Friend or Foe: A Cancer Suppressor MicroRNA-34 Potentially Plays an Adverse Role in Vascular Diseases by Regulating Cell Apoptosis and Extracellular Matrix Degradation

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.

Non-coding RNAs modulate function of extracellular matrix proteins

The extracellular matrix (ECM) creates a multifaceted system for the interaction of diverse structural proteins, matricellular molecules, proteoglycans, hyaluronan, and various glycoproteins that collaborate and bind with each other to produce a bioactive polymer. Alterations in the composition and configuration of ECM elements influence the cellular phenotype, thus participating in the pathogenesis of several human disorders. Recent studies indicate the crucial roles of non-coding RNAs in the modulation of ECM. Several miRNAs such as miR-21, miR-26, miR-19, miR-140, miR-29, miR-30, miR-133 have been dysregulated in disorders that are associated with disruption or breakdown of the ECM. Moreover, expression of MALAT1, PVT1, SRA1, n379519, RMRP, PFL, TUG1, TM1P3, FAS-AS1, PART1, XIST, and expression of other lncRNAs is altered in disorders associated with the modification of ECM components. In the current review, we discuss the role of lncRNAs and miRNAs in the modification of ECM and their relevance with the pathophysiology of human disorders such as cardiac/ lung fibrosis, cardiomyopathy, heart failure, asthma, osteoarthritis, and cancers.

Role of Exosomes in the Progression, Diagnosis, and Treatment of Gliomas

Gliomas are the most common primary malignant brain tumors associated with a low survival rate. Even after surgery, radiotherapy, and chemotherapy, gliomas still have a poor prognosis. Extracellular vesicles are a heterogeneous group of cell-derived membranous structures. Exosomes are a type of extracellular vesicles, their size ranges from 30 nm to 100 nm. Recent studies have proved that glioma cells could release numerous exosomes; therefore, exosomes have gained increasing attention in glioma-related research.

Recent studies have confirmed the importance of extracellular vesicles, particularly exosomes, in the development of brain tumors, including gliomas. Exosomes mediate intercellular communication in the tumor microenvironment by transporting biomolecules (proteins, lipids, deoxyribonucleic acid, and ribonucleic acid); thereby playing a prominent role in tumor proliferation, differentiation, metastasis, and resistance to chemotherapy or radiation. Given their nanoscale size, exosomes can traverse the blood-brain barrier and promote tumor progression by modifying the tumor microenvironment. Based on their structural and functional characteristics, exosomes are demonstrating their value not only as diagnostic and prognostic markers, but also as tools in therapies specifically targeting glioma cells.

Therefore, exosomes are a promising therapeutic target for the diagnosis, prognosis, and treatment of malignant gliomas. More research will be needed before exosomes can be used in clinical applications. Here, we describe the exosomes, their morphology, and their roles in the diagnosis and progression of gliomas. In addition, we discuss the potential of exosomes as a therapeutic target/drug delivery system for patients with gliomas.

LncRNA BANCR induced vascular smooth muscle cell proliferation by downregulating miR-34c methylation in atherosclerosis

Aberrant vascular smooth muscle cell (VSMCs) proliferation involves in the development of atherosclerosis. It reported that Long noncoding BRAF-activated noncoding RNA (BANCR) and miR-34c played opposite roles in the regulation of the proliferation of VSMCs, indicating that there might be a potential interaction between them. This study was to investigate the relationship between BANCR and miR-34c in atherosclerosis. Blood (5 ml) was obtained from 56 patients with atherosclerosis and 56 healthy volunteers after they were fasted overnight, and plasma was extracted from the blood. Human Aortic Smooth Muscle Cells (HASMCs) were used to perform in vitro cell experiments. RT-qPCR was performed to measure the expression of BANCR and miR-34c in plasma and HASMCs. Dual luciferase reporter assay detected the interaction between BANCR and miR-34c. CCK-8 assay was used to assess the effects of BANCR and miR-34c overexpression on the proliferation of HASMCs. Western blotting was used to assess the effects of BANCR and miR-34c overexpression on the protein expression of HMGB1, TNF-ɑ and Bcl-2. In this study, we found that BANCR was upregulated, while miR-34c was downregulated in atherosclerosis. Bioinformatics analysis showed that BANCR and miR-34c could directly interact with each other. Moreover, overexpression of BANCR could decrease the expression of miR-34c in HASMCs, but overexpression of miR-34c could not affect the expression of BANCR. Furthermore, overexpression of BACNR increased miR-34c methylation, and knockdown of endogenous BANCR decreased miR-34c methylation. In addition, overexpression of BANCR reduced the effects of miR-34c on HASMCs proliferation and reversed the effects of miR-34c on HMGB1, TNF-ɑ and Bcl-2 expression. BANCR overexpression could induce HASMCs proliferation by downregulating the miR-34c methylation. Therefore given BANCR upregulation in atherosclerosis, its expression may be considered as a novel and useful biomarker for atherosclerosis prevention and prognosis. However considering the possible effects of other underlying diseases on both BANCR expression and miR-34c in atherosclerosis, further investigation is suggested for future research.

