| 1. |
- Adler, Andrew, et al.
(författare)
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Transsynaptic tracing and its emerging use to assess graftreconstructed neural circuits
- 2020
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 38:6, s. 716-726
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Tidskriftsartikel (refereegranskat)abstract
- Fetal neural progenitor grafts have been evaluated in preclinical animal models of spinal cord injury and Parkinson’s disease for decades, but the initial reliance on primary tissue as a cell source limited the scale of their clinical translatability. With the development of robust methods to differentiate human pluripotent stem cells to specific neural subtypes, cell replacement therapy holds renewed promise to treat a variety of neurodegenerative diseases and injuries at scale. As these cell sources are evaluated in preclinical models, new transsynaptic tracing methods are making it possible to study the connectivity between host and graft neurons with greater speed and detail than was previously possible. To date, these studies have revealed that widespread, long-lasting, and anatomically-appropriate synaptic contacts are established between host and graft neurons, as well as new aspects of host-graft connectivity which may be relevant to clinical cell replacement therapy. It is not yet clear, however, whether the synaptic connectivity between graft and host neurons is as celltype specific as it is in the endogenous nervous system, or whether that connectivity is responsible for the functional efficacy of cell replacement therapy. Here, we review evidence suggesting that the new contacts established between host and graft neuronsmay indeed be cell-type specific, and how transsynaptic tracing can be used inthe future to further elucidate the mechanisms of graft-mediated functional recovery in spinal cord injury and Parkinson’s disease.
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| 2. |
- Ameri, Jacqueline, et al.
(författare)
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FGF2 Specifies hESC-Derived Definitive Endoderm into Foregut/Midgut Cell Lineages in a Concentration-Dependent Manner.
- 2010
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 28, s. 45-56
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Tidskriftsartikel (refereegranskat)abstract
- Fibroblast growth factor (FGF) signaling controls axis formation during endoderm development. Studies in lower vertebrates have demonstrated that FGF2 primarily patterns the ventral foregut endoderm into liver and lung, whereas FGF4 exhibits broad anterior-posterior and left-right patterning activities. Furthermore, an inductive role of FGF2 during dorsal pancreas formation has been shown. However, whether FGF2 plays a similar role during human endoderm development remains unknown. Here, we show that FGF2 specifies hESC-derived definitive endoderm (DE) into different foregut lineages in a dosage-dependent manner. Specifically, increasing concentrations of FGF2 inhibits hepatocyte differentiation, whereas intermediate concentration of FGF2 promotes differentiation towards a pancreatic cell fate. At high FGF2 levels specification of midgut endoderm into small intestinal progenitors is increased at the expense of PDX1+ pancreatic progenitors. High FGF2 concentrations also promote differentiation towards an anterior foregut pulmonary cell fate. Finally, by dissecting the FGF receptor intracellular pathway that regulates pancreas specification, we demonstrate for the first time to our knowledge that induction of PDX1+ pancreatic progenitors relies on FGF2-mediated activation of the MAPK signaling pathway. Altogether, these observations suggest a broader gut endodermal patterning activity of FGF2 that corresponds to what has previously been advocated for FGF4, implying a functional switch from FGF4 to FGF2 during evolution. Thus, our results provide new knowledge of how cell fate specification of human DE is controlled - facts that will be of great value for future regenerative cell therapies.
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| 3. |
- Avaliani, Natalia, et al.
(författare)
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Optogenetics reveal delayed afferent synaptogenesis on grafted human induced pluripotent stem cell-derived neural progenitors.
