MicroRNAs in vascular tissue engineering and post-ischemic neovascularization

Potential application of let-7a antagomir in injured peripheral nerve regeneration

Neurotrophic factors, particularly nerve growth factor, enhance neuronal regeneration. However, the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages, such as its short biological half-life, its contribution to pain response, and its inability to cross the blood-brain barrier. Considering that let-7 (human miRNA) targets and regulates nerve growth factor, and that let-7 is a core regulator in peripheral nerve regeneration, we evaluated the possibilities of let-7 application in nerve repair. In this study, anti-let-7a was identified as the most suitable let-7 family molecule by analyses of endogenous expression and regulatory relationship, and functional screening. Let-7a antagomir demonstrated biosafety based on the results of in vivo safety assessments and it entered into the main cell types of the sciatic nerve, including Schwann cells, fibroblasts and macrophages. Use of hydrogel effectively achieved controlled, localized, and sustained delivery of let-7a antagomir. Finally, let-7a antagomir was integrated into chitosan conduit to construct a chitosan-hydrogel scaffold tissue-engineered nerve graft, which promoted nerve regeneration and functional recovery in a rat model of sciatic nerve transection. Our study provides an experimental basis for potential in vivo application of let-7a.

CDK14/β-catenin/TCF4/miR-26b positive feedback regulation modulating pancreatic cancer cell phenotypes in vitro and tumor growth in mice model in vivo

INTRODUCTION

Chemotherapy and radiotherapy have been reported to be basically ineffective for pancreatic ductal adenocarcinoma patients; thus, gene therapy might provide a novel approach. CDK14, a new oncogenic member of the CDK family involved in the pancreatic cancer cell response to gemcitabine treatment, has been reported to be regulated by microRNAs. In the present study, we aimed to investigate whether miR-26b regulated CDK14 expression to affect the phenotype of pancreatic cancer cells.

METHODS

Overexpression or knockdown of CDK14 or miR-26b was generated in pancreatic cancer cell lines and the function of CDK14 and miR-26b on cell phenotype and the Wnt signaling pathway was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-ethynyl-2'-deoxyuridine and transwell assays, as well as a xenograft model and western blotting. The predicted binding site between the 3'-untranslated region of CDK14 and miR-26b, miR-26b promoter and TCF4 was verified by luciferase or chromatin immunoprecipitation assays.

RESULTS

CDK14 overexpression inhibited p-GSK3β, whereas it promoted p-LRP6, the nuclear translocation of β-catenin and the transactivation of TCF4 transcription factor, thus promoting pancreatic cancer cell aggressiveness. miR-26b directly targeted CDK14 and inhibited CDK14 expression. In vitro and in vivo, miR-26b overexpression inhibited, and CDK14 overexpression promoted, cancer cell aggressiveness; CDK14 overexpression partially attenuated the miR-26b overexpression effects on cancer cells. The effects of miR-26b overexpression on tumor growth and the Wnt/β-catenin/TCF4 signaling were partially reversed by CDK14 overexpression. TCF4 inhibited the expression of miR-26b by targeting its promoter region.

CONCLUSIONS

CDK14, β-catenin, TCF4 and miR-26b form a positive feedback regulation for modulating pancreatic cancer cell phenotypes in vitro and tumor growth in vivo.

MicroRNA Sequencing Analysis in Obstructive Sleep Apnea and Depression: Anti-Oxidant and MAOA-Inhibiting Effects of miR-15b-5p and miR-92b-3p through Targeting PTGS1-NF-κB-SP1 Signaling

