N-acetylneuraminic acid links immune exhaustion and accelerated memory deficit in diet-induced obese Alzheimer's disease mouse model

Sialic Acid-based Glycoconjugation on Myricetin-encapsulated Cationic Nanocarriers for the Treatment of Alzheimer's

PURPOSE

The current study was conducted to develop and evaluate sialic acid grafted cationic myricetin (MY) fabricated nanostructured lipid carrier (Sia-Cat-MY-NLC) for Alzheimer's disease (AD) management.

METHODS

In-vitro amyloid beta aggregation inhibition and mitochondrial membrane potential of prepared NLCs were observed in SH-SY5Y cells. The transendothelial electrical resistance was measured through hCMEC/D3 cells. Pharmacokinetic and pharmacodynamic studies were conducted to evaluate neuropharmacokinetic parameters and levels of AD hallmarks in AD rats.

RESULTS

The optimized formulations showed particle sizes (142.26 ± 24.16 nm and 236.3 ± 15.26 nm), zeta potentials (36.5 ± 2.43 mv and -2.4 ± 1.30 mv) respectively for Cat-MY-NLC and Sia-Cat-MY-NLC. Prepared NLCs treatments revealed significant neuroprotective effects in SH-SY5Y cells followed by the ability to cross the in-vitro BBB model. Results of pharmacokinetic studies showed 5.3 and 5.88 folds enhanced bioavailability with Cat-MY-NLC and Sia-Cat-MY-NLC administration respectively.

CONCLUSIONS

The results of enzymatic analysis showed a significant (p < 0.05) restoration of AD hallmark levels in the brain after Sia-Cat-MY-NLC treatment than Cat-MY-NLC.

Improved ESI-MS Sensitivity via an Imidazolium Tag (DAPMI-ITag) for Precise Sialic Acid Detection in Human Serum and CMAH-Null Mouse Tissues

Sialic acids (Sias), consisting primarily of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), play crucial roles in many biological processes. The detection and quantification of Sias are essential for understanding their roles in health and disease progression. Although numerous techniques have been developed to enhance the specificity and sensitivity of Sias analysis, traditional methods such as derivatization with fluorescent tags coupled with HPLC-MS analysis often suffer from low limits of detection, limiting the quantification of Sias in trace samples. Here, we introduce DAPMI, a novel imidazolium-based ITag for sensitive Sia detection. We demonstrate its utility in the detection and quantification of Sia composition in human serum, and in different tissues from CMAH (cytidine monophosphate-N-acetylneuraminic acid hydroxylase) knockout mice, using ESI-MS analysis and with a limit of detection (LOD) down to the low fmol range. The results showed that both Neu5Ac and Neu5Gc were present in varying proportions in wild-type mice and CMAH heterogeneous mice. Trace amounts of Neu5Gc were also detected in the tissues of CMAH null homogeneous mice (CMAH-/-) and in human blood serum using ESI-ToF-MS, suggesting its presence may be linked to dietary intake of Neu5Gc-containing foods, as Neu5Gc cannot be synthesized endogenously in CMAH-/- mice, and in humans. The DAPMI-ITag and the labeling technology developed in this study significantly improve the sensitivity of Sias detection compared to conventional tags such as o-phenylenediamine (OPD), and provide a new chemical tool for the exploration of Sias' biological roles and their use as biomarkers in different human conditions.

ATP-release pannexin channels are gated by lysophospholipids

In addition to its role as cellular energy currency, adenosine triphosphate (ATP) serves as an extracellular messenger that mediates diverse cell-to-cell communication. Compelling evidence supports that ATP is released from cells through pannexins, a family of membrane proteins that form heptameric large-pore channels. However, the activation mechanisms that trigger ATP release by pannexins remain poorly understood. Here, we discover lysophospholipids as endogenous pannexin activators, using activity-guided fractionation of mouse tissue extracts combined with untargeted metabolomics and electrophysiology. We show that lysophospholipids directly and reversibly activate pannexins in the absence of other proteins. Secretomics experiments reveal that lysophospholipid-activated pannexin 1 leads to the release of not only ATP but also other signaling metabolites, such as 5'-methylthioadenosine, which is important for immunomodulation. We also demonstrate that lysophospholipids activate endogenous pannexin 1 in human monocytes, leading to the release of IL-1β through inflammasome activation. Our results provide a connection between lipid metabolism and purinergic signaling, both of which play major roles in immune responses.

