Redox Regulation of Cardiac ASK1 (Apoptosis Signal-Regulating Kinase 1) Controls p38-MAPK (Mitogen-Activated Protein Kinase) and Orchestrates Cardiac Remodeling to Hypertension

Mitogen-activated protein kinase signalling in rat hearts during postnatal development: MAPKs, MAP3Ks, MAP4Ks and DUSPs

Mammalian cardiomyocytes become terminally-differentiated during the perinatal period. In rodents, cytokinesis ceases after a final division cycle immediately after birth. Nuclear division continues and most cardiomyocytes become binucleated by ∼11 days. Subsequent growth results from an increase in cardiomyocyte size. The mechanisms involved remain under investigation. Mitogen-activated protein kinases (MAPKs) regulate cell growth/death: extracellular signal-regulated kinases 1/2 (ERK1/2) promote proliferation, whilst c-Jun N-terminal kinases (JNKs) and p38-MAPKs respond to cellular stresses. We assessed their regulation in rat hearts during postnatal development (2, 7, 14, and 28 days, 12 weeks) during which time there was rapid, substantial downregulation of mitosis/cytokinesis genes (Cenpa/e/f, Aurkb, Anln, Cdca8, Orc6) with lesser downregulation of DNA replication genes (Orcs1-5, Mcms2-7). MAPK activation was assessed by immunoblotting for total and phosphorylated (activated) kinases. Total ERK1/2 was downregulated, but not JNKs or p38-MAPKs, whilst phosphorylation of all MAPKs increased relative to total protein albeit transiently for JNKs. These profiles differed from activation of Akt (also involved in cardiomyocyte growth). Dual-specificity phosphatases, upstream MAPK kinase kinases (MAP3Ks), and MAP3K kinases (MAP4Ks) identified in neonatal rat cardiomyocytes by RNASeq were differentially regulated during postnatal cardiac development. The MAP3Ks that we could assess by immunoblotting (RAF kinases and Map3k3) showed greater downregulation of the protein than mRNA. MAP3K2/MAP3K3/MAP4K5 were upregulated in human failing heart samples and may be part of the "foetal gene programme" of re-expressed genes in disease. Thus, MAPKs, along with kinases and phosphatases that regulate them, potentially play a significant role in postnatal remodelling of the heart.

Fas Apoptosis Inhibitory Molecule 2 Inhibits Pathological Cardiac Hypertrophy by Regulating the MAPK Signaling Pathway

BACKGROUND

Pathological cardiac hypertrophy stands as a pivotal mechanism contributing to diverse cardiovascular diseases, ultimately leading to heart failure. Despite its clinical significance, the intricate molecular mechanisms instigating pathological cardiac hypertrophy remain inadequately understood. In this study, we aim to further reveal its complex pathogenesis by exploring the role of Fas apoptotic inhibitory molecule 2 (FAIM2) in modulating pathological cardiac hypertrophy.

METHODS AND RESULTS

We used phenylephrine-induced hypertrophic cardiomyocytes and also generated cardiac-specific knockout mice and adeno-associated virus serotype 9-Faim2 mice to evaluate the function of FAIM2 in pathological myocardial hypertrophy. Furthermore, unbiased RNA-sequencing analysis was used to identify the direct target and corresponding molecular events contributing to FAIM2 function. Ultimately, our study revealed a downregulation of FAIM2 expression in phenylephrine-induced hypertrophic cardiomyocytes and pressure overload-induced hypertrophic hearts. FAIM2 exhibited a significant attenuation of phenylephrine-induced enlargement of primary neonatal rat cardiomyocytes, whereas FAIM2 knockdown aggravated the hypertrophic response. Furthermore, Faim2 gene knockout significantly exacerbated cardiac hypertrophy and heart fibrosis in vivo. Mechanistic investigations unveiled that FAIM2 exerts its inhibitory effect by suppressing TAK1-JNK1/2-p38 MAPK signaling cascades, thereby mitigating cardiac hypertrophy.

CONCLUSIONS

Our findings position FAIM2 as a novel negative regulator of pathological cardiac hypertrophy through its inhibitory action on mitogen-activated protein kinase signaling activation. This identification of FAIM2's role provides crucial insights that may pave the way for the development of effective therapeutic strategies aimed at mitigating pathological cardiac hypertrophy, addressing a critical need in cardiovascular disease management.

Cardiac tumour necrosis factor receptor-associated factor 7 mediates the ubiquitination of apoptosis signal-regulating kinase 1 and aggravates cardiac hypertrophy

AIMS

Cardiac remodelling is a common pathophysiological process in the development of various cardiovascular diseases, but there is still a lack of effective interventions. Tumour necrosis receptor-associated factor 7 (TRAF7) belongs to the tumour necrosis factor receptor-associated factor family and plays an important role in biological processes. Previous studies have shown that TRAF7 mutations lead to congenital defects and malformations of the heart. However, the molecular mechanisms of TRAF7 in the underlying pathogenesis of pathological cardiac hypertrophy remain unknown. We aim to study the molecular mechanisms and effects of TRAF7 in cardiac remodelling and whether it has the potential to become a therapeutic target for cardiac remodelling.

METHODS AND RESULTS

The pressure overload-induced cardiac hypertrophy model in mice was established via transverse aortic constriction (TAC) surgery, and cardiomyocytes were treated with phenylephrine (PE) to induce hypertrophic phenotype. Levels of cardiac dysfunction and remodelling were measured with echocardiography and tissue or cell staining. RNA sequencing, western blot, qRT-PCR, co-immunoprecipitation, and in vivo ubiquitination assays were used to explore the molecular mechanisms. The results showed that the expression of TRAF7 increased gradually during the development of hypertrophy. Accordingly, TRAF7 significantly exacerbated the PE-induced enlargement of primary neonatal Sprague-Dawley rat cardiomyocytes, whereas TRAF7 knockdown alleviated the hypertrophic phenotype in primary cardiomyocytes. Cardiac-specific overexpression of TRAF7 accelerated hypertrophic phenotype in mice and cardiac-specific Traf7 conditional knockout mice improved hypertrophic phenotype induced by TAC. Mechanistically, TRAF7 directly interacted with apoptosis signal-regulating kinase-1 (ASK1) and promoted ASK1 phosphorylation by mediating the K63-linked ubiquitination of ASK1 in response to PE stimulation, which then promoted ASK1 activation and downstream signalling during cardiac hypertrophy. Notably, the pro-hypertrophic effect of TRAF7 was largely blocked by GS4997 in vitro and cardiac-specific Ask1 conditional knockout in vivo.

CONCLUSION

In summary, we identified TRAF7 as an essential regulator during cardiac hypertrophy, and modulation of the regulatory axis between TRAF7 and ASK1 could be a novel therapeutic strategy to prevent this pathological process.

Heart failure with preserved ejection fraction: The role of inflammation

Heart failure (HF) is a debilitating clinical syndrome affecting 64.3 million patients worldwide. More than 50% of HF cases are attributed to HF with preserved ejection fraction (HFpEF), an entity growing in prevalence and mortality. Although recent breakthroughs reveal the prognostic benefits of sodium-glucose co-transporter 2 inhibitors (SGLT2i) in HFpEF, there is still a lack of effective pharmacological therapy available. This highlights a major gap in medical knowledge that must be addressed. Current evidence attributes HFpEF pathogenesis to an interplay between cardiometabolic comorbidities, inflammation, and renin-angiotensin-aldosterone-system (RAAS) activation, leading to cardiac remodelling and diastolic dysfunction. However, conventional RAAS blockade has demonstrated limited benefits in HFpEF, which emphasises that alternative therapeutic targets should be explored. Presently, there is limited literature examining the use of anti-inflammatory HFpEF therapies despite growing evidence supporting its importance in disease progression. Hence, this review aims to explore current perspectives on HFpEF pathogenesis, including the importance of inflammation-driven cardiac remodelling and the therapeutic potential of anti-inflammatory therapies.

The Impact of Hydrogen Sulfide in the Paraventricular Nucleus on the MAPK Pathway in High Salt-Induced Hypertension

ABSTRACT

The hypothalamic paraventricular nucleus (PVN) plays a central role in regulating cardiovascular activity and blood pressure. We administered hydroxylamine hydrochloride (HA), a cystathionine-β-synthase inhibitor, into the PVN to suppress endogenous hydrogen sulfide and investigate its effects on the mitogen-activated protein kinase (MAPK) pathway in high salt (HS)-induced hypertension. We randomly divided 40 male Dahl salt-sensitive rats into 4 groups: the normal salt (NS) + PVN vehicle group, the NS + PVN HA group, the HS + PVN vehicle group, and the HS + PVN HA group, with 10 rats in each group. The rats in the NS groups were fed a NS diet containing 0.3% NaCl, while the HS groups were fed a HS diet containing 8% NaCl. The mean arterial pressure was calculated after noninvasive measurement using an automatic sphygmomanometer to occlude the tail cuff once a week. HA or vehicle was infused into the bilateral PVN using Alzet osmotic mini pumps for 6 weeks after the hypertension model was successfully established. We measured the levels of H 2 S in the PVN and plasma norepinephrine using enzyme linked immunosorbent assay. In addition, we assessed the parameters of the MAPK pathway, inflammation, and oxidative stress through western blotting, immunohistochemical analysis, or real-time polymerase chain reaction. In this study, we discovered that decreased levels of endogenous hydrogen sulfide in the PVN contributed to the onset of HS-induced hypertension. This was linked to the activation of the MAPK signaling pathway, proinflammatory cytokines, and oxidative stress in the PVN, as well as the activation of the sympathetic nervous system.

The Pathophysiological Associations Between Obesity, NAFLD, and Atherosclerotic Cardiovascular Diseases

Obesity, non-alcoholic fatty liver disease (NAFLD), and atherosclerotic cardiovascular diseases are common and growing public health concerns. Previous epidemiological studies unfolded the robust correlation between obesity, NAFLD, and atherosclerotic cardiovascular diseases. Obesity is a well-known risk factor for NAFLD, and both of them can markedly increase the odds of atherosclerotic cardiovascular diseases. On the other hand, significant weight loss achieved by lifestyle modification, bariatric surgery, or medications, such as semaglutide, can concomitantly improve NAFLD and atherosclerotic cardiovascular diseases. Therefore, certain pathophysiological links are involved in the development of NAFLD in obesity, and atherosclerotic cardiovascular diseases in obesity and NAFLD. Moreover, recent studies indicated that simultaneously targeting several mechanisms by tirzepatide and retatrutide leads to greater weight loss and markedly improves the complications of metabolic syndrome. These findings remind the importance of a mechanistic viewpoint for breaking the association between obesity, NAFLD, and atherosclerotic cardiovascular diseases. In this review article, we mainly focus on shared pathophysiological mechanisms, including insulin resistance, dyslipidemia, GLP1 signaling, inflammation, oxidative stress, mitochondrial dysfunction, gut dysbiosis, renin-angiotensin-aldosterone system (RAAS) overactivity, and endothelial dysfunction. Most of these pathophysiological alterations are primarily initiated by obesity. The development of NAFLD further exacerbates these molecular and cellular alterations, leading to atherosclerotic cardiovascular disease development or progression as the final manifestation of molecular perturbation. A better insight into these mechanisms makes it feasible to develop new multi-target approaches to simultaneously unhinge the deleterious chain of events linking obesity and NAFLD to atherosclerotic cardiovascular diseases.

