Deletion of SA β-Gal+ Cells Using Senolytics Improves Muscle Regeneration in Old Mice

Systemic deletion of senescent cells leads to robust improvements in cognitive, cardiovascular, and whole-body metabolism, but their role in tissue reparative processes is incompletely understood. We hypothesized that senolytic drugs would enhance regeneration in aged skeletal muscle. Young (3 months) and old (20 months) male C57Bl/6J mice were administered the senolytics dasatinib (5 mg/kg) and quercetin (50 mg/kg) or vehicle bi-weekly for 4 months. Tibialis anterior (TA) was then injected with 1.2% BaCl2 or PBS 7- or 28 days prior to euthanization. Senescence-associated β-Galactosidase positive (SA β-Gal+) cell abundance was low in muscle from both young and old mice and increased similarly 7 days following injury in both age groups, with no effect of D+Q. Most SA β-Gal+ cells were also CD11b+ in young and old mice 7- and 14 days following injury, suggesting they are infiltrating immune cells. By 14 days, SA β-Gal+/CD11b+ cells from old mice expressed senescence genes, whereas those from young mice expressed higher levels of genes characteristic of anti-inflammatory macrophages. SA β-Gal+ cells remained elevated in old compared to young mice 28 days following injury, which were reduced by D+Q only in the old mice. In D+Q-treated old mice, muscle regenerated following injury to a greater extent compared to vehicle-treated old mice, having larger fiber cross-sectional area after 28 days. Conversely, D+Q blunted regeneration in young mice. In vitro experiments suggested D+Q directly improve myogenic progenitor cell proliferation. Enhanced physical function and improved muscle regeneration demonstrate that senolytics have beneficial effects only in old mice

The impact of transposable element activity on therapeutically relevant human stem cells

Human stem cells harbor significant potential for basic and clinical translational research as well as regenerative medicine. Currently ~ 3000 adult and ~ 30 pluripotent stem cell-based, interventional clinical trials are ongoing worldwide, and numbers are increasing continuously. Although stem cells are promising cell sources to treat a wide range of human diseases, there are also concerns regarding potential risks associated with their clinical use, including genomic instability and tumorigenesis concerns. Thus, a deeper understanding of the factors and molecular mechanisms contributing to stem cell genome stability are a prerequisite to harnessing their therapeutic potential for degenerative diseases. Chemical and physical factors are known to influence the stability of stem cell genomes, together with random mutations and Copy Number Variants (CNVs) that accumulated in cultured human stem cells. Here we review the activity of endogenous transposable elements (TEs) in human multipotent and pluripotent stem cells, and the consequences of their mobility for genomic integrity and host gene expression. We describe transcriptional and post-transcriptional mechanisms antagonizing the spread of TEs in the human genome, and highlight those that are more prevalent in multipotent and pluripotent stem cells. Notably, TEs do not only represent a source of mutations/CNVs in genomes, but are also often harnessed as tools to engineer the stem cell genome; thus, we also describe and discuss the most widely applied transposon-based tools and highlight the most relevant areas of their biomedical applications in stem cells. Taken together, this review will contribute to the assessment of the risk that endogenous TE activity and the application of genetically engineered TEs constitute for the biosafety of stem cells to be used for substitutive and regenerative cell therapiesS.R.H. and P.T.R. are funded by the Government of Spain (MINECO, RYC-2016- 21395 and SAF2015–71589-P [S.R.H.]; PEJ-2014-A-31985 and SAF2015–71589- P [P.T.R.]). GGS is supported by a grant from the Ministry of Health of the Federal Republic of Germany (FKZ2518FSB403)

Therapeutic strategies for the treatment of Spinal Muscular Atrophy (SMA) disease

