The Effect of Differentiation of Human Dental Pulp Stem Cells to Glial Cells on the Sensory Nerves of the Dental Pulp.

Regeneration of sensory nerves is challenging in dental pulp regeneration. Schwann cells (SCs) are essential glial cells conducive to regenerating sensory nerve, but their source is scarce. The aim of the protocol was to investigate the regenerative potential of Schwann-like cells derived from dental pulp stem cells (SC-DPSCs) for sensory nerve regrowth. SC-DPSCs were generated from dental pulp stem cells using a three-step protocol. The expression of key markers, including myelin basic protein, S-100, and p75 neurotrophin receptor, was analyzed. Primary trigeminal neurons were cultured, and the expression of neurofilament 200, ß-tubulin III, and microtubule-associated protein 2 was assessed. Simultaneous culture experiments were conducted to evaluate trigeminal neuron growth in the presence of SC-DPSCs. In addition, mRNA sequencing was performed to identify key genes involved in the differentiation process, highlighting prostaglandin-endoperoxide synthase 2 (PTGS2) as a potential candidate. The results demonstrated that SC-DPSCs expressed characteristic SCs markers and facilitated axonal growth in rat trigeminal nerves. Differentiated SC-DPSCs secreted elevated levels of nerve growth factors, including brain-derived neurotrophic factor and neurotrophin-3, promoting the growth of trigeminal nerve axons. These findings suggest the regenerative potential of SC-DPSCs in dentin-dental pulp complex; PTGS2 is considered a crucial gene in this differentiation process.

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.

High Performance Low-Temperature Lithium Metal Batteries Enabled by Tailored Electrolyte Solvation Structure.

The electrochemical performances of lithium metal batteries are determined by the kinetics of interfacial de-solvation and ion transport, especially at low-temperature environments. Here, a novel electrolyte that easily de-solvated and conducive to interfacial film formation is designed for low-temperature lithium metal batteries. A fluorinated carboxylic ester, diethyl fluoromalonate (DEFM), and a fluorinated carbonate, fluoroethylene carbonate (FEC) are used as solvents, while high concentrated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is served as the solute. Through tailoring the electrolyte formulation, the lithium ions in the high concentrated fluorinated carboxylic ester electrolyte are mainly combined with anions, which weakens the bonding strength of lithium ions and solvent molecules in the solvation structure, beneficial to the de-solvation process at low temperature. The fluorinated carboxylic ester (FCE) electrolyte enables the LiFePO4 (LFP) | Li half-cell achieves a high capacity of 91.9 mAh g-1 at -30 °C, with high F content in the interface. With optimized de-solvation kinetics, the LFP | Li full cell remains over 100 mAh g-1 at 0 °C after cycling 100 cycles. Building new solvents with outstanding low-temperature properties and weaker solvation to match with Li metal anode, this work brings new possibilities of realizing high energy density and low temperature energy storage batteries.

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.

[Effects of let-7a on proliferation, osteogenic differentiation and apoptosis of human dental pulp stem cells].

PURPOSE: To study the effect and possible mechanism of let-7a on proliferation, differentiation and apoptosis of human dental pulp stem cell (hDPSCs). METHODS: The cells were divided into four groups: overexpression control (let-7a control/let-7a agomir control), overexpression let-7a (let-7a mimics/let-7a agomir), knockdown let-7a control (let-7a inhibitor control) and knockdown let-7a (let-7a inhibitor). Cell counting kit-8 assay(CCK-8) was used to detect the proliferation of cells at 24 hours, 48 hours and 72 hours after transfection. Calcified nodules were detected by Alizarin red staining. The protein expression of alkaline phosphatase (ALP), osteopontin (OPN), 4E-binding protein 1 (4EBP1), p-4EBP1, mammalian target of rapamycin (mTOR) and p-mTOR were detected by Western blot. Annexin V-APC/7-AAD cell apoptosis detection kit was used to detect the level of apoptosis after transfection. Statistical analysis was performed using GraphPad Prism 5.0 software. RESULTS: Let-7a inhibited proliferation of hDPSCs and promoted odontoblast differentiation and apoptosis. Let-7a down-regulated the expression of 4EBP1, p-4EBP1, mTOR and p-mTOR. CONCLUSIONS: Let-7a may inhibit proliferation of hDPSCs and promote their differentiation and apoptosis by inhibiting mTOR-4EBP1 molecular pathway.