MicroRNAs are critical in regulating smooth muscle cell mineralization and apoptosis during vascular calcification

Vascular calcification refers to the pathological deposition of calcium and phosphate minerals into the vasculature. It is prevalent in atherosclerosis, ageing, type 2 diabetes mellitus and chronic kidney disease, thus, increasing morbidity and mortality from these conditions. Vascular calcification shares similar mechanisms with bone mineralization, with smooth muscle cells playing a critical role in both processes. In the last decade, a variety of microRNAs have been identified as key regulators for the differentiation, phenotypic switch, proliferation, apoptosis, cytokine production and matrix deposition in vascular smooth muscle cells during vascular calcification. Therefore, this review mainly discusses the roles of microRNAs in the pathophysiological mechanisms of vascular calcification in smooth muscle cells and describes several interventions against vascular calcification by regulating microRNAs. As the exact mechanisms of calcification remain not fully elucidated, having a better understanding of microRNA involvement in vascular calcification may give impetus to development of novel therapeutics for the control and treatment of vascular calcification.

Biomechanical signal communication in vascular smooth muscle cells

Biomechanical stresses are closely associated with cardiovascular development and diseases. In vivo, vascular smooth muscle cells are constantly stimulated by biomechanical factors caused by increased blood pressure leading to the non-specific activation of cell transmembrane proteins. Thus, various intracellular signal molecules are simultaneously activated via signaling cascades, which are closely related to alterations in the differentiation, phenotype, inflammation, migration, pyroptosis, calcification, proliferation, and apoptosis of vascular smooth muscle cells. Meanwhile, mechanical stress-induced miRNAs and epigenetics modification on vascular smooth muscle cells play critical roles as well. Eventually, the overall pathophysiology of the cells is altered, resulting in the development of many major clinical diseases, including hypertension, atherosclerosis, grafted venous atherosclerosis, and aneurysm, among others. In this paper, important advances in mechanical signal communication in vascular smooth muscle cells are reviewed.

Indoxyl sulfate promotes the atherosclerosis through up-regulating the miR-34a expression in endothelial cells and vascular smooth muscle cells in vitro

Atherosclerosis (AS) is one of the most common cardiovascular events in patients with chronic renal insufficiency (CRI). During the development of CRI, uremic toxins, including indoxyl sulfate (IS), are pivotal risk factors for AS. However, the underlying mechanism between AS and IS has not been fully elucidated. The present study was designed to test our hypothesis that IS promotes the AS by regulating viability, proliferation, migration and apoptosis of endothelial cells and vascular smooth muscle cells. In this present study, our date showed that IS inhibited the cell viability of human umbilical vein endothelial cells (HUVECs) and human aortic vascular smooth muscle cells (HA-VSMCs) in a dose-dependent manner (P < .05). Moreover, IS inhibited the proliferation, migration and induced apoptosis of HUVECs and HA-VSMCs significantly (P < .05). However, inhibition of the miR-34a abolished these effects of IS in vitro, indicating that miR-34a is involved in the development of AS induced by IS. In addition, the luciferase reporter gene assay showed that up-regulating of miR-34a inhibited the Notch1 transcriptional activity remarkably (P < .05). The expression of Notch1 decreased after IS treatment, while miR-34a inhibitor attenuated this effect. Moreover, the expression of miR-34a-related proteins Wnt-1, Jag1, E2F1 and SIRT1 decreased, while the expression of p53 increased in HUVECs and HA-VSMCs after IS treatment. Consistently, blockage of miR-34a abolished the remarkable effects on protein expressions induced by IS. Taken together, this study showed that IS can inhibit the proliferation, migration and promote apoptosis of HUVECs and HA-VSMCs through the Notch1 signal and miR-34a-related proteins by up-regulating miR-34a. These findings may provide new insights into the underlying mechanism of AS in CRI.

Forefront: MiR-34a-Knockout Mice with Wild Type Hematopoietic Cells, Retain Persistent Fibrosis Following Lung Injury

MicroRNAs (miRs) are known to limit gene expression at the post-transcriptional level and have important roles in the pathogenesis of various conditions, including acute lung injury (ALI) and fibrotic diseases such as idiopathic pulmonary fibrosis (IPF). In this study, we found increased levels of miR-34 at times of fibrosis resolution following injury, in myofibroblasts from Bleomycin-treated mouse lungs, which correlates with susceptibility to cell death induced by immune cells. On the contrary, a substantial downregulation of miR-34 was detected at stages of evolution, when fibroblasts resist cell death. Concomitantly, we found an inverse correlation between miR-34 levels with that of the survival molecule FLICE-like inhibitory protein (FLIP) in lung myofibroblasts from humans with IPF and the experimental model. Forced upregulation of miR-34 with miR-34 mimic in human IPF fibrotic-lung myofibroblasts led to decreased cell survival through downregulation of FLIP. Using chimeric miR-34 knock-out (KO)-C57BL/6 mice with miR34KO myofibroblasts but wild-type (WT) hematopoietic cells, we found, in contrast to WT mice, increased and persistent FLIP levels with a more severe fibrosis and with no signs of resolution as detected in pathology and collagen accumulation. Moreover, a mimic of miR-34a decreased FLIP expression and susceptibility to cell death was regained in miR-34KO fibroblasts. Through this study, we show for the first time an inverse correlation between miR-34a and FLIP expression in myofibroblasts, which affects survival, and accumulation in lung fibrosis. Reprogramming fibrotic-lung myofibroblasts to regain susceptibility to cell-death by specifically increasing their miR34a and downregulating FLIP, may be a useful strategy, enabling tissue regeneration following lung injury.