RESUMO
Haploinsufficiency of JAG1 is the primary cause of Alagille syndrome (ALGS), a rare, multisystem disorder. The identification of JAG1 intronic variants outside of the canonical splice region as well as missense variants, both of which lead to uncertain associations with disease, confuses diagnostics. Strategies to determine whether these variants affect splicing include the study of patient RNA or minigene constructs, which are not always available or can be laborious to design, as well as the utilization of computational splice prediction tools. These tools, including SpliceAI and Pangolin, use algorithms to calculate the probability that a variant results in a splice alteration, expressed as a Δ score, with higher Δ scores (>0.2 on a 0-1 scale) positively correlated with aberrant splicing. We studied the consequence of 10 putative splice variants in ALGS patient samples through RNA analysis and compared this to SpliceAI and Pangolin predictions. We identified eight variants with aberrant splicing, seven of which had not been previously validated. Combining these data with non-canonical and missense splice variants reported in the literature, we identified a predictive threshold for SpliceAI and Pangolin with high sensitivity (Δ score >0.6). Moreover, we showed reduced specificity for variants with low Δ scores (<0.2), highlighting a limitation of these tools that results in the misidentification of true splice variants. These results improve genomic diagnostics for ALGS by confirming splice effects for seven variants and suggest that the integration of splice prediction tools with RNA analysis is important to ensure accurate clinical variant classifications.
Assuntos
Síndrome de Alagille , Proteína Jagged-1 , Síndrome de Alagille/genética , Síndrome de Alagille/diagnóstico , Humanos , Proteína Jagged-1/genética , Splicing de RNA/genética , Processamento Alternativo/genética , Biologia Computacional/métodosRESUMO
BACKGROUND: Alagille syndrome (ALGS) is a rare autosomal dominant genetic disease caused by pathogenic variants in two genes: Jagged Canonical Notch Ligand 1 (JAG1) and Notch Receptor 2 (NOTCH2). It is characterized by phenotypic variability and incomplete penetrance with multiorgan clinical signs. METHODS: Using Next Generation Sequencing (NGS), we analyzed a panel of liver-disease-related genes in a population of 230 patients with cholestasis and hepatopathies. For the rare variants, bioinformatics predictions and pathogenicity classification were performed. RESULTS: We identified eleven rare NOTCH2 variants in 10 patients, two variants being present in the same patient. Ten variants had never been described before in the literature. It was possible to classify only two null variants as pathogenic, whereas the most of variants were missense (8 out of 11) and were classified as uncertain significance variants (USVs). Among patients with ALGS suspicion, two carried null variants, two carried variants predicted to be pathogenic by bioinformatics, one carried a synonymous variant and variants in glycosylation-related genes, and two carried variants predicted as benign in the PEST domain. CONCLUSIONS: Our results increased the knowledge about NOTCH2 variants and the related phenotype, allowing us to improve the genetic diagnosis of ALGS.
Assuntos
Síndrome de Alagille , Receptor Notch2 , Humanos , Síndrome de Alagille/genética , Receptor Notch2/genética , Masculino , Feminino , Lactente , Fenótipo , Criança , Pré-Escolar , Sequenciamento de Nucleotídeos em Larga Escala , Proteína Jagged-1/genética , Mutação de Sentido Incorreto , Mutação , AdolescenteRESUMO
In fetal development, tissue interaction such as the interplay between blood vessel (BV) and epithelial tissue is crucial for organogenesis. Here we recapitulate the spatial arrangement between liver epithelial tissue and the portal vein to observe the formation of intrahepatic bile ducts (BDs) from human induced pluripotent stem cells (hiPSC). We co-culture hiPSC-liver progenitors on the artificial BV consisting of immature smooth muscle cells and endothelial cells, both derived from hiPSCs. After 3 weeks, liver progenitors within hiPSC-BV-incorporated liver organoids (BVLO) differentiate to cholangiocytes and acquire epithelial characteristics, including intercellular junctions, microvilli on the apical membrane, and secretory functions. Furthermore, liver surface transplanted-BVLO temporarily attenuates cholestatic injury symptoms. Single cell RNA sequence analysis suggests that BD interact with the BV in BVLO through TGFß and Notch pathways. Knocking out JAG1 in hiPSC-BV significantly attenuates bile duct formation, highlighting BVLO potential as a model for Alagille syndrome, a congenital biliary disease. Overall, we develop a novel 3D co-culture method that successfully establishes functional human BDs by emulating liver epithelial-BV interaction.
