Gens PSD-95 and GSK-3β expression improved by hair follicular stem cells-conditioned medium enhances synaptic transmission and cognitive abilities in the rat model of vascular dementia

INTRODUCTION

Vascular dementia (VaD) is a common type of dementia. The aim of this study was to investigate the cellular and molecular mechanism of conditioned medium (CM) in VaD.

MATERIAL AND METHODS

The rats were divided into four groups of control (n = 9), sham-operation (n = 10), VaD with vehicle (n = 9), and VaD with CM (n = 12) that received CM on days 4, 14, and 24 after 2VO. Before sacrificing the rats, cognitive performance was assessed through the open-field (OP), passive-avoidance, and Morris-water maze. The field-potential recording was used to investigate basal synaptic transmission (BST) and long-term potentiation (LTP). Subsequently, the hippocampus was dissected, and real-time PCR was used to quantify the expression levels of β1-catenin, insulin-like growth factor-1 (IGF-1), transforming growth factor-beta (TGF-β), glycogen synthase kinase-3β (GSK-3β), postsynaptic density protein 95 (PSD-95), and NR2B genes.

RESULTS

The results indicated impaired performance in behavioral tests in 2VO rats, coupled with reductions in BST and LTP induction. The expression levels of β1-catenin, IGF-1, PSD-95, and TGF-β genes decreased, whereas NR2B and GSK-3β expression increased. Treatment with CM restores the expression of PSD-95 and GSK-3β as well as fear-memory, spatial learning, and grooming number without a positive effect on memory retrieval, time spent on the periphery and center of OP. The BST recovered upon administration of CM but, the LTP induction was still impaired.

CONCLUSION

The recovery of BST in VaD rats appears to be the most important outcome of this study which is caused by the improvement of gene expression and leads to the restoration of fear memory.

Combination Therapy with Platelet-Rich Plasma and Epidermal Neural Crest Stem Cells Increases Treatment Efficacy in Vascular Dementia

This study aimed to evaluate the efficacy and treatment mechanism of platelet-rich plasma (PRP) and neural crest-derived epidermal stem cells (ESCs) in their administration alone and combination in vascular dementia (VaD) model by two-vessel occlusion (2VO). Methods. Sixty-six rats were divided into six groups: the control, sham, 2VO + vehicle, 2VO + PRP, 2VO + ESC, and 2VO + ESC + PRP. The treated groups received 1 million cells on days 4, 14, and 21 with or without 500 µl PRP (twice a week) after 2VO. The memory performance and anxiety were evaluated by behavioral tests including open field, passive avoidance, and Morris water maze. The basal-synaptic transmission (BST) and long-term potentiation (LTP) were assessed through field-potential recordings of the CA1. The mRNA expression levels of IGF-1, TGF-β1, PSD-95, and GSk-3β were measured in the rat hippocampus by quantitative reverse transcription polymerase chain reaction. Results. The results demonstrated impaired learning, memory, and synaptic plasticity in the 2VO rats, along with a significant decrease in the expression of IGF-1, TGF-β1, PSD-95, and upregulation of GSK-3β. Treatment with ESC alone and ESC + PRP showed similar improvements in spatial memory and LTP induction, with associated upregulation of PSD-95 and downregulation of GSK-3β. However, only the ESC + PRP group showed recovery in BST. Furthermore, combination therapy was more effective than PRP monotherapy for LTP and memory. Conclusions. The transplantation of ESC showed better effects than PRP alone, and combination therapy increased the treatment efficacy with the recovery of BST. This finding may be a clue for the combination therapy of ESC and PRP for VaD.

Simple methods for cerebrospinal fluid collection in fetal, neonatal, and adult rat

BACKGROUND

Cerebrospinal fluid (CSF) collection and its analysis are common medical practices useful in the diagnosis, therapy, and prevention of central nervous system (CNS) disorders. In recent years, several types of research have improved our insight into CSF and its role in health and disease. Yet, many characteristics of this fluid remain to be fully understood.

NEW METHODS

Here, we describe how to collect CSF from embryonic, postnatal, and adult stages of the rat. In adults, CSF can be collected through simple stereotaxic surgery to expose the membrane overlying the cisterna magna (CM) of an anesthetized rat and collection of CSF through micropipette puncture through the membrane. In embryos and pups, CSF is aspirated, using a fire-polished micro-capillary pipette, from the CM of animals.

