Estrogen receptor-mediated regulation of microRNA inhibits proliferation of vascular smooth muscle cells

MicroRNAs regulate the vicious cycle of vascular calcification-osteoporosis in postmenopausal women

Menopause is a normal physiological process accompanied by changes in various physiological states. The incidence of vascular calcification (VC) increases each year after menopause and is closely related to osteoporosis (OP). Although many studies have investigated the links between VC and OP, the interaction mechanism of the two under conditions of estrogen loss remains unclear. MicroRNAs (miRNAs), which are involved in epigenetic modification, play a critical role in estrogen-mediated mineralization. In the past several decades, miRNAs have been identified as biomarkers or therapeutic targets in diseases. Thus, we hypothesize that these small molecules can provide new diagnostic and therapeutic approaches. In this review, we summarize the close interactions between VC and OP and the role of miRNAs in their interplay.

Estrogen-mediated oar-miR-485-5p targets PPP1R13B to regulate myoblast proliferation in sheep

Ovaries are important endocrine organs in female animals that secrete various steroid hormones, which are involved in multiple physiological functions. Estrogen, one of the hormones secreted by ovaries, is essential for the overall maintenance of muscle growth and development. However, the molecular mechanisms that affect muscle growth and development in sheep following ovariectomy remain unclear. In this study, we identified 1662 differentially expressed mRNAs (DEGs) and 40 differentially expressed miRNAs (DEMs) in sheep that underwent ovariectomy compared with those that underwent sham surgery. A total of 178 DEG-DEM pairs were negatively correlated. GO and KEGG analysis showed that PPP1R13B was involved in the PI3K-Akt signaling pathway, which was essential for muscle development. Using in vitro experiments, we examined the effect of PPP1R13B on myoblast proliferation and found that overexpression or inhibition of PPP1R13B increased or decreased the expression of myoblast proliferation markers, respectively. PPP1R13B was identified as a functional downstream target of miR-485-5p. Our results suggested that miR-485-5p promoted myoblast proliferation by regulating proliferation factors in myoblasts by targeting PPP1R13B. Notably, exogenous estradiol supplementation to myoblasts regulated the expression of oar-miR-485-5p and PPP1R13B and promoted myoblast proliferation. These results provided new insights into the molecular mechanism by which ovaries influence muscle growth and development in sheep.

Modulation of Vascular Smooth Muscle Cell Multiplication, Apoptosis, and Inflammatory Damage by miR-21 in Coronary Heart Disease

This study is aimed at exploring the role and potential molecular mechanism of microRNA-21 (miR-21) in coronary heart disease (CHD). RT-qPCR analysis was conducted to detect the expression of miR-21, Sprouty 1 (SPRY1), and connexin 43 (CX43). The protein expression of SPRY1 and CX43 was measured by western blot. ELISA was performed for measuring inflammatory factors, including intercellular adhesion molecule-1 (ICAM-1) and interleukin-1 beta (IL-1β). The target relationship between miR-21 and SPRY1 was determined by dual-luciferase reporter assay. Cell multiplication and apoptosis were detected using CCK-8 assay and flow cytometry analysis, respectively. Our results indicated that miR-21, CX43, and the level of inflammatory cytokines including ICAM-1 and IL-1β were upregulated, while SPRY1 was downregulated in blood samples from CHD patients compared with the controls. Besides, miR-21 directly targeted SRPY-1. miR-21 could suppress SPRY1 expression and enhance CX43 expression in VSMCs. Moreover, miR-21 accelerated cell multiplication and attenuated cell apoptosis in VSMCs. Collectively, these findings suggested that miR-21 could effectively elevate VSMC multiplication and repress apoptosis by targeting SPRY1 in CHD, providing a potential target for therapeutic strategy of CHD.

Association of Reproductive Lifespan Duration and Chronic Kidney Disease in Postmenopausal Women

OBJECTIVE

To investigate the relationship between endogenous estrogen exposure and renal function, the association of female reproductive life span duration (RLD) and chronic kidney disease (CKD) was analyzed in postmenopausal women.

PATIENTS AND METHODS

Data were retrieved from the Korean Genome and Epidemiology Study, which was constructed from May 1, 2001, through December 25, 2017. A total of 50,338 and 3155 postmenopausal women were each included in the cross-sectional and longitudinal analyses. The RLD was determined by subtracting the age at menarche from the age at menopause. Participants were grouped into RLD quartiles. Participants with estimated glomerular filtration rates less than 60 mL/min/1.73 m² were regarded to have CKD.

RESULTS

In the cross-sectional analysis, mean ± SD age and estimated glomerular filtration rate were 56.3±4.9 years and 93.1±13.6 mL/min/1.73 m², respectively. Mean ± SD RLD was 34.2±4.0 years. A total of 765 of 50,338 (1.52%) women were found to have CKD. Logistic regression analysis revealed that the odds ratio for CKD was lower in groups with longer RLDs as compared with the shortest RLD group. In longitudinal analysis, postmenopausal women with normal kidney function were followed up for 9.7 years and incident CKD occurred in 221 of 3155 (7.00%) participants. Cox analysis revealed that the risk for CKD development was significantly lower in longer RLD groups. This finding was significant even after adjustments for confounding factors.

CONCLUSION

The risk for CKD was lower in women with longer RLDs. The amount of endogenous estrogen exposure could be a determining factor for renal function in postmenopausal women.