Lactobacillus Johnsonii YH1136 alleviates schizophrenia-like behavior in mice: a gut-microbiota-brain axis hypothesis study

Based on the microbiota-gut-brain axis (MGBA) hypothesis, probiotics play an increasingly important role in treating various psychiatric disorders. Schizophrenia (SCZ) is a common mental disease with a complex pathogenesis and is challenging to treat. Although studies have elucidated the mechanisms associated with the interactions between the microbiota-gut-brain axis and SCZ, few have specifically used probiotics as a therapeutic intervention for SCZ. Accordingly, the current study determines whether L. johnsonii YH1136 effectively prevents SCZ-like behavior in mice and identifies the associated key microbes and metabolites. An SCZ mouse model was established by intraperitoneal injection of MK-801; L. johnsonii YH1136 was administered via oral gavage. L. johnsonii YH1136 significantly improves abnormal behaviors, including psychomotor hyperactivity and sociability and alleviates aberrant enzyme expression associated with tryptophan metabolism in SCZ mice. Additionally, L. johnsonii YH1136 upregulates hippocampal brain-derived neurotrophic factor (BDNF) levels while downregulating tryptophan 2,3-dioxygenase (TDO2), indoleamine-pyrrole 2,3-dioxygenase 1 (IDO1), kynurenine aminotransferase 1 (KAT1). Subsequent 16S rRNA sequencing of intestinal contents suggests that L. johnsonii YH1136 modulates the gut flora structure and composition by increasing the relative abundance of Lactobacillus and decreasing Dubosiella in SCZ mice. N-acetylneuraminic acid and hypoxanthine are the key serum metabolites mediating the interaction between the MGBA and SCZ. These results partially reveal the mechanism underlying the effects of L. johnsonii YH1136 on SCZ-like behavior in mice, supporting the development of therapeutic L. johnsonii probiotic formulations against SCZ.

Immunogenic shift of arginine metabolism triggers systemic metabolic and immunological reprogramming to suppress HER2 + breast cancer

BACKGROUND

Arginine metabolism in tumors is often shunted into the pathway producing pro-tumor and immune suppressive polyamines (PAs), while downmodulating the alternative nitric oxide (NO) synthesis pathway. Aiming to correct arginine metabolism in tumors, arginine deprivation therapy and inhibitors of PA synthesis have been developed. Despite some therapeutic advantages, these approaches have often yielded severe side effects, making it necessary to explore an alternative strategy. We previously reported that supplementing sepiapterin (SEP), the endogenous precursor of tetrahydrobiopterin (BH4, the essential NO synthase cofactor), could correct arginine metabolism in tumor cells and tumor-associated macrophages (TAMs) and induce their metabolic and phenotypic reprogramming. We saw that oral SEP treatment effectively suppressed the growth of HER2-positive mammary tumors in animals. SEP also has no reported dose-dependent toxicity in clinical trials for metabolic disorders. In the present study, we tested our hypothesis that a long-term administration of SEP to individuals susceptible to HER2-positive mammary tumor would protect them against tumor occurrence.

METHODS

We administered SEP, in comparison to control DMSO, to MMTV-neu mice susceptible to HER2-positive mammary tumors for 8 months starting at their pre-pubertal stage. We monitored tumor onsets to determine the rate of tumor-free survival. After 8 months of treatment, we grouped animals into DMSO treatment with or without tumors and SEP treatment with or without tumors. We analyzed blood metabolites, PBMC, and bone marrow of DMSO vs. SEP treated animals.

