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.

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.

Proteomics of restenosis model in LDLR-deficient hamsters coupled with the proliferative rat vascular smooth muscle cells reveals a new mechanism of vascular remodeling diseases.

A major pathological mechanism involved in vascular remodeling diseases is the proliferation and migration of vascular smooth muscle cells. The lipid distribution of golden hamsters is similar to that of humans, which makes them an excellent study model for studying the pathogenesis and molecular characteristics of vascular remodeling diseases. We performed proteomic analysis on Sprague Dawley rat VSMCs (rVSMCs) and restenosis hamsters with low-density lipoprotein receptor (LDLR) deficiency as part of this study. We have also performed the enrichment analysis of differentially modified proteins in regards to Gene Ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and protein domain. 1070 differentially abundant proteins were assessed in rVSMCs before and after platelet-derived growth factor-BB (PDGF-BB) stimulation. Specifically, 1246 proteins displayed significant differences in the restenosis model in LDLR-deficient hamsters. An analysis of crosstalk between LDLR+/- hamsters artery restenosis and proliferating rVSMCs revealed 130 differentially expressed proteins, including 67 up-regulated proteins and 63 downregulated proteins. Enrichment analysis with KEGG showed differential proteins to be mainly concentrated in metabolic pathways. There are numerous differentially abundant proteins but particularly two proteins (phosphofructokinase 1 of liver type and lactate dehydrogenase A) were found to be up-regulated by PDGF-BB stimulation of rVSMCs and in a restenosis model of hamsters with LDLR+/- expression. SIGNIFICANCE: Based on bioinformatics, we have found glycolysis pathway plays an important role in both the LDLR+/- hamsters restenosis model and the proliferation of rVSMCs. Some key glycolysis enzymes may likely be developed either as new biomarkers or drug targets for vascular remodeling diseases.

Long non-coding RNA TUG1 promotes the osteogenic differentiation of bone marrow mesenchymal stem cells by regulating the AMPK/mTOR/autophagy pathway.

Promoting the differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts is an effective strategy against osteoporosis. Long non-coding RNAs are closely implicated in BMSC osteogenic differentiation. The present study explored the expression pattern and biological role of taurine upregulated gene 1 (TUG1) in osteogenic differentiation. The expressions of TUG1 and osteogenic markers following the osteogenic induction of BMSCs were detected. The functional relevance of TUG1 was evaluated by performing gain- and loss-of-function tests. Inhibitors of AMP-activated protein kinase (AMPK) autophagy were applied to ascertain the effects of TUG1 on the osteogenic differentiation of BMSCs. TUG1 expression increased during the osteogenic differentiation of BMSCs. The overexpression of TUG1 was promoted, whereas the knockdown of TUG1 was suppressed, by BMSC osteogenic differentiation. Mechanically, TUG1 promoted the osteogenesis of BMSCs via the AMPK-mammalian target of rapamycin (mTOR)-autophagy signaling pathway. Blocking AMPK and autophagy could abrogate the osteogenic role of TUG1 in BMSCs. These results demonstrated that TUG1 promoted the osteogenic differentiation of BMSCs by regulating the AMPK/mTOR/autophagy axis, suggesting that targeting TUG1 may be a potential therapy for osteoporosis.

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

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is a common feature of many vascular remodeling diseases. Because long non-coding RNAs (lncRNAs) play a critical role in cardiovascular diseases, we analyzed the key lncRNAs that regulate VSMC proliferation. Microarray analysis identified 2,643 differentially expressed lncRNAs (DELs) and 3,720 differentially expressed coding genes (DEGs) between fetal bovine serum (FBS) starvation-induced quiescent human aortic smooth muscle cells (HASMCs) and platelet-derived growth factor-BB (PDGF-BB)-stimulated proliferative HASMCs. Gene Ontology and pathway analyses of the identified DEGs and DELs demonstrated that many lncRNAs were enriched in pathways related to cell proliferation. One of the upregulated lncRNAs in proliferative HASMC was HIF1A anti-sense RNA 2 (HIF1A-AS2). HIF1A-AS2 suppression decreased HASMC proliferation via the miR-30e-5p/CCND2 mRNA axis. We have thus identified key DELs and DEGs involved in the regulation of PDGF-BB induced HASMC proliferation. Moreover, HIF1A-AS2 promotes HASMC proliferation, suggesting its potential involvement in VSMC proliferative vascular diseases.

The Differentially Expressed Circular RNAs in the Substantia Nigra and Corpus Striatum of Nrf2-Knockout Mice.

BACKGROUND/AIMS: The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway plays a protective role in both acute neuronal damage and chronic neurodegeneration-related oxidative stress. Circular RNAs (circRNAs) are involved with various diseases in the central nervous system (CNS). This study aimed to identify the key circRNAs involved in Nrf2-neuroprotection against oxidative stress. METHODS: The differentially expressed circRNAs (DEcircRNAs) in the substantia nigra and corpus striatum between Nrf2 (-/-) and Nrf2 (+/+) mice were identified by microarray analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) was then used to validate the expression of selected DEcircRNAs in the substantia nigra and corpus striatum between Nrf2 (-/-) and Nrf2 (+/+) mice. Based on our previous microarray analysis of the differentially expressed mRNAs (DEmRNAs) in the substantia nigra and corpus striatum between Nrf2 (-/-) and Nrf2 (+/+) mice, the DEcircRNA-miRNA-DEmRNA interaction network was constructed. Functional annotation of DEmRNAs that shared the same binding miRNAs with DEcircRNAs was performed using gene ontology (GO) and pathway analyses. RESULTS: A total of 65 and 150 significant DEcircRNAs were obtained in the substantia nigra and corpus striatum of Nrf2 (-/-) mice, respectively, and seventeen shared DEcircRNAs were found in both these two tissues. The qRT-PCR results were generally consistent with the microarray results. The DEcircRNA-miRNA-DEmRNA interaction network and pathway analysis indicated that mmu_circRNA_34132, mmu_circRNA_017077 and mmu-circRNA-015216 might be involved with Nrf2-mediated neuroprotection against oxidative stress. Mmu_circRNA_015216 and mmu_circRNA_017077 might play roles in the Nrf2-related transcriptional misregulation and Nrf2-mediated processes of rheumatoid arthritis, respectively. In addition to these two processes, mmu_circRNA_34132 may be a potential regulator of Nrf2-mediated protection for diabetes mellitus and Nrf2-mediated defence against ROS in hearts. CONCLUSION: In conclusion, our study identified the key DEcircRNAs in the substantia nigra and corpus striatum of Nrf2 (-/-) mice, which might provide new clues for further exploring the mechanism of Nrf2-mediated neuroprotection against oxidative stress and other Nrf2-mediated processes.