Circ-Ctnnb1 regulates neuronal injury in spinal cord injury through Wnt/β-catenin signaling pathway

YY1/circCTNNB1/miR-186-5p/YY1 positive loop aggravates lung cancer progression through the Wnt pathway

Lung cancer is one familiar cancer that threatens the lives of humans. circCTNNB1 has been disclosed to have regulatory functions in some diseases. However, the functions and related regulatory mechanisms of circCTNNB1 in lung cancer remain largely indistinct. The mRNA and protein expression levels were examined through real-time polymerase chain reaction (RT-qPCR) and western blot. The cell proliferation was tested through CCK-8 assay. The cell migration and invasion were confirmed through Transwell assays. The cell senescence was evaluated through SA-β-gal assay. The binding ability between miR-186-5p and circCTNNB1 (or YY1) was verified through luciferase reporter and RIP assays. In this study, the higher expression of circCTNNB1 was discovered in lung cancer tissues and cell lines and resulted in poor prognosis. In addition, circCTNNB1 facilitated lung cancer cell proliferation, migration, invasion, and suppressed cell senescence. Knockdown of circCTNNB1 retarded the Wnt pathway. Mechanism-related experiments revealed that circCTNNB1 combined with miR-186-5p to target YY1. Through rescue assays, YY1 overexpression could rescue decreased cell proliferation, migration, invasion, increased cell senescence, and retarded Wnt pathway mediated by circCTNNB1 suppression. Furthermore, YY1 acts as a transcription factor that can transcriptionally activate circCTNNB1 to form YY1/circCTNNB1/miR-186-5p/YY1 positive loop. Through in vivo assays, circCTNNB1 accelerated tumour growth in vivo. All findings revealed that a positive loop YY1/circCTNNB1/miR-186-5p/YY1 aggravated lung cancer progression by modulating the Wnt pathway.

Wnt signaling pathway in spinal cord injury: from mechanisms to potential applications

Spinal cord injury (SCI) denotes damage to both the structure and function of the spinal cord, primarily manifesting as sensory and motor deficits caused by disruptions in neural transmission pathways, potentially culminating in irreversible paralysis. Its pathophysiological processes are complex, with numerous molecules and signaling pathways intricately involved. Notably, the pronounced upregulation of the Wnt signaling pathway post-SCI holds promise for neural regeneration and repair. Activation of the Wnt pathway plays a crucial role in neuronal differentiation, axonal regeneration, local neuroinflammatory responses, and cell apoptosis, highlighting its potential as a therapeutic target for treating SCI. However, excessive activation of the Wnt pathway can also lead to negative effects, highlighting the need for further investigation into its applicability and significance in SCI. This paper provides an overview of the latest research advancements in the Wnt signaling pathway in SCI, summarizing the recent progress in treatment strategies associated with the Wnt pathway and analyzing their advantages and disadvantages. Additionally, we offer insights into the clinical application of the Wnt signaling pathway in SCI, along with prospective avenues for future research direction.

The roles of circular RNAs in nerve injury and repair

Nerve injuries significantly impact the quality of life for patients, with severe cases posing life-threatening risks. A comprehensive understanding of the pathophysiological mechanisms underlying nerve injury is crucial to the development of effective strategies to promote nerve regeneration. Circular RNAs (circRNAs), a recently characterized class of RNAs distinguished by their covalently closed-loop structures, have been shown to play an important role in various biological processes. Numerous studies have highlighted the pivotal role of circRNAs in nerve regeneration, identifying them as potential therapeutic targets. This review aims to succinctly outline the latest advances in the role of circRNAs related to nerve injury repair and the underlying mechanisms, including peripheral nerve injury, traumatic brain injury, spinal cord injury, and neuropathic pain. Finally, we discuss the potential applications of circRNAs in drug development and consider the potential directions for future research in this field to provide insights into circRNAs in nerve injury repair.

Circ_0006640 transferred by bone marrow-mesenchymal stem cell-exosomes suppresses lipopolysaccharide-induced apoptotic, inflammatory and oxidative injury in spinal cord injury

BACKGROUND

Emerging proofs have shown that differentially expressed circular RNAs (circRNAs) are closely associated with the pathophysiological process of spinal cord injury (SCI). Mesenchymal stem cell (MSC)-exosomes have been demonstrated to possess favorable therapeutic effects in diseases. Herein, this work aimed to investigate the action of circ_0006640 transferred by MSC-exosomes functional recovery after SCI.

METHODS

SCI animal models were established by spinal cord contusion surgery in mice and lipopolysaccharide (LPS)-stimulated mouse microglial cell line BV2. Levels of genes and proteins were detected by qRT-PCR and Western blot. Properties of BV2 cells were characterized using CCK-8 assay, flow cytometry and ELISA analysis. The oxidative stress was evaluated. Dual-luciferase reporter assay was used for verifying the binding between miR-382-5p and circ_0006640 or IGF-1 (Insulin-like Growth Factor 1). Exosome separation was conducted by using the commercial kit.

