Biomimetic Remodeling of Microglial Riboflavin Metabolism Ameliorates Cognitive Impairment by Modulating Neuroinflammation

Microbiota fasting-related changes ameliorate cognitive decline in obesity and boost ex vivo microglial function through the gut-brain axis

BACKGROUND

Obesity-related cognitive decline is linked to gut microbiota dysbiosis, with emerging evidence suggesting that dietary interventions may ameliorate cognitive impairment via gut-brain axis modulation. The role of microglial cells in this process remains underexplored.

OBJECTIVE

To investigate how diet-induced changes in gut microbiota influence cognitive function in individuals with obesity and their microglial activity, and to determine the impact of specific dietary interventions.

DESIGN

This study included 96 participants with obesity who were randomised into three dietary intervention groups: Mediterranean diet (Med), alternate-day fasting (ADF) and ketogenic diet (Keto). Cognitive performance and microbiota composition were assessed pre-intervention and post-intervention. The effects of microbiota-related changes on microglial function were further evaluated in mice models through faecal transplantation and in vitro model with microbiota exosome treatment.

RESULTS

Both the Keto and ADF groups demonstrated significant weight loss, but cognitive performance improved most notably in the ADF group, in association with reduced inflammation. Diet-related microbiota composition was correlated with the cognitive outcomes in the human study. Mice models confirmed that the cognitive benefits of ADF were microbiota-dependent and linked to enhanced microglial phagocytic capacity and reduced inflammation, accompanied by changes in microglia morphology.

CONCLUSION

Fasting-induced modifications in gut microbiota contribute to cognitive improvement in individuals with obesity, with microglial cells playing a crucial mediatory role. Among the interventions, ADF most effectively enhanced microglial function and cognitive performance, suggesting its potential as a therapeutic strategy for obesity-related cognitive decline. Further studies are required to fully elucidate the underlying mechanisms.

TRIAL REGISTRATION NUMBER

NCT04453150.

Exploring the Mechanism of Kai-Xin-San to Improve Cognitive Deficits in AD Rats Induced by D-Gal and Aβ25-35 Based on Multi-Omics and Network Analysis

Alzheimer's disease (AD) is a common neurodegenerative disease for which there are no effective drugs. Kai-Xin-San (KXS), with definite curative effects, is widely used for the prevention and treatment of AD in China. But its mechanism is not yet fully understood. Based on our established rat model and previous pharmacodynamics study, Multi-omics (metabolomics, proteomics) and network analysis were integrated to explore the holistic mechanism of anti-AD effects of KXS. The key pathways were validated with western blot and ELISA methods. Morris water maze and Nissl staining showed that KXS could ameliorate cognitive deficits and pathological morphology of the hippocampus in AD rats. A total of nine metabolites were identified, which were related to pyrimidine metabolism, riboflavin metabolism, tyrosine metabolism, tryptophan metabolism, and glycerophospholipid metabolism. Proteomics results indicated that the improvement of cognitive deficits by KXS was closely related to the regulation of oxidative phosphorylation in mitochondria. Western blotting results showed that KXS significantly inhibited the expression of Mt-nd2 and Ndufb6 in AD rats. Integrated analysis indicated that the anti-AD targets of KXS were interrelated and KXS could exert its anti-AD effect by reducing oxidative stress, neurotoxicity, and inflammation.

Microglial-Biomimetic Memantine-Loaded Polydopamine Nanomedicines for Alleviating Depression

Depression is a common psychiatric disorder, and monoamine-based antidepressants as first-line therapy remain ineffective in some patients. The synergistic modulation of neuroinflammation and neuroplasticity could be a major strategy for treating depression. In this study, an inflammation-targeted microglial biomimetic system, PDA-Mem@M, is reported for treating depression. Microglial membrane-coated nanoparticles penetrate the blood-brain barrier and facilitate microglial targeting. Subsequently, owing to the excellent free radical-scavenging capacity, PDA-Mem@M attenuate the brain inflammatory microenvironment. After on-demand release from the nanoparticles, memantine increases the expression of brain-derived neurotrophic factors and reverses the loss of synaptic dendritic spines. Further, in vivo studies demonstrate that PDA-Mem@M effectively alleviate depression-like behaviors to a greater extent than memantine or polydopamine nanoparticles (PDA) monotherapy. This synergistic strategy, with satisfactory biosafety and strong anti-inflammatory and synaptic plasticity restoration effects, is conducive to advances in depression therapy.

Associations of prenatal metal exposure with child neurodevelopment and mediation by perturbation of metabolic pathways

Prenatal exposure to metals has been associated with impaired neurodevelopment in children, but the detailed molecular mechanisms remain largely unknown. Based on the Wuhan Healthy Baby Cohort, China (N = 1088), eleven metals were measured in maternal urine during early pregnancy (13.1 ± 1.1 weeks) and metabolomics profiling was conducted in cord blood. Neurodevelopment was evaluated using the Bayley Scales of Infant Development in 2-year-old children to obtain the mental development index (MDI) and psychomotor development index (PDI). After false discovery rate correction, higher maternal urinary levels of manganese, nickel, aluminum, rubidium, gallium, and the summary score of metals were only significantly associated with lower MDI scores. The weighted quantile sum index of the metal mixture showed a significant inverse association with MDI and PDI scores, with aluminum contributing the most to the associations. Histidine, beta-alanine, purine, and pyrimidine metabolism significantly mediated the above associations, suggesting that disturbances in amino acids, neurotransmitter and neuroendocrine metabolism may be important mediators in contributing to impaired neurodevelopment of children.

Myocardia-Injected Synergistically Anti-Apoptotic and Anti-Inflammatory Poly(amino acid) Hydrogel Relieves Ischemia-Reperfusion Injury

Reperfusion therapy is the most effective treatment for acute myocardial infarction, but its efficacy is frequently limited by ischemia-reperfusion injury (IRI). While antioxidant and anti-inflammatory therapies have shown significant potential in alleviating IRI, these strategies have not yielded satisfactory clinical outcomes. For that, a thermo-sensitive myocardial-injectable poly(amino acid) hydrogel of methoxy poly(ethylene glycol)45-poly(L-methionine20-co-L-alanine10) (mPEG45-P(Met20-co-Ala10), PMA) loaded with FTY720 (PMA/FTY720) is developed to address IRI through synergistic anti-apoptotic and anti-inflammatory effects. Upon injection into the ischemic myocardium, the PMA aqueous solution undergoes a sol-to-gel phase transition and gradually degrades in response to reactive oxygen species (ROS), releasing FTY720 on demand. PMA acts synergistically with FTY720 to inhibit cardiomyocyte apoptosis and modulate pro-inflammatory M1 macrophage polarization toward anti-inflammatory M2 macrophages by clearing ROS, thereby mitigating the inflammatory response and promoting vascular regeneration. In a rat IRI model, PMA/FTY720 reduces the apoptotic cell ratio by 81.8%, increases vascular density by 34.0%, and enhances left ventricular ejection fraction (LVEF) by 12.8%. In a rabbit IRI model, the gel-based sustained release of FTY720 enhanced LVEF by an additional 7.2% compared to individual treatment. In summary, the engineered PMA hydrogel effectively alleviates IRI through synergistic anti-apoptosis and anti-inflammation actions, offering valuable clinical potential for treating myocardial IRI.

