RESUMEN
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. Syncytin-1 (Syn), an envelope glycoprotein encoded by the env gene of the human endogenous retrovirus-W family, has been resorted to be highly expressed in biopsies from the muscles from ALS patients; however, the specific regulatory role of Syn during ALS progression remains uncovered. In this study, C57BL/6 mice were injected with adeno-associated virus-overexpressing Syn, with or without Fasudil administration. The Syn expression was assessed by quantitative real-time polymerase chain reaction and immunohistochemistry analysis. The histological change of anterior tibial muscles was determined by hematoxylin-eosin staining. Qualitative ultrastructural analysis of electron micrographs obtained from lumbar spinal cords was carried out. Serum inflammatory cytokines were assessed by enzyme linked immunosorbent assay (ELISA) assay and motor function was recorded using Basso, Beattie, and Bresnahan (BBB) scoring, climbing test and treadmill running test. Immunofluorescence and western blot assays were conducted to examine microglial- and motor neurons-related proteins. Syn overexpression significantly caused systemic inflammatory response, muscle tissue lesions, and motor dysfunction in mice. Meanwhile, Syn overexpression promoted the impairment of motor neuron, evidenced by the damaged structure of the neurons and reduced expression of microtubule-associated protein 2, HB9, neuronal nuclei and neuron-specific enolase in Syn-induced mice. In addition, Syn overexpression greatly promoted the expression of CD16/CD32 and inducible nitric oxide synthase (M1 phenotype markers), and reduced the expression of CD206 and arginase 1 (M2 phenotype markers). Importantly, the above changes caused by Syn overexpression were partly abolished by Fasudil administration. This study provides evidence that Syn-activated microglia plays a pivotal role during the progression of ALS.
Asunto(s)
1-(5-Isoquinolinesulfonil)-2-Metilpiperazina , Ratones Endogámicos C57BL , Microglía , Neuronas Motoras , Animales , Microglía/efectos de los fármacos , Microglía/metabolismo , Neuronas Motoras/efectos de los fármacos , Neuronas Motoras/metabolismo , Ratones , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/análogos & derivados , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/farmacología , Productos del Gen env , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Esclerosis Amiotrófica Lateral/metabolismo , Proteínas Gestacionales/metabolismo , Masculino , Citocinas/metabolismo , Modelos Animales de Enfermedad , Actividad Motora/efectos de los fármacos , Médula Espinal/metabolismo , Médula Espinal/efectos de los fármacosRESUMEN
BACKGROUND AND OBJECTIVES: Spinal cord injury (SCI) results in significant neurological deficits, and microglia play the critical role in regulating the immune microenvironment and neurological recovery. Protein lactylation has been found to modulate the function of immune cells. Therefore, this study aimed to elucidate the effects of glycolysis-derived lactate on microglial function and its potential neuroprotective mechanisms via lactylation after SCI. METHODS: Single-cell RNA sequencing (scRNA-seq) data were obtained from figshare to analyze cellular and molecular alterations within the spinal cord post-SCI, further focusing on the expression of microglia-related genes for cell sub-clustering, trajectory analysis, and glycolysis function analysis. We also evaluated the expression of lactylation-related genes in microglia between day 7 after SCI and sham group. Additionally, we established the mice SCI model and performed the bulk RNA sequencing in a time-dependent manner. The expression of glycolysis- and lactylation-related genes was evaluated, as well as the immune infiltration analysis based on the lactylation-related genes. Then, we investigated the bio-effects of lactate on the inflammation and polarization phenotype of microglia. Finally, adult male C57BL/6 mice were subjected to exercise first to increase lactate level, before SCI surgery, aiming to evaluate the protective effects of lactate-mediated lactylation of microglia-related proteins on SCI. RESULTS: scRNA-seq identified a subcluster of microglia, recombinant chemokine C-X3-C-motif receptor 1+ (CX3CR1+) microglia, which is featured by M1-like phenotype and increased after SCI. KEGG analysis revealed the dysfunctional glycolysis in microglia after SCI surgery, and AUCell analysis suggested that the decreased glycolysis an increased oxidative phosphorylation in CX3CR1+ microglia. Differential gene analysis suggested that several lactylation-related genes (Fabp5, Lgals1, Vim, and Nefl) were downregulated in CX3CR1+ microglia at day 7 after SCI, further validated by the results from bulk RNA sequencing. Immunofluorescence staining indicated the expression of lactate dehydrogenase A (LDHA) in CX3CR1+ microglia also decreased at day 7 after SCI. Cellular experiments demonstrated that the administration of lactate could increase the lactylation level and inhibit the pro-inflammatory phenotype in microglia. Functionally, exercise-mediated lactate production resulted in improved locomotor recovery and decreased inflammatory markers in SCI mice compared to SCI alone. CONCLUSIONS: In the subacute phase of SCI, metabolic remodeling in microglia may be key therapeutic targets to promote nerve regeneration, and lactate contributed to neuroprotection after SCI by influencing microglial lactylation and inflammatory phenotype, which offered a novel approach for therapeutic intervention.