Assuntos
Diferenciação Celular , Técnicas de Cocultura , Células-Tronco Pluripotentes Induzidas , Proteína Jagged-1 , Fígado , Organoides , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Organoides/metabolismo , Organoides/citologia , Fígado/citologia , Fígado/metabolismo , Fígado/irrigação sanguínea , Técnicas de Cocultura/métodos , Proteína Jagged-1/metabolismo , Proteína Jagged-1/genética , Síndrome de Alagille/genética , Síndrome de Alagille/metabolismo , Animais , Ductos Biliares Intra-Hepáticos/citologia , Ductos Biliares Intra-Hepáticos/metabolismo , Vasos Sanguíneos/citologia , Vasos Sanguíneos/metabolismo , Camundongos , Receptores Notch/metabolismo , Receptores Notch/genética , Células Endoteliais/metabolismo , Células Endoteliais/citologia , Ductos Biliares/citologia , Ductos Biliares/metabolismo , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/citologia , Fator de Crescimento Transformador beta/metabolismoRESUMO
BACKGROUND: Alagille syndrome (ALGS) is a multisystem genetic disorder frequently characterized by hepatic manifestations. This study analyzed the clinical, pathological, and molecular genetic features of ALGS to improve the efficiency of clinical diagnosis. METHODS: We retrospectively analyzed the clinical manifestations, pathological examination findings, and genetic testing results of 17 children diagnosed with ALGS based on the revised criteria and hospitalized at our center from January 2012 to January 2022. RESULTS: The clinical manifestations are as follows: Cholestasis (16/17, 94%), characteristic facies (15/17, 88%), heart disease (12/16, 75%), butterfly vertebrae (12/17, 71%) and posterior embryotoxon (7/12, 58%). Among the 15 patients who underwent liver pathology examination, 13 (87%) were found to have varying degrees of bile duct paucity. Genetic testing was performed on 15 children, and pathogenic variants of the jagged canonical Notch ligand 1 (JAG1) gene were identified in 13 individuals, including 4 novel variants. No pathogenic variant in the notch homolog 2 (NOTCH2) gene were identified, and 2 children exhibited none of the aforementioned gene pathogenic variants. The median follow-up duration was 7 years. Of the remaining 15 patients (excluding 2 lost to follow-up), 11 remained stable, 4 deteriorated, and no patient died during the follow-up period. CONCLUSIONS: Among children diagnosed with ALGS, cholestasis stands as the most common feature. To minimize the risk of misdiagnosis, genetic testing should be performed on children exhibiting cholestasis, followed by the application of the revised diagnostic criteria for ALGS. While pharmacological therapy has shown effectiveness for ALGS patients, liver transplantation may be considered in instances of severe pruritus.
