bims-microg 2025-07-06 papers

bims-microg

Biomed News

on Microglia in health and disease

Issue of 2025–07–06
27 papers selected by
Marcus Karlstetter, Universität zu Köln

Excitatory-neuron-derived interleukin-34 supports cortical developmental microglia function.
TET2-mutant myeloid cells mitigate Alzheimer's disease progression via CNS infiltration and enhanced phagocytosis in mice.
Microglial cyclooxygenase-1 modulates cerebral capillary basal tone in vivo in mice.
Connexin43 hemichannel blockade turns microglia neuroprotective and mitigates cognitive deficits in a mouse model of amyloidosis.
Glial reactivity correlates with synaptic dysfunction across aging and Alzheimer's disease.
Variable and interactive effects of Sex, APOE ε4 and TREM2 on the deposition of tau in entorhinal and neocortical regions.
Decoding DNA sequence-driven evolution of the human brain epigenome at cellular resolution.
Dependence of fasting-induced hypothalamic anti-inflammatory microglia mechanisms on adrenal glucocorticoid secretion.
Microglial cGAS-STING-TBK1 activation in paraventricular thalamus mediates sleep and emotional disturbances in lupus mice.
Locus coeruleus integrity correlates with plasma soluble Axl levels in Alzheimer's disease patients.
Small-diffusible aggregates, plaques, tangles, and dynamic equilibria: Untangling Alzheimer's disease.
MiR-125a-5p in extracellular vesicles of neural stem cells acts as a crosstalk signal modulating neuroinflammatory microenvironment to alleviate cerebral ischemia-reperfusion injury.
Single-cell transcriptomics of vascularized human brain organoids decipher lineage-specific stress adaptation in fetal hypoxia-reoxygenation injury.
Brain targeted lipid nanoparticles with Hv1 inhibitors alleviate neuroinflammation post-ischemic stroke.
EphB2-mediated ephrin-B reverse signaling on microglia drives an anti-viral, but inflammatory and neurotoxic response associated with HIV.
Immunomodulation of inflammatory responses preserves retinal integrity in murine models of pericyte-depletion retinopathy.
Melatonin Ameliorate neuroinflammation in activated microglia through the Aryl hydrocarbon-Nrf2 axis.
Behavioral assessment and gene expression changes in a mouse model with dysfunctional STAT1 signaling.
NR4A2 attenuates early brain injury after intracerebral hemorrhage by promoting M2 microglial polarization via TLR4/TRAF6/NF-κB pathway inhibition.
Interferons and Toxoplasma gondii shape PD-L1 regulation in retinal barrier cells: the critical role of proteases.
Automated image analysis software for the study and quantification of retinal glial cells.
Glial and immune dysregulation in glaucoma independent of retinal ganglion cell loss: a human post-mortem histopathology study.
Opposing role of phagocytic receptors MERTK and AXL in Progranulin deficient FTD.
CCL2 activates NLRP3 inflammasomes to regulate microglial phenotype transformation to promote central sensitisation in chronic migraine.
Phosphodiesterase 2A as a Therapeutic Target for Relieving Mechanical Allodynia and Modulating Microglial Polarization in Neuropathic Pain Models Following Spinal Cord Injury.
Mbnl1 Protects Against Cerebral Ischemia-Reperfusion Injury by Modulating Microglia/Macrophage Polarization via NF-κB Pathway.
mRNA vaccination mitigates pathological retinochoroidal neovascularization in animal models.

Immunity. 2025 Jun 26. pii: S1074-7613(25)00249-3. [Epub ahead of print]

Excitatory-neuron-derived interleukin-34 supports cortical developmental microglia function.

Benjamin A Devlin, Dang M Nguyen, Diogo Ribeiro, Gabriel Grullon, Madeline J Clark, Amelie Finn, Alexis M Ceasrine, Seneca Oxendine, Martha Deja, Ashka Shah, Shomik Ati, Anne Schaefer, Staci D Bilbo.

  Neuron-microglia interactions dictate the development of neuronal circuits in the brain. However, the factors that regulate these processes across development are largely unknown. Here, we found that interleukin-34 (IL-34), a neuron-derived cytokine, was upregulated in early development and maintained neuroprotective, mature microglia in the anterior cingulate cortex (ACC) of mice. IL-34 expression increases in the second week of post-natal life and was primarily produced by excitatory neurons. Excitatory-neuron-specific deletion of IL-34 reduced microglia numbers and microglial TMEM119 expression and increased aberrant microglial phagocytosis of excitatory thalamocortical synapses in the ACC. Acute, low-dose blocking of IL-34 at post-natal day 15 similarly decreased microglial TMEM119 and aberrantly increased microglial phagocytosis of synapses. Viral overexpression of IL-34 induced TMEM119 expression and prevented appropriate microglial phagocytosis of synapses. These findings establish IL-34 as a key regulator of neuron-microglia crosstalk in post-natal brain development, controlling both microglial maturation and synapse engulfment.

Keywords:  CSF-1R; Il-34; TMEM119; behavior; development; microglia; neuroimmune; phagocytosis; synapse

DOI:  https://doi.org/10.1016/j.immuni.2025.06.002
Cell Stem Cell. 2025 Jun 24. pii: S1934-5909(25)00228-0. [Epub ahead of print]

TET2-mutant myeloid cells mitigate Alzheimer's disease progression via CNS infiltration and enhanced phagocytosis in mice.

Katie A Matatall, Trisha K Wathan, Minh Nguyen, Hu Chen, Alexandra McDonald, Guantong Qi, Julia A Belk, Marcus A Florez, Duy T Le, Temitope Olarinde, Caitlyn Vlasschaert, Marco M Buttigieg, Chih-Wei Fan, Saul Carcamo, Ruoqiong Cao, Daniel E Kennedy, Arushana A Maknojia, Apoorva Thatavarty, Josaura V Fernandez Sanchez, Hind Bouzid, Surabi Veeraragavan, Susan Crocker, Margaret A Goodell, Antony Rodriguez, Siddhartha Jaiswal, Michael J Rauh, Eirini P Papapetrou, Samuele G Marro, Katherine Y King.

  Clonal hematopoiesis (CH) is associated with many age-related diseases, but its interaction with Alzheimer's disease (AD) remains unclear. Here, we show that TET2-mutant CH is associated with a 47% reduced risk of late-onset AD (LOAD) in the UK Biobank, whereas other drivers of CH do not confer protection. In a mouse model of AD, transplantation of Tet2-mutant bone marrow reduced cognitive decline and β-amyloid plaque formation, effects not observed with Dnmt3a-mutant marrow. Bone-marrow-derived microglia-like cells were detected at an increased rate in Tet2-mutant marrow recipients, and TET2-mutant human induced pluripotent stem cell (iPSC)-derived microglia were more phagocytic and hyperinflammatory than DNMT3A-mutant or wild-type microglia. Strikingly, single-cell RNA sequencing (scRNA-seq) revealed that macrophages and patrolling monocytes were increased in brains of mice transplanted with Tet2-mutant marrow in response to chemokine signaling. These studies reveal a TET2-specific protective effect of CH on AD pathogenesis mediated by peripheral myeloid cell infiltration.

