Desmin mutations impact the autophagy flux in C2C12 cell in mutation-specific manner.

Desmin is the main intermediate filament of striated and smooth muscle cells and plays a crucial role in maintaining the stability of muscle fiber during contraction and relaxation cycles. Being a component of Z-disk area, desmin integrates autophagic pathways, and the disturbance of Z-disk proteins' structure negatively affects chaperone-assisted selective autophagy (CASA). In the present study, we focused on alteration of autophagy flux in myoblasts expressing various Des mutations. We applied Western blotting, immunocytochemistry, RNA sequencing, and shRNA approach to demonstrate that DesS12F, DesA357P, DesL345P, DesL370P, and DesD399Y mutations. Mutation-specific effect on autophagy flux being most severe in aggregate-prone Des mutations such as DesL345P, DesL370P, and DesD399Y. RNA sequencing data confirmed the most prominent effect of these mutations on expression profile and, in particular, on autophagy-related genes. To verify CASA contribution to desmin aggregate formation, we suppressed CASA by knocking down Bag3 and demonstrated that it promoted aggregate formation and lead to downregulation of Vdac2 and Vps4a and upregulation of Lamp, Pink1, and Prkn. In conclusion, Des mutations showed a mutation-specific effect on autophagy flux in C2C12 cells with either a predominant impact on autophagosome maturation or on degradation and recycling processes. Aggregate-prone desmin mutations lead to the activation of basal autophagy level while suppressing the CASA pathway by knocking down Bag3 can promote desmin aggregate formation.

[Practical guidelines for the diagnosis and treatment of transthyretin amyloid cardiomyopathy (ATTR-CM or transthyretin cardiac amyloidosis)].

This paper summarizes the data from updated international protocols and guidelines for diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM). The invasive and non-invasive diagnosis techniques and their combinations are briefly reviewed; the evidentiary foundations for each diagnostic option and tool are analyzed. The paper describes a customized algorithm for sequential diagnosis and differential diagnosis of patients with suspected ATTR-CM with allowance for the combination of clinical signs and diagnostic findings. Along with the awareness of primary care providers about the red flags of the disease and visualization criteria, as well as providing information to the patients about the possibility of performing therapy of ATTR amyloidosis and the risks of delayed diagnosis, the proposed algorithm enables timely patient routing and prescribing specific treatment.

[AL-amyloidosis with cardiac involvement. Diagnostic capabilities of non-invasive methods].

There are presented the literature data and a description of the clinical course of the disease in isolated/predominant cardiac amyloidosis. Amyloid cardiomyopathy is the most common phenocopy of hypertrophic cardiomyopathy. The modern possibilities of non-invasive diagnostics using osteoscintigraphy for the differential diagnosis between amyloid cardiomyopathy caused by AL- and transthyretin amyloidosis are described in detail.

R482L Mutation of the LMNA Gene Affects Dynamics of C2C12 Myogenic Differentiation and Stimulates Formation of Intramuscular Lipid Droplets.

Mutations in the LMNA gene resulting in the substitution of the highly conserved arginine 482 residue in the globular C-terminal domain of lamin A/C are associated with the Dunnigan-type familial partial lipodystrophy (FPLD2) often accompanied by impairments in the muscle tissue development. The mechanisms underlying these impairments remain unknown. The purpose of our work was to investigate the effects of the LMNA gene mutation R482L on the muscle differentiation and intramuscular fat accumulation using C2C12 mouse myoblasts transduced with the lentiviral constructs carrying the wild-type human LMNA gene (LMNA-WT) or the LMNA-R482L mutant gene. After stimulation of myogenesis and adipogenesis in the transduced cell, expression of muscle and adipose tissue differentiation markers, morphology of differentiated myotubes, and formation of intramuscular lipid droplets were analyzed. C2C12 cells carrying the LMNA-R482L construct exhibited upregulated desmin expression at all stages of muscle differentiation and transformed into hypertrophied myotubules (in comparison with C2C12 myoblasts transduced with LMNA-WT). Reduced expression levels of the myogenic transcription factor Myf6 in the cells with the LMNA-R482L mutant indicated delayed maturation of muscle fibers. These cells more actively accumulated fat in response to the stimulation of adipose differentiation than myoblasts modified with the wild-type LMNA; they also expressed the markers of lipid droplets, such as FABP4 (fatty acid-binding protein 4), ATGL (adipose triglyceride lipase), and PLIN2 (perilipin 2). Therefore, the R482L mutation of the LMNA gene affects the dynamics of C2C12 myoblast differentiation into myotubules and stimulates formation of fat deposits in the myoblasts and myotubules in a tissue-specific manner.

