Objective:To determine the effect of an immunosuppressive active component (periploside A) isolated from the stem bark of Periplocae Cortex (Periploca sepium Bge.),a Chinese medicinal herb used in the treatment of rhe...Objective:To determine the effect of an immunosuppressive active component (periploside A) isolated from the stem bark of Periplocae Cortex (Periploca sepium Bge.),a Chinese medicinal herb used in the treatment of rheumatoid arthritis for centuries in China,on positive selection of thymocytes in vitro.Methods:Female C57BL/6 mice at 6 weeks of age were housed in specific pathogen-free conditions.Double-positive thymocytes from C57BL/6 mice were induced into positive selection in vitro with or without periploside A treatment.Cell viability and expression of CD69,CD4,and CD8 were analyzed by flow cytometry.Results:Flow cytometric examination of thymocyte populations revealed that the percentage of CD8+ single-positive thymocytes was decreased by periploside A upon differentiation induced by an anti-CD3 antibody.However,the percentage of CD4+ single-positive thymocytes was decreased by periploside A upon differentiation induced by phorbol 12-myristate 13-acetate/ionomycin.Expression of CD69 plays a major role in prohibiting differentiation of thymocytes.Treatment with periploside A decreased CD69 expression in thymocytes.Conclusion:These results demonstrate that periploside A influences positive selection of thymocytes in vitro.展开更多
Murine CD4+CD8- (CD4SP) thymocyte subset is a heterogeneous population, in which the Qa-2- cells are less functional, whereas the Qa-2+ cells are fully functional. Evidence is provided here that the transition from Qa...Murine CD4+CD8- (CD4SP) thymocyte subset is a heterogeneous population, in which the Qa-2- cells are less functional, whereas the Qa-2+ cells are fully functional. Evidence is provided here that the transition from Qa-2- to Qa-2+ CD4SP thymocytes is an intrathymic process of differentiation induced by thymic medullary-type epithelial cells. The separated Qa-2-CD4SP could be induced to express Qa-2 molecules up to 84%- 89% of the total viable celb after cocultured for 3d with MTEC1 cells, a murine thymic medullary type epithelial cell line established in our laboratory. Kinetic study showed that both the percentage of Qa-2+ cells and the density of the expressed Qa-2 molecules on CD4SP thymocytes induced by MTEC1 were progressively increasing in 72-h cultures. The MTECl-induced Qa-2+CD4SP thymocytes were fully functional, which exhibited capabilities of proliferation and cytokine secretion in response to Con A stimulation as high as those of freshly isolated Qa-2+CD4SP thymocytes. The profile of展开更多
Using terminal deoxynucleotide transferase mediated dUTP digoxigenin nick end labeling (TUNEL) assay and propidium iodide DNA staining flow cytometry assay, the effects of mouse thymic dendritic cells (MTSC4) on the p...Using terminal deoxynucleotide transferase mediated dUTP digoxigenin nick end labeling (TUNEL) assay and propidium iodide DNA staining flow cytometry assay, the effects of mouse thymic dendritic cells (MTSC4) on the process of programmed cell death of thymocytes in vitro were investigated. It was noticed that thymocytes bound to MTSC4 used in this study. That the percentages of apoptotic nuclei of the bound thymocytes on MTSC4 were much higher than those of medium cultured thymocytes, while the bound thymocytes on mouse thymic epithelial cell (MTEC1) showed much lower percentages of apoptosis. FACS analysis quantitatively confirmed the observation. Phenotype analysis showed that MTSC4 induced the deletion of CD4+CD8+ cells and CD4+CD8 cells in 18 h of coculture. The results suggest that the negative selection of medullary thymocytes may be achieved by thymic dendritic cells through their enhancing effects on apoptosis.展开更多
Phenotypic analysis of the medullary-type CD4 CD8+ (CD8SP) thymocytes has revealed phenotypic heterogeneity within this cell population. The phenotype of mature peripheral CD8+T cells is TCRαβ+CD3+Qa-2+HSA3G11 6C10 ...Phenotypic analysis of the medullary-type CD4 CD8+ (CD8SP) thymocytes has revealed phenotypic heterogeneity within this cell population. The phenotype of mature peripheral CD8+T cells is TCRαβ+CD3+Qa-2+HSA3G11 6C10 , whereas in the medullary-type CD8SP thymocytes, 20% are Qa-2+; 33%, HAS ; 30%, 3G11 ; and 70% are 6C10 . The disparate expression patterns of these four cell surface markers suggest that medullary-type CD8SP thymocytes may undergo phenotypic maturation process. According to the distribution of these four celi surface markers, six subgroups of CD8SP thymocytes have been identified. The precursor-progeny relationship along with developmental pathway is postulated as follows: 6C10+HSA+3G11 Qa-2 - 6C10+HSA+ 3G11+Qa-2 6C10 HSA+3G11+Qa-2 -6C10 HSA 3G11 +Qa-2 -6C10 HSA 3G11 Qa-2 -6C10 HA S 3G11 Qa-2+, the cells inthe last subgroup exit the thymus and home into periphery.展开更多
The presence of a relatively mature CD4 <sup>+</sup> CD8<sup>-</sup> （SP） T cell subset in mouse thymus has been demonstrated. Composing of 10% of total CD4SP thymocytes, this subset is defin...The presence of a relatively mature CD4 <sup>+</sup> CD8<sup>-</sup> （SP） T cell subset in mouse thymus has been demonstrated. Composing of 10% of total CD4SP thymocytes, this subset is defined by the absence of 3G11 and 6C10 expression with a phenotype of CD69<sup>+/-</sup>, HSA<sup>med/lo</sup> and heterogeneous for Qa-2 expression. The proliferation capability of TCRαβ<sup>+</sup> 3G11<sup>-</sup> 6C10<sup>-</sup> CD4<sup>+</sup> CD8<sup>-</sup> thymocytes was high while using Con A stimulus. And Con A stimulation could result in secretion of IL-4, IL-10, IL-6 and a little amount of IFNγ. IL-2 was barely detectable. This is distinct from typical Th0 type cytokines. The cells of this subset were NK1.1 negative, but strongly expressed GATA-3 mRNA. The results suggest that the CD4<sup>+</sup> subset of 3G11<sup>-</sup> 6C10<sup>-</sup> NK1.1<sup>-</sup> phenotype possesses immunocompetent cells with functions characteristic of Th2-like cytokines, which may indicate the cells at transitional status from Th0 to Th2, with a propensity to Th2.展开更多
