Microarray analysis on human neuroblastoma cells exposed to aluminum, ß(1-42)-amyloid or the ß(1-42)-amyloid aluminum complex.

BACKGROUND: A typical pathological feature of Alzheimer's disease (AD) is the appearance in the brain of senile plaques made up of ß-amyloid (Aß) and neurofibrillary tangles. AD is also associated with an abnormal accumulation of some metal ions, and we have recently shown that one of these, aluminum (Al), plays a relevant role in affecting Aß aggregation and neurotoxicity. METHODOLOGY: In this study, employing a microarray analysis of 35,129 genes, we investigated the effects induced by the exposure to the Aß(1-42)-Al (Aß-Al) complex on the gene expression profile of the neuronal-like cell line, SH-SY5Y. PRINCIPAL FINDINGS: The microarray assay indicated that, compared to Aß or Al alone, exposure to Aß-Al complex produced selective changes in gene expression. Some of the genes selectively over or underexpressed are directly related to AD. A further evaluation performed with Ingenuity Pathway analysis revealed that these genes are nodes of networks and pathways that are involved in the modulation of Ca(2+) homeostasis as well as in the regulation of glutamatergic transmission and synaptic plasticity. CONCLUSIONS AND SIGNIFICANCE: Aß-Al appears to be largely involved in the molecular machinery that regulates neuronal as well as synaptic dysfunction and loss. Aß-Al seems critical in modulating key AD-related pathways such as glutamatergic transmission, Ca(2+) homeostasis, oxidative stress, inflammation, and neuronal apoptosis.

Microarray analysis during adipogenesis identifies new genes altered by antiretroviral drugs.

OBJECTIVE: To elucidate the pathogenesis of HAART-associated lipodystrophy, by investigating the effects of antiretroviral drugs on adipocyte differentiation and gene expression profile. DESIGN AND METHODS: Analysis of gene expression profile by DNA microarrays and quantitative RT-PCR of 3T3-L1 preadipocytes treated with the nucleoside reverse transcriptase inhibitors (NRTI) lamivudine, zidovudine, stavudine, and zalcitabine, and with the protease inhibitors (PI) indinavir, saquinavir, and lopinavir during maturation into adipocytes. RESULTS: Under standard adipogenic differentiation protocols, PI significantly inhibited adipocyte differentiation, as demonstrated by cell viability assay and Oil Red O staining and quantification, whereas NRTI had mild effects on adipogenesis. Gene expression profile analysis showed that treatment with NRTI modulated the expression of transcription factors, such as Aebp1, Pou5f1 and Phf6, which could play a key role in the determination of the adipocyte phenotype. PI also modulated gene expression toward inhibition of adipocyte differentiation, with up-regulation of the Wnt signaling gene Wnt10a and down-regulation of the expression of genes encoding master adipogenic transcription factors (e.g., C/EBPalpha and PPARgamma), oestrogen receptor beta, and adipocyte-specific markers (e.g., Adiponectin, Leptin, Mrap, Cd36, S100A8). CONCLUSIONS: This study identifies new genes modulated by PI and NRTI in differentiating adipocytes. Abnormal expression of these genes, which include master adipogenic transcription factors and genes involved in lipid metabolism and cell cycle control, could contribute to the understanding of the pathogenesis of HAART-associated lipodystrophy.

Loss of growth hormone secretagogue receptor 1a and overexpression of type 1b receptor transcripts in human adrenocortical tumors.

OBJECTIVE AND METHODS: Quantitative analysis of mRNA expression of ghrelin and its receptors GHS-R1a and -R1b in a large series of normal and neoplastic human adrenocortical tissues. Evaluation of the effects of ghrelin on GHS-R expression and proliferation of human adrenocortical carcinoma (ACC) cell lines. RESULTS: Ghrelin and GHS-R transcripts are expressed in normal adrenal cortex, with GHS-R1b mRNA levels being 5- to 10-fold higher than GHS-R1amRNA. A significant increase in ghrelin expression was observed in adrenocortical adenomas, but not in carcinomas. GHS-R1a was undetectable in about 60% of both benign and malignant tumor samples, except for cortisol-producing adenomas, which showed increased receptor expression. At variance, GHS-R1b was overexpressed in both benign and malignant adrenocortical tumors. In vitro studies in human ACC cell lines demonstrated that GHS-R1a is downregulated and GHS-R1bmRNA expression is upregulated by ghrelin, while inhibiting cell proliferation. CONCLUSION: Downregulation ofGHS-R1a in adrenal tumors and the presence of high levels of GHS-R1b transcripts in adrenocortical tissue suggest a role for these receptors in adrenal function and growth. In this regard, ghrelin inhibits cell proliferation and modulates GHS-R expression in ACC cells in vitro.