| 1. |
- Chapman, Katie, et al.
(författare)
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Inflammation without neuronal death triggers striatal neurogenesis comparable to stroke.
- 2015
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Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961. ; 83:Aug 20, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Ischemic stroke triggers neurogenesis from neural stem/progenitor cells (NSPCs) in the subventricular zone (SVZ) and migration of newly formed neuroblasts towards the damaged striatum where they differentiate to mature neurons. Whether it is the injury per se or the associated inflammation that gives rise to this endogenous neurogenic response is unknown. Here we showed that inflammation without corresponding neuronal loss caused by intrastriatal lipopolysaccharide (LPS) injection leads to striatal neurogenesis in rats comparable to that after a 30min middle cerebral artery occlusion, as characterized by striatal DCX+ neuroblast recruitment and mature NeuN+/BrdU+ neuron formation. Using global gene expression analysis, changes in several factors that could potentially regulate striatal neurogenesis were identified in microglia sorted from SVZ and striatum of LPS-injected and stroke-subjected rats. Among the upregulated factors, one chemokine, CXCL13, was found to promote neuroblast migration from neonatal mouse SVZ explants in vitro. However, neuroblast migration to the striatum was not affected in constitutive CXCL13 receptor CXCR5(-/-) mice subjected to stroke. Infarct volume and pro-inflammatory M1 microglia/macrophage density were increased in CXCR5(-/-) mice, suggesting that microglia-derived CXCL13, acting through CXCR5, might be involved in neuroprotection following stroke. Our findings raise the possibility that the inflammation accompanying an ischemic insult is the major inducer of striatal neurogenesis after stroke.
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| 2. |
- De La Rosa-Prieto, Carlos, et al.
(författare)
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Stroke alters behavior of human skin-derived neural progenitors after transplantation adjacent to neurogenic area in rat brain
- 2017
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Ingår i: Stem Cell Research and Therapy. - : Springer Science and Business Media LLC. - 1757-6512. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Intracerebral transplantation of human induced pluripotent stem cells (iPSCs) can ameliorate behavioral deficits in animal models of stroke. How the ischemic lesion affects the survival of the transplanted cells, their proliferation, migration, differentiation, and function is only partly understood. Methods: Here we have assessed the influence of the stroke-induced injury on grafts of human skin iPSCs-derived long-term neuroepithelial-like stem cells using transplantation into the rostral migratory stream (RMS), adjacent to the neurogenic subventricular zone, in adult rats as a model system. Results: We show that the occurrence of an ischemic lesion, induced by middle cerebral artery occlusion, in the striatum close to the transplant does not alter the survival, proliferation, or generation of neuroblasts or mature neurons or astrocytes from the grafted progenitors. In contrast, the migration and axonal projection patterns of the transplanted cells are markedly influenced. In the intact brain, the grafted cells send many fibers to the main olfactory bulb through the RMS and a few of them migrate in the same direction, reaching the first one third of this pathway. In the stroke-injured brain, on the other hand, the grafted cells only migrate toward the ischemic lesion and virtually no axonal outgrowth is observed in the RMS. Conclusions: Our findings indicate that signals released from the stroke-injured area regulate the migration of and fiber outgrowth from grafted human skin-derived neural progenitors and overcome the influence on these cellular properties exerted by the neurogenic area/RMS in the intact brain.
