Inhibition of cardiac fibroblast proliferation and myofibroblast differentiation by resveratrol

Chronic activation of human cardiac fibroblasts in vitro attenuates the reversibility of the myofibroblast phenotype

Activation of cardiac fibroblasts and differentiation to myofibroblasts underlies development of pathological cardiac fibrosis, leading to arrhythmias and heart failure. Myofibroblasts are characterised by increased α-smooth muscle actin (α-SMA) fibre expression, secretion of collagens and changes in proliferation. Transforming growth factor-beta (TGF-β) and increased mechanical stress can initiate myofibroblast activation. Reversibility of the myofibroblast phenotype has been observed in murine cells but has not been explored in human cardiac fibroblasts. In this study, chronically activated adult primary human ventricular cardiac fibroblasts and human induced pluripotent stem cell derived cFbs (hiPSC-cFbs) were used to investigate the potential for reversal of the myofibroblast phenotype using either subculture on soft substrates or TGF-β receptor inhibition. Culture on softer plates (25 or 2 kPa Young's modulus) did not alter proliferation or reduce expression of α-SMA and collagen 1. Similarly, culture of myofibroblasts in the presence of TGF-β inhibitor did not reverse myofibroblasts back to a quiescent phenotype. Chronically activated hiPSC-cFbs also showed attenuated response to TGF-β receptor inhibition and inability to reverse to quiescent fibroblast phenotype. Our data demonstrate substantial loss of TGF-β signalling plasticity as well as a loss of feedback from the surrounding mechanical environment in chronically activated human myofibroblasts.

Pro-inflammatory cytokine secretion induced by amyloid transthyretin in human cardiac fibroblasts

Extracellular aggregates of wild-type human transthyretin are associated with heart diseases such as wild-type transthyretin (TTR)-derived amyloidosis (ATTR-wt). Due to their strategic location, cardiac fibroblasts act as sentinel cells that sense injury and activate the inflammasome. No studies of the effects of TTR amyloid aggregation on the secretion of inflammatory factors by primary human cardiac fibroblasts (hCFs) have been reported yet. The intracellular internalization of TTR aggregates, which correspond to the early stage of ATTR-wt, were determined using immunofluorescence and Western blotting of cell lysates. A further objective of this study was to analyze the secretion of inflammatory factors by hCFs after analysis of TTR amyloid aggregation using X-MAP® Luminex Assay techniques. We show that TTR aggregates are internalized in hCFs and induce the secretion of both Brain Natriuretic Peptide (BNP) and N-terminal pro B-type Natriuretic Peptide(NT-proBNP). Also, pro-inflammatory mediators such as interleukin-6 (IL-6) and IL-8 are secreted without significant changes in the levels of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). In conclusion, these findings suggest that IL-6 and IL-8 play important roles in the development of ATTR-wt, and indicate that IL-6 in particular could be a potentially important therapeutic target in patients with ATTR-wt.

Role of resveratrol in inhibiting pathological cardiac remodeling

Cardiovascular disease is a group of diseases with high mortality in clinic, including hypertension, coronary heart disease, cardiomyopathy, heart valve disease, heart failure, to name a few. In the development of cardiovascular diseases, pathological cardiac remodeling is the most common cardiac pathological change, which often becomes a domino to accelerate the deterioration of the disease. Therefore, inhibiting pathological cardiac remodeling may delay the occurrence and development of cardiovascular diseases and provide patients with greater long-term benefits. Resveratrol is a non-flavonoid polyphenol compound. It mainly exists in grapes, berries, peanuts and red wine, and has cardiovascular protective effects, such as anti-oxidation, inhibiting inflammatory reaction, antithrombotic, dilating blood vessels, inhibiting apoptosis and delaying atherosclerosis. At present, the research of resveratrol has made rich progress. This review aims to summarize the possible mechanism of resveratrol against pathological cardiac remodeling, in order to provide some help for the in-depth exploration of the mechanism of inhibiting pathological cardiac remodeling and the development and research of drug targets.

Resveratrol against Cardiac Fibrosis: Research Progress in Experimental Animal Models

Cardiac fibrosis is a heterogeneous disease, which is characterized by abundant proliferation of interstitial collagen, disordered arrangement, collagen network reconstruction, increased cardiac stiffness, and decreased systolic and diastolic functions, consequently developing into cardiac insufficiency. With several factors participating in and regulating the occurrence and development of cardiac fibrosis, a complex molecular mechanism underlies the disease. Moreover, cardiac fibrosis is closely related to hypertension, myocardial infarction, viral myocarditis, atherosclerosis, and diabetes, which can lead to serious complications such as heart failure, arrhythmia, and sudden cardiac death, thus seriously threatening human life and health. Resveratrol, with the chemical name 3,5,4'-trihydroxy-trans-stilbene, is a polyphenol abundantly present in grapes and red wine. It is known to prevent the occurrence and development of cardiovascular diseases. In addition, it may resist cardiac fibrosis through a variety of growth factors, cytokines, and several cell signaling pathways, thus exerting a protective effect on the heart.

Hsp90 Inhibitor Attenuates the Development of Pathophysiological Cardiac Fibrosis in Mouse Hypertrophy via Suppression of the Calcineurin-NFAT and c-Raf-Erk Pathways

ABSTRACT

In the previous study, we showed that an Hsp90 inhibitor, 17-(allylamino)-17-demethoxygeldanamycin (17-AAG), attenuates hypertrophic remodeling of cardiomyocytes during the development of heart failure. In this present study, we investigated the effects of 17-AAG on cardiac fibrosis during the development of heart failure. We used pressure-loaded cardiac hypertrophic mice prepared by constriction of the transverse aorta (TAC), which induces significant cardiac fibrosis without scar tissue. From the sixth week after the TAC operation, vehicle or 17-AAG was administered intraperitoneally twice a week. Eight weeks after the operation, the vehicle-treated animals showed chronic heart failure. On the other hand, cardiac deterioration of the 17-AAG-treated animals was attenuated. In 17-AAG-treated animals, when the degree of fibrosis was observed by histological staining, their volume of fibrosis was found to be reduced. The content of calcineurin, an Hsp90 client protein, and the level of dephosphorylated NFATc2, a transcription factor in the cardiac fibroblasts, in the TAC mice was reduced by treatment with 17-AAG. Furthermore, c-Raf and Erk signaling, indicators for cell proliferation and collagen synthesis, was also attenuated. In in vitro experiments, the proliferation and collagen synthesis of the cultured cardiac fibroblasts were attenuated by the presence of 17-AAG. When cardiac fibroblasts were incubated with angiotensin II, calcineurin-NFATc2 and c-Raf-Erk signaling in the cells were activated. These activations were attenuated by 17-AAG. Our findings suggest that suppression of the calcineurin-NFAT and c-Raf-Erk pathways may partially contribute to the attenuation of myocardial fibrosis caused by treatment with 17-AAG. Therefore, our data imply that the Hsp90 inhibitor may have potential for novel therapeutic strategy for the treatment of heart failure.

Dimethyl fumarate preserves left ventricular infarct integrity following myocardial infarction via modulation of cardiac macrophage and fibroblast oxidative metabolism

Myocardial infarction (MI) is one of the leading causes of mortality and cardiovascular disease worldwide. MI is characterized by a substantial inflammatory response in the infarcted left ventricle (LV), followed by transition of quiescent fibroblasts to active myofibroblasts, which deposit collagen to form the reparative scar. Metabolic shifting between glycolysis and mitochondrial oxidative phosphorylation (OXPHOS) is an important mechanism by which these cell types transition towards reparative phenotypes. Thus, we hypothesized that dimethyl fumarate (DMF), a clinically approved anti-inflammatory agent with metabolic actions, would improve post-MI remodeling via modulation of macrophage and fibroblast metabolism. Adult male C57BL/6J mice were treated with DMF (10 mg/kg) for 3-7 days after MI. DMF attenuated LV infarct and non-infarct wall thinning at 3 and 7 days post-MI, and decreased LV dilation and pulmonary congestion at day 7. DMF improved LV infarct collagen deposition, myofibroblast activation, and angiogenesis at day 7. DMF also decreased pro-inflammatory cytokine expression (Tnf) 3 days after MI, and decreased inflammatory markers in macrophages isolated from the infarcted heart (Hif1a, Il1b). In fibroblasts extracted from the infarcted heart at day 3, RNA-Seq analysis demonstrated that DMF promoted an anti-inflammatory/pro-reparative phenotype. By Seahorse analysis, DMF did not affect glycolysis in either macrophages or fibroblasts at day 3, but enhanced macrophage OXPHOS while impairing fibroblast OXPHOS. Our results indicate that DMF differentially affects macrophage and fibroblast metabolism, and promotes anti-inflammatory/pro-reparative actions. In conclusion, targeting cellular metabolism in the infarcted heart may be a promising therapeutic strategy.

