AIM: To explore the potential of contrast-enhanced computed tomography(CECT) using Exi Tron nano6000 for assessment of liver lesions in mouse models.METHODS: Three mouse models of liver lesions were used: bile duct li...AIM: To explore the potential of contrast-enhanced computed tomography(CECT) using Exi Tron nano6000 for assessment of liver lesions in mouse models.METHODS: Three mouse models of liver lesions were used: bile duct ligation(BDL),lipopolysaccharide(LPS)/D-galactosamine(D-Gal N),and alcohol.After injection with the contrast agent Exi Tron nano6000,the mice were scanned with micro-CT.Liver lesions were evaluated using CECT images,hematoxylin and eosin staining,and serum aminotransferase levels.Macrophage distribution in the injury models was shown by immunohistochemical staining of CD68.The in vitro studies measured the densities of RAW264.7 under different conditions by CECT.RESULTS: In the in vitro studies,CECT provided specific and strong contrast enhancement of liver in mice.CECT could present heterogeneous images anddensities of injured livers induced by BDL,LPS/D-Gal N,and alcohol.The liver histology and immunochemistry of CD68 demonstrated that both dilated biliary tracts and necrosis in the injured livers could lead to the heterogeneous distribution of macrophages.The in vitro study showed that the RAW264.7 cell masses had higher densities after LPS activation.CONCLUSION: Micro-CT with the contrast agent Exi Tron nano6000 is feasible for detecting various liver lesions by emphasizing the heterogeneous textures and densities of CECT images.展开更多
RIG-I （retinoid acid-inducible gene-I）, a putative RNA helicase with a cytoplasmic caspase-recrultment domain （CARD）, was identified as a pattem-recognition receptor （PRR） that mediates antiviral immunity by ind...RIG-I （retinoid acid-inducible gene-I）, a putative RNA helicase with a cytoplasmic caspase-recrultment domain （CARD）, was identified as a pattem-recognition receptor （PRR） that mediates antiviral immunity by inducing type I interferon production. To further study the biological function of RIG-I, we generated Rig-I^-/- mice through homologous recombination, taking a different strategy to the previously reported strategy. Our Rig-I^-/- mice are viable and fertile. Histological analysis shows that Rig-I^-/ mice develop a colitis-like phenotype and increased susceptibility to dextran sulfate sodium-induced colitis. Accordingly, the size and number of Peyer＇s patches dramatically decreased in mutant mice. The peripheral T-cell subsets in mutant mice are characterized by an increase in effector T cells and a decrease in naive T cells, indicating an important role for Rig-I in the regulation ofT-cell activation. It was further found that Rig-I deficiency leads to the downregulation of G protein αi2 subunit （Gαi2） in various tissues, including T and B lymphocytes. By contrast, upregulation of Rig-I in NB4 cells that are treated with ATRA is accompanied by elevated Gαi2 expression. Moreover, Gαi2 promoter activity is increased in co-transfected NIH3T3 cells in a Rig-I dose-dependent manner. All these findings suggest that Rig-I has crucial roles in the regulation of Gαi2 expression and T-cell activation. The development of colitis may be, at least in part, associated with downregulation of Gαi2 and disturbed T-cell homeostasis.展开更多
Parthenogenetic embryonic stem （pES） cells provide a valuable in vitro model system for studying the molecular mechanisms that underlie genomic imprinting. However, the pluripotency of pES cells and the expression p...Parthenogenetic embryonic stem （pES） cells provide a valuable in vitro model system for studying the molecular mechanisms that underlie genomic imprinting. However, the pluripotency of pES cells and the expression profiles of paternally expressed imprinted genes have not been fully explored. In this study, three mouse pES cell lines were established and the differentiation potential of these cells in extended culture was evaluated. The undifferentiated cells had a normal karyotype and homozygous genome, and expressed ES-cell-specific molecular markers. The cells remained undifferentiated after more than 50 passages and exhibited pluripotent differentiation capacity. All three lines of the established ES cells produced teratomas; two lines of ES cells produced chimeras and germline transmission. Furthermore, activation of the paternally expressed imprinted genes Snrpn, U2afl-rsl, Peg3, Impact, Zfp127, Dlkl and Mest in these cells was detected. Some paternally expressed imprinted genes were found to be expressed in the blastocyst stage of parthenogenetically activated embryos in vitro and their expression level increased with extended pES cell culture. Furthermore, our data show that the activation of these paternally expressed imprinted genes in pES cells was associated with a change in the methylation of the related differentially methylated regions. These findings provide direct evidence for the pluripotency of pES cells and demonstrate the association between the DNA methylation pattern and the activa- tion of paternally expressed imprinted genes in pES cells. Thus, the established ES cell lines provide a valuable model for studying epigenetic regulation in mammalian development.展开更多
