Neuroprotection is one of the prominent functions of the interleukin (IL)-6-type cytokine family, for which the underlying mechanism(s) are not fully understood. We have previously shown that neuroprotection and neuromodulation mediated by IL-6 require neuronal adenosine A1 receptor (A 1R) function. We now have investigated whether two other IL-6-type cytokines [oncostatin M (OSM) and leukemia inhibitory factor (LIF)] use a similar mechanism. It is presented here that OSM but not LIF, enhanced the expression of A1Rs (both mRNA and protein levels) in cultured neurons. Whereas the neuroprotective effect of LIF was unchanged in A 1R deficient neurons, OSM failed to protect neurons in the absence of A1R. In addition, OSM pre-treatment for 4 h potentiated the A 1R-mediated inhibition of electrically evoked excitatory post-synaptic currents recorded from hippocampal slices either under normal or hypoxic conditions. No such effect was observed after LIF pre-treatment. Our findings thus strongly suggest that, despite known structural and functional similarities, OSM and LIF use different mechanisms to achieve neuroprotection and neuromodulation.
- leukemia inhibitory factor
- oncostatin M