Induction of human mesenchymal stem cells into dopamine-producing cells with different differentiation protocols

Characterization of three washing/decellularization procedures for the production of bioactive human micronized neural tissue (hMINT)

BACKGROUND

We developed a novel, injectable and decellularized human peripheral nerve-based scaffold, named Micronized Human Neural Tissue (hMINT), designed to be used as a supportive matrix for stem cell transplantation in the context of spinal cord injury (SCI).

MATERIALS AND METHODS

Human donated sciatic nerves were micronized at liquid nitrogen temperature prior to decellularization using 3 different procedures of various harshness. hMINT were characterized in terms of particle size, DNA, sulfated glycosaminoglycans (sGAG) and growth factors content. To test the biocompatibility and bioactivity of the various preparations, we used a type of mesenchymal stromal cells (MSCs), termed MIAMI cells, which were placed in contact with hMINT to monitor cell attachment by confocal microscopy and gene expression by RT-qPCR in vitro.

RESULTS

The content of DNA, sGAG and growth factors left in the product after processing was highly dependent on the decellularization procedure used. We demonstrated that hMINT are biocompatible and promoted the attachment and long-term survival of MIAMI cells in vitro. Finally, combination with hMINT increased MIAMI cells mRNA expression of pro-survival and anti-inflammatory factors. Importantly, the strongest bioactivity on MIAMI cells was observed with the hMINT decellularized using the mildest decellularization procedure, therefore emphasizing the importance of achieving an adequate decellularization without losing the hMINT's bioactivity.

PERSPECTIVES AND CLINICAL SIGNIFICANCE

The capacity of hMINT/stem cells to facilitate protection of injured neural tissue, promote axon re-growth and improve functional recovery will be tested in an animal model of SCI and other neurodegenerative disorders in the future.

Bone Tissue and the Nervous System: What Do They Have in Common?

Degenerative diseases affecting bone tissues and the brain represent important problems with high socio-economic impact. Certain bone diseases, such as osteoporosis, are considered risk factors for the progression of neurological disorders. Often, patients with neurodegenerative diseases have bone fractures or reduced mobility linked to osteoarthritis. The bone is a dynamic tissue involved not only in movement but also in the maintenance of mineral metabolism. Bone is also associated with the generation of both hematopoietic stem cells (HSCs), and thus the generation of the immune system, and mesenchymal stem cells (MSCs). Bone marrow is a lymphoid organ and contains MSCs and HSCs, both of which are involved in brain health via the production of cytokines with endocrine functions. Hence, it seems clear that bone is involved in the regulation of the neuronal system and vice versa. This review summarizes the recent knowledge on the interactions between the nervous system and bone and highlights the importance of the interaction between nerve and bone cells. In addition, experimental models that study the interaction between nerve and skeletal cells are discussed, and innovative models are suggested to better evaluate the molecular interactions between these two cell types.

Stem Cell-based and Advanced Therapeutic Modalities for Parkinson's Disease: A Risk-effectiveness Patient-centered Analysis

Treatment of Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, is currently considered a challenging issue since it causes substantial disability, poor quality of life, and mortality. Despite remarkable progress in advanced conventional therapeutic interventions, the global burden of the disease has nearly doubled, prompting us to assess the riskeffectiveness of different treatment modalities. Each protocol could be considered as the best alternative treatment depending on the patient's situation. Prescription of levodopa, the most effective available medicine for this disorder, has been associated with many complications, i.e., multiple episodes of "off-time" and treatment resistance. Other medications, which are typically used in combination with levodopa, may have several adverse effects as well. As a result, the therapies that are more in line with human physiology and make the least interference with other pathways are worth investigating. On the other hand, remaining and persistent symptoms after therapy and the lack of effective response to the conventional approaches have raised expectations towards innovative alternative approaches, such as stem cell-based therapy. It is critical to not overlook the unexplored side effects of innovative approaches due to the limited number of research. In this review, we aimed to compare the efficacy and risk of advanced therapies with innovative cell-based and stemcell- based modalities in PD patients. This paper recapitulated the underlying factors/conditions, which could lead us to more practical and established therapeutic outcomes with more advantages and few complications. It could be an initial step to reconsider the therapeutic blueprint for patients with Parkinson's disease.

The potential use of mesenchymal stem cells and their exosomes in Parkinson's disease treatment

Parkinson's disease (PD) is the second most predominant neurodegenerative disease worldwide. It is recognized clinically by severe complications in motor function caused by progressive degeneration of dopaminergic neurons (DAn) and dopamine depletion. As the current standard of treatment is focused on alleviating symptoms through Levodopa, developing neuroprotective techniques is critical for adopting a more pathology-oriented therapeutic approach. Regenerative cell therapy has provided us with an unrivalled platform for evaluating potentially effective novel methods for treating neurodegenerative illnesses over the last two decades. Mesenchymal stem cells (MSCs) are most promising, as they can differentiate into dopaminergic neurons and produce neurotrophic substances. The precise process by which stem cells repair neuronal injury is unknown, and MSC-derived exosomes are suggested to be responsible for a significant portion of such effects. The present review discusses the application of mesenchymal stem cells and MSC-derived exosomes in PD treatment.

Serum-Free Cultures: Could They Be a Future Direction to Improve Neuronal Differentiation of Mesenchymal Stromal Cells?

Mesenchymal stem/stromal cells (MSCs) are undifferentiated cells with multilinear potential, known for their immunomodulatory and regenerative properties. Although the scientific community is working to improve their application, concerns limit their use to repair tissues following neurological damage. One of these obstacles is represented by the use of culture media supplemented with fetal bovine serum (FBS), which, due to its xenogenic nature and the risk of contamination, has increased scientific, ethical and safety problems. Therefore, the use of serum-free media could improve MSC culture methods, avoiding infectious and immunogenic transmission problems as well as MSC bioprocesses, without the use of animal components. The purpose of our review is to provide an overview of experimental studies that demonstrate that serum-free cultures, along with the supplementation of growth factors or chemicals, can lead to a more defined and controlled environment, enhancing the proliferation and neuronal differentiation of MSCs.

