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Macrophage-derived foam cells play a crucial role in plaque formation and rupture during the progression of atherosclerosis. Traditional studies have often overlooked the heterogeneity of foam cells, focusing instead on populations of cells. To address this, we have developed time-resolved, single-cell metabolomics and lipidomics approaches to explore the heterogeneity of macrophages during foam cell formation. Our dynamic metabolomic and lipidomic analyses revealed a dual regulatory axis involving inflammation and ferroptosis. Further, single-cell metabolomics and lipidomics have delineated a continuum of macrophage states, with varied susceptibilities to apoptosis and ferroptosis. Single-cell transcriptomic profiling confirmed these divergent fates, both in established cell lines and in macrophages derived from peripheral blood monocytes. This research has uncovered the complex molecular interactions that dictate these divergent cell fates, providing crucial insights into the pathogenesis of atherosclerosis.

Cardiac remodeling is a critical process following myocardial infarction (MI), potentially leading to heart failure if untreated. The significance of mitochondrial homeostasis in MI remains insufficiently understood. Samm50 is an essential component of mitochondria. Our study aimed to investigate its role in hypoxia-induced cardiac injury and the underlying mechanisms. First, we observed that Samm50 was dynamically downregulated in mice with MI compared to the control mice. In vitro, Samm50 was also downregulated in oxygen-glucose-deprived neonatal rat cardiomyocytes and fibroblasts. Overexpression and knockdown of Samm50 mitigated and exacerbated cardiac apoptosis and fibrosis, while also improving and worsening mitochondrial homeostasis, respectively. Protein interactions with Samm50 during the protective process were identified via immune-coprecipitation/mass spectroscopy. Mechanistically, serine hydroxymethyltransferase 2 (Shmt2) interacted with Samm50, acting as a crucial element in the protective process by hindering the transfer of Bax from the cytoplasm to the mitochondria and subsequent activation of caspase-3. Inhibition of Shmt2 diminished the protective effect of Samm50 overexpression against cardiac injury. Finally, Samm50 overexpression in vivo mitigated cardiac remodeling and enhanced cardiac function in both acute and chronic MI. In conclusion, Samm50 overexpression mitigated hypoxia-induced cardiac remodeling by inhibiting apoptosis and fibrosis, with Shmt2 acting as a key regulator in this protective process. The Samm50/Shmt2 axis represents a newly discovered mitochondria-related pathway for mitigating hypoxia-induced cardiac injury., Competing Interests: Declaration of competing interest The authors declared that they have no conflict of interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Histamine is a widely distributed biogenic amine involved in the regulation of an array of biological processes. Serum histamine level is markedly elevated in the early stages of acute myocardial infarction, whereas the role it plays remains unclear. Histidine decarboxylase (HDC) is the unique enzyme responsible for histamine production, and cardiac injury is significantly aggravated in HDC knockout mice (HDC -/- ), in which histamine is deficient. We also observed that autophagy was highly activated in cardiomyocytes of HDC -/- mice post acute myocardial infarction (AMI), which was abolished by compensation of exogenous histamine. The in vivo and in vitro results showed that acting through histamine 1 receptor, histamine increased miR-206 and miR-216b, which worked in concert to target to Atg13, resulting in the reduction of autophagy activation under hypoxia and AMI condition. Further study revealed that Atg13 interacted with FADD to promote the activation of caspase-8 and cell apoptosis. Taken together, these data unveil a novel intracellular signaling pathway involved in histamine regulating myocardial autophagy and apoptosis under hypoxia and AMI condition, which might help to more comprehensively evaluate the usage of histamine receptor antagonists and to develop new therapeutic targets for myocardial infarction.