The aim of this study was to identify novel microRNAs related to obstructive sleep apnea (OSA) characterized by intermittent hypoxia with re-oxygenation (IHR) injury. Illumina MiSeq was used to identify OSA-associated microRNAs, which were validated in an independent cohort. The interaction between candidate microRNA and target genes was detected in the human THP-1, HUVEC, and SH-SY5Y cell lines. Next-generation sequencing analysis identified 22 differentially expressed miRs (12 up-regulated and 10 down-regulated) in OSA patients. Enriched predicted target pathways included senescence, adherens junction, and AGE-RAGE/TNF-α/HIF-1α signaling. In the validation cohort, miR-92b-3p and miR-15b-5p gene expressions were decreased in OSA patients, and negatively correlated with an apnea hypopnea index. PTGS1 (COX1) gene expression was increased in OSA patients, especially in those with depression. Transfection with miR-15b-5p/miR-92b-3p mimic in vitro reversed IHR-induced early apoptosis, reactive oxygen species production, MAOA hyperactivity, and up-regulations of their predicted target genes, including PTGS1, ADRB1, GABRB2, GARG1, LEP, TNFSF13B, VEGFA, and CXCL5. The luciferase assay revealed the suppressed PTGS1 expression by miR-92b-3p. Down-regulated miR-15b-5p/miR-92b-3p in OSA patients could contribute to IHR-induced oxidative stress and MAOA hyperactivity through the eicosanoid inflammatory pathway via directly targeting PTGS1-NF-κB-SP1 signaling. Over-expression of the miR-15b-5p/miR-92b-3p may be a new therapeutic strategy for OSA-related depression.

Vascular Tissue Specific miRNA Profiles Reveal Novel Correlations with Risk Factors in Coronary Artery Disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Non-coding RNAs have already been linked to CVD development and progression. While microRNAs (miRs) have been well studied in blood samples, there is little data on tissue-specific miRs in cardiovascular relevant tissues and their relation to cardiovascular risk factors. Tissue-specific miRs derived from Arteria mammaria interna (IMA) from 192 coronary artery disease (CAD) patients undergoing coronary artery bypass grafting (CABG) were analyzed. The aims of the study were 1) to establish a reference atlas which can be utilized for identification of novel diagnostic biomarkers and potential therapeutic targets, and 2) to relate these miRs to cardiovascular risk factors. Overall, 393 individual miRs showed sufficient expression levels and passed quality control for further analysis. We identified 17 miRs-miR-10b-3p, miR-10-5p, miR-17-3p, miR-21-5p, miR-151a-5p, miR-181a-5p, miR-185-5p, miR-194-5p, miR-199a-3p, miR-199b-3p, miR-212-3p, miR-363-3p, miR-548d-5p, miR-744-5p, miR-3117-3p, miR-5683 and miR-5701-significantly correlated with cardiovascular risk factors (correlation coefficient >0.2 in both directions, p-value (p < 0.006, false discovery rate (FDR) <0.05). Of particular interest, miR-5701 was positively correlated with hypertension, hypercholesterolemia, and diabetes. In addition, we found that miR-629-5p and miR-98-5p were significantly correlated with acute myocardial infarction. We provide a first atlas of miR profiles in IMA samples from CAD patients. In perspective, these miRs might play an important role in improved risk assessment, mechanistic disease understanding and local therapy of CAD.

Coadministration of endothelial and smooth muscle cells derived from human induced pluripotent stem cells as a therapy for critical limb ischemia

