MicroRNA miR-191 targets the zinc finger transcription factor Egr-1 and suppresses intimal thickening after carotid injury

EGR1 transcriptionally regulates SVEP1 to promote proliferation and migration in human coronary artery smooth muscle cells

A low-frequency variant of sushi, von Willebrand factor type A, EGF, and pentraxin domain-containing protein 1 (SVEP1) is associated with the risk of coronary artery disease, as determined by a genome-wide association study. SVEP1 induces vascular smooth muscle cell proliferation and an inflammatory phenotype to promote atherosclerosis. In the present study, qRT‒PCR demonstrated that the mRNA expression of SVEP1 was significantly increased in atherosclerotic plaques compared to normal tissues. Bioinformatics revealed that EGR1 was a transcription factor for SVEP1. The results of the luciferase reporter assay, siRNA interference or overexpression assay, mutational analysis and ChIP confirmed that EGR1 positively regulated the transcriptional activity of SVEP1 by directly binding to its promoter. EGR1 promoted human coronary artery smooth muscle cell (HCASMC) proliferation and migration via SVEP1 in response to oxidized low-density lipoprotein (ox-LDL) treatment. Moreover, the expression level of EGR1 was increased in atherosclerotic plaques and showed a strong linear correlation with the expression of SVEP1. Our findings indicated that EGR1 binding to the promoter region drive SVEP1 transcription to promote HCASMC proliferation and migration.

Serum MicroRNA-191-5p Levels in Vascular Complications of Type 1 Diabetes: The EURODIAB Prospective Complications Study

CONTEXT

MicroRNA-191-5p regulates key cellular processes involved in the pathogenesis of diabetic complications such as angiogenesis, extracellular matrix deposition, and inflammation. However, no data on circulating microRNA-191-5p in the chronic complications of diabetes are available.

OBJECTIVE

To assess whether serum levels of microRNA-191-5p were associated with micro- and macrovascular disease in a large cohort of subjects with type 1 diabetes mellitus (DM1) from the EURODIAB Prospective Complication Study.

DESIGN AND SETTING

Levels of microRNA-191-5p were measured by quantitative PCR in 420 patients with DM1 recruited as part of the cross-sectional analysis of the EURODIAB Prospective Complication Study. Cases (n = 277) were subjects with nephropathy and/or retinopathy and/or cardiovascular disease (CVD). Controls (n = 143) were patients without complications. Logistic regression analysis was performed to evaluate the potential independent association of microRNA-191-5p levels with chronic complications of diabetes.

RESULTS

Levels of microRNA-191-5p were significantly reduced (P < .001) in cases compared with controls even after adjustment for age, sex, and diabetes duration. Logistic regression analysis revealed that microRNA-191-5p was negatively associated with a 58% reduced odds ratio (OR) of chronic diabetes complications, specifically CVD, micro-macroalbuminuria, and retinopathy (OR, 0.42; 95% CI, 0.23-0.77), independent of age, sex, physical activity, educational levels, diabetes duration, glycated hemoglobin, total insulin dose, hypertension, smoking, total cholesterol, albumin excretion rate, estimated glomerular filtration rate, serum vascular cell adhesion molecule-1, and tumor necrosis factor-α. Analyses performed separately for each complication demonstrated a significant independent association with albuminuria (OR, 0.36; 95% CI, (0.18-0.75) and CVD (OR, 0.34; 95% CI, 0.16-0.70).

CONCLUSIONS

In DM1 subjects, microRNA-191-5p is inversely associated with vascular chronic complications of diabetes.

The MEK-ERK-Egr-1 axis and its regulation in cardiovascular disease

Cardiovascular disease (CVD) is the primary cause of morbidity and mortality in the Western world. Multiple molecular and cellular processes underpinning the pathogenesis of CVD are regulated by the zinc finger transcription factor and product of an immediate-early gene, early growth response-1 (Egr-1). Egr-1 regulates multiple pro-inflammatory processes that underpin the manifestation of CVD. The activity of Egr-1 itself is influenced by a range of post-translational modifications including sumoylation, ubiquitination and acetylation. Egr-1 also undergoes phosphorylation by protein kinases, such as extracellular-signal regulated kinase (ERK) which is itself phosphorylated by MEK. This article reviews recent progress on the MEK-ERK-Egr-1 cascade, notably regulation in conjunction with factors and agents such as TET2, TRIB2, MIAT, SphK1, cAMP, teneligliptin, cholinergic drugs, red wine and flavonoids, wogonin, febuxostat, docosahexaenoic acid and AT1R blockade. Such insights should provide new opportunity for therapeutic intervention in CVD.