Previous studies evidenced the beneficial effects of low-to-moderate alcohol consumption on cardiovascular system by activation of mitochondrial aldehyde dehydrogenase 2 (ALDH2), a key enzyme metabolizing acetaldehyde to innocuous acetic acid, in diabetic mice. It remains questionable whether people with inactive ALDH2 would also benefit from the drinking habit. Present study was therefore designed to examine the influence of ALDH2 deficiency on low-to-moderate alcohol consumption related myocardial alternations. Wildtype (WT) and ALDH2 knockout (KO) mice were exposed to low-to-moderate alcohol (EtOH) challenge for 6weeks. Cardiac function and cell death related pathways were then measured. Although EtOH exposure did not further improve cardiac function or reduce reactive oxygen species (ROS) levels in WT mice, levels of high density lipoprotein-cholesterol (HDL-c) and expression of heme oxygenase-1 (HO-1) were significantly elevated in WT-EtOH group. However, EtOH exposure in KO mice depressed cardiac function as indicated by reduced left ventricular ejection fraction (EF) and increased myocardial fibrosis deposition as well as the excessive ROS accumulation. Above changes were related to altered cell demise (apoptosis and necroptosis), as shown by upregulated expression of cleaved caspase 9, cleaved caspase 3 and RIP1/RIP3/MLKL cascade. Our results thus suggest that ALDH2 is indispensable for the favorable cardiac effect of low-to-moderate alcohol consumption and ALDH2 deficiency may lead to unexpected cardiac dysfunctions via enhancing myocardial apoptosis and necroptosis., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background: Here, we determined miR-499 involvement in the protective effect of ischemic postconditioning (IPC) against myocardial ischemia/reperfusion (I/R) injury and identified the underlying mechanisms., Methods: To investigate the cardioprotective effect of IPC-induced miR-499, rats were divided into the following five groups: sham, I/R, IPC, IPC + scramble, and IPC + antagomiR-499. Hemodynamic indexes were measured by carotid-artery intubation to assess left ventricular function . Ischemia and infarction areas of rat hearts were determined by Evans blue and triphenyltetrazolium chloride staining, and cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end-labeling assay., Results: IPC attenuated I/R-induced infarct size of the left ventricle (45.28 ± 5.40% vs. 23.56 ± 6.20%, P < 0.05), myocardial apoptosis, and decreased creatine kinase (1867.31 ± 242.41% vs. 990.21 ± 172.39%, P < 0.05), lactate dehydrogenase (2257.50 ± 305.11% vs. 1289.11 ± 347.28%, P < 0.05), and malondialdehyde levels (7.18 ± 1.63% vs. 4.85 ± 1.52%, P < 0.05). Additionally, left ventricular systolic pressure, +dp/dtmax, and -dp/dtmax were elevated, and left ventricular end diastolic pressure was significantly reduced in the IPC group. Furthermore, IPC-mediated cardiac protection against I/R injury was inhibited in vivo and in vitro by knockdown of cardiac miR-499, suggesting that miR-499 may participate in the protective function of IPC against I/R injury through targeting programmed cell death 4 (PDCD4)., Conclusion: Our data revealed that IPC-regulated miR-499 plays an important role in IPC-mediated cardiac protection against I/R injury by targeting PDCD4., (© 2016 The Author(s) Published by S. Karger AG, Basel.)

Histamine is a biogenic amine that is widely distributed and has multiple functions, but the role it plays in acute myocardial infarction (AMI) remains unclear. In this study, we investigated the origin and contribution of endogenous histamine to AMI. Histidine decarboxylase (HDC) is the unique enzyme responsible for histamine generation. Using HDC-EGFP bacterial artificial chromosome (BAC) transgenic mice in which EGFP expression is controlled by the HDC promoter, we identified HDC expression primarily in CD11b(+)Gr-1(+) immature myeloid cells (IMCs) that markedly increase in the early stages of AMI. Deficiency of histamine in HDC knockout mice (HDC(-/-)) reduced cardiac function and exacerbated the injury of infarcted heart. Furthermore, administering either an H1 receptor antagonist (pyrilamine) or an H2 receptor antagonist (cimetidine) demonstrated a protective effect of histamine against myocardial injury. The results of in vivo and in vitro assays showed that histamine deficiency promotes the apoptosis of cardiomyocytes and inhibits macrophage infiltration. In conclusion, CD11b(+)Gr-1(+) IMCs are the predominant HDC-expressing sites in AMI, and histamine plays a protective role in the process of AMI through inhibition of cardiomyocyte apoptosis and facilitation of macrophage infiltration.

