Epidermal neural crest stem cell-derived glia enhance neurotrophic elements in an ex vivo model of spinal cord injury

The combined application of stem cells and three-dimensional bioprinting scaffolds for the repair of spinal cord injury

Spinal cord injury is considered one of the most difficult injuries to repair and has one of the worst prognoses for injuries to the nervous system. Following surgery, the poor regenerative capacity of nerve cells and the generation of new scars can make it very difficult for the impaired nervous system to restore its neural functionality. Traditional treatments can only alleviate secondary injuries but cannot fundamentally repair the spinal cord. Consequently, there is a critical need to develop new treatments to promote functional repair after spinal cord injury. Over recent years, there have been several developments in the use of stem cell therapy for the treatment of spinal cord injury. Alongside significant developments in the field of tissue engineering, three-dimensional bioprinting technology has become a hot research topic due to its ability to accurately print complex structures. This led to the loading of three-dimensional bioprinting scaffolds which provided precise cell localization. These three-dimensional bioprinting scaffolds could repair damaged neural circuits and had the potential to repair the damaged spinal cord. In this review, we discuss the mechanisms underlying simple stem cell therapy, the application of different types of stem cells for the treatment of spinal cord injury, and the different manufacturing methods for three-dimensional bioprinting scaffolds. In particular, we focus on the development of three-dimensional bioprinting scaffolds for the treatment of spinal cord injury.

Oxytocin Receptor Expression in Hair Follicle Stem Cells: A Promising Model for Biological and Therapeutic Discovery in Neuropsychiatric Disorders

The intricate nature of the human brain and the limitations of existing model systems to study molecular and cellular causes of neuropsychiatric disorders represent a major challenge for basic research. The promising progress in patient-derived stem cell technology and in our knowledge on the role of the brain oxytocin (OXT) system in health and disease offer new possibilities in that direction. In this study, the rat hair follicle stem cells (HFSCs) were isolated and expanded in vitro. The expression of oxytocin receptors (OXTR) was evaluated in these cells. The cellular viability was assessed 12 h post stimulation with OXT. The activation of OXTR-coupled intracellular signaling cascades, following OXT treatment was determined. Also, the influence of OXT on neurite outgrowth and cytoskeletal rearrangement were defined. The assessment of OXTR protein expression revealed this receptor is expressed abundantly in HFSCs. As evidenced by the cell viability assay, no adverse or cytotoxic effects were detected following 12 h treatment with different concentrations of OXT. Moreover, OXTR stimulation by OXT resulted in ERK1/2, CREB, and eEF2 activation, neurite length alterations, and cytoskeletal rearrangements that reveal the functionality of this receptor in HFSCs. Here, we introduced the rat HFSCs as an easy-to-obtain stem cell model that express functional OXTR. This cell-based model can contribute to our understanding of the progression and treatment of neuropsychiatric disorders with oxytocinergic system deficiency.

The beneficial effects of chick embryo extract preconditioning on hair follicle stem cells: A promising strategy to generate Schwann cells

The beneficial effects of hair follicle stem cells in different animal models of nervous system conditions have been extensively studied. While chick embryo extract (CEE) has been used as a growth medium supplement for these stem cells, this is the first study to show the effect of CEE on them. The rat hair follicle stem cells were isolated and supplemented with 10% fetal bovine serum plus 10% CEE. The migration rate, proliferative capacity and multipotency were evaluated along with morphometric alteration and differentiation direction. The proteome analysis of CEE content identified effective factors of CEE that probably regulate fate and function of stem cells. The CEE enhances the migration rate of stem cells from explanted bulges as well as their proliferation, likely due to activation of AP-1 and translationally controlled tumour protein (TCTP) by thioredoxin found in CEE. The increased length of outgrowth may be the result of cyclic AMP response element binding protein (CREB) phosphorylation triggered by active CamKII contained in CEE. Further, CEE supplementation upregulates the expression of vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor. The elevated expression of target genes and proteins may be due to CREB, AP-1 and c-Myc activation in these stem cells. Given the increased transcript levels of neurotrophins, VEGF, and the expression of PDGFR-α, S100B, MBP and SOX-10 protein, it is possible that CEE promotes the fate of these stem cells towards Schwann cells.

