The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that p...The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed. Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane. This review summarizes recent data on the molecular determinants of this primary bile formation. The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bileduct epithelial cells (cholangiocytes) as bile passes through bile ducts. The mechanisms of fluid and solute transport in cholangiocytes will also be discussed. In contrast to hepatocytes where secretion is constant and poorly controlled, cholangiocyte secretion is regulated by hormones and nerves. A short section dedicated to these regulatory mechanisms of bile secretion has been included. The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology.展开更多
AIM： To elucidate the biological effects of transforming growth factor-β1 （TGF-β1） on intrahepatic cholangiocarcinoma （ICC）.METHODS： We investigated the effects of TGF-β1 on human ICC cell lines （HuCCT1, MEC...AIM： To elucidate the biological effects of transforming growth factor-β1 （TGF-β1） on intrahepatic cholangiocarcinoma （ICC）.METHODS： We investigated the effects of TGF-β1 on human ICC cell lines （HuCCT1, MEC, and HUH-28） by monitoring the influence of TGF-β1 on tumor growth and interleukin-6 （IL-6） expression in ICC cells.RESULTS： All three human ICC cell lines produced TGF-β1 and demonstrated accelerated growth in the presence of TGF-β1 with no apoptotic effect. Studies on HuCCT1 revealed a TGF-β1-induced stimulation of the expression of TGF-β1, as well as a decrease in TGF-β1 mRNA expression induced by neutralizing anti-TGF-β1 antibody. These results indicate that TGF-β1 stimulates the production and function of TGF-β1 in an autocrine fashion. Further, IL-6 secretion was observed in all three cell lines and exhibited an inhibitory response to neutralizing anti-TGF-β1 antibody. Experiments using HuCCT1 revealed a TGF-β1-induced acceleration of IL-6 protein expression and mRNA levels. These findings demonstrate a functional interaction between TGF-β1 and IL-6. All three cell lines proliferated in the presence of IL-6. In contrast, TGF-β1 induced no growth effect in HuCCT1 in the presence of small interfering RNA against a specific cell surface receptor of IL-6 and signal transducer and activator of transcription-3.CONCLUSION： ICC cells produce TGF-β1 and confer a TGF-β1-induced growth effect in an autocrine fashion.TGF-β1 activates ILo6 production, and the functional interaction between TGF-β1 and IL-6 contributes to ICC cell growth by TGF-β1.展开更多
文摘The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed. Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane. This review summarizes recent data on the molecular determinants of this primary bile formation. The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bileduct epithelial cells (cholangiocytes) as bile passes through bile ducts. The mechanisms of fluid and solute transport in cholangiocytes will also be discussed. In contrast to hepatocytes where secretion is constant and poorly controlled, cholangiocyte secretion is regulated by hormones and nerves. A short section dedicated to these regulatory mechanisms of bile secretion has been included. The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology.
基金Supported by the Ministry of Education, Science, Sports, and Culture of Japan, through a Grant-in-Aid for Scientific Research (C)
文摘AIM： To elucidate the biological effects of transforming growth factor-β1 （TGF-β1） on intrahepatic cholangiocarcinoma （ICC）.METHODS： We investigated the effects of TGF-β1 on human ICC cell lines （HuCCT1, MEC, and HUH-28） by monitoring the influence of TGF-β1 on tumor growth and interleukin-6 （IL-6） expression in ICC cells.RESULTS： All three human ICC cell lines produced TGF-β1 and demonstrated accelerated growth in the presence of TGF-β1 with no apoptotic effect. Studies on HuCCT1 revealed a TGF-β1-induced stimulation of the expression of TGF-β1, as well as a decrease in TGF-β1 mRNA expression induced by neutralizing anti-TGF-β1 antibody. These results indicate that TGF-β1 stimulates the production and function of TGF-β1 in an autocrine fashion. Further, IL-6 secretion was observed in all three cell lines and exhibited an inhibitory response to neutralizing anti-TGF-β1 antibody. Experiments using HuCCT1 revealed a TGF-β1-induced acceleration of IL-6 protein expression and mRNA levels. These findings demonstrate a functional interaction between TGF-β1 and IL-6. All three cell lines proliferated in the presence of IL-6. In contrast, TGF-β1 induced no growth effect in HuCCT1 in the presence of small interfering RNA against a specific cell surface receptor of IL-6 and signal transducer and activator of transcription-3.CONCLUSION： ICC cells produce TGF-β1 and confer a TGF-β1-induced growth effect in an autocrine fashion.TGF-β1 activates ILo6 production, and the functional interaction between TGF-β1 and IL-6 contributes to ICC cell growth by TGF-β1.
