Differential tissue distribution of tryptophan hydroxylase isoforms 1 and 2 as revealed with monospecific antibodies

Sakowski, Stacey A.; Geddes, Timothy J.; Thomas, David M.; Levi, Edi; Hatfield, James S.; Kuhn, Donald M.

doi:10.1016/j.brainres.2006.02.047

Cited by 133 publications

(104 citation statements)

References 39 publications

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“…Quantitative PCR revealed a 1 : 1.2 ratio (normalized to PolR2A expression levels) of TPH1 compared with TPH2 mRNA expression in undifferentiated ANSC (Figure 2b). Finally, by using polyclonal rabbit anti-mouse antibodies specific for each TPH isoform (Sakowski et al, 2006) we confirmed PCR results, showing that both TPH1 and TPH2 proteins are present in undifferentiated ANSC (Figure 2c). The presence of 5-HT and its metabolite 5HIAA in supernatants of cultured ANSC was confirmed by means of HPLC analysis (Figure 3).…”

Section: Ansc Express Tryptophan Hydroxylase 1 and 2 And Produce 5-htsupporting

confidence: 75%

“…In these cell cultures we evaluated the proportions of different neural cell types (neurons, astrocytes, and oligodendrocytes). Primary antibodies were: polyclonal sheep anti-TPH (1 : 100, AB1541, Chemicon), rabbit anti-GFAP (1 : 300, Chemicon), monoclonal anti-TUJ1 (1 : 1000, Covance), anti-GalCer (1 : 100, Chemicon), polyclonal rabbit anti-TPH1 and rabbit anti-TPH2 (1 : 400; both kind gifts from Donald M Kuhn, Department of Psychiatry, Wayne State University (Sakowski et al, 2006)). …”

Section: Differentiation Of Stem Cell Progeny Immunocytochemistry Fmentioning

confidence: 99%

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Serotonin Depletion Hampers Survival and Proliferation in Neurospheres Derived from Adult Neural Stem Cells

Benninghoff¹,

Gritti²,

Rizzi³

et al. 2009

Neuropsychopharmacol

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Serotonin (5-HT) and the serotonergic system have recently been indicated as modulators of adult hippocampal neurogenesis. In this study, we evaluated the role of 5-HT on the functional features in neurospheres derived from adult neural stem cells (ANSC). We cultured neurospheres derived from mouse hippocampus in serum-free medium containing epidermal (EGF) and type-2 fibroblast growth factor (FGF2). Under these conditions ANSC expressed both isoforms of tryptophane-hydroxylase (TPH) and produced 5-HT. Blocking TPH function by para-chlorophenylalanine (PCPA) reduced ANSC proliferation, which was rescued by exogenous 5-HT. 5-HT action on ANSC was mediated predominantly by the serotonin receptor subtype 5-HT1A and, to a lesser extent, through the 5-HT2C (receptor) subtype, as shown by selectively antagonizing these receptors. Finally, we documented a 5-HT-induced increase of ANSC migration activity. In summary, we demonstrated a powerful serotonergic impact on ANSC functional features, which was mainly mediated by 5-HT1A receptors.

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Section: Ansc Express Tryptophan Hydroxylase 1 and 2 And Produce 5-htsupporting

confidence: 75%

Section: Differentiation Of Stem Cell Progeny Immunocytochemistry Fmentioning

confidence: 99%

Serotonin Depletion Hampers Survival and Proliferation in Neurospheres Derived from Adult Neural Stem Cells

Benninghoff¹,

Gritti²,

Rizzi³

et al. 2009

Neuropsychopharmacol

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“…It is possible that the difference in the size of the human and murine TPH2 proteins is due to differences in post-translational modifications made in different cell types or tissues from different species. With regard to the doublet detected in some human CNS samples, Sakowski et al 34 have generated a TPH2-specific antiserum to an overlapping region of the TPH2 sequence and have reported the detection of a similar doublet, when immunoblotting protein extracts from certain rodent CNS tissues. Further study is required …”

Section: Discussionmentioning

confidence: 99%

“…The TPH2-specific antiserum (aTPH2) detected proteins of approximately 55 kDa in murine mesencephalic tegmental, striatal and hippocampal samples. 34 No TPH2 protein was detected in the pineal gland with aTPH2 by immunoblot. These findings stand in contrast to our data, which show fiber and cell body staining with TPH2-6361 in rodent and human pineal gland.…”

