Yingqian Cai

Adenoviral-mediated interleukin-18 expression in mesenchymal stem cells effectively suppresses the growth of glioma in rats.

Glioma is the most common primary intracranial malignant tumor. Despite advances in surgical techniques and adjuvant radio‐ and chemotherapies, the prognosis for patients with glioma remains poor. We have explored the effects of using genetically modified mesenchymal stem cells (MSCs) to treat malignant glioma in rats. Mesenchymal stem cells isolated from Sprague–Dawley rats can directly suppress the growth of C6 cells in vitro. MSCs transplanted intratumorally can also significantly inhibit the growth of glioma and prolong survival in C6 glioma‐bearing models. MSCs producing Interleukin‐18 infected by adenoviral vector inhibited glioma growth and prolonged the survival of glioma‐bearing rats. Transplantation of IL‐18 secreting MSCs was associated with enhanced T cell infiltration and long‐term anti‐tumor immunity. Thus, IL‐18 may be an effective adoptive immunotherapy for malignant glioma. When used in conjunction with MSCs as targeting vehicles in vivo, IL‐18 may offer a promising new treatment option for malignant glioma.

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

Human Whartons 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.

Blood-brain barrier disruption induced by hemoglobin in vivo: Involvement of up-regulation of nitric oxide synthase and peroxynitrite formation.

Accumulating evidence has demonstrated that up-regulation of nitric oxide synthase (NOS) and subsequent peroxynitrite (ONOO(-)) formation exert a devastating effect on the damage of BBB in multiple diseases. However, considerably less attention has been focused on the role of NOS/ONOO(-) in BBB disruption after intracerebral hemorrhage (ICH). Using an experimental stroke model by injecting hemoglobin (Hb) into the caudate nucleus of male Sprague Dawley rats, we explored the role of NOS/ONOO(-) in BBB disruption after ICH. Brain edema content, behavioral changes, alterations of TJ proteins (claudin-5 and ZO-1), expression of neuronal NOS (nNOS), inducible NOS (iNOS) and endothelial NOS (eNOS), formation of 3-nitrotyrosine (3-NT), as well as NO production were investigated. Hb in the rat brain led to a significant brain edema production and neurological deficits. Overexpressed NOS was concomitant with large quantities of 3-NT formation. Moreover, sites of enhanced nNOS, iNOS, eNOS and 3-NT immunoreactivity were colocalized with diminished or discontinuous ZO-1 and/or claudin-5 staining as evidenced by Western blot and immunofluorescence, indicating the involvement of NOS and ONOO(-) in the BBB disruption. Meaningfully, levels of 3-NT in serum, which had a similar tendency with that of in brain tissues (r=0.934, P<0.001), had a marked correlation with brain edema content (r=0.782, P<0.001) and neurological deficits (r=0.851, P<0.001). We concluded that ONOO(-) formation by the upregulation of NOS may play a central role in promoting the BBB damage following ICH. Moreover, ONOO(-) may be a promising biomarker for the judgment or prediction of brain injury and clinical prognosis after ICH.

Comparison of adult neurospheres derived from different origins for treatment of rat spinal cord injury

This study is designed to evaluate the therapeutic effects of three types of neurospheres (NSs) derived from brain, bone marrow and adipose tissue in a rat model of spinal contusive injury. As shown by BBB locomotor rating scale and grid test, the optimal therapeutic responses generated by subventricular zone-derived NSs (SVZ-NSs), and followed by adipose-derived (AD-NSs) and bone marrow-derived NSs (BM-NSs) after being grafted into the injured spinal cord. In three cell-treated groups, very few (<1%) grafted cells survived and these survived cells mainly differentiated into oligodendrocytes at week 12 after injury. Additionally, all the cell-treated groups, especially in the SVZ-treated group showed an increase in host oligodendrocytes than control group. Moreover, the level of selective neurotrophins (NTs) in the SVZ-NSs group were significantly higher than those in the BM-NSs and AD-NSs groups, and the level of NTs in the saline group was also significantly higher than sham group. Therefore, not cell replacement or infusion but neuroprotective action associated with endogenous oligodendrocytes and NTs that active by the grafted NSs may contribute to the functional recovery.

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.

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.

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.

Vasculogenic mimicry and its clinical significance in medulloblastoma

Vasculogenic mimicry (VM), a process involving the formation of a tubular structure by highly invasive and genetically dysregulated tumor cells, can supplement the function of blood vessels to transport nutrients and oxygen to maintain the growth of tumor cells in many malignant tumors. We aimed to explore the existence of VM and its clinical significance in medulloblastoma in this study. VM was identified in 9 out of 41 (22%) medulloblastoma tissues. Immunohistochemical studies revealed that the presence of VM was associated with the expression of MMP-2, MMP-14, EphA2 and laminin 5γ2. Tumor tissues with VM were associated with lower microvessel density (MVD), which was indirect evidence of the blood supply function of VM. Survival analysis and log-rank tests showed that patients with VM had shorter overall survival time than those without VM. Multivariate analysis and the Cox proportional hazards model identified VM as independent prognostic factor for overall survival. Our results confirmed the existence of VM for the first time and revealed that VM is a strong independent prognostic factor for survival in patients with medulloblastoma.

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.

In vivo magnetic resonance tracking of Feridex-labeled bone marrow-derived neural stem cells after autologous transplantation in rhesus monkey.

Bone marrow stroma cells-derived neural stem cells (BMSCs-D-NSCs) transplantation is a promising strategy for the treatment of nervous system disorders. The development of a non-invasive method to follow the fate of BMSCs-D-NSCs in vivo is very important for the future application of this treatment. In this paper, we show for the first time, that BMSCs-D-NSCs from rhesus monkeys can be labeled in vitro with the superparamagnetic iron oxide (SPIO) contrast agent Feridex and Poly-L-lysine (PLL) without affecting morphology, cell cycle, telomerase activity, proliferation and differentiation ability of the labeled cells. Furthermore, when autografted into the striatum, these cells survived, differentiated and were incorporated into the brain, and could be reliably tracked using MRI, as confirmed by histological examination of the grafting sites with PKH(67) fluorescence. These results suggest that Feridex labeling of BMSCs-D-NSCs is feasible, efficient and safe for MRI tracing following autografting into the rhesus monkey nervous system.