- 2014
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 32:12, s. 3088-3098
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Tidskriftsartikel (refereegranskat)abstract
- Reprogramming of somatic cells into pluripotency stem cell state have opened new opportunities in cell replacement therapy and disease modeling in a number of neurological disorders. It still remains unknown, however, to what degree the grafted human induced pluripotent stem cells (hiPSCs) differentiate into a functional neuronal phenotype and if they integrate into the host circuitry. Here we present a detailed characterization of the functional properties and synaptic integration of hiPSC-derived neurons grafted in an in vitro model of hyperexcitable epileptic tissue, namely organotypic hippocampal slice cultures (OHSC), and in adult rats in vivo. The hiPSCs were first differentiated into long-term self-renewing neuroepithelial stem (lt-NES) cells, which are known to form primarily GABAergic neurons. When differentiated in OHSCs for six weeks, lt-NES cell-derived neurons displayed neuronal properties such as TTX-sensitive sodium currents and action potentials (APs), as well as both spontaneous and evoked postsynaptic currents, indicating functional afferent synaptic inputs. The grafted cells had a distinct electrophysiological profile compared to host cells in the OHSCs with higher input resistance, lower resting membrane potential and APs with lower amplitude and longer duration. To investigate the origin of synaptic afferents to the grafted lt-NES cell-derived neurons, the host neurons were transduced with Channelrhodopsin-2 (ChR2) and optogenetically activated by blue light. Simultaneous recordings of synaptic currents in grafted lt-NES cell-derived neurons using whole-cell patch-clamp technique at 6 weeks after grafting revealed limited synaptic connections from host neurons. Longer differentiation times, up to 24 weeks after grafting in vivo, revealed more mature intrinsic properties and extensive synaptic afferents from host neurons to the It-NES cell-derived neurons, suggesting that these cells require extended time for differentiation/maturation and synaptogenesis. However, even at this later time-point, the grafted cells maintained a higher input resistance. These data indicate that grafted lt-NES cell-derived neurons receive ample afferent input from the host brain. Since the lt-NES cells used in this study show a strong propensity for GABAergic differentiation, the host-to-graft synaptic afferents may facilitate inhibitory neurotransmitter release, and normalize hyperexcitable neuronal networks in brain diseases, e.g. such as epilepsy. Stem Cells 2014.
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| 4. |
- Behnan, Jinan, et al.
(författare)
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Recruited brain tumor-derived mesenchymal stem cells contribute to brain tumor progression.
- 2014
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 32:5, s. 1110-1123
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Tidskriftsartikel (refereegranskat)abstract
- The identity of the cells that contribute to brain tumor structure and progression remains unclear. Mesenchymal stem cells (MSCs) have recently been isolated from normal mouse brain. Here, we report the infiltration of MSC-like cells into the GL261 murine glioma model. These Brain Tumor derived Mesenchymal Stem Cells (BT-MSCs) are defined with the phenotype (Lin-Sca-1+CD9+CD44+CD166+/-) and have multipotent differentiation capacity. We show that the infiltration of BT-MSCs correlates to tumor progression; furthermore, BT-MSCs increased the proliferation rate of GL261 cells in vitro. For the first time, we report that the majority of GL261 cells expressed mesenchymal phenotype under both adherent and sphere culture conditions in vitro, and that the non-MSC population is non-tumorigenic in vivo. Although the GL261 cell line expressed mesenchymal phenotype markers in vitro, most BT-MSCs are recruited cells from host origin in both wild type GL261 inoculated into GFP-transgenic mice and GL261-GFP cells inoculated into wild type mice. We show the expression of chemokine receptors CXCR4 and CXCR6 on different recruited cell populations. In vivo, the GL261 cells change marker profile, and acquire a phenotype that is more similar to cells growing in sphere culture conditions. Finally, we identify a BT-MSC population in human glioblastoma that is CD44+CD9+CD166+ both in freshly isolated and culture-expanded cells. Our data indicate that cells with MSC-like phenotype infiltrate into the tumor stroma and play an important role in tumor cell growth in vitro and in vivo. Thus we suggest that targeting BT-MSCs could be a possible strategy for treating glioblastoma patients. Stem Cells 2013.
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| 5. |
- Berglin-Enquist, Ida, et al.
(författare)
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Successful Low-Risk Hematopoietic Cell Therapy in a Mouse Model of Type 1 Gaucher Disease
- 2009
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 27:3, s. 744-752
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Tidskriftsartikel (refereegranskat)abstract
- Hematopoietic stem cell-based gene therapy offers the possibility of permanent correction for genetic disorders of the hematopoietic system. However, optimization of present protocols is required before gene therapy can be safely applied as general treatment of genetic diseases. In this study we have used a mouse model of type 1 Gaucher disease (GD) to demonstrate the feasibility of a low-risk conditioning regimen instead of standard radiation, which is associated with severe adverse effects. We first wanted to establish what level of engraftment and glucosylceramidase (GCase) activity is required to correct the pathology of the type 1 GD mouse. Our results demonstrate that a median wild-type (WT) cell engraftment of 7%, corresponding to GCase activity levels above 10 nmoles/hour and mg protein, was sufficient to reverse pathology in bone marrow and spleen in the GD mouse. Moreover, we applied nonmyeloablative doses of busulfan as a pretransplant conditioning regimen and show that even WT cell engraftment in the range of 1%-10% can confer a beneficial therapeutical outcome in this disease model. Taken together, our data provide encouraging evidence for the possibility of developing safe and efficient conditioning protocols for diseases that require only a low level of normal or gene-corrected cells for a permanent and beneficial therapeutic outcome. STEM CELLS 2009; 27: 744-752
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| 6. |
- Blank Savukinas, Ulrika, et al.
