目的ATP结合盒B亚家族成员1(ATP binding cassette subfamily B member 1,ABCB1)的异常表达在多种癌症的发生发展中发挥关键作用。然而,G蛋白偶联受体C家族5组A型(G protein coupled receptor family C group5 type A,GPRC5A)调控的ABCB...目的ATP结合盒B亚家族成员1(ATP binding cassette subfamily B member 1,ABCB1)的异常表达在多种癌症的发生发展中发挥关键作用。然而,G蛋白偶联受体C家族5组A型(G protein coupled receptor family C group5 type A,GPRC5A)调控的ABCB1表达对肺腺癌增殖的影响仍不清楚。本研究探讨了GPRC5A调控的ABCB1表达对肺腺癌增殖的影响。方法我们采用RT-PCR、Western-blot或免疫组化实验,分析ABCB1在肺腺癌细胞系、人肺腺癌组织以及GPRC5A基因敲除小鼠和野生型小鼠的气管上皮细胞和肺组织中的表达。采用细胞计数试剂盒-8(CCK-8)分析GPRC5A基因敲除小鼠气管上皮细胞对化疗药物的敏感性。采用皮下肿瘤形成实验探讨下调ABCB1表达是否可抑制体内肺腺癌增殖。采用免疫荧光和免疫沉淀实验研究GPRC5A和ABCB1之间潜在的调控关系。结果ABCB1在肺腺癌细胞系和人类肺腺癌组织中表达上调。GPRC5A基因敲除小鼠的气管上皮细胞及肺组织的ABCB1表达高于野生型小鼠。与GPRC5A野生型小鼠的气管上皮细胞相比,GPRC5A基因敲除小鼠的气管上皮细胞对塔立奇达和多柔比星更敏感。注射移植细胞28天后,接受ABCB1基因敲除细胞移植的GPRC5A-/-C57BL/6小鼠的肺肿瘤的体积和重量均明显低于野生型细胞移植小鼠(P=0.0043,P=0.0060)。此外,免疫荧光和免疫沉淀实验表明,GPRC5A通过直接结合方式调控ABCB1的表达。结论GPRC5A通过抑制ABCB1表达降低肺腺癌增殖。GPRC5A调节ABCB1表达的途径有待研究。展开更多
BACKGROUND Benign recurrent intrahepatic cholestasis is a genetic disorder with recurrent cholestatic jaundice due to ATP8B1 and ABCB11 gene mutations encoding for hepato-canalicular transporters.Herein,we firstly pro...BACKGROUND Benign recurrent intrahepatic cholestasis is a genetic disorder with recurrent cholestatic jaundice due to ATP8B1 and ABCB11 gene mutations encoding for hepato-canalicular transporters.Herein,we firstly provide the evidence that a nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygous form is involved in BRIC pathogenesis.CASE SUMMARY A 29-year-old male showed severe jaundice and laboratory tests consistent with intrahepatic cholestasis despite normal gamma-glutamyltranspeptidase.Acute and chronic liver diseases with viral,metabolic and autoimmune etiology were excluded.Normal intra/extra-hepatic bile ducts were demonstrated by magnetic resonance.Liver biopsy showed:Cholestasis in the centrilobular and intermediate zones with bile plugs and intra-hepatocyte pigment,Kupffer’s cell activation/hyperplasia and preserved biliary ducts.Being satisfied benign recurrent intrahepatic cholestasis diagnostic criteria,ATP8B1 and ABCB11 gene analysis was performed.Surprisingly,we found a novel nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygosis.The variant was confirmed by Sanger sequencing following a standard protocol and tested for familial segregation,showing a maternal inheritance.Immunohistochemistry confirmed a significant reduction of mutated gene related protein(familial intrahepatic cholestasis 1).The patient was treated with ursodeoxycholic acid 15 mg/kg per day and colestyramine 8 g daily with total bilirubin decrease and normalization at the 6th and 12th mo.CONCLUSION A genetic abnormality,different from those already known,could be involved in familial intrahepatic cholestatic disorders and/or pro-cholestatic genetic predisposition,thus encouraging further mutation detection in this field.展开更多
Recent reports in patients with PFIC1 have indicated that a gene defect in ATP8B1 could cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. This study aimed to:(1) define...Recent reports in patients with PFIC1 have indicated that a gene defect in ATP8B1 could cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. This study aimed to:(1) define ATP8B1 expression in human hepatobiliary cell types, and (2) determine whether ATP8B1 defect affects gene expressions related to bile secretion in these cells. ATP8B1 expression was detected by RT-PCR in hepatocytes and cholangiocytes isolated from normal human liver and gallbladder. ATP8B1 mRNA levels were 20-and 200-fold higher in bile duct and gallbladder epithelial cells, respectively, than in hepatocytes. RT-PCR analyses of the liver from two patients with