Resveratrol inhibits high glucose induced collagen upregulation in cardiac fibroblasts through regulating TGF-β1–Smad3 signaling pathway

Anti-proliferative impact of resveratrol on gingival fibroblasts from juvenile hyaline fibromatosis

AIM

Resveratrol is a natural polyphenolic compound with biological activities such as anti-inflammation and antioxidation. Its anti-fibrotic effect has been experimentally demonstrated in the pancreas and liver. This study aims to determine the anti-proliferative effect of resveratrol on fibroblasts obtained from hyperplastic gingival tissues from a patient diagnosed with Juvenile Hyaline Fibromatosis (JHF).

MATERIALS AND METHODS

Primary gingival fibroblast cell lines were obtained from gingival growth tissues by the gingivectomy of a patient with JHF. Gingival fibroblasts were treated with or without 3 different doses of resveratrol (50, 100, 200 µM). Cytotoxicity and cell proliferation were evaluated after 24, 48, and 72 h. Collagen, TGF, and CTGF were analyzed by ELISA in the 48-hour supernatants.

RESULTS

All three doses of resveratrol suppressed the proliferation of JHF gingival fibroblasts at 24 and 48 h without showing any cytotoxic effect compared to the control group (p < 0.0001). At 72 h, 100 and 200 µM resveratrol showed significantly less proliferation (p < 0.0001), less collagen, CTGF, and TGF- β (p < 0.001) than the control group.

CONCLUSION

Resveratrol had a profound anti-proliferative effect on gingival fibroblasts obtained from gingival enlargements with JHF, suggesting that it can be used as a therapeutic to prevent excessive cell growth by suppressing collagen, CTGF, and TGF- β synthesis in the pathogenesis of hyperplasia.

Resveratrol plays an anti-fibrotic and anti-autophagy role by stimulating miR-192-5p expression in urethral fibrosis

BACKGROUND

Resveratrol (RSV) exerts anti-fibrotic effects on various fibrotic diseases. Whereas the biological role of RSV on urethral fibrosis remains to be elucidated. This study aimed to determine the mechanisms by which RSV affects urethral fibrosis and autophagy.

METHODS

Sprague‒Dawley rats and primary fibroblasts were treated with transforming growth factor-β1 (TGFβ1) to generate in vivo and in vitro fibrosis models. Then, those were treated with RSV, and autophagy and fibrosis-related indicators were tested.

RESULTS

Firstly, we found that RSV reversed the upregulation of indicators related to TGFβ1-induced fibrosis (TGFβ1, α-smooth muscle actin, collagen type I, and collagen type III), autophagy (TFEB and LC3), and TGFβR1/Smad4 pathway, as well as the downregulation of p62 and miR-192-5p expression both in vivo and in vitro. Overexpression of miR-192-5p suppressed the upregulation of fibrosis-related markers expression, as well as TFEB and LC3 expression, induced by TGFβ1, while the expression trend of p62 was the opposite. Inhibiting miR-192-5p reversed the effects of RSV on the model group cells. It was also shown that RSV combined with sh-Smad4 inhibited autophagy more effectively than RSV alone.

CONCLUSION

These results suggest that RSV inhibits urinary fibrosis and autophagy via the miR-192-5p/TGFβR1/Smad4 pathway. RAV may be a potential drug for alleviating urethral fibrosis.

Huoxin Pill inhibits isoproterenol-induced transdifferentiation and collagen synthesis in cardiac fibroblasts through the TGF-β/Smads pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The abnormal proliferation and differentiation of cardiac fibroblasts (CFs) are universally regarded as the key process for the progressive development of cardiac fibrosis following various cardiovascular diseases. Huoxin Pill (Concentrated pill, HXP) is a Chinese herbal formula for treating coronary heart disease. However, the cellular and molecular mechanisms of HXP in the treatment of myocardial fibrosis are still unclear.

AIM OF THE STUDY

To investigate the effects of HXP on CFs transdifferentiation and collagen synthesis under isoproterenol (ISO) conditions, as well as the potential mechanism of action.

MATERIALS AND METHODS

In vivo, we established a rat model of cardiac fibrosis induced by ISO, and administered with low or high dose of HXP (10 mg/kg/day or 30 mg/kg/day). The level of α-SMA was detected by immunohistochemistry examination, and combined with RNA-sequencing analysis to determine the protective effect of HXP on myocardial fibrosis rats. In vitro, by culturing primary rat CFs, we examined the effects of HXP on the proliferation and transdifferentiation of CFs using CCK8, scratch wound healing and immunofluorescence assays. Western blot was used to determine protein expression.

