Molecular mechanisms in vascular injury induced by hypertension: Expression and role of microRNA-34a

Targeting the microRNA-34a as a Novel Therapeutic Strategy for Cardiovascular Diseases

Cardiovascular diseases (CVDs) are still the main cause of morbidity and mortality worldwide and include a group of disorders varying from vasculature, myocardium, arrhythmias and cardiac development. MicroRNAs (miRs) are endogenous non-coding RNAs with 18–23 nucleotides that regulate gene expression. The miR-34 family, including miR-34a/b/c, plays a vital role in the regulation of myocardial physiology and pathophysiological processes. Recently, miR-34a has been implicated in cardiovascular fibrosis, dysfunction and related cardiovascular disorders as an essential regulator. Interestingly, there is a pivotal link among miR-34a, cardiovascular fibrosis, and Smad4/TGF-β1 signaling. Notably, both loss-of-function and gain-of-function approaches identified the critical roles of miR-34a in cardiovascular apoptosis, autophagy, inflammation, senescence and remodeling by modulating multifunctional signaling pathways. In this article, we focus on the current understanding of miR-34a in biogenesis, its biological effects and its implications for cardiac pathologies including myocardial infarction, heart failure, ischaemia reperfusion injury, cardiomyopathy, atherosclerosis, hypertension and atrial fibrillation. Thus, further understanding of the effects of miR-34a on cardiovascular diseases will aid the development of effective interventions. Targeting for miR-34a has emerged as a potential therapeutic target for cardiovascular dysfunction and related diseases.

Peptidomics analysis revealed that a novel peptide VMP‑19 protects against Ang II‑induced injury in human umbilical vein endothelial cells

Vascular endothelial dysfunction is a vital pathological change in hypertension, which is mainly caused by apoptosis and oxidative stress injury of vascular endothelial cells. Peptidomics is a method for the direct analysis of small bioactive peptides in various biological samples using liquid chromatography‑mass spectrometry (MS)/MS. Given the advantages of the low molecular weight, optimum targeting and easy access to cells, peptides have attracted extensive attention in the field of drug research. However, to the best of our knowledge, little is currently known regarding the role of peptides in vascular endothelial injury. In order to investigate the peptides involved in vascular endothelial protection, MS was used to analyze the peptide profiles in the supernatant of human umbilical vein endothelial cells (HUVECs) stimulated by Ang II. The results revealed that 211 peptides were identified, of which six were upregulated and 13 were downregulated when compared with the control group. Subsequently, the present study analyzed the physical and chemical properties and biological functions of identified peptides by bioinformatics, and successfully screened a peptide (LLQDSVDFSLADAINTEFK) named VMP‑19 that could alleviate the apoptosis and oxidative stress injury of HUVECs induced by Ang II. In conclusion, to the best of our knowledge, the present study was the first to use peptidomics to analyze the peptide profiles of supernatant secreted by HUVECs, and revealed that the novel peptide VMP‑19 could protect HUVECs from apoptosis and oxidative stress injury. The results of the present study could provide novel insights into treatment strategies for hypertension.

Exosomal microRNAs in the development of essential hypertension and its potential as biomarkers

MicroRNAs (miRNAs) are small regulatory molecules that are involved in posttranscriptional modifications. These noncoding RNAs are usually ferried by extracellular carriers such as exosomes or other protein and lipid carriers inside a range of body fluids including plasma and urine. Due to their ability to withstand harsh external conditions, exosomal miRNAs possess enormous potential as noninvasive disease biomarkers for, notably hypertension, whereby exosomal miRNAs have been implicated in its pathophysiological processes. More importantly, alterations in the microenvironment as a result of disease progression can induce active and selective loading of miRNAs into exosomes. In this paper, we first review the mechanisms of miRNA loading into exosomes, followed by the roles of exosomal miRNAs in the development of hypertension, and the potentials of exosomal miRNAs as biomarkers in comparison with other free circulating miRNAs. Finally, challenges and future research surrounding exosomal miRNAs will also be discussed. This review will aid in the understanding of noninvasive biomarkers for the early diagnosis of hypertension and for probing therapeutic efficacy.

MicroRNA-34a: the bad guy in age-related vascular diseases

The age-related vasculature alteration is the prominent risk factor for vascular diseases (VD), namely, atherosclerosis, abdominal aortic aneurysm, vascular calcification (VC) and pulmonary arterial hypertension (PAH). The chronic sterile low-grade inflammation state, alias inflammaging, characterizes elderly people and participates in VD development. MicroRNA34-a (miR-34a) is emerging as an important mediator of inflammaging and VD. miR-34a increases with aging in vessels and induces senescence and the acquisition of the senescence-associated secretory phenotype (SASP) in vascular smooth muscle (VSMCs) and endothelial (ECs) cells. Similarly, other VD risk factors, including dyslipidemia, hyperglycemia and hypertension, modify miR-34a expression to promote vascular senescence and inflammation. miR-34a upregulation causes endothelial dysfunction by affecting ECs nitric oxide bioavailability, adhesion molecules expression and inflammatory cells recruitment. miR-34a-induced senescence facilitates VSMCs osteoblastic switch and VC development in hyperphosphatemia conditions. Conversely, atherogenic and hypoxic stimuli downregulate miR-34a levels and promote VSMCs proliferation and migration during atherosclerosis and PAH. MiR34a genetic ablation or miR-34a inhibition by anti-miR-34a molecules in different experimental models of VD reduce vascular inflammation, senescence and apoptosis through sirtuin 1 Notch1, and B-cell lymphoma 2 modulation. Notably, pleiotropic drugs, like statins, liraglutide and metformin, affect miR-34a expression. Finally, human studies report that miR-34a levels associate to atherosclerosis and diabetes and correlate with inflammatory factors during aging. Herein, we comprehensively review the current knowledge about miR-34a-dependent molecular and cellular mechanisms activated by VD risk factors and highlight the diagnostic and therapeutic potential of modulating its expression in order to reduce inflammaging and VD burn and extend healthy lifespan.