Keywords:  Alzheimer’s disease; DNMT3A; TET2; clonal hematopoiesis; inflammation; microglia, peripheral immune cells; myeloid cell activation; phagocytosis

DOI:  https://doi.org/10.1016/j.stem.2025.06.006
Nat Commun. 2025 Jul 01. 16(1): 5704

Microglial cyclooxygenase-1 modulates cerebral capillary basal tone in vivo in mice.

William A Mills, Niesha A Savory, Aida Oryza Lopez-Ortiz, Dennis H Lentferink, Fernando González Ibáñez, Praise Agochi, Elina Rastegar, Arnav Gupta, Deetya Gupta, Arya Suram, Brant E Isakson, Marie-Ève Tremblay, Ukpong B Eyo.

Microglia and border associated macrophages have been implicated in hypercapnia, but it is unknown which myeloid cell modulates which vessel type. Previously, we documented in mice myeloid cell association with the brain vasculature but did not distinguish their localization along the vascular tree. Using molecular approaches to distinguish microglia and perivascular macrophages, we show that microglia are the only myeloid cells associating with capillaries. To determine if loss of microglia is sufficient to reduce capillary tone, we employ global and focal ablations and find significant reductions in capillary diameter and red blood cell flux, suggesting vasodilatory regulation by microglia. Cyclooxygenase-1 (COX1), an enzyme with known vasodilatory action, is predominantly expressed by microglia. To determine the necessity of microglial COX1 in regulating cerebral basal capillary tone in vivo, we perform genetic ablation and find a significant reduction in capillary flux and diameter. Together, this study using male mouse models reveals a role for microglial COX1 in maintaining basal capillary tone in vivo.

DOI: https://doi.org/10.1038/s41467-025-60753-x
Nat Commun. 2025 Jul 01. 16(1): 5621

Connexin43 hemichannel blockade turns microglia neuroprotective and mitigates cognitive deficits in a mouse model of amyloidosis.

Yixun Su, Hui Li, Wenjie Zhang, Shi Tao, Qi Wang, Xuan Zhang, Mi Zhou, Xiaomin Huang, Chenmeng Wang, Yong Tang, Hui Chen, Alexei Verkhratsky, Zhengbao Zha, Jianqin Niu, Chenju Yi.

Alzheimer's disease (AD), the leading cause of senile dementia, lacks effective therapies. While microglia are central to AD pathology, key therapeutic targets remain unclear. Here we identify microglial connexin43 (Cx43) hemichannels as a regulator of microglial reactivity in AD, positioning them as a promising therapeutic target. Post-mortem AD patient tissue showed elevated Cx43 levels in periplaque microglia. In the APPswe/PS1dE9 (APP/PS1) mouse model of amyloidosis, we demonstrated that microglial Cx43 hemichannels correlated with microglial malfunction, which in turn exacerbated β-amyloid pathology. Ablation of microglial Cx43 hemichannels by genetic knockout shifts microglia to a neuroprotective phenotype, enhancing the microglia-plaque interaction while suppressing neurotoxicity, thereby mitigating the progression of AD-like pathology. We developed TAT-Cx43@LNPs, a Cx43 hemichannel-targeting peptide delivered by a lipid nanoparticle system, which effectively delayed and rescued β-amyloid-related neuropathology and cognitive impairment in APP/PS1 mice. This study provides evidence for advancing Cx43 hemichannel targeting therapy into clinical trials.

DOI: https://doi.org/10.1038/s41467-025-60746-w
Nat Commun. 2025 Jul 01. 16(1): 5653

Glial reactivity correlates with synaptic dysfunction across aging and Alzheimer's disease.

Francieli Rohden, Pamela C L Ferreira, Bruna Bellaver, João Pedro Ferrari-Souza, Cristiano S Aguzzoli, Carolina Soares, Sarah Abbas, Hussein Zalzale, Guilherme Povala, Firoza Z Lussier, Douglas T Leffa, Guilherme Bauer-Negrini, Nesrine Rahmouni, Cécile Tissot, Joseph Therriault, Stijn Servaes, Jenna Stevenson, Andrea L Benedet, Nicholas J Ashton, Thomas K Karikari, Dana L Tudorascu, Henrik Zetterberg, Kaj Blennow, Eduardo R Zimmer, Diogo Souza, Pedro Rosa-Neto, Tharick A Pascoal.

Previous studies suggest glial and neuronal changes may trigger synaptic dysfunction in Alzheimer's disease (AD), but the link between their markers and synaptic abnormalities in the living brain remains unclear. We investigated the association between glial reactivity and synaptic dysfunction biomarkers in cerebrospinal fluid (CSF) from 478 individuals in cognitively unimpaired (CU) and cognitively impaired (CI) individuals. We measured amyloid-β (Aβ), phosphorylated tau (pTau181), astrocyte reactivity (GFAP), microglial activation (sTREM2), and synaptic markers (GAP43, neurogranin). CSF GFAP levels were associated with presynaptic and postsynaptic dysfunction, independent of cognitive status or Aβ presence. CSF sTREM2 levels were related to presynaptic markers in cognitively unimpaired and impaired Aβ+ individuals, and to postsynaptic markers in cognitively impaired Aβ+ individuals. Notably, CSF pTau mediated the relationships between GFAP or sTREM2 and synaptic dysfunction. Our findings, validated in two independent cohorts (TRIAD and ADNI), reveal a distinct pattern of glial contribution to synaptic degeneration.

DOI: https://doi.org/10.1038/s41467-025-60806-1
Nat Commun. 2025 Jul 01. 16(1): 5812

Variable and interactive effects of Sex, APOE ε4 and TREM2 on the deposition of tau in entorhinal and neocortical regions.

Alzheimer’s Disease Neuroimaging Initiative

The canonical Alzheimer's Disease (AD) pathological cascade posits that the accumulation of amyloid beta (Aβ) is the initiating event, accelerating the accumulation of tau in the entorhinal cortex (EC), which subsequently spreads into the neocortex. Here in a multi-cohort study (ADNI, A4, HABS-HD) of 1354 participants with multimodal imaging and genetic information we queried how genetic variation affects these stages of the AD cascade. We observed that females and APOE-ε4 homozygotes are more susceptible to the effects of Aβ on the primary accumulation of tau, with greater EC tau for a given level of Aβ. Furthermore, we observed for individuals who have rare risk variants in TREM2 and/or APOE-ε4 homozygotes there was a greater spread of primary tau from the EC into the neocortex. These findings offer insights into the function of sex, APOE and microglia in AD progression and have implications for determining personalised treatment with drugs targeting Aβ and tau.

DOI: https://doi.org/10.1038/s41467-025-60370-8
Nat Commun. 2025 Jul 01. 16(1): 5625

Decoding DNA sequence-driven evolution of the human brain epigenome at cellular resolution.

Emre Caglayan, Genevieve Konopka.

