Search

Cardiac microvascular injury can be a fundamental pathological process that causes high incidence cardiovascular diseases such heart failure, diabetic cardiomyopathy, and hypertension. It is also an independent risk factor for cardiovascular disease. Oxidative stress is a significant pathological process in which the body interferes with the balance of the endogenous antioxidant defense system by producing reactive oxygen species, leading to property changes and dysfunction. It has been demonstrated that oxidative stress is one of the major causes of cardiac microvascular disease. Therefore, additional investigation into the relationship between oxidative stress and cardiac microvascular injury will direct clinical management in the future. In order to give suggestions and support for future in-depth studies, we give a basic overview of the cardiac microvasculature in relation to physiopathology in this review. We also summarize the role of oxidative stress of mitochondrial and non-mitochondrial origin in cardiac microvascular injury and related drug studies.

Mitochondrial calcium uptake 1 (MICU1) is a pivotal molecule in maintaining mitochondrial homeostasis under stress conditions. However, it is unclear whether MICU1 attenuates mitochondrial stress in angiotensin II (Ang-II)-induced cardiac hypertrophy or if it has a role in the function of melatonin. Here, small-interfering RNAs against MICU1 or adenovirus-based plasmids encoding MICU1 were delivered into left ventricles of mice or incubated with neonatal murine ventricular myocytes (NMVMs) for 48 h. MICU1 expression was depressed in hypertrophic myocardia and MICU1 knockdown aggravated Ang-II-induced cardiac hypertrophy in vivo and in vitro. In contrast, MICU1 upregulation decreased cardiomyocyte susceptibility to hypertrophic stress. Ang-II administration, particularly in NMVMs with MICU1 knockdown, led to significantly increased reactive oxygen species (ROS) overload, altered mitochondrial morphology, and suppressed mitochondrial function, all of which were reversed by MICU1 supplementation. Moreover, peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α)/MICU1 expression in hypertrophic myocardia increased with melatonin. Melatonin ameliorated excessive ROS generation, promoted mitochondrial function, and attenuated cardiac hypertrophy in control but not MICU1 knockdown NMVMs or mice. Collectively, our results demonstrate that MICU1 attenuates Ang-II-induced cardiac hypertrophy by inhibiting mitochondria-derived oxidative stress. MICU1 activation may be the mechanism underlying melatonin-induced protection against myocardial hypertrophy.

Supplemental Digital Content is Available in the Text., Ischemia and anoxia-induced mitochondrial impairment may be a key factor leading to heart injury during myocardial infarction (MI). Calpain 1 and 2 are involved in the MI-induced mitochondria injury. G protein-coupled receptor 35 (GPR35) could be triggered by hypoxia. Whether or not GPR35 regulates calpain 1/2 in the pathogenesis of MI is still unclear. In this study, we determined that MI increases GPR35 expression in myocardial tissue. Suppression of GPR35 protects heart from MI injury in mice through reduction of reactive oxygen species activity and mitochondria-dependent apoptosis. Further studies show that GPR35 regulates calpain 1/2. Suppression of GPR35 reduces the expression and activity of calpain 1/2, and alleviates calpain 1/2-associated mitochondrial injury to preserve cardiac function. Based on these data, we conclude that a functional inhibition of GPR35 downregulates calpain 1/2 and contributes to maintenance of cardiac function under pathologic conditions with mitochondrial disorder. In conclusion, our study showed that the identified regulation by GPR35 of calpain 1/2 has important implications for the pathogenesis of MI. Targeting the action of GPR35 and calpain 1/2 in mitochondria presents a potential therapeutic intervention for MI.

As a serious cardiovascular complication, diabetic cardiomyopathy (DCM) refers to diabetes-related changes in myocardial structure and function, which is obviously different from those cardiomyopathy secondary to hypertension, coronary heart disease, and valvular disease. The clinical features of DCM are left ventricular hypertrophy, myocardial fibrosis, and impaired diastolic function. DCM will lead to cardiac dysfunction, eventually progress to cardiac arrhythmia, heart failure, and sudden cardiac death. At present, the pathogenesis of DCM is complex and not fully elucidated, and oxidative stress (OS), inflammatory response, glucolipid metabolism disorder, etc., are considered as the potential pathophysiological mechanisms. As a consequence, there is no specific and effective treatment for DCM. OS refers to the imbalance between reactive oxygen species (ROS) accumulation and scavenging, oxidation, and antioxidants in vivo, which is widely studied in DCM. Numerous studies have pointed out that regulating the OS signaling pathways and reducing the generation and accumulation of ROS are potential directions for the treatment of DCM. This review summarizes the major OS signaling pathways that are related to the pathogenesis of DCM, providing ideas about further research and therapy.