Transcriptional regulation of vascular smooth muscle cell proliferation, differentiation and senescence: Novel targets for therapy

Vascular smooth muscle cells (SMC) possess a unique cytoplasticity, regulated by transcriptional, translational and phenotypic transformation in response to a diverse range of extrinsic and intrinsic pathogenic factors. The mature, differentiated SMC phenotype is physiologically typified transcriptionally by expression of genes encoding "contractile" proteins, such as SMα-actin (ACTA2), SM-MHC (myosin-11) and SM22α (transgelin). When exposed to various pathological conditions (e.g., pro-atherogenic risk factors, hypertension), SMC undergo phenotypic modulation, a bioprocess enabling SMC to de-differentiate in immature stages or trans-differentiate into other cell phenotypes. As recent studies suggest, the process of SMC phenotypic transformation involves five distinct states characterized by different patterns of cell growth, differentiation, migration, matrix protein expression and declined contractility. These changes are mediated via the action of several transcriptional regulators, including myocardin and serum response factor. Conversely, other factors, including Kruppel-like factor 4 and nuclear factor-κB, can inhibit SMC differentiation and growth arrest, while factors such as yin yang-1, can promote SMC differentiation whilst inhibiting proliferation. This article reviews recent advances in our understanding of regulatory mechanisms governing SMC phenotypic modulation. We propose the concept that transcription factors mediating this switching are important biomarkers and potential pharmacological targets for therapeutic intervention in cardiovascular disease.

Early Growth Response-1, an Integrative Sensor in Cardiovascular and Inflammatory Disease

Early growth response‐1 (Egr‐1) is a master regulator and transcriptional sensor in vascular dysfunction and disease. This article reviews recent developments in our understanding of the regulatory roles this zinc finger protein and product of an immediate‐early gene plays in a range of cardiovascular and inflammatory disorders. Egr‐1 can amplify pathologic signals from the extracellular environment by serving as a molecular conduit in the inducible expression of proliferative, migratory and proinflammatory genes driving disease progression. Strategies targeting Egr‐1 may provide therapeutic benefit in cardiovascular and inflammatory disorders.

miR-30e-3p Promotes Cardiomyocyte Autophagy and Inhibits Apoptosis via Regulating Egr-1 during Ischemia/Hypoxia

Background

Microvascular obstruction (MVO) can result in coronary microcirculation embolism and myocardial microinfarction. Myocardial injury induced by MVO is characterized by continuous ischemia and hypoxia of cardiomyocytes. Autophagy and apoptosis are closely associated with various cardiovascular diseases. Based on our previous study, we observed a decrease in miR-30e-3p expression and an increase in Egr-1 expression in a rat coronary microembolization model. However, the specific function of miR-30e-3p in regulating autophagy and apoptosis in an ischemia/hypoxia (IH) environment remains to be deciphered. We exposed cardiomyocytes to an IH environment and then determined whether miR-30e-3p was involved in promoting cardiomyocyte autophagy and inhibiting apoptosis by regulating Egr-1.

Methods

Cardiomyocytes were isolated from rats for our in vitro study. miR-30e-3p was either overexpressed or inhibited by transfection with lentiviral vectors into cardiomyocytes. 3-Methyladenine (3-MA) was used to inhibit autophagy. RT-qPCR and western blotting were used to determine the expression levels of miR-30e-3p, Egr-1, and proteins related to the autophagy and apoptosis process. Autophagic vacuoles and autophagic flux were evaluated using transmission electron microscopy (TEM) and confocal microscopy, respectively. Cardiomyocyte viability was evaluated using the MTS assay. Cell injury was assessed by lactate dehydrogenase (LDH) leakage, and apoptosis was determined by flow cytometry.

Results

Both miR-30e-3p expression and autophagy were significantly inhibited, and apoptosis was increased in cardiomyocytes after 9 hours of IH exposure. Overexpression of miR-30e-3p increased autophagy and inhibited apoptosis, as well as suppressed Egr-1 expression and decreased cell injury. In addition, inhibition of miR-30e-3p reduced autophagy and increased apoptosis and cell injury.

Conclusions

miR-30e-3p may be involved in promoting cardiomyocyte autophagy and inhibiting apoptosis by indirectly regulating Egr-1 expression in an IH environment.

Transcription Factors Targeted by miRNAs Regulating Smooth Muscle Cell Growth and Intimal Thickening after Vascular Injury

Neointima formation after percutaneous coronary intervention (PCI) is a manifestation of “phenotype switching” by vascular smooth muscle cells (SMC), a process that involves de-differentiation from a contractile quiescent phenotype to one that is richly synthetic. In response to injury, SMCs migrate, proliferate, down-regulate SMC-specific differentiation genes, and later, can revert to the contractile phenotype. The vascular response to injury is regulated by microRNAs (or miRNAs), small non-coding RNAs that control gene expression. Interactions between miRNAs and transcription factors impact gene regulatory networks. This article briefly reviews the roles of a range of miRNAs in molecular and cellular processes that control intimal thickening, focusing mainly on transcription factors, some of which are encoded by immediate-early genes. Examples include Egr-1, junB, KLF4, KLF5, Elk-1, Ets-1, HMGB1, Smad1, Smad3, FoxO4, SRF, Rb, Sp1 and c-Myb. Such mechanistic information could inform the development of strategies that block SMC growth, neointima formation, and potentially overcome limitations of lasting efficacy following PCI.