RESULTS

Application of these methods provides the maximum volume of pure, uncontaminated CSF (embryonic day 19: 10-15 microliter, postnatal day 5: 20-30 microliter, adults: 100-200 microliter) with a success rate of approximately 95% in every age.

COMPARISON WITH EXISTING METHODS

Compared to the existing protocols, these methods obtain considerable volumes of CSF, which may accelerate the measurement of biological markers in this fluid. Also, these techniques do not require surgical skills and according to the practical points mentioned during sampling, the procedures can be performed in rapid fashion.

CONCLUSION

We describe simple methods for collecting CSF in live rats. These protocols provide clean, uncontaminated CSF for experiments to understand the exact role of this fluid in the development and maintenance of the CNS health.

Combined use of hair follicle stem cells and CEPO (carbamylated erythropoietin)-Fc in a rat model of chronic cerebral hypoperfusion: A behavioral, electrophysiological, and molecular study

BACKGROUND

In dementia, synaptic dysfunction appears before neuronal loss. Stem cell therapy could potentially provide a promising strategy for the treatment of dementia models. The carbamylated erythropoietin fusion protein (CEPO-Fc) has shown synaptotrophic effects. This study aimed to determine the efficiency of the combined use of hair follicle stem cells (HFSC) and CEPO-Fc in the basal synaptic transmission (BST) and long-term plasticity (LTP) of chronic cerebral hypoperfusion (CCH) rats.

METHODS

We divided 64 adult rats into control, sham, CCH+vehicle, CCH+CEPO, CCH+HFSC, and CCH+HFSC+CEPO groups. The CEPO-Fc was injected three times/week for 30 days. HFSC transplantation was done on days 4, 14, and 21 after surgery. The Morris water maze test and passive avoidance were used to assess memory. BST and LTP were assessed by a field-potential recording of the CA1 region. The hippocampal mRNA expression of IGF-1, TGF-β1, β1-Catenine, NR2B, PSD-95, and GSk-3β was evaluated by quantitative RT-PCR.

RESULTS

Following combination therapy, spatial memory retention, and BST showed significant improvement relative to HFSC and CEPO-Fc groups. These effects were also confirmed by recovered mRNA expression of β1-catenin, TGF-β1, and NR2B. GSK-3β expression was downregulated in all treatment groups. The upregulated PSD-95 was identified in HFSC and combination groups compared to the vehicle group.

CONCLUSIONS

These findings indicate that the combined use of HFSC and CEPO-Fc may be more advantageous for treating memory disruption in the CCH model than CEPO-Fc or HFSC alone. This type of combination therapy may hopefully lead to a new approach to treatment for dementia.

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.

Short-term beneficial effects of human dental pulp stem cells and their secretome in a rat model of mild ischemic stroke

Although cell therapy has been applied in regenerative medicine for decades, recent years have seen greatly increased attention being given to the use of stem cell-based derivatives such as cell-free secretome. Dental pulp stem cells (DPSCs) are widely available, easily accessible, and have high neuroprotective and angiogenic properties. In addition, DPSC-derived secretome contains a rich mixture of trophic factors. The current investigation evaluated the short-term therapeutic effects of human DPSCs and their secretome in a rat model of mild ischemic stroke. Mild ischemic stroke was induced by 30 min middle cerebral artery occlusion, and hDPSCs or their secretome was administered intra-arterially and intranasally. Neurological function, infarct size, spatial working memory, and relative expression of seven target genes in two categories of neurotrophic and angiogenic factors were assessed three days after stroke. In the short-term, all treatments reduced the severity of neurological and histological deficits caused by ischemic stroke. Moreover, transient middle cerebral artery occlusion led to the striatal and cortical over-expression of BDNF, NT-3, and angiogenin, while NGF and VEGF expression was reduced. Almost all interventions were able to modulate the expression of target genes after stroke. The obtained data revealed that single intra-arterial administration of hDPSCs or their secretome, single intranasal transplantation of hDPSCs, or repeated intranasal administration of hDPSC-derived secretome was able to ameliorate the devastating effects of a mild stroke, at least in the short-term.

