Microglial NF-κB drives tau spreading and toxicity in a mouse model of tauopathy

Unraveling the potential of neuroinflammation and autophagy in schizophrenia

Schizophrenia (SCZ) is a complex and chronic psychiatric disorder that affects a significant proportion of the global population. Although the precise etiology of SCZ remains uncertain, recent studies have underscored the involvement of neuroinflammation and autophagy in its pathogenesis. Neuroinflammation, characterized by hyperactivated microglia and markedly elevated pro-inflammatory cytokines, has been observed in postmortem brain tissues of SCZ patients and is closely associated with disease severity. Autophagy, a cellular process responsible for eliminating damaged components and maintaining cellular homeostasis, is believed to play a pivotal role in neuronal health and the onset of SCZ. This review explores the roles and underlying mechanisms of neuroinflammation and autophagy in SCZ, with a particular focus on their intricate interplay. Additionally, we provide an overview of potential therapeutic strategies aimed at modulating neuroinflammation and autophagy, including nutritional interventions, anti-inflammatory drugs, antipsychotics, and plant-derived natural compounds. The review also addresses the dual effects of antipsychotics on autophagy. Our objective is to translate these insights into clinical practice, expanding the therapeutic options available to improve the overall health and well-being of individuals with SCZ.

pS396/pS404 (PHF1) tau vaccine outperforms pS199/pS202 (AT8) in rTg4510 tauopathy model

Tauopathies, including Alzheimer's disease (AD) and Frontotemporal Dementia (FTD), are histopathologically defined by the aggregation of hyperphosphorylated pathological tau (pTau) as neurofibrillary tangles in the brain. Site-specific phosphorylation of tau occurs early in the disease process and correlates with progressive cognitive decline, thus serving as targetable pathological epitopes for immunotherapy development. Previously, we developed a vaccine (Qβ-pT181) displaying phosphorylated Thr181 tau peptides on the surface of a Qβ bacteriophage virus-like particle (VLP) that induced robust antibody responses, cleared pathological tau, and rescued memory deficits in a transgenic mouse model of tauopathy. Here we report the characterization and comparison of two additional Qβ VLP-based vaccines targeting the dual phosphorylation sites Ser199/Ser202 (Qβ-AT8) and Ser396/Ser404 (Qβ-PHF1). Both Qβ-AT8 and Qβ-PHF1 vaccines elicited high-titer antibody responses against their pTau epitopes. However, only Qβ-PHF1 rescued cognitive deficits, reduced soluble and insoluble pathological tau, and inflammatory microgliosis in a 4.5-month rTg4510 model of FTD. Both sera from Qβ-AT8 and Qβ-PHF1 vaccinated mice were specifically reactive to tau pathology in human AD post-mortem brain sections. These studies further support the use of VLP-based immunotherapies to target pTau in AD and related tauopathies and provide potential insight into the clinical efficacy of various pTau epitopes in the development of immunotherapies.

Cellular and molecular mechanisms of pathological tau phosphorylation in traumatic brain injury: implications for chronic traumatic encephalopathy

Tau protein plays a critical role in the physiological functioning of the central nervous system by providing structural integrity to the cytoskeletal architecture of neurons and glia through microtubule assembly and stabilization. Under certain pathological conditions, tau is aberrantly phosphorylated and aggregates into neurotoxic fibrillary tangles. The aggregation and cell-to-cell propagation of pathological tau leads to the progressive deterioration of the nervous system. The clinical entity of traumatic brain injury (TBI) ranges from mild to severe and can promote tau aggregation by inducing cellular mechanisms and signalling pathways that increase tau phosphorylation and aggregation. Chronic traumatic encephalopathy (CTE), which is a consequence of repetitive TBI, is a unique tauopathy characterized by pathological tau aggregates located at the depths of the sulci and surrounding blood vessels. The mechanisms leading to increased tau phosphorylation and aggregation in CTE remain to be fully defined but are likely the result of the primary and secondary injury sequelae associated with TBI. The primary injury includes physical and mechanical damage resulting from the head impact and accompanying forces that cause blood-brain barrier disruption and axonal shearing, which primes the central nervous system to be more vulnerable to the subsequent secondary injury mechanisms. A complex interplay of neuroinflammation, oxidative stress, excitotoxicity, and mitochondrial dysfunction activate kinase and cell death pathways, increasing tau phosphorylation, aggregation and neurodegeneration. In this review, we explore the most recent insights into the mechanisms of tau phosphorylation associated with TBI and propose how multiple cellular pathways converge on tau phosphorylation, which may contribute to CTE progression.

Using Single-Cell RNA sequencing with Drosophila, Zebrafish, and mouse models for studying Alzheimer's and Parkinson's disease

Alzheimer's and Parkinson's disease are the most common neurodegenerative diseases, significantly affecting the elderly with no current cure available. With the rapidly aging global population, advancing research on these diseases becomes increasingly critical. Both disorders are often studied using model organisms, which enable researchers to investigate disease phenotypes and their underlying molecular mechanisms. In this review, we critically discuss the strengths and limitations of using Drosophila, zebrafish, and mice as models for Alzheimer's and Parkinson's research. A focus is the application of single-cell RNA sequencing, which has revolutionized the field by providing novel insights into the cellular and transcriptomic landscapes characterizing these diseases. We assess how combining animal disease modeling with high-throughput sequencing and computational approaches has advanced the field of Alzheimer's and Parkinson's disease research. Thereby, we highlight the importance of integrative multidisciplinary approaches to further our understanding of disease mechanisms and thus accelerating the development of successful therapeutic interventions.

Diverse influences on tau aggregation and implications for disease progression

Tau is an intrinsically disordered protein that accumulates in fibrillar aggregates in neurodegenerative diseases. The misfolding of tau can be understood as an equilibrium between different states and their propensity to form higher-order fibers, which is affected by several factors. First, modulation of the biochemical state of tau due to ionic conditions, post-translational modifications, cofactors, and interacting molecules or assemblies can affect the formation and structure of tau fibrils. Second, cellular processes impact tau aggregation through modulating stability, clearance, disaggregation, and transport. Third, through interactions with glial cells, the neuronal microenvironment can affect intraneuronal conditions with impacts on tau fibrilization and toxicity. Importantly, tau fibrils propagate through the brain via a "prion-like" manner, contributing to disease progression. This review highlights the biochemical and cellular pathways that modulate tau aggregation and discusses implications for pathobiology and tau-directed therapeutic approaches.

Endothelial TDP-43 depletion disrupts core blood-brain barrier pathways in neurodegeneration

Endothelial cells (ECs) help maintain the blood-brain barrier but deteriorate in many neurodegenerative disorders. Here we show, using a specialized method to isolate EC and microglial nuclei from postmortem human cortex (92 donors, 50 male and 42 female, aged 20-98 years), that intranuclear cellular indexing of transcriptomes and epitopes enables simultaneous profiling of nuclear proteins and RNA transcripts at a single-nucleus resolution. We identify a disease-associated subset of capillary ECs in Alzheimer's disease, amyotrophic lateral sclerosis and frontotemporal degeneration. These capillaries exhibit reduced nuclear β-catenin and β-catenin-downstream genes, along with elevated TNF/NF-κB markers. Notably, these transcriptional changes correlate with the loss of nuclear TDP-43, an RNA-binding protein also depleted in neuronal nuclei. TDP-43 disruption in human and mouse ECs replicates these alterations, suggesting that TDP-43 deficiency in ECs is an important factor contributing to blood-brain barrier breakdown in neurodegenerative diseases.

Ultrasound-Assisted H2 Transmitter Enables Hydrogen-Gene Therapy to Prevent Anesthesia/Surgery-Induced Cognitive Impairment

Postoperative cognitive dysfunction (POCD) frequently occurs after surgery, resulting in extended hospitalizations, higher healthcare expenses, and potential long-term cognitive impairment. Despite its significant impact, effective preventive and therapeutic strategies for POCD are still lacking. Neuroinflammation plays a crucial role in the pathogenesis of POCD. To address this, a H2 emitter is developed that employs hydrogen-gene therapy facilitated by ultrasound, allowing for the repair of the neuroinflammatory microenvironment in a spatiotemporally controllable manner to effectively prevent anesthesia/surgery-induced cognitive impairment. Utilizing focused ultrasound, the blood-brain barrier can be opened in a controlled manner, enabling the efficient delivery of hydrogen emitters (HPPS) carrying siRNA to the site of neuroinflammation. On one hand, the hydrogen emitter effectively generates hydrogen to eliminate excess hydroxyl radicals; on the other hand, it utilizes siRNA to target and reduce tau protein phosphorylation. This targeted hydrogen-gene therapy strategy has been demonstrated in both mouse and rat postoperative models to significantly reduce neuroinflammation and improve postoperative spatial memory as well as object recognition. This study introduces a novel and effective strategy for preventing anesthesia/surgery-induced cognitive impairment and offering new insights for the treatment of other neuroinflammatory diseases.

Multi-Target Inhibitor of ZJQ- 3 F Against AChE/BACE1/GSK3β Targets Improves the Cognitive Impairment of APP/PS1/Tau Triple-Transgenic Mouse Models of Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is a multifactorial neuropathology characterized by the accumulation of amyloid-beta (Aβ) plaques, neurofibrillary tangles (NFTs) and cholinergic system dysfunction. At present, there is no effective treatment strategy for AD. Our previous research showed that ZJQ-3F acts as an inhibitor of AChE/BACE1/GSK3β, and showed good blood-brain barrier permeability, appropriate bioavailability and oral safety. In order to further study, the protective effect of ZJQ-3F on APP/PS1/Tau transgenic mice was determined.

