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

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Activator Protein-1 Transcriptional Activity Drives Soluble Micrograft-Mediated Cell Migration and Promotes the Matrix Remodeling Machinery

Impaired wound healing and tissue regeneration have severe consequences on the patient's quality of life. Micrograft therapies are emerging as promising and affordable alternatives to improve skin regeneration by enhancing the endogenous wound repair processes. However, the molecular mechanisms underpinning the beneficial effects of the micrograft treatments remain largely unknown. In this study, we identified the active protein-1 (AP-1) member Fos-related antigen-1 (Fra-1) to play a central role in the extracellular signal-regulated kinase- (ERK-) mediated enhanced cell migratory capacity of soluble micrograft-treated mouse adult fibroblasts and in the human keratinocyte cell model. Accordingly, we show that increased micrograft-dependent in vitro cell migration and matrix metalloprotease activity is abolished upon inhibition of AP-1. Furthermore, soluble micrograft treatment leads to increased expression and posttranslational phosphorylation of Fra-1 and c-Jun, resulting in the upregulation of wound healing-associated genes mainly involved in the regulation of cell migration. Collectively, our work provides insights into the molecular mechanisms behind the cell-free micrograft treatment, which might contribute to future advances in wound repair therapies

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

In vivo stem cell tracking using scintigraphy in a canine model of DMD

One of the main challenges in cell therapy for muscle diseases is to efficiently target the muscle. To address this issue and achieve better understanding of in vivo cell fate, we evaluated the relevance of a non-invasive cell tracking method in the Golden Retriever Muscular Dystrophy (GRMD) model, a well-recognised model of Duchenne Muscular Dystrophy (DMD). Mesoangioblasts were directly labelled with 111In-oxine, and injected through one of the femoral arteries. The scintigraphy images obtained provided the first quantitative mapping of the immediate biodistribution of mesoangioblasts in a large animal model of DMD. The results revealed that cells were trapped by the first capillary filters: the injected limb and the lung. During the days following injection, radioactivity was redistributed to the liver. In vitro studies, performed with the same cells prepared for injecting the animal, revealed prominent cell death and 111In release. In vivo, cell death resulted in 111In release into the vasculature that was taken up by the liver, resulting in a non-specific and non-cell-bound radioactive signal. Indirect labelling methods would be an attractive alternative to track cells on the mid- and long-term

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