Mesenchymal stem cells protect against TBI-induced pyroptosis in vivo and in vitro through TSG-6.

BACKGROUND: Pyroptosis, especially microglial pyroptosis, may play an important role in central nervous system pathologies, including traumatic brain injury (TBI). Transplantation of mesenchymal stem cells (MSCs), such as human umbilical cord MSCs (hUMSCs), has been a focus of brain injury treatment. Recently, MSCs have been found to play a role in many diseases by regulating the pyroptosis pathway. However, the effect of MSC transplantation on pyroptosis following TBI remains unknown. Tumor necrosis factor α stimulated gene 6/protein (TSG-6), a potent anti-inflammatory factor expressed in many cell types including MSCs, plays an anti-inflammatory role in many diseases; however, the effect of TSG-6 secreted by MSCs on pyroptosis remains unclear. METHODS: Mice were subjected to controlled cortical impact injury in vivo. To assess the time course of pyroptosis after TBI, brains of TBI mice were collected at different time points. To study the effect of TSG-6 secreted by hUMSCs in regulating pyroptosis, normal hUMSCs, sh-TSG-6 hUMSCs, or different concentrations of rmTSG-6 were injected intracerebroventricularly into mice 4 h after TBI. Neurological deficits, double immunofluorescence staining, presence of inflammatory factors, cell apoptosis, and pyroptosis were assessed. In vitro, we investigated the anti-pyroptosis effects of hUMSCs and TSG-6 in a lipopolysaccharide/ATP-induced BV2 microglial pyroptosis model. RESULTS: In TBI mice, the co-localization of Iba-1 (marking microglia/macrophages) with NLRP3/Caspase-1 p20/GSDMD was distinctly observed at 48 h. In vivo, hUMSC transplantation or treatment with rmTSG-6 in TBI mice significantly improved neurological deficits, reduced inflammatory cytokine expression, and inhibited both NLRP3/Caspase-1 p20/GSDMD expression and microglial pyroptosis in the cerebral cortices of TBI mice. However, the therapeutic effect of hUMSCs on TBI mice was reduced by the inhibition of TSG-6 expression in hUMSCs. In vitro, lipopolysaccharide/ATP-induced BV2 microglial pyroptosis was inhibited by co-culture with hUMSCs or with rmTSG-6. However, the inhibitory effect of hUMSCs on BV2 microglial pyroptosis was significantly reduced by TSG-6-shRNA transfection. CONCLUSION: In TBI mice, microglial pyroptosis was observed. Both in vivo and in vitro, hUMSCs inhibited pyroptosis, particularly microglial pyroptosis, by regulating the NLRP3/Caspase-1/GSDMD signaling pathway via TSG-6. Video Abstract.

Circ-U2AF1 promotes human glioma via derepressing neuro-oncological ventral antigen 2 by sponging hsa-miR-7-5p.

The prognosis for human glioma, a malignant tumor of the central nervous system, is poor due to its rapid growth, genetic heterogeneity, and inadequate understanding of its underlying molecular mechanisms. Circular RNAs composed of exonic sequences, represent an understudied form of noncoding RNAs (ncRNAs) that was discovered more than a decade ago, function as microRNA sponges. We aimed to assess the relationship between circ-U2AF1 (CircRNA ID: hsa_circ_0061868) and hsa-mir-7-5p and examine their effects on proliferation, apoptosis, and the metastatic phenotype of glioma cells regulated by neuro-oncological ventral antigen 2 (NOVA2). We found that the expression levels of circ-U2AF1 and NOVA2 were upregulated, while hsa-miR-7-5p was downregulated in human glioma tissues and glioma cell lines. Our data and bioinformatic analysis indicated the association of these molecules with glioma grade, a positive correlation between circ-U2AF1 and NOVA2 expression levels and a negative correlation of hsa-miR-7-5p with both circ-U2AF1 and NOVA2, respectively. In addition, silencing of circ-U2AF1 expression resulted in increased hsa-miR-7-5p expression and decreased NOVA2 expression both in vitro and in vivo. Luciferase assay confirmed hsa-miR-7-5p as a direct target of circ-U2AF1 and NOVA2 as a direct target of hsa-miR-7-5p. Functionally, silencing of circ-U2AF1 inhibits glioma development by repressing NOVA2 via upregulating hsa-miR-7-5p both in vitro and in vivo. Thus, we assumed that circ-U2AF1 promotes glioma malignancy via derepressing NOVA2 by sponging hsa-miR-7-5p. Taken together, we suggest that circ-U2AF1 can be a prognostic biomarker and the circ-U2AF1/hsa-miR-7-5p/NOVA2 regulatory pathway may be a novel therapeutic target for treating gliomas.