METHODS

APP/PS1/Tau transgenic mice model of AD was treated with ZJQ-3F from the age of 8 to 12 months, and then behavioral tests was conducted. Western blot, immunohistochemistry and immunofluorescence staining were used to evaluate the level of tau protein, Aβ plaques and synaptic function.

RESULTS

Our results revealed that administration of ZJQ-3F could improve the cognitive function of APP/PS1/Tau transgenic mice. In addition, compared with APP/PS1/Tau mice, the protein expression levels of tau protein phosphorylation site at Ser396, Thr212 and Thr181 in the cortex and hippocampus of ZJQ-3F treated mice was significantly decreased. Moreover, the results showed that ZJQ-3F significantly reduced the deposition of Aβ in the cortex and hippocampus. Furthermore, the results indicated that the protein expression levels of PSD95, SYP and SYT in the cortex and hippocampus were increased markedly after ZJQ-3F was given.

CONCLUSIONS

Our studies suggest that the chronic administration of ZJQ-3F can improve learning and memory ability, reduce tau protein phosphorylation, reduce Aβ deposition and improve synaptic dysfunction in APP/PS1/Tau transgenic model of AD, indicating that ZJQ-3F can be used as a multi-target inhibitor to slow down the progress of AD.

Suppression of NF-κB/NLRP3 by nanoligomer therapy mitigates ethanol and advanced age-related neuroinflammation

Binge alcohol use is increasing among aged adults (>65 yr). Alcohol-related toxicity in aged adults is associated with neurodegeneration; yet, the molecular underpinnings of this age-related sensitivity to alcohol are not well described. Studies utilizing rodent models of neurodegenerative disease reveal heightened activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Nod-like receptor 3 (NLRP3) mediate microglia activation and associated neuronal injury. Our group, and others, have implicated hippocampal-resident microglia as key producers of inflammatory mediators; yet, the link between inflammation and neurodegeneration has not been established in models of binge ethanol exposure and advanced age. Here, we report binge ethanol increased the proportion of NLRP3+ microglia in the hippocampus of aged (18 to 20 mo) female C57BL/6N mice compared with young (3 to 4 mo). In primary microglia, ethanol-induced expression of reactivity markers and NLRP3 inflammasome activation were more pronounced in microglia from aged mice compared with young. Using a NLRP3-specific inhibitor (OLT1177) and a novel brain-penetrant Nanoligomer that inhibits NF-κB and NLRP3 translation (SB_NI_112), we find ethanol-induced microglial reactivity can be attenuated by OLT1177 and SB_NI_112 in microglia from aged mice. In a model of intermittent binge ethanol exposure, SB_NI_112 prevented ethanol-mediated microglia reactivity, IL-1β production, and tau hyperphosphorylation in the hippocampus of aged mice. These data suggest early indicators of neurodegeneration occurring with advanced age and binge ethanol exposure are driven by NF-κB and NLRP3. Further investigation is warranted to explore the use of targeted immunosuppression via Nanoligomers to attenuate neuroinflammation after alcohol consumption in the aging populations.

Unravelling the role of protein kinase R (PKR) in neurodegenerative disease: a review

Protein Kinase R is an essential regulator of many cell activities and belongs to one of the largest and most functionally complex gene families. These are found all over the body, and by adding phosphate groups to the substrate proteins, they regulate their activity and coordinate the action of almost all cellular processes. Recent research has illuminated the involvement of PKR in the pathogenesis of neurodegenerative disorders (NDs), thereby expanding our understanding of intricate molecular mechanisms underlying disease progression. Through their inhibition or activation, they hold potential therapeutic targets for the pathogenesis or protection of NDs. In the case of AD (AD), PKR contributes to the protection or elevation of Aβ accumulation, neuroinflammation, synaptic plasticity alterations, and neuronal excitability. Similarly, in Parkinson's disease (PD), PKR again has a dual role in dopaminergic neuronal loss, gene mutations, and mitochondrial dysfunction via various pathways. Notably, neuronal excitotoxicity, as well as genetic mutations, have been linked to ALS. In Huntington's disease (HD), PKR is associated with decreased or increased mutated genes, striatal neuron degeneration, neuroinflammation, and excitotoxicity. This review emphasizes strategies that target PKR for the treatment of neurodegenerative disorders. Doing so offers valuable insights that can guide future research endeavors and the development of innovative therapeutic approaches.

Novel peptidomimetic compounds attenuate hypoxic-ischemic brain injury in neonatal rats

Hypoxic-ischemic (HI) brain injury is a common neurological problem in neonates. The postsynaptic density protein-95 (PSD-95) is an excitatory synaptic scaffolding protein that regulates synaptic function, and represents a potential therapeutic target to attenuate HI brain injury. Syn3 and d-Syn3 are novel high affinity cyclic peptides that bind the PDZ3 domain of PSD-95. We investigated the neuroprotective efficacy of Syn3 and d-Syn3 after exposure to HI in neonatal rodents. Postnatal (P) day-7 rats were treated with Syn3 and d-Syn3 at zero, 24, and 48-h after carotid artery ligation and 90-min of 8 % oxygen. Hemispheric volume atrophy and Iba-1 positive microglia were quantified by cresyl violet and immunohistochemical staining. Treatment with Syn3 and d-Syn3 reduced tissue volume loss by 47.0 % and 41.0 % in the male plus female, and by 42.1 % and 65.0 % in the male groups, respectively. Syn3 reduced tissue loss by 52.3 % in females. D-Syn3 reduced Iba-1 positive microglia/DAPI ratios in the pooled group, males, and females. Syn3 effects were observed in the pooled group and females. Changes in Iba-1 positive microglia/DAPI cellular ratios correlated directly with reduced hemispheric volume loss, suggesting that Syn3 and d-Syn3 provide neuroprotection in part by their effects on Iba-1 positive microglia. The pathogenic cis phosphorylated Thr231 in Tau (cis P-tau) is a marker of neuronal injury. Cis P-tau was induced in cortical cells of the placebo-treated pooled group, males and females after HI, and reduced by treatment with d-Syn3. Therefore, treatment with these peptidomimetic agents exert neuroprotective effects after exposure of neonatal subjects to HI related brain injury.

Exploring the mechanism by which Zexie Tang regulates Alzheimer's disease: Insights from multi-omics analysis

BACKGROUND

Neurodegenerative disorders, such as Alzheimer's disease (AD), are characterized by a progressive decline in cognitive function. Modulating microglial metabolic reprogramming presents a promising therapeutic avenue for AD. Previous studies have shown that Zexie Tang (ZXT) possesses neuroprotective properties and can ameliorate cognitive impairment, but the underlying mechanisms remain unclear.

PURPOSE

This study aimed to investigate the efficacy of ZXT in improving cognitive function in AD mice using a multi-omics approach and to explore its potential role in modulating microglial metabolic reprogramming.

METHODS

Behavioral assessments were conducted to evaluate the effects of ZXT on cognitive function in APP/PS1 mice. H&E, Nissl, and Thioflavin S staining were performed to assess the impact of ZXT on brain pathology. A multi-omics approach, including transcriptomics, gut microbiota analysis, and metabolomics, was employed to elucidate the mechanisms of action of ZXT. RT-qPCR, immunoblotting, and immunofluorescence were used to validate the effects of ZXT on glycolipid metabolism, neuroinflammation, and the AMPK-mTOR-HIF1α pathway.

RESULTS

ZXT effectively protected against cognitive deficits, reduced hippocampal neuronal apoptosis, and decreased Aβ plaque deposition. Transcriptomics analysis revealed that ZXT was involved in immune system processes and metabolic processes and had a specific cellular response with microglia. Additionally, ZXT regulated the composition and functions of brain metabolites and gut microbiota. Our study demonstrated that ZXT positively influenced glucolipid metabolism and attenuated neuroinflammation, which were linked to the AMPK-mTOR-HIF1α pathway in the brain.

CONCLUSION

Our findings suggested that ZXT may mitigate cognitive deficits in APP/PS1 mice by modulating gut microbiota and enhancing brain energy metabolism. ZXT regulated glucolipid metabolism and neuroinflammation by modulating microglial metabolic reprogramming involving the AMPK-mTOR-HIF1α pathway.

Activation of Nuclear Factor-kappa B in the nucleus accumbens core is necessary for chronic stress-induced glutamate and neuro-immune alterations that facilitate cocaine self-administration

Stressful events are associated with impaired glutamate signaling and neuroimmune adaptations that may increase the vulnerability of individuals to cocaine addiction. We previously demonstrated that chronic stress induced reactive microglia and increased TNF-α expression in the nucleus accumbens core (NAcore), both alterations strongly linked with impaired glutamate homeostasis and the facilitation of cocaine self-administration. The nuclear factor kappa-B (NF-κB) is a critical regulator of many immune- and addiction-related genes, such as the gene coding for glutamate transporter (GLT-1), and it is considered a master regulator of inflammation, reported to be a key driver of microglia activation in psychiatric diseases. However, no studies have examined the role of NF-κB signaling within the NAcore in the neuroimmune and glutamate mechanism, underpinning stress-induced vulnerability to cocaine self-administration. Here we investigate whether viral dominant negative inhibition of I kappa B kinase (IKKdn), a signaling molecule responsible for NF-κB activation, would prevent stress-induced facilitation to cocaine self-administration and associated changes in accumbal GLT-1 and TNF-α expression. We also explore N-myc proto-oncogene protein (N-myc) levels as a link between NF-κB and stress-induced GLT-1 downregulation. For seven days (days 1-7), adult male rats were restrained for 2 h/day. Animals were administered an intra-NAcore with IKKdn or empty lentiviruses on day 14 after the first restraint stress session. Marked activation of NF-κB was detected in the NAcore of stressed subjects, along with increased NF-κB expression in astrocytes. Consistently, viral NF-κB inhibition prevented stress-induced facilitation of cocaine self-administration. Moreover, NF-κB blockade results in the restoration of stress-induced reduction in GLT-1 levels and was effective in suppressing stress-induced TNF-α within the NAcore. These findings suggest that accumbal NF-κB signaling exerts a central control over stress-altered downstream neuroimmune and glutamate function underlying vulnerability to cocaine use disorders.

