Sodium rutin ameliorates Alzheimer's disease-like pathology by enhancing microglial amyloid-β clearance

Hypercholesterolemia drives microglial dysfunction and weakens response to amyloid plaques

Hypercholesterolemia is a recognized comorbidity of Alzheimer's disease (AD), yet its mechanistic connection to AD pathology, particularly its impact on microglial function and amyloid-beta (Aβ) dynamics remains unclear. To investigate this, we utilized the APPNL-G-F (AK) mouse model, which develops robust Aβ pathology, and the APPNL-G-F;LDLR-/- (ALKO) model, which combines Aβ pathology with LDL receptor deficiency to induce hypercholesterolemia under a Western diet (WD). These models were designed to study the combined effects of genetic predisposition and dietary factors on AD progression. At six months of age, mice were maintained on a control diet or switched to a WD for two months to induce hypercholesterolemia. Our findings demonstrate that hypercholesterolemia suppresses microglial responses to Aβ plaques, evidenced by reduced clustering and activation of microglia around plaques. The combination of WD and LDLR deficiency synergistically diminished the expression of disease-associated microglia markers, resulting in reduced Aβ plaque compactness. Mechanistically, RNA sequencing revealed hypercholesterolemia impaired microglial mitochondrial function, reduced protein synthesis, and heightened neuroinflammation. Lipidomic profiling revealed significant changes in the microglial lipidome, including elevated ceramides, hexosylceramides, and lysophosphatidylcholine, along with reduced N-acylethanolamines, reflecting a pro-inflammatory and metabolically stressed microglial state. Behavioral analyses further revealed that both WD and LDLR deficiency independently and synergistically impaired cognitive performance and increased anxiety-like behaviors in AD mice. Together, this study highlights the role of hypercholesterolemia in exacerbating AD pathology by disrupting microglial function, altering lipid metabolism, and impairing cognitive function, and suggests that pharmacological management of hypercholesterolemia could slow AD progression.

Glycosyltransferases: Pioneering roles in agriculture and medicine

Glycosyltransferases (GTs) belong to a diverse family of enzymes that catalyze the transfer of sugar moieties from activated donor sugars to specific acceptors, thus playing a crucial roles in various biological processes. This review explores the pioneering roles of uridine diphosphate-dependent GTs (UGTs), which use uridine diphosphate glucose as donors. UGTs have also been extensively studied in agricultural and medical fields, emphasizing their potential to revolutionize these sectors. In the agricultural sector, the genetic engineering of UGTs has demonstrate potential in developing crops with enhanced stress tolerance, regulated plant development, and increased resistance to pests and diseases. These advancements not only contribute to sustainable farming practices but also address global food security challenges by facilitating the production of more resilient plant varieties. Furthermore, UGTs facilitate the synthesis of complex carbohydrates and glycoconjugates in plants, which are critical for developing drugs and therapeutic strategies targeting various ailments, including cancer and infectious diseases. Thus, this review explored the functions and synthesis methods of flavonoid glycosides, terpenoid glycosides, and polyketosides in detail. Moreover, owing to the functional diversity of UGTs, numerous research methods were reviewed, and novel, more valuable UGTs will be obtained. In summary, this study synthesizes the current research findings and discusses future perspectives to underscore the transgenic technology and synthetic biological impact of UGTs on agriculture and medicine and bridge the gap between fundamental science and practical applications.

Identification and validation of biomarkers in Alzheimer's disease based on machine learning algorithms and single-cell sequencing analysis

OBJECTIVE

Alzheimer's disease (AD) is a complicated neurodegenerative disease with unknown pathogenesis. Identifying possible diagnostic markers of AD is essential to elucidate its mechanisms and facilitate diagnosis.

METHODS

A total of 295 samples (153 AD and 142 normal) were analyzed from two datasets (GSE122063 and GSE132903) in the Gene Express Omnibus (GEO) database. Differentially expressed genes (DEGs) between groups were identified and dimensionality reduction was applied to identify feature genes (key genes) using three algorithms of machine learning including least absolute shrinkage and selection operator (LASSO), support vector machine-recursive feature elimination (SVM-RFE), and Random forest (RF). In addition, we obtained sample data from single-cell RNA datasets GSE157827, GSE167490, and GSE174367 to classify cells into different types and examined changes in gene expression and their correlation with AD progression. Immunofluorescence assay was used to verify the expression of key genes in animal experiments.

RESULTS

To identify diagnostic genes associated with AD, we analyzed two datasets and identified 379 DEGs which might be related to the onset of AD, and 115 of them were up-regulated and 264 down-regulated. Three algorithms of machine learning were adopted to reduce the dimensions of these DEGs and finally six core DEGs CD86, SCG3, VGF, PRKCG, SPP1, and TPI1 of AD were identified. Diagnostic analyses showed that SCG3 was substantially down-regulated in the AD group, and its AUC was higher in both the training and validation sets (0.845, 0.927, and 0.917, respectively). Transcriptome sequencing results further revealed that SCG3 expression was down-regulated in multiple cell types in the AD group and SCG3 expression in the hippocampus was found significantly reduced in the AD group.

CONCLUSIONS

This study systematically identified and validated the potential of SCG3 as an early diagnostic biomarker for AD through several technical strategies. The findings provided new biomarkers for early detection of AD and laid a foundation for future clinical applications.

PKM2-mediated metabolic reprogramming of microglia in neuroinflammation

Microglia, the resident immune cells of the central nervous system, undergo metabolic reprogramming during neuroinflammation, playing a crucial role in the pathogenesis of neurological disorders such as Parkinson's disease. This review focuses on Pyruvate Kinase M2 (PKM2), a key glycolytic enzyme, and its impact on microglial metabolic reprogramming and subsequent neuroinflammation. We explore the regulatory mechanisms governing PKM2 activity, its influence on microglial activation and immune responses, and its contribution to the progression of various neurological diseases. Finally, we highlight the therapeutic potential of targeting PKM2 as a novel strategy for treating neuroinflammation-driven neurological disorders. This review provides insights into the molecular mechanisms of PKM2 in neuroinflammation, aiming to inform the development of future therapeutic interventions.

RVG engineered extracellular vesicles-transmitted miR-137 improves autism by modulating glucose metabolism and neuroinflammation

Autism spectrum disorder (ASD) is a prevalent neurodevelopmental disorder. The microglia activation is a hallmark of ASD, which involves increased glycolysis. Elevated glycolysis regardless of oxygen availability, known as "Warburg effect", is crucial to pathogenesis in neuropsychiatric disorders. Psychiatric risk gene MIR137 plays an important role in neurogenesis and neuronal maturation, but the impact on neuroinflammation and glucose metabolism remains obscure. Extracellular vesicles (EVs) can delivery miR-137 crossing the blood-brain barrier. Meanwhile, EVs can help miR-137 avoid being rapidly degraded by endogenous nucleases. Here, after first detecting miR-137 decreased both in the peripheral blood of individuals with ASD and the serum and cerebellum of BTBR mice, we demonstrated that microglia activation, the level of lactate and key enzymes (HK2, PKM2 and LDHA) involved in glycolysis were increased significantly in BTBR mice. Of particular note, EVs engineered by rabies virus glycoprotein (RVG) could promote the miR-137 (RVG-miR137-EVs) targeted to the brain accurately, and alleviated autism-like behaviors. Pro-inflammatory activation of BTBR mice was considerably inhibited by RVG-miR137-EVs via tail vein administration, accompanied by decreased lactate production. Mechanically, these effects were attributed to TLR4, the key target gene, which was regulated by miR-137. The TLR4/NF-κB pathway was inhibited, subsequently reducing HIF-1α and repressing the transcription of HK2, PKM2 and LDHA involved in glycolysis. Pharmacological inhibition of glycolysis and TLR4 attenuated microglial activation and lactate production, ultimately improved autism-like behaviors of BTBR mice. In conclusion, our results indicated that miR-137 could alleviate autism-like behaviors by HIF-1α-mediated adaptive metabolic changes in glycolysis and neuroinflammation.

Rutin ameliorates stress-induced blood‒brain barrier dysfunction and cognitive decline via the endothelial HDAC1‒Claudin-5 axis

BACKGROUND

Emerging evidence suggests that chronic stress compromises blood‒brain barrier (BBB) integrity by disrupting brain microvascular endothelial cells (BMECs), contributing to the development of cognitive impairments. Thus, targeting the BBB is expected to be a promising treatment strategy. The biological function of rutin has been investigated in neurological disorders; however, its regulatory role in stress-induced BBB damage and cognitive decline and the underlying mechanisms remain elusive.

METHODS

In a chronic unpredictable mild stress (CUMS) mouse model, a fluorescent dye assay and behavioral tests, including a novel object recognition test and Morris water maze, were performed to evaluate the protective effects of rutin on BBB integrity and cognition. The effects of rutin on BMEC function were also investigated in hCMEC/D3 cells (a human brain microvascular endothelial cell line) in vitro. Furthermore, the molecular mechanisms by which rutin restores BBB endothelium dysfunction were explored via RNA-seq, quantitative real-time PCR, western blotting, immunofluorescence and chromatin immunoprecipitation. Finally, biotinylated tumor necrosis factor-α (TNF-α) was employed to test the influence of rutin on the ability of circulating TNF-α to cross the BBB.

