Proliferation Of Endogenous Neural Stem Cells Research Articles

Neurophilic peptide-reinforced dual-fiber-network bioactive hydrogels for spinal cord injury repair

Spinal cord injury (SCI) is a challenging central nervous system disorder that characterized by microenvironmental disturbances following injury, which can be addressed by simulating the microenvironment of the spinal cord regeneration. Herein, we report the design and synthesis of bioactive hydrogels with a dual-fiber-network (DFN) porous structure, using self-assembled peptide nanofibers (PNFs) and natural cellulose nanofibers (CNFs). A neurophilic peptide is further introduced to enhance nervous regeneration capability of the pre-prepared PNF/CNF hydrogels, which then exhibit excellent neuro-affinity, self-healing ability, biodegradability, and biocompatibility, facilitating targeted SCI repair and regeneration through the hydrogel injection. The in vitro experiments reveal that the DFN hydrogel can enhance the proliferation and migration of bone marrow mesenchymal stem cells, and induce neural stem cell (NSC) proliferation with enhanced neuronal differentiation and axonal growth. Additionally, the in vivo studies validate that the hydrogel attenuates the post-SCI inflammation, inhibits reactive astrocyte proliferation, and facilitates endogenous NSC proliferation and migration, as well as promotes neuronal growth and axonal regeneration. The potential mechanism of SCI repair is ascribed to the hydrogel-induced activation of the PI3K/AKT/mTOR pathway, which alleviates inflammatory response, inhibits excessive reactive response of glial cells, and promotes NSC differentiation into neurons. This neurophilic peptide-reinforced DFN bioactive hydrogel system, with its comprehensive approach to SCI repair, holds great potential for clinical applications.

Metformin enhances endogenous neural stem cells proliferation, neuronal differentiation, and inhibits ferroptosis through activating AMPK pathway after spinal cord injury

BackgroundInadequate nerve regeneration and an inhibitory local microenvironment are major obstacles to the repair of spinal cord injury (SCI). The activation and differentiation fate regulation of endogenous neural stem cells (NSCs) represent one of the most promising repair approaches. Metformin has been extensively studied for its antioxidative, anti-inflammatory, anti-aging, and autophagy-regulating properties in central nervous system diseases. However, the effects of metformin on endogenous NSCs remains to be elucidated.MethodsThe proliferation and differentiation abilities of NSCs were evaluated using CCK-8 assay, EdU/Ki67 staining and immunofluorescence staining. Changes in the expression of key proteins related to ferroptosis in NSCs were detected using Western Blot and immunofluorescence staining. The levels of reactive oxygen species, glutathione and tissue iron were measured using corresponding assay kits. Changes in mitochondrial morphology and membrane potential were observed using transmission electron microscopy and JC-1 fluorescence probe. Locomotor function recovery after SCI in rats was assessed through BBB score, LSS score, CatWalk gait analysis, and electrophysiological testing. The expression of the AMPK pathway was examined using Western Blot.ResultsMetformin promoted the proliferation and neuronal differentiation of NSCs both in vitro and in vivo. Furthermore, a ferroptosis model of NSCs using erastin treatment was established in vitro, and metformin treatment could reverse the changes in the expression of key ferroptosis-related proteins, increase glutathione synthesis, reduce reactive oxygen species production and improve mitochondrial membrane potential and morphology. Moreover, metformin administration improved locomotor function recovery and histological outcomes following SCI in rats. Notably, all the above beneficial effects of metformin were completely abolished upon addition of compound C, a specific inhibitor of AMP-activated protein kinase (AMPK).ConclusionMetformin, driven by canonical AMPK-dependent regulation, promotes proliferation and neuronal differentiation of endogenous NSCs while inhibiting ferroptosis, thereby facilitating recovery of locomotor function following SCI. Our study further elucidates the protective mechanism of metformin in SCI, providing new mechanistic insights for its candidacy as a therapeutic agent for SCI.

Adult neurogenesis: a real hope or a delusion?

