Tumor Necrosis Factor-α and C-C Motif Chemokine Ligand 18 Associate with Atherosclerotic Lipid Accumulation In situ and In vitro.

Atherosclerosis is regarded as a chronic inflammatory disease associated with changes in the innate immune system functioning and cytokine disturbances. Local inflammation in the arterial wall is an important component in the development and growth of atherosclerotic plaques. Inside the lesions, both pro- and antiinflammatory cytokines were detected, highlighting the complexity of the atherosclerotic process. However, little is known about the expression of these signaling molecules in early human atherosclerotic lesions. In this study, we explored localization of a pro-inflammatory cytokine, tumor necrosis factor-α (TNFα), and anti-inflammatory chemokine, C-C motif chemokine ligand 18 (CCL18), in the arterial wall of human aorta. We noticed differences in the intensity of staining for TNFα and CCL18 in atherosclerotic lesions and grossly normal areas, as well as differences in their localization. While CCL18 prevailed in the areas close to the aortic lumen, TNFα was localized in deeper layers of the intima. We next studied the expression of TNFα and CCL18 mRNA in lesions corresponding to different stages of atherosclerosis progression and found that it was maximal in lipofibrous plaques that are most enriched in lipids. To test the hypothesis that cytokine expression can be associated with lipid accumulation, we studied the TNFα and CCL18 expression profiles in primary human monocyte-derived macrophages after inducing lipid accumulation by incubating cultured cells with atherogenic LDL. We found that intracellular cholesterol accumulation was associated with upregulation of both TNFα and CCL18, confirming our hypothesis. These results encourage further investigation of cytokine expression in human atherosclerotic lesions and its role in the atherosclerosis progression.

Chemokines and Relevant microRNAs in the Atherogenic Process.

Chemokines play a significant role in initial and advanced steps of atherogenesis. In early steps, chemokines control the adhesion of leukocytes to endothelial cells (ECs) followed by transmigration of monocytes and their deposition in the intima where they differentiate to proinflammatory macrophages. Except for proinflammatory activity, chemokines are responsible for homeostasis and homing of progenitor cells. Recently, microRNAs (miRs) were found to control expression and activity of chemokines in ECs, vascular smooth muscle cells (VSMCs), and macrophages at different steps of atherogenesis. Expression of the proatherogenic chemokine CXCL1 is suppressed by miR-181 that down-regulates nuclear transcription factor NF-kB stimulation in ECs therefore weakening the adhesiveness of the endothelium for monocytes. MiR-126 activates the endothelial production of a chemokine CXCL12 via self-multiplying feedback loop to promote re-endothelialization and support lesion stability. MiR-155 is proatherogenic by induction of the inflammatory chemokine CCL2 in macrophages. In fact, chemokines, their receptors, and relevant miRs form a complex network that exerts pro- and anti-inflammatory properties in vascular cells during different steps of atherogenic process. Obtaining new information about complicated relations between miRs and chemokines may create prerequisites for the development of novel approaches to treat atherosclerosis.

Engineered Nanoparticles: Their Properties and Putative Applications for Therapeutic Approaches Utilizing Stem Cells for the Repair of Atherosclerotic Disease.

BACKGROUND: Stem cell therapy was established as a promising approach for regenerative medicine applications such as cardiac repair. However, current stem cell-based therapeutic strategies have serious challenges such as low retention and viability of transplanted stem cells in the injured myocardium. This significantly limits efficiency of stem cell therapy. In addition, poor knowledge about the fate and survival of stem cells after transplantation represents a major reason of conflicting results from recent clinical studies. OBJECTIVE: The purpose of review is to highlight key properties and possible applications of nanoparticles for therapeutic approaches utilizing stem cells for cardiac repair. RESULTS: Nanoparticles that are widely used in various biomedical applications may serve as a valuable tool for overcoming these obstacles. Various types of nanoparticles could be efficiently used for delivery of genes that enhance survival and regenerative capacity and decrease apoptosis of transplanted stem cells in the adverse ischemic microenvironment. Furthermore, modification of nanoparticles with chemical agents and/or specific proteins and peptides greatly increases the possibility of targeted transfer of a cargo. Nanoparticles can also greatly facilitate in vivo monitoring of stem cell tracking. Using multimodality hybrid nanosized agents, it is possible to obtain detailed characterization of the post-transplantation behavior of stem cell engrafts. CONCLUSION: Using of nanocarriers may be very helpful to trigger the efficiency of cardiovascular stem cell biology. It is important however to keep in the mind safety and compatibility of implementation of nanoparticles to proceed to clinical trials.

