Dekang Nie

BDNF blended chitosan scaffolds for human umbilical cord MSC transplants in traumatic brain injury therapy.

This study tested the cytotoxicity of a BDNF blended chitosan scaffold with human umbilical cord mesenchymal stem cells (hUC-MSCs), and the in vitro effect of BDNF blended chitosan scaffolds on neural stem cell differentiation with the aim of contributing alternative methods in tissue engineering for the treatment of traumatic brain injury (TBI). The chitosan scaffold based on immobilization of BDNF by genipin (GP) as a crosslinking agent referred to hereafter as a CGB scaffold was prepared by freezing-drying technique. hUC-MSCs were co-cultured with the CGB scaffold. Fluorescent nuclear staining (Hoechst 33342) was employed to determine the attachment of the hUC-MSCs to CGB scaffolds on the 1st, 3rd, 7th and 10th day of co-culture. The viability of hUC-MSCs adhered to the CGB scaffold was determined by digesting with 0.25% trypsin and evaluating with the cell counting kit-8 (CCK-8). Prior to this, the diameter and porosity of CGB scaffolds were measured. The amount of BDNF released from CGB over a 30 day period was determined by ELISA. Finally, we investigated whether the released BDNF can induce NSC to differentiate into neurons. There were no significant differences in diameter and porosity of individual CGB scaffolds (P > 0.05). There were on average more cells on the CGB scaffold on the first day than on any other day sampled (P < 0.05). The CGB scaffolds released BDNF in a uniform profile, whereas the CB scaffolds only released BDNF during the first 3 days. BDNF released from CGB scaffold promoted neuronal differentiation of NSCs and led to significant differences in differentiation rate and average neuron perimeter compared with the control group. The results of this study demonstrate that CGB scaffolds are biocompatible with hUC-MSCs and that granular CGB scaffolds covered with hUC-MSCs are expected to generate new advances for future treatment of traumatic brain injury.

Lycium barbarum polysaccharides prevent memory and neurogenesis impairments in scopolamine-treated rats.

Lycium barbarum is used both as a food additive and as a medicinal herb in many countries, and L. barbarum polysaccharides (LBPs), a major cell component, are reported to have a wide range of beneficial effects including neuroprotection, anti-aging and anticancer properties, and immune modulation. The effects of LBPs on neuronal function, neurogenesis, and drug-induced learning and memory deficits have not been assessed. We report the therapeutic effects of LBPs on learning and memory and neurogenesis in scopolamine (SCO)-treated rats. LBPs were administered via gastric perfusion for 2 weeks before the onset of subcutaneous SCO treatment for a further 4 weeks. As expected, SCO impaired performance in novel object and object location recognition tasks, and Morris water maze. However, dual SCO- and LBP-treated rats spent significantly more time exploring the novel object or location in the recognition tasks and had significant shorter escape latency in the water maze. SCO administration led to a decrease in Ki67- or DCX-immunoreactive cells in the dentate gyrus and damage of dendritic development of the new neurons; LBP prevented these SCO-induced reductions in cell proliferation and neuroblast differentiation. LBP also protected SCO-induced loss of neuronal processes in DCX-immunoreactive neurons. Biochemical investigation indicated that LBP decreased the SCO-induced oxidative stress in hippocampus and reversed the ratio Bax/Bcl-2 that exhibited increase after SCO treatment. However, decrease of BDNF and increase of AChE induced by SCO showed no response to LBP administration. These results suggest that LBPs can prevent SCO-induced cognitive and memory deficits and reductions in cell proliferation and neuroblast differentiation. Suppression of oxidative stress and apoptosis may be involved in the above effects of LBPs that may be a promising candidate to restore memory functions and neurogenesis.

An IDH1 mutation inhibits growth of glioma cells via GSH depletion and ROS generation

The isocitrate dehydrogenase 1 (IDH1) gene mutation occurs frequently in glioma. While some studies have demonstrated that IDH1 mutations are associated with prolonged survival, the mechanism remains unclear. In this study, we found that growth was significantly inhibited in glioma cells overexpressing the mutated IDH1 gene. Furthermore, these cells were characterized by decreased intracellular NADPH levels accompanied by glutathione (GSH) depletion and reactive oxygen species (ROS) generation. Moreover, the increased apoptosis and the decreased proliferation were found in the glioma cells overexpressing the mutant IDH1 gene. Accordingly, our study demonstrates that using H2O2-regulated mutant IDH1 glioma cells could obviously increase the inhibition of cell growth; nevertheless, GSH had the opposite result. Our study provides direct evidence that mutation of IDH1 profoundly inhibits the growth of glioma cells, and we speculate that this is the major factor behind its association with prolonged survival in glioma. Finally, our study indicates that depletion of GSH and generation of ROS are the primary cellular events associated with this mutation.