Microvascular protection is the main mechanism of metformin against diabetic complications. Cardiac microvascular endothelial cells (CMECs) are the basic component of cardiac microvessels, and they suffer from oxidative stress and mitochondrial dysfunction under type 2 diabetes mellitus (T2DM). Translocase of the outer mitochondrial membrane 70 (Tom70) improves mitochondrial dysfunction, but its role in the hearts of T2DM patients remains unclear. The purpose of this study was to demonstrate the protective effect of metformin on diabetic cardiac microvascular injury and to identify the role of Tom70 in this effect. T2DM mice were established by multiple intraperitoneal injections of low-dose streptozotocin and 12-week high-fat feeding. CMECs were isolated and cultured with normal glucose (NG), high glucose (HG), and HG plus high fat (HG-HF) media. The results indicated that long-term metformin treatment partly reversed cardiovascular complication and mitigated cardiac microvascular injury in T2DM. In addition, exposure to HG-HF led to CMEC damage, aggravated oxidative stress, aggravated mitochondrial dysfunction, and reduced mitochondrial Tom70 expression, whereas upregulation of Tom70 significantly ameliorated these injuries. Furthermore, metformin treatment promoted Tom70 expression and effectively reversed CMEC injury induced by HG-HF. However, all of these effects were interrupted after Tom70 was knocked down. In conclusion, T2DM damages microvascular integrity by activating a cycle of decreased Tom70 expression, mitochondrial dysfunction, and reactive oxygen species (ROS) overload in CMECs. However, metformin suppresses oxidative stress, relieves mitochondrial dysfunction, and promotes the expression of Tom70, ultimately ameliorating diabetic microvascular injury and heart complications.

Vascular restenosis badly harms the curative effect of revascularization, despite the fact that novel treatments especially percutaneous interventions of coronary, carotid and other peripheral arteries have made great progress over the past 20 years [1,2]. Therefore, revealing the underlying mechanisms and searching for novel therapeutic targets of restenosis are to be urgently solved. The initiating step of vascular restenosis is de-endothelization and compression of atherosclerotic plaque into vascular wall via mechanical injury [3]. Whereafter, activated platelet and inflammatory cells gather at damaged area and secrete several cytokines, such as platelet-derived growth factor (PDGF), interleukin-6 and interleukin-1β, and so forth [3]. These processes initiate subsequent proliferation and migration of vascular smooth muscle cells (VSMCs) and lead to neointima hyperplasia, vascular remodeling and restenosis [3]. As the major components of vascular wall, VSMCs play a crucial role in maintaining normal function of blood vessels (e.g. self-repairment) but also in neointima formation owing to the high proliferative activity [4]. Accordingly, preventing excessive VSMC proliferation is emerging as a potent method for restenosis treatment. Numerous studies have shown that, in mammalian bodies, VSMCs maintain a balance between proliferation and apoptosis. Under certain pathological conditions, VSMCs switch to a synthetic growth phenotype, which is characterized by excessive proliferation and migration [5,6]. The contractile-to-synthetic growth transition is a multifactorial process that involves many signaling pathways including cytokines, protein kinases, transcription factors and regulatory RNA molecules, and so forth. Though treatments based on aforementioned pathways, such as phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) pathways, a classical pathway regulating VSMC proliferation [7,8], have been introduced, the morbidity of restenosis still reached 10% [2]. Therefore, unraveling the novel underlying mechanism regulating VSMC proliferation is of great significance for preventing vascular restenosis. The wild-type p53-induced phosphatase 1 (Wip1), a member of the PP2C family of Ser/Thr protein phosphatases, is also addressed as protein phosphatase magnesium-dependent 1 delta (PPM1D) [9]. Overexpressed in various tumors, Wip1 is originally emerging as an oncogene regulating tumorigenesis via its regulation of apoptosis [10,11]. At the molecular level, regulation of ATM in the mammalian target of rapamycin (mTOR) and P53 is discovered to play a key role in Wip1-mediated tumorigenesis [12]. Many studies have found that Wip1 also participates in other biological processes, such as neurogenesis [13], organismal aging [14] and haematopoietic stem cell homeostasis [15]. Wip1 is recently discovered to exert a pro-atherosclerotic role in the pathological process of atherosclerosis, during which autophagy, cholesterol efflux and macrophage migration are involved [16,17]. In the above study, adenosine 5′-monophosphate-activated protein kinase (AMPK) is also confirmed to be involved in ATM-dependent regulation of mTOR [16]. Vascular restenosis has similar pathological processes to atherosclerosis, such as VSMC proliferation and migration [18], reminding us that Wip1 may also be a potent functional regulator in vascular restenosis. However, whether Wip1 is associated with VSMC proliferation, neointima hyperplasia and restenosis after vascular injury is largely unknown. In the current study, we describe a regulatory role for Wip1 in vascular restenosis, in which AMPK/mTORC1 pathway is involved. By using a Wip1 antagonist GSK2830371 (GSK), we found that Wip1 inhibition suppresses VSMC proliferation and neointima hyperplasia, accompanied by enhanced AMPK phosphorylation and decreased mTORC1 activity. Further study shows GSK fails to prevent VSMC proliferation and neointima hyperplasia in mice with tuberous sclerosis 1 (TSC1) knockdown, and thus leading to enhanced restenosis. Our research shows that Wip1-dependent modulation of VSMC proliferation and neointima hyperplasia by means of AMPK/mTORC1 may be identified as a potential therapeutic intervention for vascular restenosis.

