title: Rat submandibular glands secrete nanovesicles with NTPDase and 5'-nucleotidase activities.
abstract: Extracellular nucleotides modulate a wide number of biological processes such as neurotransmission, platelet aggregation, muscle contraction, and epithelial secretion acting by the purinergic pathway. Nucleotidases as NTPDases and ecto-5'-nucleotidase are membrane-anchored proteins that regulate extracellular nucleotide concentrations. In a previous work, we have partially characterized an NTPDase-like activity expressed by rat submandibular gland microsomes, giving rise to the hypothesis that membrane NTPDases could be released into salivary ducts to regulate luminal nucleotide concentrations as was previously proposed for ovarian, prostatic, and pancreatic secretions. Present results show that rat submandibular glands incubated in vitro release membrane-associated NTPDase and ecto-5'-nucleotidase activities. Electron microscopy images show that released membranes presenting nucleotidase activity correspond to exosome-like vesicles which are also present at microsomal fraction. Both exosome release and nucleotidase activities are raised by adrenergic stimulation. Nucleotidase activities present the same kinetic characteristics than microsomal nucleotidase activity, corresponding mainly to the action of NTPDase2 and NTPDase3 isoforms as well as 5'-nucleotidase. This is consistent with Western blot analysis revealing the presence of these enzymes in the microsomal fraction.
authors.affiliation: Cátedra de Biofísica, Facultad de Odontología, Universidad de Buenos Aires, M. T. de Alvear 2142 (1122), Ciudad Autónoma de Buenos Aires, Argentina, debora@biofis.odon.uba.ar.
authors.forename: Débora A
authors.initials: DA
authors.lastname: González
authors.forename: Patricia
authors.initials: P
authors.lastname: Egido
authors.forename: Noelia B
authors.initials: NB
authors.lastname: Balcarcel
authors.forename: Claude
authors.initials: C
authors.lastname: Hattab
authors.forename: Martín M Barbieri
authors.initials: MM
authors.lastname: van Haaster
authors.forename: Julie
authors.initials: J
authors.lastname: Pelletier
authors.forename: Jean
authors.initials: J
authors.lastname: Sévigny
authors.forename: Mariano A
authors.initials: MA
authors.lastname: Ostuni
mesh_terms: D015720:5'-Nucleotidase / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D051381:Rats; D017208:Rats, Wistar; D022142:Secretory Vesicles / Q000201:enzymology*; D013363:Submandibular Gland / Q000201:enzymology / Q000378:metabolism*
chemical_list: D015720:5'-Nucleotidase; D000251:Adenosine Triphosphatases