Reversal of gene expression profile in the phenylketonuria mouse model after adeno-associated virus vector-mediated gene therapy Hyun-Jeong Oh a,b , Hyejin Lee a , Joo-Won Park c , Hwanseok Rhee d , Soo Kyung Koo a , Seongman Kang b , Inho Jo a , Sung-Chul Jung c, * a Department of Biomedical Sciences, National Institute of Health, Seoul 122-701, Republic of Korea b Graduate School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea c Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul 158-710, Republic of Korea d Department of Clinical Genetics, Yonsei University College of Medicine, Seoul 150-752, Republic of Korea Received 19 May 2005; received in revised form 21 June 2005; accepted 24 June 2005 Available online 16 September 2005 Abstract Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by phenylalanine hydroxylase (PAH) deficiency. Accumulation of phenylalanine leads to severe mental and psychomotor retardation, and hypopigmentation of skin and hair. We have demonstrated the cognitive outcome of biochemical and phenotypic reversal by the adeno-associated virus vector-mediated gene delivery of a human PAH transgene. In this study, we identified the expression of genes related to pathologic abnormalities of the PKU-affected brain, in which the symptoms of PKU are mainly manifest, and transcriptional changes in effective gene therapy treatment using oligonucleotide array. Therapeutic effectiveness was verified by change in enzyme activity (15 ± 5.84%), phenylal- anine plasma level (261 ± 108 lM), and coat color. Our data indicated that 12 genes were significantly up-regulated in PKU. Four are involved in defense and inflammatory responses of neutrophils (NE, MPO, NGP, and CRAMP), three other overexpressed genes are related to extracellular matrix organization and degradation (COL1A1, COL1A2, and MMP13); the remainder were a nociceptor in sensory neurons (MrgA1), a structural gene of P lysozyme (Lzp-s), an immunoglobulin a heavy chain constant region gene (Igh-2), an osteocalcin-related protein precursor (Bglap-rs1), and a membrane-spanning 4 domain, subfamily A, member 3 (Ms4a3). Data demonstrated that elevated genes in the PKU-affected brain could be normalized by human PAH gene delivery. Although we could not precisely link transcript level changes and neurologic pathogenesis, this study provides a more comprehen- sive understanding of the PKU-affected brain at the molecular level, possibly resulting in better therapeutic approaches. Ó 2005 Elsevier Inc. All rights reserved. Keywords: Phenylketonuria; Mouse; Gene therapy; Adeno-associated virus; Microarray; Neurological pathogenesis Introduction Phenylketonuria (PKU) (MIM 261600) is an inherit- ed metabolic disorder caused by various mutations in the hepatic enzyme phenylalanine hydroxylase (PAH) gene, and is characterized by the impaired phenylalanine metabolism due to the lack of phenylalanine hydroxy- lase, which converts the essential amino acid phenylala- nine into tyrosine using tetrahydrobiopterin (BH 4 ) as a cofactor [1–3]. The dysfunction of this enzyme in the liv- er contributes to the accumulation of phenylalanine and its abnormal metabolites in the blood and other tissues. Abnormally high levels of phenylalanine in blood and brain cause a variety of complications, including hypo- pigmentation of skin, hair, and eyes, growth failure, www.elsevier.com/locate/ymgme Molecular Genetics and Metabolism 86 (2005) S124–S132 1096-7192/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.ymgme.2005.06.015 * Corresponding author. Fax: +82 2 6008 7850. E-mail address: jungsc@ewha.ac.kr (S.-C. Jung).