Adult neurogenesis, the process of creating new neurons, involves the coordinated division, migration, and differentiation of neural stem cells. This process is restricted to neurogenic niches located in two distinct areas of the brain: the subgranular zone of the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricle, where new neurons are generated and then migrate to the olfactory bulb. Neurogenesis has been thought to occur only during the embryonic and early postnatal stages and to decline with age due to a continuous depletion of neural stem cells. Interestingly, recent years have seen tremendous progress in our understanding of adult brain neurogenesis, bridging the knowledge gap between embryonic and adult neurogenesis. Here, we discuss the current status of adult brain neurogenesis in light of what we know about neural stem cells. In this notion, we talk about the importance of intracellular signaling molecules in mobilizing endogenous neural stem cell proliferation. Based on the current understanding, we can declare that these molecules play a role in targeting neurogenesis in the mature brain. However, to achieve this goal, we need to avoid the undesired proliferation of neural stem cells by controlling the necessary checkpoints, which can lead to tumorigenesis and prove to be a curse instead of a blessing or hope.

Phenylethanoid glycosides derived from Cistanche deserticola promote neurological functions and the proliferation of neural stem cells for improving ischemic stroke

Phenylethanoid glycosides derived from Cistanche deserticola (PhGs) are plant-derived natural medicinal compounds that occur in many medicinal plants. This study aims to investigate whether PhGs treatment improves the stroke and its potential mechanisms. Adult male C57BL/6 J mice were administrated PhGs once daily for 7 days after MCAO surgery. The neurological score, and catwalk were evaluated on Day 1, 3 and 7 after ischemic stroke. Furthermore, triphenyl-2,3,5-tetrazoliumchloride (TTC) and hematoxylin-eosin (H&E) staining were used for evaluating the infarct volume and neuronal restoration. The effects of PhGs on NSCs proliferation were investigated in vitro and in vivo. Western blot was used to detect the proteins of Wnt/β-catenin signaling pathway. This study found that PhGs effectively improved the neurological functions in ischemic stroke mice. TTC and H&E staining demonstrated that PhGs not only reduced infarct volume, but also improved neuronal restoration. The immunohistochemistry and 5-Ethynyl-2-deoxyuridine (EdU) incorporation assays revealed that PhGs promoted the proliferation of neural stem cells (NSCs) in subventricular zone (SVZ). In addition, transcriptome analysis of NSCs showed that the Wnt/β-catenin signaling pathway was involved in the PhGs induced NSCs proliferation. Importantly, the related proteins in the Wnt/β-catenin signaling pathway were changed after PhGs treatment, including β-catenin, Wnt3a, GSK-3β, c-Myc. PhGs treatment improved the stroke through enhancing endogenous NSCs proliferation via activating Wnt/β-catenin signaling pathway. Due to its effect on the proliferation of NSCs, PhGs are a potential adjuvant therapeutic drug for post-stroke treatment.

Effect of Electroacupuncture Stimulation on Proliferation and Differentiation of Endogenous Neural Stem Cells in Rats with Spinal Cord Injury.

The aim of this work was to investigate the effects of electroacupuncture (EA) stimulation on the proliferation and differentiation of endogenous neural stem cells (NSCs) in rats with spinal cord injury (SCI). One hundred rats were included and randomly divided into the sham-operation (SO) group, model (MO) group, EA group, and preacupuncture stimulation (PAS) group, with 25 rats in each group. All the rats in the SO group had their spinal cord of thoracic segment T10 exposed but without SCI. In the remaining three groups, the modified Allen's weight dropping method was adopted to make SCI models. Those in the SO group and the MO group did not receive any treatment. Those in the EA group were treated with EA after the modelling was completed, which stopped when the samples were collected at each time point. The spinal cord tissue of rats was subjected to immunohistochemical staining and real-time quantitative polymerase chain reaction (PCR) to detect the expressions of neurofilament nestin and glial fibrillary acidic protein (GFAP). The Basso-Beattie-Bresnahan (BBB) score of the MO group was much lower than that of the SO group on the 3rd, 7th, and 14th days after surgery (P < 0.05). The BBB scores of the EA group and PAS group were notably higher than that of the MO group (P < 0.05). The number of nestin-, GFAP-, and MAP-2-positive cells was significantly increased in rat tissues after spinal cord injury. On the 3rd, 7th, and 14th days postoperatively, the numbers of nestin-positive cells in the EA and PAS groups were considerably higher than those in the MO group (P < 0.01). However, the numbers of GFAP-positive cells in the EA and PAS groups were considerably decreased compared with those in the MO group (P < 0.01). The positive rate of MAP-2 in the model group was significantly increased compared to that in the sham-operation group (P < 0.001). The positive rates of MAP-2 in the EA group and PAS group were significantly higher than those in the MO group (P < 0.01). After spinal cord injury, EA could activate the proliferation of endogenous NSCs and promote their differentiation into neuronal cells. Consequently, injuries were repaired, and functions were rehabilitated.

