Fasudil alleviates pressure overload-induced heart failure by activating Nrf2-mediated antioxidant responses

Cardioprotective effects of asiaticoside against diabetic cardiomyopathy: Activation of the AMPK/Nrf2 pathway

Diabetic cardiomyopathy (DCM) is a chronic microvascular complication of diabetes that is generally defined as ventricular dysfunction occurring in patients with diabetes and unrelated to known causes. Several mechanisms have been proposed to contribute to the occurrence and persistence of DCM, in which oxidative stress and autophagy play a non-negligible role. Diabetic cardiomyopathy is involved in a variety of physiological and pathological processes. The 5' adenosine monophosphate-activated protein kinase/nuclear factor-erythroid 2-related factor 2 (AMPK/Nrf2) are expressed in the heart, and studies have shown that asiaticoside (ASI) and activated AMPK/Nrf2 have a protective effect on the myocardium. However, the roles of ASI and AMPK/Nrf2 in DCM are unknown. The intraperitoneal injection of streptozotocin (STZ) and high-fat feed were used to establish the DCM models in 100 C57/BL mice. Asiaticoside and inhibitors of AMPK/Nrf2 were used for intervention. Cardiac function, oxidative stress, and autophagy were measured in mice. DCM mice displayed increased levels of oxidative stress while autophagy levels declined. In addition, AMPK/Nrf2 was activated in DCM mice with ASI intervention. Further, we discovered that AMPK/Nrf2 inhibition blocked the protective effect of ASI by compound C and treatment with ML-385. The present study demonstrates that ASI exerts a protective effect against DCM via the potential activation of the AMPK/Nrf2 pathway. Asiaticoside is a potential therapeutic target for DCM.

Unleashing the Potential of Nrf2: A Novel Therapeutic Target for Pulmonary Vascular Remodeling

Pulmonary vascular remodeling, characterized by the thickening of all three layers of the blood vessel wall, plays a central role in the pathogenesis of pulmonary hypertension (PH). Despite the approval of several drugs for PH treatment, their long-term therapeutic effect remains unsatisfactory, as they mainly focus on vasodilation rather than addressing vascular remodeling. Therefore, there is an urgent need for novel therapeutic targets in the treatment of PH. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a vital transcription factor that regulates endogenous antioxidant defense and emerges as a novel regulator of pulmonary vascular remodeling. Growing evidence has suggested an involvement of Nrf2 and its downstream transcriptional target in the process of pulmonary vascular remodeling. Pharmacologically targeting Nrf2 has demonstrated beneficial effects in various diseases, and several Nrf2 inducers are currently undergoing clinical trials. However, the exact potential and mechanism of Nrf2 as a therapeutic target in PH remain unknown. Thus, this review article aims to comprehensively explore the role and mechanism of Nrf2 in pulmonary vascular remodeling associated with PH. Additionally, we provide a summary of Nrf2 inducers that have shown therapeutic potential in addressing the underlying vascular remodeling processes in PH. Although Nrf2-related therapies hold great promise, further research is necessary before their clinical implementation can be fully realized.

EP1 activation inhibits doxorubicin-cardiomyocyte ferroptosis via Nrf2

Chemotherapeutic agents, such as doxorubicin (DOX), may cause cardiomyopathy, even life-threatening arrhythmias in cancer patients. Ferroptosis-an iron-dependent oxidative form of programmed necrosis, plays a pivotal role in DOX-induced cardiomyopathy (DIC). Prostaglandins (PGs) are bioactive signaling molecules that profoundly modulate cardiac performance in both physiologic and pathologic conditions. Here, we found that PGE2 production and its E-prostanoid 1 receptor (EP1) expression were upregulated in erastin (a ferroptosis inducer) or DOX-treated cardiomyocytes. EP1 inhibition markedly aggravated erastin or DOX-induced cardiomyocyte ferroptosis, whereas EP1 activation exerted opposite effect. Genetic depletion of EP1 in cardiomyocytes worsens DOX-induced cardiac injury in mice, which was efficiently rescued by the ferroptosis inhibitor Ferrostatin-1 (Fer-1). Mechanistically, EP1 activation protected cardiomyocytes from DOX-induced ferroptosis by promoting nuclear factor erythroid 2-related factor 2 (Nrf2)-driven anti-oxidative gene expression, such as glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11). EP1 was coupled with Gαq to elicit intracellular Ca2+ flux and activate the PKC/Nrf2 cascade in ferroptotic cardiomyocytes. EP1 activation also prevents DOX-induced ferroptosis in human cardiomyocytes. Thus, PGE2/EP1 axis protects cardiomyocytes from DOX-induced ferroptosis by activating PKC/Nrf2 signaling and activation of EP1 may represent an attractive strategy for DIC prevention and treatment.

