Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulatio...Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulation plays an important role in the developmental origins of osteoporosis; however, few studies have investigated the potential of epigenetic therapy to improve or rescue the osteogenic ability of bone marrow mesenchymal stem cells(BMMSCs) under osteoporotic conditions. Here, we investigated pargyline, an inhibitor of lysine-specific demethylase 1(LSD1), which mainly catalyzes the demethylation of the di- and mono-methylation of H3K4. We demonstrated that 1.5 mmol·Lpargyline was the optimal concentration for the osteogenic differentiation of human BMMSCs. Pargyline rescued the osteogenic differentiation ability of mouse BMMSCs under osteoporotic conditions by enhancing the dimethylation level of H3K4 at the promoter regions of osteogenesis-related genes. Moreover, pargyline partially rescued or prevented the osteoporotic conditions in aged or ovariectomized mouse models, respectively. By introducing the concept of epigenetic therapy into the field of osteoporosis, this study demonstrated that LSD1 inhibitors could improve the clinical practice of MSC-based bone tissue engineering and proposes their novel use to treat osteoporosis.展开更多
Diabetic wound healing impairment,a common complication of diabetes,has limited clinical treatment options and poor therapeutic outcomes,causing significant physical pain and psychological burden for patients.This stu...Diabetic wound healing impairment,a common complication of diabetes,has limited clinical treatment options and poor therapeutic outcomes,causing significant physical pain and psychological burden for patients.This study aims to accelerate wound healing by modulating cellular stress responses,offering a safe and efficient new therapeutic strategy.Herein,a seleniumcontaining polyurethane(SePU)thermo-sensitive hydrogel was synthesized,and its mechanism for promoting diabetic wound healing by activating the unfolded protein response(UPR)was elucidated.Hydroxybutyl chitosan(HBC)offers amore convenient application for SePU,with its high hydroxybutyl substitution enabling the hydrogel to undergo a rapid sol-gel transition at physiological temperatures.In vitro experiments showed that SePU thermo-sensitive hydrogel(SePU/HBC),at appropriate concentrations,significantly promoted the proliferation,spreading,migration,and adhesion of human skin fibroblasts(HSFs),while inhibiting inflammation.In vivo diabeticmouse model,SePU/HBC exhibited a significant wound-healing effect,promoting re-epithelialization,collagen formation and maturation.Mechanistic studies revealed that SePU/HBC alleviated endoplasmic reticulum stress under hyperglycemic conditions by activating the UPR-related gene ATF6 to alleviate endoplasmic reticulum stress(ERS)and inhibit apoptosis.This study offers a novel strategy for diabetic wound treatment using SePU/HBC,which activates the UPR and inhibits apoptosis,demonstrating promising clinical applications for wound healing.展开更多
Bone marrow mesenchymal stromal/stem cells (MSCs) are a heterogeneous population that can self-renew and generate stroma,cartilage, fat, and bone. Although a significant progress has been made toward recognizing about...Bone marrow mesenchymal stromal/stem cells (MSCs) are a heterogeneous population that can self-renew and generate stroma,cartilage, fat, and bone. Although a significant progress has been made toward recognizing about the phenotypic characteristics ofMSCs, the true identity and properties of MSCs in bone marrow remain unclear. Here, we report the expression landscape of humanfetal BM nucleated cells (BMNCs) based on the single-cell transcriptomic analysis. Unexpectedly, while the common cell surfacemarkers such as CD146, CD271, and PDGFRa used for isolating MSCs were not detected, LIFR+PDGFRB+ were identified to bespecific markers of MSCs as the early progenitors. In vivo transplantation demonstrated that LIFR+PDGFRB+CD45-CD31-CD235a-MSCs could form bone tissues and reconstitute the hematopoietic microenvironment (HME) effectively in vivo. Interestingly, wealso identified a subpopulation of bone unipotent progenitor expressing TM4SF1+CD44+CD73+CD45-CD31-CD235a-, which hadosteogenic potentials, but could not reconstitute HME. MSCs expressed a set of different transcription factors at the different stagesof human fetal bone marrow, indicating that the stemness properties of MSCs might change during development. Moreover,transcriptional characteristics of cultured MSCs were significantly changed compared with freshly isolated primary MSCs. Ourcellular profiling provides a general landscape of heterogeneity, development, hierarchy, microenvironment of the human fetal BMderivedstem cells at single-cell resolution.展开更多