RESULTS

Circ_0006640 expression was lower in SCI mice and LPS-induced microglial cells. Circ_0006640 overexpression protected microglial cells from LPS-induced apoptotic, inflammatory and oxidative injury. Mechanistically, circ_0006640 directly sponged miR-382-5p, which targeted IGF-1. MiR-382-5p was increased, while IGF-1 was decreased in SCI mice and LPS-induced microglial cells. Knockdown of miR-382-5p suppressed apoptosis, inflammation and oxidative stress in LPS-induced microglial cells, which were reversed by IGF-1 deficiency. Moreover, miR-382-5p up-regulation abolished the protective functions of circ_0006640 in LPS-induced microglial cells. Additionally, circ_0006640 was packaged into MSC-exosomes and could be transferred by exosomes. Exosomal circ_0006640 also had protective effects on microglial cells via miR-382-5p/IGF-1 axis.

CONCLUSION

Circ_0006640 transferred by BMSC-exosomes suppressed LPS-induced apoptotic, inflammatory and oxidative injury via miR-382-5p/IGF-1 axis, indicating a new insight into the clinical application of exosomal circRNA-based therapeutic in the function recovery after SCI.

Circ-SUZ12 Protects Cardiomyocytes from Hypoxia-Induced Dysfunction Through Upregulating SUZ12 Expression to Activate Wnt/β-catenin Signaling Pathway

Acute myocardial infarction (AMI) is a common coronary artery disease. This study attempted to reveal the impact of circ-SUZ12 (hsa_circ_0042961) on cardiomyocyte injury after exposure to hypoxia.Circ-SUZ12 was screened out from the GEO dataset GSE169594. RNA expression and protein level were detected by quantitative real-time PCR (qRT-PCR) and Western blot, respectively. The characteristics of circ-SUZ12 were identified by measuring its resistance to Rnase R or actinomycin D (Act D) treatment. CCK-8 and EdU assays were performed to explore the viability of AC16 cells. Cell apoptosis was assessed through TUNEL assay and flow cytometry analysis. Mechanism experiments were performed to investigate the downstream molecular mechanism of circ-SUZ12.Circ-SUZ12 was highly expressed in blood samples of AMI patients in the GEO dataset and lowly expressed in hypoxia-treated cardiomyocytes. Overexpression of circ-SUZ12 reversed hypoxia-induced cardiomyocyte injury. Circ-SUZ12 regulated SUZ12 polycomb repressive complex 2 subunit (SUZ12) expression by recruiting FUS protein. SUZ12 activated the Wnt/β-catenin signaling pathway by increasing the H3K27me3 level in microRNA (miR)-526b-5p promoter to release catenin beta 1 (CTNNB1). CTNNB1 depletion reversed the effect of circ-SUZ12 on the viability and apoptosis of hypoxia-induced cardiomyocytes.Circ-SUZ12 protects cardiomyocytes from hypoxia-induced dysfunction through upregulating SUZ12 expression to activate the Wnt/β-catenin signaling pathway.

Potential value of differentially expressed circular RNAs derived from circulating exosomes in the pathogenesis of rat spinal cord injury

Spinal cord injury (SCI) remains one kind of devastating neurological damage, and specific molecular mechanisms involved need to be understood deeply. Currently, circular RNAs (circRNAs), as a newly discovered type of non-coding RNAs (ncRNAs), have been under active investigation. Through functional interactions with disease-associated microRNAs (miRNAs), exosome-derived circRNAs have been extensively implicated in various organ pathogenesis. Nevertheless, the functional involvement of circulating circRNAs in SCI onset, progression as well as repair remains poorly explored until now. Of note, there still lacks clinical and experimental evidence in this regard. To obtain some relevant knowledge in this field, this study was originally designed to have a general overview of differentially expressed circRNAs derived from circulating exosomes in SCI rats in comparison with the control rats. It turned out that 709 types of downregulated circRNAs and 346 kinds of upregulated circRNAs were preliminarily screened out. Functional enrichment analyses including kyoto encyclopedia of genes and genomes (KEGG) pathway and gene ontology (GO) were performed to evaluate the possible biological functions of upregulated as well as downregulated circRNAs involved in SCI. Furthermore, five types of upregulated circulating circRNAs including chr4:208359914–208362182+, chr15:20088296–20092102+, chr1:175098934– 175134845–, chr1:175099657– 175128203–, and chr1:175104454– 175134845–, and plus five kinds of downregulated circulating circRNAs including chr11:74154652– 74159524–, chr12:45412398– 45412635–, chr7:137630261– 137648924–, chr6:6280974–6281188+, and chr4:225251864–225254087+, were verified through reverse transcription-polymerase chain reaction (RT-PCR). At last, taking these differentially expressed circRNAs in the center, the circRNA-miRNA-mRNA gene interaction network was constructed to predict the possible functionalities of circRNAs in SCI through anticipating specific interactive miRNAs, giving new insights into how circRNAs contribute to this pathological process. Taken together, these findings suggest the possible involvement and functional significance of circRNAs in SCI.