Cell Therapy For Muscular Dystrophies Research Articles

Cell-mediated exon skipping normalizes dystrophin expression and muscle function in a new mouse model ofDuchenne Muscular Dystrophy.

Cell therapy for muscular dystrophy has met with limited success, mainly due to the poor engraftment of donor cells, especially in fibrotic muscle at an advanced stage of the disease. We developed a cell-mediated exon skipping that exploits the multinucleated nature of myofibers to achieve cross-correction of resident, dystrophic nuclei by the U7 small nuclear RNA engineered to skip exon 51 of the dystrophin gene. We observed that co-culture of genetically corrected human DMD myogenic cells (but not of WT cells) with their dystrophic counterparts at a ratio of either 1:10 or 1:30 leads to dystrophin production at a level several folds higher than what predicted by simple dilution. This is due to diffusion of U7 snRNA to neighbouring dystrophic resident nuclei. When transplanted into NSG-mdx-Δ51mice carrying a mutation of exon 51, genetically corrected human myogenic cells produce dystrophin at much higher level than WT cells, well in the therapeutic range, and lead to force recovery even with an engraftment of only 3-5%. This level of dystrophin production is an important step towards clinical efficacy for cell therapy.

Mesoangioblasts at 20: From the embryonic aorta to the patient bed.

In 2002 we published an article describing a population of vessel-associated progenitors that we termed mesoangioblasts (MABs). During the past decade evidence had accumulated that during muscle development and regeneration things may be more complex than a simple sequence of binary choices (e.g., dorsal vs. ventral somite). LacZ expressing fibroblasts could fuse with unlabelled myoblasts but not among themselves or with other cell types. Bone marrow derived, circulating progenitors were able to participate in muscle regeneration, though in very small percentage. Searching for the embryonic origin of these progenitors, we identified them as originating at least in part from the embryonic aorta and, at later stages, from the microvasculature of skeletal muscle. While continuing to investigate origin and fate of MABs, the fact that they could be expanded in vitro (also from human muscle) and cross the vessel wall, suggested a protocol for the cell therapy of muscular dystrophies. We tested this protocol in mice and dogs before proceeding to the first clinical trial on Duchenne Muscular Dystrophy patients that showed safety but minimal efficacy. In the last years, we have worked to overcome the problem of low engraftment and tried to understand their role as auxiliary myogenic progenitors during development and regeneration.

Physical optimization of cell proliferation and differentiation using spinner flask and microcarriers

The traditional breeding industry has been increasingly saturated and caused environmental pollution, disease transmission, excessive resource use, and methane emission; however, it still cannot meet the needs of the growing population. To explore other alternatives, researchers focused on cell agriculture and cell-based meat, especially large-scale cell culture. As a prerequisite for production, large-scale culture technology has become an important bottleneck restricting cell-based meat industrialization. In this study, the single-factor variable method was adopted to examine the influence of Cytodex1 microcarrier pretreatment, spinner flask reaction vessel, cell culture medium, serum and cell incubation, and other influencing factors on large-scale cell cultures to identify the optimization parameters suitable for 3D culture environment. Collagen and 3D culture were also prospectively explored to promote myogenesis and cultivate tissue-like muscle fibers that contract spontaneously. This research lays a theoretical foundation and an exploratory practice for large-scale cell cultures and provides a study reference for the microenvironment of myoblast culture in vitro, a feasible direction for the cell therapy of muscular dystrophy, and prerequisites for the industrialized manufacturing of cell-based meat.Graphical Graphical summary: Research on large-scale myoblast culture using spinner flasks and microcarriers. For cell culture, the microcarriers were pretreated with UV and collagen. Cell seeding condition, spinner flask speed, resting time, and spinner flask culture microenvironment were then optimized. Finally, two culture systems were prepared: a culture system based on large-scale cell expansion and a culture system for myogenesis promotion and differentiation

Stem cell therapy for muscular dystrophies.

Muscular dystrophies are a heterogeneous group of genetic diseases, characterized by progressive degeneration of skeletal and cardiac muscle. Despite the intense investigation of different therapeutic options, a definitive treatment has not been developed for this debilitating class of pathologies. Cell-based therapies in muscular dystrophies have been pursued experimentally for the last three decades. Several cell types with different characteristics and tissues of origin, including myogenic stem and progenitor cells, stromal cells, and pluripotent stem cells, have been investigated over the years and have recently entered in the clinical arena with mixed results. In this Review, we do a roundup of the past attempts and describe the updated status of cell-based therapies aimed at counteracting the skeletal and cardiac myopathy present in dystrophic patients. We present current challenges, summarize recent progress, and make recommendations for future research and clinical trials.