Sevoflurane anesthesia during late gestation induces cognitive disorder in rat offspring via the TLR4/BDNF/TrkB/CREB pathway

Sevoflurane (Sevo) is widely used for general anesthesia during pregnancy. Emerging evidence indicates that maternal Sevo exposure can trigger developmental neurotoxicity in the offspring. Nonetheless, the underlying mechanisms need further investigation. Pregnant Sprague-Dawley rats on gestational day 18 were exposed to 3.5% Sevo to induce the rat model of neurotoxicity. TAK-242, a TLR4 inhibitor, was administrated to inhibit the signaling transduction. Hippocampal tissues of rat offspring were harvested for immunohistochemical staining, TUNEL staining, Western blotting, ELISA, and measurement of oxidative stress-related markers. Serum samples were collected to evaluate lipid metabolism-associated factors. Morris water maze was implemented to test the cognitive function of offspring rats. Rat hippocampal neurons were isolated to elucidate the effect of TAK-242 on the BDNF/TrkB/CREB signaling in vitro. The results showed that maternal Sevo exposure during the third trimester induced neuroinflammation, lipid metabolism disturbance, and oxidative stress, and impaired the spatial learning and memory of rat offspring. Sevo upregulated TLR4 and impeded BDNF/TrkB/CREB signaling transduction in the hippocampus of rat offspring; TAK-242 administration reversed these effects. In conclusion, Sevo anesthesia during late gestation impairs the learning and memory ability of rat offspring possibly by promoting neuroinflammation and disturbing lipid metabolism via the TLR4/BDNF/TrkB/CREB pathway.

Ganoderma lucidum polysaccharide alleviates cognitive dysfunction by inhibiting neuroinflammation via NLRP3/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum (G. lucidum), a traditional Chinese medicinal herb, is commonly recommended for its potential to promote mental relaxation and alleviate memory impairment. Recently, there have been reports suggesting that it exhibits anti-neuroinflammatory activity through the gut-brain axis. Cognitive dysfunction is among the most prevalent neurodegenerative diseases.

AIM OF THE STUDY

This study aimed to investigate the efficacy of polysaccharides extracted from G. lucidum in alleviating cognitive dysfunction.

METHODS AND MATERIALS

A polysaccharide was extracted through the process of alkali extraction followed by alcohol precipitation. Comprehensive analysis was conducted to characterize the total sugar content, amino acid composition, and sugar chain structure. The levels of inflammatory related factors were assessed using griess reagent, qPCR and western blotting assay in vitro. The efficacy of alleviating cognitive dysfunction was evaluated through a series of behavioral studies in mice model induced by the high-fat high-sugar diet combined with chronic unpredictable mild stress (HFFD/CUMS) in vivo. The mechanism was investigated by 16S rRNA sequence, immunohistochemistry, flow cytometry and short-chain fatty acid detection.

RESULTS

Ganoderma lucidum polysaccharide (GLP) is a polysaccharide identified as β-glucan. Bioactivity experiments have demonstrated that GLP possesses the potential to ameliorate cognitive dysfunction. The mechanism study revealed that GLP can modulate the composition of gut microbiota and suppress the activation of inflammasomes via NLRP3/NF-κB signaling pathway, thereby attenuating neuroinflammatory. Furthermore, GLP may enhance the peripheral immunity response of the body, leading to a comprehensive regulatory effect.

CONCLUSION

A polysaccharide alleviates cognitive dysfunction via inhibiting neuroinflammation.

Nanoscale drug formulations for the treatment of Alzheimer's disease progression

Alzheimer's disease (AD) is a devastating neurodegenerative disorder with no effective disease-modifying treatments. The blood-brain barrier hinders drug delivery to the brain, limiting therapeutic efficacy. Nanoparticle-based systems have emerged as promising tools to overcome these challenges. This review highlights recent advances in nanoparticle technologies for AD treatment, including liposomes, polymeric, inorganic, and biomimetic nanoparticles. These nanoparticles improve drug delivery across the blood-brain barrier, improve stability and bioavailability, and enable targeted delivery to affected brain regions. Functionalization strategies further enhance their therapeutic potential. Multifunctional nanoparticles combining therapeutic and diagnostic properties offer theranostic approaches. While progress has been made, challenges related to safety, targeting precision, and clinical translation remain. Future perspectives emphasize the need for collaborative efforts to optimize nanoparticle design, conduct rigorous studies, and accelerate the development of effective nanotherapeutics. With continued innovation, nanoparticle-based delivery systems hold great promise for revolutionizing AD treatment.

Flavins and Flavoproteins in the Neuroimmune Landscape of Stress Sensitization and Major Depressive Disorder

Major Depressive Disorder (MDD) is a common and severe neuropsychiatric condition resulting in irregular alterations in affect, mood, and cognition. Besides the well-studied neurotransmission-related etiologies of MDD, several biological systems and phenomena, such as the hypothalamic-pituitary-adrenal (HPA) axis, reactive oxygen species (ROS) production, and cytokine signaling, have been implicated as being altered and contributing to depressive symptoms. However, the manner in which these factors interact with each other to induce their effects on MDD development has been less clear, but is beginning to be understood. Flavins are potent biomolecules that regulate many redox activities, including ROS generation and energy production. Studies have found that circulating flavin levels are modulated during stress and MDD. Flavins are also known for their importance in immune responses. This review offers a unique perspective that considers the redox-active cofactors, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), as vital substrates for linking MDD-related maladaptive processes together, by permitting stress-induced enhancement of microglial interleukin-1 beta (IL-1β) signaling.

