Biochemical Regulation of Regenerative Processes by Growth Factors and Cytokines: Basic Mechanisms and Relevance for Regenerative Medicine.

Regenerative medicine that had emerged as a scientific and medical discipline at end of 20th century uses cultured cells and tissue-engineered structures for transplantation into human body to restore lost or damaged organs. However, practical achievements in this field are far from the promising results obtained in laboratory experiments. Searching for new directions has made apparent that successful solution of practical problems is impossible without understanding the fundamental principles of the regulation of development, renewal, and regeneration of human tissues. These aspects have been extensively investigated by cell biologists, physiologists, and biochemists working in a specific research area often referred to as regenerative biology. It is known that during regeneration, growth factors, cytokines, and hormones act beyond the regulation of individual cell functions, but rather activate specific receptor systems and control pivotal tissue repair processes, including cell proliferation and differentiation. These events require numerous coordinated stimuli and, therefore, are practically irreproducible using single proteins or low-molecular-weight compounds, i.e., cannot be directed by applying classical pharmacological approaches. Our review summarizes current concepts on the regulatory mechanisms of renewal and regeneration of human tissues with special attention to certain general biological and evolutionary aspects. We focus on the biochemical regulatory mechanisms of regeneration, in particular, the role of growth factors and cytokines and their receptor systems. In a separate section, we discussed practical approaches for activating regeneration using small molecules and stem cell secretome containing a broad repertoire of growth factors, cytokines, peptides, and extracellular vesicles.

[The Involvement of Cardiomyocyte-Specific Transcription Factors Meis in Adipocyte Differentiation].

Homeodomain transcription factors play a significant role in adipocyte differentiation. The role of Pbx1 and Prep1, proteins of the TALE family (the three amino acid loop extension), was previously established in adipocyte differentiation of mesenchymal stromal cells and 3T3-L1 cell line. In this study, with the use of RNA interference technology we show that another transcription factor from the same family, Meis1, which is a core protein of mature cardiomyocytes, represses adipogenesis to a greater degree than its paralog Meis2. A number of Meis target genes, markers of adipocytes, are identified. This may indicate the transcriptional mechanism of the effect of Meis1 on the adipocyte differentiation of mouse preadipocytes.

[Fibrinolytics: from the thrombolysis to the processes of blood vessels growth and remodeling, neurogenesis, carcinogenesis and fibrosis].

One of the most outstanding scientific achievements in the thrombolysis is the development and administration of fibrinolysin - the first Soviet drug that lyses blood clots. Intracoronary administration of fibrinolysin reduced the mortality of patients with myocardial infarction by almost 20%. For his work in this field Yevgeny Chazov was awarded the Lenin Prize in 1982. Over the next decades, under his leadership, the Cardiology Center established scientific and clinical laboratories that created new generations of drugs based on fibrinolytics for treating patients with myocardial infarction, restoration of blood flow in ischemic tissue, and also studying the mechanisms of remodeling of blood vessels involving the fibrinolysis system. It have been found new mechanisms of regulation of the navigation of blood vessels and nerves growth, tumor growth and its metastasis with the participation of the fibrinolysis system proteins. The review reports the role of the fibrinolysis system in the thrombolysis, blood vessels growth and remodeling, neurogenesis, carcinogenesis and fibrosis. The article is dedicated to the 90th anniversary of academician E.I. Chazov.

Prediction of features of the course of chronic hepatitis C using Bayesian networks.

