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Armstrong L.,Northumbria University | Lako M.,Northumbria University | Buckley N.,King's College London | Lappin T.R.J.,Queen's University of Belfast | And 4 more authors.
Stem Cells | Year: 2012

To celebrate 30 years of peer-reviewed publication of cutting edge stem cell research in Stem Cells, the first journal devoted to this promising field, we pause to review how far we have come in the three-decade lifetime of the Journal. To do this, we will present our views of the 10 most significant developments that have advanced stem cell biology where it is today. With the increasing rate of new data, it is natural that the bulk of these developments would have occurred in recent years, but we must not think that stem cell biology is a young science. The idea of a stem cell has actually been around for quite a long time having appeared in the scientific literature as early as 1868 with Haeckels' concept of a stamzelle as an uncommitted or undifferentiated cell responsible for producing many types of new cells to repair the body [Naturliche Schopfungsgeschichte, 1868; Berlin: Georg Reimer] but it took many years to obtain hard evidence in support of this theory. Not until the work of James Till and Ernest McCulloch in the 1960s did we have proof of the existence of stem cells and until the derivation of embryonal carcinoma cells in the 1960s-1970s and the first embryonic stem cell in 1981, such adult or tissue-specific stem cells were the only known class. The first issue of Stem Cells was published in 1981; no small wonder that most of its papers were devoted to hematopoietic progenitors. More recently, induced pluripotent stem cells (iPSCs) have been developed, and this is proving to be a fertile area of investigation as shown by the volume of publications appearing not only in Stem Cells but also in other journals over the last 5 years. The reader will note that many of the articles in this special issue are concerned with iPSC; however, this reflects the current surge of interest in the topic rather than any deliberate attempt to ignore other areas of stem cell investigation. © AlphaMed Press.

Gomez-Villafuertes R.,Complutense University of Madrid | Rodriguez-Jimenez F.J.,Research Center Principe Felipe | Alastrue-Agudo A.,Research Center Principe Felipe | Stojkovic M.,Spebo Medical | And 3 more authors.
Cell Transplantation | Year: 2015

Spinal cord injury (SCI) is a major cause of paralysis with no current therapies. Following SCI, large amounts of ATP and other nucleotides are released by the traumatized tissue leading to the activation of purinergic receptors that, in coordination with growth factors, induce lesion remodeling and repair. We found that adult mammalian ependymal spinal cord-derived stem/progenitor cells (epSPCs) are capable of responding to ATP and other nucleotidic compounds, mainly through the activation of the ionotropic P2X4, P2X7, and the metabotropic P2Y1 and P2Y4 purinergic receptors. A comparative study between epSPCs from healthy rats versus epSPCis, obtained after SCI, shows a downregulation of P2Y1 receptor together with an upregulation of P2Y4 receptor in epSPCis. Moreover, spinal cord after severe traumatic contusion shows early and persistent increases in the expression of P2X4 and P2X7 receptors around the injury, which are completely reversed when epSPCis were ectopically transplanted. Since epSPCi transplantation significantly rescues neurological function after SCI in parallel to inhibition of the induced P2 ionotropic receptors, a potential avenue is open for therapeutic alternatives in SCI treatments based on purinergic receptors and the endogenous reparative modulation. © 2015 Cognizant Comm. Corp.

Lukovic D.,Retina Group | Moreno-Manzano V.,Research Center Principe Felipe | Klabusay M.,St Annes University Hospital Brno | Stojkovic M.,Spebo Medical | And 3 more authors.
Frontiers in Genetics | Year: 2014

Several studies have demonstrated the important role of non-coding RNAs as regulators of posttranscriptional processes, including stem cells self-renewal and neural differentiation. Human embryonic stem cells (hESCs) and induced pluripotent stem cells (ihPSCs) show enormous potential in regenerative medicine due to their capacity to differentiate to virtually any type of cells of human body. Deciphering the role of non-coding RNAs in pluripotency, self-renewal and neural differentiation will reveal new molecular mechanisms involved in induction and maintenances of pluripotent state as well as triggering these cells toward clinically relevant cells for transplantation. In this brief review we will summarize recently published studies which reveal the role of non-coding RNAs in pluripotency and neural differentiation of hESCs and ihPSC. © 014 Lukovic, Moreno-Manzano, Klabusay, Stojkovic, Bhattacharya and Erceg.