PF18-3 monoclonal antibody (mAb), one of the rat mAbs against mouse thymic stromal cells (MTSC), has been found to inhibit thymocyte apoptosis induced by a mouse thymic dendritic cell line, MTSC4, in previous co-cultu...PF18-3 monoclonal antibody (mAb), one of the rat mAbs against mouse thymic stromal cells (MTSC), has been found to inhibit thymocyte apoptosis induced by a mouse thymic dendritic cell line, MTSC4, in previous co-culture study. The aim of this research is to investigate the character of PF18-3 mAb recognized molecule ( PF18-3 molecule) and its role in MTSC4-induced thymocyte apoptosis. The characterization of PF18-3 molecule expression has been conducted by FACS analysis. PF18-3 molecules have been found to express on MTSC4 as well as on Con A activated but not freshly isolated thymocytes. Up-regulated expression of PF18-3 molecules has been also observed on thymocytes after being co-cultured with MTSC4 for 48 h. The results from FACS analyses by Pl staining for detecting apoptosis-related hypodiploid and by PF18-3 mAb staining reveal that PF18-3 molecules expresss specifically on the apoptotic subgroup of thymocytes with high hypodiploid content. The PF18-3 molecule expressed on apoptotic thymocytes展开更多
Liver X receptors(LXRs)are known as key transcription factors in lipid metabolism and have been reported to play an important role in T-cell proliferation.However,whether LXRs play a role in thymocyte development rema...Liver X receptors(LXRs)are known as key transcription factors in lipid metabolism and have been reported to play an important role in T-cell proliferation.However,whether LXRs play a role in thymocyte development remains largely unknown.Here,we demonstrated that LXRβdeficiency caused a reduction in single-positive(SP)thymocytes,whereas the transitions from the double-negative to SP stage were normal.Meanwhile,LXRβ-null SP thymocytes exhibited increased apoptosis and impairment of the IL-7Rα-Bcl2 axis.In addition,the LXR agonist T0901317 promoted the survival of SP thymocytes with enhanced IL-7Rαexpression in wild-type mice but not in LXRβ-deficient mice.Mechanistically,LXRβpositively regulated the expression of IL-7Rαvia direct binding to the Il7r allele in SP thymocytes,and forced expression of IL-7Rαor Bcl2 restored the survival of LXRβ-defective SP thymocytes.Thus,our results indicate that LXRβfunctions as an important transcription factor upstream of IL-7Rαto promote the survival of SP thymocytes.展开更多
Emerging studies highlight the import-ance of metabolic reprogramming in T cell development and function, although how these processes are regulated remains to be fully understood. Recent advances in dissecting the ro...Emerging studies highlight the import-ance of metabolic reprogramming in T cell development and function, although how these processes are regulated remains to be fully understood. Recent advances in dissecting the roles of Sinl-m T0RC2 signaling in early thymocyte development provide new in sight into the dynamic in terplay between immune signaling and cell metabolism, as well as the crucial role in directi ng thymocyte pro life ration and development.展开更多
TCRαβTCD4-CD8+ thymocytes are heterogeneity. They may undergo phenotypic and functional maturation within thymic medulla. Medullary-type CD8SP thymocytes were divided into seven subsets based on phenotypic analysis,...TCRαβTCD4-CD8+ thymocytes are heterogeneity. They may undergo phenotypic and functional maturation within thymic medulla. Medullary-type CD8SP thymocytes were divided into seven subsets based on phenotypic analysis, and their precursor-progeny relationship along with the differential pathway was also delineated. To further testify the validity of the maturation pathway, we purified 6C10-CD69+ cells representing the early stage and 6C10-Qa-2+ cells representing the later stage among medullary-type CD8SP thymocytes and compared their functional maturation levels. CD8+ T cells of spleen were used as the control. It is shown that there is no obvious difference of proliferation ability among these three subsets; however, intracytoplasmic cytokine assay shows that there is a hierarchy of IFN-γ and TNFα secretion among these subsets, strikingly comparable to their phenotypic status among medullary type CD8SP thymocytes. The bioassays of IL-2 and IFN-γ in culture supernatant give the similar results.展开更多
The migrating TdT<sup>+</sup> thymocytes can die in other tissues, promoting the surrounding cells’ renewing likes holocrine secretion does. To clarify the role of TdT-enzyme for this function of progenit...The migrating TdT<sup>+</sup> thymocytes can die in other tissues, promoting the surrounding cells’ renewing likes holocrine secretion does. To clarify the role of TdT-enzyme for this function of progenitor lymphocytes, their extracellular media with its components included by living cells analyzed <em>in vitro</em> before and after<em> in vivo</em> irradiation of donor rats. The nucleoid with DNase-sensitive (free) DNA and TdT activity discovered in extracellular media conditioned preliminary by spontaneous apoptotic death of a minor part of the thymocyte’s suspension <em>in vitro</em>. The penetration of labeled products of non-template synthesis with free DNA’ primers from media into cells by pinocytosis confirmed by exogenous polymeric DNA marked artificially. The DNA penetration into cells follows an increase of the cell’s viability and acceleration of spontaneous intracellular DNA-synthesis controlled with labeled thymidine uptake. Both phenomena are typical for either the lowest initial concentration of intact cells or their preliminary irradiation <em>in vivo</em>. The data point to possible involvement of apoptotic decay of TdT<sup>+</sup> cells in the reutilization of the extracellular DNA fragments for reparation/regeneration of surrounding living cells.展开更多
