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Hof WFJ, de Boer JF, Verkade HJ. Emerging drugs for the treatment of progressive familial intrahepatic cholestasis: a focus on phase II and III trials. Expert Opin Emerg Drugs 2024:1-16. [PMID: 38571480 DOI: 10.1080/14728214.2024.2336986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 03/27/2024] [Indexed: 04/05/2024]
Abstract
INTRODUCTION Progressive familial intrahepatic cholestasis (PFIC) is a group of disorders characterized by inappropriate bile formation, causing hepatic accumulation of bile acids and, subsequently, liver injury. Until recently, no approved treatments were available for these patients. AREAS COVERED Recent clinical trials for PFIC treatment have focused on intestine-restricted ileal bile acid transporter (IBAT) inhibitors. These compounds aim to reduce the pool size of bile acids by interrupting their enterohepatic circulation. Other emerging treatments in the pipeline include systemic IBAT inhibitors, synthetic bile acid derivatives, compounds targeting bile acid synthesis via the FXR/FGF axis, and chaperones/potentiators that aim to enhance the residual activity of the mutated transporters. EXPERT OPINION Substantial progress has been made in drug development for PFIC patients during the last couple of years. Although data concerning long-term efficacy are as yet only scarcely available, new therapies have demonstrated robust efficacy in a considerable fraction of patients at least on the shorter term. However, a substantial fraction of PFIC patients do not respond to these novel therapies and thus still requires surgical treatment, including liver transplantation before adulthood. Hence, there is still an unmet medical need for long-term effective medical, preferably non-surgical, treatment for all PFIC patients.
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Affiliation(s)
- Willemien F J Hof
- Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan Freark de Boer
- Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands
- Department of Laboratory Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - Henkjan J Verkade
- Department of Pediatrics, University Medical Center Groningen, Groningen, The Netherlands
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Sohail MI, Dönmez-Cakil Y, Szöllősi D, Stockner T, Chiba P. The Bile Salt Export Pump: Molecular Structure, Study Models and Small-Molecule Drugs for the Treatment of Inherited BSEP Deficiencies. Int J Mol Sci 2021; 22:E784. [PMID: 33466755 PMCID: PMC7830293 DOI: 10.3390/ijms22020784] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 02/07/2023] Open
Abstract
The bile salt export pump (BSEP/ABCB11) is responsible for the transport of bile salts from hepatocytes into bile canaliculi. Malfunction of this transporter results in progressive familial intrahepatic cholestasis type 2 (PFIC2), benign recurrent intrahepatic cholestasis type 2 (BRIC2) and intrahepatic cholestasis of pregnancy (ICP). Over the past few years, several small molecular weight compounds have been identified, which hold the potential to treat these genetic diseases (chaperones and potentiators). As the treatment response is mutation-specific, genetic analysis of the patients and their families is required. Furthermore, some of the mutations are refractory to therapy, with the only remaining treatment option being liver transplantation. In this review, we will focus on the molecular structure of ABCB11, reported mutations involved in cholestasis and current treatment options for inherited BSEP deficiencies.
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Affiliation(s)
| | - Yaprak Dönmez-Cakil
- Department of Histology and Embryology, Faculty of Medicine, Maltepe University, Maltepe, 34857 Istanbul, Turkey;
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse, 13A, 1090 Vienna, Austria;
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse, 13A, 1090 Vienna, Austria;
| | - Peter Chiba
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Waehringerstrasse, 10, 1090 Vienna, Austria
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Sohn MJ, Woo MH, Seong MW, Park SS, Kang GH, Moon JS, Ko JS. Benign Recurrent Intrahepatic Cholestasis Type 2 in Siblings with Novel ABCB11 Mutations. Pediatr Gastroenterol Hepatol Nutr 2019; 22:201-206. [PMID: 30899697 PMCID: PMC6416387 DOI: 10.5223/pghn.2019.22.2.201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/28/2018] [Accepted: 06/27/2018] [Indexed: 12/16/2022] Open
Abstract
Benign recurrent intrahepatic cholestasis (BRIC), a rare cause of cholestasis, is characterized by recurrent episodes of cholestasis without permanent liver damage. BRIC type 2 (BRIC2) is an autosomal recessive disorder caused by ABCB11 mutations. A 6-year-old girl had recurrent episodes of jaundice. At two months of age, jaundice and hepatosplenomegaly developed. Liver function tests showed cholestatic hepatitis. A liver biopsy revealed diffuse giant cell transformation, bile duct paucity, intracytoplasmic cholestasis, and periportal fibrosis. An ABCB11 gene study revealed novel compound heterozygous mutations, including c.2075+3A>G in IVS17 and p.R1221K. Liver function test results were normal at 12 months of age. At six years of age, steatorrhea, jaundice, and pruritus developed. Liver function tests improved following administration of phenylbutyrate and rifampicin. Her younger brother developed jaundice at two months of age and his genetic tests revealed the same mutations as his sister. This is the first report of BRIC2 confirmed by ABCB11 mutations in Korean siblings.
