecipitation (RIP), RNA pull-down assays. The proliferation, cell cycle progression, apoptosis, migration, and invasion of HTR-8/SVneo cells were evaluated by Cell Counting Kit-8 (CCK-8), flow cytometry, wound healing, or transwell assays. Caspase3 activity was analyzed with a commercial kit. The protein levels of c-myc, cyclinD1, matrix metalloproteinase (MMP) 2, MMP9, and LRP6 were examined by western blotting. We observed that hsa_circ_0074371 and LRP6 were downregulated while miR-582-3p was upregulated in FGR placentae and HTR-8/SVneo cells. Hsa_circ_0074371 modulated LRP6 expression via sponging miR-582-3p. Hsa_circ_0074371 knockdown induced cell cycle arrest, apoptosis, and inhibited cell proliferation, migration, and invasion in HTR-8/SVneo cells. MiR-582-3p inhibitor reversed hsa_circ_0074371 silencing me on proliferation, migration, and invasion of HTR-8/SVneo cells. LRP6 overexpression overturned the inhibitory effect of miR-582-3p mimic on proliferation, migration, and invasion of HTR-8/SVneo cells. In conclusion, hsa_circ_0074371 downregulation inhibited proliferation, migration, and invasion of trophoblast cells via sponging miR-582-3p and decreasing LRP6 expression, providing a new mechanism related to FGR pathogenesis.

Silencing circANKRD36 inhibits streptozotocin-induced insulin resistance and inflammation in diabetic rats by targeting miR-145 via XBP1

BACKGROUND

Diabetes mellitus (DM) is defined as a group of metabolic diseases characterized by hyperglycemia, which results from a deficiency in insulin secretion and/or insulin action. In diabetic patients, type 2 diabetes mellitus (T2DM) is in the majority. We explored the effects of circANKRD36 on streptozotocin (STZ)-induced insulin resistance and inflammation in diabetic rats with the aim of uncovering the underlying mechanism.

METHODS

STZ was used to induce the in vivo T2DM rat model. After circANKRD36 interference, blood glucose, insulin and adiponectin were respectively detected. Hematoxylin and eosin (H&E), enzyme-linked immunosorbent assay (ELISA) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) were conducted to examine inflammation and apoptosis in T2DM rats, and western blot was used for detecting apoptosis-related proteins. The binding relationships among circANKRD36, miR-145 and XBP1 were examined by luciferase reporter assay.

RESULTS

Results showed that circANKRD36 was expressed at a high level in T2DM rats, while silencing circANKRD36 led to decreased blood glucose and insulin, accompanied by increased adiponectin level, and ameliorating insulin resistance. Silencing circANKRD36 alleviated the inflammation and suppressed cell apoptosis in the pancreatic tissues of T2DM rats, which was abated by miR-145 inhibitor. The binding of miR-145 to XBP1 was then confirmed. Additionally, miR-145 inhibitor increased the level of XBP1 in T2DM rats, which was decreased in the presence of circANKRD36 silencing.

CONCLUSION

This study is the first to prove that silencing circANKRD36 inhibits STZ-induced insulin resistance and inflammation in diabetic rats by targeting miR- 145 via XBP1. The results warrant the importance of circRNAs as drug target and thereby pave way for the development of newer therapeutic measures for T2DM.

Circ-PNPT1 contributes to gestational diabetes mellitus (GDM) by regulating the function of trophoblast cells through miR-889-3p/PAK1 axis

BACKGROUND

Gestational diabetes mellitus (GDM) is the most common medical complication of pregnancy. CircRNA polyribonucleotide nucleotidyltransferase 1 (circ-PNPT1) has been found to be abnormally expressed in GDM patients. However, function and mechanism of circ-PNPT1 in GDM remain largely undefined.

METHODS

Levels of circ-PNPT1, microRNA (miR)-889-3p and PAK1 (p21 (RAC1) activated kinase 1) were detected using quantitative real-time polymerase chain reaction and Western blot assays. Cell viability, apoptosis, migration and invasion were determined using cell counting kit-8 assay, flow cytometry, transwell and wound healing assays, respectively. The binding interaction between miR-889-3p and circ-PNPT1 or PAK1 was verified using dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. Exosomes were obtained from culture media by the use of commercial kits and qualified by transmission electron microscopy (TEM).

