稀土在工业、医药领域、基础研究以及在我国的广泛农用引起了人们对其生物效应机理以及可能毒性的关注.在稀土生物学效应机理及毒性的研究中,无论是在动物水平还是细胞层次,引起生物学效应的稀土物种都是一个关键问题,一直存在争议.本...稀土在工业、医药领域、基础研究以及在我国的广泛农用引起了人们对其生物效应机理以及可能毒性的关注.在稀土生物学效应机理及毒性的研究中,无论是在动物水平还是细胞层次,引起生物学效应的稀土物种都是一个关键问题,一直存在争议.本文对以动物、细胞为模型的生物效应研究中的实验条件进行分析,对生理条件下引起稀土生物学效应的可能物种提出"稀土离子池"(rare earth ion pool)模型,并对其引起生物学效应的活性物种以及与细胞膜相互作用的方式进行了探讨,以期为阐明复杂生物学体系中稀土化合物的作用机制提供思路.展开更多
Calcium phosphate nanoparticles(CaPNPs)have good biocompatibility as gene carriers;however,CaPNPs typically exhibit a low transfection efficiency.Cell penetrate peptide(TAT)can increase the uptake of nanoparticles but...Calcium phosphate nanoparticles(CaPNPs)have good biocompatibility as gene carriers;however,CaPNPs typically exhibit a low transfection efficiency.Cell penetrate peptide(TAT)can increase the uptake of nanoparticles but is limited by its non-specificity.Grafting adhesion peptide adhesion peptide on carriers can enhance their targeting.The Plekho1 gene encodes casein kinase-2 interacting protein-1(CKIP-1),which can negatively regulate osteogenic differentiation.Based on the above,we produced a Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system via hydrothermal synthesis,silanization and adsorption.The effects of this carrier system on cell endocytosis and biological effects were evaluated by cell culture in vitro.The results demonstrate that CaPNPs with 7%Mg(60 nm particle size,short rod shape and good dispersion)were suitable for use as gene carriers.The carrier system boosted the endocytosis of MG63 cells and was helpful for promoting the differentiation of osteoblasts,and the dual-ligand system possessed a synergistic effect.The findings of this study show the tremendous potential of the Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system for efficient delivery into cells and osteogenesis inducement.展开更多
Aptamers,short single DNA or RNA oligonucleotides,have shown immense application potential as molecular probes for the early diagnosis and therapy of cancer.However,conventional cell-SELEX technologies for aptamer dis...Aptamers,short single DNA or RNA oligonucleotides,have shown immense application potential as molecular probes for the early diagnosis and therapy of cancer.However,conventional cell-SELEX technologies for aptamer discovery are time-consuming and laborious.Here we discovered a new aptamer BC-3 by using an improved rapid X-Aptamer selection process for human bladder carcinoma,for which there is no specific molecular probe yet.We show that BC-3 exhibited excellent affinity in bladder cancer cells but not normal cells.We demonstrate that BC-3 displayed high selectivity for tumor cells over their normal counterparts in vitro,in mice,and in patient tumor tissue specimens.Further endocytosis pathway analysis revealed that BC-3 internalized into bladder cancer cells via clathrin-mediated endocytosis.Importantly,we identified ribosomal protein S7(RPS7)as the binding target of BC-3 via an integrated methodology(mass spectrometry,colocalization assay,and immunoblotting).Together,we report that a novel aptamer BC-3 is discovered for bladder cancer and its properties in the disease are unearthed.Our findings will facilitate the discovery of novel diagnostic and therapeutic strategies for bladder cancer.展开更多
Many particles are found in the cytoplasm area after the mixture of hydroxyapatite （HAP） nanoparticles and cultured cancer cells. The purpose of this study was to confirm whether these particles in cytoplasm are HAP...Many particles are found in the cytoplasm area after the mixture of hydroxyapatite （HAP） nanoparticles and cultured cancer cells. The purpose of this study was to confirm whether these particles in cytoplasm are HAP nanoparticles exactly. BEL7402 cells were incubated in HAP sol for 8 hours. Then, the cells were collected for specimen preparation. Transmission electron microscope （TEM）, energy dispersing spectrum （EDS） and electronic diffraction （ED） attached to TEM were used to detect the properties of the particles. It is found that many particles similar to HAP in shape are in the cytoplasm under TEM. By EDS analysis, they are the particles containing calcium （Ca） and phosphorus （P）. The classic rings of HAP crystal appear in the ED pictures of these particles. So the particles are confirmed as HAP nanoparticles. Thus, it is concluded that HAP nanoparticles as the crystal particles can be absorbed by hepatoma cells.展开更多
To analyze the kinetics and size of single exo- and endocytotic events in BY-2 protoplasts, we employed cellattached membrane capacitance measurements. These measurements revealed different modes of fusion and fission...To analyze the kinetics and size of single exo- and endocytotic events in BY-2 protoplasts, we employed cellattached membrane capacitance measurements. These measurements revealed different modes of fusion and fission of single vesicles. In about half of the observed exocytotic events, fusion occurred transiently, which facilitates rapid recycling of vesicles. In addition, transient sequential or multi-vesicular exocytosis observed in some recordings can contribute to an increase in efficiency of secretory product release. Microscopic analysis of the timescale of cellulose and pectin deposition in protoplasts demonstrates that rebuilding of the cell wall starts soon after isolation of protoplasts and that transient fusion events can fully account for secretion of the required soluble material. The capacitance measurements also allowed us to investigate formation of the fusion pore. We speculate that regulation of secretion may involve control of the length and/or size of fusion pore opening. Together, the different kinetic modes of exo- and endocytosis revealed by capacitance measurements underline the complexity of this process in plants and provide a basis for future research into the underlying mechanisms. The fact that similar fusion/fission kinetics are present in plant and animal cells suggests that many of these mechanisms are highly conserved among eukaryotes.展开更多