RESULTS

We identified that rutin attenuated BBB hyperpermeability and cognitive impairment caused by the 8-week CUMS procedure. Moreover, rutin promoted the proliferation, migration and angiogenesis ability of BMECs, and the integrity of the cellular monolayer through positively regulating the expression of genes involved. Furthermore, rutin impeded histone deacetylase 1 (HDAC1) recruitment and stabilized H3K27ac to increase Claudin-5 protein levels. Ultimately, normalization of the hippocampal HDAC1‒Claudin-5 axis by rutin blocked the infiltration of circulating TNF-α into the brain parenchyma and alleviated neuroinflammation.

CONCLUSIONS

This work establishes a protective role of rutin in regulating BMEC function and BBB integrity, and reveals that rutin is a potential drug candidate for curing chronic stress-induced cognitive deficits.

Alzheimer's Disease-Derived Outer Membrane Vesicles Exacerbate Cognitive Dysfunction, Modulate the Gut Microbiome, and Increase Neuroinflammation and Amyloid-β Production

Although our understanding of the molecular biology of Alzheimer's disease (AD) continues to improve, the etiology of the disease, particularly the involvement of gut microbiota disturbances, remains a challenge. Outer membrane vesicles (OMVs) play a key role in central nervous system diseases, but the impact of OMVs on AD progression remains unclear. In this study, we hypothesized that AD-derived OMVs (OMVsAD) were a risk factor in AD pathology. To test our hypothesis, young APP/PS1 mice (AD mice) were given OMVsAD by gavage. Young AD mice were euthanized 120 days after gavage to assess the intestinal barrier, gut microbiota diversity, mediators of neuroinflammation, glial markers, amyloid burden, and short-chain fatty acid (SCFA) levels. Our results showed that OMVsAD accelerated cognitive dysfunction after 120 days of intragastric administration. Morris water maze experiment and new object recognition test showed that OMVsAD caused significantly poorer spatial ability learning and memory of the AD mice. We observed the OMVsAD-treated APP/PS1 mice display OMVs disrupting the intestinal barrier compared with controls of normal human-derived OMVs. Compared with the OMVsHC group, claudin-5 and ZO-1 related to the intestinal barrier were significantly downregulated in the OMVsAD group. The OMVsAD activate microglia in the cerebral cortex and hippocampus of AD mice, and the levels of IL-1β, IL-6, TNF-α, and NF-Κb were upregulated. We also found that OMVsAD increased Aβ production. 16S rRNA sequencing showed that OMVsAD negatively regulated the α- and β-diversity index of intestinal flora and reduced the levels of SCFA. OMVsAD may change the intestinal flora of young AD, damage the intestinal mucosa and blood-brain barrier, and accelerate AD neuropathological damage.

Novel application of cycloastragenol target microglia for the treatment of Alzheimer's disease: Evidence from single-cell analysis, network pharmacology and experimental assessment

BACKGROUND

Cycloastragenol (CAG), a compound extracted from Astragalus, is known for its telomerase activation and anti-inflammatory, antioxidant properties. However, its potential pharmacological effects on Alzheimer's disease (AD) remain unclear.

PURPOSE

This study aimed to explore potential targets and molecular mechanisms for the role of CAG in alzheimer's disease (AD) treatment.

METHODS

CAG was administered to 5 × FAD mice. The senescent cell count was verified by senescence-associated β-galactosidase (SA-β-gal) staining. The impact of CAG on microglial phagocytosis was assessed by in vitro and in vivo assays. The potential targets of CAG were identified by network pharmacology and single-nucleus RNA sequencing (snRNA-seq). The underlying mechanism was validated by molecular docking, surface plasmon resonance (SPR) and western blotting.

RESULTS

CAG effectively ameliorated cognitive impairments and microglial senescence in 5 × FAD mice. In vivo and in vitro experiments revealed that CAG modulated microglial phagocytic activity and reduced hippocampal Aβ deposition The analysis of single-nucleus RNA sequencing data of AD patients reported 13 microglial targets for AD intervention. Phosphodiesterase 4B (PDE4B) was identified as the target through which CAG regulated microglial activity by utilizing network pharmacology, molecular docking and SPR. Western blotting revealed that the PDE4B/CREB/BDNF pathway may mediate the regulatory effect of CAG.

CONCLUSION

CAG can enhance microglial phagocytosis and alleviate memory dysfunction and amyloid plaque pathology. Our findings suggest that CAG may regulate microglial function through its interaction with PDE4B, providing a novel therapeutic strategy for AD.

Quercetin protects against neuronal toxicity by activating the PI3K/Akt/GSK-3β pathway in vivo models of MPTP-induced Parkinson's disease

BACKGROUND

Quercetin is a flavonoid commonly found in various fruits, vegetables, and grains. Studies have demonstrated that quercetin may help protect neuronal cells from damage caused by neurotoxins associated with Parkinson's disease, however, the underlying mechanism remains unclear.

AIM

The current study aimed to investigate the neuroprotective effects of quercetin in MPTP-induced Parkinson's disease mouse models and elucidate its mechanistic role in modulating the PI3K/Akt/GSK-3β signaling pathway.

MATERIALS AND METHODS

Male C57BL/6 mice were divided into control, MPTP, quercetin, and MPTP + quercetin groups. The protective effects of quercetin on Parkinson's disease in mice were evaluated using animal behaviour analysis, histopathological examination, and immunofluorescence staining. Subsequently, network pharmacology was utilized to determine the primary target sites of quercetin in Parkinson's disease. Finally, western blotting and molecular docking techniques were applied to validate the identified targets.

RESULTS

Quercetin significantly improved motor deficits in MPTP mice, reduced neuronal atrophy, and preserved TH+ dopaminergic neurons. Western blotting analysis revealed quercetin upregulated anti-inflammatory IL-10 (p < 0.01) and TGF-β (p < 0.01) while suppressing pro-inflammatory IL-1β (p < 0.01) and iNOS (p < 0.01). It activated the PI3K/Akt/GSK-3β pathway by increasing phosphorylation of PI3K (p < 0.01), Akt (p < 0.01), and GSK-3β (p < 0.01). Quercetin also elevated anti-apoptotic Bcl-2 (p < 0.01) and reduced pro-apoptotic Bax (p < 0.01) and Caspase-9 (p < 0.01). Molecular docking confirmed strong binding between quercetin and PI3K/Akt/GSK-3β (binding energies: -6.44 to -5.24 kcal/mol).

CONCLUSION

Quercetin alleviates Parkinson's disease pathology by inhibiting neuroinflammation, reducing apoptosis, and activating the PI3K/Akt/GSK-3β pathway. These findings underscore its potential as a multi-target therapeutic agent for Parkinson's disease.

Lycium barbarum L.: a potential botanical drug for preventing and treating retinal cell apoptosis

Retinal cell apoptosis is the primary pathological process in many retinal diseases, including retinitis pigmentosa and age-related macular degeneration, which can cause severe visual impairment and blindness. Lycium barbarum L., a traditional Chinese medicinal botanical drug, has a long history and extensive application in ophthalmic disease prevention and treatment. This study systematically reviewed the key active metabolites in L. barbarum L., including L. barbarum polysaccharides, carotenoids, and flavonoids, that exert retinal protective effects. A comprehensive analysis of the pharmacological effects and underlying molecular mechanisms of L. barbarum L. and its active metabolites in the prevention and treatment of retinal cell apoptosis, including essential aspects such as antioxidant activity, anti-inflammatory properties, autophagy regulation, and mitochondrial function preservation, is essential to establish a comprehensive and solid theoretical basis for further investigation of the medicinal value of L. barbarum L. in ophthalmology and provide a reference for future research directions.

Glucose Metabolic Reprogramming in Microglia: Implications for Neurodegenerative Diseases and Targeted Therapy

As intrinsic immune cells in the central nervous system, microglia play a crucial role in maintaining brain homeostasis. Microglia can transition from homeostasis to various responsive states in reaction to different external stimuli, undergoing corresponding alterations in glucose metabolism. In neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), microglial glucose metabolic reprogramming is widespread. This reprogramming leads to changes in microglial function, exacerbating neuroinflammation and the accumulation of pathological products, thereby driving the progression of neurodegeneration. This review summarizes the specific alterations in glucose metabolism within microglia in AD, PD, ALS, and MS, as well as the corresponding treatments aimed at reprogramming glucose metabolism. Compounds that inhibit key glycolytic enzymes like hexokinase 2 (HK2) and pyruvate kinase M2 (PKM2), or activate regulators of energy metabolism such as AMP-activated protein kinase (AMPK), have shown significant potential in the treatment of various neurodegenerative diseases. However, current research faces numerous challenges, including side effects and blood-brain barrier (BBB) penetration of compounds. Screening relevant drugs from natural products, especially flavonoids, is a reliable approach. On the one hand, longtime herbal medical practices provide a certain degree of assurance regarding clinical safety, and their chemical properties contribute to effective BBB permeability. On the other hand, the concurrent anti-tumor and anti-neuroinflammatory activities of flavonoids suggest that regulation of glucose metabolism reprogramming might be a potential common mechanism of action. Notably, considering the dynamic nature of microglial metabolism, there is an urgent need to develop technologies for real-time monitoring of glucose metabolism processes, which would significantly advance research in this field.

