Immune and stress response ‘cross-talk’ in the Drosophila Malpighian tubule

The success of insects is in large part due to their ability to survive environmental stress, including heat, cold, and dehydration. Insects are also exposed to infection, osmotic or oxidative stress, and to xenobiotics or toxins. The molecular mechanisms of stress sensing and response have been widely investigated in mammalian cell lines, and the area of stress research is now so vast to be beyond the scope of a single review article. However, the mechanisms by which stress inputs to the organism are sensed and integrated at the tissue and cellular level are less well understood. Increasingly, common molecular events between immune and other stress responses are observed invivo; and much of this work stems of efforts in insect molecular science and physiology. We describe here the current knowledge in the area of immune and stress signalling and response at the level of the organism, tissue and cell, focussing on a key epithelial tissue in insects, the Malpighian tubule, and drawing together the known pathways that modulate responses to different stress insults.The tubules are critical for insect survival and are increasingly implicated in responses to multiple and distinct stress inputs. Importantly, as tubule function is central to survival, they are potentially key targets for insect control, which will be facilitated by increased understanding of the complexities of stress signalling in the organism.

Summary of signalling mechanisms which modulate immune and stree sensing and response in the tubule principle cell. ← = stimulatory pathways;  = inhibitory pathways. Oxidative stress (Terhzaz et al., 2010a and Terhzaz et al., 2010b); immune stress (Overend et al., submitted for publication, Davies and Dow, 2009 and McGettigan et al., 2005); salt stress (Overend et al., 2012 and Stergiopoulos et al., 2009); desiccation stress (Terhzaz et al., in press).Figure optionsDownload as PowerPoint slideFigure optionsDownload as PowerPoint slideHighlights
► Understanding insect stress signaling is relevant to biomedicine and insect control.
► Epithelia sense and integrate multiple stress inputs, conferring organismal survival.
► Calcium and cyclic nucleotides modulate epithelial stress signaling.
► Innate immune and stress signaling transcriptional responses overlap.
► Key transcription factors play roles in both immune and stress responses.