Critical limb ischemia is a condition in which tissue necrosis occurs due to arterial occlusion, resulting in limb amputation in severe cases. Both endothelial cells (ECs) and vascular smooth muscle cells (SMCs) are needed for the regeneration of peripheral arteries in ischemic tissues. However, it is difficult to isolate and cultivate primary EC and SMC from patients for therapeutic angiogenesis. Induced pluripotent stem cells (iPSCs) are regarded as useful stem cells due to their pluripotent differentiation potential. In this study, we explored the therapeutic efficacy of human iPSC‐derived EC and iPSC‐derived SMC in peripheral artery disease model. After the induction of mesodermal differentiation of iPSC, CD34⁺ progenitor cells were isolated by magnetic‐activated cell sorting. Cultivation of the CD34⁺ progenitor cells in endothelial culture medium induced the expression of endothelial markers and phenotypes. Moreover, the CD34⁺ cells could be differentiated into SMC by cultivation in SMC culture medium. In a murine hindlimb ischemia model, cotransplantation of EC with SMC improved blood perfusion and increased the limb salvage rate in ischemic limbs compared to transplantation of either EC or SMC alone. Moreover, cotransplantation of EC and SMC stimulated angiogenesis and led to the formation of capillaries and arteries/arterioles in vivo. Conditioned medium derived from SMC stimulated the migration, proliferation, and tubulation of EC in vitro, and these effects were recapitulated by exosomes isolated from the SMC‐conditioned medium. Together, these results suggest that iPSC‐derived SMC enhance the therapeutic efficacy of iPSC‐derived EC in peripheral artery disease via an exosome‐mediated paracrine mechanism.

Functional analysis of down-regulated miRNA-221-5p in HeLa cell treated with polyphenol-rich Polyalthia longifolia as regulators of apoptotic HeLa cell death

MicroRNAs are endogenous small non-coding-RNAs that control gene expression and cancer development. Previous studies reported that Polyalthia longifolia treatment induced apoptotic cell death in HeLa cells by down-regulation of miR-221-5p. Hence, the current study was conducted to validate the down-regulated miR-221-5p in HeLa cells. Functional analysis of miR-221-5p was conducted through the gain-of-function, and loss-of-function approach and the miRNA expression was quantified by a real-time polymerase chain reaction. The P. longifolia treatment significantly (p < 0.05) reduced miR-221-5p expression when compared to the untreated HeLa cells with a double delta Ct value of 6.32 and the expression fold change value was reduced up to 0.013. The transfection of miR-221-5p mimic significantly increased the expression of miR-221-5p with an expression fold change as high as 0.53 while anti-miR-221-5p transfected HeLa cells show the most significant decrease in miR-221-5p expression with an expression fold change of 0.011. The MTT assay results revealed that the over-expression of miR-221-5p increased the cell proliferation and viability of polyphenol-rich P. longifolia-treated HeLa cells and confirmed the role of downregulated miRNA 221-5p in HeLa cell death. The flow-cytometry analysis showed that the miR-221-5p over-expressed cells decreased the apoptosis of cells induced by polyphenol-rich P. longifolia treatment in HeLa cells, which proved the oncogenic role of miR-221-5p to inhibit apoptosis. Moreover, the depletion of caspase-3 in miR-221-5p-overexpressed HeLa cells showed the roles of downregulated miR-221-5p in the induction of apoptosis. In conclusion, these results suggest that the down-regulated miR-221-5p was involved in regulating apoptosis in HeLa cancer cells.

MicroRNA-135a-3p regulates angiogenesis and tissue repair by targeting p38 signaling in endothelial cells

Angiogenesis is a critical process in repair of tissue injury that is regulated by a delicate balance between pro- and antiangiogenic factors. In disease states associated with impaired angiogenesis, we identified that miR-135a-3p is rapidly induced and serves as an antiangiogenic microRNA (miRNA) by targeting endothelial cell (EC) p38 signaling in vitro and in vivo. MiR-135a-3p overexpression significantly inhibited EC proliferation, migration, and network tube formation in matrigel, whereas miR-135-3p neutralization had the opposite effects. Mechanistic studies using transcriptomic profiling, bioinformatics, 3'-UTR reporter and miRNA ribonucleoprotein complex -immunoprecipitation assays, and small interfering RNA dependency studies revealed that miR-135a-3p inhibits the p38 signaling pathway in ECs by targeting huntingtin-interacting protein 1 (HIP1). Local delivery of miR-135a-3p inhibitors to wounds of diabetic db/db mice markedly increased angiogenesis, granulation tissue thickness, and wound closure rates, whereas local delivery of miR-135a-3p mimics impaired these effects. Finally, through gain- and loss-of-function studies in human skin organoids as a model of tissue injury, we demonstrated that miR-135a-3p potently modulated p38 signaling and angiogenesis in response to VEGF stimulation by targeting HIP1. These findings establish miR-135a-3p as a pivotal regulator of pathophysiological angiogenesis and tissue repair by targeting a VEGF-HIP1-p38K signaling axis, providing new targets for angiogenic therapy to promote tissue repair.-Icli, B., Wu, W., Ozdemir, D., Li, H., Haemmig, S., Liu, X., Giatsidis, G., Cheng, H. S., Avci, S. N., Kurt, M., Lee, N., Guimaraes, R. B., Manica, A., Marchini, J. F., Rynning, S. E., Risnes, I., Hollan, I., Croce, K., Orgill, D. P., Feinberg, M. W. MicroRNA-135a-3p regulates angiogenesis and tissue repair by targeting p38 signaling in endothelial cells.