From Hair to the Brain: The Short-Term Therapeutic Potential of Human Hair Follicle-Derived Stem Cells and Their Conditioned Medium in a Rat Model of Stroke

The short-term therapeutic impacts of stem cells and their derivatives were frequently reported in preclinical investigations of ischemic stroke (IS); however, several drawbacks including accessibility, abundancy, and ethical concerns limited their clinical application. We describe here for the first time the therapeutic potential of human hair follicle-derived stem cells (hHFSCs) and their conditioned medium (CM) in a rat model of IS. Furthermore, we hypothesized that a combination of cell therapy with repeated CM administration might enhance the restorative efficiency of this approach compared to each treatment alone. Middle cerebral artery occlusion was performed for 30 min to induce IS. Immediately after reperfusion, hHFSCs were transplanted through the intra-arterial route and/or hHFSC-CM administered intranasally. The neurological outcomes, short-term spatial working memory, and infarct size were evaluated. Furthermore, relative expression of seven target genes in three categories of neuronal markers, synaptic markers, and angiogenic markers was assessed. The hHFSCs and hHFSC-CM treatments improved neurological impairments and reduced infarct size in the IS rats. Moreover, molecular data elucidated that IS was accompanied by attenuation in the expression of neuronal and synaptic markers in the evaluated brain regions and the interventions rescued these expression changes. Although there was no considerable difference between hHFSCs and hHFSC-CM treatments in the improvement of neurological function and decrement of infarct size, combination therapy was more effective to reduce infarction and elevation of target gene expression especially in the hippocampus. These findings highlight the curative potential of hHFSCs and their CM in a rat model of IS.

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.

Oxytocin accelerates tight junction formation and impairs cellular migration in 3D spheroids: evidence from Gapmer-induced exon skipping

Oxytocin (OXT) is a neuropeptide that has been associated with neurological diseases like autism, a strong regulating activity on anxiety and stress-related behavior, physiological effects during pregnancy and parenting, and various cellular effects in neoplastic tissue. In this study, we aimed to unravel the underlying mechanism that OXT employs to regulate cell-cell contacts, spheroid formation, and cellular migration in a 3D culture model of human MLS-402 cells. We have generated a labeled OXT receptor (OXTR) overexpressing cell line cultivated in spheroids that were treated with the OXTR agonists OXT, Atosiban, and Thr4-Gly7-oxytocin (TGOT); with or without a pre-treatment of antisense oligos (Gapmers) that induce exon skipping in the human OXTR gene. This exon skipping leads to the exclusion of exon 4 and therefore a receptor that lost its intracellular G-protein-binding domain. Sensitive digital PCR (dPCR) provided us with the means to differentiate between wild type and truncated OXTR in our cellular model. OXTR truncation differentially activated intracellular signaling cascades related to cell-cell attachment and proliferation like Akt, ERK1/2-RSK1/2, HSP27, STAT1/5, and CREB, as assessed by a Kinase Profiler Assay. Digital and transmission electron microscopy revealed increased tight junction formation and well-organized cellular protrusions into an enlarged extracellular space after OXT treatment, resulting in increased cellular survival. In summary, OXT decreases cellular migration but increases cell-cell contacts and therefore improves nutrient supply. These data reveal a novel cellular effect of OXT that might have implications for degenerating CNS diseases and tumor formation in various tissues.

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.

Reproductive complications after stroke: long-lasting impairment of GnRH neuronal network?

Some studies have demonstrated that stroke may increase the risk of pregnancy complications and early menopause. In addition, preclinical investigations revealed the middle cerebral artery occlusion could affect hypothalamus. Since hypothalamus is the core of central circuits regulating reproductive processes, impairment of hypothalamic GnRH neuronal network following stroke might be manifested in long-lasting reproductive disorders.

