RESUMEN
Ischaemic stroke is a common condition that can lead to cerebral ischaemia-reperfusion injury. Phillygenin (PHI), a natural bioactive compound derived from Forsythia suspensa, has been shown to play a crucial role in regulating inflammation across various diseases. However, its specific regulatory effects in ischaemic stroke progression remain unclear. In this study, we established a middle cerebral artery occlusion (MCAO) rat model. Treatment with PHI (50 or 100 mg/kg) significantly reduced cerebral infarction in MCAO rats. PHI treatment also mitigated the increased inflammatory response observed in these rats. Additionally, PHI suppressed microglial activation by reducing iNOS expression, a marker of M1-type polarization of microglia, and attenuated increased brain tissue apoptosis in MCAO rats. Furthermore, PHI's anti-inflammatory effects in MCAO rats were abrogated upon co-administration with GW9662, a peroxisome proliferator-activated receptor γ (PPARγ) inhibitor. In summary, PHI attenuated microglial activation and apoptosis in cerebral ischaemia-reperfusion injury through PPARγ activation, suggesting its potential as a therapeutic agent for mitigating cerebral ischaemia-reperfusion injury.
Asunto(s)
Apoptosis , Infarto de la Arteria Cerebral Media , Microglía , PPAR gamma , Ratas Sprague-Dawley , Daño por Reperfusión , Animales , PPAR gamma/metabolismo , Apoptosis/efectos de los fármacos , Daño por Reperfusión/tratamiento farmacológico , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Ratas , Masculino , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Infarto de la Arteria Cerebral Media/patología , Infarto de la Arteria Cerebral Media/metabolismo , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , LignanosRESUMEN
Parkinson's Disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the Substantia nigra pars compacta (SNpc). Apoptosis is thought to play a critical role in the progression of PD, and thus understanding the effects of antiapoptotic strategies is crucial for developing potential therapies. In this study, we developed a unique genetic model to selectively delete Casp3, the gene encoding the apoptotic protein caspase-3, in dopaminergic neurons (TH-C3KO) and investigated its effects in response to a subacute regime of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration, which is known to trigger apoptotic loss of SNpc dopaminergic neurons. We found that Casp3 deletion did not protect the dopaminergic system in the long term. Instead, we observed a switch in the cell death pathway from apoptosis in wild-type mice to necrosis in TH-C3KO mice. Notably, we did not find any evidence of necroptosis in our model or in in vitro experiments using primary dopaminergic cultures exposed to 1-methyl-4-phenylpyridinium in the presence of pan-caspase/caspase-8 inhibitors. Furthermore, we detected an exacerbated microglial response in the ventral mesencephalon of TH-C3KO mice in response to MPTP, which mimicked the microglia neurodegenerative phenotype (MGnD). Under these conditions, it was evident the presence of numerous microglial phagocytic cups wrapping around apparently viable dopaminergic cell bodies that were inherently associated with galectin-3 expression. We provide evidence that microglia exhibit phagocytic activity towards both dead and stressed viable dopaminergic neurons through a galectin-3-dependent mechanism. Overall, our findings suggest that inhibiting apoptosis is not a beneficial strategy for treating PD. Instead, targeting galectin-3 and modulating microglial response may be more promising approaches for slowing PD progression.
Asunto(s)
Apoptosis , Caspasa 3 , Neuronas Dopaminérgicas , Galectina 3 , Microglía , Necrosis , Fagocitosis , Animales , Neuronas Dopaminérgicas/metabolismo , Neuronas Dopaminérgicas/efectos de los fármacos , Neuronas Dopaminérgicas/patología , Microglía/metabolismo , Microglía/patología , Microglía/efectos de los fármacos , Apoptosis/efectos de los fármacos , Galectina 3/metabolismo , Galectina 3/genética , Caspasa 3/metabolismo , Ratones , Fagocitosis/efectos de los fármacos , Ratones Noqueados , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/farmacología , Ratones Endogámicos C57BL , MasculinoRESUMEN
Traumatic brain injury (TBI) affects millions globally, with a majority of TBI cases being classified as mild, in which diffuse pathologies prevail. Two of the pathological hallmarks of TBI are diffuse axonal injury (DAI) and microglial activation. While progress has been made investigating the breadth of TBI-induced axonal injury and microglial changes in rodents, the neuroinflammatory progression and interaction between microglia and injured axons in humans is less well understood. Our group previously investigated microglial process convergence (MPC), in which processes of non-phagocytic microglia directly contact injured proximal axonal swellings, in rats and micropigs acutely following TBI. These studies demonstrated that MPC occurred on injured axons in the micropig, but not in the rat, following diffuse TBI. While it has been shown that microglia co-exist and interact with injured axons in humans post-TBI, the occurrence of MPC has not been quantitatively measured in the human brain. Therefore, in the current study we sought to validate our pig findings in human postmortem tissue. We investigated MPC onto injured axonal swellings and intact myelinated fibers in cases from individuals with confirmed DAI and control human brain tissue using multiplex immunofluorescent histochemistry. We found an increase in MPC onto injured axonal swellings, consistent with our previous findings in micropigs, indicating that MPC is a clinically relevant phenomenon that warrants further investigation.