Association study of miR-146a, miR-149, miR-196a2, and miR-499 polymorphisms with venous thromboembolism in a Korean population

Despite much progress in microRNA (miRNA) research, information regarding the association between miRNAs and venous thromboembolism (VTE), especially in Asian patients, remains limited. This case-control study sought to determine the correlation between the presence of polymorphisms in the genes encoding the miRNAs miR-146a, miR-149, miR-196a2, miR-499, and VTE in Korean patients. We observed no statistically significant differences in the genotype frequency of miRNA polymorphisms between 300 control individuals and 203 VTE patients. However, we observed a significant association between three allelic combinations of miRNA polymorphisms and VTE risk. Overall, our findings suggest that specific miRNA polymorphisms are associated with the risk of VTE in a Korean population.

Recent advances and challenges on application of tissue engineering for treatment of congenital heart disease

Congenital heart disease (CHD) affects a considerable number of children and adults worldwide. This implicates not only developmental disorders, high mortality, and reduced quality of life but also, high costs for the healthcare systems. CHD refers to a variety of heart and vascular malformations which could be very challenging to reconstruct the malformed region surgically, especially when the patient is an infant or a child. Advanced technology and research have offered a better mechanistic insight on the impact of CHD in the heart and vascular system of infants, children, and adults and identified potential therapeutic solutions. Many artificial materials and devices have been used for cardiovascular surgery. Surgeons and the medical industry created and evolved the ball valves to the carbon-based leaflet valves and introduced bioprosthesis as an alternative. However, with research further progressing, contracting tissue has been developed in laboratories and tissue engineering (TE) could represent a revolutionary answer for CHD surgery. Development of engineered tissue for cardiac and aortic reconstruction for developing bodies of infants and children can be very challenging. Nevertheless, using acellular scaffolds, allograft, xenografts, and autografts is already very common. Seeding of cells on surface and within scaffold is a key challenging factor for use of the above. The use of different types of stem cells has been investigated and proven to be suitable for tissue engineering. They are the most promising source of cells for heart reconstruction in a developing body, even for adults. Some stem cell types are more effective than others, with some disadvantages which may be eliminated in the future.

The dynamic changes of main cell types in the microenvironment of sciatic nerves following sciatic nerve injury and the influence of let-7 on their distribution

Schwann cells (SCs), fibroblasts and macrophages are the main cells in the peripheral nerve stumps.

miR-216a inhibits osteosarcoma cell proliferation, invasion and metastasis by targeting CDK14