Pharmacologic Activation of Angiotensin-Converting Enzyme II Alleviates Diabetic Cardiomyopathy in db/db Mice by Reducing Reactive Oxidative Stress

BACKGRUOUND

Diabetes mellitus is one of the most common chronic diseases worldwide, and cardiovascular disease is the leading cause of morbidity and mortality in diabetic patients. Diabetic cardiomyopathy (DCM) is a phenomenon characterized by a deterioration in cardiac function and structure, independent of vascular complications. Among many possible causes, the renin-angiotensin-aldosterone system and angiotensin II have been proposed as major drivers of DCM development. In the current study, we aimed to investigate the effects of pharmacological activation of angiotensin-converting enzyme 2 (ACE2) on DCM.

METHODS

The ACE2 activator diminazene aceturate (DIZE) was administered intraperitoneally to male db/db mice (8 weeks old) for 8 weeks. Transthoracic echocardiography was used to assess cardiac mass and function in mice. Cardiac structure and fibrotic changes were examined using histology and immunohistochemistry. Gene and protein expression levels were examined using quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. Additionally, RNA sequencing was performed to investigate the underlying mechanisms of the effects of DIZE and identify novel potential therapeutic targets for DCM.

RESULTS

Echocardiography revealed that in DCM, the administration of DIZE significantly improved cardiac function as well as reduced cardiac hypertrophy and fibrosis. Transcriptome analysis revealed that DIZE treatment suppresses oxidative stress and several pathways related to cardiac hypertrophy.

CONCLUSION

DIZE prevented the diabetes mellitus-mediated structural and functional deterioration of mouse hearts. Our findings suggest that the pharmacological activation of ACE2 could be a novel treatment strategy for DCM.

Coumarin-derived imino sulfonate 5h ameliorates cardiac injury induced by myocardial infarction via activating the Sirt1/Nrf2 signaling pathway

Myocardial infarction (MI) is irreversible damage caused by ischemia and hypoxia in coronary arteries accompanied by elevated catecholamine levels, leading to the accumulation of free radicals. Our previous study discovered coumarin-derived imino sulfonates as a novel class of potential cardioprotective agents possessing strong anti-oxidative effects in cardiomyocytes. Therefore, identifying the compound with the highest cardioprotective activity, 5h, and the mechanism involved was necessary. As a kind of catecholamine, isoproterenol can clinically induce myocardial infarction injury similar to the symptoms of myocardial infarction patients. Our experiments explored the underlying mechanism of this effect of compound 5h by assessing cardiac function, infarct size, histopathological changes, and downregulation of Sirt1 by transfection of adenovirus in vitro and by administering Ex527, a specific inhibitor of Sirt1, in vivo. Compound 5h exhibited strong cardioprotective actions in vivo and in vitro via improving cell survival and cardiac function and decreasing the cellular oxidative stress and cardiac infarct size against MI. Furthermore, compound 5h significantly enhanced cardiac expression of Sirt1, subsequently activating the Nrf2/NQO1 signaling pathway. However, adenovirus-induced Sirt1 downregulation or Sirt1-specific inhibitor largely blocked such beneficial effects of 5h in vitro and in vivo, respectively. Taken together, our results demonstrated, for the first time, that the cardioprotective action of 5h against MI was mediated by reducing oxidative stress and apoptosis through the Sirt1/Nrf2 signaling pathway. Our findings proposed novel insights in developing and evaluating coumarin-derived imino sulfonate compounds as epigenetics-targeted drug therapy for MI.

KRIT1: A Traffic Warden at the Busy Crossroads Between Redox Signaling and the Pathogenesis of Cerebral Cavernous Malformation Disease

Significance: KRIT1 (Krev interaction trapped 1) is a scaffolding protein that plays a critical role in vascular morphogenesis and homeostasis. Its loss-of-function has been unequivocally associated with the pathogenesis of Cerebral Cavernous Malformation (CCM), a major cerebrovascular disease of genetic origin characterized by defective endothelial cell-cell adhesion and ensuing structural alterations and hyperpermeability in brain capillaries. KRIT1 contributes to the maintenance of endothelial barrier function by stabilizing the integrity of adherens junctions and inhibiting the formation of actin stress fibers. Recent Advances: Among the multiple regulatory mechanisms proposed so far, significant evidence accumulated over the past decade has clearly shown that the role of KRIT1 in the stability of endothelial barriers, including the blood-brain barrier, is largely based on its involvement in the complex machinery governing cellular redox homeostasis and responses to oxidative stress and inflammation. KRIT1 loss-of-function has, indeed, been demonstrated to cause an impairment of major redox-sensitive mechanisms involved in spatiotemporal regulation of cell adhesion and signaling, which ultimately leads to decreased cell-cell junction stability and enhanced sensitivity to oxidative stress and inflammation. Critical Issues: This review explores the redox mechanisms that influence endothelial cell adhesion and barrier function, focusing on the role of KRIT1 in such mechanisms. We propose that this supports a novel model wherein redox signaling forms the common link between the various pathogenetic mechanisms and therapeutic approaches hitherto associated with CCM disease. Future Directions: A comprehensive characterization of the role of KRIT1 in redox control of endothelial barrier physiology and defense against oxy-inflammatory insults will provide valuable insights into the development of precision medicine strategies. Antioxid. Redox Signal. 38, 496-528.

