MCP-1 induces cardioprotection against ischaemia/reperfusion injury: role of reactive oxygen species

Repair of the Infarcted Heart: Cellular Effectors, Molecular Mechanisms and Therapeutic Opportunities

The adult mammalian heart has limited endogenous regenerative capacity and heals through the activation of inflammatory and fibrogenic cascades that ultimately result in the formation of a scar. After infarction, massive cardiomyocyte death releases a broad range of damage-associated molecular patterns that initiate both myocardial and systemic inflammatory responses. TLRs (toll-like receptors) and NLRs (NOD-like receptors) recognize damage-associated molecular patterns (DAMPs) and transduce downstream proinflammatory signals, leading to upregulation of cytokines (such as interleukin-1, TNF-α [tumor necrosis factor-α], and interleukin-6) and chemokines (such as CCL2 [CC chemokine ligand 2]) and recruitment of neutrophils, monocytes, and lymphocytes. Expansion and diversification of cardiac macrophages in the infarcted heart play a major role in the clearance of the infarct from dead cells and the subsequent stimulation of reparative pathways. Efferocytosis triggers the induction and release of anti-inflammatory mediators that restrain the inflammatory reaction and set the stage for the activation of reparative fibroblasts and vascular cells. Growth factor-mediated pathways, neurohumoral cascades, and matricellular proteins deposited in the provisional matrix stimulate fibroblast activation and proliferation and myofibroblast conversion. Deposition of a well-organized collagen-based extracellular matrix network protects the heart from catastrophic rupture and attenuates ventricular dilation. Scar maturation requires stimulation of endogenous signals that inhibit fibroblast activity and prevent excessive fibrosis. Moreover, in the mature scar, infarct neovessels acquire a mural cell coat that contributes to the stabilization of the microvascular network. Excessive, prolonged, or dysregulated inflammatory or fibrogenic cascades accentuate adverse remodeling and dysfunction. Moreover, inflammatory leukocytes and fibroblasts can contribute to arrhythmogenesis. Inflammatory and fibrogenic pathways may be promising therapeutic targets to attenuate heart failure progression and inhibit arrhythmia generation in patients surviving myocardial infarction.

NADPH Oxidase 3: Beyond the Inner Ear

Reactive oxygen species (ROS) were formerly known as mere byproducts of metabolism with damaging effects on cellular structures. The discovery and description of NADPH oxidases (Nox) as a whole enzyme family that only produce this harmful group of molecules was surprising. After intensive research, seven Nox isoforms were discovered, described and extensively studied. Among them, the NADPH oxidase 3 is the perhaps most underrated Nox isoform, since it was firstly discovered in the inner ear. This stigma of Nox3 as "being only expressed in the inner ear" was also used by me several times. Therefore, the question arose whether this sentence is still valid or even usable. To this end, this review solely focuses on Nox3 and summarizes its discovery, the structural components, the activating and regulating factors, the expression in cells, tissues and organs, as well as the beneficial and detrimental effects of Nox3-mediated ROS production on body functions. Furthermore, the involvement of Nox3-derived ROS in diseases progression and, accordingly, as a potential target for disease treatment, will be discussed.

Similarities and differences between myocarditis following COVID-19 mRNA vaccine and multiple inflammatory syndrome with cardiac involvement in children

Despite the multiple benefits of vaccination, cardiac adverse Events Following COVID-19 Immunization (c-AEFI) have been reported. These events as well as the severe cardiac involvement reported in Multisystem inflammatory syndrome in children (MIS-C) appear more frequent in young adult males. Herein, we firstly report on the inflammatory profiles of patients experiencing c-AEFI in comparison with age, pubertal age and gender matched MIS-C with cardiac involvement. Proteins related to systemic inflammation were found higher in MIS-C compared to c-AEFI, whereas a higher level in proteins related to myocardial injury was found in c-AEFI. In addition, higher levels of DHEAS, DHEA, and cortisone were found in c-AEFI which persisted at follow-up. No anti-heart muscle and anti-endothelial cell antibodies have been detected. Overall current comparative data showed a distinct inflammatory and androgens profile in c-AEFI patients which results to be well restricted on heart and to persist months after the acute event.

Xenotopic expression of alternative oxidase (AOX) to study mechanisms of mitochondrial disease

The mitochondrial respiratory chain or electron transport chain (ETC) facilitates redox reactions which ultimately lead to the reduction of oxygen to water (respiration). Energy released by this process is used to establish a proton electrochemical gradient which drives ATP formation (oxidative phosphorylation, OXPHOS). It also plays an important role in vital processes beyond ATP formation and cellular metabolism, such as heat production, redox and ion homeostasis. Dysfunction of the ETC can thus impair cellular and organismal viability and is thought to be the underlying cause of a heterogeneous group of so-called mitochondrial diseases. Plants, yeasts, and many lower organisms, but not insects and vertebrates, possess an enzymatic mechanism that confers resistance to respiratory stress conditions, i.e., the alternative oxidase (AOX). Even in cells that naturally lack AOX, it is autonomously imported into the mitochondrial compartment upon xenotopic expression, where it refolds and becomes catalytically engaged when the cytochrome segment of the ETC is blocked. AOX was therefore proposed as a tool to study disease etiologies. To this end, AOX has been xenotopically expressed in mammalian cells and disease models of the fruit fly and mouse. Surprisingly, AOX showed remarkable rescue effects in some cases, whilst in others it had no effect or even exacerbated a condition. Here we summarize what has been learnt from the use of AOX in various disease models and discuss issues which still need to be addressed in order to understand the role of the ETC in health and disease.

Monocyte chemotactic protein (MCP)-1 (CCL2) and its receptor (CCR2) are elevated in chronic heart failure facilitating lung monocyte infiltration and differentiation which may contribute to lung fibrosis

BACKGROUND

Dyspnea, the cardinal manifestation of chronic heart failure (CHF), may reflect both pulmonary oedema and pulmonary remodeling resulting in tissue stiffening. Emerging evidence suggests that predominance of distinct phenotypes of alveolar and recruited macrophages, designated M1 and M2, may regulate the course of inflammatory tissue repair and remodeling in the lung.

METHODS

In a CHF rat model, we found fibrotic reinforcement of the extracellular matrix with an increase in monocyte chemotactic protein (MCP)-1/CCL2 in bronchoalveolar lavage (BAL), corresponding to a 3-fold increase in recruited macrophages. In this clinical cross sectional study, we aimed to examine potential mediators of leukocyte activation and lung infiltration in parallel BAL and blood from CHF patients compared to non-CHF controls.

RESULTS

Mini-BAL and peripheral blood samples were obtained from hospitalized CHF, acute decompensated CHF and non-CHF patients. CHF patients and decompensated CHF patients demonstrated increases from non-CHF patients in BAL MCP-1, as well as the M2 macrophage cytokines interleukin-10 and transforming growth factor-β. BAL and plasma MCP-1 were significantly correlated; however, MCP-1 was 20-fold higher in epithelial lining fluid in BAL, indicative of an alveolar chemotactic gradient. An increase in transglutaminase 2 positive M2 macrophages in parallel with a decrease in the MCP-1 receptor, CC chemokine receptor 2 (CCR2), was apparent in BAL cells of CHF patients compared to non-CHF.

CONCLUSION

These data suggest a pathway of MCP-1 mediated M2 macrophage prevalence in the lungs of CHF patients which may contribute to pulmonary fibrotic remodeling and consequent increased severity of dyspnea.