RESULTS

The findings revealed that HXP protects against ISO-induced cardiac fibrosis and CFs transdifferentiation in rats. RNA-sequencing and pathway analyses demonstrated 238 or 295 differentially expressed genes (DEGs) and multiple enriched signal pathways, including transforming growth factor-beta (TGF-β) receptor signaling activates Smads, downregulation of TGF-β receptor signaling, signaling by TGF-β receptor complex, and collagen formation under treatment with low or high-dose of HXP. Moreover, HXP also markedly inhibited ISO-induced primary rat CFs proliferation, transdifferentiation, collagen synthesis and the upregulation of TGF-β1 and phosphorylated Smad2/3 protein expression.

CONCLUSION

HXP suppresses ISO-induced CFs transdifferentiation and collagen synthesis, and it may exert these effects in part by inhibiting the activation of the TGF-β/Smads pathway. This may be a new therapeutic tool for cardiac fibrosis.

Resveratrol could attenuate prostatic inflammation in rats with Oestradiol-induced chronic prostatitis

To evaluate the effect of resveratrol in rats with chronic prostatitis, 24 rats were randomly divided into the negative control, vehicle-treated and resveratrol groups. The rats in the vehicle-treated group and the resveratrol group were injected subcutaneously with 17-β-oestradiol (0.25 mg/kg) daily for 6 weeks while the rats in the control group were injected with equivalent normal saline. From the 45th day, the rats in the resveratrol group were given resveratrol (10 mg/kg) by gavage per day while the rest rats were given normal saline. After 55 days, all the rats were sacrificed and the prostatic tissue was removed. Morphological changes were examined by light microscope after H&E staining. The expressions of IL-6, IL-8 and TNF-α were determined through ELISA and immunohistochemical staining. As a result, significant inflammatory cell infiltration and fibroblastic hyperplasia were observed in prostatic stroma in the vehicle-treated group compared with the negative control group, as well as the high expression of IL-6, IL-8 and TNF-α. After resveratrol treatment, inflammatory cell infiltration and fibroblastic hyperplasia were shown prominently reduced. Meanwhile, the expression of IL-6, IL-8 and TNF-α was significantly suppressed. For conclusion, resveratrol could attenuate the prostatic inflammation and downregulate the expression of IL-6, IL-8 and TNF-α in rat with oestradiol-induced chronic prostatitis.

Resveratrol Modulates Transforming Growth Factor-Beta (TGF-β) Signaling Pathway for Disease Therapy: A New Insight into Its Pharmacological Activities

Resveratrol (Res) is a well-known natural product that can exhibit important pharmacological activities such as antioxidant, anti-diabetes, anti-tumor, and anti-inflammatory. An evaluation of its therapeutic effects demonstrates that this naturally occurring bioactive compound can target different molecular pathways to exert its pharmacological actions. Transforming growth factor-beta (TGF-β) is an important molecular pathway that is capable of regulating different cellular mechanisms such as proliferation, migration, and angiogenesis. TGF-β has been reported to be involved in the development of disorders such as diabetes, cancer, inflammatory disorders, fibrosis, cardiovascular disorders, etc. In the present review, the relationship between Res and TGF-β has been investigated. It was noticed that Res can inhibit TGF-β to suppress the proliferation and migration of cancer cells. In addition, Res can improve fibrosis by reducing inflammation via promoting TGF-β down-regulation. Res has been reported to be also beneficial in the amelioration of diabetic complications via targeting the TGF-β signaling pathway. These topics are discussed in detail in this review to shed light on the protective effects of Res mediated via the modulation of TGF-β signaling.

The Diabetic Cardiac Fibroblast: Mechanisms Underlying Phenotype and Function

Diabetic cardiomyopathy involves remodeling of the heart in response to diabetes that includes microvascular damage, cardiomyocyte hypertrophy, and cardiac fibrosis. Cardiac fibrosis is a major contributor to diastolic dysfunction that can ultimately result in heart failure with preserved ejection fraction. Cardiac fibroblasts are the final effector cell in the process of cardiac fibrosis. This review article aims to describe the cardiac fibroblast phenotype in response to high-glucose conditions that mimic the diabetic state, as well as to explain the pathways underlying this phenotype. As such, this review focuses on studies conducted on isolated cardiac fibroblasts. We also describe molecules that appear to oppose the pro-fibrotic actions of high glucose on cardiac fibroblasts. This represents a major gap in knowledge in the field that needs to be addressed.

