Culturing of Cardiac Cells in 3D Spheroids Modulates Their Expression Profile and Increases Secretion of Proangiogenic Growth Factors.

We studied the effect of 3D-culturing of cells in the form of cardiospheres on the expression of genes encoding vascular progenitor cell markers and angiogenesis regulators and on the production of proangiogenic factors. Cardiospheres were obtained by culturing mouse cardiac explants followed by self-assembly on poly-D-lysine. Gene expression was assessed by real-time PCR, and the production of proangiogenic factors was assessed by Microarray analysis of the cell secretome. It was found that cells in the cardiospheres in comparison with 2D-culture of cardiosphere-forming cells demonstrated increased expression of vascular progenitor cell markers (Pdgfrα, Kit, and Vegfr1) and angiogenesis regulatory factors (Vegf, Fgf2, and Angpt1), as well as an enhanced secretion of proangiogenic factors (ANGPT1, VEGF, CXCL16, and PIGF-2). Thus, culturing of cells in the form of cardiospheres can be considered as a basis for developing approaches to increasing their angiogenic activity and regenerative properties.

Deficiency of Urokinase-Type Plasminogen Activator Receptor Is Associated with the Development of Perivascular Fibrosis in Mouse Heart.

It was suggested that the urokinase system plays a certain role in the regulation of activity of the endothelial-mesenchymal transition and in the development of perivascular fibrosis. Urokinase (uPA), the key component of the urokinase system, is a serine protease that binds to its receptor on the cell surface (uPAR) and affects the cell microenvironment components through the formation of plasmin, remodeling of the extracellular matrix, release of growth factors, and initiation of intracellular signals. The heart of PLAUR gene knockout C57BL/129 (uPAR-/-) mice showed signs of vasculopathy: reduced number of capillaries/arterioles, signs of endothelial-mesenchymal transition in endothelial cells, vascular wall remodeling, and deposition of extracellular matrix components. These changes were combined with enhanced expression of urokinase and active forms of TGF-ß1. Apparently, uPAR is a part of a multicomponent system that provides multifaceted regulatory effects on the components of forming vessels and vascular wall cells, which allows considering it as a possible target for targeted antifibrotic therapy.

Features of the Population of Mouse Peritoneal Macrophages Isolated after Stimulation with Concanavalin A and Thioglycolate.

Murine peritoneal macrophages isolated from the lavage fluid after administration of thioglycolate and concanavalin A are presented by two populations of cells of different diameters. Polarization of macrophages into a proinflammatory (M1) phenotype is accompanied by an increase in number of small cells. Macrophages obtained after administration of thioglycolate demonstrate higher tendency to anti-inflammatory (M2) phenotype, while macrophages isolated after administration of concanavalin A are committed in the proinflammatory direction. Lactate level is increased in M1 macrophages in comparison with M2 cells, which indicates predominance of glycolytic metabolism. Macrophages obtained after administration of concanavalin A have reduced mitochondrial potential, which reflects a tendency to apoptosis. Autophagy activation and inhibition neutralize the differences in pro- and anti-inflammatory properties of polarized macrophages obtained after thioglycolate administration, but have less pronounced effect on macrophages obtained after administration concanavalin A. Autophagy inhibitor increases mitochondrial potential in non-polarized macrophages obtained after administration of concanavalin A. These results demonstrate divergent properties of macrophages obtained after administration of glycolate and concanavalin A due to the difference in the mechanisms of experimental peritonitis.

Hypoxia - as a Possible Regulator of the Activity of Epicardial Mesothelial Cells After Myocardial Infarction.

Aim      To study the effect of hypoxia on the activity of epithelial-mesenchymal transition (EMT) in epicardial cells, which provides formation of a specialized microenvironment.Material and methods   This study used a model of experimental myocardial infarction created by ligation of the anterior descendent coronary artery. The activity of epicardial cells after a hypoxic exposure was studied with the hypoxia marker, pimonidazole, bromodeoxyuridine, immunofluorescent staining of heart cryosections, and in vitro mesothelial cell culture.Results The undamaged heart maintained the quiescent condition of mesothelial cells and low levels of their proliferation, extracellular matrix protein production, and of the EMT activity. Acute ischemic injury induced moderate hypoxia in the epicardial/subepicardial region. This caused a global rearrangement of this region due to the initiation of EMT in cells, changes in the cell composition, and accumulation of extracellular matrix proteins. We found that the initiation of EMT in mesothelial cells may result in the formation of smooth muscle cell precursors, fibroblasts, and a population of Sca-1+ cardiac progenitor cells, which may both participate in construction of new blood vessels and serve as a mesenchymal link for the paracrine support of microenvironmental cells. In in vitro experiments, we showed that 72­h hypoxia facilitated activation of EMT regulatory genes, induced dissembling of intercellular contacts, cell uncoupling, and increased cell plasticity.Conclusion      The epicardium of an adult heart serves as a "reparative reserve" that can be reactivated by a hypoxic exposure. This creates a basis for an approach to influence the epicardium to modulate its activity for regulating reparative processes.

