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PubMed2006

Functional neuronal differentiation of bone marrow-derived mesenchymal stem cells.

Recent results have shown the ability of bone marrow cells to migrate in the brain and to acquire neuronal or glial characteristics. In vitro, bone marrow-derived MSCs can be induced by chemical compounds to express markers of these lineages. In an effort to set up a mouse model of such differentiation, we addressed the neuronal potentiality of mouse MSCs (mMSCs) that we recently purified. These cells expressed nestin, a specific marker of neural progenitors. Under differentiating conditions, mMSCs display a distinct neuronal shape and express neuronal markers NF-L (neurofilament-light, or neurofilament 70 kDa) and class III beta-tubulin. Moreover, differentiated mMSCs acquire neuron-like functions characterized by a cytosolic calcium rise in response to various specific neuronal activators. Finally, we further demonstrated for the first time that clonal mMSCs and their progeny are competent to differentiate along the neuronal pathway, demonstrating that these bone marrow-derived stem cells share characteristics of widely multipotent stem cells unrestricted to mesenchymal differentiation pathways.

Animals↗

PubMed1986

Effect of adenine nucleotides on granulopoiesis and lithium-induced granulocytosis in long-term bone marrow cultures.

Studies were undertaken to evaluate the role of adenine nucleotides in regulating hematopoiesis using a long-term liquid culture system. In contrast to early investigations using clonogenic stem cell assays, where inhibitory effects were observed, adenosine and adenosine-5'-monophosphate (AMP) were found to stimulate myelopoiesis whereas the dibutyryl derivative of cyclic adenosine-3',5'-monophosphate (dcAMP) had either a modest inhibitory effect or no effect on long-term hematopoiesis. Dose effects for AMP enhancement of hematopoiesis were relatively narrow. When cultures were exposed to a broad range of concentrations (10 mM-10 nM), stimulation was only seen at a molar concentration of 1 X 10(-4) M. Stem cell assays revealed stimulation of multipotent stem cells (CFU-S), as well as committed progenitor cells (CFU-C). Lithium chloride has been shown to cause granulocytosis both in vivo and in vitro. Reductions in intracellular cAMP levels resulting from adenylate cyclase inhibition is a proposed mechanism for this stimulatory effect. However, lithium-induced granulocytosis in long-term cultures could not be blocked by the addition of dcAMP. Measurement of nucleotide levels on spent medium revealed rapid utilization and/or degradation of these reagents. This suggests that failure to abrogate the lithium effect with dcAMP may have been related to the inability to maintain constant intracellular concentrations. The varied observations regarding adenine nucleotide effects on hematopoiesis, as well as the reproducible stimulation by lithium, may be explained by our current appreciation of the complex adenylate cyclase system, which contains both inhibitory and stimulatory subunits for nucleotides and monovalent cations.

Adenosine↗

PubMed1997

Gastric epithelial morphogenesis in normal and transgenic mice.

The epithelium located in the corpus of the adult mouse stomach forms mucosal invaginations known as gastric units. Gastric units are populated by members of the pit, parietal, and neck-zymogenic cell lineages all of which are derived from multipotent stem cells. Gastric unit morphogenesis was examined in normal embryonic day 18 (E18) to postnatal day 28 (P28) FVB/N mice with electron microscopy and multilabel immunohistochemistry. E18 units appear as short, solid infoldings (primordial buds), 92% of whose cells represent pit, parietal, and neck cell precursors. Although the total number of cells per bud does not change from P1 to P7, immature cells decrease to 22% as differentiated pit, neck, and parietal cells appear. From P7 to P15, lineage precursors and their differentiated progeny increase and buds elongate. Between P15 and P21 the multipotent stem cell and its descendants are assembled into a distinct proliferative zone (isthmus) located in the midportion of each unit, and cellular migration-differentiation programs become compartmentalized. To examine the role of parietal cells in regulating gastric unit morphogenesis, nucleotides -1035 to +24 of the mouse H(+)-K(+)-adenosinetriphosphatase beta-subunit gene were used to express simian virus 40 large T antigen (SV40 TAg) exclusively in this lineage. SV40 TAg amplified the normally rare pre-parietal cell and disclosed a pre-parietal cell precursor. Pre-parietal cells and their precursors were the predominant cells in E18-P1 transgenic buds. At later stages of development (P1-P28) there was a block in differentiation of pre-parietal to mature parietal cells, a decrease in neck cells, and a marked depletion of zymogenic cells. These findings suggest that members of the parietal cell lineage are the source of instructions that affect the neck-zymogenic cell lineage, even before the gastric unit is compartmentalized into its anatomically distinct pit, isthmus, neck, and base regions.