Fasudil Ameliorates Methotrexate-Induced Hepatotoxicity by Modulation of Redox-Sensitive Signals

Methotrexate (MTX) is one of the most widely used cytotoxic chemotherapeutic agents, and it is used in the treatment of different autoimmune disorders. However, the clinical applications of MTX are limited by its hepatic toxicity. Hence, the present study was conducted to evaluate the efficacy of fasudil (Rho-Kinase inhibitor) in the amelioration of MTX hepatotoxicity and the possible underlying mechanisms. Experimentally, 32 male Sprague Dawley rats were used and divided into four groups: control, MTX (20 mg/kg, i.p., single dose), fasudil (10 mg/kg/day i.p.) for one week, and fasudil plus MTX. It was found that MTX significantly induced hepatitis and hepatocellular damage, as shown by abnormal histological findings and liver dysfunction (ALT and AST), with up-regulation of the inflammatory mediators NF-κB-p65 and IL-1β. Moreover, MTX remarkably disrupted oxidant/antioxidant status, as evidenced by malondialdehyde (MDA) up-regulation associated with the depletion of superoxide dismutase (SOD), catalase, and reduced glutathione (GSH) levels. Moreover, MTX reduced the hepatic expression of B-cell lymphoma 2 (Bcl-2). On the contrary, the i.p. administration of fasudil significantly ameliorated MTX hepatotoxicity by histopathological improvement, restoring oxidant/antioxidant balance, preventing hepatic inflammation, and improving the hepatic anti-apoptotic capability. Furthermore, fasudil hepatic concentration was determined for the first time using the validated RP-HPLC method. In conclusion, the present study revealed that fasudil has a reliable hepatoprotective effect against MTX hepatotoxicity with underlying antioxidant, anti-inflammatory, and anti-apoptotic mechanisms. It also introduced a new method for the determination of fasudil hepatic tissue concentration using the RP-HPLC technique.

Rho-kinase inhibition ameliorates non-alcoholic fatty liver disease in type 2 diabetic rats

Non-alcoholic fatty liver disease (NAFLD) is linked to type 2 diabetes mellitus (T2DM), obesity, and insulin resistance. The Rho/ROCK pathway had been involved in the pathophysiology of diabetic complications. This study was designed to assess the possible protective impacts of the Rho/Rho-associated coiled-coil containing protein kinase (Rho/ROCK) inhibitor fasudil against NAFLD in T2DM rats trying to elucidate the underlying mechanisms. Animals were assigned into control rats, non-treated diabetic rats with NAFLD, and diabetic rats with NAFLD that received fasudil treatment (10 mg/kg per day) for 6 weeks. The anthropometric measures and biochemical analyses were performed to assess metabolic and liver function changes. The inflammatory and oxidative stress markers and the histopathology of rat liver tissues were also investigated. Groups with T2DM showed increased body weight, serum glucose, and insulin resistance. They exhibited disturbed lipid profile, enhancement of inflammatory cytokines, and deterioration of liver function. Fasudil administration reduced body weight, insulin resistance, and raised liver enzymes. It improved the disturbed lipid profile and attenuated liver inflammation. Moreover, it slowed down the progression of high fat diet (HFD)-induced liver injury and reduced the caspase-3 expression. The present study demonstrated beneficial amelioration effect of fasudil on NAFLD in T2DM. The mechanisms underlying these impacts are improving dyslipidemia, attenuating oxidative stress, downregulated inflammation, improving mitochondrial architecture, and inhibiting apoptosis.

Up-regulation of Nrf2/HO-1 and inhibition of TGF-β1/Smad2/3 signaling axis by daphnetin alleviates transverse aortic constriction-induced cardiac remodeling in mice