METTL3-mediated m6A modification of OTUD1 aggravates press overload induced myocardial hypertrophy by deubiquitinating PGAM5

Background: Pathological cardiac hypertrophy, a condition that contributes to heart failure, is characterized by its intricate pathogenesis. The meticulous regulation of protein function, localization, and degradation is a crucial role played by deubiquitinating enzymes in cardiac pathophysiology. This study clarifies the participation and molecular mechanism of OTUD1 (OTU Deubiquitinase 1) in pathological cardiac hypertrophy. Methods: We generated a cardiac-specific Otud1 knockout mouse line (Otud1-CKO) and adeno-associated virus serotype 9-Otud1 mice to determine the role of Otud1 in cardiac hypertrophy. Its impact on cardiomyocytes enlargement was investigated using the adenovirus. RNA immunoprecipitation was used to validate the specific m6a methyltransferase interacted with OTUD1 transcript. RNA sequencing in conjunction with immunoprecipitation-mass spectrometry analysis was employed to identify the direct targets of OTUD1. A series of depletion mutant plasmids were constructed to detect the interaction domain of OTUD1 and its targets. Results: Ang II-stimulated neonatal rat cardiac myocytes and mice hearts subjected to transverse aortic constriction (TAC) showed increased protein levels of Otud1. Cardiac hypertrophy and dysfunction were less frequent in Otud1-CKO mice during TAC treatment, while Otud1 overexpression worsened cardiac hypertrophy and remodeling. METTL3 mediated m6A modification of OTUD1 transcript promoted mRNA stability and elevated protein expression. In terms of pathogenesis, Otud1 plays a crucial role in cardiac hypertrophy by targeting Pgam5, leading to the robust activation of the Ask1-p38/JNK signal pathway to accelerate cardiac hypertrophy. Significantly, the pro-hypertrophy effects of Otud1 overexpression were largely eliminated when Ask1 knockdown. Conclusion: Our findings confirm that targeting the OTUD1-PGAM5 axis holds significant potential as a therapeutic approach for heart failure associated with pathological hypertrophy.

Anshen Shumai Decoction inhibits post-infarction inflammation and myocardial remodeling through suppression of the p38 MAPK/c-FOS/EGR1 pathway

Anshen Shumai Decoction (ASSMD) is traditionally employed to manage coronary artery disease arrhythmias. Its protective efficacy against myocardial infarction remains to be elucidated. This investigation employed a rat model of myocardial infarction, achieved through the ligation of the left anterior descending (LAD) coronary artery, followed by a 28-day administration of ASSMD. The study observed the decoction's mitigative impact on myocardial injury, with gene regulation effects discerned through transcriptomic analysis. Furthermore, ASSMD's influence on cardiomyocyte apoptosis and fibrotic protein secretion was assessed using an embryonic rat cardiomyocyte cell line (H9c2) under hypoxic conditions and rat cardiac fibroblasts subjected to normoxic culture conditions with TGF-β. A functional rescue assay involving overexpression of FOS and Early Growth Response Factor 1 (EGR1), combined with inhibition of the p38 Mitogen-activated Protein Kinase (MAPK) pathway, was conducted. Results indicated that ASSMD significantly curtailed cardiomyocyte apoptosis and myocardial fibrosis in infarcted rats, primarily by downregulating FOS and EGR1 gene expression and inhibiting the upstream p38 MAPK pathway. These actions of ASSMD culminated in reduced expression of pro-apoptotic, collagen, and fibrosis-associated proteins, conferring myocardial protection and anti-fibrotic effects on cardiac fibroblasts.

The role of serine/threonine protein kinases in cardiovascular disease and potential therapeutic methods

Protein phosphorylation is an important link in a variety of signaling pathways, and most of the important life processes in cells involve protein phosphorylation. Based on the amino acid residues of phosphorylated proteins, protein kinases can be categorized into the following families: serine/threonine protein kinases, tyrosine-specific protein kinases, histidine-specific protein kinases, tryptophan kinases, and aspartate/glutamyl protein kinases. Of all the protein kinases, most are serine/threonine kinases, where serine/threonine protein kinases are protein kinases that catalyze the phosphorylation of serine or threonine residues on target proteins using ATP as a phosphate donor. The current socially accepted classification of serine/threonine kinases is to divide them into seven major groups: protein kinase A, G, C (AGC), CMGC, Calmodulin-dependent protein kinase (CAMK), Casein kinase (CK1), STE, Tyrosine kinase (TKL) and others. After decades of research, a preliminary understanding of the specific classification and respective functions of serine/threonine kinases has entered a new period of exploration. In this paper, we review the literature of the previous years and introduce the specific signaling pathways and related therapeutic modalities played by each of the small protein kinases in the serine/threonine protein kinase family, respectively, in some common cardiovascular system diseases such as heart failure, myocardial infarction, ischemia-reperfusion injury, and diabetic cardiomyopathy. To a certain extent, the current research results, including molecular mechanisms and therapeutic methods, are fully summarized and a systematic report is made for the prevention and treatment of cardiovascular diseases in the future.

Reactive oxygen species in hypertension

Hypertension is a leading risk factor for stroke, heart disease and chronic kidney disease. Multiple interacting factors and organ systems increase blood pressure and cause target-organ damage. Among the many molecular elements involved in the development of hypertension are reactive oxygen species (ROS), which influence cellular processes in systems that contribute to blood pressure elevation (such as the cardiovascular, renal, immune and central nervous systems, or the renin-angiotensin-aldosterone system). Dysregulated ROS production (oxidative stress) is a hallmark of hypertension in humans and experimental models. Of the many ROS-generating enzymes, NADPH oxidases are the most important in the development of hypertension. At the cellular level, ROS influence signalling pathways that define cell fate and function. Oxidative stress promotes aberrant redox signalling and cell injury, causing endothelial dysfunction, vascular damage, cardiovascular remodelling, inflammation and renal injury, which are all important in both the causes and consequences of hypertension. ROS scavengers reduce blood pressure in almost all experimental models of hypertension; however, clinical trials of antioxidants have yielded mixed results. In this Review, we highlight the latest advances in the understanding of the role and the clinical implications of ROS in hypertension. We focus on cellular sources of ROS, molecular mechanisms of oxidative stress and alterations in redox signalling in organ systems, and their contributions to hypertension.

Therapeutic Potentials of Medicinal Leech in Chinese Medicine

The use of medicinal leeches in clinical therapy has been employed for a long time, as it was originally recognized for exerting antithrombin effects. These effects were due to the ability of the leech to continuously suck blood while attached to human skin. According to Chinese Pharmacopoei, leeches used in traditional Chinese medicine mainly consist of Whitmania pigra Whitman, Hirudo nipponia Whitman, and Whitmania acranulata, but the latter two species are relatively scarce. The main constituents of leeches are protein and peptide macromolecules. They can be categorized into two categories based on their pharmacological effects. One group consists of active ingredients that directly target the coagulation system, such as hirudin, heparin, and histamine, which are widely known. The other group comprises protease inhibitor components like Decorsin and Hementin. Among these, hirudin secreted by the salivary glands of the leech is the most potent thrombin inhibitor and served as the sole remedy for preventing blood clotting until the discovery of heparin. Additionally, leeches play a significant role in various traditional Chinese medicine formulations. In recent decades, medicinal leeches have been applied in fields including anti-inflammatory treatment, cardiovascular disease management, antitumor treatment, and many other medical conditions. In this review, we present a comprehensive overview of the historical journey and medicinal applications of leeches in various medical conditions, emphasizing their pharmaceutical significance within traditional Chinese medicine. This review offers valuable insights for exploring additional therapeutic opportunities involving the use of leeches in various diseases and elucidating their underlying mechanisms for future research.

Striatin plays a major role in angiotensin II-induced cardiomyocyte and cardiac hypertrophy in mice in vivo

The three striatins (STRN, STRN3, STRN4) form the core of STRiatin-Interacting Phosphatase and Kinase (STRIPAK) complexes. These place protein phosphatase 2A (PP2A) in proximity to protein kinases thereby restraining kinase activity and regulating key cellular processes. Our aim was to establish if striatins play a significant role in cardiac remodelling associated with cardiac hypertrophy and heart failure. All striatins were expressed in control human hearts, with up-regulation of STRN and STRN3 in failing hearts. We used mice with global heterozygote gene deletion to assess the roles of STRN and STRN3 in cardiac remodelling induced by angiotensin II (AngII; 7 days). Using echocardiography, we detected no differences in baseline cardiac function or dimensions in STRN+/- or STRN3+/- male mice (8 weeks) compared with wild-type littermates. Heterozygous gene deletion did not affect cardiac function in mice treated with AngII, but the increase in left ventricle mass induced by AngII was inhibited in STRN+/- (but not STRN3+/-) mice. Histological staining indicated that cardiomyocyte hypertrophy was inhibited. To assess the role of STRN in cardiomyocytes, we converted the STRN knockout line for inducible cardiomyocyte-specific gene deletion. There was no effect of cardiomyocyte STRN knockout on cardiac function or dimensions, but the increase in left ventricle mass induced by AngII was inhibited. This resulted from inhibition of cardiomyocyte hypertrophy and cardiac fibrosis. The data indicate that cardiomyocyte striatin is required for early remodelling of the heart by AngII and identify the striatin-based STRIPAK system as a signalling paradigm in the development of pathological cardiac hypertrophy.

