The lysosomal pathway: a new strategy in manganese-induced cell death

GOROJOD, R.M.;; ALAIMO A.; SAPIENZA C; KOTLER M.L.

Huerta Grande, Provincia de Córdoba, Argentina

Congreso; I Reunión Conjunta de Neurociencias (IRCN); 2009

Sociedad Argentina de Investigación en Neurociencias

Manganese (Mn) is an essential element for normal development and corporal function in mammals. However, overexposure to this metal produces accumulation mainly in astroglia, followed by permanent and progressive neurodegenerative damage. On the cellular level, lysosomes take up manganese to a greater extent than mitochondria, a fact that suggests that this organelles may play an important role in Mn metabolism and its toxicity. Citotoxicity of MnCl2 750µM in C6 glioma cells was assessed at different times. Cellular viability measured by mitochondrial dehydrogenases activity (MTT assay) diminished 6 ± 2% and 40 ± 2% for 6 and 24h treatment, respectively. When viability was assayed by neutral red staining, a vital dye that accumulates in lysosomes, a raise was measured for 6h (45 ± 4%) and a decrease (39% ± 4%) for 24h treatment. For this reason, lysosomes integrity was analized using acridine orange (AO) and an increase in positive cells to AO was found after a 6h Mn treatment (144 ± 28%). Using monodansylcadaverine, it was confirmed that changes on the lysosomal level were no due to autophagy induction. Bafilomycin A1 0,1nM, which is a lysosomal proton pump inhibitor and Pepstatine A 10µM, a Cathepsin D inhibitor, protected cells from Mn citotoxicity leading to a viability recovery of 21 ± 2% and 17 ± 2%, respectively. Therefore, our results suggest a role of lysosomal pathway in Mn-induced cell death in glioma C6 cells.