Differentiation of rat bone marrow mesenchymal stem cells into neurons induced by bone morphogenetic protein 7 in vitro

OBJECTIVES

Spinal cord injury (SCI) is caused by external direct or indirect factors with high disability rate, which may even endanger the life of patients. To explore the role of bone morphogenetic protein 7 (BMP-7) in the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) into neurons in vitro.

METHODS

BMSCs were isolated and cultured by whole bone marrow adherence method. Adipogenic induction and osteogenic differentiation were used to test the multi⁃directional differentiation ability of BMSCs.

RESULTS

After 28 days of adipogenic induction, BMSCs showed lipid droplets in the cytoplasm. After osteogenic induction, there were opaque lumps of mineral nodules in BMSCs. There were also orange-red or red mineral nodules in the extracellular matrix. The BMSCs in the 75 ng/ml BMP-7 group were morphologically similar to the neurons. After induction with BMP-7 for 2 h, the NF200 mRNA expression was higher, mRNA expression levels of SYN1, MAP2 and GFAP were higher. Positive rate of immunofluorescence staining in the BMP-7 group was notably increased. The positive rate of NSE immunofluorescence staining in the BMP-7 group was higher.

CONCLUSION

BMP-7 can induce rat BMSCs to differentiate into neurons in vitro.

Therapeutic potential of hair follicle-derived stem cell intranasal transplantation in a rat model of ischemic stroke

BACKGROUND

Stem cell-based therapy has received considerable attention as a potential candidate in the treatment of ischemic stroke; however, employing an appropriate type of stem cells and an effective delivery route are still challenging. In the present study, we investigated the therapeutic effect of safe, noninvasive, and brain-targeted intranasal administration of hair follicle-derived stem cells (HFSCs) in a rat model of ischemic stroke.

METHODS

Stem cells were obtained from the adult rat hair follicles. In experiment 1, stroke was induced by 30 min middle cerebral artery occlusion (MCAO) and stem cells were intranasally transplanted immediately after ischemia. In experiment 2, stroke was induced by 120 min MCAO and stem cells were administered 24 h after cerebral ischemia. In all experimental groups, neurological performance, short-term spatial working memory and infarct volume were assessed. Moreover, relative expression of major trophic factors in the striatum and cortex was evaluated by the quantitative PCR technique. The end point of experiment 1 was day 3 and the end point of experiment 2 was day 15.

RESULTS

In both experiments, intranasal administration of HFSCs improved functional performance and decreased infarct volume compared to the MCAO rats. Furthermore, NeuN and VEGF expression were higher in the transplanted group and stem cell therapy partially prevented BDNF and neurotrophin-3 over-expression induced by cerebral ischemia.

CONCLUSIONS

These findings highlight the curative potential of HFSCs following intranasal transplantation in a rat model of ischemic stroke.

Gene-Modified Stem Cells for Spinal Cord Injury: a Promising Better Alternative Therapy

Stem cell therapy holds great promise for the treatment of spinal cord injury (SCI), which can reverse neurodegeneration and promote tissue regeneration via its pluripotency and ability to secrete neurotrophic factors. Although various stem cell-based approaches have shown certain therapeutic effects when applied to the treatment of SCI, their clinical efficacies have been disappointing. Thus, it is an urgent need to further enhance the neurological benefits of stem cells through bioengineering strategies including genetic engineering. In this review, we summarize the progress of stem cell therapy for SCI and the prospect of genetically modified stem cells, focusing on the genome editing tools and functional molecules involved in SCI repair, trying to provide a deeper understanding of genetically modified stem cell therapy and more applicable clinical strategies for SCI repair.