Highly BBB-permeable nanomedicine reverses neuroapoptosis and neuroinflammation to treat Alzheimer's disease

The prevalence of Alzheimer's disease (AD) is increasing globally due to population aging. However, effective clinical treatment strategies for AD still remain elusive. The mechanisms underlying AD onset and the interplay between its pathological factors have so far been unclear. Evidence indicates that AD progression is ultimately driven by neuronal loss, which in turn is caused by neuroapoptosis and neuroinflammation. Therefore, the inhibition of neuroapoptosis and neuroinflammation could be a useful anti-AD strategy. Nonetheless, the delivery of active drug agents into the brain parenchyma is hindered by the blood-brain barrier (BBB). To address this challenge, we fabricated a black phosphorus nanosheet (BP)-based methylene blue (MB) delivery system (BP-MB) for AD therapy. After confirming the successful preparation of BP-MB, we proved that its BBB-crossing ability was enhanced under near-infrared light irradiation. In vitro pharmacodynamics analysis revealed that BP and MB could synergistically scavenge excessive reactive oxygen species (ROS) in okadaic acid (OA)-treated PC12 cells and lipopolysaccharide (LPS)-treated BV2 cells, thus efficiently reversing neuroapoptosis and neuroinflammation. To study in vivo pharmacodynamics, we established a mouse model of AD mice, and behavioral tests confirmed that BP-MB treatment could successfully improve cognitive function in these animals. Notably, the results of pathological evaluation were consistent with those of the in vitro assays. The findings demonstrated that BP-MB could scavenge excessive ROS and inhibit Tau hyperphosphorylation, thereby alleviating downstream neuroapoptosis and regulating the polarization of microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype. Overall, this study highlights the therapeutic potential of a smart nanomedicine with the capability of reversing neuroapoptosis and neuroinflammation for AD treatment.

Advancing Alzheimer's Disease Modelling by Developing a Refined Biomimetic Brain Microenvironment for Facilitating High-Throughput Screening of Pharmacological Treatment Strategies

Alzheimer's disease (AD) poses a significant worldwide health challenge, requiring novel approaches for improved models and treatment development. This comprehensive review emphasises the systematic development and improvement of a biomimetic brain environment to address the shortcomings of existing AD models and enhance the efficiency of screening potential drug treatments. We identify drawbacks in traditional models and emphasise the necessity for more physiologically accurate systems through an in-depth analysis of current literature. This review aims to study the development of an advanced AD model that accurately replicates key AD pathophysiological aspects using cutting-edge biomaterials and microenvironment design. Incorporating biomolecular elements like Tau proteins and beta-amyloid (Aβ) plaques improve the accuracy of illustrating disease mechanisms. The expected results involve creating a solid foundation for high-throughput screening with enhanced scalability, translational significance, and the possibility of speeding up drug discovery. Thus, this review fills the gaps in AD modelling and shows potential for creating precise and efficient drug treatments for AD.

Research hotspots and trends on NF-κB in cognitive impairment: a bibliometric analysis

Background

Cognitive impairment (CI) endangers the physical and mental health of patients in a significant manner, and it is expected that the number of people with CI in China will rise to 45.33 million by 2050. Therefore, CI has become a popular research topic. Inflammatory damage plays a key role in the pathogenesis of CI, and NF-κB is an important inflammatory signaling pathway. However, no bibliometric analysis regarding the relationship between CI and NF-κB has been reported.

Methods

A bibliometric analysis regarding NF-κB and CI from 1 January 2008 to 12 December 2023 was conducted in the Science Citation Index-Expanded of the Web of Science Core Collection. The frontiers, hotspots, and trends of research regarding the role of NF-κB in CI were identified. VOSviewer and CiteSpace were used to analyze the retrieved articles and identify the author, country, institution, and keywords, as well as co-cited authors, co-cited journals, and co-cited references.

Results

We analyzed 1,468 original articles and reviews. Publications on NF-κB in CI began in 2010 and increased sharply in 2018. Hong Hao was the most represented author, having published 19 articles, and Chinese authors published more studies than those from other countries. China Pharmaceutical University published the most papers; however, the United States has a strong influence and demonstrates international cooperation. The keywords "apolipoprotein e" and "therapeutic target" demonstrated strong citation bursts, and this tendency may persist in the upcoming years. Neuroinflammation demonstrated a strong influence in research regarding NF-κB in CI. Gut microbiota and ketogenic diet also play an important role in NF-κB in CI.

Conclusion

This bibliometric analysis and visualization using VOSviewer and CiteSpace revealed that the role of NF-κB in CI has become a research hotspot. The results of this study indicated that "neuroinflammation," "microglial," and "pathway" remain hotspots for future research. However, studies regarding NF-κB in CI have predominantly focussed on basic research; future research should include therapeutic targets, microbiota, and ketogenic diet.

Nanotherapeutic Approaches of Interleukin-3 to Clear the α-Synuclein Pathology in Mouse Models of Parkinson's Disease

Astrocyte-microglia crosstalk is vital for neuronal survival and clearing aggregate accumulation in neurodegenerative diseases. While interleukin-3 (IL-3) has been reported to exert both protective and detrimental effects in neurodegenerative diseases, however, its role in α-synuclein pathology remains unclear. In this study, it is found that astrocytic IL-3 and microglial IL-3R are positively responsive to α-synuclein pathology in the brains of transgenic A53T Parkinson's disease (PD) mice and in an adeno-associated virus (AAV)-human α-synuclein (AAV-hα-Syn)-injected PD mouse model. Exogenous IL-3 infusion reduces behavioral abnormities and nigrostriatal α-synuclein pathology. Mechanistically, IL-3 induces microglial phagocytosis of pathological α-synuclein while simultaneously stimulating dopaminergic (DA) neurons to clear pathological α-synuclein via induction of autophagy through the IFN-β/Irgm1 pathway. Due to its limited efficiency in crossing the blood-brain barrier, a precise IL-3 delivery strategy is developed by cross-linking IL-3 and RVG29 with PEG-Linker (RVG-modified IL-3 nanogels-RVG-IL3 NGs). Intravenous administration of RVG-IL3 NGs shows efficient uptake by microglia and DA neurons within the brain. RVG-IL3 NGs ameliorate motor deficits and pathological α-synuclein by improving microglial and neuronal function in the AAV-hα-Syn mouse model of PD. Collectively, IL-3 may represent a feasible therapeutic strategy for PD.

Alzheimer's Disease, Obesity, and Type 2 Diabetes: Focus on Common Neuroglial Dysfunctions (Critical Review and New Data on Human Brain and Models)

BACKGROUND/OBJECTIVES

Obesity, type 2 diabetes (T2D), and Alzheimer's disease (AD) are pathologies that affect millions of people worldwide. They have no effective therapy and are difficult to prevent and control when they develop. It has been known for many years that these diseases have many pathogenic aspects in common. We highlight in this review that neuroglial cells (astroglia, oligodendroglia, and microglia) play a vital role in the origin, clinical-pathological development, and course of brain neurodegeneration. Moreover, we include the new results of a T2D-AD mouse model (APP+PS1 mice on a high-calorie diet) that we are investigating.