Lenalidomide (Revlimid; Selleck Chemicals, Houston, TX, USA), an analogue of thalidomide, possesses potent cytokine modulatory capacity through inhibition of cytokines such as tumour necrosis factor (TNF)-α, a cytokine pivotal for the onset and development of complications in obesity and diabetes mellitus. The present study was designed to evaluate the effect of lenalidomide on oxidative stress, protein and DNA damage in multiple organs in an ob/ob murine model of obesity. To this end, C57BL/6 lean and ob/ob obese mice were administered lenalidomide (50 mg/kg per day, p.o.) for 5 days. Oxidative stress, protein and DNA damage were assessed using the conversion of reduced glutathione (GSH) to oxidized glutathione (GSSG), carbonyl formation and Comet assay, respectively. Apoptosis was evaluated using caspase 3 activity, and levels of Bax, Bcl-2, Bip, caspase 8, caspase 9 and TNF-α were assessed using western blot analysis. Lenalidomide treatment did not affect glucose clearance in lean or ob/ob mice. Obese mice exhibited a reduced GSH/GSSG ratio in the liver, gastrocnemius skeletal muscle and small intestine, as well as enhanced protein carbonyl formation, DNA damage and caspase 3 activity in the liver, kidney, skeletal muscle and intestine; these effects were alleviated by lenalidomide, with the exception of obesity-associated DNA damage in the liver and kidney. Western blot analysis revealed elevated TNF-α, Bax, Bcl-2, Bip, caspase 8 and caspase 9 in ob/ob mice with various degrees of reversal by lenalidomide treatment. Together, these data indicate that lenalidomide protects against obesity-induced tissue injury and protein damage, possibly in association with antagonism of cytokine production and cytokine-induced apoptosis and oxidative stress., (© 2014 Wiley Publishing Asia Pty Ltd.)

Calpain is a family of neutral cysteine proteinase involved in many physiological and pathological processes including virus replication, autophagy and apoptosis. Previous study has indicated the involvement of calpain in pathogenesis of coxsackievirus B3 (CVB3)-induced myocarditis. Besides, many studies demonstrated that host cell autophagy and apoptosis mechanisms participate in virus life cycle. However, role of calpain in CVB3 replication via autophagy/apoptosis mechanisms has not been reported, which was discussed here in H9c2 cardiomyocytes. The data demonstrated that calpain was activated following CVB3 infection. Calpain inhibition decreased autophagy, indicating role of calpain in enhancing autophagy during CVB3 infection. Both calpain activity and autophagy were involved in facilitating CVB3 replication demonstrated by virus titer and CVB3 capsid protein VP1 expression alterations resulting from calpain inhibitor ALLN and autophagy inhibitor 3MA intervention. We also found that both calpain activity and autophagy suppressed caspase3 activity and host cell apoptosis 5-10h post-infection (p.i.). In summary, the present study shows that CVB3 infection of H9c2 cells hinders caspase3 activity provocation and cell apoptosis at least in the early phase of infection (5-10h p.i.) via calpain-induced autophagy enhancement, which might be a mechanism facilitating CVB3 replication in host cells., (Copyright © 2013 Elsevier B.V. All rights reserved.)

MicroRNA-34a (miR-34a) promotes apoptosis via down-regulating many anti-apoptotic proteins. Aldehyde dehydrogenase 2 (ALDH2) is an anti-apoptotic enzyme whose activity decline associates with myocardial injury. We tested hypothesis that miR-34a might play a pro-apoptotic role in myocardial infarction (MI) by down-regulating ALDH2. MiR-34a was highly increased while ALDH2 expression was decreased after experimental MI. Overexpression of miR-34a in neonatal rat cardiomyocyte could significantly enhance apoptosis and down-regulate ALDH2 expression. In 293 cells, luciferase reporter assay results demonstrated that ALDH2 was a direct target of miR-34a. Serum miR-34a levels in acute myocardial infarction (AMI) patients and rats were significantly higher than healthy subjects and sham rats. Our results proved that miR-34a could promote cardiomyocyte apoptosis via negatively regulating ALDH2 and circulating miR-34a was increased in the condition of MI. Thus, miR-34a may constitute a new therapeutic target and diagnostic marker for patients with MI.