Circulating Monocyte Chemoattractant Protein-1 in Patients with Cardiogenic Shock Complicating Acute Myocardial Infarction Treated with Mild Hypothermia: A Biomarker Substudy of SHOCK-COOL Trial

Background: There is evidence that monocyte chemoattractant protein-1 (MCP-1) levels reflect the intensity of the inflammatory response in patients with cardiogenic shock (CS) complicating acute myocardial infarction (AMI) and have a predictive value for clinical outcomes. However, little is known about the effect of mild therapeutic hypothermia (MTH) on the inflammatory response in patients with CS complicating AMI. Therefore, we conducted a biomarker study to investigate the effect of MTH on MCP-1 levels in patients with CS complicating AMI. Methods: In the randomized mild hypothermia in cardiogenic shock (SHOCK-COOL) trial, 40 patients with CS complicating AMI were enrolled and assigned to MTH (33 °C) for 24 h or normothermia at a 1:1 ratio. Blood samples were collected at predefined time points at the day of admission/day 1, day 2 and day 3. Differences in MCP-1 levels between and within the MTH and normothermia groups were assessed. Additionally, the association of MCP-1 levels with the risk of all-cause mortality at 30 days was analyzed. Missing data were accounted for by multiple imputation as sensitivity analyses. Results: There were differences in MCP-1 levels over time between patients in MTH and normothermia groups (P for interaction = 0.013). MCP-1 levels on day 3 were higher than on day 1 in the MTH group (day 1 vs day 3: 21.2 [interquartile range, 0.25–79.9] vs. 125.7 [interquartile range, 87.3–165.4] pg/mL; p = 0.006) and higher than in the normothermia group at day 3 (MTH 125.7 [interquartile range, 87.3–165.4] vs. normothermia 12.3 [interquartile range, 0–63.9] pg/mL; p = 0.011). Irrespective of therapy, patients with higher levels of MCP-1 at hospitalization tended to have a decreased risk of all-cause mortality at 30 days (HR, 2.61; 95% CI 0.997–6.83; p = 0.051). Conclusions: The cooling phase of MTH had no significant effect on MCP-1 levels in patients with CS complicating AMI compared to normothermic control, whereas MCP-1 levels significantly increased after rewarming. Trial registration: NCT01890317.

Role of CCR2-Positive Macrophages in Pathological Ventricular Remodelling

Even with recent advances in care, heart failure remains a major cause of morbidity and mortality, which urgently needs new treatments. One of the major antecedents of heart failure is pathological ventricular remodelling, the abnormal change in the size, shape, function or composition of the cardiac ventricles in response to load or injury. Accumulating immune cell subpopulations contribute to the change in cardiac cellular composition that occurs during ventricular remodelling, and these immune cells can facilitate heart failure development. Among cardiac immune cell subpopulations, macrophages that are recognized by their transcriptional or cell-surface expression of the chemokine receptor C-C chemokine receptor type 2 (CCR2), have emerged as playing an especially important role in adverse remodelling. Here, we assimilate the literature that has been generated over the past two decades describing the pathological roles that CCR2+ macrophages play in ventricular remodelling. The goal is to facilitate research and innovation efforts in heart failure therapeutics by drawing attention to the importance of studying the manner by which CCR2+ macrophages mediate their deleterious effects.

Attenuation of lipid metabolic abnormalities, proinflammatory cytokines, and matrix metalloproteinase expression by biochanin-A in isoproterenol-induced myocardial infarction in rats

In the present study, we assessed the therapeutic potential of Biochanin-A (BCA) (10 mg/kg BW/day) pretreatment for 30 days on lipid metabolic abnormalities, proinflammatory cytokines and matrix metalloproteinase expression in isoproterenol (ISO)-induced myocardial infarction (MI) in rats. We measured the potential role of BCA on tissue and circulatory lipid profiles as well as on lipid metabolic enzymes: serum inflammatory cytokines (TNF-α, IL-1α, IL-1β, IL-6 and MCP1) and serum Matrix Metalloproteinases (particularly, MMP-2 and MMP-9) together with mRNA expressions of TNF-α, IL-6, MMP-2 and MMP-9 by RT-PCR analysis. Administration of ISO to rats significantly distorted their lipid metabolism and augmented inflammatory process, MMP expression and proteolytic activity. In addition, pretreatment with BCA of ISO-induced MI rats significantly reestablished the altered lipid metabolism and concealed the inflammation of cytokines. BCA suppressed the expressions of proinflammatory cytokines and MMPs in ISO-induced MI in rats when compared to normal untreated MI rats. Hence, these results established that BCA could improve the pathological processes of myocardial remodeling which was confirmed by histopathology of heart in MI rats and might be an effective beneficial ingredient for the management of heart failure disorders.

miR-145-5p attenuates inflammatory response and apoptosis in myocardial ischemia-reperfusion injury by inhibiting (NADPH) oxidase homolog 1

Myocardial ischemia-reperfusion (I/R) injury is a common complication following reperfusion therapy that involves a series of immune or apoptotic reactions. Studies have revealed the potential roles of miRNAs in I/R injury. Herein, we established a myocardial I/R model in rats and a hypoxia/reoxygenation (H/R) model in H9c2 cells and investigated the effect of miR-145-5p on myocardial I/R injury. After 3 h or 24 h of reperfusion, left ventricular end-systolic pressure (LVESP), ejection fraction (EF), and fractional shortening (FS) were obviously decreased, and left ventricular end-diastolic pressure (LVEDP) was increased. Meanwhile, I/R induced an increase in myocardial infarction area. Moreover, a decrease in miR-145-5p and increase in (NADPH) oxidase homolog 1 (NOH-1) were observed following I/R injury. With this in mind, we performed a luciferase reporter assay and demonstrated that miR-145-5p directly bound to NOH-1 3' untranslated region (UTR). Furthermore, miR-145-5p mimics decreased the levels of tumor necrosis factor (TNF)-α, IL-1β, and IL-6 via oxygen and glucose deprivation/reperfusion (OGD/R) stimulation. Upregulation of miR-145-5p increased cell viability and reduced apoptosis accompanied by downregulation of Bax, cleaved caspase-3, cleaved poly(ADP-ribose) polymerase (PARP) and upregulation of Bcl2. In addition, miR-145-5p overexpression increased superoxide dismutase (SOD) activity and reduced reactive oxygen species (ROS) and malondialdehyde (MDA) content under OGD/R stress. Notably, NOH-1 could significantly abrogate the above effects, suggesting that it is involved in miR-145-5p-regulated I/R injury. In summary, our findings indicated that miR-145-5p/NOH-1 has a protective effect on myocardial I/R injury by inhibiting the inflammatory response and apoptosis.

A double-edged sword of immuno-microenvironment in cardiac homeostasis and injury repair

The response of immune cells in cardiac injury is divided into three continuous phases: inflammation, proliferation and maturation. The kinetics of the inflammatory and proliferation phases directly influence the tissue repair. In cardiac homeostasis, cardiac tissue resident macrophages (cTMs) phagocytose bacteria and apoptotic cells. Meanwhile, NK cells prevent the maturation and transport of inflammatory cells. After cardiac injury, cTMs phagocytose the dead cardiomyocytes (CMs), regulate the proliferation and angiogenesis of cardiac progenitor cells. NK cells prevent the cardiac fibrosis, and promote vascularization and angiogenesis. Type 1 macrophages trigger the cardioprotective responses and promote tissue fibrosis in the early stage. Reversely, type 2 macrophages promote cardiac remodeling and angiogenesis in the late stage. Circulating macrophages and neutrophils firstly lead to chronic inflammation by secreting proinflammatory cytokines, and then release anti-inflammatory cytokines and growth factors, which regulate cardiac remodeling. In this process, dendritic cells (DCs) mediate the regulation of monocyte and macrophage recruitment. Recruited eosinophils and Mast cells (MCs) release some mediators which contribute to coronary vasoconstriction, leukocyte recruitment, formation of new blood vessels, scar formation. In adaptive immunity, effector T cells, especially Th17 cells, lead to the pathogenesis of cardiac fibrosis, including the distal fibrosis and scar formation. CMs protectors, Treg cells, inhibit reduce the inflammatory response, then directly trigger the regeneration of local progenitor cell via IL-10. B cells reduce myocardial injury by preserving cardiac function during the resolution of inflammation.

Donor heart preservation with hypoxic-conditioned medium-derived from bone marrow mesenchymal stem cells improves cardiac function in a heart transplantation model

Background

In heart transplantation, donor hearts inevitably suffer from ischemia/reperfusion (I/R) injury, which leads to primary graft dysfunction and affects patients’ survival rate. Bone marrow mesenchymal stem cells (BMSCs) have been reported to attenuate myocardial I/R injury via their paracrine effects, which can be enhanced by hypoxic preconditioning. We hypothesized that the donor heart preservation with hypoxic conditioned medium (CdM) derived from BMSCs would improve post-transplant graft function.

Methods

Normoxic or hypoxic CdM were isolated from rat BMSCs cultured under normoxic (20% O₂) or hypoxic (1% O₂) condition. Donor hearts were explanted; stored in cardioplegic solution supplemented with either a medium (vehicle), normoxic CdM (N-CdM), or hypoxic CdM (H-CdM); and then heterotopically transplanted. Antibody arrays were performed to compare the differences between hypoxic and normoxic CdM.

