Publications by authors named "Véronique Barbu"

53 Publications

Characterization of a novel ABCC2 mutation in infantile Dubin Johnson syndrome.

Clin Chim Acta 2021 Mar 10;518:43-50. Epub 2021 Mar 10.

Laboratory of Molecular and Functional Genetics, Faculty of Science, University of Sfax, Tunisia. Electronic address:

Background And Aims: The Dubin Johnson Syndrome (DJS) occurs mostly in young adults but an early-onset of the disease has been reported in less common forms (Neonatal DJS and Infantile DJS). In this case, the clinical findings are of limit for the DJS diagnosis. Hence, the genetic testing remains the method of choice to provide an accurate diagnosis. In our study, we aimed to perform a genetic analysis for two siblings presented with an intrahepatic cholestasis before the age of 1 year to provide a molecular explanation for the developed phenotype.

Patients & Methods: A Tunisian family, having two siblings, manifesting signs of a hepatopathy, was enrolled in our study. A molecular analysis was performed, using a panel-based next generation sequencing, supplying results that were the subject of computational analysis. Then, a clinical follow-up was carried out to assess the evolution of the disease.

Results: The genetic analysis revealed the presence of a novel missense c.4179G > T, (p.M1393I) mutation in ABCC2 gene associated with a substitution c.2789G > A (R930Q) in ATP8B1 gene. Predictive results consolidated the pathogenic effect of both variants. These results confirmed the DJS diagnosis in the studied patients. The clinical course of both patients fit well with the benign nature of DJS.

Conclusion: We described here a novel ABCC2 mutation associated with a putative ATP8B1 modifier variant. This finding constituted the first report of a complex genotype in DJS. Hence, genetic analysis by a panel-based next generation sequencing permits an accurate diagnosis and the identification of putative variants that could influence the developed phenotype.
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http://dx.doi.org/10.1016/j.cca.2021.03.006DOI Listing
March 2021

Low-phospholipid-associated cholelithiasis syndrome: Prevalence, clinical features, and comorbidities.

JHEP Rep 2021 Apr 6;3(2):100201. Epub 2020 Nov 6.

Reference Center for Inflammatory Biliary Diseases and Autoimmune Hepatitis, ERN RARE-LIVER, Saint-Antoine Hospital, Assistance Publique-Hôpitaux de Paris, Sorbonne University, Paris, France.

Background & Aims: Low-phospholipid-associated cholelithiasis (LPAC) syndrome, a rare genetic form of intrahepatic cholelithiasis in adults, is still poorly understood. We report the results of the largest-ever case-control study of patients with LPAC syndrome aiming to assess the prevalence, clinical features, and comorbidities of the disease.

Methods: We included all LPAC cases diagnosed between 2001 and 2016 in 11 French centres. Controls consisted of all patients who underwent a cholecystectomy for common gallstone disease in a single non-academic centre over 1 year. A logistic regression analysis was used to identify the clinical features associated with LPAC syndrome across several patient strata with increasing levels of diagnostic confidence. The ratio between the incident cases of LPAC syndrome and the total number of cholecystectomies for gallstones was used to assess the relative prevalence of the disease.

Results: In this study, 308 cases and 206 controls were included. LPAC syndrome accounted for 0.5-1.9% of all patients admitted with symptomatic gallstone disease. Age at first symptoms <40 years, absence of overweight, persistence of symptoms after cholecystectomy, intrahepatic micro- or macrolithiasis, common bile duct (CBD) lithiasis, and no history of cholecystitis were independently associated with LPAC diagnosis. ATP-binding cassette subfamily B member 4 () variants, present in 46% of cases, were associated with CBD lithiasis, chronic elevation of gamma-glutamyltransferase (GGT), and personal or family history of hepato-biliary cancer.

Conclusions: In this case-control study, LPAC syndrome accounted for approximately 1% of symptomatic cholelithiasis in adults. In addition to pre-established diagnostic criteria, normal weight, CBD lithiasis, and no history of cholecystitis were significantly associated with the syndrome. gene variations in patients with LPAC were associated with CBD lithiasis, chronic cholestasis, and a personal or family history of hepato-biliary cancer.

Lay Summary: In the largest case-control study ever conducted in patients with LPAC syndrome, a rare genetic form of intrahepatic cholelithiasis in young adults, LPAC syndrome was found in approximately 1% of all patients admitted to the hospital for symptomatic gallstones and, in addition to the pre-established characteristics of the syndrome (age at first symptoms <40 years, recurrence of symptoms after cholecystectomy, and/or imaging evidence of intrahepatic microlithiasis), was associated with lower BMI, higher prevalence of common bile duct stones, and lower incidence of acute cholecystitis. gene variants, which were detected in about half of cases, were associated with common bile duct stones and a personal or family history of hepato-biliary cancer.
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http://dx.doi.org/10.1016/j.jhepr.2020.100201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7848766PMC
April 2021

Primary hyperparathyroidism as first manifestation in multiple endocrine neoplasia type 2A: an international multicenter study.

Endocr Connect 2020 Jun;9(6):489-497

Department of ORL Head & Neck Surgery and Audiology, Odense University Hospital, Odense, Denmark.

Objective: Multiple endocrine neoplasia type 2A (MEN 2A) is a rare syndrome caused by RET germline mutations and has been associated with primary hyperparathyroidism (PHPT) in up to 30% of cases. Recommendations on RET screening in patients with apparently sporadic PHPT are unclear. We aimed to estimate the prevalence of cases presenting with PHPT as first manifestation among MEN 2A index cases and to characterize the former cases.

Design And Methods: An international retrospective multicenter study of 1085 MEN 2A index cases. Experts from MEN 2 centers all over the world were invited to participate. A total of 19 centers in 17 different countries provided registry data of index cases followed from 1974 to 2017.

Results: Ten cases presented with PHPT as their first manifestation of MEN 2A, yielding a prevalence of 0.9% (95% CI: 0.4-1.6). 9/10 cases were diagnosed with medullary thyroid carcinoma (MTC) in relation to parathyroid surgery and 1/10 was diagnosed 15 years after parathyroid surgery. 7/9 cases with full TNM data were node-positive at MTC diagnosis.

