Protective effect of lycopene on cardiac function and myocardial fibrosis after acute myocardial infarction in rats via the modulation of p38 and MMP-9

Inhibitory effect of microRNA-21 on pathways and mechanisms involved in cardiac fibrosis development

Cardiac fibrosis is a pivotal cardiovascular disease (CVD) process and represents a notable health concern worldwide. While the complex mechanisms underlying CVD have been widely investigated, recent research has highlighted microRNA-21's (miR-21) role in cardiac fibrosis pathogenesis. In this narrative review, we explore the molecular interactions, focusing on the role of miR-21 in contributing to cardiac fibrosis. Various signaling pathways, such as the RAAS, TGF-β, IL-6, IL-1, ERK, PI3K-Akt, and PTEN pathways, besides dysregulation in fibroblast activity, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs cause cardiac fibrosis. Besides, miR-21 in growth factor secretion, apoptosis, and endothelial-to-mesenchymal transition play crucial roles. miR-21 capacity regulatory function presents promising insights for cardiac fibrosis. Moreover, this review discusses numerous approaches to control miR-21 expression, including antisense oligonucleotides, anti-miR-21 compounds, and Notch signaling modulation, all novel methods of cardiac fibrosis inhibition. In summary, this narrative review aims to assess the molecular mechanisms of cardiac fibrosis and its essential miR-21 function.

Lycopene abolishes palmitate-mediated myocardial inflammation in female Wistar rats via modulation of lipid metabolism, NF-κB signalling pathway, and augmenting the antioxidant systems

BACKGROUND AND AIMS

Obesity-related heart failure is exacerbated by excessive intake of saturated fats such as palmitate (PA). Lycopene (LYC) possesses anti-lipidemic, antioxidant, cytoprotective, and anti-inflammatory effects. This study, therefore, evaluated the impact of LYC against PA-invoked cardiotoxicity.

METHODS AND RESULTS

Thirty-six female rats were equally divided into six groups: control; PA (5 mM); PA + LYC (24 mg/kg); PA + LYC (48 mg/kg); LYC (24 mg/kg); and LYC (48 mg/kg). The PA was administered five times weekly for seven weeks, while the LYC was given for the last two weeks. Lipids in the blood and the heart were estimated, as were oxidative stress and antioxidant indices, cardiac function, inflammation, and histology. Palmitate overload occasioned a significant (p < 0.05) increase in cardiac cholesterol (50%), phospholipids (19%), and non-esterified fatty acids (40%). However, triglyceride levels decreased (38%). Furthermore, malondialdehyde (45%), hydrogen peroxide (33%) levels and myeloperoxidase activity increased (79%). Also, cardiac gamma-glutamyl transferase (50%), serum creatine kinase activities (1.34 folds), NF-kB, interleukin1β, and interleukin-6 mRNA expression increased in the PA group relative to the control. In contrast, reduced glutathione (13%) and nitric oxide levels (22%), interleukin-10 mRNA expression, cardiac creatine kinase (35%), lactate dehydrogenase (33%), aspartate, and alanine transaminase activities decreased markedly (15- and 10%, respectively). Also, PA caused hyperemia, congestion of the cardiac interstitium, and infiltration of inflammatory cells. However, treatment with LYC reversed the features of cardiotoxicity and histological complications caused by PA. These observations are likely because LYC has anti-inflammatory, antioxidant, and cytoprotective properties.

CONCLUSION

Thus, LYC might be an appropriate remedy to manage PA-induced cardiotoxicity in female rats.

Astragalus propinquus schischkin and Salvia miltiorrhiza bunge promote angiogenesis to treat myocardial ischemia via Ang-1/Tie-2/FAK pathway