Intranasal application of stem cells and their derivatives as a new hope in the treatment of cerebral hypoxia/ischemia: a review

Intranasal delivery of stem cells and conditioned medium to target the brain has attracted major interest in the field of regenerative medicine. In pre-clinical investigations during the last ten years, several research groups focused on this strategy to treat cerebral hypoxia/ischemia in neonates as well as adults. In this review, we discuss the curative potential of stem cells, stem cell derivatives, and their delivery route via intranasal application to the hypoxic/ischemic brain. After intranasal application, stem cells migrate from the nasal cavity to the injured area and exert therapeutic effects by reducing brain tissue loss, enhancing endogenous neurogenesis, and modulating cerebral inflammation that leads to functional improvements. However, application of this administration route for delivering stem cells and/or therapeutic substances to the damaged sites requires further optimization to translate the findings of animal experiments to clinical trials.

Preconditioning with secretome of neural crest-derived stem cells enhanced neurotrophic expression in mesenchymal stem cells

During the last 20 years, stem cell therapy has been considered as an effective approach for regenerative medicine. Due to poor ability of stem cells to survive following transplantation, it has been proposed that beneficial effects of stem cells mainly depend on paracrine function. Therefore, the present study was designed to reinforce mesenchymal stem cells (MSCs) to express higher levels of trophic factors especially the ones with the neurotrophic properties. Here, bone marrow (BM)-MSCs and adipose-MSCs were treated with conditioned medium (CM) of dental pulp stem cells (DPSCs) or hair follicle stem cells (HFSCs) for up to three days. The relative expression of five key trophic factors that have critical effects on the central nervous system regeneration were evaluated using qRT-PCR technique. Furthermore, to assess the impacts of conditioned mediums on the fate of MSCs, expression of seven neuronal/glial markers were evaluated 3 days after the treatments. The obtained data revealed priming of BM-MSCs with HFSC-CM or DPSC-CM increases the BDNF expression over time. Such effect was also observed in adipose-MSCs following DPSC-CM treatment. Secretome preconditioning remarkably increased NGF expression in the adipose-MSCs. In addition, although priming of adipose-MSCs with HFSC-CM increased GDNF expression one day after the treatment, DPSC-CM enhanced GDNF mRNA in BM-MSCs at a later time point. It seemed priming of BM-MSCs with HFSC-CM, promoted differentiation into the glial lineage. Our findings showed that MSCs preconditioning with secretome of neural crest-derived stem cells could be a promising approach to enhance the neurotrophic potential of these stem cells.

Optogenetic stimulation of entorhinal cortex reveals the implication of insulin signaling in adult rat's hippocampal neurogenesis

Adult neurogenesis in the hippocampal dentate gyrus plays a critical role in learning and memory. Projections originating from entorhinal cortex, known as the perforant pathway, provide the main input to the dentate gyrus and promote neurogenesis. However, neuromodulators and molecular changes mediating neurogenic effects of this pathway are not yet fully understood. Here, by means of an optogenetic approach, we investigated neurogenesis and synaptic plasticity in the hippocampus of adult rats induced by stimulation of the perforant pathway. The lentiviruses carrying hChR2 (H134R)-mCherry gene under the control of the CaMKII promoter were injected into the medial entorhinal cortex region of adult rats. After 21 days, the entorhinal cortex region was exposed to the blue laser (473 nm) for five consecutive days (30 min/day). The expression of synaptic plasticity and neurogenesis markers in the hippocampus were evaluated using molecular and histological approaches. In parallel, the changes in the gene expression of insulin and its signaling pathway, trophic factors, and components of mitochondrial biogenesis were assessed. Our results showed that optogenetic stimulation of the entorhinal cortex promotes hippocampal neurogenesis and synaptic plasticity concomitant with the increased levels of insulin mRNA and its signaling markers, neurotrophic factors, and activation of mitochondrial biogenesis. These findings suggest that effects of perforant pathway stimulation on the hippocampus, at least in part, are mediated by insulin increase in the dentate gyrus and subsequently activation of its downstream signaling pathway.

The neuroprotective properties and therapeutic potential of epidermal neural crest stem cells transplantation in a rat model of vascular dementia

INTRODUCTION

The incidence rate of senile dementia is rising, and there is no definite cure for it yet. Cell therapy, as a new investigational approach, has shown promising results. Hair bulges with abundant easily accessible neural stem cells permit autologous implantation in irreversible neurodegenerative disorders.