Iron-triggered signaling via ETS1 and the p38/JNK MAPK pathway regulates Bmp6 expression

BMP6 is an iron-sensing cytokine whose transcription in liver sinusoidal endothelial cells (LSECs) is enhanced by high iron levels, a step that precedes the induction of the iron-regulatory hormone hepcidin. While several reports suggested a cell-autonomous induction of Bmp6 by iron-triggered signals, likely via sensing of oxidative stress by the transcription factor NRF2, other studies proposed the dominant role of a paracrine yet unidentified signal released by iron-loaded hepatocytes. To further explore the mechanisms of Bmp6 transcriptional regulation, we used female mice aged 10-11 months, which are characterized by hepatocytic but not LSEC iron accumulation, and no evidence of systemic iron overload. We found that LSECs of aged mice exhibit increased Bmp6 mRNA levels as compared to young controls, but do not show a transcriptional signature characteristic of activated NFR2-mediated signaling in FACS-sorted LSECs. We further observed that primary murine LSECs derived from both wild-type and NRF2 knock-out mice induce Bmp6 expression in response to iron exposure. By analyzing transcriptomic data of FACS-sorted LSECs from aged versus young mice, as well as early after iron citrate injections, we identified ETS1 as a candidate transcription factor involved in Bmp6 transcriptional regulation. By performing siRNA-mediated knockdown, small-molecule treatments, and chromatin immunoprecipitation in primary LSECs, we show that Bmp6 transcription is regulated by iron via ETS1 and p38/JNK MAP kinase-mediated signaling, at least in part independently of NRF2. Thereby, these findings identify the new components of LSEC iron sensing machinery broadly associated with cellular stress responses.

Melanoma differentiation-associated protein 5 prevents cardiac hypertrophy via apoptosis signal-regulating kinase 1-c-Jun N-terminal kinase/p38 signaling

Pathological cardiac hypertrophy (CH) is driven by maladaptive changes in myocardial cells in response to pressure overload or other stimuli. CH has been identified as a significant risk factor for the development of various cardiovascular diseases, ultimately resulting in heart failure. Melanoma differentiation-associated protein 5 (MDA5), encoded by interferon-induced with helicase C domain 1 (IFIH1), is a cytoplasmic sensor that primarily functions as a detector of double-stranded ribonucleic acid (dsRNA) viruses in innate immune responses; however, its role in CH pathogenesis remains unclear. Thus, the aim of this study was to examine the relationship between MDA5 and CH using cellular and animal models generated by stimulating neonatal rat cardiomyocytes with phenylephrine and by performing transverse aortic constriction on mice, respectively. MDA5 expression was upregulated in all models. MDA5 deficiency exacerbated myocardial pachynsis, fibrosis, and inflammation in vivo, whereas its overexpression hindered CH development in vitro. In terms of the underlying molecular mechanism, MDA5 inhibited CH development by promoting apoptosis signal-regulating kinase 1 (ASK1) phosphorylation, thereby suppressing c-Jun N-terminal kinase/p38 signaling pathway activation. Rescue experiments using an ASK1 activation inhibitor confirmed that ASK1 phosphorylation was essential for MDA5-mediated cell death. Thus, MDA5 protects against CH and is a potential therapeutic target.

Mitochondrial Dysfunction in Heart Failure: From Pathophysiological Mechanisms to Therapeutic Opportunities

Mitochondrial dysfunction, a feature of heart failure, leads to a progressive decline in bioenergetic reserve capacity, consisting in a shift of energy production from mitochondrial fatty acid oxidation to glycolytic pathways. This adaptive process of cardiomyocytes does not represent an effective strategy to increase the energy supply and to restore the energy homeostasis in heart failure, thus contributing to a vicious circle and to disease progression. The increased oxidative stress causes cardiomyocyte apoptosis, dysregulation of calcium homeostasis, damage of proteins and lipids, leakage of mitochondrial DNA, and inflammatory responses, finally stimulating different signaling pathways which lead to cardiac remodeling and failure. Furthermore, the parallel neurohormonal dysregulation with angiotensin II, endothelin-1, and sympatho-adrenergic overactivation, which occurs in heart failure, stimulates ventricular cardiomyocyte hypertrophy and aggravates the cellular damage. In this review, we will discuss the pathophysiological mechanisms related to mitochondrial dysfunction, which are mainly dependent on increased oxidative stress and perturbation of the dynamics of membrane potential and are associated with heart failure development and progression. We will also provide an overview of the potential implication of mitochondria as an attractive therapeutic target in the management and recovery process in heart failure.

Liensinine improves AngII-induced vascular remodeling via MAPK/TGF-β1/Smad2/3 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Liensinine(Lien, C37H42N2O6) is an alkaloid compound from plumula nelumbinis that demonstrates an antihypertensive effect. The protective effects of Lien on target organs during hypertension are still unclear.

AIM OF THE STUDY

This study aimed to understand the mechanism of Lien during the treatment of hypertension, with emphasis on vascular protection.

MATERIALS AND METHODS

Lien was extracted and isolated from plumula nelumbinis for further study. In vivo model of Ang II-induced hypertension, non-invasive sphygmomanometer was used to detect the blood pressure in and out of the context of Lien intervention. Ultrasound was used to detect the abdominal aorta pulse wave and media thickness of hypertensive mice, and RNA sequencing was used to detect the differential genes and pathways of blood vessels. The intersection of Lien and MAPK protein molecules was detected by molecular interconnecting technique. The pathological conditions of abdominal aorta vessels of mice were observed by HE staining. The expression of PCNA, α-SMA, Collagen Type Ⅰ and Collagen Type Ⅲ proteins were detected by IHC. The collagen expression in the abdominal aorta was detected by Sirius red staining. The MAPK/TGF-β1/Smad2/3 signaling and the protein expression of PCNA and α-SMA was detected by Western blot. In vitro, MAPK/TGF-β1/Smad2/3 signaling and the protein expression of PCNA and α-SMA were detected by Western blot, and the expression of α-SMA was detected by immunofluorescence; ELISA was used to detect the effect of ERK/MAPK inhibitor PD98059 on Ang Ⅱ-induced TGF-β1secrete; and the detection TGF-β1and α-SMA protein expression by Western blot; Western blot was used to detect the effect of ERK/MAPK stimulant12-O-tetradecanoyl phorbol-13-acetate (TPA) on the protein expression of TGF-β1 and α-SMA.

RESULTS

Lien displayed an antihypertensive effect on Ang Ⅱ-induced hypertension, reducing the pulse wave conduction velocity of the abdominal aorta and the thickness of the abdominal aorta vessel wall, ultimately improving the pathological state of blood vessels. RNA sequencing further indicated that the differential pathways expressed in the abdominal aorta of hypertensive mice were enriched in proliferation-related markers compared with the Control group. The profile of differentially expressed pathways was ultimately reversed by Lien. Particularly, MAPK protein demonstrated good binding with the Lien molecule. In vivo, Lien inhibited Ang Ⅱ-induced abdominal aorta wall thickening, reduced collagen deposition in the ventral aortic vessel, and prevented the occurrence of vascular remodeling by inhibiting MAPK/TGF-β1/Smad2/3 signaling activation. In addition, Lien inhibited the activation of Ang II-induced MAPK and TGF-β1/Smad2/3 signaling, attenuating the expression of PCNA and inhibiting the reduction of α-SMA, collectively playing a role in the inhibition of Ang Ⅱ-induced hypertensive vascular remodeling. PD98059 alone could inhibit Ang Ⅱ-induced elevation of TGF-β1 and the decrease of α-SMA expression. Further, PD98059 combined with Lien had no discrepancy with the inhibitors alone. Simultaneously TPA alone could significantly increase the expression of TGF-β1 and decrease the expression of α-SMA. Further, Lien could inhibit the effect of TPA.

CONCLUSION

This study helped clarify the protective mechanism of Lien during hypertension, elucidating its role as an inhibitor of vascular remodeling and providing an experimental basis for the research and development of novel antihypertensive therapies.

Oxidative Stress and Endoplasmic Reticular Stress Interplay in the Vasculopathy of Hypertension

Under physiologic conditions, reactive oxygen species (ROS) function as signalling molecules that control cell function. However, in pathologic conditions, increased generation of ROS triggers oxidative stress, which plays a role in vascular changes associated with hypertension, including endothelial dysfunction, vascular reactivity, and arterial remodelling (termed the vasculopathy of hypertension). The major source of ROS in the vascular system is NADPH oxidase (NOX). Increased NOX activity drives vascular oxidative stress in hypertension. Molecular mechanisms underlying vascular damage in hypertension include activation of redox-sensitive signalling pathways, post-translational modification of proteins, and oxidative damage of DNA and cytoplasmic proteins. In addition, oxidative stress leads to accumulation of proteins in the endoplasmic reticulum (ER) (termed ER stress), with consequent activation of the unfolded protein response (UPR). ER stress is emerging as a potential player in hypertension as abnormal protein folding in the ER leads to oxidative stress and dysregulated activation of the UPR promotes inflammation and injury in vascular and cardiac cells. In addition, the ER engages in crosstalk with exogenous sources of ROS, such as mitochondria and NOX, which can amplify redox processes. Here we provide an update of the role of ROS and NOX in hypertension and discuss novel concepts on the interplay between oxidative stress and ER stress.

Participation of ASK-1 in the cardiomyocyte-protective role of mechanical ventilation in a rat model of myocardial infarction

Non-invasive positive-pressure ventilation (NIPPV) has been demonstrated to exhibit a cardioprotective function in a rat model of myocardial infarction (MI). However, the mechanism underlying NIPPV-mediated MI progression requires further investigation. We aimed to investigate the effectiveness and corresponding mechanism of NIPPV in an acute MI-induced heart failure (HF) rat model. Thirty each of healthy wild type (WT) and apoptosis signal-regulating kinase 1 (ASK-1)-deficient rats were enrolled in this study. MI models were established via anterior descending branch ligation of the left coronary artery. The corresponding data indicated that NIPPV treatment reduced the heart infarct area, myocardial fibrosis degree, and cardiac function loss in MI rats, and ameliorated apoptosis and reactive oxygen species (ROS) levels in the heart tissue. Furthermore, the expression level of ASK-1 level, a key modulator of the ROS-induced extrinsic apoptosis pathway, was upregulated in the heart tissues of MI rats, but decreased after NIPPV treatment. Meanwhile, the downstream cleavage of caspase-3, caspase-9, and PARP, alongside p38 phosphorylation and FasL expression, exhibited a similar trend to that of ASK-1 expression. The involvement of ASK-1 in NIPPV-treated MI in ASK-1-deficient rats was examined. Although MI modeling indicated that cardiac function loss was alleviated in ASK-1-deficient rats, NIPPV treatment did not confer any clear efficiency in cardiac improvement in ASK-1-knockdown rats with MI modeling. Nonetheless, NIPPV inhibited ROS-induced extrinsic apoptosis in the heart tissues of rats with MI by regulating ASK-1 expression, and subsequently ameliorated cardiac function loss and MI-dependent pathogenic changes in the heart tissue.