Bellidifolin Ameliorates Isoprenaline-Induced Myocardial Fibrosis by Regulating TGF-β1/Smads and p38 Signaling and Preventing NR4A1 Cytoplasmic Localization

Myocardial fibrosis is closely related to high morbidity and mortality. In Inner Mongolia, Gentianella amarella subsp. acuta (Michx.) J.M.Gillett (G. acuta) is a kind of tea used to prevent cardiovascular diseases. Bellidifolin (BEL) is an active xanthone molecule from G. acuta that protects against myocardial damage. However, the effects and mechanisms of BEL on myocardial fibrosis have not been reported. In vivo, BEL dampened isoprenaline (ISO)-induced cardiac structure disturbance and collagen deposition. In vitro, BEL inhibited transforming growth factor (TGF)-β1-induced cardiac fibroblast (CF) proliferation. In vivo and in vitro, BEL decreased the expression of α-smooth muscle actin (α-SMA), collagen Ⅰ and Ⅲ, and inhibited TGF-β1/Smads signaling. Additionally, BEL impeded p38 activation and NR4A1 (an endogenous inhibitor for pro-fibrogenic activities of TGF-β1) phosphorylation and inactivation in vitro. In CFs, inhibition of p38 by SB203580 inhibited the phosphorylation of NR4A1 and did not limit Smad3 phosphorylation, and blocking TGF-β signaling by LY2157299 and SB203580 could decrease the expression of α-SMA, collagen I and III. Overall, both cell and animal studies provide a potential role for BEL against myocardial fibrosis by inhibiting the proliferation and phenotypic transformation of CFs. These inhibitory effects might be related to regulating TGF-β1/Smads pathway and p38 signaling and preventing NR4A1 cytoplasmic localization.

Berry-Derived Polyphenols in Cardiovascular Pathologies: Mechanisms of Disease and the Role of Diet and Sex

Cardiovascular disease (CVD) prevalence, pathogenesis, and manifestation is differentially influenced by biological sex. Berry polyphenols target several signaling pathways pertinent to CVD development, including inflammation, oxidative stress, and cardiac and vascular remodeling, and there are innate differences in these pathways that also vary by sex. There is limited research systematically investigating sex differences in berry polyphenol effects on these pathways, but there are fundamental findings at this time that suggest a sex-specific effect. This review will detail mechanisms within these pathological pathways, how they differ by sex, and how they may be individually targeted by berry polyphenols in a sex-specific manner. Because of the substantial polyphenolic profile of berries, berry consumption represents a promising interventional tool in the treatment and prevention of CVD in both sexes, but the mechanisms in which they function within each sex may vary.

Characterization of primary adult mouse cardiac fibroblast cultures

The role of cardiac fibroblasts (CFs) in disease states has been a focus of cardiovascular research over the past decade. Here, we briefly describe methods for isolation and characterization of CFs from adult mouse ventricles. Primary cultures were stained using antibodies for several marker proteins such as α-smooth muscle actin (αSMA), vimentin, and discoidin domain receptor 2 (DDR2) to confirm the identity of CFs or cardiac myofibroblasts (CMFs). Most cells in primary cultures consisted of CFs, with very low frequencies of endothelial cells, cardiomyocytes, and smooth muscle cells. We compared marker expression between cultures that were not passaged (P0) or passaged for few times (P1-3). When compared with P1-3 cultures, P0 cultures consistently displayed a lower percentage of cells positive for αSMA and DDR2, whereas vimentin expression was significantly higher in P0 cultures compared with P1-3 cultures. P0 cells were also smaller in area than P1-3 cells. Further, P1-3 mouse CFs were found to express both β1 and β2 adrenergic receptors (ARs) and β1ARs were more readily detected on the cell surface compared with β2ARs. In summary, mouse CF cultures underwent phenotype conversion into CMFs after passaging, consistent with what is seen with CF cultures from other species.

Influence of Angiotensin-converting Enzyme Insertion/Deletion Gene Polymorphism in Progression of Chagas Heart Disease

INTRODUCTION

Chagas disease (CD) is a neglected disease caused by the parasite Trypanosoma cruzi. One-third of infected patients will develop the cardiac form, which may progress to heart failure (HF). However, the factors that determine disease progression remain unclear. Increased angiotensin II activity is a key player in the pathophysiology of HF. A functional polymorphism of the angiotensin-converting enzyme (ACE) gene is associated with plasma enzyme activity. In CD, ACE inhibitors have beneficial effects supporting the use of this treatment in chagasic cardiomyopathy.

METHODS

We evaluated the association of ACE I/D polymorphism with HF, performing a case-control study encompassing 343 patients with positive serology for CD staged as non-cardiomyopathy (stage A; 100), mild (stage B1; 144), and severe (stage C; 99) forms of Chagas heart disease. For ACE I/D genotyping by PCR, groups were compared using unconditional logistic regression analysis and adjusted for nongenetic covariates: age, sex, and trypanocidal treatment.

RESULTS

A marginal, but not significant (p=0.06) higher prevalence of ACE I/D polymorphism was observed in patients in stage C compared with patients in stage A. Patients in stage C (CD with HF), were compared with patients in stages A and B1 combined into one group (CD without HF); DD genotype/D carriers were prevalent in the HF patients (OR = 2; CI = 1.013.96; p = 0.04).

CONCLUSIONS

Our results of this cohort study, comprising a population from the Northeast region of Brazil, suggest that ACE I/D polymorphism is more prevalent in the cardiac form of Chagas disease with HF.

Coordinated regulation of cell survival and cell cycle pathways by DDR2-dependent SRF transcription factor in cardiac fibroblasts

Relative resistance to apoptosis and the ability to proliferate and produce a collagen-rich scar determine the critical role of cardiac fibroblasts in wound healing and tissue remodeling following myocardial injury. Identification of cardiac fibroblast-specific factors and mechanisms underlying these aspects of cardiac fibroblast function is therefore of considerable scientific and clinical interest. In the present study, gene knockdown and overexpression approaches and promoter binding assays showed that discoidin domain receptor 2 (DDR2), a mesenchymal cell-specific collagen receptor tyrosine kinase localized predominantly in fibroblasts in the heart, acts via ERK1/2 MAPK-activated serum response factor (SRF) transcription factor to enhance the expression of antiapoptotic cIAP2 in cardiac fibroblasts, conferring resistance against oxidative injury. Furthermore, DDR2 was found to act via ERK1/2 MAPK-activated SRF to transcriptionally upregulate Skp2 that in turn facilitated post-translational degradation of p27, the cyclin-dependent kinase inhibitor that causes cell cycle arrest, to promote G₁-S transition, as evidenced by Rb phosphorylation, increased proliferating cell nuclear antigen (PCNA) levels, and flow cytometry. DDR2-dependent ERK1/2 MAPK activation also suppressed forkhead box O 3a (FoxO3a)-mediated transcriptional induction of p27. Inhibition of the binding of collagen type I to DDR2 using WRG-28 indicated the obligate role of collagen type I in the activation of DDR2 and its regulatory role in cell survival and cell cycle protein expression. Notably, DDR2 levels positively correlated with SRF, cIAP2, and PCNA levels in cardiac fibroblasts from spontaneously hypertensive rats. To conclude, DDR2-mediated ERK1/2 MAPK activation facilitates coordinated regulation of cell survival and cell cycle progression in cardiac fibroblasts via SRF.NEW & NOTEWORTHY Relative resistance to apoptosis and the ability to proliferate and produce a collagen-rich scar enable cardiac fibroblasts to play a central role in myocardial response to injury. This study reports novel findings that mitogen-stimulated cardiac fibroblasts exploit a common regulatory mechanism involving collagen receptor (DDR2)-dependent activation of ERK1/2 MAPK and serum response factor to achieve coordinated regulation of apoptosis resistance and cell cycle progression, which could facilitate their survival and function in the injured myocardium.

