Ferroptosis-Regulated Cell Death as a Therapeutic Strategy for Neurodegenerative Diseases: Current Status and Future Prospects

Exploring the association between aging, ferroptosis, and common age-related diseases

Aging is a natural biological process that is characterized by the progressive decline in physiological functions and an increased vulnerability to age-related diseases. The aging process is driven by different cell and molecular mechanisms. It has recently been shown that aging is associated with heightened vulnerability to ferroptosis (an intracellular iron-dependent form of programmed cell death). This susceptibility arises from various factors including oxidative stress, impaired antioxidant defences, and dysregulated iron homeostasis. The progressive decline in cellular antioxidant capacity and the accumulation of damaged components contribute to the increased susceptibility of aging cells to ferroptosis. Dysregulation of key regulators involved in ferroptosis, such as glutathione peroxidase 4 (GPX4), iron regulatory proteins, and lipid metabolism enzymes, further exacerbates this vulnerability. The decline in cellular defence mechanisms against ferroptosis during aging contributes to the accumulation of damaged cells and tissues, ultimately resulting in the manifestation of age-related diseases. Understanding the intricate relevance between aging and ferroptosis holds significant potential for developing strategies to counteract the detrimental effects of aging and age-related diseases. This will subsequently act to mitigate the negative consequences of aging and improving overall health in the elderly population. This review aims to clarify the relationship between aging and ferroptosis, and explores the underlying mechanisms and implications for age-related disorders, including neurodegenerative, cardiovascular, and neoplastic diseases. We also discuss the accumulating evidence suggesting that the imbalance of redox homeostasis and perturbations in iron metabolism contribute to the age-associated vulnerability to ferroptosis.

Anti-Alzheimer effects of an HDAC6 inhibitor, WY118, alone and in combination of lithium chloride: Synergistic suppression of ferroptosis via the modulation of tau phosphorylation and MAPK signaling

Alzheimer's disease (AD) is a complex neurodegenerative disorder, and current therapies mainly offer symptomatic relief. Given that the pathophysiology of AD is multifaceted, a multimodal therapeutic strategy targeting multiple molecular pathways implicated in AD-related pathogenesis represents a pragmatic avenue for impeding the advancement of AD. In this study, we evaluated the anti-Alzheimer effects of an HDAC6 inhibitor WY118, both alone and in combination with lithium chloride (LiCl), a GSK-3β inhibitor, to synergistically suppress ferroptosis. The combination of compound WY118 and LiCl demonstrated significant synergistic effects in both cellular models of AD induced by glutamate and streptozotocin. The findings suggest that compound WY118, in particular in combination with LiCl, exhibits potent anti-Alzheimer effects by synergistically suppressing ferroptosis. Studies on the mechanism of action indicated that the combination treatment significantly reduced tau phosphorylation and inhibited p38 MAPK signaling. This combination therapy holds promise for developing more effective treatments for AD.

The key role of the ferroptosis mechanism in neurological diseases and prospects for targeted therapy

Neurological disorders represent a major global health concern owing to their intricate pathological processes. Ferroptosis, defined as a form of cell death that is reliant on iron, has been closely linked to various neurological conditions. The fundamental process underlying ferroptosis is defined by the excessive buildup of iron ions, which initiates lipid peroxidation processes leading to cellular demise. Neurons, as highly metabolically active cells, are susceptible to oxidative stress, and imbalances in iron metabolism can directly initiate the ferroptosis process. In neurodegenerative disorders like Alzheimer's disease and Parkinson's disease, ferroptosis driven by iron accumulation represents a fundamental pathological connection. Although the connection between ferroptosis and neurological diseases is clear, clinical application still faces challenges, such as precise regulation of iron metabolism, development of specific drugs, and assessment of efficacy. The limited comprehension of the ferroptosis mechanism hinders the development of personalized treatment approaches. Consequently, subsequent investigations must tackle these obstacles to facilitate the clinical application of ferroptosis-associated therapies in neurological disorders. This article provides a comprehensive overview of the most recent advancements regarding the underlying mechanisms of ferroptosis. Subsequently, the study investigates the mechanistic contributions of ferroptosis within the nervous system. In conclusion, we evaluate and deliberate on targeted therapeutic strategies associated with ferroptosis and neurological disorders.

The role of microglia in neurodegenerative diseases: from the perspective of ferroptosis

Iron plays a pivotal role in numerous fundamental biological processes in the brain. Among the various cell types in the central nervous system, microglia are recognized as the most proficient cells in accumulating and storing iron. Nonetheless, iron overload can induce inflammatory phenotype of microglia, leading to the production of proinflammatory cytokines and contributing to neurodegeneration. A growing body of evidence shows that disturbances in iron homeostasis in microglia is associated with a range of neurodegenerative disorders. Recent research has revealed that microglia are highly sensitive to ferroptosis, a form of iron-dependent cell death. How iron overload influences microglial function? Whether disbiosis in iron metabolism and ferroptosis in microglia are involved in neurodegenerative disorders and the underlying mechanisms remain to be elucidated. In this review we focus on the recent advances in research on microglial iron metabolism as well as ferroptosis in microglia. Meanwhile, we provide a comprehensive overview of the involvement of microglial ferroptosis in neurodegenerative disorders from the perspective of crosstalk between microglia and neuron, with a focus on Alzheimer's disease and Parkinson's disease.

