Role of microRNAs in Vascular Remodeling

MicroRNA Expression in Patients with Coronary Artery Disease and Hypertension-A Systematic Review

Coronary artery disease (CAD) and hypertension significantly contribute to cardiovascular morbidity and mortality. MicroRNAs (miRNAs) have recently emerged as promising biomarkers and therapeutic targets for these conditions. This systematic review conducts a thorough analysis of the literature, with a specific focus on investigating miRNA expression patterns in patients with CAD and hypertension. This review encompasses an unspecified number of eligible studies that employed a variety of patient demographics and research methodologies, resulting in diverse miRNA expression profiles. This review highlights the complex involvement of miRNAs in CAD and hypertension and the potential for advances in diagnostic and therapeutic strategies. Future research endeavors are imperative to validate these findings and elucidate the precise roles of miRNAs in disease progression, offering promising avenues for innovative diagnostic tools and targeted interventions.

High-resolution magnetic resonance imaging investigation of the connection between the triglyceride-glucose index and intracranial arterial remodeling: a retrospective cross-sectional study

Background

Insulin resistance (IR) is associated with atherosclerotic plaque progression and the occurrence of stroke, with the triglyceride-glucose (TyG) index serving as a surrogate indicator. The present study aimed to investigate the association between TyG index levels and intracranial arterial remodeling in patients with acute ischemic stroke (AIS).

Methods

Patients with AIS who visited the Neurology Department of the Second Hospital of Hebei Medical University and underwent high-resolution magnetic resonance imaging (HR-MRI) between September 2018 and October 2021 were enrolled. A total of 123 patients were finally included in the study, with 81 excluded. The TyG index levels were measured, and the characteristics of intracranial atherosclerotic stenosis (ICAS) plaques were evaluated using HR-MRI. A logistic regression model was employed to analyze the relationship between TyG index levels and remodeling mode. Patients were divided into two groups, positive remodeling (PR) and non-positive remodeling (non-PR), based on the remodeling index (RI).

Results

Patients in the PR group had a higher TyG index than those in the non-PR group {median [interquartile range (IQR)]: 9.11 (8.82-9.51) vs. 8.72 (8.30-9.23), P<0.001}. After adjusting factors such as age and gender, the TyG index was found to be significantly correlated with intracranial arterial PR [odds ratio (OR): 3.169, 95% confidence interval (CI): 1.327-7.569, P=0.009]. In non-diabetes mellitus (DM) patients, the TyG index level in the PR group was significantly higher than that in the non-PR group (8.95±0.42 vs. 8.50±0.45, P<0.001), whereas there was no such difference in patients with DM.

Conclusions

TyG index was correlated with intracranial vessel PR, indicating that the TyG index level may be a useful marker for predicting intracranial vessel PR.

ATF4 promotes brain vascular smooth muscle cells proliferation, invasion and migration by targeting miR-552-SKI axis

Background

Studies have indicated vascular smooth muscle cells (VSMCs) played a crucial role in atherosclerosis and microRNAs (miRNAs) played key roles in biological functions of VSMCs. Whereas, the potential function and mechanism of miR-552 in VSMCs remains unclear. Our aim was to explore the role of miR-552 on VSMCs and underlying mechanism.

Material/Methods

MTT assay and transwell assay were used to measure the proliferation, invasion, and migration of human brain VSMCs (HBVSMCs) and mice VSMCs (mVSMCs), respectively. Bioinformatics tools and luciferase assay were adopted to verify the association between miR-552 and SKI. Rescue experiments were employed to assess the interaction of miR-552 and SKI in modulating biological functions in HBVSMCs and mVSMCs. The expression level of transcription factors (TFs)was measured via qRT-PCR assay. The effect of ATF4 on miR-552 and SKI expression was tested by qRT-PCR or western blot assay. Finally, chromatin immunoprecipitation (ChIP) assay and JASPAR databases were used to analyze the regulatory linkage between ATF4 and miR-552.