DNA-based evolutionary comparisons of regulatory genomic elements enable insight into functional changes driven in cis, partially overcoming tissue inaccessibility. Here, we harnessed adult and fetal cortex single-cell ATAC-seq datasets to uncover DNA substitutions specific to the human and human-ancestral lineages within apes. We found that fetal microglia identity is evolutionarily divergent in all lineages, whereas other cell types are conserved. Using multiomic datasets, we further identified genes linked to multiple lineage-divergent gene regulatory elements and implicated biological pathways associated with these divergent features. We also uncovered patterns of transcription factor binding site evolution across lineages and identified expansion of bHLH-PAS transcription factor targets in human-hominin lineages, and MEF2 transcription factor targets in the ape lineage. Finally, conserved features were more enriched in brain disease variants, whereas there was no distinct enrichment of brain disease variants on the human lineage compared to its ancestral lineages. Our study identifies ancestral evolutionary patterns of the human brain epigenome at cellular resolution.

DOI: https://doi.org/10.1038/s41467-025-60665-w
Brain Behav Immun. 2025 Jun 30. pii: S0889-1591(25)00255-7. [Epub ahead of print]

Dependence of fasting-induced hypothalamic anti-inflammatory microglia mechanisms on adrenal glucocorticoid secretion.

Balázs Juhász, Krisztina Horváth, Dániel Kuti, Szilamér Ferenczi, Zsuzsanna Winkler, Krisztina J Kovács.

   INTRODUCTION: Fasting triggers complex physiological and neuroimmune adaptations, yet its impact on hypothalamic microglia and the underlying regulatory role of glucocorticoids remains incompletely understood. The present study focused on fasting-induced systemic changes and cellular adaptations seen in the hypothalamus where components of metabolic- hormonal- and immune regulations are integrated.
METHODS: Adult male microglia reporter (CX3CR1+/Gfp) mice were subjected short term (18 h) overnight fasting. Metabolic changes were followed using indirect calorimetry. Hypothalamic expression of pro-and anti-inflammatory markers, hypothalamic neuropeptides and select genes involved in metabolic regulation was measured by qPCR. Number of microglia and their morphological characteristics was analysed by Sholl analysis. The dependence of these markers on fasting-induced corticosterone was studied in adrenalectomized (ADX) or metyrapone-treated mice. Plasma levels of corticosterone and ketone body, β-hydroxybutyrate was assayed by radioimmunassay and a colorimetric kit respectively.
RESULTS: Overnight fasting resulted in a decrease in energy expenditure and respiratory exchange ratio (RER) indicating conservation of energy and a metabolic shift towards utilization of fatty acids as alternative energy source. Fasting increased hypothalamic expression of orexigenic neuropeptides and mRNA levels of Pdk4, Glut1, and Mct2 genes, in line with metabolic compensation. Upregulation of hypothalamic Crh and increased plasma concentration of corticosterone indicated sustained activation of the HPA axis. Importantly, fasting promoted an anti-inflammatory milieu in the hypothalamus characterized by elevated Il-4, Il-10 and IkBα genes without significant activation of pro-inflammatory cytokines (e.g., Il-1β, Il-6, Tnfα). Morphological analysis revealed region-specific changes in microglia number and branching complexity, particularly in hypothalamic regions directly exposed to blood-borne signals. Functional profiling showed increased microglial expression of IkBα and decreased pIkBα, indicating suppressed NFkB signaling. Adrenalectomy (1 week) and acute pharmacological inhibition of corticosterone synthesis (methyrapone) revealed that fasting-induced anti-inflammatory and metabolic gene expression, as well as microglial plasticity were largely glucocorticoid dependent. Hypothalamic expression of fasting-related neuropeptides (Npy, Agrp) and genes, related to the metabolic shift (Pdk4, Glut-1, Mct2, Angptl4) as well as some immune-related genes (Il10, Iba1) was dependent on presence of the adrenal gland or fasting-induced elevation of corticosterone.
CONCLUSION: These findings highlight short term fasting as a potent modulator of hypothalamic immune-metabolic crosstalk and reveal critical role of adrenal glucocorticoids in orchestrating microglial responses to energetic challenges. The results have potential implications for therapeutic interventions targeting metabolic and inflammatory disorders.

Keywords:  Adrenalectomy; Cytokine; Hypothalamus; Metyrapone; Mice; Microglia; NFkB; Neuropeptide; Overnight fasting; Ramification index; Sholl-analysis

DOI:  https://doi.org/10.1016/j.bbi.2025.06.038
Brain Behav Immun. 2025 Jul 01. pii: S0889-1591(25)00259-4. [Epub ahead of print]

Microglial cGAS-STING-TBK1 activation in paraventricular thalamus mediates sleep and emotional disturbances in lupus mice.

Hui Yuan, Zijie Li, Xueru Wang, Siyuan Zeng, Chenye Jin, Jingyu Chen, Xuejiao Wang, Pingting Yang, Ling Qin.

  Sleep and emotional disturbances are prevalent in systemic lupus erythematosus (SLE) patients, yet the neuroinflammatory mechanisms remain unclear. Here, we investigated this issue using pristane-induced lupus (PIL) mice. We firstly confirmed that PIL mice exhibited progressive fragmentation of NREM sleep and decreased cumulative sleep time, correlating with blood-brain barrier (BBB) leakage and IgG deposition in the paraventricular thalamus (PVT). Concurrently, PVT neurons showed aberrant excitatory activity, including a high level of cFos expression, decreased amplitude and increased rate of Ca2+ transients during wakefulness. Bulk RNA sequencing and protein analyses demonstrated upregulation of the cyclic GMP-AMP synthase (cGAS) -stimulator of interferon genes (STING) -TANK-binding kinase 1 (TBK1) activation pathway in PVT microglia, with elevated phosphorylation of STING (pSTING) and TBK1 (pTBK1), promoting synthesis of pro-inflammatory cytokines. Selectively knockdown STING in microglia effectively normalized PVT neuronal excitability, restored sleep homeostasis, and ameliorated anxiety/depression-like behaviors. Notably, we identified selective expression of cannabinoid receptor type 2 (CB2R) in PVT microglia. Pharmacological CB2R activation could inhibit TBK1 phosphorylation, attenuate microglial inflammatory responses, and improve sleep and emotional disturbances. Our findings elucidate a novel neuroimmune axis in SLE-related neuropsychiatric symptoms, offering potential therapeutic avenues for mitigating neuroinflammation and associated behavioral comorbidities in lupus.

Keywords:  CB2R; Microglia; Neuroinflammation; Sleep and emotional disturbances; Systemic lupus erythematosus; cGAS-STING-TBK1 pathway

DOI:  https://doi.org/10.1016/j.bbi.2025.06.042
Alzheimers Dement. 2025 Jul;21(7): e70434

Locus coeruleus integrity correlates with plasma soluble Axl levels in Alzheimer's disease patients.

Alessandro Galgani, Arnaud Mary, Francesco Lombardo, Nicola Martini, Marco Scotto, Gloria Tognoni, Gabriele Siciliano, Roberto Ceravolo, Filippo S Giorgi, Michael T Heneka.