Cytoprotective effects of (E)-N-(2-(3, 5-dimethoxystyryl) phenyl) furan-2-carboxamide (BK3C231) against 4-nitroquinoline 1-oxide-induced damage in CCD-18Co human colon fibroblast cells

Stilbenes are a group of chemicals characterized with the presence of 1,2-diphenylethylene. Previously, our group has demonstrated that synthesized (E)-N-(2-(3, 5-dimethoxystyryl) phenyl) furan-2-carboxamide (BK3C231) possesses potential chemopreventive activity specifically inducing NAD(P)H:quinone oxidoreductase 1 (NQO1) protein expression and activity. In this study, the cytoprotective effects of BK3C231 on cellular DNA and mitochondria were investigated in normal human colon fibroblast, CCD-18Co cells. The cells were pretreated with BK3C231 prior to exposure to the carcinogen 4-nitroquinoline 1-oxide (4NQO). BK3C231 was able to inhibit 4NQO-induced cytotoxicity. Cells treated with 4NQO alone caused high level of DNA and mitochondrial damages. However, pretreatment with BK3C231 protected against these damages by reducing DNA strand breaks and micronucleus formation as well as decreasing losses of mitochondrial membrane potential (ΔΨm) and cardiolipin. Interestingly, our study has demonstrated that nitrosative stress instead of oxidative stress was involved in 4NQO-induced DNA and mitochondrial damages. Inhibition of 4NQO-induced nitrosative stress by BK3C231 was observed through a decrease in nitric oxide (NO) level and an increase in glutathione (GSH) level. These new findings elucidate the cytoprotective potential of BK3C231 in human colon fibroblast CCD-18Co cell model which warrants further investigation into its chemopreventive role.

Activation of CXCR7 alleviates cardiac insufficiency after myocardial infarction by promoting angiogenesis and reducing apoptosis

Angiogenesis is an important pathway for revascularization of ischemic tissues after acute myocardial infarction (AMI). It is unclear what role CXCR7 plays in angiogenesis in the ischemic area after AMI, although some researchers have shown that the activation of CXCR7 protectsthe heart under those conditions. Here, we hypothesize that the activation of CXCR7 promotes angiogenesis, reduces cell apoptosis and alleviates cardiac deficiency after AMI. C57BL/6 J mice were subjected to AMI and treated with TC14012 (10 mg/kg) for 24 days. HUVECs were cultured in a hypoxic (2% O₂) environment to generate a model of hypoxia. CXCR7 was knocked down in HUVECs by sh-CXCR7 transfection, and CXCR7 was activated by TC14012 (30 μM) treatment. The results showed that CXCR7 was downregulated in infarcted heart tissue and hypoxic HUVECs. The global activation of CXCR7 may alleviate the decrease in cardiac function indexes - (ejection fraction and fraction shortening), and reduce infarct size after AMI.. Moreover, CXCR7 activation has been shown to enhance the level of angiogenesis in ischemic heart tissue. In vitro, hypoxia-induced angiogenic functional loss and apoptosis are aggravated by CXCR7 knockdown in HUVECs. Both angiogenic impairment and cell apoptosis are rescued by CXCR7 activation. In conclusion, the present study indicates that activation of CXCR7 plays an important protective role for ischemic cells in hypoxic endothelial cells and AMI model mice by promoting angiogenesis and reducing apoptosis, which suggests that CXCR7 may be a potential therapeutic target to rescue the ischemic myocardium..

Resveratrol Prevents Right Ventricle Remodeling and Dysfunction in Monocrotaline-Induced Pulmonary Arterial Hypertension with a Limited Improvement in the Lung Vasculature

Pulmonary arterial hypertension (PAH) is a life-threatening disease that is characterized by an increase in pulmonary vascular pressure, leading to ventricular failure and high morbidity and mortality. Resveratrol, a phenolic compound and a sirtuin 1 pathway activator, has known dietary benefits and is used as a treatment for anti-inflammatory and cardiovascular diseases. Its therapeutic effects have been published in the scientific literature; however, its benefits in PAH are yet to be precisely elucidated. Using a murine model of PAH induced by monocrotaline, the macroscopic and microscopic effects of a daily oral dose of resveratrol in rats with PAH were evaluated by determining its impact on the lungs and the right and left ventricular function. While most literature has focused on smooth muscle cell mechanisms and lung pathology, our results highlight the relevance of therapy-mediated improvement of right ventricle and isolated cardiomyocyte physiology in both ventricles. Although significant differences in the pulmonary architecture were not identified either micro- or macroscopically, the effects of resveratrol on right ventricular function and remodeling were observed to be beneficial. The values for the volume, diameter, and contractility of the right ventricular cardiomyocytes returned to those of the control group, suggesting that resveratrol has a protective effect against ventricular dysfunction and pathological remodeling changes in PAH. The effect of resveratrol in the right ventricle delayed the progression of findings associated with right heart failure and had a limited positive effect on the architecture of the lungs. The use of resveratrol could be considered a future potential adjunct therapy, especially when the challenges to making a diagnosis and the current therapy limitations for PAH are taken into consideration.

Biological approaches for hypertrophic scars

Scar formation is usually the pathological consequence of skin trauma. And hypertrophic scars (HSs) frequently occur in people after being injured deeply. HSs are unusually considered as the result of tissue contraction and excessive extracellular matrix component deposition. Myofibroblasts, as the effector cells, mainly differentiated from fibroblasts, play the crucial role in the pathophysiology of HSs. A number of growth factors, inflammatory cytokines involved in the process of HS occurrence. Currently, with in-depth exploration and clinical research of HSs, various creative and effective treatments budded. In here, we summarize the progress in the molecular mechanism of HSs, and review the available biotherapeutic methods for their pathophysiological characteristics. Additionally, we further prospected that the comprehensive therapy may be more suitable for HS treatment.

Resveratrol suppresses the myofibroblastic phenotype and fibrosis formation in kidneys via proliferation-related signalling pathways

BACKGROUND AND PURPOSE

Renal fibrosis acts as the common pathway leading to the development of end-stage renal disease. Previous studies have shown that resveratrol has anti-fibrotic activity, but its potential molecular mechanisms of action are not well understood.

EXPERIMENTAL APPROACH

The anti-fibrotic effects of resveratrol were assayed in a rat model of unilateral ureteral obstruction (UUO) in vivo and in fibroblasts and tubular epithelial cells (TECs) stimulated by TGF-β1 in vitro. Gene and protein expression levels were analysed by PCR, Western blotting, and immunohistochemical staining.

KEY RESULTS

Resveratrol inhibits the myofibroblastic phenotype and fibrosis formation in UUO kidneys by targeting fibroblast-myofibroblast differentiation (FMD) and epithelial-mesenchymal transition (EMT). The anti-fibrotic effects of resveratrol correlated with decreased proliferation of TECs in the interstitium and tubules, resulting in suppressed activity of the proliferation-related signalling pathways, including that of the MAPK, PI3K/Akt, Wnt/β-catenin, and JAK2/STAT3 pathways. Resveratrol treatment suppressed TGF-β1-induced FMD and the expression of the myofibroblastic phenotype in fibroblasts in vitro by antagonizing the activation of proliferation-related signalling. Similarly, TGF-β1-mediated overactivation of the proliferation-related signalling in TECs induced EMT, and the myofibroblastic phenotype was suppressed by resveratrol. The anti-fibrotic and anti-proliferative effects of resveratrol were associated with the inactivation of Smad2/3 signalling and resulted in a partial reversal of FMD and EMT and the inhibition of the myofibroblastic phenotype.

CONCLUSIONS AND IMPLICATIONS

Resveratrol suppresses the myofibroblastic phenotype and fibrosis formation in vivo and in vitro via proliferation-related pathways, making it a potential therapeutic agent for preventing renal fibrosis.