METHODS

Fifty rats were randomly divided into 5 groups of control, sham-operation, two-common carotid vessel-occlusion rats that received vehicle (2VO + V), 2VO rats that received 1 × 10⁶ epidermal stem cells (2VO + ESC1), and 2VO rats that received 2.5 × 10⁶ epidermal stem cells (2VO + ESC2) in 300 µl PBS intravenously on days 4, 9, and 14 after surgery. The epidermal neural crest stem cells (EPI-NCSCs) were isolated from hair follicles of rat whiskers. The open-field, passive avoidance, and Morris water maze were used as behavioral tests. The basal-synaptic transmission, long-term potentiation (LTP), and short-term synaptic plasticity were evaluated by field-potential recording of the CA1 hippocampal area.

RESULTS

30 days after the first transplantation in the 2VO + ESC1 group, functional recovery was prominent in anxiety and fear memory compared to the 2VO + ESC2 group, while LTP induction was recovered in both groups of grafted animals without improvement in basal synaptic transmission. These positive recoveries may be related to the release of different neurotrophic factors from grafted cells that can stimulate endogenous neurogenesis and synaptic plasticity.

CONCLUSIONS

Our results showed that EPI-NCSCs implantation could rescue LTP and cognitive disability in 2VO rats, while transplantation of 1 million cells showed better performance relative to 2.5 million cells.

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.

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.

Experimental Models of SARS-CoV-2 Infection: Possible Platforms to Study COVID-19 Pathogenesis and Potential Treatments

In December 2019, a novel coronavirus crossed species barriers to infect humans and was effectively transmitted from person to person, leading including vaccines and antiviral drugs that could prevent or limit the burden or transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global health priority. It is thus of utmost importance to assess possible therapeutic strategies against SARS-CoV-2 using experimental models that recapitulate aspects of the human disease. Here, we review available models currently being developed and used to study SARS-CoV-2 infection and highlight their application to screen potential therapeutic approaches, including repurposed antiviral drugs and vaccines. Each identified model provides a valuable insight into SARS-CoV-2 cellular tropism, replication kinetics, and cell damage that could ultimately enhance understanding of SARS-CoV-2 pathogenesis and protective immunity. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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.

Investigating the synergic effects of valproic acid and crocin on BDNF and GDNF expression in epidermal neural crest stem cells

Following nerve tissue damage, various events, such as inflammatory responses, microglial activation, endoplasmic reticulum stress, and apoptosis, can occur, which all lead to cell death, prevent axonal growth, and cause axonal circumvolution. So far, several researchers have tended to adopt strategies to reduce the harmful conditions associated with neurological disorders, and stem‑cell‑based therapy is one of those promising strategies. Epidermal neural crest stem cells (EPI‑NCSCs) are a type of stem cell that has widely been employed for the treatment of various neurological disorders. It has been suggested that these stem cells perform their supportive actions primarily through the release of different neurotrophic factors. Hence, in this study, the neuroprotective impacts of valproic acid (VPA) and crocin were evaluated on the mRNA expression levels of brain‑derived neurotrophic factor (BDNF) and glial‑cell‑derived neurotrophic factor (GDNF) in EPI‑NCSCs. In this research, we isolated EPI‑NCSCs from the hair follicles of the rat whisker pad. Then, the cells were treated with different concentrations of VPA and crocin for 72 h. Subsequently, an MTT assay was performed to define the suitable concentrations of drugs. Finally, real‑time PCR was performed to evaluate the mRNA expression levels of BDNF and GDNF in these stem cells. The results of the MTT assay showed that the treatment of EPI‑NCSCs with 1 mM VPA and 1.5 mM crocin, and the co‑treatment with 1 mM VPA and 500 μM crocin, led to the survival and proliferation of these stem cells. Moreover, the real‑time PCR results revealed that both VPA and crocin, both individually and in combination, can significantly increase the expression levels of BDNF and GDNF in EPI‑NCSCs. According to the findings of this study, both VPA and crocin, alone and in combination, are potential candidates for enhancing the capacity of EPI‑NCSCs to differentiate into neural lineages. Therefore, the co‑treatment of EPI‑NCSCs with these drugs can be employed for the treatment of various neurological disorders, such as spinal cord injury.

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.