Asunto(s)
Axones , Lesión Axonal Difusa , Microglía , Humanos , Microglía/patología , Microglía/metabolismo , Axones/patología , Axones/metabolismo , Animales , Masculino , Porcinos , Lesión Axonal Difusa/patología , Lesión Axonal Difusa/metabolismo , Femenino , Encéfalo/patología , Encéfalo/metabolismo , Lesiones Traumáticas del Encéfalo/patología , Lesiones Traumáticas del Encéfalo/metabolismo , Persona de Mediana Edad , Autopsia , Adulto , Anciano , RatasRESUMEN
Glutaminyl cyclase (QC) and its isoenzyme (isoQC) catalyze the formation of N-terminal pyroglutamate (pGlu) from glutamine on a number of neuropeptides, peptide hormones and chemokines. Chemokines of the C-C ligand (CCL) motif family are known to contribute to inflammation in neurodegenerative conditions. Here, we used a model of transient focal cerebral ischemia to explore functional, cellular and molecular responses to ischemia in mice lacking genes for QC, isoQC and their substrate CCL2. Mice of the different genotypes were evaluated for functional consequences of stroke, infarct volume, activation of glia cells, and for QC, isoQC and CCL2 expression. The number of QC-immunoreactive, but not of isoQC-immunoreactive, neurons increased robustly in the infarct area at 24 and 72 h after ischemia. In parallel, immunohistochemical signals for the QC substrate CCL2 increased from 24 to 72 h after ischemia induction without differences between genotypes analyzed. The increase in CCL2 was accompanied by morphological activation of Iba1-immunoreactive microglia and recruitment of MHC-II-positive cells at 72 h after ischemia. Among other chemokines quantified in the brain tissue, CCL17 showed higher concentrations at 72 h compared to 24 h after ischemia. Collectively, these data suggest a critical role for QC in inflammatory processes in the stroke-affected brain.
Asunto(s)
Aminoaciltransferasas , Isquemia Encefálica , Inflamación , Animales , Aminoaciltransferasas/metabolismo , Aminoaciltransferasas/genética , Ratones , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Isquemia Encefálica/genética , Inflamación/patología , Inflamación/metabolismo , Inflamación/genética , Quimiocina CCL2/metabolismo , Masculino , Ratones Endogámicos C57BL , Microglía/metabolismo , Microglía/patología , Neuronas/metabolismo , Neuronas/patologíaRESUMEN
Zika virus (ZIKV), transmitted by Aedes mosquitoes, has been a global health concern since 2007. It primarily causes fetal microcephaly and neuronal defects through maternal transmission and induces neurological complications in adults. Recent studies report elevated proinflammatory cytokines and persistent neurological alterations post recovery, but the in vivo mechanisms remain unclear. In our study, viral RNA loads in the brains of mice infected with ZIKV peaked at 7 days post infection and returned to baseline by day 21, indicating recovery. RNA sequencing of the cerebral cortex at 7 and 21 days revealed upregulated genes related to neuroinflammation and microglial activation. Histological analyses indicated neuronal cell death and altered neurite morphology owing to severe neuroinflammation. Additionally, sustained microglial activation was associated with increased phospho-Tau levels, constituting a marker of neurodegeneration. These findings highlight how persistent microglial activation leads to neuronal dysfunction post ZIKV recovery, providing insights into the molecular pathogenesis of ZIKV-induced brain abnormalities.
Asunto(s)
Microglía , Neuronas , Infección por el Virus Zika , Virus Zika , Animales , Infección por el Virus Zika/virología , Infección por el Virus Zika/patología , Infección por el Virus Zika/metabolismo , Microglía/virología , Microglía/metabolismo , Microglía/patología , Ratones , Virus Zika/fisiología , Virus Zika/patogenicidad , Neuronas/virología , Neuronas/metabolismo , Neuronas/patología , Sinapsis/patología , Sinapsis/metabolismo , Encéfalo/virología , Encéfalo/patología , Encéfalo/metabolismo , Modelos Animales de Enfermedad , Femenino , Enfermedades Neuroinflamatorias/patología , Enfermedades Neuroinflamatorias/virología , Enfermedades Neuroinflamatorias/etiología , Enfermedades Neuroinflamatorias/metabolismo , Carga ViralRESUMEN
Even though several highly effective treatments have been developed for multiple sclerosis (MS), the underlying pathological mechanisms and drivers of the disease have not been fully elucidated. In recent years, there has been a growing interest in studying neuroinflammation in the context of glial cell involvement as there is increasing evidence of their central role in disease progression. Although glial cell communication and proper function underlies brain homeostasis and maintenance, their multiple effects in an MS brain remain complex and controversial. In this review, we aim to provide an overview of the contribution of glial cells, oligodendrocytes, astrocytes, and microglia in the pathology of MS during both the activation and orchestration of inflammatory mechanisms, as well as of their synergistic effects during the repair and restoration of function. Additionally, we discuss how the understanding of glial cell involvement in MS may provide new therapeutic targets either to limit disease progression or to facilitate repair.