MATERIALS AND METHODS: 253 patients with chronic hepatitis C (CHC) and liver cirrhosis were included in the study. Assessment of gene polymorphisms of genes involved in inflammatory reactions and antiviral immunity (IL-1ß-511C/T, IL-10 -1082G/A, IL28B C/T, IL28B T/G, TNF-α -238G/A, TGF-ß -915G/C, IL-6 -174G/C), activators of local hepatic fibrosis (AGT G-6A, AGT 235 M/T, ATR1 1166 A/C), hemochromatosis (HFE C282Y, HFE H63D), platelet receptors (ITGA2 807 C/T, ITGB3 1565 T/C), coagulation proteins and endothelial dysfunction (FII 20210 G/A, FV 1691G/A, FVII 10976 G/A, FXIII 103 G/T, eNOS 894 G/T, CYBA 242 C/T, FBG -455 G/A, PAI-675 5G/4G, MTHFR 677 C/T) was carried. Using Bayesian networks we studied the predictor value of clinical and laboratory factors for the following conditions - end points (EP): development of cirrhosis (EP1), fibrosis rate (EP2), presence of portal hypertension (EP3) and cryoglobulins (EP4). RESULTS AND DISCUSSION: In addition to traditional factors we have shown the contribution of the following mutations. Predicting EP1- liver cirrhosis - HFE H63D, C282Y, CYBA 242 C/T, AGT G-6G, ITGB31565 T/C gene mutations were significant. We also found a link between the rate of progression of liver fibrosis and gene polymorphisms of AGT G-6G, AGT M235T, FV 1691G/A, ITGB31565 T/C. Among the genetic factors associated with portal hypertension there are gene polymorphisms of PAI-I-675 5G/4G, FII 20210 G/A, CYBA 242 C/T, HFE H63D and Il-6 174GC. Cryoglobulins and cryoglobuliemic vasculitis (EP4) are associated with gene mutations MTHFR C677T, ATR A1166C and HFE H63D. CONCLUSION: The results obtained allow to detect the major pathophysiological and genetic factors which determine the status of the patient and the outcome of the disease, to clarify their contribution, and to reveal the significance of point mutations of genes that control the main routes of HCV course and progression.

Practical Recommendations for Improving Efficiency and Accuracy of the CRISPR/Cas9 Genome Editing System.

CRISPR/Cas9 genome-editing system is a powerful, fairly accurate, and efficient tool for modifying genomic DNA. Despite obvious advantages, it is not devoid of certain drawbacks, such as propensity for introduction of additional nonspecific DNA breaks, insufficient activity against aneuploid genomes, and relative difficulty in delivering its components to cells. In this review, we focus on the difficulties that can limit the use of CRISPR/Cas9 and suggest a number of practical recommendations and information sources that will make it easier for the beginners to work with this outstanding technological achievement of the XXI century.

[The Role of Macrophages in Repair of Injured Myocardium and Perspectives of Metabolic Reprogramming of Immune Cells for Myocardial Post-Infarction Recovery].

A new trend in modern experimental cardiology is the development of approaches to correction of reparation after myocardial infarction (MI) with the use of specific effects on immune cells. One of the main targets for such interventions is the process of macrophage's polarization in the infarction zone. Proinflammatory M1­macrophages contribute to hampered myocardial repair, in contrast to M2­macrophages that promote regeneration. Currently, there are two main ways of targeted delivery of agents necessary for macrophage reprogramming - inlipoid and inglycan-encapsulated particles. As modulating agents, small interfering RNA and other genetic constructions are usually used. Both these approaches are currently awaiting their translation into cardiology. The most physiological approach to reprogramming of immune cells may consist in attempts to switch the metabolism of the immune cell from glycolytic to oxidative, which allows macrophages to switch from M1 to M2 phenotype. Among possible targets for macrophage reprogramming, it is worthwhile to isolate the protein complex mTORC1, the blocking of which promotes oxidative metabolism, and the transcription factor HIF-1α, the blocking of which also facilitates the switching of the metabolism from glycolytic to oxidative one.

Glycosylphosphatidylinositol-Anchored Proteins as Regulators of Cortical Cytoskeleton.