Generation of transgenic mice by DNA microinjection has become one of the most important technologies in studying gene function in vivo. Ran- dom integration of transgene often results in inser- tional mutation which ...Generation of transgenic mice by DNA microinjection has become one of the most important technologies in studying gene function in vivo. Ran- dom integration of transgene often results in inser- tional mutation which may complicate phenotype analysis of transgenic mice and/or create a good opportunity to study the function of endogenous gene. However,the utilization of these potentially valuable resources is hampered due to lack of efficient ap- proaches for rapid identification of multi-copy trans- gene integration sites. Here we propose two PCR-based approaches to identifying trans- gene/genome junction sequences. The efficiency of these two strategies was tested in 9 independent transgenic mouse lines. Among them,the transgene in 8 mouse lines was clearly localized to certain chromosome regions. These rapid and efficient ap- proaches will greatly facilitate the study of insertional mutation due to transgene integration.展开更多
The piggyBac transposable element was suc-cessfully used for generation of the transgenic silkworm, Bombyx mori. The EGFP was adopted in this study as a screening marker in transgenic vector under the control of an ar...The piggyBac transposable element was suc-cessfully used for generation of the transgenic silkworm, Bombyx mori. The EGFP was adopted in this study as a screening marker in transgenic vector under the control of an artificial promoter containing Pax-6 binding sites that can drive eye-specific genes expression in various insect species including B. mori and Drosophila. 111 independent trans-genic lines were obtained among 700 fertile G0 moths. Most of the transgenic lines contained two or more chromosomal insertions of the EGFP marker, which were stably inherited over more than six generations during the time of this pro-ject. PiggyBac-mediated transposition was confirmed by identifying the characteristic TTAA duplication sequence at the insertion sites. The stable and high efficient transmission of a genetic marker into B. mori confirms the usage of this vector-marker system for industrial production and theo-retical research.展开更多
Mitochondrion-localized retinol dehydrogenase 13 (Rdh13) is a short-chain dehydrogenase/reductase involved in vitamin A metabolism in both humans and mice. We previously generated Rdh13 knockout mice and showed that R...Mitochondrion-localized retinol dehydrogenase 13 (Rdh13) is a short-chain dehydrogenase/reductase involved in vitamin A metabolism in both humans and mice. We previously generated Rdh13 knockout mice and showed that Rdh13 deficiency causes severe acute retinal light damage. In this study, considering that Rdh13 is highly expressed in mouse liver, we further evaluated the potential effect of Rdh13 on liver injury induced by carbon tetrachloride (CC14). Although Rdh13 deficiency showed no significant effect on liver histology and physiological functions under regular culture, the Rdh13^-/- mice displayed an attenuated response to CCl4-induced liver injury. Their livers also exhibited less histological changes and contained lower levels of liver-related metabolism enzymes compared with the livers of wild-type (WT) mice. Furthermore, the Rdhl3 1 mice had Rdh13 deficiency and thus their liver cells were protected from apoptosis, and the quantity of their proliferative cells became lower than that in WT after CC14 exposure. The ablation of Rdhl3 gene decreased the expression levels of thyroid hormone-inducible nuclear protein 14 (Spot14) and cytochrome P450 (Cyp2el) in the liver, especially after CC14 treatment for 48 h. These data suggested that the alleviated liver damage induced by CC14 in Rdh13^-/- mice was caused by Cyp2el enzymes, which promoted reductive CC14 metabolism by altering the status of thyroxine metabolism. This result further implicated Rdhl3 as a potential drug target in preventing chemically induced liver injury.展开更多
