CD38 is constitutively expressed in the nucleus of human hematopoietic cells

CD38 is a type II glycoprotein that acts both as a bifunctional enzyme, responsible for the synthesis and hydrolysis of cyclic ADP-ribose, and as a signal-transducing surface receptor. Although CD38 was originally described as a plasma membrane molecule, several reports indicate that CD38 is expressed in the nucleus, even in cells known to be CD38 surface-negative. In this study, firstly we investigated the presence of nuclear CD38 by immunofluorescence and confocal microscopy using a panel of hematopoietic cell lines that exhibit different levels of CD38 plasma membrane expression. Our second aim was to explore the relationship between the nuclear and plasma membrane forms of CD38 in human cell lines which represent discrete early maturation stages of the human lymphoid and myeloid compartments. Our results indicate that CD38 is constitutively present in the nucleus of cells belonging to distinct lineages. Furthermore, nuclear CD38 appears to be independent of the plasma membrane pool. The presence of nuclear CD38 during different stages of hematopoietic differentiation suggests that it may play a role in the control of nuclear Ca(2+) homeostasis and NAD levels.     

Neurogenic potential of mesenchymal-like stem cells from human amniotic fluid: the influence of extracellular growth factors

Amniotic fluids contain human stem cells, among which mesenchymal stem cells could be isolated. These cells have multipotent differentiation ability and no tumorigenic potential after transplantation in mice. These features make them good candidates for in vitro studies and for therapeutic purposes. The aim of this study was to isolate mesenchymal stem cell-like cultures from different amniotic fluids in order to study in vitro their neurogenic potential and assess if this process could be reproducible and standardized. We focused attention on the possible differential effects of soluble growth factors. Immunophenotypical and molecular characterization showed that the 31 amniotic fluid-derived cultures expressed mesenchymal markers as well as some stemness properties. These cells also appeared to be responsive to purines or acetylcholine showing an intracellular calcium increase, also reported for mesenchymal stem cells derived from other sources. Interestingly, in the presence of retinoic acid, these cells assumed a neuronal-like morphology. In addition, functional and molecular analyses revealed that retinoic acid-treated cells showed immature electric functional properties, the expression of neuronal markers and stemness genes. In conclusion, even if further investigations are required, the results presented here contribute to support the finding that amniotic fluid contains cells able to differentiate in vitro towards neural-like lineage in the presence of retinoic acid. The ability of retinoic acid to induce a possible neuronal progenitor culture makes the model useful to study a possible in vivo transplantation of these cells and to contribute to define the protocols for cell therapy.     

mRNAs and miRNAs profiling of mesenchymal stem cells derived from amniotic fluid and skin: the double face of the coin

Mesenchymal stem cells (MSCs) can be isolated from different adult sources and, even if the minimal criteria for defining MSCs have been reported, the scientific question about the potential distinctions among MSCs derived from different sources is still open. In particular, it is debated whether MSCs of different origin have the same grade of stemness or whether the source affects their undifferentiated status. Here, we report not only the isolation and the traditional characterization of MSCs derived from amniotic fluid (AF-MSCs) and skin (S-MSCs) but also a molecular characterization based on mRNAs and miRNAs profiling. Our results show that, even if both AF- and S-MSCs are mostly regulated by the same pathways (such as Wnt, MAPK and TGF-β), there are some important differences at the molecular level that directly affect important cellular features, such as the ability to differentiate into adipocytes. In conclusion, even if further studies are necessary to improve the knowledge about the role of each dysregulated miRNAs gene, these differences may actually strengthen the question about the importance of tissue origin.     

Pro-inflammatory cytokines and microRNAs in male infertility

Molecular Biology Reports - Male infertility is a problem that affects 10–15% of men of reproductive age. In particular, gametogenesis is a complex process in which inflammation may play a...     

Adult mesenchymal stem cells for bone and cartilage engineering: effect of scaffold materials

Bone marrow is a useful cell source for skeletal tissue engineering approaches. In vitro differentiation of marrow mesenchymal stem cells (MSCs) to chondrocytes or osteoblasts can be induced by the addition of specific growth factors to the medium. The present study evaluated the behaviour of human MSCs cultured on various scaffolds to determine whether their differentiation can be induced by cell-matrix interactions. MSCs from bone marrow collected from the acetabulum during hip arthroplasty procedures were isolated by cell sorting, expanded and characterised by a flow cytometry system. Cells were grown on three different scaffolds (type I collagen, type I + II collagen and type I collagen + hydroxyapatite membranes) and analysed by histochemistry, immunohistochemistry and spectrophotometry (cell proliferation, alkaline phosphatase activity) at 15 and 30 days. Widely variable cell adhesion and proliferation was observed on the three scaffolds. MSCs grown on type I+II collagen differentiated to cells expressing chondrocyte markers, while those grown on type I collagen + hydroxyapatite differentiated into osteoblast-like cells. The study highlighted that human MSCs grown on different scaffold matrices may display different behaviours in terms of cell proliferation and phenotype expression without growth factor supplementation.     

Mesenchymal stem cells neuronal differentiation ability: a real perspective for nervous system repair?

Mesenchymal Stem Cells (MSCs) are a bone marrow-derived population present in adult tissues that possess the important property of dividing when called upon and of differentiating into specialized cells. The evidence that MSCs were able to transdifferentiate into specialized cells of tissues different from bone marrow, in particular into nervous cells, opened up the possibility of using MSCs to substitute damaged neurons, that are normally not replaced but lost, in order to repair the Nervous System. The first neuronal differentiation protocols were based on the use of a mixture of toxic drugs which induced MSCs to rapidly acquire a neuronal-like morphology with the expression of specific neuronal markers. However, many subsequent studies demonstrated that the morphological and molecular modifications of MSCs were probably due to a stress response, rather than to a real differentiation into neuronal cells, thus throwing into question the possible use of MSCs to repair the nervous system. Currently, some papers are suggesting again that it may be possible to induce neuronal differentiation of MSCs by using several differentiation protocols, and by accompanying the morphological evidence of differentiation with functional evidence, thus demonstrating that MSC-derived cells not only seem to be neurons, but that they also function like neurons. In this review, we have attempted to shed light on the capacity of MSCs to genuinely differentiate into nervous cells, and to identify the most reliable protocols for obtaining neurons from MSCs for nervous system repair.     

The effects of disodium pamidronate on human polymorphonuclear leukocytes and platelets: An <Emphasis Type="Italic">in vitro</Emphasis> study

Recent reports have indicated that, as well as having antiresorptive effects, bisphosphonates could have an application as anti-inflammatory drugs. Our aim was to investigate whether this anti-inflammatory action could be mediated by the nitric oxide (NO) released by the leukocytes migrating to the site of inflammation. In particular, we investigated in vitro the intracellular calcium concentration ([Ca²⁺]_i), the level of NO released by PMN and platelets, and the PMN myeloperoxidase activity after incubation with disodium pamidronate, since there was a postulated modulatory effect of this aminosubstituted bisphosphonate on leukocytes both in vitro and in vivo. Our data shows that the pamidronate treatment provoked a significant increase in the [Ca²⁺]_i parallel to the enhancement in NO release, suggesting a possible activation of constitutive nitric oxide synthase, while the myeloperoxidase activity was significantly reduced. In conclusion, we hypothesized that treatment with pamidronate could stimulate NO-production by cells present near the bone compartment, thus constituting a protective mechanism against bone resorption occurring during inflammation. In addition, PMN- and platelet-derived NO could act as a negative feed-back signal to restrict the inflammatory processes.