Therapeutic manipulation of angiogenesis with miR-27b

Intranasal delivery of small extracellular vesicles from specific subpopulation of mesenchymal stem cells mitigates traumatic spinal cord injury

Vascular injury following spinal cord injury (SCI) can significantly exacerbate secondary SCI and result in neurological dysfunction. Strategies targeting angiogenesis have demonstrated potential in enhancing functional recovery post-SCI. In the context of angiogenesis, the CD146+ and CD271+ subpopulations of mesenchymal stem cells (MSCs) have been recognized for their angiogenic capabilities in tissue repair. Small extracellular vesicles (sEVs) derived from MSCs are nanoscale vesicles containing rich bioactive components that play a crucial role in tissue regeneration. However, the precise role of sEVs derived from CD146+CD271+ UCMSCs (CD146+CD271+ UCMSC-sEVs) in SCI remain unclear. In this study, CD146+CD271+ UCMSC-sEVs were non-invasively administered via intranasal delivery, demonstrating a significant capacity to stimulate angiogenesis and improve functional recovery in mice following SCI. Furthermore, in vitro assessments revealed the effective enhancement of migration and tube formation capabilities of the murine brain microvascular endothelial cell line (bEnd.3) by CD146+CD271+UCMSC-sEVs. MicroRNA array analysis confirmed significant enrichment of multiple microRNAs within CD146+CD271+ UCMSC-sEVs. Subsequent in vivo and in vitro experiments demonstrated that CD146+CD271+ UCMSC-sEVs promote enhanced angiogenesis and improved functional recovery mediated by miR-27a-3p. Further mechanistic studies revealed that miR-27a-3p sourced from CD146+CD271+ UCMSC-sEVs enhances migration and tube formation of bEnd.3 cells in vitro by suppressing the expression of Delta Like Canonical Notch Ligand 4 (DLL4), thereby promoting angiogenesis in vivo. Collectively, our results demonstrate that a crucial role of CD146+CD271+ UCMSC-sEVs in inhibiting DLL4 through the transfer of miR-27a-3p, which leads to the promotion of angiogenesis and improved functional recovery after SCI.

Role of Angiogenesis and Its Biomarkers in Development of Targeted Tumor Therapies

Angiogenesis plays a significant role in the human body, from wound healing to tumor progression. "Angiogenic switch" indicates a time-restricted event where the imbalance between pro- and antiangiogenic factors results in the transition from prevascular hyperplasia to outgrowing vascularized tumor, which eventually leads to the malignant cancer progression. In the last decade, molecular players, i.e., angiogenic biomarkers and underlying molecular pathways involved in tumorigenesis, have been intensely investigated. Disrupting the initiation and halting the progression of angiogenesis by targeting these biomarkers and molecular pathways has been considered as a potential treatment approach for tumor angiogenesis. This review discusses the currently known biomarkers and available antiangiogenic therapies in cancer, i.e., monoclonal antibodies, aptamers, small molecular inhibitors, miRNAs, siRNAs, angiostatin, endostatin, and melatonin analogues, either approved by the U.S. Food and Drug Administration or currently under clinical and preclinical investigations.

A cellular regulator of the niche: telocyte

Interstitial cells are present in the environment of stem cells in order to increase stem cell proliferation and differentiation and they are important to increase the efficiency of their transplantation. Telocytes (TCs) play an important role both in the preservation of tissue organ integrity and in the pathophysiology of many diseases, especially cancer. They make homo- or heterocellular contacts to form the structure of 3D network through their telopodes and deliver signaling molecules via a juxtacrine and/or paracrine association by budding shed vesicles into the vascular, nervous and endocrine systems. During this interaction, along with organelles, mRNA, microRNA, long non-coding RNA, and genomic DNA are transferred. This review article not only specifies the properties of TCs and their roles in the tissue organ microenvironment but also gives information about the factors that play a role in the transport of epigenetic information by TCs.

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.

The various role of microRNAs in breast cancer angiogenesis, with a special focus on novel miRNA-based delivery strategies

After skin malignancy, breast cancer is the most widely recognized cancer detected in women in the United States. Breast cancer (BCa) can happen in all kinds of people, but it's much more common in women. One in four cases of cancer and one in six deaths due to cancer are related to breast cancer. Angiogenesis is an essential factor in the growth of tumors and metastases in various malignancies. An expanded level of angiogenesis is related to diminished endurance in BCa patients. This function assumes a fundamental part inside the human body, from the beginning phases of life to dangerous malignancy. Various factors, referred to as angiogenic factors, work to make a new capillary. Expanding proof demonstrates that angiogenesis is managed by microRNAs (miRNAs), which are small non-coding RNA with 19-25 nucleotides. MiRNA is a post-transcriptional regulator of gene expression that controls many critical biological processes. Endothelial miRNAs, referred to as angiomiRs, are probably concerned with tumor improvement and angiogenesis via regulation of pro-and anti-angiogenic factors. In this article, we reviewed therapeutic functions of miRNAs in BCa angiogenesis, several novel delivery carriers for miRNA-based therapeutics, as well as CRISPR/Cas9 as a targeted therapy in breast cancer.

miR-27b-3p inhibits estrogen secretion of goose granulosa cells by targeting CYP1B1 through the AMPK signaling pathway

Although miR-27b-3p has been evidenced to regulate the proliferation, apoptosis, and differentiation of a variety of mammalian cell types, its actions and mechanisms on ovarian cell steroidogenesis remains largely unknown in both mammalian and avian species. In this study, we aimed to determine the expression profiles of miR-27b-3p in granulosa cell layers during goose ovarian follicle development and to reveal its actions on estrogen (E₂) secretion of goose granulosa cells as well as the underlying regulatory mechanisms. It was observed that miR-27b-3p was ubiquitously expressed throughout follicle development but exhibited much higher levels in hierarchical- than in prehierarchical follicles. In cultured granulosa cells from the fourth through second largest preovulatory (F4-F2) follicles of goose, up- and downregulation of miR-27b-3p by using its mimic and inhibitor significantly decreased and increased E₂ secretion, respectively. Meanwhile, the mRNA levels of STAR and CYP19A1 were significantly reduced while those of CYP11A1 and 3βHSD were elevated in the mimic-transfected granulosa cells. By comparison, downregulation of miR-27b-3p enhanced the mRNA levels of STAR but had no significant effects on those of CYP19A1, CYP11A1, and 3βHSD. Results from bioinformatic prediction and luciferase reporter assay demonstrated that CYP1B1 was a downstream target of miR-27b-3p. Although the siRNA-mediated downregulation of CYP1B1 did not significantly change E₂ secretion by goose granulosa cells, it reduced the mRNA levels of STAR and CYP19A1 as well as those of LKB1 and AMPKα, which are involved in the AMPK signaling pathway. Taken together, these data suggest that miR-27b-3p plays an inhibitory role in E₂ secretion by goose F4-F2 granulosa cells, at least in part, by targeting CYP1B1 through the AMPK signaling pathway.

Progress on the role of traditional Chinese medicine in therapeutic angiogenesis of heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiovascular diseases are still the leading cause of death worldwide. Heart failure (HF), as the terminal stage of many cardiovascular diseases, has brought a heavy burden to the global medical system. Microvascular rarefaction (decreased myocardial capillary density) with reduced coronary flow reserve is a hallmark of HF and therapeutic myocardial angiogenesis is now emerging as a promising approach for the prevention and treatment in HF. Traditional Chinese medicine (TCM) has made remarkable achievements in the treatment of many cardiovascular diseases. Growing evidence have shown that their protective effect in HF is closely related to therapeutic angiogenesis.

AIM OF THE STUDY

This review is to enlighten the therapeutic effect and pro-angiogenic mechanism of TCM in HF, and provide valuable hints for the development of pro-angiogenic drugs for the treatment of HF.

MATERIALS AND METHODS

The relevant information about cardioprotective TCM was collected from electronic scientific databases such as PubMed, Web of Science, ScienceDirect, and China National Knowledge Infrastructure (CNKI).

