Deleterious Variants in ABCC12 are Detected in Idiopathic Chronic Cholestasis and Cause Intrahepatic Bile Duct Loss in Model Organisms
The etiology of cholestasis remains unknown in many children. We surveyed the genome of children with chronic cholestasis for variants in genes not previously associated with liver disease and validated their biological relevance in zebrafish and murine models. Whole-exome (n = 4) and candidate gene...
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Published in | Gastroenterology (New York, N.Y. 1943) Vol. 161; no. 1; pp. 287 - 300.e16 |
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Main Authors | , , , , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
01.07.2021
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Subjects | |
Online Access | Get full text |
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Summary: | The etiology of cholestasis remains unknown in many children. We surveyed the genome of children with chronic cholestasis for variants in genes not previously associated with liver disease and validated their biological relevance in zebrafish and murine models.
Whole-exome (n = 4) and candidate gene sequencing (n = 89) was completed on 93 children with cholestasis and normal serum γ-glutamyl transferase (GGT) levels without pathogenic variants in genes known to cause low GGT cholestasis such as ABCB11 or ATP8B1. CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 genome editing was used to induce frameshift pathogenic variants in the candidate gene in zebrafish and mice.
In a 1-year-old female patient with normal GGT cholestasis and bile duct paucity, we identified a homozygous truncating pathogenic variant (c.198delA, p.Gly67Alafs∗6) in the ABCC12 gene (NM_033226). Five additional rare ABCC12 variants, including a pathogenic one, were detected in our cohort. ABCC12 encodes multidrug resistance-associated protein 9 (MRP9) that belongs to the adenosine 5ʹ-triphosphate–binding cassette transporter C family with unknown function and no previous implication in liver disease. Immunohistochemistry and Western blotting revealed conserved MRP9 protein expression in the bile ducts in human, mouse, and zebrafish. Zebrafish abcc12-null mutants were prone to cholangiocyte apoptosis, which caused progressive bile duct loss during the juvenile stage. MRP9-deficient mice had fewer well-formed interlobular bile ducts and higher serum alkaline phosphatase levels compared with wild-type mice. They exhibited aggravated cholangiocyte apoptosis, hyperbilirubinemia, and liver fibrosis upon cholic acid challenge.
Our work connects MRP9 with bile duct homeostasis and cholestatic liver disease for the first time. It identifies a potential therapeutic target to attenuate bile acid-induced cholangiocyte injury.
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ABCC12 encodes multidrug resistance-associated protein 9 that is important for maintaining cholangiocyte health in zebrafish and mice. Pathogenic variants in this gene are associated with intrahepatic bile duct loss in patients with chronic cholestasis. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Duc-Hung Pham, PhD (Conceptualization: Supporting; Data curation: Lead; Formal analysis: Lead; Investigation: Lead; Methodology: Lead; Validation: Lead; Writing – original draft preparation: Lead). Ramesh Kudira, PhD (Conceptualization: Supporting; Data curation: Lead; Formal analysis: Lead; Investigation: Lead; Methodology: Lead; Validation: Lead; Writing – revision draft: Lead). Lingfen Xu, MD (Investigation: Supporting; Methodology: Supporting; Validation: Supporting; Writing – original draft preparation: Supporting). C. Alexander Valencia, PhD (Conceptualization: Supporting; Data curation: Lead; Formal analysis: Lead; Investigation: Supporting; Methodology: Supporting; Writing - original draft preparation: Supporting). Jillian L. Ellis, MS (Formal analysis: Supporting; Investigation: Supporting; Validation: Supporting; Methodology: Supporting; Writing – review and editing: Supporting). Tiffany Shi, BS (Formal analysis: Supporting; Investigation: Supporting). Kimberley J. Evason, MD/PhD (Formal analysis: Supporting). Immaculeta Osuji, MS (Investigation: Supporting). Nelson Matuschek, MS (Formal analysis: Supporting; Investigation: Supporting). Liva Pfuhler, (Investigation: Supporting). Mary Mullen, PhD (Investigation: Supporting), Sujit K. Mohanty, PhD (Investigation: Supporting). Ammar Husami, BS (Data curation: Supporting; Formal analysis: Supporting; Investigation: Supporting; Writing – review and editing: Supporting). Laura N. Bull, PhD (Formal analysis: Supporting; Writing – review and editing: Supporting). Kejian Zhang, PhD (Conceptualization: Supporting; Formal analysis: Supporting; Methodology: Supporting; Resources: Supporting; Writing – review and editing: Supporting). Sami Wali, MD (Conceptualization: Supporting; Resources: Supporting). Chunyue Yin, PhD (Conceptualization: Lead; Formal analysis: Supporting; Investigation: Supporting; Resources: Lead; Data Curation: Supporting; Writing – original draft preparation: Lead; Writing – review and editing: Lead; Supervision: Lead; Project administration: Lead; Funding acquisition: Lead). Alexander Miethke, MD (Conceptualization: Lead; Formal analysis: Supporting; Investigation: Supporting; Resources: Lead; Data Curation: Supporting; Writing – original draft preparation: Lead; Writing – review and editing: Lead; Supervision: Lead; Project administration: Lead; Funding acquisition: Lead). CRediT Authorship Contributions |
ISSN: | 0016-5085 1528-0012 |
DOI: | 10.1053/j.gastro.2021.03.026 |