Cyclooxygenases and lipoxygenases: key players in the neuronal response to Maneb toxicity.

SALVADOR, G.; ALZA, N.P.; BENZI JUNCOS, O.N.

Virtual

Congreso; SAIB - SAMIGE Joint meeting 2021 on line; 2021

Maneb (MB) is a widely used fungicide for plague control in a variety of crops. The prolonged use causes human toxicity, especially in the Central Nervous System, and it is considered an environmental risk factor for Parkinson?s disease. However, the mechanisms underlying pesticide neurotoxicity are not completely elucidated. Based on this, we studied the effect of MB toxicity on lipid mediators? pathways in dopaminergic neurons (N27 cell line) as well as in glial cells (C6 astrocytes cell line).MB treatment affected neuronal and glial viability in a time- and concentration-dependent manner. To characterize the cellular response to MB, we analyzed the expression and subcellular localization of the transcription factor NF-κB and its downstream gene cyclooxygenase-2 (COX-2). The increased expression and nuclear translocation of NF-κB p50 subunit was associated with a rise in COX-2 levels in MB-exposed neurons. Astrocytes treated with MB showed increased GFAP, NF-κB p50 and COX-2 expression, indicative markers of glial activation. Interestingly, MB only triggered the nuclear translocation of COX-2 in neurons. To further elucidate the role of COX-2 in MB toxicity, cells were treated with pharmacological and suicidal enzymatic inhibitors, celecoxib and acetylsalicylic acid (ASA), respectively. Neurons incubated with celecoxib were more sensitive than astrocytes to MB exposure. Surprisingly, COX-2 acetylation by ASA turned neurons and astrocytes more vulnerable to MB toxicity. Given that COX-2 acetylation not only inhibits prostaglandin synthesis but also enhances the production of specialized pro-resolving lipid mediators (SPMs), these findings indicate that, probably, prostaglandins derived from arachidonic acid are protective against MB toxicity and ASA-triggered lipid mediator pathways might be involved as promoters of pesticide-induced neuronal injury. To shed light on the interplay between prostaglandins and SPMs producing pathways, the effect of cytochrome P450 and lipoxygenase-15 (LOX-15) inhibition was also evaluated. The inhibition of both pathways separately enhanced MB toxicity and this effect was potentiated by ASA treatment. To investigate neuron-glia crosstalk during MB toxicity, N27 cells were incubated with C6 secretome and vice versa. Astrocytes secretome showed to be protective for neurons challenged with MB. In addition, neurons secreted glial proliferative factors after MB exposure. Our results demonstrate the interplay among COX-2, LOX-15 and cytochrome P450 in SPMs production during MB exposure. Moreover, cell type-specific responses are indicative of particular roles of neurons and glia in the protective mechanisms against pesticide toxicity