RESULTS

The studies showed that TCM formulas, extracts, and compounds from herbal medicines can provide therapeutic effect in HF with their pro-angiogenic activity. Their actions are achieved mainly by regulating the key angiogenesis factors particularly VEGF, as well as related regulators including signal molecules and pathways, non-coding miRNAs and stem cells.

CONCLUSION

TCM and their active components might be promising in therapeutic angiogenesis for the treatment of HF.

The role of miRNAs in the diagnosis of stable atherosclerosis of different arterial territories: A critical review

Atherosclerotic disease is a major cause of morbidity and mortality worldwide. Atherosclerosis may be present in different arterial territories and as a single- or multi-territorial disease. The different phenotypes of atherosclerosis are attributable only in part to acquired cardiovascular risk factors and genetic Mendelian inheritance. miRNAs, which regulate the gene expression at the post-transcriptional level, may also contribute to such heterogeneity. Numerous miRNAs participate in the pathophysiology of atherosclerosis by modulating endothelial function, smooth vascular cell function, vascular inflammation, and cholesterol homeostasis in the vessel, among other biological processes. Moreover, miRNAs are present in peripheral blood with high stability and have the potential to be used as non-invasive biomarkers for the diagnosis of atherosclerosis. However, the circulating miRNA profile may vary according to the involved arterial territory, considering that atherosclerosis expression, including the associated molecular phenotype, varies according to the affected arterial territory. In this review, we discuss the specific circulating miRNA profiles associated with atherosclerosis of different arterial territories, the common circulating miRNA profile of stable atherosclerosis irrespective of the involved arterial territory, and the circulating miRNA signature of multi-territorial atherosclerosis. miRNAs may consist of a simple non-invasive method for discriminating atherosclerosis of different arterial sites. The limitations of miRNA profiling for such clinical application are also discussed.

Single Shot vs. Cocktail: A Comparison of Mono- and Combinative Application of miRNA-Targeted Mesyl Oligonucleotides for Efficient Antitumor Therapy

Simple Summary

Current approaches to the treatment of oncological diseases are still suffering from a lack of efficiency and selectivity and are accompanied by pronounced non-specific toxic effects. This study evaluated the antitumor potential of highly selective multitarget antisense downregulation of small non-coding RNA molecules—microRNAs—where dysregulation in cells frequently triggers oncotransformation and tumor development. We report herein that combinations of recently developed mesyl phosphoramidate oligonucleotides, targeted to multifunctional miRNA regulators miR-17, miR-21 and miR-155, exhibited potent synergistic antiproliferative and antimigrative effects on highly aggressive tumor cells. Furthermore, the significant antitumor activity of a cocktail of three antisense oligonucleotides targeted to miR-21, miR-17, and miR-155 almost completely suppressed lymphosarcoma RLS₄₀ tumor growth and exerted prominent antimetastatic effects in a melanoma B16 model. Such treatment elicited no sign of in vivo toxicity and even exhibited remedial effects on the liver of tumor-bearing mice.

Abstract

Rational combinations of sequence-specific inhibitors of pro-oncogenic miRNAs can efficiently interfere with specific tumor survival pathways, offering great promise for targeted therapy of oncological diseases. Herein, we uncovered the potential of multicomponent therapy by double or triple combinations of highly potent mesyl phosphoramidate (µ) antisense oligodeoxynucleotides targeted to three proven pro-oncogenic microRNAs—miR-17, miR-21, and miR-155. A strong synergism in the inhibition of proliferation and migration of B16 melanoma cells was demonstrated in vitro for pairs of µ-oligonucleotides, which resulted in vivo in profound inhibition (up to 85%) of lung metastases development after intravenous injection of µ-oligonucleotide-transfected B16 cells in mice. A clear benefit of µ-21-ON/µ-17-ON and µ-17-ON/µ-155-ON/µ-21-ON combination antitumor therapy was shown for the lymphosarcoma RLS₄₀ solid tumor model. In vivo administration of the µ-17-ON/µ-155-ON/µ-21-ON cocktail into RLS₄₀-bearing mice elicited fourfold delay of tumor growth as a result of strong inhibition of tumor mitotic activity. It was discovered that the cocktail of µ-21-ON/µ-17-ON/µ-155-ON led to a twofold decrease in total destructive changes in murine liver, which indicates both the reduction in toxic tumor burden and the absence of specific toxicity of the proposed therapy.

Regenerative Medicine and Angiogenesis; Focused on Cardiovascular Disease

Cardiovascular disease (CVD) is a major concern for health with high mortality rates around the world. CVD is often associated with partial or full occlusion of the blood vessel network. Changes in lifestyle can be useful for management early-stage disease but in the advanced stage, surgical interventions or pharmacological are needed to increase the blood flow through the affected tissue or to reduce the energy requirements. Regeneration medicine is a new science that has provided many different options for treating various diseases, especially in CVD over the years. Stem cell therapy, gene therapy, and tissue engineering are some of the powerful branches of the field that have given patients great hope in improving their condition. In this review, we attempted to examine the beneficial effects, challenges, and contradictory effects of angiogenesis in vivo, and in vitro models' studies of CVD. We hope that this information will be able to help other researchers to design new effective structures and open new avenues for the treatment of CVD with the help of angiogenesis and regeneration medicine in the future.

Serum microRNAs are key predictors of long-term heart failure and cardiovascular death after myocardial infarction

BACKGROUND

Patients with acute myocardial infarction (MI) are at high risk of upcoming events, in particular heart failure (HF), but reliable stratification methods are lacking. Our goal was to evaluate the potential role of circulating miRNAs as prognostic biomarkers in patients presenting with MI.

METHODS AND RESULTS

We conducted a prospective study among 311 consecutive patients hospitalized with MI (65% ST-segment elevation MI & median age of 55 years) with long-term follow-up. An initial screening was conducted to select candidate miRNAs, with subsequent study of 14 candidate miRNAs. The primary outcome was the composite of hospital admission for HF or cardiovascular death. During a mean follow-up of 2.1 years miR-21-5p, miR-23a-3p, miR27b-3p, miR-122-5p, miR210-3p, and miR-221-3p reliably predicted the primary outcome. Multivariate Cox regression analyses highlighted that miR-210-3p [hazard ratio (HR) 2.65 per 1 SD increase, P < 0.001], miR-23a-3p (HR 2.11 per 1 SD increase, P < 0.001), and miR-221-3p (HR 2.03 per 1 SD increase, P < 0.001) were able to accurately predict the primary outcome, as well as cardiovascular death, HF hospitalizations, and long-term New York Heart Association (NYHA) functional class. These three miRNAs clearly improved the performance of multivariate clinical models: ΔC-statistic = 0.10 [95% confidence interval (CI), 0.03-0.17], continuous net reclassification index = 34.8% (95%CI, 5.8-57.4%), and integrated discrimination improvement (P < 0.001).

CONCLUSIONS

This is the largest study evaluating the prognostic value of circulating miRNAs for HF-related events among patients with MI. We show that several miRNAs predict HF hospitalizations, cardiovascular mortality, and poor long-term NYHA status and improve current risk prediction methods.