Derivation of Stem Cell-like Cells From Spherical Culture of Astrocytes for Enhanced Neural Repair After Middle Cerebral Artery Occlusion

Neural precursor cells (NPCs) tend to aggregate and develop into three-dimensional (3D) spheres, which in turn help maintain the stemness of the cells. This close relationship between spherical environments and cell stemness direct us to assume that 3D spheres of astrocytes (ASTs) may facilitate the acquisition of stem cell-like features and generate sufficient seed cells for the regeneration of neurons. In vitro results confirmed that mouse ASTs cultured on agarose surfaces spontaneously formed cell spheres and exhibited molecular features similar to stem cells, particularly capable of further differentiating into neurons and forming functional synaptic networks with synchronous burst activities. RNA-sequencing results revealed the similarity between AST-derived stem cells (A-iSCs) and NPCs in global gene expression profiles. The potency of A-iSCs in repairing neural injuries was evaluated in a mouse model of middle cerebral artery occlusion. It was observed that the transplanted A-iSCs expressed a series of markers related to neural differentiation, such as NeuN, Tuj1, and Map2, indicating the conversion of the transplanted A-iSCs into neurons in the scenario. We also found that the injured mice injected with A-iSCs exhibited significant improvements in sensorimotor functions after 8 weeks compared with the sham and control mice. Taken together, mouse ASTs form cell spheres on agarose surfaces and acquire stem cell-associated features; meanwhile, the derived A-iSCs possess the capacity to differentiate into neurons and facilitate the regeneration of damaged nerves.

Developing Novel Therapies for Degenerative Cervical Myelopathy [AO Spine RECODE-DCM Research Priority Number 7]: Opportunities From Restorative Neurobiology

STUDY DESIGN

Narrative review.

OBJECTIVES

To provide an overview of contemporary therapies for the James Lind Alliance priority setting partnership for degenerative cervical myelopathy (DCM) question: 'Can novel therapies, including stem-cell, gene, pharmacological and neuroprotective therapies, be identified to improve the health and wellbeing of people living with DCM and slow down disease progression?'

METHODS

A review of the literature was conducted to outline the pathophysiology of DCM and present contemporary therapies that may hold therapeutic value in 3 broad categories of neuroprotection, neuroregeneration, and neuromodulation.

RESULTS

Chronic spinal cord compression leads to ischaemia, neuroinflammation, demyelination, and neuronal loss. Surgical intervention may halt progression and improve symptoms, though the majority do not make a full recovery leading to lifelong disability. Neuroprotective agents disrupt deleterious secondary injury pathways, and one agent, Riluzole, has undergone Phase-III investigation in DCM. Although it did not show efficacy on the primary outcome modified Japanese Orthopaedic Association scale, it showed promising results in pain reduction. Regenerative approaches are in the early stage, with one agent, Ibudilast, currently in a phase-III investigation. Neuromodulation approaches aim to therapeutically alter the state of spinal cord excitation by electrical stimulation with a variety of approaches. Case studies using electrical neuromuscular and spinal cord stimulation have shown positive therapeutic utility.

CONCLUSION

There is limited research into interventions in the 3 broad areas of neuroprotection, neuroregeneration, and neuromodulation for DCM. Contemporary and novel therapies for DCM are now a top 10 priority, and whilst research in these areas is limited in DCM, it is hoped that this review will encourage research into this priority.

Hyaluronic acid-based hydrogels loaded with chemoattractant and anticancer drug - new formulation for attracting and tackling glioma cells

Over the last few years, significant interest has emerged in the development of localised therapeutic strategies for the treatment of glioblastoma (GBM). The concept of attracting and trapping residual tumour cells within a confined area to facilitate their eradication has developed progressively. Herein, we propose a new design of hyaluronic acid-based hydrogel which can be utilized as a matrix containing a soluble chemoattractant to attract residual glioma cells and chemotherapeutic agents to eradicate them in a less invasive and more efficient way compared to the currently available methods. Hydrogels were prepared at different crosslinking densities, e.g. low and high density, by crosslinking hyaluronic acid with various concentrations of adipic acid dihydrazide and U87MG GBM cell morphology, survival and CD44 expression were evaluated. As a proof-of-concept, hydrogels were loaded with a small peptide chemokine, human urotensin II (hUII), and the migration and survival of U87MG GBM cells were studied. Chemoattractant-containing hydrogels were also loaded with chemotherapeutic drugs to promote cell death in culture. The results showed that U87MG cells were able to invade the hydrogel network and to migrate in response to the chemoattractant hUII. In addition, in static condition, hydrogels loaded with doxorubicin demonstrated significant cytotoxicity leading to less than 80% U87MG cell viability after 48 hours when compared to the control sample. In addition, in in vitro invasive assays, it was originally shown that the chemoattractant effect of hUII can be effective before the cytotoxic action of doxorubicin on the U87MG cells trapped in the hydrogel. Our results provide new insights into a promising approach which can be readily translated in vivo for the treatment of one of the most devastating brain tumours.