Decreased Urinary Levels of SIRT1 as Non-Invasive Biomarker of Early Renal Damage in Hypertension

Sirtuins have become important players in renal damage in hypertension and diabetes, but their value as biomarkers is poorly assessed. The aims of the study were to evaluate the levels of sirtuin1 (SIRT1), and two miRNAs that regulate SIRT1 expression in hypertensive patients with incipient renal damage with and without diabetes. We quantified urinary SIRT1 and claudin 1 (CLDN1) mRNA and miR34-a and miR-200a levels by quantitative real-time polymerase chain reaction (RT-qPCR) from patients and in cultured podocytes treated with high glucose and angiotensin II. Western blot and fluorescence analyses were also performed. We found decreased SIRT1 levels in patients with increased urinary albumin excretion (UAE), the lowest with diabetes presence, and a strong association with UAE, discriminating incipient renal damage. In vitro experiments also showed SIRT1 overall decreases in podocyte cultures under treatment conditions. In urine samples, miR-34a was reduced and miR-200a increased, both related to UAE levels. However, both miRNAs were generally increased in podocyte cultures under high glucose and angiotensin-II treatment. These results show a significant urinary SIRT1 decrease in albuminuric hypertensive patients, strongly associated with albuminuria, suggesting that SIRT1 could be a potential and non-invasive method to assess incipient renal damage in hypertensive patients.

miR-34a targets PAI-1 to regulate urinary microalbumin and renal function in hypertensive mice

Background

The aim of the study is to investigate the effects of miR-34a targeted at PAI-1 on urinary microalbumin and renal function in hypertensive mice.

Methods

Twenty specific-pathogen-free (SPF) BPN/3J mice were selected in normal group, and 120 SPF BPH/2J mice were evenly divided into model group, negative control group, miR-34a mimic group, miR-34a inhibitor group, Si-PAI-1 group, and miR-34a inhibitor + Si-PAI-1 group. qRT-PCR was used to detect the expression of miR-34a and PAI-1 mRNA. The protein expressions of PAI-1, angiotensin-converting enzyme (ACE) and ACE2 were detected by Western blot. Serum levels of AngII and Ang1-7 were detected by ELISA.

Results

miR-34a negatively regulated the expression of PAI-1. Compared with the normal group, mice in the other groups had significantly lower body weight, increased systolic blood pressure and 24-h urinary microalbumin content, decreased miR-34a expression, superoxide dismutase (SOD) and nitric oxide (NO) content, and ACE2 protein expression, and increased PAI-1 expression, serum creatinine (Scr), blood urea nitrogen (BUN) malondialdehyde (MDA), AngII and Ang1-7 levels, and ACE protein expression (all P < 0.05). Compared with the model group, mice in the miR-34a mimic group and Si-PAI-1 group had no significant changes in body weight (all P > 0.05), while they had significantly lower systolic blood pressure and 24-h urinary microalbumin content, increased SOD and NO levels and ACE2 protein expression, and decreased PAI-1 expression, Scr, BUN, MDA, AngII and Ang1-7 levels, and ACE protein expression (all P < 0.05). Compared with the miR-34a inhibitor group, symptoms in miR-34a inhibitor + Si-PAI-1 group were significantly improved (all P < 0.05).

Conclusions

miR-34a can inhibit the expression of PAI-1, thereby reducing urinary microalbumin content in hypertensive mice and protecting their renal function.

Use of Human Umbilical Vein Endothelial Cells (HUVEC) as a Model to Study Cardiovascular Disease: A Review

Cardiovascular disease (CVD) is the leading cause of death worldwide, and extensive research has been performed to understand this disease better, using various experimental models. The endothelium plays a crucial role in the development of CVD, since it is an interface between bloodstream components, such as monocytes and platelets, and other arterial wall components. Human umbilical vein endothelial cell (HUVEC) isolation from umbilical cord was first described in 1973. To date, this model is still widely used because of the high HUVEC isolation success rate, and because HUVEC are an excellent model to study a broad array of diseases, including cardiovascular and metabolic diseases. We here review the history of HUVEC isolation, the HUVEC model over time, HUVEC culture characteristics and conditions, advantages and disadvantages of this model and finally, its applications in the area of cardiovascular diseases.