PFIC1, one with PFIC2, one with biliary atresia, showed that, compared to normal liver, hepatic expressions of FXR, SHP, CYP7A1, ASBT were decreased at least by 90%in all cholestatic disorders. In contrast, NTCP transcripts were less decreased(by ≤30%vs. 97%) in PFIC1 as compared with other cholestatic disorders, while BSEP transcripts, in agreement with BSEP immunohistochemical signals, were normal or less decreased(by 50%vs. 97%). CFTR hepatic expression was decreased(by 80%), exclusively in PFIC1, while bile duct mass was not reduced, as ascertained by cytokeratin-19 immunolabeling. In Mz-ChA-2 human biliary epithelial cells, a significant decrease in CFTR expression was associated with ATP8B1 invalidation by siRNA. In conclusion, cholangiocytes are a major site of ATP8B1 hepatobiliary expression. A defect of ATP8B1 along with CFTR downregulation can impair the contribution of these cells to bile secretion, and potentially explain the extrahepatic cystic fibrosis-like manifestations that occur in PFIC1.展开更多
Background: Intrahepatic cholestasis of pregnancy (ICP) affects approximately 0.7%of pregnancies in the UK and is associated with prematurity, fetal distress, and intrauterine death. Homozygous mutations in the ATP8B1...Background: Intrahepatic cholestasis of pregnancy (ICP) affects approximately 0.7%of pregnancies in the UK and is associated with prematurity, fetal distress, and intrauterine death. Homozygous mutations in the ATP8B1 gene cause cholestasis with a normal serum gamma-glutamyl transpeptidase (γ-GT), and have been reported in two forms of cholestasis: progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis (BRIC). Aims: To establish whether mutations in ATP8B1 are associated with ICP in British cases. Patients: Sixteen well phenotyped women with ICP without raised γ-GT were selected for sequence analysis. Subsequently, 182 patients and 120 controls were examined for the presence of the variants detected. Methods: All coding exons were sequenced in 16 cases. Eight ICP cases, including two women carrying a mutation, were investigated using in vivo hepatic 31P magnetic resonance spectroscopy (MRS). Results: Two heterozygous ATP8B1 transitions (208G >A and 2599C >T) that resulted in amino acid substitutions were identified; 208G >A was identified in three cases. MRS revealed an increased phosphodiester signal (Mann-Whitney U test, p = 0.03) and a decreased phosphomonoester/phosphodiester ratio (p = 0.04) in ICP cases compared with controls. Conclusions: We were able to demonstrate ATP8B1 mutations in ICP. MRS studies suggest that susceptibility to ICP is associated with a relative rise in biliary phospholipid. These data also suggest that MRS may be used for non-invasive assessment of the liver and biliary constituents in cholestasis.展开更多
Cholestasis is a clinical condition resulting from the imapairment of bile flow.This condition could be caused by defects of the hepatocytes,which are responsible for the complex process of bile formation and secretio...Cholestasis is a clinical condition resulting from the imapairment of bile flow.This condition could be caused by defects of the hepatocytes,which are responsible for the complex process of bile formation and secretion,and/or caused by defects in the secretory machinery of cholangiocytes.Several mutations and pathways that lead to cholestasis have been described.Progressive familial intrahepatic cholestasis(PFIC)is a group of rare diseases caused by autosomal recessive mutations in the genes that encode proteins expressed mainly in the apical membrane of the hepatocytes.PFIC 1,also known as Byler’s disease,is caused by mutations of the ATP8B1 gene,which encodes