bims-microg 2025-06-15 papers

bims-microg

Biomed News

on Microglia in health and disease

Issue of 2025–06–15
thirty papers selected by
Marcus Karlstetter, Universität zu Köln

Early life high fructose impairs microglial phagocytosis and neurodevelopment.
Mamma MIA! Decidual NK cells involved in fetal neurodevelopment.
Protective exercise responses in the dentate gyrus of Alzheimer's disease mouse model revealed with single-nucleus RNA-sequencing.
On-demand microglia deliver the therapeutic payload in Alzheimer's disease.
Boosting angiotensin-converting enzyme (ACE) in microglia protects against Alzheimer's disease in 5xFAD mice.
Iterative transcription factor screening enables rapid generation of microglia-like cells from human iPSC.
Microglial SIRT2 deficiency aggravates cognitive decline and amyloid pathology in Alzheimer's disease.
Prenatal opioid exposure and maternal HCV infection impair microglia development and function: A patient-specific in vitro model.
Early life behavioral deficits and microglia remodeling in the mesocorticolimbic system precede the emergence of Schizophrenia-like symptoms.
Microglia-derived extracellular vesicles mediate fine particulate matter-induced Alzheimer's disease-like behaviors through the miR-34a-5p/DUSP10/p-p38 MAPK pathway.
Coordination acid-engineered Prussian Blue affects glycometabolic reprogramming in microglia for epileptic treatment.
OTUD1 exacerbates sepsis-associated encephalopathy by promoting HK2 mitochondrial release to drive microglia pyroptosis.
Comprehensive analysis of immunoglobulin expression in the mouse brain from embryonic to adult stages.
HIV-1 Tat mediates microglial NLRP3 inflammasome activation and neurotoxicity by inducing cytosolic mtDNA stress.
A novel phosphodiesterase 4/5 dual-target inhibitor ameliorates neuroinflammation via the NF-κB and JNK pathway.
Exploring the role of neutrophils in inflammatory pain hypersensitivity via single-cell transcriptome profiling.
VPAC1 and VPAC2 Receptor Heterozygosity Confers Distinct Biological Properties to BV2 Microglial Cells.
Absence of Microglial Activation and Maintained Hippocampal Neurogenesis in a Transgenic Mouse Model of Crohn's Disease.
Idebenone Mitigates Traumatic-Brain-Injury-Triggered Gene Expression Changes to Ephrin-A and Dopamine Signaling Pathways While Increasing Microglial Genes.
Modulation of ER Stress and Inflammation by S-Ketamine, R-Ketamine, and Their Metabolites in Human Microglial Cells: Insights into Novel Targets for Depression Therapy.
Porphyromonas gingivalis-Lipopolysaccharide Induced Caspase-4 Dependent Noncanonical Inflammasome Activation Drives Alzheimer's Disease Pathologies.
Effect of Microglial Activity on Gut Microbiota in Rats with Neuropathic Pain.
Ergolide Regulates Microglial Activation and Inflammatory-Mediated Dysfunction: A Role for the Cysteinyl Leukotriene Pathway.
IRF8-Cathepsin S/PAR2 axis-mediated spinal microglia-neuron crosstalk is responsible for the exacerbation of postsurgical pain induced by preoperative stress.
Pharmacological Inhibition of Mitochondrial Division Attenuates Simulated High-Altitude Exposure-Induced Memory Impairment in Mice: Involvement of Inhibition of Microglia-Mediated Synapse Elimination.
Metformin protects against insulin resistance-related dementia risk involving restored microglial homeostasis.
CD73 inhibitor AB680 suppresses glioblastoma in mice by inhibiting purine metabolism and promoting P2RY12+ microglia transformation.
Nasal-to-brain delivery of CCR5 antagonist for reshaping the dysregulated microglia-neuron axis and enhancing post-traumatic cognitive function.
Electrode stimulation parameter modifications elicit differential glial cell responses in vitro over a short 4-h timecourse.
Cerebrospinal fluid and brain positron emission tomography measures of synaptic vesicle glycoprotein 2A: Biomarkers of synaptic density in Alzheimer's disease.

Nature. 2025 Jun 11.

Early life high fructose impairs microglial phagocytosis and neurodevelopment.

Zhaoquan Wang, Allie Lipshutz, Celia Martínez de la Torre, Alissa J Trzeciak, Zong-Lin Liu, Isabella C Miranda, Tomi Lazarov, Ana C Codo, Jesús E Romero-Pichardo, Achuth Nair, Tanya Schild, Waleska Saitz Rojas, Pedro H V Saavedra, Ann K Baako, Kelvin Fadojutimi, Michael S Downey, Frederic Geissmann, Giuseppe Faraco, Li Gan, Jon Iker Etchegaray, Christopher D Lucas, Marina Tanasova, Christopher N Parkhurst, Melody Y Zeng, Kayvan R Keshari, Justin S A Perry.

Despite the success of fructose as a low-cost food additive, epidemiological evidence suggests that high fructose consumption during pregnancy or adolescence is associated with disrupted neurodevelopment1-3. An essential step in appropriate mammalian neurodevelopment is the phagocytic elimination of newly formed neurons by microglia, the resident professional phagocyte of the central nervous system4. Whether high fructose consumption in early life affects microglial phagocytosis and whether this directly affects neurodevelopment remains unknown. Here we show that offspring born to female mice fed a high-fructose diet and neonates exposed to high fructose exhibit decreased phagocytic activity in vivo. Notably, deletion of the high-affinity fructose transporter GLUT5 (also known as SLC2A5) in neonatal microglia completely reversed microglia phagocytic dysfunction, suggesting that high fructose directly affects neonatal development by suppressing microglial phagocytosis. Mechanistically, we found that high-fructose treatment of mouse and human microglia suppresses phagocytosis capacity, which is rescued in GLUT5-deficient microglia. Additionally, we found that high fructose drives significant GLUT5-dependent fructose uptake and catabolism to fructose 6-phosphate, rewiring microglial metabolism towards a hypo-phagocytic state in part by enforcing mitochondrial localization of the enzyme hexokinase 2. Mice exposed to high fructose as neonates develop anxiety-like behaviour as adolescents-an effect that is rescued in GLUT5-deficient mice. Our findings provide a mechanistic explanation for the epidemiological observation that high-fructose exposure during early life is associated with increased prevalence of adolescent anxiety disorders.

DOI: https://doi.org/10.1038/s41586-025-09098-5
Immunity. 2025 Jun 10. pii: S1074-7613(25)00231-6. [Epub ahead of print]58(6): 1364-1366

Mamma MIA! Decidual NK cells involved in fetal neurodevelopment.

Norman Shreeve, Francesco Colucci.

Maternal immune activation (MIA) can cause neurodevelopmental disorders, but the underlying mechanisms are incompletely understood. In this issue of Immunity, Bian et al. show that MIA triggers decidual NK cells to secrete granzyme B, which crosses the placenta and disturbs microglial homeostasis in the fetal brain, leading to abnormal neurodevelopment.

DOI: https://doi.org/10.1016/j.immuni.2025.05.010
Nat Neurosci. 2025 Jun 12.

Protective exercise responses in the dentate gyrus of Alzheimer's disease mouse model revealed with single-nucleus RNA-sequencing.

Joana F da Rocha, Michelle L Lance, Renhao Luo, Pius Schlachter, Luis Moreira, Mohamed Ariff Iqbal, Paula Kuhn, Robert S Gardner, Sophia Valaris, Mohammad R Islam, Gabriele M Gassner, Sofia Mazuera, Kaela Healy, Sanjana Shastri, Nathaniel B Hibbert, Kristen V Moran-Figueroa, Erin B Haley, Ryan D Pfeiffer, Sema Aygar, Ksenia V Kastanenka, Logan Brase, Oscar Harari, Bruno A Benitez, Nathan R Tucker, Christiane D Wrann.

