bims-microg 2025-09-14 papers

bims-microg

Biomed News

on Microglia in health and disease

Issue of 2025–09–14
thirty papers selected by
Marcus Karlstetter, Universität zu Köln

Microglia-astrocyte crosstalk regulates synapse remodeling via Wnt signaling.
Human myelinated brain organoids with integrated microglia as a model for myelin repair and remyelinating therapies.
Senescent-like border-associated macrophages regulate cognitive aging via migrasome-mediated induction of paracrine senescence in microglia.
Regulating PPARG Reduces Lipid Accumulation in Microglia and Promotes Functional Recovery After Spinal Cord Injury.
CD300f enables microglial damage sensing, efferocytosis, and apoptotic cell metabolization after brain injury.
Decoding NMDAR encephalitis: proteomic markers and computational identification of potential therapeutic pathways.
Microglia Drive Peripapillary Vascular Density Reduction in Normal Tension Glaucoma by Regulating the Rpl17/Stat5b/Apoa1 Axis.
Familial Alzheimer's disease mutation identifies novel role of SORLA in release of neurotrophic exosomes.
Temporal biphasic regulation of photoreceptor degeneration by microglial TREM2: A metabolic-immune nexus in retinitis pigmentosa.
Microglia-to-neuron signaling links APOE4 and inflammation to enhanced neuronal lipid metabolism and network activity.
Microglia contribute to bipolar depression through Serinc2-dependent phospholipid synthesis.
Hybridoma-inspired strategy crafts tailored multifunctional exosomes for precision therapy.
Sorting nexin 3 promotes ischemic retinopathy through RIP1- and RIP3-mediated myeloid cell necroptosis and mitochondrial fission.
The immune receptor SLAMF5 regulates myeloid-cell mediated neuroinflammation in multiple sclerosis.
Microglial deficiency in the ATRX chromatin remodeler elicits a viral mimicry immune response that impacts neuronal function and behavior.
Expression of intron-containing HIV-1 RNA induces NLRP1 inflammasome activation in myeloid cells.
Cyclin-dependent kinase inhibitor 1A mediates mouse line- and fate-dependent cellular responses in Cx3cr1-Cre genetic tools.
Coordination of autophagosome closure and release by the Alzheimer's disease-associated protein BIN1.
Targeting KCNN4 channels modulates microglial activation and apoptosis in a PD-relevant inflammatory model.
The critical role of matrix metalloproteinase 9-mediated microglial polarization in perioperative neurocognitive disorders of aged rats.
Stat3-mediated Th17 pathogenicity induced by periodontitis contributes to cognitive impairment by promoting microglial M1 polarization.
Type I interferons regulate nitric oxide production in Brucella abortus-activated microglia contributing to neuronal death.
A Semi-Automated and Unbiased Microglia Morphology Analysis Following Mild Traumatic Brain Injury in Rats.
The immunoregulator β-glucan produces antidepressant effects through microglia-mobilized astrocytic P2Y1R-BDNF signaling in the dentate gyrus.
Repopulating Microglia Suppress Peripheral Immune Cell Infiltration to Promote Poststroke Recovery.
Neuroprotective Effects of Transcranial Pulsed Current Stimulation: Modulation of Microglial Polarization in Traumatic Brain Injury.
Sex differences of synaptic plasticity and microglial remodeling in the dorsal hippocampus following trigeminal nerve injury in mice.
KLF7 Blocks MKNK2/HIF-1 Pathway-Mediated M1 Microglia Polarization to Ameliorate Ischemic Stroke-Induced Neurological Injury.
High-Throughput Cytokine Detection Platform for Evaluation of Chemical Induced Microglial Activation.
Miltirone attenuates post-ischemic stroke neuroinflammation and microglial lipid metabolism via regulating LBP and TLR4/NF-κB Axis.

Cell. 2025 Sep 10. pii: S0092-8674(25)00978-X. [Epub ahead of print]

Microglia-astrocyte crosstalk regulates synapse remodeling via Wnt signaling.

Travis E Faust, Yi-Han Lee, Ciara D O'Connor, Margaret A Boyle, Georgia Gunner, Violeta Durán-Laforet, Loris L Ferrari, Robert E Murphy, Ana Badimon, Kristina Sakers, Cagla Eroglu, Pinar Ayata, Anne Schaefer, Dorothy P Schafer.

  Astrocytes and microglia are emerging key regulators of activity-dependent synapse remodeling that engulf and remove synapses in response to changes in neural activity. Yet, the degree to which these cells communicate to coordinate this process remains an open question. Here, we use whisker removal in postnatal mice to induce activity-dependent synapse removal in the barrel cortex. We show that astrocytes do not engulf synapses in this paradigm. Instead, astrocytes reduce contact with synapses prior to microglia-mediated synapse engulfment. We further show that the reduced astrocyte-synapse contact is dependent on the release of Wnts from microglia downstream of neuron-to-microglia fractalkine ligand-receptor (CX3CL1-CX3CR1) signaling. These results demonstrate an activity-dependent mechanism by which microglia instruct astrocyte-synapse interactions, providing a permissive environment for microglia to remove synapses. We further show that this mechanism is critical to remodel synapses in a changing sensory environment and that this signaling is upregulated in several disease contexts.

Keywords:  Wnt; astrocyte; microglia; synapse remodeling

DOI:  https://doi.org/10.1016/j.cell.2025.08.023
Sci Transl Med. 2025 Sep 10. 17(815): eadp7047

Human myelinated brain organoids with integrated microglia as a model for myelin repair and remyelinating therapies.

Simona Lange, Martin Ebeling, Athéna Loye, Florian Wanke, Juliane Siebourg-Polster, Tania J J Sudharshan, Franziska Völlmy, Jakub Kralik, Bérengère Vidal, Kerstin Hahn, Lynette C Foo, Jan Hoeber.

Oligodendrocytes, the myelinating cells of the central nervous system (CNS), are essential for the formation of myelin sheaths and pivotal for maintaining axonal integrity and conduction. Disruption of these cells and the myelin sheaths they produce is a hallmark of demyelinating conditions like multiple sclerosis or those resulting from certain drug side effects, leading to profound neurological impairments. In this study, we created a human brain organoid comprising neurons, astrocytes, and myelinating oligodendrocytes. By integrating induced pluripotent stem cell-derived microglia, we endowed these myelinated human brain organoids (MHBOs) with immune characteristics. MHBOs with microglia (MHBOs +MG) enabled the investigation of demyelination and remyelination-a process in which myelin sheaths are regenerated-in a human context. After toxin-induced demyelination, we observed a reduction in myelin followed by subsequent self-driven remyelination. Proteomic and transcriptomic analyses provided a molecular signature of demyelination and myelin recovery indicating a central role for microglia in the remyelination process. Furthermore, the application of the pro-remyelinating compounds clemastine, XAV939, and BQ3020 further enhanced remyelination in MHBOs +MG but was ineffective in the absence of microglia. Cross-validation of our findings in mouse cerebellar slice cultures confirmed that the pro-remyelinating compounds were effective ex vivo, suggesting the translational potential of our MHBOs +MG model.

DOI: https://doi.org/10.1126/scitranslmed.adp7047
Nat Aging. 2025 Sep 10.

Senescent-like border-associated macrophages regulate cognitive aging via migrasome-mediated induction of paracrine senescence in microglia.

Mengyan Hu, Xinmei Kang, Zhiruo Liu, Shisi Wang, Sanxin Liu, Chunyi Li, Danli Lu, Qin Qin, Yuxin Liu, Haotong Yi, Liling Yuan, Quentin Liu, Zhengqi Lu, Wei Cai.

Aging is a major risk factor for various neurological disorders, including Alzheimer's disease, and is associated with the accumulation of senescent cells, which can themselves propagate the senescence process through paracrine signaling. Migrasomes are organelles that form during cellular migration, detach from parent cells and mediate intercellular communication. Here we demonstrate that border-associated macrophages (BAMs) acquire senescence-associated properties during early brain aging, possibly due to prolonged exposure to amyloid beta. Senescent-like BAMs show elevated production of migrasomes, which convey senescence-associated signals including the apoptosis inhibitor of macrophage to neighboring cells. We show that microglia are prominent recipients of senescent-like BAM-derived migrasomes, and that through activation of CD16 in recipient cells, the apoptosis inhibitor of macrophage inhibits apoptosis and promotes senescence induction. Blocking migrasome induction in senescent-like BAMs through treatment with Tspan4-targeting siRNA-encapsulated liposomes ameliorates cognitive deficits in aged mice. Our findings suggest that migrasomes are potent vehicles of senescence-regulatory signals and represent a promising target for senomorphic therapy.