Animals↗

PubMed2004

Membrane properties of rat embryonic multipotent neural stem cells.

We have characterized several potential stem cell markers and defined the membrane properties of rat fetal (E10.5) neural stem cells (NSC) by immunocytochemistry, electrophysiology and microarray analysis. Immunocytochemical analysis demonstrates specificity of expression of Sox1, ABCG2/Bcrp1, and shows that nucleostemin labels both progenitor and stem cell populations. NSCs, like hematopoietic stem cells, express high levels of aldehyde dehydrogenase (ALDH) as assessed by Aldefluor labeling. Microarray analysis of 96 transporters and channels showed that Glucose transporter 1 (Glut1/Slc2a1) expression is unique to fetal NSCs or other differentiated cells. Electrophysiological examination showed that fetal NSCs respond to acetylcholine and its agonists, such as nicotine and muscarine. NSCs express low levels of tetrodotoxin (TTX) sensitive and insensitive sodium channels and calcium channels while expressing at least three kinds of potassium channels. We find that gap junction communication is mediated by connexin (Cx)43 and Cx45, and is essential for NSC survival and proliferation. Overall, our results show that fetal NSCs exhibit a unique signature that can be used to determine their location and assess their ability to respond to their environment.

ATP Binding Cassette Transporter, Subfamily G, Mem↗

PubMed1996

Diphtheria toxin-mediated ablation of parietal cells in the stomach of transgenic mice.

The self-renewing epithelial populations present in the gastric units of the mouse stomach are descended from a multipotent stem cell and undergo an orderly migration-associated differentiation followed by apoptosis. The steady state census of the three principal cell types (acid-producing parietal cells, mucus-producing pit cells, and pepsinogen and intrinsic factor-producing zymogenic cells) is accurately controlled, despite marked differences in the rates of migration of each lineage. A transgenic mouse model has been created to define functional interrelationships between the proliferation, differentiation, and death programs of these lineages. Nucleotides -1035 to +24 of the noncatalytic beta subunit gene of mouse H+/K+-ATPase were used to direct expression of an attenuated diphtheria toxin A subunit in the parietal cell lineage. These transcriptional regulatory elements are not active in members of the pit and zymogenic lineages. Stomachs, prepared from postnatal day 28-80 transgenic mice and their normal littermates, were subjected to single- and multilabel immunohistochemical studies as well as qualitative and quantitative light and electron microscopic morphologic analyses. The toxin produced complete ablation of differentiated parietal cells. Loss of parietal cells was accompanied by a 5-fold increase in the number of undifferentiated granule-free cells located in the proliferative compartment of gastric units. This amplified population of granule-free cells included the multipotent stem cell as well as committed precursors of the pit and zymogenic lineages. Loss of mature parietal cells was also associated with (i) a block in the differentiation program of the zymogenic lineage with an accumulation of pre-neck cells and a depletion of their neck and mature zymogenic cell descendants, and (ii) an approximately 2-fold amplification of pit cells. These findings are consistent with the notion that epithelial homeostasis within gastric units is maintained by instructive interactions between their different cell lineages. Unlike pit and zymogenic cells, parietal cells complete their differentiation in the gastric unit's proliferative compartment before undergoing a bipolar migration along the unit. Thus, the mature parietal cell is in a strategic position to influence decision-making among gastric epithelial cell precursors and to modulate the migration-associated terminal differentiation programs of the pit and zymogenic lineages.

Aging↗

PubMed2005

Endothelial progenitor cells in health and disease.