Assuntos
Síndrome de Alagille , Testes Genéticos , Proteína Jagged-1 , Humanos , Síndrome de Alagille/genética , Síndrome de Alagille/diagnóstico , Masculino , Feminino , Estudos Retrospectivos , Pré-Escolar , Lactente , Proteína Jagged-1/genética , Criança , Colestase/genéticaRESUMO
PURPOSE: To explore patterns of disease expression in Alagille syndrome (ALGS). METHODS: Patients underwent ophthalmic examination, optical coherence tomography (OCT) imaging, fundus intravenous fluorescein angiography (IVFA), perimetry and full-field electroretinograms (ffERGs). An adult ALGS patient had multimodal imaging and specialized perimetry. RESULTS: The proband (P1) had a heterozygous pathogenic variant in JAG1; (p.Gln410Ter) and was incidentally diagnosed at age 7 with a superficial retinal hemorrhage, vascular tortuosity, and midperipheral pigmentary changes. The hemorrhage recurred 15 months later. Her monozygotic twin sister (P2) had a retinal hemorrhage at the same location at age 11. Visual acuities for both patients were 20/30 in each eye. IVFA was normal. OCT showed thinning of the outer nuclear in the peripapillary retina. A ffERG showed normal cone-mediated responses in P1 (rod-mediated ERGs not documented), normal ffERGs in P2. Coagulation and liver function were normal. An unrelated 42-year-old woman with a de-novo pathogenic variant (p. Gly386Arg) in JAG1 showed a similar pigmentary retinopathy and hepatic vascular anomalies; rod and cone function was normal across large expanses of structurally normal retina that sharply transitioned to a blind atrophic peripheral retina. CONCLUSION: Nearly identical recurrent intraretinal hemorrhages in monozygotic twins with ALGS suggest a shared subclinical microvascular abnormality. We hypothesize that the presence of large areas of functionally and structurally intact retina surrounded by severe chorioretinal degeneration, is against a predominant involvement of JAG1 in the function of the neurosensory retina, and that instead, primary abnormalities of chorioretinal vascular development and/or homeostasis may drive the peculiar phenotypes.
Assuntos
Síndrome de Alagille , Eletrorretinografia , Angiofluoresceinografia , Proteína Jagged-1 , Fenótipo , Hemorragia Retiniana , Tomografia de Coerência Óptica , Humanos , Feminino , Síndrome de Alagille/genética , Síndrome de Alagille/complicações , Síndrome de Alagille/diagnóstico , Proteína Jagged-1/genética , Adulto , Hemorragia Retiniana/diagnóstico , Hemorragia Retiniana/genética , Criança , Masculino , Acuidade Visual/fisiologia , Gêmeos Monozigóticos/genética , Testes de Campo Visual , Retina/patologia , Retina/fisiopatologiaRESUMO
Pathogenic variants in the JAG1 gene are a primary cause of the multi-system disorder Alagille syndrome. Although variant detection rates are high for this disease, there is uncertainty associated with the classification of missense variants that leads to reduced diagnostic yield. Consequently, up to 85% of reported JAG1 missense variants have uncertain or conflicting classifications. We generated a library of 2,832 JAG1 nucleotide variants within exons 1-7, a region with a high number of reported missense variants, and designed a high-throughput assay to measure JAG1 membrane expression, a requirement for normal function. After calibration using a set of 175 known or predicted pathogenic and benign variants included within the variant library, 486 variants were characterized as functionally abnormal (n = 277 abnormal and n = 209 likely abnormal), of which 439 (90.3%) were missense. We identified divergent membrane expression occurring at specific residues, indicating that loss of the wild-type residue itself does not drive pathogenicity, a finding supported by structural modeling data and with broad implications for clinical variant classification both for Alagille syndrome and globally across other disease genes. Of 144 uncertain variants reported in patients undergoing clinical or research testing, 27 had functionally abnormal membrane expression, and inclusion of our data resulted in the reclassification of 26 to likely pathogenic. Functional evidence augments the classification of genomic variants, reducing uncertainty and improving diagnostics. Inclusion of this repository of functional evidence during JAG1 variant reclassification will significantly affect resolution of variant pathogenicity, making a critical impact on the molecular diagnosis of Alagille syndrome.