Cancer stem cells(CSCs)are the driving force for sustainable tumor growth and metastasis and responsible for drug resistance and cancer relapse.Nanoparticle-based drug delivery has been demonstrated to be effective in...Cancer stem cells(CSCs)are the driving force for sustainable tumor growth and metastasis and responsible for drug resistance and cancer relapse.Nanoparticle-based drug delivery has been demonstrated to be effective in combating tumor growth.However,it has been challenging to selectively eliminate CSCs due to the lack of a general signature for a spectrum of cancers.It is known that CSCs from various types of cancer show lower stiffness compared to non-CSCs.It remains unclear whether low stiffness in CSCs influences cellular uptake in nanoparticle-based drug delivery and thus the chemotherapy efficacy.Graphene quantum dot(GQD)is emerging as a promising carrier material in delivering anti-cancer drugs.We found that breast CSCs were softer than conventional cancer cells,which were further softer compared to healthy breast tissue cells.Importantly,soft CSCs uptook more GQD than conventional cancer cells,while stiff breast cancer cells with relatively low stiffness uptook more GQD than healthy breast cells.Softening cells by pharmacologically inhibiting actomyosin activity using either siRNA or actomyosin inhibitors significantly enhanced the cellular uptake of GQD in breast cancer cells but not CSCs,while stiffening cells by activating actomyosin using CA-MLCK/ROCK or actomyosin activators considerably suppressed the nanoparticle uptake in both cancer cells and CSCs.GQD could specifically target CSC because of low cell stiffness of CSC in breast cancer cell line MCF-7 and MDA-MB-231.Further regulating cell stiffness reflected that decreasing breast cancer cell stiffness by inhibiting actomyosin activity using blebbistatin could promote GQD uptake.Vice versa,stiffening cancer cell by activating actomyosin decreased GQD uptake.The attachment of anti-cancer drug doxorubicin did not alter the trend of GQD uptake in neither soften nor stiffen cancer cells.Actomyosin activity regulates cellular uptake ofGQD might through clathrin and caveolin-mediated endocytosis.Cancer cells are softer than normal cells from the same orga展开更多
Tubulobulbar Complexes (TBCs) are actin-rich structures formed between Sertoli-cells and spermatids at the time of sperm release. The main functions of the TBCs are to remove excess spermatid cytoplasm and acrosomal c...Tubulobulbar Complexes (TBCs) are actin-rich structures formed between Sertoli-cells and spermatids at the time of sperm release. The main functions of the TBCs are to remove excess spermatid cytoplasm and acrosomal contents, internalize and recycle junctional complexes by endocytosis prior to spermiation. However, in addition to recycling some of the molecules undergo lysosomal degradation. The molecular machinery involved in endocytosis at the TBCs is not well understood. To bridge this gap localization of various proteins, involved at various steps of endocytosis studied in other systems, was demonstrated in TBCs using testicular fragmented material or sections by immunoblotting and immunofluroscence. The presence of key molecules like Vamp-2, syntaxin and Lamp-2 indicates occurrence of lysosomal degradation in addition to junctional recycling at the TBCs present at the time of sperm release. TBCs are endocytic devices functioning to recycle junctional molecules or remove spermatid cytoplasm that were present between spermatids and Sertoli-cells all through the process of spermatid maturation and in turn regulate male fertility.展开更多
The cortical actin network is a mesh of filaments distributed beneath the plasmalemma that dynamically reacts in response to stimuli.This dynamic network of cortical filaments,together with motor myosin partners,adjus...The cortical actin network is a mesh of filaments distributed beneath the plasmalemma that dynamically reacts in response to stimuli.This dynamic network of cortical filaments,together with motor myosin partners,adjusts the plasmalemma tension,organizes membrane protein microdomains,remodels the cell surface and drives vesicle motion in order to fine-tune exocytosis,endocytosis and recycling of secretory vesicles.In this review,we discuss how these mechanisms work in secretory cells.展开更多
文摘稀土在工业、医药领域、基础研究以及在我国的广泛农用引起了人们对其生物效应机理以及可能毒性的关注.在稀土生物学效应机理及毒性的研究中,无论是在动物水平还是细胞层次,引起生物学效应的稀土物种都是一个关键问题,一直存在争议.本文对以动物、细胞为模型的生物效应研究中的实验条件进行分析,对生理条件下引起稀土生物学效应的可能物种提出"稀土离子池"(rare earth ion pool)模型,并对其引起生物学效应的活性物种以及与细胞膜相互作用的方式进行了探讨,以期为阐明复杂生物学体系中稀土化合物的作用机制提供思路.