Asunto(s)
Esclerosis Múltiple , Neuroglía , Enfermedades Neuroinflamatorias , Humanos , Esclerosis Múltiple/metabolismo , Esclerosis Múltiple/patología , Neuroglía/metabolismo , Neuroglía/patología , Animales , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neuroinflamatorias/patología , Microglía/metabolismo , Microglía/patología , Astrocitos/metabolismo , Astrocitos/patología , Oligodendroglía/metabolismo , Oligodendroglía/patología , Encéfalo/metabolismo , Encéfalo/patologíaRESUMEN
Understanding the sequence of cellular responses and their contributions to pathomorphogical changes in spinal white matter injuries is a prerequisite for developing efficient therapeutic strategies for spinal cord injury (SCI) as well as neurodegenerative and inflammatory diseases of the spinal cord such as amyotrophic lateral sclerosis and multiple sclerosis. We have developed several types of surgical procedures suitable for acute one-time and chronic recurrent in vivo multiphoton microscopy of spinal white matter [1]. Sophisticated surgical procedures were combined with transgenic mouse technology to image spinal tissue labeled with up to four fluorescent proteins (FPs) in axons, astrocytes, microglia, and blood vessels. To clearly separate the simultaneously excited FPs, spectral unmixing including iterative procedures was performed after imaging the diversely labeled spinal white matter with a custom-made 4-channel two-photon laser-scanning microscope. In our longitudinal multicellular studies of injured spinal white matter, we imaged axonal dynamics and invasion of microglia and astrocytes for a time course of over 200 days after SCI. Our methods offer ideal platforms for investigating acute and chronic cellular dynamics, cell-cell interactions, and metabolite fluctuations in health and disease as well as pharmacological manipulations in vivo.
Asunto(s)
Axones , Ratones Transgénicos , Traumatismos de la Médula Espinal , Sustancia Blanca , Animales , Sustancia Blanca/patología , Sustancia Blanca/metabolismo , Sustancia Blanca/diagnóstico por imagen , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/diagnóstico por imagen , Axones/patología , Axones/metabolismo , Neuroglía/metabolismo , Neuroglía/patología , Ratones , Microscopía de Fluorescencia por Excitación Multifotónica/métodos , Médula Espinal/patología , Médula Espinal/metabolismo , Microglía/metabolismo , Microglía/patología , Astrocitos/metabolismo , Astrocitos/patologíaRESUMEN
BACKGROUND: Depression is a chronic psychiatric disease of multifactorial etiology, and its pathophysiology is not fully understood. Stress and other chronic inflammatory pathologies are shared risk factors for psychiatric diseases, and comorbidities are features of major depression. Epidemiological evidence suggests that periodontitis, as a source of low-grade chronic systemic inflammation, may be associated with depression, but the underlying mechanisms are not well understood. METHODS: Periodontitis (P) was induced in Wistar: Han rats through oral gavage with the pathogenic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum for 12 weeks, followed by 3 weeks of chronic mild stress (CMS) to induce depressive-like behavior. The following four groups were established (n = 12 rats/group): periodontitis and CMS (P + CMS+), periodontitis without CMS, CMS without periodontitis, and control. The morphology and inflammatory phenotype of microglia in the frontal cortex (FC) were studied using immunofluorescence and bioinformatics tools. The endocannabinoid (EC) signaling and proteins related to synaptic plasticity were analyzed in FC samples using biochemical and immunohistochemical techniques. RESULTS: Ultrastructural and fractal analyses of FC revealed a significant increase in the complexity and heterogeneity of Iba1 + parenchymal microglia in the combined experimental model (P + CMS+) and increased expression of the proinflammatory marker inducible nitric oxide synthase (iNOS), while there were no changes in the expression of cannabinoid receptor 2 (CB2). In the FC protein extracts of the P + CMS + animals, there was a decrease in the levels of the EC metabolic enzymes N-acyl phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), diacylglycerol lipase (DAGL), and monoacylglycerol lipase (MAGL) compared to those in the controls, which extended to protein expression in neurons and in FC extracts of cannabinoid receptor 1 (CB1) and to the intracellular signaling molecules phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) and extracellular signal-regulated kinase 1/2 (ERK1/2). The protein levels of brain-derived neurotrophic factor (BDNF) and synaptophysin were also lower in P + CMS + animals than in controls. CONCLUSIONS: The combined effects on microglial morphology and inflammatory phenotype, the EC signaling, and proteins related to synaptic plasticity in P + CMS + animals may represent relevant mechanisms explaining the association between periodontitis and depression. These findings highlight potential therapeutic targets that warrant further investigation.