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Ácido Láctico , Ratones Endogámicos C57BL , Microglía , Análisis de Secuencia de ARN , Análisis de la Célula Individual , Traumatismos de la Médula Espinal , Animales , Traumatismos de la Médula Espinal/metabolismo , Microglía/efectos de los fármacos , Microglía/metabolismo , Ratones , Masculino , Ácido Láctico/metabolismo , Análisis de Secuencia de ARN/métodos , Fármacos Neuroprotectores/farmacología , Glucólisis/efectos de los fármacos , Glucólisis/fisiologíaRESUMEN
BACKGROUND: Alzheimer's disease (AD) features progressive neurodegeneration and microglial activation that results in dementia and cognitive decline. The release of soluble amyloid (Aß) oligomers into the extracellular space is an early feature of AD pathology. This can promote excitotoxicity and microglial activation. Microglia can adopt several activation states with various functional outcomes. Protective microglial activation states have been identified in response to Aß plaque pathology in vivo. However, the role of microglia and immune mediators in neurotoxicity induced by soluble Aß oligomers is unclear. Further, there remains a need to identify druggable molecular targets that promote protective microglial states to slow or prevent the progression of AD. METHODS: Hippocampal entorhinal brain slice culture (HEBSC) was employed to study mechanisms of Aß1-42 oligomer-induced neurotoxicity as well as the role of microglia. The roles of glutamate hyperexcitation and immune signaling in Aß-induced neurotoxicity were assessed using MK801 and neutralizing antibodies to the TNF-related apoptosis-inducing ligand (TRAIL) respectively. Microglial activation state was manipulated using Gi-hM4di designer receptor exclusively activated by designer drugs (DREADDs), microglial depletion with the colony-stimulating factor 1 receptor (CSF1R) antagonist PLX3397, and microglial repopulation (PLX3397 withdrawal). Proteomic changes were assessed by LC-MS/MS in microglia isolated from control, repopulated, or Aß-treated HEBSCs. RESULTS: Neurotoxicity induced by soluble Aß1-42 oligomers involves glutamatergic hyperexcitation caused by the proinflammatory mediator and death receptor ligand TRAIL. Microglia were found to have the ability to both promote and restrain Aß-induced toxicity. Induction of microglial Gi-signaling with hM4di to prevent pro-inflammatory activation blunted Aß neurotoxicity, while microglial depletion with CSF1R antagonism worsened neurotoxicity caused by Aß as well as TRAIL. HEBSCs with repopulated microglia, however, showed a near complete resistance to Aß-induced neurotoxicity. Comparison of microglial proteomes revealed that repopulated microglia have a baseline anti-inflammatory and trophic phenotype with a predicted pathway activation that is nearly opposite that of Aß-exposed microglia. mTORC2 and IRF7 were identified as potential targets for intervention. CONCLUSION: Microglia are key mediators of both protection and neurodegeneration in response to Aß. Polarizing microglia toward a protective state could be used as a preventative strategy against Aß-induced neurotoxicity.