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| 3. |
- Ge, Ruimin
(författare)
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Inflammation and Stem Cell Therapy for Stroke
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ischemic stroke is a leading cause of death and disability worldwide. Currently, there is no treatment that can promote recovery in the chronic phase. It has been shown that neurogenesis occurs in ischemic striatum in rodents and probably also in humans. Moreover, blood-borne macrophages have been found to enhance spontaneous post- stroke recovery in mice. These findings have suggested potential new targets to improve functional restoration after stroke. In this thesis, we first showed that inflammation without neuronal loss is sufficient to trigger striatal neurogenesis comparable to that after stroke, indicating that inflammation might be the main inducer of post-stroke striatal neurogenesis. Using microarray on sorted microglia from subventricular zone (SVZ) and striatum, several factors were identified that potentially could regulate different steps of striatal neurogenesis after stroke. Some of the identified factors have previously been reported to regulate neural stem/progenitor cells (NSPC) proliferation or differentiation. We examined in some detail one factor, Cxcl13, and found that it promotes neuroblasts migration in vitro. Next, we provided evidence that monocyte-derived macrophages (MDM) can take the choroid plexus (CP)-cerebrospinal fluid (CSF) route for infiltration into the brain after cortical stroke. We found that in vitro-derived anti-inflammatory (M2-like) MDM delivered into CSF migrate into ischemic cortex, maintain their M2-like phenotype, and most importantly, improve recovery of motor and cognitive function in stroke-subjected mice without influencing infarct volume. These findings highlight the crucial role of inflammatory cells, such as microglia and macrophages, in post-stroke cellular plasticity and functional recovery. We also explored another approach for cell delivery into the brain using human induced pluripotent stem cells (iPSC)-derived long-term neuroepithelial-like stem (lt-NES) cells. Following our previous findings that transplantation of these cells and their derivatives promotes post-stroke motor function recovery, we showed that strokeinfluences the migration and axonal projection pattern of iPSC-derived lt-NES cells implanted adjacent to the neurogenic SVZ. These data indicate that the occurrence of ischemic injury strongly affects crucial parameters in the behavior of transplanted neural progenitors, which will be important to consider in a potential, future clinical translation. Finally, by combining immunoelectron microscopy, rabies virus-based trans-synaptic tracing, in vivo electrophysiological recordings and optogenetic techniques, we for the first time showed that neurons derived from transplanted iPSC-derived lt-NES cells receive functional synaptic inputs from host neurons located in the appropriate brain areas, e.g. ventral thalamus, after stroke. We demonstrated that tactile stimulation of nose and paws can activate or inhibit spontaneous activity in grafted neurons, providing evidence that they can become incorporated into injured cortical circuitry. Since we have found that transplanted M2-like MDM promote post-stroke recovery, possibly by modulating neuronal circuit plasticity, it seems highly warranted to examine whether delivery of M2-like MDM would further enhance the integration of neurons generated from grafted iPSC-derived lt-NES cells in the stroke model. Taken together, our findings raise the possibility that modulation of inflammatory mechanisms, delivery of M2-like MDM and transplantation of neurons generated from iPSC-derived lt-NES cells might become of value in future therapeutic approaches for improved functional recovery in stroke patients.
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| 4. |
- Laterza, Cecilia, et al.
(författare)
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Attenuation of reactive gliosis in stroke-injured mouse brain does not affect neurogenesis from grafted human iPSC-derived neural progenitors
- 2018
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- Induced pluripotent stem cells (iPSCs) or their progeny, derived from human somatic cells, can give rise to functional improvements after intracerebral transplantation in animal models of stroke. Previous studies have indicated that reactive gliosis, which is associated with stroke, inhibits neurogenesis from both endogenous and grafted neural stem/progenitor cells (NSPCs) of rodent origin. Here we have assessed whether reactive astrocytes affect the fate of human iPSC-derived NSPCs transplanted into stroke-injured brain. Mice with genetically attenuated reactive gliosis (deficient for GFAP and vimentin) were subjected to cortical stroke and cells were implanted adjacent to the ischemic lesion one week later. At 8 weeks after transplantation, immunohistochemical analysis showed that attenuated reactive gliosis did not affect neurogenesis or commitment towards glial lineage of the grafted NSPCs. Our findings, obtained in a human-to-mouse xenograft experiment, provide evidence that the reactive gliosis in stroke-injured brain does not affect the formation of new neurons from intracortically grafted human iPSC-derived NSPCs. However, for a potential clinical translation of these cells in stroke, it will be important to clarify whether the lack of effect of reactive gliosis on neurogenesis is observed also in a human-to-human experimental setting.
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| 5. |
- Laterza, Cecilia, et al.