Asunto(s)
Depresión , Endocannabinoides , Microglía , Periodontitis , Ratas Wistar , Transducción de Señal , Animales , Ratas , Endocannabinoides/metabolismo , Microglía/metabolismo , Microglía/patología , Periodontitis/patología , Periodontitis/metabolismo , Transducción de Señal/fisiología , Depresión/metabolismo , Depresión/patología , Masculino , Modelos Animales de Enfermedad , Fenotipo , Inflamación/metabolismo , Inflamación/patologíaRESUMEN
We previously demonstrated that felodipine, an L-type calcium channel blocker, inhibits LPS-mediated neuroinflammatory responses in BV2 microglial cells and wild-type mice. However, the effects of felodipine on tau pathology, a hallmark of Alzheimer's disease (AD), have not been explored yet. Therefore, in the present study, we determined whether felodipine affects neuroinflammation and tau hyperphosphorylation in 3-month-old P301S transgenic mice (PS19), an early phase AD mice model for tauopathy. Felodipine administration decreased tauopathy-mediated microglial activation and NLRP3 expression in PS19 mice but had no effect on tauopathy-associated astrogliosis. In addition, felodipine treatment significantly reduced tau hyperphosphorylation at S202/Thr205 and Thr212/Ser214 residues via inhibiting JNK/P38 signaling in PS19 mice. Collectively, our results suggest that felodipine significantly ameliorates tau hyper-phosphorylation and tauopathy-associated neuroinflammatory responses in AD mice model for tauopathy and could be a novel therapeutic agent for AD.
Asunto(s)
Enfermedad de Alzheimer , Felodipino , Ratones Transgénicos , Microglía , Enfermedades Neuroinflamatorias , Proteínas Quinasas p38 Activadas por Mitógenos , Proteínas tau , Animales , Proteínas tau/metabolismo , Fosforilación/efectos de los fármacos , Enfermedades Neuroinflamatorias/tratamiento farmacológico , Enfermedades Neuroinflamatorias/metabolismo , Felodipino/farmacología , Felodipino/uso terapéutico , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Ratones , Modelos Animales de Enfermedad , Ratones Endogámicos C57BLRESUMEN
Ischemic stroke (IS) is a severe cerebrovascular disease with high disability and mortality rates, where the inflammatory response is crucial to its progression and prognosis. Efferocytosis, the prompt removal of dead cells, can reduce excessive inflammation after IS injury. While electroacupuncture (EA) has been shown to decrease inflammation post-ischemia/reperfusion (I/R), its link to efferocytosis is unclear. Our research identified ATP-binding cassette transporter A1 (Abca1) as a key regulator of the engulfment process of efferocytosis after IS by analyzing public datasets and validating findings in a mouse model, revealing its close ties to IS progression. We demonstrated that EA can reduce neuronal cell death and excessive inflammation caused by I/R. Furthermore, EA treatment increased Abca1 expression, prevented microglia activation, promoted M2 microglia polarization, and enhanced their ability to phagocytose injured neurons in I/R mice. This suggests that EA's modulation of efferocytosis could be a potential mechanism for reducing cerebral I/R injury, making regulators of efferocytosis steps a promising therapeutic target for EA benefits.
Asunto(s)
Transportador 1 de Casete de Unión a ATP , Electroacupuntura , Inflamación , Ratones Endogámicos C57BL , Microglía , Fagocitosis , Daño por Reperfusión , Animales , Microglía/metabolismo , Microglía/patología , Electroacupuntura/métodos , Transportador 1 de Casete de Unión a ATP/metabolismo , Daño por Reperfusión/patología , Daño por Reperfusión/terapia , Daño por Reperfusión/metabolismo , Inflamación/patología , Masculino , Isquemia Encefálica/patología , Isquemia Encefálica/metabolismo , Isquemia Encefálica/terapia , Ratones , Neuronas/metabolismo , Neuronas/patología , Modelos Animales de Enfermedad , EferocitosisRESUMEN
Glaucoma is a degenerative disease characterized by retinal ganglion cell (RGC) death and visual impairment caused by elevated intraocular pressure (IOP). Elevated IOP can activate microglia, which participate in ganglion cell injury. Based on the study of caveolin-1 (Cav-1) in glaucoma, we aimed to explore the effect and mechanism of Cav-1 on RGC apoptosis in mice with acute ocular hypertension (AOH). AOH mice were established, and Cav-1 was intravitreally injected. Retinal microglia and RGCs were isolated from neonatal mice. TUNEL staining, hematoxylin-eosin staining, immunohistochemistry, flow cytometry, PCR and western blotting were used to observe the effect of Cav-1 on RGCs and mouse retinas. The thickness of the whole retina and the inner retinal sublayer decreased significantly, retinal cell apoptosis increased after AOH injury, and Cav-1 treatment reversed the effect of AOH injury. In addition, Cav-1 treatment promoted the conversion of proinflammatory M1 microglia to anti-inflammatory M2 microglia. Microglia and RGCs were isolated from neonatal mice. Cav-1 protects RGCs from OGD/R-induced injury by changing the polarization status of retinal microglia in vitro. Further studies revealed that Cav-1 activated the Akt/PTEN signaling pathway and inhibited TLR4. Our study provides evidence that Cav-1 may be a promising therapeutic target for glaucoma.