(författare)
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The Bystander Effect : Mesenchymal Stem Cell-Mediated Lung Repair
- 2016
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 34:6, s. 1437-1444
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Forskningsöversikt (refereegranskat)abstract
- Mesenchymal stem or stromal cells (MSCs), a heterogeneous subset of adult stem/progenitor cells, have surfaced as potential therapeutic units with significant clinical benefit for a wide spectrum of disease conditions, including those affecting the lung. Although MSCs carry both self-renewal and multilineage differentiation abilities, current dogma holds that MSCs mainly contribute to tissue regeneration and repair by modulating the host tissue via secreted cues. Thus, the therapeutic benefit of MSCs is thought to derive from so called bystander effects. The regenerative mechanisms employed by MSCs in the lung include modulation of the immune system as well as promotion of epithelial and endothelial repair. Apart from secreted factors, a number of recent findings suggest that MSCs engage in mitochondrial transfer and shedding of membrane vesicles as a means to enhance tissue repair following injury. Furthermore, it is becoming increasingly clear that MSCs are an integral component of epithelial lung stem cell niches. As such, MSCs play an important role in coupling information from the environment to stem and progenitor populations, such that homeostasis can be ensured even in the face of injury. It is the aim of this review to outline the major mechanisms by which MSCs contribute to lung regeneration, synthesizing recent preclinical findings with data from clinical trials and potential for future therapy
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| 7. |
- Blixt Wojciechowski, Anita, et al.
(författare)
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Long-term survival and glial differentiation of the brain-derived precursor cell line RN33B after subretinal transplantation to adult normal rats
- 2002
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 20:2, s. 163-173
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Tidskriftsartikel (refereegranskat)abstract
- The potential use of in vitro-expanded precursor cells or cell lines in repair includes transplantation of such cells for cell replacement purposes and the activation of host cells to provide "self-repair." Recently, we have reported that cells from the brain-derived cell line RN33B (derived from the embryonic rat medullary raphe and immortalized through retroviral transduction of the temperature-sensitive mutant of the simian virus 40 ([SV40] large T-antigen) survive for at least 4 weeks, integrate, and differentiate after subretinal grafting to normal adult rats. Here, we demonstrate that grafts of these cells survive for at least 4 months after subretinal transplantation to adult, normal immunosuppressed rats. Implanted cells integrate into the retinal pigment epithelium and the inner retinal layers, and the anterior part of the optic nerve. In addition, the RN33B cells migrate within the retina, occupying the whole retina from one eccentricity to the other. A large fraction of the grafted cells differentiate into glial cells, as shown by double labeling of the reporter genes LacZ or green fluorescent protein, and several glial markers, including oligodendrocytes. However, the cells did not differentiate into retinal neurons, judging from their lack of expression of retinal neuronal phenotypic markers. A significant number of the implanted cells in the host retina were in a proliferative stage, judging from proliferative cell nuclear antigen and SV40 large T-antigen immunohistochemistry. To conclude, the cells survived, integrated, and migrated over long distances within the host. Therefore, our results may be advantageous for future design of therapeutic strategies, since such cells may have the potential of being a source of, for example, growth factor delivery in experimental models of retinal degeneration.
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| 8. |
- Blixt Wojciechowski, Anita, et al.