Extracellular MicroRNAs and Mitochondrial DNA as Potential Biomarkers of Arrhythmogenic Cardiomyopathy.

Differential diagnosis of arrhythmogenic cardiomyopathy (ACM) during the disease latent phase is a challenging clinical problem that requires identification of early ACM biomarkers. Because extracellular nucleic acids are stable, specific, and can be easily detected, they can be used as reliable biomarkers of various diseases. In this study, we analyzed the levels of extracellular microRNAs and mitochondrial DNA in the conditioned medium collected from cardiomyocytes differentiated from induced pluripotent stem cells of ACM patients and healthy donor. Several microRNAs were expressed differently by the affected and healthy cardiomyocytes; therefore, they could be considered as potential ACM biomarkers.

Skeletal Muscle Resident Progenitor Cells Coexpress Mesenchymal and Myogenic Markers and Are Not Affected by Chronic Heart Failure-Induced Dysregulations.

BACKGROUND AND PURPOSE: In heart failure (HF), metabolic alterations induce skeletal muscle wasting and decrease of exercise capacity and quality of life. The activation of skeletal muscle regeneration potential is a prospective strategy to reduce muscle wasting; therefore, the aim of this project was to determine if functional properties of skeletal muscle mesenchymal progenitor cells (SM-MPC) were affected by HF-induced functional and metabolic dysregulations. METHODS: Gastrocnemius muscle biopsy samples were obtained from 3 healthy donors (HD) and 12 HF patients to purify mRNA for further analysis and to isolate SM-MPC. Cells were expanded in vitro and characterized by immunocytochemistry and flow cytometry for expression of mesenchymal (CD105/CD73/CD166/CD146/CD140b/CD140a/VIM) and myogenic (Myf5/CD56/MyoG) markers. Cells were induced to differentiate and were then analyzed by immunostaining and Q-PCR to verify the efficiency of differentiation. The expression of genes that control muscle metabolism and development was compared for HD/HF patients in both muscle biopsy and in vitro-differentiated myotubes. RESULTS: The upregulation of MYH3/MYH8/Myf6 detected in HF skeletal muscle along with metabolic alterations indicates chronic pathological activation of the muscle developmental program. SM-MPC isolated from HD and HF patients represented a mixed population that coexpresses both mesenchymal and myogenic markers and differs from AD-MMSC, BM-MMSC, and IMF-MSC. The functional properties of SM-MPC did not differ between HD and HF patients. CONCLUSION: In the present work, we demonstrate that the metabolic and functional alterations we detected in skeletal muscle from HF patients do not dramatically affect the functional properties of purified and expanded in vitro SM-MPC. We speculate that skeletal muscle progenitor cells are protected by their niche and under beneficial circumstances could contribute to muscle restoration and prevention and treatment of muscle wasting. The potential new therapeutic strategies of HF-induced skeletal muscle wasting should be targeted on both activation of SM-MPC regeneration potential and improvement of skeletal muscle metabolic status to provide a favorable environment for SM-MPC-driven muscle restoration.

[Left ventricular non - compaction: contemporary view of genetic background, clinical course, diagnostic and treatment].

This review highlights and discusses recent advances in understanding left ventricular non - compaction (LVNC). Clinical profile, prognosis and even diagnosis are still a great challenge faced by the world. The population prevalence of left ventricular non - compaction remains unknown. High variability of clinical manifestations, genetic heterogenity with overlap of different phenotypes, variability of hereditary patterns suggests that LVNC seems to be rather an isolated trait or a part of phenotypic expression of different cardiac diseases or complex genetic syndromes.

[Hypertrophic cardiomyopathy: modern aspects of pharmacologic treatment].

This article discusses recent advances in understanding genetic basis and classification of hypertrophic cardiomyopathy. Here, we review pharmacologic treatment strategies and new developments in disease - specific management of HCM.

Cellular Mechanisms of Aortic Valve Calcification.

Comparative in vitro study examined the osteogenic potential of interstitial cells of aortic valve obtained from the patients with aortic stenosis and from control recipients of orthotopic heart transplantation with intact aortic valve. The osteogenic inductors augmented mineralization of aortic valve interstitial cells (AVIC) in patients with aortic stenosis in comparison with the control level. Native AVIC culture of aortic stenosis patients demonstrated overexpression of osteopontin gene (OPN) and underexpression of osteoprotegerin gene (OPG) in comparison with control levels. In both groups, AVIC differentiation was associated with overexpression of RUNX2 and SPRY1 genes. In AVIC of aortic stenosis patients, expression of BMP2 gene was significantly greater than the control level. The study revealed an enhanced sensitivity of AVIC to osteogenic inductors in aortic stenosis patients, which indicates probable implication of OPN, OPG, and BMP2 genes in pathogenesis of aortic valve calcification.

