PRESENCE OF EXOSOMES CONTAINING THE AUTOPHAGY-RELATED PROTEIN VMP1 IN HUMAN SERUM

FELIPE RENNA; TAMARA ORQUERA; MARÍA NOÉ GARCÍA; MARÍA INÉS VACCARO

CABA

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

SAIC, SAIB, SAI, SAA, SAB, SAB, SAFE, SAFIS, SAH, SAP

VMP1 is a transmembrane protein that participates of the autophagicprocess. Overexpression of VMP1 induces autophagy evenin full nutrient medium. VMP1 is induced in pancreas diseases such as pancreatitis and pancreas ductal adenocarcinoma (PDAC). Autophagyhas been implicated in the endosome/exosome secretorypathway. Exosomes are small vesicles (40-120 nm) which are excretedby cells and mediate long distance cell communication. Theobjective of this work was to evaluate the presence of VMP1 in humanserum. By western blot, and using three different antibodies,we were able to detect VMP1 in human serum samples* (N=20)from the University Hospital. Since VMP1 possess 6 transmembranedomains and is not a soluble protein, we hypothesize that itspresence in serum is as a part of exosomes vesicles. Setting up twoexosome purification protocols, by ultracentrifugation and by magneticbeads, we determined the presence of VMP1 in supernatantof different cell lines. Moreover, this presence was confirmed in theexosomal fraction, even under optimum nutrient conditions. Next,we purified exosomes from human serum and evidenced the presenceof VMP1. In conclusion, we detected for the first time an autophagicprotein in the extracellular compartment and in exosomesfrom human serum. These results suggest the importance of futureresearch work exploring the relevance of VMP1 as biomarker forpancreas diseases.