Cerebellar Degeneration-related Protein Research Articles

CircRNA CDR1as affects functional repair after spinal cord injury and regulates fibrosis through the SMAD pathway

Spinal cord injury (SCI) is a complex problem in modern medicine. Fibroblast activation and fibroscarring after SCI impede nerve recovery. Non-coding RNA plays an important role in the progression of many diseases, but the study of its role in the progression of spinal fibrosis is still emerging. Here, we investigated the function of circular RNAs, specifically antisense to the cerebellar degeneration-related protein 1 (CDR1as), in spinal fibrosis and characterized its molecular mechanism and pathophysiology. The presence of CDR1as in the spinal cord was verified by sequencing and RNA expression assays. The effects of inhibition of CDR1as on scar formation, inflammation and nerve regeneration after spinal cord injury were investigated in vivo and in vitro. Further, gene expression of miR-7a-5p and protein expression of transforming Growth Factor Beta Receptor II (TGF-βR2) were measured to evaluate their predicted interactions with CDR1as. The regulatory effects and activation pathways were subsequently verified by miR-7a-5p inhibitor and siCDR1as. These results indicate that CDR1as/miR-7a-5p/TGF-βR2 interactions may exert scars and nerves functions and suggest potential therapeutic targets for treating spinal fibrotic diseases.

GDF11 mitigates high glucose-induced cardiomyocytes apoptosis by inhibiting the ALKBH5-FOXO3-CDR1as/Hippo signaling pathway

Diabetic cardiomyopathy remains a formidable health challenge with a high mortality rate and no targeted treatments. Growth differentiation factor 11 (GDF11) has shown promising effects on cardiovascular diseases; however, its role and the underlying mechanism in regulating diabetic cardiomyopathy remain unclear. In this study, we developed mouse models of diabetic cardiomyopathy using leptin receptor-deficient (db/db) mice and streptozocin-induced C57BL/6 mice. The diabetic cardiomyopathy model mice exhibited apparent structural damage in cardiac tissues and a significant increase in the expression of apoptosis-related proteins. Notably, we observed a significant decreased expression of GDF11 in the myocardium of mice with diabetic cardiomyopathy. Moreover, GDF11 cardiac-specific knock-in mice (transgenic mice) exhibited improved cardiac function and reduced apoptosis. Moreover, exogenous administration of GDF11 mitigated high glucose-induced cardiomyocyte apoptosis. Mechanistically, we demonstrated that GDF11 alleviated high glucose-induced cardiomyocytes apoptosis by inhibiting the activation of the alkylation repair homolog 5 (ALKBH5)-forkhead box group O3a (FOXO3)-cerebellar degeneration-related protein 1 transcript (CDR1as)/Hippo signaling pathway. Consequently, this novel mechanism effectively counteracted myocardial cell apoptosis, providing valuable insights into potential therapeutic strategies for clinical diabetic cardiomyopathy.

CDR2 and CDR2L line blot performance in PCA-1/anti-Yo paraneoplastic autoimmunity.