FGF23-Mediated Activation of Local RAAS Promotes Cardiac Hypertrophy and Fibrosis

Patients with chronic kidney disease (CKD) are prone to developing cardiac hypertrophy and fibrosis, which is associated with increased fibroblast growth factor 23 (FGF23) serum levels. Elevated circulating FGF23 was shown to induce left ventricular hypertrophy (LVH) via the calcineurin/NFAT pathway and contributed to cardiac fibrosis by stimulation of profibrotic factors. We hypothesized that FGF23 may also stimulate the local renin–angiotensin–aldosterone system (RAAS) in the heart, thereby further promoting the progression of FGF23-mediated cardiac pathologies. We evaluated LVH and fibrosis in association with cardiac FGF23 and activation of RAAS in heart tissue of 5/6 nephrectomized (5/6Nx) rats compared to sham-operated animals followed by in vitro studies with isolated neonatal rat ventricular myocytes and fibroblast (NRVM, NRCF), respectively. Uremic rats showed enhanced cardiomyocyte size and cardiac fibrosis compared with sham. The cardiac expression of Fgf23 and RAAS genes were increased in 5/6Nx rats and correlated with the degree of cardiac fibrosis. In NRVM and NRCF, FGF23 stimulated the expression of RAAS genes and induced Ngal indicating mineralocorticoid receptor activation. The FGF23-mediated hypertrophic growth of NRVM and induction of NFAT target genes were attenuated by cyclosporine A, losartan and spironolactone. In NRCF, FGF23 induced Tgfb and Ctgf, which were suppressed by losartan and spironolactone, only. Our data suggest that FGF23-mediated activation of local RAAS in the heart promotes cardiac hypertrophy and fibrosis.

Divergent Effects of Resveratrol on Rat Cardiac Fibroblasts and Cardiomyocytes

In this study, we tested the potential cardioprotective effects of the phytoalexin resveratrol (Rsv) on primary adult rat cardiac fibroblasts (CF), myofibroblasts (MF) and cardiomyocytes. Adult rat CF and cardiomyocytes were isolated from male 10-week old Sprague–Dawley rats, cultured for either 24 h (cardiomyocytes) or 48 h (CF) before treatments. To isolate MF, CF were trypsinized after 48 h in culture, seeded in fresh plates and cultured for 24 h prior to treatment. All three cells were then treated for a further 24 h with a range of Rsv doses. In CF and MF, cell proliferation, viability, apoptosis assays were performed with or without Rsv treatment for 24 h. In cardiomyocytes, cell viability and apoptosis assay were performed 24 h after treatment. In separate experiments, CF was pre-incubated with estrogen, tamoxifen and fulvestrant for 30 min prior to Rsv treatment. Rsv treatment decreased proliferation of both fibroblasts and myofibroblasts. Rsv treatment also increased the proportion of dead CF and MF in a dose dependent manner. However, treatment with Rsv did not induce cell death in adult cardiomyocytes. There was an increase in the percentage of cells with condensed nuclei with Rsv treatment in both CF and MF, but not in cardiomyocytes. Treatment with estrogen, tamoxifen and fulvestrant alone or in combination with Rsv did not have any additional effects on CF survival. Our results demonstrate that treatment with Rsv can inhibit cell proliferation and induce cell death in rat CF and MF, while not affecting cardiomyocyte survival. We also demonstrated that the induction of cell death in CF with Rsv treatment was independent of estrogen receptor alpha (ERα) signaling.

Regulation of cardiac fibroblast-mediated maladaptive ventricular remodeling by β-arrestins

Cardiac fibroblasts (CF) play a critical role in post-infarction remodeling which can ultimately lead to pathological fibrosis and heart failure. Recent evidence demonstrates that remote (non-infarct) territory fibrosis is a major mechanism for ventricular dysfunction and arrhythmogenesis. β-arrestins are important signaling molecules involved in β-adrenergic receptor (β-AR) desensitization and can also mediate signaling in a G protein independent fashion. Recent work has provided evidence that β-arrestin signaling in the heart may be beneficial, however, these studies have primarily focused on cardiac myocytes and their role in adult CF biology has not been well studied. In this study, we show that β-arrestins can regulate CF biology and contribute to pathological fibrosis. Adult male rats underwent LAD ligation to induce infarction and were studied by echocardiography. There was a significant decline in LV function at 2–12 weeks post-MI with increased infarct and remote territory fibrosis by histology consistent with maladaptive remodeling. Collagen synthesis was upregulated 2.9-fold in CF isolated at 8 and 12 weeks post-MI and β-arrestin expression was significantly increased. β-adrenergic signaling was uncoupled in the post-MI CF and β-agonist-mediated inhibition of collagen synthesis was lost. Knockdown of β-arrestin1 or 2 in the post-MI CF inhibited transformation to myofibroblasts as well as basal and TGF-β-stimulated collagen synthesis. These data suggest that β-arrestins can regulate CF biology and that targeted inhibition of these signaling molecules may represent a novel approach to prevent post-infarction pathological fibrosis and the transition to HF.

Mechanical regulation of gene expression in cardiac myocytes and fibroblasts

The intact heart undergoes complex and multiscale remodelling processes in response to altered mechanical cues. Remodelling of the myocardium is regulated by a combination of myocyte and non-myocyte responses to mechanosensitive pathways, which can alter gene expression and therefore function in these cells. Cellular mechanotransduction and its downstream effects on gene expression are initially compensatory mechanisms during adaptations to the altered mechanical environment, but under prolonged and abnormal loading conditions, they can become maladaptive, leading to impaired function and cardiac pathologies. In this Review, we summarize mechanoregulated pathways in cardiac myocytes and fibroblasts that lead to altered gene expression and cell remodelling under physiological and pathophysiological conditions. Developments in systems modelling of the networks that regulate gene expression in response to mechanical stimuli should improve integrative understanding of their roles in vivo and help to discover new combinations of drugs and device therapies targeting mechanosignalling in heart disease.

Transient Receptor Potential Canonical 3 and Nuclear Factor of Activated T Cells C3 Signaling Pathway Critically Regulates Myocardial Fibrosis

AIMS

Cardiac fibroblasts (CFs) are emerging as major contributors to myocardial fibrosis (MF), a final common pathway of many etiologies of heart disease. Here, we studied the functional relevance of transient receptor potential canonical 3 (TRPC3) channels and nuclear factor of activated T cells c3 (NFATc3) signaling in rodent and human ventricular CFs, and whether their modulation would limit MF.

RESULTS

A positive feedback loop between TRPC3 and NFATc3 drove a rat ventricular CF fibrotic phenotype. In these cells, polyphenols (extract of grape pomace polyphenol [P.E.]) decreased basal and angiotensin II-mediated Ca²⁺ entries through a direct modulation of TRPC3 channels and subsequently NFATc3 signaling, abrogating myofibroblast differentiation, fibrosis and inflammation, as well as an oxidative stress-associated phenotype. N(ω)-nitro-l-arginine methyl ester (l-NAME) hypertensive rats developed coronary perivascular, sub-epicardial, and interstitial fibrosis with induction of embryonic epicardial progenitor transcription factors in activated CFs. P.E. treatment reduced ventricular CF activation by modulating the TRPC3-NFATc3 pathway, and it ameliorated echocardiographic parameters, cardiac stress markers, and MF in l-NAME hypertensive rats independently of blood pressure regulation. Further, genetic deletion (TRPC3^-/-) and pharmacological channel blockade with N-[4-[3,5-Bis(trifluoromethyl)-1H-pyrazol-1-yl]phenyl]-4-methyl-benzenesulfonamide (Pyr10) blunted ventricular CF activation and MF in l-NAME hypertensive mice. Finally, TRPC3 was present in human ventricular CFs and upregulated in MF, whereas pharmacological modulation of TRPC3-NFATc3 decreased proliferation and collagen secretion. Innovation and Conclusion: We demonstrate that TRPC3-NFATc3 signaling is modulated by P.E. and critically regulates ventricular CF phenotype and MF. These findings strongly argue for P.E., through TRPC3 targeting, as potential and interesting therapeutics for MF management.