Lukovic D.,Cabimer Centro Andaluz Of Biologia Molecular Y Medicina Regenerativa | Valdes-Sanchez L.,Cabimer Centro Andaluz Of Biologia Molecular Y Medicina Regenerativa | Sanchez-Vera I.,Cabimer Centro Andaluz Of Biologia Molecular Y Medicina Regenerativa | Moreno-Manzano V.,Research Center Principe Felipe | And 3 more authors.
Stem Cells | Year: 2014

Spinal cord injury results in neural loss and consequently motor and sensory impairment below the injury. Reactive astrocytes contribute to formation of glial scar, thus impeding axonal regeneration, through secretion of extracellular matrix molecules, chondroitin sulfate proteoglycans (CSPGs). In this study, we analyze lesion site tissue to reveal the possible mechanism underlying the functional recovery after cell transplantation of human embryonic stem cell (hESC)-derived oligodendrocyte progenitor cell (OPC) and motoneuron progenitors (MP) and propose that transplanted cells increase astrogliosis through the regenerative signaling pathways activated in the host tissue that may crucial for restoring locomotor ability. We show that the transplantation of hESC-derived OPC and MP promotes astrogliosis, through activation of Jagged1-dependent Notch and Jak/STAT signaling that support axonal survival. The transplanted cells in synergism with reactive astrocytes create permissive environment in which the expression of detrimental genes (Cspg, Tenascins, and genes involved in SLIT/ROBO signaling) was significantly decreased while expression of beneficial ones (Laminins and Fibronectin) was increased. According to our data, this mechanism is activated in all transplantation groups independently of the level of locomotor recovery. These results indicate that modifying the beneficial function of reactive astrocytes could be a feasible therapeutic strategy for spinal cord injury in future. © AlphaMed Press 2013.

Rodriguez-Jimenez F.J.,Research Center Principe Felipe | Alastrue-Agudo A.,Research Center Principe Felipe | Erceg S.,Cabimer Centro Andaluz Of Biologia Molecular Y Medicina Regenerativa | Stojkovic M.,Spebo Medical | Moreno-Manzano V.,Research Center Principe Felipe
Stem Cells | Year: 2012

Spinal cord injury is a major cause of paralysis with no currently effective therapies. Induction of self-renewal and proliferation of endogenous regenerative machinery with noninvasive and nontoxic therapies could constitute a real hope and an alternative to cell transplantation for spinal cord injury patients. We previously showed that FM19G11 promotes differentiation of adult spinal cord-derived ependymal stem cells under hypoxia. Interestingly, FM19G11 induces self-renewal of these ependymal stem cells grown under normoxia. The analysis of the mechanism of action revealed an early increment of mitochondrial uncoupling protein 1 and 2 with an early drop of ATP, followed by a subsequent compensatory recovery with activated mitochondrial metabolism and the induction of glucose uptake by upregulation of the glucose transporter GLUT-4. Here we show that phosphorylation of AKT and AMP-activated kinase (AMPK) is involved in FM19G11-dependent activation of GLUT-4, glucose influx, and consequently in stem cell self-renewal. Small interfering RNA of uncoupling protein 1/2, GLUT-4 and pharmacological inhibitors of AKT, mTOR and AMPK signaling blocked the FM19G11-dependent induction of the self-renewal-related markers Sox2, Oct4, and Notch1. Importantly, FM19G11-treated animals showed accelerated locomotor recovery. In vivo intrathecal sustained administration of FM19G11 in rats after spinal cord injury showed more neurofilament TUJ1-positive fibers crossing the injured area surrounded by an increase of neural precursor Vimentin-positive cells. Overall, FM19G11 exerts an important influence on the self-renewal of ependymal stem progenitor cells with a plausible neuroprotective role, providing functional benefits for spinal cord injury treatment. © AlphaMed Press.

Lukovic D.,Cabimer Centro Andaluz Of Biologya Molecular Y Medicina Regenerativa | Stojkovic M.,Spebo Medical | Stojkovic M.,University of Kragujevac | Moreno-Manzano V.,Research Center Principe Felipe | And 2 more authors.
Stem Cells and Development | Year: 2014

Halting the first clinical trial on the use of embryonic stem cell derivatives for spinal cord injury resulted in disappointment and created concerns about the future use of pluripotent stem cell-based therapy in the treatment of human diseases. This article presents reflections and concerns related to the halted embryonic stem cell-based clinical trial and discusses some important and controversial issues for achieving safe and successful cell therapy. This manuscript highlights two important points for successful translation of pluripotent stem cell-based therapy in clinics: (i) reproducible xeno-free growth and differentiation of pluripotent stem cells in good manufacturing practice conditions as the prerequisites to ensure a defined and controlled cell source and (ii) extensive studies in small and large animal models and comprehensive basic studies to determine any adverse or toxic effects of transplanted cells, especially teratoma formation, in addition to improving surgical procedure and cell delivery system. © 2014 Mary Ann Liebert, Inc.

Lukovic D.,Research Center principe Felipe | Moreno-Manzano V.,Research Center Principe Felipe | Lopez-Mocholi E.,Research Center Principe Felipe | Rodriguez-Jimenez F.J.,Research Center principe Felipe | And 7 more authors.
Scientific Reports | Year: 2015

Spinal cord injury (SCI) results in neural loss and consequently motor and sensory impairment below the injury. There are currently no effective therapies for the treatment of traumatic SCI in humans. Various animal models have been developed to mimic human SCI. Widely used animal models of SCI are complete or partial transection or experimental contusion and compression, with both bearing controversy as to which one more appropriately reproduces the human SCI functional consequences. Here we present in details the widely used procedure of complete spinal cord transection as a faithful animal model to investigate neural and functional repair of the damaged tissue by exogenous human transplanted cells. This injury model offers the advantage of complete damage to a spinal cord at a defined place and time, is relatively simple to standardize and is highly reproducible. © 2015, Nature Publishing Group. All rights reserved.

