Astrocytic and microglial cells as the modulators of neuroinflammation in Alzheimer's disease

Inflammasome links traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease

Traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease are three distinct neurological disorders that share common pathophysiological mechanisms involving neuroinflammation. One sequela of neuroinflammation includes the pathologic hyperphosphorylation of tau protein, an endogenous microtubule-associated protein that protects the integrity of neuronal cytoskeletons. Tau hyperphosphorylation results in protein misfolding and subsequent accumulation of tau tangles forming neurotoxic aggregates. These misfolded proteins are characteristic of traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease and can lead to downstream neuroinflammatory processes, including assembly and activation of the inflammasome complex. Inflammasomes refer to a family of multimeric protein units that, upon activation, release a cascade of signaling molecules resulting in caspase-induced cell death and inflammation mediated by the release of interleukin-1β cytokine. One specific inflammasome, the NOD-like receptor protein 3, has been proposed to be a key regulator of tau phosphorylation where it has been shown that prolonged NOD-like receptor protein 3 activation acts as a causal factor in pathological tau accumulation and spreading. This review begins by describing the epidemiology and pathophysiology of traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease. Next, we highlight neuroinflammation as an overriding theme and discuss the role of the NOD-like receptor protein 3 inflammasome in the formation of tau deposits and how such tauopathic entities spread throughout the brain. We then propose a novel framework linking traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease as inflammasome-dependent pathologies that exist along a temporal continuum. Finally, we discuss potential therapeutic targets that may intercept this pathway and ultimately minimize long-term neurological decline.

New perspectives on galectin in major depressive disorder treatment

Galectins, a family of carbohydrate-binding proteins, regulate immune responses, neuroinflammation, and neurogenesis within the central nervous system (CNS). Among the 15 known galectins, galectins-1, -3, -4, -8, and -9 play significant roles in neuroinflammation and have been investigated in the context of CNS pathologies. This review synthesizes recent advancements in understanding galectins' involvement in the neurobiology of brain disorders, focusing on their interplay with signaling pathways underlying major depressive disorder (MDD). It explores their impact on neuroinflammation, neurogenesis, and brain signaling, highlighting the therapeutic potential of targeting galectins while addressing challenges in translating these findings into clinical practice. Comprehensive studies are essential to unravel the complex mechanisms of galectin-mediated pathways and unlock their full potential for managing neuropsychiatric conditions.

Characterizing oxidative stress induced by Aβ oligomers and the protective role of carnosine in primary mixed glia cultures

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and memory loss. A critical aspect of AD pathology is represented by oxidative stress, which significantly contributes to neuronal damage and death. Microglia and astrocytes, the primary glial cells in the brain, are crucial for managing oxidative stress and supporting neuronal function. Carnosine is an endogenous dipeptide possessing a multimodal mechanism of action that includes antioxidant, anti-inflammatory, and anti-aggregant activities. The present study investigated the effects of Aβ1-42 oligomers (oAβ), small aggregates associated with the neurodegeneration observed in AD, on primary rat mixed glia cultures composed of both microglia and astrocytes, focusing on the ability of these detrimental species to induce oxidative stress. We assessed intracellular reactive oxygen species (ROS) and nitric oxide (NO) levels as markers of oxidative stress. Exposure to oAβ significantly elevated both ROS and NO intracellular levels compared to control cells. However, this effect was completely inhibited by the pre-treatment of mixed cultures with carnosine, resulting in ROS and NO levels similar to those observed in untreated (control) cells. Single-cell analysis of cellular responses to oAβ revealed heterogeneous ROS production, resulting in two distinct clusters of cells, one of which was very responsive to the treatment. The presence of carnosine counteracted the overproduction of ROS, also leading to a single, homogeneous cluster, similar to that observed in the case of control cells. Interestingly, unlike ROS response, single-cell analysis of NO production did not show any distinct clusters. Overall, our findings demonstrated the ability of carnosine to mitigate Aβ-induced oxidative stress in mixed glia cells, by rescuing ROS and NO intracellular levels, as well as to normalize the heterogeneous response to the treatment measured in terms of clusters' formation. The present study suggests a therapeutic potential of carnosine in pathologies characterized by oxidative stress including AD.

LCN2 induces neuronal loss and facilitates sepsis-associated cognitive impairments

Sepsis-associated encephalopathy (SAE) is a severe neurological syndrome marked by widespread brain dysfunctions due to sepsis. Despite increasing data supporting the hypothesis of neuronal damage, the exact mechanism of sepsis-related cognitive disorders and therapeutic strategies remain unclear and need further investigation. In this study, a sepsis model was established in C57 mice using lipopolysaccharide (LPS). The findings demonstrated that LPS exposure induced neuronal loss, synaptic and cognitive deficits accompanied by mitochondrial damage. Bioinformatics and western blot analyses demonstrated a significant increase in Lipocalin-2 (LCN2) during sepsis as a key hub gene involved in immune and neurological inflammation. Interestingly, the recombinant LCN2 protein exhibited similar effects on synaptic dysfunction and cognitive deficits in C57 mice. Conversely, downregulating LCN2 effectively nullified the impact of LPS, leading to the amelioration of synaptic and cognitive deficits, neuronal loss, and reactive oxygen species (ROS)-associated mitochondrial damage. These findings suggest a novel etiopathogenic mechanism of SAE, which is initiated by the increased LCN2, leading to neuronal loss and cognitive deficit. Inhibition of LCN2 could be therapeutically beneficial in treating sepsis-induced synaptic and cognitive impairments.

Neurodegenerative diseases and neuroinflammation-induced apoptosis

Neuroinflammation represents a critical pathway in the brain for the clearance of foreign bodies and the maintenance of homeostasis. When the neuroinflammatory process is dysregulate, such as the over-activation of microglia, which results in the excessive accumulation of free oxygen and inflammatory factors in the brain, among other factors, it can lead to an imbalance in homeostasis and the development of various diseases. Recent research has indicated that the development of numerous neurodegenerative diseases is closely associated with neuroinflammation. The pathogenesis of neuroinflammation in the brain is intricate, involving alterations in numerous genes and proteins, as well as the activation and inhibition of signaling pathways. Furthermore, excessive inflammation can result in neuronal cell apoptosis, which can further exacerbate the extent of the disease. This article presents a summary of recent studies on the relationship between neuronal apoptosis caused by excessive neuroinflammation and neurodegenerative diseases. The aim is to identify the link between the two and to provide new ideas and targets for exploring the pathogenesis, as well as the prevention and treatment of neurodegenerative diseases.

Dissecting the immune response of CD4+ T cells in Alzheimer's disease

The formation of amyloid-β (Aβ) plaques is a neuropathological hallmark of Alzheimer's disease (AD), however, these pathological aggregates can also be found in the brains of cognitively unimpaired elderly population. In that context, individual variations in the Aβ-specific immune response could be key factors that determine the level of Aβ-induced neuroinflammation and thus the propensity to develop AD. CD4+ T cells are the cornerstone of the immune response that coordinate the effector functions of both adaptive and innate immunity. However, despite intensive research efforts, the precise role of these cells during AD pathogenesis is still not fully elucidated. Both pathogenic and beneficial effects have been observed in various animal models of AD, as well as in humans with AD. Although this functional duality of CD4+ T cells in AD can be simply attributed to the vast phenotype heterogeneity of this cell lineage, disease stage-specific effect have also been proposed. Therefore, in this review, we summarized the current understanding of the role of CD4+ T cells in the pathophysiology of AD, from the aspect of their antigen specificity, activation, and phenotype characteristics. Such knowledge is of practical importance as it paves the way for immunomodulation as a therapeutic option for AD treatment, given that currently available therapies have not yielded satisfactory results.

Methamphetamine and HIV-1 Tat Synergistically Induce Microglial Pyroptosis Via Activation of the AIM2 Inflammasome

OBJECTIVE

Human immunodeficiency virus (HIV)-infected individuals who abuse methamphetamine (METH) exhibit more severe neurotoxicity and cognitive impairment. Pyroptosis, a programmed cell death pathway mediated by the inflammasome, has been implicated in various neurological diseases. This study aimed to elucidate the role of the AIM2 inflammasome in METH- and HIV-1 Tat-induced pyroptosis in human brain tissue and in vitro models.

METHODS

Postmortem brain tissue from HIV-infected individuals with a history of METH abuse was analyzed for pyroptosis markers and AIM2 inflammasome components using immunohistochemistry, immunofluorescence, and Western blotting. BV2 microglial cells were lentivirally transduced to knockdown AIM2 expression. DNA damage was assessed using Western blotting and the comet assay. Expression of pyroptosis-related proteins was evaluated by electron microscopy, Western blotting, and immunofluorescence. Cell viability was measured using the CCK8 assay.

RESULTS

Elevated levels of pyroptosis markers and AIM2 inflammasome components were observed in brain tissue from HIV-infected METH users. METH and Tat synergistically induced pyroptosis in BV2 cells in a time- and concentration-dependent manner, accompanied by DNA damage and activation of the AIM2 inflammasome. Knockdown of AIM2 significantly reduced the expression of pyroptosis-related proteins.