IPS細胞由来骨格筋幹細胞を用いた筋ジストロフィーに対する細胞移植治療の開発

iPS細胞由来骨格筋幹細胞を用いた筋ジストロフィーに対する細胞移植治療の開発

Gene and Cell Therapy for Muscular Dystrophies: Are We Getting There?

In the last few years, significant advances have occurred in the preclinical and clinical work toward gene and cell therapy for muscular dystrophy. At the time of this writing, several trials are ongoing and more are expected to start. It is thus a time of expectation, even though many hurdles remain and it is unclear whether they will be overcome with current strategies or if further improvements will be necessary.

Premyogenic progenitors derived from human pluripotent stem cells expand in floating culture and differentiate into transplantable myogenic progenitors

Human induced pluripotent stem cells (hiPSCs) are a potential source for cell therapy of Duchenne muscular dystrophy. To reliably obtain skeletal muscle progenitors from hiPSCs, we treated hiPS cells with a Wnt activator, CHIR-99021 and a BMP receptor inhibitor, LDN-193189, and then induced skeletal muscle cells using a previously reported sphere-based culture. This protocol greatly improved sphere formation efficiency and stably induced the differentiation of myogenic cells from hiPS cells generated from both healthy donors and a patient with congenital myasthenic syndrome. hiPSC-derived myogenic progenitors were enriched in the CD57(−) CD108(−) CD271(+) ERBB3(+) cell fraction, and their differentiation was greatly promoted by TGF-β inhibitors. TGF-β inhibitors down-regulated the NFIX transcription factor, and NFIX short hairpin RNA (shRNA) improved the differentiation of iPS cell-derived myogenic progenitors. These results suggest that NFIX inhibited differentiation of myogenic progenitors. hiPSC-derived myogenic cells differentiated into myofibers in muscles of NSG-mdx4Cv mice after direct transplantation. Our results indicate that our new muscle induction protocol is useful for cell therapy of muscular dystrophies.

The weak combined magnetic field, tuned to ion parametric resonance for Ca2+, stimulates dystrophin synthesis in the skeletal muscles of mdx mice subjected to cell therapy

The possibility of using bone marrow stem cells for treatment of Duchenne muscular dystrophy is intensely studied. Mdx mice are the most widely used laboratory model of Duchenne muscular dystrophy. One approach of cell therapy of muscular dystrophy is substitution of bone marrow in mdx mice after their X-ray irradiation. However, this method does not allow one to increase significantly dystrophin synthesis in muscular fibers of mdx mice. To improve the effect of transplanted cells on muscle regeneration, we additionally treated mdx mice subjected to transplantation of bone marrow cells with a weak combined magnetic field tuned to ion parametric resonance for Ca2+ (Ca2+-CMF). We found that, in irradiated chimeric 3 and 5 Gy mdx mice, additional treatment with Ca2+-CMF for 1 month resulted in significant increases in the portions of dystrophin-positive muscle fibers, by 15.8 and 18.3%, respectively, as compared to the control groups. Furthermore, the share of muscle fibers without centrally located nuclei also increased. We suggest that the magnetic field with these parameters may stimulate functioning of nuclei of donor cells, which were incorporated into muscle fibers.

Not All Pericytes Are Born Equal: Pericytes from Human Adult Tissues Present Different Differentiation Properties.

Pericytes (PCs) have been recognized for a long time only as structural cells of the blood vessels. The identification of tight contacts with endothelial cells and the ability to interact with surrounding cells through paracrine signaling revealed additional functions of PCs in maintaining the homeostasis of the perivascular environment. PCs got the front page, in the late 1990s, after the identification and characterization of a new embryonic cell population, the mesoangioblasts, from which PCs present in the adult organism are thought to derive. From these studies, it was clear that PCs were also endowed with multipotent mesodermal abilities. Furthermore, their ability to cross the vascular wall and to reconstitute skeletal muscle tissue after systemic injection opened the way to a number of studies aimed to develop therapeutic protocols for a cell therapy of muscular dystrophy. This has resulted in a major effort to characterize pericytic cell populations from skeletal muscle and other adult tissues. Additional studies also addressed their relationship with other cells of the perivascular compartment and with mesenchymal stem cells. These data have provided initial evidence that PCs from different adult tissues might be endowed with distinctive differentiation abilities. This would suggest that the multipotent mesenchymal ability of PCs might be restrained within different tissues, likely depending on the specific cell renewal and repair requirements of each tissue. This review presents current knowledge on human PCs and highlights recent data on the differentiation properties of PCs isolated from different adult tissues.