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Affiliation(s)
- Min Ji Sohn
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Min Hyung Woo
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Moon-Woo Seong
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Sup Park
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Gyeong Hoon Kang
- Department of Pathology, Seoul National University College of Medicine, Seoul, Korea
| | - Jin Soo Moon
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Jae Sung Ko
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
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Lin GZ, Qiu JW, Cheng Y, Lin WX, Song YZ. [Clinical and genetic analysis of an infant with progressive familial intrahepatic cholestasis type II]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2018; 20:758-764. [PMID: 30210030 PMCID: PMC7389172 DOI: 10.7499/j.issn.1008-8830.2018.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/16/2018] [Indexed: 06/08/2023]
Abstract
Progressive familial intrahepatic cholestasis type II (PFIC-2) is an autosomal recessive disorder caused by biallelic variants of ABCB11 gene. This paper reports the clinical and laboratory features of a pediatric patient with PFIC-2. The patient was a 2.4-month-old male infant with jaundice and hepatomegaly as the main clinical manifestations. The serum levels of total bilirubin, direct bilirubin and total bile acids were increased, while the serum γ-glutamyl transpeptidase (GGT) level was normal. Next generation sequencing revealed two missense variants, c.1493T>C(p.Ile498Thr) and c.1502T>G(p.Val501Gly), in the ABCB11 gene of the patient, which were inherited from his father and mother, respectively. The latter was a novel variant which was predicted to be pathogenic by using a variety of bioinformatic tools, and the affected p.Val501 residue was highly conserved in 112 homologous peptides.
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Affiliation(s)
- Gui-Zhi Lin
- Department of Pediatrics, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
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Vauthier V, Housset C, Falguières T. Targeted pharmacotherapies for defective ABC transporters. Biochem Pharmacol 2017; 136:1-11. [DOI: 10.1016/j.bcp.2017.02.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 02/23/2017] [Indexed: 02/07/2023]
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Lee SJ, Kim JE, Choe BH, Seo AN, Bae HI, Hwang SK. Early Diagnosis of ABCB11 Spectrum Liver Disorders by Next Generation Sequencing. Pediatr Gastroenterol Hepatol Nutr 2017; 20:114-123. [PMID: 28730136 PMCID: PMC5517378 DOI: 10.5223/pghn.2017.20.2.114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/21/2016] [Indexed: 01/27/2023] Open
Abstract
PURPOSE The goal of this study was the early diagnosis of ABCB11 spectrum liver disorders, especially those focused on benign recurrent intrahepatic cholestasis and progressive familial intrahepatic cholestasis. METHODS Fifty patients presenting neonatal cholestasis were evaluated to identify underlying etiologies. Genetic analysis was performed on patients suspected to have syndromic diseases or ABCB11 spectrum liver disorders. Two families with proven ABCB11 spectrum liver disorders were subjected to genetic analyses to confirm the diagnosis and were provided genetic counseling. Whole exome sequencing and Sanger sequencing were performed on the patients and the family members. RESULTS Idiopathic or viral hepatitis was diagnosed in 34%, metabolic disease in 20%, total parenteral nutrition induced cholestasis in 16%, extrahepatic biliary atresia in 14%, genetic disease in 10%, neonatal lupus in 2%, congenital syphilis in 2%, and choledochal cyst in 2% of the patients. The patient with progressive familial intrahepatic cholestasis had novel heterozygous mutations of ABCB11 c.11C>G (p.Ser4*) and c.1543A>G (p.Asn515Asp). The patient with benign recurrent intrahepatic cholestasis had homozygous mutations of ABCB11 c.1331T>C (p.Val444Ala) and heterozygous, c.3084A>G (p.Ala1028Ala). Genetic confirmation of ABCB11 spectrum liver disorder led to early liver transplantation in the progressive familial intrahepatic cholestasis patient. In addition, the atypically severe benign recurrent intrahepatic cholestasis patient was able to avoid unnecessary liver transplantation after genetic analysis. CONCLUSION ABCB11 spectrum liver disorders can be clinically indistinguishable as they share similar characteristics related to acute episodes. A comprehensive genetic analysis will facilitate optimal diagnosis and treatment.