基金Project(81571021)supported by the National Natural Science Foundation of ChinaProject(2018zzts944)supported by the Graduate Student Independent Exploration Innovation Fund of the Central South University,China+1 种基金Projects(2015WK3012,2018SK2017)supported by the Hunan Provincial Science and Technology Department,ChinaProject(20160301)supported by New Talent Project of the Third Xiangya Hospital of Central South University,China。
文摘Calcium phosphate nanoparticles(CaPNPs)have good biocompatibility as gene carriers;however,CaPNPs typically exhibit a low transfection efficiency.Cell penetrate peptide(TAT)can increase the uptake of nanoparticles but is limited by its non-specificity.Grafting adhesion peptide adhesion peptide on carriers can enhance their targeting.The Plekho1 gene encodes casein kinase-2 interacting protein-1(CKIP-1),which can negatively regulate osteogenic differentiation.Based on the above,we produced a Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system via hydrothermal synthesis,silanization and adsorption.The effects of this carrier system on cell endocytosis and biological effects were evaluated by cell culture in vitro.The results demonstrate that CaPNPs with 7%Mg(60 nm particle size,short rod shape and good dispersion)were suitable for use as gene carriers.The carrier system boosted the endocytosis of MG63 cells and was helpful for promoting the differentiation of osteoblasts,and the dual-ligand system possessed a synergistic effect.The findings of this study show the tremendous potential of the Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system for efficient delivery into cells and osteogenesis inducement.
基金supported by the National Natural Science Foundation of China(No.31970692)(X.Hu)the Corbett Estate Fund for Cancer Research(USA)(No.62285-531021-41800,62285-531021-51800,62285-531021-61800,and 62285-531021-71800)(E.Wu).
文摘Aptamers,short single DNA or RNA oligonucleotides,have shown immense application potential as molecular probes for the early diagnosis and therapy of cancer.However,conventional cell-SELEX technologies for aptamer discovery are time-consuming and laborious.Here we discovered a new aptamer BC-3 by using an improved rapid X-Aptamer selection process for human bladder carcinoma,for which there is no specific molecular probe yet.We show that BC-3 exhibited excellent affinity in bladder cancer cells but not normal cells.We demonstrate that BC-3 displayed high selectivity for tumor cells over their normal counterparts in vitro,in mice,and in patient tumor tissue specimens.Further endocytosis pathway analysis revealed that BC-3 internalized into bladder cancer cells via clathrin-mediated endocytosis.Importantly,we identified ribosomal protein S7(RPS7)as the binding target of BC-3 via an integrated methodology(mass spectrometry,colocalization assay,and immunoblotting).Together,we report that a novel aptamer BC-3 is discovered for bladder cancer and its properties in the disease are unearthed.Our findings will facilitate the discovery of novel diagnostic and therapeutic strategies for bladder cancer.
基金the National Natural Science Foundation of China (No.50472040)
文摘Many particles are found in the cytoplasm area after the mixture of hydroxyapatite （HAP） nanoparticles and cultured cancer cells. The purpose of this study was to confirm whether these particles in cytoplasm are HAP nanoparticles exactly. BEL7402 cells were incubated in HAP sol for 8 hours. Then, the cells were collected for specimen preparation. Transmission electron microscope （TEM）, energy dispersing spectrum （EDS） and electronic diffraction （ED） attached to TEM were used to detect the properties of the particles. It is found that many particles similar to HAP in shape are in the cytoplasm under TEM. By EDS analysis, they are the particles containing calcium （Ca） and phosphorus （P）. The classic rings of HAP crystal appear in the ED pictures of these particles. So the particles are confirmed as HAP nanoparticles. Thus, it is concluded that HAP nanoparticles as the crystal particles can be absorbed by hepatoma cells.