Astragalus propinquus Schischkin and Salvia miltiorrhiza Bunge (AS) have been clinically used as adjunctive drugs in the treatment of myocardial ischemia (MI). However, the effect and mechanism of AS on MI have yet to be fully recognized. Here, we explored the cardioprotective effect of their combined use, and the mechanism of promoting angiogenesis through pericyte recruitment. Our data revealed that AS reduced MI and protects cardiac function. AS-treated MI mice exhibited reduced ST-segment displacement and repolarization time, increased ejection fraction, and less BNP and NT-proBNP expression. Pathological studies showed that, AS reduced the area of infarcted myocardium and slowed down the progress of cardiac remodelling and fibrosis. In addition, AS increased the content of platelet-derived growth factor receptors β (PDGFR-β), platelet endothelial cell adhesion molecule-1 (CD31) and angiogenesis-related proteins including vascular endothelial cadherin (VE-cadherin), Vascular Endothelial Growth Factor (VEGF) and transforming growth factor β (TGF-β). Moreover, these botanical drugs upregulated the expression of Angiopoietin-1 (Ang-1), phosphorylated angiopoietin-1 receptor (p-Tie-2), focal adhesion kinase (FAK) and growth factor receptor bound protein 7 (GRB7), indicating that the cardioprotection-related angiogenesis effect was related to pericyte recruitment, which may be through Ang-1/Tie-2/FAK pathway. In summary, AS can treat MI by protecting cardiac function, attenuating cardiac pathological changes, and hindering the progression of heart failure, which is related to angiogenesis after pericyte recruitment. Therefore, AS at a certain dose can be a promising treatment for MI with broad application prospects.

Lycopene: a therapeutic strategy against coronavirus disease 19 (COVID- 19)

Lycopene is a group of phytochemicals found in nature, primarily in fruits and vegetables. Lycopene is thought to protect against a variety of diseases attributed to its antioxidant capabilities. Lycopene has anti-inflammatory, anti-cancer, and immunity-boosting qualities, among other biological and pharmacological benefits. COVID-19 (coronavirus disease 19) is an infectious disease caused by the SARS-CoV-2 virus, which has recently emerged as one of the world's leading causes of death. Patients may be asymptomatic or show signs of respiratory, cytokine release syndrome, gastrointestinal, or even multiple organ failure, all of which can lead to death. In COVID-19, inflammation, and cytokine storm are the key pathogenic mechanisms, according to SARS-CoV-2 infection symptoms. ARDS develops in some vulnerable hosts, which is accompanied by an inflammatory "cytokine syndrome" that causes lung damage. Immunological and inflammatory markers were linked to disease severity in mild and severe COVID-19 cases, implying that inflammatory markers, including IL-6, CRP, ESR, and PCT were significantly linked with COVID-19 severity. Patients with severe illness have reduced levels of several immune subsets, including CD4 + T, NK, and CD8 + cells. As a result, lycopene can be commended for bolstering physiological defenses against COVID-19 infections.

Effects of Lycopene Attenuating Injuries in Ischemia and Reperfusion

Tissue and organ ischemia can lead to cell trauma, tissue necrosis, irreversible damage, and death. While intended to reverse ischemia, reperfusion can further aggravate an ischemic injury (ischemia-reperfusion injury, I/R injury) through a range of pathologic processes. An I/R injury to one organ can also harm other organs, leading to systemic multiorgan failure. A type of carotenoid, lycopene, has been shown to treat and prevent many diseases (e.g., rheumatoid arthritis, cancer, diabetes, osteoporosis, male infertility, neurodegenerative diseases, and cardiovascular disease), making it a hot research topic in health care. Some recent researches have suggested that lycopene can evidently ameliorate ischemic and I/R injuries to many organs, but few clinical studies are available. Therefore, it is essential to review the effects of lycopene on ischemic and I/R injuries to different organs, which may help further research into its potential clinical applications.

Cardiovascular Disease and Possible Ways in Which Lycopene Acts as an Efficient Cardio-Protectant against Different Cardiovascular Risk Factors

Foods rich in antioxidants such as lycopene have a major role in maintaining cardiac health. Lycopene, 80% of which can be obtained by consuming a common vegetable such as tomato, can prevent the disturbances that contribute to cardiovascular disease (CVD). The present work begins with a brief introduction to CVD and lycopene and its various properties such as bioavailability, pharmacokinetics, etc. In this review, the potential cardio-protective effects of lycopene that reduce the progression of CVD and thrombotic complications are detailed. Further, the protective effects of lycopene including in vitro, in vivo and clinical trials conducted on lycopene for CVD protective effects are explained. Finally, the controversial aspect of lycopene as a protective agent against CVD and toxicity are also mentioned.