CONCLUSION

METH and HIV-1 Tat proteins synergistically induce microglial pyroptosis by activating the AIM2 inflammasome through dsDNA damage. These findings suggest that targeting the AIM2 inflammasome may be a promising therapeutic strategy for HIV-associated neurocognitive disorder (HAND).

Linking depression and neuroinflammation: crosstalk between glial cells

The inflammatory hypothesis is one of the more widely accepted pathogenesis of depression. Glia plays an important immunomodulatory role in neuroinflammation, mediating interactions between the immune system and the central nervous system (CNS). Glial cell-driven neuroinflammation is not only an important pathological change in depression, but also a potential therapeutic target. This review discusses the association between depression and glial cell-induced neuroinflammation and elucidates the role of glial cell crosstalk in neuroinflammation. Firstly, we focus on the role of glial cells in neuroinflammation in depression and glial cell interactions; secondly, we categorize changes in different glial cells in animal models of depression and depressed patients, focusing on how glial cells mediate inflammatory responses and exacerbate depressive symptoms; Thirdly, we review how conventional and novel antidepressants affect the phenotype and function of glial cells, thereby exerting anti-inflammatory activity; finally, we discuss the role of the gut-brain axis in glial cell function and depression, and objectively analyze the problems that remain in current antidepressant therapy. This review aims to provide an objective analysis of how glial cell cross-talk may mediate neuroinflammation and thereby influence pathologic progression of depression. It is concluded that a novel therapeutic strategy may be to ameliorate glial cell-mediated inflammatory responses.

Korean Red Ginseng Marc-Derived Gintonin Improves Alzheimer's Cognitive Dysfunction by Upregulating LPAR1

Ginseng is a well-established functional food for brain health. However, its active ingredients have not yet been identified. Gintonin is a promising compound isolated from white/red ginseng. Its lysophosphatidic acid (LPA) is an exogenous G protein-coupled LPA receptor (LPAR) agonist. Korean red ginseng marc (KRGM) is a by-product after KRG extractions. In a previous study, we demonstrated that KRGM-derived gintonin (KRGM-G) contains LPA C[Formula: see text], a major functional component of both white and red ginseng. [Formula: see text] transgenic mice and SH-SY5Y cells were used to determine molecular mechanisms involved in KRGM-G-mediated anti-Alzheimer's disease (AD) effects. KRGM-G improved cognition impairment associated with alleviation of amyloid-β accumulation in the brain (hippocampus and cortex) in [Formula: see text] mice. KRGM-G inhibited activation of inflammatory cells (Iba-1-positive microglia and GFAP-positive astrocyte) and expression of pro-inflammatory mediators (IL-1β, IL-6, iNOS, or NO) in the brains of [Formula: see text] mice, increased the viability of H2O2-induced SH-SY5Y cells, and down-regulated the p38 MAPK, NF-κB p65, and STAT3 signaling pathways. KRGM-G also prevented the formation of reactive oxygen species and stimulated the Nrf2-HO-1/4-HNE signaling pathway in the brains of [Formula: see text] mice and SH-SY5Y cells. Interestingly, these positive effects of KRGM-G on AD-related symptoms and immunopathology were associated with up-regulation of LPAR1 in the brains of [Formula: see text] mice. These results suggest that KRGM-G might improve AD-related cognitive dysfunction by stimulating the anti-oxidant pathway (Nrf2) and inhibiting inflammatory pathways (p38/NF-κB/STAT3) through LPAR1.

Cell-cell communications in the brain of hepatic encephalopathy: The neurovascular unit

Many patients with liver diseases are exposed to the risk of hepatic encephalopathy (HE). The incidence of HE in liver patients is high, showing various symptoms ranging from mild symptoms to coma. Liver transplantation is one of the ways to overcome HE. However, not all patients can receive liver transplantation. Moreover, patients who have received liver transplantation have limitations in that they are vulnerable to hepatocellular carcinoma, allograft rejection, and infection. To find other therapeutic strategies, it is important to understand pathological factors and mechanisms that lead to HE after liver disease. Oxidative stress, inflammatory response, hyperammonaemia and metabolic disorders seen after liver diseases have been reported as risk factors of HE. These are known to affect the brain and cause HE. These peripheral pathological factors can impair the blood-brain barrier, cause it to collapse and damage the neurovascular unit component of multiple cells, including vascular endothelial cells, astrocytes, microglia, and neurons, leading to HE. Many previous studies on HE have suggested the impairment of neurovascular unit and cell-cell communication in the pathogenesis of HE. This review focuses on pathological factors that appear in HE, cell type-specific pathological mechanisms, miscommunication/incorrect relationships, and therapeutic candidates between brain cells in HE. This review suggests that regulating communications and interactions between cells may be important in overcoming HE.

Unraveling the Complex Interplay Between Neuroinflammation and Depression: A Comprehensive Review

The relationship between neuroinflammation and depression is a complex area of research that has garnered significant attention in recent years. Neuroinflammation, characterized by the activation of glial cells and the release of pro-inflammatory cytokines, has been implicated in the pathophysiology of depression. The relationship between neuroinflammation and depression is bidirectional; not only can inflammation contribute to the onset of depressive symptoms, but depression itself can also exacerbate inflammatory responses, creating a vicious cycle that complicates treatment and recovery. The present comprehensive review aimed to explore the current findings on the interplay between neuroinflammation and depression, as well as the mechanisms, risk factors, and therapeutic implications. The mechanisms by which neuroinflammation induces depressive-like behaviors are diverse. Neuroinflammation can increase pro-inflammatory cytokines, activate the hypothalamus-pituitary-adrenal (HPA) axis, and impair serotonin synthesis, all of which contribute to depressive symptoms. Furthermore, the activation of microglia has been linked to the release of inflammatory mediators that can disrupt neuronal function and contribute to mood disorders. Stress-induced neuroinflammatory responses can lead to the release of pro-inflammatory cytokines that not only affect brain function but also influence behavior and mood. Understanding these mechanisms is crucial for developing targeted therapies that can mitigate the effects of neuroinflammation on mood disorders.

Brain Glycogen-Its Metabolic Role in Neuronal Health and Neurological Disorders-An Extensive Narrative Review

Background: Brain glycogen is imperative for neuronal health, as it supports energy demands and metabolic processes. This review examines the pathways involved in glycogen storage and utilization in the central nervous system, emphasizing their role in both physiology and pathology. It explores how alterations in glycogen metabolism contribute to neurological disorders, including neurodegenerative diseases, epilepsy, and metabolic conditions while highlighting the bidirectional interaction between neurons and glia in maintaining brain homeostasis. Methods: A comprehensive search of articles published between 2015 and 2025 was conducted using the following databases: ScienceDirect, Scopus, Wiley, Web of Science, Medline, and PubMed. The selection of relevant studies was based on their focus on brain glycogen metabolism and its role in neurological conditions, with studies that did not meet the inclusion criteria being excluded. Results: The metabolic processes of brain glycogen are subject to rigorous regulation by astrocyte-neuron interactions, thereby ensuring metabolic homeostasis and energy availability. The dysregulation of glycogen storage and mobilization has been implicated in the development of synaptic dysfunction, excitotoxicity, and neurodegeneration in a variety of disorders. For instance, aberrant glycogen accumulation in diseases such as Lafora disease has been associated with severe neurodegeneration, while impaired glycogen mobilization has been shown to exacerbate energy deficits in Alzheimer's and epilepsy. Conclusions: Targeting brain glycogen metabolism represents a promising approach for therapeutic intervention in neurological disorders. However, the translation of these strategies to human models remains challenging, particularly with regard to the long-term safety and specificity of glycogen-targeted therapies.

Exploring the Aβ Plaque Microenvironment in Alzheimer's Disease Model Mice by Multimodal Lipid-Protein-Histology Imaging on a Benchtop Mass Spectrometer

Amyloid-β (Aβ) plaque deposits in the brain are a hallmark of Alzheimer's disease (AD) neuropathology. Plaques consist of complex mixtures of peptides like Aβ1-42 and characteristic lipids such as gangliosides, and they are targeted by reactive microglia and astrocytes. Background: In pharmaceutical research and development, it is a formidable challenge to contextualize the different biomolecular classes and cell types of the Aβ plaque microenvironment in a coherent experimental workflow on a single tissue section and on a benchtop imaging reader. Methods: Here, we developed a workflow that combines lipid MALDI mass spectrometry imaging using a vacuum-stable matrix with histopathology stains and with the MALDI HiPLEX immunohistochemistry of plaques and multiple protein markers on a benchtop imaging mass spectrometer. The three data layers consisting of lipids, protein markers, and histology could be co-registered and evaluated together. Results: Multimodal data analysis suggested the extensive co-localization of Aβ plaques with the peptide precursor protein, with a defined subset of lipids and with reactive glia cells on a single brain section in APPPS1 mice. Plaque-associated lipids like ganglioside GM2 and phosphatidylinositol PI38:4 isoforms were readily identified using the tandem MS capabilities of the mass spectrometer. Conclusions: Altogether, our data suggests that complex pathology involving multiple lipids, proteins and cell types can be interrogated by this spatial multiomics workflow on a user-friendly benchtop mass spectrometer.

Influence of immune cells and inflammatory factors on Alzheimer's disease axis: evidence from mediation Mendelian randomization study

BACKGROUND

Alzheimer's disease (AD) is one of the most common forms of dementia in the elderly, characterized by progressive neurodegeneration. While the exact etiology of AD remains unclear, immune inflammation is known to play a significant role in the disease.