There is currently great excitement and expectation in the stem cell community following the discovery that multipotent stem cells can be cultured from human fetal tissue and retain their ability to give rise to a variety of differentiated cell types found in all three embryonic germ layers. Although the earliest sites of hematopoietic cell and endothelial cell differentiation in the yolk sac blood islands were identified about 100 years ago, cells with hemangioblast properties have not yet been identified in vivo. Endothelial cells differentiate from angioblasts in the embryo and from endothelial progenitor cells, mesoangioblasts and multipotent adult progenitor cells in the adult bone marrow. Circulating endothelial progenitor cells (EPC) have been detected in the circulation after vascular injury and during tumor growth. The molecular and cellular mechanisms underlying EPC recruitment and differentiation are not yet understood, and remain as one of the central issues in stem cell biology. For many years, the prevailing dogma stated that the vessels in the embryo develop from endothelial progenitors, whereas sprouting of vessels in the adult results only from division of differentiated endothelial cells. Recent evidence, however, indicates that EPC contribute to vessel growth in the embryo and in ischemic, malignant or inflammed tissues in the adult, and can even be therapeutically used to stimulate vessel growth in ischemic tissues.

Animals↗

PubMed1989

Haemopoietic growth factors.

The growth and development of mature blood cells in vitro is supported by a series of glycoproteins with a range of biological activities. Many of these growth factors have been molecularly cloned, purified to homogeneity, and their biological effects determined on various target cells. Some of these growth factors promote the proliferation and differentiation of multipotent stem cells; others are more restricted in their action and, when used alone, can support only the development of lneage-restricted progenitor cells. When used in combinations however, the spectrum of target cells supported by these growth factors can be considerably enlarged. Furthermore, other molecules (which are not themselves growth promoters for multipotent stem cells) can synergise with these growth factors and permit primitive cells to undergo proliferation and development. These findings are likely to have major therapeutic implications.

Animals↗

PubMed2002

Generation of islets of Langerhans from adult pancreatic stem cells.

Ductal structures of the adult pancreas contain multipotent stem cells that, under controlled in vitro conditions, are able to self-renew and differentiate into functional islets of Langerhans. In vitro-generated islets, whether derived from stem cells of human, porcine, or mouse origin, exhibit temporal changes in mRNA transcripts for islet-associated markers as well as regulated insulin responses following glucose challenge. When in vitro-generated mouse islets were implanted into diabetic mice, neovascularization of the implant material occurred, followed by reversal of insulin-dependent diabetes. The possibility of growing functional islets from adult stem cells provides new opportunities to produce large numbers of islets, even autologous islets, for use as implants.

Animals↗

PubMedDate not supplied

The comparison of different protocols for expansion of umbilical-cord blood hematopoietic stem cells.

Hematopoiesis is maintained by the activity of multipotent stem cells, which have the dual capacity to self-renew and to differentiate into all of the blood cell lineages. The major challenge of stem cells based regenerative therapy is to expand ex vivo the primitive compartment to increase transplantable stem cells number. The present study was designed to evaluate several culture systems for in vitro maintenance of umbilical cord blood stem cells. The influences of different growth conditions such as stromal feeder layer, cytokines supplement and placental conditioned medium (PCM) have been evaluated over a relatively short period of time on CD34(+) cell expansion and maintenance of clonogenic progenitors. When cells were expanded on feeder layer in the presence of added cytokines and PCM on average a 2.96-fold increase of CD34(+)CD71(-) and a 3.13-fold increase of CD34(+)HLA-DR(-) was observed. The total number of colony forming cells (35 +/- 2.65) indicated also that the yield of clonogenic progenitors obtained with a combination of all factors was two folds higher than each of these factors alone and ten time above control (3.67 +/- 2.52). In conclusion, the results of our study clearly show that the ex vivo expansion of hematopoietic progenitor cells obtained from human umbilical cord blood is dependent on controlled experimental conditions, which might be helpful when designing culture systems for clinical applications.

Antigens, CD34↗

PubMed2004

Effects of dermal multipotent cell transplantation on skin wound healing.