A Self-Reinforced "Microglia Energy Modulator" for Synergistic Amyloid-β Clearance in Alzheimer's Disease Model

Microglial phagocytosis is a highly energy-consuming process that plays critical roles in clearing neurotoxic amyloid-β (Aβ) in Alzheimer's disease (AD). However, microglial metabolism is defective overall in AD, thereby undermining microglial phagocytic functions. Herein, we repurpose the existing antineoplastic drug lonidamine (LND) conjugated with hollow mesoporous Prussian blue (HMPB) as a "microglial energy modulator" (termed LND@HMPB-T7) for safe and synergistic Aβ clearance. The modified blood-brain barrier penetrating heptapeptide (T7) enables efficient transport of LND@HMPB-T7 to the AD brain. LND in LND@HMPB-T7 could fuel Aβ phagocytosis by stimulating microglial adenosine triphosphate (ATP) production, whereas HMPB with catalase and superoxide dismutase-mimicking activities substantially alleviates the mitochondrial side effects commonly associated with LND and thus further enhances ATP production. The synergism of LND and nanozyme affords a high microglial Aβ clearance efficacy without triggering mitochondrial dysfunction. In vivo experiments ascertain that LND@HMPB-T7 could synergistically promote phagocytic clearance of Aβ, relieve neuroinflammation and ameliorate cognitive function in AD mice. These findings indicate that LND@HMPB-T7 holds tremendous clinical potential as a repurposed drug for AD treatment.

Gallic acid and loganic acid attenuate amyloid-β oligomer-induced microglia damage via NF-КB signaling pathway

Amyloid β peptide (Aβ) induces neurodegeneration in the early stage of Alzheimer's disease (AD), resulting in neuroinflammation, oxidative damage, and mitochondrial impaired function. These reactions were closely associated with the pathological changes of brain microglia. Therefore, it was crucial to investigate the precise process of neuroinflammation induced by Aβ in microglia and discover therapies to alleviate its harmful consequences. This study evaluated the toxicity detection of primary microglia generated by Aβ42 ADDL. identification of inflammatory markers, measurement of ROS, and assessment of mitochondrial energy metabolism, mitochondrial membrane potential damage and mitochondrial ROS to evaluate the reparative properties of natural small molecule compounds Gallic acid and Loganic acid on primary mouse microglia. The findings indicated that Gallic acid and Loganic acid exhibited diverse reparative effects on impaired microglia. Thus, it can be provisionally predicted that Aβ42 ADDL affects microglia and promotes modifications in the NF-кB signaling pathway. Gallic acid and Loganic acid were expected to initially restore the NF-кB signaling pathway, leading to a reduction in M1-microglia and an elevation in M2-microglia, thereby decreasing various inflammatory factors and increasing anti-inflammatory factors. The mitochondrial metabolism, mitochondrial membrane potential, and mitochondrial ROS of primary microglia were restored, leading to a reduction in neuroinflammation.

Therapeutic potential of rutin in premenstrual depression: evidence from in vivo and in vitro studies

Introduction

Premenstrual dysphoric disorder (PMDD) is a cyclical mood disorder that severely affects the daily life of women of reproductive age. Most of the medications being used clinically have limitations such as low efficacy, side effects, and high cost, so there is an urgent need to discover safer and more effective medications. Rutin is a natural flavonol glycoside with various pharmacological properties including antidepressant. The study of the efficacy and mechanism of action of rutin in PMDD-depressed subtype model rats plays an important role in the discovery of new drugs for the treatment of PMDD.

Methods

Binding of rutin to gamma-aminobutyric acid type A receptors (GABAA receptors) was probed using molecular docking, microscale thermophoresis, radioactive receptor ligand binding assay and cell membrane clamp experiment. Behavioral tests in mice were performed to screen the optimal dose of rutin. Behavioral tests were performed to evaluate the effects of rutin on depressed mood, memory impairment, and social impairment in PMDD-depressed subtype model rats. HE staining and Golgi staining were performed to observe the neuronal damage in rat hippocampus. UHPLC-MS/MS targeted metabolomics was performed to detect the changes of neurotransmitter content in rat hippocampus. PCR array to detect the effect of rutin on mRNA expression of GABAA receptor partial subunits in rat hippocampus.

Results

The docking score of rutin with the GABAA receptor benzodiazepine site was -11.442 and the gliding score was -11.470. The Kd of rutin with the GABAA receptor (α1β2γ2) was 1.17 ± 0.89 μM. Rutin competed with [H3]-flunitrazepam for the GABAA receptor benzodiazepine site and inhibited the inward flow of chloride ions (P < 0.05). In PMDD-depressed subtype rats, rutin alleviated depressed mood, memory impairment and social impairment, ameliorated hippocampal neuronal damage and reduces gamma-aminobutyric acid (GABA) and acetylcholine (ACh) levels (P < 0.05). Moreover, we found that rutin did not affect the relative mRNA expression of GABAA receptor subunits in rat hippocampus.

Discussion

Overall, rutin alleviated depressed mood, memory impairment and social impairment in PMDD-depressed subtype rats, which may be related to binding to GABAA receptor benzodiazepine sites, inhibiting chloride ions inward flow, ameliorating hippocampal neuronal damage and reducing GABA and ACh levels. The results of this study provide an experimental basis and scientific evidence for the development of new drugs for the treatment of PMDD.

Neurotrophic factor-α1/carboxypeptidase E controls progression and reversal of Alzheimer's disease pathogenesis in mice

Background: Neurotrophic Factor-α1/Carboxypeptidase E (NF-α1/CPE) is a pivotal neuroprotective protein implicated in rescuing cognitive decline associated with Alzheimer's disease (AD). However, its direct role in AD pathogenesis remains unexplored. Methods: We utilized the Cre/LoxP system to diminish NF-α1/CPE expression, and employed AAV-mediated overexpression of NF-α1/CPE. Results: NF-α1/CPE expression was significantly down-regulated in advanced stages of AD and with age in 5xFAD mice. Reduced NF-α1/CPE levels in the hippocampus of 5xFAD mice increased plaque burden, microglial cell count, disrupted synaptogenesis, and intensified cognitive impairments at 5 and 7 months. However, by 9 months, no further progression of detrimental effects was observed. Overexpression of NF-α1/CPE markedly decreased amyloid plaque accumulation, mitigated spatial memory deficits, and normalized hippocampal synaptogenesis and microglial anomalies across early and late stages of the disease. Conclusion: NF-α1/CPE is a critical regulator of AD pathogenesis, offering promising therapeutic potential for reducing amyloid beta deposition and toxicity in AD.

Microglia lactylation in relation to central nervous system diseases

The development of neurodegenerative diseases is closely related to the disruption of central nervous system homeostasis. Microglia, as innate immune cells, play important roles in the maintenance of central nervous system homeostasis, injury response, and neurodegenerative diseases. Lactate has been considered a metabolic waste product, but recent studies are revealing ever more of the physiological functions of lactate. Lactylation is an important pathway in lactate function and is involved in glycolysis-related functions, macrophage polarization, neuromodulation, and angiogenesis and has also been implicated in the development of various diseases. This review provides an overview of the lactate metabolic and homeostatic regulatory processes involved in microglia lactylation, histone versus non-histone lactylation, and therapeutic approaches targeting lactate. Finally, we summarize the current research on microglia lactylation in central nervous system diseases. A deeper understanding of the metabolic regulatory mechanisms of microglia lactylation will provide more options for the treatment of central nervous system diseases.

Accumulated BCAAs and BCKAs contribute to the HFD-induced deterioration of Alzheimer's disease via a dysfunctional TREM2-related reduction in microglial β-amyloid clearance

A high-fat diet (HFD) induces obesity and insulin resistance, which may exacerbate amyloid-β peptide (Aβ) pathology during Alzheimer's disease (AD) progression. Branched-chain amino acids (BCAAs) accumulate in obese or insulin-resistant patients and animal models. However, roles of accumulated BCAAs and their metabolites, branched-chain keto acids (BCKAs), in the HFD-induced deterioration of AD and the underlying mechanisms remains largely unclear. In this study, APPswe/PSEN1dE9 (APP/PS1) transgenic mice were fed a HFD for 6 months, and the BCAAs content of the HFD was adjusted to 200% or 50% to determine the effects of BCAAs. The HFD-fed APP/PS1 mice accumulated BCAAs and BCKAs in the serum and cortex, which was accompanied by more severe cognitive deficits and AD-related pathology. The additional or restricted intake of BCAAs aggravated or reversed these phenomena. Importantly, BCAAs and BCKAs repressed microglial phagocytosis of Aβ in vivo and in BV2 cells, which might be relevant for triggering receptor expressed on myeloid cells 2 (TREM2) dysfunction and autophagy deficiency. We found that BCAAs and BCKAs could bind to TREM2 in silico, in pure protein solutions and in the cellular environment. These molecules competed with Aβ for binding to TREM2 so that the response of TREM2 to Aβ was impaired. Moreover, BCAAs and BCKAs decreased TREM2 recycling in an mTOR-independent manner, which might also lead to TREM2 dysfunction. Our findings suggest that accumulated BCAAs and BCKAs contribute to the HFD-induced acceleration of AD progression through hypofunctional TREM2-mediated disturbances in Aβ clearance in microglia. Lowering BCAAs and BCKAs levels may become a potential dietary intervention for AD.