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.

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.

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.

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.

Meta-Analysis of the Safety and Efficacy of Stem Cell Therapies for Ischemic Stroke in Preclinical and Clinical Studies.

Recent studies have indicated that stem cell transplantation may be effective in the treatment of ischemic stroke. Therefore, we performed a meta-analysis to evaluate the safety and efficacy of stem cell therapy for ischemic stroke in preclinical and clinical studies. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched the PubMed, Cochrane Library, Embase, Web of science, and Ovid databases from inception through May 2018. A total of 11 preclinical studies-18 independent interventions were ultimately included. Similarly, 11 clinical studies were finally included. Two authors independently screened trials. Lesion volume and modified neurological severity scores (mNSSs) were regarded as outcome measures for preclinical studies. The composite weighted mean [95% confidence interval (CI)] effect sizes for lesion volume, percentage of lesion volume, and mNSSs were -46.59 (-62.04 to -31.15; P < 0.001), -13.18 (-25.62 to -0.73; P = 0.04), and -1.85 (-2.17 to -1.53; P < 0.001), respectively. Our analysis revealed that all three outcomes were significantly more favorable in the stem cell group than in the control group. Barthel index (BI) values, modified Rankin scale (mRS) scores, National Institutes of Health Stroke Scale (NIHSS) scores, and Fugl-Meyer assessment (FMA) scores were regarded as outcome measures for human studies. Our results were as follows: NIHSS [mean differences, MDs = -2.57, 95% CI (-3.45 to -1.68), I2 = 51%, P < 0.001]; BI [MD = 7.93, 95% CI (3.11 to 12.75), I2 = 59%, P = 0.001]; mRS [MD = -0.53, 95% CI (-0.73 to -0.28), I2 = 0%, P < 0.001]; FMA [MD = 5.50, 95% CI (2.05 to 8.95), I2 = 15%, P = 0.002]. These results suggest that stem cell transplantation was associated with significantly better outcomes than control treatment. Adverse reactions such as mild headache and fever resolved shortly after treatment. Stem cell transplantation can significantly improve neurological deficits and quality of life in patients with ischemic stroke, without severe adverse reactions. Our results also suggest that such treatment is most effective when provided earlier and through the intravenous route.

Oncostatin M-induced upregulation of SDF-1 improves Bone marrow stromal cell migration in a rat middle cerebral artery occlusion stroke model.

Bone marrow-derived mesenchymal stem cells (BMSCs) exhibit potential regenerative effects on the injured brain. However, these effects are constrained by their limited ability to migrate to the injured site. Oncostatin M (OSM) has been shown to affect the proliferation and migration of mesenchymal stem cells. Therefore, in the present study, we explored whether OSM improves BMSC migration and secretion of growth factors and cytokines in a rat middle cerebral artery occlusion (MCAO) stroke model. The effect of OSM on the proliferation and apoptosis of rat BMSCs was first assessed in vitro, and the gene and secretion levels of factors related to cell nutrition and migration, such as SDF-1 and VEGF, were detected. To further explore underlying pathways triggered by OSM, BMSCs were treated with OSM in the presence or absence of inhibitors of the STAT3 and ERK pathways. Effects of OSM on SDF-1 expression in astrocytes and BMSC migration were also evaluated. In the rat MCAO model, OSM secretion levels were detected in the brain for up to 72 h after model establishment. Ventricle injection of OSM alone or OSM combined with caudal vein graft of BMSCs was then performed in MCAO stroke rats. After 72 h, production of SDF-1 and grafted BMSCs was detected in the lesion areas of the brain, and the nerve function score was evaluated. We found that the production of OSM continually increased in the brains of MCAO rats from 12 h to 72 h. OSM significantly upregulated SDF-1 in BMSCs via the STAT3 and ERK pathways and significantly promoted the expression of VEGF and MMP-2. OSM also promoted the secretion of SDF-1 in astrocytes through the STAT3 and ERK pathways to in turn enhance BMSC migration. Combination treatment with OSM and BMSCs in MCAO rats increased the migration efficiency of BMSCs in the brain, which significantly improved neurofunctional recovery while reducing the expression of inflammatory mediators and promoting the secretion of nutrition factors. Overall, these results show that OSM is highly expressed in the brains of MCAO stroke rats and can upregulate SDF-1 to promote BMSC migration. Thus, combination treatment with OSM and BMSCs improves the graft efficiency of BMSCs and neurofunctional recovery.

