Myomir dysregulation and reactive oxygen species in aged human satellite cells

Satellite cells that reside on the myofibre surface are crucial for the muscle homeostasis and regeneration. Aging goes along with a less effective regeneration of skeletal muscle tissue mainly due to the decreased myogenic capability of satellite cells. This phenomenon impedes proper maintenance and contributes to the age-associated decline in muscle mass, known as sarcopenia. The myogenic potential impairment does not depend on a reduced myogenic cell number, but mainly on their difficulty to complete a differentiation program. The unbalanced production of reactive oxygen species in elderly people could be responsible for skeletal muscle impairments. microRNAs are conserved post-transcriptional regulators implicated in numerous biological processes including adult myogenesis. Here, we measure the ROS level and analyze myomiR (miR-1, miR-133b and miR-206) expression in human myogenic precursors obtained from Vastus lateralis of elderly and young subjects to provide the molecular signature responsible for the differentiation impairment of elderly activated satellite cells. publisher: Elsevier articletitle: Myomir dysregulation and reactive oxygen species in aged human satellite cells journaltitle: Biochemical and Biophysical Research Communications articlelink: http://dx.doi.org/10.1016/j.bbrc.2016.03.030 content_type: article copyright: Copyright © 2016 The Authors. Published by Elsevier Inc. ispartof: Biochemical and Biophysical Research Communications vol:473 issue:2 pages:462-70 ispartof: location:United States status: publishe

Cell therapy strategies and improvements for muscular dystrophy

Understanding stem cell commitment and differentiation is a critical step towards clinical translation of cell therapies. In past few years, several cell types have been characterized and transplanted in animal models for different diseased tissues, eligible for a cell-mediated regeneration. Skeletal muscle damage is a challenge for cell- and gene-based therapeutical approaches, given the unique architecture of the tissue and the clinical relevance of acute damages or dystrophies. In this review, we will consider the regenerative potential of embryonic and somatic stem cells and the outcomes achieved on their transplantation into animal models for muscular dystrophy or acute muscle impairment

Alteration of Cardiac Progenitor Cell Potency in GRMD Dogs

n/

Metabolomic profile of amniotic fluid to evaluate lung maturity: the diaphragmatic hernia lamb model

Background: Tracheal occlusion (TO) stimulates lung growth in fetuses affected with congenital diaphragmatic hernia (CDH) although the processes involved in lung maturation still remain unknown. The objective of this study was to evaluate the metabolomic profile of amniotic fluid (AF) following TO in fetal lamb model in order to obtain an indirect view of mechanisms involved in pulmonary reversal hypoplasia and biochemical maturity in response to fetal TO. Methods: Liquid Chromatography Mass Spectrometry was performed on lamb AF samples at: age I (70 days' gestation); age II (102 days' gestation); age III (136 days' gestation). CDH was induced at age I and TO at age II. Results: Betaine, choline, creatinine were found significantly increased during gestation in the control group. The CDH group showed choline (p =0.007) and creatinine (p =0.004) decreases during pregnancy. In the TO group choline and creatinine profiles were restored. Conclusions: Alveolar tissue and fetal global growth ameliorated after TO. Metabolomics provided usefu information on biochemical details during lung maturation. Metabolomic profiling would help to identify the best time to perform TO, in order to increase survival of CDH affected patients

Zeb2 regulates myogenic differentiation in pluripotent stem cells

Skeletal muscle differentiation is triggered by a unique family of myogenic basic helix-loop-helix transcription factors, including MyoD, MRF-4, Myf-5, and Myogenin. These transcription factors bind promoters and distant regulatory regions, including E-box elements, of genes whose expression is restricted to muscle cells. Other E-box binding zinc finger proteins target the same DNA response elements, however, their function in muscle development and regeneration is still unknown. Here, we show that the transcription factor zinc finger E-box-binding homeobox 2 (Zeb2, Sip-1, Zfhx1b) is present in skeletal muscle tissues. We investigate the role of Zeb2 in skeletal muscle differentiation using genetic tools and transgenic mouse embryonic stem cells, together with single-cell RNA-sequencing and in vivo muscle engraftment capability. We show that Zeb2 over-expression has a positive impact on skeletal muscle differentiation in pluripotent stem cells and adult myogenic progenitors. We therefore propose that Zeb2 is a novel myogenic regulator and a possible target for improving skeletal muscle regeneration. The non-neural roles of Zeb2 are poorly understood

Tocilizumab or glucocorticoids treatment for patients with SARS-CoV-2 pneumonia: An observational study

