engleski

A screening of an organophosphate’s effect on the plasma membrane organization of the mouse brain

Organophosphates (OPs) such as nerve agents are lipophilic molecules that inhibit the enzyme acetylcholinesterase (AChE), which has an essential role in hydrolysing the neurotransmitter acetylcholine. The inhibition of AChE leads to the onset of life­threatening symptoms induced by the overstimulation of nicotinic and muscarinic receptors, which can result in death. Oxime compounds are used for reactivation of inhibited AChE, but there is no universal therapy for exposure to different OPs. Moreover, the effect of the OPs is not limited to cholinergic functions but affects neuritogenesis, cell­cell interactions, apoptosis, synaptogenesis, amyloid fibre formation, and they possess membrane disrupting potential due to their lipophilicity. The compartmentalization of the plasma membrane into lipid rafts has an important role in cellular signalling, endocytosis, exocytosis, and other cellular processes. Lipid raft (LR) disruption can lead to apoptosis, disorders in regulation of neurotransmission and protein trafficking, and is associated with several diseases. Herein, we investigated whether an OP induces the reorganization of the membrane subdomains. Mice exposed to a sub­lethal dose of nerve agent were compared to mice treated with an oxime 30 minutes after OP and both groups compared to control mice without any treatment. Mice were sacrificed 1.5h, 2 and 4 days after OP administration, brains were dissected and snap­frozen. LR were isolated from brain cortices by ultracentrifugation in discontinuous sucrose gradients and Western blotting was performed for LR markers ganglioside GM1 and Flotillin­1, and non­lipid raft marker transferrin receptor. The results showed that there were slight disturbances in the distribution of the markers with regard to the OP exposure and therapy when compared to control mice, which makes this a promising base for further investigation.

organophosphate ; plasma membrane ; lipid raft ; ganglioside GM1 ; flotillin-1 ; transferrin receptor

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