The Regenerative Potential of bFGF in Dental Pulp Repair and Regeneration

Regenerative endodontic therapy intends to induce the host’s natural wound-healing process, which can restore the vitality, immunity, and sensitivity of the inflammatory or necrotic pulp tissue destroyed by infection or trauma. Myriads of growth factors are critical in the processes of pulp repair and regeneration. Among the key regulatory factors are the fibroblast growth factors, which have turned out to be the master regulators of both organogenesis and tissue homeostasis. Fibroblast growth factors, a family composed of 22 polypeptides, have been used in tissue repair and regeneration settings, in conditions as diverse as burns, ulcers, bone-related diseases, and spinal cord injuries. Meanwhile, in dentistry, the basic fibroblast growth factor is the most frequently investigated. Thereby, the aim of this review is 2-fold: 1) foremost, to explore the underlying mechanisms of the bFGF in dental pulp repair and regeneration and 2) in addition, to shed light on the potential therapeutic strategies of the bFGF in dental pulp–related clinical applications.

Mesenchymal stem cells in Parkinson's disease: Motor and nonmotor symptoms in the early posttransplant period

Background

Treatment of patients with Parkinson disease (PD) using autologous mesenchymal stem cells (MSCs) is a promising method to influence the pathogenesis of the disease. The aim of this study was to assess the immediate results of the introduction of MSCs on the effectiveness of motor and nonmotor symptoms in patients with PD.

Methods

MSCs were transplanted to 12 patients with PD through intravenous and tandem (intranasal + intravenous) injections. Effectiveness of the therapy was evaluated 1 and 3 months posttransplantation. Neurological examination of the intensity of motor symptoms was carried out in the morning after a 12 or 24 h break in taking antiparkinsonian drugs, then 1 h after they were taken. The intensity of motor symptoms was assessed with the help of Section III of the Unified PD Rating Scale of the International Society for Movement Disorders (UPDRS). The intensity of nonmotor symptoms was assessed with the help of the following scales: Hamilton Depression Rating Scale, the Pittsburgh Sleep Quality Index, the Epworth Sleepiness Scale, Nonmotor Symptoms Scale, and the 39-item Parkinson's Disease Questionnaire.

Results

We found a statistically significant decrease in the severity of motor and nonmotor symptoms in the study group in the posttransplant period.

Conclusion

Positive results allow us to consider MSCs transplantation as a disease-modifying therapeutic strategy in PD. However, this method of PD treatment is not a fully understood process, which requires additional studies and a longer follow-up period to monitor the patients' condition posttransplantation.

Effect of Bone Marrow Stromal Cells in Parkinson's Disease Rodent Model: A Meta-Analysis

Background: Bone marrow stromal cells (BMSCs) has been reported to have beneficial effects in improving behavioral deficits, and rescuing dopaminergic neuron loss in rodent models of Parkinson's disease (PD). However, their pooled effects for dopaminergic neuron have yet to be described.

Objective: To review the neuroprotective effect of naïve BMSCs in rodent models of PD.

Methods: The PubMed, EMBASE, and Web of Science databases were searched up to September 30, 2020. Inclusion criteria according to PICOS criteria were as follows: (1) population: rodents; (2) intervention: unmodified BMSCs; (3) comparison: not specified; (4) primary outcome: tyrosine hydroxylase level in the substantia nigra pars compacta and rotational behavior; secondary outcome: rotarod test, and limb function; (5) study: experimental studies. Multiple prespecified subgroup and meta-regression analysis were conducted. Following quality assessment, random effects models were used for this meta-analysis.

Results: Twenty-seven animal studies were included. The median quality score was 4.7 (interquartile range, 2–8). Overall standardized mean difference between animals treated with naïve BMSCs and controls was 2.79 (95% confidence interval: 1.70, 3.87; P < 0.001) for densitometry of tyrosine hydroxylase-positive staining; −1.54 (95% confidence interval: −2.11, −0.98; P < 0.001) for rotational behavior. Significant heterogeneity among studies was observed.

Conclusions: Results of this meta-analysis suggest that naïve BMSCs therapy increased dopaminergic neurons and ameliorated behavioral deficits in rodent models of PD.

Basic fibroblast growth factor promotes human dental pulp stem cells cultured in 3D porous chitosan scaffolds to neural differentiation

AIM/PURPOSE

Dental pulp stem cells (DPSCs) were widely used as seed cells in the field of tissue engineering and regenerative medicine, including spinal cord injury (SCI) repair and other neuronal degenerative diseases, due to their easy isolation, multiple differentiation potential, low immunogenicity and low rates of rejection during transplantation. Various studies have shown that bFGF can enhance peripheral nerve regeneration after injury, and phospho-ERK (p-ERK) activation as a major mediator may be involved in this process. Previous studies also have proved that a suitable biomaterial scaffold can carry and transport the therapeutic cells effectively to the recipient area. It has showed in our earlier experiments that 3D porous chitosan scaffolds exhibited a suitable circumstance for survival and neural differentiation of DPSCs in vitro. The purpose of the study was to evaluate the influence of chitosan scaffolds and bFGF on differentiation of DPSCs.

MATERIALS AND METHODS

In current study, DPSCs were cultured in chitosan scaffolds and treated with neural differentiation medium for 7 days. The neural genes and protein markers were analyzed by western blot and immunofluorescence. Meanwhile, the relevant signaling pathway involved in this process was also tested.