The therapeutic effect of transplantation of mesenchymal stem cells (MSCs) in myocardial infarction (MI) appears to be limited by poor cell viability in the injured tissue, which is a consequence of oxidative stress and pro-apoptotic factors. High density lipoprotein (HDL) reverses cholesterol transport and has anti-oxidative and anti-apoptotic properties. We, therefore, investigated whether HDL could protect MSCs from oxidative stress-induced apoptosis. MSCs derived from the bone marrow of rats were pre-incubated with or without HDL, and then were exposed to hydrogen peroxide (H(2)O(2)) in vitro, or were transplanted into experimentally infarcted hearts of rats in vivo. Pre-incubation of MSCs with HDL increased cell viability, reduced apoptotic indices and resulted in parallel decreases in reactive oxygen species (ROS) in comparison with control MSCs. Each of the beneficial effects of HDL on MSCs was attenuated by inhibiting the PI3K/Akt pathway. Preconditioning with HDL resulted in higher MSC survival rates, improved cardiac remodeling and better myocardial function than in the MSC control group. Collectively, these results suggest that HDL may protect against H(2)O(2)-induced apoptosis in MSCs through activation of a PI3K/Akt pathway, and by suppressing the production of ROS.

Aldehyde dehydrogenase 2 (ALDH2), a mitochondrial-specific enzyme, has been proved to be involved in oxidative stress-induced cell apoptosis, while little is known in cardiomyocytes. This study was aimed at investigating the role of ALDH2 in antimycin A-induced cardiomyocytes apoptosis by suppressing ALDH2 activity with a specific ALDH2 inhibitor Daidzin. Antimycin A (40μg/ml) was used to induce neonatal cardiomyocytes apoptosis. Daidzin (60μM) effectively inhibited ALDH2 activity by 50% without own effect on cell apoptosis, and significantly enhanced antimycin A-induced cardiomyocytes apoptosis from 33.5±4.4 to 56.5±6.4% (Hochest method, p<0.05), and from 57.9±1.9 to 74.0±11.9% (FACS, p<0.05). Phosphorylation of activated MAPK signaling pathway, including extracellular signal-regulated kinase (ERK1/2), c-Jun NH2-terminal kinase (JNK) and p38 was also increased in antimycin A and daidzin treated cardiomyocytes compared to the cells treated with antimycin A alone. These findings indicated that modifying mitochondrial ALDH2 activity/expression might be a potential therapeutic option on reducing oxidative insults induced cardiomyocytes apoptosis., (Copyright © 2009 Elsevier Masson SAS. All rights reserved.)

Heat shock transcription factor-1 (HSF1) protects against cardiac diseases such as ischemia/reperfusion injury and myocardial infarction. However, the mechanisms have not yet been fully characterized. In this study, we investigated the effects of reactive oxygen species (ROS) and apoptosis signal-regulating kinase-1 (ASK1) in HSF1-regulated cardiomyocyte protection. Cultured cardiomyocytes of neonatal rats were transfected with HSF1, ASK1 or both of them before exposure to H(2)O(2), and the ROS generation, c-Jun N-terminal kinase (JNK) activity and apoptosis were examined. H(2)O(2) significantly increased intracellular ROS generation and apoptotic cells as expected, and all these cellular events were greatly inhibited by overexpression of HSF1. However, H(2)O(2)-induced increases in JNK phosphorylation and cell apoptosis were largely enhanced by ASK1 overexpression whereas the similar transfection did not affect the ROS generation in the cells. Moreover, inhibition of H(2)O(2)-increased ROS generation, JNK phosphorylation, and cellular apoptosis by overexpression of HSF1 tended to be disappeared, when the cells were co-transfected with ASK1. These results suggest that HSF1 protects cardiomyocytes from apoptosis under oxidative stress via down-regulation of intracellular ROS generation and inhibition of JNK phosphorylation. Although ASK1 itself has no effect on intracellular ROS generation, it may affect the inhibitory effects of HSF1 on ROS generation, JNK activity, and cardiomyocyte injury.

Percutaneous coronary intervention is the main therapy for revascularization of occluded coronary arteries. However, a progressive artery restenosis caused by abnormal proliferation and migration of vascular smooth muscle cells (VSMC) hinders the effective treatment. In this study, we examined the effect of emodin, a natural anthraquinoid compound, on cultured VSMC. Lower doses of emodin suppressed cell proliferation and induced unscheduled DNA synthesis. Higher doses of emodin increased lumpy chromatin condensation and lysosomes in VSMC, suggesting the occurrence of apoptosis and autophagy. Emodin increased production of reactive oxygen species (ROS), which was abolished by an NADPH oxidase inhibitor diphenylene iodonium (DPI). DPI could also decrease the number of apoptosis induced by emodin, suggesting the involvement of ROS in emodin-induced apoptosis. Emodin upregulated the protein levels of p53 in a dose-dependent manner. Laser confocal microscope showed most of emodin scattering in the cytoplasms and a little within the nuclei. These findings collectively indicated that emodin induces both growth arrest and death of human VSMCs in 2 independent manners, implying it as a promising therapy for preventing restenosis.