Entorhinal cortex stimulation induces dentate gyrus neurogenesis through insulin receptor signaling

Deep brain stimulation (DBS) has been established as a therapeutically effective method to treat pharmacological resistant neurological disorders. The molecular and cellular mechanisms underlying the beneficial effects of DBS on the brain are not yet fully understood. Beside numerous suggested mechanisms, regulation of neurogenesis is an attractive mechanism through which DBS can affect the cognitive functions. Considering the high expression of insulin receptors in hippocampus and also impaired neurogenesis in diabetic brain, the present study aimed to examine the role of insulin receptor signaling in DBS induced neurogenesis. High frequency stimulation was applied on the entorhinal cortex of rats and then neurogenesis markers in the dentate gyrus region of the hippocampus were examined using molecular and histological methods in the sham, DBS and insulin receptor antagonist-treated groups. In parallel, the changes in insulin receptor signaling in the hippocampus and spatial learning and memory performance were also assessed. DBS promoted adult hippocampal neurogenesis and facilitated the spatial memory concomitant with changes in insulin receptor signaling parameters including IR, IRS2 and GSK3β. Application of insulin receptor antagonist attenuated the DBS-induced neurogenesis. Our data emphasize that entorhinal cortex stimulation promotes adult hippocampal neurogenesis and facilitates spatial learning and memory at least partly through insulin receptors. Notably, GSK3β inhibition can play a major role in the downstream of insulin receptor signaling in DBS induced neurogenesis.

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

Growing evidence that cell-based therapies can improve recovery outcome in spinal cord injury (SCI) models substantiates their application for treatment of human with SCI. To address the effectiveness of these stem cells, potential candidates should be evaluated in proper SCI platform that allows direct real-time monitoring. In this study, the role of epidermal neural crest stem cells (EPI-NCSCs) was elucidated in an ex vivo model of SCI, and valproic acid (VPA) was administered to ameliorate the inhospitable context of injury for grafted EPI-NCSCs. Here the contusion was induced in organotypic spinal cord slice culture at day seven in vitro using a weight drop device and one hour post injury the GFP- expressing EPI-NCSCs were grafted followed by VPA administration. The evaluation of treated slices seven days after injury revealed that grafted stem cells survived on the injured slices and expressed GFAP, whereas they did not express any detectable levels of the neural progenitor marker doublecortin (DCX), which was expressed prior to transplantation. Immunoblotting data demonstrated that the expression of GFAP, BDNF, neurotrophin-3 (NT3), and Bcl2 increased significantly in stem cell treated slices. This study illustrated that the fate of transplanted stem cells has been directed to the glial lineage in the ex vivo context of injury and EPI-NCSCs may ameliorate the SCI condition through releasing neurotrophic factors directly and/or via inducing resident spinal cord cells.

Oxytocin intranasal administration as a new hope for hypogonadotropic hypogonadism patients

Hypogonadotropic hypogonadism (HH) is a form of hypogonadism which also known as secondary or central hypogonadism. Congenital HH can occur due to defect in gonadotropin releasing hormone (GnRH) neurons, upstream regulators of GnRH neurons or pituitary gonadotropic cells. Testosterone or gonadotropins therapy are widely used to treat HH patients, however both have undesirable effects and GnRH treatment for HH patients is time and cost consuming. Direct delivery of therapeutics to the brain via the nasal route is located in the center of attention during the last decade and trial application of intranasal oxytocin as a method of enhancing social interactions are reported. It has been delineated that oxytocin stimulates GnRH release from the rat hypothalamic explants and intranasal applied oxytocin up-regulates GnRH expression in the male rat hypothalamus. Therefore application of intranasal oxytocin might be a new strategy to cure HH patients.

Valproic acid preserves motoneurons following contusion in organotypic spinal cord slice culture

OBJECTIVE

Spinal cord injury (SCI) is a devastating condition causing neuronal loss. A key challenge in treatment of SCI is how to retain neurons after injury. Valproic acid (VPA) is a drug recently has been appreciated for its neuroprotective and neurotrophic properties in various SCI models. In this study the role of VPA was assessed in organotypic spinal cord slice culture following the contusion.