Purkinje cytoplasmic autoantibody type 1 (PCA-1)/anti-Yo autoimmunity is a common high-risk paraneoplastic neurological disorder, traditionally attributed antigenically to cerebellar degeneration-related protein 2 (CDR2), predominantly affecting women with gynecologic or breast adenocarcinoma. Single-modality CDR2 testing may produce false-positive results. We assessed the performance characteristics of the more recently purported major PCA-1/Yo antigen, CDR2-like (CDR2L), side by side with CDR2, in a line blot format. CDR2 and CDR2L were tested in six specimen groups (serum and cerebrospinal fluid (CSF)). Group 1, PCA-1/Yo mouse brain indirect immunofluorescence assay (IFA) positives; Group 2, PCA-1/Yo IFA mimics; Group 3, suspected CDR2 line blot false positives; Group 4, consecutive patient samples tested for neural antibodies over 1 year; Group 5, healthy subject serums; and Group 6, polyclonal (non-specific) immunoglobulin G (IgG)-positive serums. Group 1: Of 64 samples tested, all but two were CDR2 positive (both CSF samples) and all were CDR2L positive. In individual patients, CDR2L values were always higher than CDR2. The two "CDR2L-only" positives were CSF samples with low titer PCA-1/Yo by IFA with serum negativity but with typical clinical phenotype. Group 2: All 51 PCA-1/Yo mimics were CDR2/CDR2L negative. Group 3: Nine samples [six of 1289 (0.47%) serums and three of 700 CSF samples (0.43%) were PCA-1/Yo IFA negative/CDR2 positive; two of the six available (serums from the same patient) were also CDR2L positive; the other four CDR2L negative had low CDR2 values (17-22). Group 4: Twenty-two patients had unexpected CDR2 or CDR2L positivity; none had tissue IFA positivity. Eleven of the 2,132 serum (0.5%) and three of the 677 CSF (0.4%) samples were CDR2 positive; median value was 19 (range, 11-48). Seven of the 2,132 serum (0.3%) and three of the 677 CSF (0.4%) samples were CDR2L positive; median value was 18 (range, 11-96). Group 5: All 151 healthy serum samples were negative. Group 6: One of the 46 polyclonal serum samples was CDR2L positive. Optimum overall performance was accomplished by requiring both CDR2 and CDR2L positivity in serum (sensitivity, 100%; and specificity, 99.9%) and positivity for CDR2L in CSF (sensitivity, 100%; and specificity, 99.6%). CDR2L provides additional PCA-1/anti-Yo sensitivity in CSF, and dual positivity with CDR2 provides additional specificity assurance in serum. Combining antigen-specific and tissue-based assays optimizes PCA-1/anti-Yo testing.

B-111 Parallel Detection of Antibodies against CDR2L and CDR2 Increases the Diagnostic Specificity in Serological Diagnostics of Paraneoplastic Cerebellar Degeneration

Abstract Background Onconeuronal anti-Yo antibodies are key diagnostic markers for paraneoplastic cerebellar degeneration (PCD) and often associated with gynaecologic/breast cancer. Cerebellar degeneration-related protein 2-like (CDR2L), but not cerebellar degeneration-related protein 2 (CDR2), has recently been shown to be the major anti-Yo target (1, 2). This study investigated if inclusion of CDR2L in diagnostic tests results in increased specificity for PCD. Methods Three panels were examined for reactivity against CDR2L and CDR2 by line blot analysis (EUROLINE). Panel A comprised 14 preselected sera from women with Yo-specific reactivity by indirect immunofluorescence assay (IFA) on rat cerebellum, presenting with cerebellar ataxia (n = 13) or peripheral neuropathy (n = 1) and underlying gynaecologic/breast cancers (n = 14). Panel B included 2132 non-selected consecutive serum/CSF samples from patients with neurological symptoms. Panel C consisted of 150 samples from healthy blood donors. Results In Panel A, all samples (100%) from patients with typical clinical characteristics for Yo-associated PCD showed strong positive reactivity to both CDR2L and CDR2. In Panel B, seven (0.3%) sera were anti-CDR2 negative, but anti-CDR2L positive, all of them from patients (6M/1F) without PCD and two with cancer or pre-cancerous condition. Eleven (0.5%) patients (9M/2F) were found to be anti-CDR2 positive, but anti-CDR2L negative, including two with cerebellar ataxia and three with cancer or pre-cancerous condition. In all 18 cases, IFA on rat cerebellum was negative, suggesting non-specific line blot reactivity to CDR2L or CDR2. In Panel C, 0/150 sera were anti-CDR2L and 1/150 anti-CDR2 positive, corresponding to specificities of 100% and 99.3%, respectively. The anti-CDR2 positive blood donor was male with negative IFA result. Conclusion Using CDR2L in addition to CDR2 increases the specificity in diagnosing anti-Yo-associated PCD. Positive line blot reactivity against both parameters seems to confirm the diagnosis. In contrast, results showing isolated reactivity against either CDR2L or CDR2 have to be interpreted carefully as they may apply to non-PCD cases.

