The bile salt export pump (BSEP) plays an important role in biliary secretion. Mutations in ABCB11, the gene encoding BSEP, induce progressive familial intrahepatic cholestasis type 2 (PFIC2), which presents with severe jaundice and liver dysfunction. A less severe phenotype, called benign recurrent intrahepatic cholestasis type 2, is also known. About 200 missense mutations in ABCB11 have been reported. However, the phenotype–genotype correlation has not been clarified. Furthermore, the frequencies of ABCB11 mutations differ between Asian and European populations. We report a patient with PFIC2 carrying a homozygous ABCB11 mutation c.386G>A (p.C129Y) that is most frequently reported in Japan. The pathogenicity of BSEPC129Y has not been investigated. In this study, we performed the molecular analysis of this ABCB11 mutation using cells expressing BSEPC129Y. We found that trafficking of BSEPC129Y to the plasma membrane was impaired and that the expression of BSEPC129Y on the cell surface was significantly lower than that in the control. The amount of bile acids transported via BSEPC129Y was also significantly lower than that via BSEPWT. The transport activity of BSEPC129Y may be conserved because the amount of membrane BSEPC129Y corresponded to the uptake of taurocholate into membrane vesicles. In conclusion, we demonstrated that c.386G>A (p.C129Y) in ABCB11 was a causative mutation correlating with the phenotype of patients with PFIC2, impairment of biliary excretion from hepatocytes, and the absence of canalicular BSEP expression in liver histological assessments. Mutational analysis in ABCB11 could facilitate the elucidation of the molecular mechanisms underlying the development of intrahepatic cholestasis.
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Gerloff T, et al. The sister of P-glycoprotein represents the canalicular bile salt export pump of mammalian liver. J Biol Chem. 1998;273:10046–50. https://doi.org/10.1074/jbc.273.16.10046.
Jansen PL, et al. Hepatocanalicular bile salt export pump deficiency in patients with progressive familial intrahepatic cholestasis. Gastroenterology. 1999;117:1370–9. https://doi.org/10.1016/S0016-5085(99)70287-8.
Davit-Spraul A, et al. ATP8B1 and ABCB11 analysis in 62 children with normal gamma-glutamyl transferase progressive familial intrahepatic cholestasis (PFIC): phenotypic differences between PFIC1 and PFIC2 and natural history. Hepatology. 2010;51:1645–55. https://doi.org/10.1002/hep.23539.
de Vree JML, et al. Mutations in the MDR3 gene cause progressive familial intrahepatic cholestasis. Proc Natl Acad Sci USA. 1998;95:282–7.
Gonzales E, Spraul A, Jacquemin E. Clinical utility gene card for: progressive familial intrahepatic cholestasis type 2. Eur J Hum Genet. 2014;22. https://doi.org/10.1038/ejhg.2013.187.
Scheimann AO, et al. Mutations in bile salt export pump (ABCB11) in two children with progressive familial intrahepatic cholestasis and cholangiocarcinoma. J Pediatr. 2007;150:556–9. https://doi.org/10.1016/j.jpeds.2007.02.030.
Knisely AS, et al. Hepatocellular carcinoma in ten children under five years of age with bile salt export pump deficiency. Hepatology. 2006;44:478–86. https://doi.org/10.1002/hep.21287.
Strautnieks SS, et al. Severe bile salt export pump deficiency: 82 different ABCB11 mutations in 109 families. Gastroenterology. 2008;134:1203–14. https://doi.org/10.1053/j.gastro.2008.01.038.
Hayashi H, Takada T, Suzuki H, Akita H, Sugiyama Y. Two common PFIC2 mutations are associated with the impaired membrane trafficking of BSEP/ABCB11. Hepatology. 2005;41:916–24. https://doi.org/10.1002/hep.20627.
Hayashi H, Sugiyama Y. 4-phenylbutyrate enhances the cell surface expression and the transport capacity of wild-type and mutated bile salt export pumps. Hepatology. 2007;45:1506–16. https://doi.org/10.1002/hep.21630.