DOI: https://doi.org/10.1038/s43587-025-00956-5
Adv Sci (Weinh). 2025 Sep 12. e06313

Regulating PPARG Reduces Lipid Accumulation in Microglia and Promotes Functional Recovery After Spinal Cord Injury.

Mingran Luo, Jiayun Liu, Yunxin Su, Tao Jiang, Xincan Wu, Peng Gao, Tao Qin, Mengyuan Wu, Qingqing Li, Shujun Zhang, Baorong He, Yongxiang Wang, Xiaodong Guo, Wei Zhou, Shujie Zhao, Jin Fan, Jian Chen, Guoyong Yin.

  Spinal cord injury (SCI) substantially affects functional capacity and the immune system plays a crucial role in recovery. Examining alterations in microglia metabolism can lead to improved repair mechanisms; however, the molecular subtyping of microglia lacks consensus. In this study, the effects of SCI on macrophages and microglia in mice are investigated to identify tailored therapeutic targets and interventions for patients with SCI. Macrophages infiltrate the spinal cord shortly after injury; however, infiltration decreases over time. Microglial phagocytosis of myelin debris is associated with increased lipid accumulation. Macrophage deletion improves outcomes, whereas microglial deletion worsens them. The PLIN2+ microglia subtype in lipid droplet formation shows abnormal activation of the Pparg signaling pathway compared with that with other subtypes. PPARG promotes lipid metabolism and recovery, and atorvastatin (a PPARG agonist) reverses altered metabolic processes. Macrophages and microglia play complex roles in SCI. Targeting PPARG and its agonists is a promising therapeutic approach for SCI.

Keywords:  PPARG; atorvastatin; lipid droplet; microglia; single‐cell sequencing; spinal cord injury

DOI:  https://doi.org/10.1002/advs.202506313
Brain Behav Immun. 2025 Sep 09. pii: S0889-1591(25)00347-2. [Epub ahead of print] 106105

CD300f enables microglial damage sensing, efferocytosis, and apoptotic cell metabolization after brain injury.

Luciana Negro-Demontel, Frances Evans, Andrés Cawen, Zachary Fitzpatrick, Hannah D Mason, Daniela Alí, Rubèn López-Vales, Natalia Lago, Hugo Peluffo.

  Microglia, the resident phagocytes of the central nervous system (CNS), continuously survey the parenchyma and its borders, acting as first responders to brain injury. Their ability to detect and react to environmental changes is mediated by a repertoire of surface receptors collectively known as themicroglial sensome. Here, we identify the lipid-sensing immunoreceptor CD300f as a key regulator of microglial responses to tissue damage and apoptotic cells. Using intravital two-photon microscopy, we show that CD300f-/- microglia fail to extend processes toward a laser-induced cortical lesion, indicating impaired detection of damage-associated cues. In models of mild traumatic brain injury (mTBI) and intracortical injection of apoptotic cells, CD300f deficiency led to reduced recognition and clearance of dying cells resulting in the accumulation of cellular debris within the parenchyma. At later stages, apoptotic remnants were retained within CD300f-/- microglia in vivo and bone marrow-derived macrophages in vitro, suggesting defective intracellular degradation. Proteomic analysis after a controlled cortical injury (CCI) contusion model revealed widespread dysregulation of autophagy-related and metabolic pathways, consistent with impaired efferocytosis and phagolysosomal processing. In parallel, we observed upregulation of the UDP-degrading ectonucleotidase ENTPD6 protein and downregulation of the microglial purinergic receptor P2ry6 mRNA, indicating a dysfunctional UDP-P2RY6 axis that may underlie impaired damage sensing and phagocytic initiation. Despite greater histological preservation, CD300f-/- mice exhibited worse long-term functional recovery after brain injury. Together, these findings position CD300f as a key damage-associated molecular pattern (DAMP) receptor that integrates purinergic signaling, efferocytosis, and metabolic adaptation, highlighting its essential role in coordinating microglial responses to CNS injury.

Keywords:  CD300f; CD300lf; DAMP; Efferocytosis; Microglia; Neuroinflammation; Phagocytosis; TBI

DOI:  https://doi.org/10.1016/j.bbi.2025.106105
Brain Behav Immun. 2025 Sep 08. pii: S0889-1591(25)00343-5. [Epub ahead of print] 106101

Decoding NMDAR encephalitis: proteomic markers and computational identification of potential therapeutic pathways.

Shengnan Wang, Yuhao Yuan, Xiaoqing Guo, Mengting Qin, Jiaojiao Chen, Dailiang Jiang, Yuhang Feng, Ling Mao.

   BACKGROUND: The proteome is a valuable resource for pinpointing therapeutic targets. Therefore, we conducted a proteome-wide Mendelian randomization (MR) study aimed at identifying potential protein markers and therapeutic targets for Anti-N-Methyl-D-Aspartate Receptor Encephalitis (NMDAR-E).
METHODS: Protein quantitative trait loci (pQTLs) were obtained from seven published genome-wide association studies (GWASs) focusing on the plasma proteome, resulting in summary-level data for 734 circulating protein markers. Genetic associations with NMDAR-E were determined via a large meta-analysis encompassing 323 cases and 1,519 controls. To confirm the causal roles of candidate proteins, we performed sequential colocalization. Subsequently, we experimentally validated prioritized proteins through two complementary approaches: (1) stimulation of HMC3 microglial cells with patient-derived anti-NMDAR-IgG versus control human IgG to assess antibody-induced protein expression dynamics; (2) Anti-NMDAR-IgG was stereotactically injected into the lateral ventricle of mice to establish the passive immunization NMDAR-E model, with comparative analysis of lateralized protein expression 7 days post-injection. Additionally, single cell-type expression analysis, protein-protein interaction (PPI) assessments, and evaluations of druggability were conducted to pinpoint enriched cell types and possible therapeutic targets.
RESULTS: In total, genetically predicted levels of 37 proteins showed associations with NMDAR-E risk. Elevated levels of three proteins (SIRPA, LGALS3, CASP3) and decreased levels of two proteins (TREM2, IL1RN) were correlated with an increased risk of NMDAR-E. The identified protein-coding genes were predominantly expressed in CD20+ B cells, with comparably elevated expression also observed in mast cells and CD16+ monocytes within the PBMCs of NMDAR-E patients. Anti-NMDAR-IgG induced upregulation of four proteins in human microglial cells and four laterally upregulated proteins in murine brains, with three overlapping responders. Furthermore, proteins TREM2, LGALS3, SIRPA, IL1RN and CASP3, which were initially targeted for drug development in cancer and autoimmune conditions, may also represent therapeutic options for NMDAR-E.
CONCLUSIONS: This study integrates genetic epidemiology with functional validation, successfully identifying protein biomarkers associated with NMDAR-E risk. The convergence of MR-predicted causal proteins with antibody-driven expression changes in human microglia and mouse models underscores their pathological relevance, providing actionable insights for biomarker screening and therapeutic development.

Keywords:  Anti-N-methyl-D-aspartate receptor encephalitis; Biomarker; Drug target; Protein; Proteome-wide Mendelian randomization; Single-cell transcriptome

DOI:  https://doi.org/10.1016/j.bbi.2025.106101
Adv Sci (Weinh). 2025 Sep 08. e07894

Microglia Drive Peripapillary Vascular Density Reduction in Normal Tension Glaucoma by Regulating the Rpl17/Stat5b/Apoa1 Axis.

Di Zhang, Sisi Chen, Yanfeng Zhang, Leyi Qiu, Mengxian Du, Wulian Song, Fengyi Guo, Jingyang Zhang, Xinna Liu, Huiping Yuan.