Bone marrow mesenchymal stem cell-derived exosomes carrying E3 ubiquitin ligase ITCH attenuated cardiomyocyte apoptosis by mediating apoptosis signal-regulated kinase-1

BACKGROUND

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes have been verified to perform an effective role in treating acute myocardial infarction (MI). Herein, we aimed to investigate the role of BMSC-derived exosomes carrying itchy E3 ubiquitin ligase (ITCH) in MI and the underlying mechanism involved.

METHODS

BMSCs were isolated from rat bone marrow and exosomes were extracted using ultra-high speed centrifugation. Exosomes uptake by cardiomyoblasts was determined by PKH-67 staining. Rat cardiomyoblast cell line H9C2 was stimulated by hypoxia, as in vitro model. H9C2 cell apoptosis was determined by flow cytometry. Cell viability was examined by cell counting kit-8 assay. Western blotting was performed to determine the expression of ITCH, apoptosis signal-regulated kinase-1 (ASK1), and apoptotic-related protein cleaved-caspase 3 and Bcl-2. Ubiquitination assay was employed to measure the levels of ASK1 ubiquitination.

RESULTS

Exosomes derived from BMSCs were endocytosed by H9C2 cardiomyoblasts. BMSC-Exo downregulated cleaved-caspase 3 expression, upregulated Bcl-2 expression, further suppressed H9C2 cell apoptosis under hypoxia treatment, meanwhile the expression of ASK1 was downregulated, and similar effects were observed in BMSC-cultured supernatant (BMSC-S). However, these effects were reversed by exosome inhibitor GW4869. BMSC-derived exosomes enhanced ASK1 ubiquitination and degradation. Mechanically, exosomes of ITCH-knockdown BMSCs promoted H9C2 cell apoptosis and upregulated ASK1 expression. Overexpression of ITCH enhanced ASK1 ubiquitination and degradation. Further, the protein expression of ASK1 and cleaved-caspase 3 was upregulated and Bcl-2 protein expression was downregulated. ITCH-knockdown BMSC exosomes increased cardiomyoblast apoptosis.

CONCLUSION

BMSC-derived exosomes carrying ITCH suppressed cardiomyoblast apoptosis, promoted cardiomyoblast viability, and improved myocardial injury in AMI by mediating ASK1 ubiquitination.

The Impacts of Animal-Based Diets in Cardiovascular Disease Development: A Cellular and Physiological Overview

Cardiovascular disease (CVD) is the leading cause of death in the United States, and diet plays an instrumental role in CVD development. Plant-based diets have been strongly tied to a reduction in CVD incidence. In contrast, animal food consumption may increase CVD risk. While increased serum low-density lipoprotein (LDL) cholesterol concentrations are an established risk factor which may partially explain the positive association with animal foods and CVD, numerous other biochemical factors are also at play. Thus, the aim of this review is to summarize the major cellular and molecular effects of animal food consumption in relation to CVD development. Animal-food-centered diets may (1) increase cardiovascular toll-like receptor (TLR) signaling, due to increased serum endotoxins and oxidized LDL cholesterol, (2) increase cardiovascular lipotoxicity, (3) increase renin-angiotensin system components and subsequent angiotensin II type-1 receptor (AT1R) signaling and (4) increase serum trimethylamine-N-oxide concentrations. These nutritionally mediated factors independently increase cardiovascular oxidative stress and inflammation and are all independently tied to CVD development. Public policy efforts should continue to advocate for the consumption of a mostly plant-based diet, with the minimization of animal-based foods.

Nrf2: A Main Responsive Element of the Toxicity Effect Caused by Trichothecene (T-2) Mycotoxin

T-2 toxin, the most toxic type A trichothecene mycotoxin, is produced by Fusarium, and is widely found in contaminated feed and stored grains. T-2 toxin is physicochemically stable and is challenging to eradicate from contaminated feed and cereal, resulting in food contamination that is inescapable and poses a major hazard to both human and animal health, according to the World Health Organization. Oxidative stress is the upstream cause of all pathogenic variables, and is the primary mechanism through which T-2 toxin causes poisoning. Nuclear factor E2-related factor 2 (Nrf2) also plays a crucial part in oxidative stress, iron metabolism and mitochondrial homeostasis. The major ideas and emerging trends in future study are comprehensively discussed in this review, along with research progress and the molecular mechanism of Nrf2's involvement in the toxicity impact brought on by T-2 toxin. This paper could provide a theoretical foundation for elucidating how Nrf2 reduces oxidative damage caused by T-2 toxin, and a theoretical reference for exploring target drugs to alleviate T-2 toxin toxicity with Nrf2 molecules.

P38 MAPK activated ADAM17 mediates ACE2 shedding and promotes cardiac remodeling and heart failure after myocardial infarction

BACKGROUND

Heart failure (HF) after myocardial infarction (MI) is a prevalent disease with a poor prognosis. Relieving pathological cardiac remodeling and preserving cardiac function is a critical link in the treatment of post-MI HF. Thus, more new therapeutic targets are urgently needed. The expression of ADAM17 is increased in patients with acute MI, but its functional role in post-MI HF remains unclear.

METHODS

To address this question, we examined the effects of ADAM17 on the severity and prognosis of HF within 1 year of MI in 152 MI patients with or without HF. In mechanistic studies, the effects of ADAM17 on ventricular remodeling and systolic function were extensively assessed at the tissue and cellular levels by establishing animal model of post-MI HF and in vitro hypoxic cell model.

RESULTS

High levels of ADAM17 predicted a higher incidence of post-MI HF, poorer cardiac function and higher mortality. Animal studies demonstrated that ADAM17 promoted the occurrence of post-MI HF, as indicated by increased infarct size, cardiomyocyte hypertrophy, myocardial interstitial collagen deposition and cardiac failure. ADAM17 knock down significantly improved pathological cardiac remodeling and cardiac function in mice with MI. Mechanistically, activated ADAM17 inhibited the cardioprotective effects of ACE2 by promoting hydrolytic shedding of the transmembrane protein ACE2 in cardiomyocytes, which subsequently mediated the occurrence of cardiac remodeling and the progression of heart failure. Moreover, the activation of ADAM17 in hypoxic cardiomyocytes was dependent on p38 MAPK phosphorylation at threonine 735.

CONCLUSIONS

These data highlight a novel and important mechanism for ADAM17 to cause post-MI HF, which will hopefully be a new potential target for early prediction or intervention of post-MI HF. Video abstract.

Hypothalamic Oxytocin Neuron Activation Attenuates Intermittent Hypoxia-Induced Hypertension and Cardiac Dysfunction in an Animal Model of Sleep Apnea

BACKGROUND

Obstructive sleep apnea is a prevalent and poorly treated cardiovascular disease that leads to hypertension and autonomic imbalance. Recent studies that restore cardiac parasympathetic tone using selective activation of hypothalamic oxytocin neurons have shown beneficial cardiovascular outcomes in animal models of cardiovascular disease. This study aimed to determine if chemogenetic activation of hypothalamic oxytocin neurons in animals with existing obstructive sleep apnea-induced hypertension would reverse or blunt the progression of autonomic and cardiovascular dysfunction.

METHODS

Two groups of rats were exposed to chronic intermittent hypoxia (CIH), a model of obstructive sleep apnea, for 4 weeks to induce hypertension. During an additional 4 weeks of exposure to CIH, 1 group was treated with selective activation of hypothalamic oxytocin neurons while the other group was untreated.

RESULTS

Hypertensive animals exposed to CIH and treated with daily hypothalamic oxytocin neuron activation had lower blood pressure, faster heart rate recovery times after exercise, and improved indices of cardiac function compared with untreated hypertensive animals. Microarray analysis suggested that, compared with treated animals, untreated animals had gene expression profiles associated with cellular stress response activation, hypoxia-inducible factor stabilization, and myocardial extracellular matrix remodeling and fibrosis.

CONCLUSIONS

In animals already presenting with CIH-induced hypertension, chronic activation of hypothalamic oxytocin neurons blunted the progression of hypertension and conferred cardioprotection after an additional 4 weeks of CIH exposure. These results have significant clinical translation for the treatment of cardiovascular disease in patients with obstructive sleep apnea.

Seaweed Sargassum aquifolium extract ameliorates cardiotoxicity induced by doxorubicin in rats

Doxorubicin (DOX) is a potent anticancer drug with adverse cardiotoxic effects. Alginates are multifunctional biopolymers and polyelectrolytes derived from the cell walls of brown seaweeds. They are nontoxic, biocompatible, and biodegradable, and hence, utilized in several biomedical and pharmaceutical applications. Here, we investigated the potential cardioprotective effect of thermally treated sodium alginate (TTSA), which was extracted and purified from the seaweed Sargassum aquifolium, in treating acute DOX cardiotoxicity and apoptotic pathways in rats. UV-visible spectroscopy, Fourier-transform infrared, and nuclear magnetic resonance (1H-NMR) spectroscopy techniques were used to characterize TTSA. CK-MB and AST levels in sera samples were determined. The expression levels of Erk-2 (MAPK-1) and iNOS genes were investigated by quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression levels of Erk-2, anti-apoptotic p53, and caspase-3 were analyzed using western blotting and ELISA. For the in vivo studies, sixty rats were randomly divided equally into six groups and treated with DOX, followed by TTSA. We revealed that treatment with TTSA, which has low molecular weight and enhanced antioxidant properties, improved DOX-mediated cardiac dysfunction and alleviated DOX-induced myocardial apoptosis. Furthermore, TTSA exhibited a cardioprotective effect against DOX-induced cardiac toxicity, indicated by the increased expression of MAPK-1 (Erk2) and iNOS genes, which are implicated in the adaptive responses regulating DOX-induced myocardial damage. Moreover, TTSA significantly (p < 0.05) suppressed caspase-3 and upregulated anti-apoptotic protein p53 expression. TTSA also rebalanced the cardiomyocyte redox potential by significantly (p < 0.05) increasing the levels of endogenous antioxidant enzymes, including catalase and superoxide dismutase. Our findings suggest that TTSA, particularly at a dose of 400 mg/kg b.w., is a potential prophylactic supplement for treating acute DOX-linked cardiotoxicity.