Objective: Adipose‐derived mesenchymal stem cells (ADSCs) offer great promise as cell therapy for ischaemic diseases. Due to their poor survival in the ischaemic environment, the therapeutic efficacy of ADSCs is still relatively low. Interleukin‐11 (IL‐11) has been shown to play a key role in promoting cell proliferation and protecting cells from oxidative stress injury. The aim of this study was to determine whether IL‐11 could improve therapeutic efficacy of ADSCs in ischaemic diseases. Methods and Results: ADSCs were prepared from inguinal subcutaneous adipose tissue and exposed to hypoxic environment. The protein expression of IL‐11 was decreased after hypoxic treatment. In addition, ADSCs viability was increased after IL‐11 treatment under hypoxia. Moreover, IL‐11 enhanced ADSCs viability in a dose‐dependent manner under normoxia. Importantly, IL‐11 promoted ADSCs proliferation and migration and protected ADSCs against hydrogen peroxide‐induced cellular death. Notably, IL‐11 enhanced ADSCs proliferation and migration, also promoted cell survival and apoptosis resistance by STAT3 signalling. In vivo, mice were subjected to limb ischaemia and treated with IL‐11 overexpression ADSCs and control ADSCs. IL‐11 overexpression ADSCs improved perfusion recovery in the ischaemic muscles. Conclusions: We provide the evidence that IL‐11 promoted ADSCs proliferation, stimulated ADSCs migration and attenuated ADSCs apoptosis by activation of STAT3 signalling. These results suggest that IL‐11 facilitated ADSCs engraftment in ischaemic tissue, thereby enhanced ADSCs therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Fingolimod (FTY720) after phosphorylation, as the ligand of sphingosine 1‐phosphate receptors (S1PRs), plays an important role in cell proliferation and differentiation. In this article, FTY720 in the treatment of coxsackievirus B3 (CVB3)‐induced viral myocarditis was closely related to apoptosis and AKT/caspase‐3 apoptotic pathways. We found that CVB3 inhibited myocardial apoptosis at the early stage with upregulating p‐AKT level and downregulating activated caspase‐3 level for replication of virus progeny, whereas it promoted apoptosis at a late stage with downregulating p‐AKT and upregulating activated caspase‐3 for releasing the newly synthesized virus to spread. Interestingly, FTY720 could reverse this trend; it promoted apoptosis at an early stage and inhibited apoptosis at the late stage in vivo and vitro, which proved the antiviral effect. We also found that S1PR1, S1PR4, and S1PR5, rather than S1PR2 and S1PR3, were regulated by FTY720 in this process. The results confirmed that FTY720 alleviates CVB3‐induced myocarditis and inhibits viral replication through regulating S1PRs and AKT/caspase‐3 pathways with a bidirectional regulation of apoptosis. [ABSTRACT FROM AUTHOR]

The immune inflammatory response plays a crucial role in many cardiac pathophysiological processes, including ischaemic cardiac injury and the post-infarction repair process. Micro RNAs (mi RNAs) regulate the development and function of dendritic cells ( DCs), which are key players in the initiation and regulation of immune responses; however, the underlying regulatory mechanisms remain unclear. Here, we used the supernatants of necrotic primary cardiomyocytes (Necrotic-S) to mimic the myocardial infarction ( MI) microenvironment to investigate the role of mi RNAs in the regulation of DC-mediated inflammatory responses. Our results showed that Necrotic-S up-regulated the DC maturation markers CD40, CD83 and CD86 and increased the production of inflammatory cytokines, concomitant with the up-regulation of miR-181a and down-regulation of miR-150. Necrotic-S stimulation activated the JAK/ STAT pathway and promoted the nuclear translocation of c-Fos and NF-κB p65, and silencing of STAT1 or c-Fos suppressed Necrotic-S-induced DC maturation and inflammatory cytokine production. The effects of Necrotic-S on DC maturation and inflammatory responses, its activation of the JAK/ STAT pathway and the induction of cardiomyocyte apoptosis under conditions of hypoxia were suppressed by miR-181a or miR-150 overexpression. Taken together, these data indicate that miR-181a and miR-150 attenuate DC immune inflammatory responses via JAK1- STAT1/c-Fos signalling and protect cardiomyocytes from cell death under conditions of hypoxia. [ABSTRACT FROM AUTHOR]