Aspirin impacts on stem cells: Implications for therapeutic targets

Despite the regenerative potential of stem cell therapy in pre-clinical investigations, clinical translation of cell-based therapy has not been completely clarified. In recent years, the importance of lifestyle, patient comorbidities, and prescribed medication has attracted more attention in the efficacy of cell therapy. As a nonsteroidal anti-inflammatory drug, aspirin is one of the most prevalent prescribed medications in the clinic for various disorders. Hence, aspirin treatment might affect the efficacy of stem cell therapy. In this regard, the current review focused on the impacts of aspirin on the viability, proliferation, differentiation, and immunomodulatory properties of stem cells in vitro as well as in experimental animal models.

Spinal Cord Injury Management through the Combination of Stem Cells and Implantable 3D Bioprinted Platforms

Spinal cord injury (SCI) has a major impact on affected patients due to its pathological consequences and absence of capacity for self-repair. Currently available therapies are unable to restore lost neural functions. Thus, there is a pressing need to develop novel treatments that will promote functional repair after SCI. Several experimental approaches have been explored to tackle SCI, including the combination of stem cells and 3D bioprinting. Implanted multipotent stem cells with self-renewing capacity and the ability to differentiate to a diversity of cell types are promising candidates for replacing dead cells in injured sites and restoring disrupted neural circuits. However, implanted stem cells need protection from the inflammatory agents in the injured area and support to guide them to appropriate differentiation. Not only are 3D bioprinted scaffolds able to protect stem cells, but they can also promote their differentiation and functional integration at the site of injury. In this review, we showcase some recent advances in the use of stem cells for the treatment of SCI, different types of 3D bioprinting methods, and the combined application of stem cells and 3D bioprinting technique for effective repair of SCI.

The Beneficial Potential of Genetically Modified Stem Cells in the Treatment of Stroke: a Review

The last two decades have witnessed a surge in investigations proposing stem cells as a promising strategy to treat stroke. Since growth factor release is considered as one of the most important aspects of cell-based therapy, stem cells over-expressing growth factors are hypothesized to yield higher levels of therapeutic efficiency. In pre-clinical studies of the last 15 years that were investigating the efficiency of stem cell therapy for stroke, a variety of stem cell types were genetically modified to over-express various factors. In this review we summarize the current knowledge on the therapeutic efficiency of stem cell-derived growth factors, encompassing techniques employed and time points to evaluate. In addition, we discuss several types of stem cells, including the recently developed model of epidermal neural crest stem cells, and genetically modified stem cells over-expressing specific factors, which could elevate the restorative potential of naive stem cells. The restorative potential is based on enhanced survival/differentiation potential of transplanted cells, apoptosis inhibition, infarct volume reduction, neovascularization or functional improvement. Since the majority of studies have focused on the short-term curative effects of genetically engineered stem cells, we emphasize the need to address their long-term impact.

The Implementation of Preconditioned Epidermal Neural Crest Stem Cells to Combat Ischemic Stroke. Comment on Othman, F.A.; Tan, S.C. Preconditioning Strategies to Enhance Neural Stem Cell-Based Therapy for Ischemic Stroke. Brain Sci. 2020, 10, 893

In the recent review published in Brain Sciences, Othman and Tan suggested several preconditioning strategies to improve stem cell therapy after ischemic brain injury [...].