  Normal tension glaucoma (NTG) is a predominant subset of glaucoma in Asia and is characterized by glaucomatous optic neuropathy in the absence of elevated intraocular pressure. Alterations in retinal blood vessels are reported to be important mechanisms of glaucomatous optic nerve damage. Retinal peripapillary vascular density is assessed in patients with early stage NTG and OPTN (E50K) mutant mice and confirmed a similar reduction in retinal peripapillary vascular density in patients with NTG and model mice. Thus, identifying the mechanisms underlying retinal vascular changes in NTG is crucial for developing effective therapeutic strategies. This study revealed that Rpl17 is upregulated in the retinal microglia of OPTN (E50K) mutant mice. Rpl17 exerts regulatory control over Apoa1 by directly interacting with Stat5b, which causes damage to retinal vascular endothelial cells and leads to a reduction in retinal peripapillary vascular density. Additionally, we identified ellagic acid (EA) as an Apoa1 antagonist that is able to alleviate damage to retinal vascular endothelial cells and increase retinal peripapillary vascular density, which subsequently protected retinal ganglion cells and improved visual function. The work elucidates the vascular mechanism of NTG optic nerve damage and proposes EA as an effective adjuvant therapy strategy.

Keywords:  microglia; neuroprotection; normal tension glaucoma; retinal peripapillary vascular density

DOI:  https://doi.org/10.1002/advs.202507894
Alzheimers Dement. 2025 Sep;21(9): e70591

Familial Alzheimer's disease mutation identifies novel role of SORLA in release of neurotrophic exosomes.

Kristian Juul-Madsen, Ina-Maria Rudolph, Jemila P Gomes, Katrina Meyer, Peter L Ovesen, Malgorzata Gorniak-Walas, Marianna Kokoli, Narasimha S Telugu, Malthe von Tangen Sivertsen, Fabia Febbraro, Duncan S Sutherland, Johan Palmfeldt, Sebastian Diecke, Olav M Andersen, Matthias Selbach, Thomas E Willnow.

   INTRODUCTION: Mutations in SORL1, encoding the sorting receptor Sortilin-related receptor with A-type repeats (SORLA), are found in individuals with Alzheimer's disease (AD). We studied SORLAN1358S, carrying a mutation in its ligand binding domain, to learn more about receptor functions relevant for human brain health.
METHODS: We investigated consequences of SORLAN1358S expression in induced pluripotent stem cell (iPSC)-derived human neurons and microglia, using unbiased proteome screens and functional cell assays.
RESULTS: We identified alterations in the SORLAN1358S interactome linked to biogenesis of exosomes. Consequently, the mutant receptor failed to promote release and neurotrophic qualities of exosomes, a defect attributed to altered exosomal content of microRNAs controlling neuronal maturation.
DISCUSSION: We identified a role for SORLA in controlling quantity and neurotrophic quality of exosomes secreted by cells, suggesting impaired cellular cross talk through exosomes as a pathological trait contributing to AD pathology in carriers of SORL1 variants.
HIGHLIGHTS: Familial Alzheimer's disease mutation in SORL1 changes interactome of mutant Sortilin-related receptor with A-type repeats (SORLA). Mutant SORLA impairs release of exosomes from neurons and microglia. Mutant exosomes lack neurotrophic qualities. Defect linked to alterations in microRNA content.

Keywords:  Alzheimer's disease; exosomes; iPSC models; microglia; multi‐omics

DOI:  https://doi.org/10.1002/alz.70591
Sci Adv. 2025 Sep 12. 11(37): eadw9299

Temporal biphasic regulation of photoreceptor degeneration by microglial TREM2: A metabolic-immune nexus in retinitis pigmentosa.

Rong Li, Jing Zhang, Jiang-Mei Wu, Jun-Qi Fan, Bin Lin.

Retinitis pigmentosa (RP), the leading cause of inherited blindness, lacks therapies because of undefined photoreceptor degeneration mechanisms. While microglia/myeloid cells drive RP progression, their phenotype-regulating determinants remain unclear. Using rd10 mice, we reveal TREM2 as a biphasic RP regulator via STAT2-mediated microglial reprogramming. Early TREM2 loss amplifies neuroinflammation through STAT2 hyperactivation, while late deficiency triggers NF-κB/STAT2-driven microglial apoptosis, impairing phagocytosis yet preserving photoreceptors. We uncover a photoreceptor-microglia metabolic axis where apoptotic photoreceptors release arachidonic acid, salicylic acid, and creatinine to induce STAT2-dependent apoptosis in TREM2-deficient cells. Crucially, we identify intermicroglia PSAP/GPR37 signaling as a self-propagating apoptotic mechanism-the first evidence of apoptotic transmission in retinal degeneration. This study establishes three advances: (i) TREM2 exhibits stage-dependent neuroprotective/neurotoxic roles, (ii) photoreceptor metabolites dictate microglia/myeloid cell fate via STAT2, and (iii) microglial apoptosis spreads through membrane signaling complexes. Our findings redefine neuroimmune dynamics in retinal degeneration, propose chronotherapeutic TREM2 targeting, and extend to Alzheimer's and other microglia-associated CNS disorders via metabolic-immune interplay.

DOI: https://doi.org/10.1126/sciadv.adw9299
Proc Natl Acad Sci U S A. 2025 Sep 16. 122(37): e2516103122

Microglia-to-neuron signaling links APOE4 and inflammation to enhanced neuronal lipid metabolism and network activity.

Ana P Verduzco Espinoza, Na Na, Loraine Campanati, Priscilla Ngo, Kristin K Baldwin, Hollis T Cline.

  Microglia regulate neuronal circuit plasticity. Disrupting their homeostatic function has detrimental effects on neuronal circuit health. Neuroinflammation contributes to the onset and progression of neurodegenerative diseases, including Alzheimer's disease (AD), with several microglial activation genes linked to increased risk for these conditions. Inflammatory microglia alter neuronal excitability, inducing metabolic strain. Interestingly, expression of APOE4, the strongest genetic risk factor for AD, affects both microglial activation and neuronal excitability, highlighting the interplay between lipid metabolism, inflammation, and neuronal function. It remains unclear how microglial inflammatory state is conveyed to neurons to affect circuit function and whether APOE4 expression alters this intercellular communication. Here, we use a reductionist model of human iPSC-derived microglial and neuronal monocultures to dissect how the APOE genotype in each cell type independently contributes to microglial regulation of neuronal activity during inflammation. Conditioned media (CM) from LPS-stimulated microglia increased neuronal network activity, assessed by calcium imaging, with APOE4 microglial CM driving greater neuronal activity than APOE3 CM. Both APOE3 and APOE4 neurons increase network activity in response to CM treatments, while APOE4 neurons uniquely increase presynaptic puncta in response to APOE4 microglial CM. CM-derived exosomes from LPS-stimulated microglia can mediate increases to network activity. Finally, increased network activity is accompanied by increased lipid droplet (LD) metabolism, and blocking LD metabolism abolishes network activity. These findings illuminate how microglia-to-neuron communication drives inflammation-induced changes in neuronal circuit function, demonstrate a role for neuronal LDs in network activity, and support a potential mechanism through which APOE4 increases neuronal excitability.

Keywords:  APOE4; Alzheimer’s disease; exosomes; lipid droplets; microglia

DOI:  https://doi.org/10.1073/pnas.2516103122
Proc Natl Acad Sci U S A. 2025 Sep 16. 122(37): e2500116122

Microglia contribute to bipolar depression through Serinc2-dependent phospholipid synthesis.

Ying-Han Wang, Chong-Lei Fu, Lin-Bo Chen, Chu-Yi Zhang, Jian-Shan Chen, Qiao-Ming Zhang, Yirui Liang, Rui-Lan Yang, Yu Li, Ya-Ni Zhang, Yi-Nuo Han, Zhen-Liang Yuan, Yi-Ni Chen, Haimei Li, Yanmeng Pan, Shaohua Hu, Ming Li, Li-Ping Cao, Jun Yao.