METHODS

Critical bibliographic revision and biochemical neuropathological study of neuroglia in a T2D-AD model.

RESULTS

T2D and AD are not only "connected" by producing complex pathologies in the same individual (obesity, T2D, and AD), but they also have many common pathogenic mechanisms. These include insulin resistance, hyperinsulinemia, hyperglycemia, oxidative stress, mitochondrial dysfunction, and inflammation (both peripheral and central-or neuroinflammation). Cognitive impairment and AD are the maximum exponents of brain neurodegeneration in these pathological processes. both due to the dysfunctions induced by metabolic changes in peripheral tissues and inadequate neurotoxic responses to changes in the brain. In this review, we first analyze the common pathogenic mechanisms of obesity, T2D, and AD (and/or cerebral vascular dementia) that induce transcendental changes and responses in neuroglia. The relationships between T2D and AD discussed mainly focus on neuroglial responses. Next, we present neuroglial changes within their neuropathological context in diverse scenarios: (a) aging involution and neurodegenerative disorders, (b) human obesity and diabetes and obesity/diabetes models, (c) human AD and in AD models, and (d) human AD-T2D and AD-T2D models. An important part of the data presented comes from our own studies on humans and experimental models over the past few years. In the T2D-AD section, we included the results of a T2D-AD mouse model (APP+PS1 mice on a high-calorie diet) that we investigated, which showed that neuroglial dysfunctions (astrocytosis and microgliosis) manifest before the appearance of amyloid neuropathology, and that the amyloid pathology is greater than that presented by mice fed a normal, non-high-caloric diet A broad review is finally included on pharmacological, cellular, genic, and non-pharmacological (especially diet and lifestyle) neuroglial-related treatments, as well as clinical trials in a comparative way between T2D and AD. These neuroglial treatments need to be included in the multimodal/integral treatments of T2D and AD to achieve greater therapeutic efficacy in many millions of patients.

CONCLUSIONS

Neuroglial alterations (especially in astroglia and microglia, cornerstones of neuroinflammation) are markedly defining brain neurodegeneration in T2D and A, although there are some not significant differences between each of the studied pathologies. Neuroglial therapies are a very important and p. promising tool that are being developed to prevent and/or treat brain dysfunction in T2D-AD. The need for further research in two very different directions is evident: (a) characterization of the phenotypic changes of astrocytes and microglial cells in each region of the brain and in each phase of development of each isolated and associated pathology (single-cell studies are mandatory) to better understand the pathologies and define new therapeutic targets; (b) studying new therapeutic avenues to normalize the function of neuroglial cells (preventing neurotoxic responses and/or reversing them) in these pathologies, as well as the phenotypic characteristics in each moment of the course and place of the neurodegenerative process.

A novel biomimetic nanovesicle containing caffeic acid-coupled carbon quantum dots for the the treatment of Alzheimer's disease via nasal administration

Alzheimer's disease (AD) is a common neurodegenerative disease characterized by progressive cognitive and physical impairment. Neuroinflammation is related to AD, and the misfolding and aggregation of amyloid protein in the brain creates an inflammatory microenvironment. Microglia are the predominant contributors to neuroinflammation, and abnormal activation of microglia induces the release of a large amount of inflammatory factors, promotes neuronal apoptosis, and leads to cognitive impairment. In this study, we used microglial membranes containing caffeic acid-coupled carbon quantum dots to prepare a novel biomimetic nanocapsule (CDs-CA-MGs) for the treatment of AD. The application of CDs-CA-MGs via nasal administration can bypass the blood‒brain barrier (BBB) and directly target the site of inflammation. After treatment with CDs-CA-MGs, AD mice showed reduced inflammation in the brain, decreased neuronal apoptosis, and significantly improved learning and memory abilities. In addition, CDs-CA-MGs affect inflammation-related JAK-STAT and Toll-like receptor signaling pathways in AD mice. CDs-CA-MGs significantly downregulated interleukins (IL-1β and IL-6) and tumor necrosis factor (TNF-α). This finding suggested that CDs-CA-MGs may improve cognitive impairment by modulating inflammatory responses. In conclusion, the use of CDs-CA-MGs provides a possible therapeutic strategy for the treatment of AD.

Riboflavin for women's health and emerging microbiome strategies

Riboflavin (vitamin B2) is an essential water-soluble vitamin that serves as a precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). FMN and FAD are coenzymes involved in key enzymatic reactions in energy metabolism, biosynthesis, detoxification and electron scavenging pathways. Riboflavin deficiency is prevalent worldwide and impacts women's health due to riboflavin demands linked to urogenital and reproductive health, hormonal fluctuations during the menstrual cycle, pregnancy, and breastfeeding. Innovative functional foods and nutraceuticals are increasingly developed to meet women's riboflavin needs to supplement dietary sources. An emerging and particularly promising strategy is the administration of riboflavin-producing lactic acid bacteria, combining the health benefits of riboflavin with those of probiotics and in situ riboflavin production. Specific taxa of lactobacilli are of particular interest for women, because of the crucial role of Lactobacillus species in the vagina and the documented health effects of other Lactobacillaceae taxa in the gut and on the skin. In this narrative review, we synthesize the underlying molecular mechanisms and clinical benefits of riboflavin intake for women's health, and evaluate the synergistic potential of riboflavin-producing lactobacilli and other microbiota.

