Chemokine expression in myocardial ischemia: MIP-2 dependent MCP-1 expression protects cardiomyocytes from cell death

Heart Scar-In-A-Dish: Tissue Culture Platform to Study Myocardial Infarct Healing In Vitro

Myocardial Infarction (MI) is a major contributor to morbidity and mortality, wherein blood flow is blocked to a portion of the left ventricle and leads to myocardial necrosis and scar formation. Cardiac remodeling in response to MI is a major determinant of patient prognosis, so many therapies are under development to improve infarct healing. Part of this development involves in vitro therapy screening which can be accelerated by engineered heart tissues (EHTs). Unfortunately, EHTs often over-simplify the infarcted tissue microarchitecture by neglecting spatial variation found in infarcted ventricles. MI results in a spatially heterogeneous environment with an infarct zone composed mostly of extracellular matrix (ECM) and cardiac fibroblasts, contrasted with a remote (non-infarct) zone composed mostly of cardiomyocytes, and a border zone transitioning in between. The heterogeneous structure is accompanied by heterogeneous mechanics where the passive infarct zone is cyclically stretched under tension as the remote zone cyclically contracts with every heartbeat. We present an in vitro 3-dimensional tissue culture platform focused on mimicking the heterogeneous mechanical environment of post-infarct myocardium. Herein, EHTs were subjected to a cryowound injury to induce localized cell death in a central portion of beating tissues composed of neonatal rat cardiomyocytes and cardiac fibroblasts. After injury, the remote zone continued to contract (i.e., negative strains) while the wounded zone was cyclically stretched (i.e., positive tensile strains) with intermediate strains in the border zone. We also observed increased tissue stiffnesses in the wounded zone and border zone following injury, while the remote zone did not show the same stiffening. Collectively, this work establishes a novel in vitro platform for characterizing myocardial wound remodeling with both spatial and temporal resolution, contributing to a deeper understanding of MI and offering insights for potential therapeutic approaches.

Circulating monocyte adhesion repairs endothelium-denuded injury through downstream of kinase 3-mediated endothelialization

The integrity of the endothelial monolayer is critical for preventing life-threatening hemorrhaging and thrombosis. However, how severe endothelium-denuded injury is rapidly repaired remains unknown. Given the common biological properties between endothelial cells and circulating monocytes, we aimed to examine whether blood monocytes are involved in endothelium wound healing. The in vivo common carotid artery endothelium-denuded (CCAED) model was established through a wire-induced injury. Monocyte adhesion was assessed using immunofluorescence and a parallel plate flow chamber. We initially observed that the circulating monocyte-mediated endothelialization was better downstream of kinase 3 deficient mice (DOK3-/-) than that of wild-type (WT) mice following induction of the CCAED model. Rapid endothelialization increased endothelial integrity, prevented coagulation, and decreased thrombosis. Mechanistically, following endothelium-denuded injury, monocyte chemoattractant protein 1 (MCP1) disassociated from DOK3 and C-C chemokine receptor type 2B (CCR2B), increased the intracellular Ca2+ concentration, and promoted adhesion in circulating monocytes. However, this process was inhibited by the CCR2B inhibitor INCB3344. Moreover, the adhesive functions of circulating monocytes isolated from DOK3-/- mice were stronger than those from WT mice. Furthermore, adhered monocytes expressed endothelial-specific markers and compensated for endothelium-dependent vasorelaxation in WT mice. Similarly, these effects were enhanced in DOK3-/- mice. Bindarit, a selective MCP1 inhibitor, suppressed endothelialization following CCAED surgery in WT mice but not in DOK3-/- mice. In conclusion, endothelialization mediated by circulating monocytes repairs endothelium-denuded injury to compensate for endothelial functions through MCP1/DOK3/CCR2B/Ca2+ signaling. Our findings indicate that circulating monocyte adhesion is an important endothelial wound healing mechanism.

Regulatory effects of statins on CCL2/CCR2 axis in cardiovascular diseases: new insight into pleiotropic effects of statins

BACKGROUND

HMG-CoA reductase inhibitors are well-known medications in the treatment of cardiovascular disorders due to their pleiotropic and lipid-lowering properties. Herein, we reviewed the effects of statins on the CCL2/CCR2 axis.

METHOD

Scopus and Pubmed databases were systematically searched using the following keywords:" Hydroxymethylglutaryl CoA Reductase Inhibitors"," HMG-CoA Reductase Inhibitors"," Statins", "CCL2, Chemokine", "Monocyte Chemoattractant Protein-1" and "Chemokine (C-C Motif) Ligand 2". Evidence investigating the role of statin on MCP-1 in CVD was identified and bibliographies were completely evaluated to gather further related studies.

RESULTS

The anti-inflammatory effects of statins on the CCL2/CCR2 pathway have been widely investigated. Despite inconclusive results, a great body of research supports the regulatory roles of statins on this pathway due to their pleiotropic effects. By disrupting the CCL2/CCR2 axis, statins attenuate the infiltration of monocytes and macrophages into the zone of inflammation and hence down-regulate the inflammatory cascades in various CVDs including atherosclerosis, cardiac remodeling, and stroke, among others.

CONCLUSION

CCL2 plays a major role in the pathogenesis of cardiovascular disorders. Down-regulation of CCL2 is proposed as one of the pleiotropic properties of statins. However, more investigations are required to elucidate which statin in what dose exerts a more potent effect on CCL2/CCR2 pathway.

Progranulin deficiency exacerbates cardiac remodeling after myocardial infarction

Myocardial infarction (MI) is a lethal disease that causes irreversible cardiomyocyte death and subsequent cardiovascular remodeling. We have previously shown that the administration of recombinant progranulin (PGRN) protects against myocardial ischemia and reperfusion injury. However, the post-MI role of PGRN remains unclear. In the present study, we investigated the effects of PGRN deficiency on cardiac remodeling after MI. Wild-type and PGRN-knockout mice were subjected to MI by ligation of the left coronary artery for histological, electrophysiological, and protein expression analysis. Cardiac macrophage subpopulations were analyzed by flow cytometry. Bone marrow-derived macrophages (BMDMs) were acquired and treated with LPS + IFN-γ and IL-4 to evaluate mRNA levels and phagocytic ability. PGRN expression was gradually increased in the whole heart at 1, 3, and 7 days after MI. Macrophages abundantly expressed PGRN at the border areas at 3 days post-MI. PGRN-knockout mice showed higher mortality, increased LV fibrosis, and severe arrhythmia following MI. PGRN deficiency increased the levels of CD206 and MerTK expression and macrophage infiltration in the infarcted myocardium, which was attributed to a larger subpopulation of cardiac CCR2+ Ly6Clow CD11b+ macrophages. PGRN-deficient BMDMs exhibited higher TGF-β, IL-4R, and lower IL-1β, IL-10 and increased acute phagocytosis following stimulation of LPS and IFN-γ. PGRN deficiency reduced survival and increased cardiac fibrosis following MI with the induction of abnormal subpopulation of cardiac macrophages early after MI, thereby providing insight into the relationship between properly initiating cardiac repair and macrophage polarization after MI.

