Induction of adipose-derived stem cell into motoneuron-like cells using selegiline as preinducer. Brain Res. 2012;1440:23-33. [PMID: 22284617 DOI: 10.1016/j.brainres.2011.12.051]

Differentiation of human dental pulp stem cells into functional motor neuron: In vitro and ex vivo study

There are several therapeutic options for spinal cord injury (SCI), among these strategies stem cell therapy is a potential treatment. The stem cells based therapies have been investigating in acute phase of clinical trials for promoting spinal repair in humans through replacement of functional neuronal and glial cells. The aim of this study was to evaluate the differentiation of Human Dental Pulp Stem Cells (hDPSCs) into functional motor neuron like cells (MNLCs) and promote neuroregeneration by stimulating local neurogenesis in the adult spinal cord slice culture. The immunocytochemistry analysis demonstrated that hDPSCs were positive for mesenchymal stem cell markers (CD73, CD90 and CD105) and negative for the hematopoietic markers (CD34 and CD45). hDPSCs were induced to neurospheres (via implementing B27, EGF, and bFGF) and then neural stem cells (NSC). The NSC differentiated into MNLCs in two steps: first by Shh and RA and ; then with GDNF and BDNF administration. The NS and the NSC were assessed for Oct4, nestin, Nanog, Sox2 expression while the MNLCs were evaluated by ISLET1, Olig2, and HB9 genes. Our results showed that hDPSC can be differentiated into motor neuron phenotype with expression of the motor neuron genes. The functionality of MNLCs was demonstrated by FM1-43, intracellular calcium ion shift and co- culture with C2C12. We co-cultivated hDPSCs with adult rat spinal slices in vitro. Immunostaining and hoechst assay showed that hDPSCs were able to migrate, proliferate and integrate in both the anterolateral zone and the edges of the spinal slices.

[Research progress of adipose-derived stem cells in promoting the repair of peripheral nerve injury]

OBJECTIVE

To summarize the research progress of adipose-derived stem cells (ADSCs) in promoting the repair of peripheral nerve injury.

METHODS

The related literature at home and abroad in recent years was widely reviewed, the mechanism of ADSCs promoting the repair of peripheral nerve injury was introduced, and its basic research progress was analyzed and summarized. Finally, the clinical transformation application of ADSCs in the treatment of peripheral nerve injury was introduced, the existing problems were pointed out, and the new treatment regimen was prospected.

RESULTS

ADSCs have the function of differentiation and paracrine, and their secreted neurotrophic factors, antiapoptosis, and antioxidant factors can promote the repair of peripheral nerve injury.

CONCLUSION

ADSCs are rich in content and easy to obtain, which has a definite effectiveness on the repair of peripheral nerve injury with potential clinical prospect.

Comparison of the proteome patterns of adipose-derived stem cells with those treated with selegiline using a two dimensional gel electrophoresis analysis

Adipose derived stem cells (ADSCs) are multipotent and can transdifferentiate into neural stem cells. We investigated the transdifferentiation of ADSCs to neural phenotype (NP) cells using selegiline and two-dimensional electrophoresis (2-DE). The perinephric and inguinal fat of rats was collected and used to isolate ADSCs that were characterized by immunophenotyping using flow cytometry. The ADSCs were differentiated into osteogenic and lipogenic cells. The NP cells were generated using 10^-9 mM selegiline and characterized by immunocytochemical staining of nestin and neurofilament 68 (NF-68), and by qRT-PCR of nestin, neurod1 and NF68. Total protein of ADSCs and NP cells was extracted and their proteome patterns were examined using 2-DE. ADSCs carried CD73, CD44 and CD90 cell markers, but not CD34. ADSCs were differentiated into osteocyte and adipocyte lineages. The differentiated NP cells expressed nestin, neuro d1 and NF-68. The proteome pattern of ADSCs was compared with that of NP cells and eight spots showed more than a two fold increase in protein expression. The molecular weights and isoelectric points of these highly expressed proteins were estimated using Melanie software. We compared these results with those of the mouse proteomic database using the protein isoelectric point database, and the functions of the eight proteins in differentiation of NP cells were predicted using the UniProt database. The probable identities of the proteins that showed higher expression in NP cells included cholinesterase, GFRa2, protein kinase C (PKC-eta) and RING finger protein 121. The sequences of the proteins identified from mouse database were aligned by comparing them with similar proteins in rat database using the Basic Local Alignment Search Tool (BLAST). The E values of all aligned proteins were zero, which indicates consistency of the matched protein. These proteins participate in differentiation of the neuron and their overexpression causes ADSCs transdifferentiation into NP cells.