Impact of a TAK-1 inhibitor as a single or as an add-on therapy to riociguat on the metabolic reprograming and pulmonary hypertension in the SUGEN5416/hypoxia rat model

Background: Despite increasing evidence suggesting that pulmonary arterial hypertension (PAH) is a complex disease involving vasoconstriction, thrombosis, inflammation, metabolic dysregulation and vascular proliferation, all the drugs approved for PAH mainly act as vasodilating agents. Since excessive TGF-β signaling is believed to be a critical factor in pulmonary vascular remodeling, we hypothesized that blocking TGFβ-activated kinase 1 (TAK-1), alone or in combination with a vasodilator therapy (i.e., riociguat) could achieve a greater therapeutic benefit.

Methods: PAH was induced in male Wistar rats by a single injection of the VEGF receptor antagonist SU5416 (20 mg/kg) followed by exposure to hypoxia (10%O2) for 21 days. Two weeks after SU5416 administration, vehicle, riociguat (3 mg/kg/day), the TAK-1 inhibitor 5Z-7-oxozeaenol (OXO, 3 mg/kg/day), or both drugs combined were administered for 7 days. Metabolic profiling of right ventricle (RV), lung tissues and PA smooth muscle cells (PASMCs) extracts were performed by magnetic resonance spectroscopy, and the differences between groups analyzed by multivariate statistical methods.

Results:In vitro, riociguat induced potent vasodilator effects in isolated pulmonary arteries (PA) with negligible antiproliferative effects and metabolic changes in PASMCs. In contrast, 5Z-7-oxozeaenol effectively inhibited the proliferation of PASMCs characterized by a broad metabolic reprogramming but had no acute vasodilator effects. In vivo, treatment with riociguat partially reduced the increase in pulmonary arterial pressure (PAP), RV hypertrophy (RVH), and pulmonary vascular remodeling, attenuated the dysregulation of inosine, glucose, creatine and phosphocholine (PC) in RV and fully abolished the increase in lung IL-1β expression. By contrast, 5Z-7-oxozeaenol significantly reduced pulmonary vascular remodeling and attenuated the metabolic shifts of glucose and PC in RV but had no effects on PAP or RVH. Importantly, combined therapy had an additive effect on pulmonary vascular remodeling and induced a significant metabolic effect over taurine, amino acids, glycolysis, and TCA cycle metabolism via glycine-serine-threonine metabolism. However, it did not improve the effects induced by riociguat alone on pulmonary pressure or RV remodeling. None of the treatments attenuated pulmonary endothelial dysfunction and hyperresponsiveness to serotonin in isolated PA.

Conclusion: Our results suggest that inhibition of TAK-1 induces antiproliferative effects and its addition to short-term vasodilator therapy enhances the beneficial effects on pulmonary vascular remodeling and RV metabolic reprogramming in experimental PAH.

Inhibiting O-GlcNAcylation impacts p38 and Erk1/2 signaling and perturbs cardiomyocyte hypertrophy

The dynamic cycling of O-linked GlcNAc (O-GlcNAc) on and off Ser/Thr residues of intracellular proteins, termed O-GlcNAcylation, is mediated by the conserved enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase. O-GlcNAc cycling is important in homeostatic and stress responses, and its perturbation sensitizes the heart to ischemic and other injuries. Despite considerable progress, many molecular pathways impacted by O-GlcNAcylation in the heart remain unclear. The mitogen-activated protein kinase (MAPK) pathway is a central signaling cascade that coordinates developmental, physiological, and pathological responses in the heart. The developmental or adaptive arm of MAPK signaling is primarily mediated by Erk kinases, while the pathophysiologic arm is mediated by p38 and Jnk kinases. Here, we examine whether O-GlcNAcylation affects MAPK signaling in cardiac myocytes, focusing on Erk1/2 and p38 in basal and hypertrophic conditions induced by phenylephrine. Using metabolic labeling of glycans coupled with alkyne-azide "click" chemistry, we found that Erk1/2 and p38 are O-GlcNAcylated. Supporting the regulation of p38 by O-GlcNAcylation, the OGT inhibitor, OSMI-1, triggers the phosphorylation of p38, an event that involves the NOX2-Ask1-MKK3/6 signaling axis and also the noncanonical activator Tab1. Additionally, OGT inhibition blocks the phenylephrine-induced phosphorylation of Erk1/2. Consistent with perturbed MAPK signaling, OSMI-1-treated cardiomyocytes have a blunted hypertrophic response to phenylephrine, decreased expression of cTnT (key component of the contractile apparatus), and increased expression of maladaptive natriuretic factors Anp and Bnp. Collectively, these studies highlight new roles for O-GlcNAcylation in maintaining a balanced activity of Erk1/2 and p38 MAPKs during hypertrophic growth responses in cardiomyocytes.

Oxidants and Antioxidants in the Redox Biochemistry of Human Red Blood Cells

Red blood cells (RBCs) are exposed to both external and internal sources of oxidants that challenge their integrity and compromise their physiological function and supply of oxygen to tissues. Autoxidation of oxyhemoglobin is the main source of endogenous RBC oxidant production, yielding superoxide radical and then hydrogen peroxide. In addition, potent oxidants from other blood cells and the surrounding endothelium can reach the RBCs. Abundant and efficient enzymatic systems and low molecular weight antioxidants prevent most of the damage to the RBCs and also position the RBCs as a sink of vascular oxidants that allow the body to maintain a healthy circulatory system. Among the antioxidant enzymes, the thiol-dependent peroxidase peroxiredoxin 2, highly abundant in RBCs, is essential to keep the redox balance. A great part of the RBC antioxidant activity is supported by an active glucose metabolism that provides reducing power in the form of NADPH via the pentose phosphate pathway. There are several RBC defects and situations that generate oxidative stress conditions where the defense mechanisms are overwhelmed, and these include glucose-6-phosphate dehydrogenase deficiencies (favism), hemoglobinopathies like sickle cell disease and thalassemia, as well as packed RBCs for transfusion that suffer from storage lesions. These oxidative stress-associated pathologies of the RBCs underline the relevance of redox balance in these anucleated cells that lack a mechanism of DNA-inducible antioxidant response and rely on a complex and robust network of antioxidant systems.

Guhong injection mitigates myocardial ischemia/reperfusion injury by activating GST P to inhibit ASK1-JNK/p38 pathway

BACKGROUND

Guhong injection (GHI), a novel compound preparation that is composed of a chemical drug, namely aceglutamide, and the aqueous extract of safflower (Carthamus tinctorius L.), exhibits extreme antioxidative, antiapoptotic, anti-inflammatory, and neuroprotective effects. Since oxidative stress, apoptosis, and inflammatory response are all the dominant mechanisms of myocardial ischemia/reperfusion (MI/R) injury, we probe into the protective mechanism of GHI on MI/R injury for the first time.

METHODS

In this research, we first employed molecular docking to determine whether three active ingredients in GHI, acetylglutamine (NAG), hydroxysafflor yellow A (HSYA), and syringin, possessed the potential activity to modulate the protein, glutathione S-transferase P (GST P). We further identified the protective effect of GHI on myocardial tissue with TTC staining, HE staining, TUNEL staining, and ELISA, and on H9c2 with flow cytometry and ELISA. We next explored whether the cardioprotective effect of GHI on left anterior descending ligation-reperfusion in rats and hypoxia/reoxygenation (H/R) in H9c2 cells was related to activate GST P to inhibit ASK1-JNK/p38 pathway via approaches of qRT-PCR and Western blot.

RESULTS

Results of molecular docking indicated that all three compounds spontaneously docked to GST P, among them the binding affinities of both HSYA and syringin to GST P were higher than NAG. In vivo, GHI reduced myocardial infarction size and mitigated myocardial pathological injury. In vitro, GHI enhanced cell viability and extenuated depolarization of mitochondrial membrane potential. In addition, the results of in vivo and in vitro studies demonstrated that the cardioprotection of GHI was associated with improving the mRNA and protein expression levels of GST P to modulate oxidative stress, and inhibiting the levels of mRNA expression and protein phosphorylation of ASK1, JNK, and p38. However, the suppressed effect of GHI on ASK1-JNK/p38 pathway was reversed by ethacrynic acid (EA, a GST inhibitor), indicating that the regulation of GHI on ASK1-JNK/p38 was related to the activity of GST P. Besides, the in vitro results of qRT-PCR and western-blot also certified that the inhibited JNK and p38 further reduced Bax expression and elevated Bcl-2 expression to reduce the expression of caspase-3 to exert anti-apoptosis effects.

CONCLUSION

Taken together, the cardioprotection of GHI mainly incarnated in activating GST P to relieve oxidation properties, thereby inhibiting ASK1-JNK/p38 pathway to suppress apoptosis.

Cardiomyocyte BRAF is a key signalling intermediate in cardiac hypertrophy in mice

Cardiac hypertrophy is necessary for the heart to accommodate an increase in workload. Physiological, compensated hypertrophy (e.g. with exercise) is reversible and largely due to cardiomyocyte hypertrophy. Pathological hypertrophy (e.g. with hypertension) is associated with additional features including increased fibrosis and can lead to heart failure. RAF kinases (ARAF/BRAF/RAF1) integrate signals into the extracellular signal-regulated kinase 1/2 cascade, a pathway implicated in cardiac hypertrophy, and activation of BRAF in cardiomyocytes promotes compensated hypertrophy. Here, we used mice with tamoxifen-inducible cardiomyocyte-specific BRAF knockout (CM-BRAFKO) to assess the role of BRAF in hypertension-associated cardiac hypertrophy induced by angiotensin II (AngII; 0.8 mg/kg/d, 7 d) and physiological hypertrophy induced by phenylephrine (40 mg/kg/d, 7 d). Cardiac dimensions/functions were measured by echocardiography with histological assessment of cellular changes. AngII promoted cardiomyocyte hypertrophy and increased fibrosis within the myocardium (interstitial) and around the arterioles (perivascular) in male mice; cardiomyocyte hypertrophy and interstitial (but not perivascular) fibrosis were inhibited in mice with CM-BRAFKO. Phenylephrine had a limited effect on fibrosis but promoted cardiomyocyte hypertrophy and increased contractility in male mice; cardiomyocyte hypertrophy was unaffected in mice with CM-BRAFKO, but the increase in contractility was suppressed and fibrosis increased. Phenylephrine induced a modest hypertrophic response in female mice and, in contrast with the males, tamoxifen-induced loss of cardiomyocyte BRAF reduced cardiomyocyte size, had no effect on fibrosis and increased contractility. The data identify BRAF as a key signalling intermediate in both physiological and pathological hypertrophy in male mice, and highlight the need for independent assessment of gene function in females.