LncRNA GAS5 regulates the proliferation, migration, invasion and apoptosis of brain glioma cells through targeting GSTM3 expression. The effect of LncRNA GAS5 on glioma cells.

INTRODUCTION: To investigate the effects of lncRNA GAS5 on the proliferation, migration, invasion and apoptosis of brain glioma cells. METHODS: The expression levels of lncRNA GAS5 and GSTM3 in normal glial cells (HEB) and glioma cells (U251 and U87) were detected by RT-qPCR and western blot, respectively. Glioma cells were transfected with ctrl vector, pcDNA-GAS5, siRNA ctrl (siNC) or GSTM3 siRNA and the effects of lncRNA GAS5 and GSTM3 on the proliferation, migration, invasion and apoptosis of glioma cells were detected by CCK-8 assay, transwell assay and Caspase 3/7 activity assay, respectively. RESULTS: The expression of lncRNA GAS5 was significantly decreased in glioma cell lines U251 and U87 compared with normal glial cells HEB (p < 0.01). In addition, overexpression of lncRNA GAS5 inhibited the proliferation, migration and invasion of U251 and U87 cells, and promoted cell apoptosis as demonstrated by the increased activity of Caspase 3/7. Furthermore, GSTM3 was predicted as a target gene of lncRNA GAS5 by bioinformatics analysis and its expression was increased in glioma cells compared with the normal cells as indicated by western blotting and RT-qPCR experimental results. Silencing of GSTM3 with GSTM3 siRNA decreased the proliferation, migration and invasion but increased the apoptosis of glioma cell lines U251 and U87, which was similar to that the effect lncRNA GAS5 over-expression. CONCLUSION: lncRNA GAS5 can effectively inhibit the proliferation, migration and invasion of glioma cells and promote cell apoptosis through targeting GSTM3 expression.

Anti-inflammatory Effect of Mesenchymal Stromal Cell Transplantation and Quercetin Treatment in a Rat Model of Experimental Cerebral Ischemia.

Here, we have investigated the synergistic effect of quercetin administration and transplantation of human umbilical cord mesenchymal stromal cells (HUMSCs) following middle cerebral artery occlusion in rat. Combining quercetin treatment with delayed transplantation of HUMSCs after local cerebral ischemia significantly (i) improved neurological functional recovery; (ii) reduced proinflammatory cytokines (interleukin(IL)-1ß and IL-6), increased anti-inflammatory cytokines (IL-4, IL-10, and transforming growth factor-ß1), and reduced ED-1 positive areas; (iii) inhibited cell apoptosis (caspase-3 expression); and (iv) improved the survival rate of HUMSCs in the injury site. Altogether, our results demonstrate that combined HUMSC transplantation and quercetin treatment is a potential strategy for reducing secondary damage and promoting functional recovery following cerebral ischemia.

Dual expression of hTERT and VEGF prolongs life span and enhances angiogenic ability of aged BMSCs.

Previous studies have confirmed the therapeutic effects of bone marrow stromal cells (BMSCs) transplantation on cerebral ischemia. However, the proliferative, differentiative, and homing capacity of BMSC from the elderly are significantly reduced, especially after several passages expansion in vitro. In this study, by introducing lentivirus-mediated hTERT and VEGF genes to modify human BMSCs from aged donors, we observed extended lifespan, promoted angiogenic capacity while less enhanced tumorigenicity of the genetically engineering BMSCs. These results therefore suggest that the modification of aged BMSCs by dual expression of hTERT and VEGF may be used for autologous cell replacement for ischemic cerebrovascular disease in elderly patients.