   INTRODUCTION: Locus coeruleus (LC) is one of the earliest structures altered in Alzheimer's disease (AD). Inflammation is also now considered critical in AD pathology, early stage included. However, no association between LC degeneration and the peripheral inflammation has been reported yet.
METHODS: A cohort of 102 patients was studied for which both magnetic resonance imaging (MRI) scans and blood samples were available. LC integrity was assessed by MRI, and plasma soluble TAMs (Tyro3, Axl, and MerTK) receptor levels were measured by enzyme-linked immunosorbent assay (ELISA).
RESULTS: We found that plasma levels of the soluble TAMs receptor Axl were correlated with LC rostral degeneration in the whole cohort (p = 0.007), as well as in the AD+ group (p = 0.017), but not in the AD- group.
DISCUSSION: These results uncover a new relationship between peripheric markers of inflammation and central early AD neurodegeneration.
HIGHLIGHTS: In Alzheimer's disease, no link between locus coeruleus degeneration and microglial activation was reported. Plasma Axl, Tyro3, and MerTK levels and locus coeruleus integrity were assessed in Alzheimer's disease patients. Locus coeruleus integrity positively correlates with plasma AXL, linked to microglia activation. Axl-noradrenergic signaling interplay deserves further larger longitudinal studies.

Keywords:  Alzheimer's disease; blood‐based biomarkers; locus coeruleus; neuroinflammation; noradrenaline

DOI:  https://doi.org/10.1002/alz.70434
Alzheimers Dement. 2025 Jul;21(7): e70462

Small-diffusible aggregates, plaques, tangles, and dynamic equilibria: Untangling Alzheimer's disease.

Emre Fertan, Georg Meisl, David Klenerman.

   INTRODUCTION: Beta-amyloid plaques and hyperphosphorylated tau tangles are the neuropathological hallmarks of Alzheimer's disease; however, their relevance in the pathophysiology is not fully understood. It has been suggested that these larger and insoluble aggregates may not be the most toxic forms of beta-amyloid and tau in Alzheimer's disease, and the disease progression may actually be promoted by the small-diffusible aggregates.
METHODS AND RESULTS: We combine the recent findings from our group and other key research to put forward the hypotheses that the formation of the small-diffusible aggregates of beta-amyloid and tau and their larger insoluble counterparts is not a linear process.
DISCUSSION: While the small-diffusible aggregate formation of beta-amyloid and tau is a passive process, regulated by thermodynamic equilibria, the formation of large-insoluble aggregates is an active process, regulated by microglia and neurons, which to an extent is a protective mechanism against the toxicity of the smaller aggregates.
HIGHLIGHTS: Plaques and tangles may be made by active processes in Alzheimer's disease. The small-soluble aggregates may be the more toxic species in Alzheimer's disease. Pathology may be caused by the imbalance of production and clearance of aggregates. Plaques and tangle formation may be attempts to restore the homeostatic equilibrium.

Keywords:  Alzheimer's disease; beta‐amyloid; caspase; microglia; oligomer; plaque; post‐translational modification; small‐diffusible aggregate; tangle; tau; truncation

DOI:  https://doi.org/10.1002/alz.70462
Theranostics. 2025 ;15(14): 7064-7089

MiR-125a-5p in extracellular vesicles of neural stem cells acts as a crosstalk signal modulating neuroinflammatory microenvironment to alleviate cerebral ischemia-reperfusion injury.

Qingyue Liu, Heran Ma, Jing Liao, Zihan Zhu, Hongyuan Chen, Dong Sun, Longkun Wang, Lu Lu, Xiaowei Chen, Xinke Zhang, Fengshan Wang.

  Rationale: Ischemic stroke is the second leading cause of death worldwide. Ischemia-reperfusion injury plays a major role in brain function damage and leads to disability. Currently, there are no ideal therapeutic methods for preventing and treating ischemia-reperfusion injury. Extracellular vesicles (EVs) are a promising therapy for cerebral ischemia-reperfusion injury (CIRI). The main purpose of this study was to identify the pivotal miRNAs in EVs that affect functional recovery following CIRI, develop engineered EVs encapsulating key miRNAs, and identify the underlying mechanisms. Methods: Next-generation sequencing was used to identify the crucial differentiating ingredients between EVs from normoxia- and hypoxia-conditioned human neural stem cells (hNSCs). HNSC EVs were electroporated with miR-125a-5p mimics and characterized using nanoparticle tracking analysis and electron microscopy. The role and mechanism by which EV-packaged miR-125a-5p mediates CIRI were investigated in vitro and in vivo. Results: In the present study, miR-125a-5p derived from the EVs of hNSCs was found to signal the crosstalk between different cells, such as microglia and neurons, under ischemic conditions. Furthermore, hNSC-EVs loaded with miR-125a-5p (EVsmiR) promoted the polarization of anti-inflammatory M2 microglia, resulting in altered inflammatory responses and decreased inflammatory cytokine secretion. Additionally, EVs-miR-125a-5p exerts a significant impact on microglia, subsequently translocating to neurons and inhibiting neuronal death. Moreover, increased miR-125a-5p levels in hNSC-EVs effectively inhibited neuronal apoptosis and improved the axonal ultrastructure and neurological function in vivo. Mechanistically, EVsmiR regulate the TLR4/NF-κB signaling pathway by targeting IKBKG to alleviate neuroinflammation induced by CIRI. Conclusions: Our findings demonstrate that miR-125a-5p mechanisms contribute to modulating the neuroinflammatory microenvironment and miR-125a-5p-enriched EVs may be a promising therapeutic strategy for CIRI.

Keywords:  IKBKG; cerebral ischemia-reperfusion injury; extracellular vesicles; miR-125a-5p; neuroinflammation

DOI:  https://doi.org/10.7150/thno.115993
Theranostics. 2025 ;15(14): 7001-7024

Single-cell transcriptomics of vascularized human brain organoids decipher lineage-specific stress adaptation in fetal hypoxia-reoxygenation injury.

Simeng Yi, Min Huang, Chunmei Xian, Xi Kong, Shigang Yin, Jianhua Peng, Yong Zhang, Xiuju Du, Yong Jiang, Bingqing Xie, Huangfan Xie.

  Rationale: Fetal hypoxia, a major contributor to neonatal mortality, induces complex neurovascular disruptions in developing brains, yet human-specific cellular mechanisms remain poorly understood due to limitations in existing models. This study establishes an advanced vascularized human cortical organoid (vhCO) model to decode cell type-specific injury mechanisms and therapeutic targets during hypoxia-reoxygenation. Methods: We developed vhCOs by integrating cortical and vascular organoids, recapitulating mid-to-late gestational neurodevelopment with diverse lineages-neural progenitors, neurons, microglia, and functional vasculature with blood-brain barrier properties. Hypoxia-reoxygenation experiments were conducted on vhCOs, followed by single-cell transcriptomic profiling to dissect cellular responses. Results: Key findings include: (1) Lineage-specific vulnerabilities: astrocyte precursors exhibited developmental arrest, while immature GABAergic neurons (Subtype I) underwent neurogenic collapse. Microglia displayed a biphasic inflammatory response-initially suppressed, then hyperactivated post-reoxygenation, diverging from animal models; (2) Hypoxia memory persisted in non-neural cells (pericytes, fibroblasts), driving compartment-specific vascular remodeling via Notch signaling and collagen deposition; (3) Rewired neural-non-neural crosstalk networks (e.g., IGF2-IGF2R, LGALS3-MERTK, Wnts-SFRP2) revealed novel repair targets inaccessible to conventional models. Conclusions: By prioritizing single-cell resolution, this study delineates human-specific neurovascular pathophysiology and stress adaptation networks in hypoxic brain injury. The vhCO platform bridges translational gaps, offering a paradigm for precision therapeutics and advancing research on developmental brain disorders.