Inhibition of miR-203 Ameliorates Osteoarthritis Cartilage Degradation in the Postmenopausal Rat Model: Involvement of Estrogen Receptor α

miR-203 is known to target estrogen receptor α (ERα) in various cancer cell lines, such as MCF-7. However, whether miR-203 regulates ERα and contributes to the onset and progression of osteoarthritis (OA) is poorly understood. A combined protocol of the bilateral ovariectomy and the intra-articular monosodium iodoacetate injection was applied to establish a postmenopausal OA model in rats. Real-time quantitative polymerase chain reaction was used to detect miR-203 and mRNAs and Western blotting was exploited to quantify the expression levels on the protein level. Enzyme-linked immunosorbent assays were deployed to detect the expression of matrix metalloproteinase-1 (MMP-1), MMP-3, prostaglandin E₂ (PGE₂), and collagen type II degradation (CTX-II) in serum samples. Dual-luciferase reporter assay was utilized to confirm the direct binding of miR-203 on ERα in postmenopausal OA rats. Expression of miR-203 was elevated; while ERα mRNA and protein were downregulated in postmenopausal OA rats, compared with sham rats. Dual-luciferase reporter assay confirmed miR-203 bound and negatively regulated ERα, resulting in promoted cellular inflammation and cartilage destruction in postmenopausal OA rats. Suppression of miR-203 using a specific inhibitor ameliorated cartilage degradation in postmenopausal OA rats. miR-203 is pivotal in the onset and progression of OA in the postmenopausal rat model, and holds promise for a therapeutic target of OA treatment.

MiR-203 regulates estrogen receptor α and cartilage degradation in IL-1β-stimulated chondrocytes

INTRODUCTION

Estrogen receptor α (ERα) plays important roles in the etiology of osteoarthritis (OA), in which cartilage degradation and cellular inflammation are involved. MiR-203 is reported to direct target ERα, but its roles in chondrocytes remain uncovered.

METHODS

In this study, ELISA showed that the level of estrogen hormone in the serum of postmenopausal OA patients was significantly lower than the one in patients without OA. RT-PCR revealed that the expression level of miR-203 was significantly up-regulated in the OA patients. Furthermore, western blotting demonstrated the lower expression levels of aggrecan, Col2A1, and ERα in the isolated articular cartilage tissues of OA patients. To decipher the association between ERα and miR-203 in the pathogenesis of OA, IL-1β stimulated cultured chondrocyte cell model was established to measure the cell viability, cellular inflammation, cell injury, as well as cartilage degradation with miR-203 inhibitor and ERα.

RESULTS

The results showed that IL-1β stimulation induced the expression of miR-203, which promoted cellular inflammation and cell injury, and caused down-regulation of aggrecan and Col2A1. Luciferase assay indicated the direct binding between miR-203 and ERα, and ERα-specific SiRNA inversed the protective role of miR-203 inhibitor in the progression of OA in the cell system.

CONCLUSIONS

MiR-203 is critical in the onset and progression of OA, at least in part, caused by estrogen deficiency and ERα instability in OA patients, providing a novel therapeutic target for the treatment of OA.

Short-term aromatase inhibition induces prostatic alterations in adult wistar rat: A biochemical, histopathological and immunohistochemical study

PURPOSE

This study aimed to evaluate the effects of estrogen reduction on amyloid deposition, some lipid metabolism and oxidative stress markers, PSA-like production and p63 expression in the prostate of the adult rat.

METHODS

Aromatase inhibitor: Formestane (4-OHA), was administrated to male rats, at a dose of 0.1 mg/kg b.w./day, for 10 days. The control group (CONT) received the same volume of placebo injection (NaCl 0.9%).

RESULTS

4-OHA treatment induced a significant accumulation of intraprostatic cholesterol (138.90 ± 17.64 vs 85.12 ± 2.87, p = 0.01); against an insignificant diminution of malondialdehyde (412.6 ± 54.35 vs 842.70 ± 336.50, p > 0.05) and glutathione (2.40 ± 0.23 vs 3.65 ± 0.88, p > 0.05). This was associated with a significant decrease of nitric oxide (31.76 ± 7.07 vs 179.40 ± 58.35, p = 0.024). Additionally, 4-OHA significantly increased the intraprostatic production of PSA-like (11.12 ± 2.78 vs 3.91 ± 0.43, p = 0.043). The prostatic histology revealed an amyloid deposition, in all prostatic lobes and a smooth muscle layer growth (p < 0.05); especially significant in the dorsal and lateral lobes. Theses lobes manifested a basal cells proliferation, with a 3-fold increase of p63 expression (p < 0.001). The ventral lobe presented epithelial atrophy (37.80 ± 16.20 vs 167.60 ± 5.16, p < 0.05); with occasional and significant proliferative foci (247.00 ± 9.573 vs 167.60 ± 5.16 p < 0.05).

DISCUSSION AND CONCLUSION

Aromatase inhibition, in the adult male rat, alters the prostatic function by reducing nitric oxide availability and inducing amyloid deposition along with limiting the differentiation of basal cells, through a lobe-specific p63-overexpression.

Cardiomyopathy Associated with Diabetes: The Central Role of the Cardiomyocyte

The term diabetic cardiomyopathy (DCM) labels an abnormal cardiac structure and performance due to intrinsic heart muscle malfunction, independently of other vascular co-morbidity. DCM, accounting for 50%–80% of deaths in diabetic patients, represents a worldwide problem for human health and related economics. Optimal glycemic control is not sufficient to prevent DCM, which derives from heart remodeling and geometrical changes, with both consequences of critical events initially occurring at the cardiomyocyte level. Cardiac cells, under hyperglycemia, very early undergo metabolic abnormalities and contribute to T helper (Th)-driven inflammatory perturbation, behaving as immunoactive units capable of releasing critical biomediators, such as cytokines and chemokines. This paper aims to focus onto the role of cardiomyocytes, no longer considered as “passive” targets but as “active” units participating in the inflammatory dialogue between local and systemic counterparts underlying DCM development and maintenance. Some of the main biomolecular/metabolic/inflammatory processes triggered within cardiac cells by high glucose are overviewed; particular attention is addressed to early inflammatory cytokines and chemokines, representing potential therapeutic targets for a prompt early intervention when no signs or symptoms of DCM are manifesting yet. DCM clinical management still represents a challenge and further translational investigations, including studies at female/male cell level, are warranted.

