Brain Iron Homeostasis and Mental Disorders

Absence of astrocytic ceruloplasmin reverses the senescence process with aging of learning and memory abilities

Ceruloplasmin (CP) is a multi-copper ferroxidase mainly synthesized by liver, secreted into the peripheral blood, playing a critical role in regulating the iron homeostasis. In the central nervous system (CNS), the CP expressed by astrocytes plays an important role in the transportation of iron from the blood across the blood-brain barrier (BBB) into the brain. Our previous study showed that conditional knockout of astrocytic CP with Cre-LoxP system (CpGfapcKO) not only improved the learning and memory abilities of elderly mice, but also impaired the learning and memory abilities of young mice. In order to further investigate the effects of CP on learning and memory with aging, we constructed mice model with tamoxifen-induced astrocyte specific knockout of CP, induced CP knockout at 12 months old, and observed the effects on mouse learning and memory at 18 months old. We were delighted to found that ablation of astrocytic CP by tamoxifen at 12 months old could similarly enhance the learning, memory and recognition abilities in 18-month-old mice. Iron deposition in the hippocampus associated with aging was mitigated, leading to a reduction in oxidative stress. The MAPK/JNK pathway exhibited attenuation, while the PI3K/Akt/GSK3 pathway showed enhancement. This combination is expected to result in the reduction of the phosphorylation level of MYC and the elevation of the nuclear translocation of MYC, which might then contribute to reduced cellular senescence. Additionally, the ROS/MAPK/Erk and ROS/MAPK/p38 pathways-dependent cell apoptosis in hippocampus was diminished. The hallmarks of Alzheimer's Disease (AD) were all significantly reduced. Ultimately, the alleviated cellular senescence along with the reduction in AD-related markers, coincided with an improvement in learning, memory, and recognition abilities. These findings further elucidated the role of CP in brain iron metabolism, offering a novel target and strategy for the prevention and treatment of neurodegenerative diseases, such as AD associated with aging.

Combined transcriptomic and proteomic analyses reveal relevant myelin features in mice with ischemic stroke

Ischemic stroke (IS), a leading cause of global disability and mortality, is characterized by white matter damage and demyelination. Despite advances, the molecular mechanisms driving post-IS myelin pathology remain poorly understood, limiting therapeutic development. This study investigates key myelin-related genes (MRGs) and their regulatory networks to identify novel therapeutic targets. A transient middle cerebral artery occlusion (MCAO) model was established in C57BL/6 mice, with brain tissues collected at four timepoints (Sham0D, MCAO0D, MCAO7D, MCAO14D). Transcriptomic and proteomic sequencing were performed, followed by soft clustering (Mfuzz), functional enrichment (GO/KEGG), and ROC analysis to identify key MRGs. Competing endogenous RNA (ceRNA) networks were constructed, and drug prediction was conducted using the Comparative Toxicogenomics Database (CTD) and molecular docking. Expression validation was performed via qRT-PCR and Western blot. Integrated multi-omics analysis identified Wasf3 and Slc25a5 as key MRGs, enriched in mitochondrial respiration, calcium metabolism, and cytoskeletal regulation. The AUC values of the one-to-one model scores were all greater than 0.7, suggesting that Wasf3 and Slc25a5 were able to effectively discriminate between samples from different time points. A ceRNA network revealed critical interactions, including the Wasf3-mmu-miR-423-5p-H19 axis, linking apoptosis and myelin dysfunction. Drug prediction highlighted valproic acid (VPA) as a high-affinity binder for both genes (binding energies: - 4.2 and - 4.7 kcal/mol), suggesting its potential as a therapeutic candidate for IS. Experimental validation confirmed significant downregulation of Wasf3 mRNA (p < 0.01) and protein (p = 0.069) post-IS, while Slc25a5 showed no significant changes, potentially due to sample size limitations. This study establishes Wasf3 and Slc25a5 as pivotal regulators of post-IS myelin pathology and proposes VPA as a promising therapeutic candidate to enhance remyelination. The findings underscore the utility of multi-omics approaches in bridging molecular mechanisms to clinical translation, offering new strategies for IS diagnosis and treatment.