Localised Cdr1as activity is required for fear extinction memory

Circular RNAs (circRNAs) comprise a novel class of regulatory RNAs that are abundant in the brain, particularly within synapses. They are highly stable, dynamically regulated, and display a range of functions, including serving as decoys for microRNAs and proteins and, in some cases, circRNAs also undergo translation. Early work in animal models revealed an association between circRNAs and neurodegenerative and neuropsychiatric disorders; however, little is known about the link between circRNA function and memory. To address this, we examined circRNA in synaptosomes derived from the medial prefrontal cortex of fear extinction-trained male C57BL/6J mice and found 12,837 circRNAs that were enriched at the synapse, including cerebellar degeneration-related protein 1 antisense RNA (Cdr1as). Targeted knockdown of Cdr1as in the neural processes of the infralimbic cortex led to impaired fear extinction memory. These findings highlight the involvement of localised circRNA activity at the synapse in memory formation.

A cerebellar degeneration-related protein 2-like cell-based assay for anti-Yo detection in patients with paraneoplastic cerebellar degeneration.

Commercially available tests for Yo antibody detection have low specificity for paraneoplastic cerebellar degeneration (PCD) because these assays use cerebellar degeneration-related protein 2 (CDR2) as the antigen, not CDR2-like (CDR2L). We aimed to test the hypothesis that use of a CDR2L cell-based assay (CBA), as an additional screening technique, would increase the accuracy of Yo-PCD diagnosis. An in-house CBA to test for anti-CDR2L antibodies was developed and used to screen sera from 48 patients with confirmed anti-Yo-associated PCD. Fifteen non-Yo PCD patients, 22 patients with ovarian cancer without neurological syndromes, 50 healthy blood donors, 10 multiple sclerosis, 15 Parkinson's disease, and five non-paraneoplastic ataxic patients were included as controls. Sera were also tested by western blot analysis using recombinant CDR2 and CDR2L proteins developed in house, by the commercially available line immunoassays from Ravo Diagnostika and Euroimmun, and by the CDR2 CBA from Euroimmun. The CDR2L CBA identified all 48 patients with Yo-PCD. No CDR2L CBA reaction was observed in any of the control sera. The western blot technique had lower sensitivity and specificity as sera from eight and six of the 48 Yo-PCD patients did not react with recombinant CDR2 or CDR2L, respectively. The CDR2L CBA is highly reliable for identification of Yo-PCD. Although our findings indicate that, currently, the combination of CDR2 and CDR2L yields the most reliable test results, it remains to be evaluated if a test for single anti-CDR2L positivity will serve as a sufficient biomarker for Yo-PCD diagnosis.

Circular RNA Cerebellar Degeneration-Related Protein 1 Antisense RNA (Circ-CDR1as) Relative Expression Levels Are Independent Contributors to Insulin Resistance Induced Peripheral Neuropathy

Circular RNA Cerebellar Degeneration-Related Protein 1 Antisense RNA (Circ-CDR1as) Relative Expression Levels Are Independent Contributors to Insulin Resistance Induced Peripheral Neuropathy

Paraneoplastic cerebellar degeneration with anti-Yo antibodies and an associated submandibular gland tumor: a case report

BackgroundAs a debilitating syndrome, paraneoplastic cerebellar degeneration (PCD) remains challenging to treat. Further, anti-Yo antibody (directed against human cerebellar degeneration-related protein 2) detection in patients with PCD is associated with unsatisfactory responses to existing therapies. Here, we present the case of a 60-year-old woman who developed PCD with anti-Yo antibodies and a submandibular gland tumor.Case presentationA 60-year-old woman presented with a 5-day history of unsteadiness of gait and inadequate coordination of her extremities, along with truncal instability. Although walking without aid was possible, dysmetria of all four limbs, trunk, and gait ataxia was observed. While routine biochemical and hematological examinations were normal, the patient’s blood was positive for anti-Yo antibodies. When the neurological symptoms deteriorated despite administration of intravenous methylprednisolone, fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) images with contrast enhancement were performed, which showed a tumor in the left submaxillary gland. She underwent total left submandibular gland resection, including the tumor; histological and immunohistochemical results revealed a salivary duct carcinoma. She was administered intravenous methylprednisolone, followed by 10 plasma exchange sessions, intravenous immunoglobulins, and cyclophosphamide therapy. Following treatment, her symptoms were not alleviated, even after the reduction of anti-Yo titers.ConclusionsAlthough tumor detection was delayed, early tumor detection, diagnosis, and PCD treatment are essential because any delay can result in the progression of the disorder and irreversible neurological damage. Therefore, we recommend that the possibility of a salivary gland tumor should be considered, and whole-body dual-modality CT, including the head and neck, and FDG-PET should be performed at the earliest for patients with well-characterized paraneoplastic antibodies when conventional imaging fails to identify a tumor.

