Expression and Functional Analysis of lncRNAs Involved in Platelet-Derived Growth Factor-BB-Induced Proliferation of Human Aortic Smooth Muscle Cells

A Novel Hidden Protein p-414aa Encoded by circSETD2(14,15) Inhibits Vascular Remodeling

BACKGROUND

Phenotypic switching of vascular smooth muscle cells (VSMCs), leading to neointimal hyperplasia, is a fundamental cause of vascular remodeling diseases such as atherosclerosis and hypertension. Novel hidden proteins encoded by circular RNAs play crucial roles in disease progression, yet their involvement in vascular remodeling diseases has not been comprehensively studied. This study identifies a novel protein derived from a circular RNA in VSMCs and demonstrates its potential role in regulating vascular remodeling.

METHODS

Cell proliferation assays were performed to investigate the effects of circSETD2(14,15) on VSMC proliferation. Techniques such as vector construction, immunoprecipitation-mass spectrometry, and dual-luciferase reporter gene were used to confirm that circSETD2(14,15) encoded a novel protein, p-414aa. The interaction between p-414aa and HuR (human antigen R) was validated with techniques such as coimmunoprecipitation, mass spectrometry, and proximity ligation assay. Through experiments including RNA sequencing and RNA immunoprecipitation, the interaction between HuR and C-FOS (C-Fos proto-oncogene) mRNA was revealed. The role of p-414aa in neointimal hyperplasia was assessed with a carotid artery ligation model in male mice.

RESULTS

Overexpression of circSETD2(14,15) inhibits VSMC phenotypic switching. The novel protein p-414aa, encoded by circSETD2(14,15), interacts with HuR to reduce C-FOS mRNA stability, thereby suppressing VSMC proliferation and ultimately inhibiting neointimal hyperplasia in male mice.

CONCLUSIONS

We uncover a novel hidden protein derived from circSETD2(14,15), called p-414aa, that inhibits vascular remodeling. CircSETD2(14,15) and p-414aa may serve as potential therapeutic targets for vascular remodeling diseases.

Hsa_circ_0001304 promotes vascular neointimal hyperplasia accompanied by autophagy activation

Aberrant autophagy in vascular smooth muscle cells (VSMCs) is associated with the progression of vascular remodeling diseases caused by neointimal hyperplasia. Platelet-derived growth factor-BB (PDGF-BB)-induced vascular remodeling is accompanied by autophagy activation, however, the involvement of circular RNAs (circRNAs) remains unclear. Here, we show the role of PDGF-BB-regulated hsa_circ_0001304 (circ-1304) in neointimal hyperplasia and its potential involvement in VSMC autophagy, while also elucidating the potential mechanisms. Functionally, overexpression of circ-1304 promotes VSMC autophagy in vitro and exacerbates neointimal hyperplasia in vivo, and this exacerbation is accompanied by autophagy activation. Mechanistically, circ-1304 acts as a sponge for miR-636, resulting in increased protein levels of YTHDF2. Subsequently, the YTHDF2 protein promotes the degradation of mTOR mRNA by binding to the latter's m6A modification sites. We demonstrate that PDGF-BB activates VSMC autophagy via circRNA regulation. Therefore, circ-1304 may serve as a potential therapeutic target for vascular remodeling diseases.

Hsa_circ_0001402 alleviates vascular neointimal hyperplasia through a miR-183-5p-dependent regulation of vascular smooth muscle cell proliferation, migration, and autophagy

INTRODUCTION

Vascular neointimal hyperplasia, a pathological process observed in cardiovascular diseases such as atherosclerosis and pulmonary hypertension, involves the abundant presence of vascular smooth muscle cells (VSMCs). The proliferation, migration, and autophagy of VSMCs are associated with the development of neointimal lesions. Circular RNAs (circRNAs) play critical roles in regulating VSMC proliferation and migration, thereby participating in neointimal hyperplasia. However, the regulatory roles of circRNAs in VSMC autophagy remain unclear.

OBJECTIVES

We aimed to identify circRNAs that are involved in VSMC autophagy-mediated neointimal hyperplasia, as well as elucidate the underlying mechanisms.

METHODS

Dual-luciferase reporter gene assay was performed to validate two competing endogenous RNA axes, hsa_circ_0001402/miR-183-5p/FKBP prolyl isomerase like (FKBPL) and hsa_circ_0001402/miR-183-5p/beclin 1 (BECN1). Cell proliferation and migration analyses were employed to investigate the effects of hsa_circ_0001402, miR-183-5p, or FKBPL on VSMC proliferation and migration. Cell autophagy analysis was conducted to reveal the role of hsa_circ_0001402 or miR-183-5p on VSMC autophagy. The role of hsa_circ_0001402 or miR-183-5p on neointimal hyperplasia was evaluated using a mouse model of common carotid artery ligation.

