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Author Notes:

Judith L. Fridovich‐Keil, Department of Human Genetics, Emory University School of Medicine, Room 325.2 Whitehead Building, 615 Michael Street, Atlanta, GA 30322, USA. Email: jfridov@emory.edu

Jenna Daenzer helped to design and interpret experiments, performed or oversaw the majority of biochemical and metabolic work reported, and participated in writing and editing of the manuscript. Shauna Rasmussen helped to design and interpret experiments, performed or oversaw the majority of animal work reported, and participated in writing and editing of the manuscript. Sneh Patel quantified IHC staining, performed all statistical analyses, and participated in writing and editing of the manuscript. James McKenna performed much of the IF work and participated in editing of the manuscript. Judith Fridovich‐Keil oversaw the design and interpretation of all experiments, coordinated the activities of all co‐authors, helped with some of the animal work, and did most of the writing and editing of the manuscript.

We are grateful to numerous colleagues for their contributions to this project. We specifically thank Dr. Uriel Blas‐Machado, of the University of Georgia, for reviewing our histology slides, and Dr. Lyra Griffiths, of the Emory Integrated Cores, for performing the quantitative PCR required to calculate viral genome copy number in tissue samples. We also thank all members of the Fridovich‐Keil lab for constant support, and the many professionals working in the Emory Division of Animal Resources and the Emory IACUC without whom this work could not have been conducted.

The authors declare no conflicts of interest.

Subject:

Research Funding:

This work was supported in part by grants from the National Institutes of Health R01DK107900 and R21HD092785 (both to JLFK), and in part by the Emory Integrated Genomics Core (EIGC), which is subsidized by the Emory University School of Medicine and is one of the Emory Integrated Core Facilities.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Endocrinology & Metabolism
  • Genetics & Heredity
  • Medicine, Research & Experimental
  • Research & Experimental Medicine
  • AAV9
  • galactosemia
  • GALT
  • gene therapy
  • metabolite
  • rat
  • scAAV9
  • PROTEIN
  • PYROPHOSPHORYLASE
  • MANAGEMENT
  • EXPRESSION

Neonatal GALT gene replacement offers metabolic and phenotypic correction through early adulthood in a rat model of classic galactosemia

Journal Title:

JOURNAL OF INHERITED METABOLIC DISEASE

Volume:

Volume 45, Number 2

Publisher:

, Pages 203-214

Type of Work:

Article | Final Publisher PDF

Abstract:

Classic galactosemia (CG) results from profound deficiency of galactose-1-P uridylyltransferase (GALT). Despite early detection by newborn screening and lifelong dietary restriction of galactose, most patients grow to experience a range of long-term complications. Recently, we developed and characterized a GALT-null rat model of CG and demonstrated that AAV9-hGALT, administered by tail vein injection to neonatal pups, dramatically improved plasma, liver, and brain galactose metabolites at 2 weeks posttreatment. Here we report a time-course study of GALT restoration in rats treated as neonates with scAAV9-hGALT and harvested at 8, 14, 30, and 60 days. Cohorts of rats in the two older groups were weaned to diets containing either 1% or 3% of calories from galactose. As expected, GALT activity in all treated animals peaked early and then diminished over time, most notably in liver, ostensibly due to dilution of the nonreplicating episomal vector as transduced cells divided. All treated rats showed dramatic metabolic rescue through 1 month, and those weaned to the lower galactose diet showed continued strong metabolic rescue into adulthood (2 months). Prepubertal growth delay and cataracts were both partially rescued by treatment. Finally, we found that UDP glucose pyrophosphorylase (UGP), which offers a metabolic bypass around missing GALT, was 3-fold more active in brain samples from adult rats than from young pups, offering a possible explanation for the improved ability of older GALT-null rats to metabolize galactose. Combined, these results document promising metabolic and phenotypic efficacy of neonatal GALT gene replacement in a rat model of classic galactosemia.

Copyright information:

© 2021 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (https://creativecommons.org/licenses/by-nc-nd/4.0/).
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