Neuronal cell death and the loss of connectivity are two of the primary pathological mechanisms underlying Alzheimer's disease.The accumulation of amyloid-βpeptides,a key hallmark of Alzheimer's disease,is be...Neuronal cell death and the loss of connectivity are two of the primary pathological mechanisms underlying Alzheimer's disease.The accumulation of amyloid-βpeptides,a key hallmark of Alzheimer's disease,is believed to induce neuritic abnormalities,including reduced growth,extension,and abnormal growth cone morphology,all of which contribute to decreased connectivity.However,the precise cellular and molecular mechanisms governing this response remain unknown.In this study,we used an innovative approach to demonstrate the effect of amyloid-βon neurite dynamics in both two-dimensional and three-dimensional cultu re systems,in order to provide more physiologically relevant culture geometry.We utilized various methodologies,including the addition of exogenous amyloid-βpeptides to the culture medium,growth substrate coating,and the utilization of human-induced pluripotent stem cell technology,to investigate the effect of endogenous amyloid-βsecretion on neurite outgrowth,thus paving the way for potential future applications in personalized medicine.Additionally,we also explore the involvement of the Nogo signaling cascade in amyloid-β-induced neurite inhibition.We demonstrate that inhibition of downstream ROCK and RhoA components of the Nogo signaling pathway,achieved through modulation with Y-27632(a ROCK inhibitor)and Ibuprofen(a Rho A inhibitor),respectively,can restore and even enhance neuronal connectivity in the presence of amyloid-β.In summary,this study not only presents a novel culture approach that offers insights into the biological process of neurite growth and inhibition,but also proposes a specific mechanism for reduced neural connectivity in the presence of amyloid-βpeptides,along with potential intervention points to restore neurite growth.Thereby,we aim to establish a culture system that has the potential to serve as an assay for measuring preclinical,predictive outcomes of drugs and their ability to promote neurite outgrowth,both generally and in a patient-specific manner.展开更多
BACKGROUND： Notch signaling regulates bone marrow mesenchymal stem cell （MSC） proliferation, differentiation, and apoptosis, Notch signaling and Rho kinase signaling exhibit a crosstalk phenomenon with JAK/STAT, an...BACKGROUND： Notch signaling regulates bone marrow mesenchymal stem cell （MSC） proliferation, differentiation, and apoptosis, Notch signaling and Rho kinase signaling exhibit a crosstalk phenomenon with JAK/STAT, and both participate in the neuronal dendritic spine development. Inhibition of RhoA/Rho kinase signaling may regulate MSC differentiation into neuronal-like cells. OBJECTIVE： To investigate the effect of Notch1 signaling on the differentiation of rat MSCs into neurons induced by fasudil hydrochloride （C14H17N3O2S-HCI）, a Rho kinase inhibitor, through a siRNA approach. DESIGN, TIME AND SETTING： An in vitro cytological experiment was performed in the Cell Laboratory of Henan Academy of Medical and Pharmaceutical Sciences between December 2007 and May 2009. MATERIALS： MSCs were obtained from Wistar rat femoral bone, fasudil hydrochloride was provided by -Tianjin Chase Sun Pharmaceutical Co., Ltd. Rn-notchl-siRNa, negative control siRNA （Cy3 label） and Rn-MAPK1 control siRNA were provided by QIAGEN, Coloqne, German. METHODS： The cultured MSCs were divided into non-transfected, transfected group （transfected with Rn-Notchl-siRNA）, positive control （transfected with Rn-MAPK-1 control siRNA）, and negative control （transfected with negative control siRNA） groups. Fasudil hydrochloride was applied to induce MSCs to differentiate into neurons. MAIN OUTCOME MEASURES： The fluorescence expression by the transfected MSCs was observed under an inverted fluorescence microscope; the expression of Notch1 mRNA, Hesl mRNA, and MAPK1 mRNA in MSCs was detected by reverse transcription polymerase chain reaction; the expression of Notch1 protein, nestin, neurofilament M, and glial fibrillary acidic protein was detected by immunocytochemistry. The viability of MSCs was detected by tetrazolium bromide assay. RESULTS： MSC fluorescence increased following a 72-hour siRNA transfection, with transfection efficiencies of up to （0.91 ± 0.04）; the Notch1 mRNA and Hesl mRNA expressed by transfected MSCs was significantly decreased （P 〈 0.05） compared with non-transfected cells. Fasudil hydrochloride induced MSCs to differentiate into neurons with greater efficiency in the transfected group （P 〈 0.05）. CONCLUSION： Fasudil hydrochloride induces rat MSCs to differentiate into neurons; inhibition of Notch1 signaling and Hesl expression may jointly promote the differentiation of MSCs into neurons.展开更多
Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and oste...Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells remains unclear. No results at the cellular level have been reported. In this study, dorsal root ganglion neurons （sensory neurons） from Sprague-Dawley fetal rats were co-cultured with bone marrow mesenchymal stem cells transfected with green fluorescent protein 3 weeks after osteo- genic differentiation in vitro, while osteoblasts derived from bone marrow mesenchymal stem cells served as the control group. The rat dorsal root ganglion neurons promoted the prolifera- tion of bone marrow mesenchymal stem cell-derived osteoblasts at B and 5 days of co-culture, as observed by fluorescence microscopy. The levels of mRNAs for osteogenic differentiation-re- lated factors （including alkaline phosphatase, osteocalcin, osteopontin and bone morphogenetic protein 2） in the co-culture group were higher than those in the control group, as detected by real-time quantitative PCR. Our findings indicate that dorsal root ganglion neurons promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, which pro- vides a theoretical basis for in vitro experiments aimed at constructing tissue-engineered bone.展开更多
AIM:To compare gene targeting efficiencies,expression profiles,and Ca2+ handling potentials in two widely used mouse embryonic stem cell lines.METHODS:The two widely used mouse embryonic stem cell lines,R1 and HM-1,we...AIM:To compare gene targeting efficiencies,expression profiles,and Ca2+ handling potentials in two widely used mouse embryonic stem cell lines.METHODS:The two widely used mouse embryonic stem cell lines,R1 and HM-1,were cultured and maintained on Mitomycin C treated mouse embryonic fibroblast feeder cell layers,following standard culture procedures.Cells were incubated with primary and secondary antibodies before fluorescence activated cell sorting analysis to compare known pluripotency markers.Moreover,cells were harvested by trypsinization and transfected with a kinase-inactive murine Tyk2 targeting construct,following the BioRad and Amaxa transfection procedures.Subsequently,the cells were cultured and neomycin-resistant cells were picked after 13 d of selection.Surviving clones were screened twice by polymerase chain reaction(PCR) and finally confirmed by Southern blot analysis before comparison.Global gene expression profiles of more than 20 400 probes were also compared and significantly regulated genes were conf irmed by real time PCR analysis.Calcium handling potentials of these cell lines were also compared using various agonists.RESULTS:We found signif icant differences in transfection eff iciencies of the two cell lines(91% ± 6.1% vs 75% ± 4.2%,P = 0.01).Differences in the targeting efficiencies were also significant whether the Amaxa or BioRad platforms were used for comparison.We did not observe signif icant differences in the levels of many known pluripotency markers.However,our genomewide expression analysis using more than 20 400 spotted cDNA arrays identified 55 differentially regulated transcripts(P < 0.05) implicated in various important biological processes,including binding molecular functions(particularly Ca2+ binding roles).Subsequently,we measured Ca2+ signals in these cell lines in response to various calcium agonists,both in high and low Ca2+ solutions,and found signif icant differences(P < 0.05) in the regulation of Ca2+ homeostasis between the investigated cell lines.Then we further compared the detection and expression of various membrane and in-tracellular Ca2+ receptors and similarly found signif icant(P < 0.05) variations in a number of calcium receptors between these cell lines.CONCLUSION:Results of this study emphasize the importance of considering intrinsic cellular variations,during selection of cell lines for experiments and interpretations of experimental results.展开更多
基金supported by a BBSRC CASE training studentship,No.BB/K011413/1(to KG)。