Glycosylphosphatidylinositol-anchored proteins (GPI-AP) are important players in reception and signal transduction, cell adhesion, guidance, formation of immune synapses, and endocytosis. At that, a particular GPI-AP can have different activities depending on a ligand. It is known that GPI-AP oligomer creates a lipid raft in its base on plasma membrane, which serves as a signaling platform for binding and activation of src-family kinases. Yet, this does not explain different activities of GPI-APs. Meanwhile, it has been shown that short-lived actomyosin complexes are bound to GPI-APs through lipid rafts. Here, we hypothesize that cell cortical cytoskeleton is the main target of GPI-AP signaling. Our hypothesis is based on the fact that the GPI-AP-induced lipid raft bound to actin filaments and anionic lipids of this raft is known to interact with and activate various actin-nucleating factors, such as formins and N-WASP. It is also known that these and other actin-regulating proteins are activated by src-family kinases directly or through their effectors, such as cortactin and abl-kinases. Regulation of cytoskeleton by GPI-APs may have impact on morphogenesis, cell guidance, and endocytosis, as well as on signaling of other receptors. To evaluate our hypothesis, we have comprehensively considered physiological activities of two GPI-APs - urokinase receptor and T-cadherin.

[Urinary bladder substitution using combined membrane based on secretions of human mesenchymal stem cells and type I collagen].

AIM: Despite the widespread use of intestinal cystoplasty, urinary bladder substitution remains a challenging problem due to the complexity of operations and the potentially high risk of complications. A promising alternative may be bio-engineered collagen-based matrices containing stem cells or their secretions. MATERIAL AND METHODS: To evaluate the effectiveness of this bladder substitution modality, an experiment was conducted on 14 male rabbits. The animals underwent resection of urinary bladder, and the formed defect was substituted with a membrane of type I collagen (series 1, 5 rabbits) or a membrane of the same composition containing a conditioned medium with secretion of mesenchymal stem/stromal cells derived from human adipose tissue (series 2, 5 rabbits). In the comparison group (4 rabbits) resection of the bladder and the closure of the defect was carried out without bladder substitution (series 3). RESULTS: At 1 month after surgery, there was a complete epithelization of the inner surface of the implant, and body tissues replaced the collagen matrix. In series 1, the collagen implant was replaced mainly by connective tissue ingrown with occasional solitary smooth muscle cells. In series 2, the newly formed bladder wall contained numerous smooth muscle cells, growing into the collagen matrix and forming the muscular coat. In series 3, the muscular layer regeneration at the scar site was also noted, but it was less intense, which was confirmed by morphometry. In series 2, more active vascularization of the collagen implant occurred due to neo-angiogenesis, which was more intense than that in series 3, and especially in series 1. Functional studies revealed a reduced bladder functional capacity in series 1 and 3, while in series 2 it was close to normal. During filling cystometry, changes in intra-vesical pressure profile in series 2 were close to normal, while in series 1 and 3 infusion of a small volume of saline resulted in a marked increase in intra-vesical pressure, showing a reduced compliance of the reconstructed bladder. Discussion The study findings show that implants based on type I collagen can be effectively used to substitute a part of the urinary bladder wall, but bio-engineered collagen matrix grafts containing cell regeneration stimulants secreted by stem cells in their culture medium seem to be more promising.

Guidance Receptors in the Nervous and Cardiovascular Systems.

Blood vessels and nervous fibers grow in parallel, for they express similar receptors for chemokine substances. Recently, much attention is being given to studying guidance receptors and their ligands besides the growth factors, cytokines, and chemokines necessary to form structures in the nervous and vascular systems. Such guidance molecules determine trajectory for growing axons and vessels. Guidance molecules include Ephrins and their receptors, Neuropilins and Plexins as receptors for Semaphorins, Robos as receptors for Slit-proteins, and UNC5B receptors binding Netrins. Apart from these receptors and their ligands, urokinase and its receptor (uPAR) and T-cadherin are also classified as guidance molecules. The urokinase system mediates local proteolysis at the leading edge of cells, thereby providing directed migration. T-cadherin is a repellent molecule that regulates the direction of growing axons and blood vessels. Guidance receptors also play an important role in the diseases of the nervous and cardiovascular systems.