Assuntos
Síndrome de Alagille , Proteína Jagged-1 , Mutação de Sentido Incorreto , Síndrome de Alagille/genética , Proteína Jagged-1/genética , Humanos , Éxons/genéticaRESUMO
PURPOSE OF REVIEW: To highlight recent advances in pediatric cholestatic liver disease, including promising novel prognostic markers and new therapies. FINDINGS: Additional genetic variants associated with the progressive familial intrahepatic cholestasis (PFIC) phenotype and new genetic cholangiopathies, with an emerging role of ciliopathy genes, are increasingly being identified. Genotype severity predicts outcomes in bile salt export pump (BSEP) deficiency, and post-biliary diversion serum bile acid levels significantly affect native liver survival in BSEP and progressive familial intrahepatic cholestasis type 1 (FIC1 deficiency) patients. Heterozygous variants in the MDR3 gene have been associated with various cholestatic liver disease phenotypes in adults. Ileal bile acid transporter (IBAT) inhibitors, approved for pruritus in PFIC and Alagille Syndrome (ALGS), have been associated with improved long-term quality of life and event-free survival. SUMMARY: Next-generation sequencing (NGS) technologies have revolutionized diagnostic approaches, while discovery of new intracellular signaling pathways show promise in identifying therapeutic targets and personalized strategies. Bile acids may play a significant role in hepatic damage progression, suggesting their monitoring could guide cholestatic liver disease management. IBAT inhibitors should be incorporated early into routine management algorithms for pruritus. Data are emerging as to whether IBAT inhibitors are impacting disease biology and modifying the natural history of the cholestasis.
Assuntos
Colestase Intra-Hepática , Humanos , Criança , Colestase Intra-Hepática/genética , Colestase Intra-Hepática/diagnóstico , Colestase Intra-Hepática/terapia , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Ácidos e Sais Biliares/metabolismo , Ácidos e Sais Biliares/sangue , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/genética , Síndrome de Alagille/terapia , Fenótipo , Prognóstico , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
Alagille syndrome (ALGS) is an autosomal dominant, multisystem disorder that typically presents with cholestasis, cardiac, ocular, skeletal, vascular and renal abnormalities, and distinct facial features. Most cases are due to variants in the JAG1 gene, with only a small percentage involving a complete gene deletion. OBJECTIVE: to contribute to the phenotype delineation and interpretation of a microdeletion not previously described in the literature on chromosome 20. CLINICAL CASE: A 4-month-old female patient was diagnosed with a heart murmur. An echocardiogram revealed pulmonary artery stenosis, which, combined with a prominent forehead observed on physical examination, determined her referral to clinical genetics. Because ALGS was suspected, complementary studies were performed, revealing butterfly vertebras and a genetic panel identified a pathogenic heterozygous deletion, encompassing the entire coding sequence of the JAG1 gene. To rule out a more extensive deletion, a chromosome microarray was performed, confirming a pathogenic microdeletion on chromosome 20 of 378 kb (arr[GRCh37] 20p12.2(10414643_10792802)x1). CONCLUSIONS: A targeted sequencing panel followed by confirmation with a chromosome microarray allowed the identification and delineation of a pathogenic microdeletion not previously reported in the literature, including the complete JAG1 gene in a Chilean patient whose phenotype is consistent with ALGS.
Assuntos
Síndrome de Alagille , Deleção de Genes , Proteína Jagged-1 , Humanos , Síndrome de Alagille/genética , Síndrome de Alagille/diagnóstico , Proteína Jagged-1/genética , Feminino , Lactente , FenótipoRESUMO
Alagille syndrome (ALGS) is an autosomal dominant, multisystemic disorder due to haploinsufficiency in JAG1 or less frequently, mutations in NOTCH2. The disease has been difficult to diagnose and treat due to variable expression. The generation of this iPSC line (TRNDi036-A) carrying a heterozygous mutation (p.Cys693*) in the JAG1 gene provides a means of studying the disease and developing novel therapeutics towards patient treatment.