Osteosarcoma (OS) has emerged as the most common primary musculoskeletal malignant tumour affecting children and young adults. Cyclin-dependent kinases (CDKs) are closely associated with gene regulation in tumour biology. Accumulating evidence indicates that the aberrant function of CDK14 is involved in a broad spectrum of diseases and is associated with clinical outcomes. MicroRNAs (miRNAs) are crucial epigenetic regulators in the development of OS. However, the essential role of CDK14 and the molecular mechanisms by which miRNAs regulate CDK14 in the oncogenesis and progression of OS have not been fully elucidated. Here we found that CDK14 expression was closely associated with poor prognosis and overall survival of OS patients. Using dual-luciferase reporter assays, we also found that miR-216a inhibits CDK14 expression by binding to the 3′-untranslated region of CDK14. Overexpression of miR-216a significantly suppressed cell proliferation, migration and invasion in vivo and in vitro by inhibiting CDK14 production. Overexpression of CDK14 in the miR-216a-transfected OS cells effectively rescued the suppression of cell proliferation, migration and invasion caused by miR-216a. In addition, Kaplan–Meier analysis indicated that miR-216a expression predicted favourable clinical outcomes for OS patients. Moreover, miR-216a expression was downregulated in OS patients and was negatively associated with CDK14 expression. Overall, these data highlight the role of the miR-216a/CDK14 axis as a novel pleiotropic modulator and demonstrate the associated molecular mechanisms, thus suggesting the intriguing possibility that miR-216a activation and CDK14 inhibition may be novel and attractive therapeutic strategies for treating OS patients.

CAGW Peptide- and PEG-Modified Gene Carrier for Selective Gene Delivery and Promotion of Angiogenesis in HUVECs in Vivo

Gene therapy is a promising strategy for angiogenesis, but developing gene carriers with low cytotoxicity and high gene delivery efficiency in vivo is a key issue. In the present study, we synthesized the CAGW peptide- and poly(ethylene glycol) (PEG)-modified amphiphilic copolymers. CAGW peptide serves as a targeting ligand for endothelial cells (ECs). Different amounts of CAGW peptide were effectively conjugated to the amphiphilic copolymer via heterofunctional poly(ethylene glycol). These CAG- and PEG-modified copolymers could form nanoparticles (NPs) by self-assembly method and were used as gene carriers for the pEGFP-ZNF580 (pZNF580) plasmid. CAGW and PEG modification coordinately improved the hemocompatibility and cytocompatibility of NPs. The results of cellular uptake showed significantly enhanced internalization efficiency of pZNF580 after CAGW modification. Gene expression at mRNA and protein levels demonstrated that EC-targeted NPs possessed high gene delivery efficiency, especially the NPs with higher content of CAGW peptide (1.16 wt %). Furthermore, in vitro and in vivo vascularization assays also showed outstanding vascularization ability of human umbilical vein endothelial cells treated by the NP/pZNF580 complexes. This study demonstrates that the CAGW peptide-modified NP is a promising candidate for gene therapy in angiogenesis.

Modulating microRNAs in cardiac surgery patients: Novel therapeutic opportunities?

This review focuses on microRNAs (miRs) in cardiac surgery, where they are emerging as potential targets for therapeutic intervention as well as novel clinical biomarkers. Identification of the up/down-regulation of specific miRs in defined groups of cardiac surgery patients can lead to the development of novel strategies for targeted treatment in order to maximise therapeutic results and minimise acute, delayed or chronic complications. MiRs could also be involved in determining the outcome independently of complications, for example in relation to myocardial perfusion and fibrosis. Because of their relevance in disease, their known sequence and pharmacological properties, miRs are attractive candidates for therapeutic manipulation. Pharmacological inhibition of individual miRs can be achieved by modified antisense oligonucleotides, referred to as antimiRs, while miR replacement can be achieved by miR mimics to increase the level of a specific miR. MiR mimics can restore the function of a lost or down-regulated miR, while antimiRs can inhibit the levels of disease-driving or aberrantly expressed miRs, thus de-repressing the expression of mRNAs targeted by the miR. The main delivery methods for miR therapeutics involve lipid-based vehicles, viral systems, cationic polymers, and intravenous or local injection of an antagomiR. Local delivery is particularly desirable for miR therapeutics and options include the development of devices specific for local delivery, light-induced antimiR, and vesicle-encapsulated miRs serving as therapeutic delivery agents able to improve intracellular uptake. Here, we discuss the potential therapeutic use of miRNAs in the context of cardiac surgery.

