No abstract

Abstract. Mechanistic target of rapamycin (mTOR) is a conserved serine/threonine kinase important in cell proliferation, growth and protein translation. Rapamycin, a well-known anti-cancer agent and immunosuppressant drug, inhibits mTOR activity in different taxa including zebrafish. In the present study, the effect of rapamycin exposure on the transcriptome of a zebrafish fibroblast cell line, ZF4, was investigated. Microarray analysis demonstrated that rapamycin treatment modulated a large set of genes with varying functions including protein synthesis, assembly of mitochondrial and proteasomal machinery, cell cycle, metabolism and oxidative phosphorylation in ZF4 cells. A mild however, coordinated reduction in the expression of proteasomal and mitochondrial ribosomal subunits was detected, while the expression of numerous ribosomal subunits increased. Meta-analysis of heterogeneous mouse rapamycin microarray datasets enabled the comparison of zebrafish and mouse pathways modulated by rapamycin, using Kyoto Encyclopedia of Genes and Genomes and Gene Ontology pathway analysis. The analyses demonstrated a high degree of functional conservation between zebrafish and mice in response to rapamycin. In addition, rapamycin treatment resulted in a marked dose-dependent reduction in body size and pigmentation in zebrafish embryos. The present study is the first, to the best of our knowledge, to evaluate the conservation of rapamycin-modulated functional pathways between zebrafish and mice, in addition to the dose-dependent growth curves of zebrafish embryos upon rapamycin exposure.

No abstract

Robo2, a member of the robo gene family, functions as a repulsive axon guidance receptor as well as a regulator of cell migration and tissue morphogenesis in different taxa. In this study, a novel isoform of the zebrafish robo2 (robo2_tv2), which included an otherwise alternatively spliced exon (CAE), has been characterized. Robo2_tv2 is expressed differentially in most non-neuronal tissues of adult zebrafish whereas robo2_tv1 expression to a great extent is restricted to the brain and eye. In zebrafish, robo2_tv2 exhibits a very-low-level basal expression starting from 1 day post fertilization until the mid-larval stages, at which time its expression increases dramatically and could be detected throughout adulthood. Our findings demonstrate that the amino acid sequence coded by CAE of the robo2 gene is highly conserved between zebrafish and mammals, and also contains conserved motifs shared with robo1 and robo4 but not with robo3. Furthermore, we provide an account of differential transcription of the CAE homolog in various tissues of the adult rat. These results suggest that the alternatively spliced robo2 isoforms may exhibit tissue specificity.

No abstract

Purpose Cholinergic signals can be important modulators of cellular signaling in cancer. We recently have shown that knockdown of nicotinic acetylcholine receptor subunit alpha 5, CHRNA5, diminishes the proliferative potential of breast cancer cells. However, modulation of CHRNA5 expression in the context of estrogen signaling and its prognostic implications in breast cancer remained unexplored. Methods Meta-analyses of large breast cancer microarray cohorts were used to evaluate the association of CHRNA5 expression with estrogen (E2) treatment, estrogen receptor (ER) status and patient prognosis. The results were validated through RT-qPCR analyses of multiple E2 treated cell lines, CHRNA5 depleted MCF7 cells and across a breast cancer patient cDNA panel. We also calculated a predicted secondary (PS) score representing direct/indirect induction of gene expression by E2 based on a public dataset (GSE8597). Co-expression analysis was performed using a weighted gene co-expression network analysis (WGCNA) pipeline. Multiple other publicly available datasets such as CCLE, COSMIC and TCGA were also analyzed. Results Herein we found that CHRNA5 expression was induced by E2 in a dose-and time-dependent manner in breast cancer cell lines. ER − breast tumors exhibited higher CHRNA5 expression levels than ER + tumors. Independent meta-analysis for survival outcome revealed that higher CHRNA5 expression was associated with a worse prognosis in untreated breast cancer patients. Furthermore, CHRNA5 and its co-expressed gene network emerged as secondarily induced targets of E2 stimulation. These targets were largely downregulated by exposure to CHRNA5 siRNA in MCF7 cells while the response of primary ESR1 targets was dependent on the direction of the PS-score. Moreover, primary and secondary target genes were uncoupled and clustered distinctly based on multiple public datasets. Conclusion Our findings strongly associate increased expression of CHRNA5 and its co-expression network with secondary E2 signaling and a worse prognosis in breast cancer.

No abstract

<b><i>Background:</i></b> Airway epithelial cells are constantly exposed to intracellular and extracellular proteases that play a pivotal role in several airway diseases. <i>Dermatophagoides pteronyssinus</i> (Der p) 1 derived from house dust mite has protease activity that causes epithelial barrier defect and inflammatory response. Protease inhibitors released against proteases are involved in the maintenance of homeostasis. A disruption of the balance between proteases and protease inhibitors can lead to distortion of the cellular structures and cellular activities and thus culminate in disease processes. Although the effects of Der p 1 allergen on epithelial barrier integrity and inflammatory response are well-established, its contribution to protease inhibitor production is highly limited. <b><i>Objective:</i></b> This study aimed to determine the profile of the protease inhibitor response to Der p 1 allergen in human airway epithelial cells, A549 and BEAS-2B. <b><i>Methods:</i></b> Differentiated cells by the air-liquid interface were exposed to Der p 1 with or without Th2 type cytokines (IL-4 and IL-13). Gene expression of protease inhibitors was determined by qPCR at 2 different time points. <b><i>Results:</i></b> We found that the effect of allergen exposure on the protease inhibitor profile can vary depending on the antigen concentration, treatment duration, and the presence or absence of type 2 cytokines. Gene expressions of serine protease inhibitor (<i>SERPIN</i>)<i>B3</i> and <i>SERPINB4</i> were increased following Th2 cytokine stimulation in both cell types at both time points, whereas <i>SERPINB2</i> and <i>TFPI-2</i> expressions were induced by 24-h Der p 1 stimulation in both cells. <b><i>Conclusions:</i></b> Our study suggests that Der p 1 exposure of the airway epithelium may have consequences related to its protease activity in the presence as well as in the absence of Th2 cytokines in the microenvironment.