基金Supported by National Natural Science Fund,No.81270558
文摘AIM: To explore the potential of contrast-enhanced computed tomography(CECT) using Exi Tron nano6000 for assessment of liver lesions in mouse models.METHODS: Three mouse models of liver lesions were used: bile duct ligation(BDL),lipopolysaccharide(LPS)/D-galactosamine(D-Gal N),and alcohol.After injection with the contrast agent Exi Tron nano6000,the mice were scanned with micro-CT.Liver lesions were evaluated using CECT images,hematoxylin and eosin staining,and serum aminotransferase levels.Macrophage distribution in the injury models was shown by immunohistochemical staining of CD68.The in vitro studies measured the densities of RAW264.7 under different conditions by CECT.RESULTS: In the in vitro studies,CECT provided specific and strong contrast enhancement of liver in mice.CECT could present heterogeneous images anddensities of injured livers induced by BDL,LPS/D-Gal N,and alcohol.The liver histology and immunochemistry of CD68 demonstrated that both dilated biliary tracts and necrosis in the injured livers could lead to the heterogeneous distribution of macrophages.The in vitro study showed that the RAW264.7 cell masses had higher densities after LPS activation.CONCLUSION: Micro-CT with the contrast agent Exi Tron nano6000 is feasible for detecting various liver lesions by emphasizing the heterogeneous textures and densities of CECT images.
文摘RIG-I （retinoid acid-inducible gene-I）, a putative RNA helicase with a cytoplasmic caspase-recrultment domain （CARD）, was identified as a pattem-recognition receptor （PRR） that mediates antiviral immunity by inducing type I interferon production. To further study the biological function of RIG-I, we generated Rig-I^-/- mice through homologous recombination, taking a different strategy to the previously reported strategy. Our Rig-I^-/- mice are viable and fertile. Histological analysis shows that Rig-I^-/ mice develop a colitis-like phenotype and increased susceptibility to dextran sulfate sodium-induced colitis. Accordingly, the size and number of Peyer＇s patches dramatically decreased in mutant mice. The peripheral T-cell subsets in mutant mice are characterized by an increase in effector T cells and a decrease in naive T cells, indicating an important role for Rig-I in the regulation ofT-cell activation. It was further found that Rig-I deficiency leads to the downregulation of G protein αi2 subunit （Gαi2） in various tissues, including T and B lymphocytes. By contrast, upregulation of Rig-I in NB4 cells that are treated with ATRA is accompanied by elevated Gαi2 expression. Moreover, Gαi2 promoter activity is increased in co-transfected NIH3T3 cells in a Rig-I dose-dependent manner. All these findings suggest that Rig-I has crucial roles in the regulation of Gαi2 expression and T-cell activation. The development of colitis may be, at least in part, associated with downregulation of Gαi2 and disturbed T-cell homeostasis.
文摘Parthenogenetic embryonic stem （pES） cells provide a valuable in vitro model system for studying the molecular mechanisms that underlie genomic imprinting. However, the pluripotency of pES cells and the expression profiles of paternally expressed imprinted genes have not been fully explored. In this study, three mouse pES cell lines were established and the differentiation potential of these cells in extended culture was evaluated. The undifferentiated cells had a normal karyotype and homozygous genome, and expressed ES-cell-specific molecular markers. The cells remained undifferentiated after more than 50 passages and exhibited pluripotent differentiation capacity. All three lines of the established ES cells produced teratomas; two lines of ES cells produced chimeras and germline transmission. Furthermore, activation of the paternally expressed imprinted genes Snrpn, U2afl-rsl, Peg3, Impact, Zfp127, Dlkl and Mest in these cells was detected. Some paternally expressed imprinted genes were found to be expressed in the blastocyst stage of parthenogenetically activated embryos in vitro and their expression level increased with extended pES cell culture. Furthermore, our data show that the activation of these paternally expressed imprinted genes in pES cells was associated with a change in the methylation of the related differentially methylated regions. These findings provide direct evidence for the pluripotency of pES cells and demonstrate the association between the DNA methylation pattern and the activa- tion of paternally expressed imprinted genes in pES cells. Thus, the established ES cell lines provide a valuable model for studying epigenetic regulation in mammalian development.
