Identification of ATM-dependent long non-coding RNAs induced in response to DNA damage.

DNA damage response (DDR) is a complex process, essential for cell survival. Especially deleterious type of DNA damage are DNA double-strand breaks (DSB), which can lead to genomic instability and malignant transformation if not repaired correctly. The central player in DSB detection and repair is the ATM kinase which orchestrates the action of several downstream factors. Recent studies have suggested that long non-coding RNAs (lncRNAs) are involved in DDR. Here, we aimed to identify lncRNAs induced upon DNA damage in an ATM-dependent manner. DNA damage was induced by ionizing radiation (IR) in immortalized lymphoblastoid cell lines derived from 4 patients with ataxia-telangiectasia (AT) and 4 healthy donors. RNA-seq revealed 10 lncRNAs significantly induced 1 h after IR in healthy donors, whereas none in AT patients. 149 lncRNAs were induced 8 h after IR in the control group, while only three in AT patients. Among IR-induced mRNAs, we found several genes with well-known functions in DDR. Gene Set Enrichment Analysis and Gene Ontology revealed delayed induction of key DDR pathways in AT patients compared to controls. The induction and dynamics of selected 9 lncRNAs were confirmed by RT-qPCR. Moreover, using a specific ATM inhibitor we proved that the induction of those lncRNAs is dependent on ATM. Some of the detected lncRNA genes are localized next to protein-coding genes involved in DDR. We observed that induction of lncRNAs after IR preceded changes in expression of adjacent genes. This indicates that IR-induced lncRNAs may regulate the transcription of nearby genes. Subcellular fractionation into chromatin, nuclear, and cytoplasmic fractions revealed that the majority of studied lncRNAs are localized in chromatin. In summary, our study revealed several lncRNAs induced by IR in an ATM-dependent manner. Their genomic co-localization and co-expression with genes involved in DDR suggest that those lncRNAs may be important players in cellular response to DNA damage.

Inhibition of the glutamate-cysteine ligase catalytic subunit with buthionine sulfoximine enhances the cytotoxic effect of doxorubicin and cyclophosphamide in Burkitt lymphoma cells.

Burkitt lymphoma (BL) is a highly aggressive lymphoma that mainly affects children and young adults. Chemotherapy is effective in young BL patients but the outcome in adults is less satisfactory. Therefore, there is a need to enhance the cytotoxic effect of drugs used in BL treatment. Glutathione (GSH) is an important antioxidant involved in processes such as regulation of oxidative stress and drug detoxification. Elevated GSH levels have been observed in many cancers and were associated with chemoresistance. We previously identified GCLC, encoding an enzyme involved in GSH biosynthesis, as an essential gene in BL. We now confirm that knockout of GCLC decreases viability of BL cells and that the GCLC protein is overexpressed in BL tissues. Moreover, we demonstrate that buthionine sulfoximine (BSO), a known inhibitor of GCLC, decreases growth of BL cells but does not affect control B cells. Furthermore, we show for the first time that BSO enhances the cytotoxicity of compounds commonly used in BL treatment, doxorubicin, and cyclophosphamide. Given the fact that BSO itself was not toxic to control cells and well-tolerated in clinical trials, combination of chemotherapy with BSO may allow reduction of the doses of cytotoxic drugs required to obtain effective responses in BL patients.

Cardiac Post-Chest Radiotherapy Complications in a 50-Year-Old Patient with Hodgkin Lymphoma.

Lymphomas are a group of malignant tumors that originate in the lymphatic system. It is the most common type of blood cancer. It affects the lymph nodes, spleen, bone marrow, blood, and other organs. They can be aggressive or chronic. Hodgkin lymphoma survival rate is 2 in 100,000 people. Young adults aged 20-30 and people over 50 are most often affected. The prognosis of Hodgkin's lymphoma is good, with a survival rate of up to 80 percent. Nevertheless, in 20-30 percent of patients who initially respond to treatment, the disease has a tendency to progress. The positive effect of radiotherapy (RT) on patients' survival rates has been proven in many randomized clinical trials. Although the dose of chest RT has significantly reduced over the years, we still struggle with the long-term complications of post-RT repercussions, mainly because there is no established safe dose of RT affecting the heart. Other complications include earlier onset of coronary artery disease, early and late onset of pericarditis, valve degeneration (predominantly of the left heart), calcification of the aorta and its branches, heart failure, and arrhythmias. One patient can manifest each of the abovementioned complications, as in the present case. That is why choosing the right treatment strategy is crucial.