Acridine Benzimidazolium Derivatives Induced Protective Microglia Polarization and In Silico TDP-43 Interaction─Potential Implications for Amyotrophic Lateral Sclerosis

Abnormal protein aggregation and associated neuronal-glial cell cytotoxicity lead to a plethora of neurodegenerative disorders. Most of the earlier investigations on understanding neurodegenerative disease progression and cure focused on neuronal damage and restoration potential. With increased evidence on the role of glial cells like microglia and astrocytes in mediating these disorders, more studies are dedicated to understanding the role of inflammatory responses mediated by glial cells and how they lead to neuroinflammation. Amyotrophic lateral sclerosis (ALS) is a late-onset neurodegenerative disorder caused by TDP-43 aggregation that affects motor neurons. Pro-inflammatory microglia are considered to aggravate the disorder condition. In the current study, a previously reported molecule with TDP-43 inhibition, 3,3'-(acridine-4,5-diylbis(methylene))bis(1-(carboxymethyl)imidazol-3-ium) dibromide salt (AIM4), is analyzed for its microglia polarization properties along with two other derivatives, 3,3'-(acridine-4,5-diylbis(methylene))bis(1-(2-ethoxy-2-oxoethyl)benzimidazol-3-ium) dibromide salt (ABE) and 3,3'-(acridine-4,5-diylbis(methylene))bis(1-(carboxymethyl)benzoimidazol-3-ium) dibromide salt (ABA). The 3,3'-(acridine-4,5-diylbis(methylene))bis(1-(2-ethoxy-2-oxoethyl)benzimidazol-3-ium) dibromide salt (ABE) and 3,3'-(acridine-4,5-diylbis(methylene))bis(1-(carboxymethyl) benzimidazol-3-ium) dibromide salt (ABA) display the increased ability to maintain microglial cells to anti-inflammatory state and TDP-43 binding as compared to 3,3'-(acridine-4,5-diylbis(methylene)) bis(carboxymethyl)imidazolium dibromide salt (AIM4). This was confirmed from total nitrite levels, mitochondria membrane potential analysis, and molecular docking studies. The selected pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) displayed decreased levels, and anti-inflammatory cytokines IL-4 and IL-10 displayed increased levels, however not very significantly, upon treatment with all acridine derivatives. The compounds were investigated on lipopolysaccharides (LPS)-triggered mouse microglial cells and Danio rerio embryos displaying no significant cytotoxicity and physiological changes (cardiac rhythm), respectively. In molecular docking studies, alanine at 315 mutated to glutamate of TDP-43 directly interacts with AIM4. However, π-σ interactions of the aromatic backbone of acridine in ABE and ABA with 313 phenylalanine of TDP-43 along with hydrogen bonds formed between 309, 310 glycine amino acids and imidazolium bromide side chains rendered a stronger binding of these acridine derivatives with the protein potentially inhibiting fibrillation. Conclusion: ABA, ABE, and AIM4 maintain microglia in an anti-inflammatory state. However, more studies are required to understand its interaction with TDP-43 and the mechanism of its anti-inflammatory nature.

Do microglia metabolize fructose in Alzheimer's disease?

Alzheimer's disease (AD) is an age-associated neurodegenerative disorder with a complex etiology. While emerging AD therapeutics can slow cognitive decline, they may worsen dementia in certain groups of individuals. Therefore, alternative treatments are much needed. Microglia, the brain resident macrophages, have the potential to be novel therapeutic targets as they regulate many facets of AD, including lipid droplet (LD) accumulation, amyloid beta (Aβ) clearance, and neuroinflammation. To carry out such functions, microglia undergo phenotypic changes, which are linked to shifts in metabolism and substrate utilization. While homeostatic microglia are driven by oxidative phosphorylation (OXPHOS) and glycolysis, in aging and AD, microglia shift further towards glycolysis. Interestingly, this "metabolic reprogramming" may be linked to an increase in fructose metabolism. In the brain, microglia predominantly express the fructose transporter SLC2A5 (GLUT5), and enzymes involved in fructolysis and endogenous fructose production, with their expression being upregulated in aging and disease. Here, we review evidence for fructose uptake, breakdown, and production in microglia. We also evaluate emerging literature targeting fructose metabolism in the brain and periphery to assess its ability to modulate microglial function in AD. The ability of microglia to transport and utilize fructose, coupled with the well-established role of fructose in metabolic dysfunction, supports the notion that microglial fructose metabolism may be a novel potential therapeutic target for AD.

Microglial Annexin A3 Downregulation Alleviates Ischemic Injury by Inhibiting NF-κB/NLRP3-mediated Inflammation

Microglial inflammation is a hallmark of ischemic stroke. Annexin A3 (ANXA3) is expressed in microglia and plays a detrimental role in stroke. However, the role of ANXA3 in microglial inflammation after ischemic stroke is unclear. In this study, an ischemic stroke model was established in mice via middle cerebral artery occlusion (MCAO). The adeno-associated virus shANXA3 (AAV-shANXA3) was injected into ipsilateral cortex ischemic lesion, and the infarction volume, neurological score, and neuronal injury were examined. Moreover, primary microglia were transfected with a lentivirus (LV-shANXA3) and subjected to oxygen-glucose deprivation (OGD). Neuron viability and lactose dehydrogenase (LDH) levels of neurons cocultured with microglia were analyzed. Additionally, microglial activation and ANXA3, p-NF-κB, NLRP3 and downstream proteins of NLRP3 inflammasome (cleaved caspase-1, N-GSDMD and IL-1β) expression levels were measured. We found that microglial ANXA3 expression was increased after ischemic injury and that ANXA3 knockdown reduced the infarction volume, mitigated neurological deficits, and alleviated neuronal injuries. Additionally, ANXA3 knockdown ameliorated microglial activation and reduced the levels of p-NF-κB and inhibited NLRP3 inflammasome signaling. Furthermore, ANXA3 upregulation resulted in decreased IκBα levels, whereas ANXA3 downregulation resulted in increased IκBα levels. Notably, IκBα knockdown blocked the neuroprotective effects of AAV-shANXA3 against ischemic injury. In conclusion, microglial ANXA3 downregulation alleviates ischemic stroke by inhibiting NF-κB/NLRP3-mediated microglial inflammation, which indicates that ANXA3 may be a potential therapeutic target for ischemic stroke.

Pathological tau activates inflammatory nuclear factor-kappa B (NF-κB) and pT181-Qβ vaccine attenuates NF-κB in PS19 tauopathy mice

Tau regulates neuronal integrity. In tauopathy, phosphorylated tau detaches from microtubules and aggregates, and is released into the extracellular space. Microglia are the first responders to the extracellular tau, a danger/damage-associated molecular pattern (DAMP), which can be cleared by proteostasis and activate innate immune response gene expression by nuclear factor-kappa B (NF-κB). However, longitudinal NF-κB activation in tauopathies and whether pathological tau (pTau) contributes to NF-κB activity is unknown. Here, we tau oligomers from human Alzheimer's disease brain (AD-TO) activate NF-κB in mouse microglia and macrophages reducing the IκBα via promoting its secretion in the extracellular space. NF-κB activity peaks at 9- and 11-months age in PS19Luc + and hTauLuc + mice, respectively. Reducing pTau via pharmacological (DOX), genetic ( Mapt -/- ) or antibody-mediated neutralization (immunization with pT181-Qβ vaccine) reduces NF-κB activity, and together suggest pTau is a driver of NF-κB and chronic neuroinflammation tauopathies.

Summary

Neuronal tau activates microglial NF-κB constitutively by secreting its inhibitor IκBα. NF-κB activation in PS19Luc + and hTauLuc + mice peaks at 9- and 11-months of age, respectively. Neutralizing pTau with pT181-Qβ vaccine (targeting phosphorylated threonine 181 tau) alleviates NF-κB activity in tauopathy mice.

