Long non-coding RNAs (lncRNAs) are emerging regulators of pathophysiological processes including atherosclerosis. Using RNA-seq profiling of the intima of lesions, here we identify a ...macrophage-specific lncRNA MAARS (Macrophage-Associated Atherosclerosis lncRNA Sequence). Aortic intima expression of MAARS increases by 270-fold with atherosclerotic progression and decreases with regression by 60%. MAARS knockdown reduces atherosclerotic lesion formation by 52% in LDLR
mice, largely independent of effects on lipid profile and inflammation, but rather by decreasing macrophage apoptosis and increasing efferocytosis in the vessel wall. MAARS interacts with HuR/ELAVL1, an RNA-binding protein and important regulator of apoptosis. Overexpression and knockdown studies verified MAARS as a critical regulator of macrophage apoptosis and efferocytosis in vitro, in an HuR-dependent manner. Mechanistically, MAARS knockdown alters HuR cytosolic shuttling, regulating HuR targets such as p53, p27, Caspase-9, and BCL2. These findings establish a mechanism by which a macrophage-specific lncRNA interacting with HuR regulates apoptosis, with implications for a broad range of vascular disease states.
Objective- In response to tissue injury, the appropriate progression of events in angiogenesis is controlled by a careful balance between pro and antiangiogenic factors. We aimed to identify and ...characterize microRNAs that regulate angiogenesis in response to tissue injury. Approach and Results- We show that in response to tissue injury, microRNA-615-5p (miR-615-5p) is rapidly induced and serves as an antiangiogenic microRNA by targeting endothelial cell VEGF (vascular endothelial growth factor)-AKT (protein kinase B)/eNOS (endothelial nitric oxide synthase) signaling in vitro and in vivo. MiR-615-5p expression is increased in wounds of diabetic db/db mice, in plasma of human subjects with acute coronary syndromes, and in plasma and skin of human subjects with diabetes mellitus. Ectopic expression of miR-615-5p markedly inhibited endothelial cell proliferation, migration, network tube formation in Matrigel, and the release of nitric oxide, whereas miR-615-5p neutralization had the opposite effects. Mechanistic studies using transcriptomic profiling, bioinformatics, 3' untranslated region reporter and microribonucleoprotein immunoprecipitation assays, and small interfering RNA dependency studies demonstrate that miR-615-5p inhibits the VEGF-AKT/eNOS signaling pathway in endothelial cells by targeting IGF2 (insulin-like growth factor 2) and RASSF2 (Ras-associating domain family member 2). Local delivery of miR-615-5p inhibitors, markedly increased angiogenesis, granulation tissue thickness, and wound closure rates in db/db mice, whereas miR-615-5p mimics impaired these effects. Systemic miR-615-5p neutralization improved skeletal muscle perfusion and angiogenesis after hindlimb ischemia in db/db mice. Finally, modulation of miR-615-5p expression dynamically regulated VEGF-induced AKT signaling and angiogenesis in human skin organoids as a model of tissue injury. Conclusions- These findings establish miR-615-5p as an inhibitor of VEGF-AKT/eNOS-mediated endothelial cell angiogenic responses and that manipulating miR-615-5p expression could provide a new target for angiogenic therapy in response to tissue injury. Visual Overview- An online visual overview is available for this article.
Cellular interactions in the tumor microenvironment influence neoplastic progression in pancreatic ductal adenocarcinoma. One underlying mechanism is the induction of the prognostically unfavorable ...epithelial–mesenchymal-transition-like tumor budding. Our aim is to explore the expression of microRNAs implicated in the regulation of tumor budding focusing on the microenvironment of the invasive front. To this end, RNA from laser-capture-microdissected material of the main tumor, tumor buds, juxta-tumoral stroma, tumor-remote stroma, and non-neoplastic pancreatic parenchyma from pancreatic cancer cases with (n=7) and without (n=6) tumor budding was analyzed by qRT-PCR for the expression of a panel of miRNAs that are known to be implicated in the regulation of epithelial–mesenchymal transition, including miR-21, miR-183, miR-200b, miR-200c, miR-203, miR-205, miR-210, and miR-217. Here we show that at the invasive front of pancreatic ductal adenocarcinoma, specific microRNAs, are differentially expressed between tumor buds and main tumor cells and between cases with and without tumor budding, indicating their involvement in the regulation of the budding phenotype. Notably, miR-200b and miR-200c were significantly downregulated in the tumor buds. Consistent with this finding, they negatively correlated with the expression of epithelial–mesenchymal-transition-associated E-cadherin repressors ZEB1 and ZEB2 in the budding cells (P<0.001). Interestingly, many microRNAs were also dysregulated in juxta-tumoral compared to tumor-remote stroma suggesting that juxta-tumoral stroma contributes to microRNA dysregulation. Notably, miR-200b and miR-200c were strongly downregulated while miR-210 and miR-21 were upregulated in the juxta-tumoral vs tumor-remote stroma in carcinomas with tumor budding. In conclusion, microRNA targeting in both tumor and stromal cells could represent a treatment option for aggressive pancreatic cancer.
