BACKGROUND Mesenchymal stem cells(MSCs)exert anti-oncogenic effects via exosomes containing non-coding RNA(ncRNA),which play important roles in tumor biology.Our preliminary study identified the interaction of the ncR...BACKGROUND Mesenchymal stem cells(MSCs)exert anti-oncogenic effects via exosomes containing non-coding RNA(ncRNA),which play important roles in tumor biology.Our preliminary study identified the interaction of the ncRNA hsa_-circ_0000563(circ563)and the circ563-associated miR-148a-3p in exosomes,as miR-148a-3p and its target metal-regulatory transcription factor-1(MTF-1)are implicated in hepatocellular carcinoma(HCC)progression.AIM To identify the clinical significance,functional implications,and mechanisms of circ563 in HCC.METHODS The expression levels of miR-148a-3p and MTF-1 in exosomes derived from MSC and HCC cells were compared,and their effects on HCC cells were assessed.Using a dual-luciferase reporter assay,miR-148a-3p was identified as an associated microRNA of circ563,whose role in HCC regulation was assessed in vitro and in vivo.RESULTS The silencing of circ563 blocked the HCC cell proliferation and invasion and induced apoptosis.Co-culturing of HCC cells with MSC-derived exosomes following circ563 overexpression promoted cell proliferation and metastasis and elicited changes in miR-148a-3p and MTF-1 expression.The tumor-promoting effects of circ563 were partially suppressed by miR-148a-3p overexpression or MTF-1 depletion.Xenograft experiments performed in nude mice confirmed that circ563-enriched exosomes facilitated tumor growth by upregulating the expression of MTF-1.In HCC tissues,circ563 expression was negatively correlated with miR-148a-3p expression but positively correlated with MTF-1 levels.CONCLUSION MSCs may exhibit anti-HCC activity through the exosomal circ563/miR-148a-3p/MTF-1 pathway,while exosomes can transmit circ563 to promote oncogenic behavior by competitively binding to miR-148a-3p to activate MTF-1.展开更多
POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem （ES） cells but also acts as a cell fate determinant through a gene dosage effec...POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem （ES） cells but also acts as a cell fate determinant through a gene dosage effect. However, the molecular mechanisms that control the intracellular OCT4 protein level remain elusive. Here, we report that human WWP2, an E3 ubiquitin （Ub）-protein ligase, interacts with OCT4 specifically through its WW domain and enhances Ub modification of OCT4 both in vitro and in vivo. We first demonstrated that endogenous OCT4 in hu- man ES cells can be post-translationally modified by Ub. Furthermore, we found that WWP2 promoted degradation of OCT4 through the 26S proteasome in a dosage-dependent manner, and the active site cysteine residue of WWP2 was required for both its enzymatic activity and proteolytic effect on OCT4. Remarkably, our data show that the en- dogenous OCT4 protein level was significantly elevated when WWP2 expression was downregulated by specific RNA interference （RNAi）, suggesting that WWP2 is an important regulator for maintaining a proper OCT4 protein level in human ES cells. Moreover, northern blot analysis showed that the WWP2 transcript was widely present in diverse human tissues/organs and highly expressed in undifferentiated human ES cells. However, its expression level was quickly decreased after human ES cells differentiated, indicating that WWP2 expression might be developmentally regulated. Our findings demonstrate that WWP2 is an important regulator of the OCT4 protein level in human ES cells.展开更多