Transforming Growth Factor Beta (TGF-ß1) Induces Pro-Reparative Phenotypic Changes in Epicardial Cells in Mice.

We evaluated the content of active form of TGF-ß1 in the intact and post-infarction heart and the effect of this factor on the properties of epicardial cells. During the acute stage after myocardial infarction, the production of TGF-ß1 in the heart increased, which closely correlated with activation of epicardial cells (appearance of a pool of Wt1+ epicardial cells entering the epithelial-mesenchymal transition). The role of TGF-ß1 as the factor of epicardial activation was confirmed by the results of in vitro experiments: addition of recombinant TGF-ß1 to cultured epicardial cells led to enhanced expression of genes of epithelial-mesenchymal transition and phenotypic transformation of these cells leading to the appearance of cells with markers of smooth muscle cells and fibroblasts. Our findings suggest that the regulatory axis "TGF-ß1-epicardium cells" can be considered as an important link of the post-infarction reparative process and adaptive response during heart remodeling after myocardial infarction and as the target for therapeutic interventions.

Transforming Growth Factor Beta-1 (TGF-ß1) Regulates Assembly of Cardiac Spheroids.

Cells of all tissues in human body interact with their neighboring cells and components of the extracellular matrix thereby creating a unique 3D microenvironment. These interactions are realized through a complex network of biochemical and mechanical signals that are important in maintaining normal cellular homeostasis. Numerous attempts have been undertaken during the last two decades to develop 3D models for studying their properties and understanding the mechanisms of regulation of cell microenvironment in vivo. Cardiac spheroids (cardiospheres) are one these models of cardiac microenvironment. In this study we demonstrate that unique microenvironment formed in cardiospheres consists of stem/progenitor and mesenchymal cells surrounded by extracellular matrix proteins synthesized by these cells. TGF-ß1 participates in the regulation of contraction of cells forming cardiospheres, promotes activation of the epithelial-mesenchymal transition and self-organization of cells, which leads to the formation of larger spheroids. Thereby, the effect of TGF-ß1 on the cells of cardiospheres can serve as a model for studying the mechanisms of regulation of cardiac microenvironment.

[Study of the influence of etoxidol on expression of follistatin-like protein-1 (FSTL-1) in myocardium after experimental infarction in rats]. / Issledovanie vliianiia étoksidola na ékspressiiu follistatin-podobnogo belka-1 (FSTL-1) v miokarde posle éksperimental'nogo infarkta.

In heart attack, FSTL-1 is actively secreted by cardiomyocytes, accelerates growth of heart myofibrils and stimulates of vascular endothelial growth factor expression. The aim of this work was to investigate the effect of Etoxidol on synthesis of FSTL-1 in rats after myocardial infarction. The experiments were performed on Wistar rats weighing 250-350 g with simulated myocardial infarction or intact (group 5). Animals of control groups (groups 1, 2) were treated with saline for 7 and 14 days; Ethoxidol (24 mg/kg) was injected to animals of experimental groups (group 3, 4) (the daily dose was 6.36 mg/animal) for 6 or 14 days. The injection volume was 0.2 ml. At the beginning and at the end of the study plasma concentrations of FSTL-1 were determined by the ELISA method. Myocardial FSTL-1 gene expression was determined by real-time PCR. At the end of the experiments, the hearts were also used for histochemical analysis. To determine the size of the scar formed after the modeled heart attack, we used the classic Mallory staining method. The results show that the development of experimental acute myocardial infarction is accompanied by a significant increase in FSTL-1 expression in the heart, which was detected on the 7th day and stored increased by 14 days after a heart attack. After therapy with Ethoxidol, a tendency to a decrease in the expression of FSTL-1 by the 14th day was observed; it coincided with the dynamics of the plasma protein FSTL-1 level. It can be assumed that the downregulation trend in the FSTL-1 expression is associated with a more effective repair process after a heart attack, since FSTL-1 increases precisely in response to myocardial damage and decreases when the incentives for its expression from damaged heart tissue are reduced. Indirectly, this assumption is confirmed by the detected tendency to reduce the size of post-infarction fibrosis in the treatment with Ethoxidol. The results indicate the ability of Ethoxidol to influence FSTL-1 synthesis of in rats after myocardial infarction.