Optimization and evaluation of novel tetrahydropyrido[4,3-d]pyrimidine derivatives as ATX inhibitors for cardiac and hepatic fibrosis

Aiming to develop potent autotaxin (ATX) inhibitors for fibrosis diseases, a novel series of tetrahydropyrido[4,3-d]pyrimidine derivatives was designed and synthesized based on our previous study. The enzymatic assay combined with anti-proliferative activities against cardiac fibroblasts (CFs) and hepatic stellate cell (HSC) in vitro were applied for preliminary evaluation of anti-fibrosis potency of target compounds, resulting in two outstanding ATX inhibitors 8b and 10g with the IC₅₀ values in a nanomolar range (24.6 and 15.3 nM). Differently, 8b was the most prominent compound against CFs with inhibition ratio of 81.5%, while 10g exhibited the maximum inhibition ratio of 83.7% against t-HSC/Cl-6 cells. In the further pharmacological evaluations in vivo, collagen deposition assay demonstrated the conspicuous capacity of 8b to suppress TGF-β-mediated cardiac fibrosis. Simultaneously, H&E and Masson stains assays of mice liver validated 10g as an excellent anti-hepatofibrosis candidate, which reduced CCl₄-induced hepatic fibrosis level prominently. Besides, the molecular binding models identified the essential interactions between 8b and ATX which was coincided with the SARs.

Doxycycline Improves Fibrosis-Induced Abnormalities in Atrial Conduction and Vulnerability to Atrial Fibrillation in Chronic Intermittent Hypoxia Rats

Background

The structural remodeling of atrial architecture, especially increased amounts of fibrosis, is a critical substrate to atrial fibrillation (AF). Doxycycline (Doxy) has recently been shown to exert protective effects against fibrogenic response. This study investigated whether doxycycline (Doxy) can sufficiently ameliorate the fibrosis-induced changes of atrial conduction and AF vulnerability in a chronic intermittent hypoxia (CIH) rat model.

Material/Methods

Sixty rats were randomized into 3 groups: Control, CIH, and CIH with Doxy treatment (DOXY) group. CIH rats were exposed to CIH (6 h/d) and Doxy-treated rats were treated with Doxy during processing CIH. After 6 weeks, echocardiographic and hemodynamic parameters were measured. Isolated atrial epicardial activation mapping and heart electrophysiology were performed. The extent of atrial interstitial fibrosis were estimated by Masson’s trichrome staining. The expression levels of TGF-β1 and downstream factors were determined by real-Time PCR, immunohistochemistry, and Western blot analysis.

Results

Compared to Control rats, the CIH rats showed significant atrial interstitial fibrosis, longer inter-atrial conduction time, and elevated conduction inhomogeneity and AF inducibility, and the expression of TGF-β1, TGF-βRI, TGF-βRII, P-Smad2/3, α-SMA, CTGF, and Collagen I were significantly increased, whereas the velocity of atrial conduction and the expression of miR-30c were dramatically decreased. All of these changes were significantly improved by Doxy treatment.

Conclusions

The findings suggested that Doxy can profoundly mitigate atrial fibrosis, conduction inhomogeneity as well as high AF inducibility secondary to fibrosis in a CIH rat model through suppressing the TGF-β1 signaling pathway.

Attenuation of diabetic cardiomyopathy by relying on kirenol to suppress inflammation in a diabetic rat model

