Hsa_circ_0000437 upregulates and promotes disease progression in rheumatic valvular heart disease

Let‑7f‑5p Regulated by Hsa_circ_0000437 Ameliorates Bleomycin-Induced Skin Fibrosis

The current treatment of skin fibrosis is limited in its effectiveness due to a lack of understanding of the underlying mechanisms. Previous research has shown a connection between microRNAs (miRNAs) and the development of skin fibrosis. Therefore, investigating miRNA for the treatment of skin fibrotic diseases is highly important and merits further exploration. In this study, we have discovered that let-7f-5p could suppress the proliferation, migration, and expression of collagen type I alpha 1 (COL1A1) in human dermal fibroblasts (HDFs). It was further determined that let-7f-5p could target thrombospondin-1 (THBS1), thereby inhibiting the TGF-β2/Smad3 signaling pathway and exerting its biological effects. Additionally, let-7f-5p is regulated by Hsa_circ_0000437, which acts as a sponge molecule for let-7f-5p and consequently regulates the biological function of HDFs. Furthermore, our findings indicate that in vivo overexpression of let-7f-5p leads to a reduction in dermal thickness and COL1A1 expression, effectively inhibiting the progression of bleomycin (BLM)-induced skin fibrosis in mice. Hence, our research enhances the comprehension of the Hsa_circ_0000437/let-7f-5p/THBS1/TGF-β2/Smad3 regulatory network, highlighting the potential of let-7f-5p as a therapeutic approach for the treatment of skin fibrosis.

Exploring the Multifaceted Biologically Relevant Roles of circRNAs: From Regulation, Translation to Biomarkers

CircRNAs are a category of regulatory RNAs that have garnered significant attention in the field of regulatory RNA research due to their structural stability and tissue-specific expression. Their circular configuration, formed via back-splicing, results in a covalently closed structure that exhibits greater resistance to exonucleases compared to linear RNAs. The distinctive regulation of circRNAs is closely associated with several physiological processes, as well as the advancement of pathophysiological processes in several human diseases. Despite a good understanding of the biogenesis of circular RNA, details of their biological roles are still being explored. With the steady rise in the number of investigations being carried out regarding the involvement of circRNAs in various regulatory pathways, understanding the biological and clinical relevance of circRNA-mediated regulation has become challenging. Given the vast landscape of circRNA research in the development of the heart and vasculature, we evaluated cardiovascular system research as a model to critically review the state-of-the-art understanding of the biologically relevant functions of circRNAs. We conclude the review with a discussion of the limitations of current functional studies and provide potential solutions by which these limitations can be addressed to identify and validate the meaningful and impactful functions of circRNAs in different physiological processes and diseases.

Recent Advances of Using Exosomes as Diagnostic Markers and Targeting Carriers for Cardiovascular Disease

Cardiovascular diseases (CVDs) are the leading cause of human death worldwide. Exosomes act as endogenous biological vectors; they possess advantages of low immunogenicity and low safety risks, also providing tissue selectivity, including the inherent targeting the to heart. Therefore, exosomes not only have been applied as biomarkers for diagnosis and therapeutic outcome confirmation but also showed potential as drug carriers for cardiovascular targeting delivery. This review aims to summarize the progress and challenges of exosomes as novel biomarkers, especially many novel exosomal noncoding RNAs (ncRNAs), and also provides an overview of the improved targeting functions of exosomes by unique engineered approaches, the latest developed administration methods, and the therapeutic effects of exosomes used as the biocarriers of medications for cardiovascular disease treatment. Also, the possible therapeutic mechanisms and the potentials for transferring exosomes to the clinic for CVD treatment are discussed. The advances, in vivo and in vitro applications, modifications, mechanisms, and challenges summarized in this review will provide a general understanding of this promising strategy for CVD treatment.

Dysregulation of circRNAs in rheumatoid arthritis, with special emphasis on circRNAs secreted by exosomes and the crosstalk between circRNAs and RNA methylations

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease caused by a variety of unknown factors. It mainly occurs in the small joints of hands and feet, leading to cartilage destruction and bone erosion. Various pathologic mechanisms such as exosomes and RNA methylations are involved in the pathogenesis of RA.

METHODS

This work searches PubMed, Web of Science (SCIE) and Science Direct Online (SDOL) databases, it role of abnormally expressed circulating RNAs (circRNAs) in the pathogenesis of RA was summarized. And the relationship between circRNAs and exosomes and methylations.