Understanding mechanisms underlying the heterogeneity of multipotent stem cells offers invaluable insights into biogenesis and tissue development. Extracellular matrix (ECM) stiffness has been acknowledged as a crucia...Understanding mechanisms underlying the heterogeneity of multipotent stem cells offers invaluable insights into biogenesis and tissue development. Extracellular matrix (ECM) stiffness has been acknowledged as a crucial factor regulating stem cell fate. However, how cells sense stiffness cues and adapt their metabolism activity is still unknown. Here we report the novel role of mitochondrial phosphoenolpyruvate carboxykinase (PCK2) in enhancing osteogenesis in 3D ECM via glycolysis. We experimentally mimicked the physical characteristics of 3D trabeculae network of normal and osteoporotic bone with different microstructure and stiffness, observing that PCK2 promotes osteogenesis in 3D ECM with tunable stiffness in vitro and in vivo. Mechanistically, PCK2 enhances the rate-limiting metabolic enzyme pallet isoform phosphofructokinase (PFKP) in 3D ECM, and further activates AKT/extracellular signal-regulated kinase 1/2 (ERK1/2) cascades, which directly regulates osteogenic differentiation of MSCs. Collectively, our findings implicate an intricate crosstalk between cell mechanics and metabolism, and provide new perspectives for strategies of osteoporosis.展开更多
Treatment of osteoporosis is still a challenge in clinic,which leads to an increasing social burden as the aging of population.Exosomes originated from human adipose-derived stem cells(hASCs)hold promise to promote os...Treatment of osteoporosis is still a challenge in clinic,which leads to an increasing social burden as the aging of population.Exosomes originated from human adipose-derived stem cells(hASCs)hold promise to promote osteogenic differentiation,thus may ameliorate osteoporosis.The main purpose of this study was to investigate the novel usage of hASC-derived exosomes in the treatment of osteoporosis and their underlying mechanism.Two types of exosomes,i.e.,exosomes derived from hASCs cultured in proliferation medium(P-Exos)and osteogenic induction medium(O-Exos),were obtained.As compared with P-Exos,O-Exos could promote the osteogenic differentiation of mouse bone marrow-derived stem cells(mBMSCs)from osteoporotic mice in vitro and ameliorated osteoporosis in vivo.Then,microRNA(miRNA)-335-3p was identified to be the key differentially expressed microRNA between the two exosomes by small RNA sequencing,gene overexpression and knock-down,qRT-PCR,and dual-luciferase reporter assay,and Aplnr was confirmed to be the potential target gene of miRNA-335-3p.In addition,miR335-3p inhibitor-optimized O-Exos were established by transfection of miR-335-3p inhibitor,which significantly enhanced the osteogenic differentiation of mBMSCs in vitro,and bone density and number of trabecular bones in vivo compared with unoptimized O-Exos.Our results indicated that the ASC-exosome-based therapy brings new possibilities for osteoporosis treatment.Besides,engineered exosomes based on transfection of miRNA are a promising strategy to optimize the therapeutic effect of exosomes on osteoporosis.展开更多
基金supported by grants from the National Natural Science Foundation of China(81200763 to WG and 81070809 to YZ)the Program for New Century Excellent Talents(NCET)at the University from Ministry of Education of China(NCET-11-0026)+1 种基金the PKU School of Stomatology for Talented Young Investigators(PKUSS20150107)the Construction Program for the National Key Clinical Specialty from the National Health and Family Planning Commission of China(2011)
文摘Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulation plays an important role in the developmental origins of osteoporosis; however, few studies have investigated the potential of epigenetic therapy to improve or rescue the osteogenic ability of bone marrow mesenchymal stem cells(BMMSCs) under osteoporotic conditions. Here, we investigated pargyline, an inhibitor of lysine-specific demethylase 1(LSD1), which mainly catalyzes the demethylation of the di- and mono-methylation of H3K4. We demonstrated that 1.5 mmol·Lpargyline was the optimal concentration for the osteogenic differentiation of human BMMSCs. Pargyline rescued the osteogenic differentiation ability of mouse BMMSCs under osteoporotic conditions by enhancing the dimethylation level of H3K4 at the promoter regions of osteogenesis-related genes. Moreover, pargyline partially rescued or prevented the osteoporotic conditions in aged or ovariectomized mouse models, respectively. By introducing the concept of epigenetic therapy into the field of osteoporosis, this study demonstrated that LSD1 inhibitors could improve the clinical practice of MSC-based bone tissue engineering and proposes their novel use to treat osteoporosis.