Assuntos
Síndrome de Alagille , Heterozigoto , Células-Tronco Pluripotentes Induzidas , Proteína Jagged-1 , Mutação , Síndrome de Alagille/genética , Humanos , Proteína Jagged-1/genética , Proteína Jagged-1/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Linhagem Celular , Masculino , FemininoRESUMO
INTRODUCTION: Alagille syndrome (AGS) is a genetic disease with multisystemic affection, including ocular manifestations. Recently, a high frequency of posterior segment findings, including macular changes, has been reported. This publication aims to report an unusual finding of macular atrophy and a focal choroidal excavation in a patient with JAG1 related AGS. METHODS: Case report. RESULTS: This publication describes an atypical presentation of focal choroidal excavation (FCE) and unilateral macular atrophy in a 7-year-old male with Alagille syndrome (AGS). Genetic analysis revealed a pathogenic variant in the JAG1 gene. Ophthalmological examination and imaging findings demonstrated characteristic ocular manifestations of AGS, including posterior embryotoxon, chorioretinal atrophy, and thinning of the choroid. CONCLUSION: The presence of FCE in AGS is uncommon, and the underlying mechanisms remain unclear. Further exploration of similar cases is necessary to better understand the evolution and visual prognosis in patients with AGS and FCE.
This case report highlights the presence of focal choroidal excavation and unilateral macular atrophy in a patient with Alagille syndrome. The genetic analysis identified a pathogenic variant in the JAG1 gene.
Assuntos
Síndrome de Alagille , Proteína Jagged-1 , Humanos , Síndrome de Alagille/genética , Síndrome de Alagille/complicações , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/patologia , Proteína Jagged-1/genética , Masculino , Criança , Tomografia de Coerência Óptica , Doenças da Coroide/genética , Doenças da Coroide/diagnóstico , Angiofluoresceinografia , Acuidade Visual/fisiologia , Atrofia , Macula Lutea/patologia , Macula Lutea/anormalidades , Corioide/patologia , Corioide/anormalidadesRESUMO
Alagille syndrome (AGS) is a genetic disorder due to mutations in the JAGGED 1 or NOTCH 2 genes leading to multisystemic manifestations. Though these patients are at risk of developing various liver tumours, no cases of hepatoblastoma among young children with cirrhosis in AGS have been reported. We report a male toddler, with cirrhosis due to AGS who developed a hepatoblastoma. He underwent a liver transplant for decompensated chronic liver disease with marked pruritus, very high alpha-fetoprotein levels and malignant liver lesions on positron emission tomography CT. His explant histology revealed a paucity of bile ducts and liver lesions turned out to be hepatoblastoma for which he received postoperative chemotherapy. The genetic testing sent before transplantation confirmed the clinical diagnosis of AGS. Hepatoblastoma should be suspected in any child with AGS presenting with a right upper quadrant mass even in the setting of chronic liver disease.
Assuntos
Síndrome de Alagille , Hepatoblastoma , Neoplasias Hepáticas , Humanos , Masculino , Lactente , Pré-Escolar , Síndrome de Alagille/complicações , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/genética , Hepatoblastoma/complicações , Hepatoblastoma/diagnóstico , Hepatoblastoma/genética , Tomografia Computadorizada por Raios X , Neoplasias Hepáticas/complicações , Cirrose Hepática/complicaçõesRESUMO
BACKGROUND AND AIM: Advances in molecular genetics have uncovered causative genes responsible for neonatal cholestasis. Panel-based next-generation sequencing has been used clinically in infants with neonatal cholestasis. We aimed to evaluate the clinical application of single-gene testing and next-generation sequencing and to develop a diagnostic algorithm for neonatal intrahepatic cholestasis. METHODS: From January 2010 to July 2021, patients suspected of having neonatal intrahepatic cholestasis were tested at the Seoul National University Hospital. If there was a clinically suspected disease, single-gene testing was performed. Alternatively, if it was clinically difficult to differentiate, a neonatal cholestasis gene panel test containing 34 genes was performed. RESULTS: Of the total 148 patients examined, 49 (33.1%) were received a confirmed genetic diagnosis, including 14 with Alagille syndrome, 14 with neonatal intrahepatic cholestasis caused by citrin deficiency, 7 with Dubin-Johnson syndrome, 5 with arthrogryposis-renal dysfunction-cholestasis syndrome, 5 with progressive familial intrahepatic cholestasis type II, 1 with Rotor syndrome, 1 with Niemann-Pick disease type C, 1 with Kabuki syndrome, and 1 with Phenylalanyl-tRNA synthetase subunit alpha mutation. Sixteen novel pathogenic or likely pathogenic variants of neonatal cholestasis were observed in this study. Based on the clinical characteristics and laboratory findings, we developed a diagnostic algorithm for neonatal intrahepatic cholestasis by integrating single-gene testing and next-generation sequencing. CONCLUSIONS: Alagille syndrome and neonatal intrahepatic cholestasis caused by citrin deficiency were the most common diseases associated with genetic neonatal cholestasis. Single-gene testing and next-generation sequencing are important and complementary tools for the diagnosis of genetic neonatal cholestasis.
