Synthetic human ABCB4 mRNA therapy rescues severe liver disease phenotype in a BALB/c.Abcb4 mouse model of PFIC3

Abstract

Background & Aims: Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare lethal autosomal recessive liver disorder caused by loss-of-function variations of the ABCB4 gene, encoding a phosphatidylcholine transporter (ABCB4/MDR3). Currently, no effective treatment exists for PFIC3 outside of liver transplantation. Methods: We have produced and screened chemically and genetically modified mRNA variants encoding human ABCB4 ( hABCB4 mRNA) encapsulated in lipid nanoparticles (LNPs). We examined their pharmacological effects in a cell-based model and in a new in vivo mouse model resembling human PFIC3 as a result of homozygous disruption of the Abcb4 gene in fibrosis-susceptible BALB/c. Abcb4 −/− mice. Results: We show that treatment with liver-targeted hABCB4 mRNA resulted in de novo expression of functional hABCB4 protein and restored phospholipid transport in cultured cells and in PFIC3 mouse livers. Importantly, repeated injections of the hABCB4 mRNA effectively rescued the severe disease phenotype in young Abcb4 −/− mice, with rapid and dramatic normalisation of all clinically relevant parameters such as inflammation, ductular reaction, and liver fibrosis. Synthetic mRNA therapy also promoted favourable hepatocyte-driven liver regeneration to restore normal homeostasis, including liver weight, body weight, liver enzymes, and portal vein blood pressure. Conclusions: Our data provide strong preclinical proof-of-concept for hABCB4 mRNA therapy as a potential treatment option for patients with PFIC3.

Lipid Nanoparticle Delivery Systems to Enable mRNA-Based Therapeutics

“…Moderna took a broader approach and targeted different genetic disease models including progressive familial intrahepactic cholestasis type 3 [98], citrin deficiency [99], hemophilia A [100], acute intermittent porphyria [101], Fabry disease [102], classic galactosemia [103], alpha 1-antitrypsin deficiency [104], and arginase deficiency [105]. From the several pre-clinical studies, Moderna advanced several programs into Phase 1 studies in 2019 through 2021, based on intravenous infusion of mRNA-LNP products, including mRNA-1944 (an LNP formulation of two mRNAs encoding the heavy and light chains of a human IgG antibody directed against Chikungunya virus) [106], mRNA-3927 (an LNP formulation of two mRNAs encoding the alpha and beta subunits of the mitochondrial enzyme propionyl-CoA carboxylase, a deficiency that leads to propionic acidemia characterized by recurring life-threatening metabolic decompensations and progressive multi-organ damage) [107], and mRNA-3705 (an LNP formulation of mRNA encoding methylmalonyl-CoA mutase, in which a deficiency leads to methylmalonic acidemia, a progressive and highly lethal disease characterized by episodes of metabolic decompensation) [108].…”

Genetic Analysis of ABCB4 Mutations and Variants Related to the Pathogenesis and Pathophysiology of Low Phospholipid-Associated Cholelithiasis

“…More recently, a new method with genetically modified mRNA variants encoding human ABCB4 ( hABCB4 mRNA) encapsulated in lipid nanoparticles for gene therapy of dysfunctional ABCB4 has been developed in a BALB/c.Abcb4 KO mouse model of PFIC3 [ 172 ]. The results from the study with this mouse model have provided clear evidence that treatment with liver-targeted hABCB4 mRNA leads to the expression of functional hABCB4 protein in the liver, thereby restoring hepatic phospholipid secretion into bile in the mouse model of PFIC3.…”

Novel vectors and approaches for gene therapy in liver diseases

“…These nanoparticles have been shown to deliver mRNA molecules to hepatocytes with high efficiency, correcting mouse models of genetic diseases such as methylmalonic acidemia (MMA), PH1, GSD1a, citrin deficiency, acute intermittent porphyria (AIP), maple syrup urine disease, arginase deficiency, OTC deficiency, and progressive familial cholestasis type 3 (PFIC3). [53] , [54] , [55] , [56] , [57] , [58] , [59] The duration of action of a single dose of mRNA-LNP lasted between 2–3 weeks, requiring repeat administration to prolong a curative effect. These encouraging results supported the initiation of a phase I/II trial for the treatment of MMA ( Table 1 ).…”