Mesenchymal stem cells are multipotent stem cells that reside in many human tissues and organs.Mesenchymal stem cells are widely used in experimental and clinical regenerative medicine due to their capability to trans...Mesenchymal stem cells are multipotent stem cells that reside in many human tissues and organs.Mesenchymal stem cells are widely used in experimental and clinical regenerative medicine due to their capability to transdifferentiate into various lineages.However,when transplanted,they lose part of their multipotency and immunomodulatory properties,and most of them die after injection into the damaged tissue.In this review,we discuss the potential utility of melatonin in preserving mesenchymal stem cells’survival and function after transplantation.Melatonin is a pleiotropic molecule regulating critical cell functions including apoptosis,endoplasmic reticulum stress,and autophagy.Melatonin is also synthesized in the mitochondria where it reduces oxidative stress,the opening of the mitochondrial permeability transition pore and the downstream caspase activation,activates uncoupling proteins,and curtails the proinflammatory response.In addition,recent findings showed that melatonin also promotes the formation of tunneling nanotubes and the transfer of mitochondria between cells through the connecting tubules.As mitochondrial dysfunction is a primary cause of mesenchymal stem cells death and senescence and a critical issue for survival after transplantation,we propose that melatonin by favoring mitochondria functionality and their transfer through tunneling nanotubes from healthy to suffering cells could improve mesenchymal stem cellbased therapy in a large number of diseases for which basic and clinical trials are underway.展开更多
Various inorganic nanoparticles are being considered for applications in life science as fluorescent labels and for such therapeutic applications as drug delivery or targeted cell destruction. It is of importance to u...Various inorganic nanoparticles are being considered for applications in life science as fluorescent labels and for such therapeutic applications as drug delivery or targeted cell destruction. It is of importance to understand their intercellular transport behaviors and mechanisms. Here, the intercellular transport of internalized CdTe quantum dot (QD) aggregates through tunneling-nanotubes (TNTs) between human hepatocellular carcinoma cells was studied by time-resolved confocal fluorescence microscopy. TNTs are known to connect eukaryotic cells to provide important pathways for intercellular communications. The formation, shrinkage, elongation and rupture of TNTs were clearly observed by microscopy. We found TNTs contained only F-actin or both microtubules and F-actin. Two transport modes for QD aggregates through the TNTs were observed: the microtubule-based bidirectional motion and the ac-tin-dependent unidirectional motion. The mean square displacement analyses revealed that the intercellular transportations of QDs along TNTs were mediated by active processes. The bidirectional intercellular transport of QDs within lysosomes through the TNT was also observed.展开更多
Many kinds of nano particles and organic dyes as fluorescent probes have been used in the stimulated emission depletion(STED)nanoscopy.Due to high toxicity,photobleaching and non-water solubility,these fluorescent pro...Many kinds of nano particles and organic dyes as fluorescent probes have been used in the stimulated emission depletion(STED)nanoscopy.Due to high toxicity,photobleaching and non-water solubility,these fluorescent probes are hard to apply in living cell imaging.Here,we reporta new fluorescence carbon dots(FNCDs)with high photoluminescence quantum yield(56%),low toxicity,anti-photobleaching and goodwater-solubility that suitable for live-cell imaging can be obtained by doping fluorine element.Moreover,the FNCDs can stain the nucleolusand tunneling nanotubes(TNTs)in the living cell.More importantly,for STED nanoscopy imaging,the FNCDs effectively depleted backgroundsignals and improved imaging resolution.Furthermore,the lateral resolution of single FNCDs size under the STED nanoscopy is up to 22.1 nm for FNCDs deposited on a glass slide was obtained.And because of their good water dispersibility,the higher resolution of single FNCDs sizein the nucleolus of a living cell can be up to 19.7 nm.After the image optimizati on steps,the fine fluoresce nee images of TNTs diameter with ca.75 nm resolution is obtained living cell,yielding a threefold enhancement compared with that in confocal imaging.Additionally,the FNCDs show excellent photobleaching resistance after 1,000 scan cycles in the STED model.All results show that FNCDs have significant potentialfor application in STED nanoscopy.展开更多
