MicroRNA-133a impairs perfusion recovery after hindlimb ischemia in diabetic mice

Enrichment of miR-17-5p enhances the protective effects of EPC-EXs on vascular and skeletal muscle injury in a diabetic hind limb ischemia model

BACKGROUND/AIMS

Diabetes mellitus (DM) is highly susceptible to diabetic hind limb ischemia (DHI). MicroRNA (MiR)-17-5p is downregulated in DM and plays a key role in vascular protection. Endothelial progenitor cell (EPC)-released exosomes (EPC-EXs) contribute to vascular protection and ischemic tissue repair by transferring their contained miRs to target cells. Here, we investigated whether miR-17-5p-enriched EPC-EXs (EPC-EXs^miR-17-5p) had conspicuous effects on protecting vascular and skeletal muscle in DHI in vitro and in vivo.

METHODS

EPCs transfected with scrambled control or miR-17-5p mimics were used to generate EPC-EXs and EPC-EXs^miR-17-5p. Db/db mice were subjected to hind limb ischemia. After the surgery, EPC-EXs and EPC-EXs^miR-17-5p were injected into the gastrocnemius muscle of the hind limb once every 7 days for 3 weeks. Blood flow, microvessel density, capillary angiogenesis, gastrocnemius muscle weight, structure integrity, and apoptosis in the hind limb were assessed. Vascular endothelial cells (ECs) and myoblast cells (C2C12 cells) were subjected to hypoxia plus high glucose (HG) and cocultured with EPC-EXs and EPC-EXs^miR-17-5p. A bioinformatics assay was used to analyze the potential target gene of miR-17-5p, the levels of SPRED1, PI3K, phosphorylated Akt, cleaved caspase-9 and cleaved caspase-3 were measured, and a PI3K inhibitor (LY294002) was used for pathway analysis.

RESULTS

In the DHI mouse model, miR-17-5p was markedly decreased in hind limb vessels and muscle tissues, and infusion of EPC-EXs^miR-17-5p was more effective than EPC-EXs in increasing miR-17-5p levels, blood flow, microvessel density, and capillary angiogenesis, as well as in promoting muscle weight, force production and structural integrity while reducing apoptosis in gastrocnemius muscle. In Hypoxia plus HG-injured ECs and C2C12 cells, we found that EPC-EXs^miR-17-5p could deliver their carried miR-17-5p into target ECs and C2C12 cells and subsequently downregulate the target protein SPRED1 while increasing the levels of PI3K and phosphorylated Akt. EPC-EXs^miR-17-5p were more effective than EPC-EXs in decreasing apoptosis and necrosis while increasing viability, migration, and tube formation in Hypoxia plus HG-injured ECs and in decreasing apoptosis while increasing viability and myotube formation in C2C12 cells. These effects of EPC-EXs^miR-17-5p could be abolished by a PI3K inhibitor (LY294002).

CONCLUSION

Our results suggest that miR-17-5p promotes the beneficial effects of EPC-EXs on DHI by protecting vascular ECs and muscle cell functions.

The Role of miRNA in the Regulation of Angiogenesis in Ischemic Heart Disease

Despite continued improvements in primary prevention and treatment, ischemic heart disease (IHD) is the most common cause of mortality in both developing and developed countries. Promoting angiogenesis and reconstructing vascular network in ischemic myocardium are critical process of postischemic tissue repair. Effective strategies to promote survival and avoid apoptosis of endothelial cells in the ischemic myocardium can help to achieve long-term cardiac angiogenesis. Therefore, it is of great importance to investigate the molecular pathophysiology of angiogenesis in-depth and to find the key targets that promote angiogenesis. Recently years, many studies have found that microRNAs play important regulatory roles in almost all process of angiogenesis, including vascular sprouting, proliferation, survival and migration of vascular endothelial cells, recruitment of vascular progenitor cells, and control of angiopoietin expression. This review presents detailed information about the regulatory role of miRNAs in the angiogenesis of IHD in recent years, and provides new therapeutic ideas for the treatment of IHD.