Angiotensin II Promotes Skeletal Muscle Angiogenesis Induced by Volume-Dependent Aerobic Exercise Training: Effects on miRNAs-27a/b and Oxidant-Antioxidant Balance

Aerobic exercise training (ET) produces beneficial adaptations in skeletal muscles, including angiogenesis. The renin–angiotensin system (RAS) is highly involved in angiogenesis stimuli. However, the molecular mechanisms underlying capillary growth in skeletal muscle induced by aerobic ET are not completely understood. This study aimed to investigate the effects of volume-dependent aerobic ET on skeletal muscle angiogenesis involving the expression of miRNAs-27a and 27b on RAS and oxidant–antioxidant balance. Eight-week-old female Wistar rats were divided into three groups: sedentary control (SC), trained protocol 1 (P1), and trained protocol 2 (P2). P1 consisted of 60 min/day of swimming, 5×/week, for 10 weeks. P2 consisted of the same protocol as P1 until the 8th week, but in the 9th week, rats trained 2×/day, and in the 10th week, trained 3×/day. Angiogenesis and molecular analyses were performed in soleus muscle samples. Furthermore, to establish ET-induced angiogenesis through RAS, animals were treated with an AT1 receptor blocker (losartan). Aerobic ET promoted higher VO₂ peak and exercise tolerance values. In contrast, miRNA-27a and -27b levels were reduced in both trained groups, compared with the SC group. This was in parallel with an increase in the ACE1/Ang II/VEGF axis, which led to a higher capillary-to-fiber ratio. Moreover, aerobic ET induced an antioxidant profile increasing skeletal muscle SOD2 and catalase gene expression, which was accompanied by high nitrite levels and reduced nitrotyrosine concentrations in the circulation. Additionally, losartan treatment partially re-established the miRNAs expression and the capillary-to-fiber ratio in the trained groups. In summary, aerobic ET promoted angiogenesis through the miRNA-27a/b–ACE1/Ang II/VEGF axis and improved the redox balance. Losartan treatment demonstrates the participation of RAS in ET-induced vascular growth. miRNAs and RAS components are promising potential targets to modulate angiogenesis for combating vascular diseases, as well as potential biomarkers to monitor training interventions and physical performance.

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.

The Role of miR-181c in Mechanisms of Diabetes-Impaired Angiogenesis: An Emerging Therapeutic Target for Diabetic Vascular Complications

Diabetes mellitus is estimated to affect up to 700 million people by the year 2045, contributing to an immense health and economic burden. People living with diabetes have a higher risk of developing numerous debilitating vascular complications, leading to an increased need for medical care, a reduced quality of life and increased risk of early death. Current treatments are not satisfactory for many patients who suffer from impaired angiogenesis in response to ischaemia, increasing their risk of ischaemic cardiovascular conditions. These vascular pathologies are characterised by endothelial dysfunction and abnormal angiogenesis, amongst a host of impaired signaling pathways. Therapeutic stimulation of angiogenesis holds promise for the treatment of diabetic vascular complications that stem from impaired ischaemic responses. However, despite significant effort and research, there are no established therapies that directly stimulate angiogenesis to improve ischaemic complications such as ischaemic heart disease and peripheral artery disease, highlighting the immense unmet need. However, despite significant effort and research, there are no established therapies that directly stimulate angiogenesis in a clinical setting, highlighting the immense unmet need. MicroRNAs (miRNAs) are emerging as powerful targets for multifaceted diseases including diabetes and cardiovascular disease. This review highlights the potential role of microRNAs as therapeutic targets for rescuing diabetes-impaired angiogenesis, with a specific focus on miR-181c, which we have previously identified as an important angiogenic regulator. Here we summarise the pathways currently known to be regulated by miR-181c, which include the classical angiogenesis pathways that are dysregulated in diabetes, mitochondrial function and axonal guidance, and describe how these relate both directly and indirectly to angiogenesis. The pleiotropic actions of miR-181c across multiple key angiogenic signaling pathways and critical cellular processes highlight its therapeutic potential as a novel target for treating diabetic vascular complications.

Cell type-specific microRNA therapies for myocardial infarction

Current interventions fail to recover injured myocardium after infarction and prompt the need for development of cardioprotective strategies. Of increasing interest is the therapeutic use of microRNAs to control gene expression through specific targeting of mRNAs. In this Review, we discuss current microRNA-based therapeutic strategies, describing the outcomes and limitations of key microRNAs with a focus on target cell types and molecular pathways. Last, we offer a perspective on the outlook of microRNA therapies for myocardial infarction, highlighting the outstanding challenges and emerging strategies.

Elevated HDL-bound miR-181c-5p level is associated with diabetic vascular complications in Australian Aboriginal people

AIMS/HYPOTHESIS

Diabetes is a major burden on Australia's Indigenous population, with high rates of disease and vascular complications. Diabetic vascular complications are associated with impaired ischaemia-driven angiogenesis. MicroRNAs (miRNAs) are key players in the regulation of angiogenesis. HDL-cholesterol (HDL-c) levels are inversely associated with the risk of developing diabetic complications and HDL can carry miRNAs. HDL-miRNA profiles differ in disease states and may present as biomarkers with the capacity to act as bioactive signalling molecules. Recent studies have demonstrated that HDL becomes dysfunctional in a diabetic environment, losing its vasculo-protective effects and becoming more pro-atherogenic. We sought to determine whether HDL-associated miRNA profiles and HDL functionality were predictive of the severity of diabetic vascular complications in Australia's Indigenous population.

METHODS

HDL was isolated from plasma samples from Indigenous participants without diabetes ('Healthy'), with type 2 diabetes mellitus ('T2DM') and with diabetes-associated macrovascular complications (specifically peripheral artery disease, 'T2DM+Comp'). To assess HDL angiogenic capacity, human coronary artery endothelial cells were treated with PBS, reconstituted HDL (rHDL, positive control) or isolated HDL and then exposed to high-glucose (25 mmol/l) conditions. The expression levels of two anti-angiogenic miRNAs (miR-181c-5p and miR-223-3p) and one pro-angiogenic miRNA (miR-27b-3p) were measured in the HDL fraction, plasma and treated human coronary artery endothelial cells by quantitative real-time PCR. In vitro endothelial tubule formation was assessed using the Matrigel tubulogenesis assay.

RESULTS

Strikingly, we found that the levels of the anti-angiogenic miRNA miR-181c-5p were 14-fold higher (1454 ± 1346%) in the HDL from Aboriginal people with diabetic complications compared with both the Healthy (100 ± 121%, p < 0.05) and T2DM (82 ± 77%, p < 0.05) groups. Interestingly, we observed a positive correlation between HDL-associated miR-181c-5p levels and disease severity (p = 0.0020). Under high-glucose conditions, cells treated with rHDL, Healthy HDL and T2DM HDL had increased numbers of tubules (rHDL: 136 ± 8%, p < 0.01; Healthy HDL: 128 ± 6%, p < 0.01; T2DM HDL: 124 ± 5%, p < 0.05) and branch points (rHDL: 138 ± 8%, p < 0.001; Healthy HDL: 128 ± 6%, p < 0.01; T2DM HDL: 127 ± 5%, p < 0.01) concomitant with elevations in mRNA levels of the key hypoxia angiogenic transcription factor HIF1A (rHDL: 140 ± 10%, p < 0.01; Healthy HDL: 136 ± 8%, p < 0.01; T2DM HDL: 133 ± 9%, p < 0.05). However, this increase in angiogenic capacity was not observed in cells treated with T2DM + Comp HDL (tubule numbers: 113 ± 6%, p = 0.32; branch points: 113 ± 5%, p = 0.28; HIF1A: 117 ± 6%, p = 0.43), which could be attributed to the increase in cellular miR-181c-5p levels (T2DM + Comp HDL: 136 ± 7% vs PBS: 100 ± 9%, p < 0.05).

CONCLUSIONS/INTERPRETATION

In conclusion, HDL from Aboriginal people with diabetic complications had reduced angiogenic capacity. This impairment is associated with an increase in the expression of anti-angiogenic miR-181c-5p. These findings provide the rationale for a new way to better inform clinical diagnosis of disease severity with the potential to incorporate targeted, personalised HDL-miRNA intervention therapies to prevent further development of, or to reverse, diabetic vascular complications in Australian Aboriginal people.