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Péptidos beta-Amiloides , Microglía , Fragmentos de Péptidos , Ligando Inductor de Apoptosis Relacionado con TNF , Microglía/metabolismo , Microglía/efectos de los fármacos , Péptidos beta-Amiloides/toxicidad , Péptidos beta-Amiloides/metabolismo , Animales , Fragmentos de Péptidos/toxicidad , Fragmentos de Péptidos/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/toxicidad , Ratones , Hipocampo/metabolismo , Hipocampo/efectos de los fármacos , Ratones Endogámicos C57BL , Corteza Entorrinal/metabolismo , Corteza Entorrinal/efectos de los fármacos , Corteza Entorrinal/patología , Técnicas de Cultivo de ÓrganosRESUMEN
Mucopolysaccharidoses are inherited metabolic disorders caused by the deficiency in lysosomal enzymes required to break down glycosaminoglycans. Accumulation of glycosaminoglycans leads to progressive, systemic degenerative disease. The central nervous system is particularly affected, resulting in developmental delays, neurological regression, and early mortality. Current treatments fail to adequately address neurological defects. Here we explore the potential of human induced pluripotent stem cell (hiPSC)-derived microglia progenitors as a one-time, allogeneic off-the-shelf cell therapy for several mucopolysaccharidoses (MPS). We show that hiPSC-derived microglia progenitors, possessing normal levels of lysosomal enzymes, can deliver functional enzymes into four subtypes of MPS knockout cell lines through mannose-6-phosphate receptor-mediated endocytosis in vitro. Additionally, our findings indicate that a single administration of hiPSC-derived microglia progenitors can reduce toxic glycosaminoglycan accumulation and prevent behavioral deficits in two different animal models of MPS. Durable efficacy is observed for eight months after transplantation. These results suggest a potential avenue for treating MPS with hiPSC-derived microglia progenitors.
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Modelos Animales de Enfermedad , Glicosaminoglicanos , Células Madre Pluripotentes Inducidas , Microglía , Mucopolisacaridosis , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Animales , Microglía/metabolismo , Humanos , Mucopolisacaridosis/terapia , Ratones , Glicosaminoglicanos/metabolismo , Ratones Noqueados , Diferenciación Celular , Trasplante de Células Madre/métodos , Lisosomas/metabolismoRESUMEN
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.
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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
Acute ischemic stroke (AIS) is a major global health concern due to its high mortality and disability rates. Hemorrhagic transformation, a common complication of AIS, leads to poor prognosis yet lacks effective treatments. Preclinical studies indicate that hyperbaric oxygen (HBO) treatment within 12 h of AIS onset alleviates ischemia/reperfusion injuries, including hemorrhagic transformation. However, clinical trials have yielded conflicting results, suggesting some underlying mechanisms remain unclear. In this study, we confirmed that HBO treatments beginning within 1 h post reperfusion significantly alleviated the haemorrhage and neurological deficits in hyperglycemic transient middle cerebral arterial occlusion (tMCAO) mice, partly due to the inhibition of the NLRP3 inflammasome-mediated pro-inflammatory response in microglia. Notably, reactive oxygen species (ROS) mediate the anti-inflammatory and protective effect of early HBO treatment, as edaravone and N-Acetyl-L-Cysteine (NAC), two commonly used antioxidants, reversed the suppressive effect of HBO treatment on NLRP3 inflammasome-mediated inflammation in microglia. Furthermore, NAC countered the protective effect of early HBO treatment in tMCAO mice with hyperglycemia. These findings support that early HBO treatment is a promising intervention for AIS, however, caution is warranted when combining antioxidants with HBO treatment. Further assessments are needed to clarify the role of antioxidants in HBO therapy for AIS.
