Effective high-throughput isolation of enriched platelets and circulating pro-angiogenic cells to accelerate skin-wound healing.

Delayed wound healing and chronic skin lesions represent a major health problem. Over the past years, growth factors mediated by platelet-rich plasma (PRP) and cell-based therapies were developed as effective and affordable treatment able to improve wound healing capacity. We have advanced existing concepts to develop a highly efficient high-throughput protocol with proven application for the isolation of PRP and pro-angiogenic cells (AngioPRP). This protocol outlines the effectiveness of AngioPRP in promoting the critical healing process including wound closure, re-epithelialization, granulation tissue growth, and blood vessel regeneration. We coupled this effect with normalization of mechanical properties of rescued mouse wounds, which is sustained by a correct arrangement of elastin and collagen fibers. Proteomic analysis of treated wounds demonstrated a fingerprint of AngioPRP based on the up-regulation of detoxification pathway of glutathione metabolism, correlated to a decrease in inflammatory response. Overall, these results have enabled us to provide a framework for how AngioPRP supports wound healing, opening avenues for further clinical advances.

Autologous intramuscular transplantation of engineered satellite cells induces exosome-mediated systemic expression of Fukutin-related protein and rescues disease phenotype in a murine model of limb-girdle muscular dystrophy type 2I.

α-Dystroglycanopathies are a group of muscular dystrophies characterized by α-DG hypoglycosylation and reduced extracellular ligand-binding affinity. Among other genes involved in the α-DG glycosylation process, fukutin related protein (FKRP) gene mutations generate a wide range of pathologies from mild limb girdle muscular dystrophy 2I (LGMD2I), severe congenital muscular dystrophy 1C (MDC1C), to Walker-Warburg Syndrome and Muscle-Eye-Brain disease. FKRP gene encodes for a glycosyltransferase that in vivo transfers a ribitol phosphate group from a CDP -ribitol present in muscles to α-DG, while in vitro it can be secreted as monomer of 60kDa. Consistently, new evidences reported glycosyltransferases in the blood, freely circulating or wrapped within vesicles. Although the physiological function of blood stream glycosyltransferases remains unclear, they are likely released from blood borne or distant cells. Thus, we hypothesized that freely or wrapped FKRP might circulate as an extracellular glycosyltransferase, able to exert a "glycan remodelling" process, even at distal compartments. Interestingly, we firstly demonstrated a successful transduction of MDC1C blood-derived CD133+ cells and FKRP L276IKI mouse derived satellite cells by a lentiviral vector expressing the wild-type of human FKRP gene. Moreover, we showed that LV-FKRP cells were driven to release exosomes carrying FKRP. Similarly, we observed the presence of FKRP positive exosomes in the plasma of FKRP L276IKI mice intramuscularly injected with engineered satellite cells. The distribution of FKRP protein boosted by exosomes determined its restoration within muscle tissues, an overall recovery of α-DG glycosylation and improved muscle strength, suggesting a systemic supply of FKRP protein acting as glycosyltransferase.

Adaptive Immune Response Impairs the Efficacy of Autologous Transplantation of Engineered Stem Cells in Dystrophic Dogs.

Duchenne muscular dystrophy is the most common genetic muscular dystrophy. It is caused by mutations in the dystrophin gene, leading to absence of muscular dystrophin and to progressive degeneration of skeletal muscle. We have demonstrated that the exon skipping method safely and efficiently brings to the expression of a functional dystrophin in dystrophic CD133+ cells injected scid/mdx mice. Golden Retriever muscular dystrophic (GRMD) dogs represent the best preclinical model of Duchenne muscular dystrophy, mimicking the human pathology in genotypic and phenotypic aspects. Here, we assess the capacity of intra-arterial delivered autologous engineered canine CD133+ cells of restoring dystrophin expression in Golden Retriever muscular dystrophy. This is the first demonstration of five-year follow up study, showing initial clinical amelioration followed by stabilization in mild and severe affected Golden Retriever muscular dystrophy dogs. The occurrence of T-cell response in three Golden Retriever muscular dystrophy dogs, consistent with a memory response boosted by the exon skipped-dystrophin protein, suggests an adaptive immune response against dystrophin.