The Role of Circulating Biomarkers in Peripheral Arterial Disease

Peripheral arterial disease (PAD) of the lower extremities is a chronic illness predominantly of atherosclerotic aetiology, associated to traditional cardiovascular (CV) risk factors. It is one of the most prevalent CV conditions worldwide in subjects >65 years, estimated to increase greatly with the aging of the population, becoming a severe socioeconomic problem in the future. The narrowing and thrombotic occlusion of the lower limb arteries impairs the walking function as the disease progresses, increasing the risk of CV events (myocardial infarction and stroke), amputation and death. Despite its poor prognosis, PAD patients are scarcely identified until the disease is advanced, highlighting the need for reliable biomarkers for PAD patient stratification, that might also contribute to define more personalized medical treatments. In this review, we will discuss the usefulness of inflammatory molecules, matrix metalloproteinases (MMPs), and cardiac damage markers, as well as novel components of the liquid biopsy, extracellular vesicles (EVs), and non-coding RNAs for lower limb PAD identification, stratification, and outcome assessment. We will also explore the potential of machine learning methods to build prediction models to refine PAD assessment. In this line, the usefulness of multimarker approaches to evaluate this complex multifactorial disease will be also discussed.

Cigarette Smoking, miR-27b Downregulation, and Peripheral Artery Disease: Insights into the Mechanisms of Smoking Toxicity

Cigarette smoking is a risk factor for the development of peripheral artery disease (PAD), although the proatherosclerotic mediators of cigarette smoking are not entirely known. We explored whether circulating microRNAs (miRNAs) are dysregulated in cigarette smokers and associated with the presence of PAD. Ninety-four participants were recruited, including 58 individuals without and 36 with PAD, 51 never smokers, 28 prior smokers, and 15 active smokers. The relative expression of six circulating miRNAs with distinct biological roles (miR-21, miR-27b, miR-29a, miR-126, miR-146, and miR-218) was assessed. Cigarette smoking was associated with the presence of PAD in multivariate analysis. Active smokers, but not prior smokers, presented miR-27b downregulation and higher leukocyte, neutrophil, and lymphocyte counts; miR-27b expression levels were independently associated with active smoking. Considering the metabolic and/or inflammatory abnormalities induced by cigarette smoking, miR-27b was independently associated with the presence of PAD and downregulated in patients with more extensive PAD. In conclusion, the atheroprotective miR-27b was downregulated in active smokers, but not in prior smokers, and miR-27b expression was independently associated with the presence of PAD. These unreported data suggest that the proatherogenic properties of cigarette smoking are mediated by a downregulation of miR-27b, which may be attenuated by smoking cessation.

Circulating miRNAs Are Associated with the Systemic Extent of Atherosclerosis: Novel Observations for miR-27b and miR-146

The mechanisms that regulate the systemic extent of atherosclerosis are not fully understood. We investigated whether the expression of circulating miRNAs is associated with the extent of stable atherosclerosis to a single territory or multiple territories (polyvascular) and with the severity of atherosclerosis in each territory. Ninety-four participants were prospectively recruited and divided into five age- and sex-matched groups: presenting no atherosclerosis, isolated coronary atherosclerosis, coronary and lower extremity atherosclerosis, coronary and carotid atherosclerosis, and atherosclerosis of the coronary, lower extremity, and carotid territories. The expression of six circulating miRNAs with distinct biological roles was assessed. The expression of miR-27b and miR-146 differed across groups (p < 0.05), showing a decrease in the presence of atherosclerosis, particularly in the three territories. miR-27b and miR-146 expression decreased in association with a higher severity of coronary, lower extremity, and carotid atherosclerosis. Polyvascular atherosclerosis involving the three territories was independently associated with a decreased miR-27b and miR-146 expression. Both miRNAs presented an area under the curve of ≥0.75 for predicting polyvascular atherosclerosis involving the three territories. To conclude, miR-27b and miR-146 were associated with the presence of severe polyvascular atherosclerosis and with the atherosclerosis severity in each territory. Both are potential biomarkers of severe systemic atherosclerosis.

Endothelial Cells as Tools to Model Tissue Microenvironment in Hypoxia-Dependent Pathologies

Endothelial cells (ECs) lining the blood vessels are important players in many biological phenomena but are crucial in hypoxia-dependent diseases where their deregulation contributes to pathology. On the other hand, processes mediated by ECs, such as angiogenesis, vessel permeability, interactions with cells and factors circulating in the blood, maintain homeostasis of the organism. Understanding the diversity and heterogeneity of ECs in different tissues and during various biological processes is crucial in biomedical research to properly develop our knowledge on many diseases, including cancer. Here, we review the most important aspects related to ECs’ heterogeneity and list the available in vitro tools to study different angiogenesis-related pathologies. We focus on the relationship between functions of ECs and their organo-specificity but also point to how the microenvironment, mainly hypoxia, shapes their activity. We believe that taking into account the specific features of ECs that are relevant to the object of the study (organ or disease state), especially in a simplified in vitro setting, is important to truly depict the biology of endothelium and its consequences. This is possible in many instances with the use of proper in vitro tools as alternative methods to animal testing.

Effect of miR-27b-5p on apoptosis of human vascular endothelial cells induced by simulated microgravity

Weightlessness-induced cardiovascular dysfunction can lead to physiological and pathological consequences. It has been shown that spaceflight or simulated microgravity can alter expression profiles of some microRNAs (miRNAs). Here, we attempt to identify the role of miRNAs in human umbilical vein endothelial cells (HUVECs) apoptosis under simulated microgravity. RNA-sequencing and quantitative real-time PCR (qRT-PCR) assays were used to identify differentially expressed miRNAs in HUVECs under simulated microgravity. Then we obtained the target genes of these miRNAs through target analysis software. Moreover, GO and KEGG enrichment analysis were performed. The effects of these miRNAs on HUVECs apoptosis were evaluated by flow cytometry, Western blot and Hoechst staining. Furthermore, we obtained the target gene of miR-27b-5p by luciferase assay, qRT-PCR and Western blot. Finally, we investigated the relationship between this target gene and miR-27b-5p in HUVECs apoptosis under normal gravity or simulated microgravity. We found 29 differentially expressed miRNAs in HUVECs under simulated microgravity. Of them, the expressions of 3 miRNAs were validated by qRT-PCR. We demonstrated that miR-27b-5p affected HUVECs apoptosis by inhibiting zinc fingers and homeoboxes 1 (ZHX1). Our results reported here demonstrate for the first time that simulated microgravity can alter the expression of some miRNAs in HUVECs and miR-27b-5p may protect HUVECs from apoptosis under simulated microgravity by targeting ZHX1.

Extracellular Vesicle miRNAs in the Promotion of Cardiac Neovascularisation

Cardiovascular disease (CVD) is the leading cause of mortality worldwide claiming almost 17. 9 million deaths annually. A primary cause is atherosclerosis within the coronary arteries, which restricts blood flow to the heart muscle resulting in myocardial infarction (MI) and cardiac cell death. Despite substantial progress in the management of coronary heart disease (CHD), there is still a significant number of patients developing chronic heart failure post-MI. Recent research has been focused on promoting neovascularisation post-MI with the ultimate goal being to reduce the extent of injury and improve function in the failing myocardium. Cardiac cell transplantation studies in pre-clinical models have shown improvement in cardiac function; nonetheless, poor retention of the cells has indicated a paracrine mechanism for the observed improvement. Cell communication in a paracrine manner is controlled by various mechanisms, including extracellular vesicles (EVs). EVs have emerged as novel regulators of intercellular communication, by transferring molecules able to influence molecular pathways in the recipient cell. Several studies have demonstrated the ability of EVs to stimulate angiogenesis by transferring microRNA (miRNA, miR) molecules to endothelial cells (ECs). In this review, we describe the process of neovascularisation and current developments in modulating neovascularisation in the heart using miRNAs and EV-bound miRNAs. Furthermore, we critically evaluate methods used in cell culture, EV isolation and administration.