Keywords:  GABAergic neuron; blood-brain barrier; fetal hypoxia; single-cell RNA-sequencing; vascularized brain organoid

DOI:  https://doi.org/10.7150/thno.117001
J Nanobiotechnology. 2025 Jul 01. 23(1): 464

Brain targeted lipid nanoparticles with Hv1 inhibitors alleviate neuroinflammation post-ischemic stroke.

Zeyu Yang, Lei Jin, Longxiang Li, Yu Wu, Wenchao Liu, Xin Feng, Liyan Li, Fa Jin, Yiming Bi, Ran Li, Shenquan Guo, Yanan Wang, Boyang Wei, Yanchao Liu, Xifeng Li, Chuanzhi Duan.

   BACKGROUND: Ischemic stroke (IS) represents a significant global health burden. Current therapeutic options face problems such as window narrowing and reperfusion injury risk. Moreover, with increasing aging and risk factors, novel treatment strategies are urgently needed. NADPH oxidase (NOX)-mediated oxidative stress in microglia is a critical mechanism driving neuroinflammation and cell death. Hv1, a voltage-gated proton channel highly expressed in microglia, synergizes with NOX to generate reactive oxygen species (ROS), exacerbating brain damage. YHV984, a potent Hv1 inhibitor, alleviates post-IS neuroinflammation but faces clinical limitations due to potential toxic side effects and solubility issues. To improve the physicochemical and pharmacokinetic properties of YHV984 for specific Hv1 inhibition in the brain, the multifunctional nanoparticles consisting of a T7-targeting peptide and lipid nanoparticles (LNP) were developed to deliver YHV984 (T7-LNP@YHV984).
RESULTS: The results demonstrated that T7-LNP@YHV984 exhibited good stability and brain targeting capability, effectively crossing the blood-brain barrier (BBB) and accumulating within microglia. This targeted delivery significantly suppressed Hv1 expression and activation of the NLRP3 inflammasome pathway in the damaged brain. Furthermore, it promoted the polarization of microglia towards the M2 phenotype, enhancing the release of anti-inflammatory factors, alleviating neuroinflammation and improved neuronal survival. Additionally, T7-LNP@YHV984 improved survival and facilitated neurological recovery in post-IS mice.
CONCLUSIONS: T7-LNP@YHV984 multifunctional nanoparticles with long-term stability emerged as a potent strategy to alleviate reperfusion injury and inhibit neuroinflammation post-IS. By precisely targeting Hv1 in microglia, the nanoparticles effectively suppressed microglia-induced neuroinflammation, minimizing off-target effects. This innovation offers novel insights into stroke treatment and neuroprotective strategies.

Keywords:  Brain-targeted LNP; Ischemic stroke; Microglial; Neuroinflammation; Voltage-gated proton channel Hv1

DOI:  https://doi.org/10.1186/s12951-025-03540-6
J Neuroinflammation. 2025 Jun 30. 22(1): 171

EphB2-mediated ephrin-B reverse signaling on microglia drives an anti-viral, but inflammatory and neurotoxic response associated with HIV.

Jeffrey Koury, Hina Singh, Samantha N Sutley-Koury, Dominic Fok, Xinru Qiu, Ricky Maung, Benjamin B Gelman, Iryna M Ethell, Marcus Kaul.

   BACKGROUND: Pathological inflammation with a loss of synaptic integrity and function has been implicated in HIV Associated Neurocognitive Disorders (HAND). Although therapeutics exist to increase the lifespan of people living with HIV (PLWH), they are not effective at preventing neuroinflammation and HIV induced neuronal damage persists. In this study, we investigate the ephrin-B/EphB axis, which regulates inflammation, in post-mortem brain specimen of PLWH and experimental models in order to assess its potential role in HIV induced neuroinflammation.
METHODS: We analyze mRNA samples of post-mortem brain specimen of PLWH and uninfected controls obtained from the National NeuroAIDS Tissue Consortium (NNTC) and, for comparison, of a transgenic mouse model of neuroHIV using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Follow-up experiments employ mouse brain tissue and in vitro models, including immortalized human microglia, human induced pluripotent stem cell (iPSC)-derived mixed neuroglial cell cultures, cellular and molecular interference, functional and multiplex assays, immunofluorescence and mRNA sequencing to examine the role of the ephrin-B/EphB axis in neuroinflammation and the associated neurotoxicity.
RESULTS: Using qRT-PCR we find increased expression of EphB2 in post-mortem brain of PLWH, and detect a correlation with pro-viral DNA, viral RNA and an inverse correlation with abstract executive function and verbal fluency. Increased expression of ephrin-B/EphB at mRNA and protein level is also observed in brains of a transgenic mouse model of neuroHIV suggesting the upregulation can be driven, at least in part, by expression of viral gp120 envelope protein and a type I interferon, IFNβ. Additionally, we find induction of ephrin-B1 expression in microglia following activation by IFNβ. Given the previously reported impact of EphB2 on inflammation in the periphery, the functional role of EphB2-mediated ephrin-B reverse signaling on microglia is assessed for a pro-inflammatory and anti-viral signature. We find that EphB2 treated microglia secrete inflammatory and anti-viral factors but also exert contact-independent neurotoxicity. Finally, knockdown of microglial ephrin-B1, an EphB2 binding partner, shows a partial alleviation of the microglial pro-inflammatory signature and neurotoxicity.
CONCLUSION: Our study suggests that elevated EphB2, and its reverse signaling through ephrin-B1 in microglia contribute to neuroinflammation and neurotoxicity in neuroHIV.

Keywords:  EphB; Ephrin-B; HIV-1; Interferon-β; Microglia; Neuroinflammation; Neurotoxicity

DOI:  https://doi.org/10.1186/s12974-025-03481-9
JCI Insight. 2025 Jul 01. pii: e184465. [Epub ahead of print]

Immunomodulation of inflammatory responses preserves retinal integrity in murine models of pericyte-depletion retinopathy.

Urbanus Muthai Kinuthia, Christoph Möhle, Ralf H Adams, Thomas Langmann.

  The loss of integrity of the blood retina barrier (BRB) is a key pathological hallmark of vision-threatening complications in diabetic retinopathy (DR). Although DR is considered a microvascular disease, mounting evidence from mouse models and patients show that inflammation is closely connected with microvasculopathy. Inflammatory responses during retinal pathophysiology are often orchestrated by microglia, resident innate immune cells of the retina. However, the precise role of microglia activity during DR pathogenesis remains elusive. Here, we used an anti PDGFRβ antibody and inducible endothelial cell-specific PDGFB-KO during postnatal development of retinal vasculature to reproduce key features of DR pathology in mice. In addition, we applied a minocycline therapy to modulate retinal inflammation. Postnatal depletion of pericytes or loss of PDGFB in retinal vessels altered BRB integrity, triggered secretion of angiogenic and inflammatory factors with concomitant microglia reactivity, which was sustained in mature retinas. Microglia reactivity was accompanied by upregulation of disease-associated genes. Notably, minocycline attenuated the cycle of inflammatory responses in young and mature retinas, thereby preserving retinal vascular and structural integrity in mice. Together, our findings suggest that immunomodulation of microglia-driven inflammatory responses preserves retinal vasculature and maintains BRB integrity in two different mouse models of human DR.