Results

We found that miR-552 was upregulated in HBVSMCs treated with PDGF-bb and miR-552 overexpression could promote proliferation, invasion, and migration of HBVSMCs and mVSMCs, whereas, miR-552 knockdown had the opposite impact. In addition, we also found that SKI was a direct target of miR-552, which reversed miR-552-mediated proliferation, invasion, and migration in HBVSMCs and mVSMCs. Furthermore, we also discovered that miR-552 overexpression promoted the effects of ATF4 elevation on proliferation, migration and invasion of HBVSMCs and mVSMCs, but, miR-552 decline had the opposite impact.

Conclusions

ATF4-miR-552-SKI axis played critical roles in the proliferation and migration of HBVSMCs and mVSMCs, which were closely involved in atherosclerosis (AS). Therefore, our findings might offer a novel therapeutic target for AS.

Transcriptional and Epigenetic Factors Associated with Early Thrombosis of Femoral Artery Involved in Arteriovenous Fistula

Arteriovenous fistulas (AVFs), created for hemodialysis in end-stage renal disease patients, mature through the outward remodeling of the outflow vein. However, early thrombosis and chronic inflammation are detrimental to the process of AVF maturation and precipitate AVF maturation failure. For the successful remodeling of the outflow vein, blood flow through the fistula is essential, but early arterial thrombosis attenuates this blood flow, and the vessels become thrombosed and stenosed, leading to AVF failure. The altered expression of various proteins involved in maintaining vessel patency or thrombosis is regulated by genes of which the expression is regulated by transcription factors and microRNAs. In this study, using thrombosed and stenosed arteries following AVF creation, we delineated transcription factors and microRNAs associated with differentially expressed genes in bulk RNA sequencing data using upstream and causal network analysis. We observed changes in many transcription factors and microRNAs that are involved in angiogenesis; vascular smooth muscle cell proliferation, migration, and phenotypic changes; endothelial cell function; hypoxia; oxidative stress; vessel remodeling; immune responses; and inflammation. These factors and microRNAs play a critical role in the underlying molecular mechanisms in AVF maturation. We also observed epigenetic factors involved in gene regulation associated with these molecular mechanisms. The results of this study indicate the importance of investigating the transcriptional and epigenetic regulation of AVF maturation and maturation failure and targeting factors precipitating early thrombosis and stenosis.

Minimally modified low-density lipoprotein upregulates mouse mesenteric arterial 5-HT1B receptor in vivo via activation of the JAK2/STAT3 pathway

OBJECTIVES

To explore whether minimally modified low-density lipoprotein (mmLDL) upregulates mesenteric arterial 5-hydroxytryptamine 1B (5-HT_1B) receptor expression by activating the JAK2/STAT3 signaling pathway.

METHODS

Mice were randomly divided into the following groups: the normal saline (NS), LDL, mmLDL, mmLDL+galiellactone (GL, a JAK2/STAT3 pathway inhibitor), and mmLDL+DMSO groups. The dose-response curve of mesenteric arterial ring constriction after administration of 5-carboxamidotryptamine (5-CT), an agonist of 5-HT_1B, was recorded with a microvascular tensiometer. JAK2, p-JAK2, STAT3, p-STAT3, and 5-HT_1B receptor protein expression levels were determined by Western blotting. 5-HT_1B receptor mRNA levels were measured by RT-PCR. 5-HT_1B receptor protein expression was determined by immunofluorescence.

RESULTS

Injection of mmLDL into the tail vein significantly increased the contractile dose-response curve after 5-CT stimulation, as the E_max was 82.15 ± 6.15% in the NS group and 171.88 ± 5.78% in the mmLDL group (P < 0.01); significantly elevated 5-HT_1B receptor mRNA and protein expression levels; and significantly increased p-JAK2 and p-STAT3 protein expression levels. After intraperitoneal injection of GL, the vasoconstrictive response was significantly reduced compared with that in the mmLDL group, as the E_max was decreased to 97.14 ± 1.20% (P < 0.01); 5-HT_1B receptor mRNA and protein expression levels were significantly reduced; STAT3 phosphorylation and p-JAK2 and p-STAT3 protein expression were not significantly changed; and 5-HT_1B receptor expression was altered via inhibition of p-STAT3 binding to DNA, which suppressed transcription.