Background: Hyper-free fatty academia (HFFA) impairs cardiac capillaries, as well as type 2 diabetes mellitus (T2DM). Perilipin 5 (Plin5) maintains metabolic balance of free fatty acids (FFAs) in high oxidative tissues via the states of non-phosphorylation and phosphorylation. However, when facing to T2DM-HFFA, Plin5's role in cardiac microvascular endothelial cells (CMECs) is not defined. Methods: In mice of WT or Plin5-/-, T2DM models were rendered by high-fat diet combined with intraperitoneal injection of streptozocin. CMECs isolated from left ventricles were incubated with high glucose (HG) and high FFAs (HFFAs). Plin5 phosphorylation was stimulated by isoproterenol. Plin5 expression was knocked down by siRNA. We determined cardiac function by small animal ultrasound, apoptotic rate by flow cytometry, microvessel quantity by immunohistochemistry, microvascular integrity by scanning electron microscopy, intracellular FFAs by spectrophotometry, lipid droplets (LDs) by nile red staining, mRNAs by quantitative real time polymerase chain reaction, proteins by western blots, nitric oxide (NO) and reactive oxygen species (ROS) by fluorescent dye staining and enzyme-linked immunosorbent assay kits. Results: In CMECs, HFFAs aggravated cell injury induced by HG and activated Plin5 expression. In mice with T2DM-HFFA, Plin5 deficiency reduced number of cardiac capillaries, worsened structural incompleteness and enhanced diastolic dysfunction. Moreover, in CMECs treated with HG-HFFAs, both ablation and phosphorylation of Plin5 reduced LDs content, increased intracellular FFAs, stimulated mitochondrial β-oxidation and added ROS generation, reduced the expression and activity of endothelial nitric oxide synthase (eNOS), eventually leading to increased apoptotic rate and decreased NO content, all of which were reversed by acetylcysteine. Conclusion: Plin5 preserves lipid balance and cell survival in diabetic CMECs by regualting FFAs metabolism bidirectionally via the states of non-phosphorylation and phosphorylation. Funding Statement: This work was supported by grants from Science Fund for Distinguished Young Scholars of Sichuan Province (No.2017JQ0012), National Science Funds of China (No.81500208), China Postdoctoral Science Foundation (No.2017M613429). Declaration of Interests: The authors declare: "No competing financial interests exist." Ethics Approval Statement: All experiments were conducted in adherence with National Institutes of Health Guidelines on the Use of Laboratory Animals, and were approved by Institutional Animal Care and Use Committee of Chengdu Military General Hospital.

Cytoplasmic lipid droplets (LDs) can store neutral lipids as an energy source when needed and also regulate the key metabolic processes of intracellular lipid accumulation, which is associated with several metabolic diseases. The perilipins (Plins) are a family of proteins that associate with the surface of LDs. As a member of Plins superfamily, perilipin 5 (Plin5) coats LDs in cardiomyocytes, which is significantly related to reactive oxygen species (ROS) production originated from mitochondria in the heart, consequently determining the progression of diabetic cardiomyopathy. Plin5 may play a bidirectional function in lipid metabolism which is in a state of dynamic balance. In the basic state, Plin5 inhibited the binding of comparative gene identification-58 (CGI-58) to adipose triglyceride lipase (ATGL) by binding CGI-58, thus inhibiting lipolysis. However, when the body is under stress (such as cold, fasting, exercise, and other stimuli), protein kinase A (PKA) phosphorylates and activates Plin5, which then causes Plin5 to release the binding site of CGI-58 and ATGL, prompting CGI-58 to bind to ATGL and activate ATGL activity, thus accelerating the lipolysis process, revealing the indispensable role of Plin5 in lipid turnover. Here, the purpose of this review is to summarize the present understanding of the bidirectional regulation role of Plin5 in oxidative tissues and to reveal its potential role in diabetic cardiomyopathy protection.

Cardiac microvascular injury often occurs in patients with type 2 diabetes mellitus (T2DM) who develop hyperglycemia and hyperlipidemia. However, besides reported contradictory roles in cardiac diseases, the function of TRPV1 (transient receptor potential vanilloid 1) in cardiac microvessels is not well defined. This study was performed to determine the detailed role of TRPV1 in cardiac microvascular endothelial cells (CMECs) in T2DM. T2DM mice were established by multiple injections of low-dose streptozotocin and high-fat feeding. CMECs were cultured separately in mediums of normal glucose, high glucose (HG), high fatty acid (HF), and HG plus HF (HG-HF). HG-HF inhibited TRPV1 expression in CMECs, reducing cellular Ca 2+ content ([Ca 2+ ] i ). T2DM impaired cardiac function, disturbed glucose uptake, and damaged microvascular barrier, which were further aggravated by TRPV1 −/− . Exposure to HG-HF, particularly in TRPV1 −/− CMECs, led to a higher level of apoptosis and a lower level of nitric oxide production in viable CMECs. HG-HF markedly enhanced generation of reactive oxygen species and nitrotyrosine, especially in the absence of TRPV1. H 2 O 2 administration reduced TRPV1 expression in CMECs. HG-HF significantly depressed expression of PGC-1α (peroxisome proliferator–activated receptor-γ coactivator-1α) and OPA1 (optic atrophy 1) by reducing [Ca 2+ ] i , whereas OPA1 supplementation partly reversed those detrimental effects induced by TRPV1 −/− . Furthermore, capsaicin treatment not only attenuated CMECs injury induced by HG-HF but also mitigated cardiac microvascular injury induced by T2DM. Collectively, T2DM leads to cardiac microvascular injury by exacerbating the vicious circle of TRPV1 blockage and reactive oxygen species overload. Long-term capsaicin can protect cardiac microvessels against T2DM via suppressing oxidative/nitrative stress mediated by TRPV1/Ca 2+ /PGC-1α/OPA1 pathway in CMECs.