Differentiation of human adipose-derived stem cells into neuron/motoneuron-like cells for cell replacement therapy of spinal cord injury

Human adipose-derived stem cells (hADSCs) are increasingly presumed to be a prospective stem cell source for cell replacement therapy in various degenerative and/or traumatic diseases. The potential of trans-differentiating hADSCs into motor neuron cells indisputably provides an alternative way for spinal cord injury (SCI) treatment. In the present study, a stepwise and efficient hADSC trans-differentiation protocol with retinoic acid (RA), sonic hedgehog (SHH), and neurotrophic factors were developed. With this protocol hADSCs could be converted into electrophysiologically active motoneuron-like cells (hADSC-MNs), which expressed both a cohort of pan neuronal markers and motor neuron specific markers. Moreover, after being primed for neuronal differentiation with RA/SHH, hADSCs were transplanted into SCI mouse model and they survived, migrated, and integrated into injured site and led to partial functional recovery of SCI mice. When ablating the transplanted hADSC-MNs harboring HSV-TK-mCherry overexpression system with antivirial Ganciclovir (GCV), functional relapse was detected by motor-evoked potential (MEP) and BMS assays, implying that transplanted hADSC-MNs participated in rebuilding the neural circuits, which was further confirmed by retrograde neuronal tracing system (WGA). GFP-labeled hADSC-MNs were subjected to whole-cell patch-clamp recording in acute spinal cord slice preparation and both action potentials and synaptic activities were recorded, which further confirmed that those pre-conditioned hADSCs indeed became functionally active neurons in vivo. As well, transplanted hADSC-MNs largely prevented the formation of injury-induced cavities and exerted obvious immune-suppression effect as revealed by preventing astrocyte reactivation and favoring the secretion of a spectrum of anti-inflammatory cytokines and chemokines. Our work suggests that hADSCs can be readily transformed into MNs in vitro, and stay viable in spinal cord of the SCI mouse and exert multi-therapeutic effects by rebuilding the broken circuitry and optimizing the microenvironment through immunosuppression.

Immunocytochemical analysis of valproic acid induced histone H3 and H4 acetylation during differentiation of rat adipose derived stem cells into neuron-like cells

Valproic acid (VPA) is an inhibitor of histone deacetylases (HDACs) that can regulate differentiation and proliferation of stem cells by epigenetic mechanisms. We investigated VPA induced histone H3 and H4 acetylation in adipose derived stem cells (ADSCs) transdifferentiated into neuron-like cells (NLCs). Rat ADSCs were transdifferentiated into neural stem cells (NSCs) that had been generated from neurospheres. The NSCs were differentiated into NLCs by induction with different concentrations of VPA at 24, 48 and 72 h. The NLCs were evaluated using anti-H3 and -H4 antibodies, and ADSCs, NSCs and NLCs were evaluated using immunofluorescence. The ADSCs were immunoreactive to CD90 and CD49d, but not to CD45 and CD31. Both the neurospheres and NSCs were immunostained with nestin and neurofilament 68. The neurospheres expressed Musashi1, Sox2 and Neu N genes as determined by RT-PCR. Our dose-response study indicated that the optimal concentration of VPA was 1 mM at 72 h. Histone acetylation levels of H3 and H4 immunostaining intensities in NLCs were significantly greater than for ADSCs and NSCs. VPA alters H4 and H3 acetylation immunoreactivities of ADSCs transdifferentiated into NLCs.

