Defects of mitochondrial electron transport
enzymes have been implicated in the pathogenesis of several
neurodegenerative diseases. In previous work, we reported decreased
protein levels of mitochondrial electron transport
enzyme subunits in adult brain with
Down syndrome (DS). However it is not clear whether cellular damage due to
mitochondrial defects in brain of DS fetus begins in utero. Here we investigated the
protein levels of mitochondrial electron transport
enzymes in fetal DS brain using the proteomic technologies. Two-dimensional (2-D) gel electrophoresis, matrix-assisted
laser desorption ionization mass spectroscopy (MALDI-MS) and specific software for quantification were used. The
protein levels of complex I 30-kDa subunit were significantly decreased in cerebral cortex of fetal DS brain. We conclude that decreased mitochondrial electron transport
enzyme subunits in fetal DS brains could contribute to the impaired energy and
free radical metabolism affecting brain development in DS fetus. Furthermore, the defects of mitochondrial electron
enzymes shown in adult DS brains could begin in utero and continue during the life span of the individual with DS.