  Although clinical research has revealed microglia-related inflammatory and immune responses in bipolar disorder (BD) patient brains, it remains unclear how microglia contribute to the pathogenesis of BD. Here, we demonstrated that Serinc2 is associated with susceptibility to BD and showed a reduced expression in BDII patient plasma, which correlated with the disease severity. Using induced pluripotent stem cell (iPSC) models of sporadic and familial BDII patients, we found that Serinc2 expression showed deficits in iPSC-derived microglia-like cells, resulting in decreased synaptic pruning. Further, combining the microglia-specific Serinc2-deficient mouse and iPSC-microglia models, we found that microglial Serinc2 deficits functioned through attenuating the synthesis of serine-related phospholipids in the plasma membrane, thus resulting in depression-like behavioral abnormalities in the animals. Finally, we showed that the Serinc2-dependent lipid deficits diminished microglial membrane CR3 formation to interrupted synaptic pruning signals from neurons. Therefore, our results indicated that Serinc2 deficits in microglia might contribute to the pathogenesis of BD.

Keywords:  Serinc2; bipolar disorder; induced pluripotent stem cell; mental disorder; microglia

DOI:  https://doi.org/10.1073/pnas.2500116122
Proc Natl Acad Sci U S A. 2025 Sep 16. 122(37): e2424547122

Hybridoma-inspired strategy crafts tailored multifunctional exosomes for precision therapy.

Zhufeng Dong, Tieying Yin, Zhiqin Deng, Hang Zou, Lei Kuang, Yang Wang, Wen Shi, Mengwei Han, Siqing Zhu, Zheng Wang, Xiaoye Hu, Yazhou Z Wang.

  Engineering functional exosomes represents a cutting-edge approach in biomedicine, holding the promise to transform targeted therapy. However, challenges such as achieving consistent modification and scalability have limited their wider adoption. Herein, we introduce a universal and effective strategy for engineering multifunctional exosomes through cell fusion. The hybrid-cell-derived exosomes could combine the functional properties of both parental cells and be readily produced by passaging. This method enables customization and large-scale production of exosomes with specific functionalities, potentially advancing precision therapies across a wide array of diseases. As demonstrated in Alzheimer's disease (AD) models, exosomes derived from hybrid cells (HCs) (H/Exos) of mesenchymal stem cells (MSCs) and neutrophils efficiently targeted AD-affected areas via LFA-1/ICAM-1 and improved the cognition of AD mice. Beyond directly promoting neural repair and inhibiting inflammation, we surprisingly found that H/Exos increased microglia abundance, modulated microglia gene expression, enhanced the endocytic and lysosomal function, and promoted microglial phagocytic phenotypic differentiation to clear Aβ. This hybridoma-inspired strategy offers a versatile and practical way to engineer exosomes with desired therapeutic functions, representing a promising direction for personalized therapies.

Keywords:  Alzheimer’s disease; hybrid cells; mesenchymal stem cells; microglial differentiation; target therapeutic exosomes

DOI:  https://doi.org/10.1073/pnas.2424547122
Proc Natl Acad Sci U S A. 2025 Sep 16. 122(37): e2426578122

Sorting nexin 3 promotes ischemic retinopathy through RIP1- and RIP3-mediated myeloid cell necroptosis and mitochondrial fission.

Jiaojiao Wang, Chunhong Zhou, Kai Zhuang, Jiami Zou, Wanlu Qiu, Mei Jin, Weile Ye, Pinglian Yang, Zhihua Zheng, Qing Zhou, Zunnan Huang, Yuanxiang Wang, Peiqing Liu, Jing Lu, Yuqing Huo, Zhiping Liu.

  Proliferative retinopathy is a leading cause of irreversible blindness in humans; however, the molecular mechanisms behind the immune cell-mediated retinal angiogenesis remain poorly elucidated. Here, using single-cell RNA sequencing in an oxygen-induced retinopathy (OIR) model, we identified an enrichment of sorting nexin (SNX)-related pathways, with SNX3, a member of the SNX family that is involved in endosomal sorting and trafficking, being significantly upregulated in the myeloid cell subpopulations of OIR retinas. Immunostaining showed that SNX3 expression is markedly increased in the retinal microglia/macrophages of mice with OIR, which is mainly located within and around the neovascular tufts. Myeloid cell-specific deficiency of Snx3 inhibited retinal neovascularization, hyperpermeability, and dysfunction in OIR mice. Using glutathione S-transferase pull-down, coimmunoprecipitation, and immunofluorescent staining, we found that SNX3 interacted with receptor-interacting protein 1/3 (RIP1 and RIP3). We further demonstrated that RIP1/3 degradation was accelerated in SNX3-deleted microglia/macrophages, causing an inhibition of hypoxia-induced necroptosis and mitochondrial fission, thereby decreasing the production of proinflammatory and proangiogenic factors (FGF2 and MMP12). Moreover, OIR retinas from myeloid cell-specific SNX3 overexpression transgenic mice presented more angiogenic tufts, while RIP1/3 inhibition largely ablated SNX3 overexpression-induced pathological angiogenesis. Based on the structure of SNX3, we identified a small-molecule inhibitor, W1122. Intriguingly, we found that W1122 effectively inhibited retinal angiogenesis in the OIR model, and combination treatment with anti-Vascular Endothelial Growth Factor (VEGF) yielded enhanced antiangiogenic effects. Collectively, our findings disclose a link between SNX3 and RIP1/3 signaling and implicate SNX3 in the development of ischemic retinopathy.

Keywords:  macrophage; microglia; necroptosis; retinal angiogenesis; retinopathy

DOI:  https://doi.org/10.1073/pnas.2426578122
PLoS Biol. 2025 Sep;23(9): e3003373

The immune receptor SLAMF5 regulates myeloid-cell mediated neuroinflammation in multiple sclerosis.

Laura Bellassen, Keren David, Bar Lampert, Avital Sarusi-Portuguez, Michael Tsoory, Jazz Lubliner, Eran Hornstein, Michael Osherov, Ron Milo, Ori Brenner, Shirly Becker-Herman, Idit Shachar.

Multiple sclerosis (MS) is a chronic neurological disorder characterized by demyelination of the central nervous system (CNS), leading to a broad spectrum of physical and cognitive impairments. Myeloid cells within the CNS, including microglia and border-associated macrophages, play a central role in the neuroinflammatory processes associated with MS. Activation of these cells contributes to the local inflammatory response and promotes the recruitment of additional immune cells into the CNS. SLAMF5 is a cell surface receptor that functions as a homophilic adhesion molecule, capable of modulating immune cell activity through both activating and inhibitory signals. In this study, we investigated the expression and function of SLAMF5 in CNS-resident and peripheral myeloid cells using the murine model of MS, experimental autoimmune encephalomyelitis (EAE). Our findings demonstrate that both total and brain-specific SLAMF5 deficiency in myeloid cells leads to decreased expression of activation and costimulatory molecules, including MHC class II (MHCII) and CD80. This downregulation is mediated, at least in part, through the transcription factor BHLHE40 and its regulation of CD52, resulting in delayed onset and reduced progression of the disease. Furthermore, pharmacological blockade of SLAMF5 in the brain halted disease progression and reduced the expression of myeloid activation markers. In human studies, SLAMF5 blockade in peripheral monocytes from MS patients and in induced pluripotent stem cell (iPSC)-derived microglia reduced the expression of HLA-DR, CD80, and CD52. Together, these results identify SLAMF5 as a key regulator of myeloid cell activation in neuroinflammation and suggest that it may represent a promising therapeutic target for autoimmune disorders such as MS.

DOI: https://doi.org/10.1371/journal.pbio.3003373
PLoS Biol. 2025 Sep 12. 23(9): e3002659

Microglial deficiency in the ATRX chromatin remodeler elicits a viral mimicry immune response that impacts neuronal function and behavior.

Sarfraz Shafiq, Alireza Ghahramani, Kasha Mansour, Miguel Pena-Ortiz, Julia K Sunstrum, Milica Pavlovic, Yan Jiang, Megan E Rowland, Wataru Inoue, Nathalie G Bérubé.