Thioredoxin-interacting protein deficiency protects against severe acute pancreatitis by suppressing apoptosis signal-regulating kinase 1

Acute pancreatitis is a common acute inflammatory abdominal disease. When acute pancreatitis progresses to severe acute pancreatitis (SAP), it can lead to systemic inflammation and even multiple organ failure. Thioredoxin-interacting protein (TXNIP) is an important protein involved in redox reactions of the inflammatory response. However, the specific role of TXNIP in SAP remains unclear. In this study, we investigated the role of thioredoxin interacting protein (TXNIP) in acute pancreatitis when induced by high doses of arginine. We found that pancreatic damage and the inflammatory response associated with acute pancreatitis were largely restrained in TXNIP knock-out mice but were enhanced in mice overexpressing TXNIP. Interestingly, the phosphorylation of p38, JNK, and ASK1 diminished in TXNIP-KO mice with pancreatitis in comparison with wild-type mice. The role of oxidative stress in SAP was explored in two models: TXNIP and AVV-TXNIP. TXNIP knockdown or the inhibition of ASK1 by gs-4997 abrogated the increase in p-p38, p-JNK, and p-ASK1 in AR42J cells incubated with L-Arg. The administration of gs-4997 to mice with pancreatitis largely reduced the upregulation of IL-6, IL-1β, TNF-α, and MCP-1. Systemic inflammatory reactions and injury in the lungs and kidneys were assessed in TXNIP-KO and AVV-TXNIP mice with expected outcomes. In conclusion, TXNIP is a novel mediator of SAP and exerts action by regulating inflammatory responses and oxidative stress via the ASK1-dependent activation of the JNK/p38 pathways. Thus, targeting TXNIP may represent a promising approach to protect against SAP.

The high-intensity interval training mitigates the cardiac remodeling in spontaneously hypertensive rats

AIM

To evaluate the influence of high-intensity interval training (HIIT) on cardiac structural and functional characteristics and myocardial mitogen-activated protein kinase (MAPK) signaling in hypertensive rats.

METHODS

Male rats (12 months old) were divided into three groups: Wistar Kyoto rats (WKY, n = 8); sedentary spontaneously hypertensive rats (SED-SHR, n = 10), and trained spontaneously hypertensive rats (HIIT-SHR, n = 10). Systolic blood pressure (SBP), functional capacity, echocardiography, isolated papillary muscle, and gene expression of MAPK gene-encoding proteins associated with Elk1, cJun, ATF2, MEF2 were analyzed.

KEY FINDINGS

HIIT decreased SBP and increased functional capacity, left ventricular diastolic diameter, posterior wall thickness-left ventricle, relative wall thickness-left ventricle, and resting tension of the papillary muscle. In hypertensive rats, we observed a decrease in the gene-encoding ATF2 protein; this decrease was reversed by HIIT.

SIGNIFICANCE

The influence of HIIT in the SHR model in the compensated hypertension phase generated an increase in cardiac hypertrophy, attenuated myocardial diastolic dysfunction, lowered blood pressure, improved functional capacity, and reversed the alteration in gene-encoding ATF2 protein.

circCNN2 Accelerates Cell Proliferation and Invasion in Lung Squamous Cell Carcinoma via Regulating miR-184/E2F1 and Activating MAPK Signaling Pathway

Circular RNAs (circRNAs) have been demonstrated as potential biomarkers for the diagnosis and treatment of human diseases. Previous studies have unveiled the carcinogenic role of circRNA_102399 (circCNN2) in lung cancer. Through the UALCAN database, it was found that CNN2, the parent gene of circCNN2, was specifically highly expressed in human lung squamous cell carcinoma (LUSC) cells, but the regulatory mechanism of circCNN2 in LUSC is unclear. In this study, circCNN2 expression in LUSC cells was examined via RT-qPCR, and its effects on LUSC progression was verified through functional assays. The subcellular localization of circCNN2 was identified via FISH assay, and the underlying mechanism of circCNN2 on the activation of MAPK signaling pathway was determined through mechanism experiments. Results demonstrated that circCNN2 was upregulated in LUSC cells, and it promoted LUSC cell proliferation and invasion. Besides, circCNN2 acted as a competing endogenous RNA (ceRNA) to sponge miR-184 to upregulate E2F transcription factor 1 (E2F1) expression. Furthermore, it was verified that circCNN2 activated the generic mitogen-activated protein kinases (MAPK) signaling pathway through E2F1 and thus promoting LUSC progression. In a word, this study indicated that circCNN2 activated MAPK signaling pathway through the miR-184/E2F1 axis to promote proliferation and invasion of LUSC cells.

The Thioredoxin System of Mammalian Cells and Its Modulators

Oxidative stress involves the increased production and accumulation of free radicals, peroxides, and other metabolites that are collectively termed reactive oxygen species (ROS), which are produced as by-products of aerobic respiration. ROS play a significant role in cell homeostasis through redox signaling and are capable of eliciting damage to macromolecules. Multiple antioxidant defense systems have evolved to prevent dangerous ROS accumulation in the body, with the glutathione and thioredoxin/thioredoxin reductase (Trx/TrxR) systems being the most important. The Trx/TrxR system has been used as a target to treat cancer through the thiol–disulfide exchange reaction mechanism that results in the reduction of a wide range of target proteins and the generation of oxidized Trx. The TrxR maintains reduced Trx levels using NADPH as a co-substrate; therefore, the system efficiently maintains cell homeostasis. Being a master regulator of oxidation–reduction processes, the Trx-dependent system is associated with cell proliferation and survival. Herein, we review the structure and catalytic properties of the Trx/TrxR system, its role in cellular signaling in connection with other redox systems, and the factors that modulate the Trx system.

Of Mouse and Man: Cross-Species Characterization of Hypertensive Cardiac Remodeling

Hypertension is a major public health concern and poses a significant risk for sudden cardiac death (SCD). However, the characterisation of human tissues tends to be macroscopic, with little appreciation for the quantification of the pathological remodelling responsible for the advancement of the disease. While the components of hypertensive remodelling are well established, the timeline and comparative quantification of pathological changes in hypertension have not been shown before. Here, we sought to identify the phasing of cardiac remodelling with hypertension using post-mortem tissue from SCD patients with early and advanced hypertensive heart disease (HHD). In order to study and quantify the progression of phenotypic changes, human specimens were contrasted to a well-described angiotensin-II-mediated hypertensive mouse model. While cardiomyocyte hypertrophy is an early adaptive response in the mouse that stabilises in established hypertension and declines as the disease progresses, this finding did not translate to the human setting. In contrast, optimising fibrosis quantification methods and applying them to each setting identified perivascular fibrosis as the prevailing possible cause for overall disease progression. Indeed, assessing myocardial inflammation highlights CD45+ inflammatory cell infiltration that precedes fibrosis and is an early-phase event in response to elevated arterial pressures that may underscore perivascular remodelling. Along with aetiology insight, we highlight cross-species comparison for quantification of cardiac remodelling in human hypertension. As such, this platform could assist with the development of therapies specific to the disease phase rather than targeting global components of hypertension, such as blood pressure lowering.

Transcriptomics of angiotensin II-induced long noncoding and coding RNAs in endothelial cells

OBJECTIVE

Angiotensin II (Ang II)-induced endothelial dysfunction plays an important role in the pathogenesis of cardiovascular diseases such as systemic hypertension, cardiac hypertrophy and atherosclerosis. Recently, long noncoding RNAs (lncRNAs) have been shown to play an essential role in the pathobiology of cardiovascular diseases; however, the effect of Ang II on lncRNAs and coding RNAs expression in endothelial cells has not been evaluated. Accordingly, we sought to evaluate the expression profiles of lncRNAs and coding RNAs in endothelial cells following treatment with Ang II.

METHODS

Human umbilical vein endothelial cells (HUVECs) were cultured and treated with Ang II (10-6 mol/l) for 24 h. The cells were then profiled for the expression of lncRNAs and mRNAs using the Arraystar Human lncRNA Expression Microarray V3.0.

RESULTS

In HUVECs following Ang II treatment, from a total of 30 584 lncRNA targets screened, 25 targets were significantly upregulated, while 69 were downregulated. In the same HUVECs samples, from 26 106 mRNA targets screened, 28 targets were significantly upregulated and 67 were downregulated. Of the differentially expressed lncRNAs, RP11-354P11.2 and RP11-360F5.1 were the most upregulated (11-fold) and downregulated (three-fold) lncRNAs, respectively. Assigning the differentially regulated genes into functional groups using bioinformatics reveals numerous genes involved in the nucleotide excision repair and ECM-receptor interaction.

CONCLUSION

This is the first study to profile the Ang II-induced differentially expressed lncRNAs and mRNAs in human endothelial cells. Our results reveal novel targets and substantially extend the list of potential candidate genes involved in Ang II-induced endothelial dysfunction and cardiovascular diseases.

PKN2 deficiency leads both to prenatal congenital cardiomyopathy and defective angiotensin II stress responses

The protein kinase PKN2 is required for embryonic development and PKN2 knockout mice die as a result of failure in the expansion of mesoderm, cardiac development and neural tube closure. In the adult, cardiomyocyte PKN2 and PKN1 (in combination) are required for cardiac adaptation to pressure-overload. The specific role of PKN2 in contractile cardiomyocytes during development and its role in the adult heart remain to be fully established. We used mice with cardiomyocyte-directed knockout of PKN2 or global PKN2 haploinsufficiency to assess cardiac development and function using high resolution episcopic microscopy, MRI, micro-CT and echocardiography. Biochemical and histological changes were also assessed. Cardiomyocyte-directed PKN2 knockout embryos displayed striking abnormalities in the compact myocardium, with frequent myocardial clefts and diverticula, ventricular septal defects and abnormal heart shape. The sub-Mendelian homozygous knockout survivors developed cardiac failure. RNASeq data showed up-regulation of PKN2 in patients with dilated cardiomyopathy, suggesting an involvement in adult heart disease. Given the rarity of homozygous survivors with cardiomyocyte-specific deletion of PKN2, the requirement for PKN2 in adult mice was explored using the constitutive heterozygous PKN2 knockout. Cardiac hypertrophy resulting from hypertension induced by angiotensin II was reduced in these haploinsufficient PKN2 mice relative to wild-type littermates, with suppression of cardiomyocyte hypertrophy and cardiac fibrosis. It is concluded that cardiomyocyte PKN2 is essential for heart development and the formation of compact myocardium and is also required for cardiac hypertrophy in hypertension. Thus, PKN signalling may offer therapeutic options for managing congenital and adult heart diseases.