the familial intrahepatic cholestasis 1 protein.PFIC 2 is characterized by the downregulation or absence of functional bile salt export pump(BSEP)expression via variations in the ABCB11 gene.Mutations of the ABCB4 gene result in lower expression of the multidrug resistance class 3 glycoprotein,leading to the third type of PFIC.Newer variations of this disease have been described.Loss of function of the tight junction protein 2 protein results in PFIC 4,while mutations of the NR1H4 gene,which encodes farnesoid X receptor,an important transcription factor for bile formation,cause PFIC 5.A recently described type of PFIC is associated with a mutation in the MYO5B gene,important for the trafficking of BSEP and hepatocyte membrane polarization.In this review,we provide a brief overview of the molecular mechanisms and clinical features associated with each type of PFIC based on peer reviewed journals published between 1993 and 2020.展开更多
Familial intrahepatic cholestasis(FIC) comprises a group of rare cholestatic liver diseases associated with canalicular transport defects resulting predominantly from mutations in ATP8B1, ABCB11 and ABCB4. Phe-notypes...Familial intrahepatic cholestasis(FIC) comprises a group of rare cholestatic liver diseases associated with canalicular transport defects resulting predominantly from mutations in ATP8B1, ABCB11 and ABCB4. Phe-notypes range from benign recurrent intrahepatic cholestasis(BRIC), associated with recurrent cholestatic attacks, to progressive FIC(PFIC). Patients often suffer from severe pruritus and eventually progressive cholestasis results in liver failure. Currently, first-line treatment includes ursodeoxycholic acid in patients with ABCB4 deficiency(PFIC3) and partial biliary diversion in patients with ATP8B1 or ABCB11 deficiency(PFIC1 and PFIC2). When treatment fails, liver transplantation is needed which is associated with complications like rejection, post-transplant hepatic steatosis and recurrence of disease. Therefore, the need for more and better therapies for this group of chronic diseases remains. Here, we discuss new symptomatic treatment options like total biliary diversion, pharmacological diversion of bile acids and hepatocyte transplantation. Furthermore, we focus on emerging mutation-targeted therapeutic strategies, providing an outlook for future personalized treatment for inherited cholestatic liver diseases.展开更多
Benign recurrent intrahepatic cholestasis （BRIC） is a Prare autosomal recessive liver disease characterizedby intermittent attacks of cholestasis that was first reported by Summerskill and Walshe in 1959.1 A few rep...Benign recurrent intrahepatic cholestasis （BRIC） is a Prare autosomal recessive liver disease characterizedby intermittent attacks of cholestasis that was first reported by Summerskill and Walshe in 1959.1 A few reports on patients with BRIC in China have been described in recent years, however, it is still a challenge to give the patients a correct diagnosis. Therefore, we collected five cases in the Beijing Friendship Hospital and the China-Japan Friendship Hospital in the past two years to summarize their clinical features, and explore the mutation region of the ATP8B1 gene from Chinese patients with BRIC.展开更多
文摘目的ATP结合盒B亚家族成员1(ATP binding cassette subfamily B member 1,ABCB1)的异常表达在多种癌症的发生发展中发挥关键作用。然而,G蛋白偶联受体C家族5组A型(G protein coupled receptor family C group5 type A,GPRC5A)调控的ABCB1表达对肺腺癌增殖的影响仍不清楚。本研究探讨了GPRC5A调控的ABCB1表达对肺腺癌增殖的影响。方法我们采用RT-PCR、Western-blot或免疫组化实验,分析ABCB1在肺腺癌细胞系、人肺腺癌组织以及GPRC5A基因敲除小鼠和野生型小鼠的气管上皮细胞和肺组织中的表达。采用细胞计数试剂盒-8(CCK-8)分析GPRC5A基因敲除小鼠气管上皮细胞对化疗药物的敏感性。采用皮下肿瘤形成实验探讨下调ABCB1表达是否可抑制体内肺腺癌增殖。采用免疫荧光和免疫沉淀实验研究GPRC5A和ABCB1之间潜在的调控关系。结果ABCB1在肺腺癌细胞系和人类肺腺癌组织中表达上调。GPRC5A基因敲除小鼠的气管上皮细胞及肺组织的ABCB1表达高于野生型小鼠。与GPRC5A野生型小鼠的气管上皮细胞相比,GPRC5A基因敲除小鼠的气管上皮细胞对塔立奇达和多柔比星更敏感。注射移植细胞28天后,接受ABCB1基因敲除细胞移植的GPRC5A-/-C57BL/6小鼠的肺肿瘤的体积和重量均明显低于野生型细胞移植小鼠(P=0.0043,P=0.0060)。此外,免疫荧光和免疫沉淀实验表明,GPRC5A通过直接结合方式调控ABCB1的表达。结论GPRC5A通过抑制ABCB1表达降低肺腺癌增殖。GPRC5A调节ABCB1表达的途径有待研究。