Results

After heart transplantation, the donor heart preservation with normoxic CdM was associated with a shorter time to return of spontaneous contraction and left ventricular systolic diameter, lower histopathological scores, higher ejection fraction, and fractional shortening of the transplanted hearts. The cardioprotective effects may be associated with the inhibition of apoptosis and inflammation, as reflected by less TUNEL-positive cells and lower levels of plasma proinflammatory cytokines (interleukin-1β, interleukin-6, tumor necrosis factor-α) and cardiac troponin I in the N-CdM group compared with the vehicle group. These therapeutic effects can be further enhanced by hypoxic preconditioning. Antibody arrays revealed that nine proteins were significantly increased in hypoxic CdM compared with normoxic CdM. Furthermore, compared with vehicle and N-CdM groups, the protein levels of PI3K and p-Akt/Akt ratio in the transplanted hearts significantly increased in the H-CdM group. However, no significant difference was found in the phosphorylation of Smad2 and Smad3 for the donor hearts among the three groups.

Conclusions

Our results indicate that the cardioplegic solution-enriched with hypoxic CdM can be a novel and promising preservation solution for donor hearts.

Inflammatory Cytokines and Chemokines as Therapeutic Targets in Heart Failure

Heart failure exhibits remarkable pathophysiologic heterogeneity. A large body of evidence suggests that regardless of the underlying etiology, heart failure is associated with induction of cytokines and chemokines that may contribute to the pathogenesis of adverse remodeling, and systolic and diastolic dysfunction. The pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-6 have been extensively implicated in the pathogenesis of heart failure. Inflammatory cytokines modulate phenotype and function of all myocardial cells, suppressing contractile function in cardiomyocytes, inducing inflammatory activation in macrophages, stimulating microvascular inflammation and dysfunction, and promoting a matrix-degrading phenotype in fibroblasts. Moreover, cytokine-induced growth factor synthesis may exert chronic fibrogenic actions contributing to the pathogenesis of heart failure with preserved ejection fraction (HFpEF). In addition to their role in adverse cardiac remodeling, some inflammatory cytokines may also exert protective actions on cardiomyocytes under conditions of stress. Chemokines, such as CCL2, are also upregulated in failing hearts and may stimulate recruitment of pro-inflammatory leukocytes, promoting myocardial injury, fibrotic remodeling, and dysfunction. Although experimental evidence suggests that cytokine and chemokine targeting may hold therapeutic promise in heart failure, clinical translation remains challenging. This review manuscript summarizes our knowledge on the role of TNF-α, IL-1, IL-6, and CCL2 in the pathogenesis of heart failure, and discusses the promises and challenges of targeted anti-cytokine therapy. Dissection of protective and maladaptive cellular actions of cytokines in the failing heart, and identification of patient subsets with overactive or dysregulated myocardial inflammatory responses are required for design of successful therapeutic approaches.

Identification of potential molecular mechanisms and small molecule drugs in myocardial ischemia/reperfusion injury

Myocardial ischemia/reperfusion (MI/R) injury is a complex phenomenon that causes severe damage to the myocardium. However, the potential molecular mechanisms of MI/R injury have not been fully clarified. We identified potential molecular mechanisms and therapeutic targets in MI/R injury through analysis of Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were found between MI/R injury and normal samples, and overlapping DEGs were found between GSE61592 and GSE67308. Gene Ontology (GO) and pathway analysis were performed for overlapping DEGs by Database for Annotation, Visualization and Integration Discovery (DAVID). Then, a network of protein-protein interaction (PPI) was constructed through the Search Tool for the Retrieval of Interacting Genes (STRING) database. Potential microRNAs (miRNAs) and therapeutic small molecules were screened out using microRNA.org database and the Comparative Toxicogenomics database (CTD), respectively. Finally, we identified 21 overlapping DEGs related to MI/R injury. These DEGs were significantly enriched in IL-17 signaling pathway, cytosolic DNA-sensing pathway, chemokine signaling, and cytokine-cytokine receptor interaction pathway. According to the degree in the PPI network, CCL2, LCN2, HP, CCL7, HMOX1, CCL4, and S100A8 were found to be hub genes. Furthermore, we identified potential miRNAs (miR-24-3p, miR-26b-5p, miR-2861, miR-217, miR-4251, and miR-124-3p) and therapeutic small molecules like ozone, troglitazone, rosiglitazone, and n-3 polyunsaturated fatty acids for MI/R injury. These results identified hub genes and potential small molecule drugs, which could contribute to the understanding of molecular mechanisms and treatment for MI/R injury.

Chemokines in Myocardial Infarction

In the infarcted myocardium, cardiomyocyte necrosis triggers an intense inflammatory reaction that not only is critical for cardiac repair, but also contributes to adverse remodeling and to the pathogenesis of heart failure. Both CC and CXC chemokines are markedly induced in the infarcted heart, bind to endothelial glycosaminoglycans, and regulate leukocyte trafficking and function. ELR+ CXC chemokines (such as CXCL8) control neutrophil infiltration, whereas CC chemokines (such as CCL2) mediate recruitment of mononuclear cells. Moreover, some members of the chemokine family (such as CXCL10 and CXCL12) may mediate leukocyte-independent actions, directly modulating fibroblast and vascular cell function. This review manuscript discusses our understanding of the role of the chemokines in regulation of injury, repair, and remodeling following myocardial infarction. Although several chemokines may be promising therapeutic targets in patients with myocardial infarction, clinical implementation of chemokine-based therapeutics is hampered by the broad effects of the chemokines in both injury and repair.

Berberine attenuates mitochondrial dysfunction by inducing autophagic flux in myocardial hypoxia/reoxygenation injury

Berberine (BBR) is routinely prescribed in many Asian countries to treat diarrhea. Evidence from both animal and clinical investigations suggests that BBR exerts diverse pharmacological activities, including antidiabetic, antineoplastic, antihypertensive, and antiatherosclerotic effects. This study aimed to explore the cardioprotective mechanisms of BBR and to elucidate the modulations between autophagy and mitochondrial function during hypoxia/reoxygenation (H/R) in H9c2 cells. The degree of autophagic flux was assessed by pretreating H9c2 cells with BBR prior to H/R exposure and measuring the expression levels of Beclin-1 and green fluorescent protein (GFP)-labeled LC3B fusion proteins as well as the LC3II/LC3I ratio. The mitochondrial membrane potential (△Ψm) in H9c2 cells was evaluated by detecting rhodamine-123 fluorescence using flow cytometry. The results revealed that pretreatment with BBR upregulated autophagic flux and protected against the loss of the △Ψm in H9c2 cells subjected to H/R. We conclude that BBR attenuates mitochondrial dysfunction by inducing autophagic flux.

MCP-1 mediates ischemia-reperfusion-induced cardiomyocyte apoptosis via MCPIP1 and CaSR

Monocyte chemotactic protein-1 (MCP-1) plays a crucial role in ischemia-reperfusion (I/R) injury; however, the detailed mechanism of MCP-1 in I/R injury-induced cardiomyocyte apoptosis remains unclear. In this study, we explored the cascade downstream of I/R-induced MCP-1 that modulates cell apoptosis and determined whether Ca²⁺-sensing receptors (CaSRs) are involved in the process. Protein levels were detected in a cardiac muscle cell line (HL-1) and primary cultured neonatal mouse ventricular cardiomyocytes using Western blotting and immunocytochemistry. Released MCP-1 was detected using ELISA. Both Hoechst staining and flow cytometry methods were used to measure cell apoptosis. Specific pharmacological inhibitors of CC chemokine receptor 2 (RS-102895) and CaSR (NPS-2143) as well as a CaSR activator (evocalcet) were applied to confirm the roles of these factors in I/R-induced cell apoptosis. I/R inhibited cell viability and upregulated cell apoptosis. Moreover, I/R induced the release of MCP-1 from both HL-1 cells and primary cardiomyocytes. Further research confirmed that CaSR acted as an upstream effector of monocyte chemotactic protein-1-induced protein-1 (MCPIP1) and coordinately regulated cell apoptosis, which was verified by addition of an inhibitor or activator of CaSR. Moreover, MCPIP1 induced cell apoptosis through endoplasmic reticulum (ER) stress but not autophagy induced by I/R. Based on these findings, I/R-induced MCP-1 release regulates cardiomyocyte apoptosis via the MCPIP1 and CaSR pathways, suggesting a new therapeutic strategy for I/R injury.NEW & NOTEWORTHY Ischemia-reperfusion (I/R)-induced monocyte chemotactic protein-1 release regulates cardiomyocyte apoptosis via the monocyte chemotactic protein-1-induced protein-1 (MCPIP1) and Ca²⁺-sensing receptor pathway. The functional changes mediated by MCPIP1 involve the activation of endoplasmic reticulum stress, but not the autophagy pathway, after I/R injury.

