Hsp60 and heme oxygenase-1 (Hsp32) in acute myocardial infarction

Emerging role of heat shock proteins in cardiovascular diseases

Heat Shock Proteins (HSPs) are evolutionarily conserved proteins from prokaryotes to eukaryotes. They are ubiquitous proteins involved in key physiological and cellular pathways (viz. inflammation, immunity and apoptosis). Indeed, the survivability of the cells under various stressful conditions depends on appropriate levels of HSP expression. There is a growing line of evidence for the role of HSPs in regulating cardiovascular diseases (CVDs) (viz. hypertension, atherosclerosis, atrial fibrillation, cardiomyopathy and heart failure). Furthermore, studies indicate that a higher concentration of circulatory HSP antibodies correlate to CVDs; some are even potential markers for CVDs. The multifaceted roles of HSPs in regulating cellular signaling necessitate unraveling their links to pathophysiology of CVDs. This review aims to consolidate our understanding of transcriptional (via multiple transcription factors including HSF-1, NF-κB, CREB and STAT3) and post-transcriptional (via microRNAs including miR-1, miR-21 and miR-24) regulation of HSPs. The cytoprotective nature of HSPs catapults them to the limelight as modulators of cell survival. Yet another attractive prospect is the development of new therapeutic strategies against cardiovascular diseases (from hypertension to heart failure) by targeting the regulation of HSPs. Moreover, this review provides insights into how genetic variation of HSPs can contribute to the manifestation of CVDs. It would also offer a bird's eye view of the evolving role of different HSPs in the modulation and manifestation of cardiovascular disease.

Signaling pathways and targeted therapy for myocardial infarction

Although the treatment of myocardial infarction (MI) has improved considerably, it is still a worldwide disease with high morbidity and high mortality. Whilst there is still a long way to go for discovering ideal treatments, therapeutic strategies committed to cardioprotection and cardiac repair following cardiac ischemia are emerging. Evidence of pathological characteristics in MI illustrates cell signaling pathways that participate in the survival, proliferation, apoptosis, autophagy of cardiomyocytes, endothelial cells, fibroblasts, monocytes, and stem cells. These signaling pathways include the key players in inflammation response, e.g., NLRP3/caspase-1 and TLR4/MyD88/NF-κB; the crucial mediators in oxidative stress and apoptosis, for instance, Notch, Hippo/YAP, RhoA/ROCK, Nrf2/HO-1, and Sonic hedgehog; the controller of myocardial fibrosis such as TGF-β/SMADs and Wnt/β-catenin; and the main regulator of angiogenesis, PI3K/Akt, MAPK, JAK/STAT, Sonic hedgehog, etc. Since signaling pathways play an important role in administering the process of MI, aiming at targeting these aberrant signaling pathways and improving the pathological manifestations in MI is indispensable and promising. Hence, drug therapy, gene therapy, protein therapy, cell therapy, and exosome therapy have been emerging and are known as novel therapies. In this review, we summarize the therapeutic strategies for MI by regulating these associated pathways, which contribute to inhibiting cardiomyocytes death, attenuating inflammation, enhancing angiogenesis, etc. so as to repair and re-functionalize damaged hearts.

Forensic significance of intracardiac heme oxygenase-1 expression in acute myocardial ischemia

Heme oxygenase-1 (HO-1), an inducible stress-response protein, exerts anti-oxidant and anti-apoptotic effects. However, its significance in forensic diagnosis of acute ischemic heart diseases (AIHD) such as myocardial infarction (MI) is still unknown. We examined the immunohistochemical expression of HO-1 in the heart samples to discuss their forensic significance to determine acute cardiac ischemia. The heart samples were obtained from 23 AIHD cases and 33 non-AIHD cases as controls. HO-1 positive signals in cardiomyocyte nuclear were detected in 78.2% of AIHD cases, however, that were detected in only 24.2% control cases with statistical difference between AIHD and non-AIHD groups. In contrast to HO-1 protein expression, there was no significant difference in the appearance of myoglobin pallor regions and leukocyte infiltration in the hearts between AIHD and non-AIHD groups. From the viewpoints of forensic pathology, intracardiac HO-1 expression would be considered a valuable marker to diagnose AIHD as the cause of death.

The non-canonical effects of heme oxygenase-1, a classical fighter against oxidative stress

The role of heme oxygenase-1 in resisting oxidative stress and cell protection has always been a hot research topic. With the continuous deepening of research, in addition to directly regulating redox by catalyzing the degradation of heme, HO-1 protein also participates in the gene expression level in a great diversity of methods, thereby initiating cell defense. Particularly the non-canonical nuclear-localized HO-1 and HO-1 protein interactions play the role of a warrior against oxidative stress. Besides, HO-1 may be a promising marker for disease prediction and detection in many clinical trials. Especially for malignant diseases, there may be new advances in the treatment of HO-1 by regulating abnormal ROS and metabolic signaling. The purpose of this review is to systematically sort out and describe several aspects of research to facilitate further detailed mechanism research and clinical application promotion in the future.

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The different subcellular localizations ofHO-1 implies that it has special functions.

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Nuclear HO-1 plays an indispensable role in gene regulation and other aspects.

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The interactions between HO-1 and others provide the possibility to participate in vital physiological processes.

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HO-1 may become a potential disease assessment marker.

Electronic and Tobacco Cigarettes Alter Polyunsaturated Fatty Acids and Oxidative Biomarkers

[Figure: see text].

Clinical Significance of Heme Oxygenase 1 in Tumor Progression

Heme oxygenase 1 (HO-1) plays a key role in cell adaptation to stressors through the antioxidant, antiapoptotic, and anti-inflammatory properties of its metabolic products. For these reasons, in cancer cells, HO-1 can favor aggressiveness and resistance to therapies, leading to poor prognosis/outcome. Genetic polymorphisms of HO-1 promoter have been associated with an increased risk of cancer progression and a high degree of therapy failure. Moreover, evidence from cancer biopsies highlights the possible correlation between HO-1 expression, pathological features, and clinical outcome. Indeed, high levels of HO-1 in tumor specimens often correlate with reduced survival rates. Furthermore, HO-1 modulation has been proposed in order to improve the efficacy of antitumor therapies. However, contrasting evidence on the role of HO-1 in tumor biology has been reported. This review focuses on the role of HO-1 as a promising biomarker of cancer progression; understanding the correlation between HO-1 and clinical data might guide the therapeutic choice and improve the outcome of patients in terms of prognosis and life quality.

Role of mitochondrial quality surveillance in myocardial infarction: From bench to bedside

Myocardial infarction (MI) is the irreversible death of cardiomyocyte secondary to prolonged lack of oxygen or fresh blood supply. Historically considered as merely cardiomyocyte powerhouse that manufactures ATP and other metabolites, mitochondrion is recently being identified as a signal regulator that is implicated in the crosstalk and signal integration of cardiomyocyte contraction, metabolism, inflammation, and death. Mitochondria quality surveillance is an integrated network system modifying mitochondrial structure and function through the coordination of various processes including mitochondrial fission, fusion, biogenesis, bioenergetics, proteostasis, and degradation via mitophagy. Mitochondrial fission favors the elimination of depolarized mitochondria through mitophagy, whereas mitochondrial fusion preserves the mitochondrial network upon stress through integration of two or more small mitochondria into an interconnected phenotype. Mitochondrial biogenesis represents a regenerative program to replace old and damaged mitochondria with new and healthy ones. Mitochondrial bioenergetics is regulated by a metabolic switch between glucose and fatty acid usage, depending on oxygen availability. To maintain the diversity and function of mitochondrial proteins, a specialized protein quality control machinery regulates protein dynamics and function through the activity of chaperones and proteases, and induction of the mitochondrial unfolded protein response. In this review, we provide an overview of the molecular mechanisms governing mitochondrial quality surveillance and highlight the most recent preclinical and clinical therapeutic approaches to restore mitochondrial fitness during both MI and post-MI heart failure.