[UROKINASE SYSTEM INVOLVES IN VASCULAR CELLS MIGRATION AND REGULATES THE GROWTH AND BRANCHING OF CAPILLARIES].

Urokinase system representing urokinase-type plasminogen activator (urokinase, uPA) and urokinase re- ceptor (uPAR) plays an important regulatory role in the vascular wall and has the ability to run a proteolytic cascade, degradation of extracellular matrix and activate intracellular signaling in vascular cells. In this work, we have firstly shown a fundamental mechanism of urokinase system-dependent regulation of the trajectory of growth and branching of blood vessels what may be of particular importance in the growth of blood vessels in early embryogenesis and in adults during the repair/regeneration of tissues.

Molecular modeling as a new approach to the development of urokinase inhibitors.

Proteolytic activity of urokinase plays an important role in negative remodeling of blood vessels, restenosis, tumor angiogenesis, and metastasizing, which necessitates the development of selective urokinase inhibitors. Using methods of computer modeling (docking, post processing, and direct docking) and quantum chemistry, we selected substances from the large compound database, analyzed their structures, and experimentally verified their inhibitor activity. New urokinase inhibitor candidates were proposed based on the theoretical predictions and experimental verification of compound activities. The process of modifying urokinase inhibitors based on (benzothiazol-3-yl)guanidine was developed. A new urokinase inhibitor (5-brom-benzothiazol-3-yl)guanidine, that can be effective for regulation of vascular remodeling and tumor angiogenesis, was created.

[Mathematic Model for Prediction of Liver Fibrosis Progression Rate in Patients with Chronic Hepatitis C Based on Combination of Genomic Markers].

AIM OF STUDY: To evaluate clinical significance of different combinations of gene polymorphisms IL-1b, IL-6, IL-10, TNF, HFE, TGF-b, ATR1, N0S3894, CYBA, AGT, MTHFR, FII, FV, FVII, FXIII, ITGA2, ITGB3, FBG, PAI and their prognostic value for prediction of liver fibrosis progression rate in patients with chronic hepatitis C (CHC). SUBJECTS AND METHODS: 118 patients with CHC were divided into "fast" and "slow" (fibrosis rate progression ≥ 0.13 and < 0.13 fibrosis units/yr; n = 64 and n = 54) fibrosis groups. Gene polymorphisms were determined. Statistical analysis was performed using Statistica 10. RESULTS: A allele (p = 0.012) and genotype AA (p = 0.024) of AGT G-6T gene, as well as T allele (p = 0.013) and MT+TT genotypes (p = 0.005) of AGT 235 M/T gene were significantly more common in "fast fibrosers" than in "slow fibrosers". Patients with genotype TT of CYBA 242 C/T had a higher fibrosis progression rate than patients with CC+CT genotype (p = 0.02). Our analysis showed a protective effect of TTgenotype of ITGA2 807 C/T on fibrosis progression rate (p = 0.03). There was a trend (p < 0.15) to higher fibrosis progression rate in patients with mutant alleles and genotypes of TGFb +915 G/C, FXIII 103 G/T, PAI-675 5G/4G genes. Other gene polymorphisms were not associated with enhanced liver fibrosis. To build a mathematical modelfor prediction of liverfibrosis progression rate we performed coding with scores for genotypes and virus genotype. Total score correlated with the fibrosis progression rate (R = 0.39, p = 0.000). CONCLUSION: Determination of genetic profile of the patient and virus genotype allows to predict the course of CHC.

[Mechanisms of Vascular Remodeling Following Arterial Injury].