RESULTS

Circ-PNPT1 was highly expressed in the placental tissues of GDM and high glucose (HG)-induced trophoblast cells. Knockdown of circ-PNPT1 reversed HG-induced arrest of trophoblast cell viability, migration, invasion and the promotion of cell apoptosis. Mechanistically, we confirmed circ-PNPT1 could promote the expression of PAK1, the target of miR-889-3p, by directly sponging miR-889-3p, and circ-PNPT1 regulated HG-induced trophoblast cell dysfunction by miR-889-3p/PAK1 axis. Further studies showed circ-PNPT1 was packaged into exosomes and could be internalized by surrounding trophoblast cells.

CONCLUSION

Circ-PNPT1 promoted HG-induced trophoblast cell biological dysfunction through miR-889-3p/PAK1 axis. Meanwhile, it could be transferred from HG-induced trophoblast cells to surrounding untreated cells via exosomes.

The Role of N6 -Methyladenosine Modified Circular RNA in Pathophysiological Processes

Circular RNA (circRNA) is a type of covalently closed and endogenous non-coding RNA (ncRNA) with tissue- and cell-specific expression patterns generated by a non-canonical splicing event. Previous reports have indicated that circRNAs exert their functions in different ways, thereby participating in various pathophysiological processes. N6 -methyladenosine (m6A) methylation occurs in the N6-position, which is the most abundant and conserved internal transcriptional modification in eukaryotes, including mRNA and ncRNAs. Accumulating evidences confirm that m6A modification also exists in the circRNA and greatly affects the biological functions of circRNA. Their dysregulated expression can be a cause of various pathophysiological processes, such as spermatogenesis, myoblast differentiation, cancer, cardiovascular disease, mental illness and so on. Understanding the role of m6A-modified circRNAs in pathophysiological processes may contribute to better understanding the physiological mechanisms and develop new biomarkers. This review summarizes the regulatory mechanism of m6A modification on circRNA metabolism and the role of m6A-modified circRNAs in pathophysiological processes. This article may pave the way for a better understanding of the role of epigenetically modified circRNAs in pathophysiological process.

Circular RNAs: Expression, localization, and therapeutic potentials

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

Circ_0049447 acts as a tumor suppressor in gastric cancer through reducing proliferation, migration, invasion, and epithelial-mesenchymal transition

BACKGROUND

Although increasing abnormal expression of circular RNAs (circRNAs) has been revealed in various cancers, there were a small number of studies about circRNAs in gastric cancer (GC). Here, we explored the expression and function of a novel circRNA, circ_0049447, in GC.

METHODS

A total of 80 GC tissues and non-tumorous tissues were collected from the First Affiliated Hospital of China Medical University. And all cells were cultured with 10% fetal bovine serum and incubated at 37°C and 5% CO2. The expression of circ_0049447 was quantified by real-time polymerase chain reaction. The biological function of circ_0049447 on proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) was evaluated by cell counting kit-8 (CCK-8), colony formation assay, transwell migration and invasion assay, and Western blotting. Luciferase report assay was used to verify the direct binding between circ_0049447 and predicted microRNA (miRNA). Furthermore, a xenograft mouse model was used to validate the function of circ_0049447 in vivo.

RESULTS

We demonstrated that circ_0049447 was downregulated in GC (P < 0.001). The area under the receiver operating characteristic curve reached 0.838, while sensitivity was 82.3% and specificity was 77.2%. CCK-8 and colony formation assay showed that overexpression of circ_0049447 could inhibit the proliferation (P < 0.05). Transwell migration and invasion assay showed upregulated circ_0049447 could impede migration in GC cells (P < 0.05). In addition, overexpression of circ_0049447 could impede GC cell EMT. Upregulation of miR-324-5p in GC specimens and direct binding between miR-324-5p with circ_0049447 proven by luciferase reporter assay indicated that circ_0049447 may inhibit GC by sponging certain miRNA.

CONCLUSION

Circ_0049447 acts as a tumor suppressor in GC through reducing proliferation, migration, invasion, and EMT, and it is a promising biomarker for diagnosis.