PFOS sub-chronic exposure selectively activates Aβ clearance pathway to improve the cognitive ability of AD mice

Perfluorooctane sulfonate (PFOS), an emerging persistent organic pollutant, has been controversial in its impact on cognitive functions. Our previous research has confirmed that the sub-chronic PFOS exposure leads to neuronal apoptosis in the cerebral cortex, impairing cognitive functions in normal mice. However, our current study presents a surprising finding: sub-chronic exposure to PFOS effectively reduces cognitive impairments in Alzheimer's disease (AD) mice and significantly retards the disease's progression. Our results indicate that PFOS exposure upregulates the expression level of insulin-degrading enzyme (IDE) in the prefrontal cortex (PFC) of AD mice, thereby selectively enhancing the amyloid-beta (Aβ) clearance pathway without affecting the Aβ production. Moreover, PFOS exposure inhibits microglial proliferation and reduces inflammatory cytokines levels in the PFC of AD mice, providing further supporting for the pivotal role of IDE in attenuating AD progression under PFOS exposure. Collectively, our study is the first to demonstrate that sub-chronic PFOS exposure can alleviates cognitive impairments in AD pathology, with the IDE-mediated Aβ clearance pathway potentially playing a critical role.

Hidden role of microglia during neurodegenerative disorders and neurocritical care: A mitochondrial perspective

The incidence of aging-related neurodegenerative disorders and neurocritical care diseases is increasing worldwide. Microglia, the main inflammatory cells in the brain, could be potential viable therapeutic targets for treating neurological diseases. Interestingly, mitochondrial functions, including energy metabolism, mitophagy and transfer, fission and fusion, and mitochondrial DNA expression, also change in activated microglia. Notably, mitochondria play an active and important role in the pathophysiology of neurodegenerative disorders and neurocritical care diseases. This review briefly summarizes the current knowledge on mitochondrial dysfunction in microglia in neurodegenerative disorders and neurocritical care diseases and comprehensively discusses the prospects of the application of neurological injury prevention and treatment targets by mitochondria.

Therapeutic implication of targeting mitochondrial drugs designed for efferocytosis dysfunction

Efferocytosis refers to the process by which phagocytes remove apoptotic cells and related apoptotic products. It is essential for the growth and development of the body, the repair of damaged or inflamed tissues, and the balance of the immune system. Damaged efferocytosis will cause a variety of chronic inflammation and immune system diseases. Many studies show that efferocytosis is a process mediated by mitochondria. Mitochondrial metabolism, mitochondrial dynamics, and communication between mitochondria and other organelles can all affect phagocytes' clearance of apoptotic cells. Therefore, targeting mitochondria to modulate phagocyte efferocytosis is an anticipated strategy to prevent and treat chronic inflammatory diseases and autoimmune diseases. In this review, we introduced the mechanism of efferocytosis and the pivoted role of mitochondria in efferocytosis. In addition, we focused on the therapeutic implication of drugs targeting mitochondria in diseases related to efferocytosis dysfunction.

Kaixinsan regulates neuronal mitochondrial homeostasis to improve the cognitive function of Alzheimer's disease by activating CaMKKβ-AMPK-PGC-1α signaling axis

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disease primarily characterized by cognitive impairments. With the intensification of population aging, AD has become a major health concern affecting the elderly. Kaixinsan, a classical traditional Chinese formula, consists of Ginseng Panax et Rhizoma, Polygalae Radix, Poria and Acori Tatarinowii Rhizoma, and is commonly used in clinical for treating memory decline. However, its mechanism remains unclear, which hinders its popularization and application.

METHOD

Morris water maze (MWM) was performed to evaluate the effect of Kaixinsan on improving learning and memory ability in SAMP8 (senescence-accelerated mouse prone 8, an AD model mice) mice. Nissl staining, TdT-mediated dUTP Nick End Labeling (TUNEL) and western blotting (Bax and Bcl-2) were used to confirm the effect of Kaixinsan on the neuronal structure and apoptosis of SAMP8 mice. Ultra performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS) was performed to identify the distribution components in brain tissue after administration of Kaixinsan extraction. Based on the identified brain distribution components, the mechanism of Kaixinsan improving the cognitive function was predicted by network pharmacology. Then, using HSP60 as a mitochondrial marker and RBFOX3 as a neuronal marker, immunofluorescence co-localization was used to confirm the effect of Kaixinsan on neuronal mitochondria quantity in SAMP8 mice. Western blotting was employed to access the expression of predicted proteins (AMPK, CaMKKβ, PGC-1α and HSP90) implicated in mitochondrial homeostasis. To further confirm the mechanism of Kaixinsan, SH-SY5Y cell injury model induced by amyloid β - protein fragment 25-35 (Aβ25-35) was replicated and the effect of Kaixinsan - containing serum on apoptosis in injured SH-SY5Y cells was investigated by flow cytometer. The expression level of apoptosis-associated proteins (Bax and Bcl-2) and mitochondrial homeostasis related proteins (AMPK, CaMKKβ, PGC-1α and HSP90) in the presence or absence of CaMKKβ inhibitor (STO-609) were compared.

RESULTS

The results indicate that Kaixinsan can improve the cognitive function of SAMP8 mice, alleviate the hippocampal tissue lesions and inhibit neuron apoptosis. Seventeen brain distribution components of Kaixinsan were identified. Based on the brain distribution components of Kaixinsan, the results of network pharmacology suggest that Kaixinsan may regulate mitochondrial homeostasis through the CaMKKβ-AMPK-PGC-1α signaling axis. In vivo experiments indicated that Kaixinsan could reverse neuronal mitochondrial loss in SAMP8 mice by upregulating CaMKKβ, AMPK, HSP90 and PGC-1α to promote mitochondrial biogenesis and increase the number of neuronal mitochondria. Additionally, the in vitro experiments demonstrated that Kaixinsan can inhibit apoptosis of Aβ25-35 injured SH-SY5Y cells and upregulate mitochondrial homeostasis-related proteins CaMKKβ, AMPK and PGC-1α. However, in addition to CaMKKβ inhibitors, the neuroprotective effect disappeared.

CONCLUSION

The results indicate that Kaixinsan can improve the cognitive function of SAMP8 mice by regulating CaMKKβ-AMPK-PGC-1α signaling axis to maintain mitochondrial homeostasis and inhibit neuronal apoptosis.

A promising drug repurposing approach for Alzheimer's treatment: Givinostat improves cognitive behavior and pathological features in APP/PS1 mice

Alzheimer's disease (AD) is the most common neurodegenerative disease, characterized by memory loss, speech and motor defects, personality changes, and psychological disorders. The exact cause of AD remains unclear. Current treatments focus on maintaining neurotransmitter levels or targeting β-amyloid (Aβ) protein, but these only alleviate symptoms and do not reverse the disease. Developing new drugs is time-consuming, costly, and has a high failure rate. Utilizing multi-omics for drug repositioning has emerged as a new strategy. Based on transcriptomic perturbation data of over 40,000 drugs in human cells from the LINCS-L1000 database, our study employed the Jaccard index and hypergeometric distribution test for reverse transcriptional feature matching analysis, identifying Givinostat as a potential treatment for AD. Our research found that Givinostat improved cognitive behavior and brain pathology in models and enhanced hippocampal synaptic plasticity. Transcriptome sequencing revealed increased expression of mitochondrial respiratory chain complex proteins in the brains of APP/PS1 mice after Givinostat treatment. Functionally, Givinostat restored mitochondrial membrane potential, reduced reactive oxygen species, and increased ATP content in Aβ-induced HT22 cells. Additionally, it improved mitochondrial morphology and quantity in the hippocampus of APP/PS1 mice and enhanced brain glucose metabolic activity. These effects are linked to Givinostat promoting mitochondrial biogenesis and improving mitochondrial function. In summary, Givinostat offers a promising new strategy for AD treatment by targeting mitochondrial dysfunction.

Glycolytic reprogramming in microglia: A potential therapeutic target for ischemic stroke

Ischemic stroke is currently the second leading cause of mortality worldwide, with limited treatment options available. As resident immune cells, microglia promptly respond to cerebral ischemic injury, influencing neuroinflammatory damage and neurorepair. Studies suggest that microglia undergo metabolic reprogramming from mitochondrial oxidative phosphorylation to glycolysis in response to ischemia, significantly impacting their function during ischemic stroke. Therefore, this study aims to investigate the roles and regulatory mechanisms involved in this process, aiming to identify a new therapeutic target or potential drug candidate.

Exploiting potential molecular compounds for treating testicular seminoma by targeting immune related genes

BACKGROUND

In cases of advanced seminoma, up to 30% of patients may manifest cisplatin resistance, necessitating aggressive salvage therapy, with a consequent 50% risk of mortality attributable to cancer. Nevertheless, beyond chemotherapy and radiotherapy, no further therapeutic modalities have been implemented for these patients.