Comparison of the neural differentiation potential of human mesenchymal stem cells from amniotic fluid and adult bone marrow.

Human mesenchymal stem cells (MSCs) are considered a promising tool for cell-based therapies of nervous system diseases. Bone marrow (BM) has been the traditional source of MSCs (BM-MSCs). However, there are some limitations for their clinical use, such as the decline in cell number and differentiation potential with age. Recently, amniotic fluid (AF)-derived MSCs (AF-MSCs) have been shown to express embryonic and adult stem cell markers, and can differentiate into cells of all three germ layers. In this study, we isolated AF-MSCs from second-trimester AF by limiting dilution and compared their proliferative capacity, multipotency, neural differentiation ability, and secretion of neurotrophins to those of BM-MSCs. AF-MSCs showed a higher proliferative capacity and more rapidly formed and expanded neurospheres compared to those of BM-MSCs. Both immunocytochemical and quantitative real-time PCR analyses demonstrated that AF-MSCs showed higher expression of neural stemness markers than those of BM-MSCs following neural stem cell (NSC) differentiation. Furthermore, the levels of brain-derived growth factor and nerve growth factor secreted by AF-MSCs in the culture medium were higher than those of BM-MSCs. In addition, AF-MSCs maintained a normal karyotype in long-term cultures after NSC differentiation and were not tumorigenic in vivo. Our findings suggest that AF-MSCs are a promising and safe alternative to BM-MSCs for therapy of nervous system diseases.

Hydroxysafflor yellow a confers neuroprotection against acute traumatic brain injury by modulating neuronal autophagy to inhibit NLRP3 inflammasomes.

ETHNOPHARMACOLOGICAL RELEVANCE: Hydroxysafflor yellow A (HSYA) is the principal bioactive compound isolated from the plant Carthamus tinctorius L. and has been reported to exert neuroprotective effects against various neurological diseases, including traumatic brain injury (TBI). However, the specific molecular and cellular mechanisms underlying HSYA-mediated neuroprotection against TBI are unclear. AIM OF THE STUDY: This study explored the effects of HSYA on autophagy and the NLRP3 inflammasome in mice with TBI and the related mechanisms. MATERIALS AND METHODS: Mice were subjected to TBI and treated with or without HSYA. Neurological severity scoring, LDH assays and apoptosis detection were first performed to assess the effects of HSYA in mice with TBI. RNA-seq was then conducted to explore the mechanisms that contributed to HSYA-mediated neuroprotection. ELISA, western blotting, and immunofluorescence were performed to further investigate the mechanisms of neuroinflammation and autophagy. Moreover, 3-methyladenine (3-MA), an autophagy inhibitor, was applied to determine the connection between autophagy and the NLRP3 inflammasome. RESULTS: HSYA significantly decreased the neurological severity score, serum LDH levels and apoptosis in mice with TBI. A total of 921 differentially expressed genes were identified in the cortices of HSYA-treated mice with TBI and were significantly enriched in the inflammatory response and autophagy. Furthermore, HSYA treatment markedly reduced inflammatory cytokine levels and astrocyte activation. Importantly, HSYA suppressed neuronal NLRP3 inflammasome activation, as indicated by decreased levels of NLRP3, ASC and cleaved caspase-1 and a reduced NLRP3+ neuron number. It increased autophagy and ameliorated autophagic flux dysfunction, as evidenced by increased LC3 II/LC3 I levels and decreased P62 levels. The effects of HSYA on the NLRP3 inflammasome were abolished by 3-MA. Mechanistically, HSYA may enhance autophagy through AMPK/mTOR signalling. CONCLUSION: HSYA enhanced neuronal autophagy by triggering the AMPK/mTOR signalling pathway, leading to inhibition of the NLRP3 inflammasome to improve neurological recovery after TBI.