Objective: To estimate the effect of tocilizumab or glucocorticoids in preventing death and intubation in patients hospitalized with SARS-CoV-2 pneumonia.Methods: This was a retrospective cohort study enrolling all consecutive patients hospitalized at Reggio Emilia AUSL between February the 11th and April 14th 2020 for severe COVID19 and treated with tocilizumab or glucocorticoids (at least 80 mg/day of methylprednisolone or equivalent for at least 3 days).The primary outcome was death within 30 days from the start of the considered therapies. The secondary outcome was a composite outcome of death and/or intubation. All patients have been followed-up until May 19th 2020, with a follow-up of at least 30 days for every patient. To reduce confounding due to potential non-comparability of the two groups, those receiving tocilizumab and those receiving glucocorticoids, a propensity score was calculated as the inverse probability weighting of receiving treatment conditional on the baseline covariates.Results and conclusion: Therapy with tocilizumab alone was associated with a reduction of deaths (OR 0.49, 95% CI 0.21-1.17) and of the composite outcome death/intubation (OR 0.35, 95% CI 0.13-0.90) compared to glucocorticoids alone. Nevertheless, this result should be cautiously interpreted due to a potential prescription bias.(c) 2021 Sociedade Brasileira de Infectologia. Published by Elsevier Espana, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/

Met-activating genetically improved chimeric factor-1 promotes angiogenesis and hypertrophy in adult myogenesis

BACKGROUND: Myogenic progenitor cells (activated satellite cells) are able to express both HGF and its receptor cMet. After muscle injury, HGF-Met stimulation promotes activation and primary division of satellite cells. MAGIC-F1 (Met-Activating Genetically Improved Chimeric Factor-1) is an engineered protein that contains two human Met-binding domains that promotes muscle hypertrophy. MAGIC-F1 protects myogenic precursors against apoptosis and increases their fusion ability enhancing muscle differentiation. Hemizygous and homozygous Magic-F1 transgenic mice displayed constitutive muscle hypertrophy. METHODS: Here we describe microarray analysis on Magic-F1 myogenic progenitor cells showing an altered gene signatures on muscular hypertrophy and angiogenesis compared to wild-type cells. In addition, we performed a functional analysis on Magic-F1+/+ transgenic mice versus controls using treadmill test. RESULTS: We demonstrated that Magic-F1+/+ mice display an increase in muscle mass and cross-sectional area leading to an improvement in running performance. Moreover, the presence of MAGIC-F1 affected positively the vascular network, increasing the vessel number in fast twitch fibers. Finally, the gene expression profile analysis of Magic-F1+/+ satellite cells evidenced transcriptomic changes in genes involved in the control of muscle growth, development and vascularisation. CONCLUSION: We showed that MAGIC -F1-induced muscle hypertrophy affects positively vascular network, increasing vessel number in fast twitch fibers. This was due to unique features of mammalian skeletal muscle and its remarkable ability to adapt promptly to different physiological demands by modulating the gene expression profile in myogenic progenitors

Impact of atrial fibrillation in critically ill patients admitted to a stepdown unit

Background: Limited data are available on the clinical course of patients with history of atrial fibrillation (AF) when admitted in an intensive care environment. We aimed to describe the occurrence of major adverse events in AF patients admitted to a stepdown care unit (SDU) and to analyse clinical factors associated with outcomes, impact of dicumarolic oral anticoagulant (OAC) therapy impact and performance of clinical risk scores in this setting. Materials and methods: Single-centre, observational retrospective analysis on a population of subjects with AF history admitted to a SDU. Therapeutic failure (composite of transfer to ICU or death) was considered the main study outcome. Occurrence of stroke and major bleeding (MH) was considered as secondary outcomes. The performance of clinical risk scores was evaluated. Results: A total of 1430 consecutive patients were enrolled. 194 (13.6%) reported the main outcome. Using multivariate logistic regression, age (odds ratio [OR]: 1.03, 95% confidence interval [CI]: 1.01-1.05), acute coronary syndrome (OR:3.10, 95% CI: 1.88-5.12), cardiogenic shock (OR:10.06, 95% CI: 5.37-18.84), septic shock (OR:5.19,95%CI:3.29-18.84), acute respiratory failure (OR:2.49, 95% CI: 1.67-3.64) and OAC use (OR: 1.61, 95% CI: 1.02-2.55) were independently associated with main outcome. OAC prescription was associated with stroke risk reduction and to both MH and main outcome risk increase. CHA2 DS2 -VASc (c-index: 0.545, P = .117 for stroke) and HAS-BLED (c-index:0.503, P = .900 for MH) did not significantly predict events occurrence. Conclusions: In critically ill AF patients admitted to a SDU, adverse outcomes are highly prevalent. OAC use is associated to an increased risk of therapeutic failure, clinical scores seem unhelpful in predicting stroke and MH, suggesting a highly individualized approach in AF management in this setting