Role of Tau Protein Hyperphosphorylation in Diabetic Retinal Neurodegeneration

Diabetic retinal neurodegeneration (DRN) is an early manifestation of diabetic retinopathy (DR) characterized by neurodegeneration that precedes microvascular abnormalities in the retina. DRN is characterized by apoptosis of retinal ganglion cells (involves alterations in retinal ganglion cells [RGCs], photoreceptors, amacrine cells and bipolar cells and so on), reactive gliosis, and reduced retinal neuronal function. Tau, a microtubule-associated protein, is a key mediator of neurotoxicity in neurodegenerative diseases, with functions in phosphorylation-dependent microtubule assembly and stabilization, axonal transport, and neurite outgrowth. The hyperphosphorylated tau (p-tau) loses its ability to bind to microtubules and aggregates to form paired helical filaments (PHFs), which further form neurofibrillary tangles (NFTs), leading to abnormal cell scaffolding and cell death. Studies have shown that p-tau can cause degeneration of RGCs in DR, making tau pathology a new pathophysiological model for DR. Here, we review the mechanisms by which p-tau contribute to DRN, including insulin resistance or lack of insulin, mitochondrial damage such as mitophagy impairment, mitochondrial axonal transport defects, mitochondrial bioenergetics dysfunction, and impaired mitochondrial dynamics, Abeta toxicity, and inflammation. Therefore, this article proposes that tau protein hyperphosphorylation plays a crucial role in the pathogenesis of DRN and may serve as a novel therapeutic target for combating DRN.

Porphyromonas gingivalis outer membrane vesicles alter cortical neurons and Tau phosphorylation in the embryonic mouse brain

Porphyromonas gingivalis (Pg) is an oral bacterial pathogen that has been associated with systemic inflammation and adverse pregnancy outcomes such as low birth weight and pre-term birth. Pg drives these sequelae through virulence factors decorating the outer membrane that are present on non-replicative outer membrane vesicles (OMV) that are suspected to be transmitted systemically. Given that Pg abundance can increase during pregnancy, it is not well known whether Pg-OMV can have deleterious effects on the brain of the developing fetus. We tested this possibility by treating pregnant C57/Bl6 mice with PBS (control) and OMV from ATCC 33277 by tail vein injection every other day from gestational age 3 to 17. At gestational age 18.5, we measured dam and pup weights and collected pup brains to quantify changes in inflammation, cortical neuron density, and Tau phosphorylated at Thr231. Dam and pup weights were not altered by Pg-OMV exposure, but pup brain weight was significantly decreased in the Pg-OMV treatment group. We found a significant increase of Iba-1, indicative of microglia activation, although the overall levels of IL-1β, IL-6, TNFα, IL-4, IL-10, and TGFβ mRNA transcripts were not different between the treatment groups. Differences in IL-1β, IL-6, and TNFα concentrations by ELISA showed IL-6 was significantly lower in Pg-OMV brains. Cortical neuron density was modified by treatment with Pg-OMV as immunofluorescence showed significant decreases in Cux1 and SatB2. Overall p-Tau Thr231 was increased in the brains of pups whose mothers were exposed to Pg-OMV. Together these results demonstrate that Pg-OMV can significantly modify the embryonic brain and suggests that Pg may impact offspring development via multiple mechanisms.

Microglial reprogramming enhances antitumor immunity and immunotherapy response in melanoma brain metastases

Melanoma is one of the tumor types with the highest risk of brain metastasis. However, the biology of melanoma brain metastasis and the role of the brain immune microenvironment in treatment responses are not yet fully understood. Using preclinical models and single-cell transcriptomics, we have identified a mechanism that enhances antitumor immunity in melanoma brain metastasis. We show that activation of the Rela/Nuclear Factor κB (NF-κB) pathway in microglia promotes melanoma brain metastasis. Targeting this pathway elicits microglia reprogramming toward a proinflammatory phenotype, which enhances antitumor immunity and reduces brain metastatic burden. Furthermore, we found that proinflammatory microglial markers in melanoma brain metastasis are associated with improved responses to immune checkpoint inhibitors in patients and targeting Rela/NF-κB pathway in mice improves responses to these therapies in the brain, suggesting a strategy to enhance antitumor immunity and responses to immune checkpoint inhibitors in patients with melanoma brain metastasis.

The acetyltransferase GCN5 contributes to neuroinflammation in mice by acetylating and activating the NF-κB subunit p65 in microglia

Neuroinflammation promotes the progression of various neurological and neurodegenerative diseases. Disrupted homeostasis of protein acetylation is implicated in neurodegeneration, and the lysine acetyltransferase GCN5 (also known as KAT2A) is implicated in peripheral inflammation. Here, we investigated whether GCN5 plays a role in neuroinflammation in the brain. Systemic administration of the bacterial molecule LPS in mice to induce peripheral inflammation increased the abundance of GCN5 in various organs, including in the brain and specifically in microglia. In response to LPS, GCN5 mediated the induction of the proinflammatory cytokines TNF-α and IL-6 and the inflammatory mediators COX-2 and iNOS in microglia. Further investigation in cultured microglial cells revealed that GCN5 was activated downstream of the innate immune receptor TLR4 to acetylate Lys310 in the NF-κB subunit p65, thereby enabling the nuclear translocation and transcriptional activity of NF-κB and the resulting inflammatory response. Thus, targeting GCN5 might be explored further as a strategy to reduce neuroinflammation in the treatment of associated diseases.

Pro-resolving lipid mediator reduces amyloid-β42-induced gene expression in human monocyte-derived microglia

JOURNAL/nrgr/04.03/01300535-202503000-00031/figure1/v/2024-06-17T092413Z/r/image-tiff Specialized pro-resolving lipid mediators including maresin 1 mediate resolution but the levels of these are reduced in Alzheimer's disease brain, suggesting that they constitute a novel target for the treatment of Alzheimer's disease to prevent/stop inflammation and combat disease pathology. Therefore, it is important to clarify whether they counteract the expression of genes and proteins induced by amyloid-β. With this objective, we analyzed the relevance of human monocyte-derived microglia for in vitro modeling of neuroinflammation and its resolution in the context of Alzheimer's disease and investigated the pro-resolving bioactivity of maresin 1 on amyloid-β42-induced Alzheimer's disease-like inflammation. Analysis of RNA-sequencing data and secreted proteins in supernatants from the monocyte-derived microglia showed that the monocyte-derived microglia resembled Alzheimer's disease-like neuroinflammation in human brain microglia after incubation with amyloid-β42. Maresin 1 restored homeostasis by down-regulating inflammatory pathway related gene expression induced by amyloid-β42 in monocyte-derived microglia, protection of maresin 1 against the effects of amyloid-β42 is mediated by a re-balancing of inflammatory transcriptional networks in which modulation of gene transcription in the nuclear factor-kappa B pathway plays a major part. We pinpointed molecular targets that are associated with both neuroinflammation in Alzheimer's disease and therapeutic targets by maresin 1. In conclusion, monocyte-derived microglia represent a relevant in vitro microglial model for studies on Alzheimer's disease-like inflammation and drug response for individual patients. Maresin 1 ameliorates amyloid-β42-induced changes in several genes of importance in Alzheimer's disease, highlighting its potential as a therapeutic target for Alzheimer's disease.

Exposure to Manganese Induces Autophagy-Lysosomal Pathway Dysfunction-Mediated Tauopathy by Activating the cGAS-STING Pathway in the Brain

Manganese (Mn) exposure leads to pathological accumulation of Tau-associated neurodegenerative disease and has become a major public health concern. However, the precise mechanism underlying this effect remains unclear. Here, the mechanism by which Mn induces dysfunction of autophagy-lysosomal pathway-mediated tauopathy by activating the cGAS-STING pathway was explored both in vitro and in vivo. Mn exposure induced tauopathy in microglia and in mice while activating the cGAS-STING pathway, inducing type I interferon production, and impairing the degradation function of the autophagy-lysosomal pathway. Importantly, inactivation of the cGAS-STING pathway rescued the degradation activity of the autophagy-lysosomal pathway, while tauopathy was markedly attenuated, as shown in both cGAS-knockout and STING-knockout BV2 microglia and in mice. Moreover, the autophagy inhibitor 3-methyladenine (3-MA) restored the impaired degradation activity of the autophagy-lysosomal pathway by inactivating the cGAS-STING pathway, thereby clearing Tau aggregation. Taken together, these results indicate that Mn exposure induces tauopathy by impairing the function of the autophagy-lysosomal pathway through the activation of the cGAS-STING pathway. Thus, this study identifies a novel mechanism by which Mn exposure induces Tau aggregation, which in turn triggers potential neurotoxicity, providing a foundation for future drug target research.

IFNγ preconditioning improves neuroprotection of MSC-derived vesicles on injured retinal ganglion cells by suppressing microglia activation via miRNA-dependent ribosome activity

Aim: Microglial activation plays a pivotal role in the pathogenesis of retinal ganglion cell (RGC) degeneration resulting from optic nerve crush (ONC). Small extracellular vesicles (sEVs) secreted by mesenchymal stem cells (MSCs) have the potential to prevent retinal degeneration by modulating microglial activation. In this study, we elucidated the specific effects of sEVs derived from IFN-γ-primed MSCs on the phenotypic transition of microglia and the associated pathways in ONC mice. Methods: The ONC mice model was established and administered intravitreal injection with the sEVs derived from native MSCs (native sEVs) and the sEVs derived from MSCs primed with IFN-γ (IFNγ-sEVs). Their respective effects on the survival of the retinal ganglion cells (RGCs) and the transition of microglia phenotypes were determined through visual function testing and immunohistochemical staining. Combined with mRNA seq and microRNA seq techniques, we elucidated the mechanism of modulation of microglia phenotypic transformation by sEVs derived from MSCs primed by IFNγ. Results: It demonstrated that IFNγ-sEVs exhibited superior protective effects against RGC loss and reduced inflammatory responses in the ONC retina compared to native sEVs. Both types of sEVs promoted microglia activation to disease-associated microglia (DAM) phenotype, while IFNγ-sEVs especially suppressed interferon-responsive microglia (IRM) activation during RGCs degeneration. Subsequent miRNA sequencing suggested that miR-423-5p, which exhibited the most significant differential expression between the two sEVs types and elevated expression in IFNγ-sEVs, inhibited the expression of IRM and ribosomal genes. Conclusion: These findings suggest that IFN-γ-preconditioned MSCs may enhance sEVs of neuroprotection on RGCs by suppressing IRM activation through the secretion of sEVs containing specific microRNAs in ONC mice.