MCPIP-1 knockdown enhances endothelial colony-forming cell angiogenesis via the TFRC/AKT/mTOR signaling pathway in the ischemic penumbra of MCAO mice.

Cerebral ischemia is a serious disease characterized by brain tissue ischemia and hypoxic necrosis caused by the blockage of blood vessels within the central nervous system. Although stem cell therapy is a promising approach for treating ischemic stroke, the inflammatory, oxidative, and hypoxic environment generated by cerebral ischemia greatly reduces the survival and therapeutic effects of transplanted stem cells. Endothelial colony-forming cells (ECFCs) are a class of precursor cells with strong proliferative potential that can migrate and differentiate directly into mature vascular endothelial cells. Consequently, ECFCs can exert significant therapeutic and reparative effects in diseases associated with vascular injury. Monocyte chemoattractant protein-induced protein 1 (MCPIP-1) exerts multiple biological effects; however, no studies have yet reported its role in the angiogenic function of ECFCs. In this study, we performed Proteome Profiler™ Human Angiogenesis Antibody arrays and tandem mass tag protein profiling to investigate the effect of MCPIP-1 on ECFCs. We demonstrated that MCPIP-1 knockdown enhanced the proliferation, migration, and in vivo and in vitro angiogenic capacity of ECFCs by upregulating the transferrin receptor-activated AKT/m-TOR signaling pathway to promote cellular trophic factor secretion. Furthermore, we found that the lateral ventricular transplantation of ECFCs with lentiviral MCPIP-1 knockdown into mice with middle cerebral artery occlusion increased serum vacular endothelial growth factor(VEGF), angiopoietin-1, and HIF-1a levels, enhanced neovascularization and neurogenesis in the ischemic penumbra, reduced the size of cerebral infarcts, and promoted neurological recovery. Together, these findings suggest new avenues for enhancing the therapeutic efficacy of ECFCs.

[Long-term behavioral and ultrastructural alterations following hypoxic-ischemic brain damage in neonatal rats].

OBJECTIVE: To study long-term behavioral and ultrastructural alterations in a hypoxic-ischemic brain damage (HIBD) model of neonatal rats. METHODS: Sixty seven-day-old Sprague-Dawley rats were randomly subjected to unilateral carotid artery ligation followed by hypoxic exposure (HIBD group) or sham operation (n=30 each). A battery of behavioral tests, including Morris water maze test and sensorimotor tests, were performed at a postnatal age of 5 weeks. Nissl staining was used for counting neurons. Transmission electron microscopy was used for observing synapse structures and measuring the thickness of the postsynaptic density area and the length of the postsynaptic active area. The correlations of histological changes with the results of behavioral tests were evaluated. RESULTS: The HIBD group showed a significantly longer escape latency (P<0.05) and a lower frequency of original platform crossing (P<0.05) in the Morris water maze test compared with the sham operation group. The sensorimotor function test showed that the sensorimotor function in the HIBD group was worse than in the sham operation group. Nissl staining showed that the number of neurons in the HIBD group was significantly reduced (P<0.01) compared with the sham operation group. Transmission electron microscopy showed that synapses were significantly reduced in number, and that the thickness of the postsynaptic density area and the length of the postsynaptic active area were reduced in the HIBD group. The thickness of the postsynaptic density area was negatively correlated with escape latency in the Morris water maze test (r=-0.861, P<0.01), and also negatively correlated with the total score of sensorimotor function tests (r=-0.758, P<0.05) in the HIBD group. CONCLUSIONS: Hypoxia ischemia can lead to neuron loss and ultrastructure damage, resulting in long-term deficit of behavioral functions in neonatal rats.

The MicroRNA-106a/20b Strongly Enhances the Antitumour Immune Responses of Dendritic Cells Pulsed with Glioma Stem Cells by Targeting STAT3.