404. Development of Human Artificial Chromosomes for Gene Cell Therapy of Muscular Dystrophies

Muscular dystrophies are clinically heterogeneous group of muscle diseases related to different genes defects. The results of defects impair myogenic differentiation and histophysiology of skeletal muscles. One of major forms of disease – limb-girdle muscular dystrophy 2B (LGMD2B), caused by dysferlin gene mutations. Both big size of gene and wide variety of mutations complicate development of genetically engineered drugs. Human artificial chromosomes (HAC) could be used as alternative approach. This vector can contain unlimitedly large DNA region for transfer, is retained during cell division, and does not have carcinogenic and immunogenic properties.HAC matrix was developed earlier by Larionov V. et al. (http://www.ncbi.nlm.nih.gov/pubmed/22123967). Optimized DYSF gene sequence (optDYSF) from pAd/CMV/V5-DEST vector (kindly provided by A.A. Rizvanov) was transferred into backbone vector also containing loxP sites for further transfer into HAC. Transfer correctness confirmed by sequencing. After that Chinese hamster ovary cells carrying HAC were transfected by backbone vector containing optDYSF. Selection performed in HAT medium. 7 clones were selected and analyzed at day 10. Expression of optDYSF observed in all obtained clones. Episomal HAC localization determined using fluorescent hybridization in sity by colocalization of label at optDYSF and a-satellite DNA. Episomal localization of HAC determined only in 2 clones from 7. Dysferlin production observed in all clones.On other hand described vector requires somatic myogenic vector cell. Human myoblasts could be successfully used for this purpose. The major source of myoblasts – skeletal muscle tissue is not optimal due to limited proliferative potential, especially in patients with muscular dystrophies. Our team revealed presence of myoblasts in gingival mucosa specimens and developed new method of myoblasts obtainment from it. Primary cultures of multipotent mesenchymal stromal cells (MSC) were derived from gingiva biopsy samples. The cells expressed typical mesenchymal stem cells markers and had ability for 3-way differentiation. Myogenic induction of gingiva derived MSC in culture was demonstrated. Gingiva derived MSC are capable to express markers of myogenic differentiation (skeletal actin, sceletal myosin, MyoD1) and form multicellular elongated fibers – myotubes. Ability of gingiva derived MSC cultures to differentiate in myogenic direction was preserved during up to 10th passage. Such features make this cell source attractive for using in treatment of inherited muscular degenerative diseases.In our future research we are planning to transfer HAC containing optDYSF gene into clonogenic gingiva derived MSC using microcell-mediated chromosome transfer. This method could be used for further development of gene cell therapy of LGMD2B.

Concise review: mesoangioblast and mesenchymal stem cell therapy for muscular dystrophy: progress, challenges, and future directions.

Mesenchymal stem cells (MSCs) and mesoangioblasts (MABs) are multipotent cells that differentiate into specialized cells of mesodermal origin, including skeletal muscle cells. Because of their potential to differentiate into the skeletal muscle lineage, these multipotent cells have been tested for their capacity to participate in regeneration of damaged skeletal muscle in animal models of muscular dystrophy. MSCs and MABs infiltrate dystrophic muscle from the circulation, engraft into host fibers, and bring with them proteins that replace the functions of those missing or truncated. The potential for systemic delivery of these cells increases the feasibility of stem cell therapy for the large numbers of affected skeletal muscles in patients with muscular dystrophy. The present review focused on the results of preclinical studies with MSCs and MABs in animal models of muscular dystrophy. The goals of the present report were to (a) summarize recent results, (b) compare the efficacy of MSCs and MABs derived from different tissues in restoration of protein expression and/or improvement in muscle function, and (c) discuss future directions for translating these discoveries to the clinic. In addition, although systemic delivery of MABs and MSCs is of great importance for reaching dystrophic muscles, the potential concerns related to this method of stem cell transplantation are discussed.