Triptolide inhibits migration and proliferation of fibroblasts from ileocolonic anastomosis of patients with Crohn's disease via regulating the miR‑16‑1/HSP70 pathway

Anastomotic fibrosis is highly likely to lead to reoperation in Crohn's disease (CD) patients. Triptolide (TPL) is considered to have anti-inflammatory and antifibrotic effects in a variety of autoimmune diseases, including CD. The present study aimed to investigate the effects of TPL on fibroblasts from strictured ileocolonic anastomosis of patients with CD and its underlying mechanism. Primary fibroblasts were obtained from strictured anastomosis tissue (SAT) samples and matched anastomosis-adjacent normal tissue (NT) samples which were collected from 10 CD patients who underwent reoperation because of anastomotic stricture. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to measure miR-16-1 and heat shock protein 70 (HSP70) levels. Western blotting was conducted to determine expression of HSP70, collagen I (Col-I), collagen III (Col-III) and α-smooth muscle actin (α-SMA) proteins. Agomir-16-1 and antagomir-16-1 were used to up and downregulate the expression of miR-16-1, respectively. Small interfering RNA (siRNA) was employed to inhibit the expression of HSP70. A wound healing assay was performed to measure the migration of fibroblasts. Cell proliferation was evaluated by MTT and 5-bromo-2-deoxyrudidine assays. Cell apoptosis was determined by caspase-3 activity and TUNEL assays. The results demonstrated that the levels of Col-I, Col-III and α-SMA were all significantly upregulated in SAT compared with NT. miR-16-1 levels in the SAT group were significantly compared with the NT group; conversely, the expression levels of HSP70 mRNA and protein in the SAT group were significantly lower compared with the NT group. Next, fibroblasts were treated with TPL to examine its effect on the miR-16-1/HSP70 pathway. The results demonstrated that the elevated expression of miR-16-1 in the SAT group was effectively inhibited by TPL treatment. Compared with the NT group, both the mRNA and protein levels of HSP70 were significantly downregulated in the SAT group cells, while TPL exhibited a strong promoting effect on HSP70 synthesis. Furthermore, upregulation of miR-16-1 reversed the effect of TPL on the miR-16-1/HSP70 pathway in fibroblasts from SAT. Overexpression of miR-16-1 significantly reversed the inhibitory effects of TPL treatment on migration, proliferation and extracellular matrix (ECM)-associated protein expression of fibroblasts from SAT. Finally, downregulation of miR-16-1 caused similar effects to the fibroblasts as the TPL treatment; however, the inhibitory effects on cell biological functions induced by antagomir-16-1 were all significantly reversed by HSP70 silencing. The present findings indicated that TPL may be a potential therapeutic option for postoperative anastomosis fibrosis of patients with CD. The miR-16-1/HSP70 pathway had a substantial role in the inhibitory effects of TPL on migration, proliferation and ECM synthesis rate of fibroblasts from strictured anastomosis tissues.

Effects of AT1 receptor antagonism on interstitial and ultrastructural remodeling of heart in response to a hypercaloric diet

Palatable hypercaloric feeding has been associated with angiotensin-II type 1 receptor (AT1R) stimulation and cardiac remodeling. This study analyzed whether AT1R antagonism attenuates cardiac remodeling in rats subjected to a palatable hypercaloric diet. Male Wistar-Kyoto rats were subjected to a commercial standard rat chow (CD) or a palatable hypercaloric diet (HD) for 35 weeks and then allocated into four groups: CD, CL, HD, and HL; L groups received losartan in drinking water (30 mg/kg/day) for 5 weeks. Body weight, adiposity, and glycemia were evaluated. The cardiovascular study included echocardiography, and myocardial morphometric and ultrastructural evaluation. Myocardial collagen isoforms Type I and III were analyzed by Western blot. Both HD and HL had higher adiposity than their respective controls. Cardiomyocyte cross-sectional-area (CD 285 ± 49; HD 344 ± 91; CL 327 ± 49; HL 303 ± 49 μm2 ) and interstitial collagen fractional area were significantly higher in HD than CD and unchanged by losartan. HD showed marked ultrastructural alterations such as myofilament loss, and severe mitochondrial swelling. CL presented higher Type I collagen expression when compared to CD and HL groups. The ultrastructural changes and type I collagen expression were attenuated by losartan in HL. Losartan attenuates systolic dysfunction and ultrastructural abnormalities without changing myocardial interstitial remodeling in rats subjected to a palatable hypercaloric diet.

Mitochondrial regulation of cardiac aging

Aging is associated with progressive decline in cardiac structure and function. Accumulating evidence in model organisms and humans links cardiac aging to mitochondrial regulation, encompassing a complex interplay of mitochondrial morphology, mitochondrial ROS, mitochondrial DNA mutations, mitochondrial unfolded protein response, nicotinamide adenine dinucleotide levels and sirtuins, as well as mitophagy. This review summarizes the recent discoveries on the mitochondrial regulation of cardiac aging and the possible molecular mechanisms underlying the anti-aging effects, as well as the potential interventions that alleviate aging-related cardiac diseases and attenuate cardiac aging via the regulation of mitochondria.

Resveratrol Inhibits the TGF-β1-Induced Proliferation of Cardiac Fibroblasts and Collagen Secretion by Downregulating miR-17 in Rat

Myocardial fibrosis (MF) can cause heart remodeling and it is an independent risk factor for malignant arrhythmias, sudden cardiac death, and other malignant cardiovascular events. It is often characterized by myocardial interstitial collagen deposition and hyperproliferation of cardiac fibroblasts (CFs). The transforming growth factor-β1 (TGF-β1) is the most influential profibrogenic factor. Resveratrol (RSV) is an active polyphenol substance that inhibits myocardial fibrosis. The mechanism of RSV-mediated inhibition of the proliferation of CFs at the microRNA level is not fully understood. We used TGF-β1 to induce CFs proliferation to simulate the pathogenesis of myocardial fibrosis. Neonatal rat CFs were treated with TGF-β1 in the presence or absence of resveratrol. Cell proliferation was measured using the CCK-8 and EdU assay. Collagen secretion was measured using hydroxyproline kit. Further, qPCR analysis was performed to determine microRNA levels after TGF-β1 or resveratrol treatment. To identify the target gene for miR-17, miR-17 was overexpressed or silenced, and the mRNA and protein levels of Smad7 were assessed. The effects of miR-17 silencing or Smad7 overexpression on cell proliferation and collagen secretion were also examined. Resveratrol treatment significantly decreased the TGF-β1-induced CF proliferation and collagen secretion. Resveratrol also decreased the levels of miR-17, miR-34a, and miR-181a in TGF-β1-treated CFs. Overexpression of miR-17 decreased the Smad7 mRNA and protein levels while silencing miR-17 increased them. Additionally, silencing miR-17 or overexpressing Smad7 decreased the TGF-β1-induced CFs proliferation and collagen secretion. In conclusion, resveratrol inhibits TGF-β1-induced CFs proliferation and collagen secretion. This inhibitory effect of resveratrol is orchestrated by the downregulation of miR-17 and the regulation of Smad7.

Ghrelin Ameliorates Angiotensin II-Induced Myocardial Fibrosis by Upregulating Peroxisome Proliferator-Activated Receptor Gamma in Young Male Rats

Angiotensin (Ang) II contributes to the formation and development of myocardial fibrosis. Ghrelin, a gut peptide, has demonstrated beneficial effects against cardiovascular disease. In the present study, we explored the effect and related mechanism of Ghrelin on myocardial fibrosis in Ang II-infused rats. Adult Sprague-Dawley (SD) rats were divided into 6 groups: Control, Ang II (200ng/kg/min, microinfusion), Ang II+Ghrelin (100 μg/kg, subcutaneously twice daily), Ang II+Ghrelin+GW9662 (a specific PPAR-γ inhibitor, 1 mg/kg/d, orally), Ang II+GW9662, and Ghrelin for 4 wks. In vitro, adult rat cardiac fibroblasts (CFs) were pretreated with or without Ghrelin, Ghrelin+GW9662, or anti-Transforming growth factor (TGF)-β1 antibody and then stimulated with or without Ang II (100 nmol/L) for 24 h. Ang II infusion significantly increased myocardial fibrosis, expression of collagen I, collagen III, and TGF-β1, as well as TGF-β1 downstream proteins p-Smad2, p-Smad3, TRAF6, and p-TAK1 (all p<0.05). Ghrelin attenuated these effects. Similar results were seen in Ang II-stimulated rat cardiac fibroblasts in vitro. In addition, Ghrelin upregulated PPAR-γ expression in vivo and in vitro, and treatment with GW9662 counteracted the effects of Ghrelin. In conclusion, Ghrelin ameliorated Ang II-induced myocardial fibrosis by upregulating PPAR-γ and in turn inhibiting TGF-β1signaling.