CONCLUSIONS

mmLDL can upregulate 5-HT_1B receptor expression in mouse mesenteric arteries by activating the JAK2/STAT3 signaling pathway.

Activation of yes-associated protein mediates sphingosine-1-phosphate-induced proliferation and migration of pulmonary artery smooth muscle cells and its potential mechanisms

The aims of the present study were to examine the molecular mechanisms underlying sphingosine-1-phosphate (S1P)-induced rat pulmonary artery smooth muscle cells (PASMCs) proliferation/migration and to determine the effect of yes-associated protein (YAP) activation on S1P-induced PASMCs proliferation/migration and its potential mechanisms. S1P induced YAP dephosphorylation and nuclear translocation, upregulated microRNA-130a/b (miR-130a/b) expression, reduced bone morphogenetic protein receptor 2 (BMPR2), and inhibitor of DNA binding 1(Id1) expression, and promoted PASMCs proliferation and migration. Pretreatment of cells with Rho-associated protein kinase (ROCK) inhibitor Y27632 suppressed S1P-induced YAP activation, miR-130a/b upregulation, BMPR2/Id1 downregulation, and PASMCs proliferation/migration. Knockdown of YAP using small interfering RNA also suppressed S1P-induced alterations of miR-130a/b, BMPR2, Id1, and PASMCs behavior. In addition, luciferase reporter assay indicated that miR-130a/b directly regulated BMPR2 expression in PASMCs. Inhibition of miR-130a/b functions by anti-miRNA oligonucleotides attenuated S1P-induced BMPR2/Id1 downregulation and the proliferation and migration of PASMCs. Taken together, our study indicates that S1P induces activation of YAP through ROCK signaling and subsequently increases miR-130a/b expression, which, in turn, downregulates BMPR2 and Id1 leading to PASMCs proliferation and migration.

miR-34a regulates phenotypic modulation of vascular smooth muscle cells in intracranial aneurysm by targeting CXCR3 and MMP-2

MicroRNAs (miRNAs) dysregulation is tightly related to diseases including tumor, neuro disease and cardiovascular disease. In this study, we investigated the potential biological effects of miR-34a and its target CXCR3 in phenotypic modulation of vascular smooth muscle cells (VSMCs) of intracranial aneurysms (IAs). MiR-34a was found to be down-regulated in IAs patients tested by Real-time PCR and decreased in GEO data. Meanwhile, our study also showed miR-34a inhibited matrix metalloproteinases (MMPs) and migration of VSMCs. Besides, CXCR3 is a direct target of miR-34a identified via luciferase assay. CXCR3 showed inhibitory effect on SM-MHC, SM22 while promoted MMPs expression, cell proliferation and migration in VSMCs. MiR-34a reversed the effect of CXCR3 in VSMCs. In addition, MMP-2 is a competitive endogenous RNA (ceRNA) of CXCR3 sharing common miR-34a target. CXCR3 increased MMP-2 level through competitive endogenous RNA regulation by sponging endogenous miR-34a. In conclusion, miR-34a is down-regulated in IAs while CXCR3 is the direct target of miR-34a that regulates phenotypic modulation of VSMCs. CXCR3 increased MMP-2 level through competitive endogenous RNA regulation by sharing common miR-34a targets.

Targeting c-Jun in A549 Cancer Cells Exhibits Antiangiogenic Activity In Vitro and In Vivo Through Exosome/miRNA-494-3p/PTEN Signal Pathway