Keywords:  Cellular immune response; Diabetes; Immunology; Ophthalmology; Retinopathy

DOI:  https://doi.org/10.1172/jci.insight.184465
Int J Biol Sci. 2025 ;21(9): 3917-3933

Melatonin Ameliorate neuroinflammation in activated microglia through the Aryl hydrocarbon-Nrf2 axis.

Meei-Ling Sheu, Cheng-Ning Yang, Liang-Yi Pan, Jason Sheehan, Liang-Yu Pan, Weir-Chiang You, Chien-Chia Wang, Ying Ju Chen, Hong-Shiu Chen, Hung-Chuan Pan.

  Microglia-mediated neuroinflammation is central to many neurological disorders. The Aryl hydrocarbon receptor (AhR) is highly expressed in microglia and plays a key role in neuroinflammation. While melatonin has anti-inflammatory effects in neurodegenerative disorders, its connection to AhR in modulating neuroinflammation is unclear. This study found that melatonin inhibits NF-κB activity, reduces pro-inflammatory mediators, and promotes an M2 microglia profile. Melatonin also enhances phospho-AhR (Tyr239) activation, increases Nrf2 expression, and decreases LPS-induced ROS generation in microglia. Melatonin's effects are similar to those achieved by AhR activation. In contrast, AhR knockout worsens neurological deficits and microglial activation, while melatonin reverses these effects by restoring AhR expression. In conclusion, effects of melatonin on microglia-mediated neuroinflammation are closely linked to phospho-AhR (Tyr239) activation and its associated downstream gene, Nrf2, via the AhR/Nrf2/ARE pathway. Therefore, melatonin, in conjunction with AhR may offer promising therapeutic benefits in neuroinflammatory disorders.

Keywords:  Aryl hydrocarbon receptors; Melatonin; Microglia; Nrf2

DOI:  https://doi.org/10.7150/ijbs.105081
Cell Commun Signal. 2025 Jul 01. 23(1): 305

Behavioral assessment and gene expression changes in a mouse model with dysfunctional STAT1 signaling.

Luca Büschgens, Nina Hempel, Aditi Methi, Andre Fischer, Nele Siering, Lars Piepkorn, Olaf Jahn, Thomas Meyer, Oliver Wirths.

   BACKGROUND: Signal transduction via the Signal Transducer and Activator of Transcription 1 (STAT1) pathway is indispensable for mediating the intracellular effects of interferon-α (IFN-α), interferon-γ (IFN-γ) and other cytokines in the brain and, thereby, crucial for antiviral and antibacterial responses during potential life-threatening CNS infections. However, the role of STAT1 signaling beyond the known IFN-α and IFN-γ effects in immediate antimicrobial defense is highly context-dependent, and studies in the existing literature using STAT1-targeted mouse models under normal physiological conditions remain scarce.
METHODS: Here, we characterized a STAT1 targeted-disruption mouse model in the absence of infectious stimuli by employing established behavioral testing paradigms and immunohistochemical stainings, as well as bulk hippocampal transcriptomic and proteomic analyses.
RESULTS: While we found neither overt behavioral alterations nor immunohistochemical changes with respect to microglial phagocytosis or proliferation, significant alterations were detected in gene and protein expression profiles implicated in neuroinflammatory processes and neuroprotection.
CONCLUSION: In summary, this study highlights the complex and context-dependent role of STAT1-mediated signaling even in the absence of any detectable behavioral and neuropathological changes.

Keywords:  Behavior; Gene expression; Interferon signaling; Mice; Proteome analysis; STAT signaling

DOI:  https://doi.org/10.1186/s12964-025-02313-w
Cell Mol Life Sci. 2025 Jun 28. 82(1): 262

NR4A2 attenuates early brain injury after intracerebral hemorrhage by promoting M2 microglial polarization via TLR4/TRAF6/NF-κB pathway inhibition.

Di Hu, Cheng Huang, Ling Tang, Jiawen Lei, Jiaqi Wang, Wenzheng Hu, Minshan Chen, Siyuan Song, Lin Lu, Pingyi Xu.

  In the early stage of intracerebral hemorrhage (ICH), rebleeding occurs when blood from the initial hematoma permeates the surrounding brain parenchyma through the disrupted blood-brain barrier (BBB), exacerbating brain injury. Neuroinflammation is a critical driver of the pathological processes underlying this phenomenon. Research on microglia near early hematomas revealed that promoting the transition of microglia to the M2 phenotype could mitigate perihematomal inflammatory damage. Recent studies have shown that the nuclear receptor-related 1 protein (NR4A2) can regulate microglial function and inhibit inflammation. However, the functions of NR4A2 in the development of ICH are still unclear. In this study, we explored the potential protective effect and mechanism of NR4A2 in ICH models. Our results demonstrated that the expression of NR4A2 was significantly decreased in both ICH rats and cell models. Increasing NR4A2 activity could effectively decrease the hematoma volume, improve the neurological prognosis and alleviate perihematomal BBB damage. In vivo and in vitro experiments revealed that NR4A2 inhibited perihematomal inflammatory damage by driving microglial polarization toward the anti-inflammatory M2 phenotype. Mechanistically, NR4A2 targeted TLR4 and inhibited the TRAF6/NF-κB pathway, thereby promoting M2 microglial polarization, reducing inflammatory cell extravasation and maintaining the integrity of the BBB. Conversely, the protective effects of NR4A2 were negated when CRX-527 (a TLR4 agonist) was introduced. These findings suggest that NR4A2 represents a promising therapeutic target for ICH.

Keywords:  Blood–brain barrier; Microglial polarization; NR4A2; Neuroinflammation; TLR4; TRAF6/NF-κB

DOI:  https://doi.org/10.1007/s00018-025-05755-0
Front Immunol. 2025 ;16 1607247

Interferons and Toxoplasma gondii shape PD-L1 regulation in retinal barrier cells: the critical role of proteases.

Benjamin Geiller, Camila Cevallos, Iuliia Tsybenko, Lydia Arnoux, Marie-Paule Felder-Schmittbuhl, Alexander W Pfaff.

   Introduction: The apicomplexan parasite Toxoplasma gondii establishes chronic infection in the central nervous system, including the retina, causing ocular toxoplasmosis (OT). This persistence relies on a fine balance between inflammatory and immunomodulatory mechanisms, especially in the immune-privileged ocular environment. We previously described the immunologic interactions between retinal cells, and particularly the roles of type I and III interferons. In this study, we investigated the regulatory dynamics of PD-L1, a central immunomodulatory receptor on immune cells.
Methods: We first investigated the mechanisms of PD-L1 regulation and the roles of type I and III interferons in an in vitro T. gondii infection model using mono- and co-culture systems of human microglia, astrocytes, and Müller cells. We also assessed PD-L1 expression in an outer blood-retina barrier model (oBRB) of differentiated retinal pigmented epithelial (RPE) cells. Additionally, we looked at retinal cell activation, PD-L1 expression and the roles of these interferons in a mouse model of OT.
Results: Our findings reveal new roles for type I and III interferons in regulating glial cell activation and PD-L1 expression in RPE, Müller, astrocytes and microglial cells. Notably, Müller cells, the most abundant glial cells in the retina, showed the highest baseline PD-L1 expression at both the mRNA and protein levels, and responded robustly to interferon stimulation. This points to a more prominent immunoregulatory role for Müller cells in the retina than previously recognized. Furthermore, we identified a parasite protease-dependent mechanism that reduces PD-L1 expression in our in vitro oBRB model potentially contributing to immune evasion and inflammation during OT. Finally, in a murine model of OT, we demonstrated that PD-L1 expression reached its peak on day 7 post-infection and that interferon neutralization plays a crucial role in regulating both PD-L1 expression and glial activation.
Discussion: The parasite T. gondii orchestrates the IFN type I and III dependent retinal immune interaction and downregulates PD-L1 in the oBRB by a protease-dependent mechanism, potentially contributing to immune evasion and inflammation in retinal infection. Our results can pave the way to fully elucidate retinal immune networks and PD-L1 regulation mechanisms, offering potential targets for therapeutic interventions in OT and other retinal inflammatory diseases.

