MiR-200c-3p promotes ox-LDL-induced endothelial to mesenchymal transition in human umbilical vein endothelial cells through SMAD7/YAP pathway

Endothelial-Mesenchymal Transition and Possible Role of Cytokines in Streptozotocin-Induced Diabetic Heart

Background: Although endothelial mesenchymal transition (EndMT) has been characterized as a basic process in embryogenesis, EndMT is the mechanism that accelerates the development of cardiovascular diseases, including heart failure, aging, and complications of diabetes or hypertension as well. Endothelial cells lose their distinct markers and take on a mesenchymal phenotype during EndMT, expressing distinct products. Methods: In this study, type 1 Diabetes mellitus (T1DM) was induced in rats with streptozotocin (STZ) by intraperitoneal injection at a 60 mg/kg dose. Diabetic rats were randomly divided into two groups, namely, control and diabetic rats, for 4 weeks. Heart, aorta, and plasma samples were collected at the end of 4 weeks. Sequentially, biochemical parameters, cytokines, reactive oxygen species (ROS), protein expression of EndMT markers (Chemokine C-X-C motif ligand-1 (CXCL-1), vimentin, citrullinated histone H3 (H3Cit), α-smooth muscle actin (α-SMA), and transforming growth factor beta (TGF-β) and versican), components of the extracellular matrix (matrix metalloproteinase 2 (MMP-2), tissue inhibitor of metalloproteinase-1(TIMP-1), and discoidin domain tyrosine kinase receptor 2 (DDR-2)) were detected by ELISA or Western blot, respectively. Results: Cytokines and ROS were increased in diabetic hearts, which induced partial EndMT. Among EndMT markers, histone citrullination, α-SMA, and CXCL-1 were increased; vimentin was decreased in DM. The endothelial marker endothelin-1 was significantly higher in the aortas of DM rats. Interestingly, TGF-β showed a significant decrease in the diabetic heart, plasma, and aorta. Additionally, MMP-2/TIMP-1 levels also decreased in DM. Conclusions: To sum up, the identification of molecules and regulatory pathways involved in EndMT provided novel therapeutic approaches for cardiac pathophysiological conditions.

Downregulated Expression of miR-200c-3p in Plasma Exosome as a Potential Biomarker in Takayasu's Arteritis

Our previous work identified several differentially expressed miRNAs (DEmiRNAs) in plasma exosomes from Takayasu's arteritis (TAK) patients. This study aimed to validate these findings and explore the correlation between DEmiRNAs and clinical parameters in untreated TAK. Plasma exosomes were isolated from 30 untreated TAK patients and 20 healthy controls. qPCR was used to quantify miR-34a-5p, miR-143-3p, miR-22-3p, miR-200c-3p, and miR-21-5p expression. Correlations between miRNA levels, clinical data, inflammation markers, and T helper cell frequencies were analyzed. The target genes of validated DEmiRNAs were identified using mirDIP, and pathway enrichment analysis was performed using GO/KEGG. The effect of validated DEmiRNAs on the MAPK pathway and proliferation in human aortic endothelial cells (HAECs) was investigated in vitro. Only miR-200c-3p expression was validated as significantly downregulated in plasma exosomes from untreated TAK patients. Lower miR-200c-3p levels correlated negatively with ITAS-2010 scores and were associated with relapsed disease. MiR-200c-3p levels also negatively correlated with circulating Th17.1 cell frequencies. In vitro, the TAK exosome treatment activated ERK1/2 and JNK pathways and promoted HAEC proliferation, which was inhibited by the miR-200c-3p mimic. The pathway enrichment analysis showed that the MAPK pathway may be involved. This study confirms the reduced miR-200c-3p expression in plasma exosomes from TAK patients, suggesting its potential as a biomarker for vascular inflammation. MiR-200c-3p may exert protective effects in TAK by suppressing MAPK pathway activation and EC proliferation.

siLOXL2 Inhibits Endothelial Inflammatory Response and EndMT Induced by ox-LDL

INTRODUCTION

Our research aimed to investigate the potential role and mechanism of lysyl oxidase (LOX)-like 2 (LOXL2) in atherosclerosis (AS) by using the human umbilical vein endothelial cells (HUVECs) stimulated by oxidized low-density lipoprotein (ox-LDL).