Mesenchymal stem cell conditioned medium increases glial reactivity and decreases neuronal survival in spinal cord slice cultures

Ex vivo spinal cord slice cultures (SCSC) allow study of spinal cord circuitry, maintaining stimuli responses comparable to live animals. Previously, we have shown that mesenchymal stem/stromal cell (MSC) transplantation in vivo reduced inflammation and increased nerve regeneration but MSC survival was short-lived, highlighting that beneficial action may derive from the secretome. Previous in vitro studies of MSC conditioned medium (CM) have also shown increased neuronal growth. In this study, murine SCSC were cultured in canine MSC CM (harvested from the adipose tissue of excised inguinal fat) and cell phenotypes analysed via immunohistochemistry and confocal microscopy. SCSC in MSC CM displayed enhanced viability after propidium iodide staining. GFAP immunoreactivity was significantly increased in SCSC in MSC CM compared to controls, but with no change in proteoglycan (NG2) immunoreactivity. In contrast, culture in MSC CM significantly decreased the prevalence of βIII-tubulin immunoreactive neurites, whilst Ca²⁺ transients per cell were significantly increased. These ex vivo results contradict previous in vitro and in vivo reports of how MSC and their secretome may affect the microenvironment of the spinal cord after injury and highlight the importance of a careful comparison of the different experimental conditions used to assess the potential of cell therapies for the treatment of spinal cord injury.

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Treatment of spinal slices with conditioned medium caused cell phenotypic changes.

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Resident astrocytes become hypertrophic, yet neuronal axonal outgrowth reduced.

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Signalling cells reduced in number but increased their signalling activity.

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Highlights importance of simulation systems and systemic factors in CNS models.

Neural crest-like stem cells for tissue regeneration

Neural crest stem cells (NCSCs) are a transient population of cells that arise during early vertebrate development and harbor stem cell properties, such as self‐renewal and multipotency. These cells form at the interface of non‐neuronal ectoderm and neural tube and undergo extensive migration whereupon they contribute to a diverse array of cell and tissue derivatives, ranging from craniofacial tissues to cells of the peripheral nervous system. Neural crest‐like stem cells (NCLSCs) can be derived from pluripotent stem cells, placental tissues, adult tissues, and somatic cell reprogramming. NCLSCs have a differentiation capability similar to NCSCs, and possess great potential for regenerative medicine applications. In this review, we present recent developments on the various approaches to derive NCLSCs and the therapeutic application of these cells for tissue regeneration.

Human Dental Pulp Stem Cells Display a Potential for Modeling Alzheimer Disease-Related Tau Modifications

We present here the first description of tau in human dental pulp stem cells (DPSCs) evidenced by RT-PCR data on expression of the gene MAPT and by immunocytochemical detection of epitopes by 12 anti-tau antibodies. The tau specificity of eight of these antibodies was confirmed by their affinity to neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) postmortem brain samples. We therefore used DPSCs and AD brain samples as a test system for determining the probability of the involvement of tau epitopes in the mechanisms converting tau into NFT in AD. Three antibodies to non-phosphorylated and seven antibodies to phosphorylated epitopes bound tau in both DPSCs and AD NFTs, thus suggesting that their function was not influenced by inducers of formation of NFTs in the AD brain. In contrast, AT100, which recognizes a hyperphosphorylated epitope, did not detect it in the cytoplasm of DPSCs but detected it in AD brain NFTs, demonstrating its AD diagnostic potential. This indicated that the phosphorylation/conformational events required for the creation of this epitope do not occur in normal cytoplasm and are a part of the mechanism (s) leading to NFT in AD brain. TG3 bound tau in the cytoplasm and in mitotic chromosomes but did not find it in nuclei. Collectively, these observations characterize DPSCs as a novel tau-harboring neuronal lineage long-term propagable in vitro cellular system for the normal conformational state of tau sites, detectable by antibodies, with their state in AD NFTs revealing those involved in the pathological processes converting tau into NFTs in the course of AD. With this information, one can model the interaction of tau with inducers and inhibitors of hyperphosphorylation toward NFT-like aggregates to search for drug candidates. Additionally, the clonogenicity of DPSCs provides the option for generation of cell lineages with CRISPR-mutagenized genes of familial AD modeling.

