title: Low pH increases the yield of exosome isolation.
abstract: Exosomes are the extracellular vesicles secreted by various cells. Exosomes mediate intercellular communication by delivering a variety of molecules between cells. Cancer cell derived exosomes seem to be related with tumor progression and metastasis. Tumor microenvironment is thought to be acidic and this low pH controls exosome physiology, leading to tumor progression. Despite the importance of microenvironmental pH on exosome, most of exosome studies have been performed without regard to pH. Therefore, the difference of exosome stability and yield of isolation by different pH need to be studied. In this research, we investigated the yield of total exosomal protein and RNA after incubation in acidic, neutral and alkaline conditioned medium. Representative exosome markers were investigated by western blot after incubation of exosomes in different pH. As a result, the concentrations of exosomal protein and nucleic acid were significantly increased after incubation in the acidic medium compared with neutral medium. The higher levels of exosome markers including CD9, CD63 and HSP70 were observed after incubation in an acidic environment. On the other hand, no exosomal protein, exosomal RNA and exosome markers have been detected after incubation in an alkaline condition. In summary, our results indicate that the acidic condition is the favorable environment for existence and isolation of exosomes.
authors: Department of Bioscience and Biotechnology, College of Life Science, Institute of Biotechnology, Sejong University, Seoul, South Korea.
authors: Jae-Jun
authors: JJ
authors: Ban
authors: Department of Neurology, Seoul National University Hospital, Seoul, South Korea.
authors: Mijung
authors: M
authors: Lee
authors: Department of Neurology, Seoul National University Hospital, Seoul, South Korea. Electronic address: imwooseok@gmail.com.
authors: Wooseok
authors: W
authors: Im
authors: Department of Neurology, Seoul National University Hospital, Seoul, South Korea; Protein Metabolism Medical Research Center, College of Medicine, Seoul National University, Seoul, South Korea. Electronic address: kimmanho@snu.ac.kr.
authors: Manho
authors: M
authors: Kim
mesh_terms: D000818:Animals; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods*; D002458:Cell Fractionation / Q000379:methods*; D003470:Culture Media / Q000737:chemistry*; D055354:Exosomes / Q000737:chemistry* / Q000648:ultrastructure*; D057809:HEK293 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration
chemical_list: D003470:Culture Media
keywords: Acidic microenvironment; Exosome; pH