CD133+ cells isolated from various sources and their role in future clinical perspective

Background. CD133 is a member of a novel family of cell surface glycoproteins. Initially, the expression of CD133 antigen was seen only in the hematopoietic derived CD34+ stem cells. At present, CD133 expression is demonstrated in undifferentiated epithelium, different types of tumors and myogenic cells. CD133+ neurosphere cells isolated from brain are able to differentiate into both neurons and glial cells. These data suggested that CD133 could be a specific marker for various stem and progenitor cell populations. Objectives. The main goal would be to describe the role for CD133 as a marker of stem cells able to engraft and differentiate, to form functional non-hematopoietic adult lineages and contribute to disease amelioration via tissue regeneration. Results/conclusion. In conclusion, since the rise of CD133 antigen as a suitable stem cell marker, the possible use of CD133+ stem cells in therapeutic applications has opened a new promising field in the treatment of degenerating diseases. The human circulating cells expressing the CD133 antigen behave as a stem cell population capable of commitment to hematopoietic, endothelial and myogenic lineages. CD133 cell therapy may represent a promising treatment for many diseases

Cell replacement therapy in neuromuscular and neurodegenerative diseases

In the past 10 years there have been important advances in our understanding of the pathogenesis and pathophysiology of inherited and acquired neuromuscular and neurodegenerative diseases. Cell-based therapies were used to promote muscle regeneration with the hope that the host cells repopulated the muscle and improved muscle function and pathology. Stem cells were preferable for therapeutic applications, due to their capacity for self-renewal and differentiative potential. Adult stem cells were found in various tissues of the body and they were able to maintain, generate, and replace terminally differentiated cells within their own specific tissue because of cell turnover or tissue injury. It became clear that these cells could participate in regeneration of more than just their resident organ. In the last years, encouraging results were obtained by utilizing stem cells with degenerative diseases such as Parkinson\u2019s disease, Motor Neuron Disease, Multiple Sclerosis, Amyotrophic Lateral Sclerosis and Alzheimer\u2019s Disease. Moreover, different works demonstrated how myogenic and non-myogenic stem cells could exert a significant role in the treatment of muscular dystrophies. The knowledge of stem cells coupled with novel stem cell-based delivery systems, and advances in modulation of immune mechanisms, modification of the activity of mutant genes, and performing gene replacement therapies will expand our ability to treat neuromuscular and neurodegenerative diseases

Clinical applications of mesenchymal stem cells in chronic diseases

Extraordinary progress in understanding several key features of stem cells has been made in the last ten years, including definition of the niche, and identification of signals regulating mobilization and homing as well as partial understanding of the mechanisms controlling self-renewal, commitment, and differentiation. This progress produced invaluable tools for the development of rational cell therapy protocols that have yielded positive results in preclinical models of genetic and acquired diseases and, in several cases, have entered clinical experimentation with positive outcome. Adult mesenchymal stem cells (MSCs) are nonhematopoietic cells with multilineage potential to differentiate into various tissues of mesodermal origin. They can be isolated from bone marrow and other tissues and have the capacity to extensively proliferate in vitro. Moreover, MSCs have also been shown to produce anti-inflammatory molecules which can modulate humoral and cellular immune responses. Considering their regenerative potential and immunoregulatory effect, MSC therapy is a promising tool in the treatment of degenerative, inflammatory, and autoimmune diseases. It is obvious that much work remains to be done to increase our knowledge of the mechanisms regulating development, homeostasis, and tissue repair and thus to provide new tools to implement the efficacy of cell therapy trials

In Vivo Tracking of Stem cell by Nanotechnologies : Future Prospect for Mouse to Human Translation

Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. Dynamic determination of stem cell migration and distribution in real time is essential for optimizing treatments in preclinical models and designing clinical protocols. Recent developments in the use of nanotechnologies have contributed to advance of the high-resolution in vivo imaging methods, including the positron emission tomography, the single-photon emission computed tomography, the magnetic resonance imaging, and microcomputed tomography. This review examines the use of nanotechnologies for stem cell tracking, the many contrast agents, and detectors that have been proposed and suggest future directions for mouse to human translation of these techniques, for both therapeutic and diagnostic purposes

Impact of Muscular Dystrophy on the Regenerative Properties of interstitial Muscle Cells

In the muscle tissue exist different cell populations that are able to participate in muscle regeneration. The presence of distinct muscle progenitor subtypes with different cellular plasticity raises the question of whether and how these cells participate to the muscle ontogeny. The regenerative capacity of skeletal muscle is due to a combination of factors which leads to the activation of the satellite cell (SC) pool. Recently, several studies documented the role of interstitial muscle cells during muscle regeneration. In this study we analyzed the Lin 12(CD31 12CD45 12TER119 12) human interstitial muscle cells isolated from healthy and DMD muscle biopsies. Among human interstitial muscle cells we found cell population expressing CD56 (NCAM), CXCR4, CD29 (\u3b2-1 Integrin) satellite markers and cells positive for CD34 and PDGFalpha (FAP) with adipogenic and fibrogenic potentials and cells expressing CD44, CD29, CD73 antigens with mesenchymal (MSC) potential. The number of satellite and mesenchymal interstitial cells was reduced in older DMD muscle with a loss of their clonogenicity and myogenic potential. Contrarily, we observed an age-dependent increase in DMD adipogenic interstitial cells together with an overexpression of PDGFR\u3b1 confirmed by WB analysis. In vivo studies of intra-muscular transplantation of the selected sorted human interstitial subpopulations in scid/mdx mice (dystrophic animal model which allow the transplantation of human cells) confirmed the failure of the muscle regenerative capacities of satellite and MSC cells isolated from DMD muscle biopsies with an increased in vivo adipogenesis. In light of all these results, we confirmed the exhaustion of myogenic progenitors in dystrophic DMD muscle tissues providing insights of DMD pathology