METHODS

This study utilized a two-sample Mendelian randomization (MR) approach to assess the causal relationship between different types of immune cells and AD, while considering inflammatory factors as intermediate variables. Data were collected from three sources: immune cell data (731 phenotypes), inflammatory factors (48 cytokines from 8,293 individuals), and AD data (35,274 cases, 59,163 controls). Multiple MR methods were employed to minimize bias, and detailed descriptions of instrumental variable selection and statistical methods were provided.

RESULTS

The study findings suggest potential causal relationships between six different types of immune cells and AD, as well as causal relationships between 13 immune cells and inflammatory factors. Additionally, two statistically significant inflammatory factors were found to have potential causal relationships with AD. Specifically, immune cells CD33-HLA DR + and CD45 on CD33-HLA DR + may further influence AD by regulating Interleukin-2 levels.

CONCLUSION

This study provides valuable insights into the immunoinflammatory pathogenesis of AD and offers partial guidance for the development of relevant interventions, thereby contributing beneficial information for the prevention and treatment of related diseases.

Association of the Lipidome With Alzheimer's Disease and the Mediated Effect of Metabolites: A Two-Step Mendelian Randomization Study

OBJECTIVE

This study aimed to explore the causal effects of lipidome on Alzheimer's disease (AD) and the mediated effects of the metabolites using Mendelian randomization (MR).

METHODS

Data were obtained in genome-wide association studies, and single-nucleotide polymorphisms were screened according to the underlying assumptions of MR. Subsequently, weighted inverse variance was used to analyze the causality of lipidome with AD as well as the mediated effects of metabolites. Finally, MR-Egger, Cochran's Q, and sensitivity analysis were used to assess horizontal pleiotropy, heterogeneity, and robustness of the results, respectively.

RESULTS

The MR analysis showed that phosphatidylcholine (PC) (15:0_18:2) (mediated proportion: 18.30%, p = 0.024) and phosphatidylethanolamine (PE) (18:0_18:2) (mediated proportion: 14.60%, p = 0.028) mediated the reduction of AD risk by lowering betaine levels, which revealed lipidomic susceptibility. The MR-Egger intercept showed no horizontal pleiotropy for all results (p ≥ 0.05). Cochran's Q showed heterogeneity in some of the results. Sensitivity analysis indicated that all results were robust.

CONCLUSION

Our findings reveal the pathways through which PC (15:0_18:2) and PE (18:0_18:2) mediated the reduction of AD risk by lowering betaine levels.

Advances in the Study of Necroptosis in Vascular Dementia: Focus on Blood-Brain Barrier and Neuroinflammation

BACKGROUND

Vascular dementia (VaD) includes a group of brain disorders that are characterized by cerebrovascular pathology.Neuroinflammation, disruption of the blood-brain barrier (BBB) permeability, white matter lesions, and neuronal loss are all significant pathological manifestations of VaD and play a key role in disease progression. Necroptosis, also known asprogrammed necrosis, is a mode of programmed cell death distinct from apoptosis and is closely associated with ischemic injury and neurodegenerative diseases. Recent studies have shown that necroptosis in VaD exacerbates BBB destruction, activates neuroinflammation, promotes neuronal loss, and severely affects VaD prognosis.

RESULTS AND CONCLUSIONS

In this review, we outline the significant roles of necroptosis and its molecular mechanisms in the pathological process of VaD, with a particular focus on the role of necroptosis in modulating neuroinflammation and exacerbating the disruption of BBB permeability in VaD, and elaborate on the molecular regulatory mechanisms and the centrally involved cells of necroptosis mediated by tumor necrosis factor-α in neuroinflammation in VaD. We also analyze the possibility and specific strategy that targeting necroptosis would help inhibit neuroinflammation and BBB destruction in VaD. With a focus on necroptosis, this study delved into its impact on the pathological changes and prognosis of VaD to provide new treatment ideas.

Extract of Tinospora sinensis alleviates LPS-induced neuroinflammation in mice by regulating TLR4/NF-κB/NLRP3 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The dried rattan stem of Tinospora sinensis (Lour.) Merr. is valued for its efficacy of clearing heat and removing toxicity, calming and soothing the nerves. It is widely used in Tibetan medicine for the treatment of rheumatic and aging diseases. Studies have confirmed its anti-inflammatory and ameliorating effects on Alzheimer's disease; however, the anti-neuroinflammation efficacy and mechanism remain unclear.

AIM

This study aimed to explore the anti-neuroinflammation efficacy, major effective ingredients, and potential mechanism of extract of Tinosporae sinenisis (TIS).

METHODS

UPLC-Q-TOF/MS was used to identify the compounds of TIS and the plasma components of rats after gastric administration of TIS. C57BL/6 J mice were continuously intraperitoneally injected with lipopolysaccharide (LPS) (250 μg/kg) for 14 d to establish a neuroinflammation model. The effects of TIS (4.5 g/kg, 9 g/kg) on the learning and memory abilities in mice with neuroinflammation was evaluated using spontaneous activity, novel object recognition, and Morris water maze tests. Pathological changes in the hippocampus were observed using hematoxylin and eosin staining. Gene and protein levels of inflammatory factors in the brain were detected using qRT-PCR and ELISA kits. Iba-1 levels in the brain were detected using immunofluorescence to assess the degree of microglial activation. Network pharmacology, based on the components absorbed into plasma of TIS, was used to predict potential targets and pathways. Proteomics was used to study the differentially expressed proteins and related pathways in the brain tissue of mice with neuroinflammation. Finally, correlation analysis was performed on the results of network pharmacology and proteomics, and proteins related the anti-neuroinflammatory effect of TIS were detected by western blot.

RESULTS

A total of 39 compounds were identified in TIS: genipingentiobioside, isocorydin, reticuline, (-)-argemonine, tinosineside A, tinosinenside A, and costunolide were absorbed into the plasma. After continuous intraperitoneal injection of LPS into C57BL/6 J mice, microglia in the brain tissue were activated and the gene and protein levels of IL-1β, TNF-α, IL-6, and iNOS were increased in the brain tissue, suggesting that the neuroinflammation model was successfully established. TIS reduced Iba-1 levels and gene expression and protein levels of inflammatory factors in the brain of mice with neuroinflammation. Furthermore, TIS improved the pathological changes in the hippocampus and learning and memory abilities caused by neuroinflammation. Network pharmacology has predicted that TNF, IL-1β, and IκBKB are closely related to neuroinflammation. Proteomics identified key differentially expressed proteins, including TNF, NF-κB2, NF-κBIA, and TLR4. Toll-like receptor (TLR), NF-κB, and NOD-like receptor (NLR) signaling pathways are involved in neuroinflammation-related pathways. Correlation analysis revealed TLR, TNF and NLR signaling pathways were closely related to the anti-neuroinflammatory effects of TIS. We observed that TIS alleviated neuroinflammation by inhibiting the TLR4/NF-κB/NLRP3 pathway.

CONCLUSION

Thirty-nine compounds were identified from TIS, among which seven were absorbed into the plasma as prototype components. TIS alleviated LPS-induced neuroinflammation in mice, and its mechanism was related to inhibition of TLR4/NF-κB/NLRP3 signaling pathway.

The ABC transporter A7 modulates neuroinflammation via NLRP3 inflammasome in Alzheimer's disease mice

BACKGROUND

Specific genetic variants in the ATP-binding cassette transporter A7 locus (ABCA7) are associated with an increased risk of Alzheimer's disease (AD). ABCA7 transports lipids from/across cell membranes, regulates Aβ peptide processing and clearance, and modulates microglial and T-cell functions to maintain immune homeostasis in the brain. During AD pathogenesis, neuroinflammation is one of the key mechanisms involved. Therefore, we wanted to investigate the specific role of ABCA7 in microglial activation via the NLRP3 inflammasome.

METHODS

We developed the first humanized, Cre-inducible ABCA7flx knock-in mouse model, crossbred it with the APPPS1-21 β-amyloidosis model, and generated constitutive ABCA7ko and microglia Cx3cr1-specific conditional ABCA7ko AD mice. The role of ABCA7 was analyzed using histological, biochemical, molecular and mass spectrometry methods.

RESULTS

Constitutive knockout of the Abca7 gene in APPPS1 mice increased the levels of Aβ42 and the number of IBA1+ (microglia) and GFAP+ (astrocytes) cells. Changes in the levels of astrocytes and microglia are associated with the activation of the NLRP3 inflammasome and increased levels of proinflammatory cytokines, such as IL1β and TNFα. Interestingly, microglia-specific ABCA7ko restored Aβ42 peptide levels and IBA1+ and GFAP+ and NLRP3-related gene expression to the original APPPS1 mouse levels. In primary glial cell cultures of APPPS1-hA7ko microglia and APPPS1 astrocytes from newborn pups, we observed that conditioned media from LPS-stimulated microglia was able to induce NLRP3 inflammasome expression and proinflammatory cytokine release in astrocytes.

CONCLUSIONS

Our data suggest that ABCA7 transporters regulate the communication between microglia and astrocytes through the NLRP3 inflammasome and the release of proinflammatory cytokines. This regulation implicates ABCA7 as a key driver ultimately involved in the persistence of the inflammatory response observed in AD.