Long noncoding RNA LINC00968 promotes endothelial cell proliferation and migration via regulating miR-9-3p expression

Long noncoding RNAs (lncRNAs) have been showed to play a crucial role in pathogenesis and development of cardiovascular diseases. Our study aimed to study the expression and functional role of lncRNA LINC00968 in the development of coronary artery disease (CAD). We showed that the LINC00968 expression level was upregulated in the CAD tissues compared with normal arterial tissues. In addition, we showed that the expression level of LINC00968 was upregulated by oxidized low-density lipoprotein (oxLDL) treatment in endothelial cell. Ectopic expression of LINC00968 regulated the proliferation and migration of endothelial cell. Moreover, we showed that overexpression of LINC00968 inhibited miR-9-3p expression in an endothelial cell. Furthermore, we demonstrated that the miR-9-3p expression was downregulated in the CAD samples compared with normal arterial tissues and the expression level of miR-9-3p was downregulated by oxLDL treatment in endothelial cell. Finally, we showed that ectopic expression of LINC00968 promoted endothelial cell proliferation and migration partly through regulating miR-9-3p expression. These results suggested that LINC00968 plays a crucial role in the progression of the CAD.

Role of miRNA in the Regulatory Mechanisms of Estrogens in Cardiovascular Ageing

Cardiovascular diseases are a worldwide health problem and are the leading cause of mortality in developed countries. Together with experimental data, the lower incidence of cardiovascular diseases in women than in men of reproductive age points to the influence of sex hormones at the cardiovascular level and suggests that estrogens play a protective role against cardiovascular disease and that this role is also modified by ageing. Estrogens affect cardiovascular function via their specific estrogen receptors to trigger gene expression changes at the transcriptional level. In addition, emerging studies have proposed a role for microRNAs in the vascular effects mediated by estrogens. miRNAs regulate gene expression by repressing translational processes and have been estimated to be involved in the regulation of approximately 30% of all protein-coding genes in mammals. In this review, we highlight the current knowledge of the role of estrogen-sensitive miRNAs, and their influence in regulating vascular ageing.

Diabetic Cardiomyopathy: Impact of Biological Sex on Disease Development and Molecular Signatures

Diabetic cardiomyopathy refers to a unique set of heart-specific pathological variables induced by hyperglycemia and insulin resistance. Given that cardiovascular disease (CVD) is the leading cause of death in the world, and type 2 diabetes incidence continues to rise, understanding the complex interplay between these two morbidities and developing novel therapeutic strategies is vital. Two hallmark characteristics specific to diabetic cardiomyopathy are diastolic dysfunction and cardiac structural mal-adaptations, arising from cardiac cellular responses to the complex toxicity induced by hyperglycemia with or without hyperinsulinemia. While type 2 diabetes is more prevalent in men compared to women, cardiovascular risk is higher in diabetic women than in diabetic men, suggesting that diabetic women take a steeper path to cardiomyopathy and heart failure. Accumulating evidence from randomized clinical trials indicate that although pre-menopausal women have lower risk of CVDs, compared to age-matched men, this advantage is lost in diabetic pre-menopausal women, which suggests estrogen availability does not protect from increased cardiovascular risk. Notably, few human studies have assessed molecular and cellular mechanisms regarding similarities and differences in the progression of diabetic cardiomyopathy in men versus women. Additionally, most pre-clinical rodent studies fail to include female animals, leaving a void in available data to truly understand the impact of biological sex differences in diabetes-induced dysfunction of cardiovascular cells. Elegant reviews in the past have discussed in detail the roles of estrogen-mediated signaling in cardiovascular protection, sex differences associated with telomerase activity in the heart, and cardiac responses to exercise. In this review, we focus on the emerging cellular and molecular markers that define sex differences in diabetic cardiomyopathy based on the recent clinical and pre-clinical evidence. We also discuss miR-208a, MED13, and AT2R, which may provide new therapeutic targets with hopes to develop novel treatment paradigms to treat diabetic cardiomyopathy uniquely between men and women.

Anti-miR-203 suppresses ER-positive breast cancer growth and stemness by targeting SOCS3

Breast cancer is a major public health problem worldwide in women and existing treatments are not adequately effective for this deadly disease. microRNAs (miRNAs) regulate the expression of many target genes and play pivotal roles in the development, as well as in the suppression of many cancers including breast cancer. We previously observed that miR-203 was highly upregulated in breast cancer tissues and in ER-positive breast cancer cell lines. In our present study, we observed that anti-miR-203 suppresses breast cancer cell proliferation in vitro. Orthotopic implantation of miR-203 depleted MCF-7 cells into nude mice displays smaller tumor growth as compared to control MCF-7 cells. Furthermore, miR-203 expression is significantly higher in ER-positive breast cancer patients as compared to ER-negative patients. We identified suppressor of cytokine signaling 3 (SOCS3) as a direct target of miR-203. Here we observed that miR-203 expression is inversely correlated with SOCS3 expression in ER-positive breast cancer samples. Additionally, we found that anti-miR-203 suppressed the expression of pStat3, pERK and c-Myc in MCF-7 and ZR-75-1 cells. We also demonstrated that anti-miR-203 decreased mammospheres formation and expression of stem cell markers in MCF-7 and ZR-75-1 cells. Taken together, our data suggest that anti-miR-203 has potential as a novel therapeutic strategy in ER-positive breast cancer treatment.

miRNA as a New Regulatory Mechanism of Estrogen Vascular Action

The beneficial effects of estrogen on the cardiovascular system have been reported extensively. In fact, the incidence of cardiovascular diseases in women is lower than in age-matched men during their fertile stage of life, a benefit that disappears after menopause. These sex-related differences point to sexual hormones, mainly estrogen, as possible cardiovascular protective factors. The regulation of vascular function by estrogen is mainly related to the maintenance of normal endothelial function and is mediated by both direct and indirect gene transcription through the activity of specific estrogen receptors. Some of these mechanisms are known, but many remain to be elucidated. In recent years, microRNAs have been established as non-coding RNAs that regulate the expression of a high percentage of protein-coding genes in mammals and are related to the correct function of human physiology. Moreover, within the cardiovascular system, miRNAs have been related to physiological and pathological conditions. In this review, we address what is known about the role of estrogen-regulated miRNAs and their emerging involvement in vascular biology.