Circular RNAs: Novel potential regulators in embryogenesis, female infertility, and pregnancy-related diseases

Circular RNAs (circRNAs) are endogenous noncoding RNAs with unique cyclic structures. Although they were previously considered as nonfunctional transcription byproducts, numerous studies have demonstrated that circRNAs regulate gene transcription and expression via different mechanisms. Reproductive health influences the quality of life and affects offspring propagation in women. CircRNAs have been found to modify pregnancy-related diseases, gynecologic cancers, polycystic ovary syndrome, aging, gamete, and embryo development. It's promising for circRNAs to be the novel diagnostic and therapeutic targets for multiple reproductive diseases. With the widespread application of assisted reproduction technology (ART), it has been revealed that circRNA identification contributes to estimating the quality of gametes and embryos, reflecting the success rate of ART. CRISPR-Cas9 gene editing technology has enabled the discovery of new roles of circRNAs. So far, the roles of circRNAs in the reproductive system remain poorly defined. In this review, we describe the classification and functions of circRNAs in embryogenesis and the female reproductive system diseases, revealing potential roles of circRNAs physiologically and pathologically. In so-doing, we provide ideas for developing circRNA-based therapeutic treatment and clinical application of various female reproductive system diseases.

circNRIP1 facilitates keloid progression via FXR1‑mediated upregulation of miR‑503‑3p and miR‑503‑5p

Circular nuclear receptor interacting protein 1 (circNRIP1) is implicated in tumor initiation and progression; however, the underlying mechanism of keloid progression is unclear. To the best of our knowledge, the present study is the first to characterize the contribution of circNRIP1 to keloid progression and evaluate the potential underlying molecular mechanisms using keloid-derived fibroblasts. The expression profile of circNRIP1 was confirmed in keloid tissue. The contribution of circNRIP1 to keloid progression was investigated via loss-of-function assays. Furthermore, the molecular mechanism by which circNRIP1 contributes to pre-microRNA (miR)-503 maturation through blocking Fbxo4-mediated Fragile-X mental retardation 1 (FXR1) ubiquitination was verified. Finally, the biological functions of FXR1, miR-503-3p, and miR-503-5p in keloid-derived fibroblast proliferation, apoptosis and extracellular matrix accumulation were confirmed. circNRIP1 was highly expressed in keloid tissue and keloid-derived fibroblasts. Functional analysis showed that circNRIP1 knockdown successfully blocked the proliferation and expression of extracellular matrix-associated proteins while increasing the rate of apoptosis in keloid-derived fibroblasts. Mechanistically, circNRIP1 maintained FXR1 stability by impeding Fbxo4-mediated FXR1 ubiquitination and degradation. Additionally, FXR1 increased the abundance of miR-503-3p and miR-503-5p by contributing to pre-miR-503 maturation. Knockdown of FXR1, miR-503-3p and miR-503-5p also inhibited proliferation and extracellular matrix accumulation in keloid-derived fibroblasts and increased levels of cell apoptosis. Collectively, the present study confirmed that circNRIP1 contributed to pre-miR-503 maturation via blocking Fbxo4-mediated FXR1 ubiquitination and degradation, which facilitates keloid progression. These results indicate that circNRIP1 has potential as a novel therapeutic target for the control and/or treatment of keloids.

PIWI-interacting RNA sequencing profiles in maternal plasma-derived exosomes reveal novel non-invasive prenatal biomarkers for the early diagnosis of nonsyndromic cleft lip and palate

Background

Congenital malformations are common birth defects with high neonatal morbidity and mortality. It is essential to find simpler and more efficient biomarkers for early prenatal diagnosis. Therefore, we investigated PIWI-interacting RNAs (piRNAs) as potential prenatal biomarkers in plasma-derived exosomes from pregnant women carrying foetuses with congenital malformations.

Methods

Small RNA sequencing was used to screen piRNA biomarkers in plasma-derived exosomes of five pregnant women carrying foetuses with nonsyndromic cleft lip and palate (nsCLP) and five women carrying normal foetuses. Differentially expressed piRNAs were verified in 270 pregnant women, including 111 paired women carrying foetuses with congenital malformations and normal foetuses (at 24 gestational weeks), 10 paired women carrying foetuses with nsCLP and normal foetuses (at 15–19 gestational weeks), and 28 women at different stages of normal pregnancy. piRNA biomarkers were also verified in placentas, umbilical cords, fetal medial calf muscles, and lip tissues of nsCLP and normal foetuses.

Findings

We identified a biomarker panel of three pregnancy-associated exosomal piRNAs (hsa-piR-009228, hsa-piR-016659, and hsa-piR-020496) could distinguish nsCLP foetuses from normal foetuses. These three piRNAs had better diagnostic accuracy for nsCLP at the early gestational stage, at which time typical malformations were not detected upon prenatal ultrasound screening, and had diagnostic value for neural tube defects (NTDs) and congenital heart defects (CHDs).

Interpretation

Our work revealed the potential clinical applications of piRNAs for predicting nsCLP, NTDs, and CHDs.

Funding

National Key Research and Development Program, National Natural Science Foundation of China, and LiaoNing Revitalization Talents Program .