Pericytes of human skeletal muscle are myogenic precursors distinct from satellite cells.

Cells derived from blood vessels of human skeletal muscle can regenerate skeletal muscle, similarly to embryonic mesoangioblasts. However, adult cells do not express endothelial markers, but instead express markers of pericytes, such as NG2 proteoglycan and alkaline phosphatase (ALP), and can be prospectively isolated from freshly dissociated ALP(+) cells. Unlike canonical myogenic precursors (satellite cells), pericyte-derived cells express myogenic markers only in differentiated myotubes, which they form spontaneously with high efficiency. When transplanted into severe combined immune deficient-X-linked, mouse muscular dystrophy (scid-mdx) mice, pericyte-derived cells colonize host muscle and generate numerous fibres expressing human dystrophin. Similar cells isolated from Duchenne patients, and engineered to express human mini-dystrophin, also give rise to many dystrophin-positive fibres in vivo. These data show that myogenic precursors, distinct from satellite cells, are associated with microvascular walls in the human skeletal muscle, may represent a correlate of embryonic 'mesoangioblasts' present after birth and may be a promising candidate for future cell-therapy protocols in patients.

Flvcr1a deficiency promotes heme-based energy metabolism dysfunction in skeletal muscle.

The definition of cell metabolic profile is essential to ensure skeletal muscle fiber heterogeneity and to achieve a proper equilibrium between the self-renewal and commitment of satellite stem cells. Heme sustains several biological functions, including processes profoundly implicated with cell metabolism. The skeletal muscle is a significant heme-producing body compartment, but the consequences of impaired heme homeostasis on this tissue have been poorly investigated. Here, we generate a skeletal-muscle-specific feline leukemia virus subgroup C receptor 1a (FLVCR1a) knockout mouse model and show that, by sustaining heme synthesis, FLVCR1a contributes to determine the energy phenotype in skeletal muscle cells and to modulate satellite cell differentiation and muscle regeneration.

Absence of T and B lymphocytes modulates dystrophic features in dysferlin deficient animal model.

Dysferlin mutations cause muscular dystrophy (dysferlinopathy) characterized by adult onset muscle weakness, high serum creatine kinase levels, attenuation of muscle regeneration and a prominent inflammatory infiltrate. In order to verify the role of lymphocytes and immune cells on this disease, we generated the Scid/A/J transgenic mice and compared these animals with the age-matched A/J mice. The absence of T and B lymphocytes in this animal model of dysferlinopathy resulted in an improvement of the muscle regeneration. Scid/A/J mice showed increased specific force in the myosin heavy chain 2A-expressing fibers of the diaphragm and abdominal muscles. Moreover, a partial reduction in complement deposition was observed together with a diminution in pro-inflammatory M1 macrophages. Consistent with this model, T and B lymphocytes seem to have a role in the muscle damaging immune response. The knowledge of the involvement of immune system in the development of dysferlinopathies could represent an important tool for their rescuing. By studying Scid/blAJ mice, we showed that it could be possible to modulate the pathological symptoms of these diseases by interfering with different components of the immune system.

CD133(+) Cells for the Treatment of Degenerative Diseases: Update and Perspectives.

Stem cells are used in cell therapy for degenerative disorders. The main advantage of stem cells is that they can replenish their numbers for long periods through cell division and produce a progeny that can differentiate into multiple cell lineages with specific functions. CD133 is a member of a novel family of cell surface glycoproteins. The expression of human CD133 (AC133 antigen) was originally described in the hematopoietic CD34(+) stem cells, but now it becomes more and more evident that CD133 is a marker of stem and progenitor cell populations originating from various tissues and organs. The main objective of this chapter is to describe the potential sources of CD133(+) stem cells that harbor the ability to engraft, proliferate, and differentiate into functional cells. The characterization of such CD133(+) stem cells unlocks new opportunities in the treatment of degenerative diseases such as Duchenne muscular dystrophy.