Exercise's protective effects in Alzheimer's disease (AD) are well recognized, but cell-specific contributions to this phenomenon remain unclear. Here we used single-nucleus RNA sequencing (snRNA-seq) to dissect the response to exercise (free-wheel running) in the neurogenic stem-cell niche of the hippocampal dentate gyrus in male APP/PS1 transgenic AD model mice. Transcriptomic responses to exercise were distinct between wild-type and AD mice, and most prominent in immature neurons. Exercise restored the transcriptional profiles of a proportion of AD-dysregulated genes in a cell type-specific manner. We identified a neurovascular-associated astrocyte subpopulation, the abundance of which was reduced in AD, whereas its gene expression signature was induced with exercise. Exercise also enhanced the gene expression profile of disease-associated microglia. Oligodendrocyte progenitor cells were the cell type with the highest proportion of dysregulated genes recovered by exercise. Last, we validated our key findings in a human AD snRNA-seq dataset. Together, these data present a comprehensive resource for understanding the molecular mediators of neuroprotection by exercise in AD.

DOI: https://doi.org/10.1038/s41593-025-01971-w
Cell Stem Cell. 2025 Jun 05. pii: S1934-5909(25)00183-3. [Epub ahead of print]32(6): 859-861

On-demand microglia deliver the therapeutic payload in Alzheimer's disease.

Jessica M Thanos, John R Lukens.

In this issue, Chadarevian et al. showed that engraftment of human iPSC-derived microglia (iMG) engineered to express secreted neprilysin (sNEP) under the plaque-responsive CD9 promoter reduces amyloid burden, neuronal damage, and inflammation in an Alzheimer's disease (AD) mouse model.1 These findings establish a cell-based strategy to treat neurological diseases.

DOI: https://doi.org/10.1016/j.stem.2025.05.003
Nat Aging. 2025 Jun 09.

Boosting angiotensin-converting enzyme (ACE) in microglia protects against Alzheimer's disease in 5xFAD mice.

Andrew R Gomez, Hyae Ran Byun, Shaogen Wu, A K M Ghulam Muhammad, Jasmine Ikbariyeh, Jaelin Chen, Alek Muro, Lin Li, Kenneth E Bernstein, Richard Ainsworth, Warren G Tourtellotte.

Genome-wide association studies have identified many gene polymorphisms associated with an increased risk of developing late-onset Alzheimer's disease (LOAD). Many of these LOAD risk-associated alleles alter disease pathogenesis by influencing innate immune responses and lipid metabolism of microglia (MG). Here we show that boosting the expression of angiotensin-converting enzyme (ACE), a genome-wide association study LOAD risk-associated gene product, specifically in MG, reduces amyloid-β (Aβ) plaque load, preserves vulnerable neurons and excitatory synapses, and significantly reduces learning and memory abnormalities in the 5xFAD amyloid mouse model of AD. ACE-expressing MG surround plaques more frequently and they have increased Aβ phagocytosis, endolysosomal trafficking and spleen tyrosine kinase activation downstream of the major Aβ receptors, triggering receptor expressed on myeloid cells 2 (Trem2) and C-type lectin domain family 7 member A (Clec7a). These findings establish a role for ACE in enhancing microglial immune function and they identify a potential use for ACE-expressing MG as a cell-based therapy to augment endogenous microglial responses to Aβ in AD.

DOI: https://doi.org/10.1038/s43587-025-00879-1
Nat Commun. 2025 Jun 10. 16(1): 5136

Iterative transcription factor screening enables rapid generation of microglia-like cells from human iPSC.

Songlei Liu, Li Li, Fan Zhang, Mariana Garcia-Corral, Katharina Meyer, Patrick R J Fortuna, Björn van Sambeek, Evan Appleton, Alex H M Ng, Parastoo Khoshakhlagh, Yuancheng Ryan Lu, James Cameron, Ricardo N Ramirez, Yuting Chen, Chun-Ting Wu, Jeremy Y Huang, Yuqi Tan, George Chao, John Aach, Elaine T Lim, Jenny M Tam, Soumya Raychaudhuri, George M Church.

Differentiation of induced pluripotent stem cells (iPSCs) into specialized cell types is essential for uncovering cell-type specific molecular mechanisms and interrogating cellular function. Transcription factor screens have enabled efficient production of a few cell types; however, engineering cell types that require complex transcription factor combinations remains challenging. Here, we report an iterative, high-throughput single-cell transcription factor screening method that enables the identification of transcription factor combinations for specialized cell differentiation, which we validated by differentiating human microglia-like cells. We found that the expression of six transcription factors, SPI1, CEBPA, FLI1, MEF2C, CEBPB, and IRF8, is sufficient to differentiate human iPSC into cells with transcriptional and functional similarity to primary human microglia within 4 days. Through this screening method, we also describe a novel computational method allowing the exploration of single-cell RNA sequencing data derived from transcription factor perturbation assays to construct causal gene regulatory networks for future cell fate engineering.

DOI: https://doi.org/10.1038/s41467-025-59596-3
Brain Behav Immun. 2025 Jun 09. pii: S0889-1591(25)00227-2. [Epub ahead of print]

Microglial SIRT2 deficiency aggravates cognitive decline and amyloid pathology in Alzheimer's disease.

Noemi Sola-Sevilla, Maider Garmendia-Berges, Mikel Aleixo, MCarmen Mera-Delgado, Maite Solas, Rosa M Tordera, Lucía García-Carracedo, Sara Expósito, Elena Anaya-Cubero, Joaquín Fernández-Irigoyen, Elisabeth Guruceaga, Enrique Santamaria, Eduardo D Martin, Elena Puerta.

  Sirtuin 2 (SIRT2), a NAD+-dependent deacetylase, has been implicated in aging and neurodegenerative diseases such as Alzheimer's disease (AD). While global SIRT2 inhibition has shown promise in reducing amyloid-beta pathology and cognitive deficits in different mouse models of AD, peripheral SIRT2 inhibition has been associated with adverse effects, such as increased inflammation. This suggests that targeted inhibition of specific cellular populations within the brain may represent a more precise and effective approach for the treatment of AD. To explore this hypothesis, we generated a conditional microglial SIRT2 knockout mouse model in the context of AD. Our results reveal that microglial SIRT2 reduction does not confer protective effects in the APP/PS1 model; rather, it aggravates cognitive decline, accelerates amyloid plaque deposition, and increases levels of pro-inflammatory cytokines at early stages of AD pathology. Transcriptomic analysis further indicates that SIRT2-deficient microglia exhibit altered expression of genes associated with aging and synaptic dysfunction. This phenotype was accompanied by increased phagocytosis of PSD95 and impaired long-term potentiation. These findings suggest that while SIRT2 inhibition in some contexts may be beneficial, targeted inhibition within microglia could accelerate AD progression, underscoring the need for cell-specific approaches when considering SIRT2 as a therapeutic target.

Keywords:  Aging; Alzheimer’s disease; Microglia; Neurodegenerative diseases; Neuroinflammation; Sirtuin 2

DOI:  https://doi.org/10.1016/j.bbi.2025.06.016
Brain Behav Immun. 2025 Jun 09. pii: S0889-1591(25)00224-7. [Epub ahead of print]129 206-220

Prenatal opioid exposure and maternal HCV infection impair microglia development and function: A patient-specific in vitro model.

Heather E True, Hami Hemati, Rebecca Geron, Brianna M Doratt, Delphine C Malherbe, Cynthia Cockerham, John O'Brien, Ilhem Messaoudi.

  Opioids are a class of pain-relieving drugs known to cross the placental and blood brain barriers, exposing the fetus in utero. Rates of opioid use disorder amongst pregnant individuals in the United States are on the rise, and intravenous routes of opioid administration are highly associated with hepatitis C (HCV) infection. Newborns with prenatal opioid exposure (POE) are more likely to be small for gestational age and have increased rates of neurodevelopmental delay. Microglia are brain-resident macrophages that originate from yolk-sac precursors that play critical role in neurodevelopment. However, our understanding of the impact of POE on microglia maturation and function remains limited due to the scarcity of adequate models. Here, we leveraged a model of induced microglia-like cells (iMGL) derived from umbilical cord blood mononuclear cells to uncover the mechanisms underlying the impact of POE ± maternal HCV infection on microglia morphology, phenotype, function, and transcriptional profiles. Our study revealed that iMGL are closely related to primary microglia. iMGL derived from pregnancies with POE and maternal HCV infection exhibited an ameboid-like phenotype, characterized by smaller area/perimeter and diminished ramifications. This was accompanied by dysregulated expression of key microglia markers, impaired phagocytic capacity, but increased secretion of inflammatory mediators. Finally, transcriptional analysis of iMGL with and without stimulation by LPS revealed that POE ± maternal HCV infection desensitized iMGL to LPS stimulation. This immune tolerance of iMGL in utero was reflected by altered expression of genes important for neurological and fetal development, phagocytosis, and antimicrobial responses with POE ± maternal HCV infection. Overall, these findings highlight the utility of iMGLs as an accessible patient-specific model to study preconditioning and development of fetal microglia and provide insight into mechanisms underlying adverse neurodevelopmental outcomes in newborns with POE in presence and absence of maternal HCV infection.