The importance of chromatin-mediated processes in neurodevelopmental and intellectual disability disorders is well recognized. However, how chromatin dysregulation in glial cells impacts cognitive abilities is less well understood. Here, we demonstrate that targeted loss of the ATRX chromatin remodeler targeted to microglia leads to altered cell morphology, increased chromatin accessibility profiles, and de-repression of endogenous retroelements, triggering viral mimicry. In mice that lack ATRX in microglia, CA1 hippocampal neuron morphology and electrophysiological properties are affected, and the mice display specific behavioral deficits. These findings demonstrate that ATRX is required in microglia to preserve chromatin structure and maintain microglial homeostasis. Disruption of these functions elicits neuroinflammation and may contribute to the pathology of human neurological disorders caused by ATRX mutations.

DOI: https://doi.org/10.1371/journal.pbio.3002659
PLoS Biol. 2025 Sep;23(9): e3003320

Expression of intron-containing HIV-1 RNA induces NLRP1 inflammasome activation in myeloid cells.

Sallieu Jalloh, Ivy K Hughes, Hisashi Akiyama, Aldana D Gojanovich, Andres A Quiñones-Molina, Mengwei Yang, Andrew J Henderson, Gustavo Mostoslavsky, Suryaram Gummuluru.

Despite the success of antiretroviral therapy in suppressing plasma viremia in people living with human immunodeficiency virus type-1 (HIV-1), persistent viral RNA expression in tissue reservoirs is observed and can contribute to HIV-1-induced immunopathology and comorbidities. Infection of long-lived innate immune cells, such as tissue-resident macrophages and microglia may contribute to persistent viral RNA production and chronic inflammation. We recently reported that de novo cytoplasmic expression of HIV-1 intron-containing RNA (icRNA) in macrophages and microglia leads to MDA5 and MAVS-dependent innate immune sensing and induction of type I IFN responses, demonstrating that HIV icRNA is a pathogen-associated molecular pattern (PAMP). In this report, we show that cytoplasmic expression of HIV-1 icRNA also induces NLRP1 inflammasome activation and IL-1β secretion in macrophages and microglia in an RLR- and endosomal TLR-independent manner. Infection of both macrophages and microglia with either replication-competent or single-cycle HIV-1 induced IL-1β secretion, which was attenuated when cytoplasmic expression of viral icRNA was prevented. While IL-1β secretion was blocked by treatment with caspase-1 inhibitors or knockdown of NLRP1 or caspase-1 expression in HIV-infected macrophages, overexpression of NLRP1 significantly enhanced IL-1β secretion in an HIV-icRNA-dependent manner. Immunoprecipitation analysis revealed interaction of HIV-1 icRNA, but not multiply-spliced HIV-1 RNA, with NLRP1, suggesting that HIV-1 icRNA sensing by NLRP1 is sufficient to trigger inflammasome activation. Together, these findings reveal a pathway of NLRP1 inflammasome activation induced by de novo expressed HIV icRNA in HIV-infected myeloid cells.

DOI: https://doi.org/10.1371/journal.pbio.3003320
Cell Rep. 2025 Sep 09. pii: S2211-1247(25)01038-1. [Epub ahead of print]44(9): 116267

Cyclin-dependent kinase inhibitor 1A mediates mouse line- and fate-dependent cellular responses in Cx3cr1-Cre genetic tools.

Ayato Yamasaki, Hayato Shintaku, Akihito Harada, Kazumitsu Maehara, Kaori Tanaka, Mai Saeki, Minako Ito, Hiroyuki Konishi, Makoto Tsuda, Marco Prinz, Yusuke Kishi, Yasuyuki Ohkawa, Shota Yamamoto, Takahiro Masuda.

  Microglia, the resident macrophages in the central nervous system (CNS), have been intensively studied using rodent genetic models, including the Cre-loxP system. Among them are tamoxifen (TAM)-inducible CX3C chemokine receptor 1 (Cx3cr1)-Cre mouse lines (Cx3cr1CreERT2), which have enabled in-depth analyses of the biological features and functions of myeloid cells, including microglia. Occasionally, these Cx3cr1CreERT2 tools have yielded conflicting biological outcomes, the underlying mechanism of which remains unclear. Here, we comparatively characterized the two available Cx3cr1CreERT2 lines (Cx3cr1CreERT2(Litt) and Cx3cr1CreERT2(Jung)). We find a mouse line-specific and TAM-dependent persistent induction of cyclin-dependent kinase inhibitor 1A (CDKN1A, also known as p21) in microglia of Cx3cr1CreERT2(Litt) mice, but not in those of Cx3cr1CreERT2(Jung) mice, which affects experimental readouts with altered proliferative capacity. Furthermore, aberrant cellular alterations observed in postnatal Cx3cr1CreERT2(Litt) microglia are mitigated by a functional inhibition of CDKN1A. Together, these findings underscore the significance of mouse line-specific phenomena that alter microglial outcomes in a CDKN1A-dependent manner.

Keywords:  CP: Cell biology; CP: Neuroscience; Cdkn1a; Cre line; microglia; proliferation

DOI:  https://doi.org/10.1016/j.celrep.2025.116267
Cell Rep. 2025 Sep 09. pii: S2211-1247(25)01037-X. [Epub ahead of print]44(9): 116266

Coordination of autophagosome closure and release by the Alzheimer's disease-associated protein BIN1.

Jennifer E Palmer, Claudia Puri, Ryan S O'Rourke, Sung Min Son, Chun Sang, Yu-Wen Alvin Huang, David C Rubinsztein.

  Autophagosome closure by the endosomal sorting complex required for transport (ESCRT) complex is a prerequisite for their dynamin 2 (DNM2)-dependent release from the recycling endosome and subsequent lysosomal clearance. However, the mechanism that coordinates autophagosome closure and release is unknown. We identified that the Alzheimer's disease-associated protein bridging integrator 1 (BIN1) is a critical mediator of this coordination. Prior to autophagosome closure, BIN1 is held at autophagosomes by ESCRT-III and inhibits DNM2. Once the autophagosome has closed and ESCRT-III disassembles, BIN1 is released, removing the inhibition of DNM2. This mechanism provides insight into the functional consequences of increased BIN1 expression, as this occurs in microglia with Alzheimer's disease risk-associated polymorphisms. We find that the overexpression of BIN1 microglial isoforms inhibits DNM2-mediated autophagosome release and autophagic clearance. This provides a coherent explanation for the increased Alzheimer's disease risk associated with BIN1, as impaired microglial autophagy alters phagocytosis and is associated with microglial senescence and neuroinflammation.

Keywords:  Alzheimer’s disease; BIN1; CP: Cell biology; CP: Neuroscience; DNM2; ESCRT-III; autophagy; microglia

DOI:  https://doi.org/10.1016/j.celrep.2025.116266
Biomed Pharmacother. 2025 Sep 05. pii: S0753-3322(25)00720-6. [Epub ahead of print]191 118526

Targeting KCNN4 channels modulates microglial activation and apoptosis in a PD-relevant inflammatory model.

Hao-Yuan Hung, I-Hsun Li, Yung-Ni Lin, Ting-Yin Yeh, Ke-Xin Ng, Tin-An Wang, Kun-Ting Hong, Teng-Hui Wang, Yi-Chieh Wu, Jui-Hu Shih.

  Parkinson's disease (PD) is characterized by chronic neuroinflammation and progressive dopaminergic neurodegeneration, driven primarily by the activation of microglia and associated apoptotic pathways. The intermediate-conductance calcium-activated potassium channel KCNN4 has recently emerged as a potential therapeutic target, yet its role in chronic neurodegenerative conditions remains underexplored. In this study, we investigated whether pharmacological inhibition of KCNN4 using TRAM-34 can modulate both inflammatory and apoptotic responses in an LPS-induced mouse model of PD. Our in vivo findings demonstrate that TRAM-34 suppressed microglial activation, evidenced by reduced COX-2 and lower TLR4 relative to LPS, together with attenuated IL-1β; striatal Iba1 morphology at Day 86 also indicated mitigated activation. Furthermore, TRAM-34 treatment preserved dopaminergic neurons, as shown by increased tyrosine hydroxylase immunoreactivity, and mitigated apoptotic signaling by decreasing phosphorylated p53, cytochrome c release, and cleaved PARP-1 levels. Importantly, [¹ ⁸F]FE-PE2I PET at Day 30 showed partial restoration of striatal DAT, aligning with the Day-86 immunohistochemistry. In parallel, behavioral assessments using the rotarod test demonstrated that TRAM-34 significantly ameliorated LPS-induced motor deficits, further supporting its functional neuroprotective effects. In vitro studies further revealed that KCNN4 inhibition attenuates microglial overactivation and suppresses downstream inflammatory and pro-apoptotic signaling pathways. These dual effects suggest that TRAM-34 attenuates PD progression by simultaneously targeting neuroinflammation and apoptosis. This study underscores the therapeutic potential of KCNN4 channel inhibition in modulating microglial function and preventing neuronal loss in PD. By bridging molecular mechanisms with translational outcomes, our findings pave the way for KCNN4-targeted strategies to mitigate neurodegeneration and improve patient outcomes in PD.