Sanwei DouKou Decoction ameliorate Alzheimer disease by increasing endogenous neural stem cells proliferation through the Wnt/β-catenin signalling pathway.

Sanwei DouKou decoction (SDKD) is a traditional Chinese medicine (TCM) prescription derived from the Tibetan medical book "Si Bu Yi Dian" and is clinically used for the treatment of Alzheimer's disease (AD). However, the potential mechanism of SDKD treatment for AD remains elusive. This study aims to explore the potential mechanism by which SDKD alleviates AD. Extracts of SDKD were identified with Gas chromatograph-mass spectrometer (GC-MS). 5×FAD mice were treated with SDKD for 8 weeks. The efficacy of SDKD against AD was evaluated by in-vivo experiments. Morris water maze and contextual fear conditioning tests were used to detect the learning and memory ability of mice. Hematoxylin-eosin staining (H&E) staining was used to observe the pathological changes of brain tissue. Immunohistochemistry was used to detect the positive expression of Nestin in hippocampus. In in-vitro experiments, the Cell Counting Kit 8 (CCK-8) technique was used to detect cell viability, the proliferation of neural stem cells was detected by immunofluorescence staining, the intracellular protein expression was detected by Western Blot. The results of this study suggested that SDKD may ameliorate AD. SDKD significantly shortened the escape latency of mice in the Morris water maze experiment, increased the number of times the mice crossed the target quadrant, and prolonged freezing time in the contextual fear memory experiment. SDKD also improved neuronal pathology in the hippocampus, decreased neuronal loss, and increased Nestin protein levels. Furthermore, in in-vitro experiments, SDKD could significantly increase Neural stem cells (NSCs) viability, promoted NSCs proliferation, and also effectively activated the Wnt/β-catenin signalling pathway, increased Wnt family member 3A (Wnt3a), β-catenin and CyclinD1 protein levels, activated the NSCs proliferation pathways in AD model mouse brain tissue. The present study demonstrated that sanwei doukou decoction can ameliorate AD by increasing endogenous neural stem cells proliferation through the Wnt/β-catenin signalling pathway. Our observations justify the traditional use of SDKD for a treatment of AD in nervous system.

MiR-872-5p/FOXO3a/Wnt signaling feed-forward loop promotes proliferation of endogenous neural stem cells after spinal cord ischemia-reperfusion injury in rats.

The activation of endogenous neural stem cells (NSCs) is considered an important mechanism of neural repair after mechanical spinal cord injury; however, whether endogenous NSC proliferation can also occur after spinal cord ischemia-reperfusion injury (SCIRI) remains unclear. In this study, we aimed to verify the existence of endogenous NSC proliferation after SCIRI and explore the underlying molecular mechanism. NSC proliferation was observed after SCIRI in vivo and oxygen-glucose deprivation and reperfusion (OGD/R) in vitro, accompanied by a decrease in forkhead box protein O 3a (FOXO3a) expression. This downward trend was regulated by the increased expression of microRNA-872-5p (miR-872-5p). miR-872-5p affected NSC proliferation by targeting FOXO3a to increase the expression of β-catenin and T-cell factor 4 (TCF4). In addition, TCF4 in turn acted as a transcription factor to increase the expression level of miR-872-5p, and knockdown of FOXO3a enhanced the binding of TCF4 to the miR-872-5p promoter. In conclusion, SCIRI in vivo and OGD/R in vitro stimulated the miR-872-5p/FOXO3a/β-catenin-TCF4 pathway, thereby promoting NSC proliferation. At the same time, FOXO3a affected TCF4 transcription factor activity and miR-872-5p expression, forming a positive feedback loop that promotes NSC proliferation.