Assuntos
Algoritmos , Colestase Intra-Hepática , Testes Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Colestase Intra-Hepática/genética , Colestase Intra-Hepática/diagnóstico , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Recém-Nascido , Testes Genéticos/métodos , Masculino , Feminino , Síndrome de Alagille/genética , Síndrome de Alagille/diagnóstico , LactenteRESUMO
Notch signaling controls multiple aspects of embryonic development and adult homeostasis. Alagille syndrome is usually caused by a single mutation in the jagged canonical Notch ligand 1 (JAG1), and manifests with liver disease and cardiovascular symptoms that are a direct consequence of JAG1 haploinsufficiency. Recent insights into Jag1/Notch-controlled developmental and homeostatic processes explain how pathology develops in the hepatic and cardiovascular systems and, together with recent elucidation of mechanisms modulating liver regeneration, provide a basis for therapeutic efforts. Importantly, disease presentation can be regulated by genetic modifiers, that may also be therapeutically leverageable. Here, we summarize recent insights into how Jag1 controls processes of relevance to Alagille syndrome, focused on Jag1/Notch functions in hepatic and cardiovascular development and homeostasis.
Assuntos
Síndrome de Alagille , Humanos , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/genética , Síndrome de Alagille/terapia , Proteínas Serrate-Jagged , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Ligação ao Cálcio/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteína Jagged-1/genéticaRESUMO
Alagille Syndrome (ALGS) is a complex genetic disorder characterized by cholestasis, congenital cardiac anomalies, and butterfly vertebrae. The variable phenotypic expression of ALGS can lead to challenges in accurately diagnosing affected infants, potentially resulting in misdiagnoses or underdiagnoses. This study highlights novel JAG1 gene mutations in two cases of ALGS. The first case with a novel p.Pro325Leufs*87 variant was diagnosed at 2 months of age and exhibited a favorable prognosis and an unexpected manifestation of congenital hypothyroidism. Before the age of 2, the second patient was incorrectly diagnosed with liver structural abnormalities, necessitating extensive treatment. In addition, he exhibited delays in language acquisition that may have been a result of SNAP25 haploinsufficiency. The identification of ALGS remains challenging, highlighting the importance of early detection and genetic testing for effective patient management. The variant p.Pro325Leufs*87 is distinct from reported variants linked to congenital hypothyroidism in ALGS patients, thereby further confirming the clinical and genetic complexity of ALGS. This emphasizes the critical need for individualized and innovative approaches to diagnosis and medical interventions, uniquely intended to address the complexity of this syndrome.