METHODS

HUVECs were treated with ox-LDL at different concentrations (0, 10, 25, 50, and 100 μg/mL) and incubated for 24 h. The transfection efficacy of siLOXL2 was investigated by Western blot and real-time quantitative polymerase chain reaction (RT-qPCR). Cell migration, intracellular ROS measurement, oxidative stress, enzyme-linked immunosorbent assay, and adhesion assays were carried out to examine the ox-LDL-induced HUVECs injury. RT-qPCR and Western blot were used to determine gene and protein expression levels.

RESULTS

LOXL2 protein expression increased in ox-LDL-induced endothelial cells (ECs). ox-LDL + siLOXL2 significantly inhibited the migration ability of HUVECs and reduced the expression of vascular endothelial growth factor A (VEGFA) and matrix metalloproteinase 9 gene expressions (all, p < 0.05). The ox-LDL + siLOXL2 significantly reduced intracellular ROS production and inhibited the expression of Malondialdehyde, whereas it markedly enhanced superoxide dismutase and catalase (all, p < 0.05). Supernatant levels of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were significantly attenuated by the ox-LDL + siLOXL2 treatment (all, p < 0.05). ox-LDL + siLOXL2 markedly suppressed the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 (all, p < 0.05). ox-LDL + siLOXL2 treatment remarkably reduced the expression of α-smooth muscle actin and vimentin, while increased CD31 and von Willebrand factor gene expression (all, p < 0.05).

CONCLUSION

LOXL2 silencing is protected against ox-LDL-induced EC dysfunction, and the mechanism may be related to the inhibition of the EndMT pathway.

Circulating microRNAs in Carotid Atherosclerosis: Complex Interplay and Possible Associations with Atherothrombotic Stroke

Atherosclerosis is a chronic inflammatory disorder which remains the main cause of cardiovascular morbidity and mortality, with carotid atherosclerosis (CA) being a major cause of ischemic stroke. Epigenetic regulation plays a significant role in CA progression and stroke, yet the impact of circulating microRNA expression, associated with atherogenesis, has not been clearly defined. We included 81 patients with moderate-severe CA (mean age 67 ± 7 years, 53% male), 42% of whom had prior ipsilateral ischemic stroke (i.e., were symptomatic). A total of 24 miRs were identified and their plasma expression levels were measured. We observed that several microRNAs were up-regulated in stroke survivors, namely miR-200c-3p (30.6 vs. 29.7, p = 0.047), miR-106b-3p (31.01 vs. 30.25, p = 0.004), and miR-494-5p (39 vs. 33, p < 0.001), while others (miR183-3p [25.5 vs. 28.6, p < 0.001], miR-126-5p [35.6 vs. 37.1, p = 0.03], and miR-216-3p [12.34 vs. 16.2, p < 0.001]) had lower plasma levels in symptomatic patients. In a multivariable logistic regression model for symptomatic CA, the only miRs showing statistical significance were miR-106b-5p, miR-183-3p, miR-216-3p, and miR-494-5p. Cluster analysis demonstrated differential miR expression in CA patients depending on their stroke status. Epigenetic modulation, represented as complex interplay between circulating miRs of different atherogenic potential, may play a significant role in CA development and progression. In our study, we show possible candidates for future research regarding CA and stroke.

Non-coding RNAs as regulators of the Hippo pathway in cardiac development and cardiovascular disease

Cardiovascular diseases pose a serious threat to human health. The onset of cardiovascular diseases involves the comprehensive effects of multiple genes and environmental factors, and multiple signaling pathways are involved in regulating the occurrence and development of cardiovascular diseases. The Hippo pathway is a highly conserved signaling pathway involved in the regulation of cell proliferation, apoptosis, and differentiation. Recently, it has been widely studied in the fields of cardiovascular disease, cancer, and cell regeneration. Non-coding RNA (ncRNAs), which are important small molecules for the regulation of gene expression in cells, can directly target genes and have diverse regulatory functions. Recent studies have found that ncRNAs interact with Hippo pathway components to regulate myocardial fibrosis, cardiomyocyte proliferation, apoptosis, and hypertrophy and play an important role in cardiovascular disease. In this review, we describe the mode of action of ncRNAs in regulating the Hippo pathway, provide new ideas for further research, and identify molecules involved in the mechanism of action of ncRNAs and the Hippo pathway as potential therapeutic targets, with the aim of finding new modes of action for the treatment and prevention of cardiovascular diseases.