Diabetic cardiomyopathy is characterized by diabetes‐induced myocardial abnormalities, accompanied by inflammatory response and alterations in inflammation‐related signalling pathways. Kirenol, isolated from Herba Siegesbeckiae, has potent anti‐inflammatory properties. In this study, we aimed to investigate the cardioprotective effect of kirenol against DCM and underlying the potential mechanisms in a type 2 diabetes mellitus model. Kirenol treatment significantly decreased high glucose‐induced cardiofibroblasts proliferation and increased the cardiomyocytes viability, prevented the loss of mitochondrial membrane potential and further attenuated cardiomyocytes apoptosis, accompanied by a reduction in apoptosis‐related protein expression. Kirenol gavage could affect the expression of pro‐inflammatory cytokines in a dose‐dependent manner but not lower lipid profiles, and only decrease fasting plasma glucose, fasting plasma insulin and mean HbA1c levels in high‐dose kirenol‐treated group at some time‐points. Left ventricular dysfunction, hypertrophy, fibrosis and cell apoptosis, as structural and functional abnormalities, were ameliorated by kirenol administration. Moreover, in diabetic hearts, oral kirenol significantly attenuated activation of mitogen‐activated protein kinase subfamily and nuclear translocation of NF‐κB and Smad2/3 and decreased phosphorylation of IκBα and both fibrosis‐related and apoptosis‐related proteins. In an Electrophoretic mobility shift assay, the binding activities of NF‐κB, Smad3/4, SP1 and AP‐1 in the nucleus of diabetic myocardium were significantly down‐regulated by kirenol treatment. Additionally, high dose significantly enhanced myocardial Akt phosphorylation without intraperitoneal injection of insulin. Kirenol may have potent cardioprotective effects on treating for the established diabetic cardiomyopathy, which involves the inhibition of inflammation and fibrosis‐related signalling pathways and is independent of lowering hyperglycaemia, hyperinsulinemia and lipid profiles.

MiR-32-5p influences high glucose-induced cardiac fibroblast proliferation and phenotypic alteration by inhibiting DUSP1

Background

The current study aimed to investigate the effects of miR-32-5p on cardiac fibroblasts (CFs) that were induced with high levels of glucose; we also aimed to identify the potential mechanisms involved in the regulation of DUSP1 expression.

Methods

Human CFs were transfected with a miR-32-5p inhibitor or mimic and were treated with a normal concentration or a high concentration of glucose. Flow cytometry analysis was performed to identify cardiac fibroblasts by examining vimentin, fibronectin (FN) and α-actin expression in human CFs. qRT-PCR and western blot assays were performed to confirm the expression of miR-32-5p, DUSP1 and cardiac fibrosis relevant proteins. The proliferation of CFs was assessed by using MTT assay. An immunocytofluorescent staining assay was performed to determine the protein level of α-SMA and to investigate the degree of phenotypic changes in human CFs. The specific relationship between miR-32-5p and DUSP1 was investigated by a dual luciferase reporter assay. Cell apoptosis rates were measured with flow cytometry and the annexin V-FITC and propidine iodide (PI) staining method.

Results

A luciferase reporter assay indicated that miR-32-5p could directly target DUSP1. High glucose levels resulted in the overexpression of miR-32-5p, which downregulated DUSP1 expression. Both the upregulation of miR-32-5p and the downregulation of DUSP1 promoted cell apoptosis, proliferation and phenotypic changes in human CFs.

Conclusions

All findings in this study provide further evidence for the positive effects of miR-32-5p on cell proliferation and the phenotypic changes in CFs by inhibiting DUSP1 expression, and reveal that miR-32-5p could serve as prognostic diagnostic target for cardiac fibrosis.

Electronic supplementary material

The online version of this article (10.1186/s12867-019-0135-x) contains supplementary material, which is available to authorized users.

Salvianolic Acid B-Alleviated Angiotensin II Induces Cardiac Fibrosis by Suppressing NF-κB Pathway In Vitro

BACKGROUND Salvianolic acid B (SalB) is the representative component of phenolic acids derived from the roots and rhizomes of Salvia miltiorrhiza Bge (Labiatae), which has been used widely in Asian countries for clinical therapy of various cardiovascular dysfunction-related diseases. However, cardiac protection effects and the underlying mechanism for clinical application are still poorly understood. Here, we investigated the potential anti-myocardial fibrosis effect and mechanism of SalB on Angiotensin II (Ang II)-induced cardiac fibrosis in vitro. MATERIAL AND METHODS The proliferation and migration capacity of cardiac fibroblasts (CFBs) were measured by MTT assay and scratch analysis, respectively. The colorimetric assay determined the hydroxyproline content in medium. Western blotting detected the protein expressions of nuclear transcription factor-kappa B (NF-κB) pathway-associated proteins, fibronectin (FN), collagen type I (Coll I), α-smooth muscle actin (α-SMA), and connective tissue growth factor (CTGF). The expression of α-SMA protein was observed by immunofluorescence staining. qRT-PCR detected the mRNA expression of NF-κB. RESULTS SalB attenuated Ang II-induced the proliferation and the migration ability of CFBs. Ang II-induced the extracellular matrix protein Coll I, FN, and α-SMA, the pro-fibrotic cytokine CTGF protein expression was inhibited, and the nuclear translocation of NF-κB p65 subunit was reduced by SalB. Western blotting and qRT-PCR confirmed that SalB blocked the activation of NF-κB induced by Ang II. PDTC (the NF-κB inhibitor) also inhibited proliferation of CFBs and reduced α-SMA and Coll I expression induced by Ang II. CONCLUSIONS SalB can alleviate Ang II-induced cardiac fibrosis via suppressing the NF-κB pathway in vitro.

