Transfection of a Kaposi's sarcoma (KS) herpesvirus (KSHV) Bacterial Artificial Chromosome (KSHVBac36) into mouse bone marrow endothelial-lineage cells generates a cell (mECK36) that forms KS-like tumors in mice. mECK36 expressed most KSHV genes and were angiogenic, but they didn't form colonies in soft agar. In nude mice, mECK36 formed KSHV-harboring vascularized spindle cell sarcomas that were LANA+/podoplanin+, overexpressed VEGF and Angiopoietin ligands and receptors, and displayed KSHV and host transcriptomes reminiscent of KS. mECK36 that lost the KSHV episome reverted to nontumorigenicity. siRNA suppression of KSHV vGPCR, an angiogenic gene upregulated in mECK36 tumors, inhibited angiogenicity and tumorigenicity. These results show that KSHV malignancy is in vivo growth restricted and reversible, defining mECK36 as a biologically sensitive animal model of KSHV-dependent KS.
Kaposi's sarcoma (KS) is the major AIDS-associated malignancy. It isangiogenesis ͉ chemoprevention ͉ hypoxia-inducible factor 1-␣ ͉ reactive oxygen species (ROS) ͉ tumorigenesis
Lytic replication of the Kaposi's sarcoma-associated herpesvirus (KSHV) is essential for the maintenance of both the infected state and characteristic angiogenic phenotype of Kaposi's sarcoma and thus represents a desirable therapeutic target. During the peak of herpesvirus lytic replication, viral glycoproteins are mass produced in the endoplasmic reticulum (ER). Normally, this leads to ER stress which, through an unfolded protein response (UPR), triggers phosphorylation of the ␣ subunit of eukaryotic initiation factor 2 (eIF2␣), resulting in inhibition of protein synthesis to maintain ER and cellular homeostasis. However, in order to replicate, herpesviruses have acquired the ability to prevent eIF2␣ phosphorylation. Here we show that clinically achievable nontoxic doses of the glucose analog 2-deoxy-D-glucose (2-DG) stimulate ER stress, thereby shutting down eIF2␣ and inhibiting KSHV and murine herpesvirus 68 replication and KSHV reactivation from latency. Viral cascade genes that are involved in reactivation, including the master transactivator (RTA) gene, glycoprotein B, K8.1, and angiogenesis-regulating genes are markedly decreased with 2-DG treatment. Overall, our data suggest that activation of UPR by 2-DG elicits an early antiviral response via eIF2␣ inactivation, which impairs protein synthesis required to drive viral replication and oncogenesis. Thus, induction of ER stress by 2-DG provides a new antiherpesviral strategy that may be applicable to other viruses.
Quantification of gene expression is important to confirm changes in levels of gene expression in disease. Prior quantification methods include standard curves, absolute quantification, and relative quantification. This paper describes an analytic method for the relative quantification of Presenilin-1 (PS-1) in neurons and Forkhead-box (FOX) p3 in PBMNCs using real-time PCR analytic techniques. A comparative Ct method (deltadelatCt) is described in which the quantity of target normalized to a normalizer gene reference is given by 2-deltadelatCt where deltadelatCt = [Ct of the gene of interest in the unknown specimen - Ct normalizer gene in the unknown specimen] - [Ct of the gene of interest in the calibrator specimen - Ct normalizer gene in the calibrator specimen]. The calibrator specimen is ideally from a non-treated control specimen and is analyzed on every assay plate with the unknown specimens of interest. The use of the deltadelatCt methodology allows for a higher throughput and a more economical approach to investigate gene expression. We applied this methodology to the quantification of PS-1 and FOXp3 genes and compare the levels of expression by normalizing to different normalizer genes using the deltadelatCt methodology. We find that use of GAPDH is the optimum normalizer gene for the genes analyzed in neurons from human brain and in PBMNCs.