Immune response mediates the cardiac damage after subarachnoid hemorrhage

Cardiac dysfunction is a common adverse effect of subarachnoid hemorrhage (SAH). Autopsy of SAH patients shows immunocyte infiltration into the heart. In this study, a SAH model of endovascular perforation was performed in adult male mice in order to test whether SAH causes cardiac dysfunction in non-primary cardiac disease young adult male mice and whether immune response mediates SAH induced cardiac and neurological deficit. Splenectomy was performed on a subpopulation of mice one week prior to induction of the SAH. Neurological functional tests, transthoracic Doppler echocardiography, immunofluorescent staining, and flow cytometry were performed to investigate neurological and cardiac function and immune/inflammatory effects of SAH in mice with or without splenectomy. We found that SAH significantly induces ventricular fibrillation and cardiac dysfunction identified by significantly reduced left ventricular ejection fraction, left ventricular fractional shortening, decreased heart rate, as well as increased macrophage and neutrophil infiltration into heart and inflammatory factor expression in the heart compared to sham control mice. SAH also induces neurological deficit, increases astrocyte and microglial activity, and inflammatory cell infiltration into brain as well as up-regulates inflammatory factor expression in the brain tissue. Splenectomy not only significantly improves neurological function, but also reduces cardiac dysfunction compared to SAH alone mice. Splenectomy in SAH mice significantly reduces inflammatory cell infiltration, and decreases NADPH oxidase-2 and macrophage chemokine protein-1 expression in heart and brain when compared to non-splenectomy SAH mice. Our data suggest that, SAH induces acute cardiac dysfunction in non-primary cardiac disease mice. Secondary immune response may play an important role in mediating brain-heart damage after SAH.

Pegfilgrastim and linagliptin potentiate chemoattraction of Ccr2 and Cd44 stem cells accompanied by alterations of cardiac Hgf, Igf-1 and Mcp-1 in daunorubicin cardiomyopathy

Objective

Daunorubicin (DAU) downregulates cytokines promoting stem cell migration and homing into the heart, reducing cardiac regeneration after anticancer chemotherapy. Pegfilgrastim (PFIL) protects from DAU-induced neutropenia but its cardioprotective potential remains unclear. We tested whether pegfilgrastim and a dipeptidyl peptidase-4 inhibitor linagliptin, potential enhancers of stem cells migration and homing, would improve DAU-cardiomyopathy.

Methods

DAU (7.5 mg/kg, i.v.) was administered to male Wistar rats to induce cardiotoxicity. Pegfilgrastim (100 µg/kg, s.c.) was administered 24h after DAU, and linagliptin was administered orally for 8 weeks (5 mg/kg/day, LINA). Cardiac damage markers (Nppa, Myh6, Myh7, Gp91phox), cytokines (Sdf-1alpha, Mcp-1, Vegf, Hgf, Igf-1), stem cell markers (Cxcr4, Ccr2, Cd34, Cd133, Cd44, Cd105) were determined by qRT-PCR.

Key findings

Decreased Myh6, elevated Myh7 Nppa, and Gp91phox were not ameliorated by PFIL + LINA. Downregulated expressions of cytokines (Vegf, Sdf-1alpha) and stem cells markers (Cxcr4, Cd34, Cd133, and Cd105) remained decreased after PFIL + LINA. DAU-induced upregulation of Mcp-1, Ccr2 and Cd44 was further potentiated by PFIL + LINA. PFIL + LINA normalised expression of Hgf and Igf-1.

Conclusions

Although PFIL + LINA failed in universal potentiation of stem cells migration and homing, the expression of stem cell markers Ccr2 and Cd44 in the heart potentially increased through the preservation of Hgf, Igf-1 and upregulation of Mcp-1.

Translational overview of cytokine inhibition in acute myocardial infarction and chronic heart failure

Many cytokines are currently under investigation as potential target to improve cardiac function and outcome in the setting of acute myocardial infarction (MI) or chronic heart failure (HF). Here we aim to provide a translational overview of cytokine inhibiting therapies tested in experimental models and clinical studies. In various experimental studies, inhibition of interleukin-1 (IL-1), -6 (IL-6), -8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), CC- and CXC chemokines, and tumor necrosis factor-α (TNF-α) had beneficial effects on cardiac function and outcome. On the other hand, neutral or even detrimental results have been reported for some (IL-1, IL-6, IL-8, and MCP-1). Ambivalence of cytokine function, differences in study designs, treatment regimens and chosen endpoints hamper the translation of experimental research into clinical practice. Human studies are currently limited to IL-1β inhibition, IL-1 receptor antagonists (IL-1RA), IL-6 receptor antagonists (IL-6RA) or TNF inhibition. Despite favorable effects on cardiovascular events observed in retrospective cohort studies of rheumatoid arthritis patients treated with TNF inhibition or IL-1RA, most prospective studies reported disappointing and inconsistent results. Smaller studies (n < 100) generally reported favorable results of anticytokine therapy on cardiac function, but only one of the larger studies (n > 100) evaluating IL-1β inhibition presented positive results on outcome. In conclusion, of the 10 anticytokine therapies tested in animals models beneficial effects have been reported in at least one setting. In larger clinical studies, findings were unsatisfactory in all but one. Many anticytokine therapies with promising animal experimental data continue to require further evaluation in humans.

The Biological Basis for Cardiac Repair After Myocardial Infarction: From Inflammation to Fibrosis

In adult mammals, massive sudden loss of cardiomyocytes after infarction overwhelms the limited regenerative capacity of the myocardium, resulting in the formation of a collagen-based scar. Necrotic cells release danger signals, activating innate immune pathways and triggering an intense inflammatory response. Stimulation of toll-like receptor signaling and complement activation induces expression of proinflammatory cytokines (such as interleukin-1 and tumor necrosis factor-α) and chemokines (such as monocyte chemoattractant protein-1/ chemokine (C-C motif) ligand 2 [CCL2]). Inflammatory signals promote adhesive interactions between leukocytes and endothelial cells, leading to extravasation of neutrophils and monocytes. As infiltrating leukocytes clear the infarct from dead cells, mediators repressing inflammation are released, and anti-inflammatory mononuclear cell subsets predominate. Suppression of the inflammatory response is associated with activation of reparative cells. Fibroblasts proliferate, undergo myofibroblast transdifferentiation, and deposit large amounts of extracellular matrix proteins maintaining the structural integrity of the infarcted ventricle. The renin-angiotensin-aldosterone system and members of the transforming growth factor-β family play an important role in activation of infarct myofibroblasts. Maturation of the scar follows, as a network of cross-linked collagenous matrix is formed and granulation tissue cells become apoptotic. This review discusses the cellular effectors and molecular signals regulating the inflammatory and reparative response after myocardial infarction. Dysregulation of immune pathways, impaired suppression of postinfarction inflammation, perturbed spatial containment of the inflammatory response, and overactive fibrosis may cause adverse remodeling in patients with infarction contributing to the pathogenesis of heart failure. Therapeutic modulation of the inflammatory and reparative response may hold promise for the prevention of postinfarction heart failure.

Emerging importance of chemokine receptor CXCR3 and its ligands in cardiovascular diseases

The CXC chemokines, CXCL4, -9, -10, -11, CXCL4L1, and the CC chemokine CCL21, activate CXC chemokine receptor 3 (CXCR3), a cell-surface G protein-coupled receptor expressed mainly by Th1 cells, cytotoxic T (Tc) cells and NK cells that have a key role in immunity and inflammation. However, CXCR3 is also expressed by vascular smooth muscle and endothelial cells, and appears to be important in controlling physiological vascular function. In the last decade, evidence from pre-clinical and clinical studies has revealed the participation of CXCR3 and its ligands in multiple cardiovascular diseases (CVDs) of different aetiologies including atherosclerosis, hypertension, cardiac hypertrophy and heart failure, as well as in heart transplant rejection and transplant coronary artery disease (CAD). CXCR3 ligands have also proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the development of adverse cardiac remodelling. The observation that several of the above-mentioned chemokines exert biological actions independent of CXCR3 provides both opportunities and challenges for developing effective drug strategies. In this review, we provide evidence to support our contention that CXCR3 and its ligands actively participate in the development and progression of CVDs, and may additionally have utility as diagnostic and prognostic biomarkers.

