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At least 19 recordsLinked to original sources

PubMed2017

Ischemia/Reperfusion Induces Interferon-Stimulated Gene Expression in Microglia.

Innate immune signaling is important in the pathophysiology of ischemia/reperfusion (stroke)-induced injury and recovery. Several lines of evidence support a central role for microglia in these processes. Recent work has identified Toll-like receptors (TLRs) and type I interferon (IFN) signaling in both ischemia/reperfusion-induced brain injury and ischemic preconditioning-mediated neuroprotection. To determine the effects of "ischemia/reperfusion-like" conditions on microglia, we performed genomic analyses on wild-type (WT) and TLR4-/- cultured microglia after sequential exposure to hypoxia/hypoglycemia and normoxia/normoglycemia (H/H-N/N). We observed increased expression of type 1 IFN-stimulated genes (ISGs) as the predominant transcriptomal feature of H/H-N/N-exposed WT, but not TLR4-/-, microglia. Microarray analysis on ex vivo sorted microglia from ipsilateral male mouse cortex after a transient in vivo ischemic pulse also demonstrated robust expression of ISGs. Type 1 IFNs, including the IFN-αs and IFN-β, activate the interferon-α/β receptor (IFNAR) complex. We confirmed both in vitro H/H-N/N- and in vivo ischemia/reperfusion-induced microglial ISG responses by quantitative real-time PCR and demonstrated that both were dependent on IFNAR1. We characterized the effects of hypoxia/hypoglycemia on phosphorylation of signal transducer and activator of transcription 1 (STAT1), release of type 1 IFNs, and surface expression of IFNAR1 in microglia. We demonstrated that IFN-β induces dose-dependent secretion of ISG chemokines in cultured microglia and robust ISG expression in microglia both in vitro and in vivo Finally, we demonstrated that the microglial ISG chemokine responses to TLR4 agonists were dependent on TLR4 and IFNAR1. Together, these data suggest novel ischemia/reperfusion-induced pathways for both TLR4-dependent and -independent, IFNAR1-dependent, type 1 IFN signaling in microglia.SIGNIFICANCE STATEMENT Stroke is the fifth leading cause of death in the United States and is a leading cause of serious long-term disability worldwide. Innate immune responses are critical in stroke pathophysiology, and microglia are key cellular effectors in the CNS response to ischemia/reperfusion. Using a transcriptional analysis approach, we identified a robust interferon (IFN)-stimulated gene response within microglia exposed to ischemia/reperfusion in both in vitro and in vivo experimental paradigms. Using a number of complementary techniques, we have demonstrated that these responses are dependent on innate immune signaling components including Toll-like receptor-4 and type I IFNs. We have also elucidated several novel ischemia/reperfusion-induced microglial signaling mechanisms.

Animals↗

PubMed2025

Lymphoid gene expression supports neuroprotective microglia function.

Microglia, the innate immune cells of the brain, play a defining role in the progression of Alzheimer's disease (AD)1. The microglial response to amyloid plaques in AD can range from neuroprotective to neurotoxic2. Here we show that the protective function of microglia is governed by the transcription factor PU.1, which becomes downregulated following microglial contact with plaques. Lowering PU.1 expression in microglia reduces the severity of amyloid disease pathology in mice and is linked to the expression of immunoregulatory lymphoid receptor proteins, particularly CD28, a surface receptor that is critical for T cell activation3,4. Microglia-specific deficiency in CD28, which is expressed by a small subset of plaque-associated PU.1low microglia, promotes a broad inflammatory microglial state that is associated with increased amyloid plaque load. Our findings indicate that PU.1low CD28-expressing microglia may operate as suppressive microglia that mitigate the progression of AD by reducing the severity of neuroinflammation. This role of CD28 and potentially other lymphoid co-stimulatory and co-inhibitory receptor proteins in governing microglial responses in AD points to possible immunotherapy approaches for treating the disease by promoting protective microglial functions.