Knockdown of CDR1as Decreases Differentiation of Goat Skeletal Muscle Satellite Cells via Upregulating miR-27a-3p to Inhibit ANGPT1.

Myogenesis is a complex process controlled by several coding and non-coding RNAs (ncRNAs), such as circular RNAs (circRNAs) that are known to function as endogenous microRNAs (miRNAs) sponges. Cerebellar Degeneration-Related protein 1 antisense (CDR1as) is the most spotlighted circRNA that is known as an miR-7 sponge, which has bloomed circRNAs’ research in animal disease and physiology. Here, we screened for miRNAs and mRNA associated with CDR1as and further characterized their regulatory function during muscle differentiation. We found that a total of 43 miRNAs (including miR-107-3p, miR-125b-5p, miR-140-5p, miR-29a-3p, and miR-27a-3p upregulated) and 789 mRNAs (including ANGPT1, E2F2, CCN1, FGFR1, and MEF2C downregulated) were differentially expressed in goat skeletal muscle satellite cells (SMSCs). Further, knockdown of CDR1as and ANGPT1 inhibited SMSCs differentiation. miR-27a-3p was differentially upregulated after the knockdown of CDR1as in SMSCs. Overexpressed miR-27a-3p decreased SMSCs differentiation. Via RNAhybrid and luciferase, miR-27a-3p was identified to regulate ANGPT1. We discovered that miR-27a-3p has an inverse relationship with CDR1as and decreases the expression level of ANGPT1 during SMSCs differentiation. In summary, our study demonstrates that siCDR1as inhibits myoblast differentiation by downregulating ANGPT1 mRNA via miR-27a-3p in SMSCs.

CircRNA CDR1as promotes cardiomyocyte apoptosis through activating hippo signaling pathway in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM), as a major complication of diabetic patients, can cause myocardial metabolic remodeling and lead to severe and irreversible cardiac dysfunction. Previously, we found that the circular RNA cerebellar degeneration-related protein 1 antisense (Circ-CDR1as) independently predicted acute myocardial infarction (AMI) and might be a new indicator marker for this. However, CDR1as was not clearly described in diabetic cardiomyopathy. Therefore, our purpose was to deeply explore the function of CDR1as in DCM. In this study, we found that CDR1as was upregulated in DCM, and knockdown of CDR1as could improve the apoptosis caused by DCM. Mechanistically, CDR1as activates the Hippo signaling pathway by significantly inhibiting Mammalian sterile 20-like kinase 1 (MST1) ubiquitination level. Furthermore, as a transcriptional factor of CDR1as, Forkhead box group O3a (FOXO3) was identified to activate the Hippo signaling pathway. Notably, the total m6A level was downregulated in the cardiac tissue of DCM. Alk B homolog 5 (ALKBH5), a m6A demethylation enzyme, was upregulated in the cardiomyocytes of DCM mice and posttranscriptionally activated FOXO3 by m6A demethylation in an m6A-YTHDF2-dependent manner. Hence, our work reveals the key function of the ALKBH5-FOXO3-CDR1as/Hippo signaling pathway in DCM and provides insight into the critical roles of m6A methylation in DCM.

