Angiotensin-(1-7) prevents T3-induced cardiomyocyte hypertrophy by upregulating FOXO3/SOD1/catalase and downregulating NF-ĸB

Increased macrophages contribute to thyroid hormone-induced cardiac alterations in mice

AIMS

The heart is one of the main targets of thyroid hormone. Patients with hyperthyroidism, a disease with high incidence in the population, have increased arrhythmia risk and cardiac hypertrophy, which is an independent predictor of adverse cardiovascular outcomes. Recent research has revealed the essential roles of leukocytes in cardiac homeostasis and stress-induced responses. Here, we aimed to evaluate the role of immune cells in cardiac changes induced by elevated triiodothyronine (T3) levels.

METHODS

The hyperthyroid condition in mice was mimicked by daily injections (i.p.) of T3 (14 μg/100 g BW) for 7 or 14 days.

RESULTS

Increased heart rate and cardiac mass observed after 7 days of T3 treatment was associated with enhanced myocardial population of neutrophils, dendritic cells, and inflammatory phenotypes of monocytes and macrophages, without circulating changes in these cells, as evaluated by flow cytometry. In vitro experiments demonstrated bias toward pro-inflammatory polarization in isolated bone marrow-derived macrophages (BMDM) in response to T3. Interestingly, depletion of macrophages in mice prevented hypertrophic heart growth, tachycardia, and increased gene expression of the pro-inflammatory cytokine interleukin-(IL)-6 caused by hyperthyroid condition.

CONCLUSION

Together, these new findings indicate the involvement of macrophages in the cardiac changes promoted by higher T3 levels. Considering that sustained cardiac growth and tachycardia can potentially lead to heart failure, our results suggest that targeting macrophages might be a novel therapeutic approach for attenuating cardiac disorders caused by hyperthyroidism.

Distinct effects of physical and functional ablation of brown adipose tissue on T3-dependent pathological cardiac remodeling

Heart failure tends to deteriorate in colder climates, heightening the risk of major adverse cardiovascular events. Brown adipose tissue (BAT) serves as both a thermogenic organ and an atypical site for triiodothyronine (T3) synthesis in response to cold. This study investigates the potential role of BAT in contributing to abdominal aortic constriction (AAC)-induced pathological cardiac remodeling during cold exposure. In this study, we developed a mouse model of pathological cardiac remodeling using AAC. Physical excision of interscapular BAT (iBATx) was performed during cold exposure, and T3 synthesis levels were measured. Additionally, the impact of uncoupling protein 1 (UCP1) knockout on thermogenic function and pathological cardiac remodeling was investigated. In vitro studies were conducted to assess the effect of T3 on cardiomyocyte hypertrophy induced by phenylephrine (PE). Physical removal of interscapular BAT during cold exposure decreased T3 synthesis and mitigated pathological cardiac remodeling. Conversely, UCP1 knockout eliminated thermogenic function during cold exposure, while preserving BAT integrity increased T3 synthesis and exacerbated pathological cardiac remodeling. In vitro, T3 further aggravated cardiomyocyte hypertrophy caused by PE. These findings underscore the distinct effects of physical and functional BAT ablation on pathological cardiac remodeling, primarily through altering T3 levels rather than thermogenesis in cold environments. This research provides new insights into the differential roles of BAT in cardiac health, particularly under cold exposure conditions.

The mechanism of 14-3-3η in thyroxine induced mitophagy in cardiomyocytes

Hyperthyroidism is becoming increasingly important as an independent risk factor for cardiovascular disease, eventually resulting in cardiac hypertrophy and heart failure. The 14-3-3 protein family subtypes regulate many cellular processes in eukaryotes by interacting with a diverse array of client proteins. Considering that the 14-3-3η protein protects cardiomyocytes by affecting mitochondrial function, exploring the biological influence and molecular mechanisms by which 14-3-3η alleviates the cardiac hypertrophy of hyperthyroidism is imperative. In vivo and in vitro, RT-PCR, Western blot, and Mitochondrial tracking assay were performed to understand the molecular mechanism of thyroxine-induced cardiomyocyte hypertrophy. HE staining, transmission electron microscopy, and immunofluorescence were used to observe intuitively changes of hearts and cardiomyocytes. The in vivo and in vitro results indicated that overexpression of the 14-3-3η ameliorated thyroxine-induced cardiomyocyte hypertrophy, whereas knockdown of the 14-3-3η protein aggravated thyroxine-induced cardiomyocyte hypertrophy. Additionally, overexpression of the 14-3-3η protein reduces thyroxine-induced mitochondrial damage and mitophagy in cardiomyocytes. Overexpression of 14-3-3η protein improves excessive mitophagy in the myocardium caused by thyroxine and thus prevents cardiac hypertrophy.