CRISPR/Cas9 screen for genome-wide interrogation of essential MYC-bound E-boxes in cancer cells.

The transcription factor MYC is a proto-oncogene with a well-documented essential role in the pathogenesis and maintenance of several types of cancer. MYC binds to specific E-box sequences in the genome to regulate gene expression in a cell-type- and developmental-stage-specific manner. To date, a combined analysis of essential MYC-bound E-boxes and their downstream target genes important for growth of different types of cancer is missing. In this study, we designed a CRISPR/Cas9 library to destroy E-box sequences in a genome-wide fashion. In parallel, we used the Brunello library to knock out protein-coding genes. We performed high-throughput screens with these libraries in four MYC-dependent cancer cell lines-K562, ST486, HepG2, and MCF7-which revealed several essential E-boxes and genes. Among them, we pinpointed crucial common and cell-type-specific MYC-regulated genes involved in pathways associated with cancer development. Extensive validation of our approach confirmed that E-box disruption affects MYC binding, target-gene expression, and cell proliferation in vitro as well as tumor growth in vivo. Our unique, well-validated tool opens new possibilities to gain novel insights into MYC-dependent vulnerabilities in cancer cells.

Optimization of human myoblasts culture under different media conditions for application in the in vitro studies.

Human primary in vitro cell cultures are among the most challenging procedures in cellular biology laboratory practice. Myoblasts-progenitor of skeletal muscle origin represent a promising therapeutic cell source since the procedure of their isolation is not technically demanding, and the in vitro culture is relatively straightforward. Myoblasts could be considered as the candidates for clinical applications due to their regenerative potential, and as the carriers of therapeutic proteins introduced through genetic modifications. The main goal of this prospective study was to evaluate different myoblasts isolation strategies based on the pre-plating technique and cells density characteristics. Moreover, testing of different myoblast media formulations-both commercially available and in-house made was performed. Our goal was to establish the in vitro protocol of myoblasts culture allowing for preservation of the proliferative potential and desired phenotype. Our results revealed that in culture of myoblasts of human muscle origin, the pre-plate technique and cell density differences did not correlate with changes in the proliferative potential, however it was observed that low density cells maintained expression of the CD56 marker up to the higher passages. Assessment of different types of culture media confirmed the best performance for DMEM based media without Chicken Embryo Extract (CEE) addition. Cells cultured in DMEM+FBS medium revealed high expression of CD56 and CD90 antigens, absence of the hematopoietic markers and presented stable proliferation profile. This finding is in line with guidelines of regulatory agencies recommending removal of the xeno-derived reagents from the manufacturing process of Advanced Therapy Medicinal Products (ATMP). In this study, human myoblasts culture was optimized in vitro under different media conditions. The next approach in assessment of myoblasts propagation for potential clinical applications will be testing of the clinical grade human platelet lysate (hPL) instead of the FBS.

Multiparametric Evaluation of Post-MI Small Animal Models Using Metabolic ([18F]FDG) and Perfusion-Based (SYN1) Heart Viability Tracers.

Cardiovascular diseases (CVD), with myocardial infarction (MI) being one of the crucial components, wreak havoc in developed countries. Advanced imaging technologies are required to obtain quick and widely available diagnostic data. This paper describes a multimodal approach to in vivo perfusion imaging using the novel SYN1 tracer based on the fluorine-18 isotope. The NOD-SCID mice were injected intravenously with SYN1 or [18F] fluorodeoxyglucose ([18F]-FDG) radiotracers after induction of the MI. In all studies, the positron emission tomography-computed tomography (PET/CT) technique was used. To obtain hemodynamic data, mice were subjected to magnetic resonance imaging (MRI). Finally, the biodistribution of the SYN1 compound was performed using Wistar rat model. SYN1 showed normal accumulation in mouse and rat hearts, and MI hearts correctly indicated impaired cardiac segments when compared to [18F]-FDG uptake. In vivo PET/CT and MRI studies showed statistical convergence in terms of the size of the necrotic zone and cardiac function. This was further supported with RNAseq molecular analyses to correlate the candidate function genes' expression, with Serpinb1c, Tnc and Nupr1, with Trem2 and Aldolase B functional correlations showing statistical significance in both SYN1 and [18F]-FDG. Our manuscript presents a new fluorine-18-based perfusion radiotracer for PET/CT imaging that may have importance in clinical applications. Future research should focus on confirmation of the data elucidated here to prepare SYN1 for first-in-human trials.