The expression of myeloperoxidase in thrombi is associated with reduced heme oxygenase-1 induction and worse left ventricular remodeling in patients with acute ST-elevation myocardial infarction

Background

Myeloperoxidase (MPO) secreted by neutrophils is the enzyme that kills bacteria and other pathogens. Acute myocardial infarction (AMI) is usually caused by thrombosis in response to vulnerable plaque rupture. Circulating MPO was found to be associated with increased mortality in AMI patients. However, the relationship between MPO in thrombi and the prognosis of AMI patients remains unknown.

Hypothesis

MPO expression in thrombi is associated with the prognosis of patients who underwent primary percutaneous coronary intervention (PCI) after AMI.

Methods

This study included 41 consecutive patients with acute ST‐elevation myocardial infarction, who successfully underwent primary PCI, during which we collected thrombi remaining in the culprit artery using aspiration catheters. These thrombus samples were fixed, and immunohistochemical staining against MPO and heme oxygenase‐1 (HO‐1) was conducted. Enrolled patients were divided into two groups based on the induction of thrombotic MPO, which was quantified using Image J software.

Methods

We observed that increased MPO was associated with lower left ventricular ejection fraction (LVEF) and worse LV remodeling in AMI patients. Instead, patients with decreased thrombotic MPO induction had a considerable improvement in LVEF 1 month after discharge (54.4 ± 2.0% vs. 61.1 ± 2.3%, p < 0.01). In the MPO group, a reduction in the thrombotic HO‐1 level contributed to the development of adverse LV remodeling. Logistic regression showed that MPO was a considerable risk factor for adverse LV remodeling (adjusted OR 3.70, p < 0.05).

Conclusion

MPO expression in thrombi is associated with reduced LVEF and deteriorated LV remodeling in AMI patients, which may be due to HO‐1 suppression in thrombi.

Heat shock protein 60 and cardiovascular diseases: An intricate love-hate story

Cardiovascular diseases (CVDs) are the result of complex pathophysiological processes in the tissues comprising the heart and blood vessels. Inflammation is the main culprit for the development of cardiovascular dysfunction, and it may be traced to cellular stress events including apoptosis, oxidative and shear stress, and cellular and humoral immune responses, all of which impair the system's structure and function. An intracellular chaperone, heat shock protein 60 (HSP60) is an intriguing example of a protein that may both be an ally and a foe for cardiovascular homeostasis; on one hand providing protection against cellular injury, and on the other triggering damaging responses through innate and adaptive immunity. In this review we will discuss the functions of HSP60 and its effects on cells and the immune system regulation, only to later address its implications in the development and progression of CVD. Lastly, we summarize the outcome of various studies targeting HSP60 as a potential therapeutic strategy for cardiovascular and other diseases.

Blocking Extracellular Chaperones to Improve Cardiac Regeneration

Chronic or acute insults to the myocardium are responsible for the onset of cardiomyopathy and heart failure. Due to the poor regenerative ability of the human adult heart, the survival of cardiomyocytes is a prerequisite to support heart function. Chaperone proteins, by regulating sarcomeric protein folding, function, and turnover in the challenging environment of the beating heart, play a fundamental role in myocardial physiology. Nevertheless, a number of evidences indicate that, under stress conditions or during cell damage, myocardial cells release chaperone proteins that, from the extracellular milieu, play a detrimental function, by perpetuating inflammation and inducing cardiomyocyte apoptosis. Blocking the activity of extracellular chaperones has been proven to have beneficial effects on heart function in preclinical models of myocardial infarction and cardiomyopathy. The application of this approach in combination with tissue engineering strategies may represent a future innovation in cardiac regenerative medicine.

Heat Shock Protein 60 in Cardiovascular Physiology and Diseases

Heat shock protein 60 (HSP60) is a highly conserved protein abundantly expressed in both prokaryotic and eukaryotic cells. In mammals, HSP60 has been primarily considered to reside in the mitochondria, where HSP60 and HSP10 form a complex and facilitate mitochondrial protein folding. However, HSP60 is also observed in the cytoplasm, the plasma membrane, and the extracellular space. HSP60 regulates a broad spectrum of cellular events including protein trafficking, peptide hormone signaling, cell survival, cell proliferation, inflammation, and immunization. In the cardiovascular system, growing evidence indicates that HSP60 could not only play an important role under physiological conditions, but also regulate the initiation and progression of heart failure and atherosclerosis. In this review, we focus on recent progress in understanding the function of HSP60 in cardiomyocytes, endothelial cells, and vascular smooth muscle cells (VSMCs), respectively, and discuss the related signaling pathways that have been found in these cells, so as to illustrate the role of HSP60 in the development of cardiovascular disease.

Oxidative Stress in Peripheral Arterial Disease (PAD) Mechanism and Biomarkers

Hemodynamic dysfunction mainly characterizes pathophysiology of peripheral arterial disease (PAD) leading to chronic ischemia. Hemodynamic dysfunction is the origin of intermittent claudication (chronic PAD) or of critical limb ischemia (very severe PAD). Notably, it is well known that oxidative stress (OxS) plays a pathophysiological role in PAD. The higher production of reactive oxygen species (ROS) from OxS and reduced redox capability are two crucial players in initiating and progressing PAD. A number of biomarkers highlight OxS and monitor it in PAD. The present review summarizes data on OxS, on biomarkers available to mark OxS occurrence and to monitor on PAD progression, as well as to evaluate the effects treatments in PAD patients. In conclusion, by detailing OxS and its biomarkers, we hope to encourage more studies to focus on drugs which combat OxS and inflammation.

Identification of Differentially Expressed Genes and Signaling Pathways in Acute Myocardial Infarction Based on Integrated Bioinformatics Analysis

Background

Acute myocardial infarction (AMI) is a common disease with high morbidity and mortality around the world. The aim of this research was to determine the differentially expressed genes (DEGs), which may serve as potential therapeutic targets or new biomarkers in AMI.

Methods

From the Gene Expression Omnibus (GEO) database, three gene expression profiles (GSE775, GSE19322, and GSE97494) were downloaded. To identify the DEGs, integrated bioinformatics analysis and robust rank aggregation (RRA) method were applied. These DEGs were performed through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses by using Clusterprofiler package. In order to explore the correlation between these DEGs, the interaction network of protein-protein internet (PPI) was constructed using the STRING database. Utilizing the MCODE plug-in of Cytoscape, the module analysis was performed. Utilizing the cytoHubba plug-in, the hub genes were screened out.

Results

57 DEGs in total were identified, including 2 down- and 55 upregulated genes. These DEGs were mainly enriched in cytokine-cytokine receptor interaction, chemokine signaling pathway, TNF signaling pathway, and so on. The module analysis filtered out 18 key genes, including Cxcl5, Arg1, Cxcl1, Spp1, Selp, Ptx3, Tnfaip6, Mmp8, Serpine1, Ptgs2, Il6, Il1r2, Il1b, Ccl3, Ccr1, Hmox1, Cxcl2, and Ccl2. Ccr1 was the most fundamental gene in PPI network. 4 hub genes in total were identified, including Cxcl1, Cxcl2, Cxcl5, and Mmp8.

Conclusion

This study may provide credible molecular biomarkers in terms of screening, diagnosis, and prognosis for AMI. Meanwhile, it also serves as a basis for exploring new therapeutic target for AMI.

The Protective Role of Heme Oxygenase-1 in Atherosclerotic Diseases

Heme oxygenase-1 (HO-1) is an intracellular enzyme that catalyzes the oxidation of heme to generate ferrous iron, carbon monoxide (CO), and biliverdin, which is subsequently converted to bilirubin. These products have anti-inflammatory, anti-oxidant, anti-apoptotic, and anti-thrombotic properties. Although HO-1 is expressed at low levels in most tissues under basal conditions, it is highly inducible in response to various pathophysiological stresses/stimuli. HO-1 induction is thus thought to be an adaptive defense system that functions to protect cells and tissues against injury in many disease settings. In atherosclerosis, HO-1 may play a protective role against the progression of atherosclerosis, mainly due to the degradation of pro-oxidant heme, the generation of anti-oxidants biliverdin and bilirubin and the production of vasodilator CO. In animal models, a lack of HO-1 was shown to accelerate atherosclerosis, whereas HO-1 induction reduced atherosclerosis. It was also reported that HO-1 induction improved the cardiac function and postinfarction survival in animal models of heart failure or myocardial infarction. Recently, we and others examined blood HO-1 levels in patients with atherosclerotic diseases, e.g., coronary artery disease (CAD) and peripheral artery disease (PAD). Taken together, these findings to date support the notion that HO-1 plays a protective role against the progression of atherosclerotic diseases. This review summarizes the roles of HO-1 in atherosclerosis and focuses on the clinical studies that examined the relationships between HO-1 levels and atherosclerotic diseases.

