New insights into tetrahydrobiopterin pharmacodynamics from Pah enu1/2, a mouse model for compound heterozygous tetrahydrobiopterin-responsive phenylalanine hydroxylase deficiency
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New insights into tetrahydrobiopterin pharmacodynamics from Pah enu1/2, a mouse model for compound heterozygous tetrahydrobiopterin-responsive phenylalanine hydroxylase deficiency. / Lagler, Florian B; Gersting, Søren W; Zsifkovits, Clemens; Steinbacher, Alice; Eichinger, Anna; Danecka, Marta K; Staudigl, Michael; Fingerhut, Ralph; Glossmann, Hartmut; Muntau, Ania C.
In: BIOCHEM PHARMACOL, Vol. 80, No. 10, 15.11.2010, p. 1563-71.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - New insights into tetrahydrobiopterin pharmacodynamics from Pah enu1/2, a mouse model for compound heterozygous tetrahydrobiopterin-responsive phenylalanine hydroxylase deficiency
AU - Lagler, Florian B
AU - Gersting, Søren W
AU - Zsifkovits, Clemens
AU - Steinbacher, Alice
AU - Eichinger, Anna
AU - Danecka, Marta K
AU - Staudigl, Michael
AU - Fingerhut, Ralph
AU - Glossmann, Hartmut
AU - Muntau, Ania C
N1 - Copyright © 2010 Elsevier Inc. All rights reserved.
PY - 2010/11/15
Y1 - 2010/11/15
N2 - Phenylketonuria (PKU), an autosomal recessive disease with phenylalanine hydroxylase (PAH) deficiency, was recently shown to be a protein misfolding disease with loss-of-function. It can be treated by oral application of the natural PAH cofactor tetrahydrobiopterin (BH(4)) that acts as a pharmacological chaperone and rescues enzyme function in vivo. Here we identified Pah(enu1/2) bearing a mild and a severe mutation (V106A/F363S) as a new mouse model for compound heterozygous mild PKU. Although BH(4) treatment has become established in clinical routine, there is substantial lack of knowledge with regard to BH(4) pharmacodynamics and the effect of the genotype on the response to treatment with the natural cofactor. To address these questions we applied an elaborate methodological setup analyzing: (i) blood phenylalanine elimination, (ii) blood phenylalanine/tyrosine ratios, and (iii) kinetics of in vivo phenylalanine oxidation using (13)C-phenylalanine breath tests. We compared pharmacodynamics in wild-type, Pah(enu1/1), and Pah(enu1/2) mice and observed crucial differences in terms of effect size as well as effect kinetics and dose response. Results from in vivo experiments were substantiated in vitro after overexpression of wild-type, V106A, and F263S in COS-7 cells. Pharmacokinetics did not differ between Pah(enu1/1) and Pah(enu1/2) indicating that the differences in pharmacodynamics were not induced by divergent pharmacokinetic behavior of BH(4). In conclusion, our findings show a significant impact of the genotype on the response to BH(4) in PAH deficient mice. This may lead to important consequences concerning the diagnostic and therapeutic management of patients with PAH deficiency underscoring the need for individualized procedures addressing pharmacodynamic aspects.
AB - Phenylketonuria (PKU), an autosomal recessive disease with phenylalanine hydroxylase (PAH) deficiency, was recently shown to be a protein misfolding disease with loss-of-function. It can be treated by oral application of the natural PAH cofactor tetrahydrobiopterin (BH(4)) that acts as a pharmacological chaperone and rescues enzyme function in vivo. Here we identified Pah(enu1/2) bearing a mild and a severe mutation (V106A/F363S) as a new mouse model for compound heterozygous mild PKU. Although BH(4) treatment has become established in clinical routine, there is substantial lack of knowledge with regard to BH(4) pharmacodynamics and the effect of the genotype on the response to treatment with the natural cofactor. To address these questions we applied an elaborate methodological setup analyzing: (i) blood phenylalanine elimination, (ii) blood phenylalanine/tyrosine ratios, and (iii) kinetics of in vivo phenylalanine oxidation using (13)C-phenylalanine breath tests. We compared pharmacodynamics in wild-type, Pah(enu1/1), and Pah(enu1/2) mice and observed crucial differences in terms of effect size as well as effect kinetics and dose response. Results from in vivo experiments were substantiated in vitro after overexpression of wild-type, V106A, and F263S in COS-7 cells. Pharmacokinetics did not differ between Pah(enu1/1) and Pah(enu1/2) indicating that the differences in pharmacodynamics were not induced by divergent pharmacokinetic behavior of BH(4). In conclusion, our findings show a significant impact of the genotype on the response to BH(4) in PAH deficient mice. This may lead to important consequences concerning the diagnostic and therapeutic management of patients with PAH deficiency underscoring the need for individualized procedures addressing pharmacodynamic aspects.
KW - Animals
KW - Biopterin
KW - Breath Tests
KW - Disease Models, Animal
KW - Dose-Response Relationship, Drug
KW - Heterozygote
KW - Mice
KW - Mice, Mutant Strains
KW - Mutation
KW - Phenylalanine
KW - Phenylalanine Hydroxylase
KW - Phenylketonurias
KW - Treatment Outcome
KW - Tyrosine
U2 - 10.1016/j.bcp.2010.07.042
DO - 10.1016/j.bcp.2010.07.042
M3 - SCORING: Journal article
C2 - 20705059
VL - 80
SP - 1563
EP - 1571
JO - BIOCHEM PHARMACOL
JF - BIOCHEM PHARMACOL
SN - 0006-2952
IS - 10
ER -