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Oxigenoterapia Hiperbárica , Hiperglucemia , Microglía , Especies Reactivas de Oxígeno , Animales , Microglía/metabolismo , Microglía/efectos de los fármacos , Oxigenoterapia Hiperbárica/métodos , Ratones , Especies Reactivas de Oxígeno/metabolismo , Hiperglucemia/metabolismo , Hiperglucemia/complicaciones , Masculino , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Inflamasomas/metabolismo , Modelos Animales de Enfermedad , Accidente Cerebrovascular/terapia , Accidente Cerebrovascular/metabolismo , Antioxidantes/farmacología , Ratones Endogámicos C57BL , Infarto de la Arteria Cerebral Media/terapia , Edaravona/farmacología , Daño por Reperfusión/metabolismoRESUMEN
Gulf War Illness (GWI) is a chronic multisymptom disorder that affects approximately 25-32% of Gulf War veterans and is characterized by a number of symptoms such as cognitive impairment, psychiatric disturbances, chronic fatigue and gastrointestinal distress, among others. While the exact etiology of GWI is unknown, it is believed to have been caused by toxic exposures encountered during deployment in combination with other factors such as stress. In the present study we sought to evaluate the hypothesis that exposure to the toxin permethrin could prime neuroinflammatory stress response and elicit psychiatric symptoms associated with GWI. Specifically, we developed a mouse model of GWI, to evaluate the effects of chronic permethrin exposure followed by unpredictable stress. We found that subjecting mice to 14 days of chronic permethrin exposure followed by 7 days of unpredictable stress resulted in the development of depression-like behavior. This behavioral change coincided with distinct alterations in the microglia phenotype, indicating microglial activation in the hippocampus. We revealed that blocking microglial activation through Gi inhibitory DREADD receptors in microglia effectively prevented the behavioral change associated with permethrin and stress exposure. To elucidate the transcriptional networks impacted within distinct microglia populations linked to depression-like behavior in mice exposed to both permethrin and stress, we conducted a single-cell RNA sequencing analysis using 21,566 single nuclei collected from the hippocampus of mice. For bioinformatics, UniCell Deconvolve was a pre-trained, interpretable, deep learning model used to deconvolve cell type fractions and predict cell identity across spatial datasets. Our bioinformatics analysis identified significant alterations in permethrin exposure followed by stress-associated microglia population, notably pathways related to neuronal development, neuronal communication, and neuronal morphogenesis, all of which are associated with neural synaptic plasticity. Additionally, we observed permethrin exposure followed by stress-mediated changes in signal transduction, including modulation of chemical synaptic transmission, regulation of neurotransmitter receptors, and regulation of postsynaptic neurotransmitter receptor activity, a known contributor to the pathophysiology of depression in a subset of the hippocampal pyramidal neurons in CA3 subregions. Our findings tentatively suggest that permethrin may prime microglia towards a state of inflammatory activation that can be triggered by psychological stressors, resulting in depression-like behavior and alterations of neural plasticity. These findings underscore the significance of synergistic interactions between multi-causal factors associated with GWI.
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Depresión , Modelos Animales de Enfermedad , Microglía , Enfermedades Neuroinflamatorias , Permetrina , Síndrome del Golfo Pérsico , Animales , Permetrina/toxicidad , Ratones , Síndrome del Golfo Pérsico/inducido químicamente , Síndrome del Golfo Pérsico/patología , Microglía/efectos de los fármacos , Microglía/metabolismo , Depresión/inducido químicamente , Depresión/etiología , Enfermedades Neuroinflamatorias/inducido químicamente , Enfermedades Neuroinflamatorias/metabolismo , Masculino , Ratones Endogámicos C57BL , Estrés PsicológicoRESUMEN
Tumor-associated macrophages/microglia (TAMs) are highly plastic and heterogeneous immune cells that can be immune-supportive or tumor-supportive depending of the microenvironment. TAMs are the most abundant immune cells in glioblastoma (GB), and play a key role in immunosuppression. Therefore, TAMs reprogramming toward immune-supportive cells is a promising strategy to overcome immunosuppression. By leveraging scRNAseq human GB databases, we identified that Inhibitor of Apoptosis Proteins (IAP) were expressed by TAMs. To investigate their role in TAMs-related immunosuppression, we antagonized IAP using the central nervous system permeant SMAC mimetic GDC-0152 (SMg). On explants and cultured immune cells isolated from human GB samples, SMg modified TAMs activity. We showed that SMg treatment promoted microglia pro-apoptotic and anti-tumoral function via caspase-3 pro-inflammatory cleavage and the inhibition of tumoroids growth. Then we designed a relevant immunogenic mouse GB model to decipher the spatio-temporal densities, distribution, phenotypes and function of TAMs with or without SMg treatment. We used 3D imaging techniques, a transgenic mouse with fluorescent TAM subsets and mass cytometry. We confirmed that SMg promoted microglia activation, antigen-presenting function and tumor infiltration. In addition, we observed a remodeling of blood vessels, a decrease in anti-inflammatory macrophages and an increased level of monocytes and their mo-DC progeny. This remodeling of the TAM landscape is associated with an increase in CD8 T cell density and activation. Altogether, these results demonstrated that SMg drives the immunosuppressive basal microglia toward an active phenotype with pro-apoptotic and anti-tumoral function and modifies the GB immune landscape. This identifies IAP as targets of choice for a potential mechanism-based therapeutic strategy and SMg as a promising molecule for this application.