Asunto(s)
Caveolina 1 , Glaucoma , Fosfohidrolasa PTEN , Proteínas Proto-Oncogénicas c-akt , Células Ganglionares de la Retina , Transducción de Señal , Receptor Toll-Like 4 , Animales , Células Ganglionares de la Retina/patología , Células Ganglionares de la Retina/metabolismo , Células Ganglionares de la Retina/efectos de los fármacos , Caveolina 1/metabolismo , Transducción de Señal/fisiología , Fosfohidrolasa PTEN/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratones , Glaucoma/metabolismo , Glaucoma/patología , Receptor Toll-Like 4/metabolismo , Ratones Endogámicos C57BL , Apoptosis/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Modelos Animales de EnfermedadRESUMEN
CSF1R-related disorder (CSF1R-RD) is a neurodegenerative condition that predominantly affects white matter due to genetic alterations in the CSF1R gene, which is expressed by microglia. We studied an elderly man with a hereditary, progressive dementing disorder of unclear etiology. Standard genetic testing for leukodystrophy and other neurodegenerative conditions was negative. Brain autopsy revealed classic features of adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), including confluent white matter degeneration with axonal spheroids and pigmented glial cells in the affected white matter, consistent with CSF1R-RD. Subsequent long-read sequencing identified a novel deletion in CSF1R that was not detectable with short-read exome sequencing. To gain insight into potential mechanisms underlying white matter degeneration in CSF1R-RD, we studied multiple brain regions exhibiting varying degrees of white matter pathology. We found decreased CSF1R transcript and protein across brain regions, including intact white matter. Single nuclear RNA sequencing (snRNAseq) identified two disease-associated microglial cell states: lipid-laden microglia (expressing GPNMB, ATG7, LGALS1, LGALS3) and inflammatory microglia (expressing IL2RA, ATP2C1, FCGBP, VSIR, SESN3), along with a small population of CD44+ peripheral monocyte-derived macrophages exhibiting migratory and phagocytic signatures. GPNMB+ lipid-laden microglia with ameboid morphology represented the end-stage disease microglia state. Disease-associated oligodendrocytes exhibited cell stress signatures and dysregulated apoptosis-related genes. Disease-associated oligodendrocyte precursor cells (OPCs) displayed a failure in their differentiation into mature myelin-forming oligodendrocytes, as evidenced by upregulated LRP1, PDGFRA, SOX5, NFIA, and downregulated NKX2-2, NKX6.2, SOX4, SOX8, TCF7L2, YY1, ZNF488. Overall, our findings highlight microglia-oligodendroglia crosstalk in demyelination, with CSF1R dysfunction promoting phagocytic and inflammatory microglia states, an arrest in OPC differentiation, and oligodendrocyte depletion.
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Neuroglía , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos , Humanos , Masculino , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Neuroglía/patología , Neuroglía/metabolismo , Leucoencefalopatías/genética , Leucoencefalopatías/patología , Leucoencefalopatías/metabolismo , Anciano , Microglía/patología , Microglía/metabolismo , Perfilación de la Expresión Génica , Transcriptoma , Sustancia Blanca/patología , Sustancia Blanca/metabolismo , Encéfalo/patología , Encéfalo/metabolismo , Receptor de Factor Estimulante de Colonias de MacrófagosRESUMEN
BACKGROUND: Leukocyte immunoglobulin-like receptor B4 (LILRB4) plays a significant role in regulating immune responses. LILRB4 in microglia might influence the infiltration of peripheral T cells. However, whether and how LILRB4 expression aggravates brain damage after acute ischemic stroke remains unclear. This study investigates the role of LILRB4 in modulating the immune response and its potential protective effects against ischemic brain injury in mice. METHODS AND RESULTS: Microglia-specific LILRB4 conditional knockout (LILRB4-KO) and overexpression transgenic (LILRB4-TG) mice were constructed by a Cre-loxP system. Then, they were used to investigate the role of LILRB4 after ischemic stroke using a transient middle cerebral artery occlusion (tMCAO) mouse model. Spatial transcriptomics analysis revealed increased LILRB4 expression in the ischemic hemisphere. Single-cell RNA sequencing (scRNA-seq) identified microglia-cluster3, an ischemia-associated microglia subcluster with elevated LILRB4 expression in the ischemic brain. Flow cytometry and immunofluorescence staining showed increased CD8+ T cell infiltration into the brain in LILRB4-KO-tMCAO mice. Behavioral tests, cortical perfusion maps, and infarct size measurements indicated that LILRB4-KO-tMCAO mice had more severe functional deficits and larger infarct sizes compared to Control-tMCAO and LILRB4-TG-tMCAO mice. T cell migration assays demonstrated that LILRB4-KD microglia promoted CD8+ T cell recruitment and activation in vitro, which was mitigated by CCL2 inhibition and recombinant arginase-1 addition. The scRNA-seq and spatial transcriptomics identified CCL2 was predominantly secreted from activated microglia/macrophage and increased CCL2 expression in LILRB4-KD microglia, suggesting a chemokine-mediated mechanism of LILRB4. CONCLUSION: LILRB4 in microglia plays a crucial role in modulating the post-stroke immune response by regulating CD8+ T cell infiltration and activation. Knockout of LILRB4 exacerbates ischemic brain injury by promoting CD8+ T cell recruitment. Overexpression of LILRB4, conversely, offers neuroprotection. These findings highlight the therapeutic potential of targeting LILRB4 and its downstream pathways to mitigate immune-mediated damage in ischemic stroke.