基金the grants from Science ＆ Technology Committee of Shanghai Municipality （Grant No. 03DZ14022） the National High Technology Research and Development Program of China （Grant No. 2001AA216081） the National Natural Science Foundation of China for 0utstanding Young Scientists （Grant No. 39925023）.
文摘Generation of transgenic mice by DNA microinjection has become one of the most important technologies in studying gene function in vivo. Ran- dom integration of transgene often results in inser- tional mutation which may complicate phenotype analysis of transgenic mice and/or create a good opportunity to study the function of endogenous gene. However,the utilization of these potentially valuable resources is hampered due to lack of efficient ap- proaches for rapid identification of multi-copy trans- gene integration sites. Here we propose two PCR-based approaches to identifying trans- gene/genome junction sequences. The efficiency of these two strategies was tested in 9 independent transgenic mouse lines. Among them,the transgene in 8 mouse lines was clearly localized to certain chromosome regions. These rapid and efficient ap- proaches will greatly facilitate the study of insertional mutation due to transgene integration.
文摘The piggyBac transposable element was suc-cessfully used for generation of the transgenic silkworm, Bombyx mori. The EGFP was adopted in this study as a screening marker in transgenic vector under the control of an artificial promoter containing Pax-6 binding sites that can drive eye-specific genes expression in various insect species including B. mori and Drosophila. 111 independent trans-genic lines were obtained among 700 fertile G0 moths. Most of the transgenic lines contained two or more chromosomal insertions of the EGFP marker, which were stably inherited over more than six generations during the time of this pro-ject. PiggyBac-mediated transposition was confirmed by identifying the characteristic TTAA duplication sequence at the insertion sites. The stable and high efficient transmission of a genetic marker into B. mori confirms the usage of this vector-marker system for industrial production and theo-retical research.
基金grants from the National Natural Science Foundation of China (No.81430028)the Ministry of Science and Technology of China (No.2011BAI15B02)+1 种基金the grants from the Science and Technology Commission of Shanghai Municipality (Nos.13DZ2280600 and 15DZ2290800)the grant from Shanghai First People's Hospital Affiliated to Shanghai Jiao Tong University (No.81300776).
文摘Mitochondrion-localized retinol dehydrogenase 13 (Rdh13) is a short-chain dehydrogenase/reductase involved in vitamin A metabolism in both humans and mice. We previously generated Rdh13 knockout mice and showed that Rdh13 deficiency causes severe acute retinal light damage. In this study, considering that Rdh13 is highly expressed in mouse liver, we further evaluated the potential effect of Rdh13 on liver injury induced by carbon tetrachloride (CC14). Although Rdh13 deficiency showed no significant effect on liver histology and physiological functions under regular culture, the Rdh13^-/- mice displayed an attenuated response to CCl4-induced liver injury. Their livers also exhibited less histological changes and contained lower levels of liver-related metabolism enzymes compared with the livers of wild-type (WT) mice. Furthermore, the Rdhl3 1 mice had Rdh13 deficiency and thus their liver cells were protected from apoptosis, and the quantity of their proliferative cells became lower than that in WT after CC14 exposure. The ablation of Rdhl3 gene decreased the expression levels of thyroid hormone-inducible nuclear protein 14 (Spot14) and cytochrome P450 (Cyp2el) in the liver, especially after CC14 treatment for 48 h. These data suggested that the alleviated liver damage induced by CC14 in Rdh13^-/- mice was caused by Cyp2el enzymes, which promoted reductive CC14 metabolism by altering the status of thyroxine metabolism. This result further implicated Rdhl3 as a potential drug target in preventing chemically induced liver injury.
