Background Hepatic fibrosis is the key stage of the pathological progress from hepatic injury to cirrhosis. Ursodeoxycholic acid （UDCA） has been known as having significant clinical therapeutic effects on chronic li...Background Hepatic fibrosis is the key stage of the pathological progress from hepatic injury to cirrhosis. Ursodeoxycholic acid （UDCA） has been known as having significant clinical therapeutic effects on chronic liver diseases. Our research aimed to study the effect of UDCA on the signaling pathway of transforming growth factor beta1 （TGFβ1）/Smad and discuss its possible molecular mechanisms of inhibiting hepatic fibrosis. Methods Rat hepatic stellate cells were cultured in vitro and randomly assigned to 4 groups. Group A was control group with only DMEM culture medium applied, and groups B, C, D were experimental groups, with different doses of UDCA （1.0 mmol/L, 0.5 mmol/L and 0.25 mmol/L respectively） added into their DMEM culture medium for further culture of 24 hours and 48 hours. The protein expressions of TGFβ1, TGF type 1 receptor, Smad3, Smad4 and Smad7 were measured by Western blotting, as well as the expressions of TGFβ1, Smad3, Smad7 and cAMP response element （CREB） binding protein （CBP） mRNA by real-time PCR. SPSS 11.5 statistical package was adopted for data analyses. Results Compared with control group, the mRNA expressions of TGFβ1 in the high and middle UDCA dose groups for 24 hours and 48 hours significantly decreased （P 〈0.05）, the protein expressions of TGFβ1 in the two above groups for 48 hours and in the high dose group for 24 hours significantly decreased （P 〈0.05）. The protein and mRNA expressions of Smad3 in each UDCA dose group for 24 hours and 48 hours significantly decreased, with significant difference among different UDCA dose groups and between that of 24 hours and 48 hours observed （P 〈0.05）. The protein and mRNA expressions of Smad7 in the high and middle UDCA dose groups for 24 hours and 48 hours significantly increased. The CBP mRNA expression in each UDCA dose group for 24 hours and 48 hours significantly decreased （P 〈0.05）, with significant difference among different UDCA dose groups observed （P 〈0.05）. Conclusion UDCA could curb the development of hepatic fibrosis through affecting the signaling pathway of TGFβ1/Smad by inhibiting the expressions of TGFβ1, Smad3 and CBP and increasing the expression of Smad7.展开更多
Background Transforming growth factor beta （TGF-beta） plays an essential role in the regulation of normal physiologic processes of cells. TGF-beta has been shown to regulate several mitogen-activated protein kinases...Background Transforming growth factor beta （TGF-beta） plays an essential role in the regulation of normal physiologic processes of cells. TGF-beta has been shown to regulate several mitogen-activated protein kinases （MAPK） pathways in several epithelial cells. However, the effects of TGF-beta on soft tissue sarcoma are seldom reported. Our previous studies suggested that there should be some other signal transduction pathways besides Smads, which are important to regulate the growth of human embryonal rhabdomyosarcoma （RMS） cells. In the present study, we examined the expression and functional relations of extracellular signal-regulated kinase 2 （ERK2） and Smad4 in human RMS tissue and a RMS cell line, RD. Methods RD cells and normal human primary skeletal myoblasts （Mb） were treated with TGF-betal to establish the expression profile of ERK2 at the mRNA and protein levels detected by RT-PCR and immunofluorescence. Immunohistochemistry was used to detect the expression of ERK2 and Smad4 in 50 tissue specimens of human RMS and 23 specimens of normal skeletal muscles. Follow-up of specimens was performed 6 months to 70 months later. Results RD cells and human RMS tissues showed the higher expression of ERK2 and Smad4 than the normal control, either the protein level or the mRNA level. And, exogenous TGF-betal stimulation can lead to higher expression of ERK2 and its nuclear translocation, so TGF-betal can also activatedMAPK （ERK2） pathway, resulting in a sustained activation of ERK2 for at least 2 hours. Immunohistochemistry analysis, however, showed that there was no correlation between ERK2 and Smad4 protein. The overexpression of ERK2 and Smad4 had no indicative effects on histological subtypes, histological grading, gender, age, and prognosis. Conclusions In RMS, signaling of TGF-betal from cell surface to nucleus can also be directed through the MAPK （ERK2） pathway besides the TGF-betal/Smads pathway. The activation of ERK2 by TGF-betal may be Smad4 independent. Moreover, there may be some other tanglesome relationships between the TGF-betal/Smads pathway and the MAPK pathway which takes part in the development, invasion and metastasis of tumor cells.展开更多