RESULTS

Our study revealed that the viability of DPSCs was not influenced by co-culture with the chitosan scaffolds as well as bFGF. Compared with the control and DPSC/chitosan-scaffold groups, the levels of GFAP, S100β and β-tubulin III significantly increased in the DPSC/chitosan-scaffold+bFGF group.

CONCLUSION

Chitosan scaffolds were non-cytotoxic to the survival of DPSCs, and chitosan scaffolds combined with bFGF facilitated the neural differentiation of DPSCs. The transplantation of DPSCs/chitosan-scaffold+bFGF might be a secure and effective method of treating SCI and other neuronal diseases.

Forskolin and IBMX Induce Neural Transdifferentiation of MSCs Through Downregulation of the NRSF

Neural differentiation of mesenchymal stem cells is a controversial phenomenon, as it would require transdifferentiation across the mesoderm-ectoderm barrier. However, several laboratories have observed that MSCs are able to be induced to express neural characteristics. Previously, we demonstrated that the cAMP-elevating agents, forskolin and IBMX, induced neural-like differentiation of MSCs, including expression of neural markers and increased sensitivity to neurotransmitters. However, due to the broad range of effects that forskolin and IBMX can elicit through the intracellular second messenger, cAMP, a better mechanistic understanding is required. Here, we show that neural induction by forskolin and IBMX is dependent on downregulation of expression of the master transcriptional regulator, neuron restrictive silencer factor (NRSF), and its downstream target genes. Since silencing of NRSF is known to initiate neural differentiation, it suggests that forskolin and IBMX result in transdifferentiation of MSCs into a neural lineage.

MPP+ decreases store-operated calcium entry and TRPC1 expression in Mesenchymal Stem Cell derived dopaminergic neurons

Parkinson's disease is a neurodegenerative disorder involving the progressive loss of dopaminergic neurons (DNs), with currently available therapeutics, such as L-Dopa, only able to relieve some symptoms. Stem cell replacement is an attractive therapeutic option for PD patients, and DNs derived by differentiating patient specific stem cells under defined in-vitro conditions may present a viable opportunity to replace dying neurons. We adopted a previously published approach to differentiate Mesenchymal Stem Cells (MSCs) into DN using a 12-day protocol involving FGF-2, bFGF, SHH ligand and BDNF. While MSC-derived DNs have been characterized for neuronal markers and electrophysiological properties, we investigated store-operated calcium entry (SOCE) mechanisms of these DNs under normal conditions, and upon exposure to environmental neurotoxin, 1-methyl, 4-phenyl pyridinium ion (MPP+). Overall, we show that MSC-derived DNs are functional with regard to SOCE mechanisms, and MPP+ exposure dysregulates calcium signaling, making them vulnerable to neurodegeneration. Since in-vitro differentiation of MSCs into DNs is an important vehicle for PD disease modeling and regenerative medicine, the results of this study may help with understanding of the pathological mechanisms underlying PD.

Pluripotent stem cell-based therapy for Parkinson's disease: Current status and future prospects

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, which affects about 0.3% of the general population. As the population in the developed world ages, this creates an escalating burden on society both in economic terms and in quality of life for these patients and for the families that support them. Although currently available pharmacological or surgical treatments may significantly improve the quality of life of many patients with PD, these are symptomatic treatments that do not slow or stop the progressive course of the disease. Because motor impairments in PD largely result from loss of midbrain dopamine neurons in the substantia nigra pars compacta, PD has long been considered to be one of the most promising target diseases for cell-based therapy. Indeed, numerous clinical and preclinical studies using fetal cell transplantation have provided proof of concept that cell replacement therapy may be a viable therapeutic approach for PD. However, the use of human fetal cells as a standardized therapeutic regimen has been fraught with fundamental ethical, practical, and clinical issues, prompting scientists to explore alternative cell sources. Based on groundbreaking establishments of human embryonic stem cells and induced pluripotent stem cells, these human pluripotent stem cells have been the subject of extensive research, leading to tremendous advancement in our understanding of these novel classes of stem cells and promising great potential for regenerative medicine. In this review, we discuss the prospects and challenges of human pluripotent stem cell-based cell therapy for PD.

Effects of Passage Number and Differentiation Protocol on the Generation of Dopaminergic Neurons from Rat Bone Marrow-Derived Mesenchymal Stem Cells

Multiple studies have demonstrated the ability of mesenchymal stem cells (MSCs) to differentiate into dopamine-producing cells, in vitro and in vivo, indicating their potential to be used in the treatment of Parkinson’s disease (PD). However, there are discrepancies among studies regarding the optimal time (i.e., passage number) and method for dopaminergic induction, in vitro. In the current study, we compared the ability of early (P4) and later (P40) passaged bone marrow-derived MSCs to differentiate into dopaminergic neurons using two growth-factor-based approaches. A direct dopaminergic induction (DDI) was used to directly convert MSCs into dopaminergic neurons, and an indirect dopaminergic induction (IDI) was used to direct MSCs toward a neuronal lineage prior to terminal dopaminergic differentiation. Results indicate that both early and later passaged MSCs exhibited positive expression of neuronal and dopaminergic markers following either the DDI or IDI protocols. Additionally, both early and later passaged MSCs released dopamine and exhibited spontaneous neuronal activity following either the DDI or IDI. Still, P4 MSCs exhibited significantly higher spiking and bursting frequencies as compared to P40 MSCs. Findings from this study provide evidence that early passaged MSCs, which have undergone the DDI, are more efficient at generating dopaminergic-like cells in vitro, as compared to later passaged MSCs or MSCs that have undergone the IDI.