Rodriguez-Jimenez F.J.,Research Center Principe Felipe | Alastrue A.,Research Center Principe Felipe | Stojkovic M.,Spebo Medical | Stojkovic M.,University of Kragujevac | And 2 more authors.
Cell and Tissue Research | Year: 2016

Ion channels included in the family of Connexins (Cx) have been reported to influence the secondary expansion of traumatic spinal cord injury (SCI) and neuropathic pain following SCI. However, Cxs also contribute to spinal cord neurogenesis during the remyelinating process and functional recovery after SCI. Certain Cxs have been recently related to the control of cell proliferation and the differentiation of neuronal progenitors. Adult spinal-cord-derived ependymal stem progenitor cells (epSPC) show high expression levels of Cx50 in non-pathological conditions and lower expression when they actively proliferate after injury (epSPCi). We explore the role of Cx50 in the ependymal population in the modulation of Sox2, a crucial factor of neural progenitor self-renewal and a promising target for promoting neuronal-cell-fate induction for neuronal tissue repair. Short-interfering-RNA ablation or over-expression of Cx50 regulates the expression of Sox2 in both epSPC and epSPCi. Interestingly, Cx50 and Sox2 co-localize at the nucleus indicating a potential role for this ion channel beyond cell-to-cell communication in the spinal cord. In vivo and in vitro experiments with Clotrimazole, a specific pharmacological modulator of Cx50, show the convergent higher expression of Cx50 and Sox2 in the isolated epSPC/epSPCi and in spinal cord tissue. Therefore, the pharmacological modulation of Cx50 might constitute an interesting mechanism for Sox2 induction to modulate the endogenous regenerative potential of neuronal tissue with a potential application in regenerative therapies. © 2016 Springer-Verlag Berlin Heidelberg

PubMed | Research Center Principe Felipe and Spebo Medical
Type: Journal Article | Journal: International journal of molecular sciences | Year: 2015

Ion channels included in the family of Connexins (Cx) help to control cell proliferation and differentiation of neuronal progenitors. Here we explored the role of Connexin 50 (Cx50) in cell fate modulation of adult spinal cord derived neural precursors located in the ependymal canal (epSPC). epSPC from non-injured animals showed high expression levels of Cx50 compared to epSPC from animals with spinal cord injury (SCI) (epSPCi). When epSPC or epSPCi were induced to spontaneously differentiate in vitro we found that Cx50 favors glial cell fate, since higher expression levels, endogenous or by over-expression of Cx50, augmented the expression of the astrocyte marker GFAP and impaired the neuronal marker Tuj1. Cx50 was found in both the cytoplasm and nucleus of glial cells, astrocytes and oligodendrocyte-derived cells. Similar expression patterns were found in primary cultures of mature astrocytes. In addition, opposite expression profile for nuclear Cx50 was observed when epSPC and activated epSPCi were conducted to differentiate into mature oligodendrocytes, suggesting a different role for this ion channel in spinal cord beyond cell-to-cell communication. In vivo detection of Cx50 by immunohistochemistry showed a defined location in gray matter in non-injured tissues and at the epicenter of the injury after SCI. epSPCi transplantation, which accelerates locomotion regeneration by a neuroprotective effect after acute SCI is associated with a lower signal of Cx50 within the injured area, suggesting a minor or detrimental contribution of this ion channel in spinal cord regeneration by activated epSPCi.

Erceg S.,Cabimer Centro Andaluz Of Biologia Molecular Y Medicina Regenerativa | Lukovic D.,Cabimer Centro Andaluz Of Biologia Molecular Y Medicina Regenerativa | Moreno-Manzano V.,Neural Regeneration Laboratory | Stojkovic M.,Spebo Medical | And 2 more authors.
Current Protocols in Stem Cell Biology | Year: 2012

Here we provide a protocol for differentiation of human embryonic stem cells (hESC) into cerebellar neurons using a novel defined culture method. This protocol is based on the application of inductive signaling factors involved in the early patterning of the cerebellar region of the neural tube, followed by the application of factors responsible for cerebellar neuron specification. Human pluripotent stem cells are induced to form spherical embryonic-like structures called embryoid bodies (EBs) and neuroepithelial tube-like rosettes using defined chemical conditions. In the presence of FGF, Wnt, and RA signaling factors the rosettes were specified to OTX2-expressing cells. Further specification of derived cells involves application of BMP factors involved in early development of granule cell progenitors, followed by mitogens and neurotrophins. It typically takes 5 weeks to generate the functional cerebellar granule neurons. This protocol is feeder-free, applies human recombinant factors, and produces high yield of desired neurons. © 2012 by John Wiley & Sons, Inc.

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