Monocytes and monocyte chemoattractant protein 1 (MCP-1) as early predictors of disease outcome in patients with cerebral ischemic stroke

In this study to identify prognostic biomarkers for ischemic stroke (IS) outcome, we monitored monocyte number and monocyte chemoattractant protein (MCP-1) concentration in peripheral blood of 44 patients with IS during the week following IS. According to the severity of IS, patients were allocated to three groups: patients with transient ischemic attack (TIA), patients with National Institute of Health Stroke Scale (NIHSS) score ≤ 12, and patients with NIHSS > 12. In patients with NIHSS > 12 statistically significant increased number of monocytes was observed on day 7. MCP-1 plasma concentration initially increased, decreased at day 3 in patients with NIHSS > 12 and increased and restored on day 7. A negative correlation between the number of monocytes and MCP-1 concentration was observed on day 3 after IS. Higher day-7 MCP-1 level was associated with higher modified Rankin Scale (mRS) value (indicating worse outcome) at 90 days post-IS in patients with NIHSS > 12. Our findings suggest that number of monocytes and plasma MCP-1 level could be clinical prognostic biomarkers as early predictors of disease outcome in patients with IS.

Decreased effectiveness of ischemic heart preconditioning in the state of chronic inflammation

There is growing evidence, that beneficial effects of ischemic heart preconditioning (IPC) may be lost or limited due to diabetes, hyperlipidemia, hypertension, atherosclerosis, heart failure and senility. It is plausible, that these conditions interfere with the biochemical pathways underlying the IPC response, but the detailed explanation is not clear. Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), monocyte chemotactic protein-1 (MCP-1), histamine and many other agents used in a single dose before prolonged ischemia mimic IPC. However prolonged exposure to preconditioning mimetics leads to tolerance (tachyphylaxis). In the state of such tolerance ischemic preconditioning is no longer protective. Studies suggest that diabetes, hyperlipidemia, hypertension, atherosclerosis, heart failure and older age are accompanied by increased plasma levels of pro-inflammatory cytokines, MCP-1 and other inflammatory mediators. Therefore, we raised the hypothesis, that the reported lack of benefits of IPC in the listed states may be due to tolerance to IPC developed during prolonged exposure of the myocardium to preconditioning mimetics.

Macrophage Differentiation from Monocytes Is Influenced by the Lipid Oxidation Degree of Low Density Lipoprotein

LDL plays an important role in atherosclerotic plaque formation and macrophage differentiation. However, there is no report regarding the oxidation degree of LDL and macrophage differentiation. Our study has shown that the differentiation into M1 or M2 macrophages is related to the lipid oxidation level of LDL. Based on the level of lipid peroxidation, LDL is classified into high-oxidized LDL (hi-oxLDL) and low-oxidized LDL (low-oxLDL). The differentiation profiles of macrophages were determined by surface receptor expression and cytokine secretion profiles. Low-oxLDL induced CD86 expression and production of TNF-α and IL-12p40 in THP-1 cells, indicating an M1 macrophage phenotype. Hi-oxLDL induced mannose receptor expression and production of IL-6 and monocyte chemoattractant protein-1, which mostly match the phenotype of M2 macrophages. Further supporting evidence for an M2 polarization by hi-oxLDL was the induction of LOX-1 in THP-1 cells treated with hi-oxLDL but not with low-oxLDL. Similar results were obtained in primary human monocytes. Therefore, our results strongly suggest that the oxidation degree of LDL influences the differentiation of monocytes into M1 or M2 macrophages and determines the inflammatory fate in early stages of atherosclerosis.

Monocyte Chemoattractant Protein-Induced Protein 1 (MCPIP1) Enhances Angiogenic and Cardiomyogenic Potential of Murine Bone Marrow-Derived Mesenchymal Stem Cells

The current evidence suggests that beneficial effects of mesenchymal stem cells (MSCs) toward myocardial repair are largely due to paracrine actions of several factors. Although Monocyte chemoattractant protein-induced protein 1 (MCPIP1) is involved in the regulation of inflammatory response, apoptosis and angiogenesis, whether MCPIP1 plays any role in stem cell-induced cardiac repair has never been examined. By employing retroviral (RV)-transduced overexpression of MCPIP1, we investigated the impact of MCPIP1 on viability, apoptosis, proliferation, metabolic activity, proteome, secretome and differentiation capacity of murine bone marrow (BM) - derived MSCs. MCPIP1 overexpression enhanced angiogenic and cardiac differentiation of MSCs compared with controls as indicated by elevated expression of genes accompanying angiogenesis and cardiomyogenesis in vitro. The proangiogenic activity of MCPIP1-overexpressing MSCs (MCPIP1-MSCs) was also confirmed by increased capillary-like structure formation under several culture conditions. This increase in differentiation capacity was associated with decreased proliferation of MCPIP1-MSCs when compared with controls. MCPIP1-MSCs also expressed increased levels of proteins involved in angiogenesis, autophagy, and induction of differentiation, but not adverse inflammatory agents. We conclude that MCPIP1 enhances endothelial and cardiac differentiation of MSCs. Thus, modulating MCPIP1 expression may be a novel approach useful for enhancing the immune-regulatory, anti-apoptotic, anti-inflammatory and regenerative capacity of BM-derived MSCs for myocardial repair and regeneration of ischemic tissues.

Progesterone protects endothelial cells after cerebrovascular occlusion by decreasing MCP-1- and CXCL1-mediated macrophage infiltration

The neuroprotective effects of progesterone after ischemic stroke have been established, but the role of progesterone in promoting cerebrovascular repair remains under-explored. Male Sprague-Dawley rats underwent transient middle cerebral artery occlusion (tMCAO) for 90 min followed by reperfusion for 3 days. Progesterone (8 mg/kg/day) was administered intraperitoneally at 1h after initial occlusion followed by subcutaneous injections at 6, 24 and 48 h post-occlusion. Rats were euthanized after 72 h and brain endothelial cell density and macrophage infiltration were evaluated within the cerebral cortex. We also assessed progesterone's ability to induce macrophage migration toward hypoxic/reoxygenated cultured endothelial cells. We found that progesterone treatment post-tMCAO protects ischemic endothelial cells from macrophage infiltration. We further demonstrate that infiltration of monocytes/macrophages can be induced by potent chemotactic factors such as monocyte chemoattractant protein-1 (MCP-1) and the chemokine ligand 1 (CXCL1), secreted by hypoxic/reoxygenated endothelial cells. Progesterone blunts secretion of MCP-1 and CXCL1 from endothelial cells after hypoxia/reoxygenation injury and decreases leukocyte infiltration. The treatment protects ischemic endothelial cells from macrophage infiltration and thus preserves vascularization after ischemic injury.

Tumour necrosis factor-α contributes to improved cardiac ischaemic tolerance in rats adapted to chronic continuous hypoxia

AIM

It has been demonstrated that tumour necrosis factor-alpha (TNF-α) via its receptor 2 (TNFR2) plays a role in the cardioprotective effects of preconditioning. It is also well known that chronic hypoxia is associated with activation of inflammatory response. With this background, we hypothesized that TNF-α signalling may contribute to the improved ischaemic tolerance of chronically hypoxic hearts.

METHODS

Adult male Wistar rats were kept either at room air (normoxic controls) or at continuous normobaric hypoxia (CNH; inspired O2 fraction 0.1) for 3 weeks; subgroups of animals were treated with infliximab (monoclonal antibody against TNF-α; 5 mg kg(-1), i.p., once a week). Myocardial levels of oxidative stress markers and the expression of selected signalling molecules were analysed. Infarct size (tetrazolium staining) was assessed in open-chest rats subjected to acute coronary artery occlusion/reperfusion.

RESULTS

CNH increased myocardial TNF-α level and expression of TNFR2; this response was abolished by infliximab treatment. CNH reduced myocardial infarct size from 50.8 ± 4.3% of the area at risk in normoxic animals to 35.5 ± 2.4%. Infliximab abolished the protective effect of CNH (44.9 ± 2.0%). CNH increased the levels of oxidative stress markers (3-nitrotyrosine and malondialdehyde), the expression of nuclear factor κB and manganese superoxide dismutase, while these effects were absent in infliximab-treated animals. CNH-elevated levels of inducible nitric oxide synthase and cyclooxygenase 2 were not affected by infliximab.

CONCLUSION

TNF-α plays a role in the induction of ischaemia-resistant cardiac phenotype of CNH rats, possibly via the activation of protective redox signalling.