Keywords:  Apoptosis; KCNN4 channel; Microglia; Neuroinflammation; Parkinson’s disease

DOI:  https://doi.org/10.1016/j.biopha.2025.118526
Front Immunol. 2025 ;16 1650254

The critical role of matrix metalloproteinase 9-mediated microglial polarization in perioperative neurocognitive disorders of aged rats.

Xi Xin, Haonan Zhang, Chenyi Yang, Xinyi Wang, Lin Zhang, Ji Ma, Haiyun Wang.

   Background: Perioperative neurocognitive disorders (PND) is a significant clinical syndrome and neuroinflammation is an important pathological process. Matrix metalloproteinase 9 (MMP9) as a Zn2+-dependent matrix enzyme, not only maintains the integrity of the blood-brain barrier and synaptic plasticity, but also plays a key regulatory factor in peripheral and central nervous inflammation. This study aimed to investigate the effects of MMP9-mediated microglial polarization on surgery-induced neuroinflammation in aged rats and to provide novel targets for prevention and treatment of PND.
Methods: This study utilized an intraperitoneal injection of SB-3CT, an MMP9 inhibitor, to impede the action of MMP9. Morris water maze and novel object recognition test were conducted to assess behavioral performances. Western blot was employed to examine hippocampal inflammatory factors. Immunofuorescence and flow cytometry were used to examine the transformation of microglia phenotype.
Results: The findings demonstrated that surgical intervention induced significant impairment in learning and memory performance in aged rats, accompanied by elevated MMP9 expression, exacerbated hippocampal inflammation, and microglial polarization characterized by a predominant M1 phenotype. Administration of SB-3CT effectively reversed these pathological manifestations.
Conclusion: The inhibition of MMP9 can enhance neurological function by modulating the polarization of microglia and alleviating neuroinflammation, which is a new approach for perioperative neuroprotection in high-risk PND patients.

Keywords:  aged; matrix metalloproteinase 9; microglia; neuroinflammation; perioperative neurocognitive disorders

DOI:  https://doi.org/10.3389/fimmu.2025.1650254
Front Immunol. 2025 ;16 1590665

Stat3-mediated Th17 pathogenicity induced by periodontitis contributes to cognitive impairment by promoting microglial M1 polarization.

Yining Zhou, Xinyi Xie, Huiwen Chen, Lina Xu, Che Qiu, Hui Shen, Wei Zhou, Zhongchen Song.

   Introduction: Periodontitis has been identified as a potential risk factor for cognitive impairment associated with immune dysregulation. T helper 17 (Th17) cell-associated immune responses are involved in both diseases, while signal transducer and activator of transcription 3 (Stat3) is kown to be crucial for Th17 pathogenicity. Accordingly, in this study, we investigated how Stat3-mediated Th17 pathogenicity contributes to the link between periodontitis and cognitive impairment.
Methods: Levels of Th17-related cytokines in gingival crevicular fluid (GCF) were measured in individuals with and without cognitive impairment. A periodontitis model was established in mice with conditional deletion of Stat3 in Th17 cells (Stat3 fl/fl; Il17a-CreERT2, cKO) and wild type (Stat3 fl/fl, WT) mice via injection of Porphyromonas gingivalis lipopolysaccharide (P. gingivalis LPS) into gingival sulcus. Cognitive function was assessed through behavioral tests. Expression of Th17-related cytokines and microglial pro-inflammatory markers was evaluated by reverse transcription-quantitative PCR (RT-qPCR), ELISA, flow cytometry, and immunohistochemistry. To evaluate effects of CD4+ T cells on microglial M1 polarization, BV2 microglia were co-cultured with primary CD4+T cells which were stimulated with P. gingivalis LPS after isolated from cKO and WT mice.
Results: Compared with cognitively normal participants, levels of Th17-related cytokines increased in participants with cognitive impairment. Significant alveolar bone resorption and cognitive impairment were observed in WT mice with periodontitis. These periodontitis-induced changes were alleviated in cKO mice, accompanied by a weakening of neuroinflammation and mitigation of Th17 immune responses. In vitro, M1 polarization and activation of the MAPK/ERK signaling pathway were inhibited in BV2 cells co-cultured with Stat3-deleted Th17 cells.
Conclusion: Stat3-mediated Th17 pathogenicity bridged the correlation between periodontitis and neuroinflammation related to cognitive impairment, offering novel perspectives for a therapeutic target for blocking the mouth-to-brain axis.

Keywords:  Stat3; Th17 cells; cognitive impairment; microglia; neuroinflammation; periodontitis

DOI:  https://doi.org/10.3389/fimmu.2025.1590665
Front Immunol. 2025 ;16 1661395

Type I interferons regulate nitric oxide production in Brucella abortus-activated microglia contributing to neuronal death.

Julia Rodríguez, Alex D Guano, Ignacio Mazzitelli, Vida A Dennis, Ana M Rodríguez, Guillermo H Giambartolomei.

  Microglia have a central role in the immunopathogenesis of neurobrucellosis where its activation is a hallmark in this disease. In this study, we present in vitro evidence that type I interferons (IFN) are involved in the activation of microglia during Brucella abortus infection and are necessary to induce neuronal death. Neutralization of type I IFN receptor (IFNAR) on microglia cells completely abrogates neuronal loss in primary co-cultures of neurons/microglia infected with B. abortus or treated with culture supernatants from B. abortus-infected astrocytes. Type I IFN regulate inducible nitric oxide synthase (iNOS) expression, and subsequently nitric oxide (NO) production in microglia by increasing STAT1 expression and phosphorylation. Our results also show that NF-κB and the MAPK signaling pathways, ERK1/2 and p38, are implicated in the secretion of type I IFN induced by the bacterium. Finally, our results indicate that iNOS induction and NO production require activation of both NF-κB and STAT1 transcription factors. This observed molecular mechanism contributes to neuronal death induced by B. abortus-activated microglia and may help explain the neurological signs observed in patients with neurobrucellosis.

Keywords:  Brucella abortus; microglia; neurobrucellosis; neuronal death; nitric oxide; type I interferons

DOI:  https://doi.org/10.3389/fimmu.2025.1661395
Int J Mol Sci. 2025 Aug 22. pii: 8149. [Epub ahead of print]26(17):

A Semi-Automated and Unbiased Microglia Morphology Analysis Following Mild Traumatic Brain Injury in Rats.

Luke Sumberg, Rina Berman, Antoni Pazgier, Joaquin Torres, Jennifer Qiu, Bodhi Tran, Shannen Greene, Rose Atwood, Martin Boese, Kwang Choi.

  Mild traumatic brain injury (mTBI) affects over 40 million people every year. One of its features includes the activation of microglia, the resident immune cells of the brain. Microglia assume different morphological states depending on their level of activation, such as surveilling ramified and activated hypertrophic, ameboid, and rod-like microglia. These states can be distinguished by multiple features, including the shape, span, and branching of microglia. Male Sprague-Dawley rats sustained mTBI using the Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA) (3 times, 1.5 J per impact) or sham treatment. Four days after the injury, brains were collected and stained for microglia using the ionized calcium-binding adapter molecule-1 (Iba-1) antibody. Cortical injury sites were identified in a subset of CHIMERA animals. Using the MicrogliaMorphology ImageJ plugin and the MicrogliaMorphologyR package, 27 morphological features were quantified from individual microglia, and k-means clustering was used to classify microglia as ramified, rod-like, ameboid, and hypertrophic states. The CHIMERA injury altered microglia morphology features, which contributed to increased hypertrophic (activated) and decreased ramified (inactive) microglia compared to the sham controls. Combined with the clinically relevant mTBI paradigm and semi-automated/unbiased approach, the current findings may contribute to microglia morphology classification.