Discovery and optimization of tetrahydropyrido[4,3-d]pyrimidine derivatives as novel ATX and EGFR dual inhibitors

In order to discovery autotaxin (ATX) and EGFR dual inhibitors with potential therapeutic effect on IPF-LC, a series of novel tetrahydropyrido[4,3-d]pyrimidine derivatives possessing semicarbazones moiety were designed and synthesized. The preliminary investigation at the cellular level indicated six compounds (7h, 8a, 8c, 8d, 9a and 9d) displayed preferable anti-tumor activities against A549, H1975, MKN-45 and SGC cancer cells. Further enzymatic assay against EGFR kinase identified 8a and 9a as promising hits with IC₅₀ values of 18.0 nM and 24.2 nM. Meanwhile, anti-inflammatory assessment against cardiac fibroblasts (CFs) cell and RAW264.7 macrophages led to the discovery of candidate 9a, which exhibited considerable potency both on inhibition rate of 77% towards CFs and on reducing NO production to 1.05 μM at 10 μg/mL. Simultaneously, 9a indicated preferable potency towards ATX with IC₅₀ value of 29.1 nM. Significantly, a RT-PCR study revealed the function of 9a to down-regulate the mRNA expression of TGF-β and TNF-α in a dose-dependent manner. The molecular docking analysis together with the pharmacological studies validated 9a as a potential ATX and EGFR dual inhibitor for IPF-LC treatments.

Diabetes as risk factor for pancreatic cancer: Hyperglycemia promotes epithelial-mesenchymal-transition and stem cell properties in pancreatic ductal epithelial cells

Type 2 diabetes mellitus (T2DM) is associated with hyperglycemia and a risk to develop pancreatic ductal adenocarcinoma (PDAC), one of the most fatal malignancies. Cancer stem cells (CSC) are essential for initiation and maintenance of tumors, and acquisition of CSC-features is linked to epithelial-mesenchymal-transition (EMT). The present study investigated whether hyperglycemia promotes EMT and CSC-features in premalignant and malignant pancreatic ductal epithelial cells (PDEC). Under normoglycemia (5 mM d-glucose), Panc1 PDAC cells but not premalignant H6c7-kras cells exhibited a mesenchymal phenotype along with pronounced colony formation. While hyperglycemia (25 mM d-glucose) did not impact the mesenchymal phenotype of Panc1 cells, CSC-properties were aggravated exemplified by increased Nanog expression and Nanog-dependent formation of holo- and meroclones. In H6c7-kras cells, high glucose increased secretion of Transforming-Growth-Factor-beta1 (TGF-β1) as well as TGF-β1 signaling, and in a TGF-β1-dependent manner reduced E-cadherin expression, increased Nestin expression and number of meroclones. Finally, reduced E-cadherin expression was detected in pancreatic ducts of hyperglycemic but not normoglycemic mice. These data suggest that hyperglycemia promotes the acquisition of mesenchymal and CSC-properties in PDEC by activating TGF-β signaling and might explain how T2DM facilitates pancreatic tumorigenesis.