Reprogramming of dermal fibroblasts from a Duchenne muscular dystrophy patient carrying a deletion of exons 45-50 into an induced pluripotent stem cell line (CCMi005-A).

Duchenne muscular dystrophy (DMD) is an X-linked syndrome that affects skeletal and cardiac muscle and is caused by mutation of the dystrophin gene. Induced pluripotent stem cells (iPSCs) were generated from dermal fibroblasts by electroporation with episomal vectors containing the reprogramming factors (OCT4, SOX2, LIN28, KLF4, and l-MYC). The donor carried an out-of-frame deletion of exons 45-50 of the dystrophin gene. The established iPSC line exhibited normal morphology, expressed pluripotency markers, had normal karyotype and possessed trilineage differentiation potential.

Defective dystrophic thymus determines degenerative changes in skeletal muscle.

In Duchenne muscular dystrophy (DMD), sarcolemma fragility and myofiber necrosis produce cellular debris that attract inflammatory cells. Macrophages and T-lymphocytes infiltrate muscles in response to damage-associated molecular pattern signalling and the release of TNF-α, TGF-ß and interleukins prevent skeletal muscle improvement from the inflammation. This immunological scenario was extended by the discovery of a specific response to muscle antigens and a role for regulatory T cells (Tregs) in muscle regeneration. Normally, autoimmunity is avoided by autoreactive T-lymphocyte deletion within thymus, while in the periphery Tregs monitor effector T-cells escaping from central regulatory control. Here, we report impairment of thymus architecture of mdx mice together with decreased expression of ghrelin, autophagy dysfunction and AIRE down-regulation. Transplantation of dystrophic thymus in recipient nude mice determine the up-regulation of inflammatory/fibrotic markers, marked metabolic breakdown that leads to muscle atrophy and loss of force. These results indicate that involution of dystrophic thymus exacerbates muscular dystrophy by altering central immune tolerance.

Treatment with ROS detoxifying gold quantum clusters alleviates the functional decline in a mouse model of Friedreich ataxia.

Friedreich ataxia (FRDA) is caused by the reduced expression of the mitochondrial protein frataxin (FXN) due to an intronic GAA trinucleotide repeat expansion in the FXN gene. Although FRDA has no cure and few treatment options, there is research dedicated to finding an agent that can curb disease progression and address symptoms as neurobehavioral deficits, muscle endurance, and heart contractile dysfunctions. Because oxidative stress and mitochondrial dysfunctions are implicated in FRDA, we demonstrated the systemic delivery of catalysts activity of gold cluster superstructures (Au8-pXs) to improve cell response to mitochondrial reactive oxygen species and thereby alleviate FRDA-related pathology in mesenchymal stem cells from patients with FRDA. We also found that systemic injection of Au8-pXs ameliorated motor function and cardiac contractility of YG8sR mouse model that recapitulates the FRDA phenotype. These effects were associated to long-term improvement of mitochondrial functions and antioxidant cell responses. We related these events to an increased expression of frataxin, which was sustained by reduced autophagy. Overall, these results encourage further optimization of Au8-pXs in experimental clinical strategies for the treatment of FRDA.

Expression of parathyroid-specific genes in vascular endothelial progenitors of normal and tumoral parathyroid glands.

Parathyroid tissue is able to spontaneously induce angiogenesis, proliferate, and secrete parathyroid hormone when autotransplanted in patients undergoing total parathyroidectomy. Angiogenesis is also involved in parathyroid tumorigenesis. Here we investigated the anatomical and molecular relationship between endothelial and parathyroid cells within human parathyroid glands. Immunohistochemistry for CD34 antigen identified two subpopulations in normal and tumoral parathyroid glands: one constituted by cells lining small vessels that displayed endothelial antigens (factor VIII, isolectin, laminin, CD146) and the other constituted of single cells scattered throughout the parenchyma that did not express endothelial markers. These parathyroid-derived CD34(+) cells were negative for the hematopoietic and mesenchymal markers CD45, Thy-1/CD90, CD105, and CD117/c-kit; however, a subset of CD34(+) cells co-expressed the parathyroid specific genes glial cell missing B, parathyroid hormone, and calcium sensing receptor. When cultured, these cells released significant amount of parathyroid hormone. Parathyroid-derived CD34(+) cells, but not CD34(-) cells, proliferated slowly and differentiated into mature endothelial cells. CD34(+) cells from parathyroid tumors differed from those derived from normal parathyroid glands as: 1) they were more abundant and mainly scattered throughout the parenchyma; 2) they rarely co-expressed CD146; and 3) a fraction co-expressed nestin. In conclusion, we identified cells expressing endothelial and parathyroid markers in human adult parathyroid glands. These parathyroid/endothelial cells were more abundant and less committed in parathyroid tumors compared with normal glands, showing features of endothelial progenitors, which suggests that they might be involved in parathyroid tumorigenesis.