It is well documented that dietary restriction can prevent many different diseases and extend the life spans of different rodent species. In the previous study, we reported that intermittent fasting (IF) as well as mo...It is well documented that dietary restriction can prevent many different diseases and extend the life spans of different rodent species. In the previous study, we reported that intermittent fasting (IF) as well as moderate dietary restriction ameliorated the allergic dermatitis in ICR mice. In the present study, we demonstrated the ameliorative effects of IF on allergic dermatitis in NC/Nga mice, a strain known as a model for atopic dermatitis. Interestingly, the total number of CD4+CD8+ double positive thymocyte in mice after IF significantly decreased in comparison to that in mice fed ad libitum. Although it was reported that an immunosuppressive compound inhibited the contact allergic response by inducing the CD4+CD25+ regulatory T-cells, IF did not affect regulatory T cells in the present study. These results suggested that CD4+CD8+ double positive thymocytes play an important role in the regulation of allergy by IF in NC/Nga mice.展开更多
T-cell development ensures the formation of diverse repertoires of T-cell receptors(TCRs)that recognize a variety of antigens.Glycosylation is a major posttranslational modification present in virtually all cells,incl...T-cell development ensures the formation of diverse repertoires of T-cell receptors(TCRs)that recognize a variety of antigens.Glycosylation is a major posttranslational modification present in virtually all cells,including T-lymphocytes,that regulates activity/functions.Although these structures are known to be involved in TCR-selection in DP thymocytes,it is unclear how glycans regulate other thymic development processes and how they influence susceptibility to disease.Here,we discovered stage-specific glycome compositions during T-cell development in human and murine thymocytes,as well as dynamic alterations.After restricting the N-glycosylation profile of thymocytes to high-mannose structures,using specific glycoengineered mice(Rag1CreMgat1fl/fl),we showed remarkable defects in key developmental checkpoints,includingß-selection,regulatory T-cell generation andγδT-cell development,associated with increased susceptibility to colon and kidney inflammation and infection.We further demonstrated that a single N-glycan antenna(modeled in Rag1CreMgat2fl/fl mice)is the sine-qua-non condition to ensure normal development.In conclusion,we revealed that mannosylated thymocytes lead to a dysregulation in T-cell development that is associated with inflammation susceptibility.展开更多
A mouse chemokine MIP-2(macrophage in-flamatory protein 2) is constitutively expressed not only by peritoneal macrophages, but also by fresh thymic stromal cells, based on RT-PCR detection. Moreover, the specific rece...A mouse chemokine MIP-2(macrophage in-flamatory protein 2) is constitutively expressed not only by peritoneal macrophages, but also by fresh thymic stromal cells, based on RT-PCR detection. Moreover, the specific receptor of MIP-2 is expressed at different levels among four main subgroups of murine thymocytes including DN, DP, CD4SP and CD8SP. By the chemotaxis assays with Boyden chamber, we proved that the recombinant mouse MIP-2 can chemoattract the four main subgroups of thymocytes in different degrees, it mainly chemoattract the DP and SP subgroups. We firstly reported that MIP-2 is involved in the regulation of the directional migration of developing thymocytes.展开更多
Background:Endotoxin tolerance(ET)is a protective phenomenon in which pre-treatment with a tolerance dose of lipopolysaccharide(LPS)leads to dramatically elevated survival.Accumulating evidence has shown that peripher...Background:Endotoxin tolerance(ET)is a protective phenomenon in which pre-treatment with a tolerance dose of lipopolysaccharide(LPS)leads to dramatically elevated survival.Accumulating evidence has shown that peripheral T cells contribute to the induction of ET.However,what happens to T cell development in the thymus under ET conditions remains unclear.The purpose of this study was to analyze the alterations in thymocyte populations(double-positive[DP]and single-positive[SP]cells)under ET conditions.Methods:Mice were intraperitoneally injected with LPS at a concentration of 5 mg/kg to establish an LPS tolerance model and were divided into two groups:a group examined 72 h after LPS injection(72-h group)and a group examined 8 days after LPS injection(8-day group).Injection of phosphate-buffered saline was used as a control(control group).Changes in thymus weight,cell counts,and morphology were detected in the three groups.Moreover,surface molecules such as CD4,CD8,CD44,CD69,and CD62L were analyzed using flow cytometry.Furthermore,proliferation,apoptosis,cytokine production,and extracellular signal-regulated kinase(ERK)pathway signaling were analyzed in thymocyte populations.The polymorphism and length of the T-cell receptor(TCR)P chain complementarity-determining region 3(CDR3)were analyzed using capillary electrophoresis DNA laser scanning analysis(ABI 3730).Results:Thymus weight and cell counts were decreased in the early stage but recovered by the late stage in a murine model of LPS-induced ET.Moreover,the proportions of DP cells(control:72.130±4.074,72-h:10.600±3.517,8-day:84.770±2.228),CD4+SP cells(control:15.770±4.419,72-h:44.670±3.089,8-day:6.367±0.513),and CD8+SP cells(control:7.000±1.916,72-h:34.030±3.850,8-day:5.133±0.647)were obviously different at different stages of ET.The polymorphism and length of TCR β chain CDR3 also changed obviously,indicating the occurrence of TCR rearrangement and thymocyte diversification.Further analysis showed that the expression of surface molecules,including CD44,CD69,and CD62L,on thymocyte populations(DP and SP cells)were changed to different degrees.Finally,the proliferation,apoptosis,cytokine production,and ERK pathway signaling of thymocyte populations were changed significantly.Conclusion:These data reveal that alterations in thymocyte populations might contribute to the establishment of ET.展开更多