Molecular imaging of myogenic stem/progenitor cells with [18F]-FHBG PET/CT system in SCID mice model of post-infarction heart.

Preclinical and clinical studies have shown that stem cells can promote the regeneration of damaged tissues, but therapeutic protocols need better quality control to confirm the location and number of transplanted cells. This study describes in vivo imaging while assessing reporter gene expression by its binding to a radiolabelled molecule to the respective receptor expressed in target cells. Five mice underwent human skeletal muscle-derived stem/progenitor cell (huSkMDS/PC EF1-HSV-TK) intracardial transplantation after induction of myocardial infarction (MI). The metabolic parameters of control and post-infarction stem progenitor cell-implanted mice were monitored using 2-deoxy-18F-fluorodeoxyglucose ([18F]-FDG) before and after double promotor/reporter probe imaging with 9-(4-18F-fluoro-3-[hydroxymethyl]butyl)guanine ([18F]-FHBG) using positron emission tomography (PET) combined with computed tomography (CT). Standardized uptake values (SUVs) were then calculated based on set regions of interest (ROIs). Experimental animals were euthanized after magnetic resonance imaging (MRI). Molecular [18F]-FHBG imaging of myogenic stem/progenitor cells in control and post-infarction mice confirmed the survival and proliferation of transplanted cells, as shown by an increased or stable signal from the PET apparatus throughout the 5 weeks of monitoring. huSkMDS/PC EF1-HSV-TK transplantation improved cardiac metabolic ([18F]-FDG with PET) and haemodynamic (MRI) parameters. In vivo PET/CT and MRI revealed that the precise use of a promotor/reporter probe incorporated into stem/progenitor cells may improve non-invasive monitoring of targeted cellular therapy in the cardiovascular system.

Molecular Imaging of Human Skeletal Myoblasts (huSKM) in Mouse Post-Infarction Myocardium.

Current treatment protocols for myocardial infarction improve the outcome of disease to some extent but do not provide the clue for full regeneration of the heart tissues. An increasing body of evidence has shown that transplantation of cells may lead to some organ recovery. However, the optimal stem cell population has not been yet identified. We would like to propose a novel pro-regenerative treatment for post-infarction heart based on the combination of human skeletal myoblasts (huSkM) and mesenchymal stem cells (MSCs). huSkM native or overexpressing gene coding for Cx43 (huSKMCx43) alone or combined with MSCs were delivered in four cellular therapeutic variants into the healthy and post-infarction heart of mice while using molecular reporter probes. Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) performed right after cell delivery and 24 h later revealed a trend towards an increase in the isotopic uptake in the post-infarction group of animals treated by a combination of huSkMCx43 with MSC. Bioluminescent imaging (BLI) showed the highest increase in firefly luciferase (fluc) signal intensity in post-infarction heart treated with combination of huSkM and MSCs vs. huSkM alone (p < 0.0001). In healthy myocardium, however, nanoluciferase signal (nanoluc) intensity varied markedly between animals treated with stem cell populations either alone or in combinations with the tendency to be simply decreased. Therefore, our observations seem to show that MSCs supported viability, engraftment, and even proliferation of huSkM in the post-infarction heart.

Assessment of Immunological Potential of Glial Restricted Progenitor Graft In Vivo-Is Immunosuppression Mandatory?

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease, causing motor neuron and skeletal muscle loss and death. One of the promising therapeutic approaches is stem cell graft application into the brain; however, an immune reaction against it creates serious limitations. This study aimed to research the efficiency of glial restricted progenitors (GRPs) grafted into murine CNS (central nervous system) in healthy models and the SOD1G93A ALS disease model. The cellular grafts were administered in semiallogenic and allogeneic settings. To investigate the models of immune reaction against grafted GRPs, we applied three immunosuppressive/immunomodulatory regimens: preimplantation factor (PiF); Tacrolimus; and CTLA-4, MR1 co-stimulatory blockade. We tracked the cells with bioluminescence imaging (BLI) in vivo to study their survival. The immune response character was evaluated with brain tissue assays and multiplex ELISA in serum and cerebrospinal fluid (CSF). The application of immunosuppressive drugs is disputable when considering cellular transplants into the immune-privileged site/brain. However, our data revealed that semiallogenic GRP graft might survive inside murine CNS without the necessity to apply any immunomodulation or immunosuppression, whereas, in the situation of allogeneic mouse setting, the combination of CTLA-4, MR1 blockade can be considered as the best immunosuppressive option.