Spinal Muscular Atrophy (SMA) is a progressive neurodegenerative disorder characterised by the loss of upper and/or lower motor neurons. SMA is the leading genetic cause of infant mortality with an incidence of 1 in 6000 live births and a carrier frequency of about 1 in 50. Different types of disease (from SMAI to SMAV) have been described based on clinical severity and age of onset. The SMA-determining gene, Survival of Motor Neurons (SMN), is part of a 500 kb-inverted duplication on chromosome 5q13. Within the duplicated genes SMN1 and SMN2 can be found. Most (95%) SMA patients have deletions or conversion events of SMN1. The SMN2 gene primarily produces a transcript which lacks exon 7 and of which only 10-20% of its protein is functional. Although a variety of therapeutic trials are ongoing, only life-prolonging treatments are being developed. The knowledge gained regarding the pathogenesis of SMA remains limited, because the precise function of SMN is not yet known. Furthermore, it is not quite clear why motor neurons of the patients are the only cell type for which SMN expression level are unadequate for their normal activity, even if the affected genes have “housekeeping” functions. Both pharmacological or genetic approaches have been conducted for the therapy of SMA. Moreover, stem cells provide a further aspect to be analysed. In fact, the genetic modification of a small number of stem cells could give rise to a dividing population of therapeutic cells. These innovative approaches when united could be usefully adopted to replace lost cells and at the same time protect surviving motor neurons in SMA patients

What is better for you is better for the Environment?

evidenze empiriche dell'impatto salutistico ed ambientale degli aliment

Cellular genetic therapy

Cellular genetic therapy is the ultimate frontier for those pathologies that are consequent to a specific nonfunctional cellular type. A viable cure for there kinds of diseases is the replacement of sick cells with healthy ones, which can be obtained from the same patient or a different donor. In fact, structures can be corrected and strengthened with the introduction of undifferentiated cells within specific target tissues, where they will specialize into the desired cellular types. Furthermore, consequent to the recent results obtained with the transdifferentiation experiments, a process that allows the in vitro differentiation of embryonic and adult stem cells, it has also became clear that many advantages may be obtained from the use of stem cells to produce drugs, vaccines, and therapeutic molecules. Since stem cells can sustain lineage potentials, the capacity for differentiation, and better tolerance for the introduction of exogenous genes, they are also considered as feasible therapeutic vehicles for gene therapy. In fact, it is strongly believed that the combination of cellular genetic and gene therapy approaches will definitely allow the development of new therapeutic strategies as well as the production of totipotent cell lines to be used as experimental models for the cure of genetic disorders

Progress in Gene Therapy Research (Horizons in Cancer Research; Vol. 20)

The ideal aim of gene therapy approach for the treatment of inherited disorders should involve a lasting and tissue specific expression of the functional gene. Besides, in gene therapy any technology used should fulfil several requirements, including safety, simplicity of use, cost effectiveness and amenability to industrial scale. To this end an in situ permanent correction of the defective endogenous gene (gene targeting approach) is preferable to a transient addition of exogenous non-integrating vectors expressing the wild type version of the gene or its cDNA (gene augmentation approach). In fact, the site-specific modification leads to a long term and genetically inheritable expression of the corrected gene, regardless its size. Moreover, in terms of time and space an in situ correction approach allows physiological expression of the targeted gene, since it remains under cell-specific regulatory regions. Gene targeting therapeutic approaches can be broadly divided into viral and non-viral gene transfer technology. Viral vectors take the advantage on the easy integration of the gene of interest into the host and high probability of its long–term expression but they are plagued by safety concerns. although less efficient at introducing and maintaining foreign gene expression Non-viral vectors (naked DNA fragments and plasmid DNA), have the profound advantage of being non-pathogenic and non-immunogenic. With reference to the naked DNA approach, the recent availability of better delivery methods (e.g. electroporation and microinjection) has made the non-viral gene transfer an increasingly more important and viable method for gene therapy. Since the viral based approaches are being investigated as well, the current chapter focuses on the use of naked DNA for the production of targeted alterations in the genome of mammalian cells. In particular it will review the most representative experimental strategies recently exploited, trying to consider advantages and down sides of techniques such as the non viral Sleeping Beauty transposon system (SB), the Short Fragment Homologous Recombination (SFHR), the chimeric RNA/DNA Oligonucleotides (RDO), the small interfering RNA (siRNA) and the homologous recombination dependent Gene Targeting (hrdGT)