Glucose metabolism plays a key role in thymocyte development. The mammalian target of rapamycin complex 2 (mT0RC2) is a critical regulator of cell growth and metabolism, but its role in early thymocyte development and...Glucose metabolism plays a key role in thymocyte development. The mammalian target of rapamycin complex 2 (mT0RC2) is a critical regulator of cell growth and metabolism, but its role in early thymocyte development and metabolism has not been fully studied. We show here that genetic ablation of Sinl, an essential component of mTORC2, in T lineage cells results in severely impaired thymocyte development at the CD4^- CD8^- double negative (DN) stages but not at the CD4^+ CD8^+ double positive (DP) or later stages. Notably, Sinl-deficient DN thymocytes show markedly reduced proliferation and glycolysis.Importantly, we discover that the M2 isoform of pyruvate kinase (PKM2) is a novel and crucial Sinl effector in promoting DN thymocyte development and metabolism. At the molecular level, we show that Sinl-mTORC2 controls PKM2 expression through an AKT-dependent PPAR-y nuclear translocation. Together, our study unravels a novel mTORC2-PPAR-γ-PKM2 pathway in immune-metabolic regulation of early thymocyte development.展开更多
Thymic medullary type epithelial cell line (MTEC1), which expressed H\|2D d and Ia\+d, was derived from BALB/c mouse. MTEC1 cells were introduced by intrathymic injection into irradiated H\|2\+b mice reconstituted wit...Thymic medullary type epithelial cell line (MTEC1), which expressed H\|2D d and Ia\+d, was derived from BALB/c mouse. MTEC1 cells were introduced by intrathymic injection into irradiated H\|2\+b mice reconstituted with H\|2 b×d F1 bone marrow cells. Two months later, the injected MTEC1 cells were found to be still present in the recipient thymus. Splenocytes from chimeric mice, in \%in vitro\% functional assays, were analyzed to investigate whether the MTEC1 cells \%in vivo\% could induce the production of H\|2\+d restricted antigen\|specific T cells. The H\|2\+d restricted VSV\|antigen specific proliferating and IL\|2 producing T cells as well as H\|2\+d restricted influenza virus specific cytotoxic T cells were found in chimeric mice injected with MTEC1 cells, and these cells were shown to be tolerant to H\|2\+d self\|antigen. On the contrary, H\|2\+d restricted antigen\|specific and H\|2\+d self\|antigen tolerant T cells were not shown in control mice injected with saline. These results suggest that intrathymically injected MTEC1 cells could induce T lineage cell development and functional maturation in the intact thymus. A hypothesis of "second thymic selection" in thymic medulla has been postulated and its implication discussed.展开更多
Riboflavin, suggested to be a radiosensitizer, was studied in murine thymocytes and human hepatoma L02 cell line in vitro with MTT method and fluorescence microscopy. When the murine thymocytes treated with 5-400 μmo...Riboflavin, suggested to be a radiosensitizer, was studied in murine thymocytes and human hepatoma L02 cell line in vitro with MTT method and fluorescence microscopy. When the murine thymocytes treated with 5-400 μmol/L riboflavin were irradiated by 5 Gy 60Co γ ionizing radiation, the low concentration groups, i.e. treated with 5-50 μmol/L riboflavin, showed a different surviving fractions-time relating correlation compared with the high concentration groups, i.e. treated with 100-400 μmol/L riboflavin. The former had a high survival level at the end of irradiation, but which, after 4-h incubation, decreased rapidly to a low level. On the contrary, the high concentration groups showed a low survival level at the end of irradiation, and a poor correlation was found between the surviving fraction and the incubation time, after 4 h a little difference was observed. The results of fluorescence microscopy indicated that under low concentration conditions, the riboflavin localized mainly in nucleus (both perinuclear area and inside of nuclear membrane), while under high concentration conditions, intensive riboflavin also localized around cytoplasmic membranes. Thus we can conclude: the riboflavin had radiosensitivity effect on DNA under low concentration conditions, and enhanced the damage to cytoplasmic membrane under high concentration conditions. Also the most effective concentration of riboflavin can be evaluated to be approximate 100 μmol/L.展开更多
A murine CD4+ thymocyte subset with phenotype of TCRαβ + 3G11- 6C10- CD4 + CD8- CD69 + /- HSAmed/lo contains the cells in relatively functional matured status. The functional property of the cells in this subset is ...A murine CD4+ thymocyte subset with phenotype of TCRαβ + 3G11- 6C10- CD4 + CD8- CD69 + /- HSAmed/lo contains the cells in relatively functional matured status. The functional property of the cells in this subset is characterized by the unique pattern of cytokine production at transitional stage from ThO to Th2 type with the latter being the dominant type. After being co-cultured with murine thymic medullary epithelial cell line (MTEC1) cells, a murine展开更多
基金This study was supported by the National Natural Science Foundation of China(30901909).