Risk factors and predictive models in the progression from MCI to Alzheimer's disease

BACKGROUND

The conversion of mild cognitive impairment (MCI) to Alzheimer's disease (AD) is related to various factors. The causal relationships among these factors remain unclear. This study aims to investigate pathways of the progression by using causal analysis and build a predictive model with high accuracy.

METHODS

162 MCI patients were recruited from the Alzheimer's Disease Neuroimaging Initiative database. 68 patients progressed to AD. 94 patients did not convert to AD. We captured standard T1-weighted images, processed them for feature extraction, and selected relevant features using mRMR and LASSO to calculate cortical and nuclear scores. The computational causal structure discovery and regression analyses were adopted to analyze the intricate relationships among APOE ε4 alleles, P-tau, Aβ1-42, cortical and nuclear scores. The individualized prediction nomogram was constructed.

RESULTS

Our results indicated that APOE ε4 alleles was the promoter that caused MCI to transform into AD. Three independent pathways were identified, including P-tau, Aβ1-42, and cortical atrophy. P-tau was the cause of nuclear atrophy. The APOE ε4 alleles, P-tau, Aβ1-42, cortical and nuclear scores all had good predictive value for the MCI conversion. The predictive accuracy of the combined model was the highest, with an AUC of 0.918 in the training cohort and 0.908 in the testing cohort. A multi-predictor nomogram was established.

CONCLUSION

Our study elucidated the initiating factors and three independent pathways involved in the conversion of MCI to AD. The predictive value of each factor was clarified and a multi-predictor nomogram was established with high accuracy.

Relationship between enriched environment and neurodegeneration: a review from mechanism to therapy

Enriched environment (EE), as a non-pharmacological intervention, has garnered considerable attention for its potential to ameliorate neurodegenerative diseases (NDs). This review delineated the impact of EE on the biological functions associated with NDs, emphasizing its role in enhancing neural plasticity, reducing inflammation, and bolstering cognitive performance. We discussed the molecular underpinnings of the effects of EE, including modulation of key signaling pathways such as extracellular regulated kinase 1/2 (ERK1/2), mitogen-activated protein kinases (MAPK), and AMPK/SIRT1, which were implicated in neuroprotection and synaptic plasticity. Additionally, we scrutinized the influence of EE on epigenetic modifications and autophagy, processes pivotal to ND pathogenesis. Animal models, encompassing both rodents and larger animals, offer insights into the disease-modifying effects of EE, underscoring its potential as a complementary approach to pharmacological interventions. In summary, EE emerges as a promising strategy to augment cognitive function and decelerate the progression of NDs.

Tau Pathology Drives Disease-Associated Astrocyte Reactivity in Salt-Induced Neurodegeneration

Dietary high salt intake is increasingly recognized as a risk factor for cognitive decline and dementia, including Alzheimer's disease (AD). Recent studies have identified a population of disease-associated astrocytes (DAA)-like astrocytes closely linked to amyloid deposition and tau pathology in an AD mouse model. However, the presence and role of these astrocytes in high-salt diet (HSD) models remain unexplored. In this study, it is demonstrated that HSD significantly induces enhanced reactivity of DAA-like astrocytes in the hippocampal CA3 region of mice, with this reactivity being critically dependent on neuronal tau pathology. Neuronal tau pathology activates adenosine A1R signaling, exacerbating tau pathology by inhibiting the Cers1 pathway, which sustains astrocyte reactivity. Additionally, neurons burdened with tau pathology promote astrocyte reactivity via releasing Proteins Associated with Promoting DAA-like Astrocyte Reactivity (PAPD), with Lcn2 playing a pivotal role. Knockout of Lcn2 or its receptor 24p3R significantly mitigates HSD-induced DAA reactivity and neuroinflammation. These findings suggest a vicious cycle between tau pathology and A1R signaling, driving DAA-like astrocyte reactivity. Targeting the Tau-A1R axis may provide a novel therapeutic strategy for reducing HSD-induced neuroinflammation and cognitive deficits.

Evolution of Alzheimer's Disease Therapeutics: From Conventional Drugs to Medicinal Plants, Immunotherapy, Microbiotherapy and Nanotherapy

Alzheimer's disease (AD) represents an escalating global health crisis, constituting the leading cause of dementia among the elderly and profoundly impairing their quality of life. Current FDA-approved drugs, such as rivastigmine, donepezil, galantamine, and memantine, offer only modest symptomatic relief and are frequently associated with significant adverse effects. Faced with this challenge and in line with advances in the understanding of the pathophysiology of this neurodegenerative condition, various innovative therapeutic strategies have been explored. Here, we review novel approaches inspired by advanced knowledge of the underlying pathophysiological mechanisms of the disease. Among the therapeutic alternatives, immunotherapy stands out, employing monoclonal antibodies to specifically target and eliminate toxic proteins implicated in AD. Additionally, the use of medicinal plants is examined, as their synergistic effects among components may confer neuroprotective properties. The modulation of the gut microbiota is also addressed as a peripheral strategy that could influence neuroinflammatory and degenerative processes in the brain. Furthermore, the therapeutic potential of emerging approaches, such as the use of microRNAs to regulate key cellular processes and nanotherapy, which enables precise drug delivery to the central nervous system, is analyzed. Despite promising advances in these strategies, the incidence of Alzheimer's disease continues to rise. Therefore, it is proposed that achieving effective treatment in the future may require the integration of combined approaches, maximizing the synergistic effects of different therapeutic interventions.

The Crucial Role of the Blood-Brain Barrier in Neurodegenerative Diseases: Mechanisms of Disruption and Therapeutic Implications

The blood-brain barrier (BBB) is a crucial structure that maintains brain homeostasis by regulating the entry of molecules and cells from the bloodstream into the central nervous system (CNS). Neurodegenerative diseases such as Alzheimer's and Parkinson's disease, as well as ischemic stroke, compromise the integrity of the BBB. This leads to increased permeability and the infiltration of harmful substances, thereby accelerating neurodegeneration. In this review, we explore the mechanisms underlying BBB disruption, including oxidative stress, neuroinflammation, vascular dysfunction, and the loss of tight junction integrity, in patients with neurodegenerative diseases. We discuss how BBB breakdown contributes to neuroinflammation, neurotoxicity, and the abnormal accumulation of pathological proteins, all of which exacerbate neuronal damage and facilitate disease progression. Furthermore, we discuss potential therapeutic strategies aimed at preserving or restoring BBB function, such as anti-inflammatory treatments, antioxidant therapies, and approaches to enhance tight junction integrity. Given the central role of the BBB in neurodegeneration, maintaining its integrity represents a promising therapeutic approach to slow or prevent the progression of neurodegenerative diseases.

Astrocytes phenomics as new druggable targets in healthy aging and Alzheimer's disease progression

For over a century after their discovery astrocytes were regarded merely as cells located among other brain cells to hold and give support to neurons. Astrocytes activation, "astrocytosis" or A1 functional state, was considered a detrimental mechanism against neuronal survival. Recently, the scientific view on astrocytes has changed. Accumulating evidence indicate that astrocytes are not homogeneous, but rather encompass heterogeneous subpopulations of cells that differ from each other in terms of transcriptomics, molecular signature, function and response in physiological and pathological conditions. In this review, we report and discuss the recent literature on the phenomic differences of astrocytes in health and their modifications in disease conditions, focusing mainly on the hippocampus, a region involved in learning and memory encoding, in the age-related memory impairments, and in Alzheimer's disease (AD) dementia. The morphological and functional heterogeneity of astrocytes in different brain regions may be related to their different housekeeping functions. Astrocytes that express diverse transcriptomics and phenomics are present in strictly correlated brain regions and they are likely responsible for interactions essential for the formation of the specialized neural circuits that drive complex behaviors. In the contiguous and interconnected hippocampal areas CA1 and CA3, astrocytes show different, finely regulated, and region-specific heterogeneity. Heterogeneous astrocytes have specific activities in the healthy brain, and respond differently to physiological or pathological stimuli, such as inflammaging present in normal brain aging or beta-amyloid-dependent neuroinflammation typical of AD. To become reactive, astrocytes undergo transcriptional, functional, and morphological changes that transform them into cells with different properties and functions. Alterations of astrocytes affect the neurovascular unit, the blood-brain barrier and reverberate to other brain cell populations, favoring or dysregulating their activities. It will be of great interest to understand whether the differential phenomics of astrocytes in health and disease can explain the diverse vulnerability of the hippocampal areas to aging or to different damaging insults, in order to find new astrocyte-targeted therapies that might prevent or treat neurodegenerative disorders.