Keywords:  Microglia; Morphology; Neurodevelopment; Opioid; Pregnancy; Transcriptome; hepatitis C

DOI:  https://doi.org/10.1016/j.bbi.2025.06.010
Brain Behav Immun. 2025 Jun 10. pii: S0889-1591(25)00223-5. [Epub ahead of print]

Early life behavioral deficits and microglia remodeling in the mesocorticolimbic system precede the emergence of Schizophrenia-like symptoms.

Ana C Rodrigues-Neves, Jéssica Monteiro, Bárbara Coimbra, Rita Gaspar, Verónica Domingues, Carina Soares-Cunha, Patrícia Patrício, Marta I Pereira, Ana L Cardoso, Luísa Pinto, João Bessa, Ana J Rodrigues, António F Ambrósio, Catarina A Gomes.

  Microglia-mediated sensing, during development, dictates synapse formation/elimination and function. This depends on microglia morphology, in the sense their cellular processes adopt variable length/degree of ramification, in response to neuronal cues, in turn regulated by local microenvironmental conditions. In schizophrenia, two neuronal pathways of the mesocorticolimbic system are oppositely dysregulated, resulting in hypo- and hyper-dopaminergic tonus in target regions, prefrontal cortex (PFC) and nucleus accumbens (NAc). This bimodal tonus is associated with disease manifestations, including social symptoms. Although schizophrenia is a developmental disease, electrophysiological and behavioral preclinical data have been mainly obtained in adulthood and information about disease trajectory until adolescence (an important period of diagnosis) is very limited. The main goal of the present work is to characterize the morphological differentiation of microglia in PFC and NAc, in infancy and adolescence, using an experimental model of schizophrenia (rats prenatally exposed to methylazoxymethanol acetate, MAM) and to detect early manifestations of neurodevelopmental deficits. In infancy, MAM affects neurodevelopmental milestones and induces microglia hypertrophy in PFC and NAc, in both sexes. In adolescence, social behavior is affected (with subtle differences between sexes) and, notably, a region-specific microglia remodeling is observed: in PFC, there is a recovery of the physiological morphology, but an atrophic phenotype emerges in NAc. Although out of the scope of this work, in an attempt to validate the model in adult females, we screened for sex differences in behavior and (electro)physiology, aspects also discussed. This topic deserves a cautious analysis by the scientific community and reinforces the importance of performing preclinical studies in both sexes.

Keywords:  Microglia; Morphology; Region-specificity; Schizophrenia; Sex-dimorphism

DOI:  https://doi.org/10.1016/j.bbi.2025.06.009
J Hazard Mater. 2025 Jun 06. pii: S0304-3894(25)01769-8. [Epub ahead of print]495 138853

Microglia-derived extracellular vesicles mediate fine particulate matter-induced Alzheimer's disease-like behaviors through the miR-34a-5p/DUSP10/p-p38 MAPK pathway.

Ling Wang, Yi Lin, Ziyi Yang, Ke Zhang, Hongyang Gong, Yaopeng Zheng, Binquan Wang, Xiaoyan Zhang, Mingkuan Sun.

  Fine particulate matter (PM2.5), a major component of air pollution, poses significant global health risks. Epidemiological studies have correlated long-term PM2.5 exposure and neurological disorders, including Alzheimer's disease (AD). Extracellular vesicles (EVs) are recognized as critical mediators of intercellular communication. Understanding the role of microglia EVs in neuronal dysfunction is essential, given the increasing awareness of non-cell-autonomous neurotoxicity. The mechanisms through which microglia and their EVs mediate PM2.5-induced neurotoxicity are poorly understood. This study demonstrated that PM2.5 exposure drives microglial toward the pro-inflammatory M1 phenotype, impairing the brain's immune defenses. PM2.5-treated microglia secrete miR-34a-5p-enriched EVs. These EVs are delivered to neurons, target DUSP10, activate the p-p38 MAPK pathway, increase aberrant tau phosphorylation and pathological Aβ proteins, and induce neuronal apoptosis in the hippocampus and cortical regions. These pathological changes contribute to cognitive and behavioral deficits in PM2.5-exposed mice. Knocking down miR-34a-5p in EVs from PM2.5-treated microglia rescued these phenotypes, mitigating AD-like pathology in mice. Our study identified miR-34a-5p as a critical regulator of neuro apoptosis and AD-like cognitive impairment induced by PM2.5 exposure. These findings underscore the pivotal role of microglial EVs in mediating intercellular communication between glia and neurons, providing valuable insights into the mechanisms underlying PM2.5-induced neurotoxicity.

Keywords:  Alzheimer's disease (AD); DUSP10; Extracellular vesicles (EVs); Fine particles (PM2.5); MiR-34a-5p

DOI:  https://doi.org/10.1016/j.jhazmat.2025.138853
J Nanobiotechnology. 2025 Jun 11. 23(1): 436

Coordination acid-engineered Prussian Blue affects glycometabolic reprogramming in microglia for epileptic treatment.

Yao Zhao, Feixiang Chen, Chen Chen, Yuling Yang, Luo Wang, Jiaqi Zhu, Xin Wang, Yanyan Liu, Jing Ding.

  Seizures induce significant immune and metabolic stress in microglia, but the interaction between these processes remains unclear. This study, utilizing single-nucleus RNA sequencing data from temporal lobe epilepsy (TLE) patients, reveals that reactive oxygen species (ROS) stabilize hypoxia-inducible factor 1-alpha (HIF-1α), thereby inducing glycometabolic reprogramming in microglia and driving the development of a pro-inflammatory phenotype. To address this, a coordination acid-engineered Prussian Blue (PB@ZIF) nanosystem is developed, where Zn²⁺ sites in the zeolitic imidazolate framework (ZIF) lower the local pKa, thereby enhancing the reaction efficiency of PB with free radicals. In vivo experiments using a TLE model demonstrate that PB@ZIF is effectively internalized by microglia and significantly alleviates spontaneous recurrent seizures and seizure-related behaviors. PB@ZIF mitigates microglial inflammatory activation and reduces neuronal injury. Notably, PB@ZIF-induced ROS reduction enhances the enzymatic activity of prolyl hydroxylase domain enzymes, effectively inhibiting HIF-1α-driven glycometabolic reprogramming in microglia. This study identifies a molecular mechanism underlying the immune-metabolic interactions in epilepsy and proposes a promising therapeutic strategy regulating microglial metabolism to improve epilepsy management.

Keywords:  Local pKa; Metabolic reprogramming; Microglia; Nanocatalyst; Temporal lobe epilepsy

DOI:  https://doi.org/10.1186/s12951-025-03408-9
J Neuroinflammation. 2025 Jun 11. 22(1): 154

OTUD1 exacerbates sepsis-associated encephalopathy by promoting HK2 mitochondrial release to drive microglia pyroptosis.

Guoqing Jing, Hailong Gong, Han Wang, Jing Zuo, Die Wu, Huifan Liu, Xing Wang, Min Yuan, Yun Xia, Tongtong Du, Wanhong Liu, Xiaojing Wu, Xuemin Song.