Emerging Ferroptosis Involvement in Amyotrophic Lateral Sclerosis Pathogenesis: Neuroprotective Activity of Polyphenols

Neurodegenerative diseases are a group of diseases that share common features, such as the generation of misfolded protein deposits and increased oxidative stress. Among them, amyotrophic lateral sclerosis (ALS), whose pathogenesis is still not entirely clear, is a complex neurodegenerative disease linked both to gene mutations affecting different proteins, such as superoxide dismutase 1, Tar DNA binding protein 43, Chromosome 9 open frame 72, and Fused in Sarcoma, and to altered iron homeostasis, mitochondrial dysfunction, oxidative stress, and impaired glutamate metabolism. The purpose of this review is to highlight the molecular targets common to ALS and ferroptosis. Indeed, many pathways implicated in the disease are hallmarks of ferroptosis, a recently discovered type of iron-dependent programmed cell death characterized by increased reactive oxygen species (ROS) and lipid peroxidation. Iron accumulation results in mitochondrial dysfunction and increased levels of ROS, lipid peroxidation, and ferroptosis triggers; in addition, the inhibition of the Xc- system results in reduced cystine levels and glutamate accumulation, leading to excitotoxicity and the inhibition of GPx4 synthesis. These results highlight the potential involvement of ferroptosis in ALS, providing new molecular and biochemical targets that could be exploited in the treatment of the disease using polyphenols.

Causal associations between iron levels in subcortical brain regions and psychiatric disorders: a Mendelian randomization study

Despite observational studies linking brain iron levels to psychiatric disorders, the exact causal relationship remains poorly understood. This study aims to examine the relationship between iron levels in specific subcortical brain regions and the risk of psychiatric disorders. Utilizing two-sample Mendelian randomization (MR) analysis, this study investigates the causal associations between iron level changes in 16 subcortical nuclei and eight major psychiatric disorders, including schizophrenia (SCZ), major depressive disorder (MDD), autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder, bipolar disorder, anxiety disorders, obsessive-compulsive disorder, and insomnia. The genetic instrumental variables linked to iron levels and psychiatric disorders were derived from the genome-wide association studies data of the UK Biobank Brain Imaging and Psychiatric Genomics Consortium. Bidirectional causal estimation was primarily obtained using the inverse variance weighting (IVW) method. Iron levels in the left substantia nigra showed a negative association with the risk of MDD (ORIVW = 0.94, 95% CI = 0.91-0.97, p < 0.001) and trends with risk of SCZ (ORIVW = 0.90, 95% CI = 0.82-0.98, p = 0.020). Conversely, iron levels in the left putamen were positively associated with the risk of ASD (ORIVW = 1.11, 95% CI = 1.04-1.19, p = 0.002). Additionally, several bidirectional trends were observed between subcortical iron levels and the risk for psychiatric disorders. Lower iron levels in the left substantia nigra may increase the risk of MDD, and potentially increase the risk of SCZ, indicating a potential shared pathogenic mechanism. Higher iron levels in the left putamen may lead to the development of ASD. The observed bidirectional trends between subcortical iron levels and psychiatric disorders, indicate the importance of the underlying biomechanical interactions between brain iron regulation and these disorders.

Effect of Moderate Red Meat Intake Compared With Plant-Based Meat Alternative on Psychological Well-Being: A 10-Wk Cluster Randomized Intervention in Healthy Young Adults

Background

A healthy diet has been proposed to support good mental health, but the addition of either red meat or meat alternatives is nuanced.

Objectives

We aimed to determine if psychological and physiological well-being is differentially affected by consuming recommended weekly amounts of either lean red meat or plant-based meat alternatives (PBMAs) supplemented with a plant-rich diet.