文摘BACKGROUND Benign recurrent intrahepatic cholestasis is a genetic disorder with recurrent cholestatic jaundice due to ATP8B1 and ABCB11 gene mutations encoding for hepato-canalicular transporters.Herein,we firstly provide the evidence that a nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygous form is involved in BRIC pathogenesis.CASE SUMMARY A 29-year-old male showed severe jaundice and laboratory tests consistent with intrahepatic cholestasis despite normal gamma-glutamyltranspeptidase.Acute and chronic liver diseases with viral,metabolic and autoimmune etiology were excluded.Normal intra/extra-hepatic bile ducts were demonstrated by magnetic resonance.Liver biopsy showed:Cholestasis in the centrilobular and intermediate zones with bile plugs and intra-hepatocyte pigment,Kupffer’s cell activation/hyperplasia and preserved biliary ducts.Being satisfied benign recurrent intrahepatic cholestasis diagnostic criteria,ATP8B1 and ABCB11 gene analysis was performed.Surprisingly,we found a novel nonsense variant of ATP8B1 gene(c.1558A>T)in heterozygosis.The variant was confirmed by Sanger sequencing following a standard protocol and tested for familial segregation,showing a maternal inheritance.Immunohistochemistry confirmed a significant reduction of mutated gene related protein(familial intrahepatic cholestasis 1).The patient was treated with ursodeoxycholic acid 15 mg/kg per day and colestyramine 8 g daily with total bilirubin decrease and normalization at the 6th and 12th mo.CONCLUSION A genetic abnormality,different from those already known,could be involved in familial intrahepatic cholestatic disorders and/or pro-cholestatic genetic predisposition,thus encouraging further mutation detection in this field.
文摘Recent reports in patients with PFIC1 have indicated that a gene defect in ATP8B1 could cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. This study aimed to:(1) define ATP8B1 expression in human hepatobiliary cell types, and (2) determine whether ATP8B1 defect affects gene expressions related to bile secretion in these cells. ATP8B1 expression was detected by RT-PCR in hepatocytes and cholangiocytes isolated from normal human liver and gallbladder. ATP8B1 mRNA levels were 20-and 200-fold higher in bile duct and gallbladder epithelial cells, respectively, than in hepatocytes. RT-PCR analyses of the liver from two patients with PFIC1, one with PFIC2, one with biliary atresia, showed that, compared to normal liver, hepatic expressions of FXR, SHP, CYP7A1, ASBT were decreased at least by 90%in all cholestatic disorders. In contrast, NTCP transcripts were less decreased(by ≤30%vs. 97%) in PFIC1 as compared with other cholestatic disorders, while BSEP transcripts, in agreement with BSEP immunohistochemical signals, were normal or less decreased(by 50%vs. 97%). CFTR hepatic expression was decreased(by 80%), exclusively in PFIC1, while bile duct mass was not reduced, as ascertained by cytokeratin-19 immunolabeling. In Mz-ChA-2 human biliary epithelial cells, a significant decrease in CFTR expression was associated with ATP8B1 invalidation by siRNA. In conclusion, cholangiocytes are a major site of ATP8B1 hepatobiliary expression. A defect of ATP8B1 along with CFTR downregulation can impair the contribution of these cells to bile secretion, and potentially explain the extrahepatic cystic fibrosis-like manifestations that occur in PFIC1.
