Over the last decade, small noncoding RNA molecules such as microRNAs (miRNAs) have emerged as critical regulators in the expression and function of eukaryotic genomes. It has been suggested that viral infections and neurological disease outcome may also be shaped by the influence of small RNAs. This has prompted us to suggest that HIV infection alters the endogenous miRNA expression patterns, thereby contributing to neuronal deregulation and AIDS dementia. Therefore, using primary cultures and neuronal cell lines, we examined the impact of a viral protein (HIV-1 Tat) on the expression of miRNAs due to its characteristic features such as release from the infected cells and taken up by noninfected cells. Using microRNA array assay, we demonstrated that Tat deregulates the levels of several miRNAs. Interestingly, miR-34a was among the most highly induced miRNAs in Tat-treated neurons. Tat also decreases the levels of miR-34a target genes such as CREB protein as shown by real time PCR. The effect of Tat was neutralized in the presence of anti-miR-34a. Using in situ hybridization assay, we found that the levels of miR-34a increase in Tat transgenic mice when compared with the parental mice. Therefore, we conclude that deregulation of neuronal functions by HIV-1 Tat protein is miRNA-dependent.
HIV-1 Tat protein promotes neuronal dysfunction through disruption of microRNAs.
Specimen part, Cell line, Treatment
View SamplesStudies have shown that HIV-infected patients develop neurocognitive disorders characterized by neuronal dysfunction. The lack of productive infection of neurons by HIV suggests that viral and cellular proteins, with neurotoxic activities, released from HIV-1-infected target cells can cause this neuronal deregulation. The viral protein R (Vpr), a protein encoded by HIV-1, has been shown to alter the expression of various important cytokines and inflammatory proteins in infected and uninfected cells; however the mechanisms involved remain unclear. Using a human neuronal cell line, we found that Vpr can be taken up by neurons causing: (i) deregulation of calcium homeostasis, (ii) endoplasmic reticulum-calcium release, (iii) activation of the oxidative stress pathway, (iv) mitochondrial dysfunction and v- synaptic retraction. In search for the cellular factors involved, we performed microRNAs and gene array assays using human neurons (primary cultures or cell line, SH-SY5Y) that we treated with recombinant Vpr proteins. Interestingly, Vpr deregulates the levels of several microRNAs (e.g. miR-34a) and their target genes (e.g. CREB), which could lead to neuronal dysfunctions. Therefore, we conclude that Vpr plays a major role in neuronal dysfunction through deregulating microRNAs and their target genes, a phenomenon that could lead to the development of neurocognitive disorders.
Deregulation of microRNAs by HIV-1 Vpr protein leads to the development of neurocognitive disorders.
Specimen part, Cell line, Treatment
View SamplesContinuous stress caused by smoking induces changes in the cell population of small airway epithelium, with basal cell hyperplasia and goblet cell metaplasia at the expense of ciliated cells, and there is now compiling evidence that basal cells play a key role in the early pathogenesis of Chronic Obtructive Pulmonary Disease (COPD).
Microarray analysis identifies defects in regenerative and immune response pathways in COPD airway basal cells.
Specimen part, Disease stage
View SamplesSTAT2 is an essential transcription factor in type I interferon (IFN) signaling. STAT2 is activated following exposure to IFN stimulation by phosphorylation at tyrosine-690. This post-translational modification permits the assembly and nuclear retention of the ISGF3 complex (consisting of STAT1/STAT2/IRF9) to drive gene transcription. We recently identified STAT2 to be serine phosphorylated in an IFN-dependent manner. The biological significance of these novel phosphorylation events in STAT2 remain to be elucidated. Thus far our data show that serine phosphorylation of STAT2 negatively regulates the biological effects of IFN.
No associated publication
Cell line, Treatment
View SamplesWe constructed one-cell stage embryos by maternal pronuclear (mPN) transfer having B6 ooplasm, B6 paternal PN (pPN), and either B6 or C3H mPN (BBB and BCB, respectively). We collected embryos of each type that were either treated (BBB+a, BCB+a) or untreated with -amanitin (BBB, BCB) at the two-cell stage for microarray analysis.