Blocking the CD47-SIRPα axis by delivery of anti-CD47 antibody induces antitumor effects in glioma and glioma stem cells.

Tumor initiating cells or cancer stem cells (CSCs) play an important role in the initiation, development, metastasis, and recurrence of tumors. However, traditional therapies have limited effects against CSCs and targeting these cells is crucial when developing new therapeutic strategies against cancer. One potentially targetable factor is CD47, a member of the immunoglobulin superfamily. This protein acts as an anti-phagocytic "don't eat me" signal and is often found expressed by cancer cells, particularly CSCs. CD47 functions by activating signal regulatory protein-α (SIRP-α) expressed on macrophages, preventing phagocytosis. However, the role of CD47 in glioma stem cells (GSCs) has been not been thoroughly investigated. Our study therefore examined the expression and function of this protein in glioma cells and GSCs. We found that CD47 was highly expressed on glioma cells, especially GSCs, and that expression associated with worse clinical outcomes. We also found that CD47+ glioma cells possessed stem/progenitor cell-like characteristics and knocking down CD47 expression resulted in a reduction in these characteristics. Treatment with anti-CD47 antibody led to increased phagocytosis of glioma cells and GSCs by macrophages. We next examined the effects of anti-CD47 antibody on glioma cells/GSCs in an immune competent mouse glioma model, revealing significant inhibition of tumor growth and prolonged survival times. Importantly, there were no apparent side effects in the animal model. In summary, we have shown that CD47 is a potentially safe and effective therapeutic target for glioma.

Transplantation of adipocyte-derived stem cells in a hydrogel scaffold for the repair of cortical contusion injury in rats.

Adipocyte-derived stem cells have emerged as a novel source of stem cell therapy for their autologous and readily accessible and pluripotent potential to differentiate into different lineages such as neural stem cells (NSCs) and endothelial progenitor cells (EPCs). Transplantation of NSCs and EPCs has been promising for the repair of brain injury. We explored using co-transplanted hydrogel scaffold to improve the survival of the transplanted cells and recovery of neurological function. Adult Wistar rats were transplanted with EPC-hydrogel, NSC-hydrogel, NSC-EPC-hydrogel, EPC only, or NSC only 7 days after cortical contusion injury. Behavioral tests were performed to evaluate neurological function before, and 1, 2, 3, and 4 weeks after transplantation. Size of injury, extent of vascularization, as well as the survival and differentiation of the transplanted EPCs and NSCs, were evaluated at week 5. All transplantation groups displayed significantly better neurological function compared with the control groups. Improved neurological function correlated with significantly smaller injury volumes than that of the saline group. Using immunostaining, we have shown that while transplanted NSCs differentiated into both neurons and astrocytes, the EPCs were incorporated into vessel epithelia. The extent of reactive gliosis (based on glial fibrillary acidic protein immunostaining) was significantly reduced in all treatment groups (NSC-EPC-hydrogel, NSC-hydrogel, and EPC-hydrogel) when compared with the saline group, with the highest reduction in the NSC-EPC-hydrogel transplantation group. Thus, co-transplantation of hydrogel scaffold provides a more conducive environment for the survival and differentiation of NSCs and EPCs at the site of brain injury, leading to improved vascularization and better recovery of neurological function.