The pathogenesis of myocardial ischaemia/reperfusion injury is multifactorial. Understanding the mechanisms of myocardial ischaemia/reperfusion will benefit patients with ischaemic heart disease. Growth differentiation factor 11 (GDF11), a member of the secreted transforming growth factor-β superfamily, has been found to reverse age-related hypertrophy, revealing the important role of GDF11 in cardiovascular disease. However, the functions of GDF11 in myocardial ischaemia/reperfusion have not been elucidated yet. A number of signalling molecules are known to occur downstream of GDF11, including mothers against decapentaplegic homolog 3 (SMAD3) and forkhead box O3a (FOXO3a). A hypothesis is presented that GDF11 has protective effects in acute myocardial ischaemia/reperfusion injury through suppression of oxidative stress, prevention of calcium ion overload and promotion of the elimination of abnormal mitochondria via both canonical (SMAD3) and non-canonical (FOXO3a) pathways. Since circulating GDF11 may mainly derive from the spleen, the lack of a spleen may make the myocardium susceptible to damaging insults. Administration of GDF11 may be an efficacious therapy to protect against cardiovascular diseases in splenectomized patients.

Fully mechanised caving mining is widely used because it can quickly convert coal resources into productivity advantages. The water resources of Bayangol coal mine is scarce and the vegetation cove...

Background: Temperature control plays a pivotal role in patients with heat stroke (HS), but little work has been done sufficiently on the use of temperature control to reflect disease progression. Here, we defined and analyzed the concrete role of effective controlling time for core temperature to physiological level (CTTP), in order to explore a potential index to guide the diagnosis and treatment of HS. Method: According to Chinese physical characteristics and the consensus of chinese experts, we defined CTTP as time interval of HS onset to stabilization of core temperature (rectal temperature) below 37.7℃. From 2010.01 to 2018.06 in our hospital, we collected a total of 28 HS cases with clinical diagnosis and treatment records for analyzing the correlation between CTTP and organ injuries, prognosis, APACHE II score and other indices. Results: There was a significant growth of exertional HS cases year by year, whereas the hospital mortality remained steady over the years, with an overall mortality rate being 17.85%. After analyzing the basic characteristics of CTTP, we found that it didn't obey normal distribution (P 0.05). Moreover, CTTP length determined the number of damaged organs (r=0.494, P=0.008). The top five of damaged organs in HS patients were central nervous system disorder (100%), liver injury (78.57%), renal injury (67.86%), myocardial injury (57.14%) and blood coagulation disorder (53.57%). Furthermore, some patients with organ injuries, such as renal function impairment, myocardial damage, pulmonary infection, had both higher mean and median of CTTP than the couterpart (P 0.05). Most importantly, CTTP was closely correlated with APACHE II score (r=0.888, P

Ischemic heart diseases (IHD) have become the leading cause of death around the world, killing more than 7 million people annually. In IHD, the blockage of coronary vessels will cause irreversible cell injury and even death. As the “powerhouse” and “apoptosis center” in cardiomyocytes, mitochondria play critical roles in IHD. Ischemia insult can reduce myocardial ATP content, resulting in energy stress and overproduction of reactive oxygen species (ROS). Thus, mitochondrial abnormality has been identified as a hallmark of multiple cardiovascular disorders. To date, many studies have suggested that these mitochondrial proteins, such as electron transport chain (ETC) complexes, uncoupling proteins (UCPs), mitochondrial dynamic proteins, translocases of outer membrane (Tom) complex, and mitochondrial permeability transition pore (MPTP), can directly or indirectly influence mitochondria-originated ROS production, consequently determining the degree of mitochondrial dysfunction and myocardial impairment. Here, the focus of this review is to summarize the present understanding of the relationship between some mitochondrial functional proteins and ROS production in IHD.