Circular RNA cerebellar degeneration-related protein 1 antisense RNA (Circ-CDR1as) downregulation induced by dexmedetomidine treatment protects hippocampal neurons against hypoxia/reoxygenation injury through the microRNA-28-3p (miR-28-3p)/tumor necrosis factor receptor-associated factor-3 (TRAF3) axis

ABSTRACT Cerebral ischemia/reperfusion (CI/R) injury results in serious brain tissue damage, thereby leading to long-term disability and mortality. It has been reported that dexmedetomidine (DEX) exerted neuroprotective effects in CI/R injury. Herein, we intended to investigate whether and how circular RNA (circRNA) cerebellar degeneration-related protein 1 antisense RNA (circ-CDR1as) was involved in the DEX-mediated protection on hippocampal neurons. In our work, the mouse hippocampal neuronal cells (HT-22) were used to construct a hypoxia/reperfusion (H/R) model for CI/R injury. Cell proliferation and apoptosis were evaluated by CCK-8 and flow cytometry. Gene expressions were detected by RT-qPCR. Levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) were measured by ELISA. The association between miR-28-3p and circ-CDR1as or TRAF3 was verified by dual-luciferase assay. The results indicated that DEX alleviated HT-22 cell dysfunction induced by H/R treatment. In addition, circ-CDR1as was downregulated after DEX treatment and reversed the effects of DEX on the proliferation, apoptosis, and inflammatory responses of H/R-treated HT-22 cells. Circ-CDR1as positively regulated TRAF3 expression via interaction with miR-28-3p in HT-22 cells. Circ-CDR1as aggravated H/R-treated HT-22 cell dysfunction through targeting miR-28-3p. Furthermore, TRAF3 inhibition partly abolished the effect of circ-CDR1as overexpression on cellular activities of H/R-treated HT-22 cells. To sum up, our findings, for the first time, demonstrated that DEX exerted neuroprotective effects on hippocampal neurons against H/R treatment via the circ-CDR1as/miR-28-3p/TRAF3 regulatory network, providing novel therapeutic targets for DEX administration in CI/R treatment.

Effect of the circCDR1as/miR-641/XIAP regulatory axis on the proliferation and invasion of the prostate cancer PC-3 cell line.

Prostate cancer is one of the most common malignant tumors in men. Patients with local infiltration and distant metastasis often have a poor prognosis. The present study aimed to investigate the expression and regulatory mechanism of the circular RNA cerebellar degeneration-related protein 1, anti-sense (circCDR1as) in prostate cancer cell lines. MicroRNAs (miRNAs) regulated by circCDR1as and target genes regulated by miRNAs were predicted using bioinformatics software. Prostate cancer cell lines (LNCaP, 22Rv1 and PC-3), a normal prostate epithelial cell line (RWPE-1) and a human embryonic kidney cell line (293T) were cultured. Relative gene expression was detected using reverse transcription PCR. Small interfering RNAs (siRNAs) targeting circCDR1as and X-linked inhibitor of apoptosis protein (XIAP) and miRNA mimics were designed and transfected into the cell lines using Lipofectamine® 3000. Cell invasion was determined using a Transwell assay, the cell proliferation rate was detected using an MTT assay and cell migration was examined using a scratch assay. Relative protein expression was detected using western blotting. Double fluorescent reporter gene vectors and an anti-Ago2 RNA-binding protein immunoprecipitation assay were used to verify binding. Bioinformatics analyses indicated that there was a binding site between miR-641 and circCDR1as and between miR-641 and XIAP. The expression of circCDR1as and XIAP was higher and the expression of miR-641 was lower in the prostate cancer cell lines compared with the normal prostate epithelial cell line. After effectively reducing the expression of circCDR1as and XIAP and increasing the expression of miR-641 in PC-3 cells, the proliferation, invasion and migration of PC-3 cells were effectively inhibited. circCDR1as could bind to miR-641, which targeted the 3′-untranslated region of XIAP. Reducing the expression of circCDR1 promoted the expression of miR-641 and inhibited the expression of XIAP. Overall, the circCDR1as/miR-641/XIAP regulatory axis plays a role in the invasion and migration of the prostate cancer PC-3 cell line.

UVB-Induced ciRS-7 Activates Melanogenesis by Paracrine Effects.