Lycopene in the Prevention of Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of human mortality worldwide. Oxidative stress and inflammation are pathophysiological processes involved in the development of CVD. That is why bioactive food ingredients, including lycopene, are so important in their prevention, which seems to be a compound increasingly promoted in the diet of people with cardiovascular problems. Lycopene present in tomatoes and tomato products is responsible not only for their red color but also for health-promoting properties. It is characterized by a high antioxidant potential, the highest among carotenoid pigments. Mainly for this reason, epidemiological studies show a number of favorable properties between the consumption of lycopene in the diet and a reduced risk of cardiovascular disease. While there is also some controversy in research into its protective effects on the cardiovascular system, growing evidence supports its beneficial role for the heart, endothelium, blood vessels, and health. The mechanisms of action of lycopene are now being discovered and may explain some of the contradictions observed in the literature. This review aims to present the current knowledge in recent years on the preventive role of lycopene cardiovascular disorders.

The effect of lycopene on serum level of cardiac biomarkers in patients undergoing elective percutaneous coronary intervention: A randomized controlled clinical trial

BACKGROUND

Myocardial ischemia may recur in a significant subset of patients following percutaneous coronary intervention (PCI). Lycopene, a carotenoid with antioxidant activity, has evidence for beneficial effects on cardiovascular system. In the present study, we aimed to evaluate the possible preventive effect of lycopene against post-PCI myocardial damage by detection of cardiac biomarkers of ischemia.

METHODS

A total of 45 patients who planned to undergo elective PCI were randomly assigned to two groups to receive either lycopene (30 mg 12 hours before PCI as well as 15 mg just before and 8 hours after PCI) along with standard treatment (n = 23) or only standard treatment (n = 22). Standard treatment included aspirin, a statin, and a beta-blocker. The serum levels of creatine kinase-MB (CK-MB), troponin I, and high sensitivity C-reactive protein (hs-CRP) were measured 12 hours before and 12 hours after the procedure and were compared between the two groups.

RESULTS

The use of lycopene significantly prevented the increase of CK-MB following PCI compared to control (P = 0.048). However, it had not any significant effect on serum levels of troponin I (TnI) (P = 0.176) and hs-CRP (P = 0.186) compared to control.

CONCLUSION

Lycopene can prevent the increase of CK-MB following PCI. Therefore, it has the potential for prevention of post-PCI cardiovascular events. However, more studies are needed to confirm such an effect.

MiR-124 Regulates the Inflammation and Apoptosis in Myocardial Infarction Rats by Targeting STAT3

This study aimed to discover the effect of miR-124/STAT3 axis on the inflammation and cell apoptosis in myocardial infarction (MI) rats. Sprague-Dawley (SD) male rats were selected for establishing MI models and divided into Sham, MI, MI + anti-miR-124 and MI + Ad-miR-124 groups. Cardiac function was detected via echocardiography. Hematoxylin & eosin (HE) and triphenyltetrazolium chloride (TTC) staining were used to observe the pathological changes and infarction area, while transferase (TdT)-mediated D-UTP-biotin nick end labeling (TUNEL) assay was to observe myocardial apoptosis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of inflammatory cytokines. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blotting were performed to determine the mRNA and protein levels, respectively. Dual luciferase reporter gene assay revealed that STAT3 was a target gene of miR-124. The expression levels of miR-124 were increased and the pSTAT3/STAT3 ratio was reduced in the MI rats. The rats in the MI group showed enhanced LVEDD and LVESD, reduced LVEF and LVFS, as well as larger myocardial infarction area compared with the Sham group, Besides, IL-1β, IL-6, TNF-α and MCP-1 levels were elevated and the expressions of Bax/Bcl-2 ratio and cleaved caspase-3 were downregulated in MI group. We further found that silencing miR-124 improved cardiac function, reduced infarction area and the levels of inflammatory cytokines, as well as prevented myocardial apoptosis in MI rats. Silencing miR-124 could inhibit the inflammation and apoptosis of myocardial cells, thereby relieving the MI injury via upregulation of STAT3.

The Role of Matrix Metalloproteinase-9 in Atherosclerotic Plaque Instability

Matrix metalloproteinase-9 (MMP-9) belongs to the MMP family and has been widely investigated. Excessive MMP-9 expression can enhance extracellular matrix degradation and promote plaque instability. Studies have demonstrated that MMP-9 levels are higher in vulnerable plaques than in stable plaques. Additionally, several human studies have demonstrated that MMP-9 may be a predictor of atherosclerotic plaque instability and a risk factor for future adverse cardiovascular and cerebrovascular events. MMP-9 deficiency or blocking MMP-9 expression can inhibit plaque inflammation and prevent atherosclerotic plaque instability. All of these results suggest that MMP-9 may be a useful predictive biomarker for vulnerable atherosclerotic plaques, as well as a therapeutic target for preventing atherosclerotic plaque instability. In this review, we describe the structure, function, and regulation of MMP-9. We also discuss the role of MMP-9 in predicting and preventing atherosclerotic plaque instability.