Conclusions: Our data suggest that the prevalence of MEN 2A index cases that present with PHPT as their first manifestation is very low. The majority of index cases presenting with PHPT as first manifestation have synchronous MTC and are often node-positive. Thus, our observations suggest that not performing RET mutation analysis in patients with apparently sporadic PHPT would result in an extremely low false-negative rate, if no other MEN 2A component, specifically MTC, are found during work-up or resection of PHPT.
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http://dx.doi.org/10.1530/EC-20-0163DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354718PMC
June 2020

Genetic contribution of ABCC2 to Dubin-Johnson syndrome and inherited cholestatic disorders.

Liver Int 2020 01 13;40(1):163-174. Epub 2019 Oct 13.

INSERM, Centre de Recherche Saint-Antoine (CRSA), Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN), Sorbonne Université, Paris, France.

Background And Aims: The ABCC2 gene is implicated in Dubin-Johnson syndrome (DJS), a rare autosomal recessive liver disorder. The primary aim of this study was to determine the diagnostic value of ABCC2 genetic testing in the largest cohort of DJS reported to date. The high number of patients with cholestatic manifestations in this series prompted us to evaluate the genetic contribution of rare, potentially pathogenic ABCC2 variants to other inherited cholestatic disorders.

Methods: The cohort study included 32 patients with clinical DJS diagnosis, and 372 patients referred for the following disorders: low phospholipid-associated cholelithiasis (LPAC) syndrome, intrahepatic cholestasis of pregnancy (ICP) and benign recurrent intrahepatic cholestasis (BRIC). ABCC2 was screened by next-generation sequencing.

Results: Most patients with clinical DJS had positive genetic diagnosis (n = 30; 94%), with a great diversity of point mutations and copy number variations in ABCC2. Strikingly, eight (27%) of these patients showed transient cholestatic features at presentation: four neonatal cholestasis, two ICP, one contraceptive-induced cholestasis and one sporadic cholestasis. Conversely, the frequency of rare, heterozygous, potentially pathogenic ABCC2 variants in patients with LPAC, ICP or BRIC did not differ significantly from that of the general population.

Conclusions: This large series reveals that DJS is a highly homogeneous Mendelian disorder involving a large spectrum of ABCC2 variants. Genetic testing is crucial to establish early DJS diagnosis in patients with atypical presentations, such as neonatal cholestasis. This study also provides no evidence for the contribution of rare, potentially pathogenic ABCC2 variants to other inherited cholestatic disorders.
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http://dx.doi.org/10.1111/liv.14260DOI Listing
January 2020

Clinical characteristics and genetic profiles of young and adult patients with cholestatic liver disease.

Rev Esp Enferm Dig 2019 Oct;111(10):775-788

Genetics Service, Laboratoire commun de Biologie et Génétique Moléculaires, Hôpitaux universitaires Est Parisien, hôpi, France.

Background And Aims: heterozygous ABCB4, ABCB11 and ATP8B1 sequence variants were previously reported to be associated with low phospholipid-associated cholelithiasis, intrahepatic cholestasis of pregnancy, benign recurrent intrahepatic cholestasis and biliary lithiasis. The present study aimed to identify the presence of sequence variations in genes responsible for Mendelian liver disorders in patients with cholestatic liver disease.

Methods: targeted massive parallel sequencing of a panel of genes involved in bile acid homeostasis was performed in 105 young and adult patients with cholestatic liver disease in our laboratory for molecular diagnosis. The effects of novel variants were evaluated using bioinformatics prediction tools and the Protter and Phyre2 software programs were used to create 2D, 3D topology protein modeling. Genotype-phenotype correlation was established according to molecular analysis and clinical records.

Results: twenty novel heterozygous ABCB4 sequence variations, one heterozygous ABCB4 large intragenic deletion and only one novel missense variant in ABCB11 and ATP8B1 were identified. Interestingly, heterozygous and homozygous SLC4A2 missense variants were detected in patients with low phospholipid-associated cholelithiasis. Two patients harbored heterozygous GPBAR1 variants. Common variants such as homozygous ABCB11 p.Val444Ala and heterozygous ABCG8 p.Asp19His were also identified in 12 cases.

Conclusions: forty-eight variants were identified in five genes including ABCB4, ABCB11, ATP8B1, SLC4A2 and GPBAR1, twenty-five of which were novel. This study expands the phenotypic and mutational spectrum in genes involved in bile acid homeostasis and highlights the genetic and phenotypic heterogeneity in patients with inherited liver disorders.
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http://dx.doi.org/10.17235/reed.2019.6168/2019DOI Listing
October 2019

Intrahepatic Cholestasis Owing to a Novel Heterozygous ABCG8 Mutation and SLC4A2 Polymorphism With Favorable Outcome Under Ursodeoxycholic Acid.

Am J Gastroenterol 2019 09;114(9):1556-1559

Service d'hépato-gastroentérologie et nutrition, Hôpital Antoine-Béclère, Hôpitaux Universitaires Paris-Sud, Assistance Publique-Hôpitaux de Paris, Clamart, France.

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http://dx.doi.org/10.14309/ajg.0000000000000328DOI Listing
September 2019

A homozygous ABCB4 mutation causing an LPAC syndrome evolves into cholangiocarcinoma.

Clin Chim Acta 2019 Aug 7;495:598-605. Epub 2019 Jun 7.

Laboratory of Molecular and Functional Genetics, Faculty of Science, University of Sfax, Tunisia.

Low phospholipid-associated cholelithiasis (LPAC) is characterized by the association of ABCB4 mutations and low biliary phospholipid concentration with symptomatic and recurring cholelithiasis. In the present study, we reported a case of a 63-year-old woman, who presented a biliary pain beginning at the age of 30, recurrent after cholecystectomy, along with "comet-tail shadows" revealed by ultrasonography thus, fulfilling the diagnosis of LPAC. This disease evolved into a cholangiocarcinoma. To understand the molecular basis of this phenotype, we performed the ABCB4 gene sequencing, followed by in silico analysis and Q-RT-PCR assay. The results displayed a homozygous missense sequence variation (c.140G > A, p.Arg47Gln), predicted as pathogenic according to MutPred. Accordingly, this gave rise to a decreased hepatic ABCB4 mRNA level and structural alterations of the mutated protein. Eventually, we reported, here, the first description of an ABCB4 missense mutation (p.Arg47Gln) at homozygous state in a Tunisian LPAC syndrome. An elucidation of its functional consequences was performed. Besides, this case suggests that the delayed diagnosis of LPAC syndrome and the lack of UDCA treatment may contribute in the development of complications, such as cholangiocarcinoma.
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http://dx.doi.org/10.1016/j.cca.2019.06.007DOI Listing
August 2019

Editorial: Genetics of cholangiopathies.

