Stability of human salivary extracellular vesicles containing dipeptidyl peptidase IV under simulated gastrointestinal tract conditions

Yuko Ogawa; Yoshihiro Akimoto; Mamoru Ikemoto; Yoshikuni Goto; Anna Ishikawa; Sakura Ohta; Yumi Takase; Hayato Kawakami; Masafumi Tsujimoto; Ryohei Yanoshita

doi:10.1016/j.bbrep.2021.101034

Stability of human salivary extracellular vesicles containing dipeptidyl peptidase IV under simulated gastrointestinal tract conditions

Biochem Biophys Rep. 2021 Jun 3:27:101034. doi: 10.1016/j.bbrep.2021.101034. eCollection 2021 Sep.

Affiliations

¹ Faculty of Pharmaceutical Sciences, Teikyo Heisei University, 4-21-2 Nakano, Nakano-ku, Tokyo, 164-8530, Japan.
² Department of Anatomy, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.

Abstract

Background: Extracellular vesicles (EVs) have been isolated from various sources, including primary and cultured cell lines and body fluids. Previous studies, including those conducted in our laboratory, have reported the stability of EVs under various storage conditions.

Methods: EVs from human whole saliva were separated via size-exclusion chromatography. To simulate the effects of gastric or intestinal fluids on the stability of EVs, pepsin or pancreatin was added to the samples. Additionally, to determine the effect of bile acids, sodium cholate was added. The samples were then subjected to western blotting, dynamic light scattering, and transmission electron microscopy analyses. In addition, the activity of dipeptidyl peptidase (DPP) IV retained in the samples was examined to monitor the stability of EVs.

Results: Under acidic conditions, with pepsin mimicking the milieu of the stomach, the EVs remained stable. However, they partially lost their membrane integrity in the presence of pancreatin and sodium cholate, indicating that they may be destabilized after passing through the duodenum. Although several associated proteins, such as mucin 5B and CD9 were degraded, DPP IV was stable, and its activity was retained under the simulated gastrointestinal conditions.

Conclusion: Our data indicate that although EVs can pass through the stomach without undergoing significant damage, they may be disrupted in the intestine to release their contents. The consistent delivery of active components such as DPP IV from EVs into the intestine might play a role in the efficient modulation of homeostasis of the signal transduction pathways occurring in the gastrointestinal tract.

Keywords: Alix, programmed cell death 6-interacting protein; DLS, dynamic light scattering; DPP IV, dipeptidyl peptidase IV; Dipeptidyl peptidase IV; EVs, extracellular vesicles; Exosomes; Extracellular vesicles; Gastrointestinal condition; Human whole saliva; MCA, 4-methyl-coumaryl-7-amide; PBS, phosphate buffered saline; PLA2, phospholipase A2; SD, standard deviation; Stability; TEM, transmission electron microscopic; TSG101, tumor susceptibility gene 101; WS, whole saliva.