In vivo myogenic potential of human CD133+ muscle-derived stem cells: a quantitative study.

In recent years, numerous reports have identified in mouse different sources of myogenic cells distinct from satellite cells that exhibited a variable myogenic potential in vivo. Myogenic stem cells have also been described in humans, although their regenerative potential has rarely been quantified. In this study, we have investigated the myogenic potential of human muscle-derived cells based on the expression of the stem cell marker CD133 as compared to bona fide satellite cells already used in clinical trials. The efficiency of these cells to participate in muscle regeneration and contribute to the renewal of the satellite cell pool, when injected intramuscularly, has been evaluated in the Rag2(-/-) gammaC(-/-) C5(-/-) mouse in which muscle degeneration is induced by cryoinjury. We demonstrate that human muscle-derived CD133+ cells showed a much greater regenerative capacity when compared to human myoblasts. The number of fibers expressing human proteins and the number of human cells in a satellite cell position are all dramatically increased when compared to those observed after injection of human myoblasts. In addition, CD133+/CD34+ cells exhibited a better dispersion in the host muscle when compared to human myoblasts. We propose that muscle-derived CD133+ cells could be an attractive candidate for cellular therapy.

Effects of rituximab in two patients with dysferlin-deficient muscular dystrophy.

BACKGROUND: The administration of rituximab (RTX) in vivo results in B-cell depletion, but evidence for multiple mechanisms of action have been reported. Surprisingly, B cell depletion produced a response in patients with polymyositis, which is characterized as a T cell-mediated autoimmune disorder with biopsy findings similar to Miyoshi myopathy (MM). Indeed, in dysferlinopathies, there is evidence of immune system involvement including the presence of muscle inflammation and a down regulation of the complement inhibitory factor, CD55. METHODS: Two patients were treated with four weekly infusions of RTX 375 mg/m2. To measure the improvement in muscle strength after treatment, the isometric hand grip maximal voluntary contraction (MVC) was measured by load cell four times during treatment, and again after one year. In order to assess the reproducibility of our grip assessment, we determined the hand MVC analysis in 16 healthy subjects. Moreover, we measured the number of B cells present in patients by flow cytometric analysis during the course of treatment. RESULTS: The analysis of B cell number during the course of treatment showed that CD20- and CD19-positive cells were depleted to 0-0.01%. The decrease in B cells was followed by an improvement in the mobility of the pelvic and shoulder girdles as shown by the MRC%. The MVC values of both patients began at values lower than normal whereas during treatment patients had improved percentage of muscle strength. The strength peak in both patients coincided with the minimum B cell values. There were no severe adverse events associated with an infusion of RTX. CONCLUSION: We consider the increase in muscle strength observed in both treated patients to be a consequence of their treatment with RTX. To our knowledge, these are the first cases of increased muscle strength in patients with MM. Furthermore, the results of this study indicate that B cell depletion with RTX may be useful in the treatment of patients affected by MM, suggesting a possible role for B cells in the pathophysiology of this muscle disorder.

Stem cell tracking by nanotechnologies.

Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. The beneficial effects of stem cell therapy depend also by the development of new approachs for the track of stem cells in living subjects over time after transplantation. Recent developments in the use of nanotechnologies have contributed to advance of the high-resolution in vivo imaging methods, including positron emission tomography (PET), single-photon emission tomography (SPECT), magnetic resonance (MR) imaging, and X-Ray computed microtomography (microCT). This review examines the use of nanotechnologies for stem cell tracking.