Roles of the Receptor for Advanced Glycation End Products and Its Ligands in the Pathogenesis of Alzheimer's Disease

The Receptor for Advanced Glycation End Products (RAGE), part of the immunoglobulin superfamily, plays a significant role in various essential functions under both normal and pathological conditions, especially in the progression of Alzheimer's disease (AD). RAGE engages with several damage-associated molecular patterns (DAMPs), including advanced glycation end products (AGEs), beta-amyloid peptide (Aβ), high mobility group box 1 (HMGB1), and S100 calcium-binding proteins. This interaction impairs the brain's ability to clear Aβ, resulting in increased Aβ accumulation, neuronal injury, and mitochondrial dysfunction. This further promotes inflammatory responses and oxidative stress, ultimately leading to a range of age-related diseases. Given RAGE's significant role in AD, inhibitors that target RAGE and its ligands hold promise as new strategies for treating AD, offering new possibilities for alleviating and treating this serious neurodegenerative disease. This article reviews the various pathogenic mechanisms of AD and summarizes the literature on the interaction between RAGE and its ligands in various AD-related pathological processes, with a particular focus on the evidence and mechanisms by which RAGE interactions with AGEs, HMGB1, Aβ, and S100 proteins induce cognitive impairment in AD. Furthermore, the article discusses the principles of action of RAGE inhibitors and inhibitors targeting RAGE-ligand interactions, along with relevant clinical trials.

Cycloastragenol promotes dorsal column axon regeneration in mice

Introduction

Cycloastragenol (CAG) has a wide range of pharmacological effects, including anti-inflammatory, antiaging, antioxidative, and antitumorigenic properties. In addition, our previous study showed that CAG administration can promote axonal regeneration in peripheral neurons. However, whether CAG can activate axon regeneration central nervous system (CNS) remains unknown.

Methods

Here, we established a novel mouse model for visualizing spinal cord dorsal column axon regeneration involving the injection of AAV2/9-Cre into the lumbar 4/5 dorsal root ganglion (DRG) of Rosa-tdTomato reporter mice. We then treated mice by intraperitoneal administration of CAG.

Results

Our results showed that intraperitoneal CAG injections significantly promoted the growth of vitro-cultured DRG axons as well as the growth of dorsal column axons over the injury site in spinal cord injury (SCI) mice. Our results further indicate that CAG administration can promote the recovery of sensory and urinary function in SCI mice.

Conclusion

Together, our findings highlight the therapeutic potential of CAG in spinal cord injury repair.

Microgel-encapsulated tetrandrine nanoparticles promote spinal cord repair by sustaining neuroinflammation inhibition

Traumatic spinal cord injury (SCI) initiates an intricate secondary injury cascade, characterized by persistent inflammatory responses with neurotoxic microglia and astrocyte activation. Inhibition of neuroinflammation would significantly benefit SCI treatment. Here, tetrandrine with anti-neuroinflammatory activity was delivered into the intrathecal space for SCI treatment. The tetrandrine was encapsulated in MPEG-PDLLA nanoparticles and further loaded into GelMA microgels via a fast 3D printing process based on digital light. After intrathecal injection, the drug-loaded microgels could sustain the release of tetrandrine in the intrathecal space, resulting in efficient repair of the injured spinal cord with recovery of function. Its mechanisms were associated with the modulation of neurotoxic microglia and astrocytes as well as their crosstalk. This work demonstrates a tetrandrine-loaded microgel with potential application in SCI treatment via sustained inhibition of neuroinflammation.

Flavaglines with anti-neuroinflammatory activity from Aglaia edulis (Roxb.) Wall. and structure revision of related flavaglines

Eight cyclopenta[b]benzofurans (1, 2, 4, and 5-9) and eight cyclopenta[bc]benzopyrans (3, 10-16), including a revised (4) and three undescribed compounds (1-3), were isolated from the twigs and leaves of Aglaia edulis (Roxb.) Wall. Their structures were determined by a combination of spectral analysis in conjunction with NMR and ECD calculations. Moreover, based on the findings from 13C NMR calculations and DP4+ statistical analysis, an empirical guideline was established to differentiate the structures of cyclopenta[bc]benzopyrans and cyclopenta[b]benzofurans by aggregating chemical shift data from known compounds. This guideline facilitated the proposal of structural revisions for three previously reported analogs (R-1, R-2, R-3). Biological assay indicated that cyclopenta[b]benzofuran flavalines (2, and 4-8) could significantly inhibit NO production in LPS-induced BV-2 cells with IC50 values from 0.002 to 0.05 μM.

Melatonin attenuates intermittent hypoxia-induced cognitive impairment in aged mice: The role of inflammation and synaptic plasticity

Intermittent hypoxia (IH), a major pathophysiologic alteration in obstructive sleep apnea syndrome (OSAS), is an important contributor to cognitive impairment. Increasing research suggests that melatonin has anti-inflammatory properties and improves functions related to synaptic plasticity. However, it is unclear whether melatonin has a protective effect against OSAS-induced cognitive dysfunction in aged individuals and the involved mechanisms are also unclear. Therefore, in the study, the effects of exposure to IH alone and IH in combination with daily melatonin treatment were investigated in C57BL/6 J mice aged 18 months. Assessment of the cognitive ability of mice in a Morris water maze showed that melatonin attenuated IH-induced impairment of learning and memory in aged mice. Enzyme-linked immunosorbent assay, polymerase chain reaction, and western blotting molecular techniques showed that melatonin treatment reduced the levels of the proinflammatory cytokines, interleukin-1β, interleukin-6, and tumor necrosis factor-α, decreased the levels of NOD-like receptor thermal protein domain associated protein 3 and nuclear factor kappa-B, lowered the levels of ionized calcium-binding adapter molecule 1 and glial fibrillary acidic protein, and increased the levels of the synaptic proteins, activity-regulated cytoskeleton-associated protein, growth-associated protein-43, postsynaptic density protein 95, and synaptophysin in IH-exposed mice. Moreover, electrophysiological results showed that melatonin ameliorated the decline in long-term potentiation induced by IH. The results suggest that melatonin can ameliorate IH-induced cognitive deficits by inhibiting neuroinflammation and improving synaptic plasticity in aged mice.

From Skin and Gut to the Brain: The Infectious Journey of the Human Commensal Fungus Malassezia and Its Neurological Consequences

The human mycobiome encompasses diverse communities of fungal organisms residing within the body and has emerged as a critical player in shaping health and disease. While extensive research has focused on the skin and gut mycobiome, recent investigations have pointed toward the potential role of fungal organisms in neurological disorders. Among those fungal organisms, the presence of the commensal fungus Malassezia in the brain has created curiosity because of its commensal nature and primary association with the human skin and gut. This budding yeast is responsible for several diseases, such as Seborrheic dermatitis, Atopic dermatitis, Pityriasis versicolor, Malassezia folliculitis, dandruff, and others. However recent findings surprisingly show the presence of Malassezia DNA in the brain and have been linked to diseases like Alzheimer's disease, Parkinson's disease, Multiple sclerosis, and Amyotrophic lateral sclerosis. The exact role of Malassezia in these disorders is unknown, but its ability to infect human cells, travel through the bloodstream, cross the blood-brain barrier, and reside along with the lipid-rich neuronal cells are potential mechanisms responsible for pathogenesis. This also includes the induction of pro-inflammatory cytokines, disruption of the blood-brain barrier, gut-microbe interaction, and accumulation of metabolic changes in the brain environment. In this review, we discuss these key findings from studies linking Malassezia to neurological disorders, emphasizing the complex and multifaceted nature of these cases. Furthermore, we discuss potential mechanisms through which Malassezia might contribute to the development of neurological conditions. Future investigations will open up new avenues for our understanding of the fungal gut-brain axis and how it influences human behavior. Collaborative research efforts among microbiologists, neuroscientists, immunologists, and clinicians hold promise for unraveling the enigmatic connections between human commensal Malassezia and neurological disorders.

Crotalaria quinquefolia L. Revealed as a Potential Source of Neuropharmacophore in Both Experimental and Computational Studies

Herbal remedies have shown great promise for improving human health. The plant Crotalaria quinquefolia is used in folk medicine to cure different diseases, including scabies, fever, discomfort, and lung infections. The present research was designed to explore bioactive compounds and evaluate the neuropharmacological effects of C. quinquefolia extract through in vivo and in silico approaches. Different secondary metabolites as well as the antioxidant activity were measured. Furthermore, chemical compounds were identified by HPLC and GCMS analysis. The neuropharmacological activity was examined by hole cross, hole board, open field, Y-maze, elevated plus maze, and thiopental sodium induced sleeping time tests in mice at doses of 100 mg/kg and 200 mg/kg b.w. (p.o). Besides, an in-silico study was performed on proteins related to Alzheimer disease. The extract showed a significant content of secondary metabolites and antioxidant potential. The in-silico analysis showed that myricetin, quercetin, rutin, and kaempferol have good binding affinity with studied proteins, and QSAR studies revealed potential benefits for treating dementia, and age-related macular degeneration. The findings of the present neurological activity collectively imply that the extract has strong CNS depressant and anxiolytic activity. Therefore, C. quinquefolia can be a potential source of compounds to treat Alzheimer disease.

Investigating the Impact of IL-6 and CXCL8 on Neurodegeneration and Cognitive Decline in Alzheimer Disease

BACKGROUND

Alzheimer disease (AD) is a progressive neurodegenerative disorder primarily affecting the elderly, characterized by severe cognitive impairment and memory loss. Emerging evidence suggests that neuroinflammation plays a significant role in AD pathogenesis, with cytokines like interleukin-6 (IL-6) and C-X-C motif chemokine ligand 8 (CXCL8) contributing to the disease progression.