RESULTS

We found that a long-term use of SEP in animals susceptible to HER2-positive mammary tumors effectively suppressed tumor occurrence. These SEP-treated animals had undergone reprogramming of the systemic metabolism and immunity, elevating total T cell counts in the circulation and bone marrow. Given that bone marrow-resident T cells are mostly memory T cells, it is plausible that chronic SEP treatment promoted memory T cell formation, leading to a potent tumor prevention.

CONCLUSIONS

These findings suggest the possible roles of the SEP/BH4/NO axis in promoting memory T cell formation and its potential therapeutic utility for preventing HER2-positive breast cancer.

Integrated analysis of immunometabolic interactions in Down syndrome

Down syndrome (DS), caused by trisomy 21 (T21), results in immune and metabolic dysregulation. People with DS experience co-occurring conditions at higher rates than the euploid population. However, the interplay between immune and metabolic alterations and the clinical manifestations of DS are poorly understood. Here, we report an integrated analysis of immunometabolic pathways in DS. Using multi-omics data, we infered cytokine-metabolite relationships mediated by specific transcriptional programs. We observed increased mediation of immunometabolic interactions in those with DS compared to euploid controls by genes in interferon response, heme metabolism, and oxidative phosphorylation. Unsupervised clustering of immunometabolic relationships in people with DS revealed subgroups with different frequencies of co-occurring conditions. Across the subgroups, we observed distinct mediation by DNA repair, Hedgehog signaling, and angiogenesis. The molecular stratification associates with the clinical heterogeneity observed in DS, suggesting that integrating multiple omic profiles reveals axes of coordinated dysregulation specific to DS co-occurring conditions.

N-Acetylneuraminic acid triggers endothelial pyroptosis and promotes atherosclerosis progression via GLS2-mediated glutaminolysis pathway

Vascular endothelial injury initiates atherosclerosis (AS) progression. N-Acetylneuraminic acid (Neu5Ac) metabolic disorder was found to intensify endothelial mitochondrial damage. And GLS2-associated glutaminolysis disorder contributed to mitochondrial dysfunction. However, mechanisms underlying Neu5Ac-associated mitochondrial dysfunction as well as its association with GLS2 remains unclear. In this study, we constructed GLS2-/-ApoE-/- mice by using HBLV-GLS2 shRNA injection. And methods like immunofluorescence, western blotting, transmission electron microscopy were applied to detect profiles of endothelial injury and AS progression both in vivo and in vitro. We demonstrated that Neu5Ac accumulation increased GLS2 expression and promoted glutaminolysis disorder, which further induced endothelial mitochondrial dysfunction via a pyroptosis-dependent pathway in vivo and in vitro. Mechanically, Neu5Ac interacted with SIRT3 and led to FOXO3a deacetylation and phosphorylation, further facilitated c-Myc antagonism and ultimately increased GLS2 levels. Inhibition of GLS2 could improve mitochondrial function and mitigate pyroptosis process. In addition, blocking Neu5Ac production using neuraminidases (NEUs) inhibitor could rescue endothelial damage and alleviate AS development in ApoE-/- mice. These findings proposed that Neu5Ac induced GLS2-mediated glutaminolysis disorder and then promoted mitochondrial dysfunction in a pyroptosis-dependent pathway. Targeting GLS2 or inhibiting Neu5Ac production could prevent AS progression.

Immunogenic shift of arginine metabolism triggers systemic metabolic and immunological reprogramming to prevent HER2+ breast cancer