Deficiency for the chemokine monocyte chemoattractant protein-1 aggravates tubular damage after renal ischemia/reperfusion injury

Temporal expression of chemokines is a crucial factor in the regulation of renal ischemia/reperfusion (I/R) injury and repair. Beside their role in the migration and activation of inflammatory cells to sites of injury, chemokines are also involved in other processes such as angiogenesis, development and migration of stem cells. In the present study we investigated the role of the chemokine MCP-1 (monocyte chemoattractant protein-1 or CCL2), the main chemoattractant for monocytes, during renal I/R injury. MCP-1 expression peaks several days after inducing renal I/R injury coinciding with macrophage accumulation. However, MCP-1 deficient mice had a significant decreased survival and increased renal damage within the first two days, i.e. the acute inflammatory response, after renal I/R injury with no evidence of altered macrophage accumulation. Kidneys and primary tubular epithelial cells from MCP-1 deficient mice showed increased apoptosis after ischemia. Taken together, MCP-1 protects the kidney during the acute inflammatory response following renal I/R injury.

Comparison of arrhythmogenicity and proinflammatory activity induced by intramyocardial or epicardial myoblast sheet delivery in a rat model of ischemic heart failure

Although cell therapy of the failing heart by intramyocardial injections of myoblasts to results in regenerative benefit, it has also been associated with undesired and prospectively fatal arrhythmias. We hypothesized that intramyocardial injections of myoblasts could enhance inflammatory reactivity and facilitate electrical cardiac abnormalities that can be reduced by epicardial myoblast sheet delivery. In a rat model of ischemic heart failure, myoblast therapy either by intramyocardial injections or epicardial cell sheets was given 2 weeks after occlusion of the coronary artery. Ventricular premature contractions (VPCs) were assessed, using an implanted three-lead electrocardiograph at 1, 7, and 14 days after therapy, and 16-point epicardial electropotential mapping (EEPM) was used to evaluate ventricular arrhythmogenicity under isoproterenol stress. Cardiac functioning was assessed by echocardiography. Both transplantation groups showed therapeutic benefit over sham therapy. However, VPCs were more frequent in the Injection group on day 1 and day 14 after therapy than in animals receiving epicardial or sham therapy (p < 0.05 and p < 0.01, respectively). EEPM under isoproterenol stress showed macroreentry at the infarct border area, leading to ventricular tachycardias in the Injection group, but not in the myoblast sheet- or sham-treated groups (p = 0.045). Both transplantation types modified the myocardial cytokine expression profile. In animals receiving epicardial myoblast therapy, selective reductions in the expressions of interferon gamma, interleukin (IL)-1β and IL12 were observed, accompanied by reduced infiltration of inflammatory CD11b- and CD68-positive leukocytes, compared with animals receiving myoblasts as intramyocardial injections. Intramyocardial myoblast delivery was associated with enhanced inflammatory and immunomodulatory reactivity and increased frequency of VPCs. In comparison to intramyocardial injection, the epicardial route may serve as the preferred method of skeletal myoblast transplantation to treat heart failure.

The duality of chemokines in heart failure

The failing human heart is a bustling network of intra- and inter-cellular signals and related processes attempting to coordinate a repair mechanism for the injured or diseased myocardium. While our understanding of signaling by mode of cytokines is well understood on a systemic level, we are only now coming to elucidate the role of cytokines in cardiac self-regulation. An increasing number of studies are showing now that cardiomyocytes themselves have not only the ability but also the mandate to produce signals, and play direct roles in how these signals are interpreted. One of the families of cytokines employed by distressed cardiac tissue are chemokines. By regulating the movement of pro-inflammatory cell types to sites of injury, we see now how the myocardium responds to stress. Herein we review the participation of these inflammatory mediators and explore the delicate balance between their protective roles and damaging functions.

Mouse monocyte chemoattractant protein 1 (MCP1) functions as a monomer

Monocyte chemoattractant protein 1 (MCP1) is an important chemoattractant for microglia. Rodent MCP1 carries a heavily glycosylated C-terminus, which has been predicted to increase local MCP1 concentration, promote MCP1 dimerization/oligomerization, and facilitate receptor engagement. Previous studies have shown that MCP1 mutant lacking the glycosylated C-terminus cannot dimerize/oligomerize, but has higher chemotactic potency than the wild-type (full-length) MCP1, suggesting that rodent MCP1 may function as a monomer. Although many groups support this hypothesis, there is no direct evidence on whether rodent MCP1 dimer is functional. In this paper, using forced recombinant dimeric MCP1 proteins we show that mouse MCP1 dimer is unable to activate Rac1, promote protrusion of lamellipodia, or induce microglial migration, although it can bind to CCR2 and mediate its internalization. These results support the idea that signaling events mediated by MCP1 require the presence of the monomeric form of this chemokine.

Parasite-derived neurotrophic factor/trans-sialidase of Trypanosoma cruzi links neurotrophic signaling to cardiac innate immune response

The Chagas' disease parasite Trypanosoma cruzi elicits a potent inflammatory response in acutely infected hearts that keeps parasitism in check and triggers cardiac abnormalities. A most-studied mechanism underlying innate immunity in T. cruzi infection is Toll-like receptor (TLR) activation by lipids and other parasite molecules. However, yet-to-be-identified pathways should exist. Here, we show that T. cruzi strongly upregulates monocyte chemoattractant protein 1 (MCP-1)/CCL2 and fractalkine (FKN)/CX3CL1 in cellular and mouse models of heart infection. Mechanistically, upregulation of MCP-1 and FKN stems from the interaction of parasite-derived neurotrophic factor (PDNF)/trans-sialidase with neurotrophic receptors TrkA and TrkC, as assessed by pharmacological inhibition, neutralizing antibodies, and gene silencing studies. Administration of a single dose of intravenous PDNF to naive mice results in a dose-dependent increase in MCP-1 and FKN in the heart and liver with pulse-like kinetics that peak at 3 h postinjection. Intravenous PDNF also augments MCP-1 and FKN in TLR signaling-deficient MyD88-knockout mice, underscoring the MyD88-independent action of PDNF. Although single PDNF injections do not increase MCP-1 and FKN receptors, multiple PDNF injections at short intervals up the levels of receptor transcripts in the heart and liver, suggesting that sustained PDNF triggers cell recruitment at infection sites. Thus, given that MCP-1 and FKN are chemokines essential to the recruitment of immune cells to combat inflammation triggers and to enhance tissue repair, our findings uncover a new mechanism in innate immunity against T. cruzi infection mediated by Trk signaling akin to an endogenous inflammatory and fibrotic pathway resulting from cardiomyocyte-TrkA recognition by matricellular connective tissue growth factor (CTGF/CCN2).

Monocyte chemoattractant protein-1 and the blood-brain barrier

The blood-brain barrier (BBB) is a dynamic structure that maintains the homeostasis of the brain and thus proper neurological functions. BBB compromise has been found in many pathological conditions, including neuroinflammation. Monocyte chemoattractant protein-1 (MCP1), a chemokine that is transiently and significantly up-regulated during inflammation, is able to disrupt the integrity of BBB and modulate the progression of various diseases, including excitotoxic injury and hemorrhage. In this review, we first introduce the biochemistry and biology of MCP1, and then summarize the effects of MCP1 on BBB integrity as well as individual BBB components.

Chronic treatment of mice with leukemia inhibitory factor does not cause adverse cardiac remodeling but improves heart function

Recent evidence suggests that the IL-6 family cytokine, leukemia inhibitory factor (LIF) is produced by cardiac cells under stress conditions including myocardial infarction and heart failure. Additionally, short-term delivery of LIF has been shown to have preconditioning effects on the heart and to limit infarct size. However, cell culture studies have suggested that LIF may exert harmful effects on cardiac myocytes, including pathological hypertrophy and contractile dysfunction. Long-term effects of LIF on the heart in vivo have not been reported and were the focus of this study. Adult male mice were injected daily with LIF (2 μg/30 g) or saline for 10 days. LIF treatment caused an approximate 11% loss in body weight. Cardiac function as assessed by echocardiography was improved in LIF-treated mice. Ejection fraction and fractional shortening were increased by 21% and 32%, respectively. No cardiac hypertrophy was seen on histology in LIF-treated mice,, there was no change in the heart-to-tibia length ratio, and no cardiac fibrosis was observed. STAT3 was markedly activated by LIF in the left ventricle. Different effects of LIF were seen in protein levels of genes associated with STAT3 in the left ventricle: levels of SOD2 and Bcl-xL were unchanged, but levels of total STAT3 and MCP-1 were increased. There was a trend towards increased expression of miR-17, miR-21, and miR-199 in the left ventricle of LIF-treated mice, but these changes were not statistically significant. In conclusion, effects of chronic LIF treatment on the heart, although modest, were positive for systolic function: adverse cardiac remodeling was not observed. Our findings thus lend further support to recent proposals that LIF may have therapeutic utility in preventing injury to or repairing the myocardium.