METHODS

We utilized Gene Expression Omnibus datasets to identify IL-6 and CXCL8 as pivotal inflammatory markers in AD. In vitro experiments were conducted using SK-N-BE(2)-M17 and THP-1 cell lines treated with IL-6 and CXCL8 to model AD. Additionally, in vivo tests on Amyloid Precursor Protein/Presenilin 1 (APP/PS1) AD mouse models were performed to assess the impact of these cytokines on cognitive functions and brain pathology.

RESULTS

The results indicated a significant decrease in cell viability, increased apoptosis, and elevated inflammatory factor secretion following IL-6 and CXCL8 treatment in vitro. In vivo, AD mouse models treated with these cytokines exhibited exacerbated emotional distress, decreased social interaction, impaired cognitive functions, and increased amyloid protein deposition in neural tissues.

CONCLUSIONS

The study highlights the detrimental effects of IL-6 and CXCL8 on neuronal health and cognitive functions in AD. These findings suggest that targeting these cytokines could offer potential therapeutic interventions for improving patient outcomes in Alzheimer disease.

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.

Anisomycin alleviates cognitive impairments and pathological features in 3xTg-AD mice

Neuroinflammation plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). Anisomycin is a pyrrolidine antibiotic isolated from Streptomyces griseolus, which is an efficient anti-inflammatory agent that functions both in vivo and in vitro. However, it is not clear whether anisomycin can exert neuroprotective effect in AD. In the present study, anisomycin was intragastrically administrated to female triple-transgenic AD (3xTg-AD) model mice, then Morris water maze test was used to observe the long-term spatial memory of mice, the in vivo hippocampal field potential recording was performed to evaluate the synaptic plasticity, the Western blot and immunofluorescence were employed to detect pathological changes, and the bioinformatics analysis was used to predict the potential target of anisomycin exerting effects in AD. The results showed that anisomycin ameliorated the long-term spatial memory deficits, improved LTP depression and increased the expression of PSD-95, reduced the Aβ and tau pathologies, and alleviated the activation of microglia and astrocytes in the brains of 3xTg-AD mice. In addition, the results from bioinformatics analysis showed that the potential target of anisomycin focused on inflammatory pathway. These results indicated that anisomycin exerts neuroprotective effects in 3xTg-AD mice by alleviating neuroinflammation, but the potential mechanism of anisomycin exerting neuroprotective effects needs to be further investigated.

Role of NRF2 in Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is a polygenic, multifactorial neurodegenerative disorder and remains the most prevalent form of dementia, globally. Despite decades of research efforts, there is still no effective cure for this debilitating condition. AD research has increasingly focused on transcription factor NRF2 (nuclear factor erythroid 2-related factor 2) as a potential therapeutic target. NRF2 plays a crucial role in protecting cells and tissues from environmental stressors, such as electrophiles and reactive oxygen species. Recently, an increasing number of studies have demonstrated that NRF2 is a key regulator in AD pathology. NRF2 is highly expressed in microglia, resident macrophages in the central nervous system, and contributes to neuroinflammation, phagocytosis and neurodegeneration in AD. NRF2 has been reported to modulate microglia-induced inflammation and facilitate the transition from homeostatic microglia to a disease-associated microglia subset. Genetic and pharmacological activation of NRF2 has been demonstrated to improve cognitive function. Here, we review the current understanding of the involvement of NRF2 in AD and the critical role that NRF2 plays in microglia in the context of AD. Our aim is to highlight the potential of targeting NRF2 in the microglia as a promising therapeutic strategy for mitigating the progression of AD.

The Aβ42:Aβ40 ratio modulates aggregation in beta-amyloid oligomers and drives metabolic changes and cellular dysfunction

The pathophysiological role of Aβ42 oligomers in the onset of Alzheimer's disease (AD) is heavily disputed, pivoting research toward investigating mixed oligomers composed of Aβ42 and Aβ40, which is more abundant but less aggregation-prone. This study investigates Aβ42:Aβ40 oligomers in different ratios, examining their adverse effects on endothelial cells, neurons, astroglia, and microglia, as well as in a human blood-brain barrier (BBB) model. Combining label-free Raman microscopy with complementary imaging techniques and biochemical assays, we show the prominent impact of Aβ40 on Aβ42 fibrillation, suggesting an inhibitory effect on aggregation. Mixed oligomers, especially with low proportions of Aβ42, were equally detrimental as pure Aβ42 oligomers regarding cell viability, functionality, and metabolism. They also differentially affected lipid droplet metabolism in BBB-associated microglia, indicating distinct pathophysiological responses. Our findings demonstrate the overarching significance of the Aβ42:Aβ40 ratio in Aβ oligomers, challenging the traditional focus on Aβ42 in AD research.

Piezo1 activation on microglial cells exacerbates demyelination in sepsis by influencing the CCL25/GRP78 pathway

BACKGROUND

In sepsis-associated encephalopathy (SAE), the activation of microglial cells and ensuing neuroinflammation are important in the underlying pathological mechanisms. Increasing evidence suggests that the protein Piezo1 functions as a significant regulator of neuroinflammation. However, the influence of Piezo1 on microglial cells in the context of SAE has not yet been determined. This study aims to investigate the role of Piezo1 in microglial cells in the context of SAE.

METHODS

By inducing cecal ligation and puncture (CLP), a mouse model of SAE was established, while the control group underwent a sham surgery in which the cecum was exposed without ligation and puncture. Piezo1 knockout mice were employed in this study. Morris water maze tests were conducted between Days 14 and 18 postop to assess both the motor activity and cognitive function. A proteomic analysis was conducted to assess the SAE-related pathways, whereas a Mendelian randomization analysis was conducted to identify the pathways associated with cognitive impairment. Dual-label immunofluorescence and flow cytometry were used to assess the secretion of inflammatory factors, microglial status, and oligodendrocyte development. Electron microscopy was used to evaluate axonal myelination. A western blot analysis was conducted to evaluate the influence of Piezo1 on oligodendrocyte ferroptosis.

RESULTS

The results of the bioinformatics analysis have revealed the significant involvement of CCL25 in the onset and progression of SAE-induced cognitive impairment. SAE leads to cognitive dysfunction by activating the microglial cells. The release of CCL25 by the activated microglia initiates the demyelination of oligodendrocytes in the hippocampus, resulting in ferroptosis and the disruption of hippocampal functional connectivity. Of note, the genetic knockout of the Piezo1 gene mitigates these changes. The treatment with siRNA targeting Piezo1 effectively reduces the secretion of inflammatory mediators CCL25 and IL-18 by inhibiting the p38 pathway, thus preventing the ferroptosis of oligodendrocytes through the modulation of the CCL25/GPR78 axis.

CONCLUSION

Piezo1 is involved in the activation of microglia and demyelinating oligodendrocytes in the animal models of SAE, resulting in cognitive impairment. Consequently, targeting Piezo1 suppression can be a promising approach for therapeutic interventions aimed at addressing cognitive dysfunction associated with SAE.

Exploring therapeutic potential: Targeting TRPM7 in neurodegenerative diseases

The ions Ca2+ and Mg2+, which are both present in the body, have been demonstrated to be crucial in the control of a variety of neuronal processes. Transient melastatin-7 (TRPM7) channel plays an important role in controlling Ca2+ and Mg2+ homeostasis, which is crucial for biological processes. The review will also examine how changes in TRPM7 function or expression can lead to neurodegeneration.Even though eight different TRPM channels have been found so far, the channel properties, activation mechanisms, and physiological responses exhibited by these channels can vary greatly from one another. Only TRPM6 and TRPM7 out of the eight TRPM channels were found to have a high permeability to both Ca2+ and Mg2+. In contrast to TRPM6 channels, which are not highly expressed in neuronal cells, TRPM7 channels are widely distributed throughout the nervous system, so they will be the sole focus of this article. It is possible that, in the future, for the treatment of neurodegenerative disorder new therapeutic drug targets will be developed as a direct result of research into the specific roles played by TRPM7 channels in several different neurodegenerative conditions as well as the factors that are responsible for TRPM7 channel regulation.

Glutamate: Molecular Mechanisms and Signaling Pathway in Alzheimer's Disease, a Potential Therapeutic Target

Gamma-glutamate is an important excitatory neurotransmitter in the central nervous system (CNS), which plays an important role in transmitting synapses, plasticity, and other brain activities. Nevertheless, alterations in the glutamatergic signaling pathway are now accepted as a central element in Alzheimer's disease (AD) pathophysiology. One of the most prevalent types of dementia in older adults is AD, a progressive neurodegenerative illness brought on by a persistent decline in cognitive function. Since AD has been shown to be multifactorial, a variety of pharmaceutical targets may be used to treat the condition. N-methyl-D-aspartic acid receptor (NMDAR) antagonists and acetylcholinesterase inhibitors (AChEIs) are two drug classes that the Food and Drug Administration has authorized for the treatment of AD. The AChEIs approved to treat AD are galantamine, donepezil, and rivastigmine. However, memantine is the only non-competitive NMDAR antagonist that has been authorized for the treatment of AD. This review aims to outline the involvement of glutamate (GLU) at the molecular level and the signaling pathways that are associated with AD to demonstrate the drug target therapeutic potential of glutamate and its receptor. We will also consider the opinion of the leading authorities working in this area, the drawback of the existing therapeutic strategies, and the direction for the further investigation.