Antioxidative and Cardioprotective Effects of Schisandra chinensis Bee Pollen Extract on Isoprenaline-Induced Myocardial Infarction in Rats

Oxidative stress plays an important role in the pathogenesis of myocardial infarction (MI). Schisandra chinensis bee pollen extract (SCBPE) possesses powerful antioxidant capacity. This study aimed to further explore the antioxidative and cardioprotective effects of SCBPE on acute MI induced by isoprenaline (ISO) in rats. The rats were intragastrically administrated with SCBPE (600, 1200, or 1800 mg/kg/day) and Compound Danshen dropping pills (270 mg/kg/day) for 30 days, then subcutaneously injected with ISO (65 mg/kg/day) on the 29th and 30th day. Compared with the model group, pretreatment with middle and high doses of SCBPE significantly reduced serum aspartate transaminase, lactate dehydrogenase, and creatine kinase activities and increased myocardial superoxide dismutase, glutathione peroxidase, and catalase activities. The histopathologic aspects showed that pathological heart change was found in the model group and reduced to varying degrees in the SCBPE groups. Moreover, the protein expression of nuclear factor-erythroid 2-related factor 2 (Nrf-2), heme oxygenase-1 (HO-1), and Bcl2 in the heart increased in the SCBPE groups, while that of Bax decreased compared to the model group. Besides this, uridine was isolated from S. chinensis bee pollen for the first time. This study could provide a scientific basis for using Schisandra chinensis bee pollen as a functional food for the prevention of MI.

Identification of Candidate Genes and MicroRNAs for Acute Myocardial Infarction by Weighted Gene Coexpression Network Analysis

Background

Identification of potential molecular targets of acute myocardial infarction is crucial to our comprehensive understanding of the disease mechanism. However, studies of gene coexpression analysis via jointing multiple microarray data of acute myocardial infarction still remain restricted.

Methods

Microarray data of acute myocardial infarction (GSE48060, GSE66360, GSE97320, and GSE19339) were downloaded from Gene Expression Omnibus database. Three data sets without heterogeneity (GSE48060, GSE66360, and GSE97320) were subjected to differential expression analysis using MetaDE package. Differentially expressed genes having upper 25% variation across samples were imported in weighted gene coexpression network analysis. Functional and pathway enrichment analyses were conducted for genes in the most significant module using DAVID. The predicted microRNAs to regulate target genes in the most significant module were identified using TargetScan. Moreover, subpathway analyses using iSubpathwayMiner package and GenCLiP 2.0 were performed on hub genes with high connective weight in the most significant module.

Results

A total of 1027 differentially expressed genes and 33 specific modules were screened out between acute myocardial infarction patients and control samples. Ficolin (collagen/fibrinogen domain containing) 1 (FCN1), CD14 molecule (CD14), S100 calcium binding protein A9 (S100A9), and mitochondrial aldehyde dehydrogenase 2 (ALDH2) were identified as critical target molecules; hsa-let-7d, hsa-let-7b, hsa-miR-124-3, and hsa-miR-9-1 were identified as potential regulators of the expression of the key genes in the two biggest modules.

Conclusions

FCN1, CD14, S100A9, ALDH2, hsa-let-7d, hsa-let-7b, hsa-miR-124-3, and hsa-miR-9-1 were identified as potential candidate regulators in acute myocardial infarction. These findings might provide new comprehension into the underlying molecular mechanism of disease.

Plasma Heme Oxygenase-1 Levels in Patients with Coronary and Peripheral Artery Diseases

Aims

Heme oxygenase-1 (HO-1) is an intracellular enzyme that catalyzes the oxidation of heme to generate CO, biliverdin, and iron. Since these products have antiatherogenic properties, HO-1 may play a protective role against the progression of atherosclerosis. However, plasma HO-1 levels in patients with atherosclerotic diseases, such as coronary artery disease (CAD) and peripheral artery disease (PAD), have not been clarified yet.

Methods

We investigated plasma HO-1 levels by ELISA in 410 consecutive patients undergoing elective coronary angiography who also had an ankle-brachial index (ABI) test for PAD screening.

Results

Of the 410 study patients, CAD was present in 225 patients (55%) (1-vessel (1-VD), n = 91; 2-vessel (2-VD), n = 66; 3-vessel disease (3-VD), n = 68). PAD (ABI < 0.9) was found in 36 (9%) patients. Plasma HO-1 levels did not differ between 225 patients with CAD and 185 without CAD (median 0.44 versus 0.35 ng/mL), but they were significantly lower in 36 patients with PAD than in 374 without PAD (0.27 versus 0.41 ng/mL, P < 0.02). After excluding the 36 patients with PAD, HO-1 levels were significantly higher in 192 patients with CAD than in 182 without CAD (0.45 versus 0.35 ng/mL, P < 0.05). HO-1 levels in 4 groups of CAD(−), 1-VD, 2-VD, and 3-VD were 0.35, 0.49, 0.44, and 0.44 ng/mL, respectively, and were highest in 1-VD (P < 0.05). In the multivariate analysis, HO-1 levels were inversely associated with PAD, whereas they were also associated with CAD. The odds ratios for PAD and CAD were 2.12 (95% CI = 1.03–4.37) and 0.65 (95% CI = 0.42–0.99) for the HO-1 level of <0.35 ng/mL, respectively.

Conclusions

Plasma HO-1 levels were found to be low in patients with PAD, in contrast to high levels in patients with CAD.

The non-canonical functions of the heme oxygenases

Heme oxygenase (HO) isoforms catalyze the conversion of heme to carbon monoxide (CO) and biliverdin with a concurrent release of iron, which can drive the synthesis of ferritin for iron sequestration. Most of the studies so far were directed at evaluating the protective effect of these enzymes because of their ability to generate antioxidant and antiapoptotic molecules such as CO and bilirubin. Recent evidences are suggesting that HO may possess other important physiological functions, which are not related to its enzymatic activity and for which we would like to introduce for the first time the term “non canonical functions”. Recent evidence suggest that both HO isoforms may form protein-protein interactions (i.e. cytochrome P450, adiponectin, CD91) thus serving as chaperone-like protein. In addition, truncated HO-1 isoform was localized in the nuclear compartment under certain experimental conditions (i.e. excitotoxicity, hypoxia) regulating the activity of important nuclear transcription factors (i.e. Nrf2) and DNA repair. In the present review, we discuss three potential signaling mechanisms that we refer to as the non-canonical functions of the HO isoforms: protein-protein interaction, intracellular compartmentalization, and extracellular secretion. The aim of the present review is to describe each of this mechanism and all the aspects warranting additional studies in order to unravel all the functions of the HO system.

Redox Aspects of Chaperones in Cardiac Function

Molecular chaperones are stress proteins that allow the correct folding or unfolding as well as the assembly or disassembly of macromolecular cellular components. Changes in expression and post-translational modifications of chaperones have been linked to a number of age- and stress-related diseases including cancer, neurodegeneration, and cardiovascular diseases. Redox sensible post-translational modifications, such as S-nitrosylation, glutathionylation and phosphorylation of chaperone proteins have been reported. Redox-dependent regulation of chaperones is likely to be a phenomenon involved in metabolic processes and may represent an adaptive response to several stress conditions, especially within mitochondria, where it impacts cellular bioenergetics. These post-translational modifications might underlie the mechanisms leading to cardioprotection by conditioning maneuvers as well as to ischemia/reperfusion injury. In this review, we discuss this topic and focus on two important aspects of redox-regulated chaperones, namely redox regulation of mitochondrial chaperone function and cardiac protection against ischemia/reperfusion injury.