Lack of clinical therapeutic benefit of antidepressants is associated overall activation of the inflammatory system

Despite the evidence of an association between depression and increased inflammatory markers, still little is known in relation to the most severe cases of the disorder i.e., those who fail to respond to antidepressants. We have assessed the cytokine profile and cortisol levels in 21 healthy controls (HC) and 19 medicated patients with depression with treatment-resistance (TRD) moderately ill. As an initial exploratory analysis, we have also related cytokine profile to the patient's clinical treatment outcome after an inpatient admission. Cytokine profile was measured in the serum by the Cytokine Array I kit (Randox). Plasma cortisol was carried out using a commercially available for the IMMULITE system. When compared to healthy controls, depressed patients had higher levels of cortisol, IL-6, IL-10, but lower levels of IL-4 and VEGF. Our exploratory analysis showed subjects who did not go on to respond to the inpatient admission treatment package had lower levels of MCP-1, and a trend toward lower levels of VEGF. Taking together, these data suggest that lack of clinical therapeutic benefit of antidepressants is associated with overall activation of the inflammatory system.

The protective effect of picroside II against hypoxia/reoxygenation injury in neonatal rat cardiomyocytes

CONTEXT

Picroside II, an iridoid glucoside found in the root of Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been demonstrated to possess potent antioxidant activity. However, whether picroside II has a protective effect against hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury is poorly understood.

OBJECTIVE

To explore the cardioprotective role of picroside II against oxidative stress induced by H/R injury in neonatal rat cardiacmyocytes.

MATERIALS AND METHODS

The viability and cellular damage of cardiomyocytes were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolim bromide (MTT) and lactate dehydrogenase (LDH) assays, respectively. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), the levels of reduced (GSH) and oxidized glutathione (GSSG), and the contents of malondialdehyde (MDA) were determined by a colorimetric method. The levels of intracellular reactive oxygen species (ROS) and calcium were evaluated by flow cytometric analysis.

RESULTS

We analyzed the effective half-maximal concentration for protection from the dose-response curves and obtained the concentration of 50 µg/mL as EC(50). Pretreated cardiomyocytes with picroside II (50-200 µg/mL), prior to H/R exposure, inhibited LDH activity in culture media and increased cell viability in a dose-dependent manner. This protective effect was accompanied by significantly increasing reduced GSH contents and the activities of SOD and GSH-Px and attenuating MDA and GSSG contents in response to H/R injury. Furthermore, treatment with picroside II also inhibited ROS production and calcium accumulation in cardiomyocytes.

DISCUSSION AND CONCLUSION

The present study demonstrates that picroside II protects cardiomyocytes against oxidative-stress injury induced by H/R through reduction of ROS production and calcium accumulation and enhancement of the activity of antioxidant defense.

The effects of weekly augmentation therapy in patients with PiZZ α1-antitrypsin deficiency

Background

The major concept behind augmentation therapy with human α₁-antitrypsin (AAT) is to raise the levels of AAT in patients with protease inhibitor phenotype ZZ (Glu342Lys)-inherited AAT deficiency and to protect lung tissues from proteolysis and progression of emphysema.

Objective

To evaluate the short-term effects of augmentation therapy (Prolastin^®) on plasma levels of AAT, C-reactive protein, and chemokines/cytokines.

Materials and methods

Serum and exhaled breath condensate were collected from individuals with protease inhibitor phenotype ZZ AAT deficiency-related emphysema (n = 12) on the first, third, and seventh day after the infusion of intravenous Prolastin. Concentrations of total and polymeric AAT, interleukin-8 (IL-8), monocyte chemotactic protein-1, IL-6, tumor necrosis factor-α, vascular endothelial growth factor, and C-reactive protein were determined. Blood neutrophils and primary epithelial cells were also exposed to Prolastin (1 mg/mL).

Results

There were significant fluctuations in serum (but not in exhaled breath condensate) levels of AAT polymers, IL-8, monocyte chemotactic protein-1, IL-6, tumor necrosis factor-α, and vascular endothelial growth factor within a week of augmentation therapy. In general, augmented individuals had higher AAT and lower serum levels of IL-8 than nonaugmented subjects. Prolastin added for 3 hours to neutrophils from protease inhibitor phenotype ZZ individuals in vitro reduced IL-8 release but showed no effect on cytokine/chemokine release from human bronchial epithelial cells.

Conclusion

Within a week, augmentation with Prolastin induced fluctuations in serum levels of AAT polymers and cytokine/chemokines but specifically lowered IL-8 levels. It remains to be determined whether these effects are related to the Prolastin preparation per se or to the therapeutic efficacy of augmentation with AAT.

Cardiac intercellular communication: are myocytes and fibroblasts fair-weather friends?

The cardiac fibroblast (CF) has historically been thought of as a quiescent cell of the heart, passively maintaining the extracellular environment for the cardiomyocytes (CM), the functional cardiac cell type. The increasingly appreciated role of the CF, however, extends well beyond matrix production, governing many aspects of cardiac function including cardiac electrophysiology and contractility. Importantly, its contributions to cardiac pathophysiology and pathologic remodeling have created a shift in the field's focus from the CM to the CF as a therapeutic target in the treatment of cardiac diseases. In response to cardiac injury, the CF undergoes a pathologic phenotypic transition into a myofibroblast, characterized by contractile smooth muscle proteins and upregulation of collagens, matrix proteins, and adhesion molecules. Further, the myofibroblast upregulates expression and secretion of a variety of pro-inflammatory, profibrotic mediators, including cytokines, chemokines, and growth factors. These mediators act in both an autocrine fashion to further activate CFs, as well as in a paracrine manner on both CMs and circulating inflammatory cells to induce myocyte dysfunction and chronic inflammation, respectively. Together, cell-specific cytokine-induced effects exacerbate pathologic remodeling and progression to HF. A better understanding of this dynamic intercellular communication will lead to novel targets for the attenuation of cardiac remodeling. Current strategies aimed at targeting cytokines have been largely unsuccessful in clinical trials, lending insights into ways that such intercellular cross talk can be more effectively attenuated. This review will summarize the current knowledge regarding CF functions in the heart and will discuss the regulation and signaling behind CF-mediated cytokine production and function. We will then highlight clinical trials that have exploited cytokine cross talk in the treatment of heart failure and provide novel strategies currently under investigation that may more effectively target pathologic CF-CM communication for the treatment of cardiac disease. This review explores novel mechanisms to directly attenuate heart failure progression through inhibition of signaling downstream of pro-inflammatory cytokines that are elevated after cardiac injury.

Chemokines and their receptors in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating clinical event which results in a high rate of disability and death. At present, no effective treatment is available for ICH. Accumulating evidence suggests that inflammatory responses contribute significantly to the ICH-induced secondary brain outcomes. During ICH, inflammatory cells accumulate at the ICH site attracted by gradients of chemokines. This review summarizes recent progress in ICH studies and the chemoattractants that act during the injury and focuses on and introduces the basic biology of the chemokine monocyte chemoattractant protein-1 (MCP1) and its role in the progression of ICH. Better understanding of MCP1 signaling cascade and the compensation after its inhibition could shed light on the development of effective treatments for ICH.

Inflammation, endoplasmic reticulum stress, autophagy, and the monocyte chemoattractant protein-1/CCR2 pathway

Numerous inflammatory cytokines have been implicated in the pathogenesis of cardiovascular diseases. Monocyte chemoattractant protein (MCP)-1/CCL2 is expressed by mainly inflammatory cells and stromal cells such as endothelial cells, and its expression is upregulated after proinflammatory stimuli and tissue injury. MCP-1 can function as a traditional chemotactic cytokine and also regulates gene transcription. The recently discovered novel zinc-finger protein, called MCPIP (MCP-1-induced protein), initiates a series of signaling events that causes oxidative and endoplasmic reticulum (ER) stress, leading to autophagy that can result in cell death or differentiation, depending on the cellular context. After a brief review of the basic processes involved in inflammation, ER stress, and autophagy, the recently elucidated role of MCP-1 and MCPIP in inflammatory diseases is reviewed. MCPIP was found to be able to control inflammatory response by inhibition of nuclear factor-κB activation through its deubiquitinase activity or by degradation of mRNA encoding a set of inflammatory cytokines through its RNase activity. The potential inclusion of such a novel deubiquitinase in the emerging anti-inflammatory strategies for the treatment of inflammation-related diseases such as cardiovascular diseases and type 2 diabetes is briefly discussed.