(författare)
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Monocyte depletion early after stroke promotes neurogenesis from endogenous neural stem cells in adult brain
- 2017
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886. ; 297, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- Ischemic stroke, caused by middle cerebral artery occlusion, leads to long-lasting formation of new striatal neurons from neural stem/progenitor cells (NSPCs) in the subventricular zone (SVZ) of adult rodents. Concomitantly with this neurogenic response, SVZ exhibits activation of resident microglia and infiltrating monocytes. Here we show that depletion of circulating monocytes, using the anti-CCR2 antibody MC-21 during the first week after stroke, enhances striatal neurogenesis at one week post-insult, most likely by increasing short-term survival of the newly formed neuroblasts in the SVZ and adjacent striatum. Blocking monocyte recruitment did not alter the volume of the ischemic lesion but gave rise to reduced astrocyte activation in SVZ and adjacent striatum, which could contribute to the improved neuroblast survival. A similar decrease of astrocyte activation was found in and around human induced pluripotent stem cell (iPSC)-derived NSPCs transplanted into striatum at one week after stroke in monocyte-depleted mice. However, there was no effect on neurogenesis in the graft as determined 8 weeks after implantation. Our findings demonstrate, for the first time, that a specific cellular component of the early inflammatory reaction in SVZ and adjacent striatum following stroke, i.e., infiltrating monocytes, compromises the short-term neurogenic response neurogenesis from endogenous NSPCs.
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| 6. |
- Li, Peng, et al.
(författare)
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Transcriptional reactivation of OTX2, RX1 and SIX3 during reprogramming contributes to the generation of RPE cells from human iPSCs
- 2016
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Ingår i: International Journal of Biological Sciences. - : Ivyspring International Publisher. - 1449-2288. ; 12:5, s. 505-517
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Tidskriftsartikel (refereegranskat)abstract
- Directed differentiation of human induced pluripotent stem cells (iPSCs) into retinal pigmented epithelium (RPE) holds great promise in cell replacement therapy for patients suffering from degenerative eye diseases, including age-related macular degeneration (AMD). In this study, we generated iPSCs from human dermal fibroblasts (HDFs) by electroporation with episomal plasmid vectors encoding OCT4, SOX2, KLF4, L-MYC together with p53 suppression. Intriguingly, cell reprogramming resulted in a metastable transcriptional activation and selective demethylation of neural and retinal specification-associated genes, such as OTX2, RX1 and SIX3. In contrast, RPE progenitor genes were transcriptionally silent in HDFs and descendant iPSCs. Overexpression of OCT4 and SOX2 directly stimulated the expression of OTX2, RX1 and SIX3 in HDFs and iPSCs. Luciferase and chromatin immunoprecipitation (ChIP) assays further identified an OCT4- and two SOX2-binding sites located in the proximal promoter of OTX2. Histone acetylation and methylation on the local promoter also participated in the reactivation of OTX2. The transcriptional conversion of RX1 and SIX3 genes partially attributed to DNA demethylation. Subsequently, iPSCs were induced into the RPE cells displaying the characteristics of polygonal shapes and pigments, and expressing typical RPE cell markers. Taken together, our results establish readily efficient and safe protocols to produce iPSCs and iPSC-derived RPE cells, and underline that the reactivation of anterior neural transcription factor OTX2, eye field transcription factor RX1 and SIX3 in iPSCs is a feature of pluripotency acquisition and predetermines the potential of RPE differentiation.
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| 7. |
- Tornero, Daniel, et al.
(författare)
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Synaptic inputs from stroke-injured brain to grafted human stem cell-derived neurons activated by sensory stimuli
- 2017
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 140:3, s. 692-706
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Tidskriftsartikel (refereegranskat)abstract
- Transplanted neurons derived from stem cells have been proposed to improve function in animal models of human disease by various mechanisms such as neuronal replacement. However, whether the grafted neurons receive functional synaptic inputs from the recipient's brain and integrate into host neural circuitry is unknown. Here we studied the synaptic inputs from the host brain to grafted cortical neurons derived from human induced pluripotent stem cells after transplantation into stroke-injured rat cerebral cortex. Using the rabies virus-based trans-synaptic tracing method and immunoelectron microscopy, we demonstrate that the grafted neurons receive direct synaptic inputs from neurons in different host brain areas located in a pattern similar to that of neurons projecting to the corresponding endogenous cortical neurons in the intact brain. Electrophysiological in vivo recordings from the cortical implants show that physiological sensory stimuli, i.e. cutaneous stimulation of nose and paw, can activate or inhibit spontaneous activity in grafted neurons, indicating that at least some of the afferent inputs are functional. In agreement, we find using patch-clamp recordings that a portion of grafted neurons respond to photostimulation of virally transfected, channel-rhodopsin-2-expressing thalamo-cortical axons in acute brain slices. The present study demonstrates, for the first time, that the host brain regulates the activity of grafted neurons, providing strong evidence that transplanted human induced pluripotent stem cell-derived cortical neurons can become incorporated into injured cortical circuitry. Our findings support the idea that these neurons could contribute to functional recovery in stroke and other conditions causing neuronal loss in cerebral cortex.