Antisense to the cerebellar degeneration-related protein 1 transcript (CDR1as or ciRS-7) is an important member of the circular RNA family and is involved in the regulation of numerous biological functions. Keratinocytes and fibroblasts (FBs) affect melanogenesis through paracrine effects. However, whether ciRS-7 is involved in melanogenesis by regulating paracrine effects remains unclear. This study demonstrates for the first time that ciRS-7 is highly expressed in keratinocytes, FBs, and melanocytes (MCs). Ultraviolet B (UVB) irradiation promotes ciRS-7 expression in keratinocytes and FBs. Following inhibition of ciRS-7 expression in keratinocytes and FBs, the culture supernatant from these cells inhibited melanogenesis of MCs. Further analyses revealed that the expression and secretion of fibroblast growth factor 2 (FGF2) and phosphorylation of STAT3 and AKT in keratinocytes and FBs were significantly downregulated following inhibition of ciRS-7 expression, whereas the level of miR-7 was increased. Overexpression of miR-7 in keratinocytes and FBs significantly inhibited the expression of FGF2. In conclusion, our findings demonstrate that UVB-induced ciRS-7 triggers melanogenesis in MCs through regulation of the miR-7/STAT3 and AKT/FGF2 paracrine axis in both keratinocytes and FBs. ciRS-7 may serve as a regulator in the development of pigmented skin diseases.

Paraneoplastic Cerebellar Degeneration: The Importance of Including CDR2L as a Diagnostic Marker.

ObjectiveInvestigate the value of including cerebellar degeneration-related protein 2-like (CDR2L) as a marker in commercial diagnostic tests for anti-Yo–associated paraneoplastic cerebellar degeneration (PCD).MethodsWe included sera and CSF samples from 24 patients with suspected PCD (6 of whom had PCD with underlying gynecologic or breast cancer), who were positive for Yo antibodies using the commercially available, paraneoplastic neurologic syndromes (PNS) 14 Line Assay from Ravo Diagnostika. The samples were further evaluated using the EUROLINE PNS 12 Ag Line Assay and a cell-based assay (CBA) from Euroimmun. For confirmation of positive lineblot results, we used indirect immunofluorescence of rat cerebellar sections. We also tested all samples in 2 assays developed in-house: a CBA for CDR2L and a Western blot analysis using recombinant cerebellar degeneration-related protein 2 (CDR2) and CDR2L proteins.ResultsIn PNS 14 and PNS 12 Ag Line Assays, anti-CDR2 reactivity was observed for 24 (100%) and 20 (83%) of the 24 samples, respectively. Thirteen of 24 subjects (54%) were also positive using the Euroimmun CBA. Rat cerebellar immunofluorescence was the best confirmatory test. In our in-house CBA for CDR2L and Western blot for CDR2 and CDR2L, only the 6 patients with confirmed PCD reacted with CDR2L.ConclusionsCommercially available tests for Yo antibody detection have low specificity for PCD because these assays use CDR2 as antigen. By adding a test for CDR2L, which is the major Yo antigen, the accuracy of PCD diagnosis greatly improved.Classification of EvidenceThis study provides Class III evidence that a CBA for CDR2L accurately identifies patients with PCD.

Circular RNA CDR1as-induced autophagy regulates the proliferation and migration of CD44+/CD24- phenotype breast cancer stem cells in vitro

Competitive endogenous RNA (ceRNA) plays a vital role in cancer stem cells. In the present study, we aimed to investigate the role of the circular RNA (circRNA) antisense to the cerebellar degeneration-related protein 1 transcript (CDR1as) during competitive inhibition of microRNA-7 (miR-7) in the regulation of autophagy to modulate the proliferation and migration of breast cancer stem cells. The CD44+/CD24- phenotype breast cancer stem cells were sorted from the original MCF7 cell by flow cytometry. RT-qPCR was applied to assess the expression of CDR1as and miR-7 in MCF7-Parent and MCF7-Stem cells. The activity of autophagy was evaluated followed the knockdown and overexpression of CDR1as. The correlation between CDR1as and miR-7 and between CDR1as and miR-7-target mRNAs were evaluated. This study revealed that CDR1as overexpression was associated with up-regulation of autophagy and that CDR1as competitive inhibition of miR-7 enhanced the LKB1-AMPK-mTOR signaling and autophagy-associated genes in breast cancer stem cells. CDR1as promoted the cell growth and migration of breast CSCs via the CDR1as/miR-7 axis, and knockdown of CDR1as and miR-7 overexpression obviously impaired the ability of growth and migration. The present study added a new view of developing a new therapeutic strategy against breast cancer.