The oncogene c-Jun is activated by Jun N-terminal kinase (JNK). Exosomes are nanometer-sized membrane vesicles released from a variety of cell types, and are essential for cell-to-cell communication. By using specific JNK inhibitor SP600125 or CRISPR/Cas9 to delete c-Jun, we found that exosomes from SP600125-treated A549 cancer cells (Exo-SP) or from c-Jun-KO-A549 cells (Exo-c-Jun-KO) dramatically inhibited tube formation of HUVECs. And the miR-494 levels in SP600125 treated or c-Jun-KO A549 cells, Exo-SP or Exo-c-Jun-KO, and HUVECs treated with Exo-SP or Exo-c-Jun-KO were significantly decreased. Meanwhile, Exo-SP and Exo-c-Jun-KO enhanced expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN). Addition of miR-494 agomir in Exo-c-Jun-KO treated HUVECs inhibited PTEN expression and promoted tube formation, suggesting the target of miR-494 might be PTEN in HUVECs. Moreover, A549 tumor xenograft model and Matrigel plug assay demonstrated that Exo-c-Jun-KO attenuated tumor growth and angiogenesis through reducing miR-494. Taken together, inhibition of c-Jun in A549 cancer cells exhibited antiangiogenic activity in vitro and in vivo through exosome/miRNA-494-3p/PTEN signal pathway.

Identification of a Plasma Microrna Signature as Biomarker of Subaneurysmal Aortic Dilation in Patients with High Cardiovascular Risk

Patients with subaneurysmal aortic dilation (SAD; 25–29 mm diameter) are likely to progress to true abdominal aortic aneurysm (AAA). Despite these patients having a higher risk of all-cause mortality than subjects with aortic size <24 mm, early diagnostic biomarkers are lacking. MicroRNAs (miRs) are well-recognized potential biomarkers due to their differential expression in different tissues and their stability in blood. We have investigated whether a plasma miRs profile could identify the presence of SAD in high cardiovascular risk patients. Using qRT-PCR arrays in plasma samples, we determined miRs differentially expressed between SAD patients and patients with normal aortic diameter. We then selected 12 miRs to be investigated as biomarkers by construction of ROC curves. A total of 82 significantly differentially expressed miRs were found by qPCR array, and 12 were validated by qRT-PCR. ROC curve analyses showed that seven selected miRs (miR-28-3p, miR-29a-3p, miR-93-3p, miR-150-5p, miR-338-3p, miR-339-3p, and miR-378a-3p) could be valuable biomarkers for distinguishing SAD patients. MiR-339-3p showed the best sensitivity and specificity, even after combination with other miRs. Decreased miR-339-3p expression was associated with increased aortic abdominal diameter. MiR-339-3p, alone or in combination with other miRs, could be used for SAD screening in high cardiovascular risk patients, helping to the early diagnosis of asymptomatic AAA.

LincRNA-Cox2 promotes pulmonary arterial hypertension by regulating the let-7a-mediated STAT3 signaling pathway

It is well supported by the literature that the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) are critical for the development of pulmonary arterial hypertension (PAH). Long intergenic noncoding RNA COX2 (lincRNA-COX2) is a regulator of inflammation and might be conducive to the progression of atherosclerosis, while its role in PAH is still unclear. This study was performed to explore the role and mechanism of lincRNA-COX2 in PASMCs proliferation and migration in an anaerobic environment. PASMCs were treated by hypoxia to construct PAH cell models. RT-PCR and western blot were recruited to evaluate the expression levels of lincRNA-COX2, miR-let-7a and STAT3. Their roles in proliferation and cell and migration of PASMCs were determined by the CCK-8 assay, wound-healing assay, and flow cytometry. In peripheral blood samples from PAH patients and hypoxic PASMCs, lincRNA-COX2 expression was enhanced. Silencing lincRNA-COX2 inhibited hypoxia-induced PASMCs proliferation by influencing the G2/M phase of the cell cycle. Meanwhile, lincRNA-COX2 regulated STAT3 through miR-let-7a and its effects on hypoxic PASMCs worked through miR-let-7a/STAT3 axis. To conclude, silencing lincRNA-COX2 attenuated the development of hypoxic PASMCs. LincRNA-COX2/miR-let-7a/STAT3 axis might be considered as a novel target to treat PAH.

Role of the signal transducer and activator of transcription 3 protein in the proliferation of vascular smooth muscle cells

OBJECTIVES

Cardiovascular disease (CVD) remains the primary cause of morbidity and mortality worldwide. The abnormal proliferation of vascular smooth muscle cells (VSMCs) is a key event in the pathogenesis of CVD. The functional and phenotypic changes in vascular cells are mediated by complex signaling cascades that initiate and control genetic reprogramming. Many studies have demonstrated that signal transducer and activator of transcription 3 (STAT3) regulates a diverse array of functions relevant to atherosclerosis.