Computational model predicts paracrine and intracellular drivers of fibroblast phenotype after myocardial infarction

The fibroblast is a key mediator of wound healing in the heart and other organs, yet how it integrates multiple time-dependent paracrine signals to control extracellular matrix synthesis has been difficult to study in vivo. Here, we extended a computational model to simulate the dynamics of fibroblast signaling and fibrosis after myocardial infarction (MI) in response to time-dependent data for nine paracrine stimuli. This computational model was validated against dynamic collagen expression and collagen area fraction data from post-infarction rat hearts. The model predicted that while many features of the fibroblast phenotype at inflammatory or maturation phases of healing could be recapitulated by single static paracrine stimuli (interleukin-1 and angiotensin-II, respectively), mimicking the reparative phase required paired stimuli (e.g. TGFβ and endothelin-1). Virtual overexpression screens simulated with either static cytokine pairs or post-MI paracrine dynamic predicted phase-specific regulators of collagen expression. Several regulators increased (Smad3) or decreased (Smad7, protein kinase G) collagen expression specifically in the reparative phase. NADPH oxidase (NOX) overexpression sustained collagen expression from reparative to maturation phases, driven by TGFβ and endothelin positive feedback loops. Interleukin-1 overexpression had mixed effects, both enhancing collagen via the TGFβ positive feedback loop and suppressing collagen via NFκB and BAMBI (BMP and activin membrane-bound inhibitor) incoherent feed-forward loops. These model-based predictions reveal network mechanisms by which the dynamics of paracrine stimuli and interacting signaling pathways drive the progression of fibroblast phenotypes and fibrosis after myocardial infarction.

Protective effects of lycopene in cancer, cardiovascular, and neurodegenerative diseases: An update on epidemiological and mechanistic perspectives

Recent mechanistic and epidemiological studies have provided insights into health benefits of dietary lycopene to decrease the risk and complications associated with several chronic diseases such as cardiovascular diseases (CVD), obesity, type 2 diabetes, cancer, and neurodegenerative disorders. These chronic diseases are primarily associated with oxidative stress-induced systemic and low-grade chronic inflammation. Owing to its potent antioxidant properties, lycopene can potentially alleviate enhanced levels of proinflammatory mediators (e.g., proinflammatory cytokines IL-8, -6, and -1, and oxidized phospholipids) and prevent NF-κB activation by modulating oxidative stress. Moreover, lycopene serves as a precursor for various oxidative cleavage products and metabolites including Apo-8'-, apo-10'-, and apo-12'-lycopenals that can interact with multiple transcription factors (e.g., Nrf2, RARs, RXRs, and PPARs) to overexpress antioxidant and cytoprotective Phase II enzymes and other growth-stimulating proteins (e.g., brain-derived neurotrophic factor (BDNF) for enhanced neuroprotection. These events altogether can protect the body from chronic inflammatory disorders. In the present review, the latest mechanistic development from cell and animal models and results of case-control, cohort, and randomized trials are discussed to support the protective part of lycopene in cancer, CVD, and neurodegenerative disorders. This review focuses on cellular and molecular events involved in protective effects of lycopene. Although molecular and cellular mechanisms involved in health-promoting activities of lycopene have been reported, no detailed mechanistic studies have been published. Hence, future studies should be conducted to elucidate the mechanistic role(s) of lycopene-derived oxidation products in modulating cellular signaling.

Cardioprotective Effects of Nanoemulsions Loaded with Anti-Inflammatory Nutraceuticals against Doxorubicin-Induced Cardiotoxicity

