Functional recovery and neuronal regeneration of a rat model of epilepsy by transplantation of Hes1-down regulated bone marrow stromal cells

Therapeutic Potential of Mesenchymal Stem Cells in the Treatment of Epilepsy and Their Interaction with Antiseizure Medications

Epilepsy is a life-threatening neurological disease that affects approximately 70 million people worldwide. Although the vast majority of patients may be successfully managed with currently used antiseizure medication (ASM), the search for alternative therapies is still necessary due to pharmacoresistance in about 30% of patients with epilepsy. Here, we review the effects of ASMs on stem cell treatment when they could be, as expected, co-administered. Indeed, it has been reported that ASMs produce significant effects on the differentiation and determination of stem cell fate. In addition, we discuss more recent findings on mesenchymal stem cells (MSCs) in pre-clinical and clinical investigations. In this regard, their ability to differentiate into various cell types, reach damaged tissues and produce and release biologically active molecules with immunomodulatory/anti-inflammatory and regenerative properties make them a high-potential therapeutic tool to address neuroinflammation in different neurological disorders, including epilepsy. Overall, the characteristics of MSCs to be genetically engineered, in order to replace dysfunctional elements with the aim of restoring normal tissue functioning, suggested that these cells could be good candidates for the treatment of epilepsy refractory to ASMs. Further research is required to understand the potential of stem cell treatment in epileptic patients and its interaction with ASMs.

Tail-vein injection of MSC-derived small extracellular vesicles facilitates the restoration of hippocampal neuronal morphology and function in APP / PS1 mice

Mesenchymal stem-cell-derived small extracellular vesicles (MSC-EVs), as a therapeutic agent, have shown great promise in the treatment of neurological diseases. To date, the neurorestorative effects and underlying mechanism of MSC-EVs in Alzheimer's disease (AD) are not well known. Herein, we aimed to investigate the action of MSC-EVs on the neuronal deficits in β-amyloid protein (Aβ)-stimulated hippocampal neurons, or AD cell (SHSY5Y cell lines) and animal (APPswe / PS1dE9 mice) models. In the present study, the cell and AD models received a single-dose of MSC-EVs, and were then assessed for behavioral deficits, pathological changes, intracellular calcium transients, neuronal morphology alterations, or electrophysiological variations. Additionally, the nuclear factor E2-related factor 2 (Nrf2, a key mediator of neuronal injury in AD) signaling pathway was probed by western blotting in vitro and in vivo models of AD. Our results showed that MSC-EVs therapy improved the cognitive impairments and reduced the hippocampal Aβ aggregation and neuronal loss in AD mice. Markedly, EV treatment restored the calcium oscillations, dendritic spine alterations, action potential abnormalities, or mitochondrial changes in the hippocampus of AD models. Also, we found that the Nrf2 signaling pathway participated in the actions of MSC-EVs in the cell and animal models. Together, these data indicate that MS-EVs as promising nanotherapeutics for restoration of hippocampal neuronal morphology and function in APP / PS1 mice, further highlighting the clinical values of MSC-EVs in the treatment of AD.

High mobility group box-1 (HMGB1) antagonist BoxA suppresses status epilepticus-induced neuroinflammatory responses associated with Toll-like receptor 2/4 down-regulation in rats

It has been generally accepted that inflammatory responses induced by status epilepticus (SE) in the brain are associated with microglial activation. One important regulator of microglial activation is high mobility group box-1 (HMGB1) protein. HMGB1 exerts its influence on microglia via various pathways including Toll-like receptor (TLR) subtypes 2 and 4. To explore the HMGB1 role in the SE-induced microglial activation and the involvement of TLRs we conducted in vivo and ex vivo experiments using the HMGB1 antagonist BoxA. Blood-brain barrier (BBB) permeability, brain water content, hippocampal neuroinflammation and neuronal apoptosis were measured 24 h after the pilocarpine induction of status epilepticus (SE) in Sprague-Dawley rats treated with BoxA. In ex vivo experiments, post-SE microglia cells were isolated from the hippocampal CA1 area and subjected to lipopolysaccharide (LPS) stimulation followed by inflammatory cytokine IL-1β and IL-6 by qPCR and HMGB1, TLR2, TLR3 by Western blotting. A significant down-regulation of IL-1β, IL-6 and TNF-α but not HMGB1 was found in BoxA-treated compared to untreated animals. These changes were associated with decreased BBB permeability, reduced hippocampal neuronal apoptosis and reduction in hippocampal microglial activation. We conclude that BoxA-induced suppression of HMGB1-mediated neuroinflammatory responses is associated with TLR-2 and 4 down-regulation and should be explored as a potential therapeutic target.

Glycyrrhizin, an HMGB1 inhibitor, exhibits neuroprotective effects in rats after lithium-pilocarpine-induced status epilepticus

Objectives

It has been proven that extracellular HMGB1 is involved in progression of neurologic disorders, such as stroke, traumatic brain injury, meningitis and epilepsy. Glycyrrhizin (GL) is a direct inhibitor of HMGB1, and blocks HMGB1 release into the extracellular. We aim in this study to investigate the neuroprotective effects of GL in a rat model after lithium-pilocarpine-induced status epilepticus (SE).