Assuntos
Síndrome de Alagille , Hipotireoidismo Congênito , Humanos , Lactente , Masculino , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/genética , China , Hipotireoidismo Congênito/genética , Testes Genéticos , Proteína Jagged-1/genéticaRESUMO
Gallbladder and biliary diseases (GBDs) are one of the most common digestive diseases. The connections between GBDs and several organs other than the liver have gradually surfaced accompanied by the changes in people's diet structure and the continuous improvement of medical diagnosis technology. Among them, cholecardia syndrome that takes the heart as the important target of GBDs complications has been paid close attention. However, there are still no systematic report about its corresponding clinical manifestations and pathogenesis. This review summarized recent reported types of cholecardia syndrome and found that arrhythmia, myocardial injury, acute coronary syndrome and heart failure are common in the general population. Besides, the clinical diagnosis rate of intrahepatic cholestasis of pregnancy (ICP) and Alagille syndrome associated with gene mutation is also increasing. Accordingly, the underlying pathogenesis including abnormal secretion of bile acid, gene mutation, translocation and deletion (JAG1, NOTCH2, ABCG5/8 and CYP7A1), nerve reflex and autonomic neuropathy were further revealed. Finally, the potential treatment measures and clinical medication represented by ursodeoxycholic acid were summarized to provide assistance for clinical diagnosis and treatment.
Assuntos
Síndrome de Alagille , Colestase Intra-Hepática , Complicações na Gravidez , Feminino , Gravidez , Humanos , Síndrome de Alagille/complicações , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/genética , Colestase Intra-Hepática/complicações , Colestase Intra-Hepática/tratamento farmacológico , Ácido Ursodesoxicólico/uso terapêuticoRESUMO
BACKGROUND & AIMS: Alagille syndrome (ALGS) manifests with peripheral intrahepatic bile duct (IHBD) paucity, which can spontaneously resolve. In a model for ALGS, Jag1Ndr/Ndr mice, this occurs with distinct architectural mechanisms in hilar and peripheral IHBDs. Here, we investigated region-specific IHBD characteristics and addressed whether IGF1, a cholangiocyte mitogen that is downregulated in ALGS and in Jag1Ndr/Ndr mice, can improve biliary outcomes. METHODS: Intrahepatic cholangiocyte organoids (ICOs) were derived from hilar and peripheral adult Jag1+/+ and Jag1Ndr/Ndr livers (hICOs and pICOs, respectively). ICOs were grown in Matrigel or microwell arrays, and characterized using bulk RNA sequencing, immunofluorescence, and high throughput analyses of nuclear sizes. ICOs were treated with IGF1, followed by analyses of growth, proliferation, and death. CellProfiler and Python scripts were custom written for image analyses. Key results were validated in vivo by immunostaining. RESULTS: Cell growth assays and transcriptomics demonstrated that Jag1Ndr/Ndr ICOs were less proliferative than Jag1+/+ ICOs. IGF1 specifically rescued survival and growth of Jag1Ndr/Ndr pICOs. Jag1Ndr/Ndr hICOs were the least proliferative, with lower Notch signalling and an enrichment of hepatocyte signatures and IGF uptake/transport pathways. In vitro (Jag1Ndr/Ndr hICOs) and in vivo (Jag1Ndr/Ndr hilar portal tracts) analyses revealed ectopic HNF4a+ hepatocytes. CONCLUSIONS: Hilar and peripheral Jag1Ndr/Ndr ICOs exhibit differences in Notch signalling status, proliferation, and cholangiocyte commitment which may result in cholangiocyte-to-hepatocyte transdifferentiation. While Jag1Ndr/Ndr pICOs can be rescued by IGF1, hICOs are unresponsive, perhaps due to their hepatocyte-like state and/or expression of IGF transport components. IGF1 represents a potential therapeutic for peripheral bile ducts.
