Ontology as an important representation model of semantic web has valuable application. A new ontology model on the basis of Computer Graphics (CG) knowledge is proposed, called CG ontology model. The protégé...Ontology as an important representation model of semantic web has valuable application. A new ontology model on the basis of Computer Graphics (CG) knowledge is proposed, called CG ontology model. The protégé is used to build this ontology model conveniently. The Jena API is applied to store CG owl documents in MySQL, set inference rule and achieve search queries on the ontology database. Finally, the Jena-based ontology model retrieval system is developed.展开更多
Body weight regain often causes failure of obesity therapies while the underlying mechanism remains largely unknown.In this study,we report that immune cells,especially CD4+T cells,mediate the‘memory’of previous obe...Body weight regain often causes failure of obesity therapies while the underlying mechanism remains largely unknown.In this study,we report that immune cells,especially CD4+T cells,mediate the‘memory’of previous obese status.In a weight gain-loss-regain model,we found that C57BL/6J mice with an obesity history showed a much faster rate of body weight regain.This obesity memory could last for at least 2 months after previously obese mice were kept at the same body weight as non-obese mice.Surprisingly,such obesity memory was abrogated by dexamethasone treatment,whereas immunodeficient Rag1−/−and H2A−/−mice failed to establish such memory.Rag1−/−mice repossessed the obesity memory when immune cells or CD4+T cells isolated from previously obese mice were transferred.Furthermore,depletion of CD4+T cells led to obesity memory ablation.Taken together,we conclude that CD4+T cells mediate obesity memory and promote weight regain.展开更多
Double-positive(DP)thymocytes undergo positive selection to become mature single-positive CD4+and CD8+T cells in response to T cell receptor(TCR)signaling.Unlike mature T cells,DP cells must respond to low-affinity se...Double-positive(DP)thymocytes undergo positive selection to become mature single-positive CD4+and CD8+T cells in response to T cell receptor(TCR)signaling.Unlike mature T cells,DP cells must respond to low-affinity self-peptide-MHC ligands before full upregulation of their surface TCR expression can occur.Thus,DP thymocytes must be more sensitive to ligands than mature T cells.A number of molecules have been found that are able to enhance the strength of the TCR signal to facilitate positive selection.However,almost all of these molecules are also active in mature T cells.Themis(thymocyte expressed molecule involved in selection)and Tespa1(thymocyte expressed positive selection associated 1)are two recently discovered molecules essential for optimal TCR signaling and thymocyte development.A deficiency in both molecules leads to defects in positive selection.Here,we compared the relative contributions of Themis and Tespa1 to positive selection in thymocytes.We show that Tespa1 deficiency led to more limited and specific gene expression profile changes in cells undergoing positive selection.In mixed bone marrow transfer experiments,Tespa1^(−/−)cells showed more severe defects in thymocyte development than Themis^(−/−)cells.However,Tespa1^(−/−)cells showed a substantial degree of homeostatic expansion and became predominant in the peripheral lymphoid organs,suggesting that Tespa1 is a thymic-specific TCR signaling regulator.This hypothesis is further supported by our observations in Tespa1 conditional knockout mice,as Tespa1 deletion in peripheral T cells did not affect TCR signaling or cell proliferation.The different regulatory effects of Tespa1 and Themis are in accordance with their nonredundant roles in thymocyte selection,during which Tespa1 and Themis double knockouts showed additive defects.展开更多
文摘Ontology as an important representation model of semantic web has valuable application. A new ontology model on the basis of Computer Graphics (CG) knowledge is proposed, called CG ontology model. The protégé is used to build this ontology model conveniently. The Jena API is applied to store CG owl documents in MySQL, set inference rule and achieve search queries on the ontology database. Finally, the Jena-based ontology model retrieval system is developed.
基金This work was supported by the National Natural Science Foundation of China(Grant 31301217)the Ministry of Science and Technology of China(Grants 2015BAI08B02 and 2014BAI02B01).
文摘Body weight regain often causes failure of obesity therapies while the underlying mechanism remains largely unknown.In this study,we report that immune cells,especially CD4+T cells,mediate the‘memory’of previous obese status.In a weight gain-loss-regain model,we found that C57BL/6J mice with an obesity history showed a much faster rate of body weight regain.This obesity memory could last for at least 2 months after previously obese mice were kept at the same body weight as non-obese mice.Surprisingly,such obesity memory was abrogated by dexamethasone treatment,whereas immunodeficient Rag1−/−and H2A−/−mice failed to establish such memory.Rag1−/−mice repossessed the obesity memory when immune cells or CD4+T cells isolated from previously obese mice were transferred.Furthermore,depletion of CD4+T cells led to obesity memory ablation.Taken together,we conclude that CD4+T cells mediate obesity memory and promote weight regain.
基金supported by grants from the National Natural Science Foundation of China(31530019,31770954,and 31325009 to L.L.)the National Key R&D Program of China(2018YFC1105102)the Fundamental Research Funds for the Central Universities(2018XZZX001-12).
文摘Double-positive(DP)thymocytes undergo positive selection to become mature single-positive CD4+and CD8+T cells in response to T cell receptor(TCR)signaling.Unlike mature T cells,DP cells must respond to low-affinity self-peptide-MHC ligands before full upregulation of their surface TCR expression can occur.Thus,DP thymocytes must be more sensitive to ligands than mature T cells.A number of molecules have been found that are able to enhance the strength of the TCR signal to facilitate positive selection.However,almost all of these molecules are also active in mature T cells.Themis(thymocyte expressed molecule involved in selection)and Tespa1(thymocyte expressed positive selection associated 1)are two recently discovered molecules essential for optimal TCR signaling and thymocyte development.A deficiency in both molecules leads to defects in positive selection.Here,we compared the relative contributions of Themis and Tespa1 to positive selection in thymocytes.We show that Tespa1 deficiency led to more limited and specific gene expression profile changes in cells undergoing positive selection.In mixed bone marrow transfer experiments,Tespa1^(−/−)cells showed more severe defects in thymocyte development than Themis^(−/−)cells.However,Tespa1^(−/−)cells showed a substantial degree of homeostatic expansion and became predominant in the peripheral lymphoid organs,suggesting that Tespa1 is a thymic-specific TCR signaling regulator.This hypothesis is further supported by our observations in Tespa1 conditional knockout mice,as Tespa1 deletion in peripheral T cells did not affect TCR signaling or cell proliferation.The different regulatory effects of Tespa1 and Themis are in accordance with their nonredundant roles in thymocyte selection,during which Tespa1 and Themis double knockouts showed additive defects.