The Emerging Picture of the Roles of CircRNA-CDR1as in Cancer.

Circular RNAs (circRNAs) are covalently closed circular structures without 5′ caps and 3′ tails, which are mainly formed from precursor mRNAs (pre-mRNAs) via back-splicing of exons. With the development of RNA sequencing and bioinformatic analysis, circRNAs were recently rediscovered and found to be widely expressed in the tree of life. Cerebellar degeneration-related protein 1 antisense RNA (CDR1as) is recognized as one of the most well-identified circRNAs. It contains over 70 miR-7 binding sites and can regulate gene activity by sponging miR-7. Increasing numbers of studies have recently demonstrated that CDR1as is abnormally expressed in many types of tumors, such as colorectal cancer, cholangiocarcinoma and osteosarcoma, and plays a vital role in the development of cancer. However, there are few reviews focusing on CDR1as and cancer. Hence, it is important to review and discuss the role of CDR1as in cancer. Here, we first review the main biological features of CDR1as. We then focus on the expression and roles of CDR1as in cancer. Finally, we summarize what is known on the role of CDR1as in cancer and discuss future prospects in this area of research.

Revealing Epigenetic Factors of circRNA Expression by Machine Learning in Various Cellular Contexts.

SummaryCircular RNAs (circRNAs) have been identified as naturally occurring RNAs that are highly represented in the eukaryotic transcriptome. Although a large number of circRNAs have been reported, the underlying regulatory mechanism of circRNAs biogenesis remains largely unknown. Here, we integrated in-depth multi-omics data including epigenome, transcriptome, and non-coding RNA and identified candidate circRNAs in six cellular contexts. Next, circRNAs were divided into two classes (high versus low) with different expression levels. Machine learning models were constructed that predicted circRNA expression levels based on 11 different histone modifications and host gene expression. We found that the models achieve great accuracy in predicting high versus low expressed circRNAs. Furthermore, the expression levels of host genes of circRNAs, H3k36me3, H3k79me2, and H4k20me1 contributed greatly to the classification models in six cellular contexts. In summary, all these results suggest that epigenetic modifications, particularly histone modifications, can effectively predict expression levels of circRNAs.

A Circle RNA Regulatory Axis Promotes Lung Squamous Metastasis via CDR1-Mediated Regulation of Golgi Trafficking.

Lung squamous carcinoma (LUSC) is a highly metastatic disease with a poor prognosis. Using an integrated screening approach, we found that miR-671-5p reduces LUSC metastasis by inhibiting a circular RNA (circRNA), CDR1as. Although the putative function of circRNA is through miRNA sponging, we found that miR-671-5p more potently silenced an axis of CDR1as and its antisense transcript, cerebellar degeneration related protein 1 (CDR1). Silencing of CDR1as or CDR1 significantly inhibited LUSC metastases and CDR1 was sufficient to promote migration and metastases. CDR1, which directly interacted with adaptor protein 1 (AP1) complex subunits and coatomer protein I (COPI) proteins, no longer promoted migration upon blockade of Golgi trafficking. Therapeutic inhibition of the CDR1as/CDR1 axis with miR-671-5p mimics reduced metastasis in vivo. This report demonstrates a novel role for CDR1 in promoting metastasis and Golgi trafficking. These findings reveal an miRNA/circRNA axis that regulates LUSC metastases through a previously unstudied protein, CDR1. SIGNIFICANCE: This study shows that circRNA, CDR1as, promotes lung squamous migration, metastasis, and Golgi trafficking through its complimentary transcript, CDR1.

Exendin-4 Reversed the PC12 Cell Damage Induced by circRNA CDR1as/miR-671/GSK3β Signaling Pathway.

