Introduction Cells can sense and respond to the mechanical microenvironment by converting forces into biochemical signals inside the cells,i.e.mechanotransduction<sup>[1-3]</sup>.Focal adhesions are the ma...Introduction Cells can sense and respond to the mechanical microenvironment by converting forces into biochemical signals inside the cells,i.e.mechanotransduction<sup>[1-3]</sup>.Focal adhesions are the major sites of interaction between a cell and its extracellular matrix（ECM）microenvironment,thus outside mechanical signals can be sensed at focal adhesions through transmembrane receptor integrins.In particular,it has been shown that matrix elasticity can control the cell fate<sup>[4]</sup>by modulating the interactions between ECM proteins and their receptor integrins<sup>[5,6]</sup>.For example,different rigidity of polyacrylamide（PA）gels can lead to different density of ECM ancho-展开更多
OBJECTIVE To evaluate the effects of Tong-Qiao-Huo-Xue decoction(TQHXD)on the bloodbrain barrier(BBB)permeability and the expressions of related proteins on the rats;and to analyse the constituents in the cerebrospina...OBJECTIVE To evaluate the effects of Tong-Qiao-Huo-Xue decoction(TQHXD)on the bloodbrain barrier(BBB)permeability and the expressions of related proteins on the rats;and to analyse the constituents in the cerebrospinal fluid on the rats with cerebral ischemic injury.METHODS Cerebral ischemia rats were induced by middle cerebral artery occlusion(MCAO).Adult male sprague-dawley(SD)rats were randomly divided into seven groups:sham-group;model group;nimodipine(NMP)-treated group and nao mai tai(NMT)-treated group were set as positive drug control groups;TQHXD-treated group(3,6 and 12g·kg-1body weight);The neurological function of rats was estimated by neurological defect scoring after the 1,7and 15 dafter administration.Histological structure of the brain in rats were observed by hematoxylin and eosin(H&E)staining.Ultramicrostructural features of hippocampus neurons and the opening of tight junction(TJ)of BBB in rats were observed by transmission electron microscope(TEM).Western blotting was performed to detect the expression of ZO-1,occludin,claudin-5,AQP-4 and MMP-9 in BBB after cerebral ischemia injury.Component analysis experiments:adult male SD rats were randomly divided into four groups:Distilled water was administered intragastrically sham-operated rats;Distilled water was administered intragastrically model rats by MCAO;TQHXD was administered intragatrically to rats in sham-operated group;TQHXD was administered intragestrically to rats in model group by MCAO.GC and HPLC was used to detect three compounds,namely,muscone,ligustilide and hydroxysafflor yellow A,in rats cerebrospinal fluid(CSF)after oral administration of TQHXD.Finally,samples of cerebrospinal fluid of rats in each group were compared with single medicine so as to explicit the three compounds come from which herb.RESULTS TQHXD significantly reduced the neurological defect scores.Histological examination indicated that dense neuropil and largely surviving neurons had been seen in TQHXD-treated rats.TEM observation revealed that TQHXD could significantly inhibit the damage of hippocampal neurons and reduce the opening of TJ.The decreased protein expression levels of claudin-5,occludin,ZO-1 and the increased protein expression levels of AQP-4 and MMP-9in cerebral ischemia tissue were significantly prevented by treatment of TQHXD.Analysis of experimental results showed that muscone,ligustilide and hydroxysafflor yellow A could penetrate the BBB into the CSF,and the content of the model group was lower than that of sham group after intragastric administration of TQHXD.CONCLUSION These results demonstrated that TQHXD may act as a potential neuroprotective agent against BBB damage for cerebral ischemia through protecting of hippocampus neurons,reducing the opening of TJ and decreasing the permeability of BBB by up-regulating ZO-1,occludin,claudin-5 expressions,down-regulating AQP-4 and MMP-9 expressions.The effect of TQHXD on the decrease of the opening of TJ also reduced the content of muscone,ligustilide and hydroxysafflor yellow A in cerebrospinal fluid.展开更多
Spinal cord injury repair is one of the major challenges in medicine,as it can lead to permanent loss of function of central nervous system and damage to other function of the body.Stem cell transplantation together w...Spinal cord injury repair is one of the major challenges in medicine,as it can lead to permanent loss of function of central nervous system and damage to other function of the body.Stem cell transplantation together with tissue engineering is increasingly becoming a potential choice of treatment.However,direct transplantation of stem cells without scaffolds has yielded poor clinical outcome.Here we show a strategy of using mouse embryonic stem cells(ESCs)cultured within a silk fibroin(SF)based,three-dimensional scaffold with oriented channels by a directional temperature field freezing technique and lysophilization.We find that the ESCs maintained proliferation and migrated in the scaffolds and the cells migrated fastest along the SF channels.SF scaffolds contributed to ESC differentiation into neural and glial cell like cells and expressions of the neural and glial cell markers MAP2 and GFAP were greatly elevated when retinoic acid was used as an inducing factor.Our results suggest that this approach may offer some hope in the future for spinal cord injury repair using SF scaffolds and ESCs.展开更多