EEPD1 attenuates radiation-induced cardiac hypertrophy and apoptosis by degrading FOXO3A in cardiomyocytes

Radiation-induced heart disease (RIHD) is a severe delayed complication of thoracic irradiation (IR). Endonuclease/exonuclease/phosphatase family domain-containing 1 ( EEPD1) plays an important role in DNA damage repair, but its role in RIHD is less known. In this study, EEPD1 global knockout mice, C57BL/6J mice, and C57BL/6J mice overexpressing EEPD1 are treated with radiation at a total dose of 20 Gy or 0 Gy. After 9 weeks, echocardiography is used to assess cardiac hypertrophy and apoptosis. The results show that EEPD1 deletion exacerbates radiation-induced cardiac hypertrophy and apoptosis, while EEPD1 overexpression has the opposite effect. Further mechanistic investigations reveal that EEPD1 interacts with FOXO3A and destabilizes it by catalyzing its deubiquitination. Inhibition of FOXO3A ameliorates cardiac hypertrophy and apoptosis after EEPD1 knockdown. Thus, EEPD1 protects against radiation-induced cardiac hypertrophy and apoptosis via destabilization of FOXO3A, which may offer new insight into therapeutic strategies for RIHD.

Angiotensin 1-7 increases cardiac tolerance to ischemia/reperfusion and mitigates adverse remodeling of the heart-The signaling mechanism

BACKGROUND

The high mortality rate of patients with acute myocardial infarction (AMI) remains the most pressing issue of modern cardiology. Over the past 10 years, there has been no significant reduction in mortality among patients with AMI. It is quite obvious that there is an urgent need to develop fundamentally new drugs for the treatment of AMI. Angiotensin 1-7 has some promise in this regard.

OBJECTIVE

The objective of this article is analysis of published data on the cardioprotective properties of angiotensin 1-7.

METHODS

PubMed, Scopus, Science Direct, and Google Scholar were used to search articles for this study.

RESULTS

Angiotensin 1-7 increases cardiac tolerance to ischemia/reperfusion and mitigates adverse remodeling of the heart. Angiotensin 1-7 can prevent not only ischemic but also reperfusion cardiac injury. The activation of the Mas receptor plays a key role in these effects of angiotensin 1-7. Angiotensin 1-7 alleviates Ca2+ overload of cardiomyocytes and reactive oxygen species production in ischemia/reperfusion (I/R) of the myocardium. It is possible that both effects are involved in angiotensin 1-7-triggered cardiac tolerance to I/R. Furthermore, angiotensin 1-7 inhibits apoptosis of cardiomyocytes and stimulates autophagy of cells. There is also indirect evidence suggesting that angiotensin 1-7 inhibits ferroptosis in cardiomyocytes. Moreover, angiotensin 1-7 possesses anti-inflammatory properties, possibly achieved through NF-kB activity inhibition. Phosphoinositide 3-kinase, Akt, and NO synthase are involved in the infarct-reducing effect of angiotensin 1-7. However, the specific end-effector of the cardioprotective impact of angiotensin 1-7 remains unknown.

CONCLUSION

The molecular nature of the end-effector of the infarct-limiting effect of angiotensin 1-7 has not been elucidated. Perhaps, this end-effector is the sarcolemmal KATP channel or the mitochondrial KATP channel.

Dronedarone Attenuates Ang II-Induced Myocardial Hypertrophy Through Regulating SIRT1/FOXO3/PKIA Axis

BACKGROUND AND OBJECTIVES

Long-term pathological myocardial hypertrophy (MH) seriously affects the normal function of the heart. Dronedarone was reported to attenuate left ventricular hypertrophy of mice. However, the molecular regulatory mechanism of dronedarone in MH is unclear.

METHODS

Angiotensin II (Ang II) was used to induce cell hypertrophy of H9C2 cells. Transverse aortic constriction (TAC) surgery was performed to establish a rat model of MH. Cell size was evaluated using crystal violet staining and rhodamine phalloidin staining. Reverse transcription quantitative polymerase chain reaction and western blot were performed to detect the mRNA and protein expressions of genes. JASPAR and luciferase activity were conducted to predict and validate interaction between forkhead box O3 (FOXO3) and protein kinase inhibitor alpha (PKIA) promoter.