Background: Evaluate the effect of the miRNA-106a/20b on the efficacy of DCs pulsed with GSCs in activating GSC-specific T cell responses. Methods: We cultured GSCs and prepared GSC antigen lysates by apoptosis. Then, immature DCs were pulsed with GSC antigen lysates in vitro. STAT3 levels in DCs were assessed by Western blotting, and the expression of CD80, CD86, and MHC-II was tested by fluorescence-activated cell sorting. The production and secretion of the cytokines IL-6, IL-12, TNF-α, and IL-10 in DCs induced by GSCs were determined by enzyme-linked immunosorbent assay. Finally, the cytotoxic functions of T cells stimulated by GSC-DC fusion cells transfected with a miR-106a/20b mimic in vitro and the antitumour activity in vivo were detected. Results: We found that the levels of miR-106a/20b were downregulated, but the expression of STAT3 was significantly upregulated. Simultaneously, the inhibition of STAT3 in the fusion cells by STAT3-specific siRNA caused significant upregulation of the expression of CD80, CD86, and MHC-II, and the secretion of the cytokines IL-6 and IL-12 was substantially increased, IL-10 was markedly decreased. These findings revealed that STAT3 is an important regulator of DC maturation. Furthermore, the interactional binding sites between the 3'-untranslated region (3'-UTR) of STAT3 mRNA and miR-106a/20b were predicted by bioinformatics and verified by a dual-luciferase assay. Moreover, the reduction in STAT3 levels in GSC-DCs enhanced the generation of CD8+ T cells and reduced the generation of Foxp3+ regulatory T cells. Meanwhile, the secretion of the T cell cytokine IFN-γ was significantly increased. Further research showed that DCs after miR-106a/20b-mimics transfection could promote the inhibition of GSC proliferation by T cells in vitro and suppress tumour growth in vivo. Conclusions: This study indicted that the miR-106a/20b activation could be one of the important molecular mechanisms leading to enhance antitumour immune responses of GSC-mediated DCs, which downregulated the expression of STAT3 to alleviate its the inhibitory effect.

Indole-3-propionic acid alleviates ischemic brain injury in a mouse middle cerebral artery occlusion model.

Increasing evidence highlights the importance of gut microbiota and its metabolites as an environmental factor affecting ischemic stroke. However, the role of microbial indole metabolites in ischemic stroke remains largely unknown. Here, we evaluated the effects and the underlying mechanism of indole-3-propionic acid (IPA) in a mouse model of acute middle cerebral artery occlusion (MCAO) and the mechanisms underlying these effects. We collected blood samples and evaluated serum indole derivatives levels using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS) in 8-10-week-old male C57 mice undergoing MCAO or sham. Intragastric IPA administration (400 µg/20 g/d) was performed in mice with MCAO, and its effects and mechanisms were assessed. We found that the serum IPA levels were significantly lower in mice with MCAO than in sham-treated subjects. 16S rRNA gene sequencing revealed that IPA treatment ameliorated the MCAO-induced alterations of the gut microbiome structure, specifically reshaping the microbial community composition in mice with MCAO to resemble that in the mice from the control group, with an increase in the abundance of probiotics and a decrease in the abundance of harmful bacteria. IPA repaired the integrity of the intestinal barrier and regulated the activities of regulatory T cells (Tregs) and Th17 cells in the gut-associated lymphoid tissue. Intragastric IPA administration effectively alleviated neuroinflammation, neurological impairment and brain infarction. Of note, Tregs in the IPA treatment group inhibited A1 reactive astrogliosis in vitro. The beneficial effects of IPA are thus mediated by the gut microbiota, which could enable the development of prebiotics for microbiome-based treatments for ischemic stroke.

Expression of cytokines in rat brain with focal cerebral ischemia after grafting with bone marrow stromal cells and endothelial progenitor cells.