Oligomeric proanthocyanidins protect myocardium by mitigating left ventricular remodeling in isoproterenol-induced postmyocardial infarction

Extracellular matrix (ECM) remodeling is a major pathophysiological process during post-myocardial infarction (MI). The activation, differentiation, and proliferation of cardiac fibroblasts to myofibroblasts regulate the expression of ECM proteins. The signaling by bone morphogenetic protein (BMP-4), an extracellular ligand of the TGF-β family, has recently been identified as an essential pathway in regulating cardiovascular dysfunctions including myocardial fibrosis. Oligomeric proanthocyanidins (OPC) are well known for their cardioprotective activity. The primary aim of the study was to investigate BMP-4-mediated ECM turnover in cardiac fibrosis during isoproterenol-induced post-MI and its downregulation by OPC. Myocardial injury was evaluated by assaying serum markers LDH and CK. Oxidative stress and the enzymatic and nonenzymatic antioxidant levels were assessed to support the cardioprotective nature of OPC. The total collagen level was analyzed by measuring hydroxyproline levels. The ISO-induced group showed a significant decrease in the levels of antioxidants due to severe oxidative stress and increased expression of BMP-4 which reflects the increased expression of MMP 2 and 9 with a concomitant increase and deposition of fibrillary collagens type I and III responsible for the fibrotic scar formation as evidenced in the histological analysis.BMP-4 activation, thus, is strongly associated with cardiac fibrosis which was downregulated upon OPC supplementation. This study provides an evidence supporting the antifibrotic effect of OPC via regulation of BMP-4-mediated ECM turnover and also substantiates the remarkable antioxidant efficacy of OPC against isoproterenol induced severe oxidative stress and subsequent post-MI cardiac fibrosis.

Extracellular Vesicles as Protagonists of Diabetic Cardiovascular Pathology

Extracellular vesicles (EVs) represent an emerging mechanism of cell–cell communication in the cardiovascular system. Recent data suggest that EVs are produced and taken up by multiple cardiovascular cell types, influencing target cells through signaling or transfer of cargo (including proteins, lipids, messenger RNA, and non-coding RNA). The concentration and contents of circulating EVs are altered in several diseases and represent explicit signatures of cellular activation, making them of particular interest as circulating biomarkers. EVs also actively contribute to the progression of various cardiovascular diseases, including diabetes-related vascular disease. Understanding the relationships between circulating EVs, diabetes, and cardiovascular disease is of importance as diabetic patients are at elevated risk for developing several debilitating cardiovascular pathologies, including diabetic cardiomyopathy (DCM), a disease that remains an enigma at the molecular level. Enhancing and exploiting our understanding of EV biology could facilitate the development of effective non-invasive diagnostics, prognostics, and therapeutics. This review will focus on EV biology in diabetic cardiovascular diseases, including atherosclerosis and DCM. We will review EV biogenesis and functional properties, as well as provide insight into their emerging role in cell–cell communication. Finally, we will address the utility of EVs as clinical biomarkers and outline their impact as a biomedical tool in the development of therapeutics.

Resveratrol improves prostate fibrosis during progression of urinary dysfunction in chronic prostatitis

AIM

We investigated whether prostate fibrosis was associated with urinary dysfunction in chronic prostatitis (CP) and whether resveratrol improved urinary dysfunction and the underlying molecular mechanism.

METHODS

Rat model of CP was established via subcutaneous injections of DPT vaccine and subsequently treated with resveratrol. Bladder pressure and volume tests investigated the effect of resveratrol on urinary dysfunction in CP rats. Western blotting and immunohistochemical staining examined the expression level of C-kit/SCF and TGF-β/Wnt/β-catenin.

RESULTS

Compared to the control group, the maximum capacity of the bladder, residual urine volume and maximum voiding pressure, the activity of C-kit/SCF and TGF-β/Wnt/β-catenin pathways were increased significantly in the CP group. Resveratrol treatment significantly improved these factors.

CONCLUSION

CP induced significantly prostate fibrosis, which exhibits a close relationship with urinary dysfunction. Resveratrol improved fibrosis, which may be associated with the suppression of C-kit/SCF and TGF-β/Wnt/β-catenin pathway.

MicroRNA-9 inhibits high glucose-induced proliferation, differentiation and collagen accumulation of cardiac fibroblasts by down-regulation of TGFBR2