ABBV-744 alleviates LPS-induced neuroinflammation via regulation of BATF2-IRF4-STAT1/3/5 axis

Suppression of neuroinflammation using small molecule compounds targeting the key pathways in microglial inflammation has attracted great interest. Recently, increasing attention has been gained to the role of the second bromodomain (BD2) of the bromodomain and extra-terminal (BET) proteins, while its effect and molecular mechanism on microglial inflammation has not yet been explored. In this study, we evaluated the therapeutic effects of ABBV-744, a BD2 high selective BET inhibitor, on lipopolysaccharide (LPS)-induced microglial inflammation in vitro and in vivo, and explored the key pathways by which ABBV-744 regulated microglia-mediated neuroinflammation. We found that pretreatment of ABBV-744 concentration-dependently inhibited the expression of LPS-induced inflammatory mediators/enzymes including NO, TNF-α, IL-1β, IL-6, iNOS, and COX-2 in BV-2 microglial cells. These effects were validated in LPS-treated primary microglial cells. Furthermore, we observed that administration of ABBV-744 significantly alleviated LPS-induced activation of microglia and transcriptional levels of pro-inflammatory factors TNF-α and IL-1β in mouse hippocampus and cortex. RNA-Sequencing (RNA-seq) analysis revealed that ABBV-744 induced 508 differentially expressed genes (DEGs) in LPS-stimulated BV-2 cells, and gene enrichment and gene expression network analysis verified its regulation on activated microglial genes and inflammatory pathways. We demonstrated that pretreatment of ABBV-744 significantly reduced the expression levels of basic leucine zipper ATF-like transcription factor 2 (BATF2) and interferon regulatory factor 4 (IRF4), and suppressed JAK-STAT signaling pathway in LPS-stimulated BV-2 cells and mice, suggesting that the anti-neuroinflammatory effect of ABBV-744 might be associated with regulation of BATF2-IRF4-STAT1/3/5 pathway, which was confirmed by gene knockdown experiments. This study demonstrates the effect of a BD2 high selective BET inhibitor, ABBV-744, against microglial inflammation, and reveals a BATF2-IRF4-STAT1/3/5 pathway in regulation of microglial inflammation, which might provide new clues for discovery of effective therapeutic strategy against neuroinflammation.

Association between vitamin B2 intake and cognitive performance among older adults: a cross-sectional study from NHANES

The impact of vitamin B2 (riboflavin) intake on cognitive performance among older adults in the United States (US) remains inadequately understood. This study aimed to explore the association between vitamin B2 intake and cognitive performance among non-institutionalized elderly people in the US. Weighted logistic regression was used to evaluate the association between vitamin B2 intake and cognitive performance. Vitamin B2 intake was determined from the mean of two 24-hour dietary recall interviews. Three cognitive ability assessment tests, namely the Immediate Recall Test (IRT), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST), were performed. Participants included all older adults over 60 who underwent cognitive scoring, with cut-offs defined based on the lowest quartile (25th percentile) for each test (the cut-offs for the three scores were 15.625, 12, and 33, respectively). Sensitivity analysis, including dose-response curves, subgroup analyses, interaction effects, per 1 standard deviation (SD), recommended dietary allowance (RDA), and residual energy model analysis, were performed to solidify the solid association between vitamin B2 and cognitive performance. A total of 2893 individuals aged over 60 were included, with a mean age of 69 (7) years, and 46% were men. There was a significant association between vitamin B2 intake and all three cognitive scores (IRT, Odds Ratio = 0.77, 95% confidence interval: [0.65,0.92]; AFT, 0.75, [0.64,0.88]; DSST, 0.72, [0.59,0.88]). Moreover, vitamin B2 intake above the RDA reduced the risk of low cognitive performance (IRT, 0.66, [0.46,0.93]; AFT, 0.83, [0.62,1.11]; DSST, 0.65, [0.45,0.92]) compared to intake below the RDA. Dose-response curves indicated that higher vitamin B2 intake was negatively associated with the risk of low cognitive performance. Physical activity may modify the association between vitamin B2 and cognitive performance. Vitamin B2 intake was positively associated with cognitive performance among older adults. Adequate vitamin B2 intake could help protect cognitive function.

Identification and analysis correlation between hub genes and immune cell infiltration related to LPS-induced cognitive impairment

Background

The occurrence of immunity and inflammation outside the central nervous system frequently results in acute cognitive impairment among elderly patients. However, there is currently a lack of standardized methods for diagnosing acute cognitive impairment. The objective of our study was to identify potential mRNA biomarkers and investigate the pathogenesis of acute cognitive impairment in mice brains.

Methods

To analyze changes in hub genes associated with acute cognitive impairment, bioinformatics analysis was performed on the mouse brain injury data of sterile saline control group and lipopolysaccharide (LPS) induced experimental group in Gene Expression Omnibus (GEO). Functional analysis was conducted using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), which facilitated to identify some potential mRNA biomarkers for hub gene expression in mice brains. Additionally, the "CIBERSORT X″ R kit was employed to examine immune cell infiltrations of mice brains in LPS group and saline group.

Results

In the LPS and saline group, 102 significantly upregulated differentially expressed genes (DEGs) and 32 downregulated DEGs were identified. The pathway enrichment analysis using GO and KEGG revealed that these DEGs were mainly related to the regulation of cytokine, cytokine-cytokine receptor interaction, as well as protein interaction with cytokine and cytokine receptor. Immune cell infiltration analysis indicated potential involvement of M1 macrophages, NK cells resting, T cells CD4 memory, and T cells CD8 naive in the process of cognitive impairment. By constructing a protein-protein interaction (PPI) network, five hub genes (Cxcl10, Cxcl12, Cxcr3, Gbp2, and Ifih1) showed significant associations with immune cell types by using a threshold Spearman's rank correlation coefficient of R > 0.50 and p < 0.05.

Conclusion

The mRNA expression profile of the mice brain tissues in the LPS group differed from that in the normal saline group. These significantly expressed mRNAs may act an importance in the pathogenesis of acute cognitive impairment through mechanisms involving immunity and neuroinflammation.

Reconstituting gut microbiota-colonocyte interactions reverses diet-induced cognitive deficits: The beneficial of eucommiae cortex polysaccharides

