Effect of lipopolysaccharide on the gene expression of the enzymes involved in tetrahydrobiopterin de novo biosynthesis in murine neuroblastoma cell line N1E-115

The amounts of messenger RNA for three enzymes, namely guanosine triphosphate (GTP) cyclohydrolase I, 6-pyruvoyltetrahydropterin synthase, and sepiapterin reductase, all of which are involved in the de novo biosynthesis of (6R)-L-erythrodihydroxypropyl-2-amino-4-hydroxy-5,6,7,8- tetrahydropteridine (BH₄) from GTP, were measured quantitatively in murine neuroblastoma cell line N1E-115 by the competitive polymerase chain reaction (PCR) technique after reverse transcription using a heterologous DNA fragment as an internal standard. Twenty-four hour activation of this cell line with 1 μg/ml lipopolysaccharide resulted in statistically significant increases in the amounts of the messages of all three enzymes. Our data suggest that lipopolysaccharide can activate the intrinsic pathway resulting in the enhanced gene expression of these three enzymes in neuron-derived cells such as N1E-115.