Doxorubicin is a highly active antineoplastic agent, but its clinical use is limited because of its cardiotoxicity. Although nutraceuticals endowed with anti-inflammatory properties exert cardioprotective activity, their bioavailability and stability are inconsistent. In an attempt to address this issue, we evaluated whether bioavailable nanoemulsions loaded with nutraceuticals (curcumin and fresh and dry tomato extracts rich in lycopene) protect cardiomyoblasts (H9C2 cells) from doxorubicin-induced toxicity. Nanoemulsions were produced with a high-pressure homogenizer. H9C2 cells were incubated with nanoemulsions loaded with different nutraceuticals alone or in combination with doxorubicin. Cell viability was evaluated with a modified MTT method. The levels of the lipid peroxidation products malondialdehyde (MDA) and 4-hydroxy-2-butanone (4-HNA), and of the cardiotoxic-related interleukins IL-6, IL-8, IL-1β and IL-10, tumor necrosis factor-alpha (TNF-α), and nitric oxide were analyzed in cardiomyoblasts. The hydrodynamic size of nanoemulsions was around 100 nm. Cell viability enhancement was 35–40% higher in cardiomyoblasts treated with nanoemulsion + doxorubicin than in cardiomyoblasts treated with doxorubicin alone. Nanoemulsions also protected against oxidative stress as witnessed by a reduction of MDA and 4-HNA. Notably, nanoemulsions inhibited the release of IL-6, IL-8, IL-1β, TNF-α and nitric oxide by around 35–40% and increased IL-10 production by 25–27% versus cells not treated with emulsions. Of the nutraceuticals evaluated, lycopene-rich nanoemulsions had the best cardioprotective profile. In conclusion, nanoemulsions loaded with the nutraceuticals described herein protect against cardiotoxicity, by reducing inflammation and lipid oxidative stress. These results set the stage for studies in preclinical models.

Lycopene and Vascular Health

Lycopene is a lipophilic, unsaturated carotenoid, found in red-colored fruits and vegetables, including tomatoes, watermelon, papaya, red grapefruits, and guava. The present work provides an up to date overview of mechanisms linking lycopene in the human diet and vascular changes, considering epidemiological data, clinical studies, and experimental data. Lycopene may improve vascular function and contributes to the primary and secondary prevention of cardiovascular disorders. The main activity profile of lycopene includes antiatherosclerotic, antioxidant, anti-inflammatory, antihypertensive, antiplatelet, anti-apoptotic, and protective endothelial effects, the ability to improve the metabolic profile, and reduce arterial stiffness. In this context, lycopene has been shown in numerous studies to exert a favorable effect in patients with subclinical atherosclerosis, metabolic syndrome, hypertension, peripheral vascular disease, stroke and several other cardiovascular disorders, although the obtained results are sometimes inconsistent, which warrants further studies focusing on its bioactivity.

Effects of neuregulin-1 on autonomic nervous system remodeling post-myocardial infarction in a rat model

Sympathetic nerve and vagus nerve remodeling play an important part in cardiac function post-myocardial infarction (MI). Increasing evidence indicates that neuregulin-1 (NRG-1) improves cardiac function following heart failure. Since its impact on cardiac function and neural remodeling post-MI is poorly understood, we aimed to investigate the role of NRG-1 in autonomic nervous system remodeling post-MI. Forty-five Sprague-Dawley rats were equally randomized into three groups: sham (with the left anterior descending coronary artery exposed but without ligation), MI (left anterior descending coronary artery ligation), and MI plus NRG-1 (left anterior descending coronary artery ligation followed by intraperitoneal injection of NRG-1 (10 μg/kg, once daily for 7 days)). At 4 weeks after MI, echocardiography was used to detect the rat cardiac function by measuring the left ventricular end-systolic inner diameter, left ventricular diastolic diameter, left ventricular end-systolic volume, left ventricular end-diastolic volume, left ventricular ejection fraction, and left ventricular fractional shortening. mRNA and protein expression levels of tyrosine hydroxylase, growth associated protein-43 (neuronal specific protein), nerve growth factor, choline acetyltransferase (vagus nerve marker), and vesicular acetylcholine transporter (cardiac vagal nerve fiber marker) in ischemic myocardia were detected by real-time PCR and western blot assay to assess autonomous nervous remodeling. After MI, the rat cardiac function deteriorated significantly, and it was significantly improved after NRG-1 injection. Compared with the MI group, mRNA and protein levels of tyrosine hydroxylase and growth associated protein-43, as well as choline acetyltransferase mRNA level significantly decreased in the MI plus NRG-1 group, while mRNA and protein levels of nerve growth factor and vesicular acetylcholine transporters, as well as choline acetyltransferase protein level slightly decreased. Our results indicate that NRG-1 can improve cardiac function and regulate sympathetic and vagus nerve remodeling post-MI, thus reaching a new balance of the autonomic nervous system to protect the heart from injury.