Rationale: Consumption of a high-fat diet (HFD) has been implicated in cognitive deficits and gastrointestinal dysfunction in humans, with the gut microbiota emerging as a pivotal mediator of these diet-associated pathologies. The introduction of plant-based polysaccharides into the diet as a therapeutic strategy to alleviate such conditions is gaining attention. Nevertheless, the mechanistic paradigm by which polysaccharides modulate the gut microbiota remains largely undefined. This study investigated the mechanisms of action of Eucommiae cortex polysaccharides (EPs) in mitigating gut dysbiosis and examined their contribution to rectifying diet-related cognitive decline. Methods: Initially, we employed fecal microbiota transplantation (FMT) and gut microbiota depletion to verify the causative role of changes in the gut microbiota induced by HFD in synapse engulfment-dependent cognitive impairments. Subsequently, colonization of the gut of chow-fed mice with Escherichia coli (E. coli) from HFD mice confirmed that inhibition of Proteobacteria by EPs was a necessary prerequisite for alleviating HFD-induced cognitive impairments. Finally, supplementation of HFD mice with butyrate and treatment of EPs mice with GW9662 demonstrated that EPs inhibited the expansion of Proteobacteria in the colon of HFD mice by reshaping the interactions between the gut microbiota and colonocytes. Results: Findings from FMT and antibiotic treatments demonstrated that HFD-induced cognitive impairments pertaining to neuronal spine loss were contingent on gut microbial composition. Association analysis revealed strong associations between bacterial taxa belonging to the phylum Proteobacteria and cognitive performance in mice. Further, introducing E. coli from HFD-fed mice into standard diet-fed mice underscored the integral role of Proteobacteria proliferation in triggering excessive synaptic engulfment-related cognitive deficits in HFD mice. Crucially, EPs effectively counteracted the bloom of Proteobacteria and subsequent neuroinflammatory responses mediated by microglia, essential for cognitive improvement in HFD-fed mice. Mechanistic insights revealed that EPs promoted the production of bacteria-derived butyrate, thereby ameliorating HFD-induced colonic mitochondrial dysfunction and reshaping colonocyte metabolism. This adjustment curtailed the availability of growth substrates for facultative anaerobes, which in turn limited the uncontrolled expansion of Proteobacteria. Conclusions: Our study elucidates that colonocyte metabolic disturbances, which promote Proteobacteria overgrowth, are a likely cause of HFD-induced cognitive deficits. Furthermore, dietary supplementation with EPs can rectify behavioral dysfunctions associated with HFD by modifying gut microbiota-colonocyte interactions. These insights contribute to the broader understanding of the modulatory effects of plant prebiotics on the microbiota-gut-brain axis and suggest a potential therapeutic avenue for diet-associated cognitive dysfunction.

Integrative transcriptome-proteome approach reveals key hypoxia-related features involved in the neuroprotective effects of Yang Xue oral liquid on Alzheimer's and Parkinson's disease

Introduction: This study investigates the role of hypoxia-related genes in the neuroprotective efficacy of Yang Xue oral liquid (YXKFY) in Alzheimer's disease (AD) and Parkinson's disease (PD). Methods and results: Using differential expression and weighted gene co-expression network analysis (WGCNA), we identified 106 and 9 hypoxia-associated genes in AD and PD, respectively, that are implicated in the transcriptomic and proteomic profiles. An artificial intelligence-driven hypoxia signature (AIDHS), comprising 17 and 3 genes for AD and PD, was developed and validated across nine independent cohorts (n = 1713), integrating 10 machine learning algorithms and 113 algorithmic combinations. Significant associations were observed between AIDHS markers and immune cells in AD and PD, including naive CD4+ T cells, macrophages, and neutrophils. Interactions with miRNAs (hsa-miR-1, hsa-miR-124) and transcription factors (USF1) were also identified. Single-cell RNA sequencing (scRNA-seq) data highlighted distinct expression patterns of AIDHS genes in various cell types, such as high expression of TGM2 in endothelial cells, PDGFRB in endothelial and mesenchymal cells, and SYK in microglia. YXKFY treatment was shown to repair cellular damage and decrease reactive oxygen species (ROS) levels. Notably, genes with previously dysfunctional expression, including FKBPL, TGM2, PPIL1, BLVRB, and PDGFRB, exhibited significant recovery after YXKFY treatment, associated with riboflavin and lysicamine. Conclusion: The above genes are suggested to be central to hypoxia and neuroinflammation responses in AD and PD, and are potential key mediators of YXKFY's neuroprotective action.

Hybrid Membrane-Coated Nanoparticles for Precise Targeting and Synergistic Therapy in Alzheimer's Disease

The blood brain barrier (BBB) limits the application of most therapeutic drugs for neurological diseases (NDs). Hybrid cell membrane-coated nanoparticles derived from different cell types can mimic the surface properties and functionalities of the source cells, further enhancing their targeting precision and therapeutic efficacy. Neuroinflammation has been increasingly recognized as a critical factor in the pathogenesis of various NDs, especially Alzheimer's disease (AD). In this study, a novel cell membrane coating is designed by hybridizing the membrane from platelets and chemokine (C-C motif) receptor 2 (CCR2) cells are overexpressed to cross the BBB and target neuroinflammatory lesions. Past unsuccessful endeavors in AD drug development underscore the challenge of achieving favorable outcomes when utilizing single-mechanism drugs.Two drugs with different mechanisms of actions into liposomes are successfully loaded to realize multitargeting treatment. In a transgenic mouse model for familial AD (5xFAD), the administration of these drug-loaded hybrid cell membrane liposomes results in a significant reduction in amyloid plaque deposition, neuroinflammation, and cognitive impairments. Collectively, the hybrid cell membrane-coated nanomaterials offer new opportunities for precise drug delivery and disease-specific targeting, which represent a versatile platform for targeted therapy in AD.

Usp14 deficiency removes α-synuclein by regulating S100A8/A9 in Parkinson's disease

Ubiquitin-proteasome system dysfunction triggers α-synuclein aggregation, a hallmark of neurodegenerative diseases, such as Parkinson's disease (PD). However, the crosstalk between deubiquitinating enzyme (DUBs) and α-synuclein pathology remains unclear. In this study, we observed a decrease in the level of ubiquitin-specific protease 14 (USP14), a DUB, in the cerebrospinal fluid (CSF) of PD patients, particularly females. Moreover, CSF USP14 exhibited a dual correlation with α-synuclein in male and female PD patients. To investigate the impact of USP14 deficiency, we crossed USP14 heterozygous mouse (USP14+/-) with transgenic A53T PD mouse (A53T-Tg) or injected adeno-associated virus (AAV) carrying human α-synuclein (AAV-hα-Syn) in USP14+/- mice. We found that Usp14 deficiency improved the behavioral abnormities and pathological α-synuclein deposition in female A53T-Tg or AAV-hα-Syn mice. Additionally, Usp14 inactivation attenuates the pro-inflammatory response in female AAV-hα-Syn mice, whereas Usp14 inactivation demonstrated opposite effects in male AAV-hα-Syn mice. Mechanistically, the heterodimeric protein S100A8/A9 may be the downstream target of Usp14 deficiency in female mouse models of α-synucleinopathies. Furthermore, upregulated S100A8/A9 was responsible for α-synuclein degradation by autophagy and the suppression of the pro-inflammatory response in microglia after Usp14 knockdown. Consequently, our study suggests that USP14 could serve as a novel therapeutic target in PD.