   BACKGROUND: Sepsis-associated encephalopathy (SAE), a life-threatening neurological complication of systemic infection, contributes substantially to sepsis-related mortality. Accumulating evidence demonstrates that microglia-driven neuroinflammation emerges as a central pathogenic mechanism underlying SAE. Here, we identify ovarian tumor deubiquitinase 1 (OTUD1) as a critical mediator of SAE pathogenesis. We demonstrate that OTUD1 promotes hexokinase 2 (HK2) dissociation from mitochondria via selective K63-linked deubiquitination, triggering microglia pyroptosis and neuroinflammation. Our findings address a key knowledge gap by elucidating the OTUD1-HK2 axis as a novel regulatory pathway in SAE, offering potential therapeutic targets to mitigate cognitive deficits in sepsis.
METHODS: Single-cell RNA sequencing was used to identify SAE-specific microglia subpopulations and analyze the expression of deubiquitinases within these subpopulations. OTUD1 knockout mice were generated to investigate the role of OTUD1 in SAE. Both wild-type and OTUD1 knockout mice were subjected to cecal ligation and puncture to induce SAE. In vitro, primary microglia and BV2 cells were treated with LPS and nigericin to simulate inflammatory conditions. Cognitive function of the mice was assessed through behavioral tests. Neuronal and synaptic damage were evaluated using HE and Nissl staining, as well as transmission electron microscopy. ELISA and qPCR were used to detect neuroinflammation. Western blot and immunofluorescence were employed to analyze protein expression. Molecular docking, 3D confocal microscopy, and co-immunoprecipitation were conducted to detect the interaction between OTUD1 and HK2. Finally, the correlation between OTUD1 and SAE was evaluated by analyzing clinical samples.
RESULTS: Through single-cell RNA seq and subpopulation analysis, we identified an SAE-associated microglia (SAM) subpopulation with high expression of pyroptosis-related genes. Deubiquitinase expression analysis showed significantly elevated OTUD1 expression in SAM. OTUD1 deficiency attenuated neural damage and cognitive dysfunction in SAE mice in vivo. Further experiments revealed that OTUD1 regulates pyroptosis in microglia, affecting the progression of SAE. Mechanistically, OTUD1 directly binds to the C-terminal domain of HK2 through its Ala-rich domain and selectively cleaves K63-linked polyubiquitin chains on HK2 to promote the dissociation of HK2 from mitochondria, thereby activating the NLRP3 inflammasome and pyroptosis.
CONCLUSIONS: In SAE, OTUD1 deubiquitinates HK2, promoting its dissociation from mitochondria, which triggers microglia pyroptosis, leading to neuronal damage and cognitive impairment.

Keywords:  HK2; Microglia; OTUD1; Pyroptosis; SAE

DOI:  https://doi.org/10.1186/s12974-025-03480-w
J Neuroinflammation. 2025 Jun 09. 22(1): 153

Comprehensive analysis of immunoglobulin expression in the mouse brain from embryonic to adult stages.

Keiko Morimoto, Hitomi Sano, Michiko Takahashi, Rikuo Takahashi, Kazunori Nakajima.

  Immunoglobulin (Ig) is a critical molecule in the body's defense against foreign substances such as bacteria and viruses. While traditionally considered B cell specific, studies have reported that Ig is also expressed by non-B cells. However, it is not known to what extent Ig is expressed in the brain and which type of variable regions are expressed. In this study, we elucidated the expression profile of Igs from embryonic to adult stages using single-cell RNA sequencing data and Ig repertoire analysis. Our results revealed that microglia express Ighm transcripts from embryonic to adult stages. These transcripts contain the upstream region of the Ighj region. In addition, Ighm is expressed in the layer 6 corticothalamic neurons, some of which co-express Ighg2c in the adult brain. In particular, we were able to generate a comprehensive profile of Ig variable region expression from embryonic to adult stages. Furthermore, the response of Ighm expression in microglia to lipopolysaccharide is markedly different from that in B cells, suggesting a novel, brain-specific role for the Ig gene, distinct from its classical function in the immune system.

Keywords:   Ighm ; Constant region; Immunoglobulin; LPS; Microglia; Neuron; Variable region; scRNA-seq

DOI:  https://doi.org/10.1186/s12974-025-03457-9
Int J Biol Macromol. 2025 Jun 08. pii: S0141-8130(25)05646-6. [Epub ahead of print] 145093

HIV-1 Tat mediates microglial NLRP3 inflammasome activation and neurotoxicity by inducing cytosolic mtDNA stress.

Xiaotian Yang, Pengchun Han, Mengyu Li, Yaxin Xue, Xiangyi Yu, Mingjun Jiang, Huizhen Wang, Juanmei Zhang, Hongliang Liu, Dengke Bao.

  Tat, a regulatory protein of human immunodeficiency virus (HIV)-1, is a potent viral neurotoxin which can activate the NLRP3 inflammasome in microglia and contribute to neurotoxicity. Here, we found that HIV Tat induces mitochondrial dysfunction in microglia and promotes mtDNA leakage into the cytoplasm to activate the NLRP3 inflammasome. Degrading mtDNA with DNase I significantly blocks the activation of NLRP3 inflammasome and IL-1β secretion. Interestingly, we found that HIV Tat promotes the translocation of TDP-43 from nucleus to mitochondria. Furthermore, we found that ROS accumulation mediated by HIV Tat could activate NF-κB signaling pathway to facilitate the transcription of IL-1β precursor. Scavenging intracellular ROS significantly inhibits the activation of the NF-κB signaling pathway, thereby reducing the transcription and secretion of IL-1β. Conditioned medium from microglia treated with Tat significantly induces SH-SY5Y and primary neuronal cell apoptosis, which can be alleviated by GIBH-130. In conclusion, our results suggest that HIV-1 Tat promotes TDP-43 abnormal localization to mitochondria and mitochondrial dysfunction, inducing cytosolic mtDNA stress and ROS accumulation. These events respectively activate the NLRP3 inflammasome and NF-κB signaling pathway, thereby promoting IL-1β secretion and neuronal damage. This study reveals a new underlying mechanism for neuroinflammation mediated by HIV infection.

Keywords:  HIV-1 Tat; Mitochondrial damage-associated molecular pattern; NLRP3 inflammasome

DOI:  https://doi.org/10.1016/j.ijbiomac.2025.145093
Int J Biol Macromol. 2025 Jun 05. pii: S0141-8130(25)05560-6. [Epub ahead of print] 145007

A novel phosphodiesterase 4/5 dual-target inhibitor ameliorates neuroinflammation via the NF-κB and JNK pathway.

Liyun Zhao, Wenjie Jiang, Yingying Cao, Yi-You Huang, Xue Wang, Li Guo, Dongke Yu, Jianyou Shi.

  Targeting neuroinflammation is a promising strategy for developing treatments for neurodegenerative diseases. Cyclic nucleotides like cAMP and cGMP, crucial second messengers in the central nervous system. Phosphodiesterases (PDEs) are the sole enzymes that hydrolyze these nucleotides in vivo. Among them, PDE4-specific hydrolysis of cAMP and PD5-specific hydrolysis of cGMP. We hypothesized that simultaneous inhibition of PDE4 and PDE5 could provide superior therapeutic effects. This hypothesis was tested by combining Rolipram (PDE4 inhibitor) and Tadalafil (PDE5 inhibitor), evaluating their impact on cAMP, cGMP, and inflammatory factors in LPS-induced BV2 cells and APP/PS1 mice, along with cognitive effects in the mice. Additionally, a novel dual-target PDE4/5 inhibitor, C-3-1, was designed, synthesized, and evaluated for its ability to regulate neuroinflammation and improve cognitive functions. RNA sequencing identified gene expression changes and pathway alterations. Our findings indicated that dual inhibition of PDE4 and PDE5 synergistically improved neuroinflammatory responses and cognitive functions. C-3-1 also reduced the activation of microglia and astrocytes and increased neuron numbers. The anti-neuroinflammatory effects of C-3-1 are achieved by affecting NF-κB and JNK pathways, highlighting the potential of multitargeted therapy in neuroinflammation treatment. This research supports the development of combined PDE4/5 inhibitors as effective therapeutic agents for neurodegenerative diseases.

Keywords:  JNK; NF-κB; Neuroinflammation; Neuroprotection; PDE4/5 dual-target inhibitor

DOI:  https://doi.org/10.1016/j.ijbiomac.2025.145007
Front Immunol. 2025 ;16 1552993

Exploring the role of neutrophils in inflammatory pain hypersensitivity via single-cell transcriptome profiling.

Kai Ding, Xing Liu, Bin Zeng, Songyu Liu, Lu Zhang, Bo Li, Jinyi Zhou, Xiaosan Su, Jun Wang.