Background/Aims: To investigate whether nucleosome assembly protein 1-like 1 (Nap1l1) regulates the proliferation of induced pluripotent stem cells (iPSC) and the potential mechanisms. Methods: Nap1l1-knockdown-iPSC and Nap1l1-overexpression-iPSC were constructed by transfection of lentiviral particles. The proliferation of iPSC was detected by MTT analysis, and cell cycle was analyzed by flow cytometry. Results: Nap1l1 overexpression promoted iPSC proliferation and induced G2/M transition compared to their control iPSC while Nap1l1-knockdown-iPSC dramatically displayed the reduced proliferation and accumulated G2/M phase cells. Further analysis showed that Nap1l1 overexpression in iPSC increased the expression of cyclin B1, downregulated the expression of p21 and p27, while knockdown of Nap1l1 showed the opposite effects. In addition, overexpression of Nap1l1 promoted the phosphorylation of AKT and ERK in iPSC, while knockdown of Nap1l1 inhibited the effects. However, these effects displayed in Nap1l1-overexpression-iPSC were greatly suppressed by the inhibition of AKT or ERK signaling. Conclusions: The results indicate that Nap1l1 promotes the proliferation of iPSC attributable to G2/M transition caused by downregulation of p27 and p21, and upregulation of cyclin B1, the activation of AKT or ERK is involved in the process. The present study has revealed a novel molecular mechanism involved in the proliferation of iPSC. © 2016 The Author(s) Published by S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Programmed cell death 5 (PDCD5) is a tumor suppressor gene that regulates the cell cycle, apoptosis and immune responses. However, the physiological function of Pdcd5 in cardiac aging remains unknown. We find that Pdcd5 mRNA and protein levels were significantly increased in the heart of mice with age. Therefore, we hypothesize that Pdcd5 regulates cardiac aging. To test the hypothesis, we generated muscle-specific Pdcd5 -deficient mice. Mature adult Pdcd5 -deficient mice had normal cardiac morphology and function. In naturally aged mice, Pdcd5 deficiency alleviated age-related cardiac phenotypes including reduced fibrosis and suppressed cardiomyocyte hypertrophy. Moreover, muscle-specific Pdcd5 deficiency attenuated cellular senescence in the heart as demonstrated by decreased number of senescence-associated β-galactosidase-positive cells, diminished p53, p21 and p16 expression, and reduced the senescence-associated secretory phenotype. Apoptotic cell death was reduced by Pdcd5 deficiency in the heart as revealed by terminal deoxynucleotidyl transferase dUTP nick end labeling assay, which was coincident with diminished Bcl-2-associated X protein, and enhanced B-cell lymphoma 2 and X-linked inhibitor of apoptosis protein expression. Mitochondrial quality in cardiomyocytes was improved by Pdcd5 deficiency through increased Parkin-mediated mitophagy. In addition, Pdcd5 deficiency alleviated doxorubicin-induced premature cellular senescence and cardiac aging. Furthermore, Pdcd5 protein abundance was significantly correlated with p53 protein abundance, and Pdcd5 interacted with p53 in the heart. Taken together, our results reveal that Pdcd5 deficiency attenuates cardiac aging by reducing cellular senescence and apoptosis, and increasing Parkin-mediated mitophagy, likely through p53. Pdcd5 is a novel regulator of cardiac aging and a potential therapeutic target. • Muscle-specific Pdcd5 deficiency attenuates natural cardiac aging and doxorubicin-induced premature cardiac aging. • Pdcd5 deficiency reduces cellular senescence and apoptosis, and increases Parkin-mediated mitophagy in aged heart. • Pdcd5 protein abundance is significantly correlated with p53 protein abundance, and Pdcd5 interacts with p53 in the heart. [ABSTRACT FROM AUTHOR]