文摘To analyze the kinetics and size of single exo- and endocytotic events in BY-2 protoplasts, we employed cellattached membrane capacitance measurements. These measurements revealed different modes of fusion and fission of single vesicles. In about half of the observed exocytotic events, fusion occurred transiently, which facilitates rapid recycling of vesicles. In addition, transient sequential or multi-vesicular exocytosis observed in some recordings can contribute to an increase in efficiency of secretory product release. Microscopic analysis of the timescale of cellulose and pectin deposition in protoplasts demonstrates that rebuilding of the cell wall starts soon after isolation of protoplasts and that transient fusion events can fully account for secretion of the required soluble material. The capacitance measurements also allowed us to investigate formation of the fusion pore. We speculate that regulation of secretion may involve control of the length and/or size of fusion pore opening. Together, the different kinetic modes of exo- and endocytosis revealed by capacitance measurements underline the complexity of this process in plants and provide a basis for future research into the underlying mechanisms. The fact that similar fusion/fission kinetics are present in plant and animal cells suggests that many of these mechanisms are highly conserved among eukaryotes.
文摘Cancer stem cells(CSCs)are the driving force for sustainable tumor growth and metastasis and responsible for drug resistance and cancer relapse.Nanoparticle-based drug delivery has been demonstrated to be effective in combating tumor growth.However,it has been challenging to selectively eliminate CSCs due to the lack of a general signature for a spectrum of cancers.It is known that CSCs from various types of cancer show lower stiffness compared to non-CSCs.It remains unclear whether low stiffness in CSCs influences cellular uptake in nanoparticle-based drug delivery and thus the chemotherapy efficacy.Graphene quantum dot(GQD)is emerging as a promising carrier material in delivering anti-cancer drugs.We found that breast CSCs were softer than conventional cancer cells,which were further softer compared to healthy breast tissue cells.Importantly,soft CSCs uptook more GQD than conventional cancer cells,while stiff breast cancer cells with relatively low stiffness uptook more GQD than healthy breast cells.Softening cells by pharmacologically inhibiting actomyosin activity using either siRNA or actomyosin inhibitors significantly enhanced the cellular uptake of GQD in breast cancer cells but not CSCs,while stiffening cells by activating actomyosin using CA-MLCK/ROCK or actomyosin activators considerably suppressed the nanoparticle uptake in both cancer cells and CSCs.GQD could specifically target CSC because of low cell stiffness of CSC in breast cancer cell line MCF-7 and MDA-MB-231.Further regulating cell stiffness reflected that decreasing breast cancer cell stiffness by inhibiting actomyosin activity using blebbistatin could promote GQD uptake.Vice versa,stiffening cancer cell by activating actomyosin decreased GQD uptake.The attachment of anti-cancer drug doxorubicin did not alter the trend of GQD uptake in neither soften nor stiffen cancer cells.Actomyosin activity regulates cellular uptake ofGQD might through clathrin and caveolin-mediated endocytosis.Cancer cells are softer than normal cells from the same orga
文摘Tubulobulbar Complexes (TBCs) are actin-rich structures formed between Sertoli-cells and spermatids at the time of sperm release. The main functions of the TBCs are to remove excess spermatid cytoplasm and acrosomal contents, internalize and recycle junctional complexes by endocytosis prior to spermiation. However, in addition to recycling some of the molecules undergo lysosomal degradation. The molecular machinery involved in endocytosis at the TBCs is not well understood. To bridge this gap localization of various proteins, involved at various steps of endocytosis studied in other systems, was demonstrated in TBCs using testicular fragmented material or sections by immunoblotting and immunofluroscence. The presence of key molecules like Vamp-2, syntaxin and Lamp-2 indicates occurrence of lysosomal degradation in addition to junctional recycling at the TBCs present at the time of sperm release. TBCs are endocytic devices functioning to recycle junctional molecules or remove spermatid cytoplasm that were present between spermatids and Sertoli-cells all through the process of spermatid maturation and in turn regulate male fertility.
基金This work was supported by the Grants PICT 2764-2016,PICT 02849-2018 and PICT 02041-2019 from the Agencia Nacional de Promoción de la Investigación,el Desarrollo Tecnológico y la Innovación(Argentina)ICN09_022 from ICM-ANID(Chile).
文摘The cortical actin network is a mesh of filaments distributed beneath the plasmalemma that dynamically reacts in response to stimuli.This dynamic network of cortical filaments,together with motor myosin partners,adjusts the plasmalemma tension,organizes membrane protein microdomains,remodels the cell surface and drives vesicle motion in order to fine-tune exocytosis,endocytosis and recycling of secretory vesicles.In this review,we discuss how these mechanisms work in secretory cells.