(författare)
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Survival and long distance migration of brain-derived precursor cells transplanted to adult rat retina
- 2004
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Ingår i: Stem Cells. - : AlphaMed Press. - 1549-4918 .- 1066-5099. ; 22:1, s. 27-38
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Tidskriftsartikel (refereegranskat)abstract
- Neural precursor cells transplanted to adult retina can integrate into the host. This is especially true when the neural precursor rat cell line RN33B is used. This cell line carries the reporter genes LacZ and green fluorescent protein (GFP). In grafted rat eyes, RN33B cells are localized from one eccentricity to the other of the host retina. In the present study, whole-mounted retinas were analyzed to obtain a more appropriate evaluation of the amount of transgene-expressing cells and the migratory capacity of these cells 3 and 8 weeks post-transplantation. Quantification was made of the number of beta-galactosidase- and GFP-expressing cells with a semiautomatized stereological cell counting system. With the same system, delineation of the distribution area of the grafted cells was also performed. At 3 weeks, 68% of the grafted eyes contained marker-expressing cells, whereas at 8 weeks only 35% of the eyes contained such cells. Counting of marker-expressing cells demonstrated a lower number of transgene-expressing cells at 3 weeks compared with 8 weeks post-transplantation. The distribution pattern of marker gene-expressing cells revealed cells occupying up to 21% at 3 weeks and up to 68% at 8 weeks of the entire host retina post-grafting. The precursor cells survived well in the adult retina although the most striking feature of the RN33B cell line was its extraordinary migratory capacity. This capability could be useful if precursor cells are used to deliver necessary genes or gene products that need to be distributed over a large diseased area.
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| 9. |
- Brederlau, Anke, 1968, et al.
(författare)
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Transplantation of human embryonic stem cell-derived cells to a rat model of Parkinson's disease: effect of in vitro differentiation on graft survival and teratoma formation.
- 2006
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1066-5099 .- 1549-4918. ; 24:6, s. 1433-40
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Tidskriftsartikel (refereegranskat)abstract
- Human embryonic stem cells (hESCs) have been proposed as a source of dopamine (DA) neurons for transplantation in Parkinson's disease (PD). We have investigated the effect of in vitro predifferentiation on in vivo survival and differentiation of hESCs implanted into the 6-OHDA (6-hydroxydopamine)-lesion rat model of PD. The hESCs were cocultured with PA6 cells for 16, 20, or 23 days, leading to the in vitro differentiation into DA neurons. Grafted hESC-derived cells survived well and expressed neuronal markers. However, very few exhibited a DA neuron phenotype. Reversal of lesion-induced motor deficits was not observed. Rats grafted with hESCs predifferentiated in vitro for 16 days developed severe teratomas, whereas most rats grafted with hESCs predifferentiated for 20 and 23 days remained healthy until the end of the experiment. This indicates that prolonged in vitro differentiation of hESCs is essential for preventing formation of teratomas.
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| 10. |
- Carreira, Bruno Pereira, et al.
(författare)
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Nitric Oxide Stimulates the Proliferation of Neural Stem Cells Bypassing the Epidermal Growth Factor Receptor
- 2010
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 28:7, s. 1219-1230
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Tidskriftsartikel (refereegranskat)abstract
- Nitric oxide (NO) was described to inhibit the proliferation of neural stem cells. Some evidence suggests that NO, under certain conditions, can also promote cell proliferation, although the mechanisms responsible for a potential proliferative effect of NO in neural stem cells have remained unaddressed. In this work, we investigated and characterized the proliferative effect of NO in cell cultures obtained from the mouse subventricular zone. We found that the NO donor NOC-18 (10 mu M) increased cell proliferation, whereas higher concentrations (100 mu M) inhibited cell proliferation. Increased cell proliferation was detected rapidly following exposure to NO and was prevented by blocking the mitogen-activated kinase (MAPK) pathway, independently of the epidermal growth factor (EGF) receptor. Downstream of the EGF receptor, NO activated p21Ras and the MAPK pathway, resulting in a decrease in the nuclear presence of the cyclin-dependent kinase inhibitor I, p27(KIP1), allowing for cell cycle progression. Furthermore, in a mouse model that shows increased proliferation of neural stem cells in the hippocampus following seizure injury, we observed that the absence of inducible nitric oxide synthase (iNOS(-/-) mice) prevented the increase in cell proliferation observed following seizures in wild-type mice, showing that NO from iNOS origin is important for increased cell proliferation following a brain insult. Overall, we show that NO is able to stimulate the proliferation of neural stem cells bypassing the EGF receptor and promoting cell division. Moreover, under pathophysiological conditions in vivo, NO from iNOS origin also promotes proliferation in the hippocampus. STEM CELLS 2010:28:1219-1230
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