Methods

Adult male SD rats were divided into three groups: Sham group, SE-group and (SE + GL)-treated group. The HMGB1 expression in serum and hippocampus, the damage extent of blood brain barrier (BBB) and hippocampal neuronal damage were evaluated by enzyme-linked immunosorbent assay, immunohistochemistry, western blot and nissl's staining.

Key findings

Glycyrrhizin markedly reduced HMGB1 expression in serum and hippocampus, prevented HMGB1 translocation from nucleus to cytoplasm in hippocampal CA1, CA3 and hilus areas of SE rats. Meanwhile, GL significantly ameliorated neuronal damage in the CA1, CA3 and hilus areas of hippocampus, and protected BBB disruption after SE. The administration of GL significantly decreased the mortality from 25 to 8.9% in rats.

Conclusions

Glycyrrhizin may exert neuroprotective effects via inhibiting HMGB1 and protect BBB permeability in lithium-pilocarpine-induced rats with SE.

MRI tracking of bone marrow mesenchymal stem cells labeled with ultra-small superparamagnetic iron oxide nanoparticles in a rat model of temporal lobe epilepsy

Transplantation of bone marrow mesenchymal stem cells (BMSCs) is a promising approach for treatment of epilepsy. To our knowledge, there is little research on magnetic resonance imaging (MRI) tracking of BMSCs labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles in a rat model of temporal lobe epilepsy (TLE). In this study, BMSCs were pre-labeled with USPIO nanoparticles, and then the cell apoptosis, proliferation, surface antigens, and multipotency were investigated. Lithium chloride-pilocarpine induced TLE models were administered by USPIO-labeled BMSCs (U-BMSCs), BMSCs, and saline through lateral ventricle injection as the experimental group, control I group and control II group, respectively, followed by MRI examination, electroencephalography (EEG) and Prussian blue staining. The cell experimental results showed that the labeled USPIO did not affect the biological characteristics and multiple potential of BMSCs. The U-BMSCs can be detected using MRI in vitro and in vivo, and observed in the hippocampus and adjacent parahippocampal cortical areas of the epileptic model. Moreover, electroencephalographic results showed that transplanted U-BMSCs, as well as BMSCs, were capable of reducing the number of epileptiform waves significantly (P<0.01) compared with control II group. All of these findings suggest that it is feasible to track transplanted BMSCs using MRI in a rat model of TLE, and support that USPIO labeling is a valuable tool for cell tracking in the study of seizure disorders.

Over-expression of Mash1 improves the GABAergic differentiation of bone marrow mesenchymal stem cells in vitro

Bone marrow mesenchymal stem cells (BMSCs) have been shown to be a promising cell type for the study of neuronal differentiation; however, few attempts had been made to differentiate these cells into inhibitory gamma-aminobutyric acid (GABA)ergic neurons. In this study, we over-expressed mammalian achaete-scute homologue-1 (Mash1), a basic helix-loop-helix (bHLH) transcription factor, in Sprague-Dawley rat BMSCs via lentiviral vectors, and then induced neuronal differentiation of these cells using conditioned medium. Our Western blot results show that, under conditions of differentiation, Mash1-overexpressing BMSCs exhibit an increased expression of neuronal markers and a greater degree of neuronal morphology compared to control, non-Mash1-overexpressing cells. Using immunocytochemistry, we observed increased expression of glutamic acid decarboxylase 67 (GAD67), as well as neuron-specific nuclear protein (NeuN) and β3-tubulin, in Mash1-overexpressing BMSCs compared to control cells. Moreover, we also found the differentiated cells showed representative traces of action potentials in electrophysiological characterization. In conclusion, our study demonstrated that over-expression of Mash1 can improve GABAergic differentiation of BMSCs in vitro.

Improvement of contusive spinal cord injury in rats by co-transplantation of gamma-aminobutyric acid-ergic cells and bone marrow stromal cells

BACKGROUND AIMS

Cell therapy is considered a promising option for treatment of spinal cord injury (SCI). The purpose of this study is to use combined therapy of bone marrow stromal cells (BMSCs) and BMSC-derived gamma-aminobutyric acid (GABA)ergic inhibitory neurotransmitter cells (BDGCs) for the contusion model of SCI in rats.

METHODS

BDGCs were prepared from BMSCs by pre-inducing them with β-mercaptoethanol followed by retinoic acid and then inducing them by creatine. They were immunostained with BMSC, proneuronal, neural and GABA markers. The BDGCs were intraspinally transplanted into the contused rats, whereas the BMSCs were delivered intravenously. The animals were sacrificed after 12 weeks.

RESULTS

The Basso, Beattie and Bresnahan test showed improvement in the animals with the combined therapy compared with the untreated animals, the animals treated with GABAergic cells only and the animals that received BMSCs. The immunohistochemistry analysis of the tissue sections prepared from the animals receiving the combined therapy showed that the transplanted cells were engrafted and integrated into the injured spinal cord; in addition, a significant reduction was seen in the cavitation.

CONCLUSIONS

The study shows that the combination of GABAergic cells with BMSCs can improve SCI.