Methods

The trial was a parallel 2-arm randomized intervention of 10 wk duration. Eighty healthy omnivorous young adults were clustered as 40 cohabitating household pairs. Each pair was randomly assigned to consume 3 weekly servings of either fresh New Zealand beef and lamb or the equivalent PBMA. They maintained an otherwise ovo-lacto vegetarian diet, aided by a weekly meal kit and supported by engaged advice from research dietitians. Psychological measures were well-being (World Health Organization-Five Well-Being Index); depression, anxiety, and stress (depression anxiety stress scales-short form-21); and fatigue (multidimensional fatigue symptom inventory-short form) assessed weekly throughout the trial. Blood biomarkers included neurotransmitter-related compounds, iron status and vitamins B12 and D. Physical activity and sleep were estimated by a fitness wristband. Mixed effect modeling evaluated changes in each outcome over time relative to its baseline and compared the 2 interventions accounting for randomization unit clustering.

Results

Thirty-nine household pairs completed the trial. Participants measured as psychologically healthy at baseline. There were no significant differences between groups in the degree of change from baseline for the psychological outcomes, nor for the majority of the circulatory markers. Differences in changes to vitamin B12 status and 3 neurotransmitter-related compounds (adenosine, agmatine, and tyrosine) from baseline to week 10 were observed between groups. Results were similar in all sensitivity analyses when adjusting for physical activity, sleep, and diet quality covariates.

Conclusions

There was no effect on the psychological measures and limited change to physiological status when comparing a balanced diet containing either red meat or PBMAs in healthy young adults.

Identification and Correlation Analysis of Ferroptosis-Related Genes in Three Brain Regions of Patients with Schizophrenia

BACKGROUND

Schizophrenia (SZ) is a severe mental disorder that is marked by hallucinations and cognitive impairments. Ferroptosis is a type of cell death that is associated with iron and lipid peroxidation; it may play a role in SZ etiology. The present study aimed to explore the correlations between ferroptosis-related genes and SZ in three brain regions.

METHODS

We used the Gene Expression Omnibus dataset GSE80655 to analyze brain samples from SZ patients and controls; specifically, we evaluated the anterior cingulate cortex (Ancg), dorsolateral prefrontal cortex (DLPFC), and nucleus accumbens (nAcc). The data were preprocessed in R, and ferroptosis-related differentially expressed genes (DEGs) were identified. Pearson correlation analysis was then performed to assess correlations between these DEGs and age at death, postmortem interval, or brain pH. To identify important ferroptosis-related genes, we created a protein-protein interaction network using the Search Tool for the Retrieval of Interacting Genes/Proteins database, and visualized it using Cytoscape software. Moreover, the pROC package was used to calculate the area under the receiver operating characteristic curves for these important genes. Finally, gene set variation analysis was used for the pathway enrichment analysis of ferroptosis-related pathways, followed by the Wilcoxon rank-sum test.

RESULTS

Nine ferroptosis-related DEGs were upregulated in the Ancg region and one was downregulated in the nAcc region. In the Ancg region, the SZ group had four ferroptosis-related DEGs that were negatively correlated with postmortem interval, and the control group had five ferroptosis-related DEGs that were negatively correlated with brain pH. The protein-protein interaction network analysis of the Ancg region revealed seven significant interacting genes; tissue inhibitor of metalloproteinases 1 (TIMP1) and galectin 3 (LGALS3) were the hub genes. Gene set variation analysis revealed substantial changes in the glycolysis pathway in the Ancg region, and in the glutamate transmembrane transport pathway and unsaturated fatty acid biosynthesis process pathway in the nAcc region, in SZ patients compared with controls.

CONCLUSIONS

The correlation between ferroptosis and SZ appears to be stronger in the Ancg than in the nAcc or dorsolateral prefrontal cortex. This association may be mediated by TIMP1 and LGALS3 as well as by the glycolysis pathway, indicating that these might be possible biomarkers for SZ.