MCP-1-induced protein attenuates endotoxin-induced myocardial dysfunction by suppressing cardiac NF-кB activation via inhibition of IкB kinase activation

Myocardial contractile dysfunction is a major consequence of septic shock, which is mainly mediated by nuclear factor-kappa B (NF-кB)-dependent production of inflammatory mediators in the heart. A novel zinc-finger protein, MCP-1-induced protein (MCPIP), is thought to have NF-кB inhibitory activity in certain cell cultures, but its pathophysiological consequence in vivo remains undefined. This study aims to clarify whether the anti-inflammatory potency of MCPIP contribute to amelioration of septic myocardial inflammation and dysfunction in vivo. Transgenic mice (TG) with cardiac-specific expression of MCPIP and their littermate wild-type (WT) controls were challenged with Escherichia coli LPS (10mg/kg ip) and myocardial function was assessed 18 h later using echocardiography. LPS administration markedly deteriorated myocardial contractile function evidenced by reduction of the percentage of left ventricular fractional shortening, which was significantly attenuated by myocardial expression of MCPIP. MCPIP TG mice exhibited a markedly reduced myocardial inflammatory cytokines, less of iNOS expression and peroxynitrite formation, decreased caspase-3/7 activities and apoptotic cell death compared with LPS-treated WT mice. Activation of cardiac NF-кB observed in LPS-challenged WT mice was suppressed by the presence of MCPIP, as evidenced by decreased phosphorylation of IкB kinase (IKKα/β), reduced degradation of the cytosolic IкBα, and decreased nuclear translocation of NF-кB p65 subunit and its target DNA-binding activity. These results suggest that MCPIP has therapeutic values to protect heart from inflammatory pathologies, possibly through inhibition of IкB kinase complex, leading to blockade of NF-кB activation, and subsequently, attenuation of the proinflammatory state and nitrosative stress in the myocardium.

Experimental Swine lung autotransplant model to study lung ischemia-reperfusion injury

INTRODUCTION

Ischemia-reperfusion (IR) lung injury has been investigated extensively on clinical and experimental models of cold ischemia. However, relatively few studies examine the detailed biochemical changes occurring during normothermic (warm) IR. The objective of this work was to establish an experimental lung autotransplant model to be carried out on pigs in order to study the early stages of normothermic lung IR. ANIMALS Y METHODS: Six Large-White pigs underwent a lung autotransplant which entailed left pneumonectomy, ex situ cranial lobectomy, caudal lobe reimplantation and its reperfusion for 30 min. Throughout the procedure, several parameters were measured in order to identify hemodynamic, gasometric and biochemical changes. Non-parametric statistical analyses were used to compare differences between periods.

RESULTS

After ischemia, a significant increase (P < 0.05) in lipid peroxidation metabolites, proinflammatory cytokines and chemokines (TNF-α, IL-1β y MCP-1), neutrophil activation, inducible nitric oxide synthase activity and protein-kinase MAPK p38 levels were observed in lung tissue. However, constitutive nitric oxide synthase activity in lung tissue and carbon monoxide plasma levels were decrease. The same held true throughout the reperfusion period, when an increase in the constitutive heme-oxygenase activity was also shown.

CONCLUSIONS

An experimental model of normothermic lung IR injury is presented and detailed changes in hemodynamic, gasometric and biochemical parameters are shown. Both the model and the studied parameters may be clinically useful in future investigations testing new therapies to prevent normothermic IR induced lung injury.

Truncation of monocyte chemoattractant protein 1 by plasmin promotes blood-brain barrier disruption

Previous studies have shown that plasmin cleaves monocyte chemoattractant protein 1 (MCP1; officially known as C-C motif chemokine 2, CCL2) at K104, and this cleavage enhances its chemotactic potency significantly. Accumulating evidence reveals that MCP1 also disrupts the integrity of the blood-brain barrier (BBB). Here, we show that K104Stop-MCP1, truncated at the K104 where plasmin would normally cleave, is more efficient than the full-length protein (FL-MCP1) in compromising the integrity of the BBB in in vitro and in vivo models. K104Stop-MCP1 increases the permeability of BBB in both wild-type mice and mice deficient for tissue plasminogen activator (tPA), which converts plasminogen into active plasmin, suggesting that plasmin-mediated truncation of MCP1 plays an important role in BBB compromise. Furthermore, we show that the mechanisms underlying MCP1-induced BBB disruption involve redistribution of tight junction proteins (occludin and ZO-1) and reorganization of the actin cytoskeleton. Finally, we show that the redistribution of ZO-1 is mediated by phosphorylation of ezrin-radixin-moesin (ERM) proteins. These findings identify plasmin as a key signaling molecule in the regulation of BBB integrity and suggest that plasmin inhibitors might be used to modulate diseases accompanied by BBB compromise.

Involvement of inflammatory chemokines in survival of human monocytes fed with malarial pigment

Hemozoin (HZ)-fed monocytes are exposed to strong oxidative stress, releasing large amounts of peroxidation derivatives with subsequent impairment of numerous functions and overproduction of proinflammatory cytokines. However, the histopathology at autopsy of tissues from patients with severe malaria showed abundant HZ in Kupffer cells and other tissue macrophages, suggesting that functional impairment and cytokine production are not accompanied by cell death. The aim of the present study was to clarify the role of HZ in cell survival, focusing on the qualitative and temporal expression patterns of proinflammatory and antiapoptotic molecules. Immunocytochemical and flow cytometric analyses showed that the long-term viability of human monocytes was unaffected by HZ. Short-term analysis by macroarray of a complete panel of cytokines and real-time reverse transcription (RT)-PCR experiments showed that HZ immediately induced interleukin-1β (IL-1β) gene expression, followed by transcription of eight additional chemokines (IL-8, epithelial cell-derived neutrophil-activating peptide 78 [ENA-78], growth-regulated oncogene α [GROα], GROβ, GROγ, macrophage inflammatory protein 1α [MIP-1α], MIP-1β, and monocyte chemoattractant protein 1 [MCP-1]), two cytokines (tumor necrosis factor alpha [TNF-α] and IL-1receptor antagonist [IL-1RA]), and the cytokine/chemokine-related proteolytic enzyme matrix metalloproteinase 9 (MMP-9). Furthermore, real-time RT-PCR showed that 15-HETE, a potent lipoperoxidation derivative generated by HZ through heme catalysis, recapitulated the effects of HZ on the expression of four of the chemokines. Intermediate-term investigation by Western blotting showed that HZ increased expression of HSP27, a chemokine-related protein with antiapoptotic properties. Taken together, the present data suggest that apoptosis of HZ-fed monocytes is prevented through a cascade involving 15-HETE-mediated upregulation of IL-1β transcription, rapidly sustained by chemokine, TNF-α, MMP-9, and IL-1RA transcription and upregulation of HSP27 protein expression.

The C terminus of mouse monocyte chemoattractant protein 1 (MCP1) mediates MCP1 dimerization while blocking its chemotactic potency

The extracellular protease plasmin cleaves mouse MCP1 (monocyte chemoattractant protein 1) at lysine 104, releasing a 50-amino acid C-terminal domain. The cleavage event increases the chemotactic activity of MCP1 and, by doing so, promotes the progression of excitotoxic injury in the central nervous system in pathological settings. The mechanism through which the cleavage event enhances MCP1-mediated chemoattraction is unknown; to investigate it, we use wild-type and mutant forms of recombinant MCP1. Full-length MCP1 (FL-MCP1) is secreted by cells as a dimer or multimer. We show that a mutant truncated at the C terminus, K104Stop-MCP1, does not dimerize, revealing that the C terminus mediates the interaction. MCP1 interacts with the monocyte/microglia receptor CCR2. The interaction is critical to the function of MCP1 because CCR2(-/-) microglia do not undergo chemotaxis in response to MCP1 stimulation. We show that stimulation of microglia with FL-MCP1 or K104Stop-MCP1 triggers CCR2 internalization, whereas a mutant form unable to be cleaved at lysine 104 (K104A-MCP1) is relatively ineffective in this assay, suggesting that the C-terminal region interferes with the MCP1-CCR2 interaction. Moreover, FL-MCP1 and K104Stop-MCP1 stimulation leads to activation of Rac1, a small GTPase involved in cell migration. Conversely, MCP1-stimulated microglial migration is blocked by the Rac1 inhibitor, NSC23766, demonstrating the requirement for Rac1 effector pathways in this response. Taken together, we propose a model for MCP1 localization, activation, and function based on the initial presence and then removal of its C terminus, coupled with a requisite downstream signaling pathway from CCR2 stimulation to Rac1 activation.