Systemic modified messenger RNA for replacement therapy in alpha 1-antitrypsin deficiency

Eleonora Guadagnin,Andrea L. Frassetto,Helen Zemack,Lisa M. Rice,Rebecca A. White,Greg Nowak,Alex G. Cavedon,Ahmad Karadagi,Xuling Zhu,Paolo G. V. Martini,Ewa Ellis,Marianne E. Eybye,Carl Jorns,Stephen Strom

doi:10.1038/s41598-020-64017-0

Abstract

Alpha 1-antitrypsin (AAT) deficiency arises from an inherited mutation in the SERPINA1 gene. The disease causes damage in the liver where the majority of the AAT protein is produced. Lack of functioning circulating AAT protein also causes uninhibited elastolytic activity in the lungs leading to AAT deficiency-related emphysema. The only therapy apart from liver transplantation is augmentation with human AAT protein pooled from sera, which is only reserved for patients with advanced lung disease caused by severe AAT deficiency. We tested modified mRNA encoding human AAT in primary human hepatocytes in culture, including hepatocytes from AAT deficient patients. Both expression and functional activity were investigated. Secreted AAT protein increased from 1,14 to 3,43 µg/ml in media from primary human hepatocytes following mRNA treatment as investigated by ELISA and western blot. The translated protein showed activity and protease inhibitory function as measured by elastase activity assay. Also, mRNA formulation in lipid nanoparticles was assessed for systemic delivery in both wild type mice and the NSG-PiZ transgenic mouse model of AAT deficiency. Systemic intravenous delivery of modified mRNA led to hepatic uptake and translation into a functioning protein in mice. These data support the use of systemic mRNA therapy as a potential treatment for AAT deficiency.

Highlights

Alpha 1-antitrypsin deficiency (AATD) is an underdiagnosed autosomal recessive disease primarily affecting the lungs and the liver
Given that modified messenger RNA (mRNA) has been demonstrated to be useful in several areas and in vivo delivery is feasible, we explored its application targeting human hepatocytes and investigated AAT encoding modified mRNA on primary human hepatocytes
Manifested liver cirrhosis with or without hepatocellular carcinoma is treated with liver transplantation, transplantation is limited by organ shortage making this therapy scarce and not available for all patients in need

Summary

Introduction

Alpha 1-antitrypsin deficiency (AATD) is an underdiagnosed autosomal recessive disease primarily affecting the lungs and the liver. Laurell and Eriksson first described the condition based on observations of electrophoresis of sera from patients in 1963 in Sweden[1] It is often misdiagnosed as chronic obstructive lung disease. Modified mRNA has several advantages over conventional gene therapy approaches of virus- and DNA-based vectors, avoiding risk of tumorigenicity, suboptimal genome integration, ectopic sustained expression, and disadvantages related to development and production[19,20,21]. This emerging technology has been suggested for application in enzyme replacement therapies and is of particular interest for inborn errors of metabolism[22]

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