OBJECTIVE: Microvesicles (MVs) have been indicated as important mediators of intercellular communication and are emerging as new biomarkers of tissue damage. Our previous data indicate that reactive microglia/macrophages release MVs in vitro. The aim of the study was to evaluate whether MVs are released by microglia/macrophages in vivo and whether their number varies in brain inflammatory conditions, such as multiple sclerosis (MS). METHODS: Electron and fluorescence microscopy and flow cytometry were used to detect myeloid MVs in the cerebrospinal fluid (CSF) of healthy controls, MS patients, and rodents affected by experimental autoimmune encephalomyelitis (EAE), the animal model of MS. RESULTS: Myeloid MVs were detected in CSF of healthy controls. In relapsing and remitting EAE mice, the concentration of myeloid MVs in the CSF was significantly increased and closely associated with disease course. Analysis of MVs in the CSF of 28 relapsing patients and 28 patients with clinical isolated syndrome from 2 independent cohorts revealed higher levels of myeloid MVs than in 13 age-matched controls, indicating a clinical value of MVs as a companion tool to capture disease activity. Myeloid MVs were found to spread inflammatory signals both in vitro and in vivo at the site of administration; mice impaired in MV shedding were protected from EAE, suggesting a pathogenic role for MVs in the disease. Finally, FTY720, the first approved oral MS drug, significantly reduced the amount of MVs in the CSF of EAE-treated mice. INTERPRETATION: These findings identify myeloid MVs as a marker and therapeutic target of brain inflammation.
OBJECTIVE: Microvesicles (MVs) have been indicated as important mediators of intercellular communication and are emerging as new biomarkers of tissue damage. Our previous data indicate that reactive microglia/macrophages release MVs in vitro. The aim of the study was to evaluate whether MVs are released by microglia/macrophages in vivo and whether their number varies in brain inflammatory conditions, such as multiple sclerosis (MS). METHODS: Electron and fluorescence microscopy and flow cytometry were used to detect myeloid MVs in the cerebrospinal fluid (CSF) of healthy controls, MS patients, and rodents affected by experimental autoimmune encephalomyelitis (EAE), the animal model of MS. RESULTS: Myeloid MVs were detected in CSF of healthy controls. In relapsing and remitting EAE mice, the concentration of myeloid MVs in the CSF was significantly increased and closely associated with disease course. Analysis of MVs in the CSF of 28 relapsing patients and 28 patients with clinical isolated syndrome from 2 independent cohorts revealed higher levels of myeloid MVs than in 13 age-matched controls, indicating a clinical value of MVs as a companion tool to capture disease activity. Myeloid MVs were found to spread inflammatory signals both in vitro and in vivo at the site of administration; mice impaired in MV shedding were protected from EAE, suggesting a pathogenic role for MVs in the disease. Finally, FTY720, the first approved oral MS drug, significantly reduced the amount of MVs in the CSF of EAE-treated mice. INTERPRETATION: These findings identify myeloid MVs as a marker and therapeutic target of brain inflammation.
Authors: María Yáñez-Mó; Pia R-M Siljander; Zoraida Andreu; Apolonija Bedina Zavec; Francesc E Borràs; Edit I Buzas; Krisztina Buzas; Enriqueta Casal; Francesco Cappello; Joana Carvalho; Eva Colás; Anabela Cordeiro-da Silva; Stefano Fais; Juan M Falcon-Perez; Irene M Ghobrial; Bernd Giebel; Mario Gimona; Michael Graner; Ihsan Gursel; Mayda Gursel; Niels H H Heegaard; An Hendrix; Peter Kierulf; Katsutoshi Kokubun; Maja Kosanovic; Veronika Kralj-Iglic; Eva-Maria Krämer-Albers; Saara Laitinen; Cecilia Lässer; Thomas Lener; Erzsébet Ligeti; Aija Linē; Georg Lipps; Alicia Llorente; Jan Lötvall; Mateja Manček-Keber; Antonio Marcilla; Maria Mittelbrunn; Irina Nazarenko; Esther N M Nolte-'t Hoen; Tuula A Nyman; Lorraine O'Driscoll; Mireia Olivan; Carla Oliveira; Éva Pállinger; Hernando A Del Portillo; Jaume Reventós; Marina Rigau; Eva Rohde; Marei Sammar; Francisco Sánchez-Madrid; N Santarém; Katharina Schallmoser; Marie Stampe Ostenfeld; Willem Stoorvogel; Roman Stukelj; Susanne G Van der Grein; M Helena Vasconcelos; Marca H M Wauben; Olivier De Wever Journal: J Extracell Vesicles Date: 2015-05-14