In vivo ferroptosis induces lipid cacostasis: implications for neurodegeneration associated with parkinson´s disease

Abstract

Ferroptosis is a recently discovered type of cell death that results from iron (Fe)‐dependent lipid peroxide accumulation and has been proposed as one of the main mechanisms responsible for neuronal death in Parkinson´s disease (PD). In this connection, Fe accumulation in several brain regions, and specifically in the substantia nigra has been reported in PD patients. We have previously demonstrated that dopaminergic neurons exposed to α-synuclein overexpression and Fe overload display lipid dyshomeostasis that results in triacylglycerol accumulation and exacerbated phospholipid hydrolysis. In this work, our goal was to characterize the brain lipid profile in an in vivo model of ferroptosis. For this purpose, C57BL/6 mice were subjected to Fe overload by performing a four-doses scheme of intraperitoneal administration (Fe-saccharate -800 or 1332 mg/kg- or vehicle). During treatment (16 days), animal welfare and locomotor activity were periodically evaluated. After sacrifice, biochemical parameters were determined in several organs (brain, liver and kidney). Motor skills were assessed by using open field and footprint tests. Mice exposed to Fe overload (1332 mg/kg) showed a 60% diminution of total distance traveled, associated with a greater thigmotaxis (20%; p <0.05) and a slightly delayed right footprint. These alterations in motor skills were related to increased α-synuclein expression. A buildup of oxidative stress markers associated with ferroptosis, such as lipid peroxide levels and conjugated dienes and trienes products derived from fatty acid oxidation (200% and 500%, respectively), was detected in the brain of Fe-treated animals compared to controls (p<0.001). Liver and kidney presented a similar profile of oxidative stress markers. Brain lipid content was altered in Fe-treated mice. Whereas increased cholesterol (p< 0.05) and diacylglycerol (p<0.001) levels were detected, their acylated forms were decreased (p<0.05). Total brain phospholipid levels remained unaltered in the ferroptosis model. Changes in neutral lipid profile were paradoxically associated with diminished expression of lipases such as calcium-independent phospholipase A2 and adipose-triacylglycerol lipase. Our results demonstrate that lipid cacostasis is associated with brain Fe accumulation, ferroptosis and motor impairment. The imbalance in lipid acylation/deacylation processes and cholesterol accumulation reported here could be considered as biomarkers of Fe-induced neurodegeneration and ferroptosis.