XCR1+ conventional dendritic cell-induced CD4+ T helper 1 cell activation exacerbates cardiac remodeling after ischemic myocardial injury

Cardiac remodeling has no established therapies targeting inflammation. CD4⁺ T-cell subsets have been reported to play significant roles in healing process after ischemic myocardial injury, but their detailed mechanisms of activation remain unknown. To explore immune reactions during cardiac remodeling, we applied a non-surgical model of coronary heart disease (CHD) induced by a high-fat diet (HFD-CHD) in SR-BI^-/-/ApoeR61^h/h mice. Flow cytometry analyses throughout the period of progressive cardiac dysfunction revealed that CD4⁺ T Helper 1 (Th1) cells were predominantly activated in T-cell subsets. Probucol was reported to attenuate cardiac dysfunction after coronary artery ligation model (ligation-MI) in rats. To determine whether probucol suppress cardiac remodeling after HFD-CHD, we treated SR-BI^-/-/ApoeR61^h/h mice with probucol. We found treatment with probucol in HFD-CHD mice reduced cardiac dysfunction, with attenuated activation of Th1 cells. RNA-seq analyses revealed that probucol suppressed the expression of CXCR3, a Th1-related chemokine receptor, in the heart. XCR1⁺ cDC1 cells, which highly expresses the CXCR3 ligands CXCL9 and CXCL10, were predominantly activated after HFD-CHD. XCR1⁺ cDC1 lineage skewing of pre-DC progenitors was observed in bone marrow, with subsequent systemic expansion of XCR1⁺ cDC1 cells after HFD-CHD. Activation of CXCR3⁺ Th1 cell and XCR1⁺ cDC1 cells was also observed in ligation-MI. Notably, post-MI depletion of XCR1⁺ cDC1 cells suppressed CXCR3⁺ Th1 cell activation and prevented cardiac dysfunction. In patient autopsy samples, CXCR3⁺ Th1 and XCR1⁺ cDC1 cells infiltrated the infarcted area. In this study, we identified a critical role of XCR1⁺ cDC1-activated CXCR3⁺ Th1 cells in ischemic cardiac remodeling.

Macrophages in myocardial infarction

The heart contains a population of resident macrophages that markedly expands following injury through recruitment of monocytes and through proliferation of macrophages. In myocardial infarction, macrophages have been implicated in both injurious and reparative responses. In coronary atherosclerotic lesions, macrophages have been implicated in disease progression and in the pathogenesis of plaque rupture. Following myocardial infarction, resident macrophages contribute to initiation and regulation of the inflammatory response. Phagocytosis and efferocytosis are major functions of macrophages during the inflammatory phase of infarct healing, and mediate phenotypic changes, leading to acquisition of an anti-inflammatory macrophage phenotype. Infarct macrophages respond to changes in the cytokine content and extracellular matrix composition of their environment and secrete fibrogenic and angiogenic mediators, playing a central role in repair of the infarcted heart. Macrophages may also play a role in scar maturation and may contribute to chronic adverse remodeling of noninfarcted segments. Single cell studies have revealed a remarkable heterogeneity of macrophage populations in infarcted hearts; however, the relations between transcriptomic profiles and functional properties remain poorly defined. This review manuscript discusses the fate, mechanisms of expansion and activation, and role of macrophages in the infarcted heart. Considering their critical role in injury, repair, and remodeling, macrophages are important, but challenging, targets for therapeutic interventions in myocardial infarction.

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.

Identification and Verification of Feature Biomarkers Associated With Immune Cells in Dilated Cardiomyopathy by Bioinformatics Analysis

Objective: To explore immune-related feature genes in patients with dilated cardiomyopathy (DCM).

Methods: Expression profiles from three datasets (GSE1145, GSE21610 and GSE21819) of human cardiac tissues of DCM and healthy controls were downloaded from the GEO database. After data preprocessing, differentially expressed genes (DEGs) were identified by the ‘limma’ package in R software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were then performed to identify biological functions of the DEGs. The compositional patterns of stromal and immune cells were estimated using xCell. Hub genes and functional modules were identified based on protein-protein interaction (PPI) network analysis by STRING webtool and Cytoscape application. Correlation analysis was performed between immune cell subtypes and hub genes. Hub genes with |correlation coefficient| > 0.5 and p value <0.05 were selected as feature biomarkers. A logistic regression model was constructed based on the selected biomarkers and validated in datasets GSE5406 and GSE57338.

Results: A total of 1,005 DEGs were identified. Functional enrichment analyses indicated that extracellular matrix remodeling and immune and inflammation disorder played important roles in the pathogenesis of DCM. Immune cells, including CD8⁺ T-cells, macrophages M1 and Th1 cells, were proved to be significantly changed in DCM patients by immune cell infiltration analysis. In the PPI network analysis, STAT3, IL6, CCL2, PIK3R1, ESR1, CCL5, IL17A, TLR2, BUB1B and MYC were identified as hub genes, among which CCL2, CCL5 and TLR2 were further screened as feature biomarkers by using hub genes and immune cells correlation analysis. A diagnosis model was successfully constructed by using the three biomarkers with area under the curve (AUC) scores 0.981, 0.867 and 0.946 in merged dataset, GSE5406 and GSE57338, respectively.

Conclusion: The present study identified three immune-related genes as diagnostic biomarkers for DCM, providing a novel perspective of immune and inflammatory response for the exploration of DCM molecular mechanisms.

Inhaled diesel exhaust particles result in microbiome-related systemic inflammation and altered cardiovascular disease biomarkers in C57Bl/6 male mice

BACKGROUND

The gut microbiota plays a vital role in host homeostasis and is associated with inflammation and cardiovascular disease (CVD) risk. Exposure to particulate matter (PM) is a known mediator of inflammation and CVD and is reported to promote dysbiosis and decreased intestinal integrity. However, the role of inhaled traffic-generated PM on the gut microbiome and its corresponding systemic effects are not well-characterized. Thus, we investigated the hypothesis that exposure to inhaled diesel exhaust particles (DEP) alters the gut microbiome and promotes microbial-related inflammation and CVD biomarkers. 4-6-week-old male C57Bl/6 mice on either a low-fat (LF, 10% fat) or high-fat (HF, 45% fat) diet were exposed via oropharyngeal aspiration to 35 μg DEP suspended in 35 μl saline or saline only (CON) 2x/week for 30 days. To determine whether probiotics could prevent diet or DEP exposure mediated alterations in the gut microbiome or systemic outcomes, a subset of animals on the HF diet were treated orally with 0.3 g/day (~ 7.5 × 108 CFU/day) of Winclove Ecologic® Barrier probiotics throughout the study.

RESULTS

Our results show that inhaled DEP exposure alters gut microbial profiles, including reducing Actinobacteria and expanding Verrucomicrobia and Proteobacteria. We observed increased circulating LPS, altered circulating cytokines (IL-1α, IL-3, IL-13, IL-15, G-CSF, LIF, MIP-2, and TNF-α), and CVD biomarkers (siCAM, PAI-1, sP-Selectin, thrombomodulin, and PECAM) in DEP-exposed and/or HF diet mice. Furthermore, probiotics attenuated the observed reduction of Actinobacteria and expansion of Proteobacteria in DEP-exposed and HF-diet mice. Probiotics mitigated circulating cytokines (IL-3, IL-13, G-CSF, RANTES, and TNF- α) and CVD biomarkers (siCAM, PAI-1, sP-Selectin, thrombomodulin, and PECAM) in respect to DEP-exposure and/or HF diet.

CONCLUSION

Key findings of this study are that inhaled DEP exposure alters small intestinal microbial profiles that play a role in systemic inflammation and early CVD biomarkers. Probiotic treatment in this study was fundamental in understanding the role of inhaled DEP on the microbiome and related systemic inflammatory and CVD biomarkers.

Clec4e-Receptor Signaling in Myocardial Repair After Ischemia-Reperfusion Injury

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The role of the CLEC4E during myocardial healing after ischemia-reperfusion injury is unknown.

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CLEC4E deletion is associated with reduced cardiac injury, inflammation, and left ventricular structural and functional remodeling.