182. A Novel Cell Therapy for Muscular Dystrophy by Bone Marrow Stromal Cell: Mesenchymal Stem Cell Derived from Bone Marrow Can Affect Skeletal Muscle Regeneration

182. A Novel Cell Therapy for Muscular Dystrophy by Bone Marrow Stromal Cell: Mesenchymal Stem Cell Derived from Bone Marrow Can Affect Skeletal Muscle Regeneration

Comparison of Deflazacort and Prednisone in Duchenne Muscular Dystrophy

How to Cite this Article: Karimzadeh P, Ghazavi A. Comparison of Deflazacort and Prednisone in Duchenne Muscular Dystrophy. IranianJournal of Child Neurology 2012;6(1):5-12. Objective Duchenne muscular dystrophy (DMD) is a degenerative disease that usually becomes clinically detectable in childhood as progressive proximal weakness. No cure is yet available for DMD, but the use of steroids improves muscle strength and function. This study has been carried out to select the best steroid for the management of DMD. Materials & Methods This study is a single-blind, randomized clinical trial with a sample volume of 34 DMD patients. Half of these patients were treated with deflazacort (0.9 mg/kg daily) and the other half with prednisone (0.75 mg/kg daily) for a period of 18 months. The motor function score and excess body weight were registered one year after the start and also at the end of the study and compared between the two groups. Results Deflazacort was more effective in the improvement of motor function after one year, but there was no significant difference between the two drugs at the end of the study (18 months after start). Weight gain after one year and at the end of the study was higher in prednisone group and steroid treatment with deflazacort appears to cause fewer side effects than prednisone regarding weight gain. Conclusion Deflazacort seems to be more effective than prednisone in the improvement of motor function causing fewer side effects, particularly weight gain. This medication may be important for the improvement of motor function and could be used as the best steroidal treatment for Duchenne muscular dystrophy. References Lankester BJA, Whitehouse MR, Gargan MF. Duchenne muscular dystrophy. Current Orthopedics 2007;21:298- 300. Wenger DR, Rang M. The art and practice of children’s orthopedics. Philadelphia, PA: Lippincott; Baltimore: Williams and Wilkins; 1993. Sussman M. Duchenne muscular dystrophy. J Am Acad Orthop Surg 2002 Mar-Apr;10(2):138-51. Escolar DM, Leshner RT. Muscular dystrophies. In: Swaiman KF, Ashwal S, Ferriero DM. Pediatric Neurology. 4th ed. Philadelphia: Mosby; 2006. p. 1967-86. Sarnat HB, Menkes JH. Disease of the motor unit. In: Menkes JH, Sarnat HB, editors. Child Neurology. 7th ed. Philadelphia: Lippincott Williams & Wilkins; 2005. p. 984-9. Biggar WD, Politano L, Harris VA, Passamano L, Vajsar J, Alman B, et al. Deflazacort in duchenne muscular dystrophy: a comparison of two different protocols. Neuromuscul disord 2004 Sep;14(8-9):476-82. Radley HG, De Luca A, Lynch GS, Grounds MD. Duchenne muscular dystrophy: focus on pharmaceutical and nutritional interventions. Int J Biochem Cell Biol 2007;39(3):469-77. Biggar WD, Klamut HJ, Demacio PC, Stevens DJ. Duchenne muscular dystrophy: current knowledge, treatment and future prospects. Clin Orthop Relat Res 2002 Aug;401:88-106. Sohn RL, Gussoni E. Stem cell therapy for muscular dystrophy. Expert Opin Biol Ther 2004 Jan;4(1):1-9. Houde S, Filiatrault M, Fournier A, Dube J, D’Arcy S, Berube D et al. Deflazacort use in duchenne muscular dystrophy: an 8-year follow-up. Pediatr Neurol 2008 Mar;38(3):200-6. Bonifati MD, Ruzza G, Bonometto P, Berardinelli A, Gorni K, Orcesi K et al. A multicenter double-bind randomized trial of deflazacort versus prednisone in Duchenne muscular dystrophy: analysis after 2 years. Basic Appl Myol 2000;10:171-5. Reitter B. Deflazacort vs. prednisone in Duchenne muscular dystrophy: trends of an ongoing study. Brain Dev 1995;17 Suppl:39-43. Polgar G, Promadhat V. Standard values. In: pulmonary function testing in children: techniques and standards. Philadelphia: W.B. Saunders, 1971:102-3. Biggar WD, Gingras M, Febling DL, Harris VA, Steele CA. Deflazacort treatment of Duchenne muscular dystrophy. J Pediatr 2001 Jan;138(1):45-50.