Microglia↗

PubMed1979

Transformation of monocytes into amoeboid microglia in the corpus callosum of postnatal rats, as shown by labelling monocytes by carbon particles.

Two successive intravenous doses of carbon suspension were given at 24 hourly intervals into six days old rats. These animals were killed at intervals ranging from 1 to 9 days after the second injection. The corpus callosum and neighbouring structures were examined for cells containing ingested colloidal carbon particles in their cytoplasm. Twenty four hours after the second injection, a variable number of carbon-labelled monocytes were adherent to the luminal wall of blood vessels in the corpus callosum. Numerous carbon-labelled cells appeared to have left the lumen and entered the brain tissue surrounding the vessels. These perivascular carbon-labelled monocytes in the neuropil displayed a large pale nucleus with fine chromatin granules. The phagocytic amoeboid microglia in the corpus callosum were unlabelled at first, although a few cells of a similar nature in the cavum septi pellucidi did show carbon particles in their cytoplasm. Four or five days after the second carbon injection perivascular carbon-labelled monocytes were rare, but carbon particles were now present in the amoeboid microglia. At 8 days amoeboid microglia were virtually absent from the corpus callosum but carbon particles now appeared in cells which closely resembled microglia (flattened nucleus, coarse chromatin, scanty cytoplasm at one pole). The sequential appearance of carbon particles in monocytes, amoeboid microglia, and microglia, suggests that monocytes transform into microglia by way of an amoeboid microglial stage.

Aging↗

PubMed2025

Inhaled xenon modulates microglia and ameliorates disease in mouse models of amyloidosis and tauopathy.

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder. Antiamyloid antibody treatments modestly slow disease progression in mild dementia due to AD. Emerging evidence shows that homeostatic dysregulation of the brain immune system, especially that orchestrated by microglia, plays an important role in disease onset and progression. Thus, a major question is how to modulate the phenotype and function of microglia to treat AD. Xenon (Xe) gas is a noble gas used in human patients as an anesthetic and a neuroprotectant used for treating brain injuries. Xe penetrates the blood-brain barrier, which could make it an effective therapeutic. To assess the effect of Xe on microglia and AD pathology, we designed a custom Xe inhalation chamber and treated several mouse models of AD with Xe gas. Xe treatment induced mouse microglia to adopt an intermediate activation state that we have termed pre-neurodegenerative microglia (pre-MGnD). This microglial phenotypic transition was observed in mouse models of acute neurodegeneration and amyloidosis (APP/PS1 and 5xFAD mice) and tauopathy (P301S mice). This microglial state enhanced amyloid plaque compaction and reduced dystrophic neurites in the APP/PS1 and 5xFAD mouse models. Moreover, Xe inhalation reduced brain atrophy and neuroinflammation and improved nest-building behavior in P301S mice. Mechanistically, Xe inhalation induced homeostatic brain microglia toward a pre-MGnD state through IFN-γ signaling that maintained the microglial phagocytic response in APP/PS1 and 5xFAD mice while suppressing the microglial proinflammatory phenotype in P301S mice. These results support the translation of Xe inhalation as an approach for treating AD.

Animals↗

PubMed2024

Analysis of different expression RNA binding protein genes in mouse microglia cell from the brains of mice 72 h after subarachnoid hemorrhage or sham operation.

