Reprogramming Glial Cells into Functional Neurons for Neuro-regeneration: Challenges and Promise / 神经科学通报·英文版

The capacity for neurogenesis in the adult mammalian brain is extremely limited and highly restricted to a few regions, which greatly hampers neuronal regeneration and functional restoration after neuronal loss caused by injury or disease. Meanwhile, transplantation of exogenous neuronal stem cells into the brain encounters several serious issues including immune rejection and the risk of tumorigenesis. Recent discoveries of direct reprogramming of endogenous glial cells into functional neurons have provided new opportunities for adult neuro-regeneration. Here, we extensively review the experimental findings of the direct conversion of glial cells to neurons in vitro and in vivo and discuss the remaining issues and challenges related to the glial subtypes and the specificity and efficiency of direct cell-reprograming, as well as the influence of the microenvironment. Although in situ glial cell reprogramming offers great potential for neuronal repair in the injured or diseased brain, it still needs a large amount of research to pave the way to therapeutic application.

Reprogramming Glial Cells into Functional Neurons for Neuro-regeneration: Challenges and Promise / 神经科学通报·英文版

The capacity for neurogenesis in the adult mammalian brain is extremely limited and highly restricted to a few regions, which greatly hampers neuronal regeneration and functional restoration after neuronal loss caused by injury or disease. Meanwhile, transplantation of exogenous neuronal stem cells into the brain encounters several serious issues including immune rejection and the risk of tumorigenesis. Recent discoveries of direct reprogramming of endogenous glial cells into functional neurons have provided new opportunities for adult neuro-regeneration. Here, we extensively review the experimental findings of the direct conversion of glial cells to neurons in vitro and in vivo and discuss the remaining issues and challenges related to the glial subtypes and the specificity and efficiency of direct cell-reprograming, as well as the influence of the microenvironment. Although in situ glial cell reprogramming offers great potential for neuronal repair in the injured or diseased brain, it still needs a large amount of research to pave the way to therapeutic application.

The therapeutic effect of G-CSF-mobilized autologous stem cells on radiation pulmonary injury in mice / 中华放射医学与防护杂志

Objective To investigate the effects of G-CSF-mobilized autologous stem cells in the prevention of radiation pulmonary injury.Methods Mice were divided into control group,irradiation group and treatment group.Mouse model of pulmonary fibrosis was established by exposing chest to a single dose of 14 Gy.Animals in the treatment group received recombinant human G-CSF (250 μg/kg daily for 5 d) before the irradiation in order to mobilize autologous stem cells in vivo.The general condition and mortality were documented after radiation injury.The pathological study with histological scoring,Masson staining and Sirius red staining with polarized light analysis were used to identify lung injury and the potential benefit of stem cell mobilization.Results Local chest irradiation of a single dose of 14 Gy was a suitable dose to create radiation-induced pulmonary fibrosis in mice.The death rate was 37.5％,which mainly happened around 11 weeks after injury.In contrast,all of the animals in G-CSF treated group survived.The ratio of lung to body mass was significantly increased in both irradiation group and treatment group (F =23.20,P＜0.05) around 3 months after the injury,with a higher ratio in irradiation group than that in treatment group (P＜0.05).Histological scoring for alveolar inflammation at 3 months after injury revealed statistically significant difference in irradiation group and treatment group compared with control group (F=11.93,P＜ 0.05).At this time point,the pathological observation showed lung tissue degeneration and necrosis with alveolitis and interstitial inflammation,as well as fibroblasts proliferation and focal collagen deposition in alveolar septa.At 4 month after the injury,the inflammation ininterstitial tissue was receded,but fibrosis and collagen deposition were significantly increased.In addition,at 3 and 4 months afterinjury,the pulmonary fibrosis was aggravated in irradiation group (F=28.73,16.85,P＜0.05),and significantly alleviated in the treatment group (P＜0.05).The similar results were confirmed in collagen content analysis (IOD) by Sirius red staining and image analysis (F =17.70,17.79,P＜ 0.05).Conclusions Autologous mobilization of stem cells could prevent the death of radiation-injured animals possibly by alleviating early lung injury and interstitial inflammation as well as the late pulmonary fibrosis,suggesting a therapeutic potential of autologous stem cell mobilization in radiation pulmonary fibrosis.

Cultivation of laboratory-based biomedical graduates from the perspective of supervisors / 中华医学教育探索杂志

Laboratory research training is pivotal for the cultivation of biomedical postgraduates. Supervisors' educational and managing skills have great impacts on the quality of their cultivation to postgraduates. Recently, many prominent biomedical experts in stem cell field all over the world fully discussed the way for cultivating biomedical postgraduates, including the educational conception, supervisors' responsibilities and guiding way, etc., they have reached a certain consensus in multiple aspects, such as inspiring students' potential ability, supporting diversified career development and creating a good laboratory atmosphere. Moreover, they shared some ways of guiding with personal characteristic and strong operability. Herein, we reviewed and summarized their viewpoints and comments based on our experiences, expecting to provide useful references for biomedical postgraduates' cultivation in China.

