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Iino K, Toriumi K, Agarie R, Miyashita M, Suzuki K, Horiuchi Y, Niizato K, Oshima K, Imai A, Nagase Y, Kushima I, Koike S, Ikegame T, Jinde S, Nagata E, Washizuka S, Miyata T, Takizawa S, Hashimoto R, Kasai K, Ozaki N, Itokawa M, Arai M. AKR1A1 Variant Associated With Schizophrenia Causes Exon Skipping, Leading to Loss of Enzymatic Activity. Front Genet 2021; 12:762999. [PMID: 34938315 PMCID: PMC8685500 DOI: 10.3389/fgene.2021.762999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/10/2021] [Indexed: 11/23/2022] Open
Abstract
Schizophrenia is a heterogeneous psychiatric disorder characterized by positive symptoms such as hallucinations and delusions, negative symptoms such as anhedonia and flat affect, and cognitive impairment. Recently, glucuronate (GlucA) levels were reported to be significantly higher in serum of patients with schizophrenia than those in healthy controls. The accumulation of GlucA is known to be related to treatment-resistant schizophrenia, since GlucA is known to promote drug excretion by forming conjugates with drugs. However, the cause of GlucA accumulation remains unclear. Aldo-keto reductase family one member A1 (AKR1A1) is an oxidoreductase that catalyzes the reduction of GlucA. Genetic loss of AKR1A1 function is known to result in the accumulation of GlucA in rodents. Here, we aimed to explore genetic defects in AKR1A1 in patients with schizophrenia, which may result in the accumulation of GlucA. We identified 28 variants of AKR1A1 in patients with schizophrenia and control subjects. In particular, we identified a silent c.753G > A (rs745484618, p. Arg251Arg) variant located at the first position of exon 8 to be associated with schizophrenia. Using a minigene assay, we found that the c.753G > A variant induced exon 8 skipping in AKR1A1, resulting in a frameshift mutation, which in turn led to truncation of the AKR1A1 protein. Using the recombinant protein, we demonstrated that the truncated AKR1A1 completely lost its activity. Furthermore, we showed that AKR1A1 mRNA expression in the whole blood cells of individuals with the c.753G > A variant tended to be lower than that in those without the variants, leading to lower AKR activity. Our findings suggest that AKR1A1 carrying the c.753G > A variant induces exon skipping, leading to a loss of gene expression and enzymatic activity. Thus, GlucA patients with schizophrenia with the c.753G > A variant may show higher GlucA levels, leading to drug-resistant schizophrenia, since drug excretion by GlucA is enhanced.
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Affiliation(s)
- Kyoka Iino
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuya Toriumi
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Riko Agarie
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mitsuhiro Miyashita
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, Tokyo, Japan
- Department of Psychiatry, Takatsuki Hospital, Hachioji, Tokyo, Japan
| | - Kazuhiro Suzuki
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- Department of Psychiatry, Graduate School of Medicine, Shinshu University, Nagano, Japan
| | - Yasue Horiuchi
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiro Niizato
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, Tokyo, Japan
| | - Kenichi Oshima
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, Tokyo, Japan
| | - Atsushi Imai
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, Tokyo, Japan
| | - Yukihiro Nagase
- Department of Psychiatry, Takatsuki Hospital, Hachioji, Tokyo, Japan
| | - Itaru Kushima
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Medical Genomics Center, Nagoya University Hospital, Nagoya, Japan
| | - Shinsuke Koike
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tempei Ikegame
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Seiichiro Jinde
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Eiichiro Nagata
- Department of Neurology, Tokai University School of Medicine, Isehara, Japan
| | - Shinsuke Washizuka
- Department of Psychiatry, Graduate School of Medicine, Shinshu University, Nagano, Japan
| | - Toshio Miyata
- Division of Molecular Medicine and Therapy, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Shunya Takizawa
- Department of Neurology, Tokai University School of Medicine, Isehara, Japan
| | - Ryota Hashimoto
- Department of Pathology of Mental Diseases, National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Kiyoto Kasai
- Department of Neuropsychiatry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- The International Research Center for Neurointelligence (WPI-IRCN) at The University of Tokyo Institutes for Advanced Study (UTIAS), Aoba-ku, Sendai, Japan
| | - Norio Ozaki
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masanari Itokawa
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, Tokyo, Japan
| | - Makoto Arai
- Schizophrenia Research Project, Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- *Correspondence: Makoto Arai,
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Kawamura M, Eisenhofer G, Kopin IJ, Kador PF, Lee YS, Fujisawa S, Sato S. Aldose reductase: an aldehyde scavenging enzyme in the intraneuronal metabolism of norepinephrine in human sympathetic ganglia. Auton Neurosci 2002; 96:131-9. [PMID: 11958479 DOI: 10.1016/s1566-0702(01)00385-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The neurotransmitter norepinephrine is metabolized by monoamine oxidase into an aldehyde intermediate that is further metabolized to the stable glycol derivative, 3,4-dihydroxyphenylglycol (DHPG). In this study, the possible role of aldose reductase in reducing this aldehyde intermediate in human sympathetic neurons has been examined. DHPG is formed when norepinephrine is incubated with aldose reductase in the presence of monoamine oxidase. DHPG metabolism is inhibited by the monoamine oxidase inhibitor, pargyline which prevents the deamination of norepinephrine, and by the aldose reductase inhibitor AL 1576, which inhibits DHPG formation without affecting the deamination of norepinephrine. Although similar formation of DHPG was observed with human liver aldehyde reductase, the production of DHPG was more effective with aldose reductase than aldehyde reductase. Two peaks of reductase activity corresponding to aldose reductase and aldehyde reductase were observed when sympathetic ganglia were chromatofocused. Molecular modeling studies indicate that the energy-minimized structure of 3,4-dihydroxymandelaldehyde bound to aldose reductase is similar to that of glyceraldehyde where the 2'-hydroxyl group forms hydrogen bonds with Trp111 and NADPH. These results suggest that aldose reductase may be important in metabolizing the potentially toxic aldehyde intermediate formed from norepinephrine in human sympathetic ganglia.
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Affiliation(s)
- Minoru Kawamura
- Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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