Oxidative damage and accumulation of extracellular matrix (ECM) components play a crucial role in the adverse outcome of cardiac hypertrophy. Evidence suggests that nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) can modulate oxidative damage and adverse myocardial remodeling. Daphnetin (Daph) is a coumarin obtained from the plant genus Daphne species that exerts anti-oxidative and anti-inflammatory properties. Herein, we investigated the roles of Daph in transverse aortic constriction (TAC)-induced cardiac hypertrophy and fibrosis in mice. TAC-induced alterations in cardiac hypertrophy markers, histopathological changes, and cardiac function were markedly ameliorated by oral administration of Daph in mice. We found that Daph significantly reduced the reactive oxygen species (ROS) generation, increased the nuclear translocation of Nrf2, and consequently, reinstated the protein levels of NAD(P)H quinone dehydrogenase1 (NQO1), heme oxygenase-1 (HO-1), and other antioxidants in the heart. Besides, Daph significantly inhibited the TAC-induced accumulation of ECM components, including α-smooth muscle actin (α-SMA), collagen I, collagen III, and fibronectin, and interfered with the TGF-β1/Smad2/3 signaling axis. Further studies revealed that TAC-induced terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive nuclei and the protein levels of Bax/Bcl2 ratio and cleaved caspase 3 were substantially decreased by Daph treatment. We further characterized the effect of Daph on angiotensin II (Ang-II)-stimulated H9c2 cardiomyoblast cells and observed that Daph markedly decreased the Ang-II induced increase in cell size, production of ROS, and proteins associated with apoptosis and fibrosis. Mechanistically, Daph alone treatment enhanced the protein levels of Nrf2, NQO1, and HO-1 in H9c2 cells. The inhibition of this axis by Si-Nrf2 transfection abolished the protective effect of Daph in H9c2 cells. Taken together, Daph effectively counteracted the TAC-induced cardiac hypertrophy and fibrosis by improving the Nrf2/HO-1 axis and inhibiting the TGF-β1/Smad2/3 signaling axis.

Effects of berbamine against myocardial ischemia/reperfusion injury: Activation of the 5' adenosine monophosphate-activated protein kinase/nuclear factor erythroid 2-related factor pathway and changes in the mitochondrial state

This study was designed to investigate whether berbamine (BA)-induced cardioprotective effects were related to 5' adenosine monophosphate-activated protein kinase (AMPK)/nuclear factor erythroid 2-related factor (Nrf2) signaling and changes in the mitochondria in myocardial ischemia/reperfusion (I/R) injury. C57/BL6 mice were exposed to BA (10 mg/kg/d), with or without administration of the AMPK specific inhibitor compound C (5 mg/kg/d) or the Nrf2 specific inhibitor ML-385 (30 mg/kg/d), and then subjected to a myocardial I/R operation. As expected, BA significantly improved post-ischemic cardiac function, reduced infarct size and apoptotic cell death, decreased oxidative stress, and improved the mitochondrial state. Furthermore, BA markedly increased AMPK activation, Nrf2 nuclear translocation, and the levels of NAD(P)H quinone dehydrogenase and heme oxygenase-1. Nevertheless, these BA-induced changes were abrogated by compound C. In addition, ML-385 also canceled the cardioprotective effects of BA but had little effect on AMPK activation. Our results demonstrate that BA alleviates myocardial I/R injury and the mitochondrial state by inhibiting apoptosis and oxidative stress via the AMPK/Nrf2 signaling pathway.

LCZ696 Ameliorates Isoproterenol-Induced Acute Heart Failure in Rats by Activating the Nrf2 Signaling Pathway

Objective

LCZ696 (sacubitril/valsartan) is an angiotensin II (Ang II) type 1 receptor-neprilysin inhibitor, with effects of immunosuppression, anti-inflammation, antiapoptosis, and antioxidation. The present study was aimed at determining whether LCZ696 has a protective effect against isoproterenol-induced acute heart failure (AHF) in rats.

Methods

SD rats were randomly divided into four groups: control group, HF group, LCZ696 group, and enalapril group. The cardiac function of rats was evaluated using echocardiographic parameters, heart weight (HW), serum levels of cardiac troponin I (cTnI), and lactate dehydrogenase (LDH). HE is staining, which was used to determine the pathological damage of rat myocardial tissue. Also, we measured oxidative stress markers including reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT). Finally, the expression of Nrf2 signaling pathway-related proteins was determined using Western blot.

Results

Compared with the HF group, LCZ696 could significantly improve cardiac function and myocardial injury in rats and reduce AHF-induced oxidative stress. In addition, the results of Western blot confirmed that LCZ696 could upregulate the expression of Nrf2 and HO-1 while decreasing Keap1 expression.

Conclusion

LCZ696 ameliorates isoproterenol-induced AHF in rats by alleviating oxidative stress injury and activating the Nrf2 signaling pathway.

New Progress in the Molecular Regulations and Therapeutic Applications in Cardiac Oxidative Damage Caused by Pressure Overload

Chronic pressure overload is a key risk factor for mortality due to its subsequent development of heart failure, in which the underlying molecular mechanisms remain vastly undetermined. In this review, we updated the latest advancements for investigating the role and relevant mechanisms of oxidative stress involved in the pathogenesis of pressure-overload-induced cardiomyopathy and cardiac dysfunction, focusing on significant biological sources of reactive oxygen species (free radical) production, antioxidant defenses, and their association with the cardiac metabolic remodeling in the stressed heart. We also summarize the newly developed preclinical therapeutic approaches in animal models for pressure-overload-induced myocardial damage. This review aims to enhance the current understanding of the mechanisms of chronic hypertensive heart failure and potentially improve the development of better therapeutic strategies for the associated diseases.