文摘Objective:To determine the effect of an immunosuppressive active component (periploside A) isolated from the stem bark of Periplocae Cortex (Periploca sepium Bge.),a Chinese medicinal herb used in the treatment of rheumatoid arthritis for centuries in China,on positive selection of thymocytes in vitro.Methods:Female C57BL/6 mice at 6 weeks of age were housed in specific pathogen-free conditions.Double-positive thymocytes from C57BL/6 mice were induced into positive selection in vitro with or without periploside A treatment.Cell viability and expression of CD69,CD4,and CD8 were analyzed by flow cytometry.Results:Flow cytometric examination of thymocyte populations revealed that the percentage of CD8+ single-positive thymocytes was decreased by periploside A upon differentiation induced by an anti-CD3 antibody.However,the percentage of CD4+ single-positive thymocytes was decreased by periploside A upon differentiation induced by phorbol 12-myristate 13-acetate/ionomycin.Expression of CD69 plays a major role in prohibiting differentiation of thymocytes.Treatment with periploside A decreased CD69 expression in thymocytes.Conclusion:These results demonstrate that periploside A influences positive selection of thymocytes in vitro.
基金Project supported by the National Natural Science Foundation of China and China Medical Board, Rockefeller Foundation.
文摘Murine CD4+CD8- (CD4SP) thymocyte subset is a heterogeneous population, in which the Qa-2- cells are less functional, whereas the Qa-2+ cells are fully functional. Evidence is provided here that the transition from Qa-2- to Qa-2+ CD4SP thymocytes is an intrathymic process of differentiation induced by thymic medullary-type epithelial cells. The separated Qa-2-CD4SP could be induced to express Qa-2 molecules up to 84%- 89% of the total viable celb after cocultured for 3d with MTEC1 cells, a murine thymic medullary type epithelial cell line established in our laboratory. Kinetic study showed that both the percentage of Qa-2+ cells and the density of the expressed Qa-2 molecules on CD4SP thymocytes induced by MTEC1 were progressively increasing in 72-h cultures. The MTECl-induced Qa-2+CD4SP thymocytes were fully functional, which exhibited capabilities of proliferation and cytokine secretion in response to Con A stimulation as high as those of freshly isolated Qa-2+CD4SP thymocytes. The profile of
文摘Using terminal deoxynucleotide transferase mediated dUTP digoxigenin nick end labeling (TUNEL) assay and propidium iodide DNA staining flow cytometry assay, the effects of mouse thymic dendritic cells (MTSC4) on the process of programmed cell death of thymocytes in vitro were investigated. It was noticed that thymocytes bound to MTSC4 used in this study. That the percentages of apoptotic nuclei of the bound thymocytes on MTSC4 were much higher than those of medium cultured thymocytes, while the bound thymocytes on mouse thymic epithelial cell (MTEC1) showed much lower percentages of apoptosis. FACS analysis quantitatively confirmed the observation. Phenotype analysis showed that MTSC4 induced the deletion of CD4+CD8+ cells and CD4+CD8 cells in 18 h of coculture. The results suggest that the negative selection of medullary thymocytes may be achieved by thymic dendritic cells through their enhancing effects on apoptosis.
文摘Phenotypic analysis of the medullary-type CD4 CD8+ (CD8SP) thymocytes has revealed phenotypic heterogeneity within this cell population. The phenotype of mature peripheral CD8+T cells is TCRαβ+CD3+Qa-2+HSA3G11 6C10 , whereas in the medullary-type CD8SP thymocytes, 20% are Qa-2+; 33%, HAS ; 30%, 3G11 ; and 70% are 6C10 . The disparate expression patterns of these four cell surface markers suggest that medullary-type CD8SP thymocytes may undergo phenotypic maturation process. According to the distribution of these four celi surface markers, six subgroups of CD8SP thymocytes have been identified. The precursor-progeny relationship along with developmental pathway is postulated as follows: 6C10+HSA+3G11 Qa-2 - 6C10+HSA+ 3G11+Qa-2 6C10 HSA+3G11+Qa-2 -6C10 HSA 3G11 +Qa-2 -6C10 HSA 3G11 Qa-2 -6C10 HA S 3G11 Qa-2+, the cells inthe last subgroup exit the thymus and home into periphery.
基金Project supported by the National Natural Science Foundation of China (Grant No. 39730410).
