Related Experiment Video
Updated: Jun 4, 2026
A Mouse Model of Chronic Liver Fibrosis for the Study of Biliary Atresia
Published on: February 3, 2023
A mouse model of β-thalassemia shows a liver-specific down-regulation of Abcc6 expression
Ludovic Martin1, Vanessa Douet, Christopher M VanWart
1Department of Dermatology, University Hospital of Angers, Angers, France.
Insights
Beta-thalassemia patients exhibit pseudoxanthoma elasticum-like mineralization due to decreased ABCC6 gene expression in the liver. This suggests a shared pathway for these distinct genetic disorders.
Area of Science:
- Genetics
- Molecular Biology
- Biochemistry
Background:
- Beta-thalassemia and pseudoxanthoma elasticum (PXE) are distinct genetic disorders.
- PXE-like calcification is observed in beta-thalassemia patients, despite lacking PXE-causing mutations.
Purpose of the Study:
- To investigate the molecular mechanism behind PXE-like manifestations in beta-thalassemia.
- To examine ABCC6 gene expression and regulation in a beta-thalassemia mouse model.
Main Methods:
- Quantitative PCR and Western blotting to assess Abcc6 gene and protein levels.
- Immunofluorescence to localize Abcc6 protein.
- Transcription factor arrays and chromatin immunoprecipitation to study gene regulation.
Main Results:
- Progressive, liver-specific down-regulation of Abcc6 gene expression and protein levels in beta-thalassemia mice.
- Abcc6 protein levels decreased to approximately 25% of wild-type levels by 10 months of age.
- The erythroid transcription factor NF-E2 was identified as a key factor in Abcc6 transcriptional down-regulation.
Conclusions:
- Reduced ABCC6 expression in the liver of beta-thalassemia patients may cause PXE-like manifestations.
- This finding suggests a potential link between beta-thalassemia and PXE pathogenesis through altered ABCC6 regulation.
Abstract:
β-Thalassemia and pseudoxanthoma elasticum (PXE) are distinct genetic disorders. Yet, a dystrophic mineralization phenotype similar to PXE has frequently been associated with β-thalassemia or sickle cell anemia patients of Mediterranean descent. These calcifications are clinically and structurally identical to inherited PXE. As we previously excluded the presence of PXE-causing mutations in the ABCC6 gene of β-thalassemia patients with PXE manifestations, we hypothesized that a molecular mechanism independent of gene mutations either altered the ABCC6 gene expression or disrupted the biologic properties of its product in the liver or kidneys, which are the tissues with the highest levels of expression. To test this possibility, we investigated Abcc6 synthesis in the liver and kidneys of a β-thalassemia mouse model (Hbb(th3/+)). We found a progressive liver-specific down-regulation of the Abcc6 gene expression and protein levels by quantitative PCR, Western blotting, and immunofluorescence. The levels of Abcc6 protein decreased significantly at 6 months of age and stabilized at 10 months and older ages at ∼25% of the wild-type protein levels. We studied the transcriptional regulation of the Abcc6 gene in wild-type and Hbb(th3/+) mice, and we identified the erythroid transcription factor NF-E2 as the main cause of the transcriptional down-regulation using transcription factor arrays and chromatin immunoprecipitation. The Hbb(th3/+) mice did not develop spontaneous calcification as seen in the Abcc6(-/-) mice probably because the Abcc6 protein decrease occurred late in life and was probably insufficient to promote mineralization in the Hbb(th3/+) mouse C57BL/6J genetic background. Nevertheless, our result suggested that a similar decrease of ABCC6 expression occurs in the liver of β-thalassemia patients and may be responsible for their frequent PXE-like manifestations.