Aberrant expression of miR-133a in endothelial cells inhibits angiogenesis by reducing pro-angiogenic but increasing anti-angiogenic gene expression

Angiogenesis is a multi-factorial physiological process deregulated in human diseases characterised by excessive or insufficient blood vessel formation. Emerging evidence highlights a novel role for microRNAs as regulators of angiogenesis. Previous studies addressing the effect of miR-133a expression in endothelial cells during blood vessel formation have reported conflicting results. Here, we have assessed the specific effect of mature miR-133a strands in angiogenesis and the expression of endothelial angiogenic genes. Transfection of miR-133a-3p or -5p mimics in primary human endothelial cells significantly inhibited proliferation, migration, and tubular morphogenesis of transfected cells. Screening of gene arrays related to angiogenic processes, and further validation by TaqMan qPCR, revealed that aberrant expression of miR-133a-3p led to a decrease in the expression of genes encoding pro-angiogenic molecules, whilst increasing those with anti-angiogenic functions. Ingenuity Pathway Analysis of a collection of genes differentially expressed in cells harbouring miR-133a-3p, predicted decreased cellular functions related to vasculature branching and cell cycle progression, underlining the inhibitory role of miR-133a-3p in angiogenic cellular processes. Our results suggest that controlled delivery of miR-133a-3p mimics, or antagomirs in diseased endothelial cells, might open new therapeutic interventions to treat patients suffering from cardiovascular pathologies that occur with excessive or insufficient angiogenesis.

miR-133a-A Potential Target for Improving Cardiac Mitochondrial Health and Regeneration After Injury

ABSTRACT

The various roles of muscle secretory factors and myokines have been well studied, but in recent decades, the role of myocyte-specific microRNAs (myomiRs) has gained momentum. These myomiRs are known to play regulatory roles in muscle health in general, both skeletal muscle and cardiac muscle. In this review, we have focused on the significance of a myomiR termed miR-133a in cardiovascular health. The available literature supports the claim that miR-133a could be helpful in the healing process of muscle tissue after injury. The protective function could be due to its regulatory effect on muscle or stem cell mitochondrial function. In this review, we have shed light on the protective mechanisms offered by miR-133a. Most of the beneficial effects are due to the presence of miR-133a in circulation or tissue-specific expression. We have also reviewed the potential mechanisms by which miR-133a could interact with cell surface receptors and also transcriptional mechanisms by which they offer cardioprotection and regeneration. Understanding these mechanisms will help in finding an ideal strategy to repair cardiac tissue after injury.

Cardiac Remodeling After Myocardial Infarction: Functional Contribution of microRNAs to Inflammation and Fibrosis

After an ischemic injury, the heart undergoes a complex process of structural and functional remodeling that involves several steps, including inflammatory and fibrotic responses. In this review, we are focusing on the contribution of microRNAs in the regulation of inflammation and fibrosis after myocardial infarction. We summarize the most updated studies exploring the interactions between microRNAs and key regulators of inflammation and fibroblast activation and we discuss the recent discoveries, including clinical applications, in these rapidly advancing fields.

Diabetes and Its Cardiovascular Complications: Comprehensive Network and Systematic Analyses

Diabetes mellitus is a worldwide health problem that usually comes with severe complications. There is no cure for diabetes yet and the threat of these complications is what keeps researchers investigating mechanisms and treatments for diabetes mellitus. Due to advancements in genomics, epigenomics, proteomics, and single-cell multiomics research, considerable progress has been made toward understanding the mechanisms of diabetes mellitus. In addition, investigation of the association between diabetes and other physiological systems revealed potentially novel pathways and targets involved in the initiation and progress of diabetes. This review focuses on current advancements in studying the mechanisms of diabetes by using genomic, epigenomic, proteomic, and single-cell multiomic analysis methods. It will also focus on recent findings pertaining to the relationship between diabetes and other biological processes, and new findings on the contribution of diabetes to several pathological conditions.

