Project description:Transcriptional profiling of U937 scramble vs shHDAC2 before and after SAHA treatment at 5µM concentration for 6 and 24 hours. Different Experimental Conditions: U937 scramble (U937 trasfected with empty vector) vs shHDAC2 (U937 trasfected with shHDAC2 vector), untreated and treated with SAHA at 5 µM concentration for 6h and 24h. Biological replicates: 2 for each sample, independently grown and harvested at 6 and 24 hours. One replicate per array.
Project description:Histone deacetylase (Hdac) inhibitors are used clinically to treat cancer and epilepsy. Although Hdac inhibition accelerates osteoblast maturation and suppresses osteoclast maturation in vitro, the effects of Hdac inhibitors on the skeleton are not understood. The purpose of this study was to determine how the pan-Hdac inhibitor, suberoylanilide hydroxamic acid (SAHA; a.k.a. vorinostat or Zolinza(TM)) affects bone mass and remodeling in vivo. Male C57BL/6J mice received daily SAHA (100mg/kg) or vehicle injections for 3 to 4weeks. SAHA decreased trabecular bone volume fraction and trabecular number in the distal femur. Cortical bone at the femoral midshaft was not affected. SAHA reduced serum levels of P1NP, a bone formation marker, and also suppressed tibial mRNA levels of type I collagen, osteocalcin and osteopontin, but did not alter Runx2 or osterix transcripts. SAHA decreased histological measures of osteoblast number but interestingly increased indices of osteoblast activity including mineral apposition rate and bone formation rate. Neither serum (TRAcP 5b) nor histological markers of bone resorption were affected by SAHA. P1NP levels returned to baseline in animals which were allowed to recover for 4weeks after 4weeks of daily SAHA injections, but bone density remained low. In vitro, SAHA suppressed osteogenic colony formation, decreased osteoblastic gene expression, induced cell cycle arrest, and caused DNA damage in bone marrow-derived adherent cells. Collectively, these data demonstrate that bone loss following treatment with SAHA is primarily due to a reduction in osteoblast number. Moreover, these decreases in osteoblast number can be attributed to the deleterious effects of SAHA on immature osteoblasts, even while mature osteoblasts are resistant to the harmful effects and demonstrate increased activity in vivo, indicating that the response of osteoblasts to SAHA is dependent upon their differentiation state. These studies suggest that clinical use of SAHA and other Hdac inhibitors to treat cancer, epilepsy or other conditions may potentially compromise skeletal structure and function.
Project description:Design: Persistent latently infected CD4+ T cells represent a major obstacle to HIV eradication. Histone deacetylase inhibitors (HDACis) are a promising activation therapy in a “shock and kill” strategy. However, off-target effects of HDACis on host gene expression are poorly understood in primary cells of the immune system. We hypothesized that HDACi-modulated genes would be best identified with a dose response analysis. Methods: Resting primary CD4+ T cells were treated with increasing concentrations (0.34, 1, 3, or 10 μM) of the HDACi, suberoylanilide hydroxamic acid (SAHA), for 24 hours and then subjected to microarray gene expression analysis. Genes with dose-correlated expression were identified with a likelihood ratio test using Isogene GX and a subset of these genes with a consistent trend of up or downregulation at each dose of SAHA were identified as dose-responsive. Histone modifications were characterized in promoter regions of the top 6 SAHA dose-responsive genes by RT-qPCR analysis of immunopreciptated chromatin (ChIP). Results: A large number of genes were shown to be up (N=657) or down (N=725) regulated by SAHA in a dose-responsive manner (FDR p-value < 0.05 and fold change ≥ |2|). Several of these genes (CTNNAL1, DPEP2, H1F0, IRGM, PHF15, and SELL) are potential in vivo biomarkers of SAHA activity. SAHA dose-responsive gene categories included transcription factors, HIV restriction factors, histone methyltransferases, and host proteins that interact with HIV proteins or the HIV LTR. Pathway analysis suggested net downregulation of T cell activation with increasing SAHA dose. Histone acetylation was not correlated with host expression, but plausible alternative mechanisms for SAHA-modulated expression were identified. Conclusions: Numerous host genes in CD4+ T cells are modulated by SAHA in a dose-responsive manner, including genes that may negatively influence HIV activation from latency. Our study suggests that SAHA influences gene expression through a confluence of several mechanisms, including histone acetylation, histone methylation, and altered expression and activity of transcription factors.
Project description:Transcriptional profiling of U937 miR-194-5p (UmiR-194-5p) vs U937 miR-194-5p (UmiR-194-5p) treated with SAHA (Vorinostat; suberoylanilide hydroxamic acid) for 24 h at 5uM concetration
Project description:This study evaluated primary CD4+ T cell gene expression treated with pharmacologically achievable concentration (340 nM) of SAHA for 24 hours in order to evaluate potential side effects of this compound in cells relevant to HIV infection. Analysis of human primary CD4+ T cells taken from 9 healthy donors treated with 340 nM of SAHA for 24 hours. Results identify genes modulated by SAHA treatment in human primary CD4+ T cells.
Project description:To elucidate the molecular mechanism involved in increased tolerance to high-salinity stress by the application of HDAC inhibitor named SAHA
Project description:Suberoylanilide hydroxamic acid (SAHA) has been assessed in clinical trials as part of a “shock and kill” strategy to cure HIV-infected patients. While it was effective at inducing expression of HIV RNA "shock" , treatment with SAHA did not result in the reduction of reservoir size "kill". We therefore utilized a systems biology approach to dissect the mechanisms of action of SAHA that may explain its limited success in “shock and kill” strategies. CD4+ T cells from HIV seronegative donors were treated with 1 uM SAHA or its solvent dimethyl sulfoxide for 24 hours. Differential protein expression and post-translational modification was measured with two-dimensional liquid chromatography - tandem mass spectrometry iTRAQ proteomics. Gene expression changes were assessed by Illumina microarrays. Using limma package in the R computing environment, we identified 185 proteins, 18 phosphorylated forms, 4 acetylated forms and 2,982 genes, whose expression was modulated by SAHA. A protein interaction network integrating these 4 data types identified the transcriptional regulator HMGA1 to be upregulated by SAHA at the transcript, protein and acetylated protein levels. HMGA1 has been shown to repress HIV transcription, which is not optimal with respect to a shock and kill strategy. Further functional category assessment of proteins and genes modulated by SAHA identified gene ontology terms related to NFB signaling, protein folding and autophagy, which are all relevant to HIV reactivation. In summary, this study identified a number of host factors that may be therapeutically targeted to achieve more potent HIV reactivation in the “shock and kill” treatment, when using SAHA, either through modification of SAHA itself or through combination with other latency reversing agents. Finally, proteome profiling highlighted a number of potential adverse effects of SAHA, which transcriptome profiling alone would not have identified.