OTULIN Interactome Reveals Immune Response and Autophagy Associated with Tauopathy in a Mouse Model

Tauopathies are neurodegenerative diseases that are pathologically characterized by accumulation of misfolded microtubule-associated protein tau aggregates in the brain. Deubiquitination, particularly by OTULIN, a unique deubiquitinase targeting methionine-1 (M1) linkages from linear ubiquitin chain assembly complex (LUBAC)), is reportedly associated with the accumulation of neurotoxic proteins in several neurodegenerative diseases, likely including tauopathies. To investigate the potential roles of OTULIN in tauopathies, we analyzed the OTULIN interactome in hippocampal tissues from PS19 transgenic (Tg) mice and their non-transgenic (nTg) littermate controls using affinity purification-mass spectrometry (AP-MS). We identified 705 and 800 proteins enriched in Tg and nTg samples, respectively, with a protein false discovery rate (FDR) of <1%. Of these, 189 and 205 proteins were classified as probable OTULIN interactors in Tg and nTg groups, respectively, based on Significance Analysis of INTeractome (SAINT) score of ≥0.80 and FDR of ≤ 5%. A total of 84 proteins were identified as OTULIN interactors in the PS19 Tg group, while 100 proteins were associated with OTULIN in the nTg controls. Functional enrichment analyses revealed that OTULIN-interacting proteins in the nTg group were enriched in pathways related to spliceosome, complement and coagulation cascades, and ribosome, whereas those in the Tg group were associated with immune response and autophagy. These findings suggest that OTULIN-interacting proteins may play a critical role in the pathogenesis of tauopathy in this mouse model.

MAIT cell deficiency exacerbates neuroinflammation in P301S human tau transgenic mice

The role of immune cells in neurodegeneration remains incompletely understood. Our recent study revealed the presence of mucosal-associated invariant T (MAIT) cells in the meninges, where they express antioxidant molecules to maintain meningeal barrier integrity. Accumulation of misfolded tau proteins are a hallmark of neurodegenerative diseases. The role of MAIT cells in tau-related neuroinflammation and neurodegeneration, however, remains unclear. Here we report that the meninges of P301 mutant human tau transgenic mice had increased numbers of MAIT cells, which retained their expression of antioxidant molecules. Mr1 -/- P301S mice that lacked MAIT cells exhibited increased tau pathology and hippocampus atrophy compared to control Mr1 +/+ P301S mice. Adoptive transfer of MAIT cells reduced tau pathology and hippocampus atrophy in Mr1 -/- P301S mice. Meningeal barrier integrity was compromised in Mr/ -/- P301S mice, but not in control Mr1 +/+ P301S mice. A distinctive microglia subset with proinflammatory gene expression profile (M-inflammatory) was enriched in the hippocampus of Mr1 -/- P301S mice. The transcriptomes of the remaining microglia in these mice also shifted towards a proinflammatory state, with increased expression of inflammatory cytokines, chemokines, and genes related with ribosome biogenesis and immune responses to toxic substances. The transfer of MAIT cells restored meningeal barrier integrity and suppressed microglial inflammation in the Mr1 -/- P301S mice. Together, our data indicate an important role for MAIT cells in regulating tau-pathology-related neuroinflammation and neurodegeneration.

TMF Attenuates Cognitive Impairment and Neuroinflammation by Inhibiting the MAPK/NF-κB Pathway in Alzheimer's Disease: A Multi-Omics Analysis

The rising prevalence of Alzheimer's disease (AD) underscores the urgent need for novel therapeutic agents derived from natural sources. Among flavonoids, 3',4',5,7-tetramethoxyflavone (TMF), a structural analog of luteolin, has gained attention for its favorable pharmacokinetics and potential neuroprotective properties. Despite the significant neuroprotective effects and favorable pharmacokinetics of TMF, its efficacy and mechanism of action in AD remain unclear. This study explored TMF's pharmacological effects in AD models, highlighting its ability to improve memory and cognitive deficits in APP/PS1 mice. TMF reduced Aβ plaques, NFTs formation, and glial activation while suppressing neuroinflammation through the MAPK/NF-κB pathway. Further analysis in LPS-induced BV2 cells revealed TMF's ability to reduce microglial activation. These findings highlight the anti-neuroinflammatory activity of TMF, suggesting its potential as a treatment for AD.

Mechanisms of comorbidity between Alzheimer's disease and pain

Clinical studies have revealed a significant correlation between pain and neurodegenerative diseases, particularly Alzheimer's disease (AD). However, due to cognitive and speech impairments, AD patients, especially those in moderate to severe stages, are often overlooked in pain management. The challenges in obtaining pain-related information from this population exacerbate the issue. Although recent clinical research has increasingly recognized the comorbidity of AD and pain, the pathological alterations and interactive mechanisms underlying this relationship remain inadequately explored. This review provides a comprehensive analysis of the clinical features and pathological mechanisms of AD with and without pain comorbidity. It examines underlying processes, including neuroinflammation, peripheral-central immune interactions, and neurotransmitter dynamics. Furthermore, it highlights current pain assessment and management strategies in AD patients. By offering a theoretical framework, this review aims to support the development of effective pain management approaches and serve as a reference for clinical interventions targeting AD-associated pain. HIGHLIGHTS: The comorbidity between AD and CP encompasses multiple interrelated biological pathways, such as neurodegeneration and inflammatory responses. The damage to neurons and synapses in AD patients influences the brain regions responsible for processing pain, thereby reducing the pain response. Neuroinflammation plays a vital role in the development of both AD and CP. Enhanced inflammatory responses have an impact on the CNS and promote sensitization. Common neurotransmitter alterations exist in the comorbidity of AD and CP, influencing cognition, emotion, and pain perception.

Alzheimer's disease: insights into pathology, molecular mechanisms, and therapy

Alzheimer's disease (AD), the leading cause of dementia, is characterized by the accumulation of amyloid plaques and neurofibrillary tangles in the brain. This condition casts a significant shadow on global health due to its complex and multifactorial nature. In addition to genetic predispositions, the development of AD is influenced by a myriad of risk factors, including aging, systemic inflammation, chronic health conditions, lifestyle, and environmental exposures. Recent advancements in understanding the complex pathophysiology of AD are paving the way for enhanced diagnostic techniques, improved risk assessment, and potentially effective prevention strategies. These discoveries are crucial in the quest to unravel the complexities of AD, offering a beacon of hope for improved management and treatment options for the millions affected by this debilitating disease.

Identification of therapeutic targets for Alzheimer's Disease Treatment using bioinformatics and machine learning

Alzheimer's disease (AD) is a complex neurodegenerative disorder that currently lacks effective treatment options. This study aimed to identify potential therapeutic targets for the treatment of AD using comprehensive bioinformatics methods and machine learning algorithms. By integrating differential gene expression analysis, weighted gene co-expression network analysis, Mfuzz clustering, single-cell RNA sequencing, and machine learning algorithms including LASSO regression, SVM-RFE, and random forest, five hub genes related to AD, including PLCB1, NDUFAB1, KRAS, ATP2A2, and CALM3 were identified. PLCB1, in particular, exhibited the highest diagnostic value in AD and showed significant correlation with Braak stages and neuronal expression. Furthermore, Noscapine, PX-316, and TAK-901 were selected as potential therapeutic drugs for AD based on PLCB1. This research provides a comprehensive and reliable method for the discovery of AD therapeutic targets and the construction of diagnostic models, offering important insights and directions for future AD treatment strategies and drug development.

Beyond Amyloid and Tau: The Critical Role of Microglia in Alzheimer's Disease Therapeutics

Alzheimer's disease (AD) is traditionally viewed through the lens of the amyloid cascade hypothesis, implicating amyloid-beta and tau protein aggregates as the main pathological culprits. However, burgeoning research points to the brain's resident immune cells, microglia, as critical players in AD pathogenesis, progression, and potential therapeutic interventions. This review examines the dynamic roles of microglia within the intricate framework of AD. We detail the involvement of these immune cells in neuroinflammation, explaining how their activation and response fluctuations may influence the disease trajectory. We further elucidate the complex relationship between microglia and amyloid-beta pathology. This study highlights the dual nature of these cells, which contribute to both aggregation and clearance of the amyloid-beta protein. Moreover, an in-depth analysis of the interplay between microglia and tau unveils the significant, yet often overlooked, impact of this interaction on neurodegeneration in AD. Shifting from the conventional therapeutic approaches, we assess the current AD treatments primarily targeting amyloid and tau and introduce novel strategies that involve manipulating microglial functions. These innovative methods herald a potential paradigm shift in the management of AD. Finally, we explore the burgeoning field of precision diagnosis and the pursuit of robust AD biomarkers. We underline how a more profound comprehension of microglial biology could enrich these essential areas, potentially paving the way for more accurate diagnostic tools and tailored treatment strategies. In conclusion, this review expands on the conventional perspective of AD pathology and treatment, drawing attention to the multifaceted roles of microglia. As we continue to enhance our understanding of these cells, microglial-focused therapeutic interventions emerge as a promising frontier to bolster our arsenal to fight against AD.