It is well established that living cells and tissues respond to mechanical forces such as flow-related shear stresses in blood or interstitial space and complex tractional stresses at cell-matrix contacts and cell-cel...It is well established that living cells and tissues respond to mechanical forces such as flow-related shear stresses in blood or interstitial space and complex tractional stresses at cell-matrix contacts and cell-cell contacts.However,how different modes of forces impact mechanical and biological responses is elusive.Here we describe a strategy of using the three-dimensional magnetic twisting cytometry(3D MTC)technology to apply forces in any desired directions to the same living cell.We reveal that for a fixed stress amplitude and frequency,a live cell exhibits mechanical anisotropy and responds to a local shear stress differently from responding to a local complex stress by stretching chromatin and upregulating gene transcription to different levels,extending our previous finding on force-induced direct gene activation.This finding highlights the importance of force modes in impacting cellular mechanical and biological responses in living cells and tissues and may have implications in tissue patterning and embryonic development.展开更多
Tumor-initiating cells(TICs)are a highly tumorigenic subpopulation of solid tumor cells that play a critical role in the initiation of cancer~[1].These tumorigenic cells resist conventional chemotherapeutic drug treat...Tumor-initiating cells(TICs)are a highly tumorigenic subpopulation of solid tumor cells that play a critical role in the initiation of cancer~[1].These tumorigenic cells resist conventional chemotherapeutic drug treatment and are assumed to be playing major roles in cancer relapses after chemotherapy~[2].However,the notion of TICs has been rather controversial.A report shows that a high percentage(】25%)of human melanoma cells can generate a tumor in a NOD-SCID interleukin-2 receptor gamma chain null mouse~[3],suggesting that there is no clonal development of solid tumors,refuting the idea of TICs.We recently developed a method of isolating TICs from cancer cell lines by culturing single individual cells of B16-F1(a melanoma cell line)into 3D soft fibrin gels~[4].In addition to being able to generate local tumors in a展开更多
Despite significant progress in cancer research during the past decades,yet there are no major breakthroughs that can be translated into major benefits for the general public in terms of treatment or therapy for the c...Despite significant progress in cancer research during the past decades,yet there are no major breakthroughs that can be translated into major benefits for the general public in terms of treatment or therapy for the complex neoplastic diseases,especially for the malignant solid tumors.This depressing but indisputable fact leads to a call for new ideas to target tumor metastasis by editors of Nature Medicine<sup>[1]</sup>.The real problems are that the fundamental issues of transformation and malignancy in vivo are poorly understood.In a recent review on cancer,展开更多
Understanding the mechanism of gastrulation-the early phase in embryonic development where the blastula loses its symmetry and forms organized germ layers（i.e.endoderm,mesoderm,and ectoderm）-has long been a major ch...Understanding the mechanism of gastrulation-the early phase in embryonic development where the blastula loses its symmetry and forms organized germ layers（i.e.endoderm,mesoderm,and ectoderm）-has long been a major challenge to the field of developmental biology.A long standing objective in developmental biology is not only to direct the differentiation of ESCs into specific developmental lineages,but also to organize these differentiated lineages into spatially distinct arrangements resembling the physiological gastrulation.In vivo,research on embryo morphogenesis in lower animals has demonstrated the importance of mechanical forces<sup>[1-3]</sup>.In vitro,experiments of self-sorting utilize pairwise sorting assays where two types of differentiated germ cells are homogeneously mixed<sup>[4]</sup>.It has not been possible to study the or-展开更多
