How osteoblast cells are induced is a central question for understanding skeletal formation. Abnormal osteoblast differentiation leads to a broad range of devastating craniofacial diseases. Here we have investigated i...How osteoblast cells are induced is a central question for understanding skeletal formation. Abnormal osteoblast differentiation leads to a broad range of devastating craniofacial diseases. Here we have investigated intramembranous ossification during cranial bone development in mouse models of skeletal genetic diseases that exhibit craniofacial bone defects. The GNAS gene encodes Gαs that transduces GPCR signaling. GNAS activation or loss-of-function mutations in humans cause fibrous dysplasia(FD) or progressive osseous heteroplasia(POH) that shows craniofacial hyperostosis or craniosynostosis, respectively. We find here that, while Hh ligand-dependent Hh signaling is essential for endochondral ossification, it is dispensable for intramembranous ossification, where Gαsregulates Hh signaling in a ligand-independent manner. We further show that Gαscontrols intramembranous ossification by regulating both Hh and Wnt/β-catenin signaling. In addition, Gαsactivation in the developing cranial bone leads to reduced ossification but increased cartilage presence due to reduced cartilage dissolution, not cell fate switch. Small molecule inhibitors of Hh and Wnt signaling can effectively ameliorate cranial bone phenotypes in mice caused by loss or gain of Gnas function mutations, respectively. Our work shows that studies of genetic diseases provide invaluable insights in both pathological bone defects and normal bone development, understanding both leads to better diagnosis and therapeutic treatment of bone diseases.展开更多
Tissue-resident stem cells are essential for development and repair,and in the skeleton,this function is fulfilled by recently identified skeletal stem cells(SSCs).However,recent work has identified that SSCs are not ...Tissue-resident stem cells are essential for development and repair,and in the skeleton,this function is fulfilled by recently identified skeletal stem cells(SSCs).However,recent work has identified that SSCs are not monolithic,with long bones,craniofacial sites,and the spine being formed by distinct stem cells.Recent studies have utilized techniques such as fluorescence-activated cell sorting,lineage tracing,and single-cell sequencing to investigate the involvement of ssCs in bone development,homeostasis,and disease.These investigations have allowed researchers to map the lineage commitment trajectory of ssCs in different parts of the body and at different time points.Furthermore,recent studies have shed light on the characteristics of ssCs in both physiological and pathological conditions.This review focuses on discussing the spatiotemporal distribution of ssCs and enhancing our understanding of the diversity and plasticity of ssCs by summarizing recent discoveries.展开更多
目的观察解聚素样金属蛋白酶10(A disintegrin and metalloprotease 10,ADAM10)在小鼠颅面部骨骼膜发育过程中的表达变化。方法以野生型C57BL/6小鼠为实验对象,阿辛蓝-茜素红染色显示小鼠膜内成骨区域,结合免疫组织荧光,检测ADAM10在骨...目的观察解聚素样金属蛋白酶10(A disintegrin and metalloprotease 10,ADAM10)在小鼠颅面部骨骼膜发育过程中的表达变化。方法以野生型C57BL/6小鼠为实验对象,阿辛蓝-茜素红染色显示小鼠膜内成骨区域,结合免疫组织荧光,检测ADAM10在骨组织中的表达。三标免疫荧光观察ADAM10在MC3T3细胞系中亚细胞定位。蛋白免疫印迹检测ADAM10在小鼠出生前后的表达量变化。结果组织阿辛蓝茜素红染色显示小鼠前颅骨、鼻旁软骨、上颌骨、腭板和下颌骨成骨活跃,并结合免疫组织荧光检测,发现ADAM10在小鼠前颌骨、鼻旁软骨、上颌骨、腭板和下颌骨广泛表达,且主要表达在成骨活跃的区域。MC3T3细胞三标免疫荧光检测进一步定位ADAM10广泛分布在胞浆中,在质膜和细胞核附近表达高;其胞核附近的高表达信号与高尔基体共标,提示其可能在高尔基体中加工后至细胞膜发挥功能。同时,蛋白免疫印迹结果证实,ADAM10在小鼠出生前后表达高,成年后表达明显降低。结论 ADAM10广泛表达于小鼠早期颅面部膜内成骨活跃区域,提示其可能调控小鼠颅面部膜内成骨过程。展开更多
基金supported by the NIH grants R01DE025866 from NIDCRR01AR070877 from NIAMSsupported by the 111 Project, MOE (B14038), China
文摘How osteoblast cells are induced is a central question for understanding skeletal formation. Abnormal osteoblast differentiation leads to a broad range of devastating craniofacial diseases. Here we have investigated intramembranous ossification during cranial bone development in mouse models of skeletal genetic diseases that exhibit craniofacial bone defects. The GNAS gene encodes Gαs that transduces GPCR signaling. GNAS activation or loss-of-function mutations in humans cause fibrous dysplasia(FD) or progressive osseous heteroplasia(POH) that shows craniofacial hyperostosis or craniosynostosis, respectively. We find here that, while Hh ligand-dependent Hh signaling is essential for endochondral ossification, it is dispensable for intramembranous ossification, where Gαsregulates Hh signaling in a ligand-independent manner. We further show that Gαscontrols intramembranous ossification by regulating both Hh and Wnt/β-catenin signaling. In addition, Gαsactivation in the developing cranial bone leads to reduced ossification but increased cartilage presence due to reduced cartilage dissolution, not cell fate switch. Small molecule inhibitors of Hh and Wnt signaling can effectively ameliorate cranial bone phenotypes in mice caused by loss or gain of Gnas function mutations, respectively. Our work shows that studies of genetic diseases provide invaluable insights in both pathological bone defects and normal bone development, understanding both leads to better diagnosis and therapeutic treatment of bone diseases.
基金supported in part by National Natural Science Foundation of China(Grant nos.82372362,81972034,92068104 to Ren Xu and 82002262 to Na Li)National Key R&D Program of China(2020YFA0112900 to Ren Xu)+2 种基金Natural Science Foundation of Fujian Province(2022J06003 to Ren Xu)Project of Xiarmen Cell Therapy Research,Xiamen,Fujian,China(3502Z20214001)supported by a Pershing Square MIND Prize award,an Irma T.Hirschl Career Scientist Award,an NIH award RO1AR075585,a Career Award for Medical Scientists from the Burroughs Welcome Foundation,a William Rhodes and Louise Tilzer-Rhodes Center for Glioblastoma research award,and a Weill Comell Medicine Prostate Cancer SPORE Developmental Research Program Award。
文摘Tissue-resident stem cells are essential for development and repair,and in the skeleton,this function is fulfilled by recently identified skeletal stem cells(SSCs).However,recent work has identified that SSCs are not monolithic,with long bones,craniofacial sites,and the spine being formed by distinct stem cells.Recent studies have utilized techniques such as fluorescence-activated cell sorting,lineage tracing,and single-cell sequencing to investigate the involvement of ssCs in bone development,homeostasis,and disease.These investigations have allowed researchers to map the lineage commitment trajectory of ssCs in different parts of the body and at different time points.Furthermore,recent studies have shed light on the characteristics of ssCs in both physiological and pathological conditions.This review focuses on discussing the spatiotemporal distribution of ssCs and enhancing our understanding of the diversity and plasticity of ssCs by summarizing recent discoveries.