Cardiovascular Risk Factors and Markers

Cardiovascular risk is assessed for the prediction and appropriate management of patients using collections of identified risk markers obtained from clinical questionnaire information, concentrations of certain blood molecules (e.g., N-terminal proB-type natriuretic peptide fragment and soluble receptors of tumor-necrosis factor-α and interleukin-2), imaging data using various modalities, and electrocardiographic variables, in addition to traditional risk factors.

Gender and cardiovascular disease: are sex-biased microRNA networks a driving force behind heart failure with preserved ejection fraction in women?

Cardiovascular disease (CVD) is the primary cause of death among men and women worldwide. Nevertheless, our comprehension of how CVD progresses in women and elicits clinical outcomes is lacking, leading CVD to be under-diagnosed and under-treated in women. A clear example of this differential presentation of CVD pathophysiologies in females is the strikingly higher prevalence of heart failure with preserved ejection fraction (HFpEF). Women with a history of pre-eclampsia or those who present with co-morbidities such as obesity, hypertension, and diabetes mellitus are at increased risk of developing HFpEF. Long understood to be a critical CVD risk factor, our understanding of how gender differentially affects the development of CVD has been greatly expanded by extensive genomic and transcriptomic studies. These studies uncovered a pivotal role for differential microRNA (miRNA) expression in response to systemic inflammation, where their co-ordinated expression forms a post-transcriptional regulatory network that instigates microcirculation defects. Importantly, the potential sex-biased expression of the given miRNAs may explain sex-specific cardiovascular pathophysiologies in women, such as HFpEF. Sex-biased miRNAs are regulated by oestrogen (E2) in their transcription and processing or are expressed from loci on the X-chromosome due to incomplete X-chromosome inactivation. Interestingly, while E2-induced miRNAs predominantly appear to serve protective functions, it could be argued that many X-linked miRNAs have been found to challenge microvascular and myocardial integrity. Therefore, menopausal E2 deficiency, resulting in protective miRNA loss, and the augmentation of X-linked miRNA expression, may well contribute to the molecular mechanisms that underlie the female-specific cardiovascular aetiology in HFpEF.

miR-503 inhibits platelet-derived growth factor-induced human aortic vascular smooth muscle cell proliferation and migration through targeting the insulin receptor

Abnormal proliferation and migration of vascular smooth muscle cells (VSMC) is a common feature of disease progression in atherosclerosis. Here, we investigated the potential role of miR-503 in platelet-derived growth factor (PDGF)-induced proliferation and migration of human aortic smooth muscle cells and the underlying mechanisms of action. miR-503 expression was significantly downregulated in a dose- and time-dependent manner following PDGF treatment. Introduction of miR-503 mimics into cultured SMCs significantly attenuated cell proliferation and migration induced by PDGF. Bioinformatics analyses revealed that the insulin receptor (INSR) is a target candidate of miR-503. miR-503 suppressed luciferase activity driven by a vector containing the 3'-untranslated region of INSR in a sequence-specific manner. Downregulation of INSR appeared critical for miR-503-mediated inhibitory effects on PDGF-induced cell proliferation and migration in human aortic SMCs. Based on the collective data, we suggest a novel role of miR-503 as a regulator of VSMC proliferation and migration through modulating INSR.

GPR30 decreases with vascular aging and promotes vascular smooth muscle cells maintaining differentiated phenotype and suppressing migration via activation of ERK1/2

Estrogen receptors, including classic nuclear receptors ERα, ERβ, and membrane receptor GPR30, are expressed in vascular tissues and exert protective actions in vascular diseases. But the expression pattern and functional roles of GPR30 in vascular smooth muscle cells (VSMCs) remain unclear. In this study, we found that ERα, ERβ, and GPR30 were decreased with VSMCs passaging in vitro or growing in vivo and activation of GPR30 promoted ERα expression. Then, we validated that activation of GPR30 significantly decreased migratory capability of VSMCs and suppressed ERα, whereas PDGF-BB (20 ng/mL) treatment caused increase of migration. And activation of GPR30 led to reduction of osteopontin and cellular retinol binding protein 1, enhancement of calponin and 3F8, and upregulation of total and phosphorylated ERK1/2 expression in VSMCs knocked down by GPR30, ERα, and ERβ or treated with PDGF-BB. These data suggest that GPR30 promotes VSMCs reducing migration and maintaining differentiated phenotype via activation of ERK1/2 pathway. Our findings provide novel mechanisms of GPR30 protection of VSMCs as well as a new target for prevention of vascular aging.

Xiaoxianggou attenuates atherosclerotic plaque formation in endogenous high Ang II ApoE(-/-) mice via the inhibition of miR-203 on the expression of Ets-2 in endothelial cells

BACKGROUND

Atherosclerosis is a chronic immune-inflammatory disorder and one of the leading causes responsible for cardiovascular morbidity and mortality. Traditional Chinese medicine treatment with multi-targets has shown prospects for the therapeutic effect on atherosclerosis. Thus, this study aims to investigate whether xiaoxianggou has benefit for reducing the atherosclerotic plaque area in endogenous high Ang II ApoE(-/-) mice and investigated the underlying mechanisms.

METHODS

Endogenous high Ang II ApoE(-/-) mice model was generated by using two kidney one clip (2K1C). All mice were treated by intragastric administration with xiaoxianggou two times a week for 16 weeks. En face plaque area was analyzed by oil-red O staining. Serum anti-OxLDL antibodies were measured by ELISA assay. Expression of miR-203 and Ets-2 were evaluated using qRT-RCR and western blotting analysis, respectively.

RESULTS

This study revealed that xiaoxianggou treatment dose-dependently reduced the atherosclerotic plaque area and serum autoantibodies against oxLDL, elevated miR-203 expression and reduced Ets-2 expression in endogenous high Ang II ApoE(-/-) mice. In primary arterial ECs, Xiaoxianggou reverses the reduced miR-203 expression and the elevated Ets-2 expression induced by AngII, which was further recovered by miR-203 inhibitor. Additionally, miR-203 regulated the expression of Ets-2 by targeting Ets-2-3' UTR. Moreover, miR-203 inhibitor reversed the reduction of atherosclerotic lesion area induced by Xiaoxianggou.