Cultivation of laboratory-based biomedical graduates from the perspective of supervisors / 中华医学教育探索杂志

Laboratory research training is pivotal for the cultivation of biomedical postgraduates.Supervisors' educational and managing skills have great impacts on the quality of their cultivation to postgraduates.Recently,many prominent biomedical experts in stem cell field all over the world fully discussed the way for cultivating biomedical postgraduates,including the educational conception,supervisors' responsibilities and guiding way,etc.,they have reached a certain consensus in multiple aspects,such as inspiring students' potential ability,supporting diversified career development and creating a good laboratory atmosphere.Moreover,they shared some ways of guiding with personal characteristic and strong operability.Herein,we reviewed and summarized their viewpoints and comments based on our experiences,expecting to provide useful references for biomedical postgraduates' cultivation in China.

Protective effect of atorvastatin on radiation-induced endothelial cell injury / 中华放射医学与防护杂志

Objective To explore the protective effect of atorvastatin on irradiated endothelium and the thrombomodulin(TM)expression.Methods Cultured human coronary artery endothelial cells(HCAEC)and human umbilical vein endothelial cells(HUVEC)were treated by atorvastatin at the final concentration of 10 μmol/ml for 10 min,and then irradiated with 2 and 25 Gy.Cell cycles status and TM expression were quantitatively measured by flow cytometry 24 hours after irradiation.Protein C activation in endothelial cells was also assessod.Results After administration with atorvastatin for 24 h,the TM expression increased by 77%,59% and 61% in normal control group,2 Gy group and 25 Gy group,respectively(t=27.395,26.420,58.065;P=0.000).The protein C levels decreased by 23% and 34% compared with the normal group post-irradiation to 2 and 25 Gy,but increased by 79% and 76% compared with the irradiated control group after administration with atorvastatin.The rates of cell apoptosis decreased by 6% and 16% in 2 Gy and 25 Gy groups,respectively after administration with atorvastatin for 24 h(t=4.178,17.863;P=0.000).Conclusions Atorva statin can protect endothelia cell from irradiation-induced apeptosis by increasing TM expression and protein C activation.

The roles of PKCO signaling pathway in the proliferation and differentiation of the γδT lymphocytes stimulated by Mycobacterium tuberculosis antigen / 中华微生物学和免疫学杂志

Objective To explore the roles of PKCθ(protein kinase Cθ)signaling pathway on the activation,proliferation and TH1/TH2 cytokines production of the γδT lymphocytes stimulated by Mycobacterium tuberculosis antigen(Mtb-Ag) in vitro.Methods Peripheral blood mononuclear cells(PBMC)were pretreated with or without Rottlerin at 5.0 μmol/L,and stimulated with Mtb-Ag and cultured in rhIL-2 containing medium.After different time of culture,activation molecules and cytokines production of γδT cells were measured by flow cytometry.The proliferation proportion and the percentage of each generation of γδT cells were determined by carboxylfluoreseein diacetate succinmidyl ester(CFSE)labeling technique and flow cytometry.Results After 3d of stimulation with Mtb-Ag,the expression rates of CD69 and CD25 of γδT cells were 46.2%and 45.6%,respectively.Pretreatment of 5.0 μmol/L Rottlerin markedly inhibited the both expressions of CD69 and CD25 in γδT cells(P＜0.01).After stimulation and expansion in vitro for 5,10,and 15 d,the percentages of the γδT cell were 9.6%,54.6%and 82.4%,respectively.There was a few γδT cells in propagation on the 5th day of culture,and almost all γδT cell divisions were above 6 generations on the 10th and 15th day of culture.Pretreatment of the Rotflerin significantly suppressed the γδT cell proliferation,but after 10 d culture,there were still a few parts of γδT cells in propagation.Meanwhile,after 7,14,and 21d of culture,upon stimulation with PMA+Ionomycin,the IFN-γ producing-γδT cells were about 80%at all times.But only after 21d culture,IL-4-producing γδT cells was 2.6%.,The percentage of IFN-γ producing γδT cells markedly reduced in Rottlerin group(P＜0.01).IL-4 secretion of the γδT cells was almost completely blocked.Conclusion PKCO signal pathway involves in activation,proliferation and differentiation of the γδT lymphocytes stimulated by Mtb-Ag.