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Affiliation(s)
- Su Jeong Lee
- Department of Pediatrics, Kyungpook National University School of Medicine, Daegu, Korea
| | - Jung Eun Kim
- Department of Pediatrics, Kyungpook National University School of Medicine, Daegu, Korea
| | - Byung-Ho Choe
- Department of Pediatrics, Kyungpook National University School of Medicine, Daegu, Korea
| | - An Na Seo
- Department of Pathology, Kyungpook National University School of Medicine, Daegu, Korea
| | - Han-Ik Bae
- Department of Pathology, Kyungpook National University School of Medicine, Daegu, Korea
| | - Su-Kyeong Hwang
- Department of Pediatrics, Kyungpook National University School of Medicine, Daegu, Korea
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Telbisz Á, Homolya L. Recent advances in the exploration of the bile salt export pump (BSEP/ABCB11) function. Expert Opin Ther Targets 2015; 20:501-14. [PMID: 26573700 DOI: 10.1517/14728222.2016.1102889] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The bile salt export pump (BSEP/ABCB11), residing in the apical membrane of hepatocyte, mediates the secretion of bile salts into the bile. A range of human diseases is associated with the malfunction of BSEP, including fatal hereditary liver disorders and mild cholestatic conditions. Manifestation of these diseases primarily depends on the mutation type; however, other factors such as hormonal changes and drug interactions can also trigger or influence the related diseases. AREAS COVERED Here, we summarize the recent knowledge on BSEP by covering its transport properties, cellular localization, regulation and major mutations/polymorphisms, as well as the hereditary and acquired diseases associated with BSEP dysfunction. We discuss the different model expression systems employed to understand the function of the BSEP variants, their drug interactions and the contemporary therapeutic interventions. EXPERT OPINION The limitations of the available model expression systems for BSEP result in controversial conclusions, and obstruct our deeper insight into BSEP deficiencies and BSEP-related drug interactions. The knowledge originating from different methodologies, such as clinical studies, molecular genetics, as well as in vitro and in silico modeling, should be integrated and harmonized. Increasing availability of robust molecular biological tools and our better understanding of the mechanism of BSEP deficiencies should make the personalized, mutation-based therapeutic interventions more attainable.
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Affiliation(s)
- Ágnes Telbisz
- a Institute of Enzymology, Research Centre for Natural Sciences , Hungarian Academy of Sciences , Magyar tudósok körútja 2, Budapest 1117 , Hungary
| | - László Homolya
- a Institute of Enzymology, Research Centre for Natural Sciences , Hungarian Academy of Sciences , Magyar tudósok körútja 2, Budapest 1117 , Hungary
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Galenko AV, Khlebnikov AF, Novikov MS, Pakalnis VV, Rostovskii NV. Recent advances in isoxazole chemistry. RUSSIAN CHEMICAL REVIEWS 2015. [DOI: 10.1070/rcr4503] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Baghdasaryan A, Chiba P, Trauner M. Clinical application of transcriptional activators of bile salt transporters. Mol Aspects Med 2014; 37:57-76. [PMID: 24333169 PMCID: PMC4045202 DOI: 10.1016/j.mam.2013.12.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 11/21/2013] [Accepted: 12/01/2013] [Indexed: 02/07/2023]
Abstract
Hepatobiliary bile salt (BS) transporters are critical determinants of BS homeostasis controlling intracellular concentrations of BSs and their enterohepatic circulation. Genetic or acquired dysfunction of specific transport systems causes intrahepatic and systemic retention of potentially cytotoxic BSs, which, in high concentrations, may disturb integrity of cell membranes and subcellular organelles resulting in cell death, inflammation and fibrosis. Transcriptional regulation of canalicular BS efflux through bile salt export pump (BSEP), basolateral elimination through organic solute transporters alpha and beta (OSTα/OSTβ) as well as inhibition of hepatocellular BS uptake through basolateral Na(+)-taurocholate cotransporting polypeptide (NTCP) represent critical steps in protection from hepatocellular BS overload and can be targeted therapeutically. In this article, we review the potential clinical implications of the major BS transporters BSEP, OSTα/OSTβ and NTCP in the pathogenesis of hereditary and acquired cholestatic syndromes, provide an overview on transcriptional control of these transporters by the key regulatory nuclear receptors and discuss the potential therapeutic role of novel transcriptional activators of BS transporters in cholestasis.
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Affiliation(s)
- Anna Baghdasaryan
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria; Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Peter Chiba
- Institute of Medical Chemistry, Medical University of Vienna, Austria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria.