KAP1 phosphorylation promotes the survival of neural stem cells after ischemia/reperfusion by maintaining the stability of PCNA

AimsTo explore the function of phosphorylation of KAP1 (p-KAP1) at the serine-824 site (S824) in the proliferation and apoptosis of endogenous neural stem cells (NSCs) after cerebral ischemic/reperfusion (I/R).MethodsThe apoptosis and proliferation of C17.2 cells transfected with the p-KAP1-expression plasmids and the expression of proliferation cell nuclear antigen (PCNA) and p-KAP1 were detected by immunofluorescence and Western blotting after the Oxygen Glucose deprivation/reperfusion model (OGD/R). The interaction of p-KAP1 and CUL4A with PCNA was analyzed by immunoprecipitation. In the rats MCAO model, we performed the adeno-associated virus (AAV) 2/9 gene delivery of p-KAP1 mutants to verify the proliferation of endogenous NSCs and the colocalization of PCNA and CUL4A by immunofluorescence.ResultsThe level of p-KAP1 was significantly down-regulated in the stroke model in vivo and in vitro. Simulated p-KAP1(S824) significantly increased the proliferation of C17.2 cells and the expression of PCNA after OGD/R. Simulated p-KAP1(S824) enhanced the binding of p-KAP1 and PCNA and decreased the interaction between PCNA and CUL4A in C17.2 cells subjected to OGD/R. The AAV2/9-mediated p-KAP1(S824) increased endogenous NSCs proliferation, PCNA expression, p-KAP1 binding to PCNA, and improved neurological function in the rat MCAO model.ConclusionsOur findings confirmed that simulated p-KAP1(S824) improved the survival and proliferation of endogenous NSCs. The underlying mechanism is that highly expressed p-KAP1(S824) promotes binding to PCNA, and inhibits the binding of CUL4A to PCNA. This reduced CUL4A-mediated ubiquitination degradation to increase the stability of PCNA and promote the survival and proliferation of NSCs.

Apelin alleviated neuroinflammation and promoted endogenous neural stem cell proliferation and differentiation after spinal cord injury in rats

BackgroundSpinal cord injury (SCI) causes devastating neurological damage, including secondary injuries dominated by neuroinflammation. The role of Apelin, an endogenous ligand that binds the G protein-coupled receptor angiotensin-like receptor 1, in SCI remains unclear. Thus, our aim was to investigate the effects of Apelin in inflammatory responses and activation of endogenous neural stem cells (NSCs) after SCI.MethodsApelin expression was detected in normal and injured rats, and roles of Apelin in primary NSCs were examined. In addition, we used induced pluripotent stem cells (iPSCs) as a carrier to prolong the effective duration of Apelin and evaluate its effects in a rat model of SCI.ResultsCo-immunofluorescence staining suggested that Apelin was expressed in both astrocytes, neurons and microglia. Following SCI, Apelin expression decreased from 1 to 14 d and re-upregulated at 28 d. In vitro, Apelin promoted NSCs proliferation and differentiation into neurons. In vivo, lentiviral-transfected iPSCs were used as a carrier to prolong the effective duration of Apelin. Transplantation of transfected iPSCs in situ immediately after SCI reduced polarization of M1 microglia and A1 astrocytes, facilitated recovery of motor function, and promoted the proliferation and differentiation of endogenous NSCs in rats.ConclusionApelin alleviated neuroinflammation and promoted the proliferation and differentiation of endogenous NSCs after SCI, suggesting that it might be a promising target for treatment of SCI.

Promotion of Momordica Charantia polysaccharides on neural stem cell proliferation by increasing SIRT1 activity after cerebral ischemia/reperfusion in rats

The deacetylase SIRT1 has been reported to play a critical role in regulating neurogenesis, which may be an adaptive processes contributing to recovery after stroke. Our previous work showed that the antioxidant capacity of Momordica charantia polysaccharides (MCPs) could protect against cerebral ischemia/reperfusion (I/R) after stroke. However, whether the protective effect of MCPs on I/R injury is related to neural stem cell (NSC) proliferation remains unclear. In the present study, we designed invivo and invitro experiments to elucidate the underlying mechanisms by which MCPs promote endogenous NSC proliferation during cerebral I/R. Invivo results showed that MCPs rescued the memory and learning abilities of rats after I/R damage and enhanced NSC proliferation in the rat subventricular zone (SVZ) and subgrannular zone (SGZ) during I/R. Invitro experiments demonstrated that MCPs could stimulate the proliferation of C17.2 cells under oxygen-glucose deprivation (OGD) conditions. Further studies revealed that the proliferation-promoting mechanism of MCPs relied on increasing the activity of SIRT1, decreasing the level of acetylation of β-catenin in the cytoplasm, and then triggering the translocation of β-catenin into the nucleus. These data provide experimental evidence that the up-regulation of SIRT1 activity by MCPs led to an increased cytoplasmic deacetylation of β-catenin, which promoted translocation of β-catenin to the nucleus to participate in the signaling pathway involved in NSC proliferation. The present study reveals that MCPs function as a therapeutic drug to promote stroke recovery by increasing the activity of SIRT1, decreasing the level of acetylated β-catenin, promoting the nuclear translocation of β-catenin and thereby increasing endogenous NSC proliferation.

