Gene-expression profiling using suppression-subtractive hybridization and cDNA microarray in rat mononuclear cells in response to welding-fume exposure.
ABSTRACT Welders with radiographic pneumoconiosis abnormalities have shown a gradual clearing of the X-ray identified effects following removal from exposure. In some cases, the pulmonary fibrosis associated with welding fumes appears in a more severe form in welders. Accordingly, for the early detection of welding-fume-exposure-induced pulmonary fibrosis, the gene expression profiles of peripheral mononuclear cells from rats exposed to welding fumes were studied using suppression-subtractive hybridization (SSH) and a cDNA microarray. As such, Sprague-Dawley rats were exposed to a stainless steel arc welding fume for 2 h/day in an inhalation chamber with a 1107.5 +/- 2.6 mg/m3 concentration of total suspended particulate (TSP) for 30 days. Thereafter, the total RNA was extracted from the peripheral blood mononuclear cells, the cDNA synthesized from the total RNA using the SMART PCR cDNA method, and SSH performed to select the welding-fume-exposure-regulated genes. The cDNAs identified by the SSH were then cloned into a plasmid miniprep, sequenced and the sequences analysed using the NCBI BLAST programme. In the SSH cloned cDNA microarray analysis, five genes were found to increase their expression by 1.9-fold or more, including Rgs 14, which plays an important function in cellular signal transduction pathways; meanwhile 36 genes remained the same and 30 genes decreased their expression by more than 59%, including genes associated with the immune response, transcription factors and tyrosine kinases. Among the 5200 genes analysed, 256 genes (5.1%) were found to increase their gene expression, while 742 genes (15%) decreased their gene expression in response to the welding-fume exposure when tested using a commercial 5.0k DNA microarray. Therefore, unlike exposure to other toxic substances, prolonged welding-fume exposure was found to substantially downregulate many genes.
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ABSTRACT: Repeated exposure to welding fumes promotes a reversible increase in pulmonary disease risk, but the molecular mechanisms by which welding fumes induce lung injury and how the lung recovers from such insults are unclear. In the present study, pulmonary function and gene-expression profiles in the lung were analyzed by Affymetrix GeneChip microarray after 30 days of consecutive exposure to manual metal arc welding combined with stainless-steel (MMA-SS) welding fumes, and again after 30 days of recovery from MMA-SS fume exposure. In total, 577 genes were identified as being either up-regulated or down-regulated (over twofold changes, p < 0.05) in the lungs of low-dose or high-dose groups. Differentially expressed genes were classified based on a k-means clustering algorithm and biological functions and molecular networks were further analyzed using Ingenuity Pathways Analysis. Among the genes affected by exposure to or recovery from MMA-SS fumes, the transcriptional changes of 13 genes that were highly altered by treatment were confirmed by quantitative real-time PCR. Notably, Mmp12, Cd5l, Ccl7, Cxcl5, and Spp1 related to the immune response were up-regulated only in the exposure group, whereas Trem2, IgG-2a, Igh-1a, and Igh were persistently up-regulated in both the exposure and recovery groups. In addition, several genes that might play a role in the repair process of the lung were up-regulated exclusively in the recovery group. Collectively, these data may help elucidate the molecular mechanism of the recovery process of the lung after welding fume exposure.Inhalation Toxicology 03/2009; 21(4):347-73. · 1.89 Impact Factor
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ABSTRACT: To identify changes in gene expression in the airways among welders, with and without lower airway symptoms, working in black steel. Included were 25 male, non-smoking welders. Each welder was sampled twice; before exposure (after vacation), and after 1 month of exposure. From the welders (14 symptomatic, of whom 7 had asthma-like symptoms), RNA from induced sputum was obtained for gene expression analysis. Messenger RNA from a subset of the samples (n = 7) was analysed with microarray technology to identify genes of interest. These genes were further analysed using quantitative PCR (qPCR; n = 22). By comparing samples before and after exposure, the microarray analysis resulted in several functional annotation clusters: the one with the highest enrichment score contained "response to wounding", "inflammatory response" and "defence response". Seven genes were analysed by qPCR: granulocyte colony-stimulating factor 3 receptor (CSF3R), superoxide dismutase 2, interleukin 8, glutathione S-transferase pi 1, tumour necrosis factor alpha-induced protein 6 (TNFAIP6), interleukin 1 receptor type II and matrix metallopeptidase 25 (MMP25). Increased levels of CSF3R, TNFAIP6 and MMP25 were indicated among asthmatic subjects compared to non-symptomatic subjects, although the differences did not reach significance. Workers' exposure to welding fumes changed gene expression in the lower airways in genes involved in inflammatory and defence response. Thus, microarray and qPCR technique can demonstrate markers of exposure to welding fumes and possible disease-related markers. However, further studies are needed to verify genes involved and to further characterise the mechanism for welding fumes-associated lower airway symptoms.International Archives of Occupational and Environmental Health 01/2011; 84(1):105-13. · 2.10 Impact Factor
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ABSTRACT: While early kidney development has been studied exhaustively, the later stages of nephrogenesis that occur after birth in the rodent are relatively poorly understood. To gain insight into this process, we detected the alterations in gene expression in rat kidney at two postnatal stages, P0 (0 day after birth), the time at which nephrogensis is still active, and P21 (21 days after birth), when nephrogenesis is complete. Sprague-Dawley rats were mated, and appearance of a vaginal plug was designated as E0. Kidneys were dissected from embryos at E13, E15, E17 and E19, and from postnatal days P0, P7, P14, P21 and adult rats. Suppression subtractive hybridization (SSH) analysis was performed and highly expressed genes were evaluated as molecular markers by real-time reverse transcription-polymerase chain reaction (RT-PCR), in situ hybridization, immunofluorescence, and Western blot. Several differentially expressed genes were identified, including rPEA3, a member of the PEA3 subfamily of Ets domain transcription factors. Real time RT-PCR analysis revealed that rPEA3 exhibited dynamic developmental regulation, with high levels of expression from embryonic day E15 until birth, and declining levels thereafter. By in situ hybridization, rPEA3 mRNA was detected in the ureteric bud (UB) and surrounding metanephric mesenchyme of the kidneys from E15 until birth, but was undetectable in mature kidneys. Double-immunofluorescence staining showed that both rPEA3 and WT1 expressed in the condensed mesenchymal cells at E15 and E17; and later from E19 to P7, both expressed in the epithelial cells of ureteric bud and their branches. These studies provide compelling evidence that SSH is an effective method for identifying genes that are regulated during renal development, and suggest that the newly identified gene rPEA3 may play an important role in kidney development and differentiation.Nephron Experimental Nephrology 02/2009; 111(4):e103-15. · 2.01 Impact Factor