The impact of interferon-regulatory factors to macrophage differentiation and polarization into M1 and M2.

The mononuclear phagocytes control the body homeostasis through the involvement in resolving tissue injury and further wound healing. Indeed, local tissue microenvironmental changes can significantly influence the functional behavior of monocytes and macrophages. Such microenvironmental changes for example occur in an atherosclerotic plaque during all progression stages. In response to exogenous stimuli, macrophages show a great phenotypic plasticity and heterogeneity. Exposure of monocytes to inflammatory or anti-inflammatory conditions also induces predominant differentiation to proinflammatory (M1) or anti-inflammatory (M2) macrophage subsets and phenotype switch between macrophage subsets. The phenotype transition is accompanied with great changes in the macrophage transcriptome and regulatory networks. Interferon-regulatory factors (IRFs) play a key role in hematopoietic development of monocytes, their differentiation to macrophages, and regulating macrophage maturation, phenotypic polarization, phenotypic switch, and function. Of 9 IRFs, at least 3 (IRF-1, IRF-5, and IRF-8) are involved in the commitment of proinflammatory M1 whereas IRF-3 and IRF-4 control M2 polarization. The role of IRF-2 is context-dependent. The IRF impact on macrophage phenotype plasticity and heterogeneity is complex and involves activating and repressive function in triggering transcription of target genes.

Epigenetic Alterations in DNA and Histone Modifications Caused by Depression and Antidepressant Drugs: Lessons from the Rodent Models.

Epigenetic modifications regulate chromatin folding and function. Epigenetic mechanisms regulate transcription mediating effects of various stimuli on gene expression. These mechanisms are involved in transcriptional control in various physiological and pathological conditions including neuropsychiatric disorders and behavioral abnormalities such as depression. In rodents, exposure to chronic social stress was shown to induce behavioral impairments and memory/learning deficits that resemble depressive-like phenotype in humans. The rodent models of chronic stress were widely used to study molecular mechanisms of depression. In these models, early exposure to chronic stress such as prenatal or postnatal stress induces long-term hyperactive stress responses, behavioral abnormalities, and functional impairments in brain function that persist in adulthood. Furthermore, these alterations can be transmitted to offspring of chronically stressed animals across several generations. Molecular studies in animal models showed that chronic stress induces stable epigenetic changes in specific brain regions, primarily in the limbic system. These changes lead to long-lasting abnormalities in behavior that persist in adulthood and can be transmitted to offspring. Treatment with epigenetically active antidepressants disrupts the abnormal stress-induced epigenetic programming and provides epigenetic patterns that resemble epigenetic background of stress resilient individuals.

The impact of FOXO-1 to cardiac pathology in diabetes mellitus and diabetes-related metabolic abnormalities.