Asunto(s)
Linfocitos T CD8-positivos , Accidente Cerebrovascular Isquémico , Microglía , Receptores Inmunológicos , Regulación hacia Arriba , Animales , Ratones , Microglía/metabolismo , Microglía/patología , Linfocitos T CD8-positivos/metabolismo , Receptores Inmunológicos/genética , Receptores Inmunológicos/metabolismo , Accidente Cerebrovascular Isquémico/metabolismo , Accidente Cerebrovascular Isquémico/patología , Accidente Cerebrovascular Isquémico/inmunología , Accidente Cerebrovascular Isquémico/genética , Ratones Noqueados , Ratones Transgénicos , Ratones Endogámicos C57BL , Infarto de la Arteria Cerebral Media/patología , Infarto de la Arteria Cerebral Media/metabolismo , Lesiones Encefálicas/patología , Lesiones Encefálicas/metabolismo , MasculinoRESUMEN
AIMS: Microglial cells are integral to the pathogenesis of Alzheimer's disease (AD). The observed sex disparity in AD prevalence, with a notable predominance in women, implies a potential influence of sex hormones, such as androgens, on disease mechanisms. Despite this, the specific effects of androgens on microglia remain unclear. This study is designed to delineate the interplay between androgens and the survival and inflammatory profile of microglial cells, as well as to explore their contribution to the progression of AD. METHODS AND KEY FINDINGS: To create a chronic androgen deficiency model, 3-month-old wild-type (WT) mice and APP/PS1 mice underwent bilateral orchiectomy (ORX), with age-matched sham-operated controls. Cognitive and memory were evaluated at 5 and 12 months, paralleled by assessments of amyloid-beta (Aß) and microglial morphology in hippocampal and cortical areas. The ORX treatment in mice resulted in diminished microglial populations and morphological alterations, alongside an increase in Aß plaques and a concomitant decline in cognitive performance that exacerbated over time. In vitro, dihydrotestosterone (DHT) was found to stimulate microglial proliferation and ameliorate Aß1-42-induced apoptosis. SIGNIFICANCE: These findings suggested that androgens may exert a protective role, maintaining the normal proliferation and functionality of microglial cells. This preservation could potentially slow the progression of AD. As a result, our study provided a conceptual framework for the development of novel therapeutic strategies for AD.
Asunto(s)
Enfermedad de Alzheimer , Andrógenos , Ratones Transgénicos , Microglía , Animales , Microglía/patología , Microglía/metabolismo , Microglía/efectos de los fármacos , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/metabolismo , Masculino , Ratones , Andrógenos/farmacología , Andrógenos/metabolismo , Andrógenos/deficiencia , Orquiectomía , Péptidos beta-Amiloides/metabolismo , Ratones Endogámicos C57BL , Dihidrotestosterona/farmacología , Modelos Animales de Enfermedad , Hipocampo/patología , Hipocampo/metabolismo , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Factores de Edad , Placa Amiloide/patología , Placa Amiloide/metabolismoRESUMEN
Reactive changes of glial cells during neuroinflammation impact brain disorders and disease progression. Elucidating the mechanisms that control reactive gliosis may help us to understand brain pathophysiology and improve outcomes. Here, we report that adult ablation of autism spectrum disorder (ASD)-associated CHD8 in astrocytes attenuates reactive gliosis via remodeling chromatin accessibility, changing gene expression. Conditional Chd8 deletion in astrocytes, but not microglia, suppresses reactive gliosis by impeding astrocyte proliferation and morphological elaboration. Astrocyte Chd8 ablation alleviates lipopolysaccharide-induced neuroinflammation and septic-associated hypothermia in mice. Astrocytic CHD8 plays an important role in neuroinflammation by altering the chromatin landscape, regulating metabolic and lipid-associated pathways, and astrocyte-microglia crosstalk. Moreover, we show that reactive gliosis can be directly mitigated in vivo using an adeno-associated virus (AAV)-mediated Chd8 gene editing strategy. These findings uncover a role of ASD-associated CHD8 in the adult brain, which may warrant future exploration of targeting chromatin remodelers in reactive gliosis and neuroinflammation in injury and neurological diseases.