Heme oxygenase-1 nuclear translocation regulates bortezomibinduced cytotoxicity and mediates genomic instability in myeloma cells

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by an accumulation of clonal plasma cells in the bone marrow leading to bone destruction and bone marrow failure. Several molecular mechanisms underlie chemoresistance among which heme oxygenase-1 (HO-1) could play a major role. The aim of the present research was to evaluate the impact of HO-1 in MM following bortezomib (BTZ) treatment and how HO-1 is implicated in the mechanisms of chemoresistance. MM cells were treated for 24h with BTZ (15 nM), a boronic acid dipeptide inhibitor of the 26S proteasome used in the treatment of patients with MM as first-line therapy. We evaluated cell viability, reactive oxygen species (ROS) formation, endoplasmic reticulum (ER) stress, HO-1 expression and compartmentalization and cellular genetic instability. Results showed that BTZ significantly reduced cell viability in different MM cell lines and induced ER-stress and ROS formation. Concomitantly, we observed a significant overexpression of both HO-1 gene and protein levels. This effect was abolished by concomitant treatment with 4-phenybutirric acid, a molecular chaperone, which is known to reduce ER-stress. Surprisingly, inhibition of HO activity with SnMP (10μM) failed to increase BTZ sensitivity in MM cells whereas inhibition of HO-1 nuclear translocation by E64d, a cysteine protease inhibitor, increased sensitivity to BTZ and decreased genetic instability as measured by cytokinesis-block micronucleus assay. In conclusion, our data suggest that BTZ sensitivity depends on HO-1 nuclear compartmentalization and not on its enzymatic activity and this finding may represent an important tool to overcome BTZ chemoresistance in MM patients.

Differential expression of myocardial heat shock proteins in rats acutely exposed to fluoride

Acute fluoride (F-) toxicity is known to cause severe cardiac complications and leads to sudden heart failure. Previously, we reported that increased myocardial oxidative damage, apoptosis, altered cytoskeleton and AMPK signaling proteins associated with energy deprivation in acute F- induced cardiac dysfunction. The present study was aimed to decipher the status of myocardial heat shock proteins (Hsps-Hsp27, Hsp32, Hsp40, Hsp60, Hsp70, Hsp90) and heat shock transcription factor 1 (Hsf1) in acute F--intoxicated rats. In order to study the expression of myocardial Hsps, male Wistar rats were treated with single oral doses of 45 and 90 mg/kg F- for 24 h. The expression levels of myocardial Hsps were determined using RT-PCR, western blotting, and immunohistochemical studies. Acute F--intoxicated rats showed elevated levels of both the transcripts and protein expression of Hsf1, Hsp27, Hsp32, Hsp60, and Hsp70 when compared to control. In addition, the expression levels of Hsp40 and Hsp90 were significantly declined in a dose-dependent fashion in F--treated animals. Our result suggests that differential expression of Hsps in the rat myocardium could serve as a balance between pro-survival and death signal during acute F--induced heart failure.

The Heme Oxygenase System in Hematological Malignancies

SIGNIFICANCE

Several lines of evidence suggest that hematological malignancies exhibit an altered redox balance homeostasis that can lead to the activation of various survival pathways that, in turn, lead to the progression of disease and chemoresistance. Among these pathways, the heme oxygenase-1 (HO-1) pathway is likely to play a major role. HO catalyzes the enzymatic degradation of heme with the simultaneous release of carbon monoxide (CO), ferrous iron (Fe²⁺), and biliverdin. This review focuses on the role of HO-1 in various hematological malignancies and the possibility of exploiting such targets to improve the outcome of well-established chemotherapeutic regimens. Recent Advances and Critical Issues: Interestingly, the inhibition of the expression of HO-1 (e.g., with siRNA) or HO activity (with competitive inhibitors) contributes to the increased efficacy of chemotherapy and improves the outcome in animal models. Furthermore, some hematological malignancies (e.g., chronic myeloid leukemia and multiple myeloma) have served to explore the non-canonical functions of HO-1, such as the association between nuclear compartmentalization and genetic instability and/or chemoresistance.

FUTURE DIRECTIONS

The HO system may serve as an important tool in the field of hematological malignancies because it can be exploited to counteract chemoresistance and to monitor the outcome of bone marrow transplants and may be an additional target for combined therapies. Antioxid. Redox Signal. 27, 363-377.

Diabetic human adipose tissue-derived mesenchymal stem cells fail to differentiate in functional adipocytes

Adipose tissue dysfunction represents a hallmark of diabetic patients and is a consequence of the altered homeostasis of this tissue. Mesenchymal stem cells (MSCs) and their differentiation into adipocytes contribute significantly in maintaining the mass and function of adult adipose tissue. The aim of this study was to evaluate the differentiation of MSCs from patients suffering type 2 diabetes (dASC) and how such process results in hyperplasia or rather a stop of adipocyte turnover resulting in hypertrophy of mature adipocytes. Our results showed that gene profile of all adipogenic markers is not expressed in diabetic cells after differentiation indicating that diabetic cells fail to differentiate into adipocytes. Interestingly, delta like 1, peroxisome proliferator-activated receptor alpha, and interleukin 1β were upregulated whereas Sirtuin 1 and insulin receptor substrate 1 gene expression were found downregulated in dASC compared to cells obtained from healthy subjects. Taken together our data indicate that dASC lose their ability to differentiate into mature and functional adipocytes. In conclusion, our in vitro study is the first to suggest that diabetic patients might develop obesity through a hypertrophy of existing mature adipocytes due to failure turnover of adipose tissue. Impact statement In the present manuscript, we evaluated the differentiative potential of mesenchymal stem cells (MSCs) in adipocytes obtained from healthy and diabetic patients. This finding could be of great potential interest for the field of obesity in order to exploit such results to further understand the pathophysiological processes underlying metabolic syndrome. In particular, inflammation in diabetic patients causes a dysfunction in MSCs differentiation and a decrease in adipocytes turnover leading to insulin resistance.

The effect of bergamot on dyslipidemia

BACKGROUND

Statins are the most common used lipid lowering drugs but they may cause adverse effects and despite their well-established therapeutic benefits residual cardiovascular (CV) risk remains. The use of other lipid lowering drugs and nutraceuticals alone or as add-on lipid-modifying therapy can be an option in such cases. Several studies have reported health-related properties of the Citrus fruits, among which bergamot (Citrus bergamia Risso) differs from others by particularly high content of certain compounds.

PURPOSE

This narrative review summarizes the current evidence on the effects of bergamot on lipid parameters based on studies involving animals and humans.

MAIN EVIDENCE

This natural supplement may lead to effective lipid-lowering treatment. Its lipid-lowering activity is attributed to different flavonoids. However, the exact mechanisms involved remain unclear.

CONCLUSION

It is expected that ongoing and future studies will confirm the benefit of bergamot in dyslipidemic and other cardiometabolic disorders, potentially leading to reduced overall CV risk.

Therapeutic Efficacy of Stem Cells Transplantation in Diabetes: Role of Heme Oxygenase

The growing data obtained from in vivo studies and clinical trials demonstrated the benefit of adult stem cells transplantation in diabetes; although an important limit is represented by their survival after the transplant. To this regard, recent reports suggest that genetic manipulation of stem cells prior to transplantation can lead to enhanced survival and better engraftment. The following review proposes to stimulate interest in the role of heme oxygenase-1 over-expression on transplantation of stem cells in diabetes, focusing on the clinical potential of heme oxygenase protein and activity to restore tissue damage and/or to improve the immunomodulatory properties of transplanted stem cells.