Curr Opin Gastroenterol 2019 03;35(2):63-64

Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine (CRSA), Assistance Publique-Hôpitaux de Paris, Reference Center for Inflammatory Biliary Diseases and Autoimmune Hepatitis (CRMR, MIVB-H), Paris, France.

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http://dx.doi.org/10.1097/MOG.0000000000000510DOI Listing
March 2019

Expanding the mutational spectrum of the ABCB4 gene in inherited adult cholestatic liver disorders with four novel pathogenic variants.

Rev Esp Enferm Dig 2019 Jan;111(1):76-79

Genetics service, Laboratoire commun de Biologie et Génétique Moléculaires, Hôpitaux universitaires Est Parisien, hôpi, France.

Low phospholipid-associated cholelithiasis and intrahepatic cholestasis of pregnancy are two MDR3-related inherited liver disorders caused by biallelic or monoallelic ABCB4 loss-of-function variants. Low phospholipid-associated cholelithiasis is clinically characterized by the early onset of symptomatic cholelithiasis in young adults while intrahepatic cholestasis of pregnancy is a distinct clinical entity associated with adverse fetal outcomes. Of note, patients carrying ABCB4 sequence variations commonly exhibit phenotypic expression over a wide continuum due to environmental and hormonal contributing factors and genetic modifiers. Patients with an early diagnosis of MDR3-related diseases could benefit from ursodeoxycholic acid treatment in order to prevent acute and chronic complications as well as adverse pregnancy outcomes. We herein report five patients with an overlapping phenotype from low phospholipid-associated cholelithiasis to intrahepatic cholestasis of pregnancy, harboring five ABCB4 missense variants, four of which were novel. Our study highlights the phenotypic and genetic heterogeneity of inherited cholestatic liver diseases and also expands the mutation spectrum of ABCB4 sequence variations in adult cholestatic liver diseases.
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http://dx.doi.org/10.17235/reed.2018.5828/2018DOI Listing
January 2019

Phenotypic variability in Tunisian PFIC3 patients harboring a complex genotype with a differential clinical outcome of UDCA treatment.

Clin Chim Acta 2018 Nov 20;486:122-128. Epub 2018 Jul 20.

Laboratory of Molecular and Functional Genetics, University of Sfax, Tunisia. Electronic address:

Introduction: Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a chronic autosomal recessive disorder characterized by a wide spectrum of clinical severity generally related to the degree of pathogenicity of the causal sequence variation in ABCB4 gene.

Patients And Methods: The present study reports the molecular investigation by Next Generation Sequencing (NGS) of five related patients with PFIC3 disease followed by bioinformatic analysis. A biochemical follow-up is also performed to assess the response of the ursodeoxycholic acid treatment.

Results: The molecular results revealed complex genotype in homozygous state in all patients including a pathogenic c.1436C > T (P479L) variation in the ABCB4 gene and two well-known polymorphisms, the V444A in ABCB11 gene and the D19H in the ABCG8 gene. Although the presence of the same genetic background, all patients present the disease at different ages and clinical signs with a variable degree of clinical severity at diagnosis. Additionally, a differential outcome to the treatment has been pointed out.

Conclusion: Our results provide evidence regarding the putative intervention of modifier factors in the phenotypic variability reported for the first time in the PFIC3 disease and highlight the importance of an early administration of the UDCA as a good solution to ovoid the disease progression.
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http://dx.doi.org/10.1016/j.cca.2018.07.035DOI Listing
November 2018

Correction to: Dubin-Johnson syndrome and intrahepatic cholestasis of pregnancy in a Sri Lankan family: a case report.

BMC Res Notes 2017 10 5;10(1):492. Epub 2017 Oct 5.

Laboratoire Commun de Biologie et de Génétique Moléculaires, Hôpital Saint-Antoine, 184, rue du Faubourg Saint-Antoine, 75012, Paris, France.

Following publication of the original article [1], the authors requested the following corrections: 1. Author 2-given name should be Dilanthi and family name Warawitage. 2. Author 6-given name should be Nalika and family name de Silva.
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http://dx.doi.org/10.1186/s13104-017-2815-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5629802PMC
October 2017

Nationwide French Study of RET Variants Detected from 2003 to 2013 Suggests a Possible Influence of Polymorphisms as Modifiers.

Thyroid 2017 12 3;27(12):1511-1522. Epub 2017 Nov 3.

3 Réseau TenGen , France .

Background: The presence of single nucleotide polymorphisms (SNPs) in the REarranged during Transfection (RET) gene has been investigated with regard to their potential role in the development or progression of medullary thyroid cancer or pheochromocytomas (PHEO) in patients with the multiple endocrine neoplasia type 2 (MEN2) syndrome. The aim of this study was to evaluate the spectrum of RET variants in France between 2003 and 2013, and to evaluate the impact of SNPs on the MEN2 A phenotype.

Methods: In this retrospective cohort study, RET variants were screened in 5109 index cases, and RET pathogenic variants were screened in 2214 relatives. Exons 5, 8, 10, 11, 13, 14, 15, and 16 were characterized by Sanger sequencing. RET pathogenic variants, RET variants with unknown functional significance (VUS), and four RET SNP variants-G691S (rs1799939), L769L (rs1800861), S836S (rs1800862), and S904S (rs1800863)-were characterized and are reported in index cases. In silico analysis and classification following the recommendation of the American College of Medical Genetics and Genomics was performed for RET VUS. Each patient's age at the time of diagnosis, sex, and the endocrine neoplasias present at molecular diagnosis were recorded.

Results: Twenty-six single VUS in RET without any well-defined risk profiles were found in 33 patients. Nine of these were considered probably pathogenic, 11 of uncertain significance, and six as probably benign. Three double pathogenic variants found in three patients were classified as pathogenic. A study of the entire cohort showed that patients carrying pathogenic variants or VUS in RET together with PHEO were diagnosed earlier than the others. The presence of the G691S SNP, or a combination of SNPs, increased the risk of developing PHEO but did not modify the date of the diagnosis. No association was found between SNPs and medullary thyroid cancer or hyperparathyroidism.

Conclusions: The findings propose a classification of 15 of the 26 VUS in RET without any well-defined risk profiles and suggest that the G691S SNP, or a combination of SNPs, may be associated with the development of PHEO.
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http://dx.doi.org/10.1089/thy.2016.0399DOI Listing
December 2017

Dubin-Johnson syndrome and intrahepatic cholestasis of pregnancy in a Sri Lankan family: a case report.