BACKGROUND: The prognosis of brain injury caused by subarachnoid hemorrhage (SAH) is poor. Previous studies showed that abnormal function of RBPs might be involved in brain injury, neuroinflammation and further affect microglia homeostasis. However, no studies have systematically analyzed the genome-wide abnormal expression of RBPs genes in microglia during SAH. METHODS: RNA-seq data of microglia from the SAH mouse group (SAH) and control sham-operated mouse group (sham) were downloaded from the GEO database in GSE167957, including four samples from the sham group and four samples from the SAH group for subsequent analysis.Utilizing GO and KEGG functional enrichment analyses, we conducted a comprehensive study of differentially expressed genes (DEGs), alternative splicing patterns, and co-expression networks to gain deeper insights into the differential expression of RNA-binding proteins (RBPs) and differential alternative splicing events (ASEs) between the SAH (subarachnoid hemorrhage) and sham groups. This analysis aimed to elucidate the potential mechanisms underlying the aberrant expression of RBPs in microglia during brain injury caused by SAH. RESULTS: ASEs and co-expression analyses of differentially expressed RBPs and differential ASEs were carried out in microglia in terms of gene expression. GO and KEGG functional enrichment analysis showed that aberrantly expressed RBPs such as Mcm7, Mtdh, SRSF3, and Hnrnpa2b1 may affect and regulate downstream Csnk1d, Uckl1 and other protein phosphorylation-related genes by alterative splicing. CONCLUSION: RBPs were aberrantly expressed in microglia during the development of brain injury secondary to SAH, regulating alterative splicing of downstream genes and influencing the progression of SAH brain injury in this study. This implies that RBPs are important for the identification of new therapeutic targets for brain injury after SAH.

Animals↗

PubMed2026

A reproducible three-dimensional model of human brain tissue to investigate physiological and disease-associated microglia phenotypes.

Stem-cell-based in vitro models offer promising potential to elucidate human brain cell functions and interactions, but limitations in reproducibility, maturation and cell-type diversity persist. Especially, prolonged incorporation of mature microglia and studies of neuroinflammation have proven challenging. Here, we developed a human induced pluripotent stem cell-based three-dimensional cortical brain tissue model (3BTM) containing neurons, astrocytes and microglia with high reproducibility, maturity and viability. 3BTMs show morphological, functional and proteomic maturation of all cell types, leading to high similarity to their in vivo counterparts. Incorporated microglia survive for over 6 months and display mature morphology, functions and gene expression. Importantly, when engineered to model Alzheimer's disease pathology, 3BTMs recapitulate key disease hallmarks, including amyloid deposition, increased phospho-tau levels and neuroinflammation, with microglia shifting their transcriptional landscape to disease-relevant signatures. Treatment of Alzheimer's disease 3BTMs with anti-Aβ immunotherapy cleared deposits and largely reversed disease signatures in glia. Together, our microglia-containing model provides a platform for studying physiological and pathological states of human brain tissue.

Humans↗

PubMed2025

A xeno-free protocol for rapid differentiation of human iPSC-derived microglia from the KOLF2.1J reference line.

We present a detailed, xeno-free protocol for the rapid differentiation of human induced pluripotent stem cells (hiPSCs) into microglia using the well-characterized KOLF2.1J reference line. This system employs doxycycline-inducible expression of six transcription factors (6-TF), stably integrated into the CLYBL safe harbor locus, to drive uniform microglial differentiation within two weeks. Adapted from Dräger et al. (1), our protocol includes key optimizations for KOLF2.1J, including culture on Laminin-521 to support xeno-free conditions. The resulting i-Microglia exhibit hallmark features of mature microglia, including expression of P2RY12, loss of the pluripotency marker SSEA4, phagocytic activity, and upregulation of immune markers (e.g., CD80, CD83) upon LPS stimulation. We also demonstrate compatibility with co-culture systems using iPSC-derived neurons. Additionally, we describe a modification of the line to include a constitutive mCherry reporter integrated into the SH4-2 safe harbor locus, enabling fluorescent tracking of microglia in mixed cultures or in vivo. This protocol provides a reproducible and scalable platform for generating functional human microglia from a widely used hiPSC line, supporting applications in disease modeling, neuroinflammation research, and therapeutic screening.

Journal Article↗

PubMed2026

Comparative lipidomics of iPSC-derived microglia protocols reveal lipid droplet and immune differences mediated by media composition.