Resveratrol Ameliorates Cardiac Dysfunction by Inhibiting Apoptosis via the PI3K/Akt/FoxO3a Pathway in a Rat Model of Diabetic Cardiomyopathy

The aim of this study was to explore the effect and mechanism of action of resveratrol (RSV) on cardiac function in diabetic cardiomyopathy (DCM). Hyperglycemia-induced apoptosis contributes to the pathogenic changes in DCM. RSV treatment inhibited high glucose-induced apoptosis of neonatal rat ventricular myocytes. Additionally, high glucose decreased cell viability, prevented serine-threonine kinase (Akt) and FoxO3a phosphorylation, and suppressed cytoplasmic translocation of FoxO3a. However, these effects of apoptosis were reversed by 10 μM of RSV. The PI3K inhibitor LY294002 abolished the RSV protective effect in vitro. RSV (5 or 50 mg·kg·d orally for 8 weeks) prevented the deterioration of cardiac function and structural cardiomyopathy in a streptozotocin-induced rat model of diabetes and reduced apoptosis in diabetic myocardium. Furthermore, it restored streptozotocin-impaired phosphorylation of Akt and FoxO3a (p-Akt and p-FoxO3a) and suppressed nuclear translocation of FoxO3a in vivo. Together, these data indicate that RSV has therapeutic potential against DCM by inhibiting apoptosis via the PI3K/Akt/FoxO3a pathway.

Sustained β-AR stimulation induces synthesis and secretion of growth factors in cardiac myocytes that affect on cardiac fibroblast activation

Paracrine factors, including growth factors and cytokines, released from cardiac myocytes following β-adrenergic receptor (β-AR) stimulation regulate cardiac fibroblasts. Activated cardiac fibroblasts have the ability to increase collagen synthesis, cell proliferation and myofibroblast differentiation, leading to cardiac fibrosis. However, it is unknown which β-AR subtypes and signaling pathways mediate the upregulation of paracrine factors in cardiac myocytes. In this study, we demonstrated that sustained stimulation of β-ARs significantly induced synthesis and secretion of growth factors, including connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF), via the cAMP-dependent and protein kinase A (PKA)-dependent pathways. In addition, isoproterenol (ISO)-mediated synthesis and secretion of CTGF and VEGF through the β₁-AR and β₂-AR subtypes. Paracrine factors released by cardiac myocytes following sustained β-AR stimulation are necessary for the induction of cell proliferation and synthesis of collagen I, collagen III and α-smooth muscle actin (α-SMA) in cardiac fibroblasts, confirming that β-AR overstimulation of cardiac myocytes induces cardiac fibrosis by releasing several paracrine factors. These effects can be antagonized by β-blockers, including atenolol, metoprolol, and propranolol. Thus, the use of β-blockers may have beneficial effects on the treatment of myocardial fibrosis in patients with heart failure.

Chronic Resveratrol Treatment Inhibits MRC5 Fibroblast SASP-Related Protumoral Effects on Melanoma Cells

Cellular senescence is related to organismal aging and is observed after DNA damaging cancer therapies, that induce tumor-suppressive modifications, but it is characterized by a strong increase in secreted factors, termed the "senescence-associated secretory phenotype" (SASP). Particularly, SASP from stroma senescent fibroblasts creates a cancer-favoring microenvironment, providing targets for anti-cancer interventions. In the present article, chronic treatment (5 weeks) with 5 µM resveratrol has been used to modulate senescence-related protumoral features of MRC5 fibroblasts, reducing SASP-related interleukins IL1α, IL1β, IL6, and IL8; transforming-growth-factor-β (TGFβ); matrix metallo-proteinases MMP3 and MMP2; urokinase plasminogen activator (uPA); receptor proteins uPAR, IL6R, insulin growth factor receptor-1 (IGF-1R), TGFβ-R2, and CXCR4. The cellular nuclear-factor-kB (NF-kB) protein level was also reduced, confirming its role in the induction of SASP. Resveratrol pretreated MRC5 fibroblasts were resistant to activation by TGFβ. Resveratrol treatment of senescent MRC5 induced the production of conditioned media (CM) which counteracted the protumoral effect of senescent CM on A375 and A375-M6 melanoma cell proliferation and invasiveness, and reduced the expression of epithelial-to-mesenchymal transition markers related to malignant features. This experimental approach proposes a treatment that targets the senescent stromal cell phenotype to induce an anti-tumor hosting microenvironment, which is suitable for both preventive and therapeutic purposes.

Enhanced expression and phosphorylation of Sirt7 activates smad2 and ERK signaling and promotes the cardiac fibrosis differentiation upon angiotensin-II stimulation

Cardiac fibroblasts (CFs) phenotypic conversion to myofibroblasts (MFs) represents a crucial event in cardiac fibrosis that leads to impaired cardiac function. However, regulation of this phenotypic transformation remains unclear. Here, we showed that sirtuin-7 (Sirt7) plays an important role in the regulation of MFs differentiation. Sirt7 expression and phosphorylation were upregulated in CFs upon angiotensin-II (Ang-II) stimulation. Sirt7 depletion by siRNA in CFs resulted in decreased cell proliferation and extracellular matrix (ECM) deposition. Further, examination of Sirt7-depleted CFs demonstrated significantly lower expression of α-smooth muscle actin (α-SMA), the classical marker of MFs differentiation, and decreased formation of focal adhesions. Moreover, overexpression of Sirt7 increased α-SMA expression in Ang-II treated CFs and exacerbated Ang-II-induced MFs differentiation. Moreover, Sirt7 depletion could largely reverse Ang-II induced increase of nuclear translocalization and activity of smad2 and extracellular regulated kinases (ERK) in CFs. Importantly, the increased differentiation of CFs to MFs was also abolished by smad2 siRNA or U0126. Our findings reveal a novel role of Sirt7 and its phosphorylation in the phenotypic conversion of CFs to MFs and might lead to the development of new therapeutic and prognostic tools for cardiac fibrosis.

Activation of mutated TRPA1 ion channel by resveratrol in human prostate cancer associated fibroblasts (CAF)

Previous studies showed the effects of resveratrol (RES) on several cancer cells, including prostate cancer (PCa) cell apoptosis without taking into consideration the impact of the tumor microenvironment (TME). The TME is composed of cancer cells, endothelial cells, blood cells, and cancer-associated fibroblasts (CAF), the main source of growth factors. The latter cells might modify in the TME the impact of RES on tumor cells via secreted factors. Recent data clearly show the impact of CAF on cancer cells apoptosis resistance via secreted factors. However, the effects of RES on PCa CAF have not been studied so far. We have investigated here for the first time the effects of RES on the physiology of PCa CAF in the context of TME. Using a prostate cancer CAF cell line and primary cultures of CAF from prostate cancers, we show that RES activates the N-terminal mutated Transient Receptor Potential Ankyrin 1 (TRPA1) channel leading to an increase in intracellular calcium concentration and the expression and secretion of growth factors (HGF and VEGF) without inducing apoptosis in these cells. Interestingly, in the present work, we also show that when the prostate cancer cells were co-cultured with CAF, the RES-induced cancer cell apoptosis was reduced by 40%, an apoptosis reduction canceled in the presence of the TRPA1 channel inhibitors. The present work highlights CAF TRPA1 ion channels as a target for RES and the importance of the channel in the epithelial-stromal crosstalk in the TME leading to resistance to the RES-induced apoptosis.

Sirtuin 3 Deregulation Promotes Pulmonary Fibrosis

Oxidative stress leads to alveolar epithelial cell injury and fibroblast-myofibroblast differentiation (FMD), key events in the pathobiology of pulmonary fibrosis (PF). Sirtuin 3 (SIRT3) is a mitochondrial protein deacetylase regulator of antioxidant response and mitochondrial homeostasis. Here, we demonstrate reduced SIRT3 expression in the lungs of old mice compared to young mice, as well as in two murine models of PF. The analysis of the pattern of SIRT3 expression in the lungs of patients with PF revealed low SIRT3 staining within the fibrotic regions. We also demonstrated, using murine models of PF and human lung fibroblasts, that reduced SIRT3 expression in response to transforming growth factor beta 1 (TGFβ1) promotes acetylation (inactivation) of major oxidative stress response regulators, such as SOD2 and isocitrate dehydrogenase 2. Reduction of SIRT3 in human lung fibroblasts promoted FMD. By contrast, overexpression of SIRT3 attenuated TGFβ1-mediated FMD and significantly reduced the levels of SMAD family member 3 (SMAD3). Resveratrol induced SIRT3 expression and ameliorated acetylation changes induced by TGFβ1. We demonstrated that SIRT3-deficient mice are more susceptible to PF compared to control mice, and concomitantly exhibit enhanced SMAD3 expression. Collectively, these data define a SIRT3/TGFβ1 interaction during aging that may play a significant role in the pathobiology of PF.