There is increasing evidence that dermis contains adult multipotent stem cells. To investigate the effects of dermis-derived multipotent cells on wound healing, we transplanted a clonal population of dermis-derived multipotent cells (termed as DMCs) by topical and systemic application into the skin wound of rats with simple wounds and rats with combined wound and radiation injury. Our results suggest that both topical and systemic transplantation of DMCs accelerate the healing process in rats with a simple wound; the promoting effect by topical transplantation occurs earlier than systemic transplantation. However, systemic transplantation of DMCs promotes the healing process in irradiated rats, while topical transplantation of DMCs fails. Further studies on the mechanisms of DMCs to promote wound healing indicate that the supernatant of DMCs could promote the proliferation of fibroblasts and epidermal cells; DMCs expressed transcripts of a series of cytokines and extracellular matrix molecules, including VEGF, PDGF, HGF, TGF-beta, ICAM-1, VCAM-1, and Fibronectin, which were closely related to the wound healing by DNA microarray analysis. The implanted DMCs can engraft into recipient skin wounded tissues after transplantation by the FISH analysis with Y-chromosome-specific probe. Systemic transplantation of DMCs also promotes the recovery of peripheral white blood cells in irradiated rats. These results demonstrate the different effects of DMCs on wound healing in non-irradiated and irradiated rats and illustrate the importance of optimizing wound healing via the topical or systemic transplantation of stem cells.

Animals↗

PubMed2005

[Isolation and therapeutic use of human stem cells].

Nowadays, adult stem cells are the main target of biological research. Stem cell specific markers allow the extraction in enough quantity and high purity of multipotent cells from organic tissues, and their usage instead of the ethically reprehensible embryonal stem cells in experimental therapeutic purposes is also possible. The key point in the development of a new, stem-cell based therapeutic methodology is the determination of stem cell specific cell surface or cytoplasmatic antigens that makes reliable stem cell identification possible. Bone marrow derived multipotent stem cells can already be suitably identified, and other, more or less organic tissue-derived stem cell specific markers are also available. The first therapeutic interventions have been already done in diseases such as myocardial infarction or diabetes mellitus, and led to promising results.

Adult↗

PubMed1980

Commitment of stem cells to nerve cells and migration of nerve cells precursors in preparatory bud development in Hydra.

Budding in Hydra starts as an evagination of the double-layered tissue in the parent animal's gastric region. Five hours later the density of nerve cells in the bud's tissue doubles, representing the first detectable difference from the cellular composition of the surrounding tissue. These new nerve cells derive from multipotent stem cells which are in S-phase one day before evagination starts. Some of the bud's new nerve cells derive from stem cells which have migrated into the future bud's tissue after their commitment, apparently attracted by the bud anlage. The bud anlage recruits precursors of nerve cells even during starvation, during which nerve cell production ceases in other parts of the body. Furthermore, the bud anlage controls the duration of the development from commitment to final differentiation of the resulting nerve cells. Experiments with an inhibitor purified from hydra tissue indicate a tight correlation between stages of preparatory bud development and stages of recruitment of nerve cells for the bud. Whether or not precursors of nerve cells are involved in the control of bud formation in normal hydra, as compared to epithelial hydra which still bud though consisting of epithelial cells only, will be discussed.

Animals↗

PubMed1997

Examining the role of Paneth cells in the small intestine by lineage ablation in transgenic mice.