BACKGROUND AIMS: This study aimed to observe nine factors expressed in rat ischemic brain after transplantation of bone marrow stromal cells (BMSC) and/or endothelial progenitor cells (EPC). These factors were vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 (SDF-1), basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF-l), transforming growth factor-ß (TGF-ß), platelet-derived growth factor-BB (PDGF-BB), brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF). METHODS: Adult Wistar rats were divided randomly into four groups: a vehicle group, BMSC group, EPC group and BMSC combined with EPC group. The rats were subjected to middle cerebral artery occlusion (MCAO) then implanted intravenously with 3 × 10(6) BMSC, EPC, BMSC/EPC or phosphate-buffered saline (PBS) 24 h after MCAO. Neurologic functional deficits were measured on days 1, 7, 14, 28 after transplantation. On day 7 after transplantation, quantitative reverse transcription (qRT)-polymerase chain reaction (PCR) and Western blot were employed to detect the expression of VEGF, SDF-1, bFGF, IGF-l, TGF-ß, PDGF-BB, BDNF, GDNF and NGF. RESULTS: The neurologic evaluation found that the neurologic severity scores were no different between the four groups on day 1, and the scores of rats in the BMSC/EPC group were significantly lower than those of rats in the other groups on days 7, 14 and 28 after transplantation. The expressions of bFGF, VEGF and BNDF were significantly higher in the BMSC/EPC group compared with the other groups. CONCLUSIONS: The intravenous transplantation of BMSC combined with EPC could promote the functional rehabilitation of rats with focal cerebral ischemia, and the mechanism may be related to the enhanced expression of factors.

A study of the distribution and density of the VEGFR-2 receptor on glioma microvascular endothelial cell membranes.

The purpose of the study was to examine the nanoscale distribution and density of the VEGFR-2 membrane receptor on the endothelial cell surface of glioma microvasculature. Immunofluorescence and atomic force microscopy combined with immunogold labeling techniques were used to characterize and determine the position of the glioma microvasculature endothelial cell surface receptor VEGFR-2. We aimed to indirectly detect the distribution of VEGFR-2 on the cell membrane at the nanoscale level and to analyze VEGFR-2 quantitatively. Immunofluorescence imaging showed a large amount of VEGFR-2 scattered across the endothelial cell surface; atomic force microscopy imaging also showed two globular structures of different sizes scattered across the endothelial cell surface. The difference between the average diameter of the small globular structure outside the cell surface (43.67 ± 5.02 nm) and that of IgG (44.61 ± 3.19 nm) was not statistically significant (P > 0.05). The three-dimensional morphologies of the small globular structure outside the cell surface and IgG were similar. The difference between the average diameter of the large globular structure outside the cell surface (74.19 ± 9.10 nm) and that of IgG-SpA-CG (74.54 ± 15.93 nm) was also not statistically significant (P > 0.05). The three-dimensional morphologies of this large globular structure outside the cell surface and IgG-SpA-CG were similar. The total density of these two globular structures within the unit area was 92 ± 19 particles µm(2). No globular structures were seen on the cell surface in the control group. The large globular structure on the surface of glioma microvascular endothelial cells was categorized as a VEGFR-2-IgG-SpA-CG immune complex, whereas the small globular structure was categorized as a VEGFR-2-IgG immune complex. The positions of the globular structures were the same as the positions of the VEGFR-2 molecules. A large amount of VEGFR-2 was scattered across glioma microvascular endothelial cell surfaces; the receptor density was about 92 per square micron.

Comparison of transdifferentiated and untransdifferentiated human umbilical mesenchymal stem cells in rats after traumatic brain injury.

Transdifferentiated and untransdifferentiated mesenchymal stem cells (MSCs) have shown therapeutic benefits in central nervous system (CNS) injury. However, it is unclear which would be more appropriate for transplantation. To address this question, we transplanted untransdifferentiated human umbilical mesenchymal stem cells (HUMSCs) and transdifferentiated HUMSCs (HUMSC-derived neurospheres, HUMSC-NSs) into a rat model of traumatic brain injury. Cognitive function, cell survival and differentiation, brain tissue morphology and neurotrophin expression were compared between groups. Significant improvements in cognitive function and brain tissue morphology were seen in the HUMSCs group compared with HUMSC-NSs group, which was accompanied by increased neurotrophin expression. Moreover, only few grafted cells survived in both the HUMSCs and HUMSC-NSs groups, with very few of the cells differentiating into neural-like cells. These findings indicate that HUMSCs are more appropriate for transplantation and their therapeutic benefits may be associated with neuroprotection rather than cell replacement.