Intracerebroventricular Administration of hNSCs Improves Neurological Recovery after Cardiac Arrest in Rats.

Irreversible brain injury and neurological dysfunction induced by cardiac arrest (CA) have long been a clinical challenge due to lack of effective therapeutic interventions to reverse neuronal loss and prevent secondary reperfusion injury. The neuronal regenerative potential of neural stem cells (NSCs) provides a possible solution to this clinical deficit. We investigated the neuronal recovery potential of human neural stem cells (hNSCs) via intracerebroventricular (ICV) xenotransplantation after CA in rats and the effects of transplanted NSCs on the proliferation and migration of endogenous NSCs. Outcome measures included neurological functional recovery measured by neurological deficit score (NDS), electrophysiologic analysis of EEG, and assessment of proliferation and migration at the cellular level and the Wnt/β-catenin pathway at the molecular level. Neurological functional assessment based on aggregate neurological deficit score (NDS) showed better recovery of function after hNSCs therapy (P < 0.05). Tracking of stem cells' proliferation with Ki67 antibody suggested that the NSCs group had more prominent proliferation compared to control group (number of Ki67+ cells, Control VS. NSC: 89.0 ± 31.6 VS. 352.7 ± 97.3, P < 0.05). In addition, cell migration tracked by Dcx antibody showed more Dcx + cells migrated to the far distance zone from SVZ in the treatment group (P < 0.05). Further immunofluorescence staining confirmed that the expression of the Wnt signaling pathway protein (β-catenin) was upregulated in the NSC group (P < 0.05). ICV delivery of hNSCs promotes endogenous NSC proliferation and migration and ultimately enhances neuronal survival and neurological functional recovery. Wnt/β-catenin pathway may be involved in the initiation and maintenance of this enhancement.Graphical abstract.

Ligusticum chuanxiong exerts neuroprotection by promoting adult neurogenesis and inhibiting inflammation in the hippocampus of ME cerebral ischemia rats.

Cerebral ischemia, also known as stroke, can stimulate the proliferation and migration of endogenous neural stem cells (NSCS) in subventricular zone of the lateral ventricle and subgranularzone of the dentate gyrus in the adult hippocampus as a defense response to damage. However, the proliferation of endogenous NSCS is insufficient for central nervous system repair. Neurogenesis and anti-neuroinflammation are two important aspects for neuroprotection. Rhizome Ligusticum chuanxiong (LC), the dried rhizomes of Ligusticum striatum DC., has been widely used to treat stroke for over hundreds of years in Traditional Chinese Medicine. of the study: Previous reports on pharmacological mechanism of LC mainly focus on the cerebral blood flow and thrombolysis. We aim to explore whether LC provides neuroprotective effect by increasing neurogenesis and inhibiting the IL-1β, TNF-α and expressions of glial fibrillary acidic protein. LC extract was delivered to microsphere-embolized (ME) cerebral ischemia Wister rats to examine its neuroprotection. Body weight, neurological scores, hematoxylin-eosin staining (HE), TUNEL assay were conducted for neurological damage. Neurogenesis was evaluated by assessing the expression of Doublecortin (DCX) and neurogenic differentiation1 (NeuroD1) through immunofluorescence staining. Western blot performed to measure the protein levels of growth associated protein-43(GAP-43), glial fibrillary acidic protein (GFAP). IL-1β and TNF-α was detected by Elisa. LC alleviated pathomorphological change and apoptosis of neurons in the hippocampus caused by ME surgery. Furthermore, LC significantly increased the DCX in the DG of adult rat hippocampus at 14 days after surgery. A significant upregulation of GAP-43 compared to the ME after LC was administered. Besides, LC decreased pro-inflammatory cytokine (IL-1β, TNF-α) and protein level of GFAP. The finding suggested that LC had the ability to protect neurons by promoting the endogenous proliferation of neuroblast and production of neural differentiation factor in rats after ischemia injury. Meanwhile, LC can anti-neuroinflammation, which is important for the treatment of neuron injury. Accordingly, LC perhaps a promising medicine for neuron damage therapy after cerebral ischemia.