OBJECTIVE To investigate the correlations between the expression of thyroid transcription factor-1 （TTF-1） and apoptosis and angiogenesis in lung carcinomas. METHODS A 829 microarray of the paraffin tissue chips was...OBJECTIVE To investigate the correlations between the expression of thyroid transcription factor-1 （TTF-1） and apoptosis and angiogenesis in lung carcinomas. METHODS A 829 microarray of the paraffin tissue chips was constructed, which contained 196 lung carcinomas, 10 normal lung tissues, and 1 muscular tissue. Terminal deoxynucleotidyl transferase mediated nick end labeling （TUNEL） and immunohistochemical SP method were used to detect apoptosis and expression of TTF-1 and CD34 in different types of lung carcinomas. A Leica Q500 MC image analysis system was used to measure and calculate TTF-1 positive unit （PU）, apoptotic index （AI） and microvessel density （MVD）. RESULTS AI of lung small cell carcinoma and large cell carcinoma were smaller than those of lung adenocarcinoma and squamous cell carcinoma （P = 0.000）. AI of lung carcinomas with lymph node metastases was smaller than that of those without （P = 0.039）. AI of lung carcinomas in TNM stage I-IV was smaller than that in stage I （P = 0.008）. The PU of the TTF-1 was negatively correlated with AI in small cell lung carcinoma （r = -0.752, P = 0.000）. MVD of lung carcinomas without lymph node metastases was smaller than that of those with lymph node metastasis （P = 0.031）. MVD of lung carcinomas in TNM stage I was smaller than that in stage I-IV （P = 0.040）. The PU of TTF-1 was positively correlated with MVD in lung adenocarcinoma （r = 0.708, P = 0.000）. CONCLUSION There is a negative correlation between TTF-1 PU and AI in small cell lung carcinoma. TTF-1 PU and AI may be correlated with each other. There is a positive correlation between TTF-1 PU and MVD in lung adenocarcinoma. TTF-1 may induce the development of lung adenocarcinoma by inducing tumor angiogenesis.展开更多
Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key do...Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.展开更多
目的:探究溴结构域蛋白4(bromodomain-containing protein 4,BRD4)在心肌梗死后心脏损伤中的作用。方法:通过分析公共数据,明确心肌梗死小鼠心脏组织中BRD4在整体和以及各细胞群中的表达变化。构建心肌梗死小鼠模型,设立空白对照组(WT...目的:探究溴结构域蛋白4(bromodomain-containing protein 4,BRD4)在心肌梗死后心脏损伤中的作用。方法:通过分析公共数据,明确心肌梗死小鼠心脏组织中BRD4在整体和以及各细胞群中的表达变化。构建心肌梗死小鼠模型,设立空白对照组(WT组),心肌梗死组(MI组),药物组(JQ1组,ABBV-744组),术后第6天腹腔注射BRD4抑制剂JQ1或灌胃二代抑制剂ABBV-744,持续22天。MI术后4周,小动物超声影像系统检测小鼠心功能,检测小鼠质量、心脏质量与胫骨长度,天狼星红染色评估梗死区纤维化程度,WGA染色检测心肌细胞横截面积。结果:与心肌梗死组相比,BRD4抑制剂组能够显著改善术后心功能障碍(P<0.01)。转录组学数据表明,BRD4在心肌梗死损伤区域持续高表达。单细胞数据显示,心肌梗死后,成纤维细胞中BRD4阳性细胞比例显著增加,并且在心肌梗死后7、14、30d的成纤维细胞中,BRD4表达持续上调。与心肌梗死组相比,BRD4抑制剂组显著减轻心脏纤维化(P <0.01)。与一代药物组相比,二代药物组心脏纤维化程度显著降低(P<0.01)。结论:抑制表观转录因子BRD4可减轻心肌梗死后心脏损伤,抑制心脏纤维化,并改善心功能。展开更多
Increased accumulation and/or impaired utilization of fatty acid in extra-adipose tissues are implicated in the pathogenesis of insulin resistance and type 2 diabetes. Pyruvate dehydrogenase kinase 4 （Pdk4） is a key...Increased accumulation and/or impaired utilization of fatty acid in extra-adipose tissues are implicated in the pathogenesis of insulin resistance and type 2 diabetes. Pyruvate dehydrogenase kinase 4 （Pdk4） is a key enzyme involved in fatty oxidation and energy expenditure, and its expression can be repressed by pro-inflammatory stimuli. Previously, we have shown that class II transactivator （CIITA） mediates the adverse effect of interferon gamma （IFN-7） in skeletal muscle cells by cooperating with hypermethylated in cancer 1 （HIC1） to repress silent informa- tion regulator 1 （SIRT1） transcription. Building upon this finding, we report here that CIITA interacted with HIC1 via the GTP-binding domain （GBD） while HIC1 interacted with CIITA via the BTB/POZ domain. The GBD domain was required for CIITA to repress SIRT1 transcription probably acting as a bridge for CIITA