METHODS

The study commenced with the identification of differentially expressed immune-related genes, which were subsequently subjected to clustering using WGCNA. Prognostic signature construction ensued through the execution of univariable Cox regression, lasso regression, and multivariable Cox regression analyses. To validate the prognostic signature, the TCGA-TGCT and GSE99420 cohorts were employed, with assessments conducted via PFS, C-index, DCA, and ROC analyses. Subsequent exploration of the immune landscape and potential immunotherapeutic applications was undertaken through Cibersort and TIDE analyses. Molecular docking and dynamics simulation techniques were then employed for screening potential molecular compounds. Validation of these findings was pursued through in vitro and vivo assays.

RESULTS

CTLA4, SNX17, and TMX1 were selected to construct the signature. Patients in the high-risk group exhibited diminished progression-free survival rates. The AUC for predicting survival at 1, 3, and 5 years was 0.802, 0.899, and 0.943, respectively, surpassing those of other risk factors, such as lymphovascular invasion and T stage. The C-index for the risk score was 0.838. Decision curve analysis (DCA) suggests that incorporating lymphovascular invasion and the risk score yields the most favorable decision-making outcomes for patients. Moreover, individuals classified as high-risk may derive greater benefit from immunotherapy. Molecular compounds including Rutin, ICG-001, and Doxorubicin can selectively target CTLA4, SNX17, and TMX1, respectively, thereby inhibiting the proliferation and invasive capabilities of seminoma tumor cells in vitro and vivo.

CONCLUSION

The signature initially constructed based on immune-related genes shows promise for predicting outcomes and assessing the efficacy of immunotherapy in seminoma patients. Rutin, ICG-001, and Doxorubicin have demonstrated potential to target these signature genes and inhibit tumor cell viability.

Disrupting stroke-induced GAT-1-syntaxin1A interaction promotes functional recovery after stroke

Although stroke is a frequent cause of permanent disability, our ability to promote stroke recovery is limited. Here, we design a small-molecule stroke recovery promoting agent that works by dissociating γ-aminobutyric acid (GABA) transporter 1 (GAT-1) from syntaxin1A (Synt1A), a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein. Stroke induces an increase in GAT-1-Synt1A interaction in the subacute phase, a critical period for functional recovery. Uncoupling GAT-1-Synt1A reverses stroke-induced GAT-1 dysfunction and cortical excitability decline and enhances synaptic GABAergic inhibition and consequently cortical oscillations and network plasticity by facilitating the assembly of the SNARE complex at the synapse. Based on the molecular mechanism of GAT-1 binding to Synt1A, we design GAT-1-Synt1A blockers. Among them, ZLQ-3 exhibits the greatest potency. Intranasal use of ZLQ-3-1, a glycosylation product of ZLQ-3, substantially lessens impairments of sensorimotor and cognitive functions in rodent models. This compound, or its analogs, may serve as a promoting agent for stroke recovery.

Ultrasound Stimulation Modulates Microglia M1/M2 Polarization and Affects Hippocampal Proteomic Changes in a Mouse Model of Alzheimer's Disease

BACKGROUND

The effectiveness of ultrasound stimulation in treating Alzheimer's disease (AD) has been reported in previous studies, but the underlying mechanisms remain unclear. This study investigated the effects of ultrasound stimulation on the proportion and function of microglia of different phenotypes, as well as on the levels of inflammatory factors. Additionally, it revealed the alterations in proteomic molecules in the mouse hippocampus following ultrasound stimulation treatment, aiming to uncover potential new molecular mechanisms.

METHODS

Ultrasound stimulation was used to stimulate the hippocampus for 30 min per day for 5 days in the ultrasound stimulation-treated group. Amyloid plaque deposition was measured using immunofluorescence staining. M1 and M2 type microglia were labeled using immunofluorescent double staining, and the ratio was calculated. The levels of Aβ42, IL-10, and TNF-α were determined using ELISA kits. The quantitative proteomics method was employed to explore molecular changes in hippocampal proteins.

RESULTS

Ultrasound stimulation treatment reduced the average fluorescence intensity of amyloid plaques and the concentration of Aβ42. Compared to the AD group, ultrasound stimulation resulted in a 14% reduction in the proportion of M1 microglia and a 12% increase in the proportion of M2 microglia. The concentration of the anti-inflammatory factor IL-10 was significantly increased in the ultrasound stimulation-treated group. Proteomics analysis revealed 753 differentially expressed proteins between the ultrasound stimulation-treated and AD groups, with most being enriched in the oxidative phosphorylation pathway of mitochondria. Additionally, the activity of cytochrome c oxidase, involved in oxidative phosphorylation, was increased after ultrasound stimulation treatment.

CONCLUSIONS

Ultrasound stimulation affects microglial polarization, reduces amyloid plaque load, and enhances levels of anti-inflammatory factors in APP/PS1 mice. Proteomics analysis reveals molecular changes in hippocampal proteins after ultrasound stimulation treatment. The mechanism behind ultrasound stimulation-induced modulation of microglial polarization may be related to changes in mitochondrial oxidative phosphorylation.

Widely metabolomic combined with transcriptome analysis to build a bioactive compound regulatory network for the fruit growth cycle in Pseudocydonia sinensis

Neglected and underutilised plants such as Pseudocydonia sinensis (Chinese quince) have garnered global interest as invaluable sources of natural bioactive compounds. Herein, a wide-targeted metabolomics-based approach revealed 1199 concurrent metabolites, with further analysis of their fluctuations across with the five stages of fruit growth. The bioactive compounds in Chinese quince primarily comprised sugars and organic acids, flavonoids, and terpenoids. Moreover, 395 metabolites were identified as having medicinal properties and rutin was the most content of them. Transcriptome analysis further provided a molecular basis for the metabolic changes observed during fruit development. By thoroughly analysing metabolite and transcriptome data, we revealed changes in bioactive compounds and related genes throughout fruit development. This study has yielded valuable insights into the ripening process of Chinese quince fruit, presenting substantial implications for industrial applications, particularly in quality control.

Complement 3a induces the synapse loss via C3aR in mitochondria-dependent NLRP3 activating mechanisms during the development and progression of Alzheimer's disease

As a central molecule in complement system (CS), complement (C) 3 is upregulated in the patients and animal models of Alzheimer's disease (AD). C3 will metabolize to iC3b and C3a. iC3b is responsible for clearing β-amyloid protein (Aβ). In this scenario, C3 exerts neuroprotective effects against the disease via iC3b. However, C3a will inhibit microglia to clear the Aβ, leading to the deposition of Aβ and impair the functions of synapses. To their effects on AD, activation of C3a and C3a receptor (C3aR) will impair the mitochondria, leading to the release of reactive oxygen species (ROS), which activates the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasomes. The overloading of NLRP3 inflammasomes activate microglia, leading to the formation of inflammatory environment. The inflammatory environment will facilitate the deposition of Aβ and abnormal synapse pruning, which results in the progression of AD. Therefore, the current review will decipher the mechanisms of C3a inducing the synapse loss via C3aR in mitochondria-dependent NLRP3 activating mechanisms, which facilitates the understanding the AD.

Rutin Ameliorates ALS Pathology by Reducing SOD1 Aggregation and Neuroinflammation in an SOD1-G93A Mouse Model

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive loss of motor neurons, with limited effective treatments. Recently, the exploration of natural products has unveiled their potential in exerting neuroprotective effects, offering a promising avenue for ALS therapy. In this study, the therapeutic effects of rutin, a natural flavonoid glycoside with neuroprotective properties, were evaluated in a superoxide dismutase 1 (SOD1)-G93A mouse model of ALS. We showed that rutin reduced the level of SOD1 aggregation and diminished glial cell activation in spinal cords and brainstems, resulting in significantly improved motor function and motor neuron restoration in SOD1-G93A mice. Our findings indicated that rutin's multi-targeted approach to SOD1-related pathology makes it a promising candidate for the treatment of ALS.

Flavonoids as therapeutic agents for epilepsy: unveiling anti-inflammatory and antioxidant pathways for novel treatments

Epilepsy, a chronic neurological disorder affecting millions globally, is often exacerbated by neuroinflammation and oxidative stress. Existing antiepileptic drugs primarily manage symptoms, leaving the disease's progression largely unaddressed. Flavonoids, ubiquitous plant metabolites with potent anti-inflammatory and antioxidant properties, show promise in epilepsy treatment. Unlike conventional therapies, they target multiple pathophysiological processes simultaneously, offering a comprehensive approach to this complex neurological disorder. This review explores the dual role of flavonoids in mitigating neuroinflammation and reducing oxidative stress through various molecular pathways. By inhibiting key inflammatory mediators and pathways such as NF-κB, MAPK, JNK, and JAK, flavonoids offer neuronal protection. They enhance the body's natural antioxidant defenses by modulating enzyme activities, including superoxide dismutase, catalase, and glutathione peroxidase. Moreover, flavonoids influence crucial antioxidant response pathways like PI3K/AKT, Nrf2, JNK, and PKA. Despite their therapeutic promise, the low bioavailability of flavonoids poses a considerable challenge. However, cutting-edge strategies, including nanotechnology and chemical modifications, are underway to improve their bioavailability and therapeutic efficacy. These advancements support the potential of flavonoids as a valuable addition to epilepsy treatment strategies.