No associated publication
Treatment
View SamplesThe elaboration of a quality oocyte is integrally linked to the correct developmental progression of cumulus cell phenotype. In humans and non-human primates, oocyte quality is diminished with in vitro maturation. To determine the changes in gene expression in rhesus monkey cumulus cells (CC) that occur during the final day prior to oocyte maturation and how these changes differ between in vitro and in vivo maturation (IVM and VVM), we completed a detailed comparison of transcriptomes using the Affymetrix gene array. We observe a large number of genes differing in expression when comparing IVM-CC and VVM-CC directly, but a much larger number of differences comparing the transitions from the pre-oocyte maturation to post- IVM and post-VVM state. We observe a truncation or delay in the normal pattern of gene regulation, but also remarkable compensatory changes in gene expression during IVM. Among the genes affected in cumulus cells by IVM are those that contribute to productive cell-cell interactions between cumulus cell and oocyte and between cumulus cells. Numerous genes involved in lipid metabolism are incorrectly regulated during IVM, and the synthesis of sex hormones appears not suppressed during IVM. We identify a panel of 24 marker genes, the expression of which should provide the foundation for understanding how IVM can be improved, for monitoring IVM conditions, and for diagnosing oocyte quality.
Extensive effects of in vitro oocyte maturation on rhesus monkey cumulus cell transcriptome.
Specimen part
View SamplesThe oocytes of many species, both invertebrate and vertebrate, contain a large collection of localized determinants in the form of proteins and translationally inactive maternal mRNAs. However, it is unknown whether mouse oocytes contain localized MmRNA determinants and what mechanisms might be responsible for their control. We collected intact MII oocytes, enucleated MII oocyte cytoplasts (with the spindle removed), and spindle-chromosome complexes which had been microsurgically removed. RNA was extracted, amplified, labeled, and applied to microarrays to determine if any MmRNA determinants were localized to the SCC.
Association of maternal mRNA and phosphorylated EIF4EBP1 variants with the spindle in mouse oocytes: localized translational control supporting female meiosis in mammals.
Sex, Specimen part, Disease
View SamplesThe transcriptomic response of A. thaliana to 2,5-dichlorobiphenyl (2,5-DCB) and its OH-metabolite, 4'-OH-2,5-DCB, was then examined using whole-genome expression microarrays (Affymetrix).
No associated publication
Age, Specimen part
View SamplesIn vitro oocyte maturation (IVM) holds great promise as a tool for enhancing clinical treatment of infertility, enhancing availability of non human primates for development of disease models, and facilitating endangered species preservation. However, IVM outcomes have remained significantly below success rates obtained using in vivo matured (VVM) oocytes from humans and non human primates. A cDNA array based analysis is presented, comparing the transcriptomes of VVM oocytes with IVM oocytes. We observe a small set of just 59 mRNAs that are differentially expressed between the two cell types. These mRNAs are related to cellular homeostasis, cell-cell interactions including growth factor and hormone stimulation and cell adhesion, and other functions such as mRNA stability and translation. Additionally, we observe in IVM oocytes overexpression of PLAGL1 and MEST, two maternally imprinted genes, indicating a possible interruption or loss of correct epigenetic programming. These results indicate that, under certain IVM conditions, oocytes that are molecularly highly similar to VVM oocytes can be obtained, however the interruption of normal oocyte-somatic cell interactions during the final hours of oocyte maturation may preclude the establishment of full developmental competence.
Effects of in vitro maturation on gene expression in rhesus monkey oocytes.
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View SamplesFollicular somatic cells (mural granulosa cells and cumulus cells) and the oocyte communicate through paracrine interactions and through direct gap junctions between oocyte and cumulus cells. Considering that mural and cumulus cells arise through a common developmental pathway and that their differentiation is essential to reproductive success, understanding how these cells differ is a key aspect to understanding their critical functions. Changes in global gene expression before and after an ovulatory stimulus were compared between cumulus and mural granulosa cells to test the hypothesis that mural and cumulus cells are highly differentiated at the time of an ovulatory stimulus and further differentiate during the periovulatory interval. The transcriptomes of the two cell types were markedly different (>1500 genes) before an ovulatory hCG bolus but converged after ovulation to become completely overlapping. The predominant transition was for the cumulus cells to become more like mural cells after hCG. This indicates that the differentiated phenotype of the cumulus cell is not stable and irreversibly established but may rather be an ongoing physiological response to the oocyte.
Rhesus monkey cumulus cells revert to a mural granulosa cell state after an ovulatory stimulus.
Specimen part
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