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CLEC4E is a promising target to modulate myocardial inflammation and enhance repair after ischemia-reperfusion injury.

The bacterial C-type lectin domain family 4 member E (CLEC4E) has an important role in sterile inflammation, but its role in myocardial repair is unknown. Using complementary approaches in porcine, murine, and human samples, we show that CLEC4E expression levels in the myocardium and in blood correlate with the extent of myocardial injury and left ventricular (LV) functional impairment. CLEC4E expression is markedly increased in the vasculature, cardiac myocytes, and infiltrating leukocytes in the ischemic heart. Loss of Clec4e signaling is associated with reduced acute cardiac injury, neutrophil infiltration, and infarct size. Reduced myocardial injury in Clec4e^–/– translates into significantly improved LV structural and functional remodeling at 4 weeks’ follow-up. The early transcriptome of LV tissue from Clec4e^–/– mice versus wild-type mice reveals significant upregulation of transcripts involved in myocardial metabolism, radical scavenging, angiogenesis, and extracellular matrix organization. Therefore, targeting CLEC4E in the early phase of ischemia-reperfusion injury is a promising therapeutic strategy to modulate myocardial inflammation and enhance repair after ischemia-reperfusion injury.

Full-length transcriptome analysis reveals the mechanism of acupuncture at PC6 improves cardiac function in myocardial ischemia model

Background

The pathological process of myocardial ischemia (MI) is very complicated. Acupuncture at PC6 has been proved to be effective against MI injury, but the mechanism remains unclear. This study investigated the mechanism that underlies the effect of acupuncture on MI through full-length transcriptome.

Methods

Adult male C57/BL6 mice were randomly divided into control, MI, and PC6 groups. Mice in MI and PC6 group generated MI model by ligating the left anterior descending (LAD) coronary artery. The samples were collected 5 days after acupuncture treatment.

Results

The results showed that treatment by acupuncture improved cardiac function, decreased myocardial infraction area, and reduced the levels of cTnT and cTnI. Based on full-length transcriptome sequencing, 5083 differential expression genes (DEGs) and 324 DEGs were identified in the MI group and PC6 group, respectively. These genes regulated by acupuncture were mainly enriched in the inflammatory response pathway. Alternative splicing (AS) is a post-transcriptional action that contributes to the diversity of protein. In all samples, 8237 AS events associated with 1994 genes were found. Some differential AS-involved genes were enriched in the pathway related to heart disease. We also identified 602 new genes, 4 of which may the novel targets of acupuncture in MI.

Conclusions

Our findings suggest that the effect of acupuncture on MI may be based on the multi-level regulation of the transcriptome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00465-8.

Biologics and their delivery systems: Trends in myocardial infarction

Cardiovascular disease is the leading cause of death around the world, in which myocardial infarction (MI) is a precipitating event. However, current therapies do not adequately address the multiple dysregulated systems following MI. Consequently, recent studies have developed novel biologic delivery systems to more effectively address these maladies. This review utilizes a scientometric summary of the recent literature to identify trends among biologic delivery systems designed to treat MI. Emphasis is placed on sustained or targeted release of biologics (e.g. growth factors, nucleic acids, stem cells, chemokines) from common delivery systems (e.g. microparticles, nanocarriers, injectable hydrogels, implantable patches). We also evaluate biologic delivery system trends in the entire regenerative medicine field to identify emerging approaches that may translate to the treatment of MI. Future developments include immune system targeting through soluble factor or chemokine delivery, and the development of advanced delivery systems that facilitate the synergistic delivery of biologics.

Visualization of elastin using cardiac magnetic resonance imaging after myocardial infarction as inflammatory response

The aim of this study was to investigate the merits of magnetic resonance imaging (MRI) using an elastin-binding contrast agent after myocardial infarction in mouse models with deletions of monocyte populations. Permanent ligation of the left anterior descending (LAD) artery was conducted in 10 wild-type mice and 10 each of three knockout models: CX3CR-/-, CCR2-/-, and MCP-1-/-. At 7 days and 30 days after permanent ligation, cardiac MRI was performed with a 7 T-Bruker horizontal scanner for in vivo detection of elastin with an elastin/tropoelastin-specific contrast agent (ESMA). Histology was performed with staining for elastin, collagen I and III, and F4/80. Real-time PCR was conducted to quantify the expression of genes for collagen I and III, F4/80, and tumor necrosis factor alpha (TNFα). Histological and ESMA-indicated elastin areas were strongly correlated (r = 0.8). 30 days after permanent ligation, CCR2-deficient mice demonstrated higher elastin levels in the scar relative to MCP-1-/- (p < 0.04) and wild-type mice (p < 0.02). The ejection fraction was lower in CCR2-deficient mice. In vivo MRI in mouse models of MI can detect elastin deposition after myocardial infarction, highlighting the pivotal role of elastin in myocardial remodeling in mouse models with deletions of monocyte populations.

The Dynamic Interplay Between Cardiac Inflammation and Fibrosis

Heart failure is a leading cause of death worldwide. While there are multiple etiologies contributing to the development of heart failure, all cause result in impairments in cardiac function that is characterized by changes in cardiac remodeling and compliance. Fibrosis is associated with nearly all forms of heart failure and is an important contributor to disease pathogenesis. Inflammation also plays a critical role in the heart and there is a large degree of interconnectedness between the inflammatory and fibrotic response. This review discusses the cellular and molecular mechanisms contributing to inflammation and fibrosis and the interplay between the two.

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.

Pre-culture of mesenchymal stem cells within RGD-modified hyaluronic acid hydrogel improves their resilience to ischaemic conditions

The incorporation of the RGD peptide (arginine-glycine-aspartate) into biomaterials has been proposed to promote cell adhesion to the matrix, which can influence and control cell behaviour and function. While many studies have utilised RGD modified biomaterials for cell delivery, few have examined its effect under the condition of reduced oxygen and nutrients, as found at ischaemic injury sites. Here, we systematically examine the effect of RGD on hMSCs in hyaluronic acid (HA) hydrogel under standard and ischaemic culture conditions, to elucidate under what conditions RGD has beneficial effects over unmodified HA and its effectiveness in improving cell viability. Results demonstrate that under standard culture conditions, RGD significantly increased hMSC spreading and the release of vascular endothelial factor-1 (VEGF) and monocyte chemoattractant factor-1 (MCP-1), compared to unmodified HA hydrogel. As adhesion is known to influence cell survival, we hypothesised that cells in RGD hydrogels would exhibit increased cell viability under ischaemic culture conditions. However, results demonstrate that cell viability and protein release was comparable in both RGD modified and unmodified HA hydrogels. Confocal imaging revealed cellular morphology indicative of weak cell adhesion. Subsequent investigations found that RGD was could exert positive effects on encapsulated cells under ischaemic conditions but only if hMSCs were pre-cultured under standard conditions to allow strong adhesion to RGD before exposure. Together, these results provide novel insight into the value of RGD introduction and suggest that the adhesion of hMSCs to RGD prior to delivery could improve survival and function at ischaemic injury sites. STATEMENT OF SIGNIFICANCE: The development of a biomaterial scaffold capable of maintaining cell viability while promoting cell function is a major research goal in the field of cardiac tissue engineering. This study confirms the suitability of a modified HA hydrogel whereby stem cells in the modified hydrogel showed significantly greater cell spreading and protein secretion compared to cells in the unmodified HA hydrogel. A pre-culture period allowing strong adhesion of the cells to the modified hydrogel was shown to improve cell survival under conditions that mimic the myocardium post-MI. This finding may have a significant impact on the use and timelines of modifications to improve stem cell survival in harsh environments like the injured heart.

