Antithrombin is incorporated into exosomes produced by antithrombin non-expressing cells

• Published in: Biochimie Vol. 165; pp. 245 - 249
• Main Authors: Luengo-Gil, Ginés, García-Andreo, Antonio Bernardino, Ortega-Sabater, Carmen, Bohdan, Nataliya, Espín, Salvador, Peñas-Martínez, Julia, Martínez-Planes, Elena, García-Hernández, Álvaro, Vicente, Vicente, Quintanilla, Miguel, Martínez-Martínez, Irene
• Format: Journal Article
• Language: English
• Published: France Elsevier B.V 01.10.2019
• Subjects: Animals; Antithrombin; Antithrombins - metabolism; Blood Coagulation - physiology; Dogs; Exosomes; Exosomes - metabolism; Heparin - chemistry; High-Temperature Requirement A Serine Peptidase 1 - metabolism; HTRA1; Madin Darby Canine Kidney Cells; MDCK cells; LMWH; MDCK cells; UPR; HTRA1; MDCK; Exosomes; Antithrombin
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/j.biochi.2019.08.010

Antithrombin is a serine protease inhibitor that exerts a crucial role in hemostasis as the main inhibitor of the coagulation cascade. It plays also critical roles in other processes, such as inflammation and cancer. Here we show that exosomes released by Madin-Darby canine kidney (MDCK) cells cultured in the presence of heparin incorporate antithrombin from the serum. Exosomal antithrombin is found complexed with the serine protease high temperature requirement A1 (HTRA1), whose cellular levels are increased after serum deprival, the condition used to collect exosomes. Although the biological relevance of the presence of antithrombin in exosomes remains to be investigated, our results suggest a functional interplay between antithrombin and HTRA1. •Antithrombin is found in exosomes released by cells that do not express antithrombin.•A fraction of antithrombin binds covalently HTRA1 on the surface of exosomes.•Deprival of serum induces HTRA1 overexpression as a result of the UPR response.