APOE Christchurch enhances a disease-associated microglial response to plaque but suppresses response to tau pathology

BACKGROUND

Apolipoprotein E ε4 (APOE4) is the strongest genetic risk factor for late-onset Alzheimer's disease (LOAD). A recent case report identified a rare variant in APOE, APOE3-R136S (Christchurch), proposed to confer resistance to autosomal dominant Alzheimer's Disease (AD). However, it remains unclear whether and how this variant exerts its protective effects.

METHODS

We introduced the R136S variant into mouse Apoe (ApoeCh) and investigated its effect on the development of AD-related pathology using the 5xFAD model of amyloidosis and the PS19 model of tauopathy. We used immunohistochemical and biochemical analysis along with single-cell spatial omics and bulk proteomics to explore the impact of the ApoeCh variant on AD pathological development and the brain's response to plaques and tau.

RESULTS

In 5xFAD mice, ApoeCh enhances a Disease-Associated Microglia (DAM) phenotype in microglia surrounding plaques, and reduces plaque load, dystrophic neurites, and plasma neurofilament light chain. By contrast, in PS19 mice, ApoeCh suppresses the microglial and astrocytic responses to tau-laden neurons and does not reduce tau accumulation or phosphorylation, but partially rescues tau-induced synaptic and myelin loss. We compared how microglia responses differ between the two mouse models to elucidate the distinct DAM signatures induced by ApoeCh. We identified upregulation of antigen presentation-related genes in the DAM response in a PS19 compared to a 5xFAD background, suggesting a differential response to amyloid versus tau pathology that is modulated by the presence of ApoeCh. Bulk proteomics show upregulated mitochondrial protein abundance with ApoeCh in 5xFAD mice, but reductions in mitochondrial and translation associated proteins in PS19 mice.

CONCLUSIONS

These findings highlight the ability of the ApoeCh variant to modulate microglial responses based on the type of pathology, enhancing DAM reactivity in amyloid models and dampening neuroinflammation to promote protection in tau models. This suggests that the Christchurch variant's protective effects likely involve multiple mechanisms, including changes in receptor binding and microglial programming.

Agarwood as a potential therapeutic for Alzheimer's disease: Mechanistic insights and target identification

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and functional impairments. Despite extensive research, its pathogenesis remains incompletely understood, and effective treatments are limited. This study explored the therapeutic potential of agarwood in AD by integrating network pharmacology, protein-protein interaction (PPI) network analysis, and single-cell expression analysis. The results revealed that agarwood compounds may modulate key inflammatory genes such as NFKB1, STAT1, and TLR4, alleviating neuroinflammation; enhance the expression of HSP90 and regulate KDR signaling to improve blood-brain barrier (BBB) integrity; and promote the activity of PTPN11 and CXCR4 to support oligodendrocyte precursor cell (OPC) repair and remyelination. Single-cell expression analysis highlighted cell-type-specific expression patterns, particularly in OPCs and endothelial cells, underscoring their relevance in AD pathology. Agarwood's multi-dimensional therapeutic potential positions it as a promising candidate for the development of novel AD treatments.

Integrating network pharmacology and multi-omics to explore the mechanism of Callicarpa kwangtungensis Chun in ameliorating Alzheimer's disease pathology in APP/PS1 mice

ETHNOPHARMACOLOGICAL RELEVANCE

Callicarpa kwangtungensis Chun (CK) is a traditional herb for the treatment of blood stasis, hemostasis, anti-inflammation, and antidepressant. Previous studies have showen that CK extract has significant anti-neuroinflammatory activity. However, the mechanism by which it treats AD is still unclear.

AIM OF STUDY

This study aimed to investigate the effects and mechanisms of CK in ameliorating AD pathology using in vivo and in vitro models, supported by a multi-omics analysis approach.

MATERIALS AND METHODS

The chemical composition of CK was characterized using UPLC-QE Plus-MS/MS. The effects and mechanisms of CK on AD pathology were then investigated using APP/PS1 mice and BV2 and HT22 cell models, with comprehensive insights provided by network pharmacology, transcriptomics, and metabolomics analyses.

RESULTS

This study is the first to report the identification of 146 compounds from CK. CK administration led to significant improvements in cognitive function, reduced amyloid-beta and neurofibrillary tangle formation, and inhibited the activation of microglia and astrocytes in APP/PS1 mice. Comprehensive analyses suggest that CK may modulate the TCA cycle through the PI3K-AKT signaling pathways and inflammation-related MAPK and NF-κB signaling pathways. In vitro studies revealed that CK significantly inhibited LPS-induced inflammation and oxidative stress in BV2 cells, as well as reduced oxidative stress and neuronal apoptosis in HT22 cells.

CONCLUSION

These findings underscore the potential of CK as a therapeutic agent in alleviating AD pathology. This study offers new insights into CK's mechanisms, suggesting that its therapeutic effects may be achieved through the coordinated reduction of neuroinflammation, oxidative stress, and neuronal apoptosis across multiple pathways, collectively working to counteract AD pathology.

APOE3-R136S mutation confers resilience against tau pathology via cGAS-STING-IFN inhibition

The Christchurch mutation (R136S) on the APOE3 (E3 S/S ) gene is associated with attenuation of tau load and cognitive decline despite the presence of a causal PSEN1 mutation and high levels of amyloid beta pathology in the carrier1. However, the specific molecular mechanisms enabling the E3 S/S mutation to mitigate tau-induced neurodegeneration remain unclear. Here, we replaced mouse ApoE with wild-type human E3 or E3 S/S on a tauopathy background. The R136S mutation markedly decreased tau load and protected against tau-induced synaptic loss, myelin loss, and reduction in theta and gamma powers. Additionally, the R136S mutation reduced interferon response to tau pathology in both mouse and human microglia, suppressing cGAS-STING activation. Treating tauopathy mice carrying wild-type E3 with a cGAS inhibitor protected against tau-induced synaptic loss and induced similar transcriptomic alterations to those induced by the R136S mutation across brain cell types. Thus, suppression of microglial cGAS-STING-IFN pathway plays a central role in mediating the protective effects of R136S against tauopathy.

Exploring the link between dystrophic microglia and the spread of Alzheimer's neuropathology

Genetics and other data modalities indicate that microglia play a critical role in Alzheimer's disease progression, but details of the disease-driving influence of microglia are poorly understood. Microglial cells can be parsed into subtypes based on their histological appearance. One subtype of microglia, termed dystrophic microglia, is characterized structurally by fragmented processes and cytoplasmic decay, and their presence has been associated with ageing and neurodegeneration. Recent studies suggest that the interaction between tau proteins and amyloid-β might induce dystrophic changes in microglia, potentially linking amyloid-β and tau pathologies to their effects on these microglia. We developed a study of human brains to test the hypothesis that dystrophic microglia are involved in Alzheimer's disease progression. We speculated that if their presence is unique to Alzheimer's disease neuropathological change, they would be substantially more common in Alzheimer's disease neuropathological change than in neurodegenerative diseases characterized by other proteinopathies, e.g. α-synuclein or transactive response (TAR) DNA-binding protein 43 kDa (TDP-43) pathology. Our analyses used histologically stained sections from five human brain regions of 64 individuals across six disease states, from healthy controls to advanced Alzheimer's disease stages, including comparative conditions such as Lewy body disease and limbic-predominant age-related TDP-43 encephalopathy neuropathological change. Using stereological sampling and digital pathology, we assessed populations of ramified, hypertrophic and dystrophic microglia. We found a significant increase in dystrophic microglia in areas affected early by Alzheimer's disease neuropathological change, suggesting a disease-specific role in neuropathology. Mediation analysis and structural equation modelling suggest that dystrophic microglia might impact the regional spread of Alzheimer's disease neuropathological change. In the mediation model, tau was found to be the initiating factor leading to the development of dystrophic microglia, which was then associated with the spread of amyloid-β and tau. These results suggest that a loss of the protective role of microglia could contribute to the spread of Alzheimer's disease neuropathological change and indicate that further research into preserving microglial function might be warranted.

All-Trans Retinoic Acid-Induced Cell Surface Heat Shock Protein 90 Mediates Tau Protein Internalization and Degradation in Human Microglia

This study investigates the role of all-trans retinoic acid (ATRA) in modulating the expression of heat shock protein 90 (Hsp90) and its influence on the uptake and degradation of tau proteins in immortalized human microglia cells. We demonstrate that ATRA significantly upregulates Hsp90 expression in a concentration-dependent manner, enhancing both extracellular and intracellular Hsp90 levels. Our results show that ATRA-treated cells exhibit increased tau protein uptake via caveolae/raft-dependent endocytosis pathways. This uptake is mediated by surface Hsp90, as evidenced by the inhibition of tau internalization using an extracellular Hsp90-selective inhibitor. Further, we establish that the exogenously added full-sized monomeric tau proteins bind to Hsp90. The study also reveals that ATRA-enhanced tau uptake is followed by effective degradation through both lysosomal and proteasomal pathways. We observed a significant reduction in intracellular tau levels in ATRA-treated cells, which was reversed by lysosome or proteasome inhibitors, suggesting the involvement of both degradation pathways. Our findings highlight the potential therapeutic role of ATRA in Alzheimer's disease and related tauopathies. By enhancing Hsp90 expression and facilitating tau degradation, ATRA could contribute to the clearance of pathological tau proteins, offering a promising strategy for mitigating neurodegeneration. This research underscores the need for further exploration into the molecular mechanisms of tau protein internalization and degradation, which could provide valuable insights into the treatment of neurodegenerative diseases.