Keywords:  PD-L1; Toxoplasma gondii; immune privilege; interferons; ocular toxoplasmosis; retina

DOI:  https://doi.org/10.3389/fimmu.2025.1607247
Comput Biol Med. 2025 Jun 27. pii: S0010-4825(25)00730-9. [Epub ahead of print]195 110379

Automated image analysis software for the study and quantification of retinal glial cells.

Miguel A Sánchez-Puebla, Lidia Sánchez-Puebla, Ana Granados, Valentín Moreno, Inés López-Cuenca, Ana I Ramírez, José M Ramírez, Juan Llorens.

  Microglia, the resident macrophages of the central nervous system, play a key role in immune surveillance, homeostasis, and neurodegenerative processes. Manual microglia analysis is time-consuming and prone to subjective bias, while most automated methods focus on quantification rather than characterization. Additionally, few tools are specifically designed for retinal microglia analysis. In this study, we present a novel automated image analysis software for microglia evaluation, integrating soma detection, quantification, characterization, skeletonization, and arborization measurement-the latter two being automated for the first time. The software was validated against expert manual annotations on 1,702 images fluorescence microscopy images of murine retinal tissue (24,559 cells), assessing its performance across both high- and low-quality images to evaluate its robustness in large-scale datasets. Our software processes images over 1,000 times faster than manual methods while maintaining high accuracy. It successfully analyzes low-quality images, though excluding them improves performance. The algorithm's ability to extract morphological features with high reproducibility enhances dataset usability, optimizing sample use and reducing animal sacrifices. This is the first tool to automate microglial skeletonization and arborization measurement, establishing a new standard for retinal microglia analysis. Its efficiency, scalability, and ability to handle varied image quality make it a valuable resource for large-scale studies. Future applications will focus on leveraging the reference values established in this study to advance neurodegenerative disease analysis, marking a significant step toward more sophisticated microglial research.

Keywords:  Arborization area calculation; Automatic image analysis; Cell quantification; Retinal microglia; Skeletonization computation; Soma characterization

DOI:  https://doi.org/10.1016/j.compbiomed.2025.110379
Acta Neuropathol Commun. 2025 Jun 28. 13(1): 141

Glial and immune dysregulation in glaucoma independent of retinal ganglion cell loss: a human post-mortem histopathology study.

Akanksha Salkar, Viswanthram Palanivel, Devaraj Basavarajappa, Mehdi Mirzaei, Angela Schulz, Peng Yan, Vivek Gupta, Stuart Graham, Yuyi You.



Keywords:  Blood‒retinal barrier; Glaucoma; Gliosis; Microglia; Retinal ganglion cell

DOI:  https://doi.org/10.1186/s40478-025-02066-0
Commun Biol. 2025 Jul 01. 8(1): 971

Opposing role of phagocytic receptors MERTK and AXL in Progranulin deficient FTD.

Claire Dudley Clelland, Li Fan, Rowan Saloner, Jon Iker Etchegaray, Chad Richard Altobelli, Sally Salomonsson, Alisha M Maltos, Aradhana Sachdev, Jingjie Zhu, Se-In Lee, Yaqiao Li, Yungui Zhou, David Le, Chao Wang, Gillian Carling, Lay Kodama, Faten Sayed, Jaun A Perez-Bermejo, Ethan G Geier, Jennifer S Yokoyama, Howie Rosen, Alissa L Nana, Salvatore Spina, Lea T Grinberg, William W Seeley, Fanny Elahi, Adam L Boxer, Michelle R Arkin, Li Gan.

Genetic mutations in the progranulin gene, GRN, cause frontotemporal dementia and a lysosomal storage disorder. Using single-nuclei RNA sequencing of the post-mortem brain tissue from adult heterozygous pathogenic granulin variant (GRN+/-) carriers we find dysregulation of microglia, phagocytosis and the phagocytic receptors MERTK and AXL. Exogenous progranulin regulates MERTK and AXL RNA expression in human microglia induced from iPSCs irrespective of GRN mutation status, without directly binding to MERTK or AXL proteins. We generated double knock-out mice and find that constitutive homozygous loss of Grn and Mertk (Grn-/-;Mertk-/-) rescued microglial disease signature while constitutive homozygous loss of Grn and Axl (Grn-/-;Axl-/-) worsened the microglial disease signature and increased lipofuscin. Lower CSF MERTK but not AXL is associated with lower progranulin levels. Furthermore, CSF MERTK is lower in symptomatic but not presymptomatic FTD patients with genetic mutations (GRN, C9ORF72, and MAPT) whereas AXL does not change between disease state and control. These data explain in part the inflammation seen in GRN-FTD and are applicable to other inflammatory states in which PGRN, MERTK and AXL play regulatory roles beyond neurodegenerative diseases. The interaction between GRN, MERTK, and AXL opens potential new therapeutic avenues to intervene on this inflammatory axis.

DOI: https://doi.org/10.1038/s42003-025-08368-2
Int Immunopharmacol. 2025 Jun 28. pii: S1567-5769(25)01123-3. [Epub ahead of print]162 115133

CCL2 activates NLRP3 inflammasomes to regulate microglial phenotype transformation to promote central sensitisation in chronic migraine.

Han Wang, Haifeng Wen, Yaying Yang, Juan Zhong, Wei Zhang, Guangcheng Qing, Dunke Zhang, Lixue Chen.

