CONICET | Buscador de Institutos y Recursos Humanos

PRESENCE OF EXOSOMES CONTAINING THE AUTOPHAGY-RELATED PROTEIN VMP1 IN HUMAN SERUMMaria Noé Garcia1, Paula Sepúlveda Acuña1, Felipe Renna1, Tamara Orquera1, Lisandro Alle2, Sandra Muzietti3, Beatriz Caracciolo3, María Inés Vaccaro11Instituto de Biología y Medicina Molecular-Cátedra de Fisiopatología-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA). Buenos Aires, Argentina.2Departamento de Cirugía, División de Cirugía Digestiva, Hospital de Clínicas ?José de San Martín", UBA. Buenos Aires, Argentina.3Laboratorio de Gastroenterología y Enzimología Clínica, Departamento de Bioquímica Clínica, Facultad de Farmacia y Bioquímica, Hospital de Clínicas ?José de San Martin?, UBA. Buenos Aires, Argentina.VMP1 is a transmembrane protein that participates of the autophagic process. Overexpression of VMP1 induces autophagy even in full nutrient medium. VMP1 is induced in pancreas diseases such as pancreatitis and pancreas ductal adenocarcinoma (PDAC). Autophagy has been implicated in the endosome/exosome secretory pathway. Exosomes are small vesicles (40-120 nm) which are excreted by cells and mediate long distance cell communication. The objective of this work was to evaluate the presence of VMP1 in human serum. 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 transmembrane domains and is not a soluble protein, we hypothesize that its presence in serum is as a part of exosomes vesicles. Setting up two exosome purification protocols, by ultracentrifugation and by magnetic beads, we determined the presence of VMP1 in supernatant of different cell lines. Moreover, this presence was confirmed in the exosomal fraction, even under optimum nutrient conditions. Next, we purified exosomes from human serum and evidenced the presence of VMP1. In conclusion, we detected for the first time an autophagic protein in the extracellular compartment and in exosomes from human serum. These results suggest the importance of future research work exploring the relevance of VMP1 as biomarker for pancreas diseases.*This project has been approved by the Department of Clinical Research of the University Hospital.