Altered microglial lipid metabolism is heavily implicated in Alzheimer's disease (AD) and aging. Recently, protocols were developed to generate human induced pluripotent stem cell-derived microglia-like cells (iMGL) to study microglial function in vitro, including embryoid body-based methods and induced transcription factor (iTF)-dependent approaches. Here, we performed comparative lipidomics on iMGL from these methods and report major differences in multiple lipid classes, including triglycerides (TGs), a storage form of fatty acids implicated in microglial reactivity. TGs are strongly increased in iTF microglia due to the absence of a media supplement (B-27). Supplementing iTF microglia with B-27, or its component L-carnitine, reduces TGs and promotes a homeostatic state. B-27 also renders iTF microglia metabolically responsive to immune stimuli. Overall, our data show that iMGL differentiation methods have a major impact on microglial lipidomes and warrant attention when studying AD and neuroinflammatory processes involving lipids.

Microglia↗

PubMed2026

FPR2/ALX stimulation modulates microglia and natural killer cells to restrict autoimmune astrocytopathy.

Autoantibody- and complement-mediated cytotoxicity can cause autoimmune astrocytopathy that leads to CNS inflammatory demyelination. Formyl peptide receptor 2 (FPR2/ALX) governs the activation and propagation of immune response. However, the precise role of FPR2/ALX in neuroinflammation and the effect of FPR2/ALX stimulation on autoimmune astrocytopathy are poorly understood. Using a mouse model of autoimmune astrocytopathy induced by AQP4-IgG- and complement-mediated cytotoxicity, we found that the stimulation of FPR2/ALX with the small-molecule agonist Quin-C1 led to reduced brain lesion volume, astrocyte loss and demyelination. This was accompanied by enhanced anti-inflammatory activity of microglia and reduced infiltration of lymphocytes in the brain. FPR2/ALX stimulation also led to increased phosphorylation of SYK and AKT in mice with autoimmune astrocytopathy. Notably, the benefits of FPR2/ALX stimulation were attenuated in mice with autoimmune astrocytopathy after microglial depletion using the CSF1R inhibitor PLX5622 or natural killer (NK) cell depletion using an anti-NK1.1 monoclonal antibody. Additionally, the protective effects of FPR2/ALX stimulation were diminished in mice with autoimmune astrocytopathy that received the SYK inhibitor R406. Collectively, our findings demonstrate that FPR2/ALX stimulation may represent a promising therapeutic strategy to attenuate detrimental neuroinflammation in autoimmune astrocytopathy by modulating microglia and NK cells. FPR2/ALX stimulation suppresses autoimmune astrocytopathy: Using a mouse model of autoimmune astrocytopathy, we demonstrated that FPR2/ALX stimulation with the small molecule Quin-C1 reduces the CNS infiltration of lymphocytes and augments the anti-inflammatory activity of microglia, leading to attenuated astrocyte pathology induced by AQP4-IgG and complement-mediated attacks. Mechanistically, the benefits of FPR2/ALX stimulation using Quin-C1 involve microglia, natural killer (NK) cells, and SYK-AKT signaling.

Animals↗

PubMed2024

Gene expression profiles of endothelium, microglia and oligodendrocytes in hippocampus of post-stroke depression rat at single cell resolution.

Post-stroke depression (PSD) is a common but severe mental complication after stroke. However, the cellular and molecular understanding of PSD is still yet to be illustrated. In current study, we prepared PSD rat model (MD) via unilateral middle cerebral artery occlusion (MCAO) and chronic stress stimulation (DEPR), and isolated hippocampal tissues for single cell sequencing of 10x Genomics Chromium. First, we determined the presence of the increased cell population of endothelium and microglia and the compromised oligodendrocytes in MD compared to NC, MCAO and DEPR. The enriched functions of highly variable genes (HVGs) of endothelium and microglia suggested a reinforced blood-brain barrier in MD. Next, cell clusters of endothelium, microglia and oligodendrocytes were individually analyzed, and the subtypes with distinct functions were identified. The presence of expression profiles, intercellular communications and signaling pathways of these three cell populations of PSD displayed a similar but more aggressive appearance with DEPR compared to MCAO and NC. Taken together, this study characterized the specific gene profile of endothelium, microglia and oligodendrocytes of hippocampal PSD by single cell sequencing, emphasizing the crosstalk among them to provide theoretical basis for the in-depth mechanism research and drug therapy of PSD.