Suppression of HSP70 inhibits the development of acute lymphoblastic leukemia via TAK1/Egr-1

Acute lymphoblastic leukemia (ALL), usually treated with chemotherapy, has limited therapeutic effects and high toxicity. Upregulation of HSP70 induces tumor development, however, the molecular mechanism of HSP70 in ALL remains unclear. In our research, we aimed to investigate the role of HSP70 in ALL, specifically the molecular mechanisms underlying cell apoptosis and proliferation. We found that HSP70 expression in leukomonocytes from ALL patients was increased compared with the control group. HSP70 expression in NALM-6 and BE-13 was also up-regulated contrast with AHH-1. Inhibition of HSP70 significantly promoted cell apoptosis and suppressed cell proliferation in ALL cell lines. Suppression of HSP70 decreased TAK1 and increased Egr-1 protein expression. Further experiments indicated that overexpression of TAK1 ameliorated the effect of HSP70 inhibition on Egr-1 protein expression, cell apoptosis and proliferation. In order to determine whether the effect of HSP70 inhibition on apoptosis and proliferation of ALL cell lines could be achieved via regulation of Egr-1, we performed a loss-of-function experiment for Egr-1. Egr-1 suppression was found to reverse the effect of HSP70 inhibition on cell apoptosis and proliferation in ALL. Taken together, our results suggest that HSP70 inhibition upregulates Egr-1 via TAK1, inducing apoptosis and restricting proliferation in ALL cells.

Suppressing serum response factor inhibits invasion in cervical cancer cell lines via regulating Egr‑1 and epithelial-mesenchymal transition

Serum response factor (SRF) is a transcription factor that has important roles in tumor progression. However, its role in cervical cancer cell proliferation and invasion remains unclear. The present study revealed that SRF silencing constrained cervical cancer cell proliferation and invasion via controlling early growth response‑1 (Egr‑1). The results demonstrated that SRF was significantly increased in cervical cancer tissues and cell lines, compared with normal. Suppressing SRF, by using a loss‑of‑function experiment, constrained cervical cancer cell proliferation, invasion, and epithelial‑mesenchymal transition. Furthermore, SRF knockdown significantly downregulated Egr‑1 expression in cervical cancer cell lines, and overexpression of Egr‑1 reversed the effect of SRF on cell proliferation, invasion, and epithelial‑mesenchymal transition. Therefore, SRF may control cell proliferation and invasion by regulating Egr‑1 in cervical cancer.

Circulating microRNAs, Vascular Risk, and Physical Activity in Spinal Cord-Injured Subjects

The aim of this study was to compare the expression of serum microRNAs (miRNAs) in individuals with spinal cord injury (SCI) (athletes [SCI-A] and sedentary [SCI-S]) and able-bodied (AB) individuals, and investigate the relationship of miRNAs with carotid intima-media thickness (cIMT) and serum oxidized LDL-cholesterol (oxLDL) among SCI subjects. Seventeen SCI-S, 23 SCI-A, and 22 AB males were evaluated by clinical and laboratory analysis, and had oxLDL and cIMT measured by enzyme-linked immunosorbent assay (ELISA) and ultrasonography, respectively. A total of 754 miRNAs were measured using a TaqMan OpenArray^® Human MicroRNA system. SCI-S subjects had higher cIMT and oxLDL than SCI-A and AB. Compared with AB, only one miRNA was differently expressed in both SCI-A and SCI-S individuals, whereas 25 miRNAs were differently expressed in SCI-S, but not in SCI-A. Of these 25 miRNAs, 22 showed different expression between SCI-S and SCI-A. Several miRNAs correlated with oxLDL and cIMT among all SCI individuals. Notably, miR-125b-5p, miR-146a-5p, miR-328-3p, miR-191-5p, miR-103a-3p, and miR-30b-5p correlated with both oxLDL and cIMT, and showed distinct expression between the SCI-A and SCI-S groups. Gene set enrichment analysis demonstrated that miRNAs related to cIMT and oxLDL may be involved in molecular pathways regulating vascular function and remodeling. In conclusion, this exploratory analysis suggests that variations in circulating miRNA expression in individuals with SCI compared with AB subjects are markedly attenuated by regular physical activity. Several miRNAs may be involved in physical activity-related improvements in vascular risk and remodeling among SCI individuals.