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Glioblastoma , Microglía , Fenotipo , Microambiente Tumoral , Glioblastoma/inmunología , Glioblastoma/patología , Microambiente Tumoral/efectos de los fármacos , Microambiente Tumoral/inmunología , Animales , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/inmunología , Humanos , Ratones , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/patología , Proteínas Reguladoras de la Apoptosis/metabolismo , Ratones Endogámicos C57BL , Proteínas Mitocondriales/metabolismo , Línea Celular Tumoral , Macrófagos Asociados a Tumores/inmunología , Macrófagos Asociados a Tumores/metabolismo , Macrófagos Asociados a Tumores/efectos de los fármacos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ratones TransgénicosRESUMEN
BACKGROUND: Ischemic stroke (IS) is a severe neurological disorder with a pathogenesis that remains incompletely understood. Recently, a novel form of cell death known as disulfidptosis has garnered significant attention in the field of ischemic stroke research. This study aims to investigate the mechanistic roles of disulfidptosis-related genes (DRGs) in the context of IS and to examine their correlation with immunopathological features. METHODS: To enhance our understanding of the mechanistic underpinnings of disulfidptosis in IS, we initially retrieved the expression profile of peripheral blood from human IS patients from the GEO database. We then utilized a suite of machine learning algorithms, including LASSO, random forest, and SVM-RFE, to identify and validate pivotal genes. Furthermore, we developed a predictive nomogram model, integrating multifactorial logistic regression analysis and calibration curves, to evaluate the risk of IS. For the analysis of single-cell sequencing data, we employed a range of analytical tools, such as "Monocle" and "CellChat," to assess the status of immune cell infiltration and to characterize intercellular communication networks. Additionally, we utilized an oxygen-glucose deprivation (OGD) model to investigate the effects of SLC7A11 overexpression on microglial polarization. RESULTS: This study successfully identified key genes associated with disulfidptosis and developed a reliable nomogram model using machine learning algorithms to predict the risk of ischemic stroke. Examination of single-cell sequencing data showed a robust correlation between disulfidptosis levels and the infiltration of immune cells. Furthermore, "CellChat" analysis elucidated the intricate characteristics of intercellular communication networks. Notably, the TNF signaling pathway was found to be intimately linked with the disulfidptosis signature in ischemic stroke. In an intriguing finding, the OGD model demonstrated that SLC7A11 expression suppresses M1 polarization while promoting M2 polarization in microglia. CONCLUSION: The significance of our findings lies in their potential to shed light on the pathogenesis of ischemic stroke, particularly by underscoring the pivotal role of disulfidptosis-related genes (DRGs). These insights could pave the way for novel therapeutic strategies targeting DRGs to mitigate the impact of ischemic stroke.
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Accidente Cerebrovascular Isquémico , Aprendizaje Automático , Análisis de la Célula Individual , Accidente Cerebrovascular Isquémico/genética , Humanos , Microglía/metabolismo , Animales , Algoritmos , Ratones , Nomogramas , Muerte Celular/genética , Transcriptoma , MasculinoRESUMEN
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.