Circulating miR-130a, miR-27b, and miR-210 in Patients With Peripheral Artery Disease and Their Potential Relationship With Oxidative Stress

Some emerging risk factors such as oxidative stress biomarkers and microRNAs (miRs) may add additional value to the established risk factors for peripheral artery disease (PAD). We enrolled 27 patients with PAD and 27 age-matched controls. We examined the levels of a series of miRs (miR-130a, miR-27b, and miR-210) in serum samples. The level of well-established oxidative stress biomarkers, such as lipid hydroperoxides, isoprostanes, hemeoxygenase-1 (HO-1) and reduced glutathione, was also measured in plasma and their relationship with the miRs was determined. Levels of miR-130a, miR-27b, and miR-210 were significantly increased in patients with PAD when compared to the controls. The level of miR-130 was positively correlated with body mass index, whereas miR-210 was inversely associated with pain-free walking distance (PfWD). None of the evaluated miRs was associated with lowered PfWD of patients with PAD (stage IIa > 250 m, IIb < 250 m) or oxidative stress parameters. In conclusion, our findings suggest the need for more research to assess if miRs can serve as useful markers for the early diagnosis and monitoring of PAD.

Immunological reaction and oxidative stress after light or heavy polypropylene mesh implantation in inguinal hernioplasty: A CONSORT-prospective, randomized, clinical trial

The relationship between mesh weight and host tissue reaction has, so far, not been fully investigated. Lightweight meshes (LWM) are thought to give less inflammatory response compared with heavyweight meshes (HWM). The present study is a randomized, controlled, double-blind clinical trial performed in 61 patients who underwent an elective inguinal hernioplasty. The primary outcome of the study was to investigate the relationship between total amount of prosthetic material (polypropylene), immunological reaction, and oxidative stress. The study was double-blinded. Sixty-one patients were recruited for the study and randomly assigned to 2 groups (groups A and B). Levels of inflammation markers (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]) and oxidative stress markers (reduced glutathione [GSH] and lipid hydroperoxides [LOOH]) were determined preoperatively and after undergoing inguinal hernioplasty (after 6, 72, and 288 hours), respectively, with LWM and HWM. There was no significant difference in IL-6 levels between HWM and LWM (P = 0.3, 0.7, 0.8 after 6, 72, and 288 hours, respectively). A statistically significant difference was found after 72 hours for TNF-α (P = 0.01), for GSH after 6 hours (P < 0.01), and after 6 and 72 hours for LOOH (P = 0.05, 0.01, respectively). Oxidative stress occurred at earlier time points and was pore accentuated HWM versus LWM and prodromal to TNF-α increase.Also, in randomized clinical trial, the use of LWM gives advantages in terms of less inflammatory response when compared with HWM. Moreover, there is a significant higher oxidative stress after implantation of HWM. The intensity of oxidative stress seems to be strongly related to the amount of implanted polypropylene. (

TRIAL REGISTRATION NUMBER

NCT01090284).

Olive Leaf Extract from Sicilian Cultivar Reduced Lipid Accumulation by Inducing Thermogenic Pathway during Adipogenesis

Olive leaves contain a wide variety of phenolic compounds belonging to phenolic acids, phenolic alcohols, flavonoids, and secoiridoids, and include also many other pharmacological active compounds. They could play an important role in human diet and health because of their ability to lower blood pressure, increase coronary arteries blood flow and decrease the risk of cardiovascular diseases. The aim of this study was to investigate the effect of olive leaf extract (OLE) from Sicilian cultivar on adipogenic differentiation of human adipose derived mesenchymal stem cells and its impact on lipid metabolism. We showed that OLE treatment during adipogenic differentiation reduces inflammation, lipid accumulation and induces thermogenesis by activation of uncoupling protein uncoupling protein 1, sirtuin 1, peroxisome proliferator-activated receptor alpha, and coactivator 1 alpha. Furthermore, OLE significantly decreases the expression of molecules involved in adipogenesis and upregulates the expression of mediators involved in thermogenesis and lipid metabolism. Taken together, our results suggest that OLE may promote the brown remodeling of white adipose tissue inducing thermogenesis and improving metabolic homeostasis.

Modification of Caffeic Acid with Pyrrolidine Enhances Antioxidant Ability by Activating AKT/HO-1 Pathway in Heart

Overproduction of free radicals during ischemia/reperfusion (I/R) injury leads to an interest in using antioxidant therapy. Activating an endogenous antioxidant signaling pathway is more important due to the fact that the free radical scavenging behavior in vitro does not always correlate with a cytoprotection effect in vivo. Caffeic acid (CA), an antioxidant, is a major phenolic constituent in nature. Pyrrolidinyl caffeamide (PLCA), a derivative of CA, was compared with CA for their antioxidant and cytoprotective effects. Our results indicate that CA and PLCA exert the same ability to scavenge DPPH in vitro. In response to myocardial I/R stress, PLCA was shown to attenuate lipid peroxydation and troponin release more than CA. These responses were accompanied with a prominent elevation in AKT and HO-1 expression and a preservation of mnSOD expression and catalase activity. PLCA also improved cell viability and alleviated the intracellular ROS level more than CA in cardiomyocytes exposed to H₂O₂. When inhibiting the AKT or HO-1 pathways, PLCA lost its ability to recover mnSOD expression and catalase activity to counteract with oxidative stress, suggesting AKT/HO-1 pathway activation by PLCA plays an important role. In addition, inhibition of AKT signaling further abolished HO-1 activity, while inhibition of HO-1 signaling attenuated AKT expression, indicating cross-talk between the AKT and HO-1 pathways. These protective effects may contribute to the cardiac function improvement by PLCA. These findings provide new insight into therapeutic approaches using a modified natural compound against oxidative stress from myocardial injuries.

Caffeic Acid Phenethyl Ester Regulates PPAR's Levels in Stem Cells-Derived Adipocytes

Hypertrophic obesity inhibits activation of peroxisome proliferators-activated receptor gamma (PPARγ), considered the key mediator of the fully differentiated and insulin sensitive adipocyte phenotype. We examined the effects of Caffeic Acid Phenethyl Ester (Cape), isolated from propolis, a honeybee hive product, on Adipose Stem Cells (ASCs) differentiation to the adipocyte lineage. Finally we tested the effects of Cape on insulin-resistant adipocytes. Quantification of Oil Red O-stained cells showed that lipid droplets decreased following Cape treatment as well as radical oxygen species formation. Additionally, exposure of ASC to high glucose levels decreased adiponectin and increased proinflammatory cytokines mRNA levels, which were reversed by Cape-mediated increase of insulin sensitivity. Cape treatment resulted in decreased triglycerides synthesis and increased beta-oxidation. Exposure of ASCs to Lipopolysaccharide (LPS) induced a reduction of PPARγ, an increase of IL-6 levels associated with a well-known stimulation of lipolysis; Cape partially attenuated the LPS-mediated effects. These observations reveal the main role of PPARγ in the adipocyte function and during ASC differentiation. As there is now substantial interest in functional food and nutraceutical products, the observed therapeutic value of Cape in insulin-resistance related diseases should be taken into consideration.

Codon-biased translation can be regulated by wobble-base tRNA modification systems during cellular stress responses

tRNA (tRNA) is a key molecule used for protein synthesis, with multiple points of stress-induced regulation that can include transcription, transcript processing, localization and ribonucleoside base modification. Enzyme-catalyzed modification of tRNA occurs at a number of base and sugar positions and has the potential to influence specific anticodon-codon interactions and regulate translation. Notably, altered tRNA modification has been linked to mitochondrial diseases and cancer progression. In this review, specific to Eukaryotic systems, we discuss how recent systems-level analyses using a bioanalytical platform have revealed that there is extensive reprogramming of tRNA modifications in response to cellular stress and during cell cycle progression. Combined with genome-wide codon bias analytics and gene expression studies, a model emerges in which stress-induced reprogramming of tRNA drives the translational regulation of critical response proteins whose transcripts display a distinct codon bias. Termed Modification Tunable Transcripts (MoTTs), (1) we define them as (1) transcripts that use specific degenerate codons and codon biases to encode critical stress response proteins, and (2) transcripts whose translation is influenced by changes in wobble base tRNA modification. In this review we note that the MoTTs translational model is also applicable to the process of stop-codon recoding for selenocysteine incorporation, as stop-codon recoding involves a selective codon bias and modified tRNA to decode selenocysteine during the translation of a key subset of oxidative stress response proteins. Further, we discuss how in addition to RNA modification analytics, the comprehensive characterization of translational regulation of specific transcripts requires a variety of tools, including high coverage codon-reporters, ribosome profiling and linked genomic and proteomic approaches. Together these tools will yield important new insights into the role of translational elongation in cell stress response.