Endothelial cell (EC) activation is an early hallmark in the pathogenesis of chronic vascular diseases. MicroRNA-181b (
) is an important anti-inflammatory mediator in the vascular endothelium ...affecting endotoxemia, atherosclerosis, and insulin resistance. Herein, we identify that the drug methotrexate (MTX) and its downstream metabolite adenosine exert anti-inflammatory effects in the vascular endothelium by targeting and activating
expression. Both systemic and endothelial-specific
-deficient mice develop vascular inflammation, white adipose tissue (WAT) inflammation, and insulin resistance in a diet-induced obesity model. Moreover, MTX attenuated diet-induced WAT inflammation, insulin resistance, and EC activation in a
-dependent manner. Mechanistically, MTX attenuated cytokine-induced EC activation through a unique adenosine-adenosine receptor A3-SMAD3/4-
signaling cascade. These findings establish an essential role of endothelial
in controlling vascular inflammation and that restoring
in ECs by high-dose MTX or adenosine signaling may provide a potential therapeutic opportunity for anti-inflammatory therapy.
Long noncoding RNAs (lncRNAs) play important roles in regulating diverse cellular processes in the vessel wall, including atherosclerosis. RNA-Seq profiling of intimal lesions revealed a lncRNA, ...VINAS (Vascular INflammation and Atherosclerosis lncRNA Sequence), that is enriched in the aortic intima and regulates vascular inflammation. Aortic intimal expression of VINAS fell with atherosclerotic progression and rose with regression. VINAS knockdown reduced atherosclerotic lesion formation by 55% in LDL receptor-deficient (LDLR-/-) mice, independent of effects on circulating lipids, by decreasing inflammation in the vessel wall. Loss- and gain-of-function studies in vitro demonstrated that VINAS serves as a critical regulator of inflammation by modulating NF-κB and MAPK signaling pathways. VINAS knockdown decreased the expression of key inflammatory markers, such as MCP-1, TNF-α, IL-1β, and COX-2, in endothelial cells (ECs), vascular smooth muscle cells, and bone marrow-derived macrophages. Moreover, VINAS silencing decreased expression of leukocyte adhesion molecules VCAM-1, E-selectin, and ICAM-1 and reduced monocyte adhesion to ECs. DEP domain containing 4 (DEPDC4), an evolutionary conserved human ortholog of VINAS with approximately 74% homology, showed similar regulation in human and pig atherosclerotic specimens. DEPDC4 knockdown replicated antiinflammatory effects of VINAS in human ECs. These findings reveal a potentially novel lncRNA that regulates vascular inflammation, with broad implications for vascular diseases.
Less than 2% of the genome encodes for proteins. Accumulating studies have revealed a diverse set of RNAs derived from the non-coding genome. Among them, long non-coding RNAs (lncRNAs) have garnered ...widespread attention over recent years as emerging regulators of diverse biological processes including in cardiovascular disease (CVD). However, our knowledge of their mechanisms by which they control CVD-related gene expression and cell signaling pathways is still limited. Furthermore, only a handful of lncRNAs has been functionally evaluated in the context of vascular inflammation, an important process that underlies both acute and chronic disease states. Because some lncRNAs may be expressed in cell- and tissue-specific expression patterns, these non-coding RNAs hold great promise as novel biomarkers and as therapeutic targets in health and disease. Herein, we review those lncRNAs implicated in pro- and anti-inflammatory processes of acute and chronic vascular inflammation. An improved understanding of lncRNAs in vascular inflammation may provide new pathophysiological insights in CVD and opportunities for the generation of a new class of RNA-based biomarkers and therapeutic targets.
Accumulating studies indicate that long non-coding RNAs (lncRNAs) play important roles in the regulation of diverse biological processes involved in homeostatic control of the vessel wall in health ...and disease. However, our knowledge of the mechanisms by which lncRNAs control gene expression and cell signaling pathways is still nascent. Furthermore, only a handful of lncRNAs has been functionally evaluated in response to pathophysiological stimuli or in vascular disease states. For example, lncRNAs may regulate endothelial dysfunction by modulating endothelial cell proliferation (e.g. MALAT1, H19) or angiogenesis (e.g. MEG3, MANTIS). LncRNAs have also been implicated in modulating vascular smooth muscle cell (VSMC) phenotypes or vascular remodeling (e.g. ANRIL, SMILR, SENCR, MYOSLID). Finally, emerging studies have implicated lncRNAs in leukocytes activation (e.g. lincRNA-Cox2, linc00305, THRIL), macrophage polarization (e.g. GAS5), and cholesterol metabolism (e.g. LeXis). This review summarizes recent findings on the expression, mechanism, and function of lncRNAs implicated in a range of vascular disease states from mice to human subjects. An improved understanding of lncRNAs in vascular disease may provide new pathophysiological insights and opportunities for the generation of a new class of RNA-based biomarkers and therapeutic targets.
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