文摘The presence of a relatively mature CD4 <sup>+</sup> CD8<sup>-</sup> （SP） T cell subset in mouse thymus has been demonstrated. Composing of 10% of total CD4SP thymocytes, this subset is defined by the absence of 3G11 and 6C10 expression with a phenotype of CD69<sup>+/-</sup>, HSA<sup>med/lo</sup> and heterogeneous for Qa-2 expression. The proliferation capability of TCRαβ<sup>+</sup> 3G11<sup>-</sup> 6C10<sup>-</sup> CD4<sup>+</sup> CD8<sup>-</sup> thymocytes was high while using Con A stimulus. And Con A stimulation could result in secretion of IL-4, IL-10, IL-6 and a little amount of IFNγ. IL-2 was barely detectable. This is distinct from typical Th0 type cytokines. The cells of this subset were NK1.1 negative, but strongly expressed GATA-3 mRNA. The results suggest that the CD4<sup>+</sup> subset of 3G11<sup>-</sup> 6C10<sup>-</sup> NK1.1<sup>-</sup> phenotype possesses immunocompetent cells with functions characteristic of Th2-like cytokines, which may indicate the cells at transitional status from Th0 to Th2, with a propensity to Th2.
文摘PF18-3 monoclonal antibody (mAb), one of the rat mAbs against mouse thymic stromal cells (MTSC), has been found to inhibit thymocyte apoptosis induced by a mouse thymic dendritic cell line, MTSC4, in previous co-culture study. The aim of this research is to investigate the character of PF18-3 mAb recognized molecule ( PF18-3 molecule) and its role in MTSC4-induced thymocyte apoptosis. The characterization of PF18-3 molecule expression has been conducted by FACS analysis. PF18-3 molecules have been found to express on MTSC4 as well as on Con A activated but not freshly isolated thymocytes. Up-regulated expression of PF18-3 molecules has been also observed on thymocytes after being co-cultured with MTSC4 for 48 h. The results from FACS analyses by Pl staining for detecting apoptosis-related hypodiploid and by PF18-3 mAb staining reveal that PF18-3 molecules expresss specifically on the apoptotic subgroup of thymocytes with high hypodiploid content. The PF18-3 molecule expressed on apoptotic thymocytes
基金This work was supported by grants from the National Key Research and Development Program of China(No.2016YFA0502203 to X.Z.and No.2016YFA0502204 to Y.W.)the National Natural Science Foundation of China(No.81571537 to T.Z.,No.31770949 to X.Z.,No.31770972 to Z.X.,and No.81571604 to J.Z.)the Chongqing Basic and Frontier Research Project(No.cstc2015jcyjBX0086 to H.He.).
文摘Liver X receptors(LXRs)are known as key transcription factors in lipid metabolism and have been reported to play an important role in T-cell proliferation.However,whether LXRs play a role in thymocyte development remains largely unknown.Here,we demonstrated that LXRβdeficiency caused a reduction in single-positive(SP)thymocytes,whereas the transitions from the double-negative to SP stage were normal.Meanwhile,LXRβ-null SP thymocytes exhibited increased apoptosis and impairment of the IL-7Rα-Bcl2 axis.In addition,the LXR agonist T0901317 promoted the survival of SP thymocytes with enhanced IL-7Rαexpression in wild-type mice but not in LXRβ-deficient mice.Mechanistically,LXRβpositively regulated the expression of IL-7Rαvia direct binding to the Il7r allele in SP thymocytes,and forced expression of IL-7Rαor Bcl2 restored the survival of LXRβ-defective SP thymocytes.Thus,our results indicate that LXRβfunctions as an important transcription factor upstream of IL-7Rαto promote the survival of SP thymocytes.
文摘Emerging studies highlight the import-ance of metabolic reprogramming in T cell development and function, although how these processes are regulated remains to be fully understood. Recent advances in dissecting the roles of Sinl-m T0RC2 signaling in early thymocyte development provide new in sight into the dynamic in terplay between immune signaling and cell metabolism, as well as the crucial role in directi ng thymocyte pro life ration and development.
基金supported by the National Natural Science Foundation of China(Grant No.39230320)the National"973"Project
文摘TCRαβTCD4-CD8+ thymocytes are heterogeneity. They may undergo phenotypic and functional maturation within thymic medulla. Medullary-type CD8SP thymocytes were divided into seven subsets based on phenotypic analysis, and their precursor-progeny relationship along with the differential pathway was also delineated. To further testify the validity of the maturation pathway, we purified 6C10-CD69+ cells representing the early stage and 6C10-Qa-2+ cells representing the later stage among medullary-type CD8SP thymocytes and compared their functional maturation levels. CD8+ T cells of spleen were used as the control. It is shown that there is no obvious difference of proliferation ability among these three subsets; however, intracytoplasmic cytokine assay shows that there is a hierarchy of IFN-γ and TNFα secretion among these subsets, strikingly comparable to their phenotypic status among medullary type CD8SP thymocytes. The bioassays of IL-2 and IFN-γ in culture supernatant give the similar results.
文摘The migrating TdT<sup>+</sup> thymocytes can die in other tissues, promoting the surrounding cells’ renewing likes holocrine secretion does. To clarify the role of TdT-enzyme for this function of progenitor lymphocytes, their extracellular media with its components included by living cells analyzed <em>in vitro</em> before and after<em> in vivo</em> irradiation of donor rats. The nucleoid with DNase-sensitive (free) DNA and TdT activity discovered in extracellular media conditioned preliminary by spontaneous apoptotic death of a minor part of the thymocyte’s suspension <em>in vitro</em>. The penetration of labeled products of non-template synthesis with free DNA’ primers from media into cells by pinocytosis confirmed by exogenous polymeric DNA marked artificially. The DNA penetration into cells follows an increase of the cell’s viability and acceleration of spontaneous intracellular DNA-synthesis controlled with labeled thymidine uptake. Both phenomena are typical for either the lowest initial concentration of intact cells or their preliminary irradiation <em>in vivo</em>. The data point to possible involvement of apoptotic decay of TdT<sup>+</sup> cells in the reutilization of the extracellular DNA fragments for reparation/regeneration of surrounding living cells.