Importance of the Use of Oxidative Stress Biomarkers and Inflammatory Profile in Aqueous and Vitreous Humor in Diabetic Retinopathy

Diabetic retinopathy is one of the leading causes of visual impairment and morbidity worldwide, being the number one cause of blindness in people between 27 and 75 years old. It is estimated that ~191 million people will be diagnosed with this microvascular complication by 2030. Its pathogenesis is due to alterations in the retinal microvasculature as a result of a high concentration of glucose in the blood for a long time which generates numerous molecular changes like oxidative stress. Therefore, this narrative review aims to approach various biomarkers associated with the development of diabetic retinopathy. Focusing on the molecules showing promise as detection tools, among them we consider markers of oxidative stress (TAC, LPO, MDA, 4-HNE, SOD, GPx, and catalase), inflammation (IL-6, IL-1ß, IL-8, IL-10, IL-17A, TNF-α, and MMPs), apoptosis (NF-kB, cyt-c, and caspases), and recently those that have to do with epigenetic modifications, their measurement in different biological matrices obtained from the eye, including importance, obtaining process, handling, and storage of these matrices in order to have the ability to detect the disease in its early stages.

Downregulation of miR-27b promotes skin wound healing in a rat model of scald burn by promoting fibroblast proliferation

The aim of the present study was to investigate the effect and mechanism of action of microRNA (miR)-27b on skin wound healing in rats with deep second-degree scald burns and in BJ human skin fibroblast cells. Rat models with deep second-degree scald burns were constructed and injected with miR-27b mimics and inhibitors at the wound site daily for 21 days. Healing of burned skin tissues was observed at 0, 3, 7, 14 and 21 days following modeling. H&E and Masson staining were used to observe the pathological structure and degree of collagen fibers in the burned skin tissues. The effects of miR-27b on BJ cell proliferation and migration were determined by MTT and scratch assays. Matrix metalloproteinase-1 (MMP-1), α-smooth muscle actin (α-SMA), collagen I and collagen III expression in rat skin tissues and BJ cells were measured via reverse transcription-quantitative PCR and western blot analysis. The results of the in vivo experiments demonstrated that miR-27b inhibition accelerated scalded skin healing and induced fibroblast growth. Furthermore, the in vitro experiments revealed that miR-27b inhibition increased BJ cell proliferation and migration. Furthermore, miR-27b inhibition upregulated MMP-1, α-SMA, collagen I and collagen III expression in the skin tissues and cells, while the overexpression of miR-27b demonstrated the opposite effect. In conclusion, the results of the present study revealed that miR-27b inhibition increased fibroblast proliferation, thereby accelerating scald wound healing in rats.

Stabilization of HIF-1α in Human Retinal Endothelial Cells Modulates Expression of miRNAs and Proangiogenic Growth Factors

Retinal hypoxia is one of the causative factors of diabetic retinopathy and is also one of the triggers of VEGF release. We hypothesized that specific dysregulated miRNAs in diabetic retinopathy could be linked to hypoxia-induced damage in human retinal endothelial cells (HRECs). We investigated in HRECs the effects of chemical (CoCl₂) hypoxia on the expression of HIF-1α, VEGF, PlGF, and of a focused set of miRNAs. We found that miR-20a-5p, miR-20b-5p, miR-27a-3p, miR-27b-3p, miR-206-3p, miR-381-3p correlated also with expression of TGFβ signaling pathway genes in HRECs, challenged with chemical hypoxic stimuli. In conclusion, our data suggest that retinal angiogenesis would be promoted, at least under HIF-1α activation, by upregulation of PlGF and other factors such as miRNAs, VEGFA, and TGFβ1.

The Role of DLLs in Cancer: A Novel Therapeutic Target

Delta-like ligands (DLLs) control Notch signaling. DLL1, DLL3 and DLL4 are frequently deregulated in cancer and influence tumor growth, the tumor vasculature and tumor immunity, which play different roles in cancer progression. DLLs have attracted intense research interest as anti-cancer therapeutics. In this review, we discuss the role of DLLs in cancer and summarize the emerging DLL-relevant targeting methods to aid future studies.

The Epigenetic Profile of Tumor Endothelial Cells. Effects of Combined Therapy with Antiangiogenic and Epigenetic Drugs on Cancer Progression

Tumors require a constant supply of nutrients to grow which are provided through tumor blood vessels. To metastasize, tumors need a route to enter circulation, that route is also provided by tumor blood vessels. Thus, angiogenesis is necessary for both tumor progression and metastasis. Angiogenesis is tightly regulated by a balance of angiogenic and antiangiogenic factors. Angiogenic factors of the vascular endothelial growth factor (VEGF) family lead to the activation of endothelial cells, proliferation, and neovascularization. Significant VEGF-A upregulation is commonly observed in cancer cells, also due to hypoxic conditions, and activates endothelial cells (ECs) by paracrine signaling stimulating cell migration and proliferation, resulting in tumor-dependent angiogenesis. Conversely, antiangiogenic factors inhibit angiogenesis by suppressing ECs activation. One of the best-known anti-angiogenic factors is thrombospondin-1 (TSP-1). In pathological angiogenesis, the balance shifts towards the proangiogenic factors and an angiogenic switch that promotes tumor angiogenesis. Here, we review the current literature supporting the notion of the existence of two different endothelial lineages: normal endothelial cells (NECs), representing the physiological form of vascular endothelium, and tumor endothelial cells (TECs), which are strongly promoted by the tumor microenvironment and are biologically different from NECs. The angiogenic switch would be also important for the explanation of the differences between NECs and TECs, as angiogenic factors, cytokines and growth factors secreted into the tumor microenvironment may cause genetic instability. In this review, we focus on the epigenetic differences between the two endothelial lineages, which provide a possible window for pharmacological targeting of TECs.

miR-27b promotes angiogenesis and skin repair in scalded rats through regulating VEGF-C expression

In this study, the effects of miR-27b on angiogenesis in skin repair procedure in rats with deep II degree scald were explored. The rat model of deep II scald was established. miR-27b mimics and inhibitor were injected daily at the wound site for 3 weeks. The healing of scald was observed at 0, 3, 7, 14, and 21 days after the model was established, and the pathological changes of skin were observed by HE and Masson's trichrome stains. Skin tissues were taken 14 days after the operation; CD31 and Ki-67 immunohistochemistry was exerted to evaluate neovascularization and proliferation. Human microvascular endothelial cells (HMEC-1) cells were cultured in vitro. miR-27b mimics or inhibitor was transfected to construct over-expression or inhibition cell lines. MTT assay, scratch test, and angiogenesis test were used to evaluate cell proliferation, migration, and vascular regeneration. Finally, RT-PCR and Western blot were exerted to determine the expression of vascular endothelial growth factor C (VEGF-C), epidermal growth factor (EGF) mRNAs, and protein, respectively. Control, inhibitor, mi-NC, VEGF-C, inhibitor + si-NC, and inhibitor + VEGF-C siRNA groups were used to further analyze the mechanism of miR-27b on VEGF-C; the above experiments were repeated. In contrast to model group, miR-27b inhibitor could significantly promote the healing of scalded skin, alleviate the pathological status of scalded, and promote the angiogenesis and proliferation (p < 0.05). In vitro, miR-27b inhibitor evidently promoted cell proliferation, migration, and angiogenesis and increased the expression of VEGF-C, EGF genes, and protein, while miR-27b mimics significantly reversed the above trends. Further studies shown that downregulation of miR-27b expression can promote the proliferation, migration, and angiogenesis of HMEC-1 cells by promoting the expression of VEGF-C. miR-27b promotes angiogenesis and skin repair in scalded rats through regulating VEGF-C expression.