The Paneth cell lineage is one of four epithelial lineages derived from the adult mouse small intestine's multipotent stem cell. Mature Paneth cells secrete antimicrobial peptides (cryptdins), growth factors, as well as two gene products, a secreted phospholipase A2 and matrilysin, that has been implicated as modifiers of adenoma formation in mice containing a mutation in the tumor suppressor Apc. Immature Paneth cells are located just above and below the cell layer, in intestinal crypts, that has been proposed to contain the multipotent stem cell. Paneth cells differentiate during a downward migration to the crypt base. The location and direction of Paneth cell migration, their high density and long residency time at the crypt base, and the nature of their secreted gene products, suggest that they may influence the structure and/or function of the stem cell niche. Paneth cell ablation can therefore be viewed as an experimental manipulation of the cellular microenvironment that purportedly contains the stem cell and its immediate descendants. Two types of ablation experiments were performed in transgenic mice. Nucleotides -6500 to +34 of the mouse cryptdin-2 gene (CR2) were used to express an attenuated diphtheria toxin A fragment. Light and electron microscopic immunohistochemical analyses of several pedigrees of postnatal day 28 to 180 animals established that ablation of Paneth cells is accompanied by an increase in the proportion of undifferentiated crypt base columnar cells. These cells normally co-exist with Paneth cells. The ablation does not produce a detectable effect on the proliferation or terminal differentiation programs of the other three lineages or on host-microbial interactions. The last conclusion is based on the ability of crypts to remain free of microbes detectable by Gram and Warthin-Starry stains and by retention of the normal crypt-villus distribution of components of the diffuse gut-associated lymphoid tissue. CR2-directed expression of simian virus 40 large T antigen also results in a loss of mature Paneth cells but produces a marked amplification of crypt cells having a morphology intermediate between Paneth and granule goblet cells. EM immunohistochemical analyses suggest that intermediate cells can differentiate to mature goblet cells but not to Paneth cells, as they migrate up the crypt-villus axis. Our findings suggest that (i) stemness in the crypt is not defined by instructive interactions involving the Paneth cell; (ii) expressing a Paneth cell fate may require that precursors migrate to the crypt base; (iii) antimicrobial factors produced by Paneth cells are not required to prevent colonization of small intestinal crypts; and (iv) this lineage does not function to maintain the asymmetric crypt-villus distribution of components of the diffuse gut-associated lymphoid tissue.

Animals↗

PubMed1994

Enhancement of haemopoietic stem cell adherence to bone-marrow derived stroma by phyto-haemagglutinin treated leucocyte conditioned medium (PHA-LCM).

Stem cell adhesion to bone-marrow derived stroma, plays a crucial role in haemopoiesis. However, there is very little information as to the nature of the adhesion molecule. In this paper we have shown that human bone-marrow derived stroma can be established in tissue culture. This stroma is able to adhere human bone-marrow mononuclear cells including the multipotent stem cell, viz. CFU-GEMM. Their adherence increases when the stroma is treated with lymphokines in the form of PHA-treated leucocyte conditioned medium (PHA-LCM). Triton X-100 extracts of the untreated and PHA-LCM treated stroma were analysed on single dimension PAGE. It was observed that PHA-LCM treated stromal extracts showed two extra bands and an increase in the density of a band of approximately 14 kDa. Whether these changes have anything to do with the increased adhesion of stem cell is not yet known.

Bone Marrow↗

PubMed1999

A novel transgenic technique that allows specific marking of the neural crest cell lineage in mice.

Neural crest cells are embryonic, multipotent stem cells that give rise to various cell/tissue types and thus serve as a good model system for the study of cell specification and mechanisms of cell differentiation. For analysis of neural crest cell lineage, an efficient method has been devised for manipulating the mouse genome through the Cre-loxP system. We generated transgenic mice harboring a Cre gene driven by a promoter of protein 0 (P0). To detect the Cre-mediated DNA recombination, we crossed P0-Cre transgenic mice with CAG-CAT-Z indicator transgenic mice. The CAG-CAT-Z Tg line carries a lacZ gene downstream of a chicken beta-actin promoter and a "stuffer" fragment flanked by two loxP sequences, so that lacZ is expressed only when the stuffer is removed by the action of Cre recombinase. In three different P0-Cre lines crossed with CAG-CAT-Z Tg, embryos carrying both transgenes showed lacZ expression in tissues derived from neural crest cells, such as spinal dorsal root ganglia, sympathetic nervous system, enteric nervous system, and ventral craniofacial mesenchyme at stages later than 9.0 dpc. These findings give some insights into neural crest cell differentiation in mammals. We believe that P0-Cre transgenic mice will facilitate many interesting experiments, including lineage analysis, purification, and genetic manipulation of the mammalian neural crest cells.