The human somatostatin receptor type 2 as an imaging and suicide reporter gene for pluripotent stem cell-derived therapy of myocardial infarction

Rationale: Pluripotent stem cells (PSCs) are being investigated as a cell source for regenerative medicine since they provide an infinitive pool of cells that are able to differentiate towards every cell type of the body. One possible therapeutic application involves the use of these cells to treat myocardial infarction (MI), a condition where billions of cardiomyocytes (CMs) are lost. Although several protocols have been developed to differentiate PSCs towards CMs, none of these provide a completely pure population, thereby still posing a risk for neoplastic teratoma formation. Therefore, we developed a strategy to (i) monitor cell behavior noninvasively via site-specific integration of firefly luciferase (Fluc) and the human positron emission tomography (PET) imaging reporter genes, sodium iodide symporter (hNIS) and somatostatin receptor type 2 (hSSTr2), and (ii) perform hSSTr2-mediated suicide gene therapy via the clinically used radiopharmacon 177Lu-DOTATATE. Methods: Human embryonic stem cells (ESCs) were gene-edited via zinc finger nucleases to express Fluc and either hNIS or hSSTr2 in the safe harbor locus, adeno-associated virus integration site 1. Firstly, these cells were exposed to 4.8 MBq 177Lu-DOTATATE in vitro and cell survival was monitored via bioluminescence imaging (BLI). Afterwards, hNIS+ and hSSTr2+ ESCs were transplanted subcutaneously and teratomas were allowed to form. At day 59, baseline 124I and 68Ga-DOTATATE PET and BLI scans were performed. The day after, animals received either saline or 55 MBq 177Lu-DOTATATE. Weekly BLI scans were performed, accompanied by 124I and 68Ga-DOTATATE PET scans at days 87 and 88, respectively. Finally, hSSTr2+ ESCs were differentiated towards CMs and transplanted intramyocardially in the border zone of an infarct that was induced by left anterior descending coronary artery ligation. After transplantation, the animals were monitored via BLI and PET, while global cardiac function was evaluated using cardiac magnetic resonance imaging. Results: Teratoma growth of both hNIS+ and hSSTr2+ ESCs could be followed noninvasively over time by both PET and BLI. After 177Lu-DOTATATE administration, successful cell killing of the hSSTr2+ ESCs was achieved both in vitro and in vivo, indicated by reductions in total tracer lesion uptake, BLI signal and teratoma volume. As undifferentiated hSSTr2+ ESCs are not therapeutically relevant, they were differentiated towards CMs and injected in immune-deficient mice with a MI. Long-term cell survival could be monitored without uncontrolled cell proliferation. However, no improvement in the left ventricular ejection fraction was observed.Conclusion: We developed isogenic hSSTr2-expressing ESCs that allow noninvasive cell monitoring in the context of PSC-derived regenerative therapy. Furthermore, we are the first to use the hSSTr2 not only as an imaging reporter gene, but also as a suicide mechanism for radionuclide therapy in the setting of PSC-derived cell treatment

Long-term miR-669a therapy alleviates chronic dilated cardiomyopathy in dystrophic mice.

BACKGROUND: Dilated cardiomyopathy (DCM) is a leading cause of chronic morbidity and mortality in muscular dystrophy (MD) patients. Current pharmacological treatments are not yet able to counteract chronic myocardial wastage, thus novel therapies are being intensely explored. MicroRNAs have been implicated as fine regulators of cardiomyopathic progression. Previously, miR-669a downregulation has been linked to the severe DCM progression displayed by Sgcb-null dystrophic mice. However, the impact of long-term overexpression of miR-669a on muscle structure and functionality of the dystrophic heart is yet unknown. METHODS AND RESULTS: Here, we demonstrate that intraventricular delivery of adeno-associated viral (AAV) vectors induces long-term (18 months) miR-669a overexpression and improves survival of Sgcb-null mice. Treated hearts display significant decrease in hypertrophic remodeling, fibrosis, and cardiomyocyte apoptosis. Moreover, miR-669a treatment increases sarcomere organization, reduces ventricular atrial natriuretic peptide (ANP) levels, and ameliorates gene/miRNA profile of DCM markers. Furthermore, long-term miR-669a overexpression significantly reduces adverse remodeling and enhances systolic fractional shortening of the left ventricle in treated dystrophic mice, without significant detrimental consequences on skeletal muscle wastage. CONCLUSIONS: Our findings provide the first evidence of long-term beneficial impact of AAV-mediated miRNA therapy in a transgenic model of severe, chronic MD-associated DCM