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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
BACKGROUND: Glioblastoma (GBM) is an immunosuppressive, universally lethal cancer driven by glioblastoma stem cells (GSCs). The interplay between GSCs and immunosuppressive microglia plays crucial roles in promoting the malignant growth of GBM; however, the molecular mechanisms underlying this crosstalk are unclear. This study aimed to investigate the role of POSTN in maintaining GSCs and the immunosuppressive phenotype of microglia. METHODS: The expression of POSTN in GBM was identified via immunohistochemistry, quantitative real-time PCR, and immunoblotting. Tumorsphere formation assay, Cell Counting Kit-8 assay and immunofluorescence were used to determine the key role of POSTN in GSC maintenance. ChIP-seq and ChIP-PCR were conducted to confirm the binding sequences of ß-catenin in the promoter region of FOSL1. Transwell migration assays, developmental and functional analyses of CD4+ T cells, CFSE staining and analysis, enzyme-linked immunosorbent assays and apoptosis detection tests were used to determine the key role of POSTN in maintaining the immunosuppressive phenotype of microglia and thereby promoting the immunosuppressive tumor microenvironment. Furthermore, the effects of POSTN on GSC maintenance and the immunosuppressive phenotype of microglia were investigated in a patient-derived xenograft model and orthotopic glioma mouse model, respectively. RESULTS: Our findings revealed that POSTN secreted from GSCs promotes GSC self-renewal and tumor growth via activation of the αVß3/PI3K/AKT/ß-catenin/FOSL1 pathway. In addition to its intrinsic effects on GSCs, POSTN can recruit microglia and upregulate CD70 expression in microglia through the αVß3/PI3K/AKT/NFκB pathway, which in turn promotes Treg development and functionality and supports the formation of an immunosuppressive tumor microenvironment. In both in vitro models and orthotopic mouse models of GBM, POSTN depletion disrupted GSC maintenance, decreased the recruitment of immunosuppressive microglia and suppressed GBM growth. CONCLUSION: Our findings reveal that POSTN plays critical roles in maintaining GSCs and the immunosuppressive phenotype of microglia and provide a new therapeutic target for treating GBM.
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Moléculas de Adhesión Celular , Glioblastoma , Microglía , Células Madre Neoplásicas , Glioblastoma/metabolismo , Glioblastoma/patología , Glioblastoma/inmunología , Glioblastoma/genética , Humanos , Animales , Ratones , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Células Madre Neoplásicas/inmunología , Microglía/metabolismo , Moléculas de Adhesión Celular/metabolismo , Moléculas de Adhesión Celular/genética , Fenotipo , Microambiente Tumoral , Línea Celular Tumoral , Proliferación Celular , Modelos Animales de Enfermedad , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/genética , Transducción de SeñalRESUMEN
Ischemic stroke is a common cause of mortality and severe disability in human and currently lacks effective treatment. Neuronal activation and neuroinflammation are the major two causes of neuronal damage. However, little is known about the connection of these two phenomena. This study uses middle cerebral artery occlusion mouse model and chemogenetic techniques to study the underlying mechanisms of neuronal excitotoxicity and severe neuroinflammation after ischemic stroke. Chemogenetic inhibition of neuronal activity in ipsilesional M1 alleviates infarct area and neuroinflammation, and improves motor recovery in ischemia mice. This study identifies that ischemic challenge triggers neuron to produce unique small extracellular vesicles (EVs) to aberrantly activate adjacent neurons which enlarge the neuron damage range. Importantly, these EVs also drive microglia activation to exacerbate neuroinflammation. Mechanistically, EVs from ischemia-evoked neuronal activity induce neuronal apoptosis and innate immune responses by transferring higher miR-100-5p to adjacent neuron and microglia. MiR-100-5p can bind to and activate TLR7 through U18U19G20-motif, thereby activating NF-κB pathway. Furthermore, knock-down of miR-100-5p expression improves poststroke outcomes in mice. Taken together, this study suggests that the combination of inhibiting aberrant neuronal activity and the secretion of specific EVs-miRNAs may serve as novel methods for stroke treatment.
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Vesículas Extracelulares , Ratones Endogámicos C57BL , MicroARNs , Microglía , Neuronas , Accidente Cerebrovascular , Animales , Vesículas Extracelulares/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Microglía/metabolismo , Neuronas/metabolismo , Ratones , Masculino , Receptor Toll-Like 7/metabolismo , Receptor Toll-Like 7/genética , Modelos Animales de Enfermedad , FN-kappa B/metabolismo , Enfermedades Neuroinflamatorias/metabolismo , Infarto de la Arteria Cerebral Media , Apoptosis , Inmunidad Innata , Humanos , Glicoproteínas de MembranaRESUMEN
Alzheimer's disease (AD) is the leading form of dementia, characterized by the accumulation and aggregation of amyloid in brain. Transient receptor potential vanilloid 2 (TRPV2) is an ion channel involved in diverse physiopathological processes, including microglial phagocytosis. Previous studies suggested that cannabidiol (CBD), an activator of TRPV2, improves microglial amyloid-ß (