Exosome-like vesicles with dipeptidyl peptidase IV in human saliva.
Saliva contains a large number of proteins that participate in the protection of oral tissue. We found, for the first time, small vesicles (30-130 nm in diameter) in human whole saliva. Vesicles from saliva were identified by electron microscopy after isolation by gel-filtration on Sepharose CL-4B. They resemble exosomes, which are vesicles with an endosome-derived limiting membrane that are secreted by a diverse range of cell types. We performed a biochemical characterization of these vesicles by amino acid sequence analysis and Western blot analysis. We found that they contain dipeptidyl peptidase IV (DPP IV), galectin-3 and immunoglobulin A, which have potential to influence immune response. The DPP IV in the vesicles was metabolically active in cleaving substance P and glucose-dependent insulinotropic polypeptide to release N-terminal dipeptides. Our results demonstrate that human whole saliva contains exosome-like vesicles; they might participate in the catabolism of bioactive peptides and play a regulatory role in local immune defense in the oral cavity.
Ogawa
Yuko
Y
Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan.
Kanai-Azuma
Masami
M
Akimoto
Yoshihiro
Y
Kawakami
Hayato
H
Yanoshita
Ryohei
R
D000595:Amino Acid Sequence; D015153:Blotting, Western; D002850:Chromatography, Gel; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism*; D037502:Galectin 3 / Q000378:metabolism; D005749:Gastric Inhibitory Polypeptide / Q000378:metabolism; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D012463:Saliva / Q000201:enzymology*; D022142:Secretory Vesicles / Q000201:enzymology* / Q000648:ultrastructure; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013373:Substance P / Q000378:metabolism
D037502:Galectin 3; D007070:Immunoglobulin A; D013373:Substance P; D005749:Gastric Inhibitory Polypeptide; D018819:Dipeptidyl Peptidase 4