Assuntos
Síndrome de Alagille , Sistema Biliar , Camundongos , Animais , Síndrome de Alagille/genética , Ductos Biliares , Ductos Biliares Intra-Hepáticos , Organoides/metabolismoRESUMO
Alagille syndrome and progressive familial intrahepatic cholestasis are conditions that can affect multiple organs. Advancements in molecular testing have aided in the diagnosis of both. The impairment of normal bile flow and secretion leads to the various hepatic manifestations of these diseases. Medical management of Alagille syndrome and progressive familial intrahepatic cholestasis remains mostly targeted on supportive care focusing on quality of life, cholestasis, and fat-soluble vitamin deficiency. The most difficult therapeutic issue is typically related to pruritus, which can be managed by various medications such as ursodeoxycholic acid, rifampin, cholestyramine, and antihistamines. Surgical operations were previously used to disrupt enterohepatic recirculation, but recent medical advancements in the use of ileal bile acid transport inhibitors have shown great efficacy for the treatment of pruritus in both Alagille syndrome and progressive familial intrahepatic cholestasis.
Assuntos
Síndrome de Alagille , Colestase , Humanos , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/genética , Síndrome de Alagille/terapia , Qualidade de Vida , Prurido/diagnóstico , Prurido/cirurgiaRESUMO
Alagille syndrome (ALGS) is an autosomal dominant, multisystemic disorder due to haploinsufficiency in either the JAG1 gene (ALGS type 1) or the NOTCH2 gene (ALGS type 2). The disease has been difficult to diagnose and treat due to its muti-system clinical presentation, variable expressivity, and prenatal onset for some of the features. The generation of this iPSC line (TRNDi032-A) carrying a heterozygous mutation, p.Cys682Leufs*7 (c.2044dup), in the JAG1 gene provides a means of studying the disease and developing novel therapeutics towards patient treatment.
Assuntos
Síndrome de Alagille , Células-Tronco Pluripotentes Induzidas , Humanos , Síndrome de Alagille/genética , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Proteína Jagged-1/genética , Proteína Jagged-1/metabolismo , Mutação/genéticaRESUMO
INTRODUCTION: Alagille syndrome (ALGS) is an autosomal dominant, multisystem genetic disorder with wide phenotypic variability caused by mutations in the Notch signaling pathway, specifically from mutations in either the Jagged1 (JAG1) or NOTCH2 gene. The range of clinical features in ALGS can involve various organ systems including the liver, heart, eyes, skeleton, kidney, and vasculature. Despite the genetic mutations being well-defined, there is variable expressivity and individuals with the same mutation may have different clinical phenotypes. AREAS COVERED: While no clear genotype-phenotype correlation has been identified in ALGS, this review will summarize what is currently known about the genotype-phenotype relationship and how this relationship influences the treatment of the multisystemic disorder. This review includes discussion of numerous studies which have focused on describing the genotype-phenotype relationship of different organ systems in ALGS as well as relevant basic science and population studies of ALGS. A thorough literature search was completed via the PubMed and National Library of Medicine GeneReviews databases including dates from 1969, when ALGS was first identified, to February 2023. EXPERT OPINION: The genetics of ALGS are well defined; however, ongoing investigation to identify genotype-phenotype relationships as well as genetic modifiers as potential therapeutic targets is needed. Clinicians and patients alike would benefit from identification of a correlation to aid in diagnostic evaluation and management.
Assuntos
Síndrome de Alagille , Humanos , Síndrome de Alagille/diagnóstico , Síndrome de Alagille/genética , Síndrome de Alagille/terapia , Mutação , Fenótipo , GenótipoRESUMO
Alagille syndrome (ALGS) is a multisystem disease with high variability in clinical features. ALGS is predominantly caused by pathogenic variants in the Notch ligand JAG1. An iPSC line, NCHi011-A, was generated from a ALGS patient with complex cardiac phenotypes consisting of pulmonic valve and branch pulmonary artery stenosis. NCHi011-A is heterozygous for a single base duplication causing a frameshift in the JAG1 gene. This iPSC line demonstrates normal cellular morphology, expression of pluripotency markers, trilineage differentiation potential, and identity to the source patient. NCHi011-A provides a resource for modeling ALGS and investigating the role of Notch signaling in the disease.