The main research interest of our group focuses on the study of how nutritional signals are detected by the organisms and which are the processes triggered in response to the nutritional status. One of the typical processes initiated by nutrition is reproduction. Females of the anautogenous species, some mosquito species as a paradigm, do not reproduce until they have taken a meal. This food intake will trigger a series of signals that will activate the physiological, metabolic or endocrine processes that lead to reproduction. The female of the German cockroach, Blattella germanica, is a typical anautogenous insect and a very good model of insect physiology because its reproduction is governed, as in most species, by juvenile hormone and not by ecdysteroids as it only happens in dipterans (flies and mosquitoes). During the last years, we have studied the functions of different proteins involved in nutritional signaling in B. germanica in relation to reproduction, but also to growth, stress resistance or longevity. One of the main tools that we use in our studies is RNA interference (RNAi) methodologies and, for this reason we are also interested in unveiling its mode of action.
The Insulin receptor pathway
Insulin/IGF-1 signaling (IIS) regulates key physiological processes in Metazoa: metabolism, growth, cell proliferation, reproduction, longevity or cancer. In vertebrates, insulin and IGFs regulate these processes by binding to Insulin and IGF-1 Receptors and the activation of their cellular signaling pathways. In insects, contrarily, a high number of Insulin-like Peptides (ILPs) bind to a single receptor. How do these peptides regulate the different processes in which they are involved if they bind to the same receptor? Are they functionally redundant or have specific functions? Answering this question will provided relevant information about a new mode of action of such an important signaling pathway.
RNAi mode of action
The RNA Interference (RNAi) methodology takes advantage of the mechanisms developed by the cells to defend themselves against the attack of harmful agents, such as certain types of viruses or transposons. Treatment with a dsRNA homologous to a given mRNA will specifically knock down this mRNA and, consequently, the encoded protein. In our lab, we are interested in understanding how RNAi works in insects for producing the RNA knock down effect. This study involves the analysis of the characteristics of the dsRNA molecules for producing the maximum effect, how Dicer or Argonaute enzymes contribute to the knock down and which intermediary molecules (small interfering RNAs) are more propitious to be produced. As the model molecule for RNAi treatment we are using the Insulin Receptor, for which we have already characterized the phenotype that its knock down produces.
Lab website: Maestro Lab
Ons, S.; Bellés, X.; Maestro, J. L. 2015. Orcokinins contribute to the regulation of vitellogenin transcription in the cockroach Blattella germanica. Journal of Insect Physiology 82: 129-133.
Süren-Castillo, S.; Abrisqueta, M.; and Maestro, J.L. 2014. FoxO is required for the activation of hypertrehalosemic hormone expression in cockroaches. Biochimica et Biophysica Acta 1840 (1):86-94