Generation of the Becker muscular dystrophy patient derived induced pluripotent stem cell line carrying the DMD splicing mutation c.1705-8 T>C.

Becker Muscular dystrophy (BMD) is an X-linked syndrome characterized by progressive muscle weakness. BMD is generally less severe than Duchenne Muscular Dystrophy. BMD is caused by mutations in the dystrophin gene that normally give rise to the production of a truncated but partially functional dystrophin protein. We generated an induced pluripotent cell line from dermal fibroblasts of a BMD patient carrying a splice mutation in the dystrophin gene (c.1705-8 T>C). The iPSC cell-line displayed the characteristic pluripotent-like morphology, expressed pluripotency markers, differentiated into cells of the three germ layers and had a normal karyotype.

Interstitial Cell Remodeling Promotes Aberrant Adipogenesis in Dystrophic Muscles.

Fibrosis and fat replacement in skeletal muscle are major complications that lead to a loss of mobility in chronic muscle disorders, such as muscular dystrophy. However, the in vivo properties of adipogenic stem and precursor cells remain unclear, mainly due to the high cell heterogeneity in skeletal muscles. Here, we use single-cell RNA sequencing to decomplexify interstitial cell populations in healthy and dystrophic skeletal muscles. We identify an interstitial CD142-positive cell population in mice and humans that is responsible for the inhibition of adipogenesis through GDF10 secretion. Furthermore, we show that the interstitial cell composition is completely altered in muscular dystrophy, with a near absence of CD142-positive cells. The identification of these adipo-regulatory cells in the skeletal muscle aids our understanding of the aberrant fat deposition in muscular dystrophy, paving the way for treatments that could counteract degeneration in patients with muscular dystrophy.

Blockade of IGF2R improves muscle regeneration and ameliorates Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a debilitating fatal X-linked muscle disorder. Recent findings indicate that IGFs play a central role in skeletal muscle regeneration and development. Among IGFs, insulinlike growth factor 2 (IGF2) is a key regulator of cell growth, survival, migration and differentiation. The type 2 IGF receptor (IGF2R) modulates circulating and tissue levels of IGF2 by targeting it to lysosomes for degradation. We found that IGF2R and the store-operated Ca2+ channel CD20 share a common hydrophobic binding motif that stabilizes their association. Silencing CD20 decreased myoblast differentiation, whereas blockade of IGF2R increased proliferation and differentiation in myoblasts via the calmodulin/calcineurin/NFAT pathway. Remarkably, anti-IGF2R induced CD20 phosphorylation, leading to the activation of sarcoplasmic/endoplasmic reticulum Ca2+ -ATPase (SERCA) and removal of intracellular Ca2+ . Interestingly, we found that IGF2R expression was increased in dystrophic skeletal muscle of human DMD patients and mdx mice. Blockade of IGF2R by neutralizing antibodies stimulated muscle regeneration, induced force recovery and normalized capillary architecture in dystrophic mdx mice representing an encouraging starting point for the development of new biological therapies for DMD.

Identification of a putative pathway for the muscle homing of stem cells in a muscular dystrophy model.

Attempts to repair muscle damage in Duchenne muscular dystrophy (DMD) by transplanting skeletal myoblasts directly into muscles are faced with the problem of the limited migration of these cells in the muscles. The delivery of myogenic stem cells to the sites of muscle lesions via the systemic circulation is a potential alternative approach to treat this disease. Muscle-derived stem cells (MDSCs) were obtained by a MACS(R) multisort method. Clones of MDSCs, which were Sca-1+/CD34-/L-selectin+, were found to adhere firmly to the endothelium of mdx dystrophic muscles after i.v. or i.m. injections. The subpopulation of Sca-1+/CD34- MDSCs expressing L-selectin was called homing MDSCs (HMDSCs). Treatment of HMDSCs with antibodies against L-selectin prevented adhesion to the muscle endothelium. Importantly, we found that vascular endothelium from striate muscle of young mdx mice expresses mucosal addressin cell adhesion molecule-1 (MAdCAM-1), a ligand for L-selectin. Our results showed for the first time that the expression of the adhesion molecule L-selectin is important for muscle homing of MDSCs. This discovery will aid in the improvement of a potential therapy for muscular dystrophy based on the systemic delivery of MDSCs.