The tunneling nanotube （TNT） is a newly discovered, long and thin tubular structure between cells. In this study, we established a co-culture system for rat primary astrocytes and C6 glioma cells and found that TNTs...The tunneling nanotube （TNT） is a newly discovered, long and thin tubular structure between cells. In this study, we established a co-culture system for rat primary astrocytes and C6 glioma cells and found that TNTs formed between them. Most of the TNTs initiated from astrocytes towards C6 glioma cells. The formation of TNTs depended on p53. In addition, hydrogen peroxide increased the number of TNTs in the co-culture system. Established TNTs reduced the proliferation of C6 glioma cells. Our data suggest that TNTs between astrocytes and glioma cells facilitate substance transfer and therefore alter the properties, including the proliferation potential, of glioma cells.展开更多
As a new method of cell-cell communication,tunneling nanotubes(TNTs)play important roles in cell-cell signaling and mass exchanges.However,a lack of powerful tools to visualize dynamic TNTs with high temporal/spatial ...As a new method of cell-cell communication,tunneling nanotubes(TNTs)play important roles in cell-cell signaling and mass exchanges.However,a lack of powerful tools to visualize dynamic TNTs with high temporal/spatial resolution restricts the exploration of their formation and cleavage,hindering the complete understanding of its mechanism.Herein,we present the first example of using stochastic optical reconstruction microscopy(STORM)to observe the tube-like structures of TNTs linking live cells with an easily prepared fluorescent dye.Because of this new imaging microscopy,the cleavage process of TNTs was observed with a high spatial resolution.展开更多
基金supported by the University of Urbino Carlo Bo(No.DR-473_2018)to WB。
文摘Mesenchymal stem cells are multipotent stem cells that reside in many human tissues and organs.Mesenchymal stem cells are widely used in experimental and clinical regenerative medicine due to their capability to transdifferentiate into various lineages.However,when transplanted,they lose part of their multipotency and immunomodulatory properties,and most of them die after injection into the damaged tissue.In this review,we discuss the potential utility of melatonin in preserving mesenchymal stem cells’survival and function after transplantation.Melatonin is a pleiotropic molecule regulating critical cell functions including apoptosis,endoplasmic reticulum stress,and autophagy.Melatonin is also synthesized in the mitochondria where it reduces oxidative stress,the opening of the mitochondrial permeability transition pore and the downstream caspase activation,activates uncoupling proteins,and curtails the proinflammatory response.In addition,recent findings showed that melatonin also promotes the formation of tunneling nanotubes and the transfer of mitochondria between cells through the connecting tubules.As mitochondrial dysfunction is a primary cause of mesenchymal stem cells death and senescence and a critical issue for survival after transplantation,we propose that melatonin by favoring mitochondria functionality and their transfer through tunneling nanotubes from healthy to suffering cells could improve mesenchymal stem cellbased therapy in a large number of diseases for which basic and clinical trials are underway.
文摘Various inorganic nanoparticles are being considered for applications in life science as fluorescent labels and for such therapeutic applications as drug delivery or targeted cell destruction. It is of importance to understand their intercellular transport behaviors and mechanisms. Here, the intercellular transport of internalized CdTe quantum dot (QD) aggregates through tunneling-nanotubes (TNTs) between human hepatocellular carcinoma cells was studied by time-resolved confocal fluorescence microscopy. TNTs are known to connect eukaryotic cells to provide important pathways for intercellular communications. The formation, shrinkage, elongation and rupture of TNTs were clearly observed by microscopy. We found TNTs contained only F-actin or both microtubules and F-actin. Two transport modes for QD aggregates through the TNTs were observed: the microtubule-based bidirectional motion and the ac-tin-dependent unidirectional motion. The mean square displacement analyses revealed that the intercellular transportations of QDs along TNTs were mediated by active processes. The bidirectional intercellular transport of QDs within lysosomes through the TNT was also observed.