Deregulated miRNAs Contribute to Silencing of B-Cell Specific Transcription Factors and Activation of NF-κB in Classical Hodgkin Lymphoma.

A hallmark of classical Hodgkin lymphoma (cHL) is the attenuation of B-cell transcription factors leading to global transcriptional reprogramming. The role of miRNAs (microRNAs) involved in this process is poorly studied. Therefore, we performed global miRNA expression profiling using RNA-seq on commonly used cHL cell lines, non-Hodgkin lymphoma cell lines and sorted normal CD77+ germinal centre B-cells as controls and characterized the cHL miRNome (microRNome). Among the 298 miRNAs expressed in cHL, 56 were significantly overexpressed and 23 downregulated (p < 0.05) compared to the controls. Moreover, we identified five miRNAs (hsa-miR-9-5p, hsa-miR-24-3p, hsa-miR-196a-5p, hsa-miR-21-5p, hsa-miR-155-5p) as especially important in the pathogenesis of this lymphoma. Target genes of the overexpressed miRNAs in cHL were significantly enriched (p < 0.05) in gene ontologies related to transcription factor activity. Therefore, we further focused on selected interactions with the SPI1 and ELF1 transcription factors attenuated in cHL and the NF-ĸB inhibitor TNFAIP3. We confirmed the interactions between hsa-miR-27a-5p:SPI1, hsa-miR-330-3p:ELF-1, hsa-miR-450b-5p:ELF-1 and hsa-miR-23a-3p:TNFAIP3, which suggest that overexpression of these miRNAs contributes to silencing of the respective genes. Moreover, by analyzing microdissected HRS cells, we demonstrated that these miRNAs are also overexpressed in primary tumor cells. Therefore, these miRNAs play a role in silencing the B-cell phenotype in cHL.

Hypoxia-Induced FAM13A Regulates the Proliferation and Metastasis of Non-Small Cell Lung Cancer Cells.

Hypoxia in non-small cell lung cancer (NSCLC) affects cancer progression, metastasis and metabolism. We previously showed that FAM13A was induced by hypoxia in NSCLC but the biological function of this gene has not been fully elucidated. This study aimed to investigate the role of hypoxia-induced FAM13A in NSCLC progression and metastasis. Lentiviral shRNAs were used for FAM13A gene silencing in NSCLC cell lines (A549, CORL-105). MTS assay, cell tracking VPD540 dye, wound healing assay, invasion assay, BrdU assay and APC Annexin V staining assays were performed to examine cell proliferation ability, migration, invasion and apoptosis rate in NSCLC cells. The results of VPD540 dye and MTS assays showed a significant reduction in cell proliferation after FAM13A knockdown in A549 cells cultured under normal and hypoxia (1% O2) conditions (p < 0.05), while the effect of FAM13A downregulation on CORL-105 cells was observed after 96 h exposition to hypoxia. Moreover, FAM13A inhibition induced S phase cell cycle arrest in A549 cells under hypoxia conditions. Silencing of FAM13A significantly suppressed migration of A549 and CORL-105 cells in both oxygen conditions, especially after 72 and 96 h (p < 0.001 in normoxia, p < 0.01 after hypoxia). It was showed that FAM13A reduction resulted in disruption of the F-actin cytoskeleton altering A549 cell migration. Cell invasion rates were significantly decreased in A549 FAM13A depleted cells compared to controls (p < 0.05), mostly under hypoxia. FAM13A silencing had no effect on apoptosis induction in NSCLC cells. In the present study, we found that FAM13A silencing has a negative effect on proliferation, migration and invasion activity in NSCLC cells in normal and hypoxic conditions. Our data demonstrated that FAM13A depleted post-hypoxic cells have a decreased cell proliferation ability and metastatic potential, which indicates FAM13A as a potential therapeutic target in lung cancer.

Mesenchymal Stromal Cells from Different Parts of Umbilical Cord: Approach to Comparison & Characteristics.