RESULTS

Hsa_circ_0001402 acted as a sponge for miR-183-5p, leading to the suppression of miR-183-5p expression. Through direct interaction with the coding sequence (CDS) of FKBPL, miR-183-5p promoted VSMC proliferation and migration by decreasing FKBPL levels. Besides, miR-183-5p reduced BECN1 levels by targeting the 3'-untranslated region (UTR) of BECN1, thus inhibiting VSMC autophagy. By acting as a miR-183-5p sponge, overexpression of hsa_circ_0001402 increased FKBPL levels to inhibit VSMC proliferation and migration, while simultaneously elevating BECN1 levels to activate VSMC autophagy, thereby alleviating neointimal hyperplasia.

CONCLUSION

Hsa_circ_0001402, acting as a miR-183-5p sponge, increases FKBPL levels to inhibit VSMC proliferation and migration, while enhancing BECN1 levels to activate VSMC autophagy, thus alleviating neointimal hyperplasia. The hsa_circ_0001402/miR-183-5p/FKBPL axis and hsa_circ_0001402/miR-183-5p/BECN1 axis may offer potential therapeutic targets for neointimal hyperplasia.

miR-22-3p as a potential biomarker for coronary artery disease based on integrated bioinformatics analysis

Background: Coronary artery disease (CAD) is a common cardiovascular disease that has attracted attention worldwide due to its high morbidity and mortality. Recent studies have shown that abnormal microRNA (miRNA) expression is effective in CAD diagnoses and processes. However, the potential relationship between miRNAs and CAD remains unclear.

Methods: Microarray datasets GSE105449 and GSE28858 were downloaded directly from the Gene Expression Omnibus (GEO) to identify miRNAs involved in CAD. Target gene prediction and enrichment analyses were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG).

Results: There were nine differentially expressed miRNAs in CAD patients compared to the controls. A total of 352 genes were predicted and subjected to GO analysis, which showed that differentially expressed genes (DEGs) were mainly associated with axon guidance, neuron projection guidance, neuron-to-neuron synapses, and postsynaptic density. According to the KEGG pathway analysis, the most enriched pathways were those involved in transcriptional misregulation in cancer, growth hormone synthesis, secretion and action, endocrine resistance, axon guidance, and Cushing syndrome. Pathway analysis was mainly involved in the HIPPO and prion disease signaling pathways. Furthermore, a competing endogenous RNA (ceRNA) interaction network centered on miR-22-3p revealed eight related transcription factors in the cardiovascular system. The receiver operating characteristic (ROC) curve analysis suggested that miR-22-3p may be a better CAD predictor.

Conclusion: The results indicate that miR-22-3p may function in pathophysiological CAD processes. Our study potentiates miR-22-3p as a specific biomarker for diagnosing CAD.

Integrated analysis of tRNA-derived small RNAs in proliferative human aortic smooth muscle cells

Background

Abnormal proliferation of vascular smooth muscle cells (VSMCs) contributes to vascular remodeling diseases. Recently, it has been discovered that tRNA-derived small RNAs (tsRNAs), a new type of noncoding RNAs, are related to the proliferation and migration of VSMCs. tsRNAs regulate target gene expression through miRNA-like functions. This study aims to explore the potential of tsRNAs in human aortic smooth muscle cell (HASMC) proliferation.

Methods

High-throughput sequencing was performed to analyze the tsRNA expression profile of proliferative and quiescent HASMCs. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to validate the sequence results and subcellular distribution of AS-tDR-001370, AS-tDR-000067, AS-tDR-009512, and AS-tDR-000076. Based on the microRNA-like functions of tsRNAs, we predicted target promoters and mRNAs and constructed tsRNA–promoter and tsRNA–mRNA interaction networks. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to reveal the function of target genes. EdU incorporation assay, Western blot, and dual-luciferase reporter gene assay were utilized to detect the effects of tsRNAs on HASMC proliferation.