Arginine metabolism in tumors is often shunted into the pathway producing pro-tumor and immune suppressive polyamines (PAs), while downmodulating the alternative nitric oxide (NO) synthesis pathway. Aiming to correct arginine metabolism in tumors, arginine deprivation therapy and inhibitors of PA synthesis have been developed. Despite some therapeutic advantages, these approaches have often yielded severe side effects, making it necessary to explore an alternative strategy. We previously reported that supplementing SEP, the endogenous precursor of BH4 (the essential NO synthase cofactor), could correct arginine metabolism in tumor cells and tumor-associated macrophages (TAMs) and induce their metabolic and phenotypic reprogramming. We saw that oral SEP treatment effectively suppressed the growth of HER2-positive mammary tumors in animals. SEP also has no reported dose-dependent toxicity in clinical trials for metabolic disorders. In the present study, we report that a long-term use of SEP in animals susceptible to HER2-positive mammary tumors effectively prevented tumor occurrence. These SEP-treated animals had undergone reprogramming of the systemic metabolism and immunity, elevating total T cell counts in the circulation and bone marrow. Given that bone marrow-resident T cells are mostly memory T cells, it is plausible that chronic SEP treatment promoted memory T cell formation, leading to a potent tumor prevention. These findings suggest the possible roles of the SEP/BH4/NO axis in promoting memory T cell formation and its potential therapeutic utility for preventing HER2-positive breast cancer.

Boosting peripheral immunity to fight neurodegeneration in the brain

Reciprocal communication between the brain and the immune system is essential for maintaining lifelong brain function. This interaction is mediated, at least in part, by immune cells recruited from both the circulation and niches at the borders of the brain. Here, we describe how immune exhaustion and senescence, even if not primary causative factors, can accelerate neurodegenerative diseases. We emphasize the role of a compromised peripheral immune system in driving neurodegeneration and discuss strategies for harnessing peripheral immunity to effectively treat neurodegenerative diseases, including the underlying mechanisms and opportunities for clinical translation. Specifically, we highlight the potential of boosting the immune system by blocking inhibitory checkpoint molecules to harness reparative immune cells in helping the brain to fight against neurodegeneration.

Machine learning on longitudinal multi-modal data enables the understanding and prognosis of Alzheimer's disease progression

Alzheimer's disease (AD) is a complex pathophysiological disease. Allowing for heterogeneity, not only in disease manifestations but also in different progression patterns, is critical for developing effective disease models that can be used in clinical and research settings. We introduce a machine learning model for identifying underlying patterns in Alzheimer's disease (AD) trajectory using longitudinal multi-modal data from the ADNI cohort and the AIBL cohort. Ten biologically and clinically meaningful disease-related states were identified from data, which constitute three non-overlapping stages (i.e., neocortical atrophy [NCA], medial temporal atrophy [MTA], and whole brain atrophy [WBA]) and two distinct disease progression patterns (i.e., NCA → WBA and MTA → WBA). The index of disease-related states provided a remarkable performance in predicting the time to conversion to AD dementia (C-Index: 0.923 ± 0.007). Our model shows potential for promoting the understanding of heterogeneous disease progression and early predicting the conversion time to AD dementia.

Molecular mechanisms linking type 2 diabetes mellitus and late-onset Alzheimer's disease: A systematic review and qualitative meta-analysis

Research evidence indicating common metabolic mechanisms through which type 2 diabetes mellitus (T2DM) increases risk of late-onset Alzheimer's dementia (LOAD) has accumulated over recent decades. The aim of this systematic review is to provide a comprehensive review of common mechanisms, which have hitherto been discussed in separate perspectives, and to assemble and evaluate candidate loci and epigenetic modifications contributing to polygenic risk linkages between T2DM and LOAD. For the systematic review on pathophysiological mechanisms, both human and animal studies up to December 2023 are included. For the qualitative meta-analysis of genomic bases, human association studies were examined; for epigenetic mechanisms, data from human studies and animal models were accepted. Papers describing pathophysiological studies were identified in databases, and further literature gathered from cited work. For genomic and epigenomic studies, literature mining was conducted by formalised search codes using Boolean operators in search engines, and augmented by GeneRif citations in Entrez Gene, and other sources (WikiGenes, etc.). For the systematic review of pathophysiological mechanisms, 923 publications were evaluated, and 138 gene loci extracted for testing candidate risk linkages. 3 57 publications were evaluated for genomic association and descriptions of epigenomic modifications. Overall accumulated results highlight insulin signalling, inflammation and inflammasome pathways, proteolysis, gluconeogenesis and glycolysis, glycosylation, lipoprotein metabolism and oxidation, cell cycle regulation or survival, autophagic-lysosomal pathways, and energy. Documented findings suggest interplay between brain insulin resistance, neuroinflammation, insult compensatory mechanisms, and peripheral metabolic dysregulation in T2DM and LOAD linkage. The results allow for more streamlined longitudinal studies of T2DM-LOAD risk linkages.

