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Induced pluripotent stem (iPS) cells differentiated into neural progenitor cells (NPCs) hold great potential as a tool for modeling brain disease. When coupled to high content screening (HCS), NPCs may become a powerful tool for drug discovery. One of the goals of the new Molecular Biology and Cell Reprogramming, headed by Dr. Stevens Rehen at the D'Or Institute for Research and Education, is to develop a high content screening (HCS) strategy to study human brain diseases through the use of iPS. As a starting point, the effects of psychoactive drugs were characterized in NPCs by using HCS. Thousands of cells and single mitochondria were analyzed individually by HCS software and submitted to several sequences of morphometric analyses and fluorescence quantification. Morphological and functional alterations in mitochondria, which can be linked to energetic metabolism failure, a key trigger to abnormal neuronal development, were also observed. I will discuss the impact of HCS technology applied to neural stem cells as an attractive platform to drug discovery, cytotoxicity assessment and disease modeling. Supported by: BNDES, CNPq, FINEP, CAPES and FAPERJ.

Complementary DNA, encoding the mitochondrial enzyme NADH-ubiquinone oxidoreductase subunit 5 (SmND5) of the human parasite Schistosoma mansoni was isolated by screening a S. mansoni cDNA library with a human androgen receptor (hAR) cDNA probe. The complete nucleotide and deduced aminoacid sequences of SmND5 were determined. Southern blot analysis revealed the occurrence of a single copy gene for SmND5 and by means of RT-PCR, it was shown that sex- and stage-specific expression of SmND5 occurred. In order to establish a functional relationship between the mitochondrial enzyme and the androgen receptor, the effects of testosterone were compared to those of classical respiratory chain inhibitors, using adult schistosome and beef heart submitochondrial particles. Physiological concentrations of testosterone were able to inhibit the maintenance of proton gradient across the mitochondrial membranes, as well as ATP synthesis. The steroid was found to be cytotoxic to the larvae, but not to adult schistosomes. A model is proposed to explain the observed in vivo testosterone-related differences in worm burdens, in experimental chronic infections.