Contribution of Brain Intrinsic Branched-Chain Amino Acid Metabolism in a Novel Mouse Model of Maple Syrup Urine Disease

IF 4.2 2区 医学 Q1 ENDOCRINOLOGY & METABOLISM
Amanda C. Kuhs, Laura Ohl, Tegan Thurston, Jeet Singh, Sangeetha Bhuyan, Sarah Grandinette, Jing Xu, Sophie A. Siemsgluess, Youseff Jakher, Rebecca C. Ahrens-Nicklas
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引用次数: 0

Abstract

Maple syrup urine disease (MSUD) results from loss of branched-chain ketoacid dehydrogenase (BCKDH) activity, the committed, rate-limiting step of branched-chain amino acid (BCAA) oxidation. Current treatments, including a low protein diet and liver transplantation, improve peripheral biochemistry and limit episodes of metabolic decompensation but do not fully prevent chronic neuropsychiatric symptoms. The mechanisms underlying chronic neurologic phenotypes remain poorly understood. Currently available MSUD mouse models do not survive long enough to evaluate chronic central nervous system (CNS) pathology. To investigate if loss of brain-intrinsic BCAA metabolism contributes to chronic neurologic disease, we developed a new brain-specific knockout mouse model of MSUD. First, we generated a mouse harboring a floxed Dbt allele (Dbtflox/flox). Then we crossed this line with Cre recombinase driver lines to induce loss of Dbt expression in (1) all developing CNS cell populations (2) neurons alone or (3) astrocytes alone. We found that brain-specific KO mice have elevations in BCAA levels in cortex that are exacerbated by a high protein diet. They also have secondary changes in amino acids in brain that are important for neuronal function, including glutamine and glycine. These metabolic differences result in subtle functional deficits as measured by electroencephalogram and behavioral testing. Astrocyte and neuron-specific KO mice each also demonstrate mild biochemical features of MSUD in the cortex, suggesting that both cell populations may contribute to disease pathology. Collectively, these data suggest that therapies targeting the CNS directly, in addition to the periphery, may improve outcomes in MSUD.

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来源期刊
Journal of Inherited Metabolic Disease
Journal of Inherited Metabolic Disease 医学-内分泌学与代谢
CiteScore
9.50
自引率
7.10%
发文量
117
审稿时长
4-8 weeks
期刊介绍: The Journal of Inherited Metabolic Disease (JIMD) is the official journal of the Society for the Study of Inborn Errors of Metabolism (SSIEM). By enhancing communication between workers in the field throughout the world, the JIMD aims to improve the management and understanding of inherited metabolic disorders. It publishes results of original research and new or important observations pertaining to any aspect of inherited metabolic disease in humans and higher animals. This includes clinical (medical, dental and veterinary), biochemical, genetic (including cytogenetic, molecular and population genetic), experimental (including cell biological), methodological, theoretical, epidemiological, ethical and counselling aspects. The JIMD also reviews important new developments or controversial issues relating to metabolic disorders and publishes reviews and short reports arising from the Society''s annual symposia. A distinction is made between peer-reviewed scientific material that is selected because of its significance for other professionals in the field and non-peer- reviewed material that aims to be important, controversial, interesting or entertaining (“Extras”).
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