Genetically determined dietary habits and risk of Alzheimer's disease: a Mendelian randomization study

Background

Emerging evidence have suggested that dietary habits have potential implication on the development of Alzheimer's disease (AD). However, elucidating the causal relationship between specific dietary factors and AD risk remains a challenge. Therefore, our study endeavors to investigate the causal association between dietary habits and the risk of AD.

Materials and methods

We analyzed data on 231 dietary habits sourced from the UK Biobank and MRC-IEU, and AD data obtained from the FinnGen database. Employing a framework based on the classic two-sample Mendelian randomization (MR) study, we utilized the inverse-variance weighted (IVW) method as the primary analysis. Additionally, we conducted Steiger filtering and other methods to mitigate horizontal pleiotropy. The robustness of our overall findings was confirmed through multiple sensitivity analysis methods, and forward MR and reverse MR to address potential reverse causality bias.

Results

Our study evaluated the causal effect between 231 dietary habits involving over 500,000 participants of European ancestry, and 10,520 AD cases. Only oily fish intake demonstrated a significant protective causal relationship with AD following FDR correction (raw p-value = 1.28e-4, FDR p-value = 0.011, OR = 0.60, 95%CI: 0.47-0.78). Additionally, six dietary habits potentially influenced AD risk, with protective causal effects observed for average monthly intake of other alcoholic drinks (raw p-value = 0.024, FDR p-value = 0.574, OR = 0.57, 95%CI: 0.35-0.93) and tea intake (raw p-value = 0.047, FDR p-value = 0.581, OR = 0.78, 95%CI: 0.603-1.00). Conversely, detrimental causal effects were observed for the average weekly champagne plus white wine intake (raw p-value = 0.006, FDR p-value = 0.243, OR = 2.96, 95%CI: 1.37-6.38), Danish pastry intake (raw p-value = 0.036, FDR p-value = 0.574, OR = 13.33, 95%CI: 1.19-149.69), and doughnut intake (raw p-value = 0.039, FDR p-value = 0.574, OR = 7.41, 95%CI: 1.11-49.57). Moreover, the protective effect of goat's cheese intake phenotype exhibited statistical significance only in the IVW method (raw p-value<0.05).

Conclusion

Our results provide genetic support for a protective causal effect of oily fish intake on AD risk. Additionally, average monthly intake of other alcoholic drinks and tea consumption were also related with a lower risk of AD. Conversely, average weekly champagne plus white wine intake, Danish pastry intake, and doughnut intake were causally associated with increased risk of AD.

Molecular mechanism of renal lipid accumulation in diabetic kidney disease

Diabetic kidney disease (DKD) is a leading cause of end stage renal disease with unmet clinical demands for treatment. Lipids are essential for cell survival; however, renal cells have limited capability to metabolize overloaded lipids. Dyslipidaemia is common in DKD patients and renal ectopic lipid accumulation is associated with disease progression. Unveiling the molecular mechanism involved in renal lipid regulation is crucial for exploring potential therapeutic targets. In this review, we focused on the mechanism underlying cholesterol, oxysterol and fatty acid metabolism disorder in the context of DKD. Specific regulators of lipid accumulation in different kidney compartment and TREM2 macrophages, a lipid-related macrophages in DKD, were discussed. The role of sodium-glucose transporter 2 inhibitors in improving renal lipid accumulation was summarized.