Dextran-coated iron oxide nanoparticle-improved therapeutic effects of human mesenchymal stem cells in a mouse model of Parkinson's disease

Parkinson's disease (PD) is a prevalent neurodegenerative disease characterized by the loss of dopaminergic (DA) neurons. With their migration capacity toward the sites of diseased DA neurons in the PD brain, mesenchymal stem cells (MSCs) have the potential to differentiate to DA neurons for the replacement of damaged neurons and to secrete neurotrophic factors for the protection and regeneration of diseased DA neurons; therefore MSCs show promise for the treatment of PD. In this study, for the first time, we demonstrate that dextran-coated iron oxide nanoparticles (Dex-IO NPs) can improve the therapeutic efficacy of human MSCs (hMSCs) in a mouse model of PD induced by a local injection of 6-hydroxydopamine (6-OHDA). In situ examinations not only show that Dex-IO NPs can improve the rescue effect of hMSCs on the loss of host DA neurons but also demonstrate that Dex-IO NPs can promote the migration capacity of hMSCs toward lesioned DA neurons and induce the differentiation of hMSCs to DA-like neurons at the diseased sites. We prove that in vitro Dex-IO NPs can enhance the migration of hMSCs toward 6-OHDA-damaged SH-SY5Y-derived DA-like cells, induce hMSCs to differentiate to DA-like neurons in the conditioned media derived from 6-OHDA-damaged SH-SY5Y-derived DA-like cells and promote the protection/regeneration effects of hMSCs on 6-OHDA-damaged SH-SY5Y-derived DA-like cells. We confirm the potential of MSCs for cell-based therapy for PD. Dex-IO NPs can be used as a tool to accelerate and optimize MSC therapeutics for PD applicable clinically.

Synergistic Effect of BDNF and FGF2 in Efficient Generation of Functional Dopaminergic Neurons from human Mesenchymal Stem Cells

To understand the process of neurogenesis, generation of functional dopaminergic (DAergic) neurons from human mesenchymal stem cells (hMSCs) is important. BDNF has been reported to be responsible for inducing neuronal maturation and functionality. Previously, we have reported the efficient generation of neurons from human bone marrow derived MSCs using FGF2 alone. We hypothesize that hMSCs from various tissues [(bone marrow (BM), adipose tissue (AD) and dental pulp (DP)], if treated with BDNF on 9th day of induction, alongwith FGF2 will generate functional DAergic neurons. Hence, cells were characterized at morphometric, transcription and translational levels for various markers like MAP2, TH, NGN2, PITX3, DAT, synaptophysin, Kv4.2 and SCN5A. Functionality of in vitro generated neurons was studied by calcium ion imaging. Result analysis depicted that BDNF has effect on expression of dopaminergic neuronal markers at gene and protein levels and functionality of neurons. Among these hMSCs, DP-MSC showed significantly better neuronal characteristics in terms of morphology, expression of neuronal markers and foremost, functionality of neurons. From the present study, therefore, we concluded that i) BDNF has additive effect on neuronal characteristics and functionality ii) DP-MSC are better MSC candidate to study DAergic neurogenesis and perform future studies.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials.

Concise Review: Mesenchymal Stem Cells in Neurodegenerative Diseases

Stem cell-based therapies for neurodegenerative diseases aim at halting clinical deterioration by regeneration and by providing local support for damaged tissue. Mesenchymal stem cells (MSCs) hold great potential for cell therapy as they can be efficiently derived from adult tissue, ex vivo expanded in culture and safely transplanted autologously. MSCs were also shown to be able to differentiate toward neural fates and to secrete a broad range of factors able to promote nervous tissue maintenance and repair. Moreover, upon transplantation, MSCs were shown capable of homing toward lesioned areas, implying their potential use as vehicles for therapeutic agents administration. Indeed, various advantageous effects were reported following human MSCs transplantation into rodent models of neurodegenerative diseases, such as neurotrophic factor-mediated protection, enhanced neurogenesis, modulation of inflammation, and abnormal protein aggregate clearance. Per journal style, most nonstandard abbreviations must be used at least two times in the abstract to be retained; NTF was used once and thus has been deleted. Recent studies have also used ex vivo manipulation for enhanced expression of potentially favorable factors, by so exploiting the homing capacity of MSCs for effective expression at the lesion site. Here, we will summarize current advancements in MSCs-based therapies for neurodegenerative diseases. We will examine the roles of central mechanisms suggested to mediate the beneficial effects of MSCs-based therapy and consider the augmentation of these mechanisms for superior clinical outcomes in rodent models of neurodegeneration as well as in clinical trials. Stem Cells 2017;35:1867-1880.

PKA-GSK3β and β-Catenin Signaling Play a Critical Role in Trans-Resveratrol Mediated Neuronal Differentiation in Human Cord Blood Stem Cells

The role of resveratrol (RV), a natural polyphenol, is well documented, although its role on neurogenesis is still controversial and poorly understood. Therefore, to decipher the cellular insights of RV on neurogenesis, we investigated the potential effects of the compound on the survival, proliferation, and neuronal differentiation of human cord blood-derived mesenchymal stem cells (hCBMSCs). For neuronal differentiation, purified and characterized hCBMSCs were exposed to biological safe doses of RV (10 μM) alone and in combination with nerve growth factor (NGF-50 ng). The cells exposed only to NGF (50 ng/mL) served as positive control for neuronal differentiation. The genes showing significant involvement in the process of neuronal differentiation were further funneled down at transcriptional and translational level. It was observed that RV promotes PKA-mediated neuronal differentiation in hCBMSCs by inducing canonical pathway. The studies with pharmacological inhibitors also confirmed that PKA significantly induces β-catenin expression via GSK3β induction and stimulates CREB phosphorylation and pERK1/2 induction. Besides that, the studies also revealed that RV additionally possesses the binding sites for molecules other than PKA and GSK3β, with which it interacts. The present study therefore highlights the positive impact of RV over the survival, proliferation, and neuronal differentiation in hCBMSCs via PKA-mediated induction of GSK3β, β catenin, CREB, and ERK1/2.