Mesenchymal stromal/stem cells (MSCs) are a unique population of cells that play an important role in the regeneration potential of the body. MSCs exhibit a characteristic phenotype and are capable of modulating the immune response. MSCs can be isolated from various tissues such as: bone marrow, adipose tissue, placenta, umbilical cord and others. The umbilical cord as a source of MSCs, has strong advantages, such as no-risk procedure of tissue retrieval after birth and easiness of the MSCs isolation. As the umbilical cord (UC) is a complex organ and we decided to evaluate, whether the cells derived from different regions of umbilical cord show similar or distinct properties. In this study we characterized and compared MSCs from three regions of the umbilical cord: Wharton's Jelly (WJ), the perivascular space (PRV) and the umbilical membrane (UCM). The analysis was carried out in terms of morphology, phenotype, immunomodulation potential and secretome. Based on the obtained results, we were able to conclude, that MSCs derived from distinct UC regions differ in their properties. According to our result WJ-MSCs have high and stabile proliferation potential and phenotype, when compare with other MSCs and can be treated as a preferable source of cells for medical application.

Assessment of the Neuroprotective and Stemness Properties of Human Wharton's Jelly-Derived Mesenchymal Stem Cells under Variable (5% vs. 21%) Aerobic Conditions.

To optimise the culture conditions for human Wharton's jelly-derived mesenchymal stem cells (hWJ-MSCs) intended for clinical use, we investigated ten different properties of these cells cultured under 21% (atmospheric) and 5% (physiological normoxia) oxygen concentrations. The obtained results indicate that 5% O2 has beneficial effects on the proliferation rate, clonogenicity, and slowdown of senescence of hWJ-MSCs; however, the oxygen level did not have an influence on the cell morphology, immunophenotype, or neuroprotective effect of the hWJ-MSCs. Nonetheless, the potential to differentiate into adipocytes, osteocytes, and chondrocytes was comparable under both oxygen conditions. However, spontaneous differentiation of hWJ-MSCs into neuronal lineages was observed and enhanced under atmospheric oxygen conditions. The cells relied more on mitochondrial respiration than glycolysis, regardless of the oxygen conditions. Based on these results, we can conclude that hWJ-MSCs could be effectively cultured and prepared under both oxygen conditions for cell-based therapy. However, the 5% oxygen level seemed to create a more balanced and appropriate environment for hWJ-MSCs.

Chromatin and transcriptome changes in human myoblasts show spatio-temporal correlations and demonstrate DPP4 inhibition in differentiated myotubes.

Although less attention was paid to understanding physical localization changes in cell nuclei recently, depicting chromatin interaction maps is a topic of high interest. Here, we focused on defining extensive physical changes in chromatin organization in the process of skeletal myoblast differentiation. Based on RNA profiling data and 3D imaging of myogenic (NCAM1, DES, MYOG, ACTN3, MYF5, MYF6, ACTN2, and MYH2) and other selected genes (HPRT1, CDH15, DPP4 and VCAM1), we observed correlations between the following: (1) expression change and localization, (2) a gene and its genomic neighbourhood expression and (3) intra-chromosome and microscopical locus-centromere distances. In particular, we demonstrated the negative regulation of DPP4 mRNA (p < 0.001) and protein (p < 0.05) in differentiated myotubes, which coincided with a localization change of the DPP4 locus towards the nuclear lamina (p < 0.001) and chromosome 2 centromere (p < 0.001). Furthermore, we discuss the possible role of DPP4 in myoblasts (supported by an inhibition assay). We also provide positive regulation examples (VCAM1 and MYH2). Overall, we describe for the first time existing mechanisms of spatial gene expression regulation in myoblasts that might explain the issue of heterogenic responses observed during muscle regenerative therapies.

Upregulation of FOXO3 in New-Onset Type 1 Diabetes Mellitus.

Forkhead box O (FOXO) transcription factors have been implicated in the development and differentiation of the immune cells. FOXO3 plays a crucial role in physiologic and pathologic immune response. FOXO3, cooperatively with FOXO1, control the development and function of Foxp3+ regulatory T cells (Treg). Since the lack of Treg-mediated control has fundamental impact on type 1 diabetes mellitus (T1DM) development, we investigated FOXO3 expression in patients with T1DM. FOXO3 expression was estimated in peripheral blood mononuclear cells (PBMCs) from newly diagnosed T1DM pediatric patients (n = 28) and age-matched healthy donors (n = 27) by reahavel-time PCR and TaqMan gene expression assays. Expression analysis revealed significant upregulation of FOXO3 in T1DM (P = 0.0005). Stratification of the T1DM group according to the presence of initial diabetic ketoacidosis (DKA) did not indicate differences in FOXO3 expression in patients with DKA compared to a mild T1DM onset (P > 0.05). In conclusion, overexpression of FOXO3 is correlated with the ongoing islet autoimmune destruction and might suggest a potential role for this gene in the pathogenesis of type 1 diabetes mellitus.