TNF-α inhibitor reportedly protects against myocardial ischemia/reperfusion (MI/R) injury. It can also increase Notch1 expression in inflammatory bowel disease, revealing the regulation of Notch1 signaling by TNF-α inhibitor. However, the interaction between TNF-α inhibitor and Notch1 signaling in MI/R remains unclear. This study aimed to determine the involvement of TNF-α inhibitor with Notch1 in MI/R and delineate the related mechanism. Notch1-specific small interfering RNA (20 μg) or Jagged1 (a Notch ligand, 12 μg) was delivered through intramyocardial injection. Forty-eight hours after injection, mice received 30 min of myocardial ischemia followed by 3 h (for cell apoptosis and oxidative/nitrative stress) or 24h (for infarct size and cardiac function) of reperfusion. Ten minutes before reperfusion, mice randomly received an intraperitoneal injection of vehicle, etanercept, diphenyleneiodonium, 1400W, or EUK134. Finally, downregulation of Notch1 significantly reversed the alleviation of MI/R injury induced by etanercept, as evidenced by enlarged myocardial infarct size, suppressed cardiac function, and increased myocardial apoptosis. Moreover, Notch1 blockade increased the expression of inducible NO synthase (iNOS) and gp(91)(phox), enhanced NO and superoxide production, and accelerated their cytotoxic reaction product, peroxynitrite. Furthermore, NADPH inhibition with diphenyleneiodonium or iNOS suppression with 1400W mitigated the aggravation of MI/R injury induced by Notch1 downregulation in mice treated with etanercept. Additionally, either Notch1 activation with Jagged1 or peroxynitrite decomposition with EUK134 reduced nitrotyrosine content and attenuated MI/R injury. These data indicate that MI/R injury can be attenuated by TNF-α inhibitor, partly via Notch1 signaling-mediated suppression of oxidative/nitrative stress.

Background Bone mesenchymal stem cell (BMSC) therapy has modest success in ischemic heart disease but has been limited by poor survival in diseased microenvironments. Cellular repressor of E1A-stimulated genes (CREG) can prevent BMSCs from apoptosis in vitro ; however, the effects of CREG-modified BMSCs on ischemic heart disease and the related mechanism remain undefined. Therefore, we designed to study the cardioprotective effects of CREG overexpression in BMSCs ( CREG BMSCs) after transplantation into infarcted heart of rats. Methods In vivo studies, 50μl PBS or 1.5×10 6 Norm BMSCs, GFP BMSCs or CREG BMSCs were implanted intramyocardially in myocardial infarction rat models. 3 or 14days later, cardiac function, fibrosis, apoptosis and angiogenesis were analyzed by echocardiography, masson, western blot and immunofluorescence staining, respectively. ELISA, western blot and matrigel assay were used in vitro to detect vascular endothelial growth factor (VEGF) secretion, signaling molecule expression, and angiogenic tube formation. Results In vivo , prolonged cardiac function (14d LVEF: 50.87±0.94%; LVFS: 23.41±1.12%), decreased fibrosis (14d Fibrotic area: 27.37±1.03%) and apoptosis and increased angiogenesis were observed in CREG BMSCs, compared with other groups. In vivo and in vitro , VEGF secretion from CREG BMSCs was markedly enhanced. In vitro , angiogenic tube formation in CREG BMSC supernatants significantly increased. Moreover, CREG activated hypoxia-inducible factor-1α (HIF-1α), but not HIF-1β. Knockdown of HIF-1α with siRNA decreased VEGF secretion and angiogenic tube formation. Notably, CREG did not influence HIF-1α mRNA synthesis but inhibited the expression of Von Hippel–Lindau (VHL), a key protein that regulates HIF-1α degradation. Conclusions The CREG BMSC transplantation, directly or indirectly, may promote VEGF's anti-apoptosis and angiogenesis via the inhibition of VHL-mediated HIF-1α degradation, consequently protecting against myocardial infarction.

Mitochondrial calcium uptake 1 (MICU1) serves as a pivotal molecule in maintaining mitochondrial homeostasis, but its concrete role in cardiac hypertrophy remains elusive yet. The β3-adrenergic receptor (β3-AR) has received considerable attention of the world in cardiac hypertrophy, whether it possesses mutual restriction relation with MICU1 deserves further investigation. Specific small interfering RNAs against MICU1 or adenovirus-based plasmid with MICU1 were delivered into left ventricles or incubated with neonatal murine ventricular myocytes (NMVMs) for 48 h. Then, mice were rendered to cardiac hypertrophy by chronic infusion of angiotensin II (Ang-II) with a mini-osmotic pump for 28 days, meanwhile NMVMs were cultured with Ang-II for 48 h. Finally, MICU1 expression was downregulated in hypertrophic myocardium. MICU1 ablation aggravated cardiac hypertrophy both in vivo and in vitro, evidenced by impaired cardiac function, enlarged cardiomyocytes, increased hypertrophic maker genes and enhanced reactive oxygen species (ROS) generation. Moreover, excessive ROS accumulation following MICU1 deficiency increased β3-AR expression, which was reversed by N-acetyl-L-cysteine (NAC). In addition, β3-AR agonists BRL37344 depressed expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and MICU1, leading to aggravated cardiac hypertrophy. However, MICU1 supplementation eliminated those detrimental effects of BRL37344, and decreased the susceptibility of cardiomyocytes to hypertrophic stress. Furthermore, in hypertrophicmyocardium, melatonin alone, but not when combined with luzindole, inhibited β3-AR expression, accompanied with increased expression of PGC-1α/MICU1 and decreased generation of ROS, finally contributing to alleviated cardiac hypertrophy. Conclusively, the mutual antagonism of β3-AR and MICU1 gives rise to pathologic development of cardiac hypertrophy, and melatonin protects against hypertrophic stress by negative regulating the abovementioned pathway. Funding Statement: This work was supported by grants from National Science Funds of China (No.81500208; 81670419), Science Fund for Distinguished Young Scholars of Sichuan Province (No.2017JQ0012), China Postdoctoral Science Foundation (No.2017M613429). Declaration of Interests: The authors state: No competing financial interests exist. Ethics Approval Statement: All experiments performed in adherence to the National Institutes of Health Guidelines on the Use of Laboratory Animals (Bethesda, MD, USA) and conformed to the Institutional Animal Care and Use Committee of Chengdu Military General Hospital.