METHODS

In this review, we summarize the studies on the STAT3-mediated proliferation of VSMCs and subsequent CVDs such as hypertension, atherosclerosis, stroke, coronary artery disease, and myocardial infarction. Furthermore, we describe the general background of STAT3, its structure, function and regulation as well as the STAT3 signaling pathway. Finally, we highlight some potential issues and propose some solutions to these issues.Results and conclusions: STAT3 activation promotes the proliferation of VSMCs by regulating the transcription of genes. Studying the mechanism of VSMC proliferation induced by the STAT3 pathway is valuable for finding therapeutic targets for CVD.

MicroRNA-532-5p protects against atherosclerosis through inhibiting vascular smooth muscle cell proliferation and migration

Background

The present study aimed to explore the expression and clinical value of miR-532-5p in atherosclerosis (AS) patients, and analyze its regulating effect on biological behaviors of vascular smooth muscle cells (VSMCs).

Methods

A total of 103 AS patients and 77 healthy controls were included. The expression level of miR-532-5p was measured using quantitative real-time PCR (qRT-PCR). A receiver operating characteristic (ROC) analysis was counted to assess the diagnostic value of miR-532-5p in AS. CCK-8 and Transwell assay were used to detect the role of miR-532-5p in VSMCs proliferation and migration.

Results

MiR-532-5p was downregulated in AS patients compared with that in healthy controls. Serum miR-532-5p was inversely related to the carotid intima-media thickness (CIMT) in AS patients. A ROC curve was conducted with an area under the curve (AUC) of 0.897, with high sensitivity and specificity. Overexpression of miR-532-5p inhibited cell proliferation and migration in VSMCs, whereas miR-532-5p downregulation had a reverse effect.

Conclusions

Decreased expression of miR-532-5p might be a potential diagnostic biomarker for AS. Overexpression of miR-532-5p inhibits the proliferation and migration of VSMCs. The present results indicate a therapeutic potential of miR-532-5p for AS.

Role of microRNAs in Hemophilia and Thrombosis in Humans

MicroRNAs (miRNA) play an important role in gene expression at the posttranscriptional level by targeting the untranslated regions of messenger RNA (mRNAs). These small RNAs have been shown to control cellular physiological processes including cell differentiation and proliferation. Dysregulation of miRNAs have been associated with numerous diseases. In the past few years miRNAs have emerged as potential biopharmaceuticals and the first miRNA-based therapies have entered clinical trials. Our recent studies suggest that miRNAs may also play an important role in the pathology of genetic diseases that are currently considered to be solely due to mutations in the coding sequence. For instance, among hemophilia A patients there exist a small subset, with normal wildtype genes; i.e., lacking in mutations in the coding and non-coding regions of the F8 gene. Similarly, in many patients with missense mutations in the F8 gene, the genetic defect does not fully explain the severity of the disease. Dysregulation of miRNAs that target mRNAs encoding coagulation factors have been shown to disturb gene expression. Alterations in protein levels involved in the coagulation cascade mediated by miRNAs could lead to bleeding disorders or thrombosis. This review summarizes current knowledge on the role of miRNAs in hemophilia and thrombosis. Recognizing and understanding the functions of miRNAs by identifying their targets is important in identifying their roles in health and diseases. Successful basic research may result in the development and improvement of tools for diagnosis, risk evaluation or even new treatment strategies.

Meta-Analysis of the Potential Role of miRNA-21 in Cardiovascular System Function Monitoring

MicroRNAs (miRNAs) are short and noncoding RNA fragments that bind to the messenger RNA. They have different roles in many physiological or pathological processes. MicroRNA-21, one of the first miRNAs discovered, is encoded by the MIR21 gene and is located on the chromosomal positive strand 17q23.2. MicroRNA-21 is transcribed by polymerase II and has its own promoter sequence, although it is in an intron. It is intra- and extracellular and can be found in many body fluids, alone or combined with another molecule. It regulates many signalling pathways and therefore plays an important role in the cardiovascular system. Indeed, it is involved in the differentiation and migration of endothelial cells and angiogenesis. It contributes to the reconstruction of a myocardial infarction, and it can also act as a cellular connector or as an antagonist to cardiac cell apoptosis. By playing all these roles, it can be interesting to use it as a biomarker, especially for cardiovascular diseases.