BMC Res Notes 2017 Sep 18;10(1):487. Epub 2017 Sep 18.

Laboratoire Commun de Biologie et de Génétique Moléculaires, Hôpital Saint-Antoine, 184, rue du Faubourg Saint-Antoine, 75012, Paris, France.

Background: Dubin-Johnson syndrome and intrahepatic cholestasis of pregnancy are rare chronic liver disorders. Dubin-Johnson syndrome may manifest as conjugated hyperbilirubinemia, darkly pigmented liver, presence of abnormal pigment in the parenchyma of hepatocytes and abnormal distribution of the coproporphyrin isomers I and III in the urine. Intrahepatic cholestatic jaundice of pregnancy presents as pruritus, abnormal liver biochemistry and increased serum bile acids.

Case Presentation: A Sri Lankan girl presented with recurrent episodes of jaundice. She had conjugated hyperbilirubinaemia with diffuse, coarse brown pigments in the hepatocytes. Urine coproporphyrin examination suggested Dubin-Johnson syndrome. Genetic studies confirmed missense homozygous variant p.Trp709Arg in the ATP-binding cassette sub-family C member 2 gene ABCC2 that encodes the Multidrug resistance-associated protein 2 that causes Dubin-Johnson syndrome. The gene study of the mother revealed the same missense variant in ABCC2/MRP2 but with a heterozygous status, and in addition a homozygous missense variant p.Val444Ala in the ATP-binding cassette, sub-family B member 11 gene ABCB11 that encodes the bile salt export pump.

Conclusion: Dubin-Johnson syndrome should be considered when the common causes for conjugated hyperbilirubinaemia have been excluded, and patient has an increased percentage of direct bilirubin relative to total bilirubin concentration. Its early diagnosis prevents repeated hospital admissions and investigations. Knowledge of a well known homozygous variant in ABCB11 gene could help in the management of pregnancy.
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http://dx.doi.org/10.1186/s13104-017-2811-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5604299PMC
September 2017

Comparison of in silico prediction and experimental assessment of ABCB4 variants identified in patients with biliary diseases.

Int J Biochem Cell Biol 2017 08 3;89:101-109. Epub 2017 Jun 3.

Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, F-75012, Paris, France.

Genetic variations of the phosphatidylcholine transporter, ABCB4 cause several biliary diseases. The large number of reported variations makes it difficult to foresee a comprehensive study of each variation. To appreciate the reliability of in silico prediction programs, 1) we confronted them with the assessment in cell models of two ABCB4 variations (E528D and P1161S) identified in patients with low phospholipid-associated cholelithiasis (LPAC); 2) we extended the confrontation to 19 variations that we had previously characterized in cellulo. Four programs (Provean, Polyphen-2, PhD-SNP and MutPred) were used to predict the degree of pathogenicity. The E528D and P1161S variants were studied in transfected HEK293 and HepG2 cells by immunofluorescence, immunoblotting and measurement of phosphatidylcholine secretion. All prediction tools qualified the P1161S variation as deleterious, but provided conflicting results for E528D. In cell models, both mutants were expressed and localized as the wild type but their activity was significantly reduced, by 48% (P1161S) and 33% (E528D). These functional defects best correlated with MutPred predictions. MutPred program also proved the most accurate to predict the pathogenicity of the 19 ABCB4 variants that we previously characterized in cell models, and the most sensitive to predict the pathogenicity of 65 additional mutations of the Human Gene Mutation Database. These results confirm the pathogenicity of E528D and P1161S variations and suggest that even a moderate decrease (by less than 50%) of phosphatidylcholine secretion can cause LPAC syndrome. They highlight the reliability of in silico prediction tools, most notably MutPred, as a first approach to predict the pathogenicity of ABCB4 variants.
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http://dx.doi.org/10.1016/j.biocel.2017.05.028DOI Listing
August 2017

Functional defect of variants in the adenosine triphosphate-binding sites of ABCB4 and their rescue by the cystic fibrosis transmembrane conductance regulator potentiator, ivacaftor (VX-770).

Hepatology 2017 02 24;65(2):560-570. Epub 2016 Dec 24.

Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMR_S 938, Saint-Antoine Research Center, F-75012, Paris, France.

ABCB4 (MDR3) is an adenosine triphosphate (ATP)-binding cassette (ABC) transporter expressed at the canalicular membrane of hepatocytes, where it mediates phosphatidylcholine (PC) secretion. Variations in the ABCB4 gene are responsible for several biliary diseases, including progressive familial intrahepatic cholestasis type 3 (PFIC3), a rare disease that can be lethal in the absence of liver transplantation. In this study, we investigated the effect and potential rescue of ABCB4 missense variations that reside in the highly conserved motifs of ABC transporters, involved in ATP binding. Five disease-causing variations in these motifs have been identified in ABCB4 (G535D, G536R, S1076C, S1176L, and G1178S), three of which are homologous to the gating mutations of cystic fibrosis transmembrane conductance regulator (CFTR or ABCC7; i.e., G551D, S1251N, and G1349D), that were previously shown to be function defective and corrected by ivacaftor (VX-770; Kalydeco), a clinically approved CFTR potentiator. Three-dimensional structural modeling predicted that all five ABCB4 variants would disrupt critical interactions in the binding of ATP and thereby impair ATP-induced nucleotide-binding domain dimerization and ABCB4 function. This prediction was confirmed by expression in cell models, which showed that the ABCB4 mutants were normally processed and targeted to the plasma membrane, whereas their PC secretion activity was dramatically decreased. As also hypothesized on the basis of molecular modeling, PC secretion activity of the mutants was rescued by the CFTR potentiator, ivacaftor (VX-770).

Conclusion: Disease-causing variations in the ATP-binding sites of ABCB4 cause defects in PC secretion, which can be rescued by ivacaftor. These results provide the first experimental evidence that ivacaftor is a potential therapy for selected patients who harbor mutations in the ATP-binding sites of ABCB4. (Hepatology 2017;65:560-570).
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http://dx.doi.org/10.1002/hep.28929DOI Listing
February 2017

LPAC syndrome associated with deletion of the full exon 4 in a ABCB4 genetic mutation in a patient with hepatitis C.