Guidelines for the functional annotation of microRNAs using the Gene Ontology

MicroRNA regulation of developmental and cellular processes is a relatively new field of study, and the available research data have not been organized to enable its inclusion in pathway and network analysis tools. The association of gene products with terms from the Gene Ontology is an effective method to analyze functional data, but until recently there has been no substantial effort dedicated to applying Gene Ontology terms to microRNAs. Consequently, when performing functional analysis of microRNA data sets, researchers have had to rely instead on the functional annotations associated with the genes encoding microRNA targets. In consultation with experts in the field of microRNA research, we have created comprehensive recommendations for the Gene Ontology curation of microRNAs. This curation manual will enable provision of a high-quality, reliable set of functional annotations for the advancement of microRNA research. Here we describe the key aspects of the work, including development of the Gene Ontology to represent this data, standards for describing the data, and guidelines to support curators making these annotations. The full microRNA curation guidelines are available on the GO Consortium wiki (http://wiki.geneontology.org/index.php/MicroRNA_GO_annotation_manual).

Micro-RNAs in abdominal aortic aneurysms: insights from animal models and relevance to human disease

Abdominal aortic aneurysm (AAA) is a major health concern and may be associated with high rates of mortality linked to acute complications. Diagnosis and treatment are, respectively, based on imaging and surgical techniques. Drug-based therapies are still mostly ineffective, which highlight a real unmet need. Major pathophysiological mechanisms leading to aneurysm formation involve inflammatory processes, degradation of the extracellular matrix, and loss of smooth muscle cells. However, the precise cellular and molecular pathways are still poorly understood. Recently, microRNAs have emerged as major intracellular players in a wide range of biological processes, and their stability in extracellular medium within microvesicles has led to propose them as mediators of intercellular crosstalk and as potential biomarkers and therapeutic targets in a variety of disease settings. To date, several studies have been performed to address the involvement of micro-RNAs (miRs) in aneurysm formation and complications. Here, we discuss the roles and implications of miRs in animal models and their relevance to human AAA.

Tissue engineering the cardiac microenvironment: Multicellular microphysiological systems for drug screening

The ability to accurately detect cardiotoxicity has become increasingly important in the development of new drugs. Since the advent of human pluripotent stem cell-derived cardiomyocytes, researchers have explored their use in creating an in vitro drug screening platform. Recently, there has been increasing interest in creating 3D microphysiological models of the heart as a tool to detect cardiotoxic compounds. By recapitulating the complex microenvironment that exists in the native heart, cardiac microphysiological systems have the potential to provide a more accurate pharmacological response compared to current standards in preclinical drug screening. This review aims to provide an overview on the progress made in creating advanced models of the human heart, including the significance and contributions of the various cellular and extracellular components to cardiac function.

MicroRNAs in liver tissue engineering - New promises for failing organs

miRNA-based technologies provide attractive tools for several liver tissue engineering approaches. Herein, we review the current state of miRNA applications in liver tissue engineering. Several miRNAs have been implicated in hepatic disease and proper hepatocyte function. However, the clinical translation of these findings into tissue engineering has just begun. miRNAs have been successfully used to induce proliferation of mature hepatocytes and improve the differentiation of hepatic precursor cells. Nonetheless, miRNA-based approaches beyond cell generation have not yet entered preclinical or clinical investigations. Moreover, miRNA-based concepts for the biliary tree have yet to be developed. Further research on miRNA based modifications, however, holds the promise of enabling significant improvements to liver tissue engineering approaches due to their ability to regulate and fine-tune all biological processes relevant to hepatic tissue engineering, such as proliferation, differentiation, growth, and cell function.