Disparate Effects of Stilbenoid Polyphenols on Hypertrophic Cardiomyocytes In Vitro vs. in the Spontaneously Hypertensive Heart Failure Rat

Stilbenoids are bioactive polyphenols, and resveratrol (trans-3,5,4′-trihydroxystilbene) is a representative stilbenoid that reportedly exerts cardioprotective actions. As resveratrol exhibits low oral bioavailability, we turned our attention to other stilbenoid compounds with a history of medicinal use and/or improved bioavailability. We determined the effects of gnetol (trans-3,5,2′,6′-tetrahydroxystilbene) and pterostilbene (trans-3,5-dimethoxy-4′-hydroxystilbene) on cardiac hypertrophy. In vitro, gnetol and pterostilbene prevented endothelin-1-induced indicators of cardiomyocyte hypertrophy including cell enlargement and protein synthesis. Gnetol and pterostilbene stimulated AMP-activated protein kinase (AMPK), and inhibition of AMPK, using compound C or shRNA knockdown, abolished these anti-hypertrophic effects. In contrast, resveratrol, gnetol, nor pterostilbene reduced blood pressure or hypertrophy in the spontaneously hypertensive heart failure (SHHF) rat. In fact, AMPK levels were similar between Sprague-Dawley and SHHF rats whether treated by stilbenoids or not. These data suggest that the anti-hypertrophic actions of resveratrol (and other stilbenoids?) do not extend to the SHHF rat, which models heart failure superimposed on hypertension. Notably, SHHF rat hearts exhibited prolonged isovolumic relaxation time (an indicator of diastolic dysfunction), and this was improved by stilbenoid treatment. In conclusion, stilbenoid-based treatment as a viable strategy to prevent pathological cardiac hypertrophy, a major risk factor for heart failure, may be context-dependent and requires further study.

Targeting extracellular matrix remodeling in disease: Could resveratrol be a potential candidate?

Disturbances of extracellular matrix homeostasis are associated with a number of pathological conditions. The ability of extracellular matrix to provide contextual information and hence control the individual or collective cellular behavior is increasingly being recognized. Hence, newer therapeutic approaches targeting extracellular matrix remodeling are widely investigated. We reviewed the current literature showing the effects of resveratrol on various aspects of extracellular matrix remodeling. This review presents a summary of the effects of resveratrol on extracellular matrix deposition and breakdown. Mechanisms of action of resveratrol in extracellular matrix deposition involving growth factors and their signaling pathways are discussed. Involvement of phosphoinositol-3-kinase/Akt and mitogen-activated protein kinase pathways and role of transcription factors and sirtuins on the effects of resveratrol on extracellular matrix homeostasis are summarized. It is evident from the literature presented in this review that resveratrol has significant effects on both the synthesis and breakdown of extracellular matrix. The major molecular targets of the action of resveratrol are growth factors and their signaling pathways, phosphoinositol-3-kinase/Akt and mitogen-activated protein kinase pathways, transcription factors, and SIRT-1. The effects of resveratrol on extracellular matrix and the molecular targets appear to be related to experimental models, experimental environment as well as the doses.

Resveratrol Ameliorates Diabetes-Induced Cardiac Dysfunction Through AT1R-ERK/p38 MAPK Signaling Pathway

The present study was to determine the preventive effect of resveratrol (Res) on diabetes-induced cardiac dysfunction and the possible signaling pathway involved. Diabetes was induced in rats by injection of streptozotocin (STZ) at 45 mg/kg. The animals were randomly divided into three groups (10 rats/group): normal group, diabetes groups with or without Res (80 mg/kg) treatment. Biochemistry, cardiac function and fibrosis were detected. Moreover, pro-inflammatory cytokines were evaluated, and heart tissues were homogenized for western blot analysis to analyze the possible mechanisms. The results indicated that Res might regulate glucose and lipid metabolism, ameliorate cardiac function and fibrosis response in STZ-induced diabetic rats. The protective effects were consistent with the inhibition of inflammatory factors such as TNF-α, IL-6 and IL-1β. In addition, Res favorably shifted STZ-induced AT1R, ERK1/2 and p38 MAPK activation in rat heart. In conclusion, the results suggested that Res attenuated diabetes-induced cardiac dysfunction, and the effects were associated with attenuation inflammatory response and down-regulation of AT1R-ERK/p38 MAPK signaling pathway.

The role of myofibroblasts in wound healing

The importance of proper skin wound healing becomes evident when our body's repair mechanisms fail, leading to either non-healing (chronic) wounds or excessive repair (fibrosis). Chronic wounds are a tremendous burden for patients and global healthcare systems and are on the rise due to their increasing incidence with age and diabetes. Curiously, these same risk factors also sign responsible for the development of hypertrophic scarring and organ fibrosis. Activated repair cells - myofibroblasts - are the main producers and organizers of extracellular matrix which is needed to restore tissue integrity after injury. Too many myofibroblasts working for too long cause tissue contractures that ultimately obstruct organ function. Insufficient myofibroblast activation and activities, in turn, prevents normal wound healing. This short review puts a spotlight on the myofibroblast for those who seek therapeutic targets in the context of dysregulated tissue repair. "Keep your myofibroblasts in balance" is the message.

Activin A stimulates the proliferation and differentiation of cardiac fibroblasts via the ERK1/2 and p38-MAPK pathways

Activin A is a key regulator of cardiac fibrosis. However, little is known about the mechanisms by which it contributes to cardiac fibrosis. Our study explored the effects of activin A on proliferation and differentiation of adult rat cardiac fibroblasts (CFs) via the activin A receptor, activin receptor-like kinase 4 (ALK4). CF proliferation was measured by CCK8 and EdU assays, while differentiation, fibrosis and signaling were measured by western blot analysis of α-smooth muscle actin, collagen type I, phosphorylated extracellular signal-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (p38-MAPK) expression. Activin A levels were measured by ELISA and western blot analysis. We demonstrated that CFs express activin A and its expression was significantly enhanced by angiotensin II (Ang II), but follistatin (activin A inhibitor) significantly reversed Ang II-induced activin A upregulation, CF proliferation, differentiation, collagen type I expression as well as ERK1/2 and p38-MAPK pathways activation. Conversely, recombinant activin A largely increased these parameters in both the presence and absence of Ang II. Interestingly, p38-MAPK (SB203580) and ALK4 (SB431542) inhibitors significantly reduced all activin A-mediated responses; however, an ERK1/2 inhibitor (PD98059) could only significantly reduce CF proliferation and collagen type I expression but not differentiation. Importantly, the most significant effects were observed in the presence vs. absence of Ang II. Thus, activin A promotes basal and Ang II-induced CF proliferation and differentiation via ALK4, and the effects are partly mediated through the ERK1/2 and p38-MAPK pathways. These data suggest that activin A is a potential therapeutic target for cardiac fibrosis.

Human Endomyocardial Biopsy Specimen-Derived Stromal Cells Modulate Angiotensin II-Induced Cardiac Remodeling

: Cardiac-derived adherent proliferating cells (CardAPs) are cells derived from human endomyocardial biopsy specimens; they share several properties with mesenchymal stromal cells. The aims of this study were to evaluate whether intramyocardial injection of CardAPs modulates cardiac fibrosis and hypertrophy in a mouse model of angiotensin II (Ang II)-induced systolic heart failure and to analyze underlying mechanisms. Intramyocardial application of 200,000 CardAPs improved left ventricular function. This was paralleled by a decline in left ventricular remodeling, as indicated by a reduction in cardiac fibrosis and hypertrophy. CardAPs reduced the ratio of the left ventricle to body weight and cardiac myosin expression (heavy chain), and decreased the Ang II-induced phosphorylation state of the cardiomyocyte hypertrophy mediators Akt, extracellular-signal regulated kinase (ERK) 1, and ERK2. In accordance with the antifibrotic and antihypertrophic effects of CardAPs shown in vivo, CardAP supplementation with cardiac fibroblasts decreased the Ang II-induced reactive oxygen species production, α-SMA expression, fibroblast proliferation, and collagen production. Coculture of CardAPs with HL-1 cardiomyocytes downregulated the Ang II-induced expression of myosin in HL-1. All antifibrotic and antihypertrophic features of CardAPs were mediated in a nitric oxide- and interleukin (IL)-10-dependent manner. Moreover, CardAPs induced a systemic immunomodulation, as indicated by a decrease in the activity of splenic mononuclear cells and an increase in splenic CD4CD25FoxP3, CD4-IL-10, and CD8-IL-10 T-regulatory cells in Ang II mice. Concomitantly, splenocytes from Ang II CardAPs mice induced less collagen in fibroblasts compared with splenocytes from Ang II mice. We conclude that CardAPs improve Ang II-induced cardiac remodeling involving antifibrotic and antihypertrophic effects via paracrine actions and immunomodulatory properties.