Rev Esp Enferm Dig 2014 Dec;106(8):544-7

Low-phospholipid-associated cholelithiasis syndrome (LPAC) is associated with ABCB4 genetic mutation. ABCB4 encodes MDR3 protein, involved in biliary phosphatidylcholine excretion.Higher prevalence in women, biliary symptoms in young adults and ursodesoxycholic acid (UDCA) response are the main features. We report the case of a 48-year-old man with hepatitis C, genotype 1b, fibrosis F3, null responder to Peg-IFN-alpha-2b/ribavirin and nephritic colic. In 2011 he developed jaundice, pruritus and epigastric pain.He showed increased serum levels of AST, ALT, GGT, bilirubin and alpha-fetoprotein, and viral load (14,600,000 IU/mL). Pancreatic- CT, endoscopic ultrasonography and echo-Doppler showed noncirrhotic chronic liver disease. The episode resolved spontaneously and one year later he suffered a similar episode. UDCA was started with excellent response. An immunohistochemistry study and sequencing of ABCB4 did not find alteration. MLPA® technique detected heterozygous deletion of the full exon 4 confirming LPAC syndrome diagnosis.
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December 2014

Portal myofibroblasts promote vascular remodeling underlying cirrhosis formation through the release of microparticles.

Hepatology 2015 Mar 22;61(3):1041-55. Epub 2015 Jan 22.

Sorbonne Universités, UPMC Université Paris 06, CDR Saint-Antoine and Institute of Cardiometabolism and Nutrition (ICAN), Paris, France; INSERM, UMR_S 938, Paris, France.

Unlabelled: Liver fibrosis expanding from portal tracts and vascular remodeling are determinant factors in the progression of liver diseases to cirrhosis. In the present study, we examined the potential contribution of portal myofibroblasts (PMFs) to the vascular changes leading to cirrhosis. The analyses of liver cells based on the transcriptome of rat PMFs, compared to hepatic stellate cell HSC-derived myofibroblasts in culture, identified collagen, type XV, alpha 1 (COL15A1) as a marker of PMFs. Normal liver contained rare COL15A1-immunoreactive cells adjacent to the bile ducts and canals of Hering in the portal area. A marked increase in COL15A1 expression occurred together with that of the endothelial marker, von Willebrand factor, in human and rat liver tissue, at advanced stages of fibrosis caused by either biliary or hepatocellular injury. In cirrhotic liver, COL15A1-expressing PMFs adopted a perivascular distribution outlining vascular capillaries proximal to reactive ductules, within large fibrotic septa. The effect of PMFs on endothelial cells (ECs) was evaluated by in vitro and in vivo angiogenesis assays. PMF-conditioned medium increased the migration and tubulogenesis of liver ECs as well as human umbilical vein ECs and triggered angiogenesis within Matrigel plugs in mice. In coculture, PMFs developed intercellular junctions with ECs and enhanced the formation of vascular structures. PMFs released vascular endothelial growth factor (VEGF)A-containing microparticles, which activated VEGF receptor 2 in ECs and largely mediated their proangiogenic effect. Cholangiocytes potentiated the angiogenic properties of PMFs by increasing VEGFA expression and microparticle shedding in these cells.

Conclusion: PMFs are key cells in hepatic vascular remodeling. They signal to ECs through VEGFA-laden microparticles and act as mural cells for newly formed vessels, driving scar progression from portal tracts into the parenchyma.
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http://dx.doi.org/10.1002/hep.27318DOI Listing
March 2015

Phosphorylation of ABCB4 impacts its function: insights from disease-causing mutations.

Hepatology 2014 Aug 19;60(2):610-21. Epub 2014 May 19.

INSERM, UMR_S 938, CDR Saint-Antoine, F-75012, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UMR_S 938 and Institute of Cardiometabolism and Nutrition (ICAN), F-75005, Paris, France.

Unlabelled: The ABCB4 transporter mediates phosphatidylcholine (PC) secretion at the canalicular membrane of hepatocytes and its genetic defects cause biliary diseases. Whereas ABCB4 shares high sequence identity with the multidrug transporter, ABCB1, its N-terminal domain is poorly conserved, leading us to hypothesize a functional specificity of this domain. A database of ABCB4 genotyping in a large series of patients was screened for variations altering residues of the N-terminal domain. Identified variants were then expressed in cell models to investigate their biological consequences. Two missense variations, T34M and R47G, were identified in patients with low-phospholipid-associated cholelithiasis or intrahepatic cholestasis of pregnancy. The T34M and R47G mutated proteins showed no or minor defect, respectively, in maturation and targeting to the apical membrane, in polarized Madin-Darby Canine Kidney and HepG2 cells, whereas their stability was similar to that of wild-type (WT) ABCB4. By contrast, the PC secretion activity of both mutants was markedly decreased. In silico analysis indicated that the identified variants were likely to affect ABCB4 phosphorylation. Mass spectrometry analyses confirmed that the N-terminal domain of WT ABCB4 could undergo phosphorylation in vitro and revealed that the T34M and R47G mutations impaired such phosphorylation. ABCB4-mediated PC secretion was also increased by pharmacological activation of protein kinases A or C and decreased by inhibition of these kinases. Furthermore, secretion activity of the T34M and R47G mutants was less responsive than that of WT ABCB4 to protein kinase modulators.

Conclusion: We identified disease-associated variants of ABCB4 involved in the phosphorylation of its N-terminal domain and leading to decreased PC secretion. Our results also indicate that ABCB4 activity is regulated by phosphorylation, in particular, of N-terminal residues.
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http://dx.doi.org/10.1002/hep.27170DOI Listing
August 2014

Prevalence of low phospholipid-associated cholelithiasis in young female patients.

Dig Liver Dis 2013 Nov 16;45(11):915-9. Epub 2013 May 16.

Services d'hépato-gastro-entérologie, de radiologie et de chirurgie viscérale, Hôpital Saint-Camille, Bry-sur-Marne, France. Electronic address:

Background And Aims: We evaluated the prevalence of low phospholipid-associated cholelithiasis, a specific form of cholelithiasis associated with at least 2 of the 3 following criteria: first symptoms before the age of 40; intrahepatic comet tail artefacts, sludge or microlithiasis on ultrasound imaging; and recurrence of symptoms after cholecystectomy.

Methods: We prospectively studied the cases of 60 consecutive female patients under 30 with symptomatic cholelithiasis.

Results: A diagnosis of low phospholipid-associated cholelithiasis was made in 14/60 patients (23%). The molecular analysis showed ABCB4 (n=4) and ABCB11 (n=4) gene mutations. Low phospholipid-associated cholelithiasis was frequently observed in non-overweight patients [13/27 (48%)], was present in most patients whose biliary symptoms occurred before the age of 18 [7/10 (70%)] and was often associated with cholangitis or acute pancreatitis [9/14 (64%), p<0.05] while "common" cholelithiasis was mainly associated with cholecystitis [16/46 (35%), p<0.05].