Effects and Mechanism of Action of Neonatal Versus Adult Astrocytes on Neural Stem Cell Proliferation After Traumatic Brain Injury.

Due to the limited capacity of brain tissue to self-regenerate after traumatic brain injury (TBI), the mobilization of endogenous neural stem cells (NSCs) is a popular research topic. In the clinic, the neurogenic abilities of adults versus neonates vary greatly, which is likely related to functional differences in NSCs. Recent studies have demonstrated that the molecules secreted from astrocytes play important roles in NSC fate determination. In this study, conditioned media (CM) derived from neonatal or adult rat astrocytes, which were unstimulated or stimulated by lipopolysaccharide (LPS), were prepared to treat NSCs. Our results revealed that neonatal rat astrocytes can significantly promote the proliferation of NSCs, compared with adult rat astrocytes, regardless of whether or not they were stimulated by LPS. Furthermore, we used mass spectrometry to detect the constituents of the CM from each group. We analyzed and screened for a protein, Tenascin-C (TNC), which was highly expressed in the neonatal group but poorly expressed in the adult group. We found that TNC can bind to the NSC surface epidermal growth factor receptor and promote proliferation through the PI3K-AKT pathway in vitro. Additionally, we confirmed in vivo that TNC can promote damage repair in a rat model of TBI, through enhancing the proliferation of endogenous NSCs. We believe that these findings provide a mechanistic understanding of why neonates show better neuroregenerative abilities than adults. This also provides a potential future therapeutic target, TNC, for injury repair after TBI. Stem Cells 2019;37:1344-1356.

Methylprednisolone inhibits the proliferation of endogenous neural stem cells in nonhuman primates with spinal cord injury

OBJECTIVE The aim of this work was to investigate the effects of methylprednisolone on the proliferation of endogenous neural stem cells (ENSCs) in nonhuman primates with spinal cord injury (SCI). METHODS A total of 14 healthy cynomolgus monkeys ( Macaca fascicularis) (4-5 years of age) were randomly divided into 3 groups: the control group (n = 6), SCI group (n = 6), and methylprednisolone therapy group (n = 2). Only laminectomy was performed in the control animals at T-10. SCI was induced in monkeys using Allen's weight-drop method (50 mm × 50 g) to injure the posterior portion of the spinal cord at T-10. In the methylprednisolone therapy group, monkeys were intravenously infused with methylprednisolone (30 mg/kg) immediately after SCI. All animals were intravenously infused with 5-bromo-2-deoxyuridine (BrdU) (50 mg/kg/day) for 3 days prior to study end point. The small intestine was dissected for immunohistochemical examination. After 3, 7, and 14 days, the spinal cord segments of the control and SCI groups were dissected to prepare frozen and paraffin sections. The proliferation of ENSCs was evaluated using BrdU and nestin immunofluorescence staining. RESULTS Histological examination showed that a larger number of mucosa epithelial cells in the small intestine of all groups were BrdU positive. Nestin-positive ependymal cells are increased around the central canal after SCI. After 3, 7, and 14 days of SCI, BrdU-positive ependymal cells in the SCI group were significantly increased compared with the control group, and the percentage of BrdU-positive cells in the left/right ventral horns and dorsal horn was significantly higher than that of the control group. Seven days after SCI, the percentages of both BrdU-positive ependymal cells around the central canal and BrdU- and nestin-double positive cells in the left/right ventral horns and dorsal horn were significantly lower in the methylprednisolone therapy group than in the SCI group. CONCLUSIONS While ENSCs proliferate significantly after SCI in nonhuman primates, methylprednisolone can inhibit the proliferation of ependymal cells after SCI.