文摘为了研究TNT装药在坑道内爆炸的热效应,开展了1 kg和3 kg两种质量的TNT药柱在长直坑道内的爆炸试验,采用WRe 5/26热电偶获取了不同爆心距处的响应温度—时间曲线,分析了温度峰值和传播速度随距离变化的规律,以及装药质量对温度峰值和热作用持续时间的影响。结果表明,由于爆炸产物的二次反应,响应温度在上升过程中存在一个延迟台阶;温度峰值和火球传播速度随着爆心距的增加均呈“下降-上升-下降”趋势,上升段位于8~11倍坑道等效直径段,1 kg TNT装药坑道内爆炸火球传播速度在上升段达到最大值,为24.69 m/s,在最末段速度降至最低,为4.88 m/s;1 kg TNT和3 kg TNT药柱对应的响应温度峰值分别为406℃和575℃,响应温度平均持续时间分别为2.20 s和3.30 s;试验条件下,相同爆心距处的温度峰值之比和持续时间之比均近似等于两种装药质量的立方根之比。
基金We thank X.Peng(Shenzhen University)for great assistance in tunneling nanotubes of live cell.This work was partially supported by the National Key R&D Program of China(No.2018YFC0910600)the National Natural Science Foundation of China(Nos.61975132,61775145,61525503,61620106016,61835009,and 81727804)+4 种基金China Postdoctoral Science Foundation(No.2019M650211)Guangdong Province Key Area R&D Program(No.2019B110233004)Project of Department of Education of Guangdong Province(No.2015KGJHZ002/2016KCXTD007)the Shenzhen Basic Research Project(Nos.JCYJ20170412110212234 and JCYJ20170412105003520)the Natural Science Foundation of Shenzhen University(2019108).
文摘Many kinds of nano particles and organic dyes as fluorescent probes have been used in the stimulated emission depletion(STED)nanoscopy.Due to high toxicity,photobleaching and non-water solubility,these fluorescent probes are hard to apply in living cell imaging.Here,we reporta new fluorescence carbon dots(FNCDs)with high photoluminescence quantum yield(56%),low toxicity,anti-photobleaching and goodwater-solubility that suitable for live-cell imaging can be obtained by doping fluorine element.Moreover,the FNCDs can stain the nucleolusand tunneling nanotubes(TNTs)in the living cell.More importantly,for STED nanoscopy imaging,the FNCDs effectively depleted backgroundsignals and improved imaging resolution.Furthermore,the lateral resolution of single FNCDs size under the STED nanoscopy is up to 22.1 nm for FNCDs deposited on a glass slide was obtained.And because of their good water dispersibility,the higher resolution of single FNCDs sizein the nucleolus of a living cell can be up to 19.7 nm.After the image optimizati on steps,the fine fluoresce nee images of TNTs diameter with ca.75 nm resolution is obtained living cell,yielding a threefold enhancement compared with that in confocal imaging.Additionally,the FNCDs show excellent photobleaching resistance after 1,000 scan cycles in the STED model.All results show that FNCDs have significant potentialfor application in STED nanoscopy.
基金supported by the National Natural Science Foundation of China (91132718)the Beijing Natural Science Foundation, China (7142085)
文摘The tunneling nanotube （TNT） is a newly discovered, long and thin tubular structure between cells. In this study, we established a co-culture system for rat primary astrocytes and C6 glioma cells and found that TNTs formed between them. Most of the TNTs initiated from astrocytes towards C6 glioma cells. The formation of TNTs depended on p53. In addition, hydrogen peroxide increased the number of TNTs in the co-culture system. Established TNTs reduced the proliferation of C6 glioma cells. Our data suggest that TNTs between astrocytes and glioma cells facilitate substance transfer and therefore alter the properties, including the proliferation potential, of glioma cells.
基金This work has been partially supported by the National Natural Science Foundation of China(Grant Nos.61875131,61525503,61620106016,and 61835009)Shenzhen Basic Research Project(Nos.JCYJ20170818100931714,JCYJ20180305125549234,and JCYJ20170412105003520)Shenzhen International Cooperation Research Project(No.GJHZ20180928161811821).
文摘As a new method of cell-cell communication,tunneling nanotubes(TNTs)play important roles in cell-cell signaling and mass exchanges.However,a lack of powerful tools to visualize dynamic TNTs with high temporal/spatial resolution restricts the exploration of their formation and cleavage,hindering the complete understanding of its mechanism.Herein,we present the first example of using stochastic optical reconstruction microscopy(STORM)to observe the tube-like structures of TNTs linking live cells with an easily prepared fluorescent dye.Because of this new imaging microscopy,the cleavage process of TNTs was observed with a high spatial resolution.