Isolation and Characterization of Human Chorionic Membranes Mesenchymal Stem Cells and Their Neural Differentiation

Mesenchymal stem cells (MSCs) can be obtained from a variety of human tissues. Placenta has become an attractive stem cell source for potential applications in regenerative medicine and tissue engineering. The aim of this study was to localize and characterize MSCs within human chorionic membranes (hCMSCs). For this purpose, immunofluorescence labeling with CD105 and CD90 were used to determine the distribution of MSCs in chorionic membranes tissue. A medium supplemented with a synthetic serum and various concentrations of neurotrophic factors and cytokines was used to induce hCMSCs to neural cells. The results showed that the CD90 positive cells were scattered in the chorionic membranes tissue, and the CD105 positive cells were mostly located around the small blood vessels. hCMSCs expressed typical mesenchymal markers (CD73, CD90, CD105, CD44 and CD166) but not hematopoietic markers (CD45, CD34) and HLA-DR. hCMSCs differentiated into adipocytes, osteocytes, chondrocytes, and neuronal cells, as revealed by morphological changes, cell staining, immunofluorescence analyses, and RT-PCR showing the tissue-specific gene presence for differentiated cell lineages after the treatment with induce medium. Human chorionic membranes may be the source of MSCs for treatment of nervous system injury.

Mesenchymal stem cell therapy in Parkinson's disease animal models

Parkinson's disease is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra, and as a consequence, by decreased dopamine levels in the striatum. Currently available therapies are not able to stop or reverse the progression of the disease. A novel therapeutic approach is based on cell therapy with stem cells, in order to replace degenerated neurons. Among stem cells, mesenchymal stem cells seemed the most promising thanks to their capacities to differentiate toward dopaminergic neurons and to release neurotrophic factors. Indeed, mesenchymal stem cells are able to produce different molecules with immunomodulatory, neuroprotective, angiogenic, chemotactic effects and that stimulate differentiation of resident stem cells. Mesenchymal stem cells were isolated for the first time from bone marrow, but can be collected also from adipose tissue, umbilical cord and other tissues. In this review, we focused our attention on mesenchymal stem cells derived from different sources and their application in Parkinson's disease animal models.

Transplantation of Human Skin-Derived Mesenchymal Stromal Cells Improves Locomotor Recovery After Spinal Cord Injury in Rats

Spinal cord injury (SCI) is a devastating neurologic disorder with significant impacts on quality of life, life expectancy, and economic burden. Although there are no fully restorative treatments yet available, several animal and small-scale clinical studies have highlighted the therapeutic potential of cellular interventions for SCI. Mesenchymal stem cells (MSCs)-which are conventionally isolated from the bone marrow-recently emerged as promising candidates for treating SCI and have been shown to provide trophic support, ameliorate inflammatory responses, and reduce cell death following the mechanical trauma. Here we evaluated the human skin as an alternative source of adult MSCs suitable for autologous cell transplantation strategies for SCI. We showed that human skin-derived MSCs (hSD-MSCs) express a range of neural markers under standard culture conditions and are able to survive and respond to neurogenic stimulation in vitro. In addition, using histological analysis and behavioral assessment, we demonstrated as a proof-of-principle that hSD-MSC transplantation reduces the severity of tissue loss and facilitates locomotor recovery in a rat model of SCI. Altogether, the study provides further characterization of skin-derived MSC cultures and indicates that the human skin may represent an attractive source for cell-based therapies for SCI and other neurological disorders. Further investigation is needed to elucidate the mechanisms by which hSD-MSCs elicit tissue repair and/or locomotor recovery.

Cell Signaling and Differential Protein Expression in Neuronal Differentiation of Bone Marrow Mesenchymal Stem Cells with Hypermethylated Salvador/Warts/Hippo (SWH) Pathway Genes

Human mesenchymal stem cells (MSCs) modified by targeting DNA hypermethylation of genes in the Salvador/Warts/Hippo pathway were induced to differentiate into neuronal cells in vitro. The differentiated cells secreted a significant level of brain-derived neurotrophy factor (BDNF) and the expression of BDNF receptor tyrosine receptor kinase B (TrkB) correlated well with the secretion of BDNF. In the differentiating cells, CREB was active after the binding of growth factors to induce phosphorylation of ERK in the MAPK/ERK pathway. Downstream of phosphorylated CREB led to the functional maturation of differentiated cells and secretion of BDNF, which contributed to the sustained expression of pERK and pCREB. In summary, both PI3K/Akt and MAPK/ERK signaling pathways play important roles in the neuronal differentiation of MSCs. The main function of the PI3K/Akt pathway is to maintain cell survival during neural differentiation; whereas the role of the MAPK/ERK pathway is probably to promote the maturation of differentiated MSCs. Further, cellular levels of protein kinase C epsilon type (PKC-ε) and kinesin heavy chain (KIF5B) increased with time of induction, whereas the level of NME/NM23 nucleoside diphosphate kinase 1 (Nm23-H1) decreased during the time course of differentiation. The correlation between PKC-ε and TrkB suggested that there is cross-talk between PKC-ε and the PI3K/Akt signaling pathway.