Neuroprotective effects of selegiline on rat neural stem cells treated with hydrogen peroxide

Oxidative stress and reactive oxygen species generation have been implicated in the pathogenesis of several neurological disorders including Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis and multiple sclerosis. In the present study, the neuroprotective effects of selegiline against hydrogen peroxide-induced oxidative stress in hippocampus-derived neural stem cells (NSCs) were evaluated. NSCs isolated from neonatal Wistar rats were pretreated with different doses of selegiline for 48 h and then exposed to 125 µM H2O2 for 30 min. Using MTT and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays, acridine orange/ethidium bromide staining and reverse transcription-quantitative polymerase chain reaction, the effects of selegiline on cell survival, apoptosis and the expression of B-cell lymphoma 2 (Bcl-2) and heat shock protein 4 (Hspa4) in pretreated stem cells were assessed compared with a control group lacking pretreatment. The results indicated that the viability of cells pretreated with 20 µM selegiline was significantly increased compared with the control group (P<0.05). Additionally, 20 µM selegiline increased the mRNA expression of Bcl-2 and Hspa4 (P<0.05 vs. control) and suppressed oxidative stress-induced cell death (apoptosis and necrosis; P<0.05 vs. control and 10 µM groups). From these findings, it was concluded that selegiline may be a therapeutic candidate for the treatment of neurological diseases mediated by oxidative stress.

Advances, challenges and future directions for stem cell therapy in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative condition where loss of motor neurons within the brain and spinal cord leads to muscle atrophy, weakness, paralysis and ultimately death within 3–5 years from onset of symptoms. The specific molecular mechanisms underlying the disease pathology are not fully understood and neuroprotective treatment options are minimally effective.

In recent years, stem cell transplantation as a new therapy for ALS patients has been extensively investigated, becoming an intense and debated field of study. In several preclinical studies using the SOD1^G93A mouse model of ALS, stem cells were demonstrated to be neuroprotective, effectively delayed disease onset and extended survival. Despite substantial improvements in stem cell technology and promising results in preclinical studies, several questions still remain unanswered, such as the identification of the most suitable and beneficial cell source, cell dose, route of delivery and therapeutic mechanisms. This review will cover publications in this field and comprehensively discuss advances, challenges and future direction regarding the therapeutic potential of stem cells in ALS, with a focus on mesenchymal stem cells. In summary, given their high proliferation activity, immunomodulation, multi-differentiation potential, and the capacity to secrete neuroprotective factors, adult mesenchymal stem cells represent a promising candidate for clinical translation. However, technical hurdles such as optimal dose, differentiation state, route of administration, and the underlying potential therapeutic mechanisms still need to be assessed.

The Influence of AGEs Environment on Proliferation, Apoptosis, Homeostasis, and Endothelial Cell Differentiation of Human Adipose Stem Cells

The aim of this study was to evaluate the changes of proliferation, apoptosis, homeostasis, and differentiation of human adipose-derived stem cells (hASCs) in the simulated diabetic microenvironment and discuss the potential of the mesenchymal stem cell in the treatment of chronic diabetic wound. We simulated diabetic microenvironment with glycation end products (AGEs) in vitro and studied the changes of hASCs in proliferation and apoptosis. We found that AGEs inhibited the proliferation and lead to hASCs apoptosis, and the endothelial cell directed differentiation was also inhibited. AGEs upregulated growth-related oncogene and monocyte chemoattractant protein-1 and downregulated urokinase-type plasminogen activator receptor, which may inhibit the proliferation and transference of endothelial cells. The simulated diabetic microenvironment affects the proliferation, apoptosis, and homeostasis of hASCs, the endothelial cell migration, and the synthesis of collagen protein, leading to delayed wound healing.

Motor Neuron Transdifferentiation of Neural Stem Cell from Adipose-Derived Stem Cell Characterized by Differential Gene Expression