Proliferation and Clonal Analysis of Muscle Derived CD133+ Stem Cell Subpopulations Define a Depletion of Mesenchymal Population in DMD Patients

In the muscle exist different stem cell populations that are able to participate in muscle regeneration. In patients with Duchenne Muscular Dystrophies (DMD) there is a depletion of stem cell populations due to continuous regeneration cycles. Moreover, recent findings supported the notion that heterogeneity is a hallmark of stem cells. It is known that these cell populations express a variety of surface markers including CD29, CD56, CD44, CD90, CD105, STRO\u20131. Here we have focused our attention on the so-called MDSCs (Muscle-Derived Stem Cells) that can be rather considered as satellite precursors. In the past our group focused its attention on a stem cell population expressing CD133 antigens on its surface. The analysis of muscle-derived CD133+ cells showed that they have been characterized for their regenerative potential in vivo, as well as their ability to repopulate the satellite cell niche in healthy muscles. The cells obtained from muscle biopsies of DMD and orthopaedic patients, were sorted for specific subpopulations and then cloned. Original subpopulations and their clones were characterized for proliferation and differentiation behaviour, as well as for the expression of surface markers by flow cytometry. However, we found in the CD133+ MDSCs a phenotypic heterogeneity in the presence of some surface antigens: in the same cell population we found an oscillation of expression of endothelial, myogenic and mesenchymal markers. Based on these assumptions we sorted some cell subpopulations obtained from muscles of healthy patients and DMD children: mesenchymal-like cells (CD133+ CD73+ CD44+ CD29+ CD34- CD45-); endothelial-like cells (CD133+ CD90+ CD146+ CD31+ CD45-) and myogenic-like cells (CD133+ CD56+ CD45- CD34+/-). These subpopulations were cloned and analyzed for their capacity to proliferate and differentiate into the endothelial and myogenic lineages. In these experiments we found stem cell properties, particularly in the mesenchymal-like CD133+ clones. In fact these cells show clonogenic potential and well differentiate into endothelial and myogenic cells. Instead we found that this subpopulation is compromised in DMD patients both in terms of percentage of expression, proliferative and differentiative capacities. In conclusion, our study showed that muscle-derived CD133+ cells represent a heterogeneous population of mesenchymal, myogenic and endothelial progenitors and that the first population appears to be the most compromised in DMD patients. Further experiments are needed in order to understand whether CD133+ mesenchymal population could be a good candidate for clinical applications in muscular dystrophies

CD20-related signaling pathway is differently activated in normal and dystrophic circulating CD133+ stem cells

Among the heterogeneous population of circulating hematopoietic and endothelial progenitors, we identified a subpopulation of CD133+ cells displaying myogenic properties. Unexpectedly, we observed the expression of the B-cell marker CD20 in blood-derived CD133+ stem cells. The CD20 antigen plays a role in the modulation of intracellular calcium homeostasis through signaling pathways activation. Several observations suggest that an increase in intracellular calcium concentration ([Ca2+]i) could be involved in the etiology of the Duchenne muscular dystrophy (DMD). Here, we show that a CD20-related signaling pathway able to induce an increase in [Ca2+]i is differently activated after brain derived neurotrophic factor (BDNF) stimulation of normal and dystrophic blood-derived CD133+ stem cells, supporting the assumption of a \u201cCD20-related calcium impairment-affecting dystrophic cells. Presented findings represent the starting point toward the expansion of knowledge on pathways involved in the pathology of DMD and in the behavior of dystrophic blood-derived CD133+ stem cells

Expression of CD20 reveals a new store-operated calcium entry modulator in skeletal muscle

Among the scarce available data about the biological role of the membrane protein CD20, there is some evidence that this protein functions as a store-operated Ca(2+) channel and/or regulates transmembrane Ca(2+) trafficking. Recent findings indicate that store-operated Ca(2+) entry (SOCE) plays a central role in skeletal muscle function and development, but there remain a number of unresolved issues relating to SOCE modulation in this tissue. Here we describe CD20 expression in skeletal muscle, verifying its membrane localization in myoblasts and adult muscle fibers. Additionally, we show that inhibition of CD20 through antibody binding or gene silencing resulted in specific impairment of SOCE in C2C12 myoblasts. Our results provide novel insights into the CD20 expression pattern, and suggest that functional CD20 is required for SOCE to consistently occur in C2C12 myoblasts. These findings may contribute to future identification of mechanisms and molecules involved in the fine regulation of store-operated Ca(2+) entry in skeletal muscle