Endogenous neural stem cells promotes Notch-1 expression after spinal cord injury in rats

Objective To explore the expressions and changes of endogenous neural stem cells (ENSCs) and Notch-1 after acute spinal cord injury in adult rats, and to explore its role in the nerve regeneration process. Methods The 30 Sprague Dawley (SD) female rats (3-6 months) (300-350 g) were divided into control groups (n=5) and experimental group (n=25) by digital random method. The control group only accepted lamina decompression, and the experimental group was the spinal cord injury group. Five rats were drawn when at 1 d, 3 d, 1 w, 2 w, and 4 w, then behavior, histology, immunohistochemistry and immunofluorescence method were used to detect the proliferation and expression of endogenous neural stem cells and Notch-1 protein. Results Behavioral observation showed the experimental group rats were disfunction. Histological observation showed nerve fiber structure turbulence, edema and denaturation in the experimental group. Immunohistochemistry staining showed the Notch-1 expression every experimental group. Notch-1 positive cell peaked at 3 days. Immunofluorescence test showed, in the experimental group damage to segment the area surrounding the BrdU positive staining cells was significantly higher than the control group. Using three-dimensional quantitative study method detected in 1w after spinal cord injury was the number of newborn cells mitosis, most about was about 75 times in the control group. Linear regression method was used to analyze the different time points after BrdU and Notch-1 protein expression positive area, the area of the results found that both into linear correlation. Conclusions The new born neurons after spinal cord injury in rats Notch-1 expression has a certain relevance. In addition, the expression of signal protein Notch-1, might be associated with early proliferation of ENSCs in rats. Key words: Spinal cord injuries; Receptor, Notch1; Stem cells; Nervous system/CY; Nerve regeneration

Osthole promotes endogenous neural stem cell proliferation and improved neurological function through Notch signaling pathway in mice acute mechanical brain injury

Mechanical brain injury (MBI) is a common neurotrosis disorder of the central nervous system (CNS), which has a higher mortality and disability. In the case of MBI, neurons death leads to loss of nerve function. To date, there was no satisfactory way to restore neural deficits caused by MBI. Endogenous neural stem cells (NSCs) can proliferate, differentiate and migrate to the lesions after brain injury, to replace and repair the damaged neural cells in the subventricular zone (SVZ), hippocampus and the regions of brain injury. In the present study, we first prepared a mouse model of cortical stab wound brain injury. Using the immunohistochemical and hematoxylin-eosin (H&E) staining method, we demonstrated that osthole (Ost), a natural coumarin derivative, was capable of promoting the proliferation of endogenous NSCs and improving neuronal restoration. Then, using the Morris water maze (MWM) test, we revealed that Ost significantly improved the learning and memory function in the MBI mice, increased the number of neurons in the regions of brain injury, hippocampus DG and CA3 regions. Additionally, we found that Ost up-regulated the expression of self-renewal genes Notch 1 and Hes 1. However, when Notch activity was blocked by the γ-secretase inhibitor DAPT, the expression of Notch 1 and Hes 1 mRNA was down-regulated, augmentation of NICD and Hes 1 protein was ameliorated, the proliferation-inducing effect of Ost was abolished. These results suggested that the effects of Ost were at least in part mediated by activation of Notch signaling pathway. Our findings support that Ost is a potential drug for treating MBI due to its neuronal restoration.

Neural Stem Cell-Based Regenerative Approaches for the Treatment of Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic, autoimmune, inflammatory, and demyelinating disorder of the central nervous system (CNS), which ultimately leads to axonal loss and permanent neurological disability. Current treatments for MS are largely comprised of medications that are either immunomodulatory or immunosuppressive and are aimed at reducing the frequency and intensity of relapses. Neural stem cells (NSCs) in the adult brain can differentiate into oligodendrocytes in a context-specific manner and are shown to be involved in the remyelination in these patients. NSCs may exert their beneficial effects not only through oligodendrocyte replacement but also by providing trophic support and immunomodulation, a phenomenon now known as "therapeutic plasticity." In this review, we first provided an update on the current knowledge regarding MS pathogenesis and the role of immune cells, microglia, and oligodendrocytes in MS disease progression. Next, we reviewed the current progress on research aimed toward stimulating endogenous NSC proliferation and differentiation to oligodendrocytes in vivo and in animal models of demyelination. In addition, we explored the neuroprotective and immunomodulatory effects of transplanted exogenous NSCs on T cell activation, microglial activation, and endogenous remyelination and their effects on the pathological process and prognosis in animal models of MS. Finally, we examined various protocols to generate genetically engineered NSCs as a potential therapy for MS. Overall, this review highlights the studies involving the immunomodulatory, neurotrophic, and regenerative effects of NSCs and novel methods aiming at stimulating the potential of NSCs for the treatment of MS.

Ellagic acid improves endogenous neural stem cells proliferation and neurorestoration through Wnt/β-catenin signaling in vivo and in vitro.