Enhanced Neural Differentiation of Epidermal Neural Crest Stem Cell by Synergistic Effect of Lithium carbonate and Crocin on BDNF and GDNF Expression as Neurotrophic Factors

Neurodegenerative diseases are incurable and debilitating conditions that result in progressive degeneration of nerve cells. Due to the complexity of conditions in neurodegenerative diseases, combination therapy, including cell and drug therapy is important as a new therapeutic strategy. Epidermal neural crest stem cells (EPI-NCSCs) are among the best choices in cell therapy for various neurological diseases. In this study, the effect of Lithium carbonate and Crocin, considering their effects on cellular signaling pathways and neuroprotective properties were investigated on the expression of neurotrophic factors BDNF and GDNF in EPI-NCSCs. EPI-NCSCs were isolated from the hair follicle and treated with different concentrations of drugs [Lithium, Crocin, and lithium + Crocin] for 72h. Then, trial concentrations were selected by MTT assay. The cells were treated with selected concentrations (Lithium 1 mM, Crocin 1.5 mM, and for co-treatment Lithium 1 mM and Crocin 1 mM) for 7 days. The Real-Time PCR results indicated an increasing in expression of BDNF and GDNF in treated cells as compared with control (* p < 0.05, ** p < 0.01 and *** p < 0.001). The results in this study confirmed and supported the neuroprotective/neurogenesis effects of Lithium and Crocin. It also showed that the proposed protocol could be used to increase EPI-NCSCs differentiation potential into neural cells in cell therapy and combination therapy of neurodegenerative diseases.

Progress in Stem Cell Therapy for Spinal Cord Injury

Background

Spinal cord injury (SCI) is one of the serious neurological diseases that occur in young people with high morbidity and disability. However, there is still a lack of effective treatments for it. Stem cell (SC) treatment of SCI has gradually become a new research hotspot over the past decades. This article is aimed at reviewing the research progress of SC therapy for SCI.

Methods

Review the literature and summarize the effects, strategies, related mechanisms, safety, and clinical application of different SC types and new approaches in combination with SC in SCI treatment.

Results

A large number of studies have focused on SC therapy for SCI, most of which showed good effects. The common SC types for SCI treatment include mesenchymal stem cells (MSCs), hematopoietic stem cells (HSCs), neural stem cells (NSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs). The modes of treatment include in vivo and in vitro induction. The pathways of transplantation consist of intravenous, transarterial, nasal, intraperitoneal, intrathecal, and intramedullary injections. Most of the SC treatments for SCI use a number of cells ranging from tens of thousands to millions. Early or late SC administration, application of immunosuppressant or not are still controversies. Potential mechanisms of SC therapy include tissue repair and replacement, neurotrophy, and regeneration and promotion of angiogenesis, antiapoptosis, and anti-inflammatory. Common safety issues include thrombosis and embolism, tumorigenicity and instability, infection, high fever, and even death. Recently, some new approaches, such as the pharmacological activation of endogenous SCs, biomaterials, 3D print, and optogenetics, have been also developed, which greatly improved the application of SC therapy for SCI.

Conclusion

Most studies support the effects of SC therapy on SCI, while a few studies do not. The cell types, mechanisms, and strategies of SC therapy for SCI are very different among studies. In addition, the safety cannot be ignored, and more clinical trials are required. The application of new technology will promote SC therapy of SCI.

Hydrogel and neural progenitor cell delivery supports organotypic fetal spinal cord development in an ex vivo model of prenatal spina bifida repair

Studying how the fetal spinal cord regenerates in an ex vivo model of spina bifida repair may provide insights into the development of new tissue engineering treatment strategies to better optimize neurologic function in affected patients. Here, we developed hydrogel surgical patches designed for prenatal repair of myelomeningocele defects and demonstrated viability of both human and rat neural progenitor donor cells within this three-dimensional scaffold microenvironment. We then established an organotypic slice culture model using transverse lumbar spinal cord slices harvested from retinoic acid–exposed fetal rats to study the effect of fibrin hydrogel patches ex vivo. Based on histology, immunohistochemistry, gene expression, and enzyme-linked immunoabsorbent assays, these experiments demonstrate the biocompatibility of fibrin hydrogel patches on the fetal spinal cord and suggest this organotypic slice culture system as a useful platform for evaluating mechanisms of damage and repair in children with neural tube defects.