The technology of induced pluripotent stem cell(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement thera...The technology of induced pluripotent stem cell(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement therapies and drug screening,but the potential risk of tumorigenesis hampers further development and application.How to generate required differentia-ted cells without initiating tumor progression remains a huge challenge.Here we show that mouse embryonic fibroblasts could be differentiated into valvular endothelial cell(VEC)like cells.VECs are critical in valve replacements in aortic valve failure.VEC-associated gene and protein expression and functional assays were quantified for these VEC-like cells.We show that mouse embryonic fibroblasts could be converted into VEC-like cells.Our results suggest that it is possible to convert mouse embryonic fibroblasts into VEC-like cells without first reprogramming them into pluripotent stem cells,minimizing the possibility of tumorigenesis.展开更多
Recently we have synthesized a novel small retinoid molecule WYC-209 that can effectively inhibit proliferation of malignant murine melanoma tumor-repopulating cells(TRCs).The molecule can induce 100%TRCs apoptosis at...Recently we have synthesized a novel small retinoid molecule WYC-209 that can effectively inhibit proliferation of malignant murine melanoma tumor-repopulating cells(TRCs).The molecule can induce 100%TRCs apoptosis at 10μM concentration.However,how WYC-209 induces TRCs apoptosis is still elusive.Here we demonstrate that WYC-209 at>6μM concentration started to induce TRCs apoptosis primarily via the caspase 3 pathway by releasing cytochrome c from mitochondria.Interestingly,we found that at concentrations<6μM WYC-209 induced TRCs to elevate dormancy marker COUP TF1 but induced no changes in apoptosis marker P53.Furthermore,proliferation markers Ki67 and PCNA decreased with the increase of WYC-209 concentrations,suggesting that low concentrations of WYC-209 inhibit TRCs growth by inducing cell dormancy instead of causing apoptosis.In addition,TRC traction forces were almost abolished when WYC-209 concentration was at 5μM,preceding the initiation of apoptosis.Our findings demonstrate that inhibition of TRCs by anti-cancer molecule WYC-209 is concentration-dependent and WYC-209 inhibits cellular force generation of the tumor-repopulating cells before inducing apoptosis.展开更多
It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplas...It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplasmic proteins.However,increasing evidence suggests that nuclear mechanotransduction impacts nuclear activities and functions.Recently we have revealed that transgene dihydrofolate reductase(DHFR)gene expression is directly upregulated via cell surface forceinduced stretching of chromatin [2].Here we show that endogenous genes are also upregulated directly by force via integrins.We present evidence on an underlying mechanism of how gene transcription is regulated by force.We have developed a technique of elastic round microgels to quantify 3D tractions in vitro and in vivo[3].We report a synthetic small molecule(which has been stiffened structurally)that inhibits malignant tumor repopulating cell growth in a low-stiffness(force)microenvironment and cancer metastasis in mouse models without detectable toxicity[4].These findings suggest that direct nuclear mechanotransduction impacts mechanobiology and mechanomedicine at cellular and molecular levels.展开更多
基金supported in part by NIH HL098472NSF CBET0846429
文摘Introduction Cells can sense and respond to the mechanical microenvironment by converting forces into biochemical signals inside the cells,i.e.mechanotransduction<sup>[1-3]</sup>.Focal adhesions are the major sites of interaction between a cell and its extracellular matrix（ECM）microenvironment,thus outside mechanical signals can be sensed at focal adhesions through transmembrane receptor integrins.In particular,it has been shown that matrix elasticity can control the cell fate<sup>[4]</sup>by modulating the interactions between ECM proteins and their receptor integrins<sup>[5,6]</sup>.For example,different rigidity of polyacrylamide（PA）gels can lead to different density of ECM ancho-
基金The project supported by National Natural Science Foundation of China(81374005)″Twelfth Five Year″National Science and Technology Support Program(2012BAI26B03)