Animals↗

PubMed1978

Initial response of silver-impregnated "resting microglia" to stab wounding in rabbit hippocampus.

Adult rabbits received stab wound in the cerebrum and were sacrificed at intervals of 20, 30, and 39 h thereafter. Each animal was injected intracerebrally with 3H-thymidine 2h before fixation. Altered brain tissues of the stratum radiatum of hippocampus were taken for examination. Response of "resting microglia" to stab wounding was investigated by electron microscopic autoradiography and by autoradiography applied on silver-impregnated materials. Following results were obtained: (1) Resting microglia undergo marked swelling shortly after the brain damage. We designate these cells as "swollen microglia". (2) Swollen microglia form the only cell population that proliferate actively in the initial stage of glial response to the brain injury, and (3) astroglia do not proliferate during the same experimental periods, in the rabbit hippocampus.

Animals↗

PubMed2026

Single-nucleus transcriptomics reveals cell type-specific remodeling and epilepsy-associated microglia.

Temporal lobe epilepsy (TLE) is the most common acquired epilepsy, causing refractory seizures and cognitive deficits. We performed single-nucleus RNA sequencing on hippocampal tissue from mice 3 and 6 weeks following pilocarpine-induced status epilepticus, a robust model of TLE. Epilepsy samples showed reductions in Cck and Lamp5-Lhx6 interneuron subclusters, alongside increases in Cajal-Retzius cells, dentate granule (DG) cell precursors, and a mature DG cell subcluster. Among glia, an astrocyte subcluster and a markedly expanded microglia sublcuster were increased. We term this microglia population epilepsy-associated microglia (EAM). The transcriptomic profile of EAM overlaps with microglia described in models of Alzheimer's disease and traumatic brain injury, including enrichment of Myo1e and Igf1. EAM display amoeboid morphology, can be found in clumps around pyramidal and granule cell body layers, and exhibit enlarged vesicles and mitochondria. Cell-cell interaction analysis predicts DG cells as their primary interaction partners. This dataset defines transcriptomic programs underlying key cellular alterations in TLE, enabling mechanistic dissection of epileptogenesis.

TLE↗

PubMed2026

Regulators of interferon-responsive microglia uncovered by Genome-wide CRISPRi screening.

Microglia dynamically support brain health through the induction of specialized activation states in response to injury or disease. Activation of the interferon-responsive microglia (IRM) state has been identified across neurodevelopmental windows, age-related cognitive decline, and neurodegenerative diseases. Functionally, IRM have been linked to synaptic pruning, dead cell removal, and neuroinflammation, making this state critical to brain homeostasis. While the functional importance of this state is becoming increasingly clear, our understanding of the regulatory networks that govern IRM induction remain incomplete. To systematically identify genetic regulators of the IRM state, we conducted a genome-wide CRISPR interference screen in human iPSC-derived microglia using IFIT1 as a representative IRM marker. We identified 772 genes that modulate IRM, including canonical type I interferon signaling genes (IFNAR2, TYK2, STAT1/2, USP18) and newly described regulators. We uncovered a non-canonical role for the CCR4-NOT transcription complex subunit 10, CNOT10, in IRM activation. This work provides a comprehensive resource that can be applied to dissect the functions of interferon-responsive microglia and highlights both established and novel targets for modulating microglial interferon signaling in health and disease.

Computational biology and bioinformatics↗

PubMed1979

Immunological analysis of human microglia: lack of monocytic and lymphoid membrane differentiation antigens.