miR-548j-5p regulates angiogenesis in peripheral artery disease

Peripheral artery disease (PAD) is a vascular disease involving diffuse atherosclerosis, and is associated with increased cardiovascular mortality and morbidity. Critical limb ischemia (CLI) is the most severe complication of PAD. In addition to medical and interventional treatment, therapeutic angiogenesis is a novel therapy for PAD. Circulating microRNAs (miRNAs) are considered key regulators of gene expression, but their role in ischemic-induced angiogenesis is poorly-characterized. There is currently a limited understanding of the specific miRNAs associated with PAD. To determine the regulation of miRNAs, we obtained miRNA profiles using RNA isolated from patients with PAD and a control group. The effects of specific miRNAs on angiogenesis were evaluated by assessing the in vitro angiogenic function of endothelial progenitor cells (EPCs), performing an in vivo angiogenesis assay, and employing a mouse hindlimb ischemic model. Our results demonstrated that circulating miR-548j-5p was significantly reduced in patients with PAD as compared with the controls. miR-548j-5p promoted EPC angiogenesis by enhancing migration and tube formation. The endothelial nitric oxide synthase (NOS) and stromal cell-derived factor (SDF)-1 signaling pathways appeared to be potential targets of miR-548j-5p. Furthermore, the results of a directed in vivo angiogenesis assay of EPCs and a hindlimb ischemia mouse model demonstrated that miR-548j-5p enhanced the capillary density and blood flow recovery in hindlimb ischemia. In conclusion, our data indicated that up-regulation of miR-548j-5p promotes angiogenesis in ischemic tissue and may represent a novel therapeutic approach for PAD.

Current Knowledge of MicroRNAs (miRNAs) in Acute Coronary Syndrome (ACS): ST-Elevation Myocardial Infarction (STEMI)

Regardless of the newly diagnostic and therapeutic advances, coronary artery disease (CAD) and more explicitly, ST-elevation myocardial infarction (STEMI), remains one of the leading causes of morbidity and mortality worldwide. Thus, early and prompt diagnosis of cardiac dysfunction is pivotal in STEMI patients for a better prognosis and outcome. In recent years, microRNAs (miRNAs) gained attention as potential biomarkers in myocardial infarction (MI) and acute coronary syndromes (ACS), as they have key roles in heart development, various cardiac processes, and act as indicators of cardiac damage. In this review, we describe the current available knowledge about cardiac miRNAs and their functions, and focus mainly on their potential use as novel circulating diagnostic and prognostic biomarkers in STEMI.

GCH1-regulated miRNAs are potential targets for microglial activation in neuropathic pain

Neuropathic pain (NP) is a chronic pain directly caused by injury or disease of the somatosensory nervous system. Previous studies suggest that GTP cyclohydrolase I (GCH1) may play a pivotal role in microglial activation, which has been shown to be essential for NP. However, its underlying mechanisms in microglial activation remain unclear. A wide range of microRNAs (miRNAs) have been found to be involved in microglial activation-induced NP. To identify the miRNAs regulated by GCH1 and predict their functions in the progression of microglial activation, we analyzed the miRNA expression profiles of GCH1-knockdown (KD) BV2 microglial cells. Small RNA-sequencing analysis revealed 13 differentially expressed (DE) miRNAs in GCH1-KD cells. The target genes of DE miRNAs mainly participate in PI3K-Akt signaling pathway, peroxisome and ferroptosis. The miRNA–mRNA regulatory network analysis showed that GCH1, MAP4K5 and YWHAB acted as hub genes. qRT-PCR results further verified the expression levels of mmu-miR-1a-3p, mmu-miR-133a-3p, mmu-miR-7a-5p and mmu-miR-10a-5p in GCH1-KD cells, which were consistent with the sequencing data. In addition, our data indicated that overexpression of mmu-miR-133a-3p alleviated the pro-inflammatory cytokines IL-1β and IL-6 production induced by lipopolysaccharide (LPS), indicating that mmu-miR-133a-3p has a negative effect on microglial activation. Taken together, our findings suggest that many miRNAs regulated by GCH1 may be involved in microglial activation, which may provide new potential targets for GCH1 in the pathogenesis of NP.

