Anastasia Khutornenko1, Anastasia Zharikova2, Vasily Popkov3, Sergey Kovalchuk4, Kirill Goryunov5, Yulia Shevtsova6, Egor Plotnikov7, Dmitry Zorov8, Denis Silachev91Laboratory of Cell Technologies, Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia, bioingenier@gmail.com2Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia, azharikova89@gmail.com3The A.N. Belozersky Institute Of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia, popkov.vas@gmail.com4Laboratory of Bioinformatic methods for Combinatorial Chemistry and Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, xerx222@gmail.com5Laboratory of Cell Technologies, Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia, kirishgor@gmail.com6Laboratory of Cell Technologies, Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia, yulshevtsova@yandex.ru7A.N. Belozersky Institute of Physico-Chemical Biology; Research Center of Obstetrics, Gynecology and Perinatology, Moscow, Russia, plotnikov@belozersky.msu.ru8A.N. Belozersky Institute of Physico-Chemical Biology; Reserch Center of Obstetrics, Gynecology and Perinatology, Moscow, Russia, zorov@belozersky.msu.ru9A.N. Belozersky Institute of Physico-Chemical Biology; Research Center of Obstetrics, Gynecology and Perinatology, Moscow, Russia, d_silachev@oparina4.ru Mesenchymal stem/stromal cells (MSCs) have therapeutic potential in many pathological conditions, that is explained mostly by their paracrine action. MSCs secrete extracellular vesicles (EVs) packed with proteins, DNA, RNA and lipids. One of the easily accessible and reach sources of MSCs is placenta. In order to reveal possible pathways, by which EVs produced by placenta-derived MSCs (EVs-PMSC) could realize their therapeutic potential we conducted proteomic analysis of EVs-PMSC and subsequent bioinformatic analysis of identified proteins using Reactome pathway database. Identified peptides were mapped to 2093 proteins. Among the 2093 proteins, 972 proteins were identified in at least four LC-MS/MS analyses out of eight. According to Reactome the most significant ‘top three’ 1st level pathways for detected EVs-PMSC proteins were ‘Cellular responses to external stimuli’; ‘Immune system’; ‘Developmental biology’. Some of the most enriched pathways in the group ‘Cellular responses to external stimuli’ were: ‘Response of EIF2AK4 (GCN2) to amino acid deficiency’; ‘Cellular response to hypoxia’; ‘Detoxification of Reactive Oxygen Species’. Some of the most enriched pathways in the group ‘Immune System’ were: ‘Class I MHC mediated antigen processing & presentation’; ‘Neutrophil degranulation’; ‘Interferon Signaling’. The most enriched pathway in the group ‘Developmental biology’ was ‘Axon guidance’. Thus far, concerning most enriched pathways EVs-PMSC proteome is expected to: 1) provide protection against stress (amino acid deficiency, hypoxia, ROS) to the damaged tissues; 2) possess immunomodulation properties; 3) facilitate axon guidance. The result (the top list of enriched pathways) leads to the notion that EVs-PMSC could be effective in terms of neuroprotection.