Rutin alleviates Pb-induced oxidative stress, inflammation and cell death via activating Nrf2/ARE system in SH-SY5Y cells

Lead (Pb) is harmful to almost all organs, particularly the developmental neural system, and previous studies revealed oxidative stress played an important role in Pb neurotoxicity. Rutin, a type of flavonoid glycoside found in various plants and fruits, is widely used as a dietary supplement due to its antioxidant and anti-inflammatory properties, but whether rutin could protect against Pb neurotoxicity is unclear. In this study, we found rutin treatment significantly alleviated Pb-induced cell death, oxidative stress, and inflammation, resulting in cell survival. Moreover, rutin treatment promoted nuclear factor erythroid 2-related factor 2 (Nrf2) translocation from cytoplasm to nucleus and subsequently activated antioxidant and detoxifying enzymes expression including HO-1. Knocking down Nrf2 by siRNA transfection abolished this protection of rutin against Pb. Overall, rutin could alleviate Pb-induced oxidative stress, inflammation, and cell death by activating the Nrf2/antioxidant response elements (ARE) system.

Taming neuroinflammation in Alzheimer's disease: The protective role of phytochemicals through the gut-brain axis

Alzheimer's disease (AD) is a progressive degenerative neurological condition characterized by cognitive decline, primarily affecting memory and logical thinking, attributed to amyloid-β plaques and tau protein tangles in the brain, leading to neuronal loss and brain atrophy. Neuroinflammation, a hallmark of AD, involves the activation of microglia and astrocytes in response to pathological changes, potentially exacerbating neuronal damage. The gut-brain axis is a bidirectional communication pathway between the gastrointestinal and central nervous systems, crucial for maintaining brain health. Phytochemicals, natural compounds found in plants with antioxidant and anti-inflammatory properties, such as flavonoids, curcumin, resveratrol, and quercetin, have emerged as potential modulators of this axis, suggesting implications for AD prevention. Intake of phytochemicals influences the gut microbial composition and its metabolites, thereby impacting neuroinflammation and oxidative stress in the brain. Consumption of phytochemical-rich foods may promote a healthy gut microbiota, fostering the production of anti-inflammatory and neuroprotective substances. Early dietary incorporation of phytochemicals offers a non-invasive strategy for modulating the gut-brain axis and potentially reducing AD risk or delaying its onset. The exploration of interventions targeting the gut-brain axis through phytochemical intake represents a promising avenue for the development of preventive or therapeutic strategies against AD initiation and progression.

Tetramerization of PKM2 Alleviates Traumatic Brain Injury by Ameliorating Mitochondrial Damage in Microglia

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Microglial activation and neuroinflammation are key cellular events that determine the outcome of TBI, especially neuronal and cognitive function. Studies have suggested that the metabolic characteristics of microglia dictate their inflammatory response. The pyruvate kinase isoform M2 (PKM2), a key glycolytic enzyme, is involved in the regulation of various cellular metabolic processes, including mitochondrial metabolism. This suggests that PKM2 may also participate in the regulation of microglial activation during TBI. Therefore, the present study aimed to evaluate the role of PKM2 in regulating microglial activation and neuroinflammation and its effects on cognitive function following TBI. A controlled cortical impact (CCI) mouse model and inflammation-induced primary mouse microglial cells in vitro were used to investigate the potential effects of PKM2 inhibition and regulation. PKM2 was significantly increased during the acute and subacute phases of TBI and was predominantly detected in microglia rather than in neurons. Our results demonstrate that shikonin and TEPP-46 can inhibit microglial inflammation, improving mitochondria, improving mouse behavior, reducing brain defect volume, and alleviating pathological changes after TBI. There is a difference in the intervention of shikonin and TEPP-46 on PKM2. Shikonin directly inhibits General PKM2; TEPP-46 can promote the expression of PKM2 tetramer. In vitro experiments, TEPP-46 can promote the expression of PKM2 tetramer, enhance the interaction between PKM2 and MFN2, improve mitochondria, alleviate neuroinflammation. General inhibition and tetramerization activation of PKM2 attenuated cognitive function caused by TBI, whereas PKM2 tetramerization exhibited a better treatment effect. Our experiments demonstrated the non-metabolic role of PKM2 in the regulation of microglial activation following TBI. Both shikonin and TEPP-46 can inhibit pro-inflammatory factors, but only TEPP-46 can promote PKM2 tetramerization and upregulate the release of anti-inflammatory factors from microglia.

Brain resident microglia in Alzheimer's disease: foe or friends

The neurobiology of Alzheimer's disease (AD) is unclear due to its multifactorial nature. Although a wide range of studies revealed several pathomechanisms of AD, dementia is yet unmanageable with current pharmacotherapies. The recent growing literature illustrates the role of microglia-mediated neuroinflammation in the pathogenesis of AD. Indeed, microglia serve as predominant sentinels of the brain, which diligently monitor the neuroimmune axis by phagocytosis and releasing soluble factors. In the case of AD, microglial cells are involved in synaptic pruning and remodeling by producing inflammatory mediators. The conditional inter-transformation of classical activation (proinflammatory) or alternative activation (anti-inflammatory) microglia is responsible for most brain disorders. In this review, we discussed the role of microglia in neuroinflammatory processes in AD following the accumulation of amyloid-β and tau proteins. We also described the prominent phenotypes of microglia, such as disease-associated microglia (DAM), dark microglia, interferon-responsive microglia (IRMs), human AD microglia (HAMs), and microglial neurodegenerative phenotype (MGnD), which are closely associated with AD incidence. Considering the key role of microglia in AD progression, microglial-based therapeutics may hold promise in mitigating cognitive deficits by addressing the neuroinflammatory responses.

Efficient Light-Based Bioprinting via Rutin Nanoparticle Photoinhibitor for Advanced Biomedical Applications

Digital light processing (DLP) bioprinting, known for its high resolution and speed, enables the precise spatial arrangement of biomaterials and has become integral to advancing tissue engineering and regenerative medicine. Nevertheless, inherent light scattering presents significant challenges to the fidelity of the manufactured structures. Herein, we introduce a photoinhibition strategy based on Rutin nanoparticles (Rnps), attenuating the scattering effect through concurrent photoabsorption and free radical reaction. Compared to the widely utilized biocompatible photoabsorber tartrazine (Tar), Rnps-infused bioink enhanced printing speed (1.9×), interlayer homogeneity (58% less overexposure), resolution (38.3% improvement), and print tolerance (3× high-precision range) to minimize trial-and-error. The biocompatible and antioxidative Rnps significantly improved cytocompatibility and exhibited resistance to oxidative stress-induced damage in printed constructs, as demonstrated with human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs). The related properties of Rnps facilitate the facile fabrication of multimaterial, heterogeneous, and cell-laden biomimetic constructs with intricate structures. The developed photoinhibitor, with its profound adaptability, promises wide biomedical applications tailored to specific biological requirements.

Excitotoxicity, Oxytosis/Ferroptosis, and Neurodegeneration: Emerging Insights into Mitochondrial Mechanisms

Mitochondrial dysfunction plays a pivotal role in the development of age-related diseases, particularly neurodegenerative disorders. The etiology of mitochondrial dysfunction involves a multitude of factors that remain elusive. This review centers on elucidating the role(s) of excitotoxicity, oxytosis/ferroptosis and neurodegeneration within the context of mitochondrial bioenergetics, biogenesis, mitophagy and oxidative stress and explores their intricate interplay in the pathogenesis of neurodegenerative diseases. The effective coordination of mitochondrial turnover processes, notably mitophagy and biogenesis, is assumed to be critically important for cellular resilience and longevity. However, the age-associated decrease in mitophagy impedes the elimination of dysfunctional mitochondria, consequently impairing mitochondrial biogenesis. This deleterious cascade results in the accumulation of damaged mitochondria and deterioration of cellular functions. Both excitotoxicity and oxytosis/ferroptosis have been demonstrated to contribute significantly to the pathophysiology of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's Disease (HD), Amyotrophic Lateral Sclerosis (ALS) and Multiple Sclerosis (MS). Excitotoxicity, characterized by excessive glutamate signaling, initiates a cascade of events involving calcium dysregulation, energy depletion, and oxidative stress and is intricately linked to mitochondrial dysfunction. Furthermore, emerging concepts surrounding oxytosis/ferroptosis underscore the importance of iron-dependent lipid peroxidation and mitochondrial engagement in the pathogenesis of neurodegeneration. This review not only discusses the individual contributions of excitotoxicity and ferroptosis but also emphasizes their convergence with mitochondrial dysfunction, a key driver of neurodegenerative diseases. Understanding the intricate crosstalk between excitotoxicity, oxytosis/ferroptosis, and mitochondrial dysfunction holds potential to pave the way for mitochondrion-targeted therapeutic strategies. Such strategies, with a focus on bioenergetics, biogenesis, mitophagy, and oxidative stress, emerge as promising avenues for therapeutic intervention.