Ischemia/Reperfusion Injury: Pathophysiology, Current Clinical Management, and Potential Preventive Approaches

Myocardial ischemia reperfusion syndrome is a complex entity where many inflammatory mediators play different roles, both to enhance myocardial infarction-derived damage and to heal injury. In such a setting, the establishment of an effective therapy to treat this condition has been elusive, perhaps because the experimental treatments have been conceived to block just one of the many pathogenic pathways of the disease, or because they thwart the tissue-repairing phase of the syndrome. Either way, we think that a discussion about the pathophysiology of the disease and the mechanisms of action of some drugs may shed some clarity on the topic.

Effects of left ventricular assist device on heart failure patients: A bioinformatics analysis

With the acceleration of demographic aging, heart failure has become a global public health issue. Left ventricular assist device (LVAD) provides a therapeutic option serving as a bridge to transplantation or destination treatment for end-stage heart failure. However, neither the molecular mechanism nor the gene expression profile of LVAD pathophysiology is well understood. Microarray dataset (GSE21610) was retrieved from the online database of the gene expression omnibus (GEO). Differentially expressed genes (DEGs) between microarrays obtained before and after LVAD therapy were analyzed using GEO2R. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis were carried out, followed by protein-protein interaction (PPI) network construction, which was further visualized by the Cytoscape software. Finally, a target gene-microRNA (miRNA) network was built using the NetworkAnalyst to predict potential miRNA interactions. A total of 36 upregulated DEGs and 14 downregulated DEGs were screened out. Five hub genes with the highest degree of connectivity were identified, including CCL2, CX3CR1, CD163, TLR7, and SERPINE1. CCL2 was identified as the most outstanding hub gene which is specially regulated by miR-124, miR-141, and miR-495. Our study indicates that CCL2 is crucial to the LVAD pathophysiology. The identified hub genes may be involved in cardiac inflammatory responses, remodeling, and the chemokine signaling pathway. These DEGs, pathways, hub genes, miRNAs are valuable for further investigations. This study provides a better understanding of the gene expression profile in LVAD pathophysiology.

Low serum levels of CCL2 are associated with worse prognosis in patients with Acute Coronary Syndrome: 2-year survival analysis

Inflammation is very important in Acute Coronary Syndrome (ACS) as well as in cardiac remodeling after an acute myocardial infarction (MI). Our study examined the prognostic value of Chemokine (C-C motif) ligand 2 (CCL2) in patients with ACS in the ERICO (Strategy of Registry of Acute Coronary Syndrome) study. We evaluated serum samples from 803 patients. The prognostic value of CCL2 was evaluated at the 2-year follow-up, according to cutoff points established by the median. Kaplan-Meier curves and Cox regression were used for analysis of all-cause mortality, cardiovascular mortality, and a combined outcome of fatal myocardial infarction or new non-fatal MI. There were 115 deaths from all causes, 78 deaths due to cardiovascular causes and 67 events in combined outcomes. CCL2 levels below the median (≤100.9 pg/mL) were associated with increased risk of MI death or new non-fatal MI, even after model adjustment. Low serum levels of CCL2 shows a significant association with fatal or new non-fatal MI.

Deficiency of Duffy Antigen Receptor for Chemokines Ameliorated Cochlear Damage From Noise Exposure

Cochlear inflammatory response to various environmental insults, including acoustic and ototoxic overexposures, has been increasingly become a topic of interest. As the immune response is associated with both pathology and protection, targeting specific components of the immune response is expected to dissect the relationships between cellular damage and inflammation-associated protection and repair in the cochlea. Duffy antigen receptor for chemokines (DARC) is a member of a group of atypical chemokine receptors, and essential for chemokine-regulated leukocyte/neutrophil trafficking during inflammation. Previous studies have reported that Darc deficiency alters chemokine bioavailability and leukocyte homeostasis, leading to significant anti-inflammatory effects in tissues following injury. In this study, we have used Darc knockout mice to determine the impact of a deficiency in this gene on cochlear development, as well as function in cochlea subjected to various stresses. We observed that DARC is not required for normal development of cochlear function, as evidenced by typical hearing sensitivity in juvenile Darc-KO mice, as compared to wild type (WT) C57BL/6 mice. However, Darc-KO mice exhibited improved hearing recovery after intense noise exposure when compared to wild-type. The auditory brainstem response (ABR) threshold shift between KO and WT mice was most obvious at 1-week post-noise exposure. At cochlear locations above the frequency range of the energy band of damaging noise, both hair cell survival and ribbon synapse density were improved in Darc deficient animals. In addition, the mRNA levels of some major inflammatory effectors, including Mcp-1 and Gdf15, were altered in Darc-KO mice compared to control mice at 1, 3 and 7 days post-noise exposure. These data collectively suggest that the normal Darc-dependent inflammatory response slows down the process of hearing recovery, and exacerbates cellular damage in the cochlea after noise exposure.

Alcohol-Mediated Organ Damages: Heart and Brain

Alcohol is one of the most commonly abused substances in the United States. Chronic consumption of ethanol has been responsible for numerous chronic diseases and conditions globally. The underlying mechanism of liver injury has been studied in depth, however, far fewer studies have examined other organs especially the heart and the central nervous system (CNS). The authors conducted a narrative review on the relationship of alcohol with heart disease and dementia. With that in mind, a complex relationship between inflammation and cardiovascular disease and dementia has been long proposed but inflammatory biomarkers have gained more attention lately. In this review we examine some of the consequences of the altered cytokine regulation that occurs in alcoholics in organs other than the liver. The article reviews the potential role of inflammatory markers such as TNF-α in predicting dementia and/or cardiovascular disease. It was found that TNF-α could promote and accelerate local inflammation and damage through autocrine/paracrine mechanisms. Unraveling the mechanisms linking chronic alcohol consumption with proinflammatory cytokine production and subsequent inflammatory signaling pathways activation in the heart and CNS, is essential to improve our understanding of the disease and hopefully facilitate the development of new remedies.

Mechanical regulation of cardiac fibroblast profibrotic phenotypes

Cardiac fibroblasts are essential for beneficial myocardial healing but also cause detrimental adverse remodeling following myocardial infarction. The mechanical properties of the infarcted myocardium and border regions display temporal and spatial characteristics that regulate different aspects of the profibrotic cardiac fibroblast phenotypes.

Cardiac fibrosis is a serious condition currently lacking effective treatments. It occurs as a result of cardiac fibroblast (CFB) activation and differentiation into myofibroblasts, characterized by proliferation, extracellular matrix (ECM) production and stiffening, and contraction due to the expression of smooth muscle α-actin. The mechanical properties of myocardium change regionally and over time after myocardial infarction (MI). Although mechanical cues are known to activate CFBs, it is unclear which specific mechanical stimuli regulate which specific phenotypic trait; thus we investigated these relationships using three in vitro models of CFB mechanical activation and found that 1) paracrine signaling from stretched cardiomyocytes induces CFB proliferation under mechanical conditions similar to those of the infarct border region; 2) direct stretch of CFBs mimicking the mechanical environment of the infarct region induces a synthetic phenotype with elevated ECM production; and 3) progressive matrix stiffening, modeling the mechanical effects of infarct scar maturation, causes smooth muscle α-actin fiber formation, up-regulation of collagen I, and down-regulation of collagen III. These findings suggest that myocyte stretch, fibroblast stretch, and matrix stiffening following MI may separately regulate different profibrotic traits of activated CFBs.

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.