to bind to HIC1 and consequently to bind to the SIRT1 promoter. IFN-7 stimulation, CIITA over-expression, or HIC1 over- expression repressed Pdk4 promoter activity while silencing either CIITA or HIC1 normalized Pdk4 expression in the presence of IFN-7. An increase in SIRT1 expression or activity partially rescued Pdk4 expression in the pre- sence of CIITA, but SIRT1 inhibition abrogated Pdk4 normalization even in the absence of CIITA. Taken together, our data have identified a HIC1-CIITA-SIRT1 axis that regulates Pdk4 transcription in response to IFN-7 stimula- tion.展开更多
The Janus kinase and signal transducer and activator of transcription （JAK/STAT） signal transduction pathway is involved in sepsis-induced functional damage to the heart, liver, kidney, and other organs. However, th...The Janus kinase and signal transducer and activator of transcription （JAK/STAT） signal transduction pathway is involved in sepsis-induced functional damage to the heart, liver, kidney, and other organs. However, the cellular and molecular mechanisms underlying sepsis-induced brain damage remain elusive. In the present study, we found severe loss of neurons in the hippocampal CA1 region in rats with sepsis-induced brain damage following intraperitoneal injection of endotoxin, The expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 was significantly increased in brain tissues following lipopolysaccharide exposure. AG490 （JAK2 antagonist） and rapamycin （STAT3 antagonist） significantly reduced neuronal loss and suppressed the increased expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 in the hippocampal CA1 region in sepsis-induced brain damaged rats. Overall, these data suggest that blockade of the JAK/STAT signal transduction pathway is neuroprotective in sepsis-induced brain damage via the inhibition of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 exoression.展开更多
基金the National Natural Science Foundation of China,No.81972606 and 82271774.
文摘BACKGROUND Mesenchymal stem cells(MSCs)exert anti-oncogenic effects via exosomes containing non-coding RNA(ncRNA),which play important roles in tumor biology.Our preliminary study identified the interaction of the ncRNA hsa_-circ_0000563(circ563)and the circ563-associated miR-148a-3p in exosomes,as miR-148a-3p and its target metal-regulatory transcription factor-1(MTF-1)are implicated in hepatocellular carcinoma(HCC)progression.AIM To identify the clinical significance,functional implications,and mechanisms of circ563 in HCC.METHODS The expression levels of miR-148a-3p and MTF-1 in exosomes derived from MSC and HCC cells were compared,and their effects on HCC cells were assessed.Using a dual-luciferase reporter assay,miR-148a-3p was identified as an associated microRNA of circ563,whose role in HCC regulation was assessed in vitro and in vivo.RESULTS The silencing of circ563 blocked the HCC cell proliferation and invasion and induced apoptosis.Co-culturing of HCC cells with MSC-derived exosomes following circ563 overexpression promoted cell proliferation and metastasis and elicited changes in miR-148a-3p and MTF-1 expression.The tumor-promoting effects of circ563 were partially suppressed by miR-148a-3p overexpression or MTF-1 depletion.Xenograft experiments performed in nude mice confirmed that circ563-enriched exosomes facilitated tumor growth by upregulating the expression of MTF-1.In HCC tissues,circ563 expression was negatively correlated with miR-148a-3p expression but positively correlated with MTF-1 levels.CONCLUSION MSCs may exhibit anti-HCC activity through the exosomal circ563/miR-148a-3p/MTF-1 pathway,while exosomes can transmit circ563 to promote oncogenic behavior by competitively binding to miR-148a-3p to activate MTF-1.