While it is certain that reactive microglia (phagocytes in damaged brain tissue) originate from monocytes, the derivation of resting microglia (argentophilic cells in undamaged brain tissue) is not clear. In order to examine a possible lymphocytic and/or monocytic origin for resting microglia, cryostat sections of presumably normal human brain tissue were treated with anti-lymphocyte, anti-monocyte and anti-beta 2-microglobulin sera and then stained with the immunoperoxidase technique. No positive reaction was obtained. It must be concluded that resting microglia are not derived from mononuclear blood cells.

Antigens, Surface↗

PubMed2026

Human IL-34 Deficiency Primes Microglia Toward Alzheimer's Disease-Associated States.

BACKGROUND: Genome-wide association studies (GWAS), with independent replication in large European consortia, have identified a common nonsense variant in IL-34 (Y213X) as a genetic risk factor for late-onset Alzheimer's disease (AD). However, the biological consequences of this IL-34 mutation in humans, its prevalence in the population, and the mechanisms by which IL-34-Y213X alters microglial homeostasis, cerebrospinal fluid (CSF) proteomic networks, and amyloid pathology remain poorly understood. METHODS: We combined human genetics, cerebrospinal fluid (CSF) and serum proteomics, transcriptomics, large-scale phenome-wide association analyses, and preclinical experimental models to define the impact of human IL-34 deficiency. IL-34 concentrations were first quantified in CSF and serum from deeply phenotyped AD cohorts stratified by the common IL-34-Y213X nonsense variant. IL-34 levels and IL-34-Y213X status were then integrated with unbiased CSF proteomic networks and AD biomarkers. Transcriptomic profiling of purified microglia from IL-34 knockout mice was performed to assess disease-associated microglial programs. Using APP/PS1 mice lacking IL-34, we examined the effects of IL-34 deficiency on microglial survival, tiling, and plaque encapsulation. Finally, we performed postmortem analyses of temporal cortex from AD patients carrying IL-34-Y213X to assess microglial density, spatial organization, and plaque-associated responses. FINDINGS: IL-34-Y213X was a strong, dose-dependent loss-of-function (LOF) allele that reduced IL-34 levels by up to 2.5 standard deviations in CSF and serum and was common in multiple populations. IL-34 deficiency reshaped CSF proteomic networks, downregulating axon guidance and microglial support modules while upregulating inflammatory and extracellular matrix signatures, and showed pleiotropic associations with neurological, inflammatory, and metabolic traits. Transcriptomic analysis of sorted microglia from healthy 9-month-old IL-34KO compare to wild-type mice revealed a profound pro-inflammatory and disease-associated microglial transcriptional program enriched for disease-associated microglia (DAM) signatures, inflammatory pathways, and AD risk genes including APOE, CLU, and CASS4. In APP/PS1 mice, genetic IL-34 deletion selectively depleted homeostatic gray-matter microglia, disrupted microglial tiling, and impaired plaque encapsulation, resulting in altered amyloid structure and enhancing neuritic injury. Concordantly, AD patients homozygous for IL-34-Y213X displayed markedly reduced cortical microglial density and increased microglial spatial dispersion, indicating a breakdown of the microglial network organization in the human brain. INTERPRETATION: A common human IL-34 LOF variant creates a naturally occurring model of IL-34 deficiency that links microglial survival, CSF network signatures, and amyloid pathology in both mice and humans. Importantly, IL-34 deficiency alone is sufficient to induce inflammatory, AD-associated microglial states beyond simply reducing microglial number. These findings identify IL-34/CSF1R signaling as a critical determinant of microglial resilience and a potential upstream pathway linking human genetic variation to AD susceptibility, highlighting IL-34-dependent pathways as promising targets for disease modification. FUNDING: This work was supported by grants from the Spanish Ministerio de Ciencia, Innovación y Universidades/FEDER/UE (PID2024-157400OB-I00) and FORTALECE program (FORT23/00008; Instituto de Salud Carlos III, Spain) to RRL and JLV, ISCIII of Spain co-financed by FEDER funds (European Union) through grants PI24/00308 (JV) and CIBERNED collaborative grant 2022/01 to JV, PID2023-147125OB-I00 and CEX2023-001386-S (Severo Ochoa Programme) to SMTBC. A.R. is supported by STAR Award. University of Texas System. Tx, United States, The South Texas ADRC. National Institute of Aging. National Institutes of Health. USA. (P30AG066546), the Keith M. Orme and Pat Vigeon Orme Endowed Chair in Alzheimer's and Neurodegenerative Diseases (2024-2025) and Patricia Ruth Frederick Distinguished Chair for Precision Therapeutics in Alzheimer's and Neurodegenerative Diseases (2025-2028). AR is also supported by the Agency for Innovation and Entrepreneurship (VLAIO) grant N° PR067/21 for the HARPONE project and the ADAPTED project the EU/EFPIA Innovative Medicines Initiative Joint Undertaking Grant N° 115975 and CIBERNED (ISCIII).