Arterial remodeling is the process of adaptation of the vessel comprising multiple structural and functional alterations of the vascular wall that occur in disease, trauma or aging. Arterial remodeling is accelerated in conditions that adversely affect the structural and functional balance of the vascular system, such as hypertension, atherosclerosis, kidney disease, inflammatory diseases, genetic abnormalities, and mechanical damage. Pathological changes in the vascular wall lead to organ damage and, ultimately, death. The aim of this paper is to review the various factors and complex mechanisms, which underlie negative arterial remodeling after mechanical injury and data indicating on the key role of the urokinase plasminogen activator in this process.

[Therapeutic Angiogenesis Using Growth Factors: Current State and Prospects for Development].

Therapeutic angiogenesis has been in use for treatment of ischemic diseases for about 15 years. During this period of successes and failures this field has accumulated a significant amount of published and ongoing surveys giving insights and raising new questions and problems. One of the most utilized methods for therapeutic angiogenesis suggests introduction of angiogenic growth factors (VEGF, bFGF, angiopoietin-1 etc.) into ischemic tissues. Still, there is a whole range of problems regarding the efficacy of therapeutic angiogenesis. These can be potentially circumvented by use of new delivery methods, development of combined approaches and use of more relevant pre-clinical animal models. Present review gives a brief analysis of crucial achievements and issues that has been recently raised in experimental and clinical studies focusing on therapeutic angiogenesis. Final part brings some possible directions for development that can give an opportunity to circumvent current obstacles and provide further development.

[Single Nucleotide Polymorphisms in T-Cadherin Gene (CDH13) Have Cumulative Effect on Body Mass in Patients With Ischemic Heart Disease].

BACKGROUND: Low adiponectin concentration observed in obese patients is associated with a high risk of metabolic disorders and cardiovascular diseases and could be related to single nucleotide polymorphisms (SNPs) in T-cadherin gene (CDH13). T-cadherin is a receptor for adiponectin and low-density lipoprotein. Aim of this study was to investigate association of CDH13 SNPs with the development of obesity in patients with ischemic heart disease (IHD). RESULTS: We established a statistically significant correlation between the number of minor alleles of rs11646213, rs4783244 and rs12444338 in CDH13 gene with body mass index: patients with smaller number of minor alleles tended to have normal body weight (odds ratio 3.03, 95% confidence interval 1.03-8.87). CONCLUSION: The obtained results are indicative of the cumulative effect of SNPs in CDH13 (rs11646213, rs4783244, rs12444338) on BMI in patients with IHD.

Proteolytically inactive recombinant forms of urokinase suppress migration of endothelial cells.

Proteolytically inactive recombinant forms of urokinase (uPAHQ and amino-terminal fragment) inhibit spontaneous migration of endothelial cells; amino-terminal fragment also suppresses angiogenesis stimulated by basic fibroblast growth factor in vitro. These findings suggest the possibility of using synthesized proteolytically inactive recombinant forms of urokinase for the regulation of endothelial cell migration and suppression of neoangiogenesis.

[Endothelial dysfunction gene polymorphisms and the rate of liver fibrosis in chronic hepatitis C].

AIM: To assess the association of the CYBA, NOS3, and MTHFR gene polymorphisms and a rate of fibrosis progression in chronic hepatitis C (CHC). SUBJECTS AND METHODS: One hundred and nine CHC patients with the verified stage of liver fibrosis and cirrhosis at its onset were examined. The disease duration was determined in all the patients and additional risk factors of liver lesion were absent. A group of rapidly progressive fibrosis comprised 55 patients with a calculated fibrosis progression rate of 0.130 fibrosis units/year or higher and 54 patients with a progression rate of less than 0.130 fibrosis units/year were assigned to a slow fibrosis group. A compression group consisted of 299 healthy blood donors. The polymorphism of the genes under study was determined by polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: The mutant TT genotype of the CYBA gene was significantly more common in the CHC patients with rapidly progressive fibrosis than in those with slowly progressive fibrosis (odds ratio for TT 9.09 at 95% confidence interval, 1.09 to 74.83; p = 0.0161). No significant differences were found in the distribution of the alleles and genotypes of the NOS3 and MTHFR genes between the groups of patients with slowly and rapidly progressive fibrosis. CONCLUSION: The findings make it possible to regard the TT genotype of the CYBA gene from the C242T locus as profibrogenic and as one of the markers of the poor course of CHC.