Diabetic heart pathology has a serious social impact due to high prevalence worldwide and significant mortality/invalidation of diabetic patients suffered from cardiomyopathy. The pathogenesis of diabetic and diabetes-related cardiomyopathy is associated with progressive loss and impairment of cardiac function due to adverse effects of metabolic, prooxidant, proinflammatory, and pro-apoptotic stress factors. In the adult heart, the transcriptional factor forkhead box-1 (FOXO-1) is involved in maintaining cardiomyocytes in the homeostatic state and induction of their adaptation to metabolic and pro-oxidant stress stimuli. Insulin inhibits cardiac FOXO-1 expression/activity through the IRS1/Akt signaling in order to prevent gluconeogenesis. In diabetes and insulin resistance, both insulin production and insulin-dependent signaling is weakened or absent. Indeed, FOXO-1 becomes overproduced/overactivated in response to stress stimuli. In diabetic cardiac tissue, FOXO-1 overactivity induces the metabolic switch from the glucose uptake to the predominant lipid uptake. FOXO-1 limits mitochondrial glucose oxidation by stimulation of pyruvate dehydrogenase kinase 4 (PDK4) and increases the lipid uptake through up-regulation of surface expression of CD36. In cardiac muscle cells, lipid accumulation leads to lipotoxicity via increased lipid oxidation, oxidative stress, and cardiomyocyte apoptosis. Indeed, cardiac FOXO-1 levels and activity should be strictly regulated. FOXO-1 deregulation (that is observed in the diabetic heart) causes detrimental effects that finally lead to heart failure.

Novel Aberrations Uncovered in Barrett's Esophagus and Esophageal Adenocarcinoma Using Whole Transcriptome Sequencing.

Esophageal adenocarcinoma (EAC) has one of the fastest increases in incidence of any cancer, along with poor five-year survival rates. Barrett's esophagus (BE) is the main risk factor for EAC; however, the mechanisms driving EAC development remain poorly understood. Here, transcriptomic profiling was performed using RNA-sequencing (RNA-seq) on premalignant and malignant Barrett's tissues to better understand this disease. Machine-learning and network analysis methods were applied to discover novel driver genes for EAC development. Identified gene expression signatures for the distinction of EAC from BE were validated in separate datasets. An extensive analysis of the noncoding RNA (ncRNA) landscape was performed to determine the involvement of novel transcriptomic elements in Barrett's disease and EAC. Finally, transcriptomic mutational investigation of genes that are recurrently mutated in EAC was performed. Through these approaches, novel driver genes were discovered for EAC, which involved key cell cycle and DNA repair genes, such as BRCA1 and PRKDC. A novel 4-gene signature (CTSL, COL17A1, KLF4, and E2F3) was identified, externally validated, and shown to provide excellent distinction of EAC from BE. Furthermore, expression changes were observed in 685 long noncoding RNAs (lncRNA) and a systematic dysregulation of repeat elements across different stages of Barrett's disease, with wide-ranging downregulation of Alu elements in EAC. Mutational investigation revealed distinct pathways activated between EAC tissues with or without TP53 mutations compared with Barrett's disease. In summary, transcriptome sequencing revealed altered expression of numerous novel elements, processes, and networks in EAC and premalignant BE.Implications: This study identified opportunities to improve early detection and treatment of patients with BE and esophageal adenocarcinoma. Mol Cancer Res; 15(11); 1558-69. ©2017 AACR.

The effect of maximal vs submaximal exertion on postprandial lipid levels in individuals with and without coronary heart disease.