Adipose-derived stem cells (ADSC) are adult stem cells which can be induced into motor neuron-like cells (MNLC) with a preinduction-induction protocol. The purpose of this study is to generate MNLC from neural stem cells (NSC) derived from ADSC. The latter were isolated from the perinephric regions of Sprague-Dawley rats, transdifferentiated into neurospheres (NS) using B27, EGF, and bFGF. After generating NSC from the NS, they induced into MNLC by treating them with Shh and RA, then with GDNF, CNTF, BDNF, and NT-3. The ADSC lineage was evaluated by its mesodermal differentiation and was characterized by immunostaining with CD90, CD105, CD49d, CD106, CD31, CD45, and stemness genes (Oct4, Nanog, and Sox2). The NS and the NSC were evaluated by immunostaining with nestin, NF68, and Neurod1, while the MNLC were evaluated by ISLET1, Olig2, and HB9 genes. The efficiency of MNLC generation was more than 95 ± 1.4 % (mean ± SEM). The in vitro generated myotubes were innervated by the MNLC. The induced ADSC adopted multipolar motor neuron morphology, and they expressed ISLET1, Olig2, and HB9. We conclude that ADSC can be induced into motor neuron phenotype with high efficiency, associated with differential expression of the motor neuron gene. The release of MNLC synaptic vesicles was demonstrated by FM1-43, and they were immunostained with synaptophysin. This activity was correlated with the intracellular calcium ion shift and membrane depolarization upon stimulation as was demonstrated by the calcium indicator and the voltage-sensitive dye, respectively.

Facilitated Neural Differentiation of Adipose Tissue–Derived Stem Cells by Electrical Stimulation and Nurr-1 Gene Transduction

Neuron-like cells derived from adipose tissue-derived stem cells (ADSCs) have been considered one of the most promising cells for the treatment of neurodegenerative diseases and neurotrauma in the central nervous system (CNS). Thus far, extensive efforts have been made to facilitate neuronal differentiation of ADSCs, but limited progress has been achieved. In the present study, we tested the possibility of using a combination of electrical stimulation (ES) with Nurr-1 gene transduction to promote neuronal differentiation of ADSCs. The tolerance of ADSCs to ES was first examined by a cell apoptosis assay. The proliferation of cells was characterized using a CCK-8 assay. The morphology of cells was examined by scanning electron microscopy (SEM). The differentiation of ADSCs into neuron-like cells was examined by immunocytochemistry (ICC)–immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, and enzyme linked immunosorbent assay (ELISA). The gene expression of microtubule-associated protein 2 (MAP-2), β-tubulin, neurofilament 200 (NF-200), octamer binding transcription factor 4 (OCT-4), and glial fibrillary acidic protein (GFAP) after stimulation was examined by qRT-PCR. We found that the optimal intensity of ES for neuronal differentiation of ADSCs was 1 V/cm. In addition, ES combined with Nurr-1 gene transduction increased the neuronal differentiation rate of ADSCs, the length of neurite-like processes, and the secretion of dopamine. Further studies showed that a combination of ES with Nurr-1 gene transduction was capable of promoting the expression of MAP-2, β-tubulin, and NF-200 but decreased the expression of OCT-4 and GFAP. All of these findings indicate that a combination of ES with Nurr-1 gene transduction could facilitate neuronal differentiation of ADSCs, which raises the possibility of its application in the treatment of neurodegenerative diseases and neurotrauma in the CNS.

Creatine Enhances Transdifferentiation of Bone Marrow Stromal Cell-Derived Neural Stem Cell Into GABAergic Neuron-Like Cells Characterized With Differential Gene Expression

Creatine was reported to induce bone marrow stromal cells (BMSC) into GABAergic neuron-like cells (GNLC). In a previous study, creatine was used as a single inducer for BMSC into GNLC with low yield. In this study, BMSC-derived neurospheres (NS) have been used in generating GABAergic phenotype. The BMSC were isolated from adult rats and used in generating neurospheres and used for producing neural stem cells (NSC). A combination of all-trans-retinoic acid (RA), the ciliary neurotrophic factor (CNTF), and creatine was used in order to improve the yield of GNLC. We also used other protocols for the transdifferentiation including RA alone; RA and creatine; RA and CNTF; and RA, CNTF, and creatine. The BMSC, NSC, and GNLC were characterized by specific markers. The activity of the GNLC was evaluated using FM1-43. The isolated BMSC expressed Oct4, fibronectin, and CD44. The NS were immunoreactive to nestin and SOX2, the NSC were immunoreactive to nestin, NF68 and NF160, while the GNLC were immunoreactive to GAD1/2, VGAT, GABA, and synaptophysin. Oct4 and c-MYC, pluripotency genes, were expressed in the BMSC, while SOX2 and c-MYC were expressed in the NSC. The activity of GNLC indicates that the synaptic vesicles were released upon stimulation. The conclusion is that the combination of RA, CNTF, and creatine induced differentiation of neurosphere-derived NSC into GNLC within 1 week. This protocol gives higher yield than the other protocols used in this study. The mechanism of induction was clearly associated with several differential pluripotent genes.

