engleski

The expression of neuroplastin, calcium ATPase and sodium/potassium ATPase in the brain of mice lacking Toll-like receptor 2

Toll-like receptors (TLRs) are widely expressed in mammalian brain. Involvement in neurodegeneration and hypoxia has been evidenced for several microglial TLRs. In order to investigate interplay of specific microglial and neuronal transmembrane proteins and its potential role in neurodegeneration, we use TLR2 knock-out (KO ) mice (C57BL/6 TLR2-/-).Our preliminary findings indicate different expression of synaptic transmembrane protein neuroplastin (Np) in brain tissue of TLR2 KO mice in comparison with wild- type littermates (WT).Neuroplastin, a cell- adhesion molecule found in two isoforms (Np65 and Np55) is an essential auxiliary subunit of plasma membrane Ca2+ ATPase (PMCA ). In addition, Np is influenced by glycosphingolipid environment of the membrane, which is also the case for another ion pumping enzyme, Na+/K+-ATPase (NKA). Since Np, PMCA and NKA all seem to favor specific lipid milieu in order to function optimally, and at least some of them are confirmed to interact with one another, we investigated the expression of these proteins in TLR2 KO compared to WT across different brain regions.We isolated membrane fractions from cortical, hippocampal and cerebellar tissue of 5 WT and 5 KO animals, and analyzed the expression of Np, NKA and PMCA by Western blotting. Data revealed increased expression level of Np isoforms and PMCA in cortex and hippocampus in TLR2 KO, and decreased expression of Np55 and PMCA in the cerebellum. NKA exhibited the same expression pattern in TLR2 KO vs WT, and increased expression in all regions analyzed (cortex, hippocampus, cerebellum). Furthermore, we investigated the cortical NKA activity which is lower in TLR2 KO mice.This data together with ongoing immunohistochemistry and transcriptional analysis will enable more detailed neurobiochemical characterization of TLR2 KO model, and give insight into functional implications of differential regional distribution of here analyzed proteins involved in synaptic plasticity and membrane ion transport.

mouse brain ; toll-like receptors ; neuroplastin

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