Non-Coding RNAs and Extracellular Vehicles: Their Role in the Pathogenesis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset or first recognition in the second or third trimester of pregnancy. GDM has a considerable impact on health outcomes of the mother and offspring during pregnancy, delivery, and beyond. Although the exact mechanism regarding GDM remains unclear, numerous studies have suggested that non-coding RNAs, including long non-coding (lnc)RNAs, microRNAs, and circular RNAs, were involved in the pathogenesis of GDM in which they played vital regulatory roles. Additionally, several studies have revealed that extracellular vehicles also participated in the pathogenesis of GDM, highlighting their important role in this disease. Considering the lack of effective biomarkers for the early identification of and specific treatment for GDM, non-coding RNAs and extracellular vehicles may be promising biomarkers and even targets for GDM therapies. This review provides an update on our understanding of the role of non-coding RNAs and extracellular vehicles in GDM. As our understanding of the function of lncRNAs and extracellular vehicles improves, the future appears promising for their use as potential biomarkers and treatment targets for GDM in clinical practice.

Upregulation of T Cell Receptor Signaling Pathway Components in Gestational Diabetes Mellitus Patients: Joint Analysis of mRNA and circRNA Expression Profiles

OBJECTIVE

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy, and its pathogenesis is still unclear. Studies have shown that circular RNAs (circRNAs) can regulate blood glucose levels by targeting mRNAs, but the role of circRNAs in GDM is still unknown. Therefore, a joint microarray analysis of circRNAs and their target mRNAs in GDM patients and healthy pregnant women was carried out.

METHODS

In this study, microarray analyses of mRNA and circRNA in 6 GDM patients and 6 healthy controls were conducted to identify the differentially expressed mRNA and circRNA in GDM patients, and some of the discovered mRNAs and circRNAs were further validated in additional 56 samples by quantitative realtime PCR (qRT-PCR) and droplet digital PCR (ddPCR).

RESULTS

Gene ontology and pathway analyses showed that the differentially expressed genes were significantly enriched in T cell immune-related pathways. Cross matching of the differentially expressed mRNAs and circRNAs in the top 10 KEGG pathways identified 4 genes (CBLB, ITPR3, NFKBIA, and ICAM1) and 4 corresponding circRNAs (circ-CBLB, circ-ITPR3, circ-NFKBIA, and circ-ICAM1), and these candidates were subsequently verified in larger samples. These differentially expressed circRNAs and their linear transcript mRNAs were all related to the T cell receptor signaling pathway, and PCR results confirmed the initial microarray results. Moreover, circRNA/miRNA/mRNA interactions and circRNA-binding proteins were predicted, and circ-CBLB, circ-ITPR3, and circ-ICAM1 may serve as GDM-related miRNA sponges and regulate the expression of CBLB, ITPR3, NFKBIA, and ICAM1 in cellular immune pathways.

CONCLUSION

Upregulation of T cell receptor signaling pathway components may represent the major pathological mechanism underlying GDM, thus providing a potential approach for the prevention and treatment of GDM.

Molecular Mechanisms and Functions of lncRNAs in the Inflammatory Reaction of Diabetes Mellitus

Diabetes is a chronic inflammatory state, and several studies have shown that the mechanisms of insulin resistance and abnormal islet β-cell function in diabetes are closely related to inflammatory reactions. Inflammation plays a critical role in diabetic complications. Long noncoding RNAs (lncRNAs), a new area of genomic research for gene regulation, have complex biological functions in various aspects of cellular biological activity. Recent studies have shown that lncRNAs are associated with the regulation of inflammatory responses in various ways, including at the epigenetic, transcriptional, and posttranscriptional levels. This paper presents a brief review of studies on the mechanisms of lncRNAs in diabetic inflammation. The purpose of this article is to determine the role of lncRNAs in the process of diabetic inflammation and to provide new strategies for the use of lncRNAs in the treatments for diabetic inflammation.