Epigenetic regulators of the revascularization response to chronic arterial occlusion

Peripheral arterial disease (PAD) is the leading cause of lower limb amputation and estimated to affect over 202 million people worldwide. PAD is caused by atherosclerotic lesions that occlude large arteries in the lower limbs, leading to insufficient blood perfusion of distal tissues. Given the severity of this clinical problem, there has been long-standing interest in both understanding how chronic arterial occlusions affect muscle tissue and vasculature and identifying therapeutic approaches capable of restoring tissue composition and vascular function to a healthy state. To date, the most widely utilized animal model for performing such studies has been the ischaemic mouse hindlimb. Despite not being a model of PAD per se, the ischaemic hindlimb model does recapitulate several key aspects of PAD. Further, it has served as a valuable platform upon which we have built much of our understanding of how chronic arterial occlusions affect muscle tissue composition, muscle regeneration and angiogenesis, and collateral arteriogenesis. Recently, there has been a global surge in research aimed at understanding how gene expression is regulated by epigenetic factors (i.e. non-coding RNAs, histone post-translational modifications, and DNA methylation). Thus, perhaps not unexpectedly, many recent studies have identified essential roles for epigenetic factors in regulating key responses to chronic arterial occlusion(s). In this review, we summarize the mechanisms of action of these epigenetic regulators and highlight several recent studies investigating the role of said regulators in the context of hindlimb ischaemia. In addition, we focus on how these recent advances in our understanding of the role of epigenetics in regulating responses to chronic arterial occlusion(s) can inform future therapeutic applications to promote revascularization and perfusion recovery in the setting of 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.

The role of endothelial miRNAs in myocardial biology and disease

The myocardium is a highly structured pluricellular tissue which is governed by an intricate network of intercellular communication. Endothelial cells are the most abundant cell type in the myocardium and exert crucial roles in both healthy myocardium and during myocardial disease. In the last decade, microRNAs have emerged as new actors in the regulation of cellular function in almost every cell type. Here, we review recent evidence on the regulatory function of different microRNAs expressed in endothelial cells, also called endothelial microRNAs, in healthy and diseased myocardium. Endothelial microRNA emerged as modulators of angiogenesis in the myocardium, they are implicated in the paracrine role of endothelial cells in regulating cardiac contractility and homeostasis, and interfere in the crosstalk between endothelial cells and cardiomyocytes.

Comparing progression molecular mechanisms between lung adenocarcinoma and lung squamous cell carcinoma based on genetic and epigenetic networks: big data mining and genome-wide systems identification

Non-small-cell lung cancer (NSCLC) is the predominant type of lung cancer in the world. Lung adenocarcinoma (LADC) and lung squamous cell carcinoma (LSCC) are subtypes of NSCLC. We usually regard them as different disease due to their unique molecular characteristics, distinct cells of origin and dissimilar clinical response. However, the differences of genetic and epigenetic progression mechanism between LADC and LSCC are complicated to analyze. Therefore, we applied systems biology approaches and big databases mining to construct genetic and epigenetic networks (GENs) with next-generation sequencing data of LADC and LSCC. In order to obtain the real GENs, system identification and system order detection are conducted on gene regulatory networks (GRNs) and protein-protein interaction networks (PPINs) for each stage of LADC and LSCC. The core GENs were extracted via principal network projection (PNP). Based on the ranking of projection values, we got the core pathways in respect of KEGG pathway. Compared with the core pathways, we found significant differences between microenvironments, dysregulations of miRNAs, epigenetic modifications on certain signaling transduction proteins and target genes in each stage of LADC and LSCC. Finally, we proposed six genetic and epigenetic multiple-molecule drugs to target essential biomarkers in each progression stage of LADC and LSCC, respectively.

AngiomiRs: MicroRNAs driving angiogenesis in cancer (Review)

Angiogenesis is an important hallmark of cancer serving a key role in tumor growth and metastasis. Therefore, tumor angiogenesis has become an attractive target for development of novel drug therapies. An increased amount of anti‑angiogenic compounds is currently in preclinical and clinical development for personalized therapies. However, resistance to current angiogenesis inhibitors is emerging, indicating that there is a need to identify novel anti‑angiogenic agents. In the last decade, the field of microRNA biology has exploded revealing unsuspected functions in tumor angiogenesis. These small non‑coding RNAs, which have been dubbed as angiomiRs, may target regulatory molecules driving angiogenesis, such as cytokines, metalloproteinases and growth factors, including vascular endothelial growth factor, platelet‑derived growth factor, fibroblast growth factor, epidermal growth factor, hypoxia inducible factor‑1, as well as mitogen‑activated protein kinase, phosphoinositide 3‑kinase and transforming growth factor signaling pathways. The present review discusses the current progress towards understanding the functions of miRNAs in tumor angiogenesis regulation in diverse types of human cancer. Furthermore, the potential clinical application of angiomiRs towards anti‑angiogenic tumor therapy was explored.

The regulatory role of microRNAs in angiogenesis-related diseases

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at a post-transcriptional level via either the degradation or translational repression of a target mRNA. They play an irreplaceable role in angiogenesis by regulating the proliferation, differentiation, apoptosis, migration and tube formation of angiogenesis-related cells, which are indispensable for multitudinous physiological and pathological processes, especially for the occurrence and development of vascular diseases. Imbalance between the regulation of miRNAs and angiogenesis may cause many diseases such as cancer, cardiovascular disease, aneurysm, Kawasaki disease, aortic dissection, phlebothrombosis and diabetic microvascular complication. Therefore, it is important to explore the essential role of miRNAs in angiogenesis, which might help to uncover new and effective therapeutic strategies for vascular diseases. This review focuses on the interactions between miRNAs and angiogenesis, and miRNA-based biomarkers in the diagnosis, treatment and prognosis of angiogenesis-related diseases, providing an update on the understanding of the clinical value of miRNAs in targeting angiogenesis.

The regulation of miRNAs by reconstituted high-density lipoproteins in diabetes-impaired angiogenesis

Diabetic vascular complications are associated with impaired ischaemia-driven angiogenesis. We recently found that reconstituted high-density lipoproteins (rHDL) rescue diabetes-impaired angiogenesis. microRNAs (miRNAs) regulate angiogenesis and are transported within HDL to sites of injury/repair. The role of miRNAs in the rescue of diabetes-impaired angiogenesis by rHDL is unknown. Using a miRNA array, we found that rHDL inhibits hsa-miR-181c-5p expression in vitro and using a hsa-miR-181c-5p mimic and antimiR identify a novel anti-angiogenic role for miR-181c-5p. miRNA expression was tracked over time post-hindlimb ischaemic induction in diabetic mice. Early post-ischaemia when angiogenesis is important, rHDL suppressed hindlimb mmu-miR-181c-5p. mmu-miR-181c-5p was not detected in the plasma or within HDL, suggesting rHDL specifically targets mmu-miR-181c-5p at the ischaemic site. Three known angiogenic miRNAs (mmu-miR-223-3p, mmu-miR-27b-3p, mmu-miR-92a-3p) were elevated in the HDL fraction of diabetic rHDL-infused mice early post-ischaemia. This was accompanied by a decrease in plasma levels. Only mmu-miR-223-3p levels were elevated in the hindlimb 3 days post-ischaemia, indicating that rHDL regulates mmu-miR-223-3p in a time-dependent and site-specific manner. The early regulation of miRNAs, particularly miR-181c-5p, may underpin the rescue of diabetes-impaired angiogenesis by rHDL and has implications for the treatment of diabetes-related vascular complications.

Transcriptional Regulation of Macrophages Polarization by MicroRNAs

Diversity and plasticity are the hallmarks of cells from the monocyte-macrophage lineage. Macrophages undergo classical M1 or alternative M2 activation in response to the microenvironment signals. Several transcription factors, such as peroxisome proliferator-activated receptors, signal transducers and activators of transcription, CCAAT-enhancer-binding proteins, interferon regulatory factors, Kruppel-like factors, GATA binding protein 3, nuclear transcription factor-κB, and c-MYC, were found to promote the expression of specific genes, which dictate the functional polarization of macrophages. Importantly, these transcription factors can be regulated by microRNAs (miRNAs), a group of small non-coding RNAs, which regulate gene expression through translation repression or mRNA degradation. Recent studies have also revealed that miRNAs control macrophage polarization by regulating transcription factors in response to the microenvironment signals. This review will summarize recent progress of miRNAs in the transcriptional regulation of macrophage polarization and provide the insights into the development of macrophage-centered diagnostic and therapeutic strategies.