文摘Neuronal cell death and the loss of connectivity are two of the primary pathological mechanisms underlying Alzheimer's disease.The accumulation of amyloid-βpeptides,a key hallmark of Alzheimer's disease,is believed to induce neuritic abnormalities,including reduced growth,extension,and abnormal growth cone morphology,all of which contribute to decreased connectivity.However,the precise cellular and molecular mechanisms governing this response remain unknown.In this study,we used an innovative approach to demonstrate the effect of amyloid-βon neurite dynamics in both two-dimensional and three-dimensional cultu re systems,in order to provide more physiologically relevant culture geometry.We utilized various methodologies,including the addition of exogenous amyloid-βpeptides to the culture medium,growth substrate coating,and the utilization of human-induced pluripotent stem cell technology,to investigate the effect of endogenous amyloid-βsecretion on neurite outgrowth,thus paving the way for potential future applications in personalized medicine.Additionally,we also explore the involvement of the Nogo signaling cascade in amyloid-β-induced neurite inhibition.We demonstrate that inhibition of downstream ROCK and RhoA components of the Nogo signaling pathway,achieved through modulation with Y-27632(a ROCK inhibitor)and Ibuprofen(a Rho A inhibitor),respectively,can restore and even enhance neuronal connectivity in the presence of amyloid-β.In summary,this study not only presents a novel culture approach that offers insights into the biological process of neurite growth and inhibition,but also proposes a specific mechanism for reduced neural connectivity in the presence of amyloid-βpeptides,along with potential intervention points to restore neurite growth.Thereby,we aim to establish a culture system that has the potential to serve as an assay for measuring preclinical,predictive outcomes of drugs and their ability to promote neurite outgrowth,both generally and in a patient-specific manner.
基金the National Natural Science Foundation of China, No. 30770758Natural Science Research Plan of Henan Provincial Education Ministry, No. 2008A320032
文摘BACKGROUND： Notch signaling regulates bone marrow mesenchymal stem cell （MSC） proliferation, differentiation, and apoptosis, Notch signaling and Rho kinase signaling exhibit a crosstalk phenomenon with JAK/STAT, and both participate in the neuronal dendritic spine development. Inhibition of RhoA/Rho kinase signaling may regulate MSC differentiation into neuronal-like cells. OBJECTIVE： To investigate the effect of Notch1 signaling on the differentiation of rat MSCs into neurons induced by fasudil hydrochloride （C14H17N3O2S-HCI）, a Rho kinase inhibitor, through a siRNA approach. DESIGN, TIME AND SETTING： An in vitro cytological experiment was performed in the Cell Laboratory of Henan Academy of Medical and Pharmaceutical Sciences between December 2007 and May 2009. MATERIALS： MSCs were obtained from Wistar rat femoral bone, fasudil hydrochloride was provided by -Tianjin Chase Sun Pharmaceutical Co., Ltd. Rn-notchl-siRNa, negative control siRNA （Cy3 label） and Rn-MAPK1 control siRNA were provided by QIAGEN, Coloqne, German. METHODS： The cultured MSCs were divided into non-transfected, transfected group （transfected with Rn-Notchl-siRNA）, positive control （transfected with Rn-MAPK-1 control siRNA）, and negative control （transfected with negative control siRNA） groups. Fasudil hydrochloride was applied to induce MSCs to differentiate into neurons. MAIN OUTCOME MEASURES： The fluorescence expression by the transfected MSCs was observed under an inverted fluorescence microscope; the expression of Notch1 mRNA, Hesl mRNA, and MAPK1 mRNA in MSCs was detected by reverse transcription polymerase chain reaction; the expression of Notch1 protein, nestin, neurofilament M, and glial fibrillary acidic protein was detected by immunocytochemistry. The viability of MSCs was detected by tetrazolium bromide assay. RESULTS： MSC fluorescence increased following a 72-hour siRNA transfection, with transfection efficiencies of up to （0.91 ± 0.04）; the Notch1 mRNA and Hesl mRNA expressed by transfected MSCs was significantly decreased （P 〈 0.05） compared with non-transfected cells. Fasudil hydrochloride induced MSCs to differentiate into neurons with greater efficiency in the transfected group （P 〈 0.05）. CONCLUSION： Fasudil hydrochloride induces rat MSCs to differentiate into neurons; inhibition of Notch1 signaling and Hesl expression may jointly promote the differentiation of MSCs into neurons.