Ketone body metabolism and the NLRP3 inflammasome in Alzheimer's disease

Alzheimer's disease (AD) is a degenerative brain disorder and the most common form of dementia. AD pathology is characterized by senile plaques and neurofibrillary tangles (NFTs) composed of amyloid-β (Aβ) and hyperphosphorylated tau, respectively. Neuroinflammation has been shown to drive Aβ and tau pathology, with evidence suggesting the nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome as a key pathway in AD pathogenesis. NLRP3 inflammasome activation in microglia, the primary immune effector cells of the brain, results in caspase-1 activation and secretion of IL-1β and IL-18. Recent studies have demonstrated a dramatic interplay between the metabolic state and effector functions of immune cells. Microglial metabolism in AD is of particular interest, as ketone bodies (acetone, acetoacetate (AcAc), and β-hydroxybutyrate (BHB)) serve as an alternative energy source when glucose utilization is compromised in the brain of patients with AD. Furthermore, reduced cerebral glucose metabolism concomitant with increased BHB levels has been demonstrated to inhibit NLRP3 inflammasome activation. Here, we review the role of the NLRP3 inflammasome and microglial ketone body metabolism in AD pathogenesis. We also highlight NLRP3 inflammasome inhibition by several ketone body therapies as a promising new treatment strategy for AD.

Amyloid-β oligomers increase the binding and internalization of tau oligomers in human synapses

In Alzheimer's disease (AD), the propagation and spreading of CNS tau pathology closely correlates with cognitive decline, positioning tau as an attractive therapeutic target. Amyloid beta (Aβ) has been strongly implicated in driving tau spread, whereas primary tauopathies such as primary age-related tauopathy (PART)-which lack Aβ pathology-exhibit limited tau spread and minimal-to-no cognitive decline. Emerging evidence converges on a trans-synaptic mechanism of tau spread, facilitated by the transfer of misfolded tau aggregates (e.g. soluble oligomers). However, it is unclear whether Aβ oligomers modulate the binding and internalization of tau oligomers in human synapses. Our translationally focused paradigms utilize post-mortem brain specimens from Control, PART, and AD patients. Synaptosomes isolated from the temporal cortex of all three groups were incubated with preformed recombinant tauO (rtauO), ± preformed recombinant AβO (rAβO), and oligomer binding/internalization was quantified via flow cytometry following proteinase K (PK) digestion of surface-bound oligomers. TauO-synapse interactions were visualized using EM immunogold. Brain-derived tau oligomers (BDTO) from AD and PART PBS-soluble hippocampal fractions were co-immunoprecipitated and analyzed via mass spectrometry to compare synaptic tauO interactomes in primary and secondary tauopathies, thereby inferring the role of Aβ. AD synaptosomes, enriched in endogenous Aβ pathology, exhibited increased rtauO internalization compared to PART synaptosomes. This observation was mirrored in Control synaptosomes, where recombinant rAβO significantly increased rtauO binding and internalization. PK pre-treatment abolished this effect, implicating synaptic membrane proteins in AβO-mediated tauO internalization. While both PART and AD BDTO were broadly enriched in synaptic proteins, AD BDTO exhibited differential enrichment of endocytic proteins across pre- and post-synaptic compartments, whereas PART BDTO showed no significant synaptic enrichment. This study demonstrates that Aβ oligomers enhance tau oligomer binding and drive its internalization through synaptic membrane proteins. These findings offer novel mechanistic insights underlying pathological tau spreading directly within human synapses and emphasize the therapeutic potential of targeting Aβ-tau interactions.

Tau Accumulation Induces Microglial State Alterations in Alzheimer's Disease Model Mice

Unique microglial states have been identified in Alzheimer's disease (AD) model mice and postmortem AD brains. Although it has been well documented that amyloid-β accumulation induces the alteration of microglial states, the relationship between tau pathology and microglial states remains incompletely understood because of a lack of suitable AD models. In the present study, we generated a novel AD model mouse by the intracerebral administration of tau purified from human brains with primary age-related tauopathy into App knock-in mice with humanized tau. Immunohistochemical analyses revealed that Dectin-1-positive disease-associated microglia were increased in the AD model mice after tau accumulation in the brain. We then performed single-nucleus RNA sequencing on the AD model mice to evaluate the differences in microglial states with and without tau propagation and accumulation. By taking advantage of spatial transcriptomics and existing single-cell RNA sequencing datasets, we showed for the first time that tau propagation and accumulation induce a disease-associated microglial phenotype at the expense of an age-related nonhomeostatic counterpart (namely, white matter-associated microglia) in an AD model mouse brain. Future work using spatial transcriptomics at single-cell resolution will pave the way for a more appropriate interpretation of microglial alterations in response to tau pathology in the AD brain.

Tlr7 drives sex differences in age- and Alzheimer's disease-related demyelination

Alzheimer's disease (AD) and other age-related disorders associated with demyelination exhibit sex differences. In this work, we used single-nuclei transcriptomics to dissect the contributions of sex chromosomes and gonads in demyelination and AD. In a mouse model of demyelination, we identified the roles of sex chromosomes and gonads in modifying microglia and oligodendrocyte responses before and after myelin loss. In an AD-related mouse model expressing APOE4, XY sex chromosomes heightened interferon (IFN) response and tau-induced demyelination. The X-linked gene, Toll-like receptor 7 (Tlr7), regulated sex-specific IFN response to myelin. Deletion of Tlr7 dampened sex differences while protecting against demyelination. Administering TLR7 inhibitor mitigated tau-induced motor impairment and demyelination in male mice, indicating that Tlr7 plays a role in the male-biased type I Interferon IFN response in aging- and AD-related demyelination.

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.

Cellular and pathological functions of tau

Tau protein is involved in various cellular processes, including having a canonical role in binding and stabilization of microtubules in neurons. Tauopathies are neurodegenerative diseases marked by the abnormal accumulation of tau protein aggregates in neurons, as seen, for example, in conditions such as frontotemporal dementia and Alzheimer disease. Mutations in tau coding regions or that disrupt tau mRNA splicing, tau post-translational modifications and cellular stress factors (such as oxidative stress and inflammation) increase the tendency of tau to aggregate and interfere with its clearance. Pathological tau is strongly implicated in the progression of neurodegenerative diseases, and the propagation of tau aggregates is associated with disease severity. Recent technological advancements, including cryo-electron microscopy and disease models derived from human induced pluripotent stem cells, have increased our understanding of tau-related pathology in neurodegenerative conditions. Substantial progress has been made in deciphering tau aggregate structures and the molecular mechanisms that underlie protein aggregation and toxicity. In this Review, we discuss recent insights into the diverse cellular functions of tau and the pathology of tau inclusions and explore the potential for therapeutic interventions.

TLR2 immunotherapy suppresses neuroinflammation, tau spread, and memory loss in rTg4510 mice

In Alzheimer's disease, chronic neuroinflammation is accompanied by amyloid and tau pathologies. Especially, aberrant microglial activation is known to precede the regional tau pathology development, but the mechanisms how microglia affect tau spread remain largely unknown. Here, we found that toll-like receptor 2 (TLR2) in microglia recognizes oligomeric tau as a pathogenic ligand and induces inflammatory responses. Knockout of TLR2 reduced tau pathology and microglial activation in rTg4510 tau transgenic mice. Treatment of oligomeric tau induced TLR2 activation and increased inflammatory responses in microglial cells. TLR2 further mediated the tau-induced microglial activation and promoted tau uptake into neurons in neuron-microglia co-culture system and in mouse hippocampus after intracranial tau injection. Importantly, treatment with anti-TLR2 monoclonal antibody Tomaralimab blocked TLR2 activation and inflammatory responses in a dose-dependent manner, and significantly reduced tau spread and memory loss in rTg4510 mice. These results suggest that TLR2 plays a crucial role in tau spread by causing aberrant microglial activation in response to pathological tau, and blocking TLR2 with immunotherapy may ameliorate tau pathogenesis in Alzheimer's disease.

Generation of an inducible destabilized-domain Cre mouse line to target disease associated microglia

The function of microglia during progression of Alzheimer's disease (AD) can be investigated using mouse models that enable genetic manipulation of microglial subpopulations in a temporal manner. We developed a mouse strain that expresses destabilized-domain Cre recombinase (DD-Cre) from the Cst7 locus ( Cst7 DD-Cre ) and tested this in 5xFAD amyloidogenic, Ai14 tdTomato cre-reporter line mice. Dietary administration of trimethoprim to induce DD-Cre activity produces long-term labeling in disease associated microglia (DAM) without evidence of leakiness, with tdTomato-expression restricted to cells surrounding plaques. Using this model, we found that DAMs are a subset of plaque-associated microglia (PAMs) and their transition to DAM increases with age and disease stage. Spatial transcriptomic analysis revealed that tdTomato+ cells show higher expression of disease and inflammatory genes compared to other microglial populations, including non-labeled PAMs. This model should allow inducible cre-loxP targeting of DAMs, without leakiness.