BACKGROUND: Decisions about fat consumption and levels of physical activity are among the everyday choices we make in life and risk of coronary heart disease (CHD) can be affected by those choices. OBJECTIVE: The purpose of this study was to investigate the influence of a standard fat load combined with physical exertion of different intensities on the plasma lipid profile of CHD patients and CHD-free individuals. METHODS: This study looked at the influence of different intensities of physical exercise on postprandial lipid metabolism in 20 healthy men and 36 men with diagnosis of CHD. Venous blood samples were obtained after overnight fasting, 3 hours after standard fat load (before the physical load), and immediately after maximal or submaximal physical exercise on bicycle ergometer. RESULTS: After fat load total cholesterol (TC) concentration did not change in either group. However, after the addition of maximal exercise, TC, triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein (Apo) B increased significantly (P < .01) in both groups. After fat load and maximal exercise, there was no change in high-density lipoprotein cholesterol (HDL-C) in healthy men, but in men with CHD, HDL-C fell significantly (P < .01); and Apo AI rose in healthy men (P < .01) but dropped significantly (P < .01) in men with CHD. Submaximal physical exercise (60% of max VO2 load for 40 minutes) after fat load decreased TG level in CHD patients (P < .01) and improved other lipid parameters in both groups significantly (↓LDL-C, ↑HDL-C, ↑Apo AI, ↓Apo B, P < .01). We observed a worsening of physical work capacity in men with CHD (significant reduction of duration and total amount of work performed, maximal VO2, oxygen pulse), during maximal stress test performed 3 hours after fat load. There was a doubling of the number of abnormal stress test results (P < .01). Healthy persons showed an increase in respiratory parameters (ventilation, CO2 production, maximal VO2, and oxygen pulse), but no significant change was found in work capacity. Thus, maximal physical exercise produced atherogenic blood lipid changes (increased TC, increased LDL-C, increased TG, increased Apo B, P < .01) in men with CHD and in healthy men; however, individuals with CHD also demonstrated a significant decrease in HDL-C and Apo AI (P < .01). In contrast, the submaximal physical load improved postprandial lipid changes in both healthy men and men with CHD. CONCLUSIONS: This study demonstrates that moderate exercise is beneficial in improving postprandial lipid abnormalities in both CHD and CHD-free subjects after fatty meal preload. In addition, maximal exercise demonstrated evidence of increase of lipid abnormalities in both CHD and CHD-free individuals under similar conditions of fatty meal preload.

Nanocarriers in Improving Chemotherapy of Multidrug Resistant Tumors: Key Developments and Perspectives.

The multidrug resistance (MDR) of tumor cells significantly reduces the efficiency of traditional anticancer therapy. Tumor MDR is complex and involves several mechanisms such as decreased drug uptake, increased drug efflux, enhanced drug exocytosis, increased drug detoxification and inactivation by drugmetabolizing enzymes, altered drug targets due to genetic and epigenetic modifications, altered DNA repair, and impaired apoptotic pathways. Implementation of nanoparticles can markedly improve drug delivery through increased stability in the plasma, prolonged half-life, enhanced specificity of transfer, and advanced drug accumulation and retention in the tumor cells. So far, many various types of nanocarriers have been used for the delivery of anticancer agents. These carriers greatly increase anti-tumor effects of cytotoxic agents since drug-carrying nanoparticles are able to reverse MDR. The promising integrative approach in cancer nanotherapy assumes the development of multifunctional delivery systems simultaneously transmitting various agents such as drugs, genes, imaging agents, and targeting ligands in order to enhance anti-tumor toxicity and nanoparticle tracking.

Macrophages and Their Contribution to the Development of Atherosclerosis.

Atherosclerosis can be regarded as chronic inflammatory disease driven by lipid accumulation in the arterial wall. Macrophages play a key role in the development of local inflammatory response and atherosclerotic lesion growth. Atherosclerotic plaque is a complex microenvironment, in which different subsets of macrophages coexist executing distinct, although in some cases overlapping functions. According to the classical simplified nomenclature, lesion macrophages can belong to pro-inflammatory or anti-inflammatory or alternatively activated types. While the former promote the inflammatory response and participate in lipid accumulation, the latter are responsible for the inflammation resolution and plaque stabilisation. Atherosclerotic lesion dynamics depends therefore on the balance between these macrophages populations. The diverse functions of macrophages make them an attractive therapeutic target for the development of novel anti-atherosclerotic treatments. In this chapter, we discuss different types of macrophages and their roles in atherosclerotic lesion dynamics and describe the results of several experiments studying macrophage polarisation in atherosclerosis.

The phenomenon of atherosclerosis reversal and regression: Lessons from animal models.