EXTRACELLULAR VESICLES FROM BLOOD PLASMA STUDIED BY LOW VOLTAGE SCANNING ELECTRON MICROSCOPY.

Extracellular vesicles are subspherical membranous structures secreted by cells and enriched with different types of biological molecules. The number and the molecular content of these structures depend on pathological conditions and the physiological state of the organism. Extracellular vesicles play an important role in intercellular communication and represent potential disease biomarkers. However, mechanisms of formation, functions and morphological characteristics of extracellular vesicles are still studied insufficiently. Low voltage scanning electron microscopy is a promising method to investigate extracellular vesicles, since it does not require conductive coating and therefore enables a high-resolution visualization of morphological details of nanosized objects. This paper presents the results of low voltage scanning electron microscopy study of morphology and size of objects from blood plasma fractions.

THE ROLE OF LMNA MUTATIONS IN MYOGENIC DIFFERENTIATION OF PRIMARY SATELLITE CELLS AND C2C12 CELLS.

Nuclear lamins form nuclear lamina localized under the inner nuclear membrane. It was previously considered that the nuclear lamina predominantly plays a structural role, however, its involvement have been recently described in the regulatory processes such as chromatin organization and gene transcription. It is known that mutations in the LMNA gene lead to the development of a large number of diseases, laminopathies, which mainly affect mesenchymal tissue. Nowadays, the mechanisms by which the lamina can regulate cell differentiation remain incompletely understood. In the present work, we have studied the effect of LMNA gene mutations on the process of muscle differentiation of primary satellite cells and Ñ2Ñ12 cell line. The genome of satellite cells and Ñ2Ñ12 cell line was modified by the introduction of lentiviral constructs encoding LMNA G232E associated with the development of muscular dystrophy Emery­Dreyfus and LMNA R571S associated with the development of dilated cardiomyopathy. The morphology of the cells was estimated using immunofluorescence, the expression level of myogenic genes were analyzed by qPCR. We have shown that the analyzed mutations reduce the ability of cells to differentiate, to fuse and to form myotubes. We have suggested that it is due to enhanced expression of markers at the early stages and to reduced expression markers at the late stages of myogenesis. Therefore, mutations in nuclear lamins can influence the process of muscle differentiation.

[Possibilities of cryopreservation of ovarian tissue for fertility preservation in cancer patients].

One of the effective methods of fertility preservation is an autologous transplantation of cryopreserved ovarian tissue. Currently, according to the world literature, after orthotopic autotransplantation of ovarian tissue 37 healthy children were born. In 2014 at the North-West Federal Medical Research Center it was established Cryobank of ovarian tissue, which is now kept 50 samples of ovarian tissue of man. Cryoconservation is performed by standard slow freezing. Autotransplantation of cryopreserved ovarian tissue has unique advantages over other methods of fertility preservation. This method does not lead to the postponement of anticancer therapy, safe for hormone-dependent cancer and can be performed regardless of the day of menstrual cycle and it is the only option for fertility preservation in prepubertal girls. The use of this method in clinical practice leads to restoration of endocrine function of the ovaries as well as of fertility in the future.

[PROTEIN KINASE C EXPRESSION FOLLOWING REMOTE ISCHEMIC PRECONDITIONING IN CARDIAC SURGERY].

