P5-ATPase ATP13A2-overexpression in SH-SY5Y cells modifies the lipid homeostasis

MARCOS AL, SOLIS PAVESIO L, CORRADI GR, MAZZITELLI LR, ADAMO HP, DE TEZANOS

La plata

Congreso; Reunión Anual de la Sociedad Argentina de Biofísica; 2018

The  P-type  ion  pumps  are membrane transporters energizedby  ATP-hydrolysis.They were  classified into  five subfamilies termed P1-P5; the substrate specificity of P5 subfamily isstill  unknown. Five genes  named ATP13A1-ATP13A5 that belong tothe   P5-ATPases  are present  in humans.  Mutations  of  the   ATP13A2 gene,   also known as PARK9, were initially associated with  a form  of Parkinson?s Disease  (PD),a form  of NCL (CNL12)  and  of hereditary spastic paraplegia (SPG78)  ATP13A2  is localized  in  lysosomes  and  late   endosomes (LEs). Dysfunction  of  this   proteindiminishes  the   lysosomal degradation, the   autophagic flux and  the  exosome externalization. We have   previously  shown   that  ATP13A2 expression caused   a reduction  of   the   iron-induced  lysosome  membrane   permeabilization,   which suggests that  ATP13A2 overexpression improves the  lysosome and  LE membrane integrity.  In  this   work,  we  stably expressed the   ATP13A2 in SH-SY5Y humanneuroblastoma cell line.  By fluorescence microscopy, we found  that the expressionof            ATP13A2                 increases                the           accumulation         of             the   fluorescent    analog phosphatidylethanolamine (NBD-PE) while  reduces the  accumulation of  ceramide (NBD-ceramide). Inimmunofluorescence assays,  we  found  that  the  expressionof ATP13A2  reduces the content of bis(monoacylglyceryl)phosphate (BMP). Besides, the  triglyceride and cholesterol contentis  reduced in  ATP13A2-expressing cells,while  the  synthesis ofpolar  lipids  is increased. Altogether these  results show  that ATP13A2 overexpression modifies the lipid  homeostasis inSH-SY5Y cells.  As BMP is required for  the  lipid  degradation process  and  the  exosome biogenesis inside the acidic  compartments, these  results suggestthat  ATP13A2 may be modifying the lipid   digestion capacity and/or the   redistribution  of lipids   in  these  subcellularorganelles