Keywords:  cortical injury; microglia morphology; mild traumatic brain injury; neuroinflammation; sprague-dawley rats

DOI:  https://doi.org/10.3390/ijms26178149
Int Immunopharmacol. 2025 Sep 06. pii: S1567-5769(25)01485-7. [Epub ahead of print]165 115494

The immunoregulator β-glucan produces antidepressant effects through microglia-mobilized astrocytic P2Y1R-BDNF signaling in the dentate gyrus.

Rongrong Song, Rongrong Yang, Xu Lu, Yiming Gu, Fu Li, Wenfeng Hu, Zhuo Chen, Lin Zhang, Chao Huang, Lijun Liu.

  β-Glucan, a polysaccharide from Saccharomyces cerevisiae with immunomodulatory activities that may not trigger pro-inflammatory responses in microglia, has been reported to show rapid antidepressant effects in chronically stressed animals by restoring microglial function in the dentate gyrus. However, the mechanisms underlying this effect of β-glucan are still largely unclear. Considering the importance of astrocytic purinergic 2Y1 receptors (P2Y1Rs) and brain-derived neurotrophic factor (BDNF) in the antidepressant effects of microglial stimulation, we hypothesize that β-glucan produces antidepressant effects by mobilizing astrocytic P2Y1R-triggered BDNF signaling in the hippocampus. Our results showed that a single injection of β-glucan (20 mg/kg) reversed chronic unpredictable stress (CUS)-induced depression-like behavior and decreased adenosine triphosphate (ATP) levels in the dentate gyrus of mice, which was abolished by chemogenetic inhibition of microglia. Degradation of endogenous ATP by apyrase, non-specific antagonism of purinergic receptors by suramin, specific antagonism of P2Y1Rs in the hippocampus or selective deletion of P2Y1R in astrocytes was able to abolish the antidepressant effect of β-glucan. In addition, the β-glucan-induced increase of BDNF in the dentate gyrus of CUS mice was abolished by chemogenetic inhibition of microglia, selective deletion of P2Y1Rs in astrocytes or depletion of endogenous ATP in the hippocampus. Further analysis showed that antagonism of BDNF signaling in the hippocampus abolished the antidepressant effect of β-glucan. These results suggest that ATP-triggered astrocytic P2Y1R signaling may mediate the antidepressant effect of β-glucan by promoting BDNF production in the hippocampus.

Keywords:  Astrocytic P2Y1R; BDNF; Dentate gyrus; Microglia; β-Glucan

DOI:  https://doi.org/10.1016/j.intimp.2025.115494
CNS Neurosci Ther. 2025 Sep;31(9): e70565

Repopulating Microglia Suppress Peripheral Immune Cell Infiltration to Promote Poststroke Recovery.

Ligen Shi, Lingxiao Lu, Jun Hu, Jiarui Chen, Qia Zhang, Ziyang Jin, Zhen Wang, Zhe Zheng, Jianmin Zhang.

   AIMS: Sustained neuroinflammation following ischemic stroke impedes post-injury tissue repairment and neurological functional recovery. Developing innovative therapeutic strategies that simultaneously suppress detrimental inflammatory cascades and facilitate neurorestorative processes is critical for improving long-term rehabilitation outcomes.
METHODS: We employed a microglia depletion-repopulation paradigm by administering PLX5622 for 7 days post-ischemia; followed by a 7-day withdrawal period to allow microglia repopulation. Single-cell transcriptomics, behavioral testing, cytokine arrays, flow cytometry, and immunofluorescence were used to assess the effects of microglia repopulation and delineate the transition of reshaped immune microenvironment.
RESULTS: PLX5622 administration reshaped the poststroke immune microenvironment, promoting neurofunctional recovery. Repopulated microglia adopted a homeostatic phenotype, increasing homeostatic states by ~14.36% and reducing pro-inflammatory states by ~20.17%. This reshaped environment suppressed T cell exhaustion, limited neutrophil terminal differentiation, and promoted a phagocytic macrophage phenotype. Furthermore, we identified that these transitions in infiltrating immune cells may be driven by reduced chemokine production, enhanced blood-brain barrier (BBB) integrity, and transcriptional reprogramming.
CONCLUSION: Transient microglial depletion and repopulation via PLX5622 during the acute phase post stroke facilitate the recovery of neurological function. This immunomodulatory strategy offers a promising and clinically translationally relevant approach to enhance functional recovery following ischemic brain injury.

Keywords:  PLX5622; immunomodulation; neuroinflammation; replenished microglia

DOI:  https://doi.org/10.1111/cns.70565
CNS Neurosci Ther. 2025 Sep;31(9): e70606

Neuroprotective Effects of Transcranial Pulsed Current Stimulation: Modulation of Microglial Polarization in Traumatic Brain Injury.

Peng Yao, Bingkai Ren, Qianhui Zhou, Yang Bai, Zhen Feng.

   OBJECTIVE: Traumatic brain injury (TBI), a prevalent neurological disorder worldwide, is marked by varying degrees of neurological dysfunction. A key contributor to secondary damage and impediments in the repair process is the unregulated activation of microglia, which triggers neuroinflammation. Emerging evidence highlights the therapeutic potential of transcranial pulsed current stimulation (tPCS) in mitigating neurological deficits. However, despite these promising neuroprotective effects, its role and exact mechanisms in TBI remain unclear.
METHODS: Herein, a mouse model of TBI was established, and daily 30-min tPCS treatments were administered for five consecutive days. Subsequently, we conducted comprehensive assessments of neurological function, microglial activation status, and neuroplasticity in the treated subjects. Additionally, a co-culture system of BV2 and HT22 cells was developed, using LPS to activate microglia, to explore potential neuroprotective mechanisms.
RESULTS: Our findings revealed that tPCS plays a crucial role in mitigating neuroinflammation and promoting neurological recovery following TBI. The underlying mechanism likely involves tPCS enhancing orexin-A (OX-A) expression, which subsequently suppresses the NF-κB pathway and promotes the expression of neurorepair-related markers. In vitro experiments further clarified these findings, demonstrating that OX-A effectively inhibited LPS-induced M1 microglial polarization and promoted a shift towards the M2 phenotype. Furthermore, OX-A significantly reduced intracellular ROS production and microglia-induced neuronal apoptosis.
CONCLUSION: These findings indicate that tPCS regulates microglial phenotype via the OX-A/NF-κB pathway, thereby suppressing neuroinflammation and enhancing neuroplasticity. These results provide a new perspective for the rehabilitation of individuals with TBI.

Keywords:  NF‐κB pathway; microglia; neuroplasticity; orexin‐A; transcranial pulsed current stimulation; traumatic brain injury

DOI:  https://doi.org/10.1111/cns.70606
Neurobiol Dis. 2025 Sep 09. pii: S0969-9961(25)00314-6. [Epub ahead of print] 107097

Sex differences of synaptic plasticity and microglial remodeling in the dorsal hippocampus following trigeminal nerve injury in mice.

Manindra Nath Tiwari, Lauren Paik, Fernando da Silva Fiorin, Man-Kyo Chung.