Trimethylamine N-Oxide Promotes Autoimmunity and a Loss of Vascular Function in Toll-like Receptor 7-Driven Lupus Mice

Plasma levels of trimethylamine N-oxide (TMAO) are elevated in lupus patients. We analyzed the implication of TMAO in autoimmunity and vascular dysfunction of the murine model of systemic lupus erythematosus (SLE) induced by the activation of the Toll-like receptor (TLR)7 with imiquimod (IMQ). Female BALB/c mice were randomly divided into four groups: untreated control mice, control mice treated with the trimethylamine lyase inhibitor 3,3-dimethyl-1-butanol (DMB), IMQ mice, and IMQ mice treated with DMB. The DMB-treated groups were administered the substance in their drinking water for 8 weeks. Treatment with DMB reduced plasma levels of TMAO in mice with IMQ-induced lupus. DMB prevents the development of hypertension, reduces disease progression (plasma levels of anti-dsDNA autoantibodies, splenomegaly, and proteinuria), reduces polarization of T lymphocytes towards Th17/Th1 in secondary lymph organs, and improves endothelial function in mice with IMQ-induced lupus. The deleterious vascular effects caused by TMAO appear to be associated with an increase in vascular oxidative stress generated by increased NADPH oxidase activity, derived in part from the vascular infiltration of Th17/Th1 lymphocytes, and reduced nrf2-driven antioxidant defense. In conclusion, our findings identified the bacterial-derived TMAO as a regulator of immune system, allowing for the development of autoimmunity and endothelial dysfunction in SLE mice.

Advanced Microparticulate/Nanoparticulate Respirable Dry Powders of a Selective RhoA/Rho Kinase (Rock) Inhibitor for Targeted Pulmonary Inhalation Aerosol Delivery

Pulmonary hypertension (PH) is a progressive disease that eventually leads to heart failure and potentially death for some patients. There are many unique advantages to treating pulmonary diseases directly and non-invasively by inhalation aerosols and dry powder inhalers (DPIs) possess additional unique advantages. There continues to be significant unmet medical needs in the effective treatment of PH that target the underlying mechanisms. To date, there is no FDA-approved DPI indicated for the treatment of PH. Fasudil is a novel RhoA/Rho kinase (ROCK) inhibitor that has shown great potential in effectively treating pulmonary hypertension. This systematic study is the first to report on the design and development of DPI formulations comprised of respirable nanoparticles/microparticles using particle engineering design by advanced spray drying. In addition, comprehensive physicochemical characterization, in vitro aerosol aerosol dispersion performance with different types of human DPI devices, in vitro cell-drug dose response cell viability of different human respiratory cells from distinct lung regions, and in vitro transepithelial electrical resistance (TEER) as air-interface culture (AIC) demonstrated that these innovative DPI fasudil formulations are safe on human lung cells and have high aerosol dispersion performance properties.

Protection of the enhanced Nrf2 deacetylation and its downstream transcriptional activity by SIRT1 in myocardial ischemia/reperfusion injury

Nrf2, the master gene transcriptor of antioxidant proteins, and SIRT1, the unique Class III histone deacetylase of sirtuins, have been involved in protecting myocardial ischemia/reperfusion (MI/R) injury. However, whether the protective effect of SIRT1 is directly related to the deacetylation of Nrf2 in the pathology of MI/R remains to be investigated. The current study was designed to evaluate the regulation of Nrf2 deacetylation and transcriptional activity by SIRT1 in MI/R. Hypoxia/reoxygenation (H/R) cardiomyocytes and MI/R mice were used to assess the role of SIRT1 in Nrf2 activation. Oxidative stress, cardiac function, LDH release, ROS and infarct size were also evaluated. We found that Nrf2 physically interacted with SIRT1 not only in normal and H/R cardiomyocytes in vitro, but also in Sham or I/R hearts in vivo. Adenovirus induced SIRT1 overexpression resulted in protected H/R induced cell death, accompanied by declined LDH release. Through MI/R in vivo, cardiac overexpression of SIRT1 led to ameliorated cardiac function and infarct size, as well as the decreased cardiac oxidative stress. Notably, such beneficial actions of SIRT1 were blocked by the Nrf2 silence. Mechanically, acetylation of Nrf2 was significantly decreased by SIRT1 overexpression in cardiomyocytes or in whole hearts, which upregulated the downstream signaling pathway of Nrf2. Taken together, we uncovered a clue, for the first time that SIRT1 physically interacts with Nrf2. The cardioprotective effect of SIRT1 overexpression against MI/R is associated with the increased Nrf2 deacetylation and activity. These findings have offered a direct proof and new perspective of post-translational modification in the understanding of oxidative stress and MI/R treatment.

