Circular RNA (circRNA) is a kind of novel endogenous noncoding RNA formed through back-splicing of mRNA precursor. The biogenesis, degradation, nucleus–cytoplasm transport, location, and even translation of circRNA are controlled by RNA-binding proteins (RBPs). Therefore, circRNAs and the chaperoned RBPs play critical roles in biological functions that significantly contribute to normal animal development and disease. In this review, we systematically characterize the possible molecular mechanism of circRNA–protein interactions, summarize the latest research on circRNA–protein interactions in muscle development and myocardial disease, and discuss the future application of circRNA in treating muscle diseases. Finally, we provide several valid prediction methods and experimental verification approaches. Our review reveals the significance of circRNAs and their protein chaperones and provides a reference for further study in this field.

MiRNAs are well known to be gene repressors. A newly identified class of miRNAs termed nuclear activating miRNAs (NamiRNAs), transcribed from miRNA loci that exhibit enhancer features, promote gene expression via binding to the promoter and enhancer marker regions of the target genes. Meanwhile, activated enhancers produce endogenous non-coding RNAs (named enhancer RNAs, eRNAs) to activate gene expression. During chromatin looping, transcribed eRNAs interact with NamiRNAs through enhancer-promoter interaction to perform similar functions. Here, we review the functional differences and similarities between eRNAs and NamiRNAs in myogenesis and disease. We also propose models demonstrating their mutual mechanism and function. We conclude that eRNAs are active molecules, transcriptional regulators, and partners of NamiRNAs, rather than mere RNAs produced during enhancer activation.

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.

Muscle growth and injury-induced regeneration are controlled by skeletal muscle satellite cells (MuSCs) through myogenesis in postnatal animals. Meanwhile, myogenesis is accompanied by mitochondrial function and enzyme activity. Nevertheless, the underlying molecular mechanisms involving non-coding RNAs including circular RNAs (circRNAs) and microRNAs (miRNAs) remain largely unsolved. Here, we explored the myogenic roles of miR-145-3p and MYBL1 on muscle development and mitochondrial mass. We noticed that overexpression of miR-145-3p inhibited MuSCs proliferation and reduced the number of viable cells. Meanwhile, deficiency of miR-145-3p caused by LNAantimiR-145-3p or an inhibitor retarded the differentiation of MuSCs. miR-145-3p altered the mitochondrial mass in MuSCs. Moreover, miR-145-3p targeted and negatively regulated the expression of CDR1as and MYBL1. The knockdown of the MYBL1 using ASO-2′MOE modification simulated the inhibitory function of miR-145-3p on cell proliferation. Additionally, MYBL1 mediated the regulation of miR-145-3p on Vexin, VCPIP1, COX1, COX2, and Pax7. These imply that CDR1as/miR-145-3p/MYBL1/COX1, COX2, VCPIP1/Vexin expression at least partly results in a reduction in mitochondrial mass and MuSCs proliferation. These novel findings confirm the importance of mitochondrial mass during myogenesis and the boosting of muscle/meat development in mammals.

Norrin-induced activation of β-catenin–dependent signaling through the receptor frizzled4 in endothelial cells (ECs) is essential for establishing and maintaining blood-CNS barrier function. We sought to determine how this pathway is modulated under stress or disease conditions. Specifically, we investigated the role of p53 in endothelial blood-CNS barriers because increased abundance of the transcription factor p53 in ECs correlates with leaky CNS blood vessels in type 2 diabetes. Using transcriptomic, cell-based, and mouse genetic approaches, we identified interplay between p53 and its negative regulator MDM2 and norrin/frizzled4 signaling. Mice with an EC-specific ablation of Mdm2 showed decreased norrin/frizzled4 signaling, reduced EC proliferation and retinal angiogenesis, and disrupted blood-retina barrier function, all of which were largely restored by concurrent Trp53 deletion. Decreased norrin/frizzled4 signaling and inhibition of EC proliferation in response to p53 were associated with reduced expression of the condensin I complex component non-SMC condensin I complex subunit H (NCAPH). This study identifies a regulator of norrin/frizzled4 signaling and suggests that the clinical use of MDM2 inhibitors might impair the blood-CNS barrier. In addition, NCAPH may be a downstream effector of p53 in ECs and a candidate gene for familial exudative vitreoretinopathy (FEVR), which is caused by defects in norrin signaling.

Text classification technology has been efficiently deployed in numerous organizational applications, including subject tagging, intent, event detection, spam filtering, and email routing. This also helps organizations streamline processes, enhance data-driven operations, and evaluate and analyze textual resources quickly and economically. This progress results from numerous studies on high-resource language-based text classification tasks. However, research in low-resource languages, including Ewe, Arabic, Filipino, and Kazakh, lags behind other high-resource languages like English. Also, the most difficult aspect of text classification using low-resource languages is identifying the optimal set of filters for its feature extraction. This is due to their complex morphology, linguistic diversity, multilingualism, and syntax. Studies that have explored these problems failed to efficiently use label information to better the performance of their methods. As a result, the label information for these languages needs to be adequately utilized to enhance classification results. To solve this problem, this study proposes an efficient adaptive convolutional model based on label embedding (EAdaCLE) to efficiently represent label information and utilize the learned label representations for various text classification tasks. EAdaCLE has adaptively engineered convolutional filters trained on inputs based on label embeddings generated in the same network as the text vectors. EAdaCLE ensures the adaptability of adaptive convolution and completely obtains label data as a supporting function to enhance the classification results. Extensive experiments indicate that our technique is more reliable than other methods on four low-resource public datasets.