Chronic activation of the epithelial immune system of the fruit fly's salivary glands has a negative effect on organismal growth and induces a peculiar set of target genes

BMC Genomics

Research Article

Thomas Roeder¹  Ahmed Abdelsadik² 

[1] Christian-Albrechts-University of Kiel, Zoophysiology, Olshausenstraße 40, D-24098, Kiel, Germany;Forschungszentrum Borstel, Dept. Immunology and Cell Biology, Parkallee 1-40, 23845, Borstel, Germany;Christian-Albrechts-University of Kiel, Zoophysiology, Olshausenstraße 40, D-24098, Kiel, Germany;Zoology Department, Faculty of Science at Aswan, South Valley University of Aswan, 81528, Aswan BranchAswan, Egypt;

关键词: Salivary Gland;    Antimicrobial Peptide;    Downregulated Gene;    Autophagic Cell Death;    Ectopic Activation;   

DOI  :  10.1186/1471-2164-11-265

 received in 2009-11-03, accepted in 2010-04-26,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundEpithelial and especially mucosal immunity represents the first line of defence against the plethora of potential pathogens trying to invade via the gastrointestinal tract. The salivary glands of the fruit fly are an indispensable part of the gastrointestinal tract, but their contribution to the mucosal immunity has almost completely been neglected. Our major goal was to elucidate if the fly's salivary glands are able to mount an immune response and what the major characteristics of this immune response are.ResultsEctopic activation of the IMD-pathway within the salivary gland cells is able to induce an immune response, indicating that the salivary glands are indeed immune competent. This reaction is characterized by the concurrent expression of numerous antimicrobial peptide genes. In addition, ectopic activation of the salivary gland's immune response induces morphological changes such as dwarfism throughout all developmental stages and a significantly decreased length of the salivary glands themselves. DNA-microarray analyses of the reaction revealed a complex pattern of up- and downregulated genes. Gene ontology analyses of regulated genes revealed a significant increase in genes associated with ribosomal and proteasomal function. On the other hand, genes coding for peptide receptors and some potassium channels are downregulated. In addition, the comparison of the transcriptional events induced following IMD-activation in the trachea and the salivary glands shows also only a small overlap, indicating that the general IMD-activated core transcriptome is rather small and that the tissue specific component of this response is dominating. Among the regulated genes, those that code for signaling associated protease activity are significantly modulated.ConclusionsThe salivary glands are immune-competent and they contribute to the overall intestinal immune system. Although they produce antimicrobial peptides, their overall response is highly tissue-specific. Our analysis indicates that chronic activation of the salivary gland's immune system is costly, as it induces severe reduction in growth throughout development. The IMD-regulated increase in expression levels of the fly's presenilin representatives opens the opportunity to use the salivary glands for studying the physiological and pathophysiological role of these genes in a simple but functional environment.

【 授权许可】

CC BY   
© Abdelsadik and Roeder; licensee BioMed Central Ltd. 2010