SIGNIFICANCE

Despite effective pharmacological treatment with angiotensin II type I receptor antagonists or angiotensin II-converting enzyme inhibitors, morbidity and mortality associated with heart failure are still substantial, prompting the search of novel therapeutic strategies. There is accumulating evidence supporting the use of cell therapy for cardiac repair. This study demonstrates that cells derived from human endomyocardial biopsies, cardiac-derived adherent proliferating cells (CardAPs), have the potential to reduce angiotensin II-induced cardiac remodeling and improve left ventricular function in angiotensin II mice. The mechanism involves antifibrotic and antihypertrophic effects via paracrine actions and immunomodulatory properties. These findings support the potential of CardAPs for the treatment of heart failure.

The evidence for natural therapeutics as potential anti-scarring agents in burn-related scarring

Though survival rate following severe thermal injuries has improved, the incidence and treatment of scarring have not improved at the same speed. This review discusses the formation of scars and in particular the formation of hypertrophic scars. Further, though there is as yet no gold standard treatment for the prevention or treatment of scarring, a brief overview is included. A number of natural therapeutics have shown beneficial effects both in vivo and in vitro with the potential of becoming clinical therapeutics in the future. These natural therapeutics include both plant-based products such as resveratrol, quercetin and epigallocatechin gallate as examples and includes the non-plant-based therapeutic honey. The review also includes potential mechanism of action for the therapeutics, any recorded adverse events and current administration of the therapeutics used. This review discusses a number of potential 'treatments' that may reduce or even prevent scarring particularly hypertrophic scarring, which is associated with thermal injuries without compromising wound repair.

Resveratrol shows neuronal and vascular-protective effects in older, obese, streptozotocin-induced diabetic rats

Diabetes-induced CVD is the most significant complication of prolonged hyperglycaemia. The aim of this study was to determine whether resveratrol, a polyphenol antioxidant compound, when administered at a dose that can be reasonably obtained through supplementation could prevent the development of cardiovascular complications in older, obese, diabetic rats. Diabetes was induced in 6-month old, obese, male Wistar rats via a single intravenous dose of streptozotocin (65 mg/kg). Randomly selected animals were administered resveratrol (2 mg/kg) via oral gavage daily for 8 weeks. Body weights, blood glucose levels, food intake and water consumption were monitored, and assessments of vascular reactivity, tactile allodynia and left ventricular function were performed. Resveratrol therapy significantly improved tactile allodynia and vascular contractile functionality in diabetic rats (P<0·05). There were no significant changes in standardised vasorelaxation responses, plasma glucose concentrations, water consumption, body weight, left ventricular hypertrophy, kidney hypertrophy, heart rate or left ventricular compliance with resveratrol administration. Resveratrol-mediated improvements in vascular and nerve function in old, obese, diabetic rats were associated with its reported antioxidant effects. Resveratrol did not improve cardiac function nor mitigate the classic clinical symptoms of diabetes mellitus (i.e. hyperglycaemia, polydypsia and a failure to thrive). This suggests that supplementation with resveratrol at a dose achievable with commercially available supplements would not produce significant cardioprotective effects in people with diabetes mellitus.

αKlotho and Chronic Kidney Disease

Alpha-Klotho (αKlotho) protein is encoded by the gene, Klotho, and functions as a coreceptor for endocrine fibroblast growth factor-23. The extracellular domain of αKlotho is cleaved by secretases and released into the circulation where it is called soluble αKlotho. Soluble αKlotho in the circulation starts to decline in chronic kidney disease (CKD) stage 2 and urinary αKlotho in even earlier CKD stage 1. Therefore soluble αKlotho is an early and sensitive marker of decline in kidney function. Preclinical data from numerous animal experiments support αKlotho deficiency as a pathogenic factor for CKD progression and extrarenal CKD complications including cardiac and vascular disease, hyperparathyroidism, and disturbed mineral metabolism. αKlotho deficiency induces cell senescence and renders cells susceptible to apoptosis induced by a variety of cellular insults including oxidative stress. αKlotho deficiency also leads to defective autophagy and angiogenesis and promotes fibrosis in the kidney and heart. Most importantly, prevention of αKlotho decline, upregulation of endogenous αKlotho production, or direct supplementation of soluble αKlotho are all associated with attenuation of renal fibrosis, retardation of CKD progression, improvement of mineral metabolism, amelioration of cardiac function and morphometry, and alleviation of vascular calcification in CKD. Therefore in rodents, αKlotho is not only a diagnostic and prognostic marker for CKD but the enhancement of endogenous or supplement of exogenous αKlotho are promising therapeutic strategies to prevent, retard, and decrease the comorbidity burden of CKD.

Effects of Peroxisome Proliferator-Activated Receptor-δ Agonist on Cardiac Healing after Myocardial Infarction

Peroxisome proliferator-activated receptor-delta (PPAR-δ)-dependent signaling is associated with rapid wound healing in the skin. Here, we investigated the therapeutic effects of PPAR-δ-agonist treatment on cardiac healing in post-myocardial infarction (MI) rats. Animals were assigned to the following groups: sham-operated control group, left anterior descending coronary artery ligation (MI) group, or MI with administration of the PPAR-δ agonist GW610742 group. GW610742 (1 mg/kg) was administrated intraperitoneally after the operation and repeated every 3 days. Echocardiographic data showed no differences between the two groups in terms of cardiac function and remodeling until 4 weeks. However, the degrees of angiogenesis and fibrosis after MI were significantly higher in the GW610742-treated rats than in the untreated MI rats at 1 week following MI, which changes were not different at 2 weeks after MI. Naturally, PPAR-δ expression in infarcted myocardium was highest increased in 3 day after MI and then disappeared in 14 day after MI. GW610742 increased myofibroblast differentiation and transforming growth factor-beta 2 expression in the infarct zone at 7 days after MI. GW610742 also increased bone marrow-derived mesenchymal stem cell (MSC) recruitment in whole myocardium, and increased serum platelet-derived growth factor B, stromal-derived factor-1 alpha, and matrix metallopeptidase 9 levels at day 3 after MI. PPAR-δ agonists treatment have the temporal effect on early fibrosis of infarcted myocardium, which might not sustain the functional and structural beneficial effect.

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.

Anti-proliferative effect of the extract of Guangzao (Fructus Choerospondiatis) on cultured rat cardiac fibroblasts

OBJECTIVE

To ascertain if total flavonoids of Guangzao (Fructus Choerospondiatis) (TFFC) extracted from Guangzao (Fructus Choerospondiatis) can inhibit angiotensin II-induced proliferation of cardiac fibroblasts (CFs).

METHODS

CFs were cultured by the differential attachment method. A model of cell proliferation was established by stimulation with Ang II. Cardiac fibroblasts growth was determined using a hemocytometer. Cell proliferation was detected by methyl thiazole tetrazolium. Lactate dehydrogenase activity was measured by chemical colorimetric method.

RESULTS

Proliferation of TFFC-treated (25, 50, 100 mg/L) fibroblasts was significantly less than that of cells in the angiotensin II group (P < 0.01), and TFFC inhibited proliferation in a dose-dependent manner. These inhibitory effects were partly blocked by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) and 1H-[1,2,4]-oxadiazole-[4,3-a]-quinoxalin-1-one (ODQ).

CONCLUSION

TFFC inhibited angiotensin II-induced proliferation of cardiac fibroblasts via a mechanism that probably involves activation of the NO-cyclic guanosine monophosphate signaling pathway.