基金supported by the Beijing Natural Science Foundation(Grant Numbers 7232221 and L222030)the National Natural Science Foundation of China(Grant Number 82271032)+1 种基金the National Key R&D Program of China(Grant Number 2023YFA0915300)the XPLORER PRIZE and the Beijing Outstanding Young Scientist Program.
文摘Diabetic wound healing impairment,a common complication of diabetes,has limited clinical treatment options and poor therapeutic outcomes,causing significant physical pain and psychological burden for patients.This study aims to accelerate wound healing by modulating cellular stress responses,offering a safe and efficient new therapeutic strategy.Herein,a seleniumcontaining polyurethane(SePU)thermo-sensitive hydrogel was synthesized,and its mechanism for promoting diabetic wound healing by activating the unfolded protein response(UPR)was elucidated.Hydroxybutyl chitosan(HBC)offers amore convenient application for SePU,with its high hydroxybutyl substitution enabling the hydrogel to undergo a rapid sol-gel transition at physiological temperatures.In vitro experiments showed that SePU thermo-sensitive hydrogel(SePU/HBC),at appropriate concentrations,significantly promoted the proliferation,spreading,migration,and adhesion of human skin fibroblasts(HSFs),while inhibiting inflammation.In vivo diabeticmouse model,SePU/HBC exhibited a significant wound-healing effect,promoting re-epithelialization,collagen formation and maturation.Mechanistic studies revealed that SePU/HBC alleviated endoplasmic reticulum stress under hyperglycemic conditions by activating the UPR-related gene ATF6 to alleviate endoplasmic reticulum stress(ERS)and inhibit apoptosis.This study offers a novel strategy for diabetic wound treatment using SePU/HBC,which activates the UPR and inhibits apoptosis,demonstrating promising clinical applications for wound healing.
基金the National Natural Science Foundation of China(81930026 and 81970911)the National Key R&D Program of China(2017YFA0102702 and 2018YFA0107601)the Beijing Municipal Science&Technology Commission(Z181100001318001).
文摘Bone marrow mesenchymal stromal/stem cells (MSCs) are a heterogeneous population that can self-renew and generate stroma,cartilage, fat, and bone. Although a significant progress has been made toward recognizing about the phenotypic characteristics ofMSCs, the true identity and properties of MSCs in bone marrow remain unclear. Here, we report the expression landscape of humanfetal BM nucleated cells (BMNCs) based on the single-cell transcriptomic analysis. Unexpectedly, while the common cell surfacemarkers such as CD146, CD271, and PDGFRa used for isolating MSCs were not detected, LIFR+PDGFRB+ were identified to bespecific markers of MSCs as the early progenitors. In vivo transplantation demonstrated that LIFR+PDGFRB+CD45-CD31-CD235a-MSCs could form bone tissues and reconstitute the hematopoietic microenvironment (HME) effectively in vivo. Interestingly, wealso identified a subpopulation of bone unipotent progenitor expressing TM4SF1+CD44+CD73+CD45-CD31-CD235a-, which hadosteogenic potentials, but could not reconstitute HME. MSCs expressed a set of different transcription factors at the different stagesof human fetal bone marrow, indicating that the stemness properties of MSCs might change during development. Moreover,transcriptional characteristics of cultured MSCs were significantly changed compared with freshly isolated primary MSCs. Ourcellular profiling provides a general landscape of heterogeneity, development, hierarchy, microenvironment of the human fetal BMderivedstem cells at single-cell resolution.