Highlights

We developed a new mouse strain which specifically enables recombination of loxP sites in disease associated microglia (DAMs) and can be used to manipulate DAM-gene expression.DAMs represent a subset of plaque associated microglia (PAMs), and DAM expression increases with disease progression.Spatial transcriptomic analyses reveal that DAMs have higher expression of disease and inflammatory genes compared to other PAMs.

Neuroinflammation Parallels 18F-PI-2620 Positron Emission Tomography Patterns in Primary 4-Repeat Tauopathies

BACKGROUND

Preclinical, postmortem, and positron emission tomography (PET) imaging studies have pointed to neuroinflammation as a key pathophysiological hallmark in primary 4-repeat (4R) tauopathies and its role in accelerating disease progression.

OBJECTIVE

We tested whether microglial activation (1) progresses in similar spatial patterns as the primary pathology tau spreads across interconnected brain regions, and (2) whether the degree of microglial activation parallels tau pathology spreading.

METHODS

We examined in vivo associations between tau aggregation and microglial activation in 31 patients with clinically diagnosed 4R tauopathies, using 18F-PI-2620 PET and 18F-GE180 (translocator protein [TSPO]) PET. We determined tau epicenters, defined as subcortical brain regions with highest tau PET signal, and assessed the connectivity of tau epicenters to cortical regions of interest using a 3-T resting-state functional magnetic resonance imaging template derived from age-matched healthy elderly controls.

RESULTS

In 4R tauopathy patients, we found that higher regional tau PET covaries with elevated TSPO-PET across brain regions that are functionally connected to each other (β = 0.414, P < 0.001). Microglial activation follows similar distribution patterns as tau and distributes primarily across brain regions strongly connected to patient-specific tau epicenters (β = -0.594, P < 0.001). In these regions, microglial activation spatially parallels tau distribution detectable with 18F-PI-2620 PET.

CONCLUSIONS

Our findings indicate that the spatial expansion of microglial activation parallels tau distribution across brain regions that are functionally connected to each other, suggesting that tau and inflammation are closely interrelated in patients with 4R tauopathies. The combination of in vivo tau and inflammatory biomarkers could therefore support the development of immunomodulatory strategies for disease-modifying treatments in these conditions. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Microglia either promote or restrain TRAIL-mediated excitotoxicity caused by Aβ1-42 oligomers

BACKGROUND

Alzheimer's disease (AD) features progressive neurodegeneration and microglial activation that results in dementia and cognitive decline. The release of soluble amyloid (Aβ) oligomers into the extracellular space is an early feature of AD pathology. This can promote excitotoxicity and microglial activation. Microglia can adopt several activation states with various functional outcomes. Protective microglial activation states have been identified in response to Aβ plaque pathology in vivo. However, the role of microglia and immune mediators in neurotoxicity induced by soluble Aβ oligomers is unclear. Further, there remains a need to identify druggable molecular targets that promote protective microglial states to slow or prevent the progression of AD.

METHODS

Hippocampal entorhinal brain slice culture (HEBSC) was employed to study mechanisms of Aβ1-42 oligomer-induced neurotoxicity as well as the role of microglia. The roles of glutamate hyperexcitation and immune signaling in Aβ-induced neurotoxicity were assessed using MK801 and neutralizing antibodies to the TNF-related apoptosis-inducing ligand (TRAIL) respectively. Microglial activation state was manipulated using Gi-hM4di designer receptor exclusively activated by designer drugs (DREADDs), microglial depletion with the colony-stimulating factor 1 receptor (CSF1R) antagonist PLX3397, and microglial repopulation (PLX3397 withdrawal). Proteomic changes were assessed by LC-MS/MS in microglia isolated from control, repopulated, or Aβ-treated HEBSCs.

RESULTS

Neurotoxicity induced by soluble Aβ1-42 oligomers involves glutamatergic hyperexcitation caused by the proinflammatory mediator and death receptor ligand TRAIL. Microglia were found to have the ability to both promote and restrain Aβ-induced toxicity. Induction of microglial Gi-signaling with hM4di to prevent pro-inflammatory activation blunted Aβ neurotoxicity, while microglial depletion with CSF1R antagonism worsened neurotoxicity caused by Aβ as well as TRAIL. HEBSCs with repopulated microglia, however, showed a near complete resistance to Aβ-induced neurotoxicity. Comparison of microglial proteomes revealed that repopulated microglia have a baseline anti-inflammatory and trophic phenotype with a predicted pathway activation that is nearly opposite that of Aβ-exposed microglia. mTORC2 and IRF7 were identified as potential targets for intervention.

CONCLUSION

Microglia are key mediators of both protection and neurodegeneration in response to Aβ. Polarizing microglia toward a protective state could be used as a preventative strategy against Aβ-induced neurotoxicity.

Altered brain connectivity in mild cognitive impairment is linked to elevated tau and phosphorylated tau, but not to GAP-43 and Amyloid-β measurements: a resting-state fMRI study

Mild Cognitive Impairment (MCI) is a neurological condition characterized by a noticeable decline in cognitive abilities that falls between normal aging and dementia. Along with some biomarkers like GAP-43, Aβ, tau, and P-tau, brain activity and connectivity are ascribed to MCI; however, the link between brain connectivity changes and such biomarkers in MCI is still being investigated. This study explores the relationship between biomarkers like GAP-43, Aβ, tau, and P-tau, and brain connectivity. We enrolled 25 Participants with normal cognitive function and 23 patients with MCI. Levels of GAP-43, Aβ1-42, t-tau, and p-tau181p in the CSF were measured, and functional connectivity measures including ROI-to-voxel (RV) correlations and the DMN RV-ratio were extracted from the resting-state fMRI data. P-values below 0.05 were considered significant. The results showed that in CN individuals, higher connectivity within the both anterior default mode network (aDMN) and posterior DMN (pDMN) was associated with higher levels of the biomarker GAP-43. In contrast, MCI individuals showed significant negative correlations between DMN connectivity and levels of tau and P-tau. Notably, no significant correlations were found between Aβ levels and connectivity measures in either group. These findings suggest that elevated levels of GAP-43 indicate increased functional connectivity in aDMN and pDMN. Conversely, elevated levels of tau and p-tau can disrupt connectivity through various mechanisms. Thus, the accumulation of tau and p-tau can lead to impaired neuronal connectivity, contributing to cognitive decline.

Inflammatory aspects of Alzheimer's disease

Alzheimer´s disease (AD) stands out as the most common chronic neurodegenerative disorder. AD is characterized by progressive cognitive decline and memory loss, with neurodegeneration as its primary pathological feature. The role of neuroinflammation in the disease course has become a focus of intense research. While microglia, the brain's resident macrophages, have been pivotal to study central immune inflammation, recent evidence underscores the contributions of other cellular entities to the neuroinflammatory process. In this article, we review the inflammatory role of microglia and astrocytes, focusing on their interactions with AD's core pathologies, amyloid beta deposition, and tau tangle formation. Additionally, we also discuss how different modes of regulated cell death in AD may impact the chronic neuroinflammatory environment. This review aims to highlight the evolving landscape of neuroinflammatory research in AD and underscores the importance of considering multiple cellular contributors when developing new therapeutic strategies.

Frontiers and hotspots evolution in anti-inflammatory studies for Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disorder that seriously affects the quality of the elderly's lives worldwide. The main pathological features of AD are amyloid plaques formed by β-amyloid (Aβ) and neuronal fibrillary tangls (NFTs) formed by hyperphosphorylated Tau protein. The formation process of these pathological features is closely related to inflammatory response, so anti-inflammatory treatment has become a potential treatment for AD. In recent years, more and more research has shown that the anti-inflammatory therapy can relieve the symptoms of AD and improve cognitive function, which provides a valuable research direction for the treatment of AD strategy. Therefore, a comprehensive understanding of the hotspots and development trends of AD anti-inflammatory research is important for promoting the further development of this field and improving the quality of life of patients.

METHODS

This study used bibliometric methods, with AD and anti-inflammatory as key words, collected 7638 AD anti-inflammatory studies collected in Web of Science Core Collection (WoSCC) literature database since 2000, and conducted an in-depth analysis of the research hotspots and potential trends in this field.

RESULTS

The depth and breadth of AD anti-inflammatory research are in the stage of rapid development, and the hot focus is on exploring the role of inflammation in the pathogenesis of AD, especially the interaction of microglia in the neuroinflammatory mechanism. Secondly, the treatment effect and potential risks of anti-inflammatory drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) on AD are also the focus of research. Therefore, researchers have carried out a series of animal experiments and prospective clinical studies on anti-inflammatory drugs for the treatment of AD, forming a comprehensive research system from basic research to clinical research. As for the future development trend, we believe that the further exploration of inflammation in the pathogenesis of AD will still be one of the key directions, and the application of big data and artificial intelligence technology is expected to provide strong support for the association between inflammation and AD progression. Moreover, the development of novel anti-inflammatory drugs for the inflammatory mechanism of AD will be another major trend for future research. At the same time, personalized treatment strategies and alternative supplements of medicine will also become one of the hotspots of future research. Through the comprehensive use of anti-inflammatory drugs, nutritional supplements, lifestyle intervention and other means, more comprehensive and effective treatment plans for AD patients are expected.

CONCLUSION

This research analyzes the overall development trend of AD anti-inflammatory research field since 2000, and provides a comprehensive perspective for the progress of AD anti-inflammatory research. Overall, the field of AD anti-inflammatory research is facing a broad development prospect. In the future, with further research and technological advances, we have resason to expect more effective and safer treatment options for AD patients to help them improve their quality of life and delay disease progression.