The impact of proangiogenic microRNA modulation on blood flow recovery following hind limb ischemia. A systematic review and meta-analysis of animal studies

BACKGROUND

Pro-angiogenic microRNA modulation is a potentially attractive approach in the management of peripheral artery disease (PAD). The aim of this systematic review and meta-analysis was to examine the impact of microRNAs involved in the process of angiogenesis on blood flow recovery following hind limb ischemia induction in animal models.

METHODS

A literature search was performed to identify studies testing the efficacy of microRNA treatment on animal models of hind limb ischemia. Following that, a meta-analysis of the included studies was executed with the primary outcome being the change in ischemic-to-normal hind limb perfusion ratio assessed via laser Doppler imaging. Moreover, risk of bias, sensitivity analysis and publication bias were evaluated.

RESULTS

Studies evaluation led to the inclusion of 18 studies whose meta-analysis suggested that microRNA treatment resulted in improved ischemic hind limb perfusion 7 [standardized mean difference (SMD): 0.93, 95% CI 0.49-1.38], 14 (SMD: 1.31, 95% CI 0.78-1.84), and 21 days (SMD: 1.13, 95% CI 0.59-1.66) after hind limb ischemia induction. Moderate-to-substantial heterogeneity and possible publication bias were noted. Risk of bias was unclear despite the balanced baseline animal characteristics.

CONCLUSION

The present meta-analysis suggests that pro-angiogenic modulation of microRNAs accelerates vascular perfusion recovery in animal models of acute hind limb ischemia. Further studies on animal models with similar characteristics to that of PAD patients are warranted to translate those findings in human PAD setting.

miR-34a attenuates myocardial fibrosis in diabetic cardiomyopathy mice via targeting Pin-1

Diabetic cardiomyopathy (DCM) is characterized by myocardial hypertrophy and fibrosis. This study aimed to investigate the effects of microRNA (miR)-34a on myocardial fibrosis in DCM and its potential mechanism of targeting Pin-1 signaling. Vimentin and Pin-1 proteins in mouse cardiac tissues were detected by immunohistochemical staining. Locked nucleic acid in situ hybridization was used to measure miR-34a expression in cardiac tissues. Primary mouse cardiac fibroblasts (CFs) were transfected with a mimics control/miR-34a mimics or Pin-1 plasmid and cultured in high-glucose (HG) Dulbecco's modified Eagle's medium. The miR-34a levels were measured by quantitative polymerase chain reaction. The apoptosis and viability of transfected cells were detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling and Cell Counting Kit-8 assays respectively. A cell migration experiment and dual-luciferase reporter assay were also performed. The body weight and fasting blood glucose of DCM mice were significantly higher than those in the control (CTL) group. In addition, DCM mice had decreased serum insulin levels and impaired cardiac function. The number of CFs in the DCM group was higher than in the CTL group and Pin-1 expression was upregulated. The expression level of miR-34a in the cardiac tissue of mice in the DCM group was obviously downregulated compared with the CTL group. The HG stimulation of CFs for 48 h significantly downregulated the expression level of miR-34a and was associated with increased Type I collagen expression, cell viability, and migration and decreased apoptosis. However, these effects could be reversed by overexpressing miR-34a in HG-induced CFs. Furthermore, we found that Pin-1 was a direct target of miR-34a. Our results suggest that miR-34a can attenuate myocardial fibrosis in DCM by reducing Type I collagen production, cell viability, and migration and increasing the apoptosis of CFs by targeting Pin-1 signaling.