基金National Natural Science Foundation of China(81870742,81970911)Beijing Natural Science Foundation(7202233)+2 种基金Key Project of the National Natural Science Foundation of China(81930026)Project funded by China Postdoctoral Science Foundation(2020TQ0020,2021M700280)Research Foundation of Peking University School and Hospital of Stomatology(PKUSS20210102).We thank Dr.Siying Qin at the National Center for Protein Science at Peking University for technical assistance in AFM operation and data analysis,Dr.Yiqun Liu and Pengyuan Dong at the National Center for Protein Science and Core Facilities of Life Sciences in Peking University for technical assistance in SEM sample preparation,operation,and Xiaorui Hao at Electron Microscopy Laboratory at Peking University for bone sample preparation for AFM measurements.The image acquisition of confocal microscope was supported by Biological Imaging and Analysis Laboratory,Medical and Health Analytical Center,Peking University,especially Jing Wu.We appreciate Rong Guo of Beijing Cnkingbio Biotechnology Co.LTD for the bioinformatics assistance.
文摘Understanding mechanisms underlying the heterogeneity of multipotent stem cells offers invaluable insights into biogenesis and tissue development. Extracellular matrix (ECM) stiffness has been acknowledged as a crucial factor regulating stem cell fate. However, how cells sense stiffness cues and adapt their metabolism activity is still unknown. Here we report the novel role of mitochondrial phosphoenolpyruvate carboxykinase (PCK2) in enhancing osteogenesis in 3D ECM via glycolysis. We experimentally mimicked the physical characteristics of 3D trabeculae network of normal and osteoporotic bone with different microstructure and stiffness, observing that PCK2 promotes osteogenesis in 3D ECM with tunable stiffness in vitro and in vivo. Mechanistically, PCK2 enhances the rate-limiting metabolic enzyme pallet isoform phosphofructokinase (PFKP) in 3D ECM, and further activates AKT/extracellular signal-regulated kinase 1/2 (ERK1/2) cascades, which directly regulates osteogenic differentiation of MSCs. Collectively, our findings implicate an intricate crosstalk between cell mechanics and metabolism, and provide new perspectives for strategies of osteoporosis.
基金supported by grants from the National Natural Science Foundation of China(Nos.81900971 and 81930026)Beijing Natural Science Foundation(No.7192228)the Young Elite Scientist Sponsorship Program by CAST(No.2015QNRC001)。
文摘Treatment of osteoporosis is still a challenge in clinic,which leads to an increasing social burden as the aging of population.Exosomes originated from human adipose-derived stem cells(hASCs)hold promise to promote osteogenic differentiation,thus may ameliorate osteoporosis.The main purpose of this study was to investigate the novel usage of hASC-derived exosomes in the treatment of osteoporosis and their underlying mechanism.Two types of exosomes,i.e.,exosomes derived from hASCs cultured in proliferation medium(P-Exos)and osteogenic induction medium(O-Exos),were obtained.As compared with P-Exos,O-Exos could promote the osteogenic differentiation of mouse bone marrow-derived stem cells(mBMSCs)from osteoporotic mice in vitro and ameliorated osteoporosis in vivo.Then,microRNA(miRNA)-335-3p was identified to be the key differentially expressed microRNA between the two exosomes by small RNA sequencing,gene overexpression and knock-down,qRT-PCR,and dual-luciferase reporter assay,and Aplnr was confirmed to be the potential target gene of miRNA-335-3p.In addition,miR335-3p inhibitor-optimized O-Exos were established by transfection of miR-335-3p inhibitor,which significantly enhanced the osteogenic differentiation of mBMSCs in vitro,and bone density and number of trabecular bones in vivo compared with unoptimized O-Exos.Our results indicated that the ASC-exosome-based therapy brings new possibilities for osteoporosis treatment.Besides,engineered exosomes based on transfection of miRNA are a promising strategy to optimize the therapeutic effect of exosomes on osteoporosis.