Intimal regeneration after coronary endarterectomy and onlay grafting in coronary artery bypass grafting

OBJECTIVES

Coronary onlay grafting, with or without endarterectomy, has been widely used for the treatment of diffuse lesions. Recent studies have demonstrated excellent long-term patency and favorable remodeling of onlay anastomosis; however, the underlying mechanisms remain unknown. Here, we describe the mechanism of intimal regeneration based on postmortem pathological evaluation of a patient who had undergone onlay grafting with coronary endarterectomy.

METHODS

The onlay anastomosis was analyzed using a combination of immunohistological stainings, namely, H&E, vimentin, α-SMA, factor VIII, and Ki-67, to identify the source and mechanism of intimal regeneration after onlay grafting with endarterectomy.

RESULTS

Our results suggest that the regenerated endothelium derives from the smooth muscle cells of the endarterectomized media of the coronary artery and that it circumferentially covers the internal lumen of the arterial graft.

CONCLUSIONS

Intimal regeneration, derived from the smooth muscle cells of the endarterectomized coronary artery that proliferate toward the graft lumen, may be a key mechanism that underlies the observed favorable remodeling after onlay grafting during coronary endarterectomy.

miRNA-1, miRNA-145 as a Myocardial Infarction Diagnostic Biomarker

Many myocardial infarction biomarkers currently available but they are a lack of specificity, therefore present study suggests to evaluate the significant importance of miRNA-1, miRNA-145 as biomarkers for early diagnosis of myocardial infarction. A blood sample was collected from three groups. The first group was patients with acute myocardial infarction (MI), the Second group was patients who have a risk factor for MI, and the Third group included healthy volunteers. Serum blood of this sample used to RNA purification and cDNA application with stem-loop specific primer then miRNA-1, and miRNA-145 was quantitated by using RT-PCR. The level of miR-1 fold change was significantly highest in the MI group followed by risk group and then by control group (P<0.05). while of miRNA-145 fold change was significantly lowest in the MI group followed by risk group and then by control group (P<0.05). A receiver operator characteristic (ROC) analysis; the cut off value was identified at miRNA-1 of >5.28 fold change with a sensitivity of 91.67 % and a specificity of 90.7%, while the cut off value of miRNA-145 has cut off ≤ 0.7 fold change with a sensitivity of 95.83 % and a specificity of 89.47%. miRNA-1, miR145 has high sensitivity and Specificity in this study which was bushed to using them as an alone biomarker or supported for Another biomarker in AMI diagnosis.

Plasma levels of microRNA-21, -126 and -423-5p alter during clinical improvement and are associated with the prognosis of acute heart failure

MicroRNAs are associated with myocardial damage and heart failure (HF). The present study investigated whether the plasma levels of microRNA (miR)‑21, ‑126 and ‑423‑5p alter according to the (de)compensated state of patients with HF and are associated with all‑cause mortality. In 48 patients with HF admitted to the emergency room for an episode of acute decompensation, blood samples were collected to measure miR and B‑type natriuretic peptide levels within 24 h of hospital admission, at the time of hospital discharge, and a number of weeks post‑discharge (chronic stable compensated state). Levels of miR‑21, miR‑126 and miR‑423‑5p increased between admission and discharge, and decreased following clinical compensation. During follow‑up (up to 48 months), 38 patients (79%) were rehospitalized at least once and 21 patients (44%) succumbed. Patients who had increased levels of miR‑21 and miR‑126 at the time of clinical compensation exhibited better 24‑month survival and remained rehospitalization‑free for a longer period compared with those with low levels. Additionally, patients whose levels of miR‑423‑5p increased between admission and clinical compensation experienced fewer hospital readmissions in the 24 months following the time of clinical compensation compared with those who had decreased levels. It was concluded that the plasma levels of miR‑21, miR‑126 and miR‑423‑5p altered during clinical improvement and were associated with the prognosis of acute decompensated HF.