Modulation of the central nervous system immune response and neuroinflammation via Wnt signaling in health and neurodegenerative diseases

The immune response in the central nervous system (CNS) is a highly specialized and tightly regulated process essential for maintaining neural health and protecting against pathogens and injuries. The primary immune cells within the CNS include microglia, astrocytes, T cells, and B cells. They work together, continuously monitor the CNS environment for signs of infection, injury, or disease, and respond by phagocytosing debris, releasing cytokines, and recruiting other immune cells. In addition to providing neuroprotection, these immune responses must be carefully balanced to prevent excessive inflammation that can lead to neuronal damage and contribute to neurodegenerative diseases. Dysregulated immune responses in the CNS are implicated in various neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Wnt signaling is a crucial pathway in the CNS that regulates various cellular processes critical for brain development, function, and maintenance. Despite enhancing immune responses in the health CNS, dysregulated Wnt signaling exacerbates neuroinflammation in the neurodegenerative brains. This review summarized the role of Wnt signaling in regulating immune response under different conditions. We then examined the role of immune response in healthy brains and during the development of neurodegenerative diseases. We also discussed therapeutic intervention in various neurodegenerative diseases through the modulation of the Wnt signaling pathway and neuroinflammation and highlighted challenges and limitations in current clinical trials.

Progress in the mechanisms of pain associated with neurodegenerative diseases

Neurodegenerative diseases (NDDs) represent a class of neurological disorders characterized by the progressive degeneration or loss of neurons, impacting millions of individuals globally. In addition to the typical manifestations, pain is a prevalent symptom associated with NDDs, seriously impacting the quality of life for patients. The pathogenesis of pain associated with NDDs is intricate and multifaceted. Currently, the clinical management of NDDs-related pain symptoms predominantly relies on conventional pharmacological agents or physical therapy. However, these approaches often fail to produce satisfactory outcomes. This article summarizes the underlying mechanisms of major NDDs-associated pain: Neuroinflammation, Brain and spinal cord dysfunctions, Mitochondrial dysfunction, Risk gene and pathological protein, as well as Receptor, channel, and neurotransmitter. While numerous studies have investigated the downstream pathological processes associated with these mechanisms, there remains a significant gap in identifying the key initiating factors. Specifically, there is insufficient evidence for the upstream elements that activate microglia and astrocytes in neuroinflammation leading to pain in NDDs. Likewise, there is an absence of upstream factors elucidating how dysfunctions in the brain and spinal cord, as well as mitochondrial impairments, contribute to the development of pain. Furthermore, the specific mechanisms through which hallmark pathological proteins related to NDDs contribute to these pathological processes remain inadequately understood. The objective of this article is to synthesize the existing mechanisms underlying pain associated with NDDs, including Alzheimer's disease, Parkinson's disease, Huntington's disease, Schizophrenia, Amyotrophic lateral sclerosis, and Multiple sclerosis, while also identifying gaps and deficiencies in these mechanisms. This paper offers insights for future research trajectories. Given the intricate pathogenesis of NDDs-related pain, it emphasizes that a promising short-term strategy is combination therapy-intervening concurrently in multiple pathological processes-akin to the cocktail approach utilized in treating acquired immunodeficiency syndrome (AIDS). For long-term advancements, achieving breakthroughs in the treatment of the NDDs themselves will remain essential for alleviating accompanying pain symptoms.

Rotating magnetic field improved cognitive and memory impairments in a sporadic ad model of mice by regulating microglial polarization

Neuroinflammation, triggered by aberrantly activated microglia, is widely recognized as a key contributor to the initiation and progression of Alzheimer's disease (AD). Microglial activation in the central nervous system (CNS) can be classified into two distinct phenotypes: the pro-inflammatory M1 phenotype and the anti-inflammatory M2 phenotype. In this study, we investigated the effects of a non-invasive rotating magnetic field (RMF) (0.2T, 4Hz) on cognitive and memory impairments in a sporadic AD model of female Kunming mice induced by AlCl3 and D-gal. Our findings revealed significant improvements in cognitive and memory impairments following RMF treatment. Furthermore, RMF treatment led to reduced amyloid-beta (Aβ) deposition, mitigated damage to hippocampal morphology, prevented synaptic and neuronal loss, and alleviated cell apoptosis in the hippocampus and cortex of AD mice. Notably, RMF treatment ameliorated neuroinflammation, facilitated the transition of microglial polarization from M1 to M2, and inhibited the NF-кB/MAPK pathway. Additionally, RMF treatment resulted in reduced aluminum deposition in the brains of AD mice. In cellular experiments, RMF promoted the M1-M2 polarization transition and enhanced amyloid phagocytosis in cultured BV2 cells while inhibiting the TLR4/NF-кB/MAPK pathway. Collectively, these results demonstrate that RMF improves memory and cognitive impairments in a sporadic AD model, potentially by promoting the M1 to M2 transition of microglial polarization through inhibition of the NF-кB/MAPK signaling pathway. These findings suggest the promising therapeutic applications of RMF in the clinical treatment of AD.

Identification and verification of key molecules in the epileptogenic process of focal cortical dysplasia

Focal cortical dysplasia (FCD) represents a common developmental malformation associated with drug-resistant epilepsy (DRE) among children. However, the exact molecular mechanisms behind this condition are still unclear. In our study, FCD-associated microarray data from the Gene Expression Omnibus (GEO) database were analyzed. A comprehensive series of bioinformatics analyses were conducted, including screening for differentially expressed genes (DEGs), functional enrichment analysis, weighted gene co-expression network analysis (WGCNA), and protein-protein interaction (PPI) analysis. Subsequently, a freezing lesion (FL) rat model was developed to validate expression levels of hub genes along with the molecular pathways behind FCD epileptogenicity. 320 DEGs were identified, and functional enrichment analysis revealed significant enrichment of these DEGs in "Neuroinflammatory response", "Cytokine production involved in immune response", and "Macrophage activation". Ultimately, 5 potential hub genes (CYBB, ITGAM, FCG3A, LY86, and CD86) were pinpointed. Notably, 4 hub genes (CYBB, ITGAM, FCG3A, and CD86) were validated in in vivo experiments, suggesting possible associations with neuroinflammation triggered by microglia. This underscores the tight relationship between microglia-induced neuroinflammation and the pathological progression of epileptic seizures in FCD. ITGAM, FCG3A, CD86, CYBB, and LY86 may emerge as promising candidate biomarkers, influencing diagnostic and therapeutic strategies.

Exploring the feasibility of using mice as a substitute model for investigating microglia in aging and Alzheimer's disease though single cell analysis

OBJECTIVE

To guide animal experiments, we investigated the similarities and differences between humans and mice in aging and Alzheimer's disease (AD) at the single-nucleus RNA sequencing (snRNA-seq) or single-cell RNA sequencing (scRNA-seq) level.

METHODS

Microglia cells were extracted from dataset GSE198323 of human post-mortem hippocampus. The distributions and proportions of microglia subpopulation cell numbers related to AD or age were compared. This comparison was done between GSE198323 for humans and GSE127892 for mice, respectively. The Seurat R package and harmony R package were used for data analysis and batch effect correction. Differentially expressed genes (DEGs) were identified by FindMarkers function with MAST test. Comparative analyses were conducted on shared genes in DEGs associated with age and AD. The analyses were done between human and mouse using various bioinformatics techniques. The analysis of genes in DEGs related to age was conducted. Similarly, the analysis of genes in DEGs related to AD was performed. Cross-species analyses were conducted using orthologous genes. Comparative analyses of pseudotime between humans and mice were performed using Monocle2.

RESULTS

(1) Similarities: The proportion of microglial subpopulation Cell_APOE/Apoe shows consistent trends, whether in AD or normal control (NC) groups in both humans and mice. The proportion of Cell_CX3CR1/Cx3cr1, representing homeostatic microglia, remains stable with age in NC groups across species. Tuberculosis and Fc gamma R-mediated phagocytosis pathways are shared in microglia responses to age and AD across species, respectively. (2) Differences: IL1RAPL1 and SPP1 as marker genes are more identifiable in human microglia compared to their mouse counterparts. Most genes of DEGs associated with age or AD exhibit different trends between humans and mice. Pseudotime analyses demonstrate varying cell density trends in microglial subpopulations, depending on age or AD across species.

CONCLUSIONS

Mouse Apoe and Cell_Apoe maybe serve as proxies for studying human AD, while Cx3cr1 and Cell_Cx3cr1 are suitable for human aging studies. However, AD mouse models (App_NL_G_F) have limitations in studying human genes like IL1RAPL1 and SPP1 related to AD. Thus, mouse models cannot fully replace human samples for AD and aging research.