Therapeutic Effect of Human Umbilical Cord Mesenchymal Stem Cells on Neonatal Rat Hypoxic-Ischemic Encephalopathy

The therapeutic potential of umbilical cord blood mesenchymal stem cells has been studied in several diseases. However, the possibility that human umbilical cord Whartons jelly‐derived mesenchymal stem cells (hUCMSCs) can be used to treat neonatal hypoxic–ischemic encephalopathy (HIE) has not yet been investigated. This study focuses on the potential therapeutic effect of hUCMSC transplantation in a rat model of HIE. Dermal fibroblasts served as cell controls. HIE was induced in neonatal rats aged 7 days. hUCMSCs labeled with Dil were then transplanted into the models 24 hr or 72 hr post‐HIE through the peritoneal cavity or the jugular vein. Behavioral testing revealed that hUCMSC transplantation but not the dermal fibroblast improved significantly the locomotor function vs. vehicle controls. Animals receiving cell grafts 24 hr after surgery showed a more significant improvement than at 72 hr. More hUCMSCs homed to the ischemic frontal cortex following intravenous administration than after intraperitoneal injection. Differentiation of engrafted cells into neurons was observed in and around the infarct region. Gliosis in ischemic regions was significantly reduced after hUCMSC transplantation. Administration of ganglioside (GM1) enhanced the behavioral recovery on the base of hUCMSC treatment. These results demonstrate that intravenous transplantation of hUCMSCs at an early stage after HIE can improve the behavior of hypoxic–ischemic rats and decrease gliosis. Ganglioside treatment further enhanced the recovery of neurological function following hUCMSC transplantation.

PAX3 is overexpressed in human glioblastomas and critically regulates the tumorigenicity of glioma cells.

Paired box 3 (PAX3) is overexpressed in glioma tissues compared to normal brain tissues, however, the pathogenic role of PAX3 in human glioma cells remains to be elucidated. In this study, we selected the human glioma cell lines U251, U87, SHG-44, and the normal human astrocytes, 1800, which have differential PAX3 expression depending upon the person. SiRNA targeting PAX3 and PAX3 overexpression vectors were transfected into U87 and SHG-44 glioma cell lines, and cell proliferation, invasion, apoptosis, and differentiation were examined by CCK-8 assays, transwell chamber assays, tunnel staining, Annexin V/PI analysis, and Western blotting, respectively. In addition, we used subcutaneous tumor models to study the effect of PAX3 on the growth of glioma cells in vivo. We found that PAX3 was upregulated in the three glioma cell lines. PAX3 knockdown inhibited cell proliferation and invasion, and induced apoptosis in the U87MG glioblastoma cell line, whereas PAX3 upregulation promoted proliferation, inhibited apoptosis, and increased invasion in the SHG-44 glioma cell line. Moreover, we found that targeting PAX3 expression in glioma cell lines together with chemotherapeutic treatment could increase glioma cell susceptibility to the drug. In subcutaneous tumor models in nude mice using glioma cell lines U-87MG and SHG-44, inhibition of PAX3 expression in glioblastoma U-87MG cells suppressed tumorigenicity, and upregulation of PAX3 expression in glioma SHG-44 cells promoted tumor formation in vivo. These results indicate that PAX3 in glioma is essential for gliomagenesis; thus, targeting PAX3 or its downstream targets may lead to novel therapies for this disease.

Clinical Significance and Prognostic Value of PAX3 Expression in Human Glioma

The paired box 3 (PAX3), a crucial transcription factor, is normally expressed during embryonic development and is absent in normal adult human tissues. Deregulated expression of PAX3 has been observed in tumors like rhabdomyosarcoma and melanomas. To assess deregulated PAX3 expression in patients with gliomas, these samples from 57 glioma patients (13 grade I, 16 grade II, 14 grade III, and 14 grade IV tumors) and 10 normal brain specimens acquired from 10 patients undergoing surgery for epilepsy as control were obtained. PAX3 expression was measured by RT-PCR, Western blot, and immunohistochemistry. Survival analyses were performed using the Kaplan–Meier method. Association between PAX3 expression, clinicopathological characteristics, and patients’ survival were analyzed by using SPSS 17.0. We found that the expression of PAX3 was upregulated in high-grade glioma tissues compared with that in low-grade and normal brain tissues, and increased with ascending tumor World Health Organization (WHO) grades (P = 0.001). The increased PAX3 expression in gliomas was significantly associated with higher WHO grade (P = 0.021) and poorer disease-specific survival of patients (P = 0.001). Our results suggested that PAX3 might be an intrinsic regulator of progression in glioma cells and it might serve as a prognostic factor for this dismal disease.