Animals↗

PubMed2006

Rosiglitazone modifies the adipogenic potential of human muscle satellite cells.

AIMS/HYPOTHESIS: Satellite cells are responsible for postnatal skeletal muscle regeneration. It has been demonstrated that mouse satellite cells behave as multipotent stem cells. We studied the differentiation capacities of human satellite cells and evaluated the effect of the insulin sensitiser rosiglitazone, a well known peroxisome proliferative activated receptor gamma (PPARG) agonist, on their adipogenic conversion. SUBJECTS, MATERIALS AND METHODS: We obtained human satellite cells from human muscle biopsies of healthy subjects by single-fibre isolation and cultured them under myogenic, osteogenic and adipogenic conditions. Moreover, we compared the morphological features and the adipose-specific gene expression profiling, as assessed by quantitative PCR, between adipocytes differentiated from human satellite cells and those obtained from the stromal vascular fraction of human visceral fat. RESULTS: We proved by morphological analysis, mRNA expression and immunohistochemistry that human satellite cells are able to differentiate into myotubes, adipocytes and osteocytes. The addition of rosiglitazone to the adipogenic medium strongly activated PPARG expression and enhanced adipogenesis in human satellite cells, but did not in itself trigger the complete adipogenic programme. Moreover, we observed a decrease in wingless-type MMTV integration site family member 10B and an upregulation of growth differentiation factor 8 expression, both being independent of PPARG activation. CONCLUSIONS/INTERPRETATION: Human satellite cells possess a clear adipogenic potential that could explain the presence of mature adipocytes within skeletal muscle in pathological conditions such as obesity, type 2 diabetes and ageing-related sarcopenia. Rosiglitazone treatment, while enhancing adipogenesis, induces a more favourable pattern of adipocytokine expression in satellite-derived fat cells. This could partially counteract the worsening effect of intermuscular adipose tissue depots on muscle insulin sensitivity.

Adipogenesis↗

PubMed1984

Interstitial cell migration in Hydra attenuata. II. Selective migration of nerve cell precursors as the basis for position-dependent nerve cell differentiation.

In Hydra, the interstitial cells constitute a multipotent stem cell system, forming nerve cells and nematocytes. Differentiation of these product cells varies in an axially dependent manner along the body column, and either of two simple hypotheses can explain this phenomena: (1) position-dependent stem cell determination or (2) selective migration of committed precursor cells. This latter hypothesis predicts that the migrating interstitial cell population is enriched with cells which are restricted in their proliferation and differentiation potential. To test this idea several developmental properties of the migrating cells were compared with those of the total interstitial cell population. The results indicate that those interstitial cells that migrate are not a random sample of the whole population. They contain a lower proportion of stem cells, as shown both by a slower growth rate and by a reduced capacity for clone formation. The migrating population is specifically enriched with interstitial cells that are committed to nerve differentiation. Coupled with previous measurements on migration rates, these findings suggest that the observed position-dependent pattern of nerve differentiation results from the selective redistribution of committed nerve cell precursors.

Animals↗

PubMed2006

Technology Insight: adult stem cells in cartilage regeneration and tissue engineering.

Articular cartilage, the load-bearing tissue of the joint, has limited repair and regeneration potential. The scarcity of treatment modalities for large chondral defects has motivated attempts to engineer cartilage tissue constructs that can meet the functional demands of this tissue in vivo. Cartilage tissue engineering requires three components: cells, scaffold, and environment. Adult stem cells, specifically multipotent mesenchymal stem cells, are considered the cell type of choice for tissue engineering, because of the ease with which they can be isolated and expanded and their multilineage differentiation capabilities. Successful outcome of cell-based cartilage tissue engineering ultimately depends on the proper differentiation of stem cells into chondrocytes and the assembly of the appropriate cartilaginous matrix to achieve the load-bearing capabilities of the natural articular cartilage. Multiple requirements, including growth factors, signaling molecules, and physical influences, need to be met. Adult mesenchymal stem-cell-based tissue engineering is a promising technology for the development of a transplantable cartilage replacement to improve joint function.

Cartilage, Articular↗