  Peripheral nerve injury patients have chronic pain as well as poor memory and cognitive functioning that is associated with hippocampal abnormalities. Despite sex-dependent changes in the hippocampus of patients with chronic pain, detailed sex differences in hippocampal plasticity after peripheral nerve injury are not well known. In mice with infraorbital nerve chronic constriction injury (ION-CCI), we found complex sex differences in the dorsal hippocampus (dHC). ION-CCI suppressed population spikes amplitude and long-term potentiation (LTP) in the dHC compared to sham group, which was consistent in females but not males. The field excitatory postsynaptic potential was comparable between sexes in the sham group, and ION-CCI suppressed it in both sexes. Short-term facilitation after paired-pulse protocol was also comparable between the sexes in the sham group but was only suppressed in males with ION-CCI. While microglial numbers in the dHC were comparable between the sexes, the proportion of hyper-ramified microglia was higher in males in the sham group. ION-CCI increased the total number of microglia in both sexes; however, the proportion of hyper-ramified microglia was increased by ION-CCI in females only. In novel object recognition tests, female mice exhibited better object recognition memory than males in the sham group, which was impaired by ION-CCI. Taken together, these results suggest that female mice exhibit stronger object recognition in the uninjured condition, which may be related to stronger hippocampal synaptic functions and potentiation. Furthermore, trigeminal nerve injury may produce a greater effect on synaptic functions and plasticity, along with cognitive deficits, in females.

Keywords:  Excitatory post-synaptic potential; Field potential, long-term potentiation; Memory; Microglia; Nerve injury, hippocampus

DOI:  https://doi.org/10.1016/j.nbd.2025.107097
Brain Behav. 2025 Sep;15(9): e70850

KLF7 Blocks MKNK2/HIF-1 Pathway-Mediated M1 Microglia Polarization to Ameliorate Ischemic Stroke-Induced Neurological Injury.

Ran Wei, Shuang Li, Lei Tang.

   BACKGROUND: Ischemic stroke (IS) is a common neurological disease with a significant financial burden but lacks effective drugs. This study sought to explore the mechanisms underlying MAP kinase-interacting serine/threonine-protein kinase 2 (MKNK2), a gene enriched in the hypoxia-inducible factor-1 (HIF-1) signaling, in IS-related neurological injury.
METHODS: Middle cerebral artery occlusion/reperfusion (MCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R) models were used in vivo and in vitro. Rats were infected with lentiviral vectors harboring knockdown or overexpression of the target genes, followed by MCAO/R to conduct 2,3,5-triphenyltetrazolium chloride, HE, Fluoro-Jade C, and TUNEL, enzyme-linked immunosorbent assay, immunohistochemistry, and neurological deficits assessment. The regulation of Krueppel-like factor 7 (KLF7) on MKNK2 was analyzed by ChIP and dual-luciferase assays. The effects of the KLF7/MKNK2/HIF-1 axis on the M1 or M2 polarization of rat microglia were demonstrated by the transfection of knockdown or overexpression plasmids into the cells.
RESULTS: MCAO/R-treated rat brain tissues and OGD/R-treated rat microglia showed MKNK2 upregulation along with activation of the HIF-1 signaling, whereas KLF7 expression was downregulated. Knockdown of MKNK2 inhibited the HIF-1 signaling and M1 microglia polarization, whereas it promoted M2 polarization. KLF7 repressed the MKNK2 transcription, thereby achieving the same effect as the knockdown of MKNK2 in vitro, which was reversed by combined overexpression of MKNK2. Knockdown of MKNK2 or overexpression of KLF7 ameliorated MCAO/R-induced brain damage and neurological injury in rats. MKNK2 overexpression reversed the alleviating effect of KLF7 overexpression on pathological brain injury in rats.
CONCLUSION: Significant downregulation of KLF7 expression after IS exacerbated pathological brain damage through the MKNK2-mediated HIF-1 pathway.

Keywords:  HIF‐1 pathway; Ischemic stroke; KLF7; MKNK2; microglia

DOI:  https://doi.org/10.1002/brb3.70850
SLAS Technol. 2025 Sep 10. pii: S2472-6303(25)00105-0. [Epub ahead of print] 100347

High-Throughput Cytokine Detection Platform for Evaluation of Chemical Induced Microglial Activation.

Shu Yang, Kelly E Carstens, Ibukunoluwa Ipaye, Xing Chen, Helena T Hogberg, Nicole Kleinstreuer, Thomas B Knudsen, Menghang Xia.

  Environmental chemical exposure, such as pesticides and heavy metals, may contribute to neurodegenerative disorders through neuroinflammation. This study aims to identify suitable in vitro microglial models for assessing cytokine responses to potential neurotoxicants, particularly focusing on human induced pluripotent stem cell-derived microglia (hiMG). In this study, we evaluated the cytokine secretion profiles of four microglial cell types-hiMG, HMC3, IM-HM, and BV2-upon stimulation with lipopolysaccharides (LPS) using cytokine arrays. Our findings showed cytokine response patterns in hiMG cells that most closely resemble in vivo conditions, with significant increases in interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α) levels, the latter being uniquely expressed after LPS treatment. Consequently, we developed a homogeneous time-resolved fluorescence (HTRF) assay platform in a 1536-well plate format for high-throughput screening of environmental chemicals using hiMG cells. After LPS treatment, the assay window for secretion of IL-6 and TNF-α increased 3.71-fold and 2.62-fold over the vehicle control group, respectively, with respective EC50 values of approximately 50 ng/mL and 90 ng/mL for IL-6 and TNF-α. We also assessed the response activity of hiMG to other stimuli, including interferon gamma and various catecholamine compounds, and nine environmental chemicals with evidence of cytokine-inducing potential in other in vitro assays. While all nine tested agents stimulated IL-6 and TNF-α production, three compounds (e.g., picoxystrobin) showed significant stimulation of both cytokines. This study establishes a reliable high-throughput platform for detecting inflammatory effects of environmental toxicants in a microglial cell assay, contributing valuable insights into their neuroinflammatory potential and possible implications for neurodegenerative disorders.

Keywords:  Cytokine; High-throughput screening; IL-6; Microglia; Neuroinflammation; TNF-α

DOI:  https://doi.org/10.1016/j.slast.2025.100347
J Stroke Cerebrovasc Dis. 2025 Sep 05. pii: S1052-3057(25)00224-1. [Epub ahead of print]34(11): 108447

Miltirone attenuates post-ischemic stroke neuroinflammation and microglial lipid metabolism via regulating LBP and TLR4/NF-κB Axis.

Gui-Xian Cai, Kai-Kai Guo.

   BACKGROUND: Ischemic stroke is a leading cause of neurological disability. Current therapies fail to address its multifactorial pathologies. Miltirone, a bioactive compound from Salvia miltiorrhiza, has shown antioxidative and anti-inflammatory potential. However, its neuroprotective mechanisms in stroke remain unexplored.
METHODS: Using young/aged dMCAO models and OGD/R-treated BV2 microglia, we evaluated Miltirone's effects on infarct volume, neurological function, microglial polarization, lipid metabolism. Cerebral infarct volume was quantified by TTC staining. Neurological deficits were assessed via mNSS, rotarod, and adhesive removal tests. Cell viability was determined by CCK-8 assay. Pro-/anti-inflammatory cytokines, SOD activity and MDA content were measured by ELISA. Microglial polarization was analyzed via immunofluorescence and RT-qPCR. TLR4/MyD88/NF-κB pathway proteins and PLN2 were analyzed by Western blot. Lipid metabolism was evaluated by BODIPY staining. ROS was measured by flow cytometry RESULTS: Miltirone reduced cerebral infarct volume, attenuated brain edema, and improved neurological/motor recovery in dMCAO mice. It shifted microglial polarization toward the anti-inflammatory M2 phenotype by suppressing M1 markers and enhancing M2 markers. Miltirone downregulated pro-inflammatory cytokines while elevating anti-inflammatory cytokines. Miltirone restored lipid homeostasis by inhibiting lipid synthesis genes and activating lipolysis genes. This reduced lipid accumulation. Mechanistically, Miltirone suppressed LBP expression and TLR4/MyD88/NF-κB pathway. Moreover, Miltirone mitigated oxidative stress by lowering ROS, restoring SOD activity, and reducing lipid peroxidation.
CONCLUSION: Miltirone confers neuroprotection through multi-target actions. It simultaneously provides neuroinflammation, regulates lipid metabolism, and counters oxidative stress. This occurs via LBP/TLR4/NF-κB axis modulation. Its multitarget action addresses the complexity of ischemic stroke pathophysiology, positioning it as a promising therapeutic candidate for clinical translation.

Keywords:  Ischemic stroke; LBP; Miltirone; TLR4/NF-κB

DOI:  https://doi.org/10.1016/j.jstrokecerebrovasdis.2025.108447