Heat shock transcription factor 1 (HSF1) deficiency aggravates cardiac remodeling under pressure overload. However, the mechanism is still unknown. Here we employed microRNA array analysis of the heart tissue of HSF1-knockout (KO) mice to investigate the potential roles of microRNAs in pressure overload-induced cardiac remodeling under HSF-1 deficiency, and the profiles of 478 microRNAs expressed in the heart tissues of adult HSF1-KO mice were determined. We found that the expression of 5 microRNAs was over 2-fold higher expressed in heart tissues of HSF1-KO mice than in those of wild-type (WT) control mice. Of the overexpressed microRNAs, miR-195a-3p had the highest expression level in HSF1-null endothelial cells (ECs). Induction with miR-195a-3p in ECs significantly suppressed CD31 and VEGF, promoted AngII-induced EC apoptosis, and impaired capillary-like tube formation. In vivo, the upregulation of miR-195a-3p accentuated cardiac hypertrophy, increased the expression of β-MHC and ANP, and compromised systolic function in mice under pressure overload induced by transverse aortic constriction (TAC). By contrast, antagonism of miR-195a-3p had the opposite effect on HSF1-KO mice. Further experiments confirmed that AMPKα2 was the direct target of miR-195a-3p. AMPKα2 overexpression rescued the reduction of eNOS and VEGF, and the impairment of angiogenesis that was induced by miR-195a-3p. In addition, upregulation of AMPKα2 in the myocardium of HSF1-null mice by adenovirus-mediated gene delivery enhanced CD31, eNOS and VEGF, reduced β-MHC and ANP, alleviated pressure overload-mediated cardiac hypertrophy and restored cardiac function. Our findings revealed that the upregulation of miR-195a-3p due to HSF1 deficiency impaired cardiac angiogenesis by regulating AMPKα2/VEGF signaling, which disrupted the coordination between the myocardial blood supply and the adaptive hypertrophic response and accelerated the transition from cardiac hypertrophy to heart failure in response to pressure overload. [ABSTRACT FROM AUTHOR]

Aims LCZ696, a novel angiotensin receptor neprilysin inhibitor, is effective in treating heart failure patients. Doxorubicin (DOX) is an effective antitumor medication but the cardiotoxicity limited its clinical use. In this study, we aimed to determine the effect of LCZ696 on DOX-induced cardiomyopathy in mice and in vitro and to explore related mechanisms focusing on fission protein dynamin-related protein 1 (Drp1). Methods and results In human study, we found that myocardial fission protein Drp1 expression and its ser 616 phosphorylation were significantly increased in dilated cardiomyopathy (DCM) patients. Male Balb/c mice and H9c2 cardiomyocytes were randomized into three groups: saline, DOX, DOX plus LCZ696. Reduced cardiac function, mitochondrial morphology disturbance, reduced activity of mitochondrial respiration complex I and lowered adenosine triphosphate (ATP) content were detected post DOX stimulation in mice, which could be significantly improved by LCZ696. Fission protein Drp1 and its ser 616 phosphorylation were also increased post DOX and which could be reduced by LCZ696. In vitro, increased cardiomyocyte apoptosis, Drp1 ser 616 phosphorylation post DOX stimulation could be significantly attenuated by LCZ696 or Drp1 specific inhibitor Midivi-1. Furthermore, over-expression of Drp1 abrogated the protection effect of LCZ696 against DOX-induced cardiotoxicity in H9c2 cells. Conclusion The protective effect of LCZ696 against DOX-induced cardiac dysfunction is at least partly associated with alleviating Drp1-mediated mitochondrial dysfunction. [ABSTRACT FROM AUTHOR]

Abstract: We examined whether granulocyte colony-stimulating factor (G-CSF) prevents cardiac dysfunction and remodeling after myocardial infarction (MI) in large animals. MI was produced by ligation of left anterior descending coronary artery in swine. G-CSF (10μg/kg/day, once a day) was injected subcutaneously from 24h after ligation for 7 days. Echocardiographic examination revealed that the G-CSF treatment induced improvement of cardiac function and attenuation of cardiac remodeling at 4 weeks after MI. In the ischemic region, the number of apoptotic endothelial cells was smaller and the number of vessels was larger in the G-CSF treatment group than in control group. Moreover, vascular endothelial growth factor was more abundantly expressed and Akt was more strongly activated in the ischemic region of the G-CSF treatment group than of control group. These findings suggest that G-CSF prevents cardiac dysfunction and remodeling after MI in large animals. [Copyright &y& Elsevier]