Exploring ribosome composition and newly synthesized proteins through proteomics and potential biomedical applications

INTRODUCTION

Protein synthesis is the outcome of tightly regulated gene expression which is responsive to a variety of conditions. Efforts are ongoing to monitor individual stages of protein synthesis to ensure maximum efficiency and accuracy. Due to post-transcriptional regulation mechanisms, the correlation between translatome and proteome is higher than between transcriptome and proteome. However, the most accurate approach to assess the key modulators and final protein expression is directly by using proteomics. Areas covered: This review covers various proteomic strategies that were used to better understand post-transcriptional regulation, specifically during and early after translation. The methods that identify both regulatory proteins associated with translational components and newly synthesized proteins are discussed. Expert commentary: Emerging proteomic approaches make it possible to monitor protein dynamics in cells, tissues and whole animals. The ability to detect alteration in protein abundance soon after their synthesis enables earlier recognition of disease causing factors and candidates to prevent/rectify disease phenotype.

MicroRNA-27a/b mediates endothelin-1-induced PPARγ reduction and proliferation of pulmonary artery smooth muscle cells

The down-regulation of peroxisome proliferator-activated receptor γ (PPARγ) expression has been found to correlate with the proliferation of pulmonary artery smooth muscle cells (PASMC), pulmonary vascular remodeling and pulmonary hypertension, while the molecular mechanisms underlying PPARγ reduction in PASMC remain largely unclear. The aim of the current study is to address this issue. Endothelin-1 (ET-1) dose- and time-dependently resulted in PPARγ reduction and proliferation of primary cultured rat PASMC, which was accompanied by the activation of nuclear factor-kappaB (NF-κB) and subsequent induction of microRNA-27a/b (miR-27a/b) expression. Chromatin immunoprecipitation assay revealed that NF-κB directly bound to the promoter regions of miR-27a/b. Luciferase reporter assay identified that miR-27a/b directly regulates the expression of PPARγ in PASMC. Further study indicated that the presence of either NF-κB inhibitor pyrrolidinedithiocarbamate or prior silencing miR-27a/b with anti-miRNA oligonucleotides suppressed ET-1-induced PPARγ reduction and proliferation of PASMC, while overexpression of miR-27a/b reduced PPARγ expression and enhanced PASMC proliferation. Taken together, our study demonstrates that ET-1 stimulates miR-27a/b expression by activation of the NF-κB pathway, which in turn results in PPARγ reduction and contributes to ET-1-induced PASMC proliferation.

Let-7a-transfected mesenchymal stem cells ameliorate monocrotaline-induced pulmonary hypertension by suppressing pulmonary artery smooth muscle cell growth through STAT3-BMPR2 signaling

Background

Cell-based gene therapy has become a subject of interest for the treatment of pulmonary arterial hypertension (PAH), a devastating disease characterized by pulmonary artery smooth muscle cell (PASMC) hyperplasia. Mesenchymal stem cells (MSCs) have been recently acknowledged as a potential cell vector for gene therapy. Here, we investigated the effect of MSC-based let-7a for PAH.

Methods

After isolation and identification of MSCs from rat bone marrow, cells were infected with recombinant adenovirus vector Ad-let-7a. Lewis rats were subcutaneously injected with monocrotaline (MCT) to induce PAH, followed by the administration of MSCs, MSCs-NC (miR-control), or MSC-let-7a, respectively. Then, right ventricular systolic pressure (RVSP), right ventricular hypertrophy, and pulmonary vascular remodeling were evaluated. Rat pulmonary artery smooth muscle cells (rPASMCs) under hypoxia were co-cultured with MSCs or MSC-let-7a. Cell proliferation and apoptosis were separately determined by ³H thymidine incorporation and flow cytometry analysis. The underlying mechanism was also investigated.