β2-Adrenergic receptor-dependent chemokine receptor 2 expression regulates leukocyte recruitment to the heart following acute injury

Following cardiac injury, early immune cell responses are essential for initiating cardiac remodeling and tissue repair. We previously demonstrated the importance of β2-adrenergic receptors (β2ARs) in the regulation of immune cell localization following acute cardiac injury, with deficient leukocyte infiltration into the damaged heart. The purpose of this study was to investigate the mechanism by which immune cell-expressed β2ARs regulate leukocyte recruitment to the heart following acute cardiac injury. Chemokine receptor 2 (CCR2) expression and responsiveness to C-C motif chemokine ligand 2 (CCL2)-mediated migration were abolished in β2AR knockout (KO) bone marrow (BM), both of which were rescued by β2AR reexpression. Chimeric mice lacking immune cell-specific CCR2 expression, as well as wild-type mice administered a CCR2 antagonist, recapitulated the loss of monocyte/macrophage and neutrophil recruitment to the heart following myocardial infarction (MI) observed in mice with immune cell-specific β2AR deletion. Converse to β2AR ablation, β2AR stimulation increased CCR2 expression and migratory responsiveness to CCL2 in BM. Mechanistically, G protein-dependent β2AR signaling was dispensable for these effects, whereas β-arrestin2-biased β2AR signaling was required for the regulation of CCR2 expression. Additionally, activator protein 1 (AP-1) was shown to be essential in mediating CCR2 expression in response to β2AR stimulation in both murine BM and human monocytes. Finally, reconstitution of β2ARKO BM with rescued expression of a β-arrestin-biased β2AR in vivo restored BM CCR2 expression as well as cardiac leukocyte infiltration following MI. These results demonstrate the critical role of β-arrestin2/AP-1-dependent β2AR signaling in the regulation of CCR2 expression and recruitment of leukocytes to the heart following injury.

Kinetic mRNA Profiling in a Rat Model of Left-Ventricular Hypertrophy Reveals Early Expression of Chemokines and Their Receptors

Left-ventricular hypertrophy (LVH), a risk factor for heart failure and death, is characterized by cardiomyocyte hypertrophy, interstitial cell proliferation, and leukocyte infiltration. Chemokines interacting with G protein-coupled chemokine receptors may play a role in LVH development by promoting recruitment of activated leukocytes or modulating left-ventricular remodeling. Using a pressure overload-induced kinetic model of LVH in rats, we examined during 14 days the expression over time of chemokine and chemokine receptor mRNAs in left ventricles from aortic-banded vs sham-operated animals. Two phases were clearly distinguished: an inflammatory phase (D3-D5) with overexpression of inflammatory genes such as il-1ß, tnfa, nlrp3, and the rela subunit of nf-kb, and a hypertrophic phase (D7-D14) where anp overexpression was accompanied by a heart weight/body weight ratio that increased by more than 20% at D14. No cardiac dysfunction was detectable by echocardiography at the latter time point. Of the 36 chemokines and 20 chemokine receptors analyzed by a Taqman Low Density Array panel, we identified at D3 (the early inflammatory phase) overexpression of mRNAs for the monocyte chemotactic proteins CCL2 (12-fold increase), CCL7 (7-fold increase), and CCL12 (3-fold increase), for the macrophage inflammatory proteins CCL3 (4-fold increase), CCL4 (2-fold increase), and CCL9 (2-fold increase), for their receptors CCR2 (4-fold increase), CCR1 (3-fold increase), and CCR5 (3-fold increase), and for CXCL1 (8-fold increase) and CXCL16 (2-fold increase). During the hypertrophic phase mRNA expression of chemokines and receptors returned to the baseline levels observed at D0. Hence, this first exhaustive study of chemokine and chemokine receptor mRNA expression kinetics reports early expression of monocyte/macrophage-related chemokines and their receptors during the development of LVH in rats, followed by regulation of inflammation as LVH progresses.

Cellular recruitment in myocardial ischaemia/reperfusion injury

BACKGROUND

Myocardial infarction (MI) is strictly linked to atherosclerosis. Beyond the mechanical narrowing of coronary vessels lumen, during MI a great burden of inflammation is carried out. One of the crucial events is represented by the ischaemia/reperfusion injury, a complex event involving inflammatory cells (such as neutrophils, platelets, monocytes/macrophages, lymphocytes and mast cells) and key activating signals (such as cytokines, chemokines and growth factors). Cardiac repair following myocardial infarction is dependent on a finely regulated response involving a sequential recruitment and the clearance of different subsets of inflammatory cells.

MATERIALS AND METHODS

This narrative review was based on the works detected on PubMed and MEDLINE up to November 2015.

RESULTS

Infarct healing classically follows three overlapping phases: the inflammatory phase, in which the innate immune pathways are activated and inflammatory leucocytes are recruited in order to clear the wound from dead cells; the proliferative phase, characterized by the suppression of pro-inflammatory signalling and infiltration of 'repairing' cells secreting matrix proteins in the injured area; and the maturation phase, which is associated with the quiescence and the elimination of the reparative cells together with cross-linking of the matrix. All these phases are timely regulated by the production of soluble mediators, such as cytokines, chemokines and growth factors.

CONCLUSION

Targeting inflammatory cell recruitment early during reperfusion and healing might be promising to selectively inhibit injury and favour repair. This approach might substantially improve adverse postischaemic left ventricle remodelling, characterized by dilation, hypertrophy of viable segments and progressive dysfunction.

Cardiac Stem Cell Secretome Protects Cardiomyocytes from Hypoxic Injury Partly via Monocyte Chemotactic Protein-1-Dependent Mechanism

Cardiac stem cells (CSCs) were known to secrete diverse paracrine factors leading to functional improvement and beneficial left ventricular remodeling via activation of the endogenous pro-survival signaling pathway. However, little is known about the paracrine factors secreted by CSCs and their roles in cardiomyocyte survival during hypoxic condition mimicking the post-myocardial infarction environment. We established Sca-1+/CD31- human telomerase reverse transcriptase-immortalized CSCs (Sca-1+/CD31- CSCs(hTERT)), evaluated their stem cell properties, and paracrine potential in cardiomyocyte survival during hypoxia-induced injury. Sca-1+/CD31- CSCs(hTERT) sustained proliferation ability even after long-term culture exceeding 100 population doublings, and represented multi-differentiation potential into cardiomyogenic, endothelial, adipogenic, and osteogenic lineages. Dominant factors secreted from Sca-1+/CD31- CSCs(hTERT) were EGF, TGF-β1, IGF-1, IGF-2, MCP-1, HGF R, and IL-6. Among these, MCP-1 was the most predominant factor in Sca-1+/CD31- CSCs(hTERT) conditioned medium (CM). Sca-1+/CD31- CSCs(hTERT) CM increased survival and reduced apoptosis of HL-1 cardiomyocytes during hypoxic injury. MCP-1 silencing in Sca-1+/CD31- CSCs(hTERT) CM resulted in a significant reduction in cardiomyocyte apoptosis. We demonstrated that Sca-1+/CD31- CSCs(hTERT) exhibited long-term proliferation capacity and multi-differentiation potential. Sca-1+/CD31- CSCs(hTERT) CM protected cardiomyocytes from hypoxic injury partly via MCP-1-dependent mechanism. Thus, they are valuable sources for in vitro and in vivo studies in the cardiovascular field.