A lower volume culture method for obtaining a larger yield of neuron-like cells from mesenchymal stem cells

Mesenchymal stem cells (MSCs) represent a promising cell source for stem cell therapy to replace neurons damaged by neurodegenerative diseases. A system designed for in vitro neuronal differentiation of MSCs is an indispensable technique, which provides MSC-derived functional neurons for cell-replacement therapies and valuable information in pre-clinical research. This study investigated the effects of reducing the volume of neural induction medium on cell viability and neural differentiation of MSCs. When MSCs were differentiated in low volumes of neural induction medium, rather than using the conventional method, the cell density on culture dishes significantly increased. The % cell death, including apoptosis and necrosis, was significantly lower in the lower volume method than in the conventional method. There were no significant differences between the lower volume and conventional methods in the expression levels of the neuronal marker genes. In an analysis of immunostaining for a mature neuronal marker, no significant difference was detected between the media volumes. These findings demonstrate that neuronal induction of MSCs in low volumes of differentiation medium promoted survival during differentiation and resulted in larger numbers of MSC-derived neurons, compared to the conventional method. This novel lower volume method offers both financial and cell-yield advantages over the conventional method.

Modern stem cell therapy: approach to disease

Various types of stem cells exist, each with their own advantages and disadvantages. Considering the current available evidence, important preclinical and clinical studies regarding the therapeutic potential of stem cells, stem cell therapy might be the important strategy for tissue repair. The development of stem cell therapy for tissue repair has primarily relied on stem cells, especially mesenchymal stem cells. Multilineage differentiation into all of the described cells are considered as important candidates for a range of diseases like neurological diseases, cardiovascular diseases, gastrointestinal cancer and genetic defects, as well as for acute and chronic wounds healing and pharmaceutical treatment. We review the properties and multipotency of stem cells and their differentiation potential, once cultured under specific growth conditions, for use in cell-based therapies and functional tissue replacement.

A Meta-Analysis of Mesenchymal Stem Cells in Animal Models of Parkinson's Disease

Multiple studies have been performed to evaluate the effects of mesenchymal stem cells (MSCs) in animal models of Parkinson's disease (PD). We performed a meta-analysis to estimate the treatment effect of unmodified MSCs on behavioral outcomes in preclinical studies of PD. We performed a systematic literature search to identify studies that used behavioral testing to evaluate the treatment effect of unmodified MSCs in PD models. Meta-analysis was used to determine pooled effect size for rotational behavior and limb function, and meta-regression was performed to explore sources of heterogeneity. Twenty-five studies, including three delivery routes, a wide range of doses, and multiple PD models, were examined. Significant improvement was seen in the pooled standardized mean difference (SMD) for both rotational behavior [SMD: 1.24, 95% confidence interval (95% CI): 0.84, 1.64] and limb function (SMD: 0.84, 95% CI: 0.01, 1.66). Using meta-regression, intravenous administration and higher dose had a larger effect on limb function. Treatment with MSCs improves behavioral outcomes in PD models. Our analyses suggest that MSCs could be considered for early-stage clinical trials in the treatment of PD.

Dopaminergic differentiation of stem cells from human deciduous teeth and their therapeutic benefits for Parkinsonian rats

Parkinson's disease (PD) is a progressive neurodegenerative disorder caused by the loss of nigrostriatal dopaminergic (DAergic) neurons and the depletion of striatal dopamine. Here we show that DAergic-neuron-like cells could be efficiently induced from stem cells derived from human exfoliated deciduous teeth (SHEDs), and that these induced cells had therapeutic benefits in a 6-OHDA-induced Parkinsonian rat model. In our protocol, EGF and bFGF signaling activated the SHED's expression of proneural genes, Ngn2 and Mash1, and subsequent treatment with brain-derived neurotrophic factor (BDNF) promoted their maturation into DAergic neuron-like SHEDs (dSHEDs). A hypoxic DAergic differentiation protocol improved cell viability and enhanced the expression of multiple neurotrophic factors, including BDNF, GDNF, NT-3, and HGF. Engrafted dSHEDs survived in the striatum of Parkinsonian rats, improved the DA level more efficiently than engrafted undifferentiated SHEDs, and promoted the recovery from neurological deficits. Our findings further suggested that paracrine effects of dSHEDs contributed to neuroprotection against 6-OHDA-induced neurodegeneration and to nigrostriatal tract restoration. In addition, we found that the conditioned medium derived from dSHEDs protected primary neurons against 6-OHDA toxicity and accelerated neurite outgrowth in vitro. Thus, our data suggest that stem cells derived from dental pulp may have therapeutic benefits for PD.

Intrastriatal transplantation of adult human neural crest-derived stem cells improves functional outcome in parkinsonian rats

Parkinson's disease (PD) is considered the second most frequent and one of the most severe neurodegenerative diseases, with dysfunctions of the motor system and with nonmotor symptoms such as depression and dementia. Compensation for the progressive loss of dopaminergic (DA) neurons during PD using current pharmacological treatment strategies is limited and remains challenging. Pluripotent stem cell-based regenerative medicine may offer a promising therapeutic alternative, although the medical application of human embryonic tissue and pluripotent stem cells is still a matter of ethical and practical debate. Addressing these challenges, the present study investigated the potential of adult human neural crest-derived stem cells derived from the inferior turbinate (ITSCs) transplanted into a parkinsonian rat model. Emphasizing their capability to give rise to nervous tissue, ITSCs isolated from the adult human nose efficiently differentiated into functional mature neurons in vitro. Additional successful dopaminergic differentiation of ITSCs was subsequently followed by their transplantation into a unilaterally lesioned 6-hydroxydopamine rat PD model. Transplantation of predifferentiated or undifferentiated ITSCs led to robust restoration of rotational behavior, accompanied by significant recovery of DA neurons within the substantia nigra. ITSCs were further shown to migrate extensively in loose streams primarily toward the posterior direction as far as to the midbrain region, at which point they were able to differentiate into DA neurons within the locus ceruleus. We demonstrate, for the first time, that adult human ITSCs are capable of functionally recovering a PD rat model.