Journal Article↗

PubMed2026

Transcriptomic landscape of microglia in mouse models of social dysfunction and oxytocin-mediated recovery.

Atypical sociability is a hallmark of neurodevelopmental disorders arising from genetic susceptibility and prenatal environmental perturbations that can affect diverse brain cell types. Using single-cell transcriptomics, we previously identified selective vulnerability of parvocellular oxytocin (OT) neurons in the paraventricular hypothalamus (PVH) following embryonic exposure to valproic acid (VPA), a teratogen that induces social deficits. Neonatal chemogenetic activation of OT neurons rescued these behavioral abnormalities and partially restored dysregulated gene expression. However, the effects of VPA exposure and OT neuron stimulation on non-neuronal PVH cells remained unclear. Here, we show that VPA induces transcriptional abnormalities in PVH microglia. Spatial transcriptomics revealed altered distributions of PVH microglial subtypes. Notably, neonatal OT neuron stimulation reversed a subset of VPA-induced microglial gene downregulation, while pharmacological manipulation of microglia normalized aberrant OT gene expression in putative parvocellular OT neurons. These findings support bidirectional OT neuron-microglia interactions that may underlie social dysfunction following embryonic VPA exposure.

autism spectrum disorder↗

PubMed2025

Targeting phagocytosis for amyloid-β clearance: implications of morphology remodeling and microglia activation probed by bifunctional chimaeras.

Amyloid-β (Aβ), a key driver of Alzheimer's disease (AD) pathogenesis, possesses diverse harmful and clearance-resistant structures that present substantial challenges to therapeutic development. Here, we demonstrate that modulating Aβ morphology, rather than Toll-like receptor 2 (TLR2)-dependent microglia activation, is essential for effective phagocytosis of Aβ species by microglia. By developing a bifunctional mechanistic probe (P2CSKn) designed to remodel Aβ and activate TLR2, we show it restructures soluble Aβ (sAβ) and fibrillar Aβ (fAβ) into less toxic hybrid aggregates (hPAβ). Critically, this structural remodeling protects microglia from Aβ toxicity while enabling robust phagocytosis. Moreover, although TLR2 activation mildly enhances Aβ uptake, it concurrently triggers detrimental inflammation that negates its benefits. Our findings establish morphological remodeling as the critical determinant of effective Aβ clearance and suggest a morphology-focused strategy for developing safe therapeutics for Aβ-related diseases.

Microglia↗

PubMed1977

Electron microscopic features of the resting microglia in the rabbit hippocampus, identified by silver carbonate staining.

Vibratome sections of hippocampus of adult rabbits were stained by a modified Hortega's silver-carbonate method. Impregnated materials were examined by electron microscopy to decide fine-structural characteristics of the resting microglia. Comparing their characteristics with those of macrophages, we came to the following conclusions: (1) Impregnated resting microglia in the hippocampus of adult rabbits can be identified as cells having distinct fine structures. (2) Resting microglia are morphologically different from macrophages or their precursor cells, and, therefore, seem not to be hematogenous cells sojourning in the normal brain parenchyma.

Animals↗