Current advances in in vitro models of central nervous system trauma

CNS trauma is a prominent cause of mortality and morbidity, and although much effort has focused on developing treatments for CNS trauma-related pathologies, little progress has been made. Pre-clinical models of TBI and SCI suffer from significant drawbacks, which result in substantial failures during clinical translation of promising pre-clinical therapies. Here, we review recent advances made in the development of in vitro models of CNS trauma, the promises and drawbacks of current in vitro CNS injury models, and the attributes necessary for future models to accurately mimic the trauma microenvironment and facilitate CNS trauma drug discovery. The goal is to provide insight for the development of future CNS injury models and to aid researchers in selecting effective models for pre-clinical research of trauma therapeutics.

Epidermal neural crest stem cell transplantation as a promising therapeutic strategy for ischemic stroke

Introduction

Cell‐based therapy is considered as promising strategy to cure stroke. However, employing appropriate type of stem cell to fulfill many therapeutic needs of cerebral ischemia is still challenging. In this regard, the current study was designed to elucidate therapeutic potential of epidermal neural crest stem cells (EPI‐NCSCs) compared to bone marrow mesenchymal stem cells (BM‐MSCs) in rat model of ischemic stroke.

Methods

Ischemic stroke was induced by middle cerebral artery occlusion (MCAO) for 45 minutes. Immediately after reperfusion, EPI‐NCSCs or BM‐MSCs were transplanted via intra‐arterial or intravenous route. A test for neurological function was performed before ischemia and 1, 3, and 7 days after MCAO. Also, infarct volume ratio and relative expression of 15 selected target genes were evaluated 7 days after transplantation.

Results

EPI‐NCSCs transplantation (both intra‐arterial and intravenous) and BM‐MSCs transplantation (only intra‐arterial) tended to result in a better functional outcome, compared to the MCAO group; however, this difference was not statistically significant. The infarct volume ratio significantly decreased in NCSC‐intra‐arterial, NCSC‐intravenous and MSC‐intra‐arterial groups compared to the control. EPI‐NCSCs interventions led to higher expression levels of Bdnf, nestin, Sox10, doublecortin, β‐III tubulin, Gfap, and interleukin‐6, whereas neurotrophin‐3 and interleukin‐10 were decreased. On the other hand, BM‐MSCs therapy resulted in upregulation of Gdnf, β‐III tubulin, and Gfap and down‐regulation of neurotrophin‐3, interleukin‐1, and interleukin‐10.

Conclusion

These findings highlight the therapeutic effects of EPI‐NCSCs transplantation, probably through simultaneous induction of neuronal and glial formation, as well as Bdnf over‐expression in a rat model of ischemic stroke.

Substrate stiffness affects the morphology and gene expression of epidermal neural crest stem cells in a short term culture

According to the intrinsic plasticity of stem cells, controlling their fate is a critical issue in cell-based therapies. Recently, a growing body of evidence has suggested that substrate stiffness can affect the fate decisions of various stem cells. Epidermal neural crest stem cells as one of the main neural crest cell derivatives hold great promise for cell therapies due to presenting a high level of plasticity. This study was conducted to define the influence of substrate stiffness on the lineage commitment of these cells. Here, four different polyacrylamide hydrogels with elastic modulus in the range of 0.7-30 kPa were synthesized and coated with collagen and stem cells were seeded on them for 24 hr. The obtained data showed that cells can attach faster to hydrogels compared with culture plate and cells on <1 kPa stiffness show more neuronal-like morphology as they presented several branches and extended longer neurites over time. Moreover, the transcription of actin downregulated on all hydrogels, while the expression of Nestin, Tubulin, and PDGFR-α increased on all of them and SOX-10 and doublecortin gene expression were higher only on <1 kPa. Also, it was revealed that soft hydrogels can enhance the expression of glial cell line-derived neurotrophic factor, neurotrophin-3, and vascular endothelial growth factor in these stem cells. On the basis of the results, these cells can respond to the substrate stiffness in the short term culture and soft hydrogels can alter their morphology and gene expression. These findings suggested that employing proper substrate stiffness might result in cells with more natural profiles similar to the nervous system and superior usefulness in therapeutic applications.