Combined inhibition of Hsp90 and heme oxygenase-1 induces apoptosis and endoplasmic reticulum stress in melanoma

Heat shock proteins are ubiquitous molecular chaperones involved in post-translational folding, stability, activation and maturation of many proteins that are essential mediators of signal transduction and cell cycle progression. Heat shock protein 90 (Hsp90) has recently emerged as an attractive therapeutic target in cancer treatment since it may act as a key regulator of various oncogene products and cell-signaling molecules. Heme oxygenase-1 (HO-1; also known as Hsp32) is an inducible enzyme participating in heme degradation and involved in oxidative stress resistance. Recent studies indicate that HO-1 activation may play a role in tumor development and progression. In the present study we investigated the chemotherapic effects of combining an Hsp90 inhibitor (NMS E973) and an HO-1 inhibitor (SnMP) on A375 melanoma cells. NMS E973 treatment was able to reduce cell viability and induce endoplasmic reticulum (ER) stress (i.e. Ire1α, ERO1, PDI, BIP and CHOP). Interestingly, no significant effect was observed in reactive oxygen species (ROS) formation. Finally, NMS E973 treatment resulted in a significant HO-1 overexpression, which in turn serves as a possible chemoresistance molecular mechanism. Interestingly, the combination of NMS E973 and SnMP produced an increase of ROS and reduced cell viability compared to NMS E973 treatment alone. The inhibitors combination exhibited higher ER stress, apoptosis as evidenced by bifunctional apoptosis regulator (BFAR) mRNA expression and lower phosphorylation of Akt when compared to NMS E973 alone. In conclusion, these data suggest that HO-1 inhibition potentiates NMS E973 toxicity and may be exploited as a strategy for melanoma treatment.

Diagnosis and Therapy of Atrial Fibrillation: The Past, The Present and The Future

Atrial fibrillation (AF) is the most common age-related cardiac arrhythmia. It is a progressive disease, which makes treatment difficult. The progression of AF is caused by the accumulation of damage in cardiomyocytes which makes the atria more vulnerable for AF. Especially structural remodeling and electrical remodeling, together called electropathology are sustainable in the atria and impair functional recovery to sinus rhythm after cardioversion. The exact electropathological mechanisms underlying persistence of AF are at present unknown. High resolution wavemapping studies in patients with different types of AF showed that longitudinal dissociation in conduction and epicardial breakthrough were the key elements of the substrate of longstanding persistent AF. A double layer of electrically dissociated waves propagating transmurally can explain persistence of AF (Double Layer Hypothesis) but the molecular mechanism is unknown. Derailment of proteasis -defined as the homeostasis in protein synthesis, folding, assembly, trafficking, guided by chaperones, and clearance by protein degradation systems - may play an important role in remodeling of the cardiomyocyte. As current therapies are not effective in attenuating AF progression, step-by-step analysis of this process, in order to identify potential targets for drug therapy, is essential. In addition, novel mapping approaches enabling assessment of the degree of electropathology in the individual patient are mandatory to develop patient-tailored therapies. The aims of this review are to 1) summarize current knowledge of the electrical and molecular mechanisms underlying AF 2) discuss the shortcomings of present diagnostic instruments and therapeutic options and 3) to present potential novel diagnostic tools and therapeutic targets.

Oxidative stress markers at birth: Analyses of a neonatal population

In order to further understand neonatal stress and, thus, control it efficaciously, there is a need for more information on the manifestations of stress at the molecular level in the newborn, with particular regard to oxidants, and anti-oxidant and anti-stress mechanisms, including mitochondrial heat shock protein-chaperones such as Hsp60. We investigated patterns of anti-oxidants, biomarkers of oxidative stress, and Hsp60 levels in sera from newborns and found significant associations between glutathione (GSH) levels and gestational age, delivery modality, and lipid hydroperoxydes (LOOH) level. LOOH levels and spontaneous (vaginal) delivery were independently associated with increased GSH levels when these were above the median. Hsp60 and LOOH levels were positively correlated whereas Hsp60 and GSH levels were inversely correlated in spontaneously delivered newborns; in contrast, Hsp60 and GSH levels were positively correlated in newborns delivered by cesarea. Our results point to new directions in the search for definite patterns of GSH, LOOH, and Hsp60 in the newborn's serum that might have functional and diagnostic significance and that could help in the monitoring of newborn health during and after delivery. In addition, the data provide a starting basis for investigating the precise roles and interplay of GSH and Hsp60 in the maintenance of an optimal redox balance at birth to cope with the stress inherent to delivery, and also for investigating the predictive value of any given pattern of GSH, LOOH, and Hsp60 at birth with regard to health status and risk of disease in adult life.

Effects of Tithonia diversifolia (Hemsl.) A. Gray extract on adipocyte differentiation of human mesenchymal stem cells

Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) is widely used in traditional medicine. There is increasing interest on the in vivo protective effects of natural compounds contained in plants against oxidative damage caused from reactive oxygen species. In the present study the total phenolic and flavonoid contents of aqueous, methanol and dichloromethane extracts of leaves of Tithonia diversifolia (Hemsl.) A. Gray were determined; furthermore, free radical scavenging capacity of each extract and the ability of these extracts to inhibit in vitro plasma lipid peroxidation were also evaluated. Since oxidative stress may be involved in trasformation of pre-adipocytes into adipocytes, to test the hypothesis that Tithonia extract may also affect adipocyte differentiation, human mesenchymal stem cell cultures were treated with Tithonia diversifolia aqueous extract and cell viability, free radical levels, Oil-Red O staining and western bolt analysis for heme oxygenase and 5'-adenosine monophoshate-activated protein kinase were carried out. Results obtained in the present study provide evidence that Tithonia diversifolia (Hemsl.) A. Gray exhibits interesting health promoting properties, resulting both from its free radical scavenger capacity and also by induction of protective cellular systems involved in cellular stress defenses and in adipogenesis of mesenchymal cells.

Liraglutide reduces oxidative stress and restores heme oxygenase-1 and ghrelin levels in patients with type 2 diabetes: a prospective pilot study

CONTEXT

Liraglutide is a glucagon-like peptide-1 analog and glucose-lowering agent whose effects on cardiovascular risk markers have not been fully elucidated.

OBJECTIVE

We evaluated the effect of liraglutide on markers of oxidative stress, heme oxygenase-1 (HO-1), and plasma ghrelin levels in patients with type-2 diabetes mellitus (T2DM).

DESIGN AND SETTING

A prospective pilot study of 2 months' duration has been performed at the Unit of Diabetes and Cardiovascular Prevention at University of Palermo, Italy. Patients and Intervention(s): Twenty subjects with T2DM (10 men and 10 women; mean age: 57 ± 13 y) were treated with liraglutide sc (0.6 mg/d for 2 wk, followed by 1.2 mg/d) in addition to metformin (1500 mg/d orally) for 2 months. Patients with liver disorders or renal failure were excluded.

MAIN OUTCOME MEASURE(S)

Plasma ghrelin concentrations, oxidative stress markers, and heat-shock proteins, including HO-1 were assessed.

RESULTS

The addition of liraglutide resulted in a significant decrease in glycated hemoglobin (HbA1c) (8.5 ± 0.4 vs 7.5 ± 0.4%, P < .0001). In addition, plasma ghrelin and glutathione concentrations increased (8.2 ± 4.1 vs 13.6 ± 7.3 pg/ml, P = .0007 and 0.36 ± 0.06 vs 0.44 ± 0.07 nmol/ml, P = .0002, respectively), whereas serum lipid hydroperoxides and HO-1 decreased (0.11 ± 0.05 vs 0.04 ± 0.07 pg/ml, P = .0487 and 7.7 ± 7.7 vs 3.6 ± 1.8 pg/ml, P = .0445, respectively). These changes were not correlated with changes in fasting glycemia or HbA1c.