Silent information regulator 1 (SIRT1), a class III histone deacetylase, retards aging and plays roles in cellular oxidative stress injury (OSI). However, the biological context in which SIRT1 promotes oxidative injury is not fully understood. Here, we show that SIRT1 essentially mediates hydrogen peroxide (H2O2)-induced cytotoxicity in human umbilical vein endothelial cell (HUVEC). In HUVECs, SIRT1 protein expression was significantly increased in a dose-dependent manner after H2O2 treatment, whereas the acetylation levels of the NF-κB p65 subunit and p53 were decreased. EX527 (a specific SIRT1 inhibitor) conferred protection to the HUVECs against H2O2, as indicated by an improved cell viability, adhesion, an enhanced migratory ability, a decreased apoptotic index, decreased reactive oxygen species (ROS) production and reductions in several biochemical parameters. Immunofluorescence and Western blot analyses demonstrated that H2O2 treatment up-regulated SIRT1, phosphorylated-JNK (p-JNK), p-p38MAPK, and p-ERK expression. EX527 pretreatment reversed these effects on SIRT1, p-JNK, and p-p38MAPK but further increased the p-ERK levels. Similar results were confirmed in SIRT1 siRNA experiments. In summary, SIRT1 signaling pathway inhibition imparts protection against acute endothelial OSI, and modulation of MAPKs (JNK, p38MAPK, and ERK) may be involved in the protective effect of SIRT1 inhibition.

Melatonin confers cardioprotective effect against myocardial ischemia/reperfusion (MI/R) injury by reducing oxidative stress. Activation of silent information regulator 1 (SIRT1) signaling also reduces MI/R injury. We hypothesize that melatonin may protect against MI/R injury by activating SIRT1 signaling. This study investigated the protective effect of melatonin treatment on MI/R heart and elucidated its potential mechanisms. Rats were exposed to melatonin treatment in the presence or the absence of the melatonin receptor antagonist luzindole or SIRT1 inhibitor EX527 and then subjected to MI/R operation. Melatonin conferred a cardioprotective effect by improving postischemic cardiac function, decreasing infarct size, reducing apoptotic index, diminishing serum creatine kinase and lactate dehydrogenase release, upregulating SIRT1, Bcl-2 expression and downregulating Bax, caspase-3 and cleaved caspase-3 expression. Melatonin treatment also resulted in reduced myocardium superoxide generation, gp91(phox) expression, malondialdehyde level, and increased myocardium superoxide dismutase (SOD) level, which indicate that the MI/R-induced oxidative stress was significantly attenuated. However, these protective effects were blocked by EX527 or luzindole, indicating that SIRT1 signaling and melatonin receptor may be specifically involved in these effects. In summary, our results demonstrate that melatonin treatment attenuates MI/R injury by reducing oxidative stress damage via activation of SIRT1 signaling in a receptor-dependent manner.

The branched-chain amino acids (BCAA) accumulated in type 2 diabetes are independent contributors to insulin resistance. The activity of branched-chain α-keto acid dehydrogenase (BCKD) complex, rate-limiting enzyme in BCAA catabolism, is reduced in diabetic states, which contributes to elevated BCAA concentrations. However, the mechanisms underlying decreased BCKD activity remain poorly understood. Here, we demonstrate that mitochondrial phosphatase 2C (PP2Cm), a newly identified BCKD phosphatase that increases BCKD activity, was significantly downregulated in ob/ob and type 2 diabetic mice. Interestingly, in adiponectin (APN) knockout (APN−/−) mice fed with a high-fat diet (HD), PP2Cm expression and BCKD activity were significantly decreased, whereas BCKD kinase (BDK), which inhibits BCKD activity, was markedly increased. Concurrently, plasma BCAA and branched-chain α-keto acids (BCKA) were significantly elevated. APN treatment markedly reverted PP2Cm, BDK, BCKD activity, and BCAA and BCKA levels in HD-fed APN−/− and diabetic animals. Additionally, increased BCKD activity caused by APN administration was partially but significantly inhibited in PP2Cm knockout mice. Finally, APN-mediated upregulation of PP2Cm expression and BCKD activity were abolished when AMPK was inhibited. Collectively, we have provided the first direct evidence that APN is a novel regulator of PP2Cm and systematic BCAA levels, suggesting that targeting APN may be a pharmacological approach to ameliorating BCAA catabolism in the diabetic state.