Nitric oxide-mediated immunosuppressive effect of human amniotic membrane-derived mesenchymal stem cells on the viability and migration of microglia.

Human amniotic membrane-derived mesenchymal stem cells (AMSCs) are considered a novel and promising source of stem cells for cell replacement-based therapy. Current research is mostly limited to investigating the cellular differentiation potential of AMSCs, while few have focused on their immunosuppressive properties. This study is aimed at exploring and evaluating the immunosuppressive effect of human AMSCs on the viability and migratory properties of microglia. We found, from results of cell viability assays, that AMSCs can reduce the activity of inflammatory cells by secreting nitric oxide (NO). Also, based on results from wound healing and transwell migration assays, we show that AMSCs can inhibit the migration of human microglia as well as the mouse microglial cell line BV2, suggesting that they have the ability to inhibit the recruitment of certain immune cells to injury sites. Furthermore, we found that NO contributes significantly to this inhibitory effect. Our study provides evidence that human AMSCs can have detrimental effects on the viability and migration of microglia, through secretion of NO. This mechanism may contribute to anti-inflammatory processes in the central nervous system.

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.

Bone marrow-derived mesenchymal stem cells maintain the resting phenotype of microglia and inhibit microglial activation.

Many studies have shown that microglia in the activated state may be neurotoxic. It has been proven that uncontrolled or over-activated microglia play an important role in many neurodegenerative disorders. Bone marrow-derived mesenchymal stem cells (BMSCs) have been shown in many animal models to have a therapeutic effect on neural damage. Such a therapeutic effect is attributed to the fact that BMSCs have the ability to differentiate into neurons and to produce trophic factors, but there is little information available in the literature concerning whether BMSCs play a therapeutic role by affecting microglial activity. In this study, we triggered an inflammatory response situation in vitro by stimulating microglia with the bacterial endotoxin lipopolysaccharide (LPS), and then culturing these microglia with BMSC-conditioned medium (BMSC-CM). We found that BMSC-CM significantly inhibited proliferation and secretion of pro-inflammatory factors by activated microglia. Furthermore, we found that the phagocytic capacity of microglia was also inhibited by BMSC-CM. Finally, we investigated whether the induction of apoptosis and the production of nitric oxide (NO) were involved in the inhibition of microglial activation. We found that BMSC-CM significantly induced apoptosis of microglia, while no apoptosis was apparent in the LPS-stimulated microglia. Our study also provides evidence that NO participates in the inhibitory effect of BMSCs. Our experimental results provide evidence that BMSCs have the ability to maintain the resting phenotype of microglia or to control microglial activation through their production of several factors, indicating that BMSCs could be a promising therapeutic tool for treatment of diseases associated with microglial activation.

Up-regulation of the transient A-type K+ current (IA) in the differentiation of neural stem cells of the early postnatal rat hippocampus.

BACKGROUND: Neural stem cells (NSCs) not only are essential to cell replacement therapy and transplantation in clinical settings, but also provide a unique model for the research into neurogenesis and epigenesis. However, little attention has been paid to the electrophysiological characterization of NSC development. This work aimed to identify whether the morphological neuronal differentiation process in NSCs included changes in the electrophysiological properties of transient A-type K(+) currents (I(A)). METHODS: NSCs were isolated from early postnatal rat hippocampus and were multiplied in basic serum-free medium containing basic fibroblast growth factor. Potassium currents were investigated and compared using whole-cell patch-clamp techniques and one-way analysis of variance (ANOVA), respectively. RESULTS: Compared with NSC-derived neurons, cloned NSCs (cNSCs) had a more positive resting membrane potential, a higher input resistance, and a lower membrane capacitance. Part of cNSCs and NSC-derived neurons possessed both delayed-rectifier K(+) currents (I(DR)) and I(A), steady-state activation of I(A) in cNSCs (half-maximal activation at (21.34 +/- 4.37) mV) occurred at a more positive voltage than in NSC-derived neurons at 1-6 days in vitro (half-maximal activation at (12.85 +/- 4.19) mV). CONCLUSIONS: Our research revealed a developmental up-regulation of the I(A) component during differentiation of postnatal NSCs. Together with the marked developmental up-regulation of I(DR) in vitro neuronal differentiation we have previously found, the voltage-gated potassium channels may participate in neuronal maturation process.