Biomimetic Nanovesicles as a Dual Gene Delivery System for the Synergistic Gene Therapy of Alzheimer's Disease

The association between dysfunctional microglia and amyloid-β (Aβ) is a fundamental pathological event and increases the speed of Alzheimer's disease (AD). Additionally, the pathogenesis of AD is intricate and a single drug may not be enough to achieve a satisfactory therapeutic outcome. Herein, we reported a facile and effective gene therapy strategy for the modulation of microglia function and intervention of Aβ anabolism by ROS-responsive biomimetic exosome-liposome hybrid nanovesicles (designated as TSEL). The biomimetic nanovesicles codelivery β-site amyloid precursor protein cleaving enzyme-1 (BACE1) siRNA (siBACE1) and TREM2 plasmid (pTREM2) gene drug efficiently penetrate the blood-brain barrier and enhance the drug accumulation at AD lesions with the help of exosomes homing ability and angiopep-2 peptides. Specifically, an upregulation of TREM2 expression can reprogram microglia from a pro-inflammatory M1 phenotype to an anti-inflammatory M2 phenotype while also restoring its capacity to phagocytose Aβ and its nerve repair function. In addition, siRNA reduces the production of Aβ plaques at the source by knocking out the BACE1 gene, which is expected to further enhance the therapeutic effect of AD. The in vivo study suggests that TSEL through the synergistic effect of two gene drugs can ameliorate APP/PS1 mice cognitive impairment by regulating the activated microglial phenotype, reducing the accumulation of Aβ, and preventing the retriggering of neuroinflammation. This strategy employs biomimetic nanovesicles for the delivery of dual nucleic acids, achieving synergistic gene therapy for AD, thus offering more options for the treatment of AD.

Schisandrin A Alleviates Spatial Learning and Memory Impairment in Diabetic Rats by Inhibiting Inflammatory Response and Through Modulation of the PI3K/AKT Pathway

Clinical and epidemiological research shows that people with diabetes mellitus frequently experience diabetic cognitive impairment. Schisandrin A (SchA), one of the lignans found in the dried fruit of Schisandra chinensis, has a variety of pharmacological effects on immune system control, apoptosis suppression, anti-oxidation and anti-inflammation. The goal of the current investigation was to clarify the probable neuro-protective effects of SchA against streptozotocin-induced diabetes deficiencies of the spatial learning and memory in rats. The outcomes show that SchA therapy effectively improved impaired glucose tolerance, fasting blood glucose level and serum insulin level in diabetic rats. Additionally, in the Morris water maze test, diabetic rats showed deficits in spatial learning and memory that were ameliorated by SchA treatment. Moreover, giving diabetic rats SchA reduced damage to the hippocampus structure and increased the production of synaptic proteins. Further research revealed that SchA therapy reduced diabetic-induced hippocampus neuron damage and the generation of Aβ, as demonstrated by the upregulated phosphorylation levels of insulin signaling pathway connected proteins and by the decreased expression levels of inflammatory-related factors. Collectively, these results suggested that SchA could improve diabetes-related impairments in spatial learning and memory, presumably by reducing inflammatory responses and regulating the insulin signaling system.

Revitalizing Ancient Mitochondria with Nano-Strategies: Mitochondria-Remedying Nanodrugs Concentrate on Disease Control

Mitochondria, widely known as the energy factories of eukaryotic cells, have a myriad of vital functions across diverse cellular processes. Dysfunctions within mitochondria serve as catalysts for various diseases, prompting widespread cellular demise. Mounting research on remedying damaged mitochondria indicates that mitochondria constitute a valuable target for therapeutic intervention against diseases. But the less clinical practice and lower recovery rate imply the limitation of traditional drugs, which need a further breakthrough. Nanotechnology has approached favorable regiospecific biodistribution and high efficacy by capitalizing on excellent nanomaterials and targeting drug delivery. Mitochondria-remedying nanodrugs have achieved ideal therapeutic effects. This review elucidates the significance of mitochondria in various cells and organs, while also compiling mortality data for related diseases. Correspondingly, nanodrug-mediate therapeutic strategies and applicable mitochondria-remedying nanodrugs in disease are detailed, with a full understanding of the roles of mitochondria dysfunction and the advantages of nanodrugs. In addition, the future challenges and directions are widely discussed. In conclusion, this review provides comprehensive insights into the design and development of mitochondria-remedying nanodrugs, aiming to help scientists who desire to extend their research fields and engage in this interdisciplinary subject.

Saikosaponin F ameliorates depression-associated dry eye disease by inhibiting TRIM8-induced TAK1 ubiquitination

AIMS

Saikosaponin F (SsF) is one of the major active ingredients of Radix Bupleuri, an herb widely used in the treatment of depression. Studies have shown that dry eye disease often occurs together with depression. The aim of this study is to investigate whether SsF can improve depression-associated dry eye disease and explore the underlying mechanism.

METHODS

Behavioral test was used to verify the effect of SsF on CUMS-induced depression-like behaviors in mice. Corneal fluorescein staining, phenol red cotton thread test and periodic acid-Schiff (PAS) staining were used to observe the effect of SsF on depression-associated dry eye disease. Western blot (WB) was performed to observe the expression of TAK1 protein and key proteins of NF-κB and MAPK (P38) inflammatory pathways in the hippocampus and cornea. Immunohistochemical staining was used to observe the expression of microglia, and immunoprecipitation was used to observe K63-linked TAK1 ubiquitination. Subsequently, we constructed a viral vector sh-TAK1 to silence TAK1 protein to verify whether SsF exerted its therapeutic effect based on TAK1. The expression of inflammatory factors such as IL-1β, TNF-α and IL-18 in hippocampus and cornea were detected by ELISA. Overexpression of TRIM8 (OE-TRIM8) by viral vector was used to verify whether SsF improved depression-associated dry eye disease based on TRIM8.

RESULTS

SsF treatment significantly improved the depression-like behavior, increased tear production and restored corneal injury in depression-related dry eye model mice. SsF treatment downregulated TAK1 expression and TRIM8-induced K63-linked TAK1 polyubiquitination, while inhibiting the activation of NF-κB and MAPK (P38) inflammatory pathways and microglial expression. In addition, selective inhibition of TAK1 expression ameliorated depression-associated dry eye disease, while overexpression of TRIM8 attenuated the therapeutic effect of SsF on depression-associated dry eye disease.

CONCLUSION

SsF inhibited the polyubiquitination of TAK1 by acting on TRIM8, resulting in the downregulation of TAK1 expression, inhibition of inflammatory response, and improvement of CUMS-induced depression-associated dry eye disease.