Enhancing the expression of neurotrophic factors in epidermal neural crest stem cells by valproic acid: A potential candidate for combinatorial treatment

Effective delivery of trophic factors to cure neurological disorders and traumatic injuries is a major challenge. With promising therapeutic effects of epidermal neural crest stem cells (EPI-NCSCs) in preclinical spinal cord injury, there is an implication that these stem cells might provide supportive role through releasing various trophic agents. Hence, the present study was designed to assess the influence of valproic acid (VPA), a well-known histone deacetylases inhibitor, on mRNA expression of selected trophic factors. In this study, following stem cell migration from explanted hair bulges, immunostaining against Nestin, SOX-10, DCX, β-III tubulin and GFAP was carried out. Then, cells were treated with various clinically relevant concentrations of VPA and the survival rate was defined by MTT assay. Finally, stem cells were treated with 0.1 and 1 mM VPA and the drug impact on the transcription level of BDNF, GDNF, VEGF, NGF and NT3 at 6, 24, 72, 168 h was assessed by quantitative real-time PCR. The examined proteins expressions in the population of migrated cells confirmed the identity of stem cells as EPI-NCSCs. In addition, MTT assay showed that all three tested concentrations of VPA were suitable to treat these cells. Trophic factors assessment, following treatment revealed the mRNA expression level of BDNF, GDNF and VEGF could be significantly up- regulated at various time points, mainly by 1 mM VPA. However, NGF and NT3 transcripts were enhanced at few limited time points. Our findings showed that EPI-NCSCs due to secretion of various trophic factors are potential candidate to deliver the required trophic agents and their potential can be enhanced by 1 mM VPA, predominantly following 168 h treatment. Hence, these cells can be utilized to modulate destructive context of neurological disorders and injuries.

Dimethyl fumarate up-regulates expression of major neurotrophic factors in the epidermal neural crest stem cells

There is an agreement that combining treatments can lead to substantial improvement, therefore the present study assessed the effects of different concentrations of dimethyl fumarate (DMF) on viability of epidermal neural crest stem cells (EPI-NCSCs). In addition, this investigation was designed to evaluate the effects of DMF on relative expression of major trophic factors mainly the ones with neurotrophic effects, expressed in EPI-NCSCs in order to enhance their therapeutic potential. To determine the appropriate concentration of DMF for EPI-NCSCs treatment, the MTT assay was employed and based on the obtained data, EPI-NCSCs treated with 10μM DMF for 6, 24, 72 or 168 h. In each time point, quantitative RT-PCR technique was used to evaluate NGF, NT-3, BDNF, GDNF and VEGF transcripts. The acquired data showed that 10μM DMF significantly increased the mRNA expression of NGF, NT-3 and BDNF, 72 h following treatment; however, DMF inhibitory effect on GDNF mRNA expression was observed in various time points. No significant changes were detected for VEGF transcript. Our findings reveled that expression of major neurotrophic factors were up-regulated by dimethyl fumarate treatment. Therefore, combining EPI-NCSCs with DMF treatment might be a valuable strategy to improve their therapeutic functions in vivo.

Postnatal neural crest stem cells from hair follicle interact with nerve tissue in vitro and in vivo

Neural crest stem cells that located in the postnatal hair follicle (HF-NCSC) are considered a promising tool for treatment of nervous system diseases and injuries. It is well known that HF-NCSC can be used in the spinal cord and sciatic nerve reparation but their ability to restore brain structures is poorly studied. In this article we are investigating the interaction between HF-NCSC and a nerve tissue (embryonic and adult). We have found out that HF-NCSC isolated from adult mice grow and differentiate in accordance with the mouse embryo developmental stage when co-cultured with the embryonic nerve tissue. The HF-NCSC migration is slower in the late embryonic tissue co-culture system compared to the early one. This phenomenon is related to the motor function of the cells but not to their proliferation level. We have demonstrated that the embryonic nerve tissue maintains HF-NCSC an undifferentiated status, while an adult brain tissue inhibits the cell proliferation and activates the differentiation processes. Besides, HF-NCSC pre-differentiated into the neuronal direction shows a higher survival and migration rate after the transplantation into the adult brain tissue compared to the undifferentiated HF-NCSC. Thus, we have investigated the postnatal HF-NCSC response to the nerve tissue microenvironment to analyze their possible application to the brain repair processes.