Bioevaluation of superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with dihexadecyl phosphate (DHP).

Superparamagnetic iron oxide nanoparticles (SPIONs) have been investigated for wide variety of applications. Their unique properties render them highly applicable as MRI contrast agents, in magnetic hyperthermia or targeted drug delivery. SPIONs surface properties affect a whole array of parameters such as: solubility, toxicity, stability, biodistribution etc. Therefore, progress in the field of SPIONs surface functionalization is crucial for further development of therapeutic or diagnostic agents. In this study, SPIONs were synthesized by thermal decomposition of iron (III) acetylacetonate Fe(acac)3 and functionalized with dihexadecyl phosphate (DHP) via phase transfer. Bioactivity of the SPION-DHP was assessed on SW1353 and TCam-2 cancer derived cell lines. The following test were conducted: cytotoxicity and proliferation assay, reactive oxygen species (ROS) assay, SPIONs uptake (via Iron Staining and ICP-MS), expression analysis of the following genes: alkaline phosphatase (ALPL); ferritin light chain (FTL); serine/threonine protein phosphatase 2A (PP2A); protein tyrosine phosphatase non-receptor type 11 (PTPN11); transferrin receptor 1 (TFRC) via RT-qPCR. SPION-DHP nanoparticles were successfully obtained and did not reveal significant cytotoxicity in the range of tested concentrations. ROS generation was elevated, however not correlated with the concentrations. Gene expression profile was slightly altered only in SW1353 cells.

The impact of in vitro cell culture duration on the maturation of human cardiomyocytes derived from induced pluripotent stem cells of myogenic origin.

Ischemic heart disease, also known as coronary artery disease (CAD), poses a challenge for regenerative medicine. iPSC technology might lead to a breakthrough due to the possibility of directed cell differentiation delivering a new powerful source of human autologous cardiomyocytes. One of the factors supporting proper cell maturation is in vitro culture duration. In this study, primary human skeletal muscle myoblasts were selected as a myogenic cell type reservoir for genetic iPSC reprogramming. Skeletal muscle myoblasts have similar ontogeny embryogenetic pathways (myoblasts vs. cardiomyocytes), and thus, a greater chance of myocardial development might be expected, with maintenance of acquired myogenic cardiac cell characteristics, from the differentiation process when iPSCs of myoblastoid origin are obtained. Analyses of cell morphological and structural changes, gene expression (cardiac markers), and functional tests (intracellular calcium transients) performed at two in vitro culture time points spanning the early stages of cardiac development (day 20 versus 40 of cell in vitro culture) confirmed the ability of the obtained myogenic cells to acquire adult features of differentiated cardiomyocytes. Prolonged 40-day iPSC-derived cardiomyocytes (iPSC-CMs) revealed progressive cellular hypertrophy; a better-developed contractile apparatus; expression of marker genes similar to human myocardial ventricular cells, including a statistically significant CX43 increase, an MHC isoform switch, and a troponin I isoform transition; more efficient intercellular calcium handling; and a stronger response to ß-adrenergic stimulation.

Potential use of superparamagnetic iron oxide nanoparticles for in vitro and in vivo bioimaging of human myoblasts.

Myocardial infarction (MI) is one of the most frequent causes of death in industrialized countries. Stem cells therapy seems to be very promising for regenerative medicine. Skeletal myoblasts transplantation into postinfarction scar has been shown to be effective in the failing heart but shows limitations such, e.g. cell retention and survival. We synthesized and investigated superparamagnetic iron oxide nanoparticles (SPIONs) as an agent for direct cell labeling, which can be used for stem cells imaging. High quality, monodisperse and biocompatible DMSA-coated SPIONs were obtained with thermal decomposition and subsequent ligand exchange reaction. SPIONs' presence within myoblasts was confirmed by Prussian Blue staining and inductively coupled plasma mass spectrometry (ICP-MS). SPIONs' influence on tested cells was studied by their proliferation, ageing, differentiation potential and ROS production. Cytotoxicity of obtained nanoparticles and myoblast associated apoptosis were also tested, as well as iron-related and coating-related genes expression. We examined SPIONs' impact on overexpression of two pro-angiogenic factors introduced via myoblast electroporation method. Proposed SPION-labeling was sufficient to visualize firefly luciferase-modified and SPION-labeled cells with magnetic resonance imaging (MRI) combined with bioluminescence imaging (BLI) in vivo. The obtained results demonstrated a limited SPIONs' influence on treated skeletal myoblasts, not interfering with basic cell functions.