High mobility group box 1 protein attenuates myocardial ischemia reperfusion injury via inhibition of the p38 mitogen-activated protein kinase signaling pathway

The present study aimed to determine the effects of high mobility group box 1 protein (HMGB1) on myocardial ischemia reperfusion (I/R) injury in rats following acute myocardial ischemia and investigate the underlying molecular mechanisms of these effects. Male Wistar rats were randomly divided into the following groups (n=10/group): Sham operation; I/R; HMGB50 (50 ng/kg HMGB1 before I/R); HMGB100 (100 ng/kg HMGB1 before I/R); and HMGB200 (200 ng/kg HMGB1 before I/R). Serum cardiac troponin I (cTnI), interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels were subsequently measured. Myocardial levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were also determined. Myocardial infarction size (IS) was determined by 2,3,5-triphenyltetrazolium chloride staining. Myocardial expression of hypoxia inducible factor (HIF)-1α and phosphorylated p38 mitogen-activated protein kinase (P-p38 MAPK) protein was measured using western blotting. The results demonstrated that HMGB1 significantly decreased serum levels of cTnI, IL-6 and TNF-α and myocardial IS in I/R rats compared with the sham group (all P<0.05). HMGB1 also significantly decreased and increased myocardial levels of MDA and SOD, respectively (both P<0.05). HMGB1 significantly increased myocardial expression of HIF-1α and decreased expression of P-p38 MAPK following I/R (both P<0.05). These effects of HMGB1 occurred in a dose-dependent manner. The results of the current study indicate that the cardioprotective effects of intravenous HMGB1 are associated with increased myocardial expression of HIF-1α via inhibition of P-p38 MAPK expression, leading to inhibition of the P-p38 MAPK signaling pathway.

Tomato (Lycopersicon esculentum) or lycopene supplementation attenuates ventricular remodeling after myocardial infarction through different mechanistic pathways

The objective of this study was to evaluate the influence of tomato or lycopene supplementation on cardiac remodeling after myocardial infarction (MI). Male Wistar rats were assigned to four groups: the sham group (animals that underwent simulated surgery) that received a standard chow (S; n=18), the infarcted group that received a standard chow (MI; n=13), the infarcted group supplemented with lycopene (1 mg of lycopene/kg body weight/day) (MIL; n=16) and the infarcted group supplemented with tomato (MIT; n=16). After 3 months, morphological, functional and biochemical analyses were performed. The groups MIL and MIT showed decreased interstitial fibrosis induced by infarction. Tomato supplementation attenuated the hypertrophy induced by MI. In addition, tomato and lycopene improved diastolic dysfunction evaluated by echocardiographic and isolated heart studies, respectively. The MI group showed higher levels of cardiac TNF-α compared to the MIL and MIT groups. Decreased nuclear factor E2-related factor 2 was measured in the MIL group. Lipid hydroperoxide levels were higher in the infarcted groups; however, the MIT group had a lower concentration than did the MI group [S=223±20.8, MI=298±19.5, MIL=277±26.6, MIT=261±28.8 (nmol/g); n=8; P<.001]. We also examined left ventricle miRNA expression; when compared to the S group, the MIL group uniquely down-regulated the expression of eight miRNAs. No miRNA was found to be up-regulated uniquely in the MIT and MIL groups. In conclusion, tomato or lycopene supplementation attenuated the cardiac remodeling process and improved diastolic function after MI. However, the effect of lycopene and tomato supplementation occurred through different mechanistic pathways.

Wnt signaling pathway in cardiac fibrosis: New insights and directions

OBJECTIVE

Wnt signaling pathway significantly participates in cardiac fibrosis and CFs activation. Therefore, we reviewed current evidence on the new perspectives and biological association between Wnt signaling pathway and cardiac fibrosis.

DESIGN AND METHODS

A PubMed database search was performed for studies of Wnt signaling pathway in cardiac fibrosis and CFs activation.

RESULTS

Numerous studies have shown that the Wnt signaling pathway significantly participates in cardiac fibrosis pathogenesis. The aim of this review is to describe the present knowledge about the Wnt signaling pathway significantly participating in cardiac fibrosis and CFs activation, and look ahead on new perspectives of Wnt signaling pathway research. Moreover, we will discuss the different insights that interact with the Wnt signaling pathway-regulated cardiac fibrosis. The Wnt proteins are glycoproteins that bind to the Fz receptors on the cell surface, which lead to several important biological functions, such as cell differentiation and proliferation. There are several signals among the characterized pathways of cardiac fibrosis, including Wnt/β-catenin signaling. In this review, new insight into the Wnt signaling pathway in cardiac fibrosis pathogenesis is discussed, with special emphasis on Wnt/β-catenin.