Effect of miR-663 on atherosclerosis by regulating the proliferation of vascular smooth muscle cells in lipid plaques

OBJECTIVES

Atherosclerosis (AS) is the main cause of coronary heart disease, cerebral infarction, and peripheral vascular disease. microRNAs (miRNAs) are widely distributed in the human body and closely related to the pathological progress of AS. This study probed into the function of miR-663 in AS.

METHODS

The atherosclerotic plaques, cholesterol (CHOL), low-density lipoprotein (LDL), inflammatory factors, and miR-663 expression in ApoE-/- mice on high-fat diet were evaluated. The overexpressing miR-663 adenovirus was injected into ApoE-/- mice, followed by measurement of type III collagen (Col III), matrix metalloproteinase (MMP)-2, α-SMA, osteopontin, and CD31. miR-663 mimic or inhibitor was introduced into vascular smooth muscle cells (VSMCs) stimulated by oxidized LDL (Ox-LDL), and cell proliferation and IL-6 and IL-18 secretion were evaluated. The binding relationship between miR-663 and HMGA2 was verified, followed by the determination of HMGA2 role in VSMC proliferation.

RESULTS

Atherosclerotic plaques appeared in ApoE-/- mice on high-fat diet, with increased CHOL, LDL, osteopontin, MMP-2 and Col III and decreased miR-663, α-SMA and CD31. miR-663 overexpression downregulated osteopontin, MMP-2 and Col III and upregulated α-SMA and CD31 in ApoE-/- mice on high-fat diet. With Ox-LDL concentration increase, VSMC proliferation was promoted and miR-663 was downregulated. miR-663 overexpression inhibited proliferation of Ox-LDL-stimulated VSMCs and reduced levels of inflammatory factor levels, whereas silencing miR-663 did the opposite. miR-663 targeted HMGA2. HMGA2 overexpression partially reversed the inhibitory effect of miR-663 overexpression on VSMC proliferation.

CONCLUSION

miR-663 targeted HMGA2 to inhibit VSMC proliferation and AS development, which may offer insights into AS treatment.

Regulation of cardiovascular calcification by lipids and lipoproteins

PURPOSE OF REVIEW

Lipids and lipoproteins have long been known to contribute to atherosclerosis and cardiovascular calcification. One theme of recent work is the study of lipoprotein (a) [Lp(a)], a lipoprotein particle similar to LDL-cholesterol that carries a long apoprotein tail and most of the circulating oxidized phospholipids.

RECENT FINDINGS

In-vitro studies show that Lp(a) stimulates osteoblastic differentiation and mineralization of vascular smooth muscle cells, while the association of Lp(a) with coronary artery calcification continues to have varying results, possibly because of the widely varying threshold levels of Lp(a) chosen for association analyses. Another emerging area in the field of cardiovascular calcification is pathological endothelial-to-mesenchymal transition (EndMT), the process whereby endothelial cell transition into multipotent mesenchymal cells, some of which differentiate into osteochondrogenic cells and mineralize. The effects of lipids and lipoproteins on EndMT suggest that they modulate cardiovascular calcification through multiple mechanisms. There are also emerging trends in imaging of calcific vasculopathy, including: intravascular optical coherence tomography for quantifying plaque characteristics, PET with a radiolabeled NaF tracer, with either CT or MRI to detect coronary plaque vulnerability.

SUMMARY

Recent work in this field includes studies of Lp(a), EndMT, and new imaging techniques.