Human Wharton's jelly cells can be induced to differentiate into growth factor-secreting oligodendrocyte progenitor-like cells.

Human Wharton's jelly-derived mesenchymal stromal cells (hWJ-MSCs) are capable of differentiating into neural and astroglia-like cell types. However, a reliable means of inducing the selective differentiation of hWJ-MSCs into oligodendrocyte progenitor cells (OPCs) in vitro has not yet been established. In this study, the OPC-like differentiation of hWJ-MSCs was characterized using and immunoblotting. The hWJ-MSC-derived OPC-like cells were able to secrete nerve growth factors and promote neurite outgrowth in vitro. These results show that hWJ-MSCs can be induced to differentiate into cells with the morphologic, phenotypic and functional characteristics of OPC-like cells.

Human umbilical cord mesenchymal stem cell-derived exosomal miR-146a-5p reduces microglial-mediated neuroinflammation via suppression of the IRAK1/TRAF6 signaling pathway after ischemic stroke.

To investigate the therapeutic mechanism of action of transplanted stem cells and develop exosome-based nanotherapeutics for ischemic stroke, we assessed the effect of exosomes (Exos) produced by human umbilical cord mesenchymal stem cells (hUMSCs) on microglia-mediated neuroinflammation after ischemic stroke. Our results found that injected hUMSC-Exos were able to access the site of ischemic damage and could be internalized by cells both in vivo and in vitro. In vitro, treatment with hUMSC-Exos attenuated microglia-mediated inflammation after oxygen-glucose deprivation (OGD). In vivo results demonstrated that treatment with hUMSC-Exos significantly reduced infarct volume, attenuated behavioral deficits, and ameliorated microglia activation, as measured three days post-transient brain ischemia. Furthermore, miR-146a-5p knockdown (miR-146a-5p k/d Exos) partially reversed the neuroprotective effect of hUMSC-Exos. Our mechanistic study demonstrated that miR-146a-5p in hUMSC-Exos reduces microglial-mediated neuroinflammatory response through IRAK1/TRAF6 pathway. We conclude that miR-146a-5p derived from hUMSC-Exos can attenuate microglia-mediated neuroinflammation and consequent neural deficits following ischemic stroke. These results elucidate a potential therapeutic mechanism of action of mesenchymal stem cells and provide evidence that hUMSC-Exos represent a potential cell-free therapeutic option for ischemic stroke.

Investigation of a plasmid containing a novel immunotoxin VEGF165-PE38 gene for antiangiogenic therapy in a malignant glioma model.

Inhibition of tumor neovascularization has profound effects on the growth of solid tumors. Our previous studies have shown the effect of VEGF165-PE38 recombinant immunotoxin on proliferation and apoptosis in human umbilical vein endothelial cells in vitro. In this study, we explored the direct inhibition of angiogenesis in chick chorioallantoic membrane and antiangiogenic therapy in a malignant glioma model. HEK293 cells were transfected with the pVEGF165PE38-IRES2-EGFP plasmid. ELISA was used to confirm the expression of VEGF165-PE38 in the transfected cells. These cells released 1396 + or - 131.9 pg VEGF165-PE38/1x10(4) cells/48 h into the culture medium and the supernatant was capable of inhibiting the growth of capillary-like structures in chick chorioallantoic membrane assay. In a murine malignant glioma model, plasmid was directly administered via multiple local intratumoral delivery. After day 16 the tumor volume in mice treated with pVEGF165PE38-IRES2-EGFP was significantly lower than that in mice in the control groups. Immunohistochemistry studies showed that the treated group had decreased expression of CD31. Quantitative analysis of microvessel density in the treated group was 1.99 + or - 0.69/0.74 mm(2), and was significantly lower than that in the control groups (9.33 + or - 1.99/0.74 mm(2), 8.09 + or - 1.39/0.74 mm(2) and 8.49 + or - 1.69/0.74 mm(2)). Immunohistochemistry analysis indicated that immunotoxin VEGF165-PE38 was distributed in the treated group in malignant glioma tissue. Our findings provide evidence that the in vivo production of VEGF165-PE38 through gene therapy using a eukaryotic expression plasmid had potential antiangiogenic activity in malignant glioma in vivo.

