Gene therapy for progressive familial intrahepatic cholestasis type 3 in a clinically relevant mouse model

Nicholas D Weber,Cristian Smerdou,Anne Douar,Gloria González-Aseguinolaza,Bernard Bénichou,Javier Martínez-García,Veronica Ferrer,Leticia Odriozola

doi:10.1038/s41467-019-13614-3

Abstract

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare monogenic disease caused by mutations in the ABCB4 gene, resulting in a reduction in biliary phosphatidylcholine. Reduced biliary phosphatidylcholine cannot counteract the detergent effects of bile salts, leading to cholestasis, cholangitis, cirrhosis and ultimately liver failure. Here, we report results from treating two- or five-week-old Abcb4−/− mice with an AAV vector expressing human ABCB4, resulting in significant decreases of PFIC3 disease biomarkers. All male mice achieved a sustained therapeutic effect up through 12 weeks, but the effect was achieved in only 50% of females. However, two-week-old females receiving a second inoculation three weeks later maintained the therapeutic effect. Upon sacrifice, markers of PFIC3 disease such as, hepatosplenomegaly, biliary phosphatidylcholine and liver histology were significantly improved. Thus, AAV-mediated gene therapy successfully prevented PFIC3 symptoms in a clinically relevant mouse model, representing a step forward in improving potential therapy options for PFIC3 patients.

Highlights

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare monogenic disease caused by mutations in the ABCB4 gene, resulting in a reduction in biliary phosphatidylcholine
In the case of PFIC type 3 (PFIC3, or MDR3 deficiency associated with PFIC), mutations affect the ABCB4 gene, which encodes for multidrug resistance protein 3 (MDR3), a floppase involved in the translocation of phosphatidylcholine (PC) from the hepatocyte membrane to the bile
A mouse model for PFIC3 in which the Abcb[4] gene was disrupted by elimination of its two first exons has been described[9]. These mice completely lack expression of MDR2, and are unable to secrete PC to the bile. This results in symptoms that reproduce most of the biomarkers and pathological signs of human PFIC3, including hepatosplenomegaly and liver fibrosis, the severity and progression of the disease varies depending on the mouse strain[10]

Summary

Introduction

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare monogenic disease caused by mutations in the ABCB4 gene, resulting in a reduction in biliary phosphatidylcholine. We have developed a therapeutic strategy for PFIC3 based on the administration of an AAV8 vector designed for liver-specific human MDR3 expression in a strain of Abcb4−/− mice that spontaneously progress to severe biliary fibrosis[11]. This therapy was able to increase biliary PC levels, resulting in normalization of all serum biomarkers, complete prevention of liver fibrosis and long-term correction of the disease in treated mice

Methods

Results

Conclusion