文摘It is well documented that dietary restriction can prevent many different diseases and extend the life spans of different rodent species. In the previous study, we reported that intermittent fasting (IF) as well as moderate dietary restriction ameliorated the allergic dermatitis in ICR mice. In the present study, we demonstrated the ameliorative effects of IF on allergic dermatitis in NC/Nga mice, a strain known as a model for atopic dermatitis. Interestingly, the total number of CD4+CD8+ double positive thymocyte in mice after IF significantly decreased in comparison to that in mice fed ad libitum. Although it was reported that an immunosuppressive compound inhibited the contact allergic response by inducing the CD4+CD25+ regulatory T-cells, IF did not affect regulatory T cells in the present study. These results suggested that CD4+CD8+ double positive thymocytes play an important role in the regulation of allergy by IF in NC/Nga mice.
基金Funded by the“2022 Lupus Research Alliance(LRA)Lupus Innovation Award”.Institutional funding from the Portuguese Foundation for Science and Technology(FCT):projects NORTE-01-0145-FEDER-000029,POCI-01/0145-FEDER-016601,POCI-01-0145-FEDER-028772,and PTDC/MEC-REU/28772/2017(SSP)This study was co-funded by the European Union(ERC Synergy,GlycanSwitch,101071386)+1 种基金Views and opinions expressed are,however,those of the author(s)only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency.The study was also co-funded by the European Union,GlycanTrigger project,Grant Agreement No:101093997Views and opinions expressed are,however,those of the author(s)only and do not necessarily reflect those of the European Union or European Health and Digital Executive Agency.Neither the European Union nor the granting authority can be held responsible for them.A grant was received from the Portuguese group of study in autoimmune diseases(NEDAI)to SSP.MMV(PD/BD/135452/2017,COVID/BD/152488/2022)received funding from the FCT.
文摘T-cell development ensures the formation of diverse repertoires of T-cell receptors(TCRs)that recognize a variety of antigens.Glycosylation is a major posttranslational modification present in virtually all cells,including T-lymphocytes,that regulates activity/functions.Although these structures are known to be involved in TCR-selection in DP thymocytes,it is unclear how glycans regulate other thymic development processes and how they influence susceptibility to disease.Here,we discovered stage-specific glycome compositions during T-cell development in human and murine thymocytes,as well as dynamic alterations.After restricting the N-glycosylation profile of thymocytes to high-mannose structures,using specific glycoengineered mice(Rag1CreMgat1fl/fl),we showed remarkable defects in key developmental checkpoints,includingß-selection,regulatory T-cell generation andγδT-cell development,associated with increased susceptibility to colon and kidney inflammation and infection.We further demonstrated that a single N-glycan antenna(modeled in Rag1CreMgat2fl/fl mice)is the sine-qua-non condition to ensure normal development.In conclusion,we revealed that mannosylated thymocytes lead to a dysregulation in T-cell development that is associated with inflammation susceptibility.
基金This work was supported by the International Center for Genetic Engineering and Biotechnology (ICGEB) (Grant No. 98/016) and the National "973" Project of China (Grant No. G1999053904).
文摘A mouse chemokine MIP-2(macrophage in-flamatory protein 2) is constitutively expressed not only by peritoneal macrophages, but also by fresh thymic stromal cells, based on RT-PCR detection. Moreover, the specific receptor of MIP-2 is expressed at different levels among four main subgroups of murine thymocytes including DN, DP, CD4SP and CD8SP. By the chemotaxis assays with Boyden chamber, we proved that the recombinant mouse MIP-2 can chemoattract the four main subgroups of thymocytes in different degrees, it mainly chemoattract the DP and SP subgroups. We firstly reported that MIP-2 is involved in the regulation of the directional migration of developing thymocytes.
基金the Project of the Guizhou Provincial Department of Science and Technology(No.QKH-JC-2018-1428)the National Natural Science Foundation of China(No.31760258)the Guizhou Province Graduate Research Fund(No.YJSCXJH-2020-093).