Atrial overexpression of microRNA-27b attenuates angiotensin II-induced atrial fibrosis and fibrillation by targeting ALK5

Atrial fibrosis influences atrial fibrillation (AF) development by transforming growth factor beta 1 (TGF-β1)/Smad pathway. Although microRNAs are implicated in the pathogenesis of various diseases, information regarding the functional role of microRNAs in atrial dysfunction is limited. In the present study, we found that microRNA-27b (miR-27b) was the dominant member of miR-27 family expressed in left atrium. Moreover, the expression of miR-27b was significantly reduced after angiotensin II (AngII) infusion. Masson's trichrome staining revealed that delivery of miR-27b adeno-associated virus to left atrium led to a decrease in atrial fibrosis induced by AngII. The increased expression of collagen I, collagen III, plasminogen activator inhibitor type 1 and alpha smooth muscle actin was also inhibited after miR-27b upregulation. In isolated perfused hearts, miR-27b restoration markedly attenuated AngII-induced increase in interatrial conduction time, AF incidence and AF duration. Furthermore, our data evidence that miR-27b is a novel miRNA that targets ALK5, a receptor of TGF-β1, through binding to the 3' untranslated region of ALK5 mRNA. Ectopic miR-27b suppressed luciferase activity and expression of ALK5, whereas inhibition of miR-27b increased ALK5 luciferase activity and expression. Additionally, miR-27b inhibited AngII-induced Smad-2/3 phosphorylation without altering Smad-1 activity. Taken together, our study demonstrates that miR-27b ameliorates atrial fibrosis and AF through inactivation of Smad-2/3 pathway by targeting ALK5, suggesting miR-27b may play an anti-fibrotic role in left atrium and function as a novel therapeutic target for the treatment of cardiac dysfunction.

MicroRNA expression profiles and clinicopathological implications in lung adenocarcinoma according to EGFR, KRAS, and ALK status

Lung adenocarcinoma has distinctive clinicopathological features that are related to specific genetic alterations, including EGFR and KRAS mutations and ALK rearrangement. MicroRNAs are small non-coding RNAs that post-transcriptionally regulate many important biological processes and influence cancer phenotypes. This study retrospectively investigated microRNA expression profiles, and their clinicopathological implications, in lung adenocarcinoma according to genetic status (EGFR, KRAS, ALK, and triple negative). A total of 72 surgically resected lung adenocarcinoma specimens (19 EGFR-mutated, 17 KRAS-mutated, 16 ALK-rearranged, and 20 triple negative cancers) were screened for 23 microRNAs using quantitative real-time reverse transcriptase polymerase chain reaction. We then evaluated the associations between the microRNA expressions and the cancers’ genetic and clinicopathological features. Eight microRNAs were associated with clinicopathological features, such as male sex and ever-smoker status (high miR-373-3p, miR-1343-3p, miR-138-1-3p, and miR-764; low miR-27b-3p) and vascular invasion (high miR-27b-3p; low miR-1343-3p and miR-764). Clustering and discriminant analyses revealed that the microRNA expression patterns in the ALK group were different from those in the EGFR and KRAS groups. Five microRNAs (high miR-1343-3p; low miR-671-3p, miR-103a-3p, let-7e, and miR-342-3p) were especially distinctive in the ALK group, compared to the EGFR and KRAS groups. Moreover, a significant association was observed between ALK-rearrangement, decreased miR-342-3p expression, and immunohistochemical loss of E-cadherin. Therefore, microRNA expression profiles appear to have distinctive clinicopathological implications in ALK-rearranged lung adenocarcinoma. Furthermore, the association of ALK rearrangement, decreased miR-342-3p expression, and E-cadherin loss might indicate that miR-342-3p is involved in the ALK-associated phenotypes and epithelial-mesenchymal transition.

MicroRNA as a Therapeutic Target in Cardiac Remodeling

MicroRNAs (miRNAs) are small RNA molecules that contain 18–25 nucleotides. The alterations in their expression level play crucial role in the development of many disorders including heart diseases. Myocardial remodeling is the final pathological consequence of a variety of myocardial diseases. miRNAs have central role in regulating pathogenesis of myocardial remodeling by modulating cardiac hypertrophy, cardiomyocytes injury, cardiac fibrosis, angiogenesis, and inflammatory response through multiple mechanisms. The balancing and tight regulation of different miRNAs is a key to drive the cellular events towards functional recovery and any fall in this leads to detrimental effect on cardiac function following various insults. In this review, we discuss the impact of alterations of miRNAs expression on cardiac hypertrophy, cardiomyocytes injury, cardiac fibrosis, angiogenesis, and inflammatory response. We have also described the targets (receptors, signaling molecules, transcription factors, etc.) of miRNAs on which they act to promote or attenuate cardiac remodeling processes in different type cells of cardiac tissues.

MicroRNA-27b functions as a new inhibitor of ovarian cancer-mediated vasculogenic mimicry through suppression of VE-cadherin expression

Aggressive cancer cells gain robust tumor vascular mimicry (VM) capability that promotes tumor growth and metastasis. VE-cadherin is aberrantly overexpressed in vasculogenic cancer cells and regarded as a master gene of tumor VM. Although microRNAs (miRNAs) play an important role in modulating tumor angiogenesis and cancer metastasis, the miRNA that targets VE-cadherin expression in cancer cells to inhibit tumor cell-mediated VM is enigmatic. In this study, we found that miR-27b levels are negatively co-related to VE-cadherin expression in ovarian cancer cells and tumor cell-mediated VM, and demonstrated that miR-27b could bind to the 3'-untranslated region (3'UTR) of VE-cadherin mRNA. Overexpression of miR-27b in aggressive ovarian cancer cell lines Hey1B and ES2 significantly diminished intracellular VE-cadherin expression; convincingly, the inhibitory effect of miR-27b could be reversed by miR-27b specific inhibitor. Intriguingly, miR-27b not only effectively suppressed ovarian cancer cell migration and invasion, but also markedly inhibited formation of ovarian cancer cell-mediated capillary-like structures in vitro and suppressed generation of functional tumor blood vessels in mice. Together, our study suggests that miR-27b functions as a new inhibitor of ovarian cancer cell-mediated VM through suppression of VE-cadherin expression, providing a new potential drug candidate for antitumor VM and anti-ovarian cancer therapy.

Promising therapeutic role of miR-27b in tumor

MicroRNAs are small nonprotein-encoding RNAs ranging from 18 to 25 nucleotides in size and regulate multiple biological pathways via directly targeting a variety of associated genes in cancers. MicroRNA-27b is a highly conserved MicroRNA throughout vertebrates and there are two homologs (hsa-miR-27a and hsa-miR-27b) in humans. MicroRNA-27b is an intragenic microRNA located on chromosome 9q22.1 within the C9orf3 gene, clustering with miR-23b and miR-24-1 in human. As a frequently dysregulated microRNA in human cancers, microRNA-27b could function as a tumor suppressor or an oncogenic microRNA. More and more studies indicate that microRNA-27b is involved in affecting various biological processes, such as angiogenesis, proliferation, metastasis, and drug resistance, and thus may act as a promising therapeutic target in human cancers. In this review, we discuss the role of microRNA-27b in detail and offer novel insights into molecular targeting therapy for cancers.

miR clusters target cellular functional complexes by defining their degree of regulatory freedom

Using the two paralog miR-23∼27∼24 clusters as an example and combining experimental and clinical data in a systematical approach to microRNA (miR) function and dysregulation, a complex picture of their roles in cancer is drawn. Various findings appear to be contradictory to a larger extent and cannot be fully explained by the classical regulatory network models and feedback loops that are mainly considered by one-to-one regulatory interactions of the involved molecules. Here, we propose an extended model of the regulatory role of miRs that, at least, supplements the usually considered single/oligo-target regulation of certain miRs. The cellular availability of the participating miR members in this model reflects an upper hierarchy level of intracellular and extracellular environmental influences, such as neighboring cells, soluble factors, hypoxia, chemotherapeutic drugs, and irradiation, among others. The novel model is based on the understanding of cellular functional complexes, such as for apoptosis, migration, and proliferation. These complexes consist of many regulatory components that can be targeted by miR cluster members to a different extent but may affect the functional complex in different ways. We propose that the final miR-related effect is a result of the possible degree of regulatory freedom provided by the miR effects on the whole functional complex structure. This degree of regulatory freedom defines to which extent the cellular functional complex can react in response to regulatory triggers, also understood as sensitization (more regulatory response options) or de-sensitization (less regulatory response options) of the system rather than single molecules.