Ferroptosis and its emerging roles in cardiovascular diseases

Ferroptosis is a new form of regulated cell death (RCD) driven by iron-dependent lipid peroxidation, which is morphologically and mechanistically distinct from other forms of RCD including apoptosis, autophagic cell death, pyroptosis and necroptosis. Recently, ferroptosis has been found to participate in the development of various cardiovascular diseases (CVDs) including doxorubicin-induced cardiotoxicity, ischemia/reperfusion-induced cardiomyopathy, heart failure, aortic dissection and stroke. Cardiovascular homeostasis is indulged in delicate equilibrium of assorted cell types composing the heart or vessels, and how ferroptosis contributes to the pathophysiological responses in CVD progression is unclear. Herein, we reviewed recent discoveries on the basis of ferroptosis and its involvement in CVD pathogenesis, together with related therapeutic potentials, aiming to provide insights on fundamental mechanisms of ferroptosis and implications in CVDs and associated disorders.

PGC-1α protects from myocardial ischaemia-reperfusion injury by regulating mitonuclear communication

The recovery of blood supply after a period of myocardial ischaemia does not restore the heart function and instead results in a serious dysfunction called myocardial ischaemia‐reperfusion injury (IRI), which involves several complex pathophysiological processes. Mitochondria have a wide range of functions in maintaining the cellular energy supply, cell signalling and programmed cell death. When mitochondrial function is insufficient or disordered, it may have adverse effects on myocardial ischaemia‐reperfusion and therefore mitochondrial dysfunction caused by oxidative stress a core molecular mechanism of IRI. Peroxisome proliferator‐activated receptor gamma co‐activator 1α (PGC‐1α) is an important antioxidant molecule found in mitochondria. However, its role in IRI has not yet been systematically summarized. In this review, we speculate the role of PGC‐1α as a key regulator of mitonuclear communication, which may interacts with nuclear factor, erythroid 2 like ‐1 and ‐2 (NRF‐1/2) to inhibit mitochondrial oxidative stress, promote the clearance of damaged mitochondria, enhance mitochondrial biogenesis, and reduce the burden of IRI.

Rho Kinase Inhibition by Fasudil Attenuates Adriamycin-Induced Chronic Heart Injury

Adriamycin (ADR)-induced chronic heart injury (CHI) is a serious complication of chemotherapy. The present study was designed to assess the ability of fasudil, a Rho kinase inhibitor, to prevent ADR-induced CHI. Forty male 6-week-old C57BL6 mice were randomly divided into the following four groups: (1) control group, (2) CHI induced by adriamycin (ADR group), (3) CHI plus low dose fasudil (ADR + L group), and (4) CHI plus high dose fasudil (ADR + H group). Animals from groups 2-4 received ADR (2.5 mg/kg, i.p.) once a week for 8 weeks, and the control group received saline. Meanwhile, the animals in groups 3-4 received 2 mg/kg/day or 10 mg/kg/day fasudil, respectively. After measurement of cardiac functions, blood samples were collected for biochemical assays. The hearts were excised for histological, immunohistochemistry and western blot study, respectively. Adriamycin produced evident cardiac damage revealed by cardiac functions changes: decreased left ventricular fractional shortening (FS), left ventricular ejection fraction (EF), increased left ventricular volume, cardiac injury marker changes (increased creatine kinase, lactate dehydrogenase), antioxidant enzymes activity changes (decreased superoxide dismutase), and lipid peroxidation (elevated malondialdehyde) to the control group. Fasudil treatment notably ameliorated ADR-induced cardiac damage, restored heart function, suppressed cell apoptosis and senescence, ameliorated redox imbalance, and DNA damage. Fasudil has a protective effect on ADR-induced chronic heart injury, which partially attributed to its antioxidant, anti-apoptotic effects of inhibiting the RhoA/Rho kinase (ROCK) signaling pathway.

Ferulic Acid Ameliorates Isoproterenol-Induced Heart Failure by Decreasing Oxidative Stress and Inhibiting Cardiocyte Apoptosis via Activating Nrf2 Signaling Pathway in Rats

Ferulic acid (FA) has potential therapeutic effects in multiple diseases including cardiovascular diseases. However, the effect and molecular basis of FA in heart failure (HF) has not been thoroughly elucidated. Herein, we investigated the roles and mechanisms of FA in HF in isoproterenol (ISO)-induced HF rat model. Results found that FA ameliorated cardiac dysfunction, alleviated oxidative stress, reduced cell/myocardium injury-related enzyme plasma level, inhibited cardiocyte apoptosis in ISO-induced HF rat models. Moreover, FA reduced the co-localization of Keap1 and nuclear factor-E2-related factor 2 (Nrf2) in heart tissues of ISO-induced HF rats, and FA alleviated the inhibitory effects of ISO on expressions of p-Nrf2, heme oxygenase-1 (HO-1) and reduced nicotinamide adenine dinucleotide phosphate quinone dehydrogenase 1 (NQO1). Additionally, Nrf2 signaling pathway inhibitor ML385 showed adverse effects. FA weakened the effects of ML385 in ISO-induced HF rat models. Collectively, FA ameliorated HF by decreasing oxidative stress and inhibiting cardiocyte apoptosis via activating Nrf2 pathway in ISO-induced HF rats. Our data elucidated the underling molecular mechanism and provided a novel insight into the cardioprotective function of FA, thus suggested the therapeutic potential of FA in HF treatment.