CONCLUSION

It seems reasonable to suggest the potential targets of Wnt signaling pathway and it can be developed as a therapeutic target for cardiac fibrosis.

Effects of hydrogen sulfide on myocardial fibrosis and PI3K/AKT1-regulated autophagy in diabetic rats

Myocardial fibrosis is the predominant pathological characteristic of diabetic myocardial damage. Previous studies have indicated that hydrogen sulfide (H2S) has beneficial effects in the treatment of various cardiovascular diseases. However, there is little research investigating the effect of H2S on myocardial fibrosis in diabetes. The present study aimed to investigate the effects of H2S on the progression of myocardial fibrosis induced by diabetes. Diabetes was induced in rats by intraperitoneal injection of streptozotocin. Sodium hydrosulfide (NaHS) was used as an exogenous donor of H2S. After 8 weeks, expression levels of cystathionine-γ-lyase were determined by western blot analysis and morphological changes in the myocardium were assessed by hematoxylin and eosin staining and Masson staining. The hydroxyproline content and fibrosis markers were determined by a basic hydrolysis method and western blot analysis, respectively. Autophagosomes were observed under transmission electron microscopy. Expression levels of autophagy-associated proteins and their upstream signaling molecules were also evaluated by western blotting. The results of the current study indicated that diabetes induced marked myocardial fibrosis, enhanced myocardial autophagy and suppressed the phosphatidylinositol-4,5-bisphosphate 3-kinase/RAC-α serine/threonine-protein kinase (PI3K/AKT1) signaling pathway. By contrast, following treatment with NaHS, myocardial fibrosis was ameliorated, myocardial autophagy was decreased and the PI3K/AKT1 pathway suppression was reversed. The results of the present study demonstrated that the protective effect of H2S against diabetes-induced myocardial fibrosis may be associated with the attenuation of autophagy via the upregulation of the PI3K/AKT1 signaling pathway.

Rosuvastatin attenuates atrial structural remodelling in rats with myocardial infarction through the inhibition of the p38 MAPK signalling pathway

OBJECTIVE

The purpose of this study was to verify the hypothesis that rosuvastatin attenuates atrial structural remodelling in rats with myocardial infarction (MI) through the regulation of the p38 mitogen-activated protein kinase (MAPK) signalling pathway.

METHODS

A total of 66 rats were used in this study to establish a model of MI. The 56 rats that survived the first 24h after surgery were randomly divided into four groups: the control group (C group), the rosuvastatin group (R group), the low-dose torasemide group (T1 group), and the high-dose torasemide group (T2 group). The four groups of rats received daily intragastric administration of normal saline, rosuvastatin, or torasemide (T1: 1mg/kg body weight; T2: 2mg/kg body weight) for a total of four weeks. The rats in the sham-operated group (n=14) also received daily intragastric administration of normal saline for four weeks. After four weeks of intervention, the left ventricular end-diastolic pressure (LVEDP) was measured in all groups of rats by haemodynamic methods. The rats were then sacrificed, and the left atrial tissues were collected. The collagen volume fractions (CVFs) in the left atrial tissues were determined using Masson's trichrome staining. The expression of phosphorylated p38 (P-p38) MAPK in the left atrial tissues was examined by immunohistochemistry and western blot analysis.

RESULTS

The results showed that LVEDP, CVF, and P-p38 MAPK expression were drastically elevated in the four MI groups in comparison to the sham-operated group (p<0.001). Rosuvastatin elevated the left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF). Both rosuvastatin and torasemide improved the haemodynamic parameters. No significant difference was detected in LVEDP between the R group and the T1 group (p=0.37). In contrast, LVEDP was significantly higher in the R group than in the T2 group (p <0.05). CVF (%) was markedly decreased in the R group compared to the C, T1, and T2 groups (decreased by 47.4%, 28%, and 20.1%, respectively). Immunohistochemical analysis showed that the indices of P-p38 MAPK positive cells were significantly decreased in the R group in comparison with the C, T1, and T2 groups (decreased by 44.6%, 36.6%, and 21.4%, respectively). Western blot analysis demonstrated that P-p38 MAPK expression was markedly reduced in the R group compared with the C and T1 groups (reduced by 67% and 40.5%, respectively). The level of P-p38 MAPK in the R group was slightly higher than in the T2 group. However, the difference was not statistically significant (p>0.05).