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Defining the blanks--pharmacochaperoning of SLC6 transporters and ABC transporters. Pharmacol Res 2013; 83:63-73. [PMID: 24316454 PMCID: PMC4059943 DOI: 10.1016/j.phrs.2013.11.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 11/27/2013] [Accepted: 11/27/2013] [Indexed: 02/06/2023]
Abstract
SLC6 family members and ABC transporters represent two extremes: SLC6 transporters are confined to the membrane proper and only expose small segments to the hydrophilic milieu. In ABC transporters the hydrophobic core is connected to a large intracellular (eponymous) ATP binding domain that is comprised of two discontiguous repeats. Accordingly, their folding problem is fundamentally different. This can be gauged from mutations that impair the folding of the encoded protein and give rise to clinically relevant disease phenotypes: in SLC6 transporters, these cluster at the protein–lipid interface on the membrane exposed surface. Mutations in ABC-transporters map to the interface between nucleotide binding domains and the coupling helices, which provide the connection to the hydrophobic core. Folding of these mutated ABC-transporters can be corrected with ligands/substrates that bind to the hydrophobic core. This highlights a pivotal role of the coupling helices in the folding trajectory. In contrast, insights into pharmacochaperoning of SLC6 transporters are limited to monoamine transporters – in particular the serotonin transporter (SERT) – because of their rich pharmacology. Only ligands that stabilize the inward facing conformation act as effective pharmacochaperones. This indicates that the folding trajectory of SERT proceeds via the inward facing conformation. Mutations that impair folding of SLC6 family members can be transmitted as dominant or recessive alleles. The dominant phenotype of the mutation can be rationalized, because SLC6 transporters are exported in oligomeric form from the endoplasmic reticulum (ER). Recessive transmission requires shielding of the unaffected gene product from the mutated transporter in the ER. This can be accounted for by a chaperone-COPII (coatomer protein II) exchange model, where proteinaceous ER-resident chaperones engage various intermediates prior to formation of the oligomeric state and subsequent export from the ER. It is likely that the action of pharmacochaperones is contingent on and modulated by these chaperones.
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Pharmacological chaperones for enzyme enhancement therapy in genetic diseases. Pharm Pat Anal 2013; 2:109-24. [DOI: 10.4155/ppa.12.74] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pharmacological chaperone therapy (PCT) is a rather new approach consisting in targeting incorrectly folded proteins by small molecules, thus, facilitating the correct folding of the protein and inducing a recovery of its functionality. Many diseases result from mutations on specific genes; this patent review focuses on those pathologies where PCT has a potential application for enzymatic enhancement. Rare diseases are the main area where PCT has been applied and the most advanced compounds are aiming to cure lysosomal storage disorders such as Fabry, Pompe or Gaucher. Until now, most compounds used as pharmacological chaperones were based on substrate-like chemical structures but recently new nonsubstrate-like and non-inhibitory compounds have been disclosed for Gaucher and Pompe diseases. This initiates a new era for pharmacological chaperones with more diverse chemical structures and binding modes. This review covers the patents relating to enzyme enhancement on pharmacological chaperone therapy. Only an update is presented for Gaucher disease, where PCT is highly applied and recently reviewed.
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Underhaug J, Aubi O, Martinez A. Phenylalanine hydroxylase misfolding and pharmacological chaperones. Curr Top Med Chem 2012; 12:2534-45. [PMID: 23339306 PMCID: PMC3664513 DOI: 10.2174/1568026611212220008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 08/28/2012] [Accepted: 08/29/2012] [Indexed: 12/15/2022]
Abstract
Phenylketonuria (PKU) is a loss-of-function inborn error of metabolism. As many other inherited diseases the main pathologic mechanism in PKU is an enhanced tendency of the mutant phenylalanine hydroxylase (PAH) to misfold and undergo ubiquitin-dependent degradation. Recent alternative approaches with therapeutic potential for PKU aim at correcting the PAH misfolding, and in this respect pharmacological chaperones are the focus of increasing interest. These compounds, which often resemble the natural ligands and show mild competitive inhibition, can rescue the misfolded proteins by stimulating their renaturation in vivo. For PKU, a few studies have proven the stabilization of PKU-mutants in vitro, in cells, and in mice by pharmacological chaperones, which have been found either by using the tetrahydrobiopterin (BH(4)) cofactor as query structure for shape-focused virtual screening or by high-throughput screening of small compound libraries. Both approaches have revealed a number of compounds, most of which bind at the iron-binding site, competitively with respect to BH(4). Furthermore, PAH shares a number of ligands, such as BH(4), amino acid substrates and inhibitors, with the other aromatic amino acid hydroxylases: the neuronal/neuroendocrine enzymes tyrosine hydroxylase (TH) and the tryptophan hydroxylases (TPHs). Recent results indicate that the PAH-targeted pharmacological chaperones should also be tested on TH and the TPHs, and eventually be derivatized to avoid unwanted interactions with these other enzymes. After derivatization and validation in animal models, the PAH-chaperoning compounds represent novel possibilities in the treatment of PKU.
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Affiliation(s)
| | | | - Aurora Martinez
- Department of Biomedicine, and K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
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