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Astrocitos , Gliosis , Animales , Gliosis/patología , Gliosis/metabolismo , Astrocitos/metabolismo , Astrocitos/patología , Ratones , Cromatina/metabolismo , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/patología , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neuroinflamatorias/patología , Ensamble y Desensamble de Cromatina , Microglía/metabolismo , Microglía/patología , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Ratones Endogámicos C57BL , Lipopolisacáridos/farmacología , Humanos , Ratones Noqueados , Masculino , Proliferación CelularRESUMEN
BACKGROUND: Epilepsy is a prevalent disorder of the central nervous system. Approximately, one-third of patients show resistance to pharmacological interventions. The pathogenesis of epilepsy is complex, and neuronal apoptosis plays a critical role. Aberrantly reactive astrocytes, induced by cytokine release from activated microglia, may lead to neuronal apoptosis. This study investigated the role of glucagon-like peptide 1 receptor (GLP1R) in microglial activation in epilepsy and its impact on astrocyte-mediated neurotoxicity. METHODS: We used human hippocampal tissue from patients with temporal lobe epilepsy and a pilocarpine-induced epileptic mouse model to assess neurobiological changes in epilepsy. BV2 microglial cells and primary astrocytes were used to evaluate cytokine release and astrocyte activation in vitro. The involvement of GLP1R was explored using the GLP1R agonist, Exendin-4 (Ex-4). RESULTS: Our findings indicated that reduced GLP1R expression in hippocampal microglia in both epileptic mouse models and human patients, correlated with increased cytokine release and astrocyte activation. Ex-4 treatment restored microglial homeostasis, decreased cytokine secretion, and reduced astrocyte activation, particularly of the A1 phenotype. These changes were associated with a reduction in neuronal apoptosis. In addition, Ex-4 treatment significantly decreased the frequency and duration of seizures in epileptic mice. CONCLUSIONS: This study highlights the crucial role of microglial GLP1R in epilepsy pathophysiology. GLP1R downregulation contributes to microglial- and astrocyte-mediated neurotoxicity, exacerbating neuronal death and seizures. Activation of GLP1R with Ex-4 has emerged as a promising therapeutic strategy to reduce neuroinflammation, protect neuronal cells, and control seizures in epilepsy. This study provides a foundation for developing novel antiepileptic therapies targeting microglial GLP1R, with the potential to improve outcomes in patients with epilepsy.
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Apoptosis , Receptor del Péptido 1 Similar al Glucagón , Hipocampo , Microglía , Neuronas , Animales , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Apoptosis/efectos de los fármacos , Receptor del Péptido 1 Similar al Glucagón/agonistas , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Humanos , Masculino , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/patología , Ratones , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Hipocampo/patología , Exenatida/farmacología , Exenatida/uso terapéutico , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Astrocitos/patología , Epilepsia/tratamiento farmacológico , Epilepsia/metabolismo , Epilepsia/inducido químicamente , Enfermedades Neuroinflamatorias/tratamiento farmacológico , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neuroinflamatorias/patología , Femenino , Adulto , Pilocarpina , Modelos Animales de Enfermedad , Citocinas/metabolismo , Ratones Endogámicos C57BL , Epilepsia del Lóbulo Temporal/tratamiento farmacológico , Epilepsia del Lóbulo Temporal/metabolismo , Epilepsia del Lóbulo Temporal/patología , Persona de Mediana EdadRESUMEN
AIMS: Cognitive dysfunction and systemic disease activity are common manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE), a condition that affects a patient's health and quality of life. Clinical and preclinical studies have demonstrated that intermittent fasting (IF) improves health conditions and quality of life. Therefore, we aimed to test whether IF improves cognitive dysfunction and systemic disease activities in mice with NPSLE and to examine the underlying mechanisms. MAIN METHODS: NPSLE-prone MRL/lpr mice underwent 8 weeks of alternate-day fasting or ad libitum feeding, followed by behavioral tests to assess cognitive manifestations and biochemical tests to evaluate systemic disease activities. KEY FINDINGS: IF significantly improved cognitive functionality, decreased blood-brain barrier permeability, and reduced the activation of astrocytes and microglia in the hippocampi of MRL/lpr mice. IF also improved systemic disease activities, including reduced kidney glomerular injury and interstitial inflammation, peripheral blood autoantibody titer, and splenic T lymphocyte contents. Mechanistic studies demonstrated that IF attenuates cognitive dysfunction by facilitating the microglial transition to the M2-like phenotype via the AMPK/PPARγ/NF-κB pathway. SIGNIFICANCE: Together, observations from this study suggest a potential therapeutic benefit of IF in the treatment of cognitive dysfunction in patients with NPSLE.