Effect of Heavy Metal Contamination in the Environment on Antioxidant Function in Wumeng Semi-fine Wool Sheep in Southwest China

Many environmental accidents have led to worldwide heavy metal pollution, raising concern about heavy metal toxicity in Southwest China. To study the effects of Cd and Pb in the environment on antioxidant function in Wumeng semi-fine wool sheep, contents of Cu, Zn, Mn, Mo, Fe, Se, Cd, and Pb were measured in irrigation water, soil, herbage, and animal tissues. Hematological and biochemical parameters were also determined. The concentrations of Cu, Zn, Cd, and Pb in affected samples of irrigation water, soil, herbage, and tissues were significantly higher than those in the control (P < 0.01). There was no significant difference in other element contents between affected pastures and control areas. The occurrence of anemia affected Wumeng semi-fine wool sheep. The activities of SOD, CAT, and GSH-Px in affected animals were significantly decreased than those in the control (P < 0.01). Content of MDA in serum in affected animals was significantly increased than that in control (P < 0.01). Serum T-AOC in affected animal was significantly lower than that in control (P < 0.01). Consequently, it is suggested that heavy metal contamination in natural habitat caused serious harm to antioxidant function in Wumeng semi-fine wool sheep.

NRF2 in Cardiovascular Diseases: a Ray of Hope!

Heart failure is a worldwide pandemic influencing 26 million individuals worldwide and is expanding. Imbalanced redox homeostasis in cardiac cells alters the structure and function of the cells, which leads to contractile dysfunction, myocardial hypertrophy, and fibrosis in chronic heart failure. Various targets and agents acting on these such as siRNA, miRNA, interleukin-1, opioids, vasodilators, and SGLT2 inhibitors are being evaluated for heart failure, and nuclear factor erythroid 2-related factor 2 (NRF2) is one of them. NRF2 is a master transcription factor which is expressed in most of the tissues and exhibits a major role in amplification of the antioxidant pathways associated with the enzymes present in myocardium. Increased ROS generation and PI3K-Akt signaling can activate the receptor NRF2. Various in vitro and in vivo and few clinical studies suggested NRF2 may possess a potential for targeting oxidative stress-induced cardiovascular diseases including heart failures. All these studies collectively propose that upregulation of NRF2 will attenuate the increase in hemodynamic stress and provide beneficial role in cardiovascular diseases. The current review shall familiarize readers about the regulations and functions of NRF2. We have also discussed the current evidences suggesting beneficial role of NRF2 activators in heart failure. Graphical abstract.

The deleterious role of the prostaglandin E2 EP3 receptor in angiotensin II hypertension

Angiotensin II (ANG II) plays a key role in regulating blood pressure and inflammation. Prostaglandin E₂ (PGE₂) signals through four different G protein-coupled receptors, eliciting a variety of effects. We reported that activation of the EP₃ receptor reduces cardiac contractility. More recently, we have shown that overexpression of the EP₄ receptor is protective in a mouse myocardial infarction model. We hypothesize in this study that the relative abundance of EP₃ and EP₄ receptors is a major determinant of end-organ damage in the diseased heart. Thus EP₃ is detrimental to cardiac function and promotes inflammation, whereas antagonism of the EP₃ receptor is protective in an ANG II hypertension (HTN) model. To test our hypothesis, male 10- to 12-wk-old C57BL/6 mice were anesthetized with isoflurane and osmotic minipumps containing ANG II were implanted subcutaneously for 2 wk. We found that antagonism of the EP₃ receptor using L798,106 significantly attenuated the increase in blood pressure with ANG II infusion. Moreover, antagonism of the EP₃ receptor prevented a decline in cardiac function after ANG II treatment. We also found that 10- to 12-wk-old EP₃-transgenic mice, which overexpress EP₃ in the cardiomyocytes, have worsened cardiac function. In conclusion, activation or overexpression of EP₃ exacerbates end-organ damage in ANG II HTN. In contrast, antagonism of the EP₃ receptor is beneficial and reduces cardiac dysfunction, inflammation, and HTN.NEW & NOTEWORTHY This study is the first to show that systemic treatment with an EP₃ receptor antagonist (L798,106) attenuates the angiotensin II-induced increase in blood pressure in mice. The results from this project could complement existing hypertension therapies by combining blockade of the EP₃ receptor with antihypertensive drugs.