RESULTS

Ang II treatment induced cell hypertrophy and inhibited sirtuin 1 (SIRT1) expression, which were reversed by dronedarone. SIRT1 overexpression or PKIA overexpression enhanced dronedarone-mediated suppression of cell hypertrophy in Ang II-induced H9C2 cells. Mechanistically, SIRT1 elevated FOXO3 expression through SIRT1-mediated deacetylation of FOXO3 and FOXO3 upregulated PKIA expression through interacting with PKIA promoter. Moreover, SIRT1 silencing compromised dronedarone-mediated suppression of cell hypertrophy, while PKIA upregulation abolished the influences of SIRT1 silencing. More importantly, dronedarone improved TAC surgery-induced MH and impairment of cardiac function of rats via affecting SIRT1/FOXO3/PKIA axis.

CONCLUSIONS

Dronedarone alleviated MH through mediating SIRT1/FOXO3/PKIA axis, which provide more evidences for dronedarone against MH.

Breviscapine protects against pathological cardiac hypertrophy by targeting FOXO3a-mitofusin-1 mediated mitochondrial fusion

Forkhead box O3a (FOXO3a)-mediated mitochondrial dysfunction plays a pivotal effect on cardiac hypertrophy and heart failure (HF). However, the role and underlying mechanisms of FOXO3a, regulated by breviscapine (BRE), on mitochondrial function in HF therapy remain unclear. This study reveals that BRE-induced nuclear translocation of FOXO3a facilitates mitofusin-1 (MFN-1)-dependent mitochondrial fusion in cardiac hypertrophy and HF. BRE effectively promotes cardiac function and ameliorates cardiac remodeling in pressure overload-induced mice. In addition, BRE mitigates phenylephrine (PE)-induced cardiac hypertrophy in cardiomyocytes and fibrosis remodeling in fibroblasts by inhibiting ROS production and promoting mitochondrial fusion, respectively. Transcriptomics analysis underscores the close association between the FOXO pathway and the protective effect of BRE against HF, with FOXO3a emerging as a potential target of BRE. BRE potentiates the nuclear translocation of FOXO3a by attenuating its phosphorylation, other than its acetylation in cardiac hypertrophy. Mechanistically, over-expression of FOXO3a significantly inhibits cardiac hypertrophy and mitochondrial injury by promoting MFN-1-mediated mitochondrial fusion. Furthermore, BRE demonstrates its ability to substantially curb cardiac hypertrophy, reduce mitochondrial ROS production, and enhance MFN-1-mediated mitochondrial fusion through a FOXO3a-dependent mechanism. In conclusion, nuclear FOXO3a translocation induced by BRE presents a successful therapeutic avenue for addressing cardiac hypertrophy and HF through promoting MFN-1-dependent mitochondrial fusion.

Effect of diminazene on cardiac hypertrophy through mitophagy in rat models with hyperthyroidism induced by levothyroxine

Hyperthyroidism is associated with the alteration in molecular pathways involved in the regulation of mitochondrial mass and apoptosis, which contribute to the development of cardiac hypertrophy. Diminazene (DIZE) is an animal anti-infection drug that has shown promising effects on improving cardiovascular disease. The aim of the present study was to investigate the therapeutic effect of DIZE on cardiac hypertrophy and the signaling pathways involved in this process in the hyperthyroid rat model. Twenty male Wistar rats were equally divided into four groups: control, hyperthyroid, DIZE, and hyperthyroid + DIZE. After 28 days of treatment, serum thyroxine (T4) and thyroid stimulating hormone (TSH) level, cardiac hypertrophy indices, cardiac damage markers, cardiac malondialdehyde (MDA), and superoxide dismutase (SOD) level, the mRNA expression level of mitochondrial and apoptotic genes were evaluated. Hyperthyroidism significantly decreased the cardiac expression level of SIRT1/PGC1α and its downstream involved in the regulation of mitochondrial biogenesis, mitophagy, and antioxidant enzyme activities including TFAM, PINK1/MFN2, Drp1, and Nrf2, respectively, as well as stimulated mitochondrial-dependent apoptosis by reducing Bcl-2 expression and increasing Bax expression. Treatment with DIZE significantly reversed the downregulation of SIRT1, PGC1α, PINK1, MFN2, Drp1, and Nrf2 but did not significantly change the TFAM expression. Moreover, DIZE suppressed apoptosis by normalizing the cardiac expression levels of Bax and Bcl-2. DIZE is effective in attenuating hyperthyroidism-induced cardiac hypertrophy by modulating the mitophagy-related pathway, suppressing apoptosis and oxidative stress.