A homeobox-containing transcription factor Csx/Nkx2–5 is an important regulator of cardiac development. Many different human CSX/NKX2–5 mutations have been reported to cause congenital heart disease. We here examined the effects of three representative CSX/NKX2–5 mutations on cardiomyocyte differentiation and death with the use of the P19CL6 cardiomyogenic cell lines. Stable overexpression of wild-type CSX/NKX2–5 enhanced expression of cardiac-specific genes such as MEF2C and MLC2v, the promoter activity of the atrial natriuretic peptide gene, and the terminal differentiation of P19CL6 into cardiomyocytes, while all CSX/NKX2–5 mutants attenuated them by different degrees. When exposed to H2O2 or cultured without change of the medium, many differentiated P19CL6 cells overexpressing the mutants, especially the mutant which lacks the carboxyl terminal region just after the homeodomain, were dead, while most of the cells overexpressing wild-type CSX/NKX2–5 survived. Overexpression of the carboxyl terminus-deleted mutant down-regulated expression of an anti-apoptotic protein Bcl-xL and up-regulated that of a pro-apoptotic protein CAS, while in the cells overexpressing wild-type CSX/NKX2–5, expression of a pro-apoptotic protein RIP was reduced. Furthermore, overexpression of wild-type CSX/NKX2–5 decreased the number of H2O2-induced TUNEL-positive cultured cardiomyocytes of neonatal rats, whereas overexpression of the mutants enhanced it. These results suggest that Csx/Nkx2–5 not only regulates expression of cardiac-specific genes but protects cardiomyocytes from stresses and that cell death may be another cause for the cardiac defects induced by human CSX/NKX2–5 mutations. [Copyright &y& Elsevier]

Introduction: Low density lipoprotein receptor-related protein 6 (LRP6), a wnt co-receptor, induces wnt canonical signaling pathway involved in multiple functions. We recently reported LRP6 decreased in human dilated cardiomyopathy hearts and cardiac specific LRP6 knockout promoted cardiac dysfunction by activation of dynamin-related protein 1(Drp1) in mice. Hypothesis: We here demonstrate that cardiac specific LRP6 overexpression protects heart from ischemic-reperfusion (I/R) injury. Methods: Tamoxifen inducible cardiac specific LRP6 overexpression mice were generated, and I/R model was established by occlusion of the left anterior descending (LAD) coronary artery for 30 min and subsequent release of the occlusion for different time points. Cardiac function was analyzed by transthoracic echocardiography. Apoptosis was examined by TUNEL staining. Results: Compared to sham mice, cardiac p-LRP6 level began to increase at 15min, peaked at 30min and recovered at 1h following reperfusion in C57BL/6 mice. Tamoxifen inducible cardiac specific LRP6 overexpression significantly ameliorated myocardial I/R injury as characterized by the improved cardiac function and reduced infarct area at 24h after reperfusion. LRP6 overexpression inhibited cardiomyocytes apoptosis, evidenced by the decrease in TUNEL-positive myocytes and cleaved caspase-3 level, in I/R hearts in vivo and in H2O2-treated cardiomyocytes in vitro. Further analysis revealed that LRP6 overexpression promoted HSF1 nuclear translocation, enhanced p-GSK3β(S9) and p-AMPK level, while it didn't affect the activation of β-catenin, Drp1 or AKT in hearts after I/R or in H2O2-treated cardiomyocytes. GSK3β-S9A-AAV9 injection greatly weakened the cardiac protection induced by cardiac LRP6 overexpression against I/R injury. Si-HSF1 significantly attenuated the increase in p-GSK3β(S9) and p-AMPK level, and the inhibition of apoptosis induced by LRP6 overexpression in H2O2-treated cardiomyocytes. Conclusions: Our data suggest that cardiac LRP6 overexpression significantly inhibits cardiomyocyte apoptosis and ameliorates myocardial I/R injury by HSF1/GSK3β signaling, and AMPK activation may be involved the process. [ABSTRACT FROM AUTHOR]