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Lim YZ, Zhu M, Wang Y, Sharma T, Kelley S, Oertling E, Zhu H, Corbitt N. Pkd1l1-deficiency drives biliary atresia through ciliary dysfunction in biliary epithelial cells. J Hepatol 2024; 81:62-75. [PMID: 38460793 DOI: 10.1016/j.jhep.2024.02.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 02/07/2024] [Accepted: 02/29/2024] [Indexed: 03/11/2024]
Abstract
BACKGROUND & AIMS Syndromic biliary atresia is a cholangiopathy characterized by fibro-obliterative changes in the extrahepatic bile duct (EHBD) and congenital malformations including laterality defects. The etiology remains elusive and faithful animal models are lacking. Genetic syndromes provide important clues regarding the pathogenic mechanisms underlying the disease. We investigated the role of the gene Pkd1l1 in the pathophysiology of syndromic biliary atresia. METHODS Constitutive and conditional Pkd1l1 knockout mice were generated to explore genetic pathology as a cause of syndromic biliary atresia. We investigated congenital malformations, EHBD and liver pathology, EHBD gene expression, and biliary epithelial cell turnover. Biliary drainage was functionally assessed with cholangiography. Histology and serum chemistries were assessed after DDC (3,5-diethoxycarbony l-1,4-dihydrocollidine) diet treatment and inhibition of the ciliary signaling effector GLI1. RESULTS Pkd1l1-deficient mice exhibited congenital anomalies including malrotation and heterotaxy. Pkd1l1-deficient EHBDs were hypertrophic and fibrotic. Pkd1l1-deficient EHBDs were patent but displayed delayed biliary drainage. Pkd1l1-deficient livers exhibited ductular reaction and periportal fibrosis. After DDC treatment, Pkd1l1-deficient mice exhibited EHBD obstruction and advanced liver fibrosis. Pkd1l1-deficient mice had increased expression of fibrosis and extracellular matrix remodeling genes (Tgfα, Cdkn1a, Hb-egf, Fgfr3, Pdgfc, Mmp12, and Mmp15) and decreased expression of genes mediating ciliary signaling (Gli1, Gli2, Ptch1, and Ptch2). Primary cilia were reduced on biliary epithelial cells and altered expression of ciliogenesis genes occurred in Pkd1l1-deficient mice. Small molecule inhibition of the ciliary signaling effector GLI1 with Gant61 recapitulated Pkd1l1-deficiency. CONCLUSIONS Pkd1l1 loss causes both laterality defects and fibro-proliferative EHBD transformation through disrupted ciliary signaling, phenocopying syndromic biliary atresia. Pkd1l1-deficient mice function as an authentic genetic model for study of the pathogenesis of biliary atresia. IMPACT AND IMPLICATIONS The syndromic form of biliary atresia is characterized by fibro-obliteration of extrahepatic bile ducts and is often accompanied by laterality defects. The etiology is unknown, but Pkd1l1 was identified as a potential genetic candidate for syndromic biliary atresia. We found that loss of the ciliary gene Pkd1l1 contributes to hepatobiliary pathology in biliary atresia, exhibited by bile duct hypertrophy, reduced biliary drainage, and liver fibrosis in Pkd1l1-deficient mice. Pkd1l1-deficient mice serve as a genetic model of biliary atresia and reveal ciliopathy as an etiology of biliary atresia. This model will help scientists uncover new therapeutic approaches for patients with biliary atresia, while pediatric hepatologists should validate the diagnostic utility of PKD1L1 variants.