Necdin enhances muscle reconstitution of dystrophic muscle by vessel-associated progenitors, by promoting cell survival and myogenic differentiation

Improving stem cell therapy is a major goal for the treatment of muscle diseases, where physiological muscle regeneration is progressively exhausted. Vessel-associated stem cells, such as mesoangioblasts (MABs), appear to be the most promising cell type for the cell therapy for muscular dystrophies and have been shown to significantly contribute to restoration of muscle structure and function in different muscular dystrophy models. Here, we report that melanoma antigen-encoding gene (MAGE) protein necdin enhances muscle differentiation and regeneration by MABs. When necdin is constitutively overexpressed, it accelerates their differentiation and fusion in vitro and it increases their efficacy in reconstituting regenerating myofibres in the α-sarcoglycan dystrophic mouse. Moreover, necdin enhances survival when MABs are exposed to cytotoxic stimuli that mimic the inflammatory dystrophic environment. Taken together, these data demonstrate that overexpression of necdin may be a crucial tool to boost therapeutic applications of MABs in dystrophic muscle.

Editorial introductions

Current Opinion in Neurology was launched in 1988. It is one of a successful series of review journals whose unique format is designed to provide a systematic and critical assessment of the literature as presented in the many primary journals. The field of neurology is divided into 14 sections that are reviewed once a year. Each section is assigned a Section Editor, a leading authority in the area, who identifies the most important topics at that time. Here we are pleased to introduce the Journal's Section Editors for this issue. Section Editors Gerard SaidGerard SaidGérard Said is Consultant in Neurology at the Hospital of La Salpêtrière in Paris, France after retiring from Chairmanship of the Service of Neurology of the University Hospital of Bicêtre, France. In 1977–1978, he was a research fellow in the Department of Neurology of the University of Pennsylvania, Philadelphia, USA. He became Professor of Neurology in 1976, having previously been Assistant Professor at the University Hospital of Bicêtre and resident in neurology in Paris between 1968 and 1972. Professor Said was co-founder of the European Neurological Society (ENS) in 1986 and has been Secretary-General of the society since then, organising the yearly ENS congress since 1988. He is now Past-President of the ENS. Starting in 2006, he is Director of the Research Group on Neuromuscular Disorders of the World Federation of Neurology, and between 1998 and 2000 he was President of the Peripheral Nerve Society (PNS). Professor Said's main field of investigation is disorders of the peripheral nervous system, diabetic neuropathy, vasculitic neuropathy and infectious neuropathies. He graduated from the Medical School of the University in Paris in 1971. Sabrina SacconiSabrina SacconiSabrina Sacconi is Assistant Professor in Neurology, working in Neuromuscular Diseases Specialized Center of Nice University Hospital, France. She graduated from the University of Pavia Medical School, in Italy in 1997. She completed her residency in neurology at the University of Modena, Italy in 2002. During residency, in 2000–2002, she participated on the research fellow program in the Merritt Research Center, Department of Neurology of the Columbia University, New York, USA, and worked mainly on genetic of mitochondrial diseases. Starting from 2004, she had a permanent position as a Neurologist in Nice University Hospital. She developed clinical and basic research on neuromuscular diseases and contributed in creating the Neuromuscular Diseases Specialized Center for the diagnosis and management of rare neuromuscular disorders. At the same time, she obtained two Master degrees in Myology and in Peripheral Nervous System disorders at the University Pierre and Marie Curie and Paris 2 in Paris, France in 2006 and 2007, and a PhD in biology and cell physiology in 2008. At present, Sabrina Sacconi is the coordinator of a Research Group on Neuromuscular Disorders at the CNRS UMR 6543, at the University of Nice and coordinator of the clinical activity on neuromuscular diseases in Nice University Hospital. Her main fields of investigation are myopathy and neurogenetic disorders, and more specifically, she works of facioscapulohumeral muscular dystrophy physiopathology, genetic of mitochondrial diseases and cell therapy for muscular dystrophies.

