Epithelial-mesenchymal transition （EMT） is initially considered as a physiological phenomenon during the embryogenesis of mammals, as well as a basic biological event maintaining the stability of the vital body. Rec...Epithelial-mesenchymal transition （EMT） is initially considered as a physiological phenomenon during the embryogenesis of mammals, as well as a basic biological event maintaining the stability of the vital body. Recent researches indicated that EMT plays a critical role in various tumors progression, through which epithelial cancers invade and metastasize. The cell characteristics are changed during EMT, in which the cells lose cell-cell and cell-matrix interactions and apical polarity, reorganize their cytoskeleton, and become isolated, motile, as well as resistant to anoikis, then become spindle-shaped mesenchymal cells. This review lays emphasis on studying the cell morphogenesis, makers and molecular mechanism regulation about EMT, discussing the relationship between the EMT and the cancer development and metastasis.展开更多
Mammalian tooth development is largely dependent on sequential and reciprocal epithelial-mesenchymal interactions. These processes involve a series of inductive and permissive interactions that result in the determina...Mammalian tooth development is largely dependent on sequential and reciprocal epithelial-mesenchymal interactions. These processes involve a series of inductive and permissive interactions that result in the determination, differentiation, and organization of odontogenic tissues. Multiple signaling molecules, including BMPs, FGFs, Shh, and Wnt proteins, have been implicated in mediating these tissue interactions. Transcription factors participate in epithelial-mesenchymal interactions via linking the signaling loops between tissue layers by responding to inductive signals and regulating the expression of other signaling molecules. Adult stem cells are highly plastic and multipotent. These cells including dental pulp stem cells and bone marrow stromal cells could be reprogrammed into odontogenic fate and participated in tooth formation. Recent progress in the studies of molecular basis of tooth development, adult stem cell biology, and regene- ration will provide fundamental knowledge for the realization of human tooth regeneration in the near future.展开更多
A wide variety of neurons and gIial cells differentiatefrom common precursor cells in the developing nervoussystem. During this process, Notch-mediated cell-cell in-teraction is essential for maintenance of dividing c...A wide variety of neurons and gIial cells differentiatefrom common precursor cells in the developing nervoussystem. During this process, Notch-mediated cell-cell in-teraction is essential for maintenance of dividing cells andsubsequellt generation of cell type diversity. Activation ofNotch inhibits cellular differentiation, and abnormality ofthe Notch pathway leads to premature neuronal differenti-ation, the lack of some cell types, and severe defects of tis-sue morphogenesis. Recent data demonstrate that Notchfails to inhibit cellular differentiation in the absence of thebHLH genes Hes1 and He5, which functionally afitago-nize the neuronal bHLH genes such as theh1- These re-sults indicate that the two Hes genes are essential effecorsfor the Notch pathway and that neuronal differentiation iscontrolled by the pathway "Notch-+He1/Hs5,Mish1".展开更多
MicroRNAs （miRNAs）, approximately 21 to 23 nucleotides （nt） in length, belong to a set of smal non-coding RNA molecules that were not thought to be functional until the recent decades. miRNAs play important roles ...MicroRNAs （miRNAs）, approximately 21 to 23 nucleotides （nt） in length, belong to a set of smal non-coding RNA molecules that were not thought to be functional until the recent decades. miRNAs play important roles in many diseases such as various kinds of cancers and immune disorders. Many studies have focused on the relationship between miRNAs and diseases. miRNAs are significant mediators in human growth and development and in the genesis and development of diseases. Almost 30% of the activity of protein-coding genes is forecasted to be regulated by miRNAs in mammals, and some miRNAs are regarded as potential therapeutic targets for various diseases. In this review, we outline some functions of miRNAs, especialy those related to diseases.展开更多
Neurons synthesizing the neurotransmitter dopamine exert crucial functions in the mammalian brain. The biggest and most important population of dopamine-synthesizing neurons is located in the mammalian ventral midbra...Neurons synthesizing the neurotransmitter dopamine exert crucial functions in the mammalian brain. The biggest and most important population of dopamine-synthesizing neurons is located in the mammalian ventral midbrain （VM）, and controls and modulates the exe- cution of motor, cognitive, affective, motivational, and rewarding behaviours. Degeneration of these neurons leads to motor deficits that are characteristic of Parkinson＇s disease, while their dysfunction is involved in the pathogenesis of psychiatric disorders including schizophrenia and addiction. Because the aetiology and therapeutic prospects for these diseases include neurodevelopmental aspects, substantial scientific interest has been focused on deciphering the mechanistic pathways that control the generation and sur- vival of these neurons during embryonic development. Researches during the last decade revealed the pivotal role of the secreted Wntl ligand and its signaUing cascade in the generation of the dopamine-synthesizing neurons in the mammalian VM. Here, we summarize the initial and more recent findings that have unravelled several Wntl-controUed genetic networks required for the proliferation and commitment of VM progenitors to the dopaminergic cell fate during midgestational embryonic stages, and for the correct differentiation of these progenitors into postmitotic dopamine-synthesizing neurons at late midgestational embryonic and foetal stages.展开更多
Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size an...Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size and pup weight. We exposed the hybrid juvenile offspring of field-caught and lab-descended house mice Mus musculus to the chemical cues of mouse-fed or chick-fed kingsnakes, Lampropeltis getula, for 20 days after weaning, to examine the effects of ophidian predator cues on prey development. We hypothesized that these cues would elicit inducible defenses such as alteration of growth rates, and/or the timing of reproductive development in mice. Once mature, the reproductive effort of the mice might also be impacted by producing smaller litter sizes or lighter pups or not reproducing at all. We found no effect of kingsnake cues on any of the measures. These findings support the hypothesis that inducible defenses may have evolved as a strategy to deal with specific predators.展开更多
基金Supported by the grants from the Natural Science Foundation of China （No. 81000998） Natural Science Foundation of Hubei Province of China （No. 2007ABA248）
文摘Epithelial-mesenchymal transition （EMT） is initially considered as a physiological phenomenon during the embryogenesis of mammals, as well as a basic biological event maintaining the stability of the vital body. Recent researches indicated that EMT plays a critical role in various tumors progression, through which epithelial cancers invade and metastasize. The cell characteristics are changed during EMT, in which the cells lose cell-cell and cell-matrix interactions and apical polarity, reorganize their cytoskeleton, and become isolated, motile, as well as resistant to anoikis, then become spindle-shaped mesenchymal cells. This review lays emphasis on studying the cell morphogenesis, makers and molecular mechanism regulation about EMT, discussing the relationship between the EMT and the cancer development and metastasis.
