Taurine fails to protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced striatal dopamine depletion in mice

The influence of AAV2-mediated gene transfer of human IL-10 on neurodegeneration and immune response in a murine model of Parkinson's disease

BACKGROUND

The aim of this study was to examine the effect of AAV2-hIL-10 (vector containing cDNA for human interleukin 10) on dopaminergic system activity (measured as DA levels and TH mRNA expression in mouse striata), and other monoamine and amino acid neurotransmitters concentration as well as development of inflammatory processes (measured as TGF-β, IFN-γ and GFAP mRNA expression) in a murine MPTP neurotoxicant model of Parkinson's disease.

METHODS

Male C57BL/6 mice 12 months-old were used in this study. AAV2-hIL-10 vector was bilaterally administered into striatum at 14, 21 or 28 days prior to MPTP intoxication. Animals were sacrificed at 7 days following MPTP injection. The expression of hIL-10 (human interleukin 10) was examined by ELISA. Striatal monoamine and amino acid neurotransmitters were measured by HPLC method. TH, TGF-β, IFN-γ and GFAP mRNA expression was examined by RT-PCR method.

RESULTS

MPTP treatment dramatically reduced DA levels and decreased TH mRNA expression in mouse striata, effects that were significantly impeded by AAV2-hIL-10 administration prior to MPTP intoxication. AAV2-hIL-10 infusion increased IFN-γ, TGF-β and GFAP mRNA expression.

CONCLUSIONS

Our data suggest that the transfer of AAV2-hIL-10 into the striatum may play a neuroprotective role in the mouse MPTP model of PD and these effects are mediated by the anti-inflammatory action of IL-10.

Comparative study of taurine and tauropyrone: GABA receptor binding, mitochondrial processes and behaviour

OBJECTIVES

Taurine, a sulfur-containing amino acid, has high hydrophilicity and is poorly absorbed. Tauropyrone, a taurine-containing 1,4-dihydropyridine derivative, is suggested to have greater activity than taurine owing to improved physicochemical properties that facilitate delivery of the compound to target cells. The aim of this study was to determine whether the 1,4-dihydropyridine moiety in tauropyrone improves the pharmacological efficacy of taurine in vitro and in vivo.

METHODS

The effects of taurine and tauropyrone, as well as of the 1,4-dihydropyridine moiety were compared in in-vitro experiments to determine the binding to GABA receptors and influence on mitochondrial processes (isolated rat liver mitochondria), and in in-vivo tests to assess the influence on behavioural effects caused by the GABA-A receptor ligands, bicuculline, diazepam and ethanol.

KEY FINDINGS

Unlike taurine, tauropyrone did not display binding activity for the GABA-A receptor, and only taurine (but not tauropyrone) at low doses (0.1, 1.0 and 10 mg/kg) antagonised the bicuculline-induced convulsion effect. Taurine and tauropyrone had no effect on diazepam myorelaxing action, and they both exerted a comparable 'anti-ethanol' effect (shortening of the ethanol-sleeping time). Taurine and tauropyrone did not influence processes of mitochondrial bioenergetics.

CONCLUSIONS

The action of tauropyrone at the level of the GABA-A receptor differs qualitatively from that of taurine, probably because of its 1,4-dihydropyridine moiety, which may hinder access to the GABA-A receptor GABA site. Tauropyrone does not show improved pharmacological efficacy in in-vitro and in-vivo studies in comparison with taurine.