Togawa T, et al. Molecular genetic dissection and neonatal/infantile intrahepatic cholestasis using targeted next-generation sequencing. J Pediatr. 2016;171:171–7. https://doi.org/10.1016/j.jpeds.2016.01.006.
Park JS, Ko JS, Seo JK, Moon JS, Park SS. Clinical and ABCB11 profiles in Korean infants with progressive familial intrahepatic cholestasis. World J Gastroenterol. 2016;22:4901–7. https://doi.org/10.3748/wjg.v22.i20.4901.
Wang N-L, et al. The features of GGT in patients with ATP8B1 or ABCB11 deficiency improve the diagnostic efficiency. PloS ONE. 2016;11:e0153114 https://doi.org/10.1371/journal.pone.0153114.
Liu LY, Wang ZL, Wang XH, Zhu QR, Wang JS. ABCB11 gene mutations in Chinese children with progressive intrahepatic cholestasis and low gamma glutamyltransferase. Liver Int. 2010;30:809–15. https://doi.org/10.1111/j.1478-3231.2009.02112.x.
Ananthanarayanan M, Li Y. PFIC2 and ethnicity-specific bile salt export pump (BSEP, ABCB11) mutations: where do we go from here? Liver Int. 2010;30:777–9. https://doi.org/10.1111/j.1478-3231.2010.02227.x.
Verkade HJ, et al. Biliary atresia and other cholestatic childhood diseases: advances and future challenges. J Hepatol. 2016;65:631–42. https://doi.org/10.1016/j.jhep.2016.04.032.
Naoi S, et al. Improved liver function and relieved pruritus after 4-phenylbutyrate therapy in a patient with progressive familial intrahepatic cholestasis type 2. J Pediatr. 2014;164:1219–27. https://doi.org/10.1016/j.jpeds.2013.12.032. e1213.
Hayashi H, et al. AP2 adaptor complex mediates bile salt export pump internalization and modulates its hepatocanalicular expression and transport function. Hepatology. 2012;55:1889–1900. https://doi.org/10.1002/hep.25591.
Hayashi H, et al. Transport by vesicles of glycine- and taurine-conjugated bile salts and taurolithocholate 3-sulfate: a comparison of human BSEP with rat Bsep. Biochim Biophys Acta. 2005;1738:54–62. https://doi.org/10.1016/j.bbalip.2005.10.006.
Biasini M, et al. SWISS-MODEL: modelling protein tertiary and quaternary structure using evolutionary information. Nucleic Acids Res. 2014;42:W252–W258. https://doi.org/10.1093/nar/gku340.
Arnold K, Bordoli L, Kopp J, Schwede T. The SWISS-MODEL workspace: a web-based environment for protein structure homology modelling. Bioinformatics. 2006;22:195–201. https://doi.org/10.1093/bioinformatics/bti770.
Benkert P, Biasini M, Schwede T. Toward the estimation of the absolute quality of individual protein structure models. Bioinformatics. 2011;27:343–50. https://doi.org/10.1093/bioinformatics/btq662.
Evason K, et al. Morphologic findings in progressive familial intrahepatic cholestasis 2 (PFIC2): correlation with genetic and immunohistochemical studies. Am J Surg Pathol. 2011;35:687–96. https://doi.org/10.1097/PAS.0b013e318212ec87.
Stindt J, et al. Bile salt export pump-reactive antibodies form a polyclonal, multi-inhibitory response in antibody-induced bile salt export pump deficiency. Hepatology. 2016;63:524–37. https://doi.org/10.1002/hep.28311.
Maggiore G, et al. Relapsing features of bile salt export pump deficiency after liver transplantation in two patients with progressive familial intrahepatic cholestasis type 2. J Hepatol. 2010;53:981–6. https://doi.org/10.1016/j.jhep.2010.05.025.
Jara P, et al. Recurrence of bile salt export pump deficiency after liver transplantation. New Engl J Med. 2009;361:1359–67. https://doi.org/10.1056/NEJMoa0901075.
Lam C-W, et al. A patient with novel ABCB11 gene mutations with phenotypic transition between BRIC2 and PFIC2. J Hepatol. 2006;44:240–2. https://doi.org/10.1016/j.jhep.2005.09.013.