Conclusion: Nearly one quarter of the female patients under the age of 30 admitted for symptomatic cholelithiasis had low phospholipid-associated cholelithiasis; particularly if body weight was normal, the symptoms began before the age of 18 or in the presence of severe biliary complications.
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http://dx.doi.org/10.1016/j.dld.2013.04.002DOI Listing
November 2013

Genotype-phenotype relationships in the low-phospholipid-associated cholelithiasis syndrome: a study of 156 consecutive patients.

Hepatology 2013 Sep 29;58(3):1105-10. Epub 2013 Jul 29.

UPMC Univ Paris 06, INSERM, UMR_S 938, Paris, France; INSERM, U938, Centre de Recherche Saint-Antoine, Paris, France.

Unlabelled: The low-phospholipid-associated cholelithiasis syndrome (LPAC; OMIM 171060) is a peculiar form of intrahepatic cholelithiasis occurring in young adults, associated with ABCB4/MDR3 gene sequence variations. Our aim was to determine the genotype-phenotype relationships in 156 consecutive patients with the criteria of LPAC syndrome. A variant was detected in 79 (61 missense and 18 truncating sequence variants), 63 being monoallelic. The clinical features (age at onset, high prevalence in women, frequency and severity of acute and chronic complications, intrahepatic cholestasis of pregnancy [ICP]) were similar in the patients with or without ABCB4 gene sequence variation. Truncating variations were associated with an earlier onset of symptoms both in women and men. Acute and chronic biliary complications were variant-independent. Half of the women who had pregnancy developed ICP. The frequency of ICP and fetal complications were similar in patients with missense and truncating variants.

Conclusion: The LPAC syndrome is more frequent in women and highly associated with ICP. Half of the patients harbored missense or truncating variants of the ABCB4 gene. The characteristics of the patients without detectable variant are similar to those with variant, indicating that yet unexplored regions of the ABCB4 and other genes may be involved.
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http://dx.doi.org/10.1002/hep.26424DOI Listing
September 2013

Novel mutations in the Dubin-Johnson syndrome gene ABCC2/MRP2 and associated biochemical changes.

Ann Clin Biochem 2012 Nov 12;49(Pt 6):609-12. Epub 2012 Oct 12.

Department of Biochemistry, Wishaw General Hospital, 50 Netherton Street, Wishaw, Lanarkshire ML2 0DP, UK.

A patient with sepsis and jaundice was admitted for diagnosis and treatment. Associated biochemical changes included increased C-reactive protein, conjugated bilirubin and gamma-glutamyltransferase, the duration of which was protracted. High urine coproporphyrin isomer-1 and immunostaining of liver tissue suggested Dubin-Johnson syndrome. DNA sequencing using polymerase chain reaction amplification of the ABCC2 gene revealed the patient to have a compound heterozygous variant of MRP2, a molecule involved in canalicular transport of bilirubin. There was a history of jaundice since infancy.
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http://dx.doi.org/10.1258/acb.2012.011279DOI Listing
November 2012

Connecting dysbiosis, bile-acid dysmetabolism and gut inflammation in inflammatory bowel diseases.

Gut 2013 Apr 19;62(4):531-9. Epub 2012 Sep 19.

INSERM ERL U 1057, UMR7203, Paris, France.

Objective: Gut microbiota metabolises bile acids (BA). As dysbiosis has been reported in inflammatory bowel diseases (IBD), we aim to investigate the impact of IBD-associated dysbiosis on BA metabolism and its influence on the epithelial cell inflammation response.

Design: Faecal and serum BA rates, expressed as a proportion of total BA, were assessed by high-performance liquid chromatography tandem mass spectrometry in colonic IBD patients (42) and healthy subjects (29). The faecal microbiota composition was assessed by quantitative real-time PCR. Using BA profiles and microbiota composition, cluster formation between groups was generated by ranking models. The faecal BA profiles in germ-free and conventional mice were compared. Direct enzymatic activities of BA biotransformation were measured in faeces. The impact of BA on the inflammatory response was investigated in vitro using Caco-2 cells stimulated by IL-1β.

Results: IBD-associated dysbiosis was characterised by a decrease in the ratio between Faecalibacterium prausntizii and Escherichia coli. Faecal-conjugated BA rates were significantly higher in active IBD, whereas, secondary BA rates were significantly lower. Interestingly, active IBD patients exhibited higher levels of faecal 3-OH-sulphated BA. The deconjugation, transformation and desulphation activities of the microbiota were impaired in IBD patients. In vitro, secondary BA exerted anti-inflammatory effects, but sulphation of secondary BAs abolished their anti-inflammatory properties.

Conclusions: Impaired microbiota enzymatic activity observed in IBD-associated dysbiosis leads to modifications in the luminal BA pool composition. Altered BA transformation in the gut lumen can erase the anti-inflammatory effects of some BA species on gut epithelial cells and could participate in the chronic inflammation loop of IBD.
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http://dx.doi.org/10.1136/gutjnl-2012-302578DOI Listing
April 2013

Epidermal growth factor receptor and HER-3 restrict cell response to sorafenib in hepatocellular carcinoma cells.

J Hepatol 2012 Jul 10;57(1):108-15. Epub 2012 Mar 10.

UPMC Univ Paris 06, UMR_S 938, F-75012 Paris, France.

Background & Aims: Sorafenib is the standard of care for the treatment of advanced hepatocellular carcinoma (HCC). However, primary and acquired resistance is observed in patients. We examined whether gefitinib, which inhibits both epidermal growth factor receptor (EGFR) and HER-3 phosphorylation, could improve HCC cell response to sorafenib.

Methods: Sorafenib and gefitinib were tested in HCC tumor xenografts and in sorafenib-sensitive and sorafenib-resistant HCC cell lines. Biomarkers relevant to the HER system were analyzed by Western blotting and ELISA. RNA interference was used to downregulate the HER system. Amphiregulin concentrations were measured by ELISA in sera from patients under sorafenib treatment.