   Introduction: Myeloid CD11b+ cells are crucial mediators in post-operative and CFA-induced inflammation, but their role in pain, particularly the role of neutrophils, is still debated. This study employs single-cell RNA sequencing (scRNA-seq) to analyze CD11b+ cell composition in mice after surgery and CFA treatment and investigates the effects and mechanisms of Nicotinamide N-oxide (NAMO) on neutrophils and pain.
Methods: scRNA-seq was used to analyze the transcriptomes of CD11b+ cells in murine models of post-operative and CFA-induced inflammation. Using comprehensive bioinformatics techniques, we identified distinct cell subpopulations and characterized their gene expression profiles and functional attributes. Based on these analyses, NAMO was selected to intervene in neutrophil differentiation and maturation. The role of the CXCR2 target gene and NAMO in modulating post-operative and inflammatory pain was then evaluated, exploring potential mechanisms.
Results: scRNA-seq revealed a significant increase in neutrophils and a decrease in monocytes among CD11b+ cells following surgery and CFA treatment. Neutrophils comprised seven subpopulations at various differentiation stages from immature to mature. Given the high expression of CXCR2 in neutrophils, we used the CXCR2 inhibitor NAMO to suppress neutrophil differentiation and maturation, which subsequently alleviated post-operative and CFA-induced pain in mice. Proteomics analysis showed that NAMO treatment significantly reduced the expression of S100b and CaMKIIβ proteins in mouse neutrophils.
Discussion: Following surgery and CFA treatment, mature neutrophils were significantly elevated. The CXCR2 antagonist NAMO alleviated post-surgical and CFA-induced pain by inhibiting neutrophil differentiation and maturation. These findings offer novel approaches for pain prevention and treatment.

Keywords:  CXCR2; NAMO; inflammation; neutrophil; pain

DOI:  https://doi.org/10.3389/fimmu.2025.1552993
Cells. 2025 May 23. pii: 769. [Epub ahead of print]14(11):

VPAC1 and VPAC2 Receptor Heterozygosity Confers Distinct Biological Properties to BV2 Microglial Cells.

Xin Ying Rachel Song, Margo Iris Jansen, Rubina Marzagalli, Giuseppe Musumeci, Velia D'Agata, Alessandro Castorina.

  Microglial cells, the resident immune cells of the central nervous system (CNS), are essential for maintaining CNS homeostasis. Dysregulation of microglial function is implicated in the pathogenesis of various neurodegenerative diseases. Vasoactive intestinal polypeptide receptors 1 and 2 (VPAC1 and VPAC2) are G-protein-coupled receptors (GPCRs) expressed by microglia, with their primary ligands being pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP). However, the specific roles of VPAC-type receptors in microglial regulation remain poorly understood. In this study, we generated VPAC1+/- and VPAC2+/- BV2 microglial cell lines using CRISPR-Cas9 gene editing and conducted a series of biological and molecular assays to elucidate the functions of these receptors. Our findings demonstrated that both mutant cell lines exhibited a polarized phenotype and increased migratory activity. VPAC1+/- cells showed enhanced survivability and baseline activation of the unfolded protein response (UPR), a protective mechanism triggered by endoplasmic reticulum (ER) stress, whereas this response appeared impaired in VPAC2+/- cells. In contrast, under lipopolysaccharide (LPS)-induced inflammatory conditions, UPR activation was impaired in VPAC1+/- cells but restored in VPAC2+/- cells, resulting in improved survival of VPAC2+/- cells, whereas VPAC1+/- cells exhibited reduced resilience. Overall, our findings suggest that VPAC1 and VPAC2 receptors play distinct yet complementary roles in BV2 microglia. VPAC2 is critical for regulating survival, ER stress responses, and polarization under basal conditions, while VPAC1 is essential for adaptive responses to inflammatory stimuli such as LPS. These insights advance our understanding of microglial receptor signaling and may inform therapeutic strategies targeting microglial dysfunction in neurodegenerative diseases.

Keywords:  BV2 cells; ER stress; PACAP; VIP; VPAC1; VPAC2; microglia; neurodegeneration; neuroinflammation; unfolded protein response

DOI:  https://doi.org/10.3390/cells14110769
Cells. 2025 Jun 04. pii: 841. [Epub ahead of print]14(11):

Absence of Microglial Activation and Maintained Hippocampal Neurogenesis in a Transgenic Mouse Model of Crohn's Disease.

Rebecca Katharina Masanetz, Hanna Mundlos, Iris Stolzer, Jürgen Winkler, Claudia Günther, Patrick Süß.

  Adult neurogenesis in the hippocampal dentate gyrus (DG) is not only essential for learning and pattern separation, but it is also involved in emotional regulation. This process is vulnerable to local and peripheral inflammation, which is partly mediated by microglia in the DG. As Crohn's disease (CD) is associated with neuropsychiatric comorbidity, including depression and cognitive impairment, a reduction in adult hippocampal neurogenesis by chronic gut-derived inflammation has been hypothesized. Here, we present the first study that examined the influence of chronic ileocolitis on microglia in the DG and on adult hippocampal neurogenesis in a transgenic mouse model of CD, which is generated by a constitutive knockout of caspase 8 in intestinal epithelial cells (IECs, Casp8ΔIEC mice). Structural and transcriptional analyses revealed that microglial cell proliferation and density in the DG as well as the expression of genes associated with their homeostasis and activation in the forebrain were maintained in 14- and 24-week-old Casp8ΔIEC mice compared to Casp8fl controls. Furthermore, different stages of adult hippocampal neurogenesis, including progenitor cell proliferation, maturation, and apoptosis of newly generated cells, were predominantly unaffected by chronic ileocolitis, except a potential minor phenotypic shift in maturating cells in 24-week-old mice. Together, we demonstrate largely preserved adult hippocampal neurogenesis, lacking signs of local inflammatory microglial activation despite chronic inflammation of the gut.

Keywords:  adult hippocampal neurogenesis; dentate gyrus; gut–immune–brain axis; inflammatory bowel disease; microglia

DOI:  https://doi.org/10.3390/cells14110841
Cells. 2025 Jun 01. pii: 824. [Epub ahead of print]14(11):

Idebenone Mitigates Traumatic-Brain-Injury-Triggered Gene Expression Changes to Ephrin-A and Dopamine Signaling Pathways While Increasing Microglial Genes.

Hyehyun Hwang, Chinmoy Sarkar, Boris Piskoun, Naibo Zhang, Apurva Borcar, Courtney L Robertson, Marta M Lipinski, Nagendra Yadava, Molly J Goodfellow, Brian M Polster.

  Traumatic brain injury (TBI) leads to persistent pro-inflammatory microglial activation implicated in neurodegeneration. Idebenone, a coenzyme Q10 analogue that interacts with both mitochondria and the tyrosine kinase adaptor SHC1, inhibits aspects of microglial activation in vitro. We used the NanoString Neuropathology Panel to test the hypothesis that idebenone post-treatment mitigates TBI-pathology-associated acute gene expression changes by moderating the pro-inflammatory microglial response to injury. Controlled cortical impact to adult male mice increased the microglial activation signature in the peri-lesional cortex at 24 h post-TBI. Unexpectedly, several microglial signature genes upregulated by TBI were further increased by post-injury idebenone administration. However, idebenone significantly attenuated TBI-mediated perturbations to gene expression associated with behavior, particularly in the gene ontology-biological process (GO:BP) pathways "ephrin receptor signaling" and "dopamine metabolic process". Gene co-expression analysis correlated levels of microglial complement component 1q (C1q) and the neurotrophin receptor gene Ntrk1 to large (>3-fold) TBI-induced decreases in dopamine receptor genes Drd1 and Drd2 that were mitigated by idebenone treatment. Bioinformatics analysis identified SUZ12 as a candidate transcriptional regulator of idebenone-modified gene expression changes. Overall, the results suggest that idebenone may enhance TBI-induced microglial number within the first 24 h of TBI and identify ephrin-A and dopamine signaling as novel idebenone targets.

Keywords:  C1Q; CCI; EFNA; EPHA; SHC1; SUZ12; TBI; TRKA; mitochondria; neuroinflammation; neuropathology

DOI:  https://doi.org/10.3390/cells14110824
Cells. 2025 Jun 03. pii: 831. [Epub ahead of print]14(11):

Modulation of ER Stress and Inflammation by S-Ketamine, R-Ketamine, and Their Metabolites in Human Microglial Cells: Insights into Novel Targets for Depression Therapy.

Marta Jóźwiak-Bębenista, Anna Wiktorowska-Owczarek, Małgorzata Siatkowska, Piotr Komorowski, Aneta Włodarczyk, Edward Kowalczyk, Paulina Sokołowska.