[Perspectives of cell therapy for myocardial infarction and heart failure based on cardiosphere cells].

Cardiovascular diseases are the leading cause of morbidity and mortality worldwide. In recent years, researchers are attracted to the use of cell therapy based on stem cell and progenitor cells, which has been a promising strategy for cardiac repair after injury. However, conducted research using intracoronary or intramyocardial transplantation of various types of stem/progenitor cells as a cell suspension showed modest efficiency. This is due to the low degree of integration and cell survival after transplantation. To overcome these limitations, the concept of the use of multicellular spheroids modeling the natural microenvironment of cells has been proposed, which allows maintaining their viability and therapeutic properties. It is of great interest to use so-called cardial spheroids (cardiospheres) spontaneously forming three-dimensional structures under low-adhesive conditions, consisting of a heterogeneous population of myocardial progenitor cells and extracellular matrix proteins. This review presents data on methods for creating cardiospheres, directed regulation of their properties and reparative potential, as well as the results of preclinical and clinical studies on their use for the treatment of heart diseases.

[Determination of the fluorescence intensity of coenzymes NADH and FAD in the skeletal muscle of the rat depending on the post-mortem interval]. / Opredelenie intensivnosti fluorestsentsii kofermentov NADN i FAD v skeletnoi myshtse krysy v zavisimosti ot davnosti nastupleniia smerti.

Aim of the study is to identify patterns of variations of the fluorescence intensity of NADH (reduced nicotinamide adenine dinucleotide) and FAD (oxidized flavin adenine dinucleotide) in the skeletal muscle depending on the time since death. For the evaluation of fluorescence intensity of the studied coenzymes, laser-induced spectroscopy in situ was used. We revealed the dynamic of the fluorescence intensity of NADH and FAD in the skeletal muscle of a rat at different times during the post-mortem period, and theoretically justified the observed phenomena. The results obtained allow us to consider the studied indicators as a potential criterion for determining the post-mortem interval.

Urokinase Receptor Regulates Adhesion of Progenitor Cardiac Cells to Vitronectin.

Vitronectin, extracellular matrix protein, plays an important role in embryonic development and in organ and tissue reparation. A unique characteristic of vitronectin is specific binding of various biological molecules, including urokinase receptor (uPAR), extracellular matrix components, adhesion receptors, growth factors, thus supporting the modulation of cell behavior. Vitronectin is in fact not found in intact myocardium, while after infarction its level increases significantly, which correlates with accumulation of uPAR+ progenitor cardiac cells in the focus. The cells isolated from the heart of wild type mice are characterized by higher adhesion to vitronectin than progenitor cardiac cells from the myocardium of uPAR knockout mice. In addition, inhibition of urokinase receptor with specific antibodies on the surface of the progenitor cardiac cells of wild type mice leads to attenuation of their adhesive activity and flattening on vitronectin matrix, which can be important for their distribution in the postinfarction myocardium and realization of the reparative functions.

Combination of Mesenchymal Stromal Cells and Cardiac Stem Cells in a Multilayer Cell Construct Promotes Activation of Notch Signaling and Initiation of Endothelial Differentiation.

We showed the possibility of generating combined tissue-engineered cell consisting of layers of rat cardiac stem cells and mesenchymal stromal cells from the adipose tissue. Cell-cell interaction within the cell sheet promoted proliferation of cardiac stem cells, expression of endothelial differentiation marker ETS1, and Notch signaling activation. The obtained results provide new insights into possible mechanisms of stimulation of endogenous regeneration processes after myocardial damage and demonstrate potential of cell-based cardiomyoplasty with the use of these combined cell sheets.

Increased expression of uPA, uPAR, and PAI-1 in psoriatic skin and in basal cell carcinomas.