The aim of this study is to research the effects of the polyphenol ellagic acid (EA) on brain cells and to explore its mechanism of action, and to evaluate whether EA can be safely utilized by humans as a functional food or therapeutic agent. A photothrombosis-induced model of brain injury in rats was created, and EA was administered intragastrically to rats on 7 consecutive days post-venous ischemia. An oxygen-glucose deprivation and re-perfusion model was established in neural stem cells in order to research the effects on proliferation after 2 days of EA treatment in vitro. The administration of EA improved the rats' nerve-related abilities, remedied infarct volumes and morphological changes in the brain, and enhanced the content of nestin protein in the brain semidarkness zone. The proliferation of NSCs and the expression of β-catenin and Cyclin D1 genes were also increased in primary cultured NSCs. EA administration can improve brain injury outcomes and increase the proliferation of NSCs through the Wnt/β-catenin signaling pathway. The presented results represent new insights on the mechanisms of the brain cell protective activity of EA. Thus, EA may be used in functional foods or medicines to help treat nerve dysfunction, neurodegenerative disease and aging.

Effect of active factor on proliferation and differentiation of endogenous neural stem cells after traumatic brain injury in rats

Objective To investigate the effect of active factor on proliferation and differentiation of neural stem cells(NSCs)in the hippocampal subgranular zone after traumatic brain injury(TBI)in rats. Methods SD rats were divided into sham-injured group (only left dura mater exposed), active factor group (sham injury+ active factor therapy), TBI group (unilateral fluid percussion was used to generate severe TBI), and TBI+ active factor group (TBI+ active factor therapy) according to the random number table (n=10 in each group). Hippocampal homogenates or brain tissues were harvested at 7 d postinjury. Expressions of BrdU and NeuN in the hippocampal subgranular zone were detected by immunofluorescence staining, and five consecutive sections were used to count BrdU and NeuN positive cells. Level of nuclear factor (NF)-κB p65 in hippocampus was detected by Western blot. Results Number of BrdU and NeuN positive cells in TBI group were greatly higher than that in sham-injured group (P 0.05). NF-κBp65 presented over-expression in TBI group (0.81±0.09) while reversed in TBI+ active factor group (1.46±0.13), when compared to sham-injured group (P 0.05). Conclusion Active factor therapy can promote proliferation and neuronal differentiation of NSCs in the hippocampal subgranular zone after TBI in rats and the possible mechanism may relate to activation of the NSCs and inhibition of over-expression of NF-κBp65. Key words: Craniocerebral trauma; Neural stem cells; Active factor

Exogenous BDNF increases neurogenesis in the hippocampus in experimental Streptococcus pneumoniae meningitis

BackgroundDespite the effective use of antibiotics, occurrences of mortality and neurological sequelae following Streptococcus pneumoniae meningitis remain high. MethodsWe investigated the neurogenesis of endogenous neural stem cells (NSCs) after inoculation with exogenous brain-derived neurotrophic factor (BDNF) in the hippocampus dentate gyrus following experimental S. pneumoniae meningitis using a double-labeling immunofluorescence analysis with 5-bromo-2′-deoxyuridine (BrdU), Nestin, DCX and NeuN. ResultsOur results showed that 7days after inoculation, the number of BrdU & Nestin co-labeled cells increased in the hippocampus in meningitis rats compared with control rats (p<0.05). But the number of DCX-positive cells decreased in the dentate gyrus of infected rats treated with saline (p<0.05). However, these cell numbers returned to close to normal-control levels in infected rats treated with BDNF (p>0.05). After treatment with exogenous BDNF, the number of BrdU & Nestin co-labeled cells increased in the hippocampus in both the meningitis rats and normal control rats (p<0.05), but this increase was more significant in the former (p<0.05). We found that the percentage of BrdU & DCX/BrdU co-labeled cells increased in infected rats treated with BDNF both 7days and 14days after inoculation in a greater proportion compared to other groups (p<0.05). No significant differences were found in the percentage of BrdU & NeuN/BrdU 28days after inoculation among all of the groups (p>0.05). ConclusionOur findings suggest that S. pneumoniae meningitis activates the proliferation of endogenous NSCs, but impairs their early differentiation. Administration of exogenous BDNF might improve the neurogenesis of endogenous NSCs in the hippocampus and may provide a promising therapy after bacterial meningitis.