Cordycepin Modulates Microglial M2 Polarization Coupled with Mitochondrial Metabolic Reprogramming by Targeting HKII and PDK2

The microenvironment mediated by the microglia (MG) M1/M2 phenotypic switch plays a decisive role in the neuronal fate and cognitive function of Alzheimer's disease (AD). However, the impact of metabolic reprogramming on microglial polarization and its underlying mechanism remains elusive. This study reveals that cordycepin improved cognitive function and memory in APP/PS1 mice, as well as attenuated neuronal damage by triggering MG-M2 polarization and metabolic reprogramming characterized by increased OXPHOS and glycolysis, rather than directly protecting neurons. Simultaneously, cordycepin partially alleviates mitochondrial damage in microglia induced by inhibitors of OXPHOS and glycolysis, further promoting MG-M2 transformation and increasing neuronal survival. Through confirmation of cordycepin distribution in the microglial mitochondria via mitochondrial isolation followed by HPLC-MS/MS techniques, HKII and PDK2 are further identified as potential targets of cordycepin. By investigating the effects of HKII and PDK2 inhibitors, the mechanism through which cordycepin targeted HKII to elevate ECAR levels in the glycolysis pathway while targeting PDK2 to enhance OCR levels in PDH-mediated OXPHOS pathway, thereby inducing MG-M2 polarization, promoting neuronal survival and exerting an anti-AD role is elucidated.

Extracellular Matrix Remodeling Alleviates Memory Deficits in Alzheimer's Disease by Enhancing the Astrocytic Autophagy-Lysosome Pathway

Extracellular matrix (ECM) remodeling is strongly linked to Alzheimer's disease (AD) risk; however, the underlying mechanisms are not fully understood. Here, it is found that the injection of chondroitinase ABC (ChABC), mimicking ECM remodeling, into the medial prefrontal cortex (mPFC) reversed short-term memory loss and reduced amyloid-beta (Aβ) deposition in 5xFAD mice. ECM remodeling also reactivated astrocytes, reduced the levels of aggrecan in Aβ plaques, and enhanced astrocyte recruitment to surrounding plaques. Importantly, ECM remodeling enhanced the autophagy-lysosome pathway in astrocytes, thereby mediating Aβ clearance and alleviating AD pathology. ECM remodeling also promoted Aβ plaque phagocytosis by astrocytes by activating the astrocytic phagocytosis receptor MERTK and promoting astrocytic vesicle circulation. The study identified a cellular mechanism in which ECM remodeling activates the astrocytic autophagy-lysosomal pathway and alleviates AD pathology. Targeting ECM remodeling may represent a potential therapeutic strategy for AD and serve as a reference for the treatment of this disease.

Therapeutic targeting of immunometabolism reveals a critical reliance on hexokinase 2 dosage for microglial activation and Alzheimer's progression

Neuroinflammation is a prominent feature of Alzheimer's disease (AD). Activated microglia undergo a reprogramming of cellular metabolism necessary to power their cellular activities during disease. Thus, selective targeting of microglial immunometabolism might be of therapeutic benefit for treating AD. In the AD brain, the levels of microglial hexokinase 2 (HK2), an enzyme that supports inflammatory responses by promoting glycolysis, are significantly increased. In addition, HK2 displays non-metabolic activities that extend its inflammatory role beyond glycolysis. The antagonism of HK2 affects microglial phenotypes and disease progression in a gene-dose-dependent manner. HK2 complete loss fails to improve pathology by exacerbating inflammation, while its haploinsufficiency reduces pathology in 5xFAD mice. We propose that the partial antagonism of HK2 is effective in slowing disease progression by modulating NF-κB signaling through its cytosolic target, IKBα. The complete loss of HK2 affects additional inflammatory mechanisms related to mitochondrial dysfunction.

sAPPα Peptide Promotes Damaged Microglia to Clear Alzheimer's Amyloid-β via Restoring Mitochondrial Function

Alzheimer's disease (AD) is an age-related neurodegenerative disease with amyloid-β (Aβ) deposition as the main pathological feature. It's an important challenge to find new ways to clear Aβ from the brain. The soluble amyloid precursor protein α (sAPPα) is a neuroprotective protein and can attenuate neuronal damage, including toxic Aβ. However, the regulatory role of sAPPα in non-neuronal cells, such as microglia, is less reported and controversial. Here, we showed that sAPPα promoted the phagocytosis and degradation of Aβ in both normal and damaged microglia. Moreover, the function of damaged microglia was improved by the sAPPα through normalizing mitochondrial function. Furthermore, the results of molecular docking simulation showed that sAPPα had a good affinity with Aβ. We preliminarily reveal that sAPPα is similar to antibodies and can participate in the regulation of microglia phagocytosis and degradation of Aβ after binding to Aβ. sAPPα is expected to be a mild and safe peptide drug or drug carrier for AD.

Simultaneous estimation of rutin and donepezil through RP-HPLC: implication in pharmaceutical and biological samples

Aim: A HPLC method was developed and validated for the novel combination of rutin (RN) and donepezil (DNP). Materials & methods: RN and DNP were simultaneously eluted through a C18 column (Ø 150 × 4.6 mm) with a 60:40 v/v ratio of 0.1% formic acid aqueous solution to methanol at 0.5 ml/min. Results: The purposed method was found linear, selective, reproducible, accurate and precise with percent RSD less than 2. The limit of quantification for RN and DNP was found 3.66 and 3.25 μg/ml, respectively. Conclusion: Validated as per the ICH guidelines, the developed method efficiently quantified RN and DNP co-loaded in DQAsomes (121 nm) estimating matrix effect, release profile, entrapment efficiency, loading efficiency and in vivo plasma kinetics.

Monocytes release cystatin F dimer to associate with Aβ and aggravate amyloid pathology and cognitive deficits in Alzheimer's disease

BACKGROUND

Understanding the molecular mechanisms of Alzheimer's disease (AD) has important clinical implications for guiding therapy. Impaired amyloid beta (Aβ) clearance is critical in the pathogenesis of sporadic AD, and blood monocytes play an important role in Aβ clearance in the periphery. However, the mechanism underlying the defective phagocytosis of Aβ by monocytes in AD remains unclear.

METHODS

Initially, we collected whole blood samples from sporadic AD patients and isolated the monocytes for RNA sequencing analysis. By establishing APP/PS1 transgenic model mice with monocyte-specific cystatin F overexpression, we assessed the influence of monocyte-derived cystatin F on AD development. We further used a nondenaturing gel to identify the structure of the secreted cystatin F in plasma. Flow cytometry, enzyme-linked immunosorbent assays and laser scanning confocal microscopy were used to analyse the internalization of Aβ by monocytes. Pull down assays, bimolecular fluorescence complementation assays and total internal reflection fluorescence microscopy were used to determine the interactions and potential interactional amino acids between the cystatin F protein and Aβ. Finally, the cystatin F protein was purified and injected via the tail vein into 5XFAD mice to assess AD pathology.

RESULTS

Our results demonstrated that the expression of the cystatin F protein was specifically increased in the monocytes of AD patients. Monocyte-derived cystatin F increased Aβ deposition and exacerbated cognitive deficits in APP/PS1 mice. Furthermore, secreted cystatin F in the plasma of AD patients has a dimeric structure that is closely related to clinical signs of AD. Moreover, we noted that the cystatin F dimer blocks the phagocytosis of Aβ by monocytes. Mechanistically, the cystatin F dimer physically interacts with Aβ to inhibit its recognition and internalization by monocytes through certain amino acid interactions between the cystatin F dimer and Aβ. We found that high levels of the cystatin F dimer protein in blood contributed to amyloid pathology and cognitive deficits as a risk factor in 5XFAD mice.

CONCLUSIONS

Our findings highlight that the cystatin F dimer plays a crucial role in regulating Aβ metabolism via its peripheral clearance pathway, providing us with a potential biomarker for diagnosis and potential target for therapeutic intervention.

Glycometabolic Reprogramming of Microglia in Neurodegenerative Diseases: Insights from Neuroinflammation

Neurodegenerative diseases (ND) are conditions defined by progressive deterioration of the structure and function of the nervous system. Some major examples include Alzheimer's disease (AD), Parkinson's disease (PD), and Amyotrophic lateral sclerosis (ALS). These diseases lead to various dysfunctions, like impaired cognition, memory, and movement. Chronic neuroinflammation may underlie numerous neurodegenerative disorders. Microglia, an important immunocell in the brain, plays a vital role in defending against neuroinflammation. When exposed to different stimuli, microglia are activated and assume different phenotypes, participating in immune regulation of the nervous system and maintaining tissue homeostasis. The immunological activity of activated microglia is affected by glucose metabolic alterations. However, in the context of chronic neuroinflammation, specific alterations of microglial glucose metabolism and their mechanisms of action remain unclear. Thus, in this paper, we review the glycometabolic reprogramming of microglia in ND. The key molecular targets and main metabolic pathways are the focus of this research. Additionally, this study explores the mechanisms underlying microglial glucose metabolism reprogramming in ND and offers an analysis of the most recent therapeutic advancements. The ultimate aim is to provide insights into the development of potential treatments for ND.

RUTIN, a widely consumed flavonoid, that commonly induces hormetic effects

Rutin is a flavonoid present in numerous fruits and vegetables and therefore widely consumed by humans. It is also a popular dietary supplement of 250-500 mg/day. There is considerable consumer interest in rutin due to numerous reports in the biomedical literature of its multi-system chemo-preventive properties. The present paper provides the first assessment of rutin-induced hormetic concentration/dose responses, their quantitative features and mechanistic basis, along with their biological, biomedical, clinical, and public health implications. The findings indicate that rutin-induced hormetic dose responses are widespread, being reported in numerous biological models and cell types for a wide range of endpoints. Of critical importance is that the optimal hormetic findings shown in in vitro systems are currently not achievable for human populations due to low gastrointestinal tract bioavailability. These findings have the potential to strengthen future experimental studies with rutin, particularly concerning study design parameters.