  Despite affecting millions worldwide, major depressive disorder (MDD) remains a therapeutic challenge, with approximately one-third of patients failing to respond to standard treatments. The need for innovative, molecularly driven therapies has turned attention to ketamine and its enantiomers. While S-ketamine is clinically approved for treatment-resistant depression (TRD), it has various psychoactive side effects and potential for abuse. Hence, it is necessary to identify alternative compounds, such as R-ketamine, and their metabolites (e.g., 2S,6S-hydroxynorketamine and 2R,6R-hydroxynorketamine, collectively referred to as HNKs). Emerging evidence suggests that the pathophysiology of MDD involves two processes regulated by the unfolded protein response (UPR): endoplasmic reticulum (ER) stress and neuroinflammation. As such, they represent promising therapeutic targets. The study provides the first direct comparison of ketamine enantiomers and their metabolites in modulating ER stress and inflammatory signaling in human microglial cells (HMC3), which play key roles in neuroimmune communication. Both S-ketamine and R-ketamine, along with their metabolites, significantly reduced both the expression and protein levels of CHOP and GRP78-two critical UPR components-under tunicamycin-induced ER stress conditions. Additionally, the compounds significantly decreased IL-6 levels and, to a lesser extent, IL-8 levels in lipopolysaccharide (LPS)-stimulated microglia, indicating anti-inflammatory potential. Taken together, these findings highlight a novel glia-targeted mechanism by which ketamine and its metabolites modulate ER stress and neuroinflammation. CHOP and GRP78 appear to be stress-responsive molecular markers within the UPR pathway. These results justify further in vivo validation and support the development of antidepressants with fewer psychoactive effects.

Keywords:  CHOP; ER stress; GRP78; UPR pathway; antidepressants; depression; inflammation; ketamine; ketamine metabolites; treatment-resistant depression

DOI:  https://doi.org/10.3390/cells14110831
Cells. 2025 May 30. pii: 804. [Epub ahead of print]14(11):

Porphyromonas gingivalis-Lipopolysaccharide Induced Caspase-4 Dependent Noncanonical Inflammasome Activation Drives Alzheimer's Disease Pathologies.

Ambika Verma, Gohar Azhar, Pankaj Patyal, Xiaomin Zhang, Jeanne Y Wei.

  Chronic periodontitis, driven by the keystone pathogen Porphyromonas gingivalis, has been increasingly associated with Alzheimer's disease (AD) and AD-related dementias (ADRDs). However, the mechanisms through which P. gingivalis-lipopolysaccharide (LPS)-induced release of neuroinflammatory proteins contribute to the pathogenesis of AD and ADRD remain inadequately understood. Caspase-4, a critical mediator of neuroinflammation, plays a pivotal role in these processes following exposure to P. gingivalis-LPS. In this study, we investigated the mechanistic role of caspase-4 in P. gingivalis-LPS-induced IL-1β production, neuroinflammation, oxidative stress, and mitochondrial alterations in human neuronal and microglial cell lines. Silencing of caspase-4 significantly attenuated IL-1β secretion by inhibiting the activation of the caspase-4-NLRP3-caspase-1-gasdermin D inflammasome pathway, confirming its role in neuroinflammation. Moreover, caspase-4 silencing reduced the activation of amyloid precursor protein and presenilin-1, as well as the secretion of amyloid-β peptides, suggesting a role for caspase-4 in amyloidogenesis. Caspase-4 inhibition also restored the expression of key neuroinflammatory markers, such as total tau, VEGF, TGF, and IL-6, highlighting its central role in regulating neuroinflammatory processes. Furthermore, caspase-4 modulated oxidative stress by regulating reactive oxygen species production and reducing oxidative stress markers like inducible nitric oxide synthase and 4-hydroxynonenal. Additionally, caspase-4 influenced mitochondrial membrane potential, mitochondrial biogenesis, fission, fusion, mitochondrial respiration, and ATP production, all of which were impaired by P. gingivalis-LPS but restored with caspase-4 inhibition. These findings provide novel insights into the role of caspase-4 in P. gingivalis-LPS-induced neuroinflammation, oxidative stress, and mitochondrial dysfunction, demonstrating caspase-4 as a potential therapeutic target for neurodegenerative conditions associated with AD and related dementias.

Keywords:  Porphyromonas gingivalis; caspase-4; lipopolysaccharide; mitochondrial dysfunction; neuroinflammation; oxidative stress

DOI:  https://doi.org/10.3390/cells14110804
Int J Mol Sci. 2025 May 28. pii: 5181. [Epub ahead of print]26(11):

Effect of Microglial Activity on Gut Microbiota in Rats with Neuropathic Pain.

Seung-Wan Hong, Liyun Piao, Eun-Hwa Cho, Eun-Hye Seo, Seong-Hyop Kim.

  This study aimed to investigate the relationship between microglial activity and gut microbiota composition in a rat model of neuropathic pain (NP), and to evaluate how pregabalin treatment may influence these interrelated parameters. NP was simulated in rats via ligation and transection of the sciatic nerve. After confirming NP, the rats were randomly divided into treatment and control groups. Pregabalin (10 mg/kg) and the same dose of normal saline were administered to the treatment and control groups, respectively, on scheduled days. Microglial activity, cytokine levels, and the composition of the gut microbiota (assessed by the Firmicutes/Bacteroidetes (F/B) ratio) were evaluated. Pregabalin treatment significantly reduced microglial activity (which was notably lower in the treatment group than in the control group) and modulated pro-inflammatory and anti-inflammatory cytokine levels. While the F/B ratio in the control group significantly increased after NP surgery, the treatment group showed an initial increase followed by a notable decrease, approaching pre-surgery levels by day 28. This finding suggests that pregabalin treatment in rats with NP ameliorates microglial activity and is associated with a beneficial shift in the gut microbiota composition.

Keywords:  allodynia; brain–gut axis; microbiota; microglia; neuropathic pain; pregabalin

DOI:  https://doi.org/10.3390/ijms26115181
Int J Mol Sci. 2025 May 23. pii: 5050. [Epub ahead of print]26(11):

Ergolide Regulates Microglial Activation and Inflammatory-Mediated Dysfunction: A Role for the Cysteinyl Leukotriene Pathway.

Danielle M Galvin, Sara Fernandez-Garcia, Emma Dawson, Ciara Pryce, Billy P Egan, Niamh C Clarke, Alison L Reynolds, Derek A Costello.

  Neurodegenerative diseases are characterised by the progressive loss of neurons, leading to a decline in specific brain functions. Alzheimer's disease (AD) and Parkinson's disease (PD) are the most prevalent, affecting approximately 60 million people worldwide. The pathogenesis of these diseases is complex, combining inflammatory, oxidative, and excitotoxic processes that result in neuronal dysfunction and death. Despite recent advances, there is currently no cure for AD and PD. Available therapies demonstrate limited efficacy, highlighting the continuing need for novel therapeutic approaches. Ergolide, a naturally occurring sesquiterpene lactone from the Inula brittanica plant, has shown immunoregulatory properties in systemic immune cells and potential applications in certain cancers. This study examines whether the therapeutic effects of ergolide extend to the brain. We explored its mechanisms of action in vitro, and its capacity to restore behavioural integrity in zebrafish models of inflammation and neurotoxicity in vivo. We report the ability of ergolide to attenuate inflammatory cytokine and nitric oxide (NO) production from microglia in response to toll-like receptor activation. We further propose a role for the NFκB and cysteinyl leukotriene (CysLT) pathways in ergolide-mediated regulation of microglial activation. Ergolide did not protect against oxidative-induced neuronal death in vitro or mitigate seizure activity in zebrafish. Instead, we revealed a pro-oxidant and cytotoxic effect on neuroblastoma cells. Importantly, ergolide improved survival and alleviated the dysfunction in sensorimotor behaviour in a zebrafish model of inflammation. Our findings reveal a neuroprotective effect of ergolide, likely stemming from its immunoregulatory capacity. We also support further investigation of the CysLT pathway as a therapeutic target for neuroinflammatory-related disease.

Keywords:  NFκB; TLR; cytokines; microglia; nitric oxide; zebrafish larvae

DOI:  https://doi.org/10.3390/ijms26115050
Int Immunopharmacol. 2025 Jun 06. pii: S1567-5769(25)01024-0. [Epub ahead of print]161 115034

IRF8-Cathepsin S/PAR2 axis-mediated spinal microglia-neuron crosstalk is responsible for the exacerbation of postsurgical pain induced by preoperative stress.