Circ_0123996 promotes cell proliferation and fibrosisin mouse mesangial cells through sponging miR-149-5p and inducing Bach1 expression

Diabetic nephropathy (DN) is a serious microvascular complication of diabetes across the world. Recently, many circular RNAs (circRNAs) can exert a crucial role in DN progression. Our investigation was designed to study whether circ_0123996 was associated with DN and aimed to find out the underlying mechanisms. We observed that circ_0123996 expression was significantly increased in Type 2 diabetes (T2D) with DN in comparison to those patients without DN. Consistently, circ_0123996 was also obviously elevated in DN mice models and high glucose (HG)-incubated MMCs. Then, it was proved transfection of circ_0123996 siRNA in mice mesangial cells (MMCs) restrained MMCs proliferation greatly. In addition, it was demonstrated that decrease of circ_0123996 alleviated fibrosis-related protein expression including FN and Col-4 in MMCs. Next, it was confirmed by our study that circ_0123996 can serve as a sponge for miR-149-5p. miR-149-5p has been identified in several diseases including diabetes. At present, we observed that miR-149-5p was decreased in DN. Overexpression of miR-149-5p greatly repressed the effect of circ_0123996 on MMCs. BTB and CNC homology 1 (Bach1) is reported in various disease including some vascular diseases.Here, Bach1 was confirmed as a target of miR-149-5p. Circ_0123996 upregulated Bach1 expression and restrained MMCs proliferation and fibrosis through sponging miR-149-5p. Thus, it was revealed that circ_0123996 was involved in DN via sponging miR-149-5p and modulating Bach1 expression.

Circular RNA microarray expression profile and potential function of circ0005875 in clear cell renal cell carcinoma

Background: Circular RNAs (circRNAs), a novel class of endogenous noncoding RNAs, are involved in a variety of diseases, including several types of cancers. We hypothesized that circRNAs are involved in the tumorigenesis and development of clear cell renal cell carcinoma (ccRCC).

Methods: To verify our hypothesis, we explored the circRNA expression profiles in 4 pairs of ccRCC tissues and their adjacent non-carcinoma tissues via microarray analysis. Selected circRNAs were further validated by qPCR. Moreover, hsa_circ_0005875 was selected for further study and the potential clinical values of hsa_circ_0005875 were investigated in 60 pairs of ccRCC tissues and adjacent normal controls. In addition, the role of hsa_circ_0005875 in ccRCC progression were performed using colony formation assay, Transwell assay and Martrigel-Transwell assay respectively. Finally, interactions between the circRNAs and miRNAs were predicted using Arraystar's miRNA target prediction software. Luciferase reporter assays were performed to evaluate the interaction between hsa_circ_0005875 and hsa_miR-145-5p.

Results: The microarray data showed 1988 circRNAs were significantly dysregulated circRNAs, including 1033 upregulated and 955 downregulated ones in the ccRCC tissues. Hsa_circ_0005875 was confirmed to be significantly upregulated in the ccRCC tumor tissues and renal carcinoma cells. Further analysis revealed that hsa_circ_0005875 expression was associated with tumor size, pathological TNM stage, histological differentiation, and lymphatic metastasis. Functional experiments demonstrated that overexpression of hsa_circ_0005875 increased proliferation, migration and invasion abilities. Moreover, bioinformatics analysis and luciferase reporter assays suggest that hsa_circ_0005875 may serve as a ceRNA (competing endogenous RNA) of miR-145-5p to relieve the repressive effect of miR-145-5p on target ZEB2.

Conclusions: These data indicate that hsa_circ_0005875 might play a role in promoting tumor growth and metastasis and be a potential biomarker of ccRCC.

Quietness of circular RNA circ_0054633 alleviates the inflammation and proliferation in lipopolysaccharides-induced acute lung injury model through NF-κB signaling pathway

AIM

Acute lung injury (ALI) is the mild form of acute respiratory distress syndrome (ARDS) which is a common lung disease with a high incidence and mortality rate. Recent studies manifested that some circular RNAs were associated with ALI. In this study, we aimed to uncover the effect of circular RNA circ_0054633 on ALI initiation and progression and proposed a new mechanism related to ALI.

METHODS

The lipopolysaccharides (LPS)-induced acute lung injury model were build both in vivo of rat and in vitro of primary murine pulmonary microvascular endothelial cells (MPVECs). Hematoxylin and eosin (H&E) was employed to observe the tissue morphology and estimate the degree of lung damage. We used real-time quantitative polymerase chain reaction (RT-qPCR) to measure the expression level of circ_0054633. The expression levels of inflammatory cytokines IL-17A and tumor necrosis factor-α (TNF-α) were detected by ELISA. The effects of circ_0054633 on MPVECs proliferation and apoptosis were detected with the help of CCK-8 and apoptosis assay, separately. The expression level of NF-κB p65 protein was measured by Western blot.

RESULTS

circ_0054633, IL-17A, TNF-α and NF-κB p65 were all overexpressed in LPS-treated rat and MPVECs, and LPS enhanced the proliferation and apoptosis of MPVECs. While circ_0054633 silencing reversed the above promotion effects of LPS on IL-17A, TNF-α expression and MPVECs proliferation and apoptosis.

