Mesenchymal stem cell(MSC)-based therapy has emerged as a promising treatment for spinal cord injury(SCI),but improving the neurogenic potential of MSCs remains a challenge.Mixed lineage leukemia 1(MLL1),an H3K4me3 me...Mesenchymal stem cell(MSC)-based therapy has emerged as a promising treatment for spinal cord injury(SCI),but improving the neurogenic potential of MSCs remains a challenge.Mixed lineage leukemia 1(MLL1),an H3K4me3 methyltransferases,plays a critical role in regulating lineage-specific gene expression and influences neurogenesis.In this study,we investigated the role and mechanism of MLL1 in the neurogenesis of stem cells from apical papilla(SCAPs).We examined the expression of neural markers,and the nerve repair and regeneration ability of SCAPs using dynamic changes in neuron-like cells,immunofluorescence staining,and a SCI model.We employed a coimmunoprecipitation(Co-IP)assay,real-time RT-PCR,microarray analysis,and chromatin immunoprecipitation(ChIP)assay to investigate the molecular mechanism.The results showed that MLL1 knock-down increased the expression of neural markers,including neurogenic differentiation factor(NeuroD),neural cell adhesion molecule(NCAM),tyrosine hydroxylase(TH),βIII-tubulin and Nestin,and promoted neuron-like cell formation in SCAPs.In vivo,a transplantation experiment showed that depletion of MLL 1 in SCAPs can restore motor function in a rat SCI model.MLL1 can combine with WD repeat domain 5(WDR5)and WDR5 inhibit the expression of neural markers in SCAPs.MLL1 regulates Hairy and enhancer of split 1(HES1)expression by directly binds to HES1 promoters via regulating H3K4me3 methylation by interacting with WDR5.Additionally,HES1 enhances the expression of neural markers in SCAPs.Our findings demonstrate that MLL1 inhibits the neurogenic potential of SCAPs by interacting with WDR5 and repressing HES1.These results provide a potential therapeutic target for promoting the recovery of motor function in SCI patients.展开更多
Sequential administration and controlled release of different drugs are of vital importance for regulating cellular behaviors and tissue regeneration,which usually demands appropriate carriers like microspheres(MS)to ...Sequential administration and controlled release of different drugs are of vital importance for regulating cellular behaviors and tissue regeneration,which usually demands appropriate carriers like microspheres(MS)to control drugs releases.Electrospray has been proven an effective technique to prepare MS with uniform particle size and high drug-loading rate.In this study,we applied electrospray to simply and hierarchically fabricate sphere-in-sphere composite microspheres,with smaller poly(lactic-co-glycolic acid)MS(~8-10 lm in diameter)embedded in a larger chitosan MS(~250-300 lm in diameter).The scanning electron microscopy images revealed highly uniform MS that can be accurately controlled by adjusting the nozzle diameter or voltage.Two kinds of model drugs,bovine serum albumin and chlorhexidine acetate,were encapsulated in the microspheres.The fluorescence-labeled rhodamine-fluoresceine isothiocyanate(Rho-FITC)and ultraviolet(UV)spectrophotometry results suggested that loaded drugs got excellent distribution in microspheres,as well as sustained,slow release in vitro.In addition,far-UV circular dichroism and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS)results indicated original secondary structure and molecular weight of drugs after electrospraying.Generally speaking,our research proposed a modified hierarchically electrospraying technique to prepare sphere-in-sphere composite MS with two different drugs loaded,which could be applied in sequential,multi-modality therapy.展开更多
The coordination between neurogenesis and angiogenesis plays an important role in nerve tissue development and regeneration.Recently,using bioactive materials to drive neurogenic and angiogenic responses has gained in...The coordination between neurogenesis and angiogenesis plays an important role in nerve tissue development and regeneration.Recently,using bioactive materials to drive neurogenic and angiogenic responses has gained increasing attention.Understanding the neurovascular link between regulatory cues offers valuable insight into the mechanisms underlying nerve regeneration and the design of new bioactive materials.In this study,we utilized a dual-functionalized peptide nanofiber hydrogel presenting the brain-derived neurotrophic factor and vascular endothelial growth factor mimetic peptides RGIDKRHWNSQ(RGI)and KLTWQELYQLKYKGI(KLT)to construct an artificial neurovascular microenvironment.The dual-functionalized peptide nanofiber hydrogel enhanced the neurite outgrowth of pheochromocytoma(PC12)cells and tube-like structures formation of human umbilical vein endothelial cells(HUVECs)in vitro,and promoted rapid lesion infiltration of neural and vascular cells in a rat brain injury model.Using indirect co-culture models,we found that the dual-functionalized peptide hydrogel effectively mediated neurovascular crosstalk by regulating secretion of paracrine factors from PC12 cells and HUVECs.When the two cells types were directly co-cultured on the dua卜functionalized peptide hydrogel,the efficiency of cell-cell communication was enhanced,which further accelerated the differentiation and maturation of PC12 cells with an increased number of pseudopodia and spread morphology,and HUVECs tube-like structure formation.In summary,the dual-functionalized peptide nanofiber hydrogel successfully formed an artificial neurovascular niche to directly regulate the behaviors of neural and vascular cells and promote their neurovascular crosstalk through paracrine signaling and direct cell-cell contact.展开更多
基金the Beijing Natural Science Foundation(7222075 to Z.P.F.)National Natural Science Foundation of China(82130028 to Z.P.F.)+3 种基金the National Key Research and Development Program(2022YFA1104401 to Z.P.F.)the CAMS Innovation Fund for Medical Sciences(2019-I2M-5-031 to Z.P.F.)the Innovation Research Team Project of Beijing Stomatological Hospital,Capital Medical University(No.CXTD202204 to Z.P.F.)the Young Scientist Program of Beijing Stomatological Hospital,Capital Medical University(No.YSP202113 to C.Z.).
