ETS2 regulating neurodegenerative signaling pathway of human neuronal (SH-SY5Y) cells exposed to single and repeated low-dose sarin (GB).

The mechanistic understanding of low-level sarin-induced neurotoxicity after single or repeated doses has yet to be explored at a cellular level. Using the microarray (Affymetrix-GeneChips) transcription profiling approach, the present study examined gene expression in human SH-SY5Y cells exposed to single (3 and 24 h) or repeated (2 x 24 h) doses of sarin (5 microg/mL) to delineate the possible mechanism. Two hundred twenty-four genes whose expression was significantly (P < 0.01) altered by at least 3-fold were selected by GeneSpringGX analysis. The comparative gene expression data confirmed the transcriptional changes to be related to dose and exposure time of sarin. The effect of a single noncytotoxic sarin dose on gene transcription was variable, whereas repeated doses over 48 h persistently down-regulated genes linked to neurodegenerative mechanisms. Thirty persistently altered genes were validated using real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Similar qRT-PCR profiles obtained in sarin-treated SH-SY5Y and HCN-1A cells confirmed the cell-independent alterations in expression levels. Genes (ETS2, APOE, PSEN1, DDC, and CD9) implicated mainly in the regulation of sarin-induced neuropathogenesis were further confirmed by Western blot and double-immunofluorescence assays. The regulome pathway suggests a new feasible mechanism by which sarin increases ETS2 expression and takes control over other genes involved in the neurodegenerative pathway. The overall data delineate an in vitro experimental model suitable for studying the neuropathology of cells and may provide novel insights into therapeutic interventions.

Transcriptome profiling of neuronal model cell PC12 from rat pheochromocytoma.

GeneChip microarray is a cutting-edge technology being used to study the expression patterns of genes with in a particular cell type. In this study, the Affymetrix RAE230A platform was used to profile stably expressed mRNA transcripts from PC12 cells at passage 5 and 15. The whole-cell PC12 transcriptome revealed that a total of 7,531 stable transcripts (P < 0.05), corresponding to 6,785 genes, were found to be consistently expressed between passage 5 and 15. The data analysis revealed 3,080 functional proteins, belonging to 13 families, which indicate that about 65% of the proteins expressed in PC12 cells are uncharacterized. By using our custom-built rat neuronal reference genome database, we mapped endogenously expressed stable neuronal transcripts from PC12 cells comprising about 765 genes responsible for neuronal function and disease. These neuronal transcripts were further analyzed to provide a genetic blueprint that can be used by neurobiologist to unravel the complex cellular and molecular mechanisms underlying biological functions and their associated signalling networks for diseases affecting the nervous system.