CONCLUSIONS

In a 2-months prospective pilot study, the addition of liraglutide to metformin resulted in improvement in oxidative stress as well as plasma ghrelin and HO-1 concentrations in patients with T2DM. These findings seemed to be independent of the known effects of liraglutide on glucose metabolism.

Heat shock proteins and cardiovascular disease

Atherosclerosis is the leading global cause of mortality, morbidity, and disability. Heat shock proteins (HSPs) are a highly conserved family of proteins with diverse functions expressed by all cells exposed to environmental stress. Studies have reported that several HSPs may be potential risk markers of atherosclerosis and related cardiovascular diseases, or may be directly involved in the atherogenic process itself. HSPs are expressed by cells in atherosclerotic plaque and anti-HSP has been reported to be increased in patients with vascular disease. Autoimmune responses may be generated against antigens present within the atherosclerotic plaque, including HSP and may lead to a cycle of ongoing vascular injury. It has been suggested that by inducing a state of tolerance to these antigens, the atherogenic process may be limited and thus provide a potential therapeutic approach. It has been suggested that anti-HSPs are independent predictors of risk of vascular disease. In this review, we summarize the current understanding of HSP in cardiovascular disease and highlight their potential role as diagnostic agents and therapeutic targets.

Immunohistochemical profiling of the heat shock response in obese non-diabetic subjects revealed impaired expression of heat shock proteins in the adipose tissue

BACKGROUND

Obesity is characterized by a chronic low-grade inflammation and altered stress responses in key metabolic tissues. Impairment of heat shock response (HSR) has been already linked to diabetes and insulin resistance as reflected by decrease in heat shock proteins (HSPs) expression. However, the status of HSR in non-diabetic human obese has not yet been elucidated. The aim of the current study was to investigate whether obesity triggers a change in the HSR pattern and the impact of physical exercise on this pattern at protein and mRNA levels.

METHODS

Two groups of adult non-diabetic human subjects consisting of lean and obese (n = 47 for each group) were enrolled in this study. The expression pattern of HSP-27, DNAJB3/HSP-40, HSP-60, HSC-70, HSP72, HSP-90 and GRP-94 in the adipose tissue was primarily investigated by immunohistochemistry and then complemented by western blot and qRT-PCR in Peripheral blood mononuclear cells (PBMCs). HSPs expression levels were correlated with various physical, clinical and biochemical parameters. We have also explored the effect of a 3-month moderate physical exercise on the HSPs expression pattern in obese subjects.

RESULTS

Obese subjects displayed increased expression of HSP-60, HSC-70, HSP-72, HSP-90 and GRP-94 and lower expression of DNAJB3/HSP-40 (P < 0.05). No differential expression was observed for HSP-27 between the two groups. Higher levels of HSP-72 and GRP-94 proteins correlated positively with the indices of obesity (body mass index and percent body fat) and circulating levels of IFN-gamma-inducible protein 10 (IP-10) and RANTES chemokines. This expression pattern was concomitant with increased inflammatory response in the adipose tissue as monitored by increased levels of Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α), and RANTES (P < 0.05). Physical exercise reduced the expression of various HSPs in obese to normal levels observed in lean subjects with a parallel decrease in the endogenous levels of IL-6, TNF-α, and RANTES.

CONCLUSION

Taken together, these data indicate that obesity triggers differential regulation of various components of the HSR in non-diabetic subjects and a 3-month physical moderate exercise was sufficient to restore the normal expression of HSPs in the adipose tissue with concomitant attenuation in the inflammatory response.

Innate immunity and cardiomyocytes in ischemic heart disease

Myocardial ischemia/reperfusion (I/R) is the most common cause of myocardial inflammation, which is primarily a manifestation of the innate immune responses. Innate immunity is activated when pattern recognition receptors (PRRs) respond to molecular patterns common to microbes and to danger signals expressed by injured or infected cells, so called pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). The expression of various PRRs in cardiomyocytes and the release of DAMPs from cardiomyocytes subjected to I/R injury, through active mechanisms as well as passive processes, enable cardiomyocytes to generate innate immune responses. Studies in isolated heart and cardiomyocytes have confirmed the inflammatory and functional effects of cardiac PRRs especially Toll-like receptors in response to I/R-derived DAMPs, such as heat shock proteins. This review addresses the active role of cardiomyocytes in mediating innate inflammatory responses to myocardial I/R. We propose that cardiomyocytes act as innate immune cells in myocardial I/R injury.

Hsp60 chaperonopathies and chaperonotherapy: targets and agents

INTRODUCTION

Hsp60 (Cpn60) assembles into a tetradecamer that interacts with the co-chaperonin Hsp10 (Cpn10) to assist client polypeptides to fold, but it also has other roles, including participation in pathogenic mechanisms.

AREA COVERED

Hsp60 chaperonopathies are pathological conditions, inherited or acquired, in which the chaperone plays a determinant etiologic-pathogenic role. These diseases justify selection of Hsp60 as a target for developing agents that interfere with its pathogenic effects. We provide information on how to proceed.

EXPERT OPINION

The information available encourages the development of ways to improve Hsp60 activity (positive chaperonotherapy) when deficient or to block it (negative chaperonotherapy) when pathogenic. Many questions are still unanswered and obstacles are obvious. More information is needed to establish when and why autologous Hsp60 becomes a pathogenic autoantigen, or induces cytokine formation and inflammation, or favors carcinogenesis. Clarification of these points will take considerable time. However, analysis of the Hsp60 molecule and a search for active compounds aimed at structural sites that will affect its functioning should continue without interruption. No doubt that some of these compounds will offer therapeutic hopes and will also be instrumental for dissecting structure-function relationships at the biochemical and biological (using animal models and cultured cells) levels.

Upregulation of heat shock protein 32 in Sertoli cells alleviates the impairments caused by heat shock-induced apoptosis in mouse testis

Heat stress results in apoptosis in testicular germ cells. A small heat shock protein (hsp), hsp32, is induced by heat stress in the testis, but little is known about its definitive function in physiological processes. To clarify the underlying role of hsp32, hsp32 expression and related signals in the heat shock pathway were analysed in mouse testes and Sertoli cells after heat stress in vivo and in vitro; meanwhile, expression of hsp32 was silenced only in the Sertoli cells using three different small interfering RNAs (siRNAs) to further verify the functional role of hsp32 in Sertoli cells, and hsp32-derived carbon monoxide (CO) contents in cultured media were analysed to clarify whether hsp32-derived CO involve in the apoptosis regulation mechanisms. The results from the in vivo experiment showed that the high expression levels of hsp32 (P < 0.05) were observed whether chronic, moderate or acute, transient heat exposure. The in vitro experiment showed that acute, transient heat exposure resulted in increases in Sertoli cells apoptosis (P < 0.01), the expression of hsp32 and caspase-3 activity; hsp32-siRNA knockdown of hsp32 expression resulted in upregulated apoptosis (P < 0.01) and caspase-3 activity (P < 0.01) in the Sertoli cells and hyperthermia increases CO (P < 0.01) release by Sertoli cells. The results suggested that upregulating hsp32 in Sertoli cells inhibits caspase-3 activity and alleviates heat-induced impairments in mouse testis; hsp32-derived CO may involve in the regulation mechanism.