Du-Juan Chen, Li Tang, Bin Chen, Si-Yin Fu, Miao-Jie Fan, Gao-Jie Chen, Yu-Ning Ou, Xiao-Zhi Wu, Fei Yang.

   BACKGROUND: Preoperative stress has been reported to be a risk factor for chronic postsurgical pain (CPSP), and spinal microglia might play a critical role in stress-induced chronification of postsurgical pain. However, the underlying molecular mechanism is still poorly understood.
METHODS: A mice model of single prolonged stress (SPS) combined with a plantar incision was used in the present study. The Von Frey test, the elevated plus maze test, and the open field test were applied to assess the pain- and anxiety-like behaviors. The effect of SPS and plantar incision, as well as the underlying mechanisms of CPSP, were determined by utilizing immunohistochemistry, immunofluorescence staining, and Western blotting.
RESULTS: In the present study, we demonstrated that previous SPS exposure resulted in anxiety-like behaviors and exacerbated postsurgical pain. Concomitantly, preoperative SPS promoted microglial activation, increased cathepsin S (CatS)-PAR2 signaling, and enhanced neuronal activation and the expression of synapse-associated proteins in the spinal dorsal horn of incisional mice. The immunofluorescence staining showed that the CatS was mainly co-expressed in microglia and PAR2 existed in neurons. Our behavioral pharmacology experiments confirmed that spinal microglia and CatS-PAR2 signaling played a critical role in the development of SPS-exacerbated postsurgical pain. By activating PAR2, intrathecal CatS administration was able to induce prolongation of postsurgical pain and enhanced spinal neuronal activation as well as the expression of synapse-associated proteins. We further found that the expression of IRF8 in the spinal cord of incisional mice was also enhanced by SPS. Genetic inhibition of IRF8 by intrathecal IRF8 siRNA injection significantly prevented SPS-exacerbated postsurgical pain. Furthermore, the increased microglial activation, upregulated CatS-PAR2 signaling, and enhanced neuronal activation along with increased synapse-associated proteins expression following SPS and incision were also dramatically suppressed by IRF8 siRNA.
CONCLUSIONS: Our data suggested that IRF8-CatS-PAR2 axis-mediated spinal microglia-neuron crosstalk is responsible for the exacerbation of postsurgical pain induced by preoperative stress.

Keywords:  Cathepsin S; Interferon regulatory factor 8; Microglia; Postsurgical pain; Protease-activated receptor-2; Single prolonged stress

DOI:  https://doi.org/10.1016/j.intimp.2025.115034
CNS Neurosci Ther. 2025 Jun;31(6): e70473

Pharmacological Inhibition of Mitochondrial Division Attenuates Simulated High-Altitude Exposure-Induced Memory Impairment in Mice: Involvement of Inhibition of Microglia-Mediated Synapse Elimination.

Panpan Chang, Mengqing Xu, Jiawei Zhu, Jiangpei Bian, Yapeng Lu, Qianqian Luo, Dan Wang, Li Zhu.

   AIM: To examine the protective effect of mitochondrial division inhibitor-1 (Mdivi-1) against high-altitude-induced memory impairment in mice.
METHODS: C57BL/6J male mice were administered Mdivi-1 before exposure to a simulated high-altitude hypoxia environment. The novel object recognition test and Morris water maze were used to test cognitive function. Golgi staining was used to visualize dendritic spines. PCR, Western blot, and immunofluorescence were performed to detect microglial activation and synaptic phagocytosis.
RESULTS: Mice exposed to short-term or long-term simulated high-altitude conditions experienced memory deficits. However, these deficits were significantly mitigated by pre-treatment with Mdivi-1. Simulated high-altitude exposure caused a reduction in synapses (dendritic spines) and the activation of microglia. Following Mdivi-1 injection, synapse density was significantly increased, and microglial activation was attenuated. Under hypoxic conditions, primary cultured microglia exhibited significantly enhanced phagocytic activity towards TRITC-Dextran or synaptosomes, which was abolished by Mdivi-1. Additionally, Mdivi-1 inhibited the HIF-1 signaling pathway and restricted the hypoxia-induced glycolytic activity in microglia. Specific inhibition of glycolysis effectively weakened the phagocytic capacity of microglia under hypoxia.
CONCLUSION: Mdivi-1 dramatically mitigated memory impairment in mice induced by simulated high-altitude exposure. Mdivi-1 reduced microglial glycolysis in hypoxic conditions, thereby limiting microglial activation and preventing excessive synaptic phagocytosis. Consequently, it effectively protected memory.

Keywords:  Mdivi‐1; high‐altitude exposure; memory impairment; microglia; phagocytosis of synapses

DOI:  https://doi.org/10.1111/cns.70473
Life Sci. 2025 Jun 08. pii: S0024-3205(25)00438-2. [Epub ahead of print] 123803

Metformin protects against insulin resistance-related dementia risk involving restored microglial homeostasis.

Nicolás González Pérez, Melina Bellotto, Soledad Porte Alcón, Melisa Bentivegna, Luciano Arcucci, Ángeles Vinuesa, Jessica Presa, Fernando Brites, Daniela Pérez Sirkin, Juan Beauquis, Flavia Saravia, Carlos Pomilio.

   AIMS: The rising prevalence of type 2 diabetes (T2D), obesity, and metabolic syndrome highlights the need for therapeutic strategies addressing both metabolic and neurological aspects of these conditions. This study evaluates the potential of metformin, a widely prescribed antidiabetic drug, to mitigate hippocampal changes induced by a moderate high-fat diet (HFD) and explores its mechanisms beyond glycemic regulation, including modulation of microglial autophagy, mitochondrial turnover, and neuroinflammation.
MATERIALS AND METHODS: We analyzed data from diabetic patients enrolled in the NACC study, a retrospective observational study, to assess cognitive outcomes associated with metformin use. Additionally, we examined the effects of metformin in HFD-treated mice, evaluating hippocampal insulin resistance, synaptic marker and microglial status. We also employed BV2 microglial cells exposed to palmitate as a lipotoxic stimulus to assess the potential of metformin in modulating microglial autophagy, mitochondrial status and inflammatory response.
KEY FINDINGS: In diabetic patients, metformin use is associated with improved memory and executive function, independent of cardiovascular risk factor control. In HFD-treated mice, metformin reduced hippocampal insulin resistance, increased synaptophysin levels, and reversed microglial activation and autophagy impairment. In BV2 microglial cells, metformin reduced IL-1β and TNFα expression, restored autophagic flux, and regulated mitochondrial turnover, leading to decreased mitochondrial ROS production.
SIGNIFICANCE: Our findings suggest that metformin exerts therapeutic effects beyond glycemic control in the context of T2D. By mitigating neuroinflammation and modulating microglial autophagy, metformin emerges as a promising therapeutic agent for cognitive decline associated with diabetes and potentially other neurological disorders.

Keywords:  Autophagy; Brain insulin resistance; High-fat diet; Microglia; Mitochondria; Neuroinflammation; Palmitate; Type 2 diabetes

DOI:  https://doi.org/10.1016/j.lfs.2025.123803
Acta Pharmacol Sin. 2025 Jun 11.

CD73 inhibitor AB680 suppresses glioblastoma in mice by inhibiting purine metabolism and promoting P2RY12+ microglia transformation.

Pan-Pan Gao, Hai-Feng Jiang, Yu-Wen Du, Ya Shu, Yu-Wei Wan, En-Zhi Yin, Jia-Xing Wu, Xin-Xin Liang, Si-Dao Wang, Ze-Hua Ding, Xiao-Hong Xu, Qi An, Cheng Miao, Xi-Miao He, Ming-Feng Li, Feng Liu, Xiao-Qian Chen.

