Immune-inducible non-coding RNA molecule <i>lincRNA-IBIN</i> connects immunity and metabolism in <i>Drosophila melanogaster</i>

<div><p>Non-coding RNAs have important roles in regulating physiology, including immunity. Here, we performed transcriptome profiling of immune-responsive genes in <i>Drosophila melanogaster</i> during a Gram-positive bacterial infection, concentrating on long non-coding RNA (lncRNA) genes. The gene most highly induced by a <i>Micrococcus luteus</i> infection was <i>CR44404</i>, named <i>Induced by Infection</i> (<i>lincRNA-IBIN</i>). <i>lincRNA-IBIN</i> is induced by both Gram-positive and Gram-negative bacteria in <i>Drosophila</i> adults and parasitoid wasp <i>Leptopilina boulardi</i> in <i>Drosophila</i> larvae, as well as by the activation of the Toll or the Imd pathway in unchallenged flies. We show that upon infection, <i>lincRNA-IBIN</i> is expressed in the fat body, in hemocytes and in the gut, and its expression is regulated by NF-κB signaling and the chromatin modeling brahma complex. In the fat body, overexpression of <i>lincRNA-IBIN</i> affected the expression of Toll pathway -mediated genes. Notably, overexpression of <i>lincRNA-IBIN</i> in unchallenged flies elevated sugar levels in the hemolymph by enhancing the expression of genes important for glucose retrieval. These data show that lncRNA genes play a role in <i>Drosophila</i> immunity and indicate that <i>lincRNA-IBIN</i> acts as a link between innate immune responses and metabolism.</p></div>