Neurotrophic Effects of Foeniculum vulgare Ethanol Extracts on Hippocampal Neurons: Role of Anethole in Neurite Outgrowth and Synaptic Development

Foeniculum vulgare Mill, commonly known as fennel, is an aromatic herb traditionally used for culinary and medicinal purposes, with potential therapeutic effects on neurological disorders. However, limited research has focused on its neurotrophic impact, particularly on neuronal maturation and synaptic development. This study investigates the neurotrophic effects of F. vulgare ethanol extracts (FVSE) on the maturation of rat primary hippocampal neurons. Results show that FVSE and its prominent component, anethole, significantly promote neurite outgrowth in a dose-dependent manner. Optimal axonal and dendritic growth occurred at concentrations of 40 µg/mL FVSE and 20 µM anethole, respectively, without causing cytotoxicity, underscoring the safety of FVSE for neuronal health. Additionally, FVSE enhances the formation of synapses, essential for neuronal communication. Network pharmacology analysis revealed that FVSE components influence critical neurotrophic pathways, including PI3K-AKT and Alzheimer's disease pathways. Specifically, FVSE modulates key proteins, including tropomyosin receptor kinase (Trk), glycogen synthase kinase 3 (GSK3βser9), phosphatidylinositol 3-kinase (PI3K), and extracellular signal-regulated protein kinase (Erk1/2). Anethole was found to play a key role in regulating these pathways, which was confirmed by immunocytochemistry experiments demonstrating its effect on promoting neuronal growth and synaptic development. In conclusion, this study highlights the neurotrophic properties of FVSE, with anethole emerging as a critical bioactive compound. These findings provide valuable insights into the therapeutic potential of fennel in treating neurological disorders, offering a basis for future research into interventions promoting neuronal growth and survival.

The Neural Palette of Heme: Altered Heme Homeostasis Underlies Defective Neurotransmission, Increased Oxidative Stress, and Disease Pathogenesis

Heme, a complex iron-containing molecule, is traditionally recognized for its pivotal role in oxygen transport and cellular respiration. However, emerging research has illuminated its multifaceted functions in the nervous system, extending beyond its canonical roles. This review delves into the diverse roles of heme in the nervous system, highlighting its involvement in neural development, neurotransmission, and neuroprotection. We discuss the molecular mechanisms by which heme modulates neuronal activity and synaptic plasticity, emphasizing its influence on ion channels and neurotransmitter receptors. Additionally, the review explores the potential neuroprotective properties of heme, examining its role in mitigating oxidative stress, including mitochondrial oxidative stress, and its implications in neurodegenerative diseases. Furthermore, we address the pathological consequences of heme dysregulation, linking it to conditions such as Alzheimer's disease, Parkinson's disease, and traumatic brain injuries. By providing a comprehensive overview of heme's multifunctional roles in the nervous system, this review underscores its significance as a potential therapeutic target and diagnostic biomarker for various neurological disorders.

Microglia-Associated Neuroinflammation in Alzheimer’s Disease and Its Therapeutic Potential

Background: Neuroinflammation has long been implicated in the progression of amyloid beta (Aβ) accumulation and the decline of cognitive function in Alzheimer’s disease (AD). The phenotype balance between A1 (toxic) and A2 (safe) microglial phenotypes to toxic illness in AD has become a hot research topic at present. Currently, many transcription factors, downstream signaling pathways, and molecular mechanisms that regulate the polarization of microglia are being explored. Furthermore, microglia may also exert a complex role in AD through the transformation of Aβ plaques or debris clearance, reflected in Aβ phagocytosis. One of the mediators of neuroinflammation in AD is the activated microglia. Therefore, the regulation of microglial function may be the key to successfully treating AD. Methods: This paper is a review article. PubMed, Embase, Scopus, and research meeting abstracts were searched up to 2024 for studies of microglia and neuroinflammation in Alzheimer’s Disease. Systematic information retrieval was performed, and appropriate studies were isolated based on important information available in the studies. The information from each of the articles was understood and extracted to form a database. Results: The similar neuropathological results between several animals and AD cases show the possibility of implementing microglia-related changes as an earlier diagnostic marker for AD in humans. The gene sets identified in various transcriptomic studies further foster this avenue of research by offering potential targets for therapeutic development. Substantial evidence, both in vitro and in vivo, has suggested that the loss of the normal A2 phenotype and the activation of toxic A1 microglia contribute to neurodegeneration in AD. Conclusions: Promoting or restoring the polarization of microglia towards the A2 phenotype may thus represent an effective therapeutic strategy for ameliorating neuroinflammation and progressive neurocognitive impairments. Multiple studies suggest that microglia-associated neuroinflammation at a special stage could also be protective, and, therefore, intervention should be delicate so that a beneficial response is retained.

Jiawei Qifuyin Enhances Immunity and Improves Cognitive Impairment in APP/PS1 Mice Through Modulation of Neuroinflammatory Pathways

Purpose

To explore the protective effects and mechanisms of Jiawei Qifuyin on APP/PS1 mice, a model for Alzheimer's disease (AD).

Methods

Network pharmacology tools were used to predict anti-AD targets and signaling pathways affected by Jiawei Qifuyin. In vitro studies assessed antioxidant and oxygen radical scavenging abilities, immune cell proliferation, and inflammatory cytokine levels in lipopolysaccharide-induced BV2 microglial cells. Cognitive ability in APP/PS1 mice was evaluated using the Morris Water Maze test. mRNA expression of neuroinflammatory factors, changes in intestinal microbiota, and short-chain fatty acid content were analyzed post-treatment.

Results

Network pharmacology predicted that Jiawei Qifuyin affects AKT1, TNF-α, and AGE/RAGE pathways. It showed concentration-dependent antioxidant effects and modulated immune cell proliferation. IL-2, IL-6, and TNF-α levels in LPS-induced BV2 cells were significantly reduced. Treated animals exhibited improved cognitive performance, decreased brain amyloid-beta levels, and downregulated expression of IL-1β, IL-6, RAGE, and NF-κB. Significant changes in intestinal microbiota composition and SCFA content were observed.

Conclusion

Jiawei Qifuyin may enhance immunity and improve cognitive impairment in APP/PS1 mice through regulation of inflammatory factors, gut microbiota, and the gut-brain axis.

Design, synthesis, and biological evaluation of imidazolylacetophenone oxime derivatives as novel brain-penetrant agents for Alzheimer's disease treatment

Alzheimer's disease (AD, also known as dementia) has become a serious global health problem along with population aging, and neuroinflammation is the underlying cause of cognitive impairment in the brain. Nowadays, the development of multitarget anti-AD drugs is considered to be one effective approach. Imidazolylacetophenone oxime ethers or esters (IOEs) were multifunctional agents with neuroinflammation inhibition, metal chelation, antioxidant and neuroprotection properties against Alzheimer's disease. In this study, IOEs derivatives 1-8 were obtained by structural modifications of the oxime and imidazole groups, and the SARs showed that (Z)-oxime ether (derivative 2) had stronger anti-neuroinflammatory and neuroprotective ability than (E)-congener. Then, IOEs derivatives 9-30 were synthesized based on target-directed ligands and activity-based groups hybridization strategy. In vitro anti-AD activity screening revealed that some derivatives exhibited potentially multifunctional effects, among which derivative 28 exhibited the strongest inhibitory activity on NO production with EC50 value of 0.49 μM, and had neuroprotective effects on 6-OHDA-induced cell damage and RSL3-induced ferroptosis. The anti-neuroinflammatory mechanism showed that 28 could inhibit the release of pro-inflammatory factors PGE2 and TNF-α, down-regulate the expression of iNOS and COX-2 proteins, and promote the polarization of BV-2 cells from pro-inflammatory M1 phenotype to anti-inflammatory M2 phenotype. In addition, 28 can dose-dependently inhibit acetylcholinesterase (AChE) and Aβ42 aggregation. Moreover, the selected nuclide [18F]-labeled 28 was synthesized to explore its biodistribution by micro-PET/CT, of which 28 can penetrate the blood-brain barrier (BBB). These results shed light on the potential of 28 as a new multifunctional candidate for AD treatment.

Functional Food Nutrients, Redox Resilience Signaling and Neurosteroids for Brain Health

The interplay between functional food nutrients and neurosteroids has garnered significant attention for its potential to enhance stress resilience in health and/or disease. Several bioactive nutrients, including medicinal herbs, flavonoids, and bioavailable polyphenol-combined nanoparticles, as well as probiotics, vitamin D and omega-3 fatty acids, have been shown to improve blood-brain barrier (BBB) dysfunction, endogenous neurosteroid homeostasis and brain function. These nutrients can inhibit oxidative stress and neuroinflammation, which are linked to the pathogenesis of various neurological disorders. Interestingly, flavonoids exhibit dose-dependent effects, activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway at the physiological/low dose (neurohormesis). This leads to the upregulation of antioxidant phase II genes and proteins such as heme oxygenase-1 (HO-1) and sirtuin-1 (Sirt1), which are activated by curcumin and resveratrol, respectively. These adaptive neuronal response mechanisms help protect against reactive oxygen species (ROS) and neurotoxicity. Impaired Nrf2 and neurosteroid hormone signaling in the brain can exacerbate selective vulnerability to neuroinflammatory conditions, contributing to the onset and progression of neurodegenerative and psychiatric disorders, including Alzheimer's disease, anxiety and depression and other neurological disorders, due to the vulnerability of neurons to stress. This review focuses on functional food nutrients targeting Nrf2 antioxidant pathway and redox resilience genes to regulate the neurosteroid homeostasis and BBB damage associated with altered GABAergic neurotransmission. By exploring the underlying molecular mechanisms using innovative technologies, we aim to develop promising neuroprotective strategies and personalized nutritional and neuroregenerative therapies to prevent or attenuate oxidative stress and neuroinflammation, ultimately promoting brain health.