Lipid droplets populations in the insect vector of Chagas Disease (Triatoma infestans)

JUAN R. GIROTTI; DELFINA L. BORUS; NATALIA S. SCELCIO; NICOLÁS O. FAVALE; ANA VES-LOSADA

Salta

Congreso; Joint LV Annual SAIB Meeting and XIV PABMB Congress; 2019

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

The objective of the work was to characterize populations of Lipid Droplets in Triatoma infestans (vinchuca). The insect is one the main vectorof the parasite Trypanosoma cruzi, the causative agent of Chagas disease in Argentina and the Americas. The cuticle (C) is the insect mostexternal structure, which protects against physical, chemical (dehydration, etc.) and biological (infections, etc.) external factors. Oenocyte cells(OE) are involved in the anabolism of C hydrophobic molecules (hydrocarbons, alcohols, waxes, glycerides, fatty acids, etc). The fat body (FB)is the organ that regulates the entire insect metabolism. The information on the lipid metabolism of the insect will allow the acquisition of newtools to control the vector. Taking into account the scarce information on OE from C in Triatoma infestans, the aim of the work was to identifypossible populations of LD in these cells as organoids involved in the genesis of C. Previously we demonstrated that in liver, LD populations aredynamic organelle where neutral lipids are stored, mainly located in the cytosol (cLD) and in a small proportion in the nucleus (nLD). For thispurpose, protocols were developed to identify and characterize LD populations in FB samples, whole cuticle (C) and scraping of the epidermis(E) of insects fast or feed. Light field microscopy and fluorescence (epifluorescence and confocal) and hematoxylin / Oil Red and DAPY /BODYPY stains were used, respectively. In all the samples studied, populations of LD were observed in the cytosol (cLD). The FB has animportant population of cLD characterized by large LD; while the cuticle (C and E), and in particular in OE cells, the population of cLD that islarge, is made up of LD of smaller size than those of FB. In OE the main LD population is located in the cytosol and a small population withinthe cell nucleus (nLD). These results would confirm the role assigned to OE to actively participate in the anabolism of the cuticle components,moreover, small LDs are metabolically more active than larger LD. In conclusion, Triatoma infestans cuticular oenocytes were characterized ascells that have a very varied morphology, depending on the development state of the insect, and are larger than the surrounding epithelial cells.The OEs have two LD populations, a main cytosolic and a nuclear one. These are the first results where nLDs are described in insects.