基金supported by grants from the National Program on Key Basic Research Project of China(973 Program),No.2014CB542200the National Natural Science Foundation of China,No.31271284,81301570+2 种基金Program for New Century Excellent Talents in University of Ministry of Education of China,No.BMU20110270the Natural Science Foundation of Shandong Province of China,No.Y2008C18Yantai Science and Technology Development Program of China,No.2011207,2011209
文摘Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells remains unclear. No results at the cellular level have been reported. In this study, dorsal root ganglion neurons （sensory neurons） from Sprague-Dawley fetal rats were co-cultured with bone marrow mesenchymal stem cells transfected with green fluorescent protein 3 weeks after osteo- genic differentiation in vitro, while osteoblasts derived from bone marrow mesenchymal stem cells served as the control group. The rat dorsal root ganglion neurons promoted the prolifera- tion of bone marrow mesenchymal stem cell-derived osteoblasts at B and 5 days of co-culture, as observed by fluorescence microscopy. The levels of mRNAs for osteogenic differentiation-re- lated factors （including alkaline phosphatase, osteocalcin, osteopontin and bone morphogenetic protein 2） in the co-culture group were higher than those in the control group, as detected by real-time quantitative PCR. Our findings indicate that dorsal root ganglion neurons promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, which pro- vides a theoretical basis for in vitro experiments aimed at constructing tissue-engineered bone.
文摘AIM:To compare gene targeting efficiencies,expression profiles,and Ca2+ handling potentials in two widely used mouse embryonic stem cell lines.METHODS:The two widely used mouse embryonic stem cell lines,R1 and HM-1,were cultured and maintained on Mitomycin C treated mouse embryonic fibroblast feeder cell layers,following standard culture procedures.Cells were incubated with primary and secondary antibodies before fluorescence activated cell sorting analysis to compare known pluripotency markers.Moreover,cells were harvested by trypsinization and transfected with a kinase-inactive murine Tyk2 targeting construct,following the BioRad and Amaxa transfection procedures.Subsequently,the cells were cultured and neomycin-resistant cells were picked after 13 d of selection.Surviving clones were screened twice by polymerase chain reaction(PCR) and finally confirmed by Southern blot analysis before comparison.Global gene expression profiles of more than 20 400 probes were also compared and significantly regulated genes were conf irmed by real time PCR analysis.Calcium handling potentials of these cell lines were also compared using various agonists.RESULTS:We found signif icant differences in transfection eff iciencies of the two cell lines(91% ± 6.1% vs 75% ± 4.2%,P = 0.01).Differences in the targeting efficiencies were also significant whether the Amaxa or BioRad platforms were used for comparison.We did not observe signif icant differences in the levels of many known pluripotency markers.However,our genomewide expression analysis using more than 20 400 spotted cDNA arrays identified 55 differentially regulated transcripts(P < 0.05) implicated in various important biological processes,including binding molecular functions(particularly Ca2+ binding roles).Subsequently,we measured Ca2+ signals in these cell lines in response to various calcium agonists,both in high and low Ca2+ solutions,and found signif icant differences(P < 0.05) in the regulation of Ca2+ homeostasis between the investigated cell lines.Then we further compared the detection and expression of various membrane and in-tracellular Ca2+ receptors and similarly found signif icant(P < 0.05) variations in a number of calcium receptors between these cell lines.CONCLUSION:Results of this study emphasize the importance of considering intrinsic cellular variations,during selection of cell lines for experiments and interpretations of experimental results.
