Impaired iPLA2β activity affects iron uptake and storage without iron accumulation: An in vitro study excluding decreased iPLA2β activity as the cause of iron deposition in PLAN

Novel druggable mechanism of Parkinson's disease: Potential therapeutics and underlying pathogenesis based on ferroptosis

Genetics, age, environmental factors, and oxidative stress have all been implicated in the development of Parkinson's disease (PD); however, a complete understanding of its pathology remains elusive. At present, there is no cure for PD, and currently available therapeutics are insufficient to meet patient needs. Ferroptosis, a distinctive iron-dependent cell death mode characterized by lipid peroxidation and oxidative stress, has pathophysiological features similar to those of PD, including iron accumulation, reactive oxygen species-induced oxidative damage, and mitochondrial dysfunction. Ferroptosis has been identified as a specific pathway of neuronal death and is closely related to the pathogenesis of PD. Despite the similarities in the biological targets involved in PD pathogenesis and ferroptosis, the relationship between novel targets in PD and ferroptosis has been neglected in the literature. In this review, the mechanism of ferroptosis is discussed, and the potential therapeutic targets implicated in both PD and ferroptosis are compared. Furthermore, the anti-PD effects of several ferroptosis inhibitors, as well as clinical studies thereof, and the identification of novel lead compounds for the treatment of PD and the inhibition of ferroptosis are reviewed. It is hoped that this review can promote research to further elucidate the relationship between ferroptosis and PD and provide new strategies for the development of novel ferroptosis-targeting PD therapy.

Vitamin E prevents lipid peroxidation and iron accumulation in PLA2G6-Associated Neurodegeneration

BACKGROUND

PLA2G6-Associated Neurodegeneration (PLAN) is a rare neurodegenerative disease with autosomal recessive inheritance, which belongs to the NBIA (Neurodegeneration with Brain Iron Accumulation) group. Although the pathogenesis of the disease remains largely unclear, lipid peroxidation seems to play a central role in the pathogenesis. Currently, there is no cure for the disease.

OBJECTIVE

In this work, we examined the presence of lipid peroxidation, iron accumulation and mitochondrial dysfunction in two cellular models of PLAN, patients-derived fibroblasts and induced neurons, and assessed the effects of α-tocopherol (vitamin E) in correcting the pathophysiological alterations in PLAN cell cultures.

METHODS

Pathophysiological alterations were examined in fibroblasts and induced neurons generated by direct reprograming. Iron and lipofuscin accumulation were assessed using light and electron microscopy, as well as biochemical analysis techniques. Reactive Oxygen species production, lipid peroxidation and mitochondrial dysfunction were measured using specific fluorescent probes analysed by fluorescence microscopy and flow cytometry.

RESULTS

PLAN fibroblasts and induced neurons clearly showed increased lipid peroxidation, iron accumulation and altered mitochondrial membrane potential. All these pathological features were reverted with vitamin E treatment.

CONCLUSIONS

PLAN fibroblasts and induced neurons reproduce the main pathological alterations of the disease and provide useful tools for disease modelling. The main pathological alterations were corrected by Vitamin E supplementation in both models, suggesting that blocking lipid peroxidation progression is a critical therapeutic target.

Parkinson's disease and iron

While the initial causes of Parkinson's disease (PD) are not clearly defined, iron deposition has long been implicated in the pathogenesis of PD. The substantia nigra of PD patients, where the selective loss of dopaminergic neurons occurs, show a fairly selective and significant elevation in iron contents. However, the question remains whether iron deposition represents the initiation cause or merely the consequence of nigral degeneration. Here, we describe existing findings regarding the interaction of iron with neuromelanin and alpha synuclein, the iron deposition in experimental animal model of PD and sporadic and familial PD patients, and the treatment option involving the use of iron chelators for targeting the aberration of iron level in brain. This review may provide us a better understanding of the role of iron in PD to address the question of cause or consequence.

Early-Onset Parkinson's Disease Caused by PLA2G6 Compound Heterozygous Mutation, a Case Report and Literature Review

PLA2G6 has been certified as a causative gene in patients with autosomal recessive early-onset Parkinson's disease (EOPD). We reported an EOPD case caused by PLA2G6 gene mutation, and performed neurological examination, genetic analysis, and multimodal neuroimaging to describe this phenotype. A compound heterozygous mutation c.991G>T/c.1472+1G>A was detected in this patient. Heterozygous for the c.991G>T and c.1472+1G>A were separately detected in his parents. Pathogenicity of these two mutations were predicted according to the American college of medical genetics and genomics (ACMG) guideline. MRI assessment showed absence of bilateral “swallow tail sign” and cerebellar atrophy in this patient, while no obvious difference in brain iron accumulation between PLA2G6 mutant PD patient and healthy controls. Cerebellar abnormalities may be a marker for diagnosis and evaluation of PLA2G6 mutation Parkinsonism. However, the iron accumulation in PD may not be the result of PLA2G6 mutation.

Neurodegeneration with brain iron accumulation: Insights into the mitochondria dysregulation

NBIA (Neurodegeneration with brain iron accumulation) is a group of inherited neurologic disorders characterized by marked genetic heterogeneity, in which iron atypical accumulates in basal ganglia resulting in brain magnetic resonance imaging changes, histopathological abnormalities, and neuropsychiatric clinical symptoms. With the rapid development of high-throughput sequencing technologies, ten candidate genes have been identified, including PANK2, PLA2G6, C19orf12, WDR45, FA2H, ATP13A2, FTL, CP, C2orf37, and COASY. They are involved in seemingly unrelated cellular pathways, such as iron homeostasis (FTL, CP), lipid metabolism (PLA2G6, C19orf12, FA2H), Coenzyme A synthesis (PANK2, COASY), and autophagy (WDR45, ATP13A2). In particular, PANK2, COASY, PLA2G6, and C19orf12 are located on mitochondria, which associate with certain subtypes of NBIA showing mitochondria dysregulation. However, the relationships among those four genes are still unclear. Therefore, this review is specifically focused on dysregulation of mitochondria in NBIA and afore-mentioned four genes, with summaries of both pathological and clinical findings.