CONCLUSION

Rosuvastatin attenuates atrial structural remodelling in rats with MI. The mechanism underlying this phenomenon may be associated with the downregulation of P-p38 MAPK by rosuvastatin.

Protective effect of saponins extract from Panax japonicus on myocardial infarction: involvement of NF-κB, Sirt1 and mitogen-activated protein kinase signalling pathways and inhibition of inflammation

Objective

Inflammation is widely acknowledged to increase morbidity and mortality in myocardial infarction (MI), and the ideal therapeutic methods should be aimed at the inflammation reaction triggers. The aim was to evaluate the protective effect of saponins extracted from Panax japonicus (SPJ) on MI, and based on these results investigate the possible involvement mechanism of the nuclear factor-kappa B (NF-κB), sirtuin1 (SIRT1) and mitogen-activated protein kinases (MAPKs) signalling pathways.

Methods

Sprague-Dawley rats were randomly divided into sham, MI, MI + SPJ 50 and SPJ 100 mg/kg groups. After administration for 3 days, MI rats were created by ligaturing coronary artery, and then underwent the same administration for 7 days as before. Cardiac function and the expressions of pro-apoptosis protein Bax, anti-apoptosis protein Bcl-2, NF-κB, SIRT1, MAPKs signal pathway-related proteins and inflammatory factor, such as tumour necrosis factor alpha (TNF-α) and monocyte chemoattractant protein 1 (MCP-1), were assessed.

Key findings

SPJ might significantly improve cardiac function, decrease the serum MCP-1 and TNF-α levels, ameliorate the increased Bax protein expression and decrease Bcl-2 protein expression, and suppress the protein expressions of NF-κBp65 subunit, extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 MAPK, but have no effect on c-Jun NH2-terminal kinase, and increase the expression of SIRT1. Histopathological observations provided supportive evidence for aforementioned results, and with the dose of SPJ increasing, the aforesaid improvement became more and more strong.

Conclusion

The studies demonstrated that SPJ exerted beneficially cardioprotective effects on MI rats, mainly inhibiting NF-κB, ERK1/2 and p38 MAPK activation, but increased the expression of SIRT1, alleviating MI injury and cardiac cell death.

Ginsenoside Rb3 protects cardiomyocytes against ischemia-reperfusion injury via the inhibition of JNK-mediated NF-κB pathway: a mouse cardiomyocyte model

Ginsenoside Rb3 is extracted from the plant Panax ginseng and plays important roles in cardiovascular diseases, including myocardial ischemia-reperfusion (I/R) injury. NF-κB is an important transcription factor involved in I/R injury. However, the underlying mechanism of ginsenoside Rb3 in myocardial I/R injury remains poorly understood. In the current study, a model of myocardial I/R injury was induced via oxygen and glucose deprivation (OGD) followed by reperfusion (OGD-Rep) in mouse cardiac myoblast H9c2 cells. Our data demonstrate that ginsenoside Rb3 suppresses OGD-Rep-induced cell apoptosis by the suppression of ROS generation. By detecting the NF-κB signaling pathway, we discover that the protective effect of ginsenoside Rb3 on the OGD-Rep injury is closely related to the inhibition of NF-κB activity. Ginsenoside Rb3 inhibits the upregulation of phospho-IκB-α and nuclear translocation of NF-κB subunit p65 which are induced by ORD-Rep injury. In addition, the extract also inhibits the OGD-Rep-induced increase in the expression of inflammation-related factors, such as IL-6, TNF-α, monocyte chemotactic protein-1 (MCP-1), MMP-2 and MMP-9. However, LPS treatment alleviates the protective roles of ginsenoside Rb3 and activates the NF-κB pathway. Finally, the upstream factors of NF-κB were analyzed, including the Akt/Foxo3a and MAPK signaling pathways. We find that ginsenoside Rb3 pretreatment only decreases the phosphorylation of JNK induced by OGD-Rep injury, an indicator of the MAPK pathway. Importantly, an inhibitor of phospho-JNK, SP600125, protects against OGD-Rep induced apoptosis and inhibited NF-κB signaling pathway, similar to the roles of ginsenoside Rb3. Taken together, our results demonstrate that the protective effect of ginsenoside Rb3 on the OGD-Rep injury is attributed to the inhibition of JNK-mediated NF-κB activation, suggesting that ginsenoside Rb3 has the potential to serve as a novel therapeutic agent for myocardial I/R injury.