Results

MSC transplantation enhanced let-7a levels in MCT-induced PAH rats. After injection with MSC-let-7a, RVSP, right ventricular hypertrophy, and pulmonary vascular remodeling were notably ameliorated, indicating a protective effect of MSC-let-7a against PAH. When co-cultured with MSC-let-7a, hypoxia-triggered PASMC proliferation was obviously attenuated, concomitant with the decrease in cell proliferation-associated proteins. Simultaneously, the resistance of PASMCs to apoptosis was remarkably abrogated by MSC-let-7a administration. A mechanism assay revealed that MSC-let-7a restrained the activation of signal transducers and activators of transcription 3 (STAT3) and increased its downstream bone morphogenetic protein receptor 2 (BMPR2) expression. Importantly, preconditioning with BMPR2 siRNA dramatically abated the suppressive effects of MSC-let-7a on PASMC proliferation and apoptosis resistance.

Conclusions

Collectively, this study suggests that MSCs modified with let-7a may ameliorate the progression of PAH by inhibiting PASMC growth through the STAT3-BMPR2 signaling, supporting a promising therapeutic strategy for PAH patients.

Getting to the heart of intracellular glucocorticoid regeneration: 11β-HSD1 in the myocardium

Corticosteroids influence the development and function of the heart and its response to injury and pressure overload via actions on glucocorticoid (GR) and mineralocorticoid (MR) receptors. Systemic corticosteroid concentration depends largely on the activity of the hypothalamic-pituitary-adrenal (HPA) axis, but glucocorticoid can also be regenerated from intrinsically inert metabolites by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), selectively increasing glucocorticoid levels within cells and tissues. Extensive studies have revealed the roles for glucocorticoid regeneration by 11β-HSD1 in liver, adipose, brain and other tissues, but until recently, there has been little focus on the heart. This article reviews the evidence for glucocorticoid metabolism by 11β-HSD1 in the heart and for a role of 11β-HSD1 activity in determining the myocardial growth and physiological function. We also consider the potential of 11β-HSD1 as a therapeutic target to enhance repair after myocardial infarction and to prevent the development of cardiac remodelling and heart failure.

Inhibition of Aberrant MicroRNA-133a Expression in Endothelial Cells by Statin Prevents Endothelial Dysfunction by Targeting GTP Cyclohydrolase 1 in Vivo

Supplemental Digital Content is available in the text.

Background:

GTP cyclohydrolase 1 (GCH1) deficiency is critical for endothelial nitric oxide synthase uncoupling in endothelial dysfunction. MicroRNAs (miRs) are a class of regulatory RNAs that negatively regulate gene expression. We investigated whether statins prevent endothelial dysfunction via miR-dependent GCH1 upregulation.

Methods:

Endothelial function was assessed by measuring acetylcholine-induced vasorelaxation in the organ chamber. MiR-133a expression was assessed by quantitative reverse transcription polymerase chain reaction and fluorescence in situ hybridization.

Results:

We first demonstrated that GCH1 mRNA is a target of miR-133a. In endothelial cells, miR-133a was robustly induced by cytokines/oxidants and inhibited by lovastatin. Furthermore, lovastatin upregulated GCH1 and tetrahydrobiopterin, and recoupled endothelial nitric oxide synthase in stressed endothelial cells. These actions of lovastatin were abolished by enforced miR-133a expression and were mirrored by a miR-133a antagomir. In mice, hyperlipidemia- or hyperglycemia-induced ectopic miR-133a expression in the vascular endothelium, reduced GCH1 protein and tetrahydrobiopterin levels, and impaired endothelial function, which were reversed by lovastatin or miR-133a antagomir. These beneficial effects of lovastatin in mice were abrogated by in vivo miR-133a overexpression or GCH1 knockdown. In rats, multiple cardiovascular risk factors including hyperglycemia, dyslipidemia, and hyperhomocysteinemia resulted in increased miR-133a vascular expression, reduced GCH1 expression, uncoupled endothelial nitric oxide synthase function, and induced endothelial dysfunction, which were prevented by lovastatin.

Conclusions:

Statin inhibits aberrant miR-133a expression in the vascular endothelium to prevent endothelial dysfunction by targeting GCH1. Therefore, miR-133a represents an important therapeutic target for preventing cardiovascular diseases.