Chemokines and Heart Disease: A Network Connecting Cardiovascular Biology to Immune and Autonomic Nervous Systems

Among the chemokines discovered to date, nineteen are presently considered to be relevant in heart disease and are involved in all stages of cardiovascular response to injury. Chemokines are interesting as biomarkers to predict risk of cardiovascular events in apparently healthy people and as possible therapeutic targets. Moreover, they could have a role as mediators of crosstalk between immune and cardiovascular system, since they seem to act as a “working-network” in deep linkage with the autonomic nervous system. In this paper we will describe the single chemokines more involved in heart diseases; then we will present a comprehensive perspective of them as a complex network connecting the cardiovascular system to both the immune and the autonomic nervous systems. Finally, some recent evidences indicating chemokines as a possible new tool to predict cardiovascular risk will be described.

Transcriptomic Analysis of Myocardial Ischemia Using the Blood of Rat

Myocardial ischemia is a pathological state of heart with reduced blood flow to heart and abnormal myocardial energy metabolism. This disease occurs commonly in middle aged and elderly people. Several studies have indicated that the rat was an appropriate animal model used to study myocardial ischemia. In this study, in order to gain insights into the pathogenesis of myocardial ischemia, we sequenced the transcriptomes of three normal rats as control and the same number of myocardial ischemia rats. We sequenced the genomes of 6 rats, including 3 cases (myocardial ischemia) and 3 controls using Illumina HiSeq 2000. Then we calculated the gene expression values and identified differentially expressed genes based on reads per kilobase transcriptome per million (RPKM). Meanwhile we performed a GO enrichment analysis and predicted novel transcripts. In our study, we found that 707 genes were up-regulated and 21 genes were down-regulated in myocardial ischemia rats by at least 2-fold compared with controls. By the distribution of reads and the annotation of reference genes, we found 1,703 and 1,552 novel transcripts in cases and controls, respectively. At the same time, we refined the structure of 9,587 genes in controls and 10,301 in cases. According to the results of GO term and pathway analysis of differentially expressed genes, we found that the immune response, stimulus response, response to stress and some diseases may be associated with myocardial ischemia. Since many diseases, especially immune diseases, are associated with myocardial ischemia, we should pay more attention to the complications which might result from myocardial ischemia.

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.

Chemokine contribution in stem cell engraftment into the infarcted myocardium

Modern life styles have made cardiovascular disease the leading cause of morbidity and mortality worldwide. Although current treatments substantially ameliorate patients’ prognosis after MI, they cannot restore the affected tissue or entirely re-establish organ function. Therefore, the main goal of modern cardiology should be to design strategies to reduce myocardial necrosis and optimize cardiac repair following MI. Cell-based therapy was considered a novel and potentially new strategy in regenerative medicine; however, its clinical implementation has not yielded the expected results. Chemokines seem to increase the efficiency of cell-therapy and may represent a reliable method to be exploited in the future. This review surveys current knowledge of cell therapy and highlights key insights into the role of chemokines in stem cell engraftment in infarcted myocardium and their possible clinical implications.

Carboxyl terminus of heat shock protein 70-interacting protein inhibits angiotensin II-induced cardiac remodeling

BACKGROUND

The carboxyl terminus of heat shock protein 70-interacting protein (CHIP), an E3 ligase/chaperone, was found to protect cardiomyocytes against apoptosis induced by ischemic injury; however, the functional role of CHIP in remodeling induced by angiotensin II (Ang II) remains unclear.

METHODS

We generated CHIP-overexpressed transgenic (TG) mice infused with Ang II (1,500 ng/kg/min) or saline for days or small interfering RNA (siRNA) knockdown of neonatal rat cardiomyocytes. Heart sections were stained with hematoxylin and eosin, Masson trichrome, TdT-mediated dUTP nick-end labeling (TUNEL) staining, and immunohistochemistry, and the levels of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPK) were measured by western blot analysis.

RESULTS

Seven days after Ang II infusion, cardiac-specific overexpression of CHIP significantly enhanced cardiac contractile performance in mice and attenuated cardiac apoptosis, fibrosis, and inflammation: the number of TUNEL-positive cells, fibrotic areas, macrophage infiltration, and the expression of interleukin-1β (IL-1β), IL-6, monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1) in heart tissues were decreased as compared with wild-type (WT) mice (all P < 0.05). In contrast, CHIP siRNA knockdown markedly increased Ang II-induced apoptosis and the expression of proinflammatory cytokines, as compared with siRNA control. The mechanisms underlying these beneficial actions were associated with CHIP-mediated inhibition of NF-κB and MAPK (p38 and JNK) pathways.

CONCLUSIONS

CHIP plays an important role in regulating Ang II-triggered hypertensive cardiac apoptosis, inflammation, and fibrosis.

Effects of interleukin-33 on cardiac fibroblast gene expression and activity

Interleukin-33 (IL-33) is a recently described member of the interleukin-1 (IL-1) family. It is produced by diverse cell types in response to a variety of stresses including hemorrhage and increased mechanical load. Though only relatively recently discovered, IL-33 has been shown to participate in several pathological processes including promoting type 2 T helper cell-associated autoimmune diseases. In contrast, IL-33 has been also found to have protective effects in cardiovascular diseases. Recent studies have illustrated that IL-33 attenuates cardiac fibrosis induced by increased cardiovascular load in mice (transaortic constriction). Since cardiac fibrosis is largely dependent on increased production of extracellular matrix by cardiac fibroblasts, we hypothesized that IL-33 directly inhibits pro-fibrotic activities of these cells. Experiments have been carried out with isolated rat cardiac fibroblasts to evaluate the effects of IL-33 on the modulation of cardiac fibroblast gene expression and function to test this hypothesis. The expression of the IL-33 receptor, interleukin-1 receptor-like 1 (ST2), was detected at the mRNA and protein levels in isolated adult rat cardiac fibroblasts. Subsequently, the effects of IL-33 treatment (0-100 ng/ml) on the expression of extracellular matrix proteins and pro-inflammatory cytokines/chemokines were examined as well as the effects on rat cardiac fibroblast activities including proliferation, collagen gel contraction and migration. While IL-33 did not directly inhibit collagen I and collagen III production, it yielded a dose-dependent increase in the expression of interleukin-6 and monocyte chemotactic protein-1. Treatment of rat cardiac fibroblasts with IL-33 also impaired the migratory activity of these cells. Further experiments illustrated that IL-33 rapidly activated multiple signaling pathways including extracellular signal-regulated kinases, p38 mitogen-activated protein kinase, c-Jun N-terminal kinases and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) in a dose-dependent manner. Experiments were carried out with pharmacological inhibitors to determine the role of specific signaling pathways in the response of fibroblasts to IL-33. These experiments illustrated that the activation of p38 mitogen-activated protein kinase and extracellular signal-regulated kinases are critical to the increased production of interleukin-6 and monocyte chemotactic protein-1 in response to IL-33. These studies suggest that IL-33 has an important role in the modulation of fibroblast function and gene expression. Surprisingly, IL-33 had no effect on the expression of genes encoding extracellular matrix components or on proliferation, markers typical of fibrosis. The major effects of IL-33 detected in these studies included inhibition of cell migration and activation of cytokine/chemokine expression. The previously reported inhibition of cardiac fibrosis may include more complicated mechanisms that involve other cardiac cell types. Future studies aimed at determining the effects of IL-33 on other cardiac cell types are warranted.

Repair after myocardial infarction, between fantasy and reality: the role of chemokines

Despite considerable progress over the last decades, acute myocardial infarction continues to remain the major cause of morbidity and mortality worldwide. The present therapies include only cause-dependent interventions, which are not able to reduce myocardial necrosis and optimize cardiac repair following infarction. This review highlights the cellular and molecular processes after myocardial injury and focuses on chemokines, the main modulators of the inflammatory and reparatory events, as the most valuable drug targets.