Daidzein Synergizes with Gefitinib to Induce ROS/JNK/c-Jun Activation and Inhibit EGFR-STAT/AKT/ERK Pathways to enhance Lung Adenocarcinoma cells chemosensitivity

Lung cancer is the major cause of cancer associated mortality. Mutations in EGFR have been implicated in lung cancer pathogenesis. Gefitinib (GF) is a RTKI (receptor tyrosine kinase inhibitor) first-choice drug for EGFR mutated advanced lung cancer. However, drug toxicity and cancer cell resistance lead to treatment failure. Consequently, new therapeutic strategies are urgently required. Therefore, this study was aimed at identifying tumor suppressive compounds that can synergistically improve Gefitinib chemosensitivity in the lung cancer treatment. Medicinal plants offer a vast platform for the development of novel anticancer agents. Daidzein (DZ) is an isoflavone compound extracted from soy plants and has been shown to possess many medicinal benefits. The anticancer potential of GF and DZ combination treatment was investigated using MTT, western blot, fluorescent microscopy imaging, flow cytometry and nude mice tumor xenograft techniques. Our results demonstrate that DZ synergistically induces c-Jun nuclear translocation through ROS/ASK1/JNK and downregulates EGFR-STAT/AKT/ERK pathways to activate apoptosis and a G0/G1 phase cell cycle blockade. In in-vivo, the combination treatment significantly suppressed A549 lung cancer cells tumor xenograft growth without noticeable toxicity. Daidzein supplements with current chemotherapeutic agents may well be an alternative strategy to improve the treatment efficacy of lung adenocarcinoma.

Reactive Oxygen Species Induced Pathways in Heart Failure Pathogenesis and Potential Therapeutic Strategies

With respect to structural and functional cardiac disorders, heart failure (HF) is divided into HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Oxidative stress contributes to the development of both HFrEF and HFpEF. Identification of a broad spectrum of reactive oxygen species (ROS)-induced pathways in preclinical models has provided new insights about the importance of ROS in HFrEF and HFpEF development. While current treatment strategies mostly concern neuroendocrine inhibition, recent data on ROS-induced metabolic pathways in cardiomyocytes may offer additional treatment strategies and targets for both of the HF forms. The purpose of this article is to summarize the results achieved in the fields of: (1) ROS importance in HFrEF and HFpEF pathophysiology, and (2) treatments for inhibiting ROS-induced pathways in HFrEF and HFpEF patients. ROS-producing pathways in cardiomyocytes, ROS-activated pathways in different HF forms, and treatment options to inhibit their action are also discussed.

Long-Acting Thioredoxin Ameliorates Doxorubicin-Induced Cardiomyopathy via Its Anti-Oxidative and Anti-Inflammatory Action

Although the number of patients with heart failure is increasing, a sufficient treatment agent has not been established. Oxidative stress and inflammation play important roles in the development of myocardial remodeling. When thioredoxin (Trx), an endogenous anti-oxidative and inflammatory modulator with a molecular weight of 12 kDa, is exogenously administered, it disappears rapidly from the blood circulation. In this study, we prepared a long-acting Trx, by fusing human Trx (HSA-Trx) with human serum albumin (HSA) and evaluated its efficacy in treating drug-induced heart failure. Drug-induced cardiomyopathy was created by intraperitoneally administering doxorubicin (Dox) to mice three times per week. A decrease in heart weight, increased myocardial fibrosis and markers for myocardial damage that were observed in the Dox group were suppressed by HSA-Trx administration. HSA-Trx also suppressed the expression of atrogin-1 and myostatin, myocardial atrophy factors in addition to suppressing oxidative stress and inflammation. In the Dox group, a decreased expression of endogenous Trx in cardiac tissue and an increased expression of macrophage migration inhibitory factor were observed, but these changes were restored to normal levels by HSA-Trx administration. These findings suggest that HSA-Trx improves the pathological condition associated with Dox-induced cardiomyopathy by its anti-oxidative/anti-inflammatory and myocardial atrophy inhibitory action.

microRNA-135a-5p regulates NOD-like receptor family pyrin domain containing 3 inflammasome-mediated hypertensive cardiac inflammation and fibrosis via thioredoxin-interacting protein

Hypertension is a severe public health problem that induces cardiac injury with alterations of gene expressions. The current study sought to evaluate the mechanism of microRNA(miR)-135a-5p in NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediation of cardiac inflammation and hypertensive cardiac fibrosis. Firstly, hypertensive mouse models were established using angiotensin II (Ang II), followed by miR-135a-5p agomir treatment. Subsequently, mouse blood pressure and basic cardiac function indexes, histopathological changes, and cardiac fibrosis were all determined, in addition to detection of factors related to inflammation and fibrosis. Additionally, mice cardiac fibroblasts (CFs) were isolated and treated with Ang II. The binding relationship of miR-135a-5p and thioredoxin-interacting protein (TXNIP) was predicted and testified, while the interaction of TXNIP and NLRP3 was detected by means of a co-immunoprecipitation assay. It was found that miR-135a-5p was poorly-expressed in Ang II-treated mice and further exerted cardioprotective effects against hypertensive heart diseases. Moreover, over-expression of miR-135a-5p resulted in inhibition of inflammatory infiltration and almost eliminated cardiac fibrosis, as evidenced by decreased Collagen (COL)-I, COL-III, a-smooth muscle actin, NLRP3, tumor necrosis factor-α, and interleukin-6. Mechanically, miR-135a-5p inhibited TXNIP expression to block the binding of TXNIP and NLRP3. On the other hand, TXNIP up-regulation reversed the protective role of miR-135a-5p over-expression in CFs. Collectively, our findings indicated that miR-135a-5p over-expression inhibited TXNIP expression to block the binding of TXNIP and NLRP3, thereby alleviating hypertensive cardiac inflammation and fibrosis.

Vidarabine, an anti-herpes agent, prevents occlusal-disharmony-induced cardiac dysfunction in mice

We recently reported a positive relationship between occlusal disharmony and cardiovascular disease via activation of β-adrenergic signaling in mice. Furthermore, inhibition of type 5 adenylyl cyclase (AC5), a major cardiac subtype in adults, protects the heart against oxidative stress. Here, we examined the role of AC5 in the development of occlusal-disharmony-induced cardiovascular disease in bite-opening (BO) mice, prepared by cementing a suitable appliance onto the mandibular incisor. We first examined the effects of BO treatment on cardiac function in mice treated or not treated for 2 weeks with vidarabine, which we previously identified as an inhibitor of cardiac AC. Cardiac function was significantly decreased in the BO group compared to the control group, but vidarabine ameliorated the dysfunction. Cardiac fibrosis, myocyte apoptosis and myocyte oxidative DNA damage were significantly increased in the BO group, but vidarabine blocked these changes. The BO-induced cardiac dysfunction was associated with increased phospholamban phosphorylation at threonine-17 and serine-16, as well as increased activation of the Ca2+-calmodulin-dependent protein kinase II/receptor-interacting protein 3 signaling pathway. These data suggest that AC5 inhibition with vidarabine might be a new therapeutic approach for the treatment of cardiovascular disease associated with occlusal disharmony.

Cardiomyocyte BRAF and type 1 RAF inhibitors promote cardiomyocyte and cardiac hypertrophy in mice in vivo

The extracellular signal-regulated kinase 1/2 (ERK1/2) cascade promotes cardiomyocyte hypertrophy and is cardioprotective, with the three RAF kinases forming a node for signal integration. Our aims were to determine if BRAF is relevant for human heart failure, whether BRAF promotes cardiomyocyte hypertrophy, and if Type 1 RAF inhibitors developed for cancer (that paradoxically activate ERK1/2 at low concentrations: the 'RAF paradox') may have the same effect. BRAF was up-regulated in heart samples from patients with heart failure compared with normal controls. We assessed the effects of activated BRAF in the heart using mice with tamoxifen-activated Cre for cardiomyocyte-specific knock-in of the activating V600E mutation into the endogenous gene. We used echocardiography to measure cardiac dimensions/function. Cardiomyocyte BRAFV600E induced cardiac hypertrophy within 10 d, resulting in increased ejection fraction and fractional shortening over 6 weeks. This was associated with increased cardiomyocyte size without significant fibrosis, consistent with compensated hypertrophy. The experimental Type 1 RAF inhibitor, SB590885, and/or encorafenib (a RAF inhibitor used clinically) increased ERK1/2 phosphorylation in cardiomyocytes, and promoted hypertrophy, consistent with a 'RAF paradox' effect. Both promoted cardiac hypertrophy in mouse hearts in vivo, with increased cardiomyocyte size and no overt fibrosis. In conclusion, BRAF potentially plays an important role in human failing hearts, activation of BRAF is sufficient to induce hypertrophy, and Type 1 RAF inhibitors promote hypertrophy via the 'RAF paradox'. Cardiac hypertrophy resulting from these interventions was not associated with pathological features, suggesting that Type 1 RAF inhibitors may be useful to boost cardiomyocyte function.

A Common Feature of Pesticides: Oxidative Stress-The Role of Oxidative Stress in Pesticide-Induced Toxicity

Pesticides are important chemicals or biological agents that deter or kill pests. The use of pesticides has continued to increase as it is still considered the most effective method to reduce pests and increase crop growth. However, pesticides have other consequences, including potential toxicity to humans and wildlife. Pesticides have been associated with increased risk of cardiovascular disease, cancer, and birth defects. Labels on pesticides also suggest limiting exposure to these hazardous chemicals. Based on experimental evidence, various types of pesticides all seem to have a common effect, the induction of oxidative stress in different cell types and animal models. Pesticide-induced oxidative stress is caused by both reactive oxygen species (ROS) and reactive nitrogen species (RNS), which are associated with several diseases including cancer, inflammation, and cardiovascular and neurodegenerative diseases. ROS and RNS can activate at least five independent signaling pathways including mitochondrial-induced apoptosis. Limited in vitro studies also suggest that exogenous antioxidants can reduce or prevent the deleterious effects of pesticides.

Suppression of SMOC2 alleviates myocardial fibrosis via the ILK/p38 pathway

Background

Fibrosis of the myocardium is one of the main pathological changes of adverse cardiac remodeling, which is associated with unsatisfactory outcomes in patients with heart disease. Further investigations into the precise molecular mechanisms of cardiac fibrosis are urgently required to seek alternative therapeutic strategies for individuals suffering from heart failure. SMOC2 has been shown to be essential to exert key pathophysiological roles in various physiological processes in vivo, possibly contributing to the pathogenesis of fibrosis. A study investigating the relationship between SMOC2 and myocardial fibrosis has yet to be conducted.

