Effect
of phenylalanine and its metabolites on the neuronal differentiation of P19
cell: POSSIBLE relevance in maternal phenylketonuria
Qiu WJ, Pan J, Gu XF
Xin Hua
Hospital, Shanghai Second Medical University, Shanghai, China
Objective: If a low-phenylalanine
(Phe) diet is not maintained during pregnancy, phenylketonuric women will
born an offspring with mental retardation and microcephaly. P19 cell line
is a suitable model system to analyze regulation of neuronal
differentiation. In this study, P19 cell was used to test the hypothesis
that the microcephaly and mental retardation may be a result of the
disturbing effect of Phe and its metabolites during neuronal
differentiation stage of embryogenesis.
Methods: Phe or phenylacetic
acid (PAA) or phenyllactic acid (PLA) was used to treat P19 cell from
exposure of aggregated P19 cell to retinoic acid to induce cell
differentiation till end of the experiment. After plated for neuronal
differentiation, cell morphology was observed under light microscope. P19
cell viability was determined by mitochondrial MTT reduction and cellular
LDH release. Immunohistochemistry of NF was used to show the survival P19
neuron. Cell cycle analysis was performed using flow cytometry after 3 days
induction of P19 cell by retinoic acid. .
Results: The P19 neurons
exposed to Phe and its metabolites showed various changes such as cell
swelling, nucleus shifting to the cell periphery, weaker NF staining and so
on. Phe, PAA, PLA remarkably decreased the viability of P19 cells and P19
neurons without altering celluler LDH release. The ratio of multipolar
neurons to bipolar/monopolar neurons treated by Phe, PAA, PLA was lower
than that of control group(p<0.01). While, flow cytometry revealed that
Phe , PAA, PLA had no effects on the cell cycle.
Conclusion: Our date showed a
primary effect of Phe or its metabolites on P19 cell neuronal
differentiation, and suggest Phe or its metabolites might involved in the
CNS dysfunction associated with maternal PKU.