To investigate the effects of miR-9 on high glucose (HG)-induced cardiac fibrosis in human cardiac fibroblasts (HCFs), and to establish the mechanism underlying these effects. HCFs were transfected with miR-9 inhibitor or mimic, and then treated with normal or HG. Cell viability and proliferation were detected by using the Cell Counting Kit-8 (CCK-8) assay and Brdu-ELISA assay. Cell differentiation and collagen accumulation of HCFs were detected by qRT-PCR and Western blot assays respectively. The mRNA and protein expressions of transforming growth factor-β receptor type II (TGFBR2) were determined by qRT-PCR and Western blotting. Up-regulation of miR-9 dramatically improved HG-induced increases in cell proliferation, differentiation and collagen accumulation of HCFs. Moreover, bioinformatics analysis predicted that the TGFBR2 was a potential target gene of miR-9 Luciferase reporter assay demonstrated that miR-9 could directly target TGFBR2. Inhibition of TGFBR2 had the similar effect as miR-9 overexpression. Down-regulation of TGFBR2 in HCFs transfected with miR-9 inhibitor partially reversed the protective effect of miR-9 overexpression on HG-induced cardiac fibrosis in HCFs. Up-regulation of miR-9 ameliorates HG-induced proliferation, differentiation and collagen accumulation of HCFs by down-regulation of TGFBR2. These results provide further evidence for protective effect of miR-9 overexpression on HG-induced cardiac fibrosis.

Treatment of cardiovascular pathology with epigenetically active agents: Focus on natural and synthetic inhibitors of DNA methylation and histone deacetylation

Cardiovascular disease (CVD) retains a leadership as a major cause of human death worldwide. Although a substantial progress was attained in the development of cardioprotective and vasculoprotective drugs, a search for new efficient therapeutic strategies and promising targets is under way. Modulation of epigenetic CVD mechanisms through administration epigenetically active agents is one of such new approaches. Epigenetic mechanisms involve heritable changes in gene expression that are not linked to the alteration of DNA sequence. Pathogenesis of CVDs is associated with global genome-wide changes in DNA methylation and histone modifications. Epigenetically active compounds that influence activity of epigenetic modulators such as DNA methyltransferases (DNMTs), histone acetyltransferases, histone deacetylases (HDACs), etc. may correct these pathogenic changes in the epigenome and therefore be used for CVD therapy. To date, many epigenetically active natural substances (such as polyphenols and flavonoids) and synthetic compounds such as DNMT inhibitors or HDAC inhibitors are known. Both native and chemical DNMT and HDAC inhibitors possess a wide range of cytoprotective activities such as anti-inflammatory, antioxidant, anti-apoptotic, anti-anfibrotic, and anti-hypertrophic properties, which are beneficial of treatment of a variety of CVDs. However, so far, only synthetic DNMT inhibitors enter clinical trials while synthetic HDAC inhibitors are still under evaluation in preclinical studies. In this review, we consider epigenetic mechanisms such as DNA methylation and histone modifications in cardiovascular pathology and the epigenetics-based therapeutic approaches focused on the implementation of DNMT and HDAC inhibitors.

MicroRNA-29a suppresses cardiac fibroblasts proliferation via targeting VEGF-A/MAPK signal pathway

Cardiac fibroblasts proliferation is the most important pathophysiological character of cardiac fibrosis while the underlying mechanisms are still incompletely known. MicroRNAs (miRNAs) regulate gene expression by binding to specific sites. Studies have been indicated that miRNA-29a play a key role in cardiac fibrosis. VEGF-A carries out its functions through MAPK signaling pathway in cardiac fibrosis. Existing proofs predict that the VEGF-A is one of the potential targets of miRNA-29a. We therefore probe the role of miRNA-29a and its latent target VEGF-A during cardiac fibrosis. In our study, miRNA-29a was down-regulated while VEGF-A was up-regulated in cardiac fibrosis tissues. The rat cardiac fibroblasts that were transfected with miRNA-29a inhibitor exhibited low-expression of miRNA-29a, enhanced VEGF-A protein and mRNA expression. Nevertheless, the cardiac fibroblasts transfected with miRNA-29a mimics obtained the opposite expression result. Furthermore, over-expression of miRNA-29a suppresses cardiac fibroblasts proliferation. In conclusion, these results suggested that miRNA-29a suppresses cardiac fibrosis and fibroblasts proliferation via targeting VEGF-A/MAPK signal pathway implicating that miRNA-29a might play a role in the treatment of cardiac fibrosis.

Resveratrol ameliorates myocardial fibrosis by inhibiting ROS/ERK/TGF-β/periostin pathway in STZ-induced diabetic mice

BACKGROUND

Myocardial fibrosis is an essential hallmark of diabetic cardiomyopathy (DCM) contributing to cardiac dysfunctions. Resveratrol, an antioxidant, exerts its anti-fibrotic effect via inhibition of oxidative stress, while the underlying molecular mechanism remains largely elusive. Periostin, a fibrogenesis matricellular protein, has been shown to be associated with oxidative stress. In the present study, we investigated the role of periostin in anti-fibrotic effect of resveratrol in streptozocin (STZ)-induced diabetic heart and the underlying mechanisms.