Gasotransmitter nitric oxide imaging in Alzheimer's disease and glioblastoma with diamino-cyclic-metalloiridium phosphorescence probes

Nitric Oxide (NO), a significant gasotransmitter in biological systems, plays a crucial role in neurological diseases and cancer. Currently, there is a lack of effective methods for rapidly and sensitively identifying NO and elucidating its relationship with neurological diseases. Novel diamino-cyclic-metalloiridium phosphorescence probes, Ir-CDA and Ir-BDA, have been designed to visualize the gasotransmitter NO in Alzheimer's disease (AD) and glioblastoma (GBM). Ir-CDA and Ir-BDA utilize iridium (III) as the central ion and incorporate a diamino group as a ligand. The interaction between the diamino structure and NO leads to the formation of a three-nitrogen five-membered ring structure, which opens up phosphorescence. The two probes can selectively bind to NO and offer low detection limits. Additionally, Ir-BDA/Ir-CDA can image NO in brain cancer cell models, neuroinflammatory models, and AD cell models. Furthermore, the NO content in fresh brain sections from AD mice was considerably higher than that in wild-type (WT) mice. Consequently, it is plausible that NO is generated in significant quantities around cells hosting larger Aβ deposits, gradually diffusing throughout the entire brain region. Furthermore, we posit that this phenomenon is a key factor contributing to the higher brain NO content in AD mice compared to that in WT mice. This discovery offers novel insights into the diagnosis and treatment of AD.

Association of vitamin B2 intake with cognitive performance in older adults: a cross-sectional study

BACKGROUND

To scrutinize the relationship between vitamin B2 consumption and cognitive function based on the NHANES database.

METHODS

This cross-sectional study included eligible older adults from the NHANES 2011-2014. Vitamin B2 intake was determined from dietary interview data for two 24-h periods. Cognitive function was evaluated through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). The regression analyses were used to evaluate the association of vitamin B2 intake with cognitive performance. Stratified analyses based on gender, race, and body mass index (BMI) were conducted.

RESULTS

Higher vitamin B2 intake was correlated with higher scores on each test. As compared to the lowest quartile, the highest quartile of vitamin B2 intake was related to a 45.1-fold increase (P = 0.004) on the DSST test sores. Moreover, those who were males, non-Hispanic whites, or had a BMI of 18.5 to 30 kg/m2 had a stronger relationship between total vitamin B2 consumption and cognitive function.

CONCLUSION

It's possible that older persons who consume more vitamin B2 have enhanced performance in some areas of cognitive function. To determine the causal link between vitamin B2 consumption and cognitive performance, further long-term research is required.

Nanomaterial payload delivery to central nervous system glia for neural protection and repair

Central nervous system (CNS) glia, including astrocytes, microglia, and oligodendrocytes, play prominent roles in traumatic injury and degenerative disorders. Due to their importance, active pharmaceutical ingredients (APIs) are being developed to modulate CNS glia in order to improve outcomes in traumatic injury and disease. While many of these APIs show promise in vitro, the majority of APIs that are systemically delivered show little penetration through the blood-brain barrier (BBB) or blood-spinal cord barrier (BSCB) and into the CNS, rendering them ineffective. Novel nanomaterials are being developed to deliver APIs into the CNS to modulate glial responses and improve outcomes in injury and disease. Nanomaterials are attractive options as therapies for central nervous system protection and repair in degenerative disorders and traumatic injury due to their intrinsic capabilities in API delivery. Nanomaterials can improve API accumulation in the CNS by increasing permeation through the BBB of systemically delivered APIs, extending the timeline of API release, and interacting biophysically with CNS cell populations due to their mechanical properties and nanoscale architectures. In this review, we present the recent advances in the fields of both locally implanted nanomaterials and systemically administered nanoparticles developed for the delivery of APIs to the CNS that modulate glial activity as a strategy to improve outcomes in traumatic injury and disease. We identify current research gaps and discuss potential developments in the field that will continue to translate the use of glia-targeting nanomaterials to the clinic.

Dietary intake of α-ketoglutarate ameliorates α-synuclein pathology in mouse models of Parkinson's disease

Parkinson's disease (PD) is a progressive movement disorder characterized by dopaminergic (DA) neuron degeneration and the existence of Lewy bodies formed by misfolded α-synuclein. Emerging evidence supports the benefits of dietary interventions in PD due to their safety and practicality. Previously, dietary intake of α-ketoglutarate (AKG) was proved to extend the lifespan of various species and protect mice from frailty. However, the mechanism of dietary AKG's effects in PD remains undetermined. In the present study, we report that an AKG-based diet significantly ameliorated α-synuclein pathology, and rescued DA neuron degeneration and impaired DA synapses in adeno-associated virus (AAV)-loaded human α-synuclein mice and transgenic A53T α-synuclein (A53T α-Syn) mice. Moreover, AKG diet increased nigral docosahexaenoic acid (DHA) levels and DHA supplementation reproduced the anti-α-synuclein effects in the PD mouse model. Our study reveals that AKG and DHA induced microglia to phagocytose and degrade α-synuclein via promoting C1q and suppressed pro-inflammatory reactions. Furthermore, results indicate that modulating gut polyunsaturated fatty acid metabolism and microbiota Lachnospiraceae_NK4A136_group in the gut-brain axis may underlie AKG's benefits in treating α-synucleinopathy in mice. Together, our findings propose that dietary intake of AKG is a feasible and promising therapeutic approach for PD.

Cntnap4 partial deficiency exacerbates α-synuclein pathology through astrocyte-microglia C3-C3aR pathway

Parkinson's disease (PD) is the most common progressive neurodegenerative movement disorder, which is characterized by dopaminergic (DA) neuron death and the aggregation of neurotoxic α-synuclein. Cntnap4, a risk gene of autism, has been implicated to participate in PD pathogenesis. Here we showed Cntnap4 lacking exacerbates α-synuclein pathology, nigrostriatal DA neuron degeneration and motor impairment, induced by injection of adeno-associated viral vector (AAV)-mediated human α-synuclein overexpression (AAV-hα-Syn). This scenario was further validated in A53T α-synuclein transgenic mice injected with AAV-Cntnap4 shRNA. Mechanistically, α-synuclein derived from damaged DA neuron stimulates astrocytes to release complement C3, activating microglial C3a receptor (C3aR), which in turn triggers microglia to secrete complement C1q and pro-inflammatory cytokines. Thus, the astrocyte-microglia crosstalk further drives DA neuron death and motor dysfunction in PD. Furthermore, we showed that in vivo depletion of microglia and microglial targeted delivery of a novel C3aR antagonist (SB290157) rescue the aggravated α-synuclein pathology resulting from Cntnap4 lacking. Together, our results indicate that Cntnap4 plays a key role in α-synuclein pathogenesis by regulating glial crosstalk and may be a potential target for PD treatment.