CONCLUSIONS

Quietness of circ_0054633 alleviated LPS-induced ALI via NF-κB signaling pathway, implicating circ_0054633 may be a potential biomarker for diagnose and therapy of ALI.

Roles of circular RNAs in diabetic complications: From molecular mechanisms to therapeutic potential

Diabetes is characterized by changed homeostasis of blood glucose levels, which is associated with various complications, including cardiomyopathy, atherosclerosis, endothelial dysfunction, nephropathy, retinopathy and neuropathy. In recent years, accumulative evidence has demonstrated that circular RNAs are identified as a novel type of noncoding RNAs (ncRNAs) involving in the regulation of various physiological processes and pathologic conditions. Specifically, the emergence of complications response to diabetes is finely controlled by a complex gene regulatory network in which circular RNAs play a critical role. Recently, circular RNAs are emerging as messengers that could influence cellular functions under diabetic conditions. Dysregulation of circular RNAs has been closely linked to the pathophysiology of diabetes-related complications. In this review, we aimed to summarize the current progression and underlying mechanisms of circular RNA in the development of diabetes-related complications. We will also provide an overview of circular RNA-regulated cell communications in different types of cells that have been linked to diabetic complications. We anticipated that the completion of this review will provide potential clues for developing novel circular RNAs-based biomarkers or therapeutic targets for diabetes and its associated complications.

hsa_circRNA6448-14 promotes carcinogenesis in esophageal squamous cell carcinoma

Circular RNAs (circRNAs) play important roles in cancer progression. hsa_circRNA6448-14 originates from exon 5 to exon 11 of the TGFBI gene. We investigated the roles of hsa_circRNA6448-14 in esophageal squamous cell carcinoma (ESCC) with microarrays and quantitative real-time polymerase chain reaction (qRT-PCR), Kaplan-Meier analysis, loss-of-function and gain-of-function assays, and pull-down assays for miRNA binding. The hsa_circRNA6448-14-miRNA-mRNA network was drawn using Circos. hsa_circRNA6448-14 was significantly upregulated in ESCC tissues and cell lines. As a diagnostic biomarker, hsa_circRNA6448-14 had an area under the curve (AUC), sensitivity, and specificity of 0.906, 82.9%, and 85.5%, respectively. hsa_circRNA6448-14 upregulation was correlated with poor differentiation, advanced pTNM stage, poor disease-free survival (DFS), and poor overall survival (OS). Elevated hsa_circRNA6448-14 promoted cell proliferation, migration, invasion, and inhibited apoptosis in vitro. hsa_circRNA6448-14 functioned as a miRNA sponge to competitively bind miR-455-3p, and hsa_circRNA6448-14 expression negatively correlated with that of miR-455-3p. hsa_circRNA6448-14 promoted carcinogenesis in ESCC, suggesting that hsa_circRNA6448-14 could serve as a diagnostic and prognostic biomarker for ESCC.

Circular RNA hsa_circ_0076690 acts as a prognostic biomarker in osteoporosis and regulates osteogenic differentiation of hBMSCs via sponging miR-152

OBJECTIVE

Osteoporosis is the most common skeletal disease world-wide. The aim of this study is to identify potential circRNA biomarkers for osteoporosis diagnosis and treatment, as well as their roles in regulating osteogenic differentiation.

RESULTS

Hsa_circ_0076690 expression was significantly decreased in osteoporosis patients compared to control and showed an acceptable diagnostic value in clinical samples. Subsequently, hsa_circ_0076690 was identified to act as a sponge of miR-152. The expression of hsa_circ_0076690 was gradually increased during osteogenic differentiation while miR-152 showed a decreased expression trend. Moreover, osteogenic differentiation was promoted by hsa_circ_0076690 over-expression and remain unchanged by miR-152/hsa_circ_0076690 co-overexpression.

CONCLUSIONS

In conclusion, our study revealed that hsa_circ_0076690 may act as a potential diagnostic biomarker for osteoporosis patients and hsa_circ_0076690 could regulate osteogenic differentiation of hBMSCs via sponging miR-152.

MATERIALS AND METHODS

A total of 114 participants were enrolled in this study with ethics approvals. CircRNAs were identified by means of RNA-sequencing and qRT-PCR experiment. The clinical significance was measured by ROC curve analysis. Target relationship was validated by luciferase reporter assay. The osteogenic-associated biomarkers and ALP activity were detected by western blots.