Fibroblast Growth Factor-2 alone as an efficient inducer for differentiation of human bone marrow mesenchymal stem cells into dopaminergic neurons

Background

The reported efficiency of differentiation of human bone marrow derived Mesenchymal Stem Cells (hBM MSC) into dopaminergic neurons with different inducers is found to vary. Thus, in the current study we have investigated the response of hBM MSC to some of the neuronal inducers and their combinations. Neuronal differentiation inducing agents Fibroblastic Growth Factor 2 (FGF2), Sonic Hedge Hog (Shh), Fibroblastic Growth Factor 8 (FGF8) & All Trans Retinoic Acid (ATRA) were used either singly or in varied combinations.

Results

The differentiated and undifferentiated hBM MSC were characterized in terms of morphology, expression of cell markers at transcriptional and translational levels, amount of dopamine secreted by the cells in the media and changes in cell membrane potential by calcium ions imaging. Induced hBM MSC revealed neuron like morphology and expressed cellular markers suggesting neuronal differentiation with all the inducing agents. However, upon quantitative analysis through qPCR, cells induced with FGF2 were found to show maximum expression of tyrosine hydroxylase (TH) by 47.5 folds. Immunofluorescence analysis of differentiated and undifferentiated cells also revealed expression of nestin, neurofilament, microtubule associated protein- 2, beta tubulin III and TH in differentiated cells, at translational level. This data was supported by immunoblotting analysis. Further, ELISA study also supported the release of dopamine by cultures induced with FGF2. When the cells were depolarised with KCl solution, those induced with Shh & FGF8 showed maximum calcium ion trafficking, followed by the cells induced with FGF2 only.

Conclusions

We conclude that hBM MSC can be coaxed to differentiate efficiently into dopaminergic neurons in the presence of a very simple media cocktail containing only one main inducer like FGF2 and thus contribute towards cellular therapy in Parkinson's and other related disorders. These dopaminergic neurons are also functionally active, as shown by calcium ion trafficking.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-014-0083-1) contains supplementary material, which is available to authorized users.

Cell based therapies in Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder after Alzheimer’s disease. It is characterized by bradykinesia, hypokinesia/ akinesia, rigidity, tremor, and postural instability, caused by dopaminergic (DA) striatal denervation. The prevalence of PD increases from 50 years of age with steep rise after age 60 years. Current treatment of PD relies heavily on replacing lost dopamine either with its precursor L-dopa or dopamine agonists (ropinirole, pramipexole, bromocriptine, lisuride etc). Other pharmacological measures like catechol-O-methyltrasferase (COMT) inhibitors like entacopone, telcapone and monoamine oxidase B (MAO-B) inhibitors like selegiline and rasagiline are also useful, while L-dopa remains the gold standard in the treatment of PD. Emerging therapies are focusing on cell based therapeutics derived from various sources.

Transplantation of mesenchymal stem cells: a future therapy for Parkinson’s disease?

ABSTRACT: 

Parkinson’s disease (PD) is a common, progressive neurodegenerative disorder associated with a loss of dopaminergic cells in the substantia nigra pars compacta and a lack of dopamine in the striatum. To halt or reverse this disease, neurorestorative approaches or neuroprotective treatments are urgently needed. Recently, the first clinical trials transplanting mesenchymal stem cells (MSCs) have been performed in PD. MSCs are adult stem cells abundant in several tissues, such as the umbilical cord, the bone marrow, the adipose tissue and other tissues. These cells are multipotent, and able to synthesize and secrete a wide spectrum of biologically active factors. MSCs of various origins have been explored as possible substrates for cell therapy in PD animal models. In this review, we summarize MSC-based experimental transplantation studies in PD, and discuss biological mechanisms that may explain the effects of MSC seen in PD models. Furthermore, we critically evaluate the recent clinical transplantation trials using MSCs in patients with PD.

The potential of mesenchymal stem cells derived from amniotic membrane and amniotic fluid for neuronal regenerative therapy

The mesenchymal stem cells (MSCs), which are derived from the mesoderm, are considered as a readily available source for tissue engineering. They have multipotent differentiation capacity and can be differentiated into various cell types. Many studies have demonstrated that the MSCs identified from amniotic membrane (AM-MSCs) and amniotic fluid (AF-MSCs) are shows advantages for many reasons, including the possibility of noninvasive isolation, multipotency, self-renewal, low immunogenicity, anti-inflammatory and nontumorigenicity properties, and minimal ethical problem. The AF-MSCs and AM-MSCs may be appropriate sources of mesenchymal stem cells for regenerative medicine, as an alternative to embryonic stem cells (ESCs). Recently, regenerative treatments such as tissue engineering and cell transplantation have shown potential in clinical applications for degenerative diseases. Therefore, amnion and MSCs derived from amnion can be applied to cell therapy in neuro-degeneration diseases. In this review, we will describe the potential of AM-MSCs and AF-MSCs, with particular focus on cures for neuronal degenerative diseases.

Adipocytes derived from PA6 cells reliably promote the differentiation of dopaminergic neurons from human embryonic stem cells

The PA6 stromal cell line comprises a heterogeneous population of cells that can induce both mouse and human embryonic stem cells to differentiate into dopaminergic neurons. This ability of PA6 cells has been termed stromal cell-derived inducing activity (SDIA). The level of SDIA has been found to vary considerably between and within batches of PA6 cells. Not only are the molecular mechanisms that underlie SDIA unknown but also the cell type(s) within the heterogeneous PA6 cultures that underlie SDIA remain poorly defined. In this study, we reveal that adipocytes, which are present within the heterogeneous PA6 cell population, robustly release the factors mediating SDIA. Furthermore, we report that the coculture of human embryonic stem cells with PA6-derived adipocytes reliably induces their differentiation into midbrain dopaminergic neurons.