Pigment epithelial-derived factor and melanoma differentiation associated gene-7 cytokine gene therapies delivered by adipose-derived stromal/mesenchymal stem cells are effective in reducing prostate cancer cell growth

Adipose-derived stromal/mesenchymal stem cells (ASC) have gained interest as promising tools for delivering cancer therapy. Adipose tissue can be obtained readily in amounts sufficient for ASC isolation, which can be expanded rapidly, allowing its use at low passage numbers, and can be transduced by viral and nonviral means. Our goal was to examine the potential of ASC to deliver cytokine gene therapies melanoma differentiation associated gene-7 (MDA-7) or pigment epithelial-derived factor (PEDF) to cancer cells. These novel cytokines are a potent proapoptotic and an antiangiogenesis mediator, respectively, with potential as antitumor agents. Expression of cytokine therapies did not adversely affect ASC biology, and these cells were still able to differentiate and retain normal viability. The ASC cytokine therapies were efficient in reducing tumor cell growth in coculture and also in suppressing in vitro angiogenesis phenotypes. We also observed that ASC retained their innate ability to migrate toward tumor cells in coculture, and this ability could be blocked by inhibition of CXCR4 signaling. The ASC were found to be nontumorigenic in vitro using a soft agar assay, as well as in vivo, utilizing 2 prostate cancer xenograft models. The ASC-MDA7 only reduced tumor growth in the TRAMP-C2-Ras (TC2Ras) prostate cancer model. The ASC-PEDF, however, reduced growth in both the TC2Ras and the PC3 highly aggressive prostate cancer models, and it was able to completely prevent prostate tumor establishment in vivo. In conclusion, ASC expressing PEDF and MDA7 could effectively reduce prostate tumor growth in vivo, suggesting ASC-cytokine therapies might have translational applications, especially the PEDF modality.

Integrins and monocyte migration to the ischemic myocardium

AIMS

Characterize mononuclear cell migration after acute-myocardial infarction (MI).

MATERIAL AND METHODS

Male Lewis rats underwent a left thoracotomy and ligation of the left anterior descending coronary artery (MI group). Control animals underwent thoracotomy without ligation (Sham group). Animals were sacrificed at 0, 2, 4, or 24 hr after the onset of ischemia. Leukocyte migration was assessed using isolated and In(111) labeled mononuclear cells (injected at the onset of ischemia) and gamma-count determined at 24 hours. Inhibition of migration was evaluated with monoclonal anti alpha4 and/or beta2 antibodies.

RESULTS

Serum troponin was significantly elevated in animals with MI as compared with Sham (p = .017). Labeled mononuclear cell migration was five-fold higher in MI-treated animals than in Sham (p = .006). ED-1 positive mononuclear cells were confirmed in the left myocardium after 24 hr of ischemia. MCP-1 mRNA was significantly elevated in the left myocardium at 2 hr and 4 hr and peaked at 24 hr (p <.05). In addition, alpha4 integrin blockade inhibited labeled mononuclear cell migration by 22%. Blockade of beta2 integrin inhibited mononuclear cell migration by 48%, while the combined alpha4+beta2 blockade resulted in 59% inhibition of labeled mononuclear cell migration compared with treatment with isotype control antibody (p = .001).

CONCLUSIONS

Significant ED1+ mononuclear cell migration within 24 hr of MI correlated with peak MCP-1 mRNA. Monoclonal antibody blockade suggested that early mononuclear cell migration is dependent only in part on alpha4 and beta2 integrins.

Effects of CXCR4 gene transfer on cardiac function after ischemia-reperfusion injury

Acute coronary occlusion is the leading cause of death in the Western world. There is an unmet need for the development of treatments to limit the extent of myocardial infarction (MI) during the acute phase of occlusion. Recently, investigators have focused on the use of a chemokine, CXCL12, the only identified ligand for CXCR4, as a new therapeutic modality to recruit stem cells to individuals suffering from MI. Here, we examined the effects of overexpression of CXCR4 by gene transfer on MI. Adenoviruses carrying the CXCR4 gene were injected into the rat heart one week before ligation of the left anterior descending coronary artery followed by 24 hours reperfusion. Cardiac function was assessed by echocardiography couple with 2,3,5-Triphenyltetrazolium chloride staining to measure MI size. In comparison with control groups, rats receiving Ad-CXCR4 displayed an increase in infarct area (13.5% +/- 4.1%) and decreased fractional shortening (38% +/- 5%). Histological analysis revealed a significant increase in CXCL12 and tumor necrosis factor-alpha expression in ischemic area of CXCR4 overexpressed hearts. CXCR4 overexpression was associated with increased influx of inflammatory cells and enhanced cardiomyocyte apoptosis in the infarcted heart. These data suggest that in our model overexpressing CXCR4 appears to enhance ischemia/reperfusion injury possibly due to enhanced recruitment of inflammatory cells, increased tumor necrosis factor-alpha production, and activation of cell death/apoptotic pathways.

MCP-1 causes cardiomyoblast death via autophagy resulting from ER stress caused by oxidative stress generated by inducing a novel zinc-finger protein, MCPIP

MCP-1 (monocyte chemotactic protein-1) plays a critical role in the development of heart failure that is known to involve apoptosis. How MCP-1 contributes to cell death involved in the development of heart disease is not understood. In the present study we show that MCP-1 causes death in cardiac myoblasts, H9c2 cells, by inducing oxidative stress which causes ER stress leading to autophagy via a novel zinc-finger protein, MCPIP (MCP-1-induced protein). MCPIP expression caused cell death, and knockdown of MCPIP attenuated MCP-1-induced cell death. It caused induction of iNOS (inducible NO synthase), translocation of the NADPH oxidase subunit phox47 from the cytoplasm to the membrane, production of ROS (reactive oxygen species), and induction of ER (endoplasmic reticulum) stress markers HSP40 (heat-shock protein 40), PDI (protein disulfide-isomerase), GRP78 (guanine-nucleotide-releasing protein 78) and IRE1alpha (inositol-requiring enzyme 1alpha). It also caused autophagy, as indicated by beclin-1 induction, cleavage of LC3 (microtubule-associated protein 1 light chain 3) and autophagolysosome formation, and apoptosis, as indicated by caspase 3 activation and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling) assay. Inhibitors of oxidative stress, including CeO2 nanoparticles, inhibited ROS formation, ER stress, autophagy and cell death. Specific inhibitors of ER stress inhibited autophagy and cell death as did knockdown of the ER stress signalling protein IRE1. Knockdown of beclin-1 and autophagy inhibitors prevented cell death. This cell death involved caspase 2 and caspase 12, as specific inhibitors of these caspases prevented MCPIP-induced cell death. Microarray analysis showed that MCPIP expression caused induction of a variety of genes known to be involved in cell death. MCPIP caused activation of JNK (c-Jun N-terminal kinase) and p38 and induction of p53 and PUMA (p53 up-regulated modulator of apoptosis). Taken together, these results suggest that MCPIP induces ROS/RNS (reactive nitrogen species) production that causes ER stress which leads to autophagy and apoptosis through caspase 2/12 and IRE1alpha-JNK/p38-p53-PUMA pathway. These results provide the first molecular insights into the mechanism by which elevated MCP-1 levels associated with chronic inflammation may contribute to the development of heart failure.