There is substantial evidence implicating the urokinase system in tissue remodeling during neo-vascularization, inflammation, tumor invasion, and metastasis. Regulated degradation of the extracellular matrix at the leading edge of migrating cells, mediated by uPA and uPAR, is required for tissue remodeling, invasiveness, and angiogenesis. Psoriasis and basal cell carcinoma (BCC) are the most common skin diseases. Pathogenesis of both of them is associated with keratinocyte hyperproliferation, inflammatory cell migration, and angiogenesis-processes in which the plasminogen system (uPA, uPAR, tPA, and PAI-1) plays a crucial role. In the present study, the comparative analysis of uPA, uPAR, tPA, and PAI-1 expression in the normal skin, in the biopsies of patients with psoriasis vulgaris, and BCC was carried out. uPA, uPAR, and PAI-1 expression was up-regulated in the epidermis of psoriatic skin and in tumor cells in BCC. Increased uPAR expression was detected in the derma of psoriatic lesions and in the stroma surrounding tumor cells in BCC. Increased expression of uPA in epidermal cells in psoriasis and in tumor cells in BCC suggests an important role of the uPA system for aggressively proliferating and invading cells of epidermal origin. A possible activation of the stroma, as a result of uPA-uPAR interaction between tumor cells and the surrounding stroma, is suggested.

Regulatory Effects of Urokinase on Mesenchymal Stromal Cell Migration, Proliferation, and Matrix Metalloproteinase Secretion.

We studied the effect of urokinase, its recombinant forms, and domain fragments on migration and proliferation of adipose tissue mesenchymal stromal cells (MSCs) and MMP secretion by these cells. Urokinase, but not its recombinant forms, slightly induced directed migration of MSCs. Spontaneous migration of MSCs increased under the action of urokinase or its isolated kringle domain. Migration induced by platelet-derived growth factor was inhibited by proteolytically inactive form of urokinase, the kringle domain, and blocking antibody to urokinase receptor. Urokinase, its proteolytically inactive form, and kringle domain produced no effect on MSC proliferation. In contrast to platelet-derived growth factor, all urokinase forms induced secretion of MMP-9 by MSCs.

ISOLATION AND CHARACTERIZATION OF CARDIAC PROGENITOR CELLS OBTAINING FROM MYOCARDIAL RIGHT ATRIAL APPENDAGE TISSUE.

Resident stem cells of the heart are denoted as heterogeneous population of immature cells, which reside in the myocardium and characterized by their ability to self-renewal and are multipotent differentiation capacity into cardiomyocyte-like and vascular like cells. CSCs were originally isolated directly by long enzymatic digestion of heart tissue and selection using stem cell markers. However, long exposure to enzymatic digestion and small myocardial sample size can affect the possibility of obtaining a significant amount of viable cells. To avoid these problems, we developed a method consisting of growing of the CPC in explant culture and subsequent immunomagnetic selection.

Molecular Mechanisms of Latent Inflammation in Metabolic Syndrome. Possible Role of Sirtuins and Peroxisome Proliferator-Activated Receptor Type γ.

The problem of metabolic syndrome is one of the most important in medicine today. The main hazard of metabolic syndrome is development of latent inflammation in adipose tissue, which promotes atherosclerosis, non-alcoholic fatty liver disease, myocarditis, and a number of other illnesses. Therefore, understanding of molecular mechanisms of latent inflammation in adipose tissue is very important for treatment of metabolic syndrome. Three main components that arise during hypertrophy and hyperplasia of adipocytes underlie such inflammation: endoplasmic reticulum stress, oxidative stress, and hypoxia. Each of these components mediates activation in different ways of the key factor of inflammation - NF-κB. For metabolic syndrome therapy, it is suggested to influence a number of inflammatory signaling components by activating other cell factors to suppress development of inflammation. Such potential factors are peroxisome proliferator-activated receptors type γ that suppress transcription factor NF-κB through direct contact or via kinase of a NF-κB inhibitor (IKK), and also the antiinflammatory transcription factor AP-1. Other possible targets are type 3 NAD+-dependent histone deacetylases (sirtuins). There are mutually antagonistic relationships between NF-κB and sirtuin type 1 that prevent development of inflammation in metabolic syndrome. Moreover, sirtuin type 1 inhibits the antiinflammatory transcription factor AP-1. Study of the influence of these factors on the relationship between macrophages and adipocytes, macrophages, and adipose tissue-derived stromal cells can help to understand mechanisms of signaling and development of latent inflammation in metabolic syndrome.

[Mechanism of stimulation of angiogenesis in ischemic myocardium with the help of adipose tissue stromal cells].