Studies in non-rodent and murine models showed that atherosclerosis can be reversed. Atherosclerosis progression induced by high-fat or cholesterol-rich diet can be reduced and reversed to plaque regression after switching to a normal diet or through administration of lipid-lowering agents. The similar process should exist in humans after implementation of lipid-lowering therapy and as a result of targeting of small rupture-prone plaques that are major contributors for acute atherosclerotic complications. Lowering of low density lipoprotein (LDL) cholesterol and the activation of reverse cholesterol transport lead to a decline in foam cell content, to the depletion of plaque lipid reservoirs, a decrease in lesional macrophage numbers through the activation of macrophage emigration and, probably, apoptosis, dampening plaque inflammation, and the induction of anti-inflammatory macrophages involved in clearance of the necrotic core and plaque healing. By contrast, plaque regression is characterized by opposite events, leading to the retention of atherogenic LDL and oxidized LDL particles in the plaque, an increased flux of monocytes, the immobilization of macrophages in the intimal vascular tissues, and the propagation of intraplaque inflammation. Transfer of various apolipoprotein (apo) genes to spontaneously hypercholesterolemic mice deficient for either apoE or LDL receptor and, especially, the implementation of the transplantation murine model allowed studying molecular mechanisms of atherosclerotic regression, associated with the depletion of atherogenic lipids in the plaque, egress of macrophages and phenotypic switch of macrophages from the proinflammatory M1 to the anti-inflammatory M2.

How do macrophages sense modified low-density lipoproteins?

In atherosclerosis, serum lipoproteins undergo various chemical modifications that impair their normal function. Modification of low density lipoprotein (LDL) such as oxidation, glycation, carbamylation, glucooxidation, etc. makes LDL particles more proatherogenic. Macrophages are responsible for clearance of modified LDL to prevent cytotoxicity, tissue injury, inflammation, and metabolic disturbances. They develop an advanced sensing arsenal composed of various pattern recognition receptors (PRRs) capable of recognizing and binding foreign or altered-self targets for further inactivation and degradation. Modified LDL can be sensed and taken up by macrophages with a battery of scavenger receptors (SRs), of which SR-A1, CD36, and LOX1 play a major role. However, in atherosclerosis, lipid balance is deregulated that induces inability of macrophages to completely recycle modified LDL and leads to lipid deposition and transformation of macrophages to foam cells. SRs also mediate various pathogenic effects of modified LDL on macrophages through activation of the intracellular signaling network. Other PRRs such Toll-like receptors can also interact with modified LDL and mediate their effects independently or in cooperation with SRs.

Treatment of cardiovascular pathology with epigenetically active agents: Focus on natural and synthetic inhibitors of DNA methylation and histone deacetylation.

Cardiovascular disease (CVD) retains a leadership as a major cause of human death worldwide. Although a substantial progress was attained in the development of cardioprotective and vasculoprotective drugs, a search for new efficient therapeutic strategies and promising targets is under way. Modulation of epigenetic CVD mechanisms through administration epigenetically active agents is one of such new approaches. Epigenetic mechanisms involve heritable changes in gene expression that are not linked to the alteration of DNA sequence. Pathogenesis of CVDs is associated with global genome-wide changes in DNA methylation and histone modifications. Epigenetically active compounds that influence activity of epigenetic modulators such as DNA methyltransferases (DNMTs), histone acetyltransferases, histone deacetylases (HDACs), etc. may correct these pathogenic changes in the epigenome and therefore be used for CVD therapy. To date, many epigenetically active natural substances (such as polyphenols and flavonoids) and synthetic compounds such as DNMT inhibitors or HDAC inhibitors are known. Both native and chemical DNMT and HDAC inhibitors possess a wide range of cytoprotective activities such as anti-inflammatory, antioxidant, anti-apoptotic, anti-anfibrotic, and anti-hypertrophic properties, which are beneficial of treatment of a variety of CVDs. However, so far, only synthetic DNMT inhibitors enter clinical trials while synthetic HDAC inhibitors are still under evaluation in preclinical studies. In this review, we consider epigenetic mechanisms such as DNA methylation and histone modifications in cardiovascular pathology and the epigenetics-based therapeutic approaches focused on the implementation of DNMT and HDAC inhibitors.