Takahashi A, et al. Gradual improvement of liver function after administration of ursodeoxycholic acid in an infant with a novel ABCB11 gene mutation with phenotypic continuum between BRIC2 and PFIC2. Eur J Gastroenterol Hepatol. 2007;19:942–6. https://doi.org/10.1097/MEG.0b013e3282ef4795.
Sambrotta M, et al. Mutations in TJP2 cause progressive cholestatic liver disease. Nat Genet. 2014;46:326–8. https://doi.org/10.1038/ng.2918.
Gomez-Ospina N, et al. Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis. Nat Commun. 2016;7:10713. https://doi.org/10.1038/ncomms10713.
Hayashi H, Sugiyama Y. Short-chain ubiquitination is associated with the degradation rate of a cell-surface-resident bile salt export pump (BSEP/ABCB11). Mol Pharmacol. 2009;75:143–50. https://doi.org/10.1124/mol.108.049288.
Aida K, Hayashi H, Inamura K, Mizuno T, Sugiyama Y. Differential roles of ubiquitination in the degradation mechanism of cell surface-resident bile salt export pump and multidrug resistance-associated protein 2. Mol Pharmacol. 2014;85:482–91. https://doi.org/10.1124/mol.113.091090.
Hayashi H, et al. Successful treatment with 4-phenylbutyrate in a patient with benign recurrent intrahepatic cholestasis type 2 refractory to biliary drainage and bilirubin absorption. Hepatol Res. 2016;46:192–200. https://doi.org/10.1111/hepr.12561.
Gonzales E, et al. Targeted pharmacotherapy in progressive familial intrahepatic cholestasis type 2: Evidence for improvement of cholestasis with 4-phenylbutyrate. Hepatology. 2015;62:558–66. https://doi.org/10.1002/hep.27767.
Gonzales E, et al. Successful mutation-specific chaperone therapy with 4-phenylbutyrate in a child with progressive familial intrahepatic cholestasis type 2. J Hepatol. 2012;57:695–8. https://doi.org/10.1016/j.jhep.2012.04.017.
Ito S, et al. Effects of 4-phenylbutyrate therapy in a preterm infant with cholestasis and liver fibrosis. Pediatr Int. 2016;58:506–9. https://doi.org/10.1111/ped.12839.
Hasegawa Y, et al. Intractable itch relieved by 4-phenylbutyrate therapy in patients with progressive familial intrahepatic cholestasis type 1. Orphanet J Rare Dis. 2014;9:89. https://doi.org/10.1186/1750-1172-9-89.
Wang R, et al. Compensatory role of P-glycoproteins in knockout mice lacking the bile salt export pump. Hepatology. 2009;50:948–56. https://doi.org/10.1002/hep.23089.
Goto K, et al. Bile salt export pump gene mutations in two Japanese patients with progressive familial intrahepatic cholestasis. J Pediatr Gastroenterol Nutr. 2003;36:647–50.
Shimizu H, et al. Living-related liver transplantation for siblings with progressive familial intrahepatic cholestasis 2, with novel genetic findings. Am J Transplant. 2011;11:394–8. https://doi.org/10.1111/j.1600-6143.2010.03397.x.
We thank Dr. Hiroko Fukushima, Dr. Aiko Sakai, and Dr. Hisato Suzuki for critical discussions. We also thank all the members of our laboratory for constructive comments, suggestions, and discussions. We would like to thank Enago (www.enago.jp) for the English language review. We would like to thank Editage (www.editage.jp) for English language editing.
KI is supported by JSPS KAKENHI Grant Number 17K16240. This work is supported by Japan Agency for Medical Research and Development, AMED, under Grant Number JP17ak0101036 to HH. This research is also funded by Japan Agency for Medical Research and development, AMED, to RS.
Conflict of interest
The authors declare that they have no conflict of interest.
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Imagawa, K., Hayashi, H., Sabu, Y. et al. Clinical phenotype and molecular analysis of a homozygous ABCB11 mutation responsible for progressive infantile cholestasis. J Hum Genet 63, 569–577 (2018). https://doi.org/10.1038/s10038-018-0431-1
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