O.9 Stem cell therapy of muscular dystrophies using exon skipping approach in GRMD dogs

O.9 Stem cell therapy of muscular dystrophies using exon skipping approach in GRMD dogs

14.1 T whole body MRI for detection of mesoangioblast stem cells in a murine model of duchenne muscular dystrophy

Noninvasive imaging procedures will be important for stem cell therapy for muscular dystrophy (MD). Mesoangioblasts regenerate muscle in animal models of muscular dystrophy. In this study, superparamagnetic iron oxide nanoparticles were used to visualize mesoangioblasts in vivo with MRI. Mesoangioblasts incorporated superparamagnetic iron oxide without transfection reagents, and cell differentiation was not negatively impacted. A custom-built radiofrequency coil with an adjustable field of view and 14.1 T magnet were used for whole-body MRI of mice. High-resolution images of mesoangioblasts in skeletal and cardiac muscle of Mdx mice were obtained following local delivery. Labeled cells were verified by Prussian blue staining and dystrophin expression, indicating that the wild-type mesoangioblasts survived and differentiated in muscle. Iron-labeled cells were detected with MRI in vivo 6 months following intracardiac injection but were determined to be activated macrophages. Iron-labeled cells were not detected by MRI following systemic delivery but were present in skeletal and cardiac muscle, visualized by Prussian blue staining. Systemically delivered mesoangioblasts were detected in lungs by Prussian blue staining and DiI but not by MRI in our study. MRI may be useful for short-term tracking of mesoangioblasts delivered locally but not for long-term monitoring or detection after systemic delivery.

Effective myotube formation in human adipose tissue-derived stem cells expressing dystrophin and myosin heavy chain by cellular fusion with mouse C2C12 myoblasts

Stem cell therapy for muscular dystrophies requires stem cells that are able to participate in the formation of new muscle fibers. However, the differentiation steps that are the most critical for this process are not clear. We investigated the myogenic phases of human adipose tissue-derived stem cells (hASCs) step by step and the capability of myotube formation according to the differentiation phase by cellular fusion with mouse myoblast C2C12 cells. In hASCs treated with 5-azacytidine and fibroblast growth factor-2 (FGF-2) for 1 day, the early differentiation step to express MyoD and myogenin was induced by FGF-2 treatment for 6 days. Dystrophin and myosin heavy chain (MyHC) expression was induced by hASC conditioned medium in the late differentiation step. Myotubes were observed only in hASCs undergoing the late differentiation step by cellular fusion with C2C12 cells. In contrast, hASCs that were normal or in the early stage were not involved in myotube formation. Our results indicate that stem cells expressing dystrophin and MyHC are more suitable for myotube formation by co-culture with myoblasts than normal or early differentiated stem cells expressing MyoD and myogenin.

Current advances in cell therapy strategies for muscular dystrophies

Introduction: Muscular dystrophies are a heterogeneous group of genetic diseases characterized by muscle weakness, wasting and degeneration. Cell therapy consists of delivering myogenic precursor cells to damaged tissue for the complementation of missing proteins and/or the regeneration of new muscle fibres.Areas covered: We focus on human candidate cells described so far (myoblasts, mesoangioblasts, pericytes, myoendothelial cells, CD133+ cells, aldehyde-dehydrogenase-positive cells, mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells), gene-based strategies developed to modify cells prior to injection, animal models (dystrophic and/or immunodeficient) used for pre-clinical studies, and clinical trials that have been performed using cell therapy strategies. The approaches are reviewed in terms of feasibility, hurdles, potential solutions and/or research areas from where the solution may come and potential application in terms of types of dystrophies and targets.Expert opinion: Cell therapy for muscular dystrophies should be put in the context of which dystrophy or muscle group is targeted, what tools are available at hand, but even more importantly what can cell therapy bring as compared with and/or in combination with other therapeutic strategies. The solution will probably be the right dosage of these combinations adapted to each dystrophy, or even to each type of mutation within a dystrophy.

MMP‐9 overexpression improves myogenic cell migration and engraftment

Myoblast migration requires matrix metalloproteinase (MMP) activity but the contribution of individual MMPs or tissue inhibitors of matrix metalloproteinase (TIMPs), particularly MMP-9 and TIMP-1, is lacking. Using two clones derived for differential regulation of MMP-2, MMP-9, and TIMP-1, we correlated protein expression with cell migration. MMP/TIMP regulation was determined by zymography, western blots, and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Cell migration was compared in vitro and after grafting into nude-mdx mouse muscles. C2M9 clones produced high MMP-9 and low MMP-2, and migrated better than C2F clones, which secreted low MMP-9, but overexpressed MMP-2 and TIMP-1. Improvement of C2F invasion by MMP-9 and inhibition of C2M9 migration by MMP-9 inhibitor I confirmed the role of MMP-9 and pointed to potential inhibition by TIMP-1. Higher complementation achieved by C2M9 grafts corroborated the beneficial effect of MMP-9 overexpression. Modulation of MMP-9 expression opens perspectives for improved efficacy of cell therapy for muscular dystrophies.