Study on the proliferation and drug-resistance of human brain tumor stem-like cells.

Brain tumor stem-like cells (BTSLCs) have been implied to play an important role in genesis and development of glioma. However, their characteristics on proliferation and drug-resistance are uncertain thoroughly. In this experiment, some of the biological characteristics about BTSLCs were explored. Twenty cases of different grades of human glioma tissues were obtained from clinic. The primary glioma cells were collected and CD133(+) cells from them were purified by magnetic cell sorting assay. The BTSLCs were identified by testing the expression of CD133, Nestin, NSE, and GFAP, along with the culture process. WST-8 assay kit was used to evaluate the proliferating situation of CD133(+) cells in the different grade gliomas, and to compare the drug-resistance between the CD133(+) and CD133( - ) cells in the medium containing different concentrations of teniposide (VM-26). The results showed that the CD133(+) cells could regenerate by self-renewal, then generate and different into NSE(+) and GFAP(+) cells, respectively. CD133(+) cells in the high grade of gliomas showed the faster generation than the ones in the low grade. The number of survived CD133(+) cells in the medium containing VM-26 was much more than the CD133(-) ones in it. Therefore, it was implied that the CD133(+) BTSLCs existed in the glioma tissues possessed the more tolerant ability to the VM-26, and could proliferate much more easily in the high-grade glioma.

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.

[Prokaryotic expression, purification of human LINGO-1(aa76-319) and preparation of its polyclonal antibody].

OBJECTIVE: To express and purify the fusion protein of extracellular domain of human Ig domain-containing, neurite outgrowth inhibitor (Nogo) receptor-interacting protein-1 (LINGO-1(aa76-319)) in prokaryotic cells and prepare the rabbit anti-LINGO-1 polyclonal antibody (pAb). METHODS: The 732 bp DNA sequence of hLINGO-1(aa76-319) was obtained from pCMV-SPORT6 by PCR and inserted into pET30a(+) plasmid to construct the prokaryotic expression plasmid pET30a(+)-hLINGO-1(aa76-319), which was subsequently transformed into E.coli. The target fusion protein was expressed with IPTG induction and purified by Ni(2+)-NTA affinity chromatography column. The antiserum against hLINGO-1(aa76-319) was obtained from the rabbits immunized with hLINGO-1(aa76-319), and the titer of the pAb was determined using enzyme linked immunosorbent assay (ELISA) and its specificity identified using Western blotting. RESULTS: The prokaryotic expression plasmid pET30a(+)-hLINGO-1(aa76-319) was constructed successfully. Efficient expression of the target fusion protein was achieved with IPTG induction at the optimal concentration of 0.4 mmol/L and culture temperature at 37 degrees celsius; for 2.5 h. The hLINGO-1(aa76-319) fusion protein was effectively expressed in E.coli as inclusion bodies, and the soluble protein was obtained through denaturation and refolding procedures, and the purified fusion protein showed a purity above 90%. The titer of the anti-hLINGO-1(aa76-319) pAb obtained by immunizing the rabbits with the purified protein reached 1:1.6x10(6), and Western blotting confirmed its good specificity. CONCLUSION: The fusion protein hLINGO-1(aa76-319) with high purity has been obtained and the anti-hLINGO-1(aa76-319) pAb obtained shows a high titer and good specificity, which provide important experimental basis for further functional investigation of LINGO-1.