  Central sensitisation is a significant pathogenic mechanism underlying chronic migraine (CM). Mounting evidence suggests that this process is driven by central and peripheral neuroinflammation. Although increased CC motif chemokine ligand 2 (CCL2) is present in the cerebrospinal fluid (CSF) of patients with CM, whether it is a contributing factor remain unclear. In our study, we simulated CM by injecting inflammatory soup (IS) intraventricularly into rats for 7 days. Microglia expressing CD68 and CD163 were labelled with immunofluorescence staining, indicating pro and anti-inflammatory phenotypes, respectively. Enzyme-linked immunosorbent assay (ELISA) detected the cytokines interleukin (IL)-1β and IL-10, and western blotting (WB) detected Fos proto-oncogene (c-Fos) and p-extracellular signal-regulated kinase (ERK), which are markers of central sensitisation. Mechanical and thermal nociceptives were used to assess pain associated with CM. Following IS-induced modelling, protein levels of CCL2 and its receptor CCR2 increased, and CCL2 was co-localised with astrocytes while CCR2 was associated with microglia. With CCL2 recombinant protein treatment, microglia shifted to a proinflammatory phenotype with increased IL-1β and decreased IL-10 levels. In addition, central sensitisation was enhanced and mechanical and thermal pain thresholds were reduced. These adverse effects were reversed by CCL2 inhibitor and NOD-like receptor protein 3 (NLRP3) inhibitor downstream of CCL2. Significantly, MCC950 reversed the microglial phenotypic changes induced by recombinant CCL2 and attenuated central sensitisation in CM rats. These data suggest that CCL2 in the trigeminal nucleus caudalis (TNC) regulates the microglial phenotype by activating NLRP3, promoting central sensitisation of CM.

Keywords:  CCL2; Central sensitisation; Chronic migraine; Microglia; NLRP3

DOI:  https://doi.org/10.1016/j.intimp.2025.115133
ACS Chem Neurosci. 2025 Jun 28.

Phosphodiesterase 2A as a Therapeutic Target for Relieving Mechanical Allodynia and Modulating Microglial Polarization in Neuropathic Pain Models Following Spinal Cord Injury.

Wen-Jie Yang, Jie Han, Zhen-Xin Cao, Lei Yang, Jun-Nan Wang, Tao Sun.

  Spinal cord injury (SCI) is a severe clinical condition often accompanied by multiple complications, with neuropathic pain (NP) being one of the most persistent and difficult conditions to treat. The underlying mechanisms of NP remain unclear, and effective clinical treatments are lacking. Some studies suggest that phosphodiesterase 2A (PDE2A) may contribute to the development of NP. This study aims to investigate the role of PDE2A inhibitor Bay 60-7550 in alleviating NP in a rat model of SCI. Male Sprague-Dawley rats were randomly allocated into four groups: sham, SCI, SCI + Bay 60-7550, and SCI + vehicle. Mechanical thresholds were assessed using the von Frey test from 1 day prior to surgery through postoperative day 21. PDE2A expression in the spinal cord was quantified via qRT-PCR, Western blotting, and immunohistochemistry. Microglial polarization (M1/M2) was analyzed using flow cytometry and qRT-PCR. Downstream biomarkers, including IL-6, IL-1β, IL-10, TGF-β, CCL2, and CCL3, were also quantified via qRT-PCR. Additionally, enzyme-linked immunosorbent assay (ELISA) was performed to determine the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Intrathecal administration of the PDE2A inhibitor Bay 60-7550 significantly alleviated mechanical allodynia in rats following SCI. PDE2A expression was notably elevated in the spinal dorsal horn post-SCI, an effect that was suppressed by Bay 60-7550 treatment. In addition, Bay 60-7550 administration reduced the expression of pro-inflammatory cytokines (IL-6, IL-1β), increased anti-inflammatory cytokines (IL-10, TGF-β), and decreased mRNA levels of CCL2 and CCL3 in the spinal cord. Consistently, treatment with Bay 60-7550 elevated the levels of cGMP and cAMP in the spinal cord and shifted microglial polarization by increasing the proportion of M2-type cells while reducing M1-type cells in SCI rats. Inhibiting PDE2A overexpression may mitigate the progression of NP in rats following SCI by modulating microglial polarization. Therefore, PDE2A represents a promising therapeutic target for the management of neuropathic pain after SCI.

Keywords:  microglia; neuropathic pain; phosphodiesterase 2A; polarization; spinal cord injury

DOI:  https://doi.org/10.1021/acschemneuro.5c00169
Mol Neurobiol. 2025 Jul 03.

Mbnl1 Protects Against Cerebral Ischemia-Reperfusion Injury by Modulating Microglia/Macrophage Polarization via NF-κB Pathway.

Wenting Xu, Mengjia Zhou, Linlin Li, Yuqing Zhang, Tianya Zhang, Xiangjian Zhang.

  Activated and polarized microglia regulate neuroinflammatory responses and programmed cell death processes in ischemic stroke. Although the inactivation of muscleblind-like 1 (Mbnl1) is known to cause structural defects in the brain, its role in microglial apoptosis and polarization remains unclear. This study aims to explore the mechanism of Mbnl1 in ischemic stroke, particularly its role in the regulation of microglial apoptosis and polarization, as well as its impact on neuroinflammatory responses and cognitive dysfunction. The expression level of Mbnl1 in the serum of stroke patients was determined. Furthermore, Mbnl1 was overexpressed in a C57BL/6N stroke model and an oxygen-glucose deprivation model in BV-2 cells. Changes in relevant marker proteins were detected using histological assays, cognitive function tests, enzyme-linked immunosorbent assay for inflammatory factor detection, flow cytometry for apoptosis assessment, immunofluorescence, and Western blot analysis. The expression level of Mbnl1 in the serum of stroke patients was determined. Furthermore, Mbnl1 was overexpressed in a C57BL/6N stroke model and an oxygen-glucose deprivation model in BV-2 cells. Changes in relevant marker proteins were detected using histological assays, cognitive function tests, enzyme-linked immunosorbent assay for inflammatory factor detection, flow cytometry for apoptosis assessment, immunofluorescence, and Western blot analysis. Mbnl1 overexpression exerts a protective effect against ischemic stroke by regulating microglia-mediated neuroinflammation through inhibition of the NF-κB signaling pathway. This modulation promotes cognitive recovery in C57BL/6N mice with stroke, highlighting Mbnl1 as a potential therapeutic target for stroke treatment.

Keywords:  Ischemic stroke; Mbnl1; Microglia; Neurologic dysfunction

DOI:  https://doi.org/10.1007/s12035-025-05180-1
Vaccine. 2025 Jul 02. pii: S0264-410X(25)00748-0. [Epub ahead of print]61 127451

mRNA vaccination mitigates pathological retinochoroidal neovascularization in animal models.

Yasuo Yanagi, Hinako Ichikawa, Le Bui Thao Nguyen, Akimasa Hayashi, Naoko Abe, Hiroshi Abe, Satoshi Uchida.

Retinochoroidal neovascularization (NV), involved in macular degeneration, diabetic retinopathy, and other ocular diseases, causes vision impairment and blindness. Current treatments rely on repeated intraocular injections of anti-angiogenic drugs, which are burdensome for patients and clinicians, and some patients fail to respond to the treatments. This study investigates the potential of mRNA vaccination to mitigate NV and treat ocular pathologies. The vaccine targets leucine-rich alpha-2-glycoprotein 1 (LRG1), a protein specifically expressed in pathological neovascularization, inducing anti-LRG1 antibody responses in mice. In a laser-induced NV model, the LRG1 mRNA vaccine reduces NV area and leakage while inhibiting microglial cell infiltration. Histological analysis shows no adverse effects on retinal architecture or glial cell activation. Additionally, in Vldlr knockout mice, LRG1 mRNA administration suppresses ongoing neovascularization and downregulates key angiogenic mediators. These findings highlight the therapeutic potential of LRG1 mRNA as a novel strategy for CNV-associated diseases.

DOI: https://doi.org/10.1016/j.vaccine.2025.127451