基金Acknowledgments We are grateful to Dr DA Melton （Harvard University） for shar- ing his human ES cells with us. The study was supported by grants from the National High Technology Research and Development Program of China （2006CB943900）, the National Natural Science Foundation of China （General Program, 30500088）, the Shang- hai Jiao Tong University School of Medicine, and the Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. The study was also supported by the Shanghai Leading Academic Deciline Project （S30201）.
文摘POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem （ES） cells but also acts as a cell fate determinant through a gene dosage effect. However, the molecular mechanisms that control the intracellular OCT4 protein level remain elusive. Here, we report that human WWP2, an E3 ubiquitin （Ub）-protein ligase, interacts with OCT4 specifically through its WW domain and enhances Ub modification of OCT4 both in vitro and in vivo. We first demonstrated that endogenous OCT4 in hu- man ES cells can be post-translationally modified by Ub. Furthermore, we found that WWP2 promoted degradation of OCT4 through the 26S proteasome in a dosage-dependent manner, and the active site cysteine residue of WWP2 was required for both its enzymatic activity and proteolytic effect on OCT4. Remarkably, our data show that the en- dogenous OCT4 protein level was significantly elevated when WWP2 expression was downregulated by specific RNA interference （RNAi）, suggesting that WWP2 is an important regulator for maintaining a proper OCT4 protein level in human ES cells. Moreover, northern blot analysis showed that the WWP2 transcript was widely present in diverse human tissues/organs and highly expressed in undifferentiated human ES cells. However, its expression level was quickly decreased after human ES cells differentiated, indicating that WWP2 expression might be developmentally regulated. Our findings demonstrate that WWP2 is an important regulator of the OCT4 protein level in human ES cells.
文摘OBJECTIVE To investigate the correlations between the expression of thyroid transcription factor-1 （TTF-1） and apoptosis and angiogenesis in lung carcinomas. METHODS A 829 microarray of the paraffin tissue chips was constructed, which contained 196 lung carcinomas, 10 normal lung tissues, and 1 muscular tissue. Terminal deoxynucleotidyl transferase mediated nick end labeling （TUNEL） and immunohistochemical SP method were used to detect apoptosis and expression of TTF-1 and CD34 in different types of lung carcinomas. A Leica Q500 MC image analysis system was used to measure and calculate TTF-1 positive unit （PU）, apoptotic index （AI） and microvessel density （MVD）. RESULTS AI of lung small cell carcinoma and large cell carcinoma were smaller than those of lung adenocarcinoma and squamous cell carcinoma （P = 0.000）. AI of lung carcinomas with lymph node metastases was smaller than that of those without （P = 0.039）. AI of lung carcinomas in TNM stage I-IV was smaller than that in stage I （P = 0.008）. The PU of the TTF-1 was negatively correlated with AI in small cell lung carcinoma （r = -0.752, P = 0.000）. MVD of lung carcinomas without lymph node metastases was smaller than that of those with lymph node metastasis （P = 0.031）. MVD of lung carcinomas in TNM stage I was smaller than that in stage I-IV （P = 0.040）. The PU of TTF-1 was positively correlated with MVD in lung adenocarcinoma （r = 0.708, P = 0.000）. CONCLUSION There is a negative correlation between TTF-1 PU and AI in small cell lung carcinoma. TTF-1 PU and AI may be correlated with each other. There is a positive correlation between TTF-1 PU and MVD in lung adenocarcinoma. TTF-1 may induce the development of lung adenocarcinoma by inducing tumor angiogenesis.
基金supported by the Start-up Funding of Henan University of Science and Technology(13480027) to Q. C.the Key Science Foundation of Nanjing Medical University(2015NJMUZD002)+2 种基金the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(16KJB-180020)Natural Science Foundation of Jiangsu Province (BK20171053)National Natural Science Funds of China (81702747) to C.L
文摘Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.