Results: Sorafenib combined with gefitinib significantly inhibited tumor growth in mice and reduced cell viability in vitro compared to single agents. In cell lines cultured in 10% serum or treated with EGF, sorafenib alone inhibited phospho-STAT3 while it maintained or even increased phospho-ERK and/or phospho-AKT. The paradoxical effects of sorafenib were prevented by gefitinib or by downregulation of EGFR and HER-3 expression. In cells with acquired resistance to sorafenib, aberrant activation of EGFR/HER-3 receptors as well as overexpression of several EGFR ligands were observed. These enhanced autocrine/paracrine loops led to the constitutive activation of ERK and AKT and conferred increased sensitivity to gefitinib. Increased serum concentrations of amphiregulin were observed in 10 out of 14 patients under sorafenib treatment compared to baselines.

Conclusions: Signaling pathways controlled by EGFR and HER-3 restrict sorafenib effects both in naive and sorafenib-resistant HCC cells. Consequently, gefitinib cooperates with sorafenib to increase antiproliferative response and to prevent resistance.
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http://dx.doi.org/10.1016/j.jhep.2012.02.019DOI Listing
July 2012

Defects in gallbladder emptying and bile Acid homeostasis in mice with cystic fibrosis transmembrane conductance regulator deficiencies.

Gastroenterology 2012 Jun 24;142(7):1581-91.e6. Epub 2012 Feb 24.

UPMC Univ Paris 06 and INSERM, UMR_S 938, CdR Saint-Antoine, Paris, France.

Background & Aims: Patients with cystic fibrosis (CF) have poorly defined defects in biliary function. We evaluated the effects of cystic fibrosis transmembrane conductance regulator (CFTR) deficiency on the enterohepatic disposition of bile acids (BAs).

Methods: Bile secretion and BA homeostasis were investigated in Cftr(tm1Unc) (Cftr-/-) and CftrΔF508 (ΔF508) mice.

Results: Cftr-/- and ΔF508 mice did not grow to normal size, but did not have liver abnormalities. The gallbladders of Cftr-/- mice were enlarged and had defects in emptying, based on (99m)technetium-mebrofenin scintigraphy or post-prandial variations in gallbladder volume; gallbladder contraction in response to cholecystokinin-8 was normal. Cftr-/- mice had abnormal gallbladder bile and duodenal acidity, and overexpressed the vasoactive intestinal peptide-a myorelaxant factor for the gallbladder. The BA pool was larger in Cftr-/- than wild-type mice, although there were no differences in fecal loss of BAs. Amounts of secondary BAs in portal blood, liver, and bile of Cftr-/- mice were much lower than normal. Expression of genes that are induced by BAs, including fibroblast growth factor-15 and BA transporters, was lower in the ileum but higher in the gallbladders of Cftr-/- mice, compared with wild-type mice, whereas enzymes that synthesize BA were down-regulated in livers of Cftr-/- mice. This indicates that BAs underwent a cholecystohepatic shunt, which was confirmed using cholyl-(Ne-NBD)-lysine as a tracer. In Cftr-/- mice, cholecystectomy reversed most changes in gene expression and partially restored circulating levels of secondary BAs. The ΔF508 mice overexpressed vasoactive intestinal peptide and had defects in gallbladder emptying and in levels of secondary BAs, but these features were less severe than in Cftr-/- mice.

Conclusions: Cftr-/- and CftrΔF508 mice have defects in gallbladder emptying that disrupt enterohepatic circulation of BAs. These defects create a shunt pathway that restricts the amount of toxic secondary BAs that enter the liver.
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http://dx.doi.org/10.1053/j.gastro.2012.02.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3579557PMC
June 2012

Aspects of liver pathology in adult patients with MDR3/ABCB4 gene mutations.

Virchows Arch 2012 Mar 14;460(3):291-8. Epub 2012 Feb 14.

Service d'Anatomie Pathologique, APHP, Hôpital St Antoine, 75012 Paris, France.

The aims of this study were to describe the histological liver lesions in adult patients with MDR3/ ABCB4 mutation and to study the usefulness of MDR3 immunostaining as a diagnostic tool. All adult patients from our institution with an MDR3/ABCB4 mutation and a liver histology were included (n = 13). Eleven patients had a single heterozygous gene mutation and two patients had two heterozygous mutations. Two patients had no liver lesions. Eight patients had a mild ductular reaction and portal fibrosis. One patient had a few fibrous septa and two patients had biliary cirrhosis. In three cases intraductal lipid crystals were identified. Two patients had biliary fibroobliterative lesions with no sclerosing cholangitis on cholangiography. Biliary dysplasia was identified in hepatectomy specimens from two patients, one of whom developed an intrahepatic cholangiocarcinoma. One patient with biliary cirrhosis developed a hepatocellular carcinoma. MDR3 immunostainings performed on formalin-fixed paraffin-embedded sections showed a strong canalicular staining in all patients except in one. To conclude, the predominant histological features were ductular reaction with no or mild fibrosis without cholangitis. Liver lesions previously unreported in association with MDR3/ABCB4 gene mutations (biliary dysplasia, cholangiocarcinoma, small duct sclerosing cholangitis) were also found. Lipid crystals in bile ducts may be suggestive of MDR3/ABCB4 mutation. MDR3 immunostaining on formalin-fixed paraffin-embedded sections does not seem to be sensitive for the diagnosis of heterozygous MDR3/ABCB4 mutations.
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http://dx.doi.org/10.1007/s00428-012-1202-6DOI Listing
March 2012

Cross-validation study for epidermal growth factor receptor and KRAS mutation detection in 74 blinded non-small cell lung carcinoma samples: a total of 5550 exons sequenced by 15 molecular French laboratories (evaluation of the EGFR mutation status for the administration of EGFR-TKIs in non-small cell lung carcinoma [ERMETIC] project--part 1).

J Thorac Oncol 2011 Jun;6(6):1006-15

Laboratoire de Biologie Moléculaire, Hôpital de Hautepierre, Strasbourg, France.

Introduction: The Evaluation of the epidermal growth factor receptor (EGFR) Mutation status for the administration of EGFR-Tyrosine Kinase Inhibitors in non-small cell lung Carcinoma (NSCLC) (ERMETIC) project part 1 assessed the accuracy of EGFR and KRAS mutations detection in NSCLC among 15 French centers.

Methods: The 15 ERMETIC centers selected 74 NSCLC surgical specimens from previously untreated patients. Paraffin and paired frozen DNA were sequenced for EGFR exons 18 to 21 and KRAS exon 2 by an external molecular laboratory, yielding a gold standard. The 74 blinded paraffin DNAs were redistributed to the 15 ERMETIC laboratories for sequencing of a total of 5550 exons. Results were compared with the gold standard and between centers by discordance rates and kappa statistics.

