Accelerated capacity of glutamate uptake via blood elements as a possible tool of rapid remote conditioning mediated tissue protection

Abstract

Recently, the function of blood cells in remote ischemic conditioning (RIC) mediated neuroprotection was undoubtedly confirmed. In the present paper, we have focused on the role of blood elements in glutamate homeostasis. The blood of remote conditioned (tolerant) animals was incubated ex vivo with 100 μM glutamate, and the quantitative and qualitative changes of excitatory amino acid transporters (EAAT 1, 2, and 3) were determined. We confirmed RIC mediated accelerated sequestration of extracellular glutamate via EAATs and altered distribution of that amino acid between plasma and cell elements compared to non-tolerant counterparts. The activity of EAATs was elevated in erythrocytes and monocytes, while the density of transporters was not affected. Quantitative changes of EAAT1 density were detected solely in platelets where the forced scavenging was independent of EAATs inhibition. Surprisingly, the trafficking of immunovisualised EAAT2 and 3 raised at tolerant erythrocytes and monocytes. We have found that protein synthesis underlined this process. On the other hand, depletion of protein synthesis did not significantly affect the scavenging capacity of those cell populations. Our work has demonstrated that the elevated blood scavenging of glutamate overdose could be one of the potential mechanisms underlying RIC mediated tissue protection.