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| 8. |
- Tornero Prieto, Daniel, et al.
(författare)
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Human induced pluripotent stem cell-derived cortical neurons integrate in stroke-injured cortex and improve functional recovery.
- 2013
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Ingår i: Brain. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 136:12, s. 3561-3577
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Tidskriftsartikel (refereegranskat)abstract
- Stem cell-based approaches to restore function after stroke through replacement of dead neurons require the generation of specific neuronal subtypes. Loss of neurons in the cerebral cortex is a major cause of stroke-induced neurological deficits in adult humans. Reprogramming of adult human somatic cells to induced pluripotent stem cells is a novel approach to produce patient-specific cells for autologous transplantation. Whether such cells can be converted to functional cortical neurons that survive and give rise to behavioural recovery after transplantation in the stroke-injured cerebral cortex is not known. We have generated progenitors in vitro, expressing specific cortical markers and giving rise to functional neurons, from long-term self-renewing neuroepithelial-like stem cells, produced from adult human fibroblast-derived induced pluripotent stem cells. At 2 months after transplantation into the stroke-damaged rat cortex, the cortically fated cells showed less proliferation and more efficient conversion to mature neurons with morphological and immunohistochemical characteristics of a cortical phenotype and higher axonal projection density as compared with non-fated cells. Pyramidal morphology and localization of the cells expressing the cortex-specific marker TBR1 in a certain layered pattern provided further evidence supporting the cortical phenotype of the fated, grafted cells, and electrophysiological recordings demonstrated their functionality. Both fated and non-fated cell-transplanted groups showed bilateral recovery of the impaired function in the stepping test compared with vehicle-injected animals. The behavioural improvement at this early time point was most likely not due to neuronal replacement and reconstruction of circuitry. At 5 months after stroke in immunocompromised rats, there was no tumour formation and the grafted cells exhibited electrophysiological properties of mature neurons with evidence of integration in host circuitry. Our findings show, for the first time, that human skin-derived induced pluripotent stem cells can be differentiated to cortical neuronal progenitors, which survive, differentiate to functional neurons and improve neurological outcome after intracortical implantation in a rat stroke model.
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| 9. |
- Wattananit, Somsak, et al.
(författare)
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Monocyte-derived macrophages contribute to spontaneous long-term functional recovery after stroke in mice
- 2016
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Ingår i: The Journal of Neuroscience. - 0270-6474. ; 36:15, s. 4182-4195
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Tidskriftsartikel (refereegranskat)abstract
- Stroke is a leading cause of disability and currently lacks effective therapy enabling long-term functional recovery. Ischemic brain injury causes local inflammation, which involves both activated resident microglia and infiltrating immune cells, including monocytes. Monocyte-derived macrophages (MDMs) exhibit a high degree of functional plasticity. Here, we determined the role of MDMs in longterm spontaneous functional recovery after middle cerebral artery occlusion in mice. Analyses by flow cytometry and immunocytochemistry revealed that monocytes home to the stroke-injured hemisphere., and that infiltration peaks 3 d after stroke. At day 7, half of the infiltratingMDMsexhibited a bias toward a proinflammatory phenotype and the other half toward an anti-inflammatory phenotype, but during the subsequent 2 weeks, MDMs with an anti-inflammatory phenotype dominated. Blocking monocyte recruitment using the anti-CCR2 antibody MC-21 during the first week after stroke abolished long-term behavioral recovery, as determined in corridor and staircase tests, and drastically decreased tissue expression of anti-inflammatory genes, including TGFβ, CD163, and Ym1. Our results show that spontaneously recruited monocytes to the injured brain early after the insult contribute to long-term functional recovery after stroke.
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