Hypoxia-induced microRNA-191 contributes to hepatic ischemia/reperfusion injury through the ZONAB/Cyclin D1 axis

Hepatic ischemia/reperfusion injury (IRI) is a common cause of morbidity and mortality in liver transplantation settings and involves severe cell death and inflammatory responses. MicroRNA-191 has recently been reported to be abnormally expressed in hepatocellular carcinoma and other liver diseases in the regulation of important cellular processes. However, little is known about its function and molecular mechanism in IRI. Here, we demonstrate that miR-191 is significantly upregulated in a cultured cell line during hypoxia/reperfusion (H/R) and in liver tissue during IRI in mice. The activation of miR-191 under hypoxic conditions is mediated by hypoxia-inducible factor-1α (HIF1α) binding to its promoter region. Global miR-191 KO mice were constructed by CRISPR/Cas9 system, and we found that miR-191 deficiency markedly reduces liver tissue damage, cell inflammatory responses and cell death in a mouse hepatic IRI model. Under the H/R condition, miR-191 overexpression promotes G0/G1 cell cycle arrest and cell apoptosis, but inhibition of miR-191 facilitates cell cycle progression and decreases cell death. Mechanistically, upon induction by hypoxia or ischemia, miR-191 suppresses expression of ZO-1-associated Y-box factor (ZONAB) and its downstream factor Cyclin D1, consequently resulting in cell death and tissue injury. Moreover, the effects of miR-191 on cell cycle arrest and cell apoptosis are abrogated by ZONAB overexpression, and vice versa. Taken together, our results indicate an important role of the HIF1α/miR-191/ZONAB signaling pathway in hepatic IRI and suggest miR-191 as a novel therapeutic target for the treatment of liver IRI.

β1-Integrin Deletion From the Lens Activates Cellular Stress Responses Leading to Apoptosis and Fibrosis

Purpose

Previous research showed that the absence of β1-integrin from the mouse lens after embryonic day (E) 13.5 (β1MLR10) leads to the perinatal apoptosis of lens epithelial cells (LECs) resulting in severe microphthalmia. This study focuses on elucidating the molecular connections between β1-integrin deletion and this phenotype.

Methods

RNA sequencing was performed to identify differentially regulated genes (DRGs) in β1MLR10 lenses at E15.5. By using bioinformatics analysis and literature searching, Egr1 (early growth response 1) was selected for further study. The activation status of certain signaling pathways (focal adhesion kinase [FAK]/Erk, TGF-β, and Akt signaling) was studied via Western blot and immunohistochemistry. Mice lacking both β1-integrin and Egr1 genes from the lenses were created (β1MLR10/Egr1^−/−) to study their relationship.

Results

RNA sequencing identified 120 DRGs that include candidates involved in the cellular stress response, fibrosis, and/or apoptosis. Egr1 was investigated in detail, as it mediates cellular stress responses in various cell types, and is recognized as an upstream regulator of numerous other β1MLR10 lens DRGs. In β1MLR10 mice, Egr1 levels are elevated shortly after β1-integrin loss from the lens. Further, pErk1/2 and pAkt are elevated in β1MLR10 LECs, thus providing the potential signaling mechanism that causes Egr1 upregulation in the mutant. Indeed, deletion of Egr1 from β1MLR10 lenses partially rescues the microphthalmia phenotype.

Conclusions

β1-integrin regulates the appropriate levels of Erk1/2 and Akt phosphorylation in LECs, whereas its deficiency results in the overexpression of Egr1, culminating in reduced cell survival. These findings provide insight into the molecular mechanism underlying the microphthalmia observed in β1MLR10 mice.

The microRNA miR-124 inhibits vascular smooth muscle cell proliferation by targeting S100 calcium-binding protein A4 (S100A4)

S100 calcium-binding protein A4 (S100A4) induces proliferation and migration of vascular smooth muscle cells (VSMCs). We aimed to find the microRNA regulating S100A4 expression. S100A4 transcripts are abruptly increased in the acute phase of carotid arterial injury 1 day later (at day 1) but gradually decreases at days 7 and 14. Bioinformatics analysis reveals that miR-124 targets S100A4. VSMC survival is attenuated by miR-124 mimic but increased by miR-124 inhibitor. miR-124 decreases immediately after carotid arterial injury but dramatically increases at days 7 and 14. miR-124 inhibitor-induced cell proliferation is blocked by S100A4 siRNA, whereas miR-124-induced cell death is recovered by S100A4. Our findings suggest that miR-124 is a novel regulator of VSMC proliferation and may play a role in the development of neointimal proliferation.

Early growth response-1 in the pathogenesis of cardiovascular disease

This article reviews the regulatory roles of the immediate-early gene product and prototypic zinc finger transcription factor, early growth response-1 in models of cardiovascular pathobiology, focusing on insights using microRNA, DNAzymes, small hairpin RNA, small interfering RNA, oligonucleotide decoy strategies and mice deficient in early growth response-1.