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Disfunción Cognitiva , Ayuno , Vasculitis por Lupus del Sistema Nervioso Central , Ratones Endogámicos MRL lpr , Animales , Ratones , Disfunción Cognitiva/etiología , Femenino , Barrera Hematoencefálica/metabolismo , Modelos Animales de Enfermedad , Microglía/patología , Microglía/metabolismo , Lupus Eritematoso Sistémico/complicaciones , Ayuno IntermitenteRESUMEN
BACKGROUND: In addition to primary injury, secondary injuries related to BBB disruption and immune-inflammatory response also play an important role in intracerebral hemorrhage (ICH). And the Golgi apparatus play an important role in the state of ICH. METHODS: ICH model and GM130-silencing ICH model were established in SD rats. The Garcia score was used to score the neurological defects of the rats. Blood-brain barrier (BBB) integrity were assessed by amount of extravasated Evans blue, and tight junction proteins. The expression of PD-L1 and GM130were detected through Western-blot and the subtype of microglia was showing with Immunofluorescence staining. RESULTS: Compared with the ICH group, GM130-silencing ICH rats got a worsened neurological deficit and enlarged volume of the hematoma. Evan's blue extravasation aggravated as well. The expression of GM130 in peri-hematoma tissue was further decreased, and the morphology and structure of the Golgi apparatus were further damaged. Meanwhile, the GM130 deficit resulted in decreased expression of PD-L1 and more polarization of microglia to the M1 subtype. CONCLUSION: We demonstrate that GM130 could influence the integrity of BBB and plays a role in neuroinflammation via regulation of PD-L1 after ICH. The manipulation of GM130 might be a promising therapeutical target in ICH.
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Antígeno B7-H1 , Barrera Hematoencefálica , Hemorragia Cerebral , Proteínas de la Membrana , Microglía , Animales , Masculino , Ratas , Autoantígenos , Antígeno B7-H1/metabolismo , Antígeno B7-H1/genética , Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/patología , Hemorragia Cerebral/metabolismo , Hemorragia Cerebral/genética , Hemorragia Cerebral/patología , Modelos Animales de Enfermedad , Regulación hacia Abajo , Aparato de Golgi/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Microglía/metabolismo , Microglía/patología , Ratas Sprague-DawleyRESUMEN
Parkinson's disease (PD) is a neurodegenerative disorder with a complex and multifactorial pathogenesis. This chapter delves into the critical role of astrocytes in PD. Once viewed as supporting cells in the central nervous system, astrocytes have emerged as key players in both maintaining neuronal health and contributing to neurodegeneration in PD. Their functions play a dual role in the progression of PD, ranging from protective functions like secretion of neurotrophic factors and clearance of α-synuclein to detrimental functions like promotion of neuroinflammation. This chapter is structured into three primary sections: the morphological and functional organization of astrocytes, astrocytic calcium signaling, and the role of astrocyte heterogeneity in PD. We provide a detailed exploration of astrocytic organelles, bidirectional astrocyte-neuron interactions, and the impact of astrocytic secretions such as antioxidant molecules and neurotrophic factors. Furthermore, we discuss the influence of astrocytes on non-neuronal cells, including interactions with microglia and the blood-brain barrier (BBB). By examining the multifaceted roles of astrocytes, in this chapter, we aim to bridge basic astrocyte biology with the clinical complexities of PD, offering insights into novel therapeutic strategies. The inclusion of astrocyte biology in our broader research approach will aid in the development of more effective treatment strategies for PD.
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Astrocitos , Enfermedad de Parkinson , Astrocitos/metabolismo , Astrocitos/patología , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/patología , Humanos , Barrera Hematoencefálica/metabolismo , Microglía/metabolismo , Microglía/patología , Animales , Factores de Crecimiento Nervioso/metabolismo , alfa-Sinucleína/metabolismo , Señalización del Calcio/fisiología , Neuronas/metabolismo , Neuronas/patologíaRESUMEN
Human microglia (HMC) are stress-induced inflammatory cells of the retina. It is unknown whether severe hypoglycaemia causes inflammation in microglia, affects the permeability of human retinal microvascular endothelial cells (HRMECs), and causes retinal damage. This study aimed to explore the effects of severe hypoglycaemia on retinal microglial inflammation and endothelial cell permeability and evaluate the damage caused by hypoglycaemia to the retina. The CCK-8 assay was used to measure cell viability. Western blotting was used to detect IL-1ß, IL-6, TNF- α, claudin-1, and occludin expression. ELISA was used to detect IL-1ß, IL-6, and TNF- α. Transmission electron microscopy (TEM) and haematoxylin and eosin staining were used to observe the retinal structure. Immunohistochemistry and immunofluorescence staining assays were also used to detect IL-1ß, IL-6, TNF- α, claudin-1, and occludin expression. Severe hypoglycaemia promoted inflammation in HMC3 cells. Inflammation caused by hypoglycaemia leads to the decreased expression of tight junction proteins. In vivo, severe hypoglycaemia induced structural damage to the retina, increased the expression of inflammatory factors, and decreased the expression of tight junction proteins. Our results suggest that severe hypoglycaemia leads to acute retinal inflammation, affecting the permeability of HRMECs and causing retinal damage.