  CD73 (ecto-5'-nucleotidase) is a metabolic immune checkpoint that dephosphorylates AMP to produce adenosine. Adenosine plays a pivotal role in immunosuppressive tumor microenvironment (TME) through adenosine receptors expressed on various immune cells. AB680, a specific CD73 inhibitor, is currently undergoing clinical trials for highly refractory cancers. In this study, we investigated the antitumor effects and mechanisms of AB680 in glioblastoma (GBM). By analyzing the expression pattern of CD73 across all cell types in orthotopic naïve G422TN-GBM tumors (d 7), we found that CD73 and its associated adenosine metabolic signaling were significantly elevated in G422TN-GBM cells compared to all other cell types. High CD73 expression was also observed in human GBM samples and was correlated with shorter patient survival. Administration of AB680 significantly prolonged survival in G422TN-GBM-bearing mice, reduced tumor size, cell proliferation, angiogenesis, and enhanced microglia activation and anti-tumor immune responses. Metabolomic analysis revealed that AB680 markedly increased ADP and AMP levels in the TME of orthotopic G422TN-GBM, thereby stimulating the activation of P2RY12+ microglia to exert their M1-like anti-cancer functions, as confirmed by human GBM scRNA-seq and G422TN-GBM snRNA-seq data. Furthermore, AB680 combined with RT/TMZ exhibited synergistic therapeutic effects by reversing RT/TMZ-induced increases in adenosine levels and promoting the transformation of P2RY12+ microglia. Overall, this study demonstrates that targeting CD73 with AB680 alters purine metabolism in the GBM microenvironment, promotes the transformation of P2RY12+ microglia, and triggers robust anti-tumor immune responses. These results support the rationale for AB680-based therapeutic clinical trials for GBM.

Keywords:  AB680; CD73; P2Y12 receptor; glioblastoma; microglia; purine metabolism

DOI:  https://doi.org/10.1038/s41401-025-01585-9
Biomaterials. 2025 Jun 07. pii: S0142-9612(25)00398-9. [Epub ahead of print]324 123479

Nasal-to-brain delivery of CCR5 antagonist for reshaping the dysregulated microglia-neuron axis and enhancing post-traumatic cognitive function.

Pengcheng Zhang, Yaxin Wang, Yigang Xu, Xueping Li, Xuya Yu, Yi Li, Dunwan Zhu, Fang Luo, Wen Li, Xu Jin.

  The dysregulation of the microglia-neuron axis plays a pivotal role in the pathogenesis of cognitive dysfunction following traumatic brain injury (TBI). The C-C chemokine receptor 5 (CCR5), markedly upregulated on both microglia and neurons post-injury, serves as a crucial mediator in the neuroinflammatory response and consequent neurological deficits. However, the therapeutic application of CCR5 antagonists in TBI is impeded by the delivery barriers presented by the blood-brain barrier (BBB) and their limited neuron-targeting efficacy. In this study, we introduce a novel nasal-to-brain delivery nanoplatform designed to facilitate the efficient brain delivery of DAPTA, a peptide antagonist of CCR5, aiming to inhibit CCR5 signaling and improving cognitive function following TBI. Biocompatible chitosan nanocarriers grafted with cell-penetrating peptide (TAT) and neuron-binding lactoferrin (Lf) were initially fabricated, demonstrating substantial DAPTA loading capacity, active mucosal and neural transportation, and enhanced neuron-targeting capabilities. The dual-engineered nanodrugs (DA@LT NPs) effectively penetrated the trigeminal and olfactory nerves, significantly enhancing the transport of DAPTA into the brain following intranasal delivery. In a TBI-induced mouse model, DA@LT NPs markedly alleviated the neuroinflammatory response, promoted M2 microglia polarization, protected neurons from pyroptosis, and improved both motor and cognitive functions of animals. The non-invasive intranasal delivery of the therapeutic CCR5 peptide antagonist using these mucus-penetrating and neuron-targeting nanoformulations presents a promising intervention for ameliorating neurological inflammation and cognitive impairments associated with TBI.

Keywords:  CCR5 antagonist; Cognitive dysfunction; Nasal-to-brain delivery; Traumatic brain injury

DOI:  https://doi.org/10.1016/j.biomaterials.2025.123479
Biomaterials. 2025 Jun 06. pii: S0142-9612(25)00397-7. [Epub ahead of print]324 123478

Electrode stimulation parameter modifications elicit differential glial cell responses in vitro over a short 4-h timecourse.

Christopher T Tsui, Soroush Mirkiani, David A Roszko, Matthew J Birtle, Anna E DeCorby, Matthew A Churchward, Vivian K Mushahwar, Kathryn G Todd.

  A cell culture model to assess glial cell responses to electrically stimulating electrodes in real-time was developed. Our previous work measured glial cell responses to stimulation paradigms and highlighted the importance of electrical stimulation considerations when designing a biocompatible neural interfacing device. The formation of voids around stimulating platinum-iridium electrodes also prompted an investigation into the fate of cells that would have once populated that area. Live-imaging experiments involving EGFP-positive microglia from heterozygous CX3CR-1+/EGFP mice were designed. Live-imaging animations over 4 h showed necrotic microglial cell death around stimulating electrodes. The degree to which this was occurring was further analyzed by electrically stimulating mixed glia and modifying parameters such as stimulation amplitude (0.1-0.4 mA), waveform shape (rectangular/sinusoidal/ramped), and frequency (25-55 Hz). The different stimulation parameters had differential effects on glial cell biomarker signal outputs (cell density, fluorescence intensity, area coverage). Scanning electron microscopy and energy-dispersive x-ray spectroscopy of the electrode surfaces post-stimulation did not reveal any significant damage or changes to surface elemental composition. Finally, electrochemical testing of the proposed in vitro setup revealed influences of different components of the mixed glial cell cultures towards the electrochemical performance of the electrodes in terms of cathodic charge storage capacity, impedance, phase angle, and voltage transient excursions. The results highlight the impact that electrical stimulation parameters have on glial cell fate at the electrode-cell culture interface, and provide data towards refinement of stimulation paradigms used in electrical neuromodulation applications.

Keywords:  Astrocyte; Electrical stimulation; Electrode; Glia; Microglia; Neuroinflammation

DOI:  https://doi.org/10.1016/j.biomaterials.2025.123478
Alzheimers Dement. 2025 Jun;21(6): e70344

Cerebrospinal fluid and brain positron emission tomography measures of synaptic vesicle glycoprotein 2A: Biomarkers of synaptic density in Alzheimer's disease.

Adam P Mecca, Nicholas J Ashton, Ming-Kai Chen, Ryan S O'Dell, Takaya Toyonaga, Wenzhen Zhao, Juan J Young, Elaheh Salardini, Kara A Bates, Jocelyn Ra, Sam Goodcase, Jason A Silva-Rudberg, Nabeel B Nabulsi, Ann Brinkmalm, Hlin Kvartsberg, Michael Schöll, Johanna Nilsson, Amy F T Arnsten, Yiyun Huang, Oskar Hansson, Henrik Zetterberg, Richard E Carson, Kaj Blennow, Christopher H van Dyck.

   INTRODUCTION: Positron emission tomography (PET) imaging with ligands for synaptic vesicle glycoprotein 2A (SV2A) has emerged as a promising methodology for measuring synaptic density in Alzheimer's disease (AD). We investigated associations between SV2A concentrations in the brain and cerebrospinal fluid (CSF).
METHODS: Twenty-one participants with early AD and 7 cognitively normal (CN) individuals underwent [11C]UCB-J PET. We used a novel enzyme-linked immunosorbent assay (ELISA) to measure CSF SV2A. Other synaptic and axonal proteins were also measured in CSF.
RESULTS: CSF SV2A was lower in AD compared to CN participants. Within the AD group, CSF SV2A was highly correlated with SV2A PET. By contrast, other CSF proteins were generally higher in participants with AD and not associated with SV2A PET.
DISCUSSION: We report a novel CSF assay for SV2A that is strongly correlated with the PET measurement of SV2A. Our results suggest that CSF SV2A may serve as a biomarker for synaptic density in AD.
HIGHLIGHTS: Synaptic vesicle glycoprotein 2A (SV2A) measured by a novel cerebrospinal fluid (CSF) enzyme-linked immunosorbent assay (ELISA) was lower in participants with symptomatic Alzheimer's disease (AD). CSF SV2A was highly correlated with SV2A measured by positron emission tomography (PET) in participants with AD. Other CSF synaptic/axonal proteins were not significantly associated with SV2A PET. CSF SV2A may serve as a biomarker for synaptic density in AD.

Keywords:  Alzheimer's disease; CSF; SV2A; biomarkers; synaptic density

DOI:  https://doi.org/10.1002/alz.70344