CONCLUSIONS

These findings present that xiaoxianggou plays an anti-atherosclerotic role in endogenous high Ang II ApoE(-/-) mice model, which is partly due to its antioxidant actions against atherosclerosis and the inhibition of miR-203 on the expression of Ets-2 in endothelial cells.

Regulation of Vascular Smooth Muscle Cell Dysfunction Under Diabetic Conditions by miR-504

OBJECTIVE

Diabetes mellitus accelerates proatherogenic and proinflammatory phenotype of vascular smooth muscle cell (VSMC) associated with vascular complications. Evidence shows that microRNAs (miRNAs) play key roles in VSMC functions, but their role under diabetic conditions is unclear. We profiled miRNAs in VSMC from diabetic mice and examined their role in VSMC dysfunction.

APPROACH AND RESULTS

High throughput small RNA-sequencing identified 135 differentially expressed miRNAs in VSMC from type 2 diabetic db/db mice (db/dbVSMC) versus nondiabetic db/+ mice. Several of these miRNAs were known to regulate VSMC functions. We further focused on miR-504, because it was highly upregulated in db/dbVSMC, and its function in VSMC is unknown. miR-504 and its host gene Fgf13 were significantly increased in db/dbVSMC and in aortas from db/db mice. Bioinformatics analysis predicted that miR-504 targets including signaling adaptor Grb10 and transcription factor Egr2 could regulate growth factor signaling. We experimentally validated Grb10 and Egr2 as novel targets of miR-504. Overexpression of miR-504 in VSMC inhibited contractile genes and enhanced extracellular signal-regulated kinase 1/2 activation, proliferation, and migration. These effects were blocked by miR-504 inhibitors. Grb10 knockdown mimicked miR-504 functions and increased inflammatory genes. Egr2 knockdown-inhibited anti-inflammatory Socs1 and increased proinflammatory genes. Furthermore, high glucose and palmitic acid upregulated miR-504 and inflammatory genes, but downregulated Grb10.

CONCLUSIONS

Diabetes mellitus misregulates several miRNAs including miR-504 that can promote VSMC dysfunction. Because changes in many of these miRNAs are sustained in diabetic VSMC even after in vitro culture, they may be involved in metabolic memory of vascular complications. Targeting such mechanisms could offer novel therapeutic strategies for diabetic complications.

Estrogen receptor β actions in the female cardiovascular system: A systematic review of animal and human studies

Five medical databases were searched for studies that assessed the role of ERβ in the female cardiovascular system and the influence of age and menopause on ERβ functioning. Of 9472 references, 88 studies met our inclusion criteria (71 animal model experimental studies, 15 human model experimental studies and 2 population based studies). ERβ signaling was shown to possess vasodilator and antiangiogenic properties by regulating the activity of nitric oxide, altering membrane ionic permeability in vascular smooth muscle cells, inhibiting vascular smooth muscle cell migration and proliferation and by regulating adrenergic control of the arteries. Also, a possible protective effect of ERβ signaling against left ventricular hypertrophy and ischemia/reperfusion injury via genomic and non-genomic pathways was suggested in 27 studies. Moreover, 5 studies reported that the vascular effects of ERβ may be vessel specific and may differ by age and menopause status. ERβ seems to possess multiple functions in the female cardiovascular system. Further studies are needed to evaluate whether isoform-selective ERβ-ligands might contribute to cardiovascular disease prevention.

Atherosclerosis and Vascular Biologic Responses to Estrogens: Histologic, Immunohistochemical, Biochemical, and Molecular Methods

Atherogenesis is a multifactorial pathologic process influenced by genetics and environmental factors such as diet, exercise, stress, and other exposures. Estrogen receptors (ER) are expressed in cells of the arterial wall, suggesting that estrogen receptor ligands (estradiol, natural and pharmacologic ligands) may directly affect arterial biology and atherogenesis. Ligand bound estrogen receptor alpha and beta (ERα, ERβ) can influence physiology through direct binding to estrogen response elements in the DNA, through interactions with other transcription factors such as NF-κB, or through rapid effects not dependent on gene expression changes but instead through non-nuclear membrane sites involving ERα, ERβ, or G-coupled protein ER (GPER1). Elucidation of potential direct effects of estrogens on the artery wall requires careful evaluation of arterial biologic responses to estrogens. We have developed a comprehensive approach to understand the mechanisms of estrogen action which employs histologic measures of the size and other characteristics of atherosclerotic lesions, immunohistochemical assessments of cellular composition, evaluation of chemical, molecular, and genomic changes in the arterial environment, and determination of the relationships between arterial estrogen receptor expression and atherogenesis. This approach can provide important insights into the mechanisms of action of estrogen and other mediators of atherogenesis.

miRNAs regulated by estrogens, tamoxifen, and endocrine disruptors and their downstream gene targets

MicroRNAs (miRNAs) are short (22 nucleotides), single-stranded, non-coding RNAs that form complimentary base-pairs with the 3' untranslated region of target mRNAs within the RNA-induced silencing complex (RISC) and block translation and/or stimulate mRNA transcript degradation. The non-coding miRBase (release 21, June 2014) reports that human genome contains ∼ 2588 mature miRNAs which regulate ∼ 60% of human protein-coding mRNAs. Dysregulation of miRNA expression has been implicated in estrogen-related diseases including breast cancer and endometrial cancer. The mechanism for estrogen regulation of miRNA expression and the role of estrogen-regulated miRNAs in normal homeostasis, reproduction, lactation, and in cancer is an area of great research and clinical interest. Estrogens regulate miRNA transcription through estrogen receptors α and β in a tissue-specific and cell-dependent manner. This review focuses primarily on the regulation of miRNA expression by ligand-activated ERs and their bona fide gene targets and includes miRNA regulation by tamoxifen and endocrine disrupting chemicals (EDCs) in breast cancer and cell lines.

miR-599 Inhibits Vascular Smooth Muscle Cells Proliferation and Migration by Targeting TGFB2

Aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) play a crucial role in the pathogenesis of cardiovascular diseases including coronary heart disease, restenosis and atherosclerosis. MicroRNAs are a class of small, non-coding and endogenous RNAs that play critical roles in VSMCs function. In this study, we showed that PDGF-bb, as a stimulant, promoted VSMCs proliferation and suppressed the expression of miR-599. Moreover, overexpression of miR-599 inhibited VSMCs proliferation and also suppressed the PCNA and ki-67 expression. In addition, we demonstrated that ectopic expression of miR-599 repressed the VSMCs migration. We also showed that miR-599 inhibited type I collagen, type V collagen and proteoglycan expression. Furthermore, we identified TGFb2 as a direct target gene of miR-599 in VSMCs. Overexpression of TGFb2 reversed miR-599-induced inhibition of VSMCs proliferation and type I collagen, type V collagen and proteoglycan expression. In conclusion, our findings suggest miR-599 plays a crucial role in controlling VSMCs proliferation and matrix gene expression by regulating TGFb2 expression.