Nerve defect repair by differentiated adipose-derived stem cells and chondroitinase ABC-treated acellular nerves

OBJECTIVE

To evaluate the effects of differentiated adipose-derived stem cells (dADSC) and chondroitinase ABC (ChABC)-treated acellular nerves (ACN) in building artificial nerves and repairing nerve defects.

METHODS

ADSC were isolated from the adipose tissue of Wistar rats, induced to differentiate into Schwann-like cells, and implanted into ChABC-treated ACN to repair a 15-mm sciatic nerve defect in Sprague-Dawley rats (the experimental group, group D). The control groups were an autologous nerve transplantation group (group E); ACN (group A), ChABC-treated ACN graft group (group B), and dADSC + ACN (group C). Twelve weeks after surgery, electromyography recordings, tricep surae muscle wet weight recovery rate, and axon counts were measured to evaluate the repair of peripheral nerve defects.

RESULTS

The nerve conduction velocity, compound muscle action potentials, tricep surae muscle wet weight recovery rate, and myelinated axon counts in the ChABC-ACN/dADSC group were significantly higher than in the other groups (P < 0.05), which were all lower than the autologous group (P < 0.05).

CONCLUSIONS

The combination of ChABC-treated ACN and dADSC exhibited a synergistic effect in promoting nerve regeneration, and could be an alternative for effective tissue-engineered nerves.

Intraspinal transplantation of motoneuron-like cell combined with delivery of polymer-based glial cell line-derived neurotrophic factor for repair of spinal cord contusion injury

To evaluate the effects of glial cell line-derived neurotrophic factor transplantation combined with adipose-derived stem cells-transdifferentiated motoneuron delivery on spinal cord contusion injury, we developed rat models of spinal cord contusion injury, 7 days later, injected adipose-derived stem cells-transdifferentiated motoneurons into the epicenter, rostral and caudal regions of the impact site and simultaneously transplanted glial cell line-derived neurotrophic factor-gelfoam complex into the myelin sheath. Motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery reduced cavity formations and increased cell density in the transplantation site. The combined therapy exhibited superior promoting effects on recovery of motor function to transplantation of glial cell line-derived neurotrophic factor, adipose-derived stem cells or motoneurons alone. These findings suggest that motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery holds a great promise for repair of spinal cord injury.

Differentiation of neurosphere-derived rat neural stem cells into oligodendrocyte-like cells by repressing PDGF-α and Olig2 with triiodothyronine

One of the approaches for treating demyelination diseases is cytotherapy, and adult stem cells are potential sources. In this investigation, we tried to increase the yield of oligodendrocyte-like cells (OLCs) by inducing neural stem cells generated from BMSCs-derived neurospheres, which were used for deriving the neural stem cells (NSCs). The latter were induced into OLCs by heregulin, PDGF-AA, bFGF and triiodothyronine (T3). The BMSCs, NS, NSCs and OLCs were characterized by using immunocytochemistry for fibronectin, CD44, CD90, CD45, Oct-4, O4, Olig2, O1 and MBP markers. PDGF receptor α (PDGFR-α), Olig2 and MOG expression were evaluated by RT-PCR. The BMSCs expressed CD44, CD90, CD106 and Oct-4; the NSCs were immunoreactive to nestin and neurofilament 68. Incubation of the NSCs for 4 days with heregulin, PDGF-AA and bFGF resulted in their induction into oligodendrocyte progenitor-like cells (OPLCs), which immunoreacted to O4, Olig2 and O1, while Olig2 and PDGFR-α were detected by RT-PCR. Replacing heregulin, PDGF-AA and bFGF with T3 for 6 days resulted in repression of O4, O1, Olig2 and PDGFR-α. The OLCs were co-cultured with motoneurons resulted in induction of MOG and MBP, which were expressed in functional OLCs. The latter can be generated from BMSCs-derive NS with high yield.