OBJECTIVE: To evaluate cardioprotective effects of remote ischemic preconditioning (RIPC) in cardiac surgery patients undergoing aortic valve replacement depending on the type of anesthesia and investigate the level of myocardial protein kinase C epsilon (PKC-ε) expression after RIPC. METHODS: In prospective randomized trial, forty eight patients aging from 50 to 75 years old (64 (56 ;69)) were included All patients were scheduled for aortic valve replacement using cardiopulmonary bypass (CPB). The patients were randomized into 4 groups: 1) RIPC applied during propofol anesthesia (RIPC prop, n = 12), 2) RIPC applied during sevoflurane anesthesia (RIPC sev, n = 12), 3) propofol anesthesia without RIPC (CONTROL prop, n = 12), 4) sevoflurane anesthesia without RIPC (CONTROL sev, n = 12). There was no difference found between the groups as to the baseline patient's data. RIPC protocol consisted of 3 simultaneous ischemic episodes of both lower limbs (5 minutes) with 5-min reperfusion intervals. PKC-ε expression in right atrial myocardium was assessed using Western blotting. Troponin I (cTnI) was estimated before anesthesia induction, after 30 min, 6, 12, 24, 48 hours after CPB completion. Also we calculated area under curve of cTnI (cTnI AUC). According to nonparametric distribution, data were assessed by the Mann-Whitney U-test and Newman-Keuls methodfor multigroup comparison. p < 0.05 was considered signifcant. The data are presented as median (25th; 75th percentile). RESULTS: Cardioprotective effects of RIPC were observed only after sevoflurane anesthesia: cTnI AUC was 134,8 (122,3; 232.4) ng/ml/48 h in CONTROL sev group and only 74.3 (64.7; 85.0) ng/ml/48 h in RIPC sev group (p < 0.05). RIPC applied during propofol anesthesia was not associated with cTnIAUC decrease: 93.8 (74.1; 246.8) ng/ml/48 h in CONTROL prop group and 122.5 (74.1; 185.0) ng/ml/48 h in RIPC prop group (p = 0.37). RIPC applied during sevoflurane anesthesia significantly increased PKC-ε expression: 1221 (921; 1438) U in CONTROL sev group vs 1882 (1564; 2131) U in RIPC sev group 6 (p < 0.05). RIPC implication during propofol anesthesia was not associated with any significant difference in PKC-ε expression in comparison with control group: 620 (436; 782) U in CONTROL prop group versus 788 (574;1063) U in RIPC prop group. In control groups, PKC-ε expression was significantly higher in sevoflurane anesthesia in comparison with propofol anesthesia. CONCLUSION: RIPC was only effective when it was applied during sevofiurane anesthesia. This was confirmed by PKC-ε expression increase and lower value of cTnI. There were no evidence of preconditioning and cardioprotection when MPG was initiated during propofol anesthesia.

[THE EFFECT OF PLAKOPHILIN-2 GENE MUTATIONS ON ACTIVITY OF THE CANONICAL Wnt SIGNALING PATHWAY].

Plakophilin-2 is a desmosomal protein encoded by PKP2 gene. Desmosomal proteins are usually considered as structural proteins with the main function of maintaining intercellular interactions. Genetic studies revealed that mutations in desmosomal genes could lead to arrhythmogenic right ventricular cardiomyopathy, heart disease characterized by substitution of cardiomyocytes by adipose and fibrotic tissue predominantly in right ventricle. Wnt signaling pathway is one of the signal transduction pathways which could be involved in the formation of the pathology. The purpose of this study was to investigate Wnt activity changes caused by PKP2 mutations during adipogenic and cardiomyogenic differentiation. We used multipotent mesenchymal stromal cells and iPS cells generated from patient carrying PKP2 gene mutation. We show that Wnt activity is lower in the cells with mutant PKP2. This data indicate a possible signaling role of plakophilin-2 by regulating Wnt activity.

[Nuclear lamins regulate osteogenic differentiation of mesenchymal stem cells].

Nuclear lamins are the major proteins of nuclear envelope and provide the strength of nuclear membrane as well as the interaction of extra-nuclear structures with components of cell nucleus. Recently, it became clear that lamins not only play a structural role in the cell, but could also regulate cell fate, for example lamins could influence cell differentiation via interaction with components of the Notch signaling pathway. Human mutations in LMNA, encoding lamin A/C lead to diseases commonly referred to as laminopathies. Different mutations cause tissue specific phenotypes that affect predominantly a tissue of mesenchymal origin. The nature of this phenomenon, as well as the mechanisms by which lamins regulate cell differentiation remain poorly understood. The aim of this study was to investigate the effect of different mutations of the LMNA on human mesenchymal stem cell (MSC) osteogenic differentiation, and to explore a possible interaction of lamins and Notch signaling pathway. We modified human MSC with mutant LMNA bearing known mutations with tissue specific phenotype associated with different laminopathies. We have shown that mutations associated with different diseases have different effects on the efficiency of MSC osteogenic differentiation and on the expression of specific osteogenic markers SPP1, IBSP and BGLAP. We have also shown that one of the mechanisms involved in the regulation of MSC differentiation may be an interaction of lamins A/C with components of Notch signaling.

[Comparative assessment of different approaches for obtaining terminally differentiated muscle cells].