[The secretome of mesenchymal stromal cells as a new hope in the treatment of acute brain tissue injuries]. / Sekretom mezenkhimnykh stromal'nykh kletok kak novaya nadezhda v lechenii ostrykh povrezhdenii golovnogo mozga.

Ischemic and hemorrhagic strokes, traumatic brain injury, bacterial and viral encephalitis, toxic and metabolic encephalopathies are very different pathologies. But, they have much more in common than it might seem at first glance. In this review, the authors propose to consider these brain pathologies from the point of view of the unity of their pathogenetic mechanisms and approaches to therapy. Particular attention is paid to promising therapeutic approaches, such as therapy using cells and their secretion products: an analysis of the accumulated experimental data, the advantages and limitations of these approaches in the treatment of brain damage was carried out. The review may be of interest both to specialists in the field of neurology, neurosurgery and neurorehabilitation, and to readers who want to learn more about the progress of regenerative biomedicine in the treatment of brain pathologies.

Insulin resistance and adipogenesis: role of transcription and secreted factors.

Insulin stimulates carbohydrate uptake by cells and induces their conversion into lipids as a more efficient form of energy storage. Insulin resistance is associated with a decrease in glucose uptake by muscle and adipose cells and also with a decrease in glycogen synthesis on retention of glucose synthesis by liver cells. Disorders in the insulin signaling cascade on development of insulin resistance can be caused by both changes in functioning of transcriptional factors and in the secretion profile of hormone-like substances. Diacylglycerols and ceramides responsible for activation of some kinases and phosphatases can directly trigger these changes in muscle and liver cells. In adipose tissue, insulin mainly stimulates adipogenesis (adipocyte differentiation) and lipogenesis (lipid accumulation in the cells). Thus, studies on the action mechanisms of factors influencing adipogenesis can be of help for understanding the molecular mechanisms of insulin resistance.

Structural investigations of recombinant urokinase growth factor-like domain.

Urokinase-type plasminogen activator (uPA) is a serine protease that converts the plasminogen zymogen into the enzymatically active plasmin. uPA is synthesized and secreted as the single-chain molecule (scuPA) composed of an N-terminal domain (GFD) and kringle (KD) and C-terminal proteolytic (PD) domains. Earlier, the structure of ATF (which consists of GFD and KD) was solved by NMR (A. P. Hansen et al. (1994) Biochemistry, 33, 4847-4864) and by X-ray crystallography alone and in a complex with the soluble form of the urokinase receptor (uPAR, CD87) lacking GPI (C. Barinka et al. (2006) J. Mol. Biol., 363, 482-495). According to these data, GFD contains two ß-sheet regions oriented perpendicularly to each other. The area in the GFD responsible for binding to uPAR is localized in the flexible Ω-loop, which consists of seven amino acid residues connecting two strings of antiparallel ß-sheet. It was shown by site-directed mutagenesis that shortening of the Ω-loop length by one amino acid residue leads to the inability of GFD to bind to uPAR (V. Magdolen et al. (1996) Eur. J. Biochem., 237, 743-751). Here we show that, in contrast to the above-mentioned studies, we found no sign of the ß-sheet regions in GFD in our uPA preparations either free or in a complex with uPAR. The GFD seems to be a rather flexible and unstructured domain, demonstrating in spite of its apparent flexibility highly specific interaction with uPAR both in vitro and in cell culture experiments. Circular dichroism, tryptophan fluorescence during thermal denaturation of the protein, and heteronuclear NMR spectroscopy of ¹5N/¹³C-labeled ATF both free and in complex with urokinase receptor were used to judge the secondary structure of GFD of uPA.