Mycn ameliorates cardiac hypertrophy-induced heart failure in mice by mediating the USP2/JUP/Akt/β-catenin cascade

BACKGROUND

Pathological cardiac hypertrophy is associated with cardiac dysfunction and is a key risk factor for heart failure and even sudden death. This study investigates the function of Mycn in cardiac hypertrophy and explores the interacting molecules.

METHODS

A mouse model of cardiac hypertrophy was induced by isoproterenol (ISO). The cardiac dysfunction was assessed by the heart weight-to-body weight ratio (HW/BW), echocardiography assessment, pathological staining, biomarker detection, and cell apoptosis. Transcriptome alteration in cardiac hypertrophy was analyzed by bioinformatics analysis. Gain- or loss-of-function studies of MYCN proto-oncogene (Mycn), ubiquitin specific peptidase 2 (USP2), and junction plakoglobin (JUP) were performed. The biological functions of Mycn were further examined in ISO-treated cardiomyocytes. The molecular interactions were verified by luciferase assay or immunoprecipitation assays.

RESULTS

Mycn was poorly expressed in ISO-treated mice, and its upregulation reduced HW/BW, cell surface area, oxidative stress, and inflammation while improving cardiac function of mice. It also reduced apoptosis of cardiomyocytes in mice and those in vitro induced by ISO. Mycn bound to the USP2 promoter to activate its transcription. USP2 overexpression exerted similar myocardial protective functions. It stabilized JUP protein by deubiquitination modification, which blocked the Akt/β-catenin pathway. Knockdown of JUP restored phosphorylation of Akt and β-catenin protein level, which negated the protective effects of USP2.

CONCLUSION

This study demonstrates that Mycn activates USP2 transcription, which mediates ubiquitination and protein stabilization of JUP, thus inactivating the Akt/β-catenin axis and alleviating cardiac hypertrophy-induced heart failure.

Novel Strategies to Improve the Cardioprotective Effects of Cardioplegia

The use of cardioprotective strategies as adjuvants of cardioplegic solutions has become an ideal alternative for the improvement of post-surgery heart recovery. The choice of the optimal cardioplegia, as well as its distribution mechanism, remains controversial in the field of cardiovascular surgery. There is still a need to search for new and better cardioprotective methods during cardioplegic procedures. New techniques for the management of cardiovascular complications during cardioplegia have evolved with new alternatives and additives, and each new strategy provides a tool to neutralize the damage after ischemia/reperfusion events. Researchers and clinicians have committed themselves to studying the effect of new strategies and adjuvant components with the potential to improve the cardioprotective effect of cardioplegic solutions in preventing myocardial ischemia/reperfusion-induced injury during cardiac surgery. The aim of this review is to explore the different types of cardioplegia, their protection mechanisms, and which strategies have been proposed to enhance the function of these solutions in hearts exposed to cardiovascular pathologies that require surgical alternatives for their corrective progression.

Microglial inflammatory reactions regulated by oxidative stress

Microglia are immune cells in the brain that can respond to endogenous and exogenous substrates to elicit inflammatory reactions. The transcription factor nuclear factor kappa-light-chain-enhancer of activated B induces proinflammatory gene expression in response to foreign matter via pattern recognition receptors; thus, nuclear factor kappa-light-chain-enhancer of activated B is a master regulator of inflammation. During the inflammatory process, very large amounts of reactive oxygen species are generated and promote the onset and progression of inflammation. Interestingly, nuclear factor kappa-light-chain-enhancer of activated B drives the transcription of superoxide dismutase 2 in many types of cells, including microglia. Superoxide dismutase 2 is an antioxidative enzyme that catalyzes the dismutation of superoxide anions into molecular oxygen and hydrogen peroxide. Of note, nuclear factor kappa-light-chain-enhancer of activated B can initiate inflammation to elicit proinflammatory gene expression, while its transcription product superoxide dismutase 2 can suppress inflammation. In this review, we use recent knowledge to describe the interaction between oxidative stress and nuclear factor kappa-light-chain-enhancer of activated B and discuss the complicated role of microglial superoxide dismutase 2 in inflammation.

miRNA-143-3p-Sox6-Myh7 pathway is altered in obesogenic diet-induced cardiac hypertrophy

NEW FINDINGS

What is the central question of this study? To investigate the effect of an obesogenic diet on the expression of microRNAs (miRNAs) involved in cardiac hypertrophy in female mice. What is the main finding and its importance? Female mice fed an obesogenic diet exhibited cardiac hypertrophy associated with increased levels of miRNA-143-3p, decreased levels of Sox6 and increased expression of Myh7. Inhibition of miRNA-143-3p increased Sox6 mRNA levels and reduced Myh7 expression in cardiomyocytes, and prevented angiotensin II-induced cardiomyocyte hypertrophy. Our results indicate that the miRNA-143-3p-Sox6-Myh7 pathway may play a key role in obesity-induced cardiac hypertrophy.