基金The studies described here from the authors'laborato-ries were supported by grants from the NIH,NSF,and Louisiana Board of Regents to Yi Ping CHEN,and Na-tional Natural Science Foundation of China(No.30270652)Fujian Provincial Department of Science and Technology(No.2002I006),China to Yan Ding ZHANG.
文摘Mammalian tooth development is largely dependent on sequential and reciprocal epithelial-mesenchymal interactions. These processes involve a series of inductive and permissive interactions that result in the determination, differentiation, and organization of odontogenic tissues. Multiple signaling molecules, including BMPs, FGFs, Shh, and Wnt proteins, have been implicated in mediating these tissue interactions. Transcription factors participate in epithelial-mesenchymal interactions via linking the signaling loops between tissue layers by responding to inductive signals and regulating the expression of other signaling molecules. Adult stem cells are highly plastic and multipotent. These cells including dental pulp stem cells and bone marrow stromal cells could be reprogrammed into odontogenic fate and participated in tooth formation. Recent progress in the studies of molecular basis of tooth development, adult stem cell biology, and regene- ration will provide fundamental knowledge for the realization of human tooth regeneration in the near future.
文摘A wide variety of neurons and gIial cells differentiatefrom common precursor cells in the developing nervoussystem. During this process, Notch-mediated cell-cell in-teraction is essential for maintenance of dividing cells andsubsequellt generation of cell type diversity. Activation ofNotch inhibits cellular differentiation, and abnormality ofthe Notch pathway leads to premature neuronal differenti-ation, the lack of some cell types, and severe defects of tis-sue morphogenesis. Recent data demonstrate that Notchfails to inhibit cellular differentiation in the absence of thebHLH genes Hes1 and He5, which functionally afitago-nize the neuronal bHLH genes such as theh1- These re-sults indicate that the two Hes genes are essential effecorsfor the Notch pathway and that neuronal differentiation iscontrolled by the pathway "Notch-+He1/Hs5,Mish1".
基金Supported by a grant from the Natural Science Foundation of Hebei Province(No.C2009001151)
文摘MicroRNAs （miRNAs）, approximately 21 to 23 nucleotides （nt） in length, belong to a set of smal non-coding RNA molecules that were not thought to be functional until the recent decades. miRNAs play important roles in many diseases such as various kinds of cancers and immune disorders. Many studies have focused on the relationship between miRNAs and diseases. miRNAs are significant mediators in human growth and development and in the genesis and development of diseases. Almost 30% of the activity of protein-coding genes is forecasted to be regulated by miRNAs in mammals, and some miRNAs are regarded as potential therapeutic targets for various diseases. In this review, we outline some functions of miRNAs, especialy those related to diseases.
文摘Neurons synthesizing the neurotransmitter dopamine exert crucial functions in the mammalian brain. The biggest and most important population of dopamine-synthesizing neurons is located in the mammalian ventral midbrain （VM）, and controls and modulates the exe- cution of motor, cognitive, affective, motivational, and rewarding behaviours. Degeneration of these neurons leads to motor deficits that are characteristic of Parkinson＇s disease, while their dysfunction is involved in the pathogenesis of psychiatric disorders including schizophrenia and addiction. Because the aetiology and therapeutic prospects for these diseases include neurodevelopmental aspects, substantial scientific interest has been focused on deciphering the mechanistic pathways that control the generation and sur- vival of these neurons during embryonic development. Researches during the last decade revealed the pivotal role of the secreted Wntl ligand and its signaUing cascade in the generation of the dopamine-synthesizing neurons in the mammalian VM. Here, we summarize the initial and more recent findings that have unravelled several Wntl-controUed genetic networks required for the proliferation and commitment of VM progenitors to the dopaminergic cell fate during midgestational embryonic stages, and for the correct differentiation of these progenitors into postmitotic dopamine-synthesizing neurons at late midgestational embryonic and foetal stages.
文摘Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size and pup weight. We exposed the hybrid juvenile offspring of field-caught and lab-descended house mice Mus musculus to the chemical cues of mouse-fed or chick-fed kingsnakes, Lampropeltis getula, for 20 days after weaning, to examine the effects of ophidian predator cues on prey development. We hypothesized that these cues would elicit inducible defenses such as alteration of growth rates, and/or the timing of reproductive development in mice. Once mature, the reproductive effort of the mice might also be impacted by producing smaller litter sizes or lighter pups or not reproducing at all. We found no effect of kingsnake cues on any of the measures. These findings support the hypothesis that inducible defenses may have evolved as a strategy to deal with specific predators.