Therapeutic DNA vaccination as a repair strategy following spinal cord injury.

Myelin-derived proteins, such as tenascin-R (TN-R), myelin associate glycoprotein (MAG), oligodendrocyte-myelin glycoprotein (OMgp), and Nogo-A, inhibit the central nervous system regeneration. In this study, the DNA vaccine encoding for oligodendrocyte and myelin-related antigens was employed to attenuate the axonal growth inhibitory properties of myelin in the setting of spinal cord injury. Using a rat spinal cord dorsal hemisection model, the vaccine directed against the inhibitory epitopes of Nogo-A, MAG, OMgp, and TN-R was administered intramuscularly once a week following spinal cord injury, supplemented with local application of specific anti-sera against the four antigens. Anterograde labeling of dorsal column fibers showed active axonal regeneration through the lesion site at the eighth week following the treatment in experimental group but not in control groups. Light microscopic and ultrastructural analysis revealed that vaccination with these myelin-related antigens did not lead to demyelinating disease. OMgp and TN-R levels were down-regulated at the lesion site together with a parallel increase in growth-associated protein 43 levels in the treatment groups. This study reveals the effective approach of a DNA vaccine strategy by attaining the special antibody to direct neutralization of the myelin inhibitors during spinal cord injury.

Human umbilical vein-derived dopaminergic-like cell transplantation with nerve growth factor ameliorates motor dysfunction in a rat model of Parkinson's disease.

Mesenchymal stem cells are capable of differentiating into dopaminergic-like cells, but currently no report has been available to describe the induction of human umbilical vein mesenchymal stem cells (HUVMSCs) into dopaminergic-like cells. In this study, we induced HUVMSCs in vitro into neurospheres constituted by neural stem-like cells, and further into cells bearing strong morphological, phenotypic and functional resemblances with dopaminergic-like cells. These HUVMSC-derived dopaminergic-like cells, after grafting into the brain of a rat model of Parkinson's disease (PD), showed a partial therapeutic effect in terms of the behavioral improvement. Nerve growth factor was reported to improve the local microenvironment of the grafted cells, and we therefore further tested the effect of dopaminergic-like cell grafting combined with nerve growth factor (NGF) administration at the site of cell transplantation. The results showed that NGF administration significantly promoted the survival of the grafted cells in the host brain and enhanced the content of dopaminergic in the local brain tissue. Behavioral test demonstrated a significant improvement of the motor function of the PD rats after dopaminergic-like cell grafting with NGF administration as compared with that of rats receiving the cell grafting only. These results suggest that transplantation of the dopaminergic-like cells combined with NGF administration may represent a new strategy of stem cell therapy for PD.

Passive immunization with LINGO-1 polyclonal antiserum afforded neuroprotection and promoted functional recovery in a rat model of spinal cord injury.

LINGO-1 (leucine-rich repeat and Ig domain-containing, Nogo receptor-interacting protein) is an important component of the NgR receptor complex involved in RhoA activation and axon regeneration. The authors report on passive immunization with LINGO-1 polyclonal antiserum, a therapeutic approach to overcome NgR-mediated growth inhibition after spinal cord injury (SCI). The intrathecally administered high-titer rabbit-derived antiserum can be detected around the injury site within a wide time window; it blocks LINGO-1 in vivo with high molecular specificity. In this animal model, passive immunization with LINGO-1 antiserum significantly decreased RhoA activation and increased neuronal survival. Adult rats immunized in this manner show recovery of certain hindlimb motor functions after dorsal hemisection of the spinal cord. Thus, passive immunotherapy with LINGO-1 polyclonal antiserum may represent a promising repair strategy following acute SCI.