MicroRNA-210 improves perfusion recovery following hindlimb ischemia via suppressing reactive oxygen species

In peripheral arterial disease (PAD), angiogenesis is a major process involved in repairing the microvasculature in the ischemic lower limb. MicroRNA-210 (miR-210) is a microRNA that is substantially increased in patients with PAD. However, the effects of miR-210 on angiogenesis following PAD remain elusive. In the present study, mice with hindlimb ischemia (HLI) were generated as an animal model of PAD, and miR-210 levels were overexpressed in the ischemic limb. The overexpression of miR-210 using microRNA mimics greatly improved angiogenesis and perfusion recovery; in contrast, the knockdown of miR-210 impaired perfusion recovery 28 days after HLI. Ischemic muscle tissue was harvested 7 days after experimental PAD in order to perform biochemical tests, and miR-210 antagonism resulted in increased malondialdehyde levels. In cultured endothelial cells under simulated ischemia, miR-210 mimic improved endothelial cell viability and enhanced tube formation; and a miR-210 inhibitor decreased cell survival, reduced tube formation and increased reactive oxygen species (ROS) levels. Furthermore, miR-210 antagonism increased the protein disulfide-isomerase levels in cultured endothelial cells. These results demonstrate that ischemia-induced miR-210 elevation is adaptive in PAD, and that miR-210 improves angiogenesis at least partially through decreasing ROS production.

Trimethylamine N-oxide impairs perfusion recovery after hindlimb ischemia

BACKGROUND

The circulating level of trimethylamine N-oxide (TMAO) has been reported to be associated with the prognosis of of peripheral arterial disease (PAD) patients. However, the effects of TMAO on neovascularization and perfusion recovery after PAD are not known.

METHODS

Unilateral hindlimb ischemia was generated in mice as experimental PAD model, TMAO or 3,3-dimethyl-1-butanol (DMB) were added to the drinking water for these mice. In cultured endothelial cells, TMAO was added to culture medium to assess the effects on cell viability and tube formation under simulated ischemic conditions.

RESULTS

In experimental PAD, TMAO treatment increased malondialdehyde (MDA), interleukin (IL)-1β and IL-6 in the ischemic muscle, impaired perfusion recovery, and decreased capillary density. On the other hand, mice fed with DMB drinking water showed lower TMAO level, interleukin (IL)-1β and IL-6, and higher vascular endothelial growth factor in the ischemic muscle, and better perfusion recovery after experimental PAD. In cultured endothelial cell, TMAO decreased intracellular nitric oxide, cell viability and tube formation, and increased intracellular reactive oxygen species levels.

CONCLUSIONS

TMAO increases oxidative stress and inflammation, and impairs perfusion recovery and angiogenesis in experimental PAD.

Noncoding RNAs in Critical Limb Ischemia

Peripheral artery disease, caused by chronic arterial occlusion of the lower extremities, affects over 200 million people worldwide. Peripheral artery disease can progress into critical limb ischemia (CLI), its more severe manifestation, which is associated with higher risk of limb amputation and cardiovascular death. Aiming to improve tissue perfusion, therapeutic angiogenesis held promise to improve ischemic limbs using delivery of growth factors but has not successfully translated into benefits for patients. Moreover, accumulating studies suggest that impaired downstream signaling of these growth factors (or angiogenic resistance) may significantly contribute to CLI, particularly under harsh environments, such as diabetes mellitus. Noncoding RNAs are essential regulators of gene expression that control a range of pathophysiologies relevant to CLI, including angiogenesis/arteriogenesis, hypoxia, inflammation, stem/progenitor cells, and diabetes mellitus. In this review, we summarize the role of noncoding RNAs, including microRNAs and long noncoding RNAs, as functional mediators or biomarkers in the pathophysiology of CLI. A better understanding of these ncRNAs in CLI may provide opportunities for new targets in the prevention, diagnosis, and therapeutic management of this disabling disease state.