文摘Background: Intrahepatic cholestasis of pregnancy (ICP) affects approximately 0.7%of pregnancies in the UK and is associated with prematurity, fetal distress, and intrauterine death. Homozygous mutations in the ATP8B1 gene cause cholestasis with a normal serum gamma-glutamyl transpeptidase (γ-GT), and have been reported in two forms of cholestasis: progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis (BRIC). Aims: To establish whether mutations in ATP8B1 are associated with ICP in British cases. Patients: Sixteen well phenotyped women with ICP without raised γ-GT were selected for sequence analysis. Subsequently, 182 patients and 120 controls were examined for the presence of the variants detected. Methods: All coding exons were sequenced in 16 cases. Eight ICP cases, including two women carrying a mutation, were investigated using in vivo hepatic 31P magnetic resonance spectroscopy (MRS). Results: Two heterozygous ATP8B1 transitions (208G >A and 2599C >T) that resulted in amino acid substitutions were identified; 208G >A was identified in three cases. MRS revealed an increased phosphodiester signal (Mann-Whitney U test, p = 0.03) and a decreased phosphomonoester/phosphodiester ratio (p = 0.04) in ICP cases compared with controls. Conclusions: We were able to demonstrate ATP8B1 mutations in ICP. MRS studies suggest that susceptibility to ICP is associated with a relative rise in biliary phospholipid. These data also suggest that MRS may be used for non-invasive assessment of the liver and biliary constituents in cholestasis.
基金Supported by NIH,No.UG3TR003289 to Soto-Gutierrez A.
文摘Cholestasis is a clinical condition resulting from the imapairment of bile flow.This condition could be caused by defects of the hepatocytes,which are responsible for the complex process of bile formation and secretion,and/or caused by defects in the secretory machinery of cholangiocytes.Several mutations and pathways that lead to cholestasis have been described.Progressive familial intrahepatic cholestasis(PFIC)is a group of rare diseases caused by autosomal recessive mutations in the genes that encode proteins expressed mainly in the apical membrane of the hepatocytes.PFIC 1,also known as Byler’s disease,is caused by mutations of the ATP8B1 gene,which encodes the familial intrahepatic cholestasis 1 protein.PFIC 2 is characterized by the downregulation or absence of functional bile salt export pump(BSEP)expression via variations in the ABCB11 gene.Mutations of the ABCB4 gene result in lower expression of the multidrug resistance class 3 glycoprotein,leading to the third type of PFIC.Newer variations of this disease have been described.Loss of function of the tight junction protein 2 protein results in PFIC 4,while mutations of the NR1H4 gene,which encodes farnesoid X receptor,an important transcription factor for bile formation,cause PFIC 5.A recently described type of PFIC is associated with a mutation in the MYO5B gene,important for the trafficking of BSEP and hepatocyte membrane polarization.In this review,we provide a brief overview of the molecular mechanisms and clinical features associated with each type of PFIC based on peer reviewed journals published between 1993 and 2020.
文摘Familial intrahepatic cholestasis(FIC) comprises a group of rare cholestatic liver diseases associated with canalicular transport defects resulting predominantly from mutations in ATP8B1, ABCB11 and ABCB4. Phe-notypes range from benign recurrent intrahepatic cholestasis(BRIC), associated with recurrent cholestatic attacks, to progressive FIC(PFIC). Patients often suffer from severe pruritus and eventually progressive cholestasis results in liver failure. Currently, first-line treatment includes ursodeoxycholic acid in patients with ABCB4 deficiency(PFIC3) and partial biliary diversion in patients with ATP8B1 or ABCB11 deficiency(PFIC1 and PFIC2). When treatment fails, liver transplantation is needed which is associated with complications like rejection, post-transplant hepatic steatosis and recurrence of disease. Therefore, the need for more and better therapies for this group of chronic diseases remains. Here, we discuss new symptomatic treatment options like total biliary diversion, pharmacological diversion of bile acids and hepatocyte transplantation. Furthermore, we focus on emerging mutation-targeted therapeutic strategies, providing an outlook for future personalized treatment for inherited cholestatic liver diseases.
文摘Benign recurrent intrahepatic cholestasis （BRIC） is a Prare autosomal recessive liver disease characterizedby intermittent attacks of cholestasis that was first reported by Summerskill and Walshe in 1959.1 A few reports on patients with BRIC in China have been described in recent years, however, it is still a challenge to give the patients a correct diagnosis. Therefore, we collected five cases in the Beijing Friendship Hospital and the China-Japan Friendship Hospital in the past two years to summarize their clinical features, and explore the mutation region of the ATP8B1 gene from Chinese patients with BRIC.