Beneficial effect of prolonged heme oxygenase 1 activation in a rat model of chronic heart failure

We and others have previously demonstrated that heme oxygenase 1 (HO-1) induction by acute hemin administration exerts cardioprotective effects. Here, we developed a rat model of heart failure to investigate whether a long-term induction of HO-1 by chronic hemin administration exerted protective effects. Sprague Dawley rats that underwent permanent ligation of the left coronary artery were closely monitored for survival rate analysis and sacrificed on day 28 post-operation. Administration of hemin (4 mg/kg body weight) every other day for 4 weeks induced a massive increase in HO-1 expression and activity, as shown by the increased levels of the two main metabolic products of heme degradation, bilirubin and carbon monoxide (CO). These effects were associated with significant improvement in survival and reduced the extension of myocardial damage. The ischemic hearts of the hemin-treated animals displayed reduced oxidative stress and apoptosis in comparison with the non-treated rats, as shown by the decreased levels of lipid peroxidation, free-radical-induced DNA damage, caspase-3 activity and Bax expression. Besides, chronic HO-1 activation suppressed the elevated levels of myeloperoxidase (MPO) activity, interleukin 1β (IL-1β) production and tumor necrosis factor-α (TNFα) production that were evoked by the ischemic injury, and increased the plasma level of the anti-inflammatory cytokine IL-10. Interestingly, HO-1 inhibitor zinc protoporphyrin IX (ZnPP-IX; 1 mg/kg) lowered bilirubin and CO concentrations to control values, thus abolishing all the cardioprotective effects of hemin. In conclusion, the results demonstrate that chronic HO-1 activation by prolonged administration of hemin improves survival and exerts protective effects in a rat model of myocardial ischemia by exerting a potent antioxidant activity and disrupting multiple levels of the apoptotic and inflammatory cascade.

Extracellular HSP60 induces inflammation through activating and up-regulating TLRs in cardiomyocytes

AIMS

The molecular events leading from cardiomyocyte ischaemia to inflammatory cytokine production are not well understood. We previously found that heat shock protein 60 (HSP60) appeared in extracellular space after cardiomyocyte ischaemia. This study examined the activation and regulation of toll-like receptors (TLRs) by HSP60 in cardiomyocytes.

METHODS AND RESULTS

Cytokine production and TLRs regulation mediated by TLRs signalling were examined in response to exogenous HSP60 (exHSP60) and endogenous HSP60 (enHSP60) released extracellularly under ischaemia. The results showed that exHSP60 induced inflammatory cytokine production in adult rat cardiomyocytes and H9c2 cells (a standard cardiac cell line derived from embryonic cells), through a pathway dependent on TLR4, myeloid differentiation factor 88 (MyD88), p38, and nuclear factor-κB (NF-κB). Further study revealed up-regulated expression of both TLR2 and TLR4 by exHSP60, which was dependent on the activation of TLR4, MyD88, c-Jun NH2-terminal kinase (JNK), and NF-κB, but not on p38. In myocytes exposed to ischaemia, enHSP60 was released into the media, and triggered cytokine production and TLR2/4 overexpression, through the same pathways as exHSP60. In rats subjected to LAD ligation, the released enHSP60 contributed to cytokine production and TLR2/4 overexpression in the ischaemic myocardium.

CONCLUSION

Extracellular HSP60 induces cytokine production via TLR4-MyD88-p38/NF-κB pathway, and up-regulates TLR2/4 expression via TLR4-MyD88-JNK/NF-κB pathway. Both pathways contribute to myocardial inflammation induced by ischaemia.

Effects of intracoronary delivery of allogenic bone marrow-derived stem cells expressing heme oxygenase-1 on myocardial reperfusion injury

Heme oxygenase-1 (HO-1) decreases apoptosis, inflammation and oxidative stress. The aim of the study was to investigate the effects of intracoronary infusion of allogenic bone marrow cells (BMC) overexpressing HO-1 in the porcine model of myocardial infarction (MI). MI was produced by balloon occlusion of a coronary artery. BMC were transduced with adenoviruses encoding for HO-1 (HO-1 BMC) or GFP (GFP-BMC) genes. Prior to reperfusion animals received HO-1 BMC, control BMC (unmodified or GFP-BMC) or placebo. Left ventricular (LV) ejection fraction (EF), shortening fraction (SF), end-systolic and end-diastolic diameters (EDD, ESD) were assessed by echocardiography before, 30 minutes (min) and 14 days after reperfusion. BMC significantly improved LVEF and SF early (30 min) after reperfusion as well as after 14 days. Early after reperfusion HO-1 BMC were significantly more effective than control BMC, but after 14 days, there were no differences. There were no effect of cells on LV remodelling and diastolic function. Both HO-1 BMC and control BMC significantly reduced the infarct size vs. placebo (17.2 ± 2.7 and 18.8 ± 2.5, respectively, vs. 27.5 ± 5.1, p= 0.02) in histomorphometry. HO-1-positive donor BMC were detected in the infarct border area in pigs receiving HO-1-cells. No significant differences in expression of inflammatory genes (SDF-1, TNF-α, IL-6, miR21, miR29a and miR133a) in the myocardium were found. In conclusion, intracoronary delivery of allogeneic BMC immediately prior to reperfusion improved the LVEF and reduced the infarct size. HO-1 BMC were not superior to control cells after 14 days, however, produced faster recovery of LVEF. Transplanted cells survived in the peri-infarct zone.

Translational infidelity-induced protein stress results from a deficiency in Trm9-catalyzed tRNA modifications

Correct codon-anticodon pairing promotes translational fidelity, with these interactions greatly facilitated by modified nucleosides found in tRNA. We hypothesized that wobble uridine modifications catalyzed by tRNA methyltransferase 9 (Trm9) are essential for translational fidelity. In support, we have used phenotypic, reporter and protein-based assays to demonstrate increased translational infidelity in trm9Δ Saccharomyces cerevisiae cells. Codon reengineering studies suggest that Trm9-catalyzed tRNA modifications promote fidelity during the translation of specific genes, those rich in arginine and glutamic acid codons from mixed boxes. Using quantitative tRNA modification analysis, we determined that trm9Δ cells are only deficient in 2 of 23 tRNA modifications, with those 2, 5-methoxycarbonylmethyluridine (mcm ( 5) U) and 5-methoxycarbonylmethyl-2-thiouridine (mcm ( 5) s ( 2) U), classified as key determinants of translational fidelity. We also show that in the absence of mcm ( 5) U and mcm ( 5) s ( 2) U, the resulting translational infidelity promotes protein errors and activation of unfolded protein and heat shock responses. These data support a model in which Trm9-catalyzed tRNA modifications promote fidelity during the translation of specific transcripts, with decreased wobble base modification leading to translational infidelity, protein errors and activation of protein stress response pathways.

Heat-shock protein 60 kDa and atherogenic dyslipidemia in patients with untreated mild periodontitis: a pilot study

Identification of predictors of cardiovascular risk can help in the prevention of pathologic episodes and the management of patients at all stages of illness. Here, we investigated the relationships between serum levels of Hsp60 and dyslipidemia in patients with periodontitis by performing a cross-sectional study of 22 patients with mild periodontitis without any prior treatment for it (i.e., drug naïve) and 22 healthy controls, matched for age and body mass index (BMI). All subjects were evaluated for periodontal status, gingival inflammation, and oral hygiene. Levels of circulating Hsp60, C-reactive protein (CRP), and plasma lipids were measured, and small, dense low-density lipoproteins (LDL) were indirectly assessed by determining the triglycerides/high-density lipoproteins (HDL) cholesterol ratio. We also assessed by immunohistochemistry Hsp60 levels in oral mucosa of patients and controls. No difference was found in CRP levels or plasma lipids between the two groups, but subjects with periodontitis showed, in comparison to controls, higher levels of small, dense LDL (p  = 0.0355) and circulating Hsp60 concentrations (p < 0.0001). However, levels of mucosal Hsp60 did not change significantly between groups. Correlation analysis revealed that circulating Hsp60 inversely correlated with HDL-cholesterol (r  = -0.589, p  = 0.0039), and positively with triglycerides (r  = +0.877, p < 0.0001), and small, dense LDL (r  = +0.925, p < 0.0001). Serum Hsp60 significantly correlated with the degree of periodontal disease (r  = +0.403, p  = 0.0434). In brief, untreated patients with mild periodontitis had increased small, dense LDL and serum Hsp60 concentrations, in comparison to age- and BMI-matched controls and both parameters showed a strong positive correlation. Our data indicate that atherogenic dyslipidemia and elevated circulating Hsp60 tend to be linked and associated to periodontal pathology. Thus, the road is open to investigate the potential value of elevated levels of circulating Hsp60 as predictor of risk for cardiovascular disease when associated to dyslipidemia in periodontitis patients.