IQGAP1 modulates the proliferation and migration of vascular smooth muscle cells in response to estrogen

Vascular smooth muscle cell (VSMC) proliferation and migration has been proven to be a critical event in the development of varicosity. Variations in estrogen levels, a pathological event related to age and pregnancy, play a role in the pathogenesis of varicosity. Previous studies have reported a different response of VSMCs following estrogen stimulation. However, the exact mechanisms involved have not yet been elucidated. In the present study, we examined the responses of lesion and normal VSMCs treated with 10(-8) M 17β-estradiol (E2) for 24 h. A differential effect of exposure to E2 was observed in these cells. IQ-domain GTPase-activating protein 1 (IQGAP1), a scaffold protein, was overexpressed in the lesion VSMCs and was shown to modulate VSMC proliferation and migration in response to E2. Furthermore, the increased expression of IQGAP1 was found to be intimately associated with a high activity of estrogen receptor α (ERα), which has been implicated in the regulation of VSMC physiological function. Additionally, we found that two critical kinases, Akt and extracellular signal-regulated kinase (ERK), mediated the activation of ERα and VSMC proliferation. According to our results, we thus concluded that high levels of IQGAP1 in VSMCs regulate the physiological reaction of the cells in response to estrogen exposure, and that kinases are involved in the process by mediating ERα activation. In view of the essential role of IQGAP1 in the physiological function of VSMCs, targeting this molecule may prove to be a promising strategy for the treatment of varicosity.

MicroRNA-23a participates in estrogen deficiency induced gap junction remodeling of rats by targeting GJA1

Increased incidence of arrhythmias in women after menopause has been widely documented, which is considered to be related to estrogen (E2) deficiency induced cardiac electrophysiological abnormalities. However, its molecular mechanism remains incompletely clear. In the present study, we found cardiac conduction blockage in post-menopausal rats. Thereafter, the results showed that cardiac gap junctions were impaired and Connexin43 (Cx43) expression was reduced in the myocardium of post-menopausal rats. The phenomenon was also observed in ovariectomized (OVX) rats, which was attenuated by E2 supplement. Further study displayed that microRNA-23a (miR-23a) level was significantly increased in both post-menopausal and OVX rats, which was reversed by daily E2 treatment after OVX. Importantly, forced overexpression of miR-23a led to gap junction impairment and Cx43 downregulation in cultured cardiomyocytes, which was rescued by suppressing miR-23a by transfection of miR-23a specific inhibitory oligonucleotide (AMO-23a). GJA1 was identified as the target gene of miR-23a by luciferase assay and miRNA-masking antisense ODN (miR-Mask) assay. We also found that E2 supplement could reverse cardiac conduction blockage, Cx43 downregulation, gap junction remodeling and miR-23a upregulation in post-menopausal rats. These findings provide the evidence that miR-23a mediated repression of Cx43 participates in estrogen deficiency induced damages of cardiac gap junction, and highlights a new insight into molecular mechanism of post-menopause related arrhythmia at the microRNA level.

Leptin influences estrogen metabolism and accelerates prostate cell proliferation

AIM

The present study was designed to investigate the effect of leptin on estrogen metabolism in prostatic cells.

MAIN METHODS

Malignant (PC-3) and benign (BPH-1) human prostate cells were treated with 17-β-hydroxyestradiol (1 μM) alone or in combination with leptin (0.4, 4, 40 ng/ml) for 72 h. Cell proliferation assay, immunocytochemical staining of estrogen receptor (ER), liquid chromatography-tandem mass spectrometry method (LC-MS) and semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) were used.

KEY FINDINGS

Cell proliferation assay demonstrated that leptin caused significant growth potentiation in both cells. Immunocytochemical staining showed that leptin significantly increased the expression of ER-α and decreased that of ER-β in PC-3 cells. LC-MS method revealed that leptin increased the concentration 4-hydroxyestrone and/or decreased that of 2-methoxyestradiol, 4-methoxyestradiol and 2-methoxyestrone. Interestingly, RT-PCR showed that leptin significantly up-regulated the expression of aromatase and cytochrome P450 1B1 (CYP1B1) enzymes; however down-regulated the expression of catechol-o-methyltransferase (COMT) enzyme.

SIGNIFICANCE

These data indicate that leptin-induced proliferative effect in prostate cells might be partly attributed to estrogen metabolism. Thus, leptin might be a novel target for therapeutic intervention in prostatic disorders.

Oestrogen signalling in white adipose progenitor cells inhibits differentiation into brown adipose and smooth muscle cells

Oestrogen, often via oestrogen receptor alpha (ERα) signalling, regulates metabolic physiology, highlighted by post-menopausal temperature dysregulation (hot flashes), glucose intolerance, increased appetite and reduced metabolic rate. Here we show that ERα signalling has a role in adipose lineage specification in mice. ERα regulates adipose progenitor identity and potency, promoting white adipogenic lineage commitment. White adipose progenitors lacking ERα reprogramme and enter into smooth muscle and brown adipogenic fates. Mechanistic studies highlight a TGFβ programme involved in progenitor reprogramming downstream of ERα signalling. The observed reprogramming has profound metabolic outcomes; both female and male adipose-lineage ERα-mutant mice are lean, have improved glucose sensitivity and are resistant to weight gain on a high-fat diet. Further, they are hypermetabolic, hyperphagic and hyperthermic, all consistent with a brown phenotype. Together, these findings indicate that ERα cell autonomously regulates adipose lineage commitment, brown fat and smooth muscle cell formation, and systemic metabolism, in a manner relevant to prevalent metabolic diseases.