ABSTRACT

Obesity induces cardiometabolic disorders associated with a high risk of mortality. We have previously shown that the microRNA (miRNA) expression profile is changed in obesity-induced cardiac hypertrophy in male mice. Here, we investigated the effect of an obesogenic diet on the expression of microRNAs (miRNAs) involved in cardiac hypertrophy in female mice. Female mice fed an obesogenic diet displayed an increased body weight gain, glucose intolerance, insulin resistance, and dyslipidemia. In addition, obese female mice exhibited cardiac hypertrophy associated with increased levels of several miRNAs, including miR-143-3p. Bioinformatic analysis identified Sox6, a regulator of Myh7 transcription, as a predicted target of the miR-143-3p. Female mice fed an obesogenic diet exhibited decreased levels of Sox6 and increased expression of Myh7 in the heart. Loss-of-function studies in cardiomyocytes revealed that inhibition of miR-143-3p increased Sox6 mRNA levels and reduced Myh7 expression. Collectively, our results indicate that obesity-associated cardiac hypertrophy in female mice is accompanied by alterations in diverse miRNAs, and suggest that the miR-143-3p-Sox6-Myh7 pathway may play a key role in obesity-induced cardiac hypertrophy. This article is protected by copyright. All rights reserved.

Investigation of the Potential Key Genes and the Multitarget Mechanisms of Polygonum cuspidatum against Heart Failure Based on Network Pharmacology and Experimental Validation

In this study, systematic pharmacology and bioinformatic approaches were employed to identify the potential targets of Polygonum cuspidatum (PC) for treating heart failure (HF). The active ingredients of PC were screened by using the TCMSP database, and HF-related genes were identified in the GEO database. Then, the herb-HF targeted-gene networks were constructed using Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analyses were performed to obtain the enriched molecular pathways associated with the pathogenesis of HF. Finally, in vitro experiment was performed to evidence network pharmacology analysis. 170 intersection genes were obtained, and key genes (FOXO3, NFKB1, and TNF) were identified. Besides, GO and KEGG findings indicated that PC treatment of HF was achieved via regulating apoptosis, IL-17 signaling pathway, TNF signaling pathway, response to oxidative stress, and response to reactive oxygen species. And cell experiment revealed that PC could decrease the expression of NFKB1 and TNF and increase the expression of FOXO3, SOD1, and GPX1 in H9C2 cells. These findings showed that the therapeutic mechanism of PC in the treatment of HF may be associated with the regulation of inflammation-related and oxidative stress-related genes.

Anti-Apoptosis and Autophagy Effects of Melatonin Protect Rat Chondrocytes against Oxidative Stress via Regulation of AMPK/Foxo3 Pathways

OBJECTIVE

Emerging evidence has indicated that excessive reactive oxygen species (ROS) have detrimental effects on osteoarthritis (OA). This study aimed to elucidate the effects of melatonin (MT), an antioxidant indolamine secreted from the pineal gland, on chondrocyte senescence and cartilage degeneration, thereby clarifying the underlying mechanisms of ROS-induced OA pathogenesis.

DESIGN

Hydrogen peroxide (H₂O₂) was used to induce oxidative stress in rat chondrocytes. ROS levels were evaluated using cytometry and immunofluorescence. Cell viability was detected using the Cell Counting Kit-8 (CCK-8) assay. Western blotting and qPCR (Quantiative Real-Time Polymerase Chain Reaction) were used to examine apoptosis and autophagy. For in vivo experiments, male Sprague-Dawley rats were randomly divided into a sham-operated group, DMM (destabilization of the medial meniscus) surgery group, and surgery groups that received melatonin. Knee joints were collected and stained for histological analysis.

RESULTS

The data demonstrated that melatonin treatment significantly suppressed H₂O₂-induced matrix degradation and apoptosis, and maintained mitochondrial redox homeostasis. In addition, an enhancement of autophagic flux was observed through western blotting. These findings corresponded with activation of the AMPK/Foxo3 signaling pathways upon melatonin treatment. Histological staining and transmission electron microscopy (TEM) micrographs also demonstrated that melatonin alleviated cartilage ossification and chondrocyte hypertrophy in vivo.

CONCLUSIONS

Our results indicated that melatonin protected chondrocytes via mitochondrial redox homeostasis and autophagy. The effects of melatonin on senescence may apply to other age-related diseases. Thus, melatonin may have multiple potential therapeutic applications.