Restenosis limits the efficacy of vascular percutaneous intervention, in which vascular smooth muscle cell (VSMC) proliferation and activation of inflammation are two primary causal factors. Calpains influence VSMC proliferation and collagen synthesis. However, the roles of calpastatin and calpains in vascular restenosis remain unclear. Here, restenosis was induced by ligating the left carotid artery and VSMCs were pretreated with platelet-derived growth factor (PDGF)-BB. Adenovirus vector carrying MMP2 sequence and specific small interfering RNA against calpain-1/2 were introduced. Finally, restenosis enhanced the expression of calpain-1/2, but reduced calpastatin content. In calpastatin transgenic mice, lumen narrowing was attenuated gradually and peaked on days 14–21. Cell proliferation and migration as well as collagen synthesis were inhibited in transgenic mice and expression of calpain-1/2 and MMP2/transforming growth factor-β1 (TGF-β1). Consistently, in VSMCs pretreated with PDGF-BB, calpastatin induction and calpains inhibition suppressed the proliferation and migration of VSMCs and collagen synthesis and reduced expression of calpain-1/2 and MMP2/TGF-β1. Moreover, simvastatin improved restenosis indicators by suppressing the HIF-1α/calpains/MMP2/TGF-β1 pathway. However, MMP2 supplementation eliminated the vascular protection of calpastatin induction and simvastatin. Collectively, calpains inhibition plays crucial roles in vascular restenosis by preventing neointimal hyperplasia at the early stage via suppression of the MMP2/TGF-β1 pathway.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a crucial health problem. With sudden death often being the first presentation, early diagnosis for ARVC is essential. Up to date, electrocardiogram (ECG) is a widely used diagnostic method without invasive harms. To diagnose and treat ARVC as well as possible, we should clearly elucidate its pathophysiological alterations. A 66-year-old farmer presented to the Emergency Department with continuous palpitation, chest tightness, profuse sweating, and nausea with no obvious predisposing causes. An ECG indicated ventricular tachycardia (VT). The patient experienced a sudden drop in blood pressure and acute confusion. After an immediate electrical conversion, his consciousness was gradually restored, and symptoms relieved. The patient was then transferred to the Department of Cardiology to receive ECG, echocardiography, coronary angiogram, biochemical assays, endocardiac tracing, and radiofrequency ablation. In the end, he was diagnosed with ARVC, evidenced by bilateral ventricle dilation and epsilon waves in leads V1–V3. Appropriate therapies were provided for this patient including pharmacological intervention and radiofrequency ablation. Although the diagnosis of ARVC is not difficult, this patient's ECG manifested several interesting features and should be further investigated: T wave inversions were found extensively in the anterior and inferior leads, revealing the involvement of bilateral ventricles; VTs with different morphologies and cycle lengths were found, and some VTs manifested the feature of irregularly irregular rhythm, reminding us to carefully differentiate some special VTs from atrial fibrillation (AF); and epsilon waves gradually appeared in leads V1–V3 and avR since the onset of ARVC. Most importantly, the epsilon waves behind QRS complex appeared in both sinus rhythm and ventricular premature beats/VT originating from cardiac apex, whereas the epsilon waves prior to QRS complex occurred in VT originating from right ventricular outflow tract (RVOT). The features of T wave inversion and epsilon wave in ECGs and the appearance of VTs with different morphologies can reflect the progression of ARVC. The position relationship between epsilon wave and QRS complex in VT depends on ventricular activation sequence, that is, the localization of epsilon wave depends on where VT is originating from.

As one main active compound of curcuminoids, Bisdemethoxycurcumin (BDMC) possesses several biological activities, such as anti-inflammation and anti-cancer activities. However, the detailed mechanism of BDMC’s anti-metastasis activity in ovarian cancer has not been clearly elucidated yet. In the present study, cell proliferation, wound healing motility, cell adhesion and invasion with or without BDMC were determined. In addition, western blot was used to examine proteins expressions. The lucigenin-enhanced luminescence was introduced to assess cellular oxidative stress. The luciferase reporter gene assay was introduced to evaluate the transcriptional activity of NF-κB. Finally, BDMC significantly inhibited the adhesion, migration, invasion and metastasis of SKOV-3 cells. Moreover, BDMC inhibited expressions of several degradation-associated proteins, such as matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), CD147, urokinase plasminogen activator (uPA), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), whereas increased expression of tissue inhibitor of metalloproteinase-1 (TIMP-1), in a dose-dependent manner. In addition, BDMC reduced generation of cellular superoxide in a dose-dependent manner. Furthermore, BDMC inhibited the phosphorylation levels of NF-κB p65 and IκB-α and consequently reduced NF-κB-driven luciferase expression. Collectively, BDMC serves as a therapeutic medicine to suppress ovarian cancer, perhaps via inhibiting cellular oxidative stress and subsequently inactivating NF-κB pathway.