Microglial senescence in neurodegeneration: Insights, implications, and therapeutic opportunities

The existing literature on neurodegenerative diseases (NDDs) reveals a common pathological feature: the accumulation of misfolded proteins. However, the heterogeneity in disease onset mechanisms and the specific brain regions affected complicates the understanding of the diverse clinical manifestations of individual NDDs. Dementia, a hallmark symptom across various NDDs, serves as a multifaceted denominator, contributing to the clinical manifestations of these disorders. There is a compelling hypothesis that therapeutic strategies capable of mitigating misfolded protein accumulation and disrupting ongoing pathogenic processes may slow or even halt disease progression. Recent research has linked disease-associated microglia to their transition into a senescent state-characterized by irreversible cell cycle arrest-in aging populations and NDDs. Although senescent microglia are consistently observed in NDDs, few studies have utilized animal models to explore their role in disease pathology. Emerging evidence from experimental rat models suggests that disease-associated microglia exhibit characteristics of senescence, indicating that deeper exploration of microglial senescence could enhance our understanding of NDD pathogenesis and reveal novel therapeutic targets. This review underscores the importance of investigating microglial senescence and its potential contributions to the pathophysiology of NDDs, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Additionally, it highlights the potential of targeting microglial senescence through iron chelation and senolytic therapies as innovative approaches for treating age-related NDDs.

Iron Metabolism in the Recovery Phase of Critical Illness with a Focus on Sepsis

Iron is an essential nutrient for humans and microbes, such as bacteria. Iron deficiency commonly occurs in critically ill patients, but supplementary iron therapy is not considered during the acute phase of critical illness since it increases iron availability for invading microbes and oxidative stress. However, persistent iron deficiency in the recovery phase is harmful and has potential adverse outcomes such as cognitive dysfunction, fatigue, and cardiopulmonary dysfunction. Therefore, it is important to treat iron deficiency quickly and efficiently. This article reviews current knowledge about iron-related biomarkers in critical illness with a focus on patients with sepsis, and provides possible criteria to guide decision-making for iron supplementation in the recovery phase of those patients.

The Irony of Iron: The Element with Diverse Influence on Neurodegenerative Diseases

Iron accumulation in the brain is a common feature of many neurodegenerative diseases. Its involvement spans across the main proteinopathies involving tau, amyloid-beta, alpha-synuclein, and TDP-43. Accumulating evidence supports the contribution of iron in disease pathologies, but the delineation of its pathogenic role is yet challenged by the complex involvement of iron in multiple neurotoxicity mechanisms and evidence supporting a reciprocal influence between accumulation of iron and protein pathology. Here, we review the major proteinopathy-specific observations supporting four distinct hypotheses: (1) iron deposition is a consequence of protein pathology; (2) iron promotes protein pathology; (3) iron protects from or hinders protein pathology; and (4) deposition of iron and protein pathology contribute parallelly to pathogenesis. Iron is an essential element for physiological brain function, requiring a fine balance of its levels. Understanding of disease-related iron accumulation at a more intricate and systemic level is critical for advancements in iron chelation therapies.

The role and impact of abnormal vitamin levels in autism spectrum disorders

The prevalence of autism spectrum disorder (ASD), a neurodevelopmental disorder with a predominance of social behavioral disorders, has increased dramatically in various countries in recent decades. The interplay between genetic and environmental factors is believed to underlie ASD pathogenesis. Recent analyses have shown that abnormal vitamin levels in early life are associated with an increased risk of autism. As essential substances for growth and development, vitamins have been shown to have significant benefits for the nervous and immune systems. However, it is unknown whether certain vitamin types influence the emergence or manifestation of ASD symptoms. Several studies have focused on vitamin levels in children with autism, and neurotypical children have provided different insights into the types of vitamins and their intake. Here, we review the mechanisms and significance of several vitamins (A, B, C, D, E, and K) that are closely associated with the development of ASD in order to prevent, mitigate, and treat ASD. Efforts have been made to discover and develop new indicators for nutritional assessment of children with ASD to play a greater role in the early detection of ASD and therapeutic remission after diagnosis.