Regenerative therapy for neuronal diseases with transplantation of somatic stem cells

Pluripotent stem cells, which are capable of differentiating in various species of cells, are hoped to be donor cells in transplantation in regenerative medicine. Embryonic stem (ES) cells and induced pluripotent stem cells have the potential to differentiate in approximately all species of cells. However, the proliferating ability of these cells is high and the cancer formation ability is also recognized. In addition, ethical problems exist in using ES cells. Somatic stem cells with the ability to differentiate in various species of cells have been used as donor cells for neuronal diseases, such as amyotrophic lateral sclerosis, spinal cord injury, Alzheimer disease, cerebral infarction and congenital neuronal diseases. Human mesenchymal stem cells derived from bone marrow, adipose tissue, dermal tissue, umbilical cord blood and placenta are usually used for intractable neuronal diseases as somatic stem cells, while neural progenitor/stem cells and retinal progenitor/stem cells are used for a few congenital neuronal diseases and retinal degenerative disease, respectively. However, non-treated somatic stem cells seldom differentiate to neural cells in recipient neural tissue. Therefore, the contribution to neuronal regeneration using non-treated somatic stem cells has been poor and various differential trials, such as the addition of neurotrophic factors, gene transfer, peptide transfer for neuronal differentiation of somatic stem cells, have been performed. Here, the recent progress of regenerative therapies using various somatic stem cells is described.

Characterization of in vitro cultured bone marrow and adipose tissue-derived mesenchymal stem cells and their ability to express neurotrophic factors

MSCs (mesenchymal stem cells) have attracted attention as a promising tool for regenerative medicine and transplantation therapy. MSCs exert neuroprotective effects by secreting a number of factors in vitro and in vivo. Similar characteristics are found in ADSCs (adipose-derived stem cells) and BMSCs (bone marrow stromal cells). Multipotent capability, easy accessibility and rapid proliferation of ADSCs have been established. Our main objective was to compare cell viability, growth rate, expression of neurotrophic factors and nestin genes in ADSCs and BMSCs. Cell doubling time and proliferation rate indicate that ADSCs has a higher proliferation rate than BMSCs. ADSCs and BMSCs express a similar pattern of CD71 and CD90 markers. Nestin immunostaining showed that ADSCs and BMSCs are immunopositive. The expression of neurotrophic factors genes in ADSCs proved similar to that of BMSCs genes. Thus adipose tissue stem cells with a high proliferation rate can express nestin and neurotrophic factor genes. Therefore ADSCs may be useful in future cell replacement therapies and help improve neurodegenerative diseases.

Tyrosine hydroxylase: human isoforms, structure and regulation in physiology and pathology

TH is a tetrahydrobiopterin-requiring, iron-containing monooxygenase. It catalyses the conversion of L-tyrosine to L-dopa, which is the first, rate-limiting step in the biosynthesis of catecholamines (dopamine, noradrenaline and adrenaline), the central and sympathetic neurotransmitters and adrenomedullary hormones. The cofactor of TH is tetrahydrobiopterin, which is synthesized from GTP in three steps. The TH gene consists of 14 exons only in humans and 13 exons in animals. Human TH exists in four isoforms (hTH1-4) that are produced by alternative mRNA splicing from a single gene. A single mRNA and protein corresponding to hTH1 exists in non-primates. Monkey TH exists in two isoforms, corresponding to hTH1 and hTH2. TH activity is regulated in the short term by feedback inhibition of catecholamines in competition with tetrahydrobiopterin, and by activation and deactivation due to phosphorylation and dephosphorylation, mainly at Ser-19 and Ser-40 of hTH1. The multiple TH isoforms in humans and monkeys have additional phosphorylation, resulting in more subtle regulation. In long-term regulation under stress conditions, TH protein is induced. CRE and AP1 in the 5' flanking region of the TH gene may be the main functional elements for TH gene expression. TH may be closely related to the pathogenesis of neurological diseases, such as dystonia and Parkinson's disease, psychiatric diseases, such as affective disorders and schizophrenia, as well as cardiovascular diseases. The TH gene may prove useful in gene therapy to compensate for decreased levels of catecholamines in neurological diseases, for example, for supplementation of dopamine in Parkinson's disease.