Increased Wnt5a in squamous cell lung carcinoma inhibits endothelial cell motility

BACKGROUND

Angiogenesis is important both in normal tissue function and disease and represents a key target in lung cancer (LC) therapy. Unfortunately, the two main subtypes of non-small-cell lung cancers (NSCLC) namely, adenocarcinoma (AC) and squamous cell carcinoma (SCC) respond differently to anti-angiogenic e.g. anti-vascular endothelial growth factor (VEGF)-A treatment with life-threatening side effects, often pulmonary hemorrhage in SCC. The mechanisms behind such adverse reactions are still largely unknown, although peroxisome proliferator activator receptor (PPAR) gamma as well as Wnt-s have been named as molecular regulators of the process. As the Wnt microenvironments in NSCLC subtypes are drastically different, we hypothesized that the particularly high levels of non-canonical Wnt5a in SCC might be responsible for alterations in blood vessel growth and result in serious adverse reactions.

METHODS

PPARgamma, VEGF-A, Wnt5a, miR-27b and miR-200b levels were determined in resected adenocarcinoma and squamous cell carcinoma samples by qRT-PCR and TaqMan microRNA assay. The role of PPARgamma in VEGF-A expression, and the role of Wnts in overall regulation was investigated using PPARgamma knock-out mice, cancer cell lines and fully human, in vitro 3 dimensional (3D), distal lung tissue aggregates. PPARgamma mRNA and protein levels were tested by qRT-PCR and immunohistochemistry, respectively. PPARgamma activity was measured by a PPRE reporter system. The tissue engineered lung tissues expressing basal level and lentivirally delivered VEGF-A were treated with recombinant Wnts, chemical Wnt pathway modifiers, and were subjected to PPARgamma agonist and antagonist treatment.

RESULTS

PPARgamma down-regulation and VEGF-A up-regulation are characteristic to both AC and SCC. Increased VEGF-A levels are under direct control of PPARgamma. PPARgamma levels and activity, however, are under Wnt control. Imbalance of both canonical (in AC) and non-canonical (in SCC) Wnts leads to PPARgamma down-regulation. While canonical Wnts down-regulate PPARgamma directly, non-canonical Wnt5a increases miR27b that is known regulator of PPARgamma.

CONCLUSION

During carcinogenesis the Wnt microenvironment alters, which can downregulate PPARgamma leading to increased VEGF-A expression. Differences in the Wnt microenvironment in AC and SCC of NSCLC lead to PPARgamma decrease via mechanisms that differentially alter endothelial cell motility and branching which in turn can influence therapeutic response.

The Probability of Inconstancy in Assessment of Cardiac Function Post-Myocardial Infarction in Mice

In the present study, we explore the inherent variability that leads to overlaps in cardiac functional parameters between control and post-myocardial infarction (MI) mice. Heart failure was induced by Left Coronary Artery (LCA) ligation in mice. Average Ejection Fraction (EF) measured by echocardiography was lower in MI mice compared to control, but exhibited higher Standard Deviation (SD) and Standard Error (SEM), notably in 2D mode. Fractional Shortening (FS) showed a higher degree of overlap between MI and control mice even though the mean values were significantly different. Hemodynamic measurements of EF resulted in greater SD, SEM, ± 95% confidence intervals, and effect size. In comparing echocardiography at different time points, EF and FS were consistent by mean, but had apparent fluctuation in individual tracks, which were more obvious in MI than control mice. Hemodynamic measurements showed more complexity in data collection in mice in vivo. MI size showed variability that correlated with severity of cardiac function. These studies show that there is inherent variability in functional cardiac parameters after induction of heart failure by MI in mice. Analysis of these parameters by traditional statistical methods is insufficient, and we propose a more robust statistical analysis for proper data interpretation.

Harnessing gene and drug delivery for vascularizing engineered tissue platforms

Enhancement of tissue vascularization is a therapeutic target for many ischemic conditions, and is crucial for successful engraftment of therapeutic cells for tissue regeneration. The authors present opportunities for using these platforms for dissecting the role of angiogenic mechanisms and highlight recent gene and drug delivery strategies for enhancing vascularization of engineered tissues. Modular tissue engineering is featured as an example.

Identification of miR-34 regulatory networks in settings of disease and antimiR-therapy: Implications for treating cardiac pathology and other diseases

Expression of the miR-34 family (miR-34a, -34b, -34c) is elevated in settings of heart disease, and inhibition with antimiR-34a/antimiR-34 has emerged as a promising therapeutic strategy. Under chronic cardiac disease settings, targeting the entire miR-34 family is more effective than targeting miR-34a alone. The identification of transcription factor (TF)-miRNA regulatory networks has added complexity to understanding the therapeutic potential of miRNA-based therapies. Here, we sought to determine whether antimiR-34 targets secondary miRNAs via TFs which could contribute to antimiR-34-mediated protection. Using miRNA-Seq we identified differentially regulated miRNAs in hearts from mice with cardiac pathology due to transverse aortic constriction (TAC), and focused on miRNAs which were also regulated by antimiR-34. Two clusters of stress-responsive miRNAs were classified as "pathological" and "cardioprotective," respectively. Using ChIPBase we identified 45 TF binding sites on the promoters of "pathological" and "cardioprotective" miRNAs, and 5 represented direct targets of miR-34, with the capacity to regulate other miRNAs. Knockdown studies in a cardiomyoblast cell line demonstrated that expression of 2 "pathological" miRNAs (let-7e, miR-31) was regulated by one of the identified TFs. Furthermore, by qPCR we confirmed that expression of let-7e and miR-31 was lower in hearts from antimiR-34 treated TAC mice; this may explain why targeting the entire miR-34 family is more effective than targeting miR-34a alone. Finally, we showed that Acsl4 (a common target of miR-34, let-7e and miR-31) was increased in hearts from TAC antimiR-34 treated mice. In summary, antimiR-34 regulates the expression of other miRNAs and this has implications for drug development.

MicroRNA-27b suppresses Helicobacter pylori-induced gastric tumorigenesis through negatively regulating Frizzled7

MicroRNAs (miRNAs) are novel tools for cancer therapy. Frizzled7 (FZD7) is an important co-receptor in the WNT signaling pathway. The WNT signaling pathway is aberrantly activated in Helicobacter pylori (H. pylori)‑infected gastric cancer cells. However, the role of FZD7 in H. pylori‑induced gastric tumorigenesis remains unknown. In this study, we investigated the potential role of FZD7 in H. pylori-induced gastric tumorigenesis and validated the possibility that targeting of FZD7 by specific miRNA inhibits H. pylori-induced gastric tumorigenesis. First, we found that FZD7 was significantly induced by H. pylori infection in a dose- and time-dependent manner. Knockdown of FZD7 by FZD7 small interfering RNA effectively inhibited H. pylori infection-induced cell proliferation of gastric cancer cells. We found that microRNA-27b (miR-27b) was the predicted miRNA for FZD7 and that miR-27b negatively regulated FZD7 expression by targeting the 3'-untranslated region of FZD7. Furthermore, miR-27b overexpression significantly inhibited H. pylori infection-induced cell proliferation and WNT signaling pathway activation in gastric cancer cells. Restoration of FZD7 expression significantly attenuated the inhibitory effect of miR-27b overexpression on cell proliferation and WNT signaling pathway activation. Collectively, our study suggests that FZD7 triggered by H. pylori infection contributes to the H. pylori infection-induced cell proliferation that links the WNT. Thus, miR-27b may be a promising molecular target for the treatment of the disease.