Biological and Pro-Angiogenic Properties of Genetically Modified Human Primary Myoblasts Overexpressing Placental Growth Factor in In Vitro and In Vivo Studies.

Cardiovascular diseases are a growing problem in developing countries; therefore, there is an ongoing intensive search for new approaches to treat these disorders. Currently, cellular therapies are focused on healing the damaged heart by implanting stem cells modified with pro-angiogenic factors. This approach ensures that the introduced cells are capable of fulfilling the complex requirements of the environment, including the replacement of the post-infarction scar with cells that are able to contract and promote the formation of new blood vessels that can supply the ischaemic region with nutrients and oxygen. This study focused on the genetic modification of human skeletal muscle cells (SkMCs). We chose myoblast cells due to their close biological resemblance to cardiomyocytes and the placental growth factor (PlGF) gene due to its pro-angiogenic potential. In our in vitro studies, we transfected SkMCs with the PlGF gene using electroporation, which has previously been proven to be efficient and generate robust overexpression of the PlGF gene and elevate PlGF protein secretion. Moreover, the functionality of the secreted pro-angiogenic proteins was confirmed using an in vitro capillary development assay. We have also examined the influence of PlGF overexpression on VEGF-A and VEGF-B, which are well-known factors described in the literature as the most potent activators of blood vessel formation. We were able to confirm the overexpression of VEGF-A in myoblasts transfected with the PlGF gene. The results obtained in this study were further verified in an animal model. These data were able to confirm the potential therapeutic effects of the applied treatments.

Safety, feasibility and effectiveness of first in-human administration of muscle-derived stem/progenitor cells modified with connexin-43 gene for treatment of advanced chronic heart failure.

AIMS: To assess the safety and efficacy of transendocardial delivery of muscle-derived stem/progenitor cells with connexin-43 overexpression (Cx-43-MDS/PC) in advanced heart failure (HF). METHODS AND RESULTS: Thirteen subjects with advanced HF, New York Heart Association (NYHA) class II-III were enrolled and treated with targeted injection of Cx-43-MDS/PCs and then monitored for at least 6 months. Overexpression of Cx43 (Cx43+) was significantly higher in all but one subject (Cx43-). Injection of MDS/PCs was associated with significant improvement of exercise capacity: NYHA (3 ± 0 vs. 1.8 ± 0.7, P = 0.003), exercise duration (388.69 ± 141.83 s vs. 462.08 ± 176.69 s, P = 0.025), peak oxygen consumption (14.38 ± 3.97 vs. 15.83 ± 3.74 ml/kg.min, P = 0.022) and oxygen pulse (10.58 ± 2.89 vs. 18.88 ± 22.63 mLO2 /heart rate, P = 0.012). Levels of BNP, left ventricular (LV) ejection fraction and LV end-diastolic volumes tended to improve. There was a significant improvement of the mean unipolar voltage amplitudes measured for the injected segments and the entire left ventricle (9.62 ± 2.64 vs. 11.62 ± 3.50 mV, P = 0.014 and 8.83 ± 2.80 vs. 10.22 ± 3.41 mV, P = 0.041, respectively). No deaths were documented, Cx43+ (n = 12) subjects presented no significant ventricular arrhythmia; one Cx43- subject suffered from ventricular tachycardia (successfully treated with amiodarone). CONCLUSIONS: Injection of Cx-43-MDS/PCs in patients with severe HF led to significant improvement in exercise capacity and myocardial viability of the injected segments while inducing no significant ventricular arrhythmia. This may arise from improved electrical coupling of the injected cells and injured myocardium and thus better in-situ mechanical cooperation of both cell types. Therefore, further clinical studies with Cx43+ MDS/PCs are warranted.