Effects of dietary intervention on human diseases: molecular mechanisms and therapeutic potential

Diet, serving as a vital source of nutrients, exerts a profound influence on human health and disease progression. Recently, dietary interventions have emerged as promising adjunctive treatment strategies not only for cancer but also for neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, and metabolic disorders. These interventions have demonstrated substantial potential in modulating metabolism, disease trajectory, and therapeutic responses. Metabolic reprogramming is a hallmark of malignant progression, and a deeper understanding of this phenomenon in tumors and its effects on immune regulation is a significant challenge that impedes cancer eradication. Dietary intake, as a key environmental factor, can influence tumor metabolism. Emerging evidence indicates that dietary interventions might affect the nutrient availability in tumors, thereby increasing the efficacy of cancer treatments. However, the intricate interplay between dietary interventions and the pathogenesis of cancer and other diseases is complex. Despite encouraging results, the mechanisms underlying diet-based therapeutic strategies remain largely unexplored, often resulting in underutilization in disease management. In this review, we aim to illuminate the potential effects of various dietary interventions, including calorie restriction, fasting-mimicking diet, ketogenic diet, protein restriction diet, high-salt diet, high-fat diet, and high-fiber diet, on cancer and the aforementioned diseases. We explore the multifaceted impacts of these dietary interventions, encompassing their immunomodulatory effects, other biological impacts, and underlying molecular mechanisms. This review offers valuable insights into the potential application of these dietary interventions as adjunctive therapies in disease management.

Common genetic variation impacts stress response in the brain

To explain why individuals exposed to identical stressors experience divergent clinical outcomes, we determine how molecular encoding of stress modifies genetic risk for brain disorders. Analysis of post-mortem brain (n=304) revealed 8557 stress-interactive expression quantitative trait loci (eQTLs) that dysregulate expression of 915 eGenes in response to stress, and lie in stress-related transcription factor binding sites. Response to stress is robust across experimental paradigms: up to 50% of stress-interactive eGenes validate in glucocorticoid treated hiPSC-derived neurons (n=39 donors). Stress-interactive eGenes show brain region- and cell type-specificity, and, in post-mortem brain, implicate glial and endothelial mechanisms. Stress dysregulates long-term expression of disorder risk genes in a genotype-dependent manner; stress-interactive transcriptomic imputation uncovered 139 novel genes conferring brain disorder risk only in the context of traumatic stress. Molecular stress-encoding explains individualized responses to traumatic stress; incorporating trauma into genomic studies of brain disorders is likely to improve diagnosis, prognosis, and drug discovery.

Cholesterol 24-hydroxylase at the choroid plexus contributes to brain immune homeostasis

The choroid plexus (CP) plays a key role in remotely controlling brain function in health, aging, and disease. Here, we report that CP epithelial cells express the brain-specific cholesterol 24-hydroxylase (CYP46A1) and that its levels are decreased under different mouse and human brain conditions, including amyloidosis, aging, and SARS-CoV-2 infection. Using primary mouse CP cell cultures, we demonstrate that the enzymatic product of CYP46A1, 24(S)-hydroxycholesterol, downregulates inflammatory transcriptomic signatures within the CP, found here to be elevated across multiple neurological conditions. In vitro, the pro-inflammatory cytokine tumor necrosis factor α (TNF-α) downregulates CYP46A1 expression, while overexpression of CYP46A1 or its pharmacological activation in mouse CP organ cultures increases resilience to TNF-α. In vivo, overexpression of CYP46A1 in the CP in transgenic mice with amyloidosis is associated with better cognitive performance and decreased brain inflammation. Our findings suggest that CYP46A1 expression in the CP impacts the role of this niche as a guardian of brain immune homeostasis.