Relevant cell model is essential to study pathogenesis of muscle disorders. However, in the field of muscle research there is no ultimate cell line considered as a standard for studying muscular and neuromuscular diseases. Standard cell line claimed to be well differentiated in muscle lineage, be morphological and physiological similar to mature muscle cells and be easily genetically modified. Therefore, the goal of our study was to pick up available and fruitful cell model of muscle differentiation, that could be further applied for examination of muscular disorder pathogenesis in vitro. We characterized human mesenchymal stem cells (MSC), mature murine muscle fibers and primary murine satellite cells. It has been shown that MSC have very small capacity to myogenic differentiation; moreover, they were able to differentiate only in presence of C2C12 cells. Lentiviral transduction exhibited rather high toxic effect on primary myofibers, and positively transduced cells were not able to response to electrical stimulation, i. e. were functionally inactive. Satellite cells turned out to be the most fruitful cell model since they were easily transduced via lentiviruses and rapidly formed myotubes in differentiation media. Functional analysis of obtained myotubes has confirmed their ability to react to electrical and chemical stimulations; besides, potassium and calcium channels availability has been also demonstrated via patch-clump technique. Taken together, these results imply that satellite cells are the most promising cell line for further experiments aimed at exploring the molecular pathways of muscle pathologies.

Synthesis of some CC chemokines and their receptors in the synovium in rheumatoid arthritis.

We studied the expression of some CC chemokines and their receptors in the synovium of patients with rheumatoid arthritis, osteoarthrosis, and a history of joint injury. In patients with rheumatoid arthritis, the levels mRNA for some angiogenic and proinflammatory chemokines (CCL5/RANTES, CCL11/eotaxin, CCL24/eotaxin-2, and CCL26/eotaxin-3) and their receptors (CCR1, CCR2, CCR3, CCR4, and CCR5) was elevated. mRNA expression correlated with activity, stage, and serological status of rheumatoid arthritis. Obtained data confirm the importance of CC chemokines as mediators of angiogenesis and inflammation in the synovium in rheumatoid arthritis.

Polymorphisms of ß 1-adrenoreceptor gene and cardiovascular complications in patients with thyrotoxicosis.

Human cardiac ß 1-AR perform a crucial role in mediating the cardiostimulating effects of norepinephrine. Gly389Arg and Ser49Gly polymorphisms of ß 1-adrenoreceptors ( ß 1-AR) can influence the cardiovascular prognosis. However, the possible effect of Gly389Arg and Ser49Gly polymorphisms on heart function in thyrotoxicosis has not been studied. We investigated the possible link between Gly389Arg and Ser49Gly polymorphisms and echocardiography parameters in 165 normotensive patients with a thyrotoxicosis without any cardiovascular disorders. Echo-CG was performed according to standard protocol before and during the thyreostatic treatment. Our data demonstrate that both Gly389Arg and Ser49Gly polymorphisms have very moderate influence on the risk of left ventricular hypertrophy and atrial fibrillation with no statistically significant effects on cardiac function and the development of cardiovascular complications.

[Functional properties of smooth muscle cells in ascending aortic aneurysm].

Thoracic aortic aneurism (TAA) develops as a result of complex series of events that dynamically alter the structure and composition of the aortic vascular extracellular matrix (ECM). The main elements that alter the composition of aortic wall are smooth muscle cells (SMC). The purpose of the present work was to study alteration of smooth muscle cell functions derived from the patients with TAA and from healthy donors. As it is supposed that TAA associated with bicuspid aortic valve (BAV) and with tricuspid aortic valve (TAV) differ in their pathogenesis, we compared the SMC and tissues samples from BAV-, TAV-patients and healthy donors. We compared TAA patients' derived tissues and SMC to healthy donors' ones in several parameters: SMC growth, migration and apoptotic dynamics; metalloproteinase MMP2 and MMP9 activity (zymography) and elastin, collagen and fibrillin content (Western blot) in both tissue samples and cultured SMC. Proliferation ability of both BAV and TAV SMC was decreased comparing to donors cells; migration ability in scratch tests was increased in TAV-derived SMC comparing to donor cells. BAV-cells migration ability was not changed comparing to donor-SMC. Elastin content was decreased in TAA SMC comparing to donor cells whereas the content of fibrillin and collagen was not altered. At the same time elastin and collagen protein level was significantly higher in tissue samples of TAA patients comparing to donor-derived samples. SMS proliferation and migration ability is differently affected in TAV and BAV-associated TAA that supports the idea of different nature of these two groups of TAA. Also our data show that SMC functional properties are altered in TAA patients and these alterations could play a significant role in the disease pathogenesis.