The many faces of estrogen signaling

Estrogens have long been known as important regulators of the female reproductive functions; however, our understanding of the role estrogens play in the human body has changed significantly over the past years. It is now commonly accepted that estrogens and androgens have important functions in both female and male physiology and pathology. This is in part due to the local synthesis and action of estrogens that broadens the role of estrogen signaling beyond that of the endocrine system. Furthermore, there are several different mechanisms through which the three estrogen receptors (ERs), ERα, ERβ and G protein-coupled estrogen receptor 1 (GPER1) are able to regulate target gene transcription. ERα and ERβ are mostly associated with the direct and indirect genomic signaling pathways that result in target gene expression. Membrane-bound GPER1 is on the other hand responsible for the rapid non-genomic actions of estrogens that activate various protein-kinase cascades. Estrogen signaling is also tightly connected with another important regulatory entity, i.e. epigenetic mechanisms. Posttranslational histone modifications, microRNAs (miRNAs) and DNA methylation have been shown to influence gene expression of ERs as well as being regulated by estrogen signaling. Moreover, several coregulators of estrogen signaling also exhibit chromatin-modifying activities further underlining the importance of epigenetic mechanisms in estrogen signaling. This review wishes to highlight the newer aspects of estrogen signaling that exceed its classical endocrine regulatory role, especially emphasizing its tight intertwinement with epigenetic mechanisms.

Interplay between steroid signalling and microRNAs: implications for hormone-dependent cancers

Hormones are key drivers of cancer development. To date, interest has largely been focussed on the classical model of hormonal gene regulation, but there is increasing evidence for a role of hormone signalling pathways in post-translational regulation of gene expression. In particular, a complex and dynamic network of bi-directional interactions with microRNAs (miRs) at all stages of biogenesis and during target gene repression is emerging. miRs, which act mainly by negatively regulating gene expression through association with 3'-UTRs of mRNA species, are increasingly understood to be important in development, normal physiology and pathogenesis. Given recent demonstrations of altered miR profiles in a diverse range of cancers, their ability to function as oncogenes or tumour suppressors, and hormonal regulation of miRs, understanding mechanisms by which miRs are generated and regulated is vitally important. miRs are transcribed by RNA polymerase II and then processed in the nucleus by the Drosha-containing Microprocessor complex and in the cytoplasm by Dicer, before mature miRs are incorporated into the RNA-induced silencing complex. It is increasingly evident that multiple cellular signalling pathways converge upon the miR biogenesis cascade, adding further layers of regulatory complexity to modulate miR maturation. This review summarises recent advances in identification of novel components and regulators of the Microprocessor and Dicer complexes, with particular emphasis on the role of hormone signalling pathways in regulating their activity. Understanding hormone regulation of miR production and how this is perturbed in cancer are critical for the development of miR-based therapeutics and biomarkers.

Estrogen regulation of protein expression and signaling pathways in the heart

Sex differences in cardiovascular disease and cardiac physiology have been reported in humans as well as in animal models. Premenopausal women have reduced cardiovascular disease compared to men, but the incidence of cardiovascular disease in women increases following menopause. Sex differences in cardiomyocytes likely contribute to the differences in male-female physiology and response to disease. Sex differences in the heart have been noted in electrophysiology, contractility, signaling, metabolism, and cardioprotection. These differences appear to be due, at least in part, to differences in gene and protein expression as well as in posttranslational protein modifications. This review will focus primarily on estrogen-mediated male-female differences in protein expression and signaling pathways in the heart and cardiac cells. It should be emphasized that these basic differences are not intrinsically beneficial or detrimental per se; the difference can be good or bad depending on the context and circumstances.

Estrogen regulates the tumour suppressor MiRNA-30c and its target gene, MTA-1, in endometrial cancer

MicroRNA-30c (miR-30c) has been reported to be a tumour suppressor in endometrial cancer (EC). We demonstrate that miR-30c is down-regulated in EC tissue and is highly expressed in estrogen receptor (ER)-negative HEC-1-B cells. MiR-30c directly inhibits MTA-1 expression and functions as a tumour suppressor via the miR-30c-MTA-1 signalling pathway. Furthermore, miR-30c is decreased upon E2 treatment in both ER-positive Ishikawa and ER-negative HEC-1-B cells. Taken together, our results suggest that miR-30c is an important deregulated miRNA in EC and might serve as a potential biomarker and novel therapeutic target for EC.

Oral Bisphenol A (BPA) given to rats at moderate doses is associated with erectile dysfunction, cavernosal lipofibrosis and alterations of global gene transcription

Bisphenol A (BPA), a suspected reproductive biohazard and endocrine disruptor, released from plastics is associated with ED in occupationally exposed workers. However, in rats, despite the induction of hypogonadism, apoptosis of the penile corporal smooth muscle (SM), fat infiltration into the cavernosal tissue and changes in global gene expression with the intraperitoneal administration of high dose BPA, ED was not observed. We investigated whether BPA administered orally rather than intraperitoneally to rats for longer periods and lower doses will lead to ED. Main outcome measures are ED, histological, and biochemical markers in rat penile tissues. In all, 2.5-month-old rats were given drinking water daily without and with BPA at 1 and 0.1 mg kg(-1) per day. Two months later, erectile function was determined by cavernosometry and electrical field stimulation (EFS) and serum levels of testosterone (T), estradiol (E2) and BPA were measured. Penile tissue sections were assayed by Masson (SM/collagen), Oil Red O (fat), terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) (apoptosis), immunohistochemistry for Oct4 (stem cells), and α-SM actin/calponin (SM and myofibroblasts), applying quantitative image analysis. Other markers were assayed by western blotting. DNA microarrays/microRNA (miR) assays defined transcription profiles. Orally administered BPA did not affect body weight, but (1) decreased serum T and E2; (2) reduced the EFS response and increased the drop rate; (3) increased within the corporal tissue the presence of fat, myofibroblasts and apoptosis; (4) lowered the contents of SM and stem cells, but not nerve terminals; and (5) caused alterations in the transcriptional profiles for both mRNA and miRs within the penile shaft. Long-term exposure of rats to oral BPA caused a moderate corporal veno-occlusive dysfunction (CVOD), possibly due to alterations within the corporal tissue that pose gene transcriptional changes related to inflammation, fibrosis and epithelial/mesenchymal transition (EMT).