RESULTS

Both the abnormal expression of circRNAs and the sponge effect of circRNAs on microRNAs (miRNAs) affect the pathogenesis of RA by regulating target genes. CircRNAs affect the proliferation, migration and inflammatory reaction of RA-fibroblast-like synovial cells (FLSs), circRNAs in peripheral blood mononuclear cells (PBMCs) and macrophages also participate in the pathological mechanism of RA (Fig. 1). CircRNAs in exosomes are closely related to the pathogenesis of RA. In addition, exosomal circRNAs and the relationship between circRNAs and RNA methylations are closely related to the pathogenesis of RA.

CONCLUSION

CircRNAs play an important role in the pathogenesis of RA and have the potential to be a new target for the diagnosis and treatment of RA. However, the development of mature circRNAs for clinical application is not a small challenge.

The Landscape of Circular RNAs in Cardiovascular Diseases

Cardiovascular disease (CVD) remains the leading cause of mortality globally. Circular RNAs (circRNAs) have attracted extensive attention for their roles in the physiological and pathological processes of various cardiovascular diseases (CVDs). In this review, we briefly describe the current understanding of circRNA biogenesis and functions and summarize recent significant findings regarding the roles of circRNAs in CVDs. These results provide a new theoretical basis for diagnosing and treating CVDs.

Upregulation of hsa_circ_0000977 participates in esophageal squamous cancer progression by sponging miR-874-3p

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most common clinical malignancies of the digestive system, characterized by high mortality but not evident early symptoms. Molecular markers for diagnostic and outcome prediction are urgently needed. Circular RNAs might play essential roles in the progression of ESCC.

METHODS

Hsa_circ_0000977 was identified using circRNA microarrays and qRT-PCR. The diagnostic value of hsa_circ_0000977 was calculated. We also examined in vitro cell functions in ECA109 and TE12 ESCC cells to determine the effect of hsa_circ_0000977. A dual-luciferase reporter vector validated the binding of hsa_circ_0000977 to miR-874-3p.

RESULTS

The top 10 significantly upregulated circRNAs from microarray assays were hsa_circ_0000977, hsa_circ_0006220, hsa_circ_0043278, hsa_circ_0000691, hsa_circ_0000288, hsa_circ_0000367, hsa_circ_0021647, hsa_circ_0006440, hsa_circRNA_405571 and hsa_circRNA_100790, while the top 10 significantly downregulated circRNAs were hsa_circ_0008389, hsa_circ_0089763, hsa_circ_0089762, hsa_circ_0000102, hsa_circ_0001714, hsa_circ_0089761, hsa_circ_0007326, hsa_circ_0001549, hsa_circ_0005133 and hsa_circRNA_405965. Hsa_circ_0000977 was significantly upregulated in ESCC (p < 0.01) and had diagnostic value in ESCC. The hsa_circ_0000977 expression level was related to the pT stage and numbers of lymph nodes in ESCC patients. Elevated hsa_circ_0000977 promoted cell proliferation, migration and inhibited apoptosis in ESCC cells. Hsa_circ_0000977 might function as a micro-RNA sponge to competitively bind miR-874-3p.

CONCLUSION

Disordered hsa_circ_0000977 expression can promote carcinogenesis in ESCC and might serve as a diagnostic biomarker to evaluate the occurrence and development of esophageal cancer.

Hsa_circ_0003748 promotes disease progression in rheumatic valvular heart disease by sponging miR-577

The diagnosis and treatment of rheumatic valvular heart disease (RVHD) require substantial improvements. Studies found that circular RNAs (circRNAs) are involved in the progression of cardiovascular diseases. We screened target hsa_circ_0003748 by circRNA microarrays uploaded to a database. We used fluorescence in situ hybridization to determine the cellular location of hsa_circ_0003748. A dual-luciferase reporter gene assay revealed that has_circ_0003748 might bind the miRNA miR-577. In hVIC cells (an RVHD cell line), Cell Counting Kit-8, Transwell, and flow cytometry assays measured proliferation, migration, and cell cycle and apoptosis, respectively. We found that hsa_circ_0003748 was localized in the cytoplasm; hsa_circ_0003748 promoted the proliferation and migration of hVIC cells, arrested the cell cycle in the G2/M phase, and inhibited apoptosis. These phenomena may result from hsa_circ_0003748 promoting RVHD after sponging miR-577. Bioinformatic analysis revealed that hsa_circ_0003748 might affect RVHD progression by affecting transcription and the MAPK signaling pathway, the Ras signaling pathway, the cAMP signaling pathway, the Rap1 signaling pathway, and other signaling pathways.