Methods

Mice received a continuous ISO injection subcutaneously to induce cardiac fibrosis, and down-regulation of SMOC2 was achieved by adeno-associated virus-9 (AAV9)-mediated shRNA knockdown. Neonatal fibroblasts were separated and cultured in vitro with TGFβ to trigger fibrosis and infected with either sh-SMOC2 or sh-RNA as a control. The role and mechanisms of SMOC2 in myocardial fibrosis were further examined and analyzed.

Results

SMOC2 knockdown partially reversed cardiac functional impairment and cardiac fibrosis in vivo after 21 consecutive days of ISO injection. We further demonstrated that targeting SMOC2 expression effectively slowed down the trans-differentiation and collagen deposition of cardiac fibroblasts stimulated by TGFβ. Mechanistically, targeting SMOC2 expression inhibited the induction of ILK and p38 in vivo and in vitro, and ILK overexpression increased p38 phosphorylation activity and compromised the protective effects of sh-SMOC2-mediated cardiac fibrosis.

Conclusion

Therapeutic SMOC2 silencing alleviated cardiac fibrosis through inhibition of the ILK/p38 signaling, providing a preventative and control strategy for cardiac remodeling management in clinical practice.

Structural Insights Support Targeting ASK1 Kinase for Therapeutic Interventions

Apoptosis signal-regulating kinase (ASK) 1, a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, modulates diverse responses to oxidative and endoplasmic reticulum (ER) stress and calcium influx. As a crucial cellular stress sensor, ASK1 activates c-Jun N-terminal kinases (JNKs) and p38 MAPKs. Their excessive and sustained activation leads to cell death, inflammation and fibrosis in various tissues and is implicated in the development of many neurological disorders, such as Alzheimer’s, Parkinson’s and Huntington disease and amyotrophic lateral sclerosis, in addition to cardiovascular diseases, diabetes and cancer. However, currently available inhibitors of JNK and p38 kinases either lack efficacy or have undesirable side effects. Therefore, targeted inhibition of their upstream activator, ASK1, stands out as a promising therapeutic strategy for treating such severe pathological conditions. This review summarizes recent structural findings on ASK1 regulation and its role in various diseases, highlighting prospects for ASK1 inhibition in the treatment of these pathologies.

Macrophage depletion protects against endothelial dysfunction and cardiac remodeling in angiotensin II hypertensive mice

Objective: Hypertension is associated with a low-grade systemic inflammation in cardiovascular system. Macrophage infiltration may initiate an inflammatory process that contributes to vascular and ventricular remodeling in hypertensive human and mice. The present study investigated the effect of chemical depletion of macrophage using liposome encapsulated clodronate (LEC) on cardiac hypertrophy and remodeling in angiotensin (Ang) II hypertensive mice.Methods: C57BL/6 mice received an Ang II (1.1 mg/kg/day with a minipump) infusion for 2 weeks to induce hypertension. Endothelium-dependent relaxation (ED) was examined by organ bath, hematoxylin and staining and Masson-Trichrome staining were used to evaluate aorta and cardiac hypertrophy and fibrosis.Results: Ang II infusion significantly increased systolic blood pressure (SBP), cardiac hypertrophy and fibrosis, and impaired EDR accompanied by increased macrophage infiltration in the heart. Treatment with LEC significantly lowered Ang II-induced cardiac hypertrophy and fibrosis and cardiac macrophage infiltration, and improved EDR with a mild reduction in SBP. Ang II increased the expression of inflammatory cytokines tumor necross factor alpha and interleukin 1 beta and profibrotic factors transforming growth factor beta 1 and fibronectin in the heart, with was reduced by LEC treatment. Treatment with LEC prevented Ang II-induced the phosphorphorylation of ERK1/2 and c-Jun-N-terminal kinase.Conclusions: Our study suggests that cardiac macrophage may be critical for hypertensive cardiac hypertrophy and remodeling, the underlying mechanisms may involve initial heart inflammation and the activation of hypertrophic MAPKs pathway.

Covid-19 and development of heart failure: mystery and truth

Coronavirus disease 2019 (Covid-19) is a novel worldwide pandemic caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). During Covid-19 pandemic, socioeconomic deprivation, social isolation, and reduced physical activities may induce heart failure (HF), destabilization, and cause more complications. HF appears as a potential hazard due to SARS-CoV-2 infection, chiefly in elderly patients with underlying comorbidities. In reality, the expression of cardiac ACE2 is implicated as a target point for SARS-CoV-2-induced acute cardiac injury. In SARS-CoV-2 infection, like other febrile illnesses, high blood viscosity, exaggerated pro-inflammatory response, multisystem inflammatory syndrome, and endothelial dysfunction-induced coagulation disorders may increase risk of HF development. Hypoxic respiratory failure, as in pulmonary edema, severe acute lung injury (ALI), and acute respiratory distress syndrome (ARDS) may affect heart hemodynamic stability due to the development of pulmonary hypertension. Indeed, Covid-19-induced HF could be through the development of cytokine storm, characterized by high proliferation pro-inflammatory cytokines. In cytokine storm-mediated cardiac dysfunction, there is a positive correlation between levels of pro-inflammatory cytokine and myocarditis-induced acute cardiac injury biomarkers. Therefore, Covid-19-induced HF is more complex and related from a molecular background in releasing pro-inflammatory cytokines to the neuro-metabolic derangements that together affect cardiomyocyte functions and development of HF. Anti-heart failure medications, mainly digoxin and carvedilol, have potent anti-SARS-CoV-2 and anti-inflammatory properties that may mitigate Covid-19 severity and development of HF. In conclusion, SARS-CoV-2 infection may lead to the development of HF due to direct acute cardiac injury or through the development of cytokine storms, which depress cardiomyocyte function and cardiac contractility. Anti-heart failure drugs, mainly digoxin and carvedilol, may attenuate severity of HF by reducing the infectivity of SARS-CoV-2 and prevent the development of cytokine storms in severely affected Covid-19 patients.

MicroRNA-23a-5p Is Involved in the Regulation of Lipopolysaccharide-Induced Acute Lung Injury by Targeting HSP20/ASK1

Inflammation and oxidative stress contribute to the progression of acute lung injury (ALI). MicroRNA-23a-5p (miR-23a-5p) has been reported to regulate inflammation and oxidative stress; however, its role in ALI is still poorly elucidated. Mice were intravenously treated with the miR-23a-5p antagomir, agomir, or the negative controls for 3 consecutive days and then received a single intratracheal injection of lipopolysaccharide (LPS, 5 mg/kg) to induce ALI. Pulmonary function, bronchoalveolar lavage fluids (BALFs), arterial blood gas, and molecular biomarkers associated with inflammation and oxidative stress were analyzed. In addition, murine peritoneal macrophages were isolated and treated with LPS to verify the role of miR-23a-5p in vitro. We detected an elevation of miR-23a-5p expression in the lungs from ALI mice. The miR-23a-5p antagomir was prevented, whereas the miR-23a-5p agomir aggravated inflammation, oxidative stress, lung tissue injury, and pulmonary dysfunction in LPS-treated mice. Besides, the miR-23a-5p antagomir also reduced the productions of proinflammatory cytokines and free radicals in LPS-treated primary macrophages, which were further augmented in cells following the miR-23a-5p agomir treatment. Additional findings demonstrated that the miR-23a-5p agomir exacerbated LPS-induced ALI via activating apoptosis signal-regulating kinase 1 (ASK1), and that pharmacological or genetic inhibition of ASK1 significantly repressed the deleterious effects of the miR-23a-5p agomir. Moreover, we proved that the miR-23a-5p agomir activated ASK1 via directly reducing heat shock protein 20 (HSP20) expression. miR-23a-5p is involved in the regulation of LPS-induced inflammation, oxidative stress, lung tissue injury, and pulmonary dysfunction by targeting HSP20/ASK1, and it is a valuable therapeutic candidate for the treatment of ALI.

Apocynin attenuates diabetic cardiomyopathy by suppressing ASK1-p38/JNK signaling

Diabetic cardiomyopathy (DCM) significantly increased the morbidity of heart failure in diabetic patients. Long-time oxidative stress is an indisputable contributor for DCM development. Apocynin (APO) has been suggested to be a potential drug against oxidative stress. The study aims to find out the effects of APO on DCM and the related mechanisms. Mice were randomly divided into four groups: control (CON), APO, DCM and DCM + APO. Echocardiography analyses, histological analyses, Western blot and RT-PCR were used to explore the roles and mechanisms of APO in DCM. Isolated neonatal rat cardiomyocytes (NRCMs) and cardiac fibroblasts (CFs) were used for further confirming the APO treatment effects in vitro. Deteriorated cardiac function, enlarged cardiomyocytes, excess cardiac fibrosis and significant cardiac oxidative stress were observed in DCM group. However, APO treatment successfully improved cardiac function, decreased cardiac hypertrophy and fibrosis, and depressed oxidative stress. Mechanistically, APO treatment markedly suppressed apoptosis signal regulating kinase 1(ASK1)-p38/c-jun N-terminal kinase (JNK) signaling and reduced apoptosis. It also inhibited NRCM apoptosis and CF activation via depressing ASK1-p38/JNK signaling in vitro. Moreover, adenovirus-mediated ASK1 overexpression completely removed the protection of APO in vitro. In conclusion, APO treatment could effectively attenuate DCM-associated injuries in vivo and protect against high glucose-induced NRCM and CF injuries in vitro via suppressing ASK1-p38/JNK signaling. APO might be a potential ASK1 inhibitor for treating DCM.

Redox signaling in heart failure and therapeutic implications

Heart failure is a growing health burden worldwide characterized by alterations in excitation-contraction coupling, cardiac energetic deficit and oxidative stress. While current treatments are mostly limited to antagonization of neuroendocrine activation, more recent data suggest that also targeting metabolism may provide substantial prognostic benefit. However, although in a broad spectrum of preclinical models, oxidative stress plays a causal role for the development and progression of heart failure, no treatment that targets reactive oxygen species (ROS) directly has entered the clinical arena yet. In the heart, ROS derive from various sources, such as NADPH oxidases, xanthine oxidase, uncoupled nitric oxide synthase and mitochondria. While mitochondria are the primary source of ROS in the heart, communication between different ROS sources may be relevant for physiological signalling events as well as pathologically elevated ROS that deteriorate excitation-contraction coupling, induce hypertrophy and/or trigger cell death. Here, we review the sources of ROS in the heart, the modes of pathological activation of ROS formation as well as therapeutic approaches that may target ROS specifically in mitochondria.