Non-coding RNA: A key regulator in the Glutathione-GPX4 pathway of ferroptosis

Ferroptosis, a form of regulated cell death, has emerged as a crucial process in diverse pathophysiological states, encompassing cancer, neurodegenerative ailments, and ischemia-reperfusion injury. The glutathione (GSH)-dependent lipid peroxidation pathway, chiefly governed by glutathione peroxidase 4 (GPX4), assumes an essential part in driving ferroptosis. GPX4, as the principal orchestrator of ferroptosis, has garnered significant attention across cancer, cardiovascular, and neuroscience domains over the past decade. Noteworthy investigations have elucidated the indispensable functions of ferroptosis in numerous diseases, including tumorigenesis, wherein robust ferroptosis within cells can impede tumor advancement. Recent research has underscored the complex regulatory role of non-coding RNAs (ncRNAs) in regulating the GSH-GPX4 network, thus influencing cellular susceptibility to ferroptosis. This exhaustive review endeavors to probe into the multifaceted processes by which ncRNAs control the GSH-GPX4 network in ferroptosis. Specifically, we delve into the functions of miRNAs, lncRNAs, and circRNAs in regulating GPX4 expression and impacting cellular susceptibility to ferroptosis. Moreover, we discuss the clinical implications of dysregulated interactions between ncRNAs and GPX4 in several conditions, underscoring their capacity as viable targets for therapeutic intervention. Additionally, the review explores emerging strategies aimed at targeting ncRNAs to modulate the GSH-GPX4 pathway and manipulate ferroptosis for therapeutic advantage. A comprehensive understanding of these intricate regulatory networks furnishes insights into innovative therapeutic avenues for diseases associated with perturbed ferroptosis, thereby laying the groundwork for therapeutic interventions targeting ncRNAs in ferroptosis-related pathological conditions.

Ironing out the Links: Ferroptosis in epilepsy and SUDEP

Iron is a crucial element for almost all organisms because it plays a vital role in oxygen transport, enzymatic processes, and energy generation due to its electron transfer capabilities. However, its dysregulation can lead to a form of programmed cell death known as ferroptosis, which is characterized by cellular iron accumulation, reactive oxygen species (ROS) production, and unrestricted lipid peroxidation. Both iron and ferroptosis have been identified as key players in the pathogenesis of various neurodegenerative diseases. While in epilepsy this phenomenon remains relatively understudied, seizures can be considered hypoxic-ischemic episodes resulting in increased ROS production, lipid peroxidation, membrane disorganization, and cell death. All of this is accompanied by elevated intracellular free Fe2+ concentration and hemosiderin precipitation, as existing reports suggest a significant accumulation of iron in the brain and heart associated with epilepsy. Generalized tonic-clonic seizures (GTCS), a primary risk factor for Sudden Unexpected Death in Epilepsy (SUDEP), not only have an impact on the brain but also lead to cardiogenic dysfunctions associated with "Iron Overload and Cardiomyopathy" (IOC) and "Epileptic heart" characterized by electrical and mechanical dysfunction and a high risk of malignant bradycardia. In line with this phenomenon, studies conducted by our research group have demonstrated that recurrent seizures induce hypoxia in cardiomyocytes, resulting in P-glycoprotein (P-gp) overexpression, prolonged Q-T interval, severe bradycardia, and hemosiderin precipitation, correlating with an elevated spontaneous death ratio. In this article, we explore the intricate connections among ferroptosis, epilepsy, and SUDEP. By synthesizing current knowledge and drawing insights from recent publications, this study provides a comprehensive understanding of the molecular underpinnings. Furthermore, this review offers insights into potential therapeutic avenues and outlines future research directions.

Neuroinflammation and Neurodegenerative Diseases: How Much Do We Still Not Know?

The term "neuroinflammation" defines the typical inflammatory response of the brain closely related to the onset of many neurodegenerative diseases (NDs). Neuroinflammation is well known, but its mechanisms and pathways are not entirely comprehended. Some progresses have been achieved through many efforts and research. Consequently, new cellular and molecular mechanisms, diverse and conventional, are emerging. In listing some of those that will be the subject of our description and discussion, essential are the important roles of peripheral and infiltrated monocytes and clonotypic cells, alterations in the gut-brain axis, dysregulation of the apelinergic system, alterations in the endothelial glycocalyx of the endothelial component of neuronal vascular units, variations in expression of some genes and levels of the encoding molecules by the action of microRNAs (miRNAs), or other epigenetic factors and distinctive transcriptional factors, as well as the role of autophagy, ferroptosis, sex differences, and modifications in the circadian cycle. Such mechanisms can add significantly to understanding the complex etiological puzzle of neuroinflammation and ND. In addition, they could represent biomarkers and targets of ND, which is increasing in the elderly.