Effect of human skin-derived stem cells on vessel architecture, tumor growth, and tumor invasion in brain tumor animal models.

Glioblastomas represent an important cause of cancer-related mortality with poor survival. Despite many advances, the mean survival time has not significantly improved in the last decades. New experimental approaches have shown tumor regression after the grafting of neural stem cells and human mesenchymal stem cells into experimental intracranial gliomas of adult rodents. However, the cell source seems to be an important limitation for autologous transplantation in glioblastoma. In the present study, we evaluated the tumor targeting and antitumor activity of human skin-derived stem cells (hSDSCs) in human brain tumor models. The hSDSCs exhibit tumor targeting characteristics in vivo when injected into the controlateral hemisphere or into the tail vein of mice. When implanted directly into glioblastomas, hSDSCs distributed themselves extensively throughout the tumor mass, reduced tumor vessel density, and decreased angiogenic sprouts. In addition, transplanted hSDSCs differentiate into pericyte cell and release high amounts of human transforming growth factor-beta1 with low expression of vascular endothelial growth factor, which may contribute to the decreased tumor cell invasion and number of tumor vessels. In long-term experiments, the hSDSCs were also able to significantly inhibit tumor growth and to prolong animal survival. Similar behavior was seen when hSDSCs were implanted into two different tumor models, the chicken embryo experimental glioma model and the transgenic Tyrp1-Tag mice. Taken together, these data validate the use of hSDSCs for targeting human brain tumors. They may represent therapeutically effective cells for the treatment of intracranial tumors after autologous transplantation.

Preliminary Evidences of Safety and Efficacy of Flavonoids- and Omega 3-Based Compound for Muscular Dystrophies Treatment: A Randomized Double-Blind Placebo Controlled Pilot Clinical Trial.

Background: Nutritional compounds can exert both anti-inflammatory and anti-oxidant effects. Since these events exacerbate the pathophysiology of muscular dystrophies, we investigated nutraceutical supplementation as an adjuvant therapy in dystrophic patients, to low costs and easy route of administration. Moreover, this treatment could represent an alternative therapeutic strategy for dystrophic patients who do not respond to corticosteroid treatment. Objective: A 24 weeks randomized double-blind placebo-controlled clinical study was aimed at evaluating the safety and efficacy of daily oral administration of flavonoids- and omega3-based natural supplement (FLAVOMEGA) in patients affected by muscular dystrophy with recognized muscle inflammation. Design: We screened 60 patients diagnosed for Duchenne (DMD), Facioscapulohumeral (FSHD), and Limb Girdle Muscular Dystrophy (LGMD). Using a computer-generated random allocation sequence, we stratified patients in a 2:1:1 ratio (DMD:FSHD:LGMD) to one of two treatment groups: continuous FLAVOMEGA, continuous placebo. Of 29 patients included, only 24 completed the study: 15 were given FLAVOMEGA, 14 placebo. Results: FLAVOMEGA was well tolerated with no reported adverse events. Significant treatment differences in the change from baseline in 6 min walk distance (6MWD; secondary efficacy endpoint) (P = 0.033) and in isokinetic knee extension (P = 0.039) (primary efficacy endpoint) were observed in LGMD and FSHD subjects. Serum CK levels (secondary efficacy endpoint) decreased in all FLAVOMEGA treated groups with significant difference in DMD subjects (P = 0.039). Conclusions: Although the small number of patients and the wide range of disease severity among patients reduced statistical significance, we obtained an optimal profile of safety and tolerability for the compound, showing valuable data of efficacy in primary and secondary endpoints. Trial registration number: NCT03317171 Retrospectively registered 25/10/2017.