The purpose of this paper is to study the effect of circRNA cerebellar degeneration-related protein 1 antisense RNA(CDR1as)/miR-671/GSK3β signaling pathway on PC12 cell injury and the mechanism of Exendin-4 (Ex-4) in PC12 cell injury protection. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was used to detect the expression levels of circular RNA CDR1as and miR-671 in PC12 cells. By overexpressing or knocking out CDR1as, miR-671, and GSK3β, the role of CDR1as, miR-671, and GSK3β in PC12 cell injury was analyzed. The binding of CDR1as to miR-671 and GSK3β to miR-671 was verified by dual luciferase reporter assay. PC12 cells were treated with 1-methyl-4 phenyl-pyridine ion (MPP+) to construct a PC12 cell damage model. PC12 cell transfection experiments were used to confirm the role of CDR1as/miR-671/GSK3β signal axis in PC12 cell damage, and the role of Ex-4 in the association of circRNA CDR1as/miR-671/GSK3β signaling axis and PC12 cell damage. PC12 cell damage was detected by 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cellular lactate dehydrogenase (LDH) release. Ex-4 reversed the phosphorylation levels of PI3K, AKT, and GSK-3β in MPP+-treated PC12 cells, and reduced MPP+-induced PC12 cell damage. CircRNA CDR1as upregulated the expression of GSK3β by sponge miR-671. Ex-4 downregulated CDR1as expression and upregulated miR-671 expression in MPP+-induced PC12 cell. Silencing of CDR1as reduced MPP+-induced PC12 cell damage. CDR1as transfection downregulated the expression of miR-671 in PC12 cells, promoted the expression and phosphorylated of GSK3β, and induced PC12 cell damage. GSK3β silencing reversed CDR1as-induced PC12 cell damage. CDR1as promoted the phosphorylation level of GSK3β in PC12 cells to cause cell damage; Ex-4 reversed the phosphorylation of GSK3β caused by CDR1as in PC12 cells and reduced the PC12 cell damage caused by CDR1as. Ex-4 reverses the damage of PC12 cells induced by CDR1as/miR-671/GSK3β signaling pathway.

CDR1as/miR-7/CKAP4 axis contributes to the pathogenesis of abdominal aortic aneurysm by regulating the proliferation and apoptosis of primary vascular smooth muscle cells.

Abdominal aortic aneurysm (AAA) is characterized as dilation of the aortic wall. Dysregulation of vascular smooth muscle cells (VSMCs) can contribute to the development of this phenotype. Circular RNAs and microRNAs (miRNAs) can regulate the proliferation and apoptosis of VSMCs. This present study aimed to identify the mechanisms of action behind the regulation of cerebellar degeneration-related protein 1 antisense RNA (CDR1as)/miRNA (miR)-7 in VSMCs. The expression levels of miR-7 were upregulated, whereas the levels of CDR1as and cytoskeleton-associated protein 4 (CKAP4) were downregulated in aortic specimens obtained from 10 patients who underwent surgery for AAA compared with aortic specimens from 10 control patients who underwent coronary artery bypass surgery. The molecular mechanism of action of CDR1as/miR-7 was investigated in primary VSMCs. The results of Cell Counting kit-8 and cell growth curve assays revealed that overexpression of CDR1as and knockdown of miR-7, increased VSMC proliferation, whereas knockdown of CDR1as and overexpression of miR-7 suppressed VSMC proliferation. In addition, overexpression of CDR1as and knockdown of miR-7, suppressed apoptosis in VSMCs, indicated by the decreased levels of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) activity, whereas knockdown of CDR1as and overexpression of miR-7 exhibited the opposite effects. The results of luciferase reporter and biotin pull-down assays confirmed that CDR1as directly bound to miR-7 and suppressed its expression. Additionally, the CDR1as-induced proliferation and suppressed apoptosis was reversed by the overexpression of miR-7. Furthermore, luciferase reporter, reverse transcription-quantitative PCR and western blot assays revealed that miR-7 directly targeted CKAP4 and suppressed its expression. Additionally, the miR-7-suppressed proliferation and increased ROS and LDH activity were reversed by the overexpression of CKAP4. CDR1as also decreased caspase 3/7 activity, which was reversed by miR-7 mimics. miR-7 increased the activity of caspase 3/7, which was again reversed by the overexpression of CKAP4. Therefore, CDR1as, miR-7 and CKAP4 may act in the same pathway to regulate VSMC proliferation and apoptosis.