Stromal cells from subcutaneous adipose tissue (adipose derived stromal cells - ASCs) are perspective for cell therapy of ischemic states because of ability to stimulate growth of vessels. For the elucidation of mechanisms of angiogenic action of ASCs we used the model of co-cultivation of ASCs with cells isolated from postnatal hearts (fraction of cardiomyocutes - CMC). CMC fraction contained mature cardiomyocytes, endothelial and progenitor cells. On the 2-nd day spontaneously beating colonies of CMC with growing from them CD31-positive capillary-like structures were formed in CMC culture. Observed structures were unstable and came apart after 5 days of cultivation. At co-cultivation of CMC with ASCs formation of stable ramified CD31-positive structures was observed. Using the method of co-cultivation of CMC with mitomycin C treated ASCs and the method of immune magnetic depletion for removal of epithelial cells from the CMC fraction we found that ASCs stimulates formation of capillary like structure at the account of secretion of angiogenic factors, stabilization of forming CD31-positive structures at the account of intercellular contacts and stimulation of endothelial differentiation of progenitor cells present in CMC fraction.

[Left ventricular heart aneurism--a new source of resident cardiac stem cells].

In the past few years it has been established that the heart contains a reservoir of stem and progenitor cells that have the ability to differentiate in vitro and in vivo toward vascular and cardiac lineages and that show cardiac regeneration potential in vivo following injection into the infracted myocardium. The aim of the present study was to characterize cardiac stem cells in the tissue of chronic left ventricular aneurism. It was shown that human c-kit positive cells were scattered in fibrous, muscle and adipose parts of aneurism tissue. C-kit positive cells localized mainly in fibrous tissue nearby large vessels, however, c-kit positive cells did not express endothelial, smooth muscle or cardiomyocyte cell markers. Co-localization experiments demonstrated that all c-kit positive cells were of non-hematopoietic origin, since they did not express markers such as CD34 and CD45. Majority of c-kit positive cells expressed MDR1, but showed no proliferation activity (Ki67). It thus appears that aneurism tissue could be an alternative source of autologous cardiac stem cells. However, their regeneration capacity should be further explored.

[The effect of hypoxia on the urokinase and adenylate cyclase systems in the culture of endothelial cells of the human umbilical vein].

Hypoxia induces angiogenesis in ischemized tissues by means of pro-angiogenic factor expression. The key role in the growth processes and blood vessel functioning belongs to the matrix metalloproteinases, plasminogen, and its activator systems. Effect of hypoxia on expression of the urokinase activating agent plasminogen and its receptor in endothelium was studied in human umbilical vein endothelial cell model. Incubation of the endothelial cells under the conditions of hypoxia proved to reduce both urokinase formation in these cells and its secreting into the culture medium. The hypoxia-induced reduction of urokinase contents was accompanied by enhancement of expression of the urokinase receptor. The hypoxia also entailed reduction of the adenylate cyclase activity and cAMP contents in the endothelial cells. The data obtained suggest that reduction of the adenylate cyclase activity and cAMP contents under the conditions of hypoxia provide basis for suppression of the urokinase expression by the endothelial cells and, consequently, inhibition of blood vessel formation in the ischemized tissue.

[Expression of urokinase plasminogen activator, its receptor and plasminogen activator inhibitor type 1 in different types of atherosclerotic lesion in human aorta]. / Ekspressiia urokinazy, ee retseptora i ingibitora aktivatorov plazminogena 1-go tipa v stenke aorty cheloveka pri raznykh tipakh ateroskleroticheskogo porazheniia.

The role of plasminogen activators in the regulation of key processes of atherosclerosis progression stays unclear. The aim of this study was to evaluate the expression of urokinase plasminogen activator (uPA), its receptor (uPAR) and the plasminogen activator inhibitor type 1 (PAI-1) in human aorta, and to balance them with the stage of atherosclerotic lesion. We have shown that uPA and uPAR in normal aorta are mostly expressed by intimal smooth muscle cells. The expression of these proteins was up-regulated in diseased aorta compared to normal artery. The most part of cells in both fatty streak and fibro-fatty lesion were monocytes/macrophages, and about 60% of these cells expressed uPA and its receptor. PAI-1 was mostly localized on the lumonal part of the aorta and in the extracellular matrix of the intima. We observed a moderate increase of PAI-1 expression in atherosclerotic lesion. Thus, our data indicate participation of plasminogen system in atherogenesis.