文摘Background Hepatic fibrosis is the key stage of the pathological progress from hepatic injury to cirrhosis. Ursodeoxycholic acid （UDCA） has been known as having significant clinical therapeutic effects on chronic liver diseases. Our research aimed to study the effect of UDCA on the signaling pathway of transforming growth factor beta1 （TGFβ1）/Smad and discuss its possible molecular mechanisms of inhibiting hepatic fibrosis. Methods Rat hepatic stellate cells were cultured in vitro and randomly assigned to 4 groups. Group A was control group with only DMEM culture medium applied, and groups B, C, D were experimental groups, with different doses of UDCA （1.0 mmol/L, 0.5 mmol/L and 0.25 mmol/L respectively） added into their DMEM culture medium for further culture of 24 hours and 48 hours. The protein expressions of TGFβ1, TGF type 1 receptor, Smad3, Smad4 and Smad7 were measured by Western blotting, as well as the expressions of TGFβ1, Smad3, Smad7 and cAMP response element （CREB） binding protein （CBP） mRNA by real-time PCR. SPSS 11.5 statistical package was adopted for data analyses. Results Compared with control group, the mRNA expressions of TGFβ1 in the high and middle UDCA dose groups for 24 hours and 48 hours significantly decreased （P 〈0.05）, the protein expressions of TGFβ1 in the two above groups for 48 hours and in the high dose group for 24 hours significantly decreased （P 〈0.05）. The protein and mRNA expressions of Smad3 in each UDCA dose group for 24 hours and 48 hours significantly decreased, with significant difference among different UDCA dose groups and between that of 24 hours and 48 hours observed （P 〈0.05）. The protein and mRNA expressions of Smad7 in the high and middle UDCA dose groups for 24 hours and 48 hours significantly increased. The CBP mRNA expression in each UDCA dose group for 24 hours and 48 hours significantly decreased （P 〈0.05）, with significant difference among different UDCA dose groups observed （P 〈0.05）. Conclusion UDCA could curb the development of hepatic fibrosis through affecting the signaling pathway of TGFβ1/Smad by inhibiting the expressions of TGFβ1, Smad3 and CBP and increasing the expression of Smad7.
基金This work was supported by a grant from China Medical Board of New York(No.CMB 00-722)
文摘Background Transforming growth factor beta （TGF-beta） plays an essential role in the regulation of normal physiologic processes of cells. TGF-beta has been shown to regulate several mitogen-activated protein kinases （MAPK） pathways in several epithelial cells. However, the effects of TGF-beta on soft tissue sarcoma are seldom reported. Our previous studies suggested that there should be some other signal transduction pathways besides Smads, which are important to regulate the growth of human embryonal rhabdomyosarcoma （RMS） cells. In the present study, we examined the expression and functional relations of extracellular signal-regulated kinase 2 （ERK2） and Smad4 in human RMS tissue and a RMS cell line, RD. Methods RD cells and normal human primary skeletal myoblasts （Mb） were treated with TGF-betal to establish the expression profile of ERK2 at the mRNA and protein levels detected by RT-PCR and immunofluorescence. Immunohistochemistry was used to detect the expression of ERK2 and Smad4 in 50 tissue specimens of human RMS and 23 specimens of normal skeletal muscles. Follow-up of specimens was performed 6 months to 70 months later. Results RD cells and human RMS tissues showed the higher expression of ERK2 and Smad4 than the normal control, either the protein level or the mRNA level. And, exogenous TGF-betal stimulation can lead to higher expression of ERK2 and its nuclear translocation, so TGF-betal can also activatedMAPK （ERK2） pathway, resulting in a sustained activation of ERK2 for at least 2 hours. Immunohistochemistry analysis, however, showed that there was no correlation between ERK2 and Smad4 protein. The overexpression of ERK2 and Smad4 had no indicative effects on histological subtypes, histological grading, gender, age, and prognosis. Conclusions In RMS, signaling of TGF-betal from cell surface to nucleus can also be directed through the MAPK （ERK2） pathway besides the TGF-betal/Smads pathway. The activation of ERK2 by TGF-betal may be Smad4 independent. Moreover, there may be some other tanglesome relationships between the TGF-betal/Smads pathway and the MAPK pathway which takes part in the development, invasion and metastasis of tumor cells.