文摘Background:Endotoxin tolerance(ET)is a protective phenomenon in which pre-treatment with a tolerance dose of lipopolysaccharide(LPS)leads to dramatically elevated survival.Accumulating evidence has shown that peripheral T cells contribute to the induction of ET.However,what happens to T cell development in the thymus under ET conditions remains unclear.The purpose of this study was to analyze the alterations in thymocyte populations(double-positive[DP]and single-positive[SP]cells)under ET conditions.Methods:Mice were intraperitoneally injected with LPS at a concentration of 5 mg/kg to establish an LPS tolerance model and were divided into two groups:a group examined 72 h after LPS injection(72-h group)and a group examined 8 days after LPS injection(8-day group).Injection of phosphate-buffered saline was used as a control(control group).Changes in thymus weight,cell counts,and morphology were detected in the three groups.Moreover,surface molecules such as CD4,CD8,CD44,CD69,and CD62L were analyzed using flow cytometry.Furthermore,proliferation,apoptosis,cytokine production,and extracellular signal-regulated kinase(ERK)pathway signaling were analyzed in thymocyte populations.The polymorphism and length of the T-cell receptor(TCR)P chain complementarity-determining region 3(CDR3)were analyzed using capillary electrophoresis DNA laser scanning analysis(ABI 3730).Results:Thymus weight and cell counts were decreased in the early stage but recovered by the late stage in a murine model of LPS-induced ET.Moreover,the proportions of DP cells(control:72.130±4.074,72-h:10.600±3.517,8-day:84.770±2.228),CD4+SP cells(control:15.770±4.419,72-h:44.670±3.089,8-day:6.367±0.513),and CD8+SP cells(control:7.000±1.916,72-h:34.030±3.850,8-day:5.133±0.647)were obviously different at different stages of ET.The polymorphism and length of TCR β chain CDR3 also changed obviously,indicating the occurrence of TCR rearrangement and thymocyte diversification.Further analysis showed that the expression of surface molecules,including CD44,CD69,and CD62L,on thymocyte populations(DP and SP cells)were changed to different degrees.Finally,the proliferation,apoptosis,cytokine production,and ERK pathway signaling of thymocyte populations were changed significantly.Conclusion:These data reveal that alterations in thymocyte populations might contribute to the establishment of ET.
基金the National Natural Science Foundation of China (31470845, 81430033, and 31670896)Shanghai Science and Technology Commission (13JC1404700)Shanghai Rising-Star Program (16QA1403300).
文摘Glucose metabolism plays a key role in thymocyte development. The mammalian target of rapamycin complex 2 (mT0RC2) is a critical regulator of cell growth and metabolism, but its role in early thymocyte development and metabolism has not been fully studied. We show here that genetic ablation of Sinl, an essential component of mTORC2, in T lineage cells results in severely impaired thymocyte development at the CD4^- CD8^- double negative (DN) stages but not at the CD4^+ CD8^+ double positive (DP) or later stages. Notably, Sinl-deficient DN thymocytes show markedly reduced proliferation and glycolysis.Importantly, we discover that the M2 isoform of pyruvate kinase (PKM2) is a novel and crucial Sinl effector in promoting DN thymocyte development and metabolism. At the molecular level, we show that Sinl-mTORC2 controls PKM2 expression through an AKT-dependent PPAR-y nuclear translocation. Together, our study unravels a novel mTORC2-PPAR-γ-PKM2 pathway in immune-metabolic regulation of early thymocyte development.
文摘Thymic medullary type epithelial cell line (MTEC1), which expressed H\|2D d and Ia\+d, was derived from BALB/c mouse. MTEC1 cells were introduced by intrathymic injection into irradiated H\|2\+b mice reconstituted with H\|2 b×d F1 bone marrow cells. Two months later, the injected MTEC1 cells were found to be still present in the recipient thymus. Splenocytes from chimeric mice, in \%in vitro\% functional assays, were analyzed to investigate whether the MTEC1 cells \%in vivo\% could induce the production of H\|2\+d restricted antigen\|specific T cells. The H\|2\+d restricted VSV\|antigen specific proliferating and IL\|2 producing T cells as well as H\|2\+d restricted influenza virus specific cytotoxic T cells were found in chimeric mice injected with MTEC1 cells, and these cells were shown to be tolerant to H\|2\+d self\|antigen. On the contrary, H\|2\+d restricted antigen\|specific and H\|2\+d self\|antigen tolerant T cells were not shown in control mice injected with saline. These results suggest that intrathymically injected MTEC1 cells could induce T lineage cell development and functional maturation in the intact thymus. A hypothesis of "second thymic selection" in thymic medulla has been postulated and its implication discussed.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39830090).
文摘Riboflavin, suggested to be a radiosensitizer, was studied in murine thymocytes and human hepatoma L02 cell line in vitro with MTT method and fluorescence microscopy. When the murine thymocytes treated with 5-400 μmol/L riboflavin were irradiated by 5 Gy 60Co γ ionizing radiation, the low concentration groups, i.e. treated with 5-50 μmol/L riboflavin, showed a different surviving fractions-time relating correlation compared with the high concentration groups, i.e. treated with 100-400 μmol/L riboflavin. The former had a high survival level at the end of irradiation, but which, after 4-h incubation, decreased rapidly to a low level. On the contrary, the high concentration groups showed a low survival level at the end of irradiation, and a poor correlation was found between the surviving fraction and the incubation time, after 4 h a little difference was observed. The results of fluorescence microscopy indicated that under low concentration conditions, the riboflavin localized mainly in nucleus (both perinuclear area and inside of nuclear membrane), while under high concentration conditions, intensive riboflavin also localized around cytoplasmic membranes. Thus we can conclude: the riboflavin had radiosensitivity effect on DNA under low concentration conditions, and enhanced the damage to cytoplasmic membrane under high concentration conditions. Also the most effective concentration of riboflavin can be evaluated to be approximate 100 μmol/L.
文摘A murine CD4+ thymocyte subset with phenotype of TCRαβ + 3G11- 6C10- CD4 + CD8- CD69 + /- HSAmed/lo contains the cells in relatively functional matured status. The functional property of the cells in this subset is characterized by the unique pattern of cytokine production at transitional stage from ThO to Th2 type with the latter being the dominant type. After being co-cultured with murine thymic medullary epithelial cell line (MTEC1) cells, a murine