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Affiliation(s)
- Yi Zou Lim
- Children's Research Institute, Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Min Zhu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Simmons Comprehensive Cancer Center, Center for Regenerative Science and Medicine, Children's Research Institute Mouse Genome Engineering Core, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yunguan Wang
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229, USA
| | - Tripti Sharma
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Simmons Comprehensive Cancer Center, Center for Regenerative Science and Medicine, Children's Research Institute Mouse Genome Engineering Core, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shannon Kelley
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Estelle Oertling
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hao Zhu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Simmons Comprehensive Cancer Center, Center for Regenerative Science and Medicine, Children's Research Institute Mouse Genome Engineering Core, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Natasha Corbitt
- Children's Research Institute, Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
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Hellen DJ, Bennett A, Malla S, Klindt C, Rao A, Dawson PA, Karpen SJ. Liver-restricted deletion of the biliary atresia candidate gene Pkd1l1 causes bile duct dysmorphogenesis and ciliopathy. Hepatology 2023; 77:1274-1286. [PMID: 36645229 DOI: 10.1097/hep.0000000000000029] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 10/17/2022] [Indexed: 01/17/2023]
Abstract
BACKGROUND AND AIMS A recent multicenter genetic exploration of the biliary atresia splenic malformation syndrome identified mutations in the ciliary gene PKD1L1 as candidate etiologic contributors. We hypothesized that deletion of Pkd1l1 in developing hepatoblasts would lead to cholangiopathy in mice. APPROACH AND RESULTS CRISPR-based genome editing inserted loxP sites flanking exon 8 of the murine Pkd1l1 gene. Pkd1l1Fl/Fl cross-bred with alpha-fetoprotein-Cre expressing mice to generate a liver-specific intrahepatic Pkd1l1 -deficient model (LKO). From embryonic day 18 through week 30, control ( Fl/Fl ) and LKO mice were evaluated with standard serum chemistries and liver histology. At select ages, tissues were analyzed using RNA sequencing, immunofluorescence, and electron microscopy with a focus on biliary structures, peribiliary inflammation, and fibrosis. Bile duct ligation for 5 days of Fl/Fl and LKO mice was followed by standard serum and liver analytics. Histological analyses from perinatal ages revealed delayed biliary maturation and reduced primary cilia, with progressive cholangiocyte proliferation, peribiliary fibroinflammation, and arterial hypertrophy evident in 7- to 16-week-old LKO versus Fl/Fl livers. Following bile duct ligation, cholangiocyte proliferation, peribiliary fibroinflammation, and necrosis were increased in LKO compared with Fl/Fl livers. CONCLUSIONS Bile duct ligation of the Pkd1l1 -deficient mouse model mirrors several aspects of the intrahepatic pathophysiology of biliary atresia in humans including bile duct dysmorphogenesis, peribiliary fibroinflammation, hepatic arteriopathy, and ciliopathy. This first genetically linked model of biliary atresia, the Pkd1l1 LKO mouse, may allow researchers a means to develop a deeper understanding of the pathophysiology of this serious and perplexing disorder, including the opportunity to identify rational therapeutic targets.
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Affiliation(s)
- Dominick J Hellen
- Division of Pediatric Gastroenterology, Department of Pediatrics, Hepatology, and Nutrition, Children's Healthcare of Atlanta and Emory University School of Medicine, Atlanta, Georgia, USA
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A novel nonsense PKD1L1 variant cause heterotaxy syndrome with congenital asplenia in a Han Chinese patient. J Hum Genet 2022; 67:573-577. [PMID: 35691949 DOI: 10.1038/s10038-022-01053-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/21/2022] [Accepted: 05/24/2022] [Indexed: 11/08/2022]
Abstract
Heterotaxy syndrome is a very rare congenital disease, which is caused by the disorder of left-right asymmetry during visceral development. However, pathogenic genetic lesions are found in less than 20% of HS patients. In this cohort study, whole-exome sequencing was performed for 110 patients with situs inversus or situs ambiguous. We identified a novel nonsense variant in PKD1L1(c.1387 C > T; p.463Gln*) in a Chinese patient with heterotaxy syndrome and congenital asplenia. This homozygous variant caused the domain of PKD1L1 complete absence. To our knowledge, this novel variant is the first phenotype of congenital asplenia found in patients with PKD1L1 variants, and the first PKD1L1 variant found in China. Our findings expand the spectrum of PKD1L1 variants and provide support for PKD1L1 variant and congenital asplenia, and the critical role of PKD1L1 during left-right patterning in the Han Chinese population.
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Antony D, Gulec Yilmaz E, Gezdirici A, Slagter L, Bakey Z, Bornaun H, Tanidir IC, Van Dinh T, Brunner HG, Walentek P, Arnold SJ, Backofen R, Schmidts M. Spectrum of Genetic Variants in a Cohort of 37 Laterality Defect Cases. Front Genet 2022; 13:861236. [PMID: 35547246 PMCID: PMC9083912 DOI: 10.3389/fgene.2022.861236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
Laterality defects are defined by the perturbed left–right arrangement of organs in the body, occurring in a syndromal or isolated fashion. In humans, primary ciliary dyskinesia (PCD) is a frequent underlying condition of defective left–right patterning, where ciliary motility defects also result in reduced airway clearance, frequent respiratory infections, and infertility. Non-motile cilia dysfunction and dysfunction of non-ciliary genes can also result in disturbances of the left–right body axis. Despite long-lasting genetic research, identification of gene mutations responsible for left–right patterning has remained surprisingly low. Here, we used whole-exome sequencing with Copy Number Variation (CNV) analysis to delineate the underlying molecular cause in 35 mainly consanguineous families with laterality defects. We identified causative gene variants in 14 families with a majority of mutations detected in genes previously associated with PCD, including two small homozygous CNVs. None of the patients were previously clinically diagnosed with PCD, underlining the importance of genetic diagnostics for PCD diagnosis and adequate clinical management. Identified variants in non-PCD-associated genes included variants in PKD1L1 and PIFO, suggesting that dysfunction of these genes results in laterality defects in humans. Furthermore, we detected candidate variants in GJA1 and ACVR2B possibly associated with situs inversus. The low mutation detection rate of this study, in line with other previously published studies, points toward the possibility of non-coding genetic variants, putative genetic mosaicism, epigenetic, or environmental effects promoting laterality defects.