文摘Mesenchymal stem cell(MSC)-based therapy has emerged as a promising treatment for spinal cord injury(SCI),but improving the neurogenic potential of MSCs remains a challenge.Mixed lineage leukemia 1(MLL1),an H3K4me3 methyltransferases,plays a critical role in regulating lineage-specific gene expression and influences neurogenesis.In this study,we investigated the role and mechanism of MLL1 in the neurogenesis of stem cells from apical papilla(SCAPs).We examined the expression of neural markers,and the nerve repair and regeneration ability of SCAPs using dynamic changes in neuron-like cells,immunofluorescence staining,and a SCI model.We employed a coimmunoprecipitation(Co-IP)assay,real-time RT-PCR,microarray analysis,and chromatin immunoprecipitation(ChIP)assay to investigate the molecular mechanism.The results showed that MLL1 knock-down increased the expression of neural markers,including neurogenic differentiation factor(NeuroD),neural cell adhesion molecule(NCAM),tyrosine hydroxylase(TH),βIII-tubulin and Nestin,and promoted neuron-like cell formation in SCAPs.In vivo,a transplantation experiment showed that depletion of MLL 1 in SCAPs can restore motor function in a rat SCI model.MLL1 can combine with WD repeat domain 5(WDR5)and WDR5 inhibit the expression of neural markers in SCAPs.MLL1 regulates Hairy and enhancer of split 1(HES1)expression by directly binds to HES1 promoters via regulating H3K4me3 methylation by interacting with WDR5.Additionally,HES1 enhances the expression of neural markers in SCAPs.Our findings demonstrate that MLL1 inhibits the neurogenic potential of SCAPs by interacting with WDR5 and repressing HES1.These results provide a potential therapeutic target for promoting the recovery of motor function in SCI patients.
基金supported by National Natural Science Foundation of China(nos.31771056,81671827 and 51572144).
文摘Sequential administration and controlled release of different drugs are of vital importance for regulating cellular behaviors and tissue regeneration,which usually demands appropriate carriers like microspheres(MS)to control drugs releases.Electrospray has been proven an effective technique to prepare MS with uniform particle size and high drug-loading rate.In this study,we applied electrospray to simply and hierarchically fabricate sphere-in-sphere composite microspheres,with smaller poly(lactic-co-glycolic acid)MS(~8-10 lm in diameter)embedded in a larger chitosan MS(~250-300 lm in diameter).The scanning electron microscopy images revealed highly uniform MS that can be accurately controlled by adjusting the nozzle diameter or voltage.Two kinds of model drugs,bovine serum albumin and chlorhexidine acetate,were encapsulated in the microspheres.The fluorescence-labeled rhodamine-fluoresceine isothiocyanate(Rho-FITC)and ultraviolet(UV)spectrophotometry results suggested that loaded drugs got excellent distribution in microspheres,as well as sustained,slow release in vitro.In addition,far-UV circular dichroism and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS)results indicated original secondary structure and molecular weight of drugs after electrospraying.Generally speaking,our research proposed a modified hierarchically electrospraying technique to prepare sphere-in-sphere composite MS with two different drugs loaded,which could be applied in sequential,multi-modality therapy.
基金support from the National Key R&D Program of China(Nos.2020YFC1107600 and 2018YFB0704304)the National Natural Science Foundation of China(Nos.31771056 and 31771052)Shandong Province Key R&D Program of China(No.2019JZZY011106).
文摘The coordination between neurogenesis and angiogenesis plays an important role in nerve tissue development and regeneration.Recently,using bioactive materials to drive neurogenic and angiogenic responses has gained increasing attention.Understanding the neurovascular link between regulatory cues offers valuable insight into the mechanisms underlying nerve regeneration and the design of new bioactive materials.In this study,we utilized a dual-functionalized peptide nanofiber hydrogel presenting the brain-derived neurotrophic factor and vascular endothelial growth factor mimetic peptides RGIDKRHWNSQ(RGI)and KLTWQELYQLKYKGI(KLT)to construct an artificial neurovascular microenvironment.The dual-functionalized peptide nanofiber hydrogel enhanced the neurite outgrowth of pheochromocytoma(PC12)cells and tube-like structures formation of human umbilical vein endothelial cells(HUVECs)in vitro,and promoted rapid lesion infiltration of neural and vascular cells in a rat brain injury model.Using indirect co-culture models,we found that the dual-functionalized peptide hydrogel effectively mediated neurovascular crosstalk by regulating secretion of paracrine factors from PC12 cells and HUVECs.When the two cells types were directly co-cultured on the dua卜functionalized peptide hydrogel,the efficiency of cell-cell communication was enhanced,which further accelerated the differentiation and maturation of PC12 cells with an increased number of pseudopodia and spread morphology,and HUVECs tube-like structure formation.In summary,the dual-functionalized peptide nanofiber hydrogel successfully formed an artificial neurovascular niche to directly regulate the behaviors of neural and vascular cells and promote their neurovascular crosstalk through paracrine signaling and direct cell-cell contact.