Mitochondrial dysfunction is linked with myocardial infarction (MI), a disorder in which Notch1 has attracted increasing attention. However, the involvement of Notch1 in mitochondrial impairment after an MI is poorly understood, as is the role of mitochondrial fusion-associated protein 2 (Mfn2). Moreover, whether melatonin potentiates the Notch1/Mfn2 pathway in post-MI cardiac damage remains unclear. In our study, small interfering RNAs against Notch1 or Mfn2 and Jagged1 peptide were delivered via intramyocardial injection. At 3 days after these treatments, MI was induced by ligation of the anterior descending branch. We found that this ablation of Notch1 or Mfn2 aggravated post-MI injury, including worsened mitochondrial damage and increased generation of reactive oxygen species (ROS). In contrast, Jagged1 improved mitochondrial structure and function, decreased ROS production and attenuated post-MI injury. Interestingly, though Mfn2 expression was mildly regulated by Notch1 signaling in myocardium, Mfn2 deficiency nearly eliminated the cardioprotection by Jagged1, as evidenced by suppressed cardiac function, aggravated myocardial fibrosis, increased cell apoptosis, worsened mitochondrial impairment and enhanced oxidative stress. These observations revealed that Mfn2 plays an indispensable role in protection against MI-induced injury by Notch1. The mechanism might involve disrupting a damaging cycle of mitochondrial damage and ROS generation. Furthermore, melatonin activated Notch1 signaling and increased Mfn2 expression were reversed by luzindole, a nonselective antagonist of the melatonin receptor. Notably, melatonin attenuated post-MI injury in normal mice, but not in mice deficient in Notch1 or Mfn2. These results demonstrate that melatonin attenuates post-MI injury via the Notch1/Mfn2 pathway in a receptor-dependent manner.

Objective Transient receptor potential vanilloid 1 (TRPV1) is an important regulator of endothelial function, but the effects of TRPV1 on endothelial recovery and neointimal formation after vascular injury remain elusive. We tested the effects of activating TRPV1 using capsaicin on re-endothelialization and neointimal formation after wire-induced injury of the carotid artery in mice. Methods The human umbilical vein endothelial cells (HUVECs) were treated with the TRPV1 agonist capsaicin, its antagonist capsazepine, intracellular calcium chelator BAPTA, or mitofusin 2 (Mfn2)-specific short interfering RNA (siRNA). The migration, proliferation, mitochondrial morphology, membrane potential, and adenosine triphosphate production were measured. The carotid artery wire injury procedure was performed in male TRPV1 knockout mice and C57BL/6J wild-type (WT) mice that were then treated with or without Mfn2 siRNA. The re-endothelialization and neointimal formation were evaluated. Results Capsaicin significantly enhanced the migration and proliferation of HUVECs. Both capsazepine and BAPTA abolished capsaicin-induced migration and proliferation of HUVECs. In addition, capsaicin stimulated the formation of reticular mitochondria, augmented mitochondrial membrane potential, increased adenosine triphosphate production, and upregulated Mfn2. However, these effects were attenuated by knockdown of Mfn2 with specific siRNA. Dietary capsaicin markedly accelerated re-endothelialization and inhibited neointimal formation in WT mice but not in TRPV1 knockout mice. Moreover, Mfn2 siRNA also attenuated capsaicin-induced enhancement of endothelial recovery and suppression of neointimal hyperplasia in WT mice. Conclusions Activation of TRPV1 with capsaicin attenuates neointimal formation by accelerating re-endothelialization through upregulation of Mfn2.

Mitochondrial Ca2+ overload is a main contributor to mitochondrial damage hence cardiomyocyte death in myocardial ischemia/reperfusion (MI/R) injury. MICU1 has been recently identified as an important regulator of mitochondrial Ca2+ homeostasis. Here we try to identify the role of MICU1 in MI/R, and to investigate whether the mitochondrial importer receptor Tom70 possesses critical roles in the mitochondrial translocation of MICU1 and MI/R. Specific small interfering RNA (20 μg) against MICU1 and Tom70, and lentivirus vectors carrying the Tom70a sequences (3.3 × 107 TU) were delivered through intramyocardial injection. Seventy-two hours after injection, mice were subjected to 30 min of MI followed by 3 h (for cell apoptosis and mitochondrial damage assessment) or 24 h (for cardiac function and infarct size determination) of reperfusion. MI/R had no significant effect on total MICU1 expression, but caused significant reduction of MICU1 in mitochondria. Knockdown of MICU1 significantly aggravated MI/R injury, as evidenced by enlarged infarct size, depressed cardiac function and increased myocardial apoptosis. Moreover, MICU1 deficiency resulted in markedly aggravated mitochondrial Ca2+ overload, consequently destructed mitochondrial morphology and suppressed mitochondrial function (evidenced by decreased ATP production). Interestingly, mitochondrial Tom70 was also decreased in MI/R. Genetic loss-function study revealed that mitochondrial MICU1 expression was depressed by Tom70 ablation. Furthermore, Tom70 deficiency significantly aggravated MI/R injury and worsened mitochondrial Ca2+ overload. However, supplementation of Tom70 significantly attenuated MI/R injury, preserved mitochondrial morphology and function, and inhibited mitochondrial Ca2+ overload, all of which were abolished by MICU1 suppression. Mitochondrial Tom70/MICU1 pathway protects against MI/R injury, in which mitochondrial localization of MICU1 is governed by Tom70, and MICU1 serves as an indispensable factor in Tom70’s cardioprotection.