Plasma Membrane Calcium Atpase downregulation in dopaminergic neurons alters cellular physiology and behavior in Drosophila melanogaster

Abstract

Accumulation of calcium is proposed to account for selective dopaminergic neuron (DN) dysfunctionality, a characteristic of Parkinsons Disease (PD). To test the in vivo impact of calcium increment in DN physiology we downregulated the Plasma Membrane Calcium ATPase (PMCA), a bomb that extrudes cytosolic calcium, in those neurons in Drosophila melanogaster. Using th-GAL4>PMCARNAi, PMCA was selectively reduced, leading to increased cytosolic calcium and mitochondrial oxidative stress with no neurodegeneration. In the eye, PMCARNAi expression provoked a subtle disorganization, suggesting scarce toxicity. Interestingly, we observed several locomotor alterations and a higher level of dopamine in brains. Finally, flies presented a reduction of lifespan and a perimortem non-motor phenotype characterized by abdominal swelling, possibly due to constipation. We conclude that elevated cytosolic calcium in DN could trigger cellular dysfunction generating mitochondrial oxidative stress and motor and non-motor symptoms, typical of PD.