Abstract
Increased dopamine catabolism may be associated with oxidative stress and neuronal cell death in Parkinson's disease. The present study was carried out to examine the effect of dopamine on the expression of heme oxygenase-1 and -2 (HO-1 and HO-2) in human neuroblastomas (SK-N-SH cell line) and the effects of selegiline and antioxidants on this expression. Cells were kept with close control of pH and were incubated with varying concentrations of dopamine (0.1-100 microM) for 24 h. HO-1 and HO-2 cDNA probes were prepared by reverse transcription-polymerase chain reaction amplification. The mRNA expression of HO-1 and HO-2 was measured by Northern blot analysis. The levels of HO-1 mRNA increased after dopamine treatment, in a dose-dependent manner, in all cell lines studied, whereas levels of the two HO-2 transcripts did not. The HO-1 and HO-2 protein expression was analyzed by Western blotting. HO-1 protein was undetectable in untreated SK-N-SH cells and increased after treatment with dopamine. In contrast, the HO-2 protein (36 kDa) was detected in untreated cells and the levels did not change as a result of treatment. Alpha-tocopherol (10-100 microM) and ascorbic acid (100 microM) did not attenuate the effects of dopamine. Selegiline (10 microM) produced significant increase (P < 0.01) in the induction of HO-1 by dopamine (more than six times the control values). The increased expression of HO-1 following dopamine treatment indicates that dopamine produces oxidative stress in this cell line.
Highlights
Idiopathic Parkinson’s disease (IPD) is characterized by a loss of dopamine in the striatum caused by degeneration of dopaminergic neurons in the zona compacta of the substantia nigra [1]
In this study we investigated the effects of dopamine on the levels of mRNAs encoding Heme oxygenase (HO)-1 and HO-2 and protein levels in SKN-SH neuroblastoma, a catecholaminergic human cell line, to determine whether these cells express HO-1 and whether expression is related to cell survival
HO-1 (32 kDa) protein was not detected in the control homogenates from SK-N-SH but was present at detectable levels after treatment with dopamine (1-100 μM)
Summary
Idiopathic Parkinson’s disease (IPD) is characterized by a loss of dopamine in the striatum caused by degeneration of dopaminergic neurons in the zona compacta of the substantia nigra [1]. Oxidative stress is a feature of the biochemical pathology of the disease and may mediate the neuronal loss [24]. HO-1, an inducible enzyme, is a stress response protein [6]. HO-1, but not HO-2, is strongly induced by heme, metals, sulfhydryl compounds, hormones, and certain adverse conditions such as oxidative stress [9,10,11]. It has been reported that dopamine induces the expression of HO-1 in glial-derived cell lines and human endothelial cells [18,19]
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Schedule a callMore From: Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas
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