Overexpression of CXCR1/CXCR2 on mesenchymal stromal cells may be an effective treatment for acute myocardial infarction

Bone marrow (BM)-derived mesenchymal stromal cells (MSC) participate in myocardial repair following myocardial infarction (MI). However, their reparative capability is limited, partly because of poor homing abilities. MI is associated with an inflammatory reaction. Interleukin-8 (IL-8) appears to have a fundamental role in regulating neutrophil localization in ischemic tissues through binding CXCR1/CXCR2 receptors, which show major expression on neutrophils. We hypothesize that the application of IL-8 will enhance the recruitment of overexpressing CXCR1/CXCR2 MSC to sites of degenerated tissue of myocardium, decreasing the ischemic region and improving cardiac function.

The inflammatory response and cardiac repair after myocardial infarction

One of the most important therapeutic targets of current cardiology practice is to determine optimal strategies for the minimization of myocardial necrosis and optimization of cardiac repair following an acute myocardial infarction. Myocardial necrosis after acute myocardial infarction induces complement activation and free radical generation, triggering a cytokine cascade initiated by tumor necrosis factor-alpha (TNF-α) release. When reperfusion of the infarcted area is initiated, intense inflammation follows. Chemokines, cytokines and the complement system play an important role in recruiting neutrophils in the ischemic and reperfused myocardium. Cytokines promote adhesive interactions between leukocytes and endothelial cells, resulting in transmigration of inflammatory cells into the site of injury. The recruited neutrophils have potent cytotoxic effects through the release of proteolytic enzymes, and they interact with adhesion molecules on cardiomyocytes. In spite of the potential injury, reperfusion enhances cardiac repair; this may be related to the inflammatory response. Monocyte chemoattractant protein (MCP)-1 is upregulated in reperfused myocardium and can induce monocyte recruitment in the infarcted area. Monocyte subsets play a role in phagocytosis of dead cardiomyocytes and in granulation tissue formation. In addition, the transforming growth factor (TGF)-β plays a crucial role in cardiac repair by suppressing inflammation. Resolution of inflammatory infiltration, containment of inflammation and the reparative response affecting the infarcted area are essential for optimal infarct healing. Here, we review the current literature on the inflammatory response and cardiac repair after myocardial infarction.

Association of MCP-1 -2518 A/G single nucleotide polymorphism with the serum level of CRP in Slovak patients with ischemic heart disease, angina pectoris, and hypertension

The aim of our work was to find if MCP-1 -2518 (A/G) single nucleotide polymorphism (SNP) influences somehow the serum concentrations of high-sensitive CRP (hsCRP) both in patients suffering from ischemic heart disease (IHD), myocardial infarction (MI), angina pectoris (AP), and hypertension (HT) and in control group of healthy subjects. Totally, 263 patients with the diagnosis of IHD, out of them 89 with MI, 145 with AP, 205 with HT, and also 67 healthy subjects were included in the study. First, we estimated the serum levels of hsCRP. We found that patients with AP had significantly higher serum level of hsCRP than both control group of healthy subjects (P = .043) and IHD patients without AP (P = .026). The presence of the mutant G allele statistically significantly correlated with the higher serum levels of hsCRP in patients with IHD (P = .016), AP (P = .004), and HT (P = .013). Higher correlations were found in men (AP: P = .019; HT: P = .047). In all cases the highest levels of hsCRP were found both in patients and healthy controls with homozygous GG genotype.

Role of MCP-1 in cardiovascular disease: molecular mechanisms and clinical implications

Many of the major diseases, including cardiovascular disease, are widely recognized as inflammatory diseases. MCP-1 (monocyte chemotactic protein-1) plays a critical role in the development of cardiovascular diseases. MCP-1, by its chemotactic activity, causes diapedesis of monocytes from the lumen to the subendothelial space where they become foam cells, initiating fatty streak formation that leads to atherosclerotic plaque formation. Inflammatory macrophages probably play a role in plaque rupture and the resulting ischaemic episode as well as restenosis after angioplasty. There is strong evidence that MCP-1 plays a major role in myocarditis, ischaemia/reperfusion injury in the heart and in transplant rejection. MCP-1 also plays a role in cardiac repair and manifests protective effects under certain conditions. Such protective effects may be due to the induction of protective ER (endoplasmic reticulum) stress chaperones by MCP-1. Under sustained ER stress caused by chronic exposure to MCP-1, the protection would break down resulting in the development of heart failure. MCP-1 is also involved in ischaemic angiogenesis. The recent advances in our understanding of the molecular mechanisms that might be involved in the roles that MCP-1 plays in cardiovascular disease are reviewed. The gene expression changes induced by the signalling events triggered by MCP-1 binding to its receptor include the induction of a novel zinc-finger protein called MCPIP (MCP-1-induced protein), which plays critical roles in the development of the pathophysiology caused by MCP-1 production. The role of the MCP-1/CCR2 (CC chemokine receptor 2) system in diabetes, which is a major risk factor for cardiovascular diseases, is also reviewed briefly. MCP-1/CCR2- and/or MCPIP-targeted therapeutic approaches to intervene in inflammatory diseases, including cardiovascular diseases, may be feasible.

Chemokines and cardiac fibrosis

Several members of the chemokine family play an important role in reparative fibrosis and are involved in the pathogenesis of remodeling following myocardial infarction. Chemokines may regulate the fibrotic process through recruitment and activation of mononuclear cell subsets and fibroblast progenitors (fibrocytes), by exerting direct effects on resident fibroblasts, and by modulating angiogenesis. Monocyte Chemoattractant Protein (MCP)-1/CCL2 is the best studied chemokine in cardiac fibrosis. Disruption of the MCP-1 axis reduces fibrosis attenuating dilation of the infarcted ventricle. In addition, MCP-1 signaling is activated in response to insults that do not cause cardiomyocyte death, such as brief ischemia or pressure overload and regulates fibrous tissue deposition in experimental models of fibrotic non-infarctive cardiomyopathy. Understanding the role of chemokine-mediated interactions in the development of cardiac fibrosis may identify novel therapeutic targets for treatment of patients with heart failure.

The innate immune response in ischemic acute kidney injury

Kidney ischemia reperfusion injury is a major cause of morbidity in both allograft and native kidneys. Ischemia reperfusion-induced acute kidney injury is characterized by early, alloantigen-independent inflammation. Major components of the innate immune system are activated and participate in the pathogenesis of acute kidney injury, plus prime the allograft kidney for rejection. Soluble members of innate immunity implicated in acute kidney injury include the complement system, cytokines, and chemokines. Toll-like receptors (TLRs) are also important contributors. Effector cells that participate in acute kidney injury include the classic innate immune cells, neutrophils and macrophages. Recent data has unexpectedly identified lymphocytes as participants of early acute kidney injury responses. In this review, we will focus on immune mediators that participate in the pathogenesis of ischemic acute kidney injury.

The role of chemokines in transplant graft arterial disease

Despite the development of effective immunosuppressive therapy, transplant graft arterial disease (GAD) remains the major limitation to long-term graft survival. Multiple immune and nonimmune risk factors contribute to this vasculopathic intimal hyperplastic process. Thus, initial interplay between host inflammatory cells and donor endothelial cells triggers alloimmune responses, whereas alloantigen-independent factors such as prolonged ischemia, surgical manipulation, ischemia-reperfusion injury, and hyperlipidemia enhance the antigen-dependent events. Intrinsic to all stages of this process are chemokines, a family of 8- to 10-kDa proteins mediating directional migration of immune cells to sites of inflammation and injury. Beyond their role in immune-cell chemotaxis, chemokines also contribute to cellular activation, vascular remodeling, and angiogenesis. Expression of chemokines and their cognate receptors in allografts correlates with acute organ rejection, as well as GAD. Moreover, chemokine or chemokine receptor blockade prolongs graft survival and attenuates GAD in experimental models. Further studies will likely confirm a substantial utility for antichemokine therapy in human organ transplantation.