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Affiliation(s)
- Dinu Antony
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Elif Gulec Yilmaz
- Department of Medical Genetics, University of Health Sciences, Istanbul Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - Alper Gezdirici
- Department of Medical Genetics, University of Health Sciences, Istanbul Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - Lennart Slagter
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands
| | - Zeineb Bakey
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Helen Bornaun
- Department of Pediatric Cardiology, University of Health Sciences, Istanbul Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | | | - Tran Van Dinh
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Han G. Brunner
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands
- Maastricht University Medical Center and GROW School of Oncology and Development, Maastricht University, Maastricht, Netherlands
| | - Peter Walentek
- Renal Division, Department of Medicine, University Hospital Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS- Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Sebastian J. Arnold
- CIBSS- Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Rolf Backofen
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- CIBSS- Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Miriam Schmidts
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Faculty of Medicine, Freiburg, Germany
- CIBSS- Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- *Correspondence: Miriam Schmidts,
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Correa ARE, Naini K, Mishra P, Dadhwal V, Agarwal R, Shukla R, Kabra M, Gupta N. Utility of fetal whole exome sequencing in the etiological evaluation and outcome of nonimmune hydrops fetalis. Prenat Diagn 2021; 41:1414-1424. [PMID: 34302381 DOI: 10.1002/pd.6022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/21/2021] [Accepted: 07/19/2021] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Nonimmune hydrops fetalis (NIHF) has varied etiology. We assessed the etiological spectrum and evaluated the utility of fetal whole exome sequencing (fWES) for the diagnosis of NIHF. METHODS In this prospective cohort study, we evaluated antenatally diagnosed fetuses with NIHF between July 2018 and December 2019 according to the routine diagnostic algorithm. Fetuses that remained undiagnosed after routine NIHF workup were subjected to fetal chromosomal microarray and/or WES. Pregnancies were followed up for clinical outcomes. RESULTS Of the 45 fetuses, consanguinity and recurrent hydrops fetalis were observed in 13.3% (6/45) and 28.8% (13/45), respectively. Overall, an etiological diagnosis was possible in 75.5% (34/45) of fetuses, while the cause remained unknown in 24.4% (11/45). A genetic etiology was identified in 46.6% (21/45): aneuploidy and monogenic disorders in 28.8% (13/45) and 17.8% (8/45), respectively. fWES on 19 fetuses detected disease-causing variants in 42.1% (8/19). Nine novel variants were detected in RAPSN, ASCC1, NEB, PKD1L1, GUSB, and PIEZO1. Only 8.8% (4/45) of the cohort survived without morbidity. CONCLUSIONS This study describes the etiological spectrum and the disease-causing variants in an Indian cohort of hydropic fetuses.
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Affiliation(s)
- Alec Reginald Errol Correa
- Department of Pediatrics, Division of Genetics, All India Institute of Medical Sciences, New Delhi, India
| | - Kamal Naini
- Department of Pediatrics, Division of Genetics, All India Institute of Medical Sciences, New Delhi, India
| | - Pallavi Mishra
- Department of Pediatrics, Division of Genetics, All India Institute of Medical Sciences, New Delhi, India
| | - Vatsla Dadhwal
- Department of Obstetrics & Gynecology, All India Institute of Medical Sciences, New Delhi, India
| | - Ramesh Agarwal
- Department of Pediatrics, Division of Neonatology, All India Institute of Medical Sciences, New Delhi, India
| | - Rashmi Shukla
- Department of Pediatrics, Division of Genetics, All India Institute of Medical Sciences, New Delhi, India
| | - Madhulika Kabra
- Department of Pediatrics, Division of Genetics, All India Institute of Medical Sciences, New Delhi, India
| | - Neerja Gupta
- Department of Pediatrics, Division of Genetics, All India Institute of Medical Sciences, New Delhi, India
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