文摘OBJECTIVE To evaluate the effects of Tong-Qiao-Huo-Xue decoction(TQHXD)on the bloodbrain barrier(BBB)permeability and the expressions of related proteins on the rats;and to analyse the constituents in the cerebrospinal fluid on the rats with cerebral ischemic injury.METHODS Cerebral ischemia rats were induced by middle cerebral artery occlusion(MCAO).Adult male sprague-dawley(SD)rats were randomly divided into seven groups:sham-group;model group;nimodipine(NMP)-treated group and nao mai tai(NMT)-treated group were set as positive drug control groups;TQHXD-treated group(3,6 and 12g·kg-1body weight);The neurological function of rats was estimated by neurological defect scoring after the 1,7and 15 dafter administration.Histological structure of the brain in rats were observed by hematoxylin and eosin(H&E)staining.Ultramicrostructural features of hippocampus neurons and the opening of tight junction(TJ)of BBB in rats were observed by transmission electron microscope(TEM).Western blotting was performed to detect the expression of ZO-1,occludin,claudin-5,AQP-4 and MMP-9 in BBB after cerebral ischemia injury.Component analysis experiments:adult male SD rats were randomly divided into four groups:Distilled water was administered intragastrically sham-operated rats;Distilled water was administered intragastrically model rats by MCAO;TQHXD was administered intragatrically to rats in sham-operated group;TQHXD was administered intragestrically to rats in model group by MCAO.GC and HPLC was used to detect three compounds,namely,muscone,ligustilide and hydroxysafflor yellow A,in rats cerebrospinal fluid(CSF)after oral administration of TQHXD.Finally,samples of cerebrospinal fluid of rats in each group were compared with single medicine so as to explicit the three compounds come from which herb.RESULTS TQHXD significantly reduced the neurological defect scores.Histological examination indicated that dense neuropil and largely surviving neurons had been seen in TQHXD-treated rats.TEM observation revealed that TQHXD could significantly inhibit the damage of hippocampal neurons and reduce the opening of TJ.The decreased protein expression levels of claudin-5,occludin,ZO-1 and the increased protein expression levels of AQP-4 and MMP-9in cerebral ischemia tissue were significantly prevented by treatment of TQHXD.Analysis of experimental results showed that muscone,ligustilide and hydroxysafflor yellow A could penetrate the BBB into the CSF,and the content of the model group was lower than that of sham group after intragastric administration of TQHXD.CONCLUSION These results demonstrated that TQHXD may act as a potential neuroprotective agent against BBB damage for cerebral ischemia through protecting of hippocampus neurons,reducing the opening of TJ and decreasing the permeability of BBB by up-regulating ZO-1,occludin,claudin-5 expressions,down-regulating AQP-4 and MMP-9 expressions.The effect of TQHXD on the decrease of the opening of TJ also reduced the content of muscone,ligustilide and hydroxysafflor yellow A in cerebrospinal fluid.
基金supported by funds from Huazhong University of Science and Technology,Wuhan,China
文摘Spinal cord injury repair is one of the major challenges in medicine,as it can lead to permanent loss of function of central nervous system and damage to other function of the body.Stem cell transplantation together with tissue engineering is increasingly becoming a potential choice of treatment.However,direct transplantation of stem cells without scaffolds has yielded poor clinical outcome.Here we show a strategy of using mouse embryonic stem cells(ESCs)cultured within a silk fibroin(SF)based,three-dimensional scaffold with oriented channels by a directional temperature field freezing technique and lysophilization.We find that the ESCs maintained proliferation and migrated in the scaffolds and the cells migrated fastest along the SF channels.SF scaffolds contributed to ESC differentiation into neural and glial cell like cells and expressions of the neural and glial cell markers MAP2 and GFAP were greatly elevated when retinoic acid was used as an inducing factor.Our results suggest that this approach may offer some hope in the future for spinal cord injury repair using SF scaffolds and ESCs.
基金supported by funds Huazhong University of Science and Technology,Wuhan,China and from US National Institutes of Health
文摘It is well established that living cells and tissues respond to mechanical forces such as flow-related shear stresses in blood or interstitial space and complex tractional stresses at cell-matrix contacts and cell-cell contacts.However,how different modes of forces impact mechanical and biological responses is elusive.Here we describe a strategy of using the three-dimensional magnetic twisting cytometry(3D MTC)technology to apply forces in any desired directions to the same living cell.We reveal that for a fixed stress amplitude and frequency,a live cell exhibits mechanical anisotropy and responds to a local shear stress differently from responding to a local complex stress by stretching chromatin and upregulating gene transcription to different levels,extending our previous finding on force-induced direct gene activation.This finding highlights the importance of force modes in impacting cellular mechanical and biological responses in living cells and tissues and may have implications in tissue patterning and embryonic development.