Results: The gold standard included 39 mutated samples with 22 EGFR and 17 KRAS mutated samples. Kappa statistics showed that 10, 6, and 6 of the 15 ERMETIC centers had a moderate to good kappa score, when compared with external laboratory for EGFR exon 19, EGFR exon 21, and KRAS exon 2, respectively. Kappa statistics showed moderate score between centers which increased to good for EGFR exon 19 mutation when removing 16 poor-quality samples with high nonamplificable rates.

Conclusions: Paraffin-embedded specimens may represent a suitable source of DNA for sequencing analyses in ERMETIC centers. EGFR exon 19 deletions were most accurately detected by ERMETIC centers. Ease and accuracy of results, depended more on the quality of sample than on the difference in molecular sequencing procedures between centers, emphasize the need of preanalytical quality control programs.
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http://dx.doi.org/10.1097/JTO.0b013e318211dceeDOI Listing
June 2011

Combined features of low phospholipid-associated cholelithiasis and progressive familial intrahepatic cholestasis 3.

Liver Int 2010 Feb 19;30(2):327-31. Epub 2009 Oct 19.

UPMC Université Paris, Paris, France.

Adenosine triphosphate-binding cassette, subfamily B, member 4 (ABCB4) gene alterations can cause two distinct clinical entities: progressive familial intrahepatic cholestasis type 3 (PFIC3) and low phospholipid-associated cholelithiasis (LPAC). Based on the findings in two siblings and a review of the literature, we aimed to identify determinants of disease phenotypic traits associated with ABCB4 gene alterations. Two siblings presented, before the age of 30 years, recurrent symptomatic cholelithiasis and extensive biliary fibrosis that progressed towards portal hypertension and liver failure necessitating liver transplantation. We analysed the sequence of the ABCB4 gene and immunolocalization of the protein in the liver. Sequence analysis of ABCB11, potentially involved in similar symptoms, was also performed. Two heterozygous non-synonymous variants of ABCB4 were found in both siblings. One of them (c.959C>T; p.Ser320Phe) was previously implicated in LPAC and the second one (c.2858C>A; p.Ala953Asp) in PFIC3. Both patients were also heterozygous for the ABCB11 variant Val444Ala, which predisposes to cholestatic disorders. ABCB4 was normally detected at the canalicular membrane of hepatocytes. The review of ABCB4 gene variants reported so far shows that the vast majority of variants causing PFIC3 and LPAC are distinct. Also as a general rule, homozygous variants cause PFIC3 while heterozygous variants lead to LPAC. Combined PFIC3 and LPAC phenotype is a rare clinical event, which may be determined by the coexistence of ABCB4 variants related to both phenotypes and also potentially to the ABCB11 variant. Thus, most of the patients presenting with LPAC are not at a particular risk of developing PFIC3 features in adulthood.
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http://dx.doi.org/10.1111/j.1478-3231.2009.02148.xDOI Listing
February 2010

Ezrin-radixin-moesin-binding phosphoprotein (EBP50), an estrogen-inducible scaffold protein, contributes to biliary epithelial cell proliferation.

Am J Pathol 2009 Mar;174(3):869-80

INSERM, UMR_S 893, CdR Saint-Antoine, Faculté de Médecine Pierre et Marie Curie, site Saint-Antoine, 27, rue Chaligny, 75571 Paris cedex 12, France.

Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) anchors and regulates apical membrane proteins in epithelia. EBP50 is inducible by estrogen and may affect cell proliferation, although this latter function remains unclear. The goal of this study was to determine whether EBP50 was implicated in the ductular reaction that occurs in liver disease. EBP50 expression was examined in normal human liver, in human cholangiopathies (ie, cystic fibrosis, primary biliary cirrhosis, and primary sclerosing cholangitis), and in rats subjected to bile-duct ligation. The regulation of EBP50 by estrogens and its impact on proliferation were assessed in both bile duct-ligated rats and Mz-Cha-1 human biliary epithelial cells. Analyses of cell isolates and immunohistochemical studies showed that in normal human liver, EBP50 is expressed in the canalicular membranes of hepatocytes and, together with ezrin and cystic fibrosis transmembrane conductance regulator, in the apical domains of cholangiocytes. In both human cholangiopathies and bile duct-ligated rats, EBP50 was redistributed to the cytoplasmic and nuclear compartments. EBP50 underwent a transient increase in rat cholangiocytes after bile-duct ligation, whereas such expression was down-regulated in ovariectomized rats. In addition, in Mz-Cha-1 cells, EBP50 underwent up-regulation and intracellular redistribution in response to 17beta-estradiol, whereas its proliferation was inhibited by siRNA-mediated EBP50 knockdown. These results indicate that both the expression and distribution of EBP50 are regulated by estrogens and contribute to the proliferative response in biliary epithelial cells.
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http://dx.doi.org/10.2353/ajpath.2009.080079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2665747PMC
March 2009

Genetic factors of susceptibility and of severity in primary biliary cirrhosis.

J Hepatol 2008 Dec 1;49(6):1038-45. Epub 2008 Oct 1.

UPMC University of Paris 06, UMRS_893, CdR Saint-Antoine, F-75012 Paris, France.

Background/aims: In primary biliary cirrhosis (PBC), pathogenesis is influenced by genetic factors that remain poorly elucidated up to now. We investigated the impact of sequence diversity in candidate genes involved in immunity (CTLA-4 and TNFalpha), in bile formation (10 hepatobiliary transporter genes) and in the adaptative response to cholestasis (three nuclear receptor genes) on the susceptibility and severity of PBC.

Methods: A total of 42 Ht SNPs were identified and compared in 258 PBC patients and two independent groups of 286 and 269 healthy controls. All participants were white continental individuals with French ancestry.

Results: Ht SNPs of CTLA-4 and TNFalpha genes were significantly associated with susceptibility to PBC. The progression rate of liver disease under ursodeoxycholic acid (UDCA) therapy was significantly linked to SNPs of TNFalpha and SLC4A2/anion exchanger 2 (AE2) genes. A multivariate Cox regression analysis including clinical and biochemical parameters showed that SLC4A2/AE2 variant was an independent prognostic factor.

Conclusions: These data point to a primary role of genes encoding regulators of the immune system in the susceptibility to PBC. They also demonstrate that allelic variations in TNFalpha and SLC4A2/AE2 have a significant impact on the evolutive profile of PBC under UDCA therapy.
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http://dx.doi.org/10.1016/j.jhep.2008.07.027DOI Listing
December 2008