We previously showed that specific strains of human immunodeficiency virus (HIV)-1 infect the brain and contribute to Neuropathology, Cognitive Distress, and Neuropsychiatric Disease. To study further brain disease that results from HIV-1 infection, we commenced analysis of changes in gene expression in brain. We analyzed RNA purified from Frontal Cortex of 5 HIV-1 infected and 4 HIV-1 negative control subjects RNA was amplified and Affymetrix technology was used to analyze gene expression using the 12,585 gene Affymetrix Human Genome U95A chip. The expressed genes showed highly significant Pearsons correlations with each other within the two groups. Expression intensities were transferred to Microsoft Excel and Spotfire was used to analyze the results. Twenty-group K-means cluster analysis was done for HIV+ and HIV- subjects. Genes that were expressed in the same cluster numbers in the two groups were removed from further analysis. Analysis of Gene expression in the top 13 HIV+ clusters showed expression in the 40 gene categories designated in our prior studies. Genes from several categories occurred in more than one K-means cluster. Genes identified in these lists included several genes that have been previously studied: MBP, Myelin-PLP, NMDA receptor, MAG, astrocytic protein, Notch 3, APP, Senescence, proteasome, Ferritin, signaling, cell cycle, iNOS, Chemokine, splicing, synapse, protein tags, and ribosomal proteins. The first (primary significant) axis of both Principal Component Analyses ordered the genes in the same patient groups as the K-means cluster analysis for the respective patient groups. PCA was thus not more informative than K-Means cluster analysis. Ratios of HIV+ to HIV- intensities were calculated for all the averaged gene expression intensities. The ratio range was 0.14 to 9.26. The genes at the extremes (ad extrema) did not correspond to the gene order by K-means clustering (or PCA). The genes in the top 13 K-means clusters showed low-level changes by expression ratio. Genes ad extrema by ratio were in clusters with very large memberships. Mann-Whitney analysis confirmed expression ratio results. Several inferences result from our preliminary study. First, study design will be different in future studies involving additional replicates. Second, ratios inform us of the extent of changes in gene expression quantitatively. Third, Cluster methodology provides us with more subtle information, how bunches (clusters) of genes behave in terms of their centroids (attractors). Fourth, genes that change extensively by ratio tend to be in the larger k-Means clusters. We conclude that ranking gene expression with the use of expression ratio or by K-means clustering, yield different representations of the data.
As a model for Neuropsychiatric dysfunction in NeuroAIDS due to HIV-1 infection and drug abuse, we analyzed gene expression in human neurons treated with cocaine and HIV-1 proteins tat and envelope (env). One-way ANOVA showed statistically significant genes among the treatment groups (p < or = 0.0005). The identified genes were then subjected to a "stepwise" analysis using a repeated measures ANOVA to discover genes with parallel response group profiles across the treatment conditions. These groups were then analyzed using a repeated measures ANOVA to assess treatment main effects and gene-by-treatment interactions within groups. One-way ANOVA produced 35 genes that were significantly associated across all treatment conditions. Factorial analysis of each gene found statistically significant differences: 30--tat, 17--cocaine, 10--env, 6--tat/env, 6--coc/env, and 4--coc/tat. Analyses across genes found three sets of four genes, one set of three genes, and three sets of two genes with parallel profiles. Identified genes had functions included signaling, immune related, and transcription control. The genes were not stochastically arranged on the chromosomes, were in proximity to each other, and to other genes involved in neuropsychiatric diseases. We hypothesize that these genes fall in transcriptionally isolated groups and that abused drugs and HIV-1 proteins trigger transcription overload, coerced expression that may result in damage to the chromosome's control and organization of chromatin transcription machinery.
Links between AIDS and self-injection of drugs were first recognized more than 20 years ago, but identification of a specific pathogen and ways to neutralize it has not led to complete success in preventing transmission of HIV-1 infection among injecting drug users (IDUs). A street ethnographer identified active risk locales (places where IDUs go to inject drugs) and recruited their proprietors into a study of contaminated injection paraphernalia. Collected paraphernalia from locales were analyzed for contamination by HIV-1 using real-time polymerase chain reaction (PCR). Proprietors and clientele of 16 risk locales participated by contributing used paraphernalia and/or agreeing to a blood test (0.5-1 mL drawn by finger stick). Realtime PCR was the primary measure used to determine contamination of injection paraphernalia and blood samples with HIV-1. Of 130 samples collected at baseline, a total of 8 were found to have evidence of HIV-1 contamination by detection of either HIV-1 RNA or DNA. The most serious contamination (up to 600,000 copies per milliliter) was found in ancillary paraphernalia, rather than needle/syringe (N/S) specimens. Only 4 of 74 N/S specimens had any evidence of HIV-1 contamination at all (with very low viral loads), and none had both HIV-1 DNA and RNA. Although IDUs in risk locales in Miami/Dade appear to be taking care of their N/S with regard to contamination by HIV-1, important evidence of contamination in ancillary paraphernalia, especially cookers and cottons, indicates that IDUs may still incur serious risk regardless of how well they care for their N/S. Our observations indicated that IDUs rinsed their N/S before returning them to the proprietors, from whom we eventually collected them, and this rinsing would have masked the contamination to which they were exposed through use of unrinsed cookers and reused cottons.
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