Results

Compared with quiescent HASMCs, there were 1838 differentially expressed tsRNAs in proliferative HASMCs, including 887 with increased expression (fold change > 2, p < 0.05) and 951 with decreased expression (fold change < ½, p < 0.05). AS-tDR-001370, AS-tDR-000067, AS-tDR-009512, and AS-tDR-000076 were increased in proliferative HASMCs and were mainly located in the nucleus. Bioinformatics analysis suggested that the four tsRNAs involved a variety of GO terms and pathways related to VSMC proliferation. AS-tDR-000067 promoted HASMC proliferation by suppressing p53 transcription in a promoter-targeted manner. AS-tDR-000076 accelerated HASMC proliferation by attenuating mitofusin 2 (MFN2) levels in a 3′-untranslated region (UTR)-targeted manner.

Conclusions

During HASMC proliferation, the expression levels of many tsRNAs are altered. AS-tDR-000067 and AS-tDR-000076 act as new factors promoting VSMC proliferation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00346-4.

Long Non-Coding RNAs Might Regulate Phenotypic Switch of Vascular Smooth Muscle Cells Acting as ceRNA: Implications for In-Stent Restenosis

Coronary in-stent restenosis is a late complication of angioplasty. It is a multifactorial process that involves vascular smooth muscle cells (VSMCs), endothelial cells, and inflammatory and genetic factors. In this study, the transcriptomic landscape of VSMCs’ phenotypic switch process was assessed under stimuli resembling stent injury. Co-cultured contractile VSMCs and endothelial cells were exposed to a bare metal stent and platelet-derived growth factor (PDGF-BB) 20 ng/mL. Migratory capacity (wound healing assay), proliferative capacity, and cell cycle analysis of the VSMCs were performed. RNAseq analysis of contractile vs. proliferative VSMCs was performed. Gene differential expression (DE), identification of new long non-coding RNA candidates (lncRNAs), gene ontology (GO), and pathway enrichment (KEGG) were analyzed. A competing endogenous RNA network was constructed, and significant lncRNA–miRNA–mRNA axes were selected. VSMCs exposed to “stent injury” conditions showed morphologic changes, with proliferative and migratory capacities progressing from G0-G1 cell cycle phase to S and G2-M. RNAseq analysis showed DE of 1099, 509 and 64 differentially expressed mRNAs, lncRNAs, and miRNAs, respectively. GO analysis of DE genes showed significant enrichment in collagen and extracellular matrix organization, regulation of smooth muscle cell proliferation, and collagen biosynthetic process. The main upregulated nodes in the lncRNA-mediated ceRNA network were PVT1 and HIF1-AS2, with downregulation of ACTA2-AS1 and MIR663AHG. The PVT1 ceRNA axis appears to be an attractive target for in-stent restenosis diagnosis and treatment.

Hsa_circ_0031608: A Potential Modulator of VSMC Phenotype in the Rupture of Intracranial Aneurysms

Background and Purpose

Phenotypic modulation of vascular smooth muscle cells (VSMCs) plays an important role in the development of intracranial aneurysms (IAs). Growing evidence has demonstrated that circular RNAs (circRNAs) may serve as a potential modulator of VSMC phenotype in various vascular diseases. This study aimed to assess the potential function of circRNAs in the rupture of IAs and VSMC phenotypic modulation.

Methods

Using surgically dissected human ruptured (n = 8) and unruptured (n = 8) IA lesions, differentially expressed circRNAs were screened by transcriptomic sequencing and verified using qRT-PCR. Based on the screened circRNA, we predicted and screened the combined miRNA and downstream mRNAs to construct circRNA-miRNA-mRNA networks. Further in vitro experiments were performed to investigate the relationship between the validated circRNA and the phenotypic switching of VSMCs.

Results

We found 1,373 differentially expressed genes in ruptured versus unruptured aneurysms. The top five dysregulated circRNAs were selected for qRT-PCR validation. We found hsa_circ_0031608 was both highly expressed in ruptured IAs and pro-inflammatory transformation of VSMCs. Then, a regulatory circRNA-miRNA-mRNA with one circRNA node, six miRNA nodes, and 84 mRNA nodes was constructed. GO analysis and KEGG pathway enrichment analysis were performed on mRNAs in the network. Then, a PPI network was built based on these mRNAs and five hub genes were identified (FOXO3, DICER1, CCND2, IGF1R, and TNRC6B) by the cytoHubba plugin in Cytoscape software. In vitro, overexpression of hsa_circ_0031608 influenced the expression of VSMC phenotypic markers validated by qPCR and Western blotting. Furthermore, hsa_circ_0031608 promoted the migration and proliferation capacity of VSMCs.

Conclusion

hsa_circ_0031608 regulated the phenotypic modulation of VSMCs and played an important role in the rupture of IAs. The specific mechanism should be further studied and confirmed.