CD68/macrosialin: not just a histochemical marker.

CD68 is a heavily glycosylated glycoprotein that is highly expressed in macrophages and other mononuclear phagocytes. Traditionally, CD68 is exploited as a valuable cytochemical marker to immunostain monocyte/macrophages in the histochemical analysis of inflamed tissues, tumor tissues, and other immunohistopathological applications. CD68 alone or in combination with other cell markers of tumor-associated macrophages showed a good predictive value as a prognostic marker of survival in cancer patients. Lowression of CD68 was found in the lymphoid cells, non-hematopoietic cells (fibroblasts, endothelial cells, etc), and tumor cells. Cell-specific CD68 expression and differentiated expression levels are determined by the complex interplay between transcription factors, regulatory transcriptional elements, and epigenetic factors. Human CD68 and its mouse ortholog macrosialin belong to the family of LAMP proteins located in the lysosomal membrane and share many structural similarities such as the presence of the LAMP-like domain. Except for a second LAMP-like domain present in LAMPs, CD68/microsialin has a highly glycosylated mucin-like domain involved in ligand binding. CD68 has been shown to bind oxLDL, phosphatidylserine, apoptotic cells and serve as a receptor for malaria sporozoite in liver infection. CD68 is mainly located in the endosomal/lysosomal compartment but can rapidly shuttle to the cell surface. However, the role of CD68 as a scavenger receptor remains to be confirmed. It seems that CD68 is not involved in binding bacterial/viral pathogens, innate, inflammatory or humoral immune responses, although it may potentially be involved in antigen processing/presentation. CD68 could be functionally important in osteoclasts since its deletion leads to reduced bone resorption capacity. The role of CD68 in atherosclerosis is contradictory.

Paraoxonase and atherosclerosis-related cardiovascular diseases.

In humans, three paraoxonase (PON1, PON2, and PON3) genes are clustered on chromosome 7 at a locus that spans a distance around 170 kb. These genes are highly homologous to each other and have a similar protein structural organization. PON2 is the intracellular enzyme, which is expressed in many tissues and organs, while two other members of PON gene family are produced by liver and associate with high density lipoprotein (HDL). The lactonase activity is the ancestral. Besides lactones and organic phosphates, PONs can hydrolyze and therefore detoxify oxidized low density lipoprotein and homocysteine thiolactone, i.e. two cytotoxic compounds with a strong proatherogenic action. Indeed, PONs possess numerous atheroprotective properties, which include antioxidant activity, anti-inflammatory action, preserving HDL function, stimulation of cholesterol efflux, anti-apoptosis, anti-thrombosis, and anti-adhesion. PON genetic polymorphisms contribute to susceptibility/protection from atherosclerosis-related diseases. The bright antiatherogenic activity of the PON cluster makes it a promising target for the development of new therapeutic strategies.

Epigenetically Active Drugs Inhibiting DNA Methylation and Histone Deacetylation.

Epigenetic mechanisms, which are involved in the regulation of gene expression, are tightly controlled. Loss of a proper epigenetic control can lead to global epigenetic alterations frequently observed in various diseases including cancer. Aberrant epigenetic changes induced in malignant cells lead to emergence of neoplastic properties, which inhibit cell differentiation and strict cell cycle control but greatly enhance stemness-related features. However, abnormal epigenetic patterns can be reversed by action of epigenetically active agents. Epigenetic machinery comprises a variety DNA/histone modifiers and chromatin remodelers. Chemical substances able to influence on the activity of epigenetic factors such as inhibitors of DNA methyltransferases or histone deacetylase inhibitors can be used as therapeutic agents for improving aberrant epigenetic signatures in cancer cells. Preclinical studies showed efficiency of such epigenetic drugs for the treatment of variety of cancers. So far, several epigenetically active compounds were approved for therapy of hematological malignancies. However, many challenges should be resolved for efficient use of epidrugs in the treatment of non-hematological solid tumors and advanced cancers associated with chemoresistance and higher risk of relapse.