METHODS

Diabetic mice were induced by STZ injection. After treatment with resveratrol (5 or 25 mg/kg/day i.g) or Saline containing 0.5% carboxymethyl cellulose (CMC) for 2 months, the hearts were detected for oxidative stress and cardiac fibrosis using western blot, Masson's trichrome staining and Dihydroethidium (DHE) staining. In in vitro experiments, proliferation and differentiation of fibroblasts under different conditions were investigated through western blot, 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay and immunofluorescence staining.

RESULTS

Administration of resveratrol significantly mitigated oxidative level, interstitial fibrosis and expressions of related proteins in STZ-induced diabetic hearts. In in vitro experiments, resveratrol exhibited anti-proliferative effect on primary mouse cardiac fibroblasts via inhibiting reactive oxygen species (ROS)/extracellular regulated kinase (ERK) pathway and ameliorated myofibroblast differentiation via suppressing ROS/ERK/ transforming growth factor β (TGF-β)/periostin pathway.

CONCLUSION

Increased ROS production, activation of ERK/TGF-β/periostin pathway and myocardial fibrosis are important events in DCM. Alleviated ROS genesis by resveratrol prevents myocardial fibrosis by regulating periostin related signaling pathway. Thus, inhibition of ROS/periostin may represent a novel approach for resveratrol to reverse fibrosis in DCM.

Protective effect of resveratrol against caspase 3 activation in primary mouse fibroblasts

Aim

To study the effect of resveratrol on survival and caspase 3 activation in non-transformed cells after serum deprivation.

Methods

Apoptosis was induced by serum deprivation in primary mouse embryonic fibroblasts. Caspase 3 activation and lactate dehydrogenase release were assayed as cell viability measure by using their fluorogenic substrates. The involvement of PI3K, ERK, JNK, p38, and SIRT1 signaling pathways was also examined.

Results

Serum deprivation of primary fibroblasts induced significant activation of caspase 3 within 3 hours and reduced cell viability after 24 hours. Resveratrol dose-dependently prevented caspase activation and improved cell viability with 50% inhibitory concentration (IC₅₀) = 66.3 ± 13.81 µM. It also reduced the already up-regulated caspase 3 activity when it was added to the cell culture medium after 3 hour serum deprivation, suggesting its rescue effect. Among the major signaling pathways, p38 kinase was critical for the protective effect of resveratrol which was abolished completely in the presence of p38 inhibitor.

Conclusion

Resveratrol showed protective effect against cell death in a rather high dose. Involvement of p38 kinase in this effect suggests the role of mild stress in its cytoprotective action. Furthermore due to its rescue effect, resveratrol may be used not only for prevention, but also treatment of age-related degenerative diseases, but in the higher dose than consumed in conventional diet.

Resveratrol ameliorates high glucose-induced oxidative stress injury in human umbilical vein endothelial cells by activating AMPK

AIMS

To investigate the effects of resveratrol on high glucose (HG)-induced vascular injury, and to establish the mechanism(s) underlying these effects.

MAIN METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with glucose, and then incubated with resveratrol in the presence or absence of Compound C, an AMP-activated protein kinase (AMPK) inhibitor. Cell viability was determined using the Cell Counting Kit-8 (CCK-8) method. Reactive oxygen species, malondialdehyde, and superoxide dismutase were detected by flow cytometry, thiobarbituric acid reaction, and the nitroblue tetrazolium method, respectively. Protein levels of total and phosphorylated AMPKα and acetyl-CoA carboxylase were detected by immunoblotting.

KEY FINDINGS

Resveratrol significantly ameliorated HG-induced decreases in cell viability and superoxide dismutase levels and increases in reactive oxygen species and MDA levels. Moreover, resveratrol significantly reversed HG-induced dephosphorylation of AMPKα and acetyl-CoA carboxylase. However, treatment with Compound C curtailed the beneficial effects of resveratrol on HG-treated HUVECs.

SIGNIFICANCE

Resveratrol ameliorates HG-induced injury in HUVECs by activation of AMPKα, leading to increased cellular reductive reactions and decreased oxidative stress. These results provide further evidence for resveratrol-mediated activation of AMPKα.