Localization of sepiapterin reductase in the human brain

Keiko Ikemoto, Takahiro Suzuki, Hiroshi Ichinose, Tamae Ohye, Akiyoshi Nishimura, Katsuji Nishi, Ikuko Nagatsu, Toshiharu Nagatsu

Research output: Contribution to journalArticle

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Abstract

Sepiapterin reductase (SPR) is the enzyme that catalyzes the final step of the synthesis of tetrahydrobiopterin (BH4), the cofactor for phenylalanine hydroxylase, tyrosine hydroxylase (TH), tryptophan hydroxylase, and nitric oxide synthase (NOS). Although SPR is essential for synthesizing BH4, the distribution of SPR in the human brain has not yet been clarified. In the present study, we purified recombinant human SPR from cDNA, raised an antibody against human SPR (hSPR), and examined the localization of SPR protein and SPR activity. Human brain homogenates from the substantia nigra (SN), caudate nucleus (CN), gray and white matters of the cerebral cortex (CTX), and dorsal and ventral parts of the medulla oblongata (MO) were subjected to Western blot analysis with anti-hSPR antibody or with anti-TH antibody. Whereas TH protein showed a restricted localization, being mainly detected in the SN and CN, SPR protein was detected in all brain regions examined. SPR activity was relatively high compared with the activity of GTP cyclohydrolase I (GCH), the rate-limiting biosynthetic enzyme of BH4, and was more widely distributed than GCH activity. Immunohistochemistry revealed SPR immunoreactivity in pyramidal neurons in the cerebral CTX, in a small number of striatal neurons, and in neurons of the hypothalamic and brain stem monoaminergic fields and olivary nucleus. Double-staining immunohistochemistry showed that TH and SPR were colocalized in the SN dopamine neurons. Localization of SPR immunoreactive neurons corresponded to monoamine or NOS neuronal fields, and also to the areas where no monoamine or NOS neurons were located. The results indicate that there might be a BH4 biosynthetic pathway where GCH is not involved and that SPR might have some yet unidentified function(s) in addition to BH4 biosynthesis.

Original languageEnglish
Pages (from-to)237-246
Number of pages10
JournalBrain Research
Volume954
Issue number2
DOIs
Publication statusPublished - 08-11-2002

Fingerprint

sepiapterin reductase
Brain
GTP Cyclohydrolase
Tyrosine 3-Monooxygenase
Substantia Nigra
Neurons
Caudate Nucleus
Nitric Oxide Synthase
Cerebral Cortex
Antibodies
Immunohistochemistry
Olivary Nucleus

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

Cite this

Ikemoto, K., Suzuki, T., Ichinose, H., Ohye, T., Nishimura, A., Nishi, K., ... Nagatsu, T. (2002). Localization of sepiapterin reductase in the human brain. Brain Research, 954(2), 237-246. https://doi.org/10.1016/S0006-8993(02)03341-3
Ikemoto, Keiko ; Suzuki, Takahiro ; Ichinose, Hiroshi ; Ohye, Tamae ; Nishimura, Akiyoshi ; Nishi, Katsuji ; Nagatsu, Ikuko ; Nagatsu, Toshiharu. / Localization of sepiapterin reductase in the human brain. In: Brain Research. 2002 ; Vol. 954, No. 2. pp. 237-246.
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Ikemoto, K, Suzuki, T, Ichinose, H, Ohye, T, Nishimura, A, Nishi, K, Nagatsu, I & Nagatsu, T 2002, 'Localization of sepiapterin reductase in the human brain', Brain Research, vol. 954, no. 2, pp. 237-246. https://doi.org/10.1016/S0006-8993(02)03341-3

Localization of sepiapterin reductase in the human brain. / Ikemoto, Keiko; Suzuki, Takahiro; Ichinose, Hiroshi; Ohye, Tamae; Nishimura, Akiyoshi; Nishi, Katsuji; Nagatsu, Ikuko; Nagatsu, Toshiharu.

In: Brain Research, Vol. 954, No. 2, 08.11.2002, p. 237-246.

Research output: Contribution to journalArticle

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T1 - Localization of sepiapterin reductase in the human brain

AU - Ikemoto, Keiko

AU - Suzuki, Takahiro

AU - Ichinose, Hiroshi

AU - Ohye, Tamae

AU - Nishimura, Akiyoshi

AU - Nishi, Katsuji

AU - Nagatsu, Ikuko

AU - Nagatsu, Toshiharu

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Y1 - 2002/11/8

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Ikemoto K, Suzuki T, Ichinose H, Ohye T, Nishimura A, Nishi K et al. Localization of sepiapterin reductase in the human brain. Brain Research. 2002 Nov 8;954(2):237-246. https://doi.org/10.1016/S0006-8993(02)03341-3