Assessing the Biological Mechanisms Linking Smoking Behavior and Cognitive Function: A Mediation Analysis of Untargeted Metabolomics

(1) Smoking is the most significant preventable health hazard in the modern world. It increases the risk of vascular problems, which are also risk factors for dementia. In addition, toxins in cigarettes increase oxidative stress and inflammation, which have both been linked to the development of Alzheimer's disease and related dementias (ADRD). This study identified potential mechanisms of the smoking-cognitive function relationship using metabolomics data from the longitudinal Wisconsin Registry for Alzheimer's Prevention (WRAP). (2) 1266 WRAP participants were included to assess the association between smoking status and four cognitive composite scores. Next, untargeted metabolomic data were used to assess the relationships between smoking and metabolites. Metabolites significantly associated with smoking were then tested for association with cognitive composite scores. Total effect models and mediation models were used to explore the role of metabolites in smoking-cognitive function pathways. (3) Plasma N-acetylneuraminate was associated with smoking status Preclinical Alzheimer Cognitive Composite 3 (PACC3) and Immediate Learning (IMM). N-acetylneuraminate mediated 12% of the smoking-PACC3 relationship and 13% of the smoking-IMM relationship. (4) These findings provide links between previous studies that can enhance our understanding of potential biological pathways between smoking and cognitive function.

Deep brain stimulation of thalamic nucleus reuniens promotes neuronal and cognitive resilience in an Alzheimer's disease mouse model

The mechanisms that confer cognitive resilience to Alzheimer's Disease (AD) are not fully understood. Here, we describe a neural circuit mechanism underlying this resilience in a familial AD mouse model. In the prodromal disease stage, interictal epileptiform spikes (IESs) emerge during anesthesia in the CA1 and mPFC regions, leading to working memory disruptions. These IESs are driven by inputs from the thalamic nucleus reuniens (nRE). Indeed, tonic deep brain stimulation of the nRE (tDBS-nRE) effectively suppresses IESs and restores firing rate homeostasis under anesthesia, preventing further impairments in nRE-CA1 synaptic facilitation and working memory. Notably, applying tDBS-nRE during the prodromal phase in young APP/PS1 mice mitigates age-dependent memory decline. The IES rate during anesthesia in young APP/PS1 mice correlates with later working memory impairments. These findings highlight the nRE as a central hub of functional resilience and underscore the clinical promise of DBS in conferring resilience to AD pathology by restoring circuit-level homeostasis.

Metabolite Neu5Ac triggers SLC3A2 degradation promoting vascular endothelial ferroptosis and aggravates atherosclerosis progression in ApoE-/-mice

Background: Atherosclerosis (AS) is still the major cause of cardiovascular disease (CVD) as well as stroke. Endothelial metabolic disorder has been found to be activated and then promote endothelial cells (ECs) injury, which is regarded to initiate AS progression. N-acetylneuraminic acid (Neu5Ac), a metabolite produced by hexosamine-sialic acid pathway branching from glucose metabolism, was presented as a notable biomarker of CVD and is positively correlated with ECs function. However, few studies explain whether Neu5Ac regulate AS progression by affecting EC function as well as its involved mechanisms are still unknown. Methods: Here, we mimicked an animal model in ApoE-/- mice which displaying similar plasma Neu5Ac levels with AS model to investigate its effect on AS progression. Results: We found that Neu5Ac exacerbated plaques area and increased lipids in plasma in absence of HFD feeding, and ECs inflammatory injury was supposed as the triggering factor upon Neu5Ac treatment with increasing expression of IL-1β, ICAM-1, and promoting ability of monocyte adhesion to ECs. Mechanistic studies showed that Neu5Ac facilitated SLC3A2 binding to ubiquitin and then triggered P62 mediated degradation, further leading to accumulation of lipid peroxidation in ECs. Fer-1 could inhibit ECs injury and reverse AS progression induced by Neu5Ac in ApoE-/- mice. Interestingly, mitochondrial dysfunction was also partly participated in ECs injury after Neu5Ac treatment and been reversed by Fer-1. Conclusions: Together, our study unveils a new mechanism by which evaluated metabolite Neu5Ac could promote SLC3A2 associated endothelial ferroptosis to activate ECs injury and AS plaque progression, thus providing a new insight into the role of Neu5Ac-ferroptosis pathway in AS. Also, our research revealed that pharmacological inhibition of ferroptosis may provide a novel therapeutic strategy for premature AS.