Buddlejasaponin IVb ameliorates ferroptosis of dopaminergic neuron by suppressing IRP2-mediated iron overload in Parkinson's disease

The Role and Mechanisms of Ubiquitin-Proteasome System-Mediated Ferroptosis in Neurological Disorders

Ferroptosis is a form of cell death elicited by an imbalance in intracellular iron concentrations, leading to enhanced lipid peroxidation. In neurological disorders, both oxidative stress and mitochondrial damage can contribute to ferroptosis, resulting in nerve cell dysfunction and death. The ubiquitin-proteasome system (UPS) refers to a cellular pathway in which specific proteins are tagged with ubiquitin for recognition and degradation by the proteasome. In neurological conditions, the UPS plays a significant role in regulating ferroptosis. In this review, we outline how the UPS regulates iron metabolism, ferroptosis, and their interplay in neurological diseases. In addition, we discuss the future application of small-molecule inhibitors and identify potential drug targets. Further investigation into the mechanisms of UPS-mediated ferroptosis will provide novel insights and strategies for therapeutic interventions and clinical applications in neurological diseases.

Acteoside alleviates salsolinol-induced Parkinson's disease by inhibiting ferroptosis via activating Nrf2/SLC7A11/GPX4 pathway

Salsolinol (SAL), i.e.1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroiso-quinoline, is a dopamine metabolite and endogenous neurotoxin that is toxic to dopaminergic neurons, and is involved in the genesis of Parkinson's disease (PD). However, the machinery underlying SAL induces neurotoxicity in PD are still being elucidated. In the present study, we first used RNA sequencing (RNAseq) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis to detect differentially expressed genes in SAL-treated SH-SY5Y cells. We found that ferroptosis-related pathway was enriched by SAL, which was validated by in vitro and in vivo SAL models. SAL inducing ferroptosis through downregulating SLC7A11/GPX4 in SH-SY5Y cells, which neurotoxic effect was reversed by ferroptosis inhibitors deferoxamine (DFO) and ferrostatin-1 (Fer-1). Acteoside, a phenylethanoid glycoside of plant origin with neuroprotective effect, attenuates SAL-induced neurotoxicity by inhibiting ferroptosis in in vitro and in vivo PD models through upregulating SLC7A11/GPX4. Mechanistically, acteoside activates Nrf2. Nrf2 inhibitor ML385 abolished acteoside-mediated increased SLC7A11/GPX4 and neuroprotection against SAL in SH-SY5Y cells. Meanwhile, the PI3K inhibitor LY294002 suppressed the acteoside-induced Nrf2 expression and ensued decreased expression of SLC7A11/GPX4 in SAL-treated SH-SY5Y cells. Taken together, these results demonstrate that salsolinol-induced PD through inducing ferroptosis via downregulating SLC7A11/GPX4. Acteoside attenuates SAL-induced PD through inhibiting ferroptosis via activating PI3K/Akt-dependant Nrf2. The present study revealed a novel molecular mechanisms underlining SAL-induced neurotoxicity via induction of ferroptosis in PD, and uncovered a new pharmacological effect against PD through inhibiting ferroptosis. This study highlights SAL-induced ferroptosis -dependent neurotoxicity as a potential therapeutic target in PD.

The deubiquitinase OTUD3 stabilizes IRP2 expression to reduce hippocampal neuron ferroptosis via the p53/PTGS2 pathway to ameliorate cerebral ischemia-reperfusion injury

BACKGROUND

Ischemic stroke (IS) is known for its high morbidity, disability and mortality rates, and studies designed to explore its pathophysiological mechanisms and identify novel therapeutic strategies are urgently needed. We aimed to probe the effects of the deubiquitinase OTUD3-IRP2-p53/PTGS2 pathway on cerebral ischemia‒reperfusion (I/R) injury and hippocampal neuron ferroptosis.

METHODS

A cerebral I/R mouse model was established. Furthermore, lentiviral vectors that overexpressed OTUD3 and knocked down IRP2 were constructed, and a series of assays were performed to probe the OTUD3/IRP2/p53/PTGS2 mechanism. An oxygen‒glucose deprivation and reoxygenation (OGD/R) model of mouse hippocampal neurons was constructed. Then, OTUD3 and IRP2 were knocked down and overexpressed, and p53 was overexpressed to explore the mechanism of the OTUD3/IRP2/p53/PTGS2 pathway.

RESULTS

OTUD3 and IRP2 were expressed at low levels in cerebral I/R models. OTUD3 promoted IRP2 expression to protect damaged hippocampal neurons. Moreover, IRP2 affected ferroptosis in hippocampal neurons. In addition, IRP2 inhibited p53. After IRP2 and p53 were overexpressed, IRP2 regulated the p53/PTGS2 pathway and affected ferroptosis in hippocampal neurons. In vivo, after overexpressing OTUD3 and knocking down IRP2, we found that overexpression of OTUD3 promoted IRP2 expression to reduce ferroptosis in hippocampal neurons and improve cerebral I/R injury via the inhibition of the p53/PTGS2 pathway.

CONCLUSIONS

The deubiquitinase OTUD3 stabilized IRP2 expression to reduce hippocampal neuron ferroptosis via the p53/PTGS2 pathway to subsequently ameliorate cerebral I/R injury.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Rapid Discovery of Aβ42 Fibril Disintegrators from Ganoderma lucidum via Ligand Fishing and Their Neuroprotective Effects on Alzheimer's Disease

An amyloid-β (Aβ) fibril is a vital pathogenic factor of Alzheimer's disease (AD). Aβ fibril disintegrators possess great potential to be developed into novel anti-AD agents. Here, a ligand fishing method was employed to rapidly discover Aβ42 fibril disintegrators from Ganoderma lucidum using Aβ42 fibril-immobilized magnetic beads, which led to the isolation of six Aβ42 fibril disintegrators including ganodermanontriol, ganoderic acid DM, ganoderiol F, ganoderol B, ganodermenonol, and ergosterol. Neuroprotective evaluation in vitro exhibited that these Aβ42 fibril disintegrators could significantly mitigate Aβ42-induced neurotoxicity. Among these six disintegrators, ergosterol and ganoderic acid DM with stronger protecting activity were further selected to evaluate their neuroprotective effect on AD in vivo. Results showed that ergosterol and ganoderic acid DM could significantly alleviate Aβ42-induced cognitive dysfunction and hippocampus neuron loss in vivo. Moreover, ergosterol and ganoderic acid DM could significantly inhibit Aβ42-induced neuron apoptosis and Nrf2-mediated neuron oxidative stress in vitro and in vivo.

The Role of Calcium and Iron Homeostasis in Parkinson's Disease

Calcium and iron are essential elements that regulate many important processes of eukaryotic cells. Failure to maintain homeostasis of calcium and iron causes cell dysfunction or even death. PD (Parkinson's disease) is the second most common neurological disorder in humans, for which there are currently no viable treatment options or effective strategies to cure and delay progression. Pathological hallmarks of PD, such as dopaminergic neuronal death and intracellular α-synuclein deposition, are closely involved in perturbations of iron and calcium homeostasis and accumulation. Here, we summarize the mechanisms by which Ca2+ signaling influences or promotes PD progression and the main mechanisms involved in ferroptosis in Parkinson's disease. Understanding the mechanisms by which calcium and iron imbalances contribute to the progression of this disease is critical to developing effective treatments to combat this devastating neurological disorder.