Immortalization of neuronal progenitors using SV40 large T antigen and differentiation towards dopaminergic neurons

Transplantation is common in clinical practice where there is availability of the tissue and organ. In the case of neurodegenerative disease such as Parkinson's disease (PD), transplantation is not possible as a result of the non-availability of tissue or organ and therefore, cell therapy is an innovation in clinical practice. However, the availability of neuronal cells for transplantation is very limited. Alternatively, immortalized neuronal progenitors could be used in treating PD. The neuronal progenitor cells can be differentiated into dopaminergic phenotype. Here in this article, the current understanding of the molecular mechanisms involved in the differentiation of dopaminergic phenotype from the neuronal progenitors immortalized with SV40 LT antigen is discussed. In addition, the methods of generating dopaminergic neurons from progenitor cells and the factors that govern their differentiation are elaborated. Recent advances in cell-therapy based transplantation in PD patients and future prospects are discussed.

Neuronal cell differentiation of mesenchymal stem cells originating from canine amniotic fluid

The amniotic fluid contains mesenchymal stem cells (MSCs) and can be readily available for tissue engineering. Regenerative treatments such as tissue engineering, cell therapy, and transplantation show potential in clinical trials of degenerative diseases. Disease presentation and clinical responses in the Canis familiaris not only are physiologically similar to human compared with other traditional mammalian models but is also a suitable model for human diseases. The aim of this study was to investigate whether canine amniotic-fluid-derived mesenchymal stem cells (cAF-MSCs) can differentiate into neural precursor cells in vitro when exposed to neural induction reagent. During neural differentiation, cAF-MSCs progressively acquire neuron-like morphology. Messenger RNA (mRNA) expression levels of neural-specific genes, such as NEFL, NSE, and TUBB3 (βIII-tubulin) dramatically increased in the differentiated cAF-MSCs after induction. In addition, protein expression levels of nestin, βIII-tubulin, and tyrosine hydroxylase remarkably increased in differentiated cAF-MSCs. This study demonstrates that cAF-MSCs have great potential for neural precursor differentiation in vitro. Therefore, amniotic fluid may be a suitable alternative source of stem cells and can be applied to cell therapy in neurodegenerative diseases.

Suppression of cancer-initiating cells and selection of adipose-derived stem cells cultured on biomaterials having specific nanosegments

Cancer-initiating cells [cancer stem cells (CSCs)] in colon cancer cells can be selectively suppressed when they are cultured on Pluronic (nanosegment)-grafted dishes, whereas CSCs are maintained on conventional tissue culture dishes and extracellular matrix-coated dishes. CSCs persist in tumors as a distinct population and cause relapse and metastasis by giving rise to new tumorigenic clones. The purification or depletion (suppression) of CSCs should be useful for analyzing CSC characteristics and for clinical application. CSCs can be selectively suppressed from colon cancer cells containing adipose-derived stem cells (ADSCs) on Pluronic-grafted dishes, while ADSCs remain on the dishes. ADSCs on Pluronic-grafted dishes after the suppression of the CSCs can differentiate into osteoblasts, chondrocytes, adipocytes, cardiomyocytes, and neuronal cells. The CSCs and ADSCs exhibited different characteristics. The selection of ADSCs was possible on Pluronic-grafted dishes that suppressed the CSCs from the fat tissues of cancer patients (i.e., cell-sorting dishes), which was explained by specific biomedical characteristics of Pluronic.

bFGF promotes the differentiation and effectiveness of human bone marrow mesenchymal stem cells in a rotenone model for Parkinson's disease

Previous studies have shown that bone marrow mesenchymal stem cells (BMSCs) engraftment could alleviate motor dysfunction in parkinsonian animal models, but with limited efficacy and few engrafted cells surviving. On the other side, basic fibroblast growth factor (bFGF) reportedly displays many effects including neuroprotection and promoting multipotent cells to expand and differentiate. In this study, we assessed whether a combination of bFGF and human BMSCs (HBMSCs) therapy could enhance the treatment effectiveness in Parkinson's disease (PD) rat models. Specifically, bFGF promoted HBMSCs to transdifferentiate toward neural-like lineages in vitro. In addition, HBMSCs transplantation alleviated the motor functional asymmetry, as well as prevented dopaminergic neuron loss in a PD model, while bFGF administration enhances its neurodifferentiation capacity and therapeutic effect. In conclusion, optimizing culture condition like supplementation of bFGF could significantly improve the output of HBMSCs in vitro, and HBMSCs transplantation with bFGF might represent an improved transplantation approach for PD.

Cell based therapy in Parkinsonism

Parkinson's disease (PD) is a synucleinopathy-induced chronic progressive neurodegenerative disorder, worldwide affecting about 5 million humans. As of yet, actual therapies are symptomatic, and neuroprotective strategies are an unmet need. Due to their capability to transdifferentiate, to immune modulate and to increase neuroplasticity by producing neurotrophic factors, adult stem cells (ASC) might fill this gap. Preclinical research in 6-hydroxydopamine (6-OHDA) and/or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) lesioned animals established persistent improvements of motor behavior after ASC-treatment. Histological/histochemical measurements in these animals evidenced an intracerebral applied ASC-induced increase of Tyrosine Hydroxylase-positive (TH+) cells with increased striatal dopamine levels, suggesting cell rescue. Likewise, clinical experience with subventricular applied ASCs in PD patients, although limited, is encouraging, evidencing neurorescue especially during the early phase of the disease. In multiple system atrophy (MSA) or progressive supranuclear palsy (PSP) patients, though, only marginal reduced progression of natural progression could be established after subventricular or intravasal ASC implantations.