The migration and differentiation of hUC-MSCs CXCR4/GFP encapsulated in BDNF/chitosan scaffolds for brain tissue engineering

We previously developed a biomaterial scaffold that could effectively provide seed cells to a lesion cavity resulting from traumatic brain injury. However, we subsequently found that few transplanted human umbilical cord mesenchymal stem cells (hUC-MSCs) are able to migrate from the scaffold to the lesion boundary. Stromal derived-cell factor-1α and its receptor chemokine (C-X-C motif) receptor (CXCR)4 are chemotactic factors that control cell migration and stem cell recruitment to target areas. Given the low expression level of CXCR4 on the hUC-MSC membrane, lentiviral vectors were used to generate hUC-MSCs stably expressing CXCR4 fused to green fluorescent protein (GFP) (hUC-MSCs(CXCR4/GFP)). We constructed a scaffold in which recombinant human brain-derived neurotrophic factor (BDNF) was linked to chitosan scaffolds with the crosslinking agent genipin (CGB scaffold). The scaffold containing hUC-MSCs(CXCR4/GFP) was transplanted into the lesion cavity of a rat brain, providing exogenous hUC-MSCs to both lesion boundary and cavity. These results demonstrate a novel strategy for inducing tissue regeneration after traumatic brain injury.

Teaching NeuroImages: Giant neurocysticercosis with unusual imaging manifestations: [RETRACTED]

A 6-year-old girl presented with a 3-month history of progressive left-eye strabismus and vision loss. MRI scan of the brain showed a single hypointense lesion in the left cerebral hemisphere with no perilesional edema or contrast enhancement (figure 1, A–C). At surgery, the lesion was shown to be a single large parasitic cyst measuring approximately 7.0 × 6.5 × 6.0 cm (figure 2, A–C). The patient underwent a complete resection and then was given antihelminthic therapy. This resulted in an uneventful recovery. Pathology confirmed a diagnosis of cysticercus cyst with scolex. This imaging feature of giant neurocysticercosis is very unusual.1 In the event of neurologic dysfunction or elevated intracranial pressure, emergent operative intervention should precede the administration of antihelminthic medications as the latter may weaken the cyst membrane and complicate resection. Gross total resection has advantages compared with nonsurgical treatment with antihelminthics.2

Phosphorylation of Mitogen- and Stress-Activated Protein Kinase-1 in Astrocytic Inflammation: A Possible Role in Inhibiting Production of Inflammatory Cytokines

Purpose It is generally accepted that inflammation has a role in the progression of many central nervous system (CNS) diseases, although the mechanisms through which this occurs remain unclear. Among mitogen-activated protein kinase (MAPK) targets, mitogen- and stress-activated protein kinase (MSK1) has been thought to be involved in the pathology of inflammatory gene expression. In this study, the roles of MSK1 activation in neuroinflammation were investigated. Methods The bacterial lipopolysaccharide (LPS)-induced brain injury model was performed on Sprague-Dawley rats. The dynamic expression changes and the cellular location of p-MSK1 in the brain cortex were detected by Western blot and immunofluorescence staining. The synthesis of inflammatory cytokines in astrocytes was detected by enzyme-linked immunosorbent assay (ELISA). Results Phosphorylated MSK1 (p-MSK1 Thr-581) was induced significantly after intracerebral injection of LPS into the lateral ventricles of the rat brain. Specific upregulation of p-MSK1 in astrocytes was also observed in inflamed cerebral cortex. At 1 day after LPS stimulation, iNOS, TNFα expression, and the astrocyte marker glial fibrillary acidic protein (GFAP) were increased significantly. Also, in vitro studies indicated that the upregulation of p-MSK1 (Thr-581) may be involved in the subsequent astrocyte inflammatory process, following LPS challenge. Using an enzyme-linked immunosorbent assay (ELISA), it was confirmed that treatment with LPS in primary astrocytes stimulated the synthesis of inflammatory cytokines, through MAPKs signaling pathways. In cultured primary astrocytes, both knock-down of total MSK1 by small interfering RNAs (siRNA) or specific mutation of Thr-581 resulted in higher production of certain cytokines, such as TNFα and IL-6. Conclusions Collectively, these results suggest that MSK1 phosphorylation is associated with the regulation of LPS-induced brain injury and possibly acts as a negative regulator of inflammation.

MiR-29b inhibits the growth of glioma via MYCN dependent way

MiR-29b is widely involved in diverse cancers. We plan to study its role in glioma. The expression of miR-29b was detected by real-time polymerase chain reaction (PCR) and we found the expression of miR-29b was decreased in glioma. Cell proliferation was evaluated by cell counting kit (CCK8) and 5-Ethynyl-2′- deoxyuridine (EdU) and cell apoptosis was assayed with flow cytometry assay (FCA), which indicated miR-29b can inhibit the proliferation and promote the apoptosis of glioma cells. The target of miR-29b was predicted using miRanda, TargetScan and PicTar sofeware and we also found MYCN was a direct target of miR-29b in glioma cells and miR-29b inhibited the proliferation of glioma cells via MYCN dependent way. Subcutaneous xenotransplantation model was designed to investigate the affection of miR-29b on glioma growth. The effectiveness of miR-29b for glioma prediction was also performed and we determined miR-29b can stably exist and may act as a biomarker for the diagnosis of glioma. As a conclusion, miR-29b inhibits the growth of glioma via MYCN dependent way and can be a biomarker for the diagnosis of glioma.