Section: Pitmentioning

confidence: 95%

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Glucocorticoid modulation of tryptophan hydroxylase-2 protein in raphe nuclei and 5-hydroxytryptophan concentrations in frontal cortex of C57/Bl6 mice

et al. 2007

Mol Psychiatry

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Considerable attention has focused on regulation of central tryptophan hydroxylase (TPH) activity and protein expression. At the time of these earlier studies, it was thought that there was a single central TPH isoform. However, with the recent identification of TPH2, it becomes important to distinguish between regulatory effects on the protein expression and activity of the two isoforms. We have generated a TPH2-specific polyclonal antiserum (TPH2-6361) to study regulation of TPH2 at the protein level and to examine the distribution of TPH2 expression in rodent and human brain. TPH2 immunoreactivity (IR) was detected throughout the raphe nuclei, in lateral hypothalamic nuclei and in the pineal body of rodent and human brain. In addition, a prominent TPH2-IR fiber network was found in the human median eminence. We recently reported that glucocorticoid treatment of C57/Bl6 mice for 4 days markedly decreased TPH2 messenger RNA levels in the raphe nuclei, whereas TPH1 mRNA was unaffected. The glucocorticoid-elicited inhibition of TPH2 gene expression was blocked by co-administration of the glucocorticoid receptor antagonist mifepristone (RU-486). Using TPH2-6361, we have extended these findings to show a dose-dependent decrease in raphe TPH2 protein levels in response to 4 days of treatment with dexamethasone; this effect was blocked by co-administration of mifepristone. Moreover, the glucocorticoid-elicited inhibition of TPH2 was functionally significant: serotonin synthesis was significantly reduced in the frontal cortex of glucocorticoid-treated mice, an effect that was blocked by mifepristone coadministration. This study provides further evidence for the glucocorticoid regulation of serotonin biosynthesis via inhibition of TPH2 expression, and suggest that elevated glucocorticoid levels may be relevant to the etiology of psychiatric diseases, such as depression, where hypothalamic-pituitary-adrenal axis dysregulation has been documented.

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Association of Functional Polymorphisms of the Human Tryptophan Hydroxylase 2 Gene With Risk for Bipolar Disorder in Han Chinese

Lin¹,

Chao²,

Chen³

et al. 2007

Arch Gen Psychiatry

115

107

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Context:The tryptophan hydroxylase 2 (TPH2) gene encodes the first (also the rate-limiting) enzyme in the serotonin biosynthetic pathway. Despite reports of possible associations between polymorphisms in human TPH2 and many psychiatric disorders, including bipolar disorder (BPD), the functional effect and susceptibility loci of such polymorphisms for BPD have not yet been identified. Objectives:To examine the association of TPH2 with BPD and to identify the functional variants that may be involved in the pathophysiological development of BPD.Design, Setting, and Patients: We systematically screened all exons and promoters of the TPH2 gene in Han Chinese subjects to identify sequence variants. Association tests were conducted in 105 cases and 106 control subjects using single-locus, linkage disequilibrium, and haplotype analyses. Two promoter and one exon 2 single-nucleotide polymorphisms were examined for their functional role using a reporter gene system and enzyme activity assay, respectively. Additional statistical analysis was performed to study the interaction between the 2 TPH genes in 205 study participants with TPH1 and TPH2 genotype data.Results: Significant haplotype association of TPH2 polymorphisms and BPD was identified (P Ͻ.001). In addition, allelic alteration of polymorphisms in the promoter region and exon 2 of TPH2 caused noteworthy functional losses in promoter and enzyme activities, respectively, indicating the potential susceptibility loci for BPD. We found that the odds ratio changed from 3.73 of the TAG haplotype to 4.81 or 1.68, depending on the combined effect of both TPH genotypes. These data suggested an interaction between the 2 TPH genes to confer a risk for BPD.Conclusions: This study supports the involvement of TPH2 in the etiology of BPD, and the functional singlenucleotide polymorphisms identified herein might be the susceptibility loci for BPD. Although the interaction between the 2 TPH genes merits further investigation, our findings suggest that the interactive effect should be considered in future studies of serotonin-related disorders.

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Differential tissue distribution of tryptophan hydroxylase isoforms 1 and 2 as revealed with monospecific antibodies

Cited by 133 publications

References 39 publications

Serotonin Depletion Hampers Survival and Proliferation in Neurospheres Derived from Adult Neural Stem Cells

Serotonin Depletion Hampers Survival and Proliferation in Neurospheres Derived from Adult Neural Stem Cells

Glucocorticoid modulation of tryptophan hydroxylase-2 protein in raphe nuclei and 5-hydroxytryptophan concentrations in frontal cortex of C57/Bl6 mice

Association of Functional Polymorphisms of the Human Tryptophan Hydroxylase 2 Gene With Risk for Bipolar Disorder in Han Chinese

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