MicroRNA-133a and Myocardial Infarction

Myocardial infarction (MI) is the leading cause of morbidity and mortality in the world. The infarcted heart displays typical cell death cascades characterized by a loss of cells and fibrotic scarring in the myocardium. Cardiac hypertrophy and fibrosis largely contribute to ventricular wall thickening and stiffening, altogether defining an adverse cardiac remodeling that ultimately leads to impaired cardiac function and subsequent heart failure. Finding a strategy to promote therapeutic, instead of detrimental, cardiac remodeling may pose as a potent MI treatment. Accumulating evidence shows that microRNAs (miRNAs) may play an essential role in cardiovascular diseases. In particular, microRNA-133a (miR-133a) is one of the most abundant miRNAs in the heart. Multiple studies have demonstrated that miR-133a participates in the early pathology of MI, as well as in subsequent cardiac remodeling. In this review, we summarize recent research progress highlighting the regulatory effects of miR-133a in ischemic myocardial diseases, such as inhibiting angiogenesis, apoptosis, fibrosis, hypertrophy, and inflammation, while promoting therapeutic cardiac remodeling. The goal is to elicit a critical discussion on the translational direction of miRNA-mediated treatments towards a safe and effective MI therapy.

Involvement of Extracellular Vesicles in Vascular-Related Functions in Cancer Progression and Metastasis

The primary cause of mortality among patients with cancer is the progression of the tumor, better known as cancer invasion and metastasis. Cancer progression involves a series of biologically important steps in which the cross-talk between cancer cells and the cells in the surrounding environment is positioned as an important issue. Notably, angiogenesis is a key tumorigenic phenomenon for cancer progression. Cancer-related extracellular vesicles (EVs) commonly contribute to the modulation of a microenvironment favorable to cancer cells through their function of cell-to-cell communication. Vascular-related cells such as endothelial cells (ECs) and platelets activated by cancer cells and cancer-derived EVs develop procoagulant and proinflammatory statuses, which help excite the tumor environment, and play major roles in tumor progression, including in tumor extravasation, tumor cell microthrombi formation, platelet aggregation, and metastasis. In particular, cancer-derived EVs influence ECs, which then play multiple roles such as contributing to tumor angiogenesis, loss of endothelial vascular barrier by binding to ECs, and the subsequent endothelial-to-mesenchymal transition, i.e., extracellular matrix remodeling. Thus, cell-to-cell communication between cancer cells and ECs via EVs may be an important target for controlling cancer progression. This review describes the current knowledge regarding the involvement of EVs, especially exosomes derived from cancer cells, in EC-related cancer progression.

MicroRNA-15b participates in the development of peripheral arterial disease by modulating the growth of vascular smooth muscle cells

As an atherosclerotic disease, the process of peripheral arterial disease (PAD) is complicated and includes the abnormal proliferation of vascular smooth muscle. The current study aimed to determine the role of microRNA-15b (miR-15b) in the development of PAD and its associated mechanisms. Human vascular smooth muscle cells (hVSMCs) were used in the current study. To assess the effects of miR-15b on hVSMCs, miR-15b was up- or downregulated in hVSMCs using miR-15b mimics or miR-15b inhibitors respectively. Cell viability, migration and apoptosis were then determined via MTT, transwell and flow cytometry assays, respectively. TargetScan bioinformatics software was utilized to predict the targets of miR-15b, and the binding sites between insulin growth factor 1 receptor (IGF1R) and miR-15b were confirmed by dual-luciferase reporter assay. The results reveled that the miR-15b mimic significantly reduced hVSMC cell viability and migration, and promoted cell apoptosis. However, the opposite effect was observed following miR-15b inhibitor transfection. It was also determined that miR-15b directly targeted IGF1R and negatively regulated its expression in hVSMCs. Additionally, the results demonstrated that the miR-15b mimic inhibited the PI3K/AKT signaling pathway in hVSMCs, whereas the miR-15b inhibitor promoted it. Furthermore, the results indicated that the effect of the miR-15b mimic on hVSMCs was reversed by IGF1R overexpression. In conclusion, the data indicated that miR-15b participated in the occurrence and development of PAD by modulating hVSMC proliferation, apoptosis and migration via the regulation of IGF1R expression.