基金supported by the funds from Huazhong University of Science and TechnologyUS NIH grant GM072744
文摘Tumor-initiating cells(TICs)are a highly tumorigenic subpopulation of solid tumor cells that play a critical role in the initiation of cancer~[1].These tumorigenic cells resist conventional chemotherapeutic drug treatment and are assumed to be playing major roles in cancer relapses after chemotherapy~[2].However,the notion of TICs has been rather controversial.A report shows that a high percentage(】25%)of human melanoma cells can generate a tumor in a NOD-SCID interleukin-2 receptor gamma chain null mouse~[3],suggesting that there is no clonal development of solid tumors,refuting the idea of TICs.We recently developed a method of isolating TICs from cancer cell lines by culturing single individual cells of B16-F1(a melanoma cell line)into 3D soft fibrin gels~[4].In addition to being able to generate local tumors in a
基金supported by the funds from Huazhong University of Science and TechnologyUS NIH grant GM072744
文摘Despite significant progress in cancer research during the past decades,yet there are no major breakthroughs that can be translated into major benefits for the general public in terms of treatment or therapy for the complex neoplastic diseases,especially for the malignant solid tumors.This depressing but indisputable fact leads to a call for new ideas to target tumor metastasis by editors of Nature Medicine<sup>[1]</sup>.The real problems are that the fundamental issues of transformation and malignancy in vivo are poorly understood.In a recent review on cancer,
基金supported by the funds from Huazhong University of Science and TechnologyUS NIH grant GM072744
文摘Understanding the mechanism of gastrulation-the early phase in embryonic development where the blastula loses its symmetry and forms organized germ layers（i.e.endoderm,mesoderm,and ectoderm）-has long been a major challenge to the field of developmental biology.A long standing objective in developmental biology is not only to direct the differentiation of ESCs into specific developmental lineages,but also to organize these differentiated lineages into spatially distinct arrangements resembling the physiological gastrulation.In vivo,research on embryo morphogenesis in lower animals has demonstrated the importance of mechanical forces<sup>[1-3]</sup>.In vitro,experiments of self-sorting utilize pairwise sorting assays where two types of differentiated germ cells are homogeneously mixed<sup>[4]</sup>.It has not been possible to study the or-
基金supported by funds from Huazhong University of Science and Technology
文摘The technology of induced pluripotent stem cell(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement therapies and drug screening,but the potential risk of tumorigenesis hampers further development and application.How to generate required differentia-ted cells without initiating tumor progression remains a huge challenge.Here we show that mouse embryonic fibroblasts could be differentiated into valvular endothelial cell(VEC)like cells.VECs are critical in valve replacements in aortic valve failure.VEC-associated gene and protein expression and functional assays were quantified for these VEC-like cells.We show that mouse embryonic fibroblasts could be converted into VEC-like cells.Our results suggest that it is possible to convert mouse embryonic fibroblasts into VEC-like cells without first reprogramming them into pluripotent stem cells,minimizing the possibility of tumorigenesis.
基金supported by funds from Huazhong University of Science and Technology
文摘Recently we have synthesized a novel small retinoid molecule WYC-209 that can effectively inhibit proliferation of malignant murine melanoma tumor-repopulating cells(TRCs).The molecule can induce 100%TRCs apoptosis at 10μM concentration.However,how WYC-209 induces TRCs apoptosis is still elusive.Here we demonstrate that WYC-209 at>6μM concentration started to induce TRCs apoptosis primarily via the caspase 3 pathway by releasing cytochrome c from mitochondria.Interestingly,we found that at concentrations<6μM WYC-209 induced TRCs to elevate dormancy marker COUP TF1 but induced no changes in apoptosis marker P53.Furthermore,proliferation markers Ki67 and PCNA decreased with the increase of WYC-209 concentrations,suggesting that low concentrations of WYC-209 inhibit TRCs growth by inducing cell dormancy instead of causing apoptosis.In addition,TRC traction forces were almost abolished when WYC-209 concentration was at 5μM,preceding the initiation of apoptosis.Our findings demonstrate that inhibition of TRCs by anti-cancer molecule WYC-209 is concentration-dependent and WYC-209 inhibits cellular force generation of the tumor-repopulating cells before inducing apoptosis.
基金supported by funds from National Institutes of Health,USA and Huazhong University of Science and Technology,Wuhan,Chinathe support from Hoeft Professorship at University of Illinois at Urbana-Champaign
文摘It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplasmic proteins.However,increasing evidence suggests that nuclear mechanotransduction impacts nuclear activities and functions.Recently we have revealed that transgene dihydrofolate reductase(DHFR)gene expression is directly upregulated via cell surface forceinduced stretching of chromatin [2].Here we show that endogenous genes are also upregulated directly by force via integrins.We present evidence on an underlying mechanism of how gene transcription is regulated by force.We have developed a technique of elastic round microgels to quantify 3D tractions in vitro and in vivo[3].We report a synthetic small molecule(which has been stiffened structurally)that inhibits malignant tumor repopulating cell growth in a low-stiffness(force)microenvironment and cancer metastasis in mouse models without detectable toxicity[4].These findings suggest that direct nuclear mechanotransduction impacts mechanobiology and mechanomedicine at cellular and molecular levels.