文摘目的:探究溴结构域蛋白4(bromodomain-containing protein 4,BRD4)在心肌梗死后心脏损伤中的作用。方法:通过分析公共数据,明确心肌梗死小鼠心脏组织中BRD4在整体和以及各细胞群中的表达变化。构建心肌梗死小鼠模型,设立空白对照组(WT组),心肌梗死组(MI组),药物组(JQ1组,ABBV-744组),术后第6天腹腔注射BRD4抑制剂JQ1或灌胃二代抑制剂ABBV-744,持续22天。MI术后4周,小动物超声影像系统检测小鼠心功能,检测小鼠质量、心脏质量与胫骨长度,天狼星红染色评估梗死区纤维化程度,WGA染色检测心肌细胞横截面积。结果:与心肌梗死组相比,BRD4抑制剂组能够显著改善术后心功能障碍(P<0.01)。转录组学数据表明,BRD4在心肌梗死损伤区域持续高表达。单细胞数据显示,心肌梗死后,成纤维细胞中BRD4阳性细胞比例显著增加,并且在心肌梗死后7、14、30d的成纤维细胞中,BRD4表达持续上调。与心肌梗死组相比,BRD4抑制剂组显著减轻心脏纤维化(P <0.01)。与一代药物组相比,二代药物组心脏纤维化程度显著降低(P<0.01)。结论:抑制表观转录因子BRD4可减轻心肌梗死后心脏损伤,抑制心脏纤维化,并改善心功能。
基金supported,in part,by the National Natural Science Foundation of China(31200645)the Natural Science Foundation of Jiangsu Province(BK20141498)a grant from Jiangsu Jiankang Vocational University(JK201405)
文摘Increased accumulation and/or impaired utilization of fatty acid in extra-adipose tissues are implicated in the pathogenesis of insulin resistance and type 2 diabetes. Pyruvate dehydrogenase kinase 4 （Pdk4） is a key enzyme involved in fatty oxidation and energy expenditure, and its expression can be repressed by pro-inflammatory stimuli. Previously, we have shown that class II transactivator （CIITA） mediates the adverse effect of interferon gamma （IFN-7） in skeletal muscle cells by cooperating with hypermethylated in cancer 1 （HIC1） to repress silent informa- tion regulator 1 （SIRT1） transcription. Building upon this finding, we report here that CIITA interacted with HIC1 via the GTP-binding domain （GBD） while HIC1 interacted with CIITA via the BTB/POZ domain. The GBD domain was required for CIITA to repress SIRT1 transcription probably acting as a bridge for CIITA to bind to HIC1 and consequently to bind to the SIRT1 promoter. IFN-7 stimulation, CIITA over-expression, or HIC1 over- expression repressed Pdk4 promoter activity while silencing either CIITA or HIC1 normalized Pdk4 expression in the presence of IFN-7. An increase in SIRT1 expression or activity partially rescued Pdk4 expression in the pre- sence of CIITA, but SIRT1 inhibition abrogated Pdk4 normalization even in the absence of CIITA. Taken together, our data have identified a HIC1-CIITA-SIRT1 axis that regulates Pdk4 transcription in response to IFN-7 stimula- tion.
文摘The Janus kinase and signal transducer and activator of transcription （JAK/STAT） signal transduction pathway is involved in sepsis-induced functional damage to the heart, liver, kidney, and other organs. However, the cellular and molecular mechanisms underlying sepsis-induced brain damage remain elusive. In the present study, we found severe loss of neurons in the hippocampal CA1 region in rats with sepsis-induced brain damage following intraperitoneal injection of endotoxin, The expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 was significantly increased in brain tissues following lipopolysaccharide exposure. AG490 （JAK2 antagonist） and rapamycin （STAT3 antagonist） significantly reduced neuronal loss and suppressed the increased expression of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 in the hippocampal CA1 region in sepsis-induced brain damaged rats. Overall, these data suggest that blockade of the JAK/STAT signal transduction pathway is neuroprotective in sepsis-induced brain damage via the inhibition of toll-like receptor 4, tumor necrosis factor a, and interleukin-6 exoression.