Transdifferentiation of allotype BMSCs into hepatocytes in bone marrow chimeric mice / 第三军医大学学报

Objective To detect whether mice bone marrow mesenchymal stem cells(BMSCs)can contribute to the regeneration of hepatocytes in bone marrow chimeric mice.Methods Female recipient mice(C57BL/6J)underwent whole body gamma-ray irradiation with a dose of 10 Gy to ablate their bone marrow,followed by immediate tail vein injection of BMSCs isolated from male GFP transgenic mice.Animals were killed at different phase points:1 week,1 month,and 3 months.Using fluorescence microscope we directly observed GFP-positive cells in the liver frozen sections,and we also prepared the parafilm sections to detect the GFP-positive cells and the coexpression of GFP and Alb,CK18 by immunohistochemistry and immunofluorescence respectively.Results We found numerous GFP-positive cells in recipient mice liver at 1 week after BMSCs transplantation,some at 1 month and seldom at 3 months.There were some cells coexpressing GFP and Alb,CK18 at all the phase points.Conclusion Allotype BMSCs can differentiate into Alb and CK18 positive hepatocytes in bone marrow chimeric mice,which will become an ideal cell resource for liver tissue project.

Construction of eukaryotic expressing vector pEGFP-N1/PDGF-A for transducting Dermis-derived mesenchymal stem cells / 第三军医大学学报

Objective To clone platelet-derived growth factor A chain (PDGF-A) gene and insert PDGF-A gene into. Enhanced green fluorescent protein (EGFP) vector and then transformed into dermis-drived mesenchymal stem cells (DMSCs). Methods cDNA clones encoding human PDGF-A gene were isolated from a human hepatoma cell line mRNA by reverse transcription-polymerase chain reaction (RT-PCR). The PCR amplified fragment of PDGF-A gene was cloned into pMD18-T vector. The eukaryotic expression vector pEGFP-N1/PDGF-A was constructed by subcolone PDGF-A gene into pEGFP-N1 vector. PDGF-A gene was transfected into DMSCs with the help of Fugene 6 transfection reagent. Results Full cDNA sequence encoding human PDGF-A gene had been cloned, which sequence was consistent with the reported sequence in GenBank by sequence assaying. Conclusion cDNA sequence encoding human PDGF-A gene was successfully cloned into pEGFP-N1. The transient expression of PDGF-A gene in DMSCs has been realized.

Serum from rat exposed to radiation,burn,or combined injury can stimulate the PI3K/Akt pathway of IEC-6 cells / 第三军医大学学报

Objective To explore the activation of PI3k/Akt pathway of serum deprived IEC-6 cells by the serum of rats exposed to single radiation,burn or combined injury.Methods The IEC-6 cells were cultured in serum deprived media for 24 h,and stimulated by the serum of rats exposed to single radiation(~(60)Co ? ray at dose of 9 Gy),single burn(exposure to 5 kW tungsten-halogen light till whole body Ⅲ degree burn) or combined injury(burn first and radiation),and the cells stimulated by the serum from the normal rats and serum starved cells served as the control group.The total proteins of different group cells were extracted and the levels of phosphorylation of Akt were tested by Western blotting.The differentially expressed low mass proteins in the serums were detected by SELDI proteinchip technology,and primarily analyzed by related software as well as bioinformatic methods.Results The level of phosphorylation of Akt in the IEC-6 cells stimulated by serum from rats exposed to single radiation,single burn or combined injury was higher than in the cells stimulated by the serum from normal rats,in which the burn serum caused the highest level.As compared to burn rat serum,the serum of radiation and combined injury had 13 and 6 differentially expressed protein peaks respectively.Conclusion All the serums from rats exposed to different kinds of damage agents could activate the PI3K/Akt pathway of IEC-6 cells efficiently.The special components of burnt rat serum may contribute to the highest effect on the phosphorylation of Akt.

Construction of subtractive cDNA library for differentially expressed genes in rat intestinal epithelial cells exposed to high-dose radiation by suppression subtractive hybridization / 第三军医大学学报

Objective To clone and identify the differentially expressed genes of rat intestinal epithelial cell line (IEC 6) before and after exposure to high dose radiation so as to provide proof for the investigation of the molecular mechanisms in the repair of radiation damage of intestinal epithelial cells. Methods A subtractive cDNA library for differentially expressed genes was constructed by suppression subtractive hybridization (SSH) and T/A cloning technique after IEC 6 cells were exposed to radiation at the dose of 35 Gy ? ray. The expressed sequence tag (EST) library was screened by reverse Northern hybridization. Positive clones were sequenced and the similarity was searched against the DNA database in GenBank. Limited clones were identified by Northern hybridization. Results More than 2 000 white clones were harvested after the library amplification. Ninety six of them were randomly picked out for PCR amplification, and 15 positive clones which corresponded to 12 individual genes were identified by reverse Northern hybridization. These genes were involved in cell skeleton, cell stress, cell cycle control, and signal transduction, etc. In addition, a novel cDNA sequence was also obtained. Conclusion A subtractive cDNA library for differentially expressed genes in IEC 6 cells exposed to the radiation at the dose of 35 Gy ? ray has been successfully constructed with SSH and T/A clone techniques. Several positive ESTs which correspond to genes involving in cell skeleton, cell stress, cell cycle control, and signal transduction are identified. These genes may play important roles in the process of the damage and repair of the intestinal epithelial cells exposed to radiation.