Mitochondrial dysfunction in chronic neuroinflammatory diseases (Review)

Chronic neuroinflammation serves a key role in the onset and progression of neurodegenerative disorders. Mitochondria serve as central regulators of neuroinflammation. In addition to providing energy to cells, mitochondria also participate in the immunoinflammatory response of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, multiple sclerosis and epilepsy, by regulating processes such as cell death and inflammasome activation. Under inflammatory conditions, mitochondrial oxidative stress, epigenetics, mitochondrial dynamics and calcium homeostasis imbalance may serve as underlying regulatory mechanisms for these diseases. Therefore, investigating mechanisms related to mitochondrial dysfunction may result in therapeutic strategies against chronic neuroinflammation and neurodegeneration. The present review summarizes the mechanisms of mitochondria in chronic neuroinflammatory diseases and the current treatment approaches that target mitochondrial dysfunction in these diseases.

Potential Alzheimer's disease drug targets identified through microglial biology research

INTRODUCTION

Microglia, the primary immune cells in the brain, play multifaceted roles in Alzheimer's disease (AD). Microglia can potentially mitigate the pathological progression of AD by clearing amyloid beta (Aβ) deposits in the brain and through neurotrophic support. In contrast, disproportionate activation of microglial pro-inflammatory pathways, as well as excessive elimination of healthy synapses, can exacerbate neurodegeneration in AD. The challenge, therefore, lies in discerning the precise regulation of the contrasting microglial properties to harness their therapeutic potential in AD.

AREAS COVERED

This review examines the evidence relevant to the disease-modifying effects of microglial manipulators in AD preclinical models. The deleterious pro-inflammatory effects of microglia in AD can be ameliorated via direct suppression or indirectly through metabolic manipulation, epigenetic targeting, and modulation of the gut-brain axis. Furthermore, microglial clearance of Aβ deposits in AD can be enhanced via strategically targeting microglial membrane receptors, lysosomal functions, and metabolism.

EXPERT OPINION

Given the intricate and diverse nature of microglial responses throughout the course of AD, therapeutic interventions directed at microglia warrant a tactical approach. This could entail employing therapeutic regimens, which concomitantly suppress pro-inflammatory microglial responses while selectively enhancing Aβ phagocytosis.

Effect of Cerebralcare Granule® combined with memantine on Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

In elderly people, Alzheimer's disease (AD) is the most common form of dementia. It has been shown that traditional Chinese medicine (TCM) based on phytomedicines enhances the therapeutic effects of modern medicine when taken in conjunction with them. Modern medicine N-methyl-D-aspartate receptor (NMDA) antagonist memantine (Mm) are mainly used in the clinical treatment of AD. TCM Cerebralcare Granule® (CG) has long been an effective treatment for headaches, dizziness, and other symptoms. In this study, we employ a blend of CG and Mm to address Alzheimer's disease-like symptoms and explore their impacts and underlying mechanisms.

AIM OF THE STUDY

The objective of our study was to observe the effects of CG combined with Memantine (Mm) on learning and memory impairment of AD mice induced by D-galactose and to explore the mechanism at work.

MATERIALS AND METHODS

CG and Mm were combined to target multiple pathological processes involved in AD. For a thorough analysis, we performed various experiments such as behavioral detection, pathological detection, proteomic detection, and other experimental methods of detection.

RESULTS

It was found that the combination of CG and Mm was significantly effective for improving learning and memory in AD mice as well as brain pathology. The serum and hippocampal tissue of AD mice were significantly enhanced with catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities and malondialdehyde (MDA) levels were decreased with this treatment. In AD mice, a combination of Mm and CG (CG + Mm) significantly increased the levels of the anti-inflammatory factors IL-4 and IL-10, decreased the levels of pro-inflammatory factors (IL-6, IL-1β) and tumor necrosis factor-alpha (TNF-α), improved synaptic plasticity by restoring synaptophysin (SYP) and postsynaptic density protein-95 (PSD-95) expression in the hippocampus, enhanced Aβ phagocytosis of microglia in AD mice, and increased mitochondrial respiratory chain enzyme complexes I, II, III, and IV, lead to an increase in the number of functionally active NMDA receptors in the hippocampus. Proteomic analysis GO analysis showed that the positive regulation gene H3BIV5 of G protein coupled receptor signal pathway and synaptic transmission was up-regulated, while the transsynaptic signal of postsynaptic membrane potential and regulation-related gene Q5NCT9 were down-regulated. Most proteins showed significant enriched signal transduction pathway profiles after CG + Mm treatment, based on the KEGG pathway database.

CONCLUSION

The data supported the idea that CG and Mm could be more effective in treating AD mice induced by D-galactose than Mm alone. We provided a basis for the clinical use of CG with Mm.

Rutin ameliorated lipid metabolism dysfunction of diabetic NAFLD via AMPK/SREBP1 pathway

BACKGROUND

In diabetic liver injury, nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease. Rutin is a bioflavonoid produced by the hydrolysis of glucosidases to quercetin. Its biological activities include lowering blood glucose, regulating insulin secretion, regulating dyslipidemia, and exerting anti-inflammatory effects have been demonstrated. However, its effect on diabetic NAFLD is rarely reported.

PURPOSE

Our study aimed to investigate the protective effects of Rutin on diabetic NAFLD and potential pharmacological mechanism.

METHODS

We used db/db mice as the animal model to investigate diabetic NAFLD. Oleic acid-treated (OA) HeLa cells were examined whether Rutin had the ability to ameliorate lipid accumulation. HepG2 cells treated with 30 mM/l d-glucose and palmitic acid (PA) were used as diabetic NAFLD in vitro models. Total cholesterol (TC) and Triglycerides (TG) levels were determined. Oil red O staining and BODIPY 493/503 were used to detect lipid deposition within cells. The indicators of inflammation and oxidative stress were detected. The mechanism of Rutin in diabetic liver injury with NAFLD was analyzed using RNA-sequence and 16S rRNA, and the expression of fat-synthesizing proteins in the 5' adenosine monophosphate-activated protein kinase (AMPK) pathway was investigated. Compound C inhibitors were used to further verify the relationship between AMPK and Rutin in diabetic NAFLD.

RESULTS

Rutin ameliorated lipid accumulation in OA-treated HeLa. In in vitro and in vivo models of diabetic NAFLD, Rutin alleviated lipid accumulation, inflammation, and oxidative stress. 16S analysis showed that Rutin could reduce gut microbiota dysregulation, such as the ratio of Firmicutes to Bacteroidetes. RNA-seq showed that the significantly differentially genes were mainly related to liver lipid metabolism. And the ameliorating effect of Rutin on diabetic NAFLD was through AMPK/SREBP1 pathway and the related lipid synthesis proteins was involved in this process.

CONCLUSION

Rutin ameliorated diabetic NAFLD by activating the AMPK pathway and Rutin might be a potential new drug ingredient for diabetic NAFLD.

The Role of Glial Cells in Synaptic Dysfunction: Insights into Alzheimer's Disease Mechanisms

Alzheimer's disease (AD) is a devastating neurodegenerative disorder that impacts a substantial number of individuals globally. Despite its widespread prevalence, there is currently no cure for AD. It is widely acknowledged that normal synaptic function holds a key role in memory, cognitive abilities, and the interneuronal transfer of information. As AD advances, symptoms including synaptic impairment, decreased synaptic density, and cognitive decline become increasingly noticeable. The importance of glial cells in the formation of synapses, the growth of neurons, brain maturation, and safeguarding the microenvironment of the central nervous system is well recognized. However, during AD progression, overactive glial cells can cause synaptic dysfunction, neuronal death, and abnormal neuroinflammation. Both neuroinflammation and synaptic dysfunction are present in the early stages of AD. Therefore, focusing on the changes in glia-synapse communication could provide insights into the mechanisms behind AD. In this review, we aim to provide a summary of the role of various glial cells, including microglia, astrocytes, oligodendrocytes, and oligodendrocyte precursor cells, in regulating synaptic dysfunction. This may offer a new perspective on investigating the underlying mechanisms of AD.

Neuroinflammation of Microglial Regulation in Alzheimer's Disease: Therapeutic Approaches

Alzheimer's disease (AD) is a complex degenerative disease of the central nervous system that is clinically characterized by a progressive decline in memory and cognitive function. The pathogenesis of AD is intricate and not yet fully understood. Neuroinflammation, particularly microglial activation-mediated neuroinflammation, is believed to play a crucial role in increasing the risk, triggering the onset, and hastening the progression of AD. Modulating microglial activation and regulating microglial energy metabolic disorder are seen as promising strategies to intervene in AD. The application of anti-inflammatory drugs and the targeting of microglia for the prevention and treatment of AD has emerged as a new area of research interest. This article provides a comprehensive review of the role of neuroinflammation of microglial regulation in the development of AD, exploring the connection between microglial energy metabolic disorder, neuroinflammation, and AD development. Additionally, the advancements in anti-inflammatory and microglia-regulating therapies for AD are discussed.