DESIGN

The lumbar enlargement of adult rat was cut transversely and slices were cultured. Seven days after culturing, injury was induced by dropping a 0.5 gram weight from 3 cm height on the slice surface. One hour after injury, the VPA was administered at 1, 5 and 10 µM concentrations. Afterward, at day 1 and 3 post injury (DPI: 1 and 3) propidium iodide (PI) and immunohistochemistry staining were performed to evaluate the cell death, NeuN and β-Tubulin expression, respectively.

RESULTS

The PI staining of slices at DPI: 1 and 3 following treatment with VPA revealed significant decreases in the cell death in all three concentrations comparing to the non-treated group. Also immunostaining showed VPA only at 5 µM concentration considerably rescued ventral horn' MNs from death and protected the neuronal integrity.

CONCLUSION

The results of this study indicate applying VPA one hour after injury can prevent the death of a majority of cells, importantly MNs and preserve the neuronal integrity. Since the first 24 hours after SCI is a critical period for employing any treatment, VPA can be considered as an option for further evaluation.

The Effects of Acoustic White Noise on the Rat Central Auditory System During the Fetal and Critical Neonatal Periods: A Stereological Study

AIM

To evaluate the effects of long-term, moderate level noise exposure during crucial periods of rat infants on stereological parameters of medial geniculate body (MGB) and auditory cortex.

MATERIALS AND METHODS

Twenty-four male offspring of 12 pregnant rats were divided into four groups: fetal-to-critical period group, which were exposed to noise from the last 10 days of fetal life till postnatal day (PND) 29; fetal period group that exposed to noise during the last 10 days of fetal life; critical period group, exposed to noise from PND 15 till PND 29, and control group. White noise at 90 dB for 2 h per day was used.

STATISTICAL ANALYSIS USED

Variance for variables was performed using Proc GLM followed by mean comparison by Duncan's multiple range test.

RESULTS

Numerical density of neurons in MGB of fetal-to-critical period group was lower than control group. Similar results were seen in numerical density of neurons in layers IV and VI of auditory cortex. Furthermore, no significant difference was observed in the volume of auditory cortex among groups, and only MGB volume in fetal-to-critical period group was higher than other groups. Estimated total number of neurons in MGB was not significantly different among groups.

CONCLUSION

It seems necessary to prevent long-term moderate level noise exposure during fetal-to-critical neonatal period.

Evaluation of Epidermal Neural Crest Stem Cells in Organotypic Spinal Cord Slice Culture Platform

Among various strategies employed for spinal cord injury, stem cell therapy is a potential treatment. So far, a variety of stem cells have been evaluated in animal models and humans with spinal cord injury, and epidermal neural crest stem cells represent one of the attractive types in this area. Although these multipotent stem cells have been assessed in several spinal cord injury models by independent laboratories, extensive work remains to be done to ascertain whether these cells can safely improve the outcome following human spinal cord injury. Among the models that closely mimic human spinal cord injury, the in vitro model of injury in organotypic spinal cord slice culture has been identified as one of the faithful platforms for injury-related investigations. In this study, green fluorescent protein-expressing stem cells were grafted into injured organotypic spinal cord slice culture and their survival was examined by confocal microscope seven days after transplantation. Data obtained from this preliminary study showed that these stem cells can survive on top of the surface of injured slices, as observed on day seven following their transplantation. This result revealed that this in vitro model of injury can be considered as a suitable context for further evaluation of epidermal neural crest stem cells before their application in large animals.

Organotypic Spinal Cord Culture: a Proper Platform for the Functional Screening

Recent improvements in organotypic slice culturing and its accompanying technological innovations have made this biological preparation increasingly useful ex vivo experimental model. Among organotypic slice cultures obtained from various central nervous regions, spinal cord slice culture is an absorbing model that represents several unique advantages over other current in vitro and in vivo models. The culture of developing spinal cord slices, as allows real-time observation of embryonic cells behaviors, is an instrumental platform for developmental investigation. Importantly, due to the ability of ex vivo models to recapitulate different aspects of corresponding in vivo conditions, these models have been subject of various manipulations to derive disease-relevant slice models. Moreover spinal cord slice cultures represent a potential platform for screening of different pharmacological agents and evaluation of cell transplantation and neuroregenerative materials. In this review, we will focus on studies carried out using the ex vivo model of spinal cord slice cultures and main advantages linked to practicality of these slices in both normal and neuropathological diseases and summarize them in different categories based on application.