Ovarian hormones and vascular disease

PURPOSE OF REVIEW

Observational studies have shown benefit of hormone therapy, particularly estrogen, in women who begin treatment in the perimenopausal/early postmenopausal period, whereas randomized controlled trials of such therapy in older postmenopausal women have reported harm. These apparently paradoxical findings have led to the 'timing hypothesis' which proposes that estrogen signaling is altered in older women, converting vasoprotective to vasotoxic effects. We reviewed recent literature on age-dependent effects of hormones (particularly estrogen) on the vasculature of women and the fundamental cellular/molecular mechanisms responsible for those effects.

RECENT FINDINGS

Observational studies have shown that early menopause is associated with adverse cardiovascular disease outcomes and that starting hormone therapy in the perimenopausal period reduces these outcomes. Mechanistic studies have shown that estrogen modulates injury-induced inflammation, growth factor expression, and oxidative stress in arteries and vascular smooth muscle cells isolated from young women but that these vasoprotective mechanisms are lost in women who are aged and/or deprived of estrogen for prolonged periods of time.

SUMMARY

The vasoprotective effects of estrogen are age-dependent and disappear with aging and/or estrogen deprivation. Future studies designed to preserve the vasoprotective effects of estrogen in older women are needed and may lead to innovative approaches to improving women's cardiovascular health.

Deletion of yes-associated protein (YAP) specifically in cardiac and vascular smooth muscle cells reveals a crucial role for YAP in mouse cardiovascular development

RATIONALE

Our previous study has shown that yes-associated protein (YAP) plays a crucial role in the phenotypic modulation of vascular smooth muscle cells (SMCs) in response to arterial injury. However, the role of YAP in vascular SMC development is unknown.

OBJECTIVE

The goal of this study was to investigate the functional role of YAP in cardiovascular development in mice and determine the mechanisms underlying YAP's actions.

METHODS AND RESULTS

YAP was deleted in cardiomyocytes and vascular SMCs by crossing YAP flox mice with SM22α-Cre transgenic mice. Cardiac/SMC-specific deletion of YAP directed by SM22α-Cre resulted in perinatal lethality in mice because of profound cardiac defects including hypoplastic myocardium, membranous ventricular septal defect, and double outlet right ventricle. The cardiac/SMC-specific YAP knockout mice also displayed severe vascular abnormalities including hypoplastic arterial wall, short/absent brachiocephalic artery, and retroesophageal right subclavian artery. Deletion of YAP in mouse vascular SMCs induced expression of a subset of cell cycle arrest genes including G-protein-coupled receptor 132 (Gpr132). Silencing Gpr132 promoted SMC proliferation, whereas overexpression of Gpr132 attenuated SMC growth by arresting cell cycle in G0/G1 phase, suggesting that ablation of YAP-induced impairment of SMC proliferation was mediated, at least in part, by induction of Gpr132 expression. Mechanistically, YAP recruited the epigenetic repressor histone deacetylase-4 to suppress Gpr132 gene expression via a muscle CAT element in the Gpr132 gene.

CONCLUSIONS

YAP plays a critical role in cardiac/SMC proliferation during cardiovascular development by epigenetically regulating expression of a set of cell cycle suppressors.

MicroRNAs in cardiovascular health: from order to disorder

In the last decade, microRNAs (miRNAs) have revolutionized how we understand metabolism and disease. These small, 20- to 22-nucleotide RNA molecules fine-tune gene expression and can often coordinate multiple genes in a single pathway. Given the multifactorial nature of cardiovascular disease, it is perhaps not surprising that miRNAs have been shown to orchestrate many aspects of disease development, from modulating metabolic risk factors over a lifetime (eg, cholesterol and hormones) to controlling the response to an acute cardiovascular event (eg, inflammation and hypoxia). In this review, we discuss how miRNAs exert control over metabolic pathways that maintain vascular health and, when these pathways go awry, how miRNAs can be targeted for therapeutic modulation.

miR-222 contributes to sex-dimorphic cardiac eNOS expression via ets-1

It is well recognized that there is sex-dimorphic expression of mRNA and protein in the heart; however, the underlying mechanism is poorly understood. Endothelial nitric oxide synthase (eNOS) is an important regulator of cardiac function, and the expression levels of eNOS differ between male and female hearts. The aim of this study was to examine whether expression of specific microRNA (miRNA, miR) in males and females contributes to changes in the expression of eNOS. miRNA was extracted from the myocardium of male and female C57BL/6 mice and subjected to an Affymetrix miRNA array. Decreased expression of miR-222 was discovered in females and confirmed by qRT-PCR from whole heart or isolated cardiomyocytes. The transcription factor V-ets erythroblastosis virus E26 oncogene homolog-1 (ets-1) was identified as a potential target of miR-222 using TargetScan, and fivefold increased ets-1 protein expression in females was confirmed by Western blot. Targeting of ets-1 by miR-222 was determined in HEK293 cells overexpressing luciferase under regulation of either the ets-1 3'-UTR, a null 3'-UTR control, or a scrambled ets-1 3'-UTR and treated with a small molecule miR-222 mimic or inhibitor. Additionally qRT-PCR confirmed that mRNA levels of the ets-1 transcriptional target, eNOS, were 25% higher in females. Compared with untreated myocyte controls, 50% inhibition of eNOS expression was achieved by treatment with a miR-222 mimic, compared with a 25% increase due to miR-222 inhibitor. Our findings indicate that sex-dependent miR-222 regulation alters the expression of the cardiac regulatory protein eNOS.