Evaluation of nine active components of Lu-Jiao Fang in normal and hypertrophic rat myocardia via LC-MS/MS

Lu-Jiao Fang (LJF), a traditional Chinese medicine prescription, can improve the cardiac function of chronic heart failure (CHF) patients; however, knowledge about the cardiac distribution of LJF, especially in CHF animal models, is rather limited. This work aimed to explore the cardiac distribution of LJF in pressure overload-induced CHF rats at the last gavage administration of LJF after 30 weeks of treatment. LC-MS/MS methods for analyzing nine active components (i.e. loganin, hesperidin, epimedin C, icariin, psoralen, isopsoralen, baohuoside I, morroniside and specnuezhenide) of LJF in cardiac tissue samples were established, and the components were then analyzed in left ventricular wall (LVW) and right ventricular wall (RVW) in parallel at same time point postdose for three dose groups. The results showed that most analytical component levels in LVW (hypertrophic myocardium) were only 39-74% of those in RVW (normal myocardium); however, psoralen and isopsoralen levels in LVW were equal to or even greater than the levels in RVW, suggesting that the hypertrophic myocardium tissue affinity of psoralen and isopsoralen might overcome the negative effect of decreased blood flow on distribution. This study indicated that the pathological state may influence drug distribution, and the efficacy of psoralen and isopsoralen for improving CHF deserves further investigation.

Postinfarction exercise training alleviates cardiac dysfunction and adverse remodeling via mitochondrial biogenesis and SIRT1/PGC-1α/PI3K/Akt signaling

Exercise training mitigates cardiac pathological remodeling and dysfunction caused by myocardial infarction (MI), but its underlying cellular and molecular mechanisms remain elusive. Our present study in an in vivo rat model of MI determined the impact of post-MI exercise training on myocardial fibrosis, mitochondrial biogenesis, antioxidant capacity, and ventricular function. Adult male rats were randomized into: (a) Sedentary control group; (b) 4-week treadmill exercise training group; (c) Sham surgery group; (d) MI group with permanent ligation of left anterior descending coronary artery and kept sedentary during post-MI period; and (e) post-MI 4-week exercise training group. Results indicated that exercise training significantly improved post-MI left ventricular function and reduced markers of cardiac fibrosis. Exercise training also significantly attenuated MI-induced mitochondrial damage and oxidative stress, which were associated with enhanced antioxidant enzyme expression and/or activity and total antioxidant capacity in the heart. Interestingly, the adaptive activation of the SIRT1/PGC-1α/PI3K/Akt signaling following MI was further enhanced by post-MI exercise training, which is likely responsible for exercise-induced cardioprotection and mitochondrial biogenesis. In conclusion, this study has provided novel evidence on the activation of SIRT1/PGC-1α/PI3K/Akt pathway, which may mediate exercise-induced cardioprotection through reduction of cardiac fibrosis and oxidative stress, as well as improvement of mitochondrial integrity and biogenesis in post-MI myocardium.

RhoGTPase in Vascular Disease

Ras-homologous (Rho)A/Rho-kinase pathway plays an essential role in many cellular functions, including contraction, motility, proliferation, and apoptosis, inflammation, and its excessive activity induces oxidative stress and promotes the development of cardiovascular diseases. Given its role in many physiological and pathological functions, targeting can result in adverse effects and limit its use for therapy. In this review, we have summarized the role of RhoGTPases with an emphasis on RhoA in vascular disease and its impact on endothelial, smooth muscle, and heart and lung fibroblasts. It is clear from the various studies that understanding the regulation of RhoGTPases and their regulators in physiology and pathological conditions is required for effective targeting of Rho.

Sfrp1 attenuates TAC-induced cardiac dysfunction by inhibiting Wnt signaling pathway- mediated myocardial apoptosis in mice

Background

Hemodynamic overload causes cardiac hypertrophy leading to heart failure. Wnt signaling pathway was reported activated in heart failure. Secreted frizzled related protein 1 (Sfrp1) is a suppressor of Wnt signaling activation. The aim of the present study was to investigate the protective effect of Sfrp1 on hemodynamic overload- induced cardiac dysfunction.

Methods

A mice transverse aortic constriction (TAC)- induced heart failure model was established. A recombinant adeno-associated virus 9 (AAV9) vector was used to deliver Sfrp1 gene into myocardium. Fluorescence and immunohistochemistry staining was used to evaluate the effectiveness of viral vector delivery. Invasive hemodynamic examination was used to evaluate cardiac systolic and diastolic functions. Myocardium apoptosis was detected by TUNEL assay. The expression levels of Sfrp1, β-catenin, caspase3, Bax, Bcl-2 and c-Myc were measured by Western blotting.

Results

Increased mean arterial pressure and impaired cardiac function confirmed the establishment of TAC model. Sfrp1 protein expression was effectively increased in myocardium of mice treated with AAV9-Sfrp1 viral vector. The viral vector administration improved both systolic and diastolic cardiac functions by reducing myocardial apoptosis in TAC mice. The expression levels of β-catenin, caspase3 and Bax were significantly reduced while the expression levels of Bcl-2 and c-Myc were dramatically increased in myocardium by the viral vector treatment in TAC mice.

Conclusions

AAV9 viral vector delivered sfrp1 expression gene into myocardium, which attenuated TAC-induced cardiac dysfunction by inhibiting Wnt signaling pathway activation- mediated apoptosis.