Mechanisms of Oxidized LDL-Mediated Endothelial Dysfunction and Its Consequences for the Development of Atherosclerosis

Atherosclerosis is an immuno-metabolic disease involving chronic inflammation, oxidative stress, epigenetics, and metabolic dysfunction. There is compelling evidence suggesting numerous modifications including the change of the size, density, and biochemical properties in the low-density lipoprotein (LDL) within the vascular wall. These modifications of LDL, in addition to LDL transcytosis and retention, contribute to the initiation, development and clinical consequences of atherosclerosis. Among different atherogenic modifications of LDL, oxidation represents a primary modification. A series of pathophysiological changes caused by oxidized LDL (oxLDL) enhance the formation of foam cells and atherosclerotic plaques. OxLDL also promotes the development of fatty streaks and atherogenesis through induction of endothelial dysfunction, formation of foam cells, monocyte chemotaxis, proliferation and migration of SMCs, and platelet activation, which culminate in plaque instability and ultimately rupture. This article provides a concise review of the formation of oxLDL, enzymes mediating LDL oxidation, and the receptors and pro-atherogenic signaling pathways of oxLDL in vascular cells. The review also explores how oxLDL functions in different stages of endothelial dysfunction and atherosclerosis. Future targeted pathways and therapies aiming at reducing LDL oxidation and/or lowering oxLDL levels and oxLDL-mediated pro-inflammatory responses are also discussed.

YAP is critical to inflammation, endothelial-mesenchymal transition and subretinal fibrosis in experimental choroidal neovascularization

Subretinal fibrosis causes local damage to the retina and irreversible vision loss, as the final stage of neovascular age-related macular degeneration (nAMD). More recently, the endothelial-to-mesenchymal transition (EndoMT) has been considered one of the most significant sources of myofibroblasts in subretinal fibrosis, though the underpinning molecular mechanisms remain unclear. In this study, a series of experiments were performed to test the hypothesis that Yes-associated protein (YAP) may be involved in EndoMT and subretinal fibrosis. We demonstrated that transforming growth factor (TGF)-β2 stimulation induces YAP dephosphorylation (activated) and nuclear transcription in human umbilical vein endothelial cells (HUVECs) by increasing reactive oxygen species (ROS) levels. Moreover, TGF-β2-mediated EndoMT and proinflammatory cytokine production in HUVECs were reduced by ROS clearance or YAP knockdown. Furthermore, the severity of subretinal fibrosis was markedly relieved by intravitreal administration of a small interfering RNA targeting YAP in the mouse laser-induced choroidal neovascularization (CNV) model. Our findings provide novel insights into a previously unknown effect of YAP on the EndoMT process and reveal YAP as a potential target for suppressing CNV-related subretinal fibrosis and protect vision.

MicroRNA-200c-3p Negatively Regulates ATP2A2 and Promotes the Progression of Papillary Thyroid Carcinoma

microRNA-200c-3p (miR-200c-3p) has emerged as an important tumor growth regulator. However, its function in papillary thyroid carcinoma (PTC) is poorly understood. This study was conducted to investigate the role of miR-200c-3p in the progression of human PTC. The miR-200c-3p expression in human PTC tissues and cell lines was evaluated. The target relationship between miR-200c-3p and candidate genes was predicted through bioinformatic analysis and confirmed with a luciferase reporter assay. miRNA or gene expression was altered using transfection, and cell behavior was analyzed using CCK-8, wound healing, Transwell, and colony formation assays. The tumor-promoting effects of miR-200c-3p were evaluated by xenografting tumors with K1 cells in nude mice. The expression level of miR-200c-3p in human PTC tissues and cell lines markedly increased, and this increased expression was significantly associated with a worse overall survival. When inactivated, miR-200c-3p suppressed K1 cells’ malignant behaviors, including decreasing proliferation and attenuating colony formation, migration, and invasion. Its inactivation also attenuated the development of xenografted K1 cells in nude mice. The effects of miR-200c-3p mimics on promoting the malignant behaviors of PTC cells were remarkably reversed by the overexpression of ATP2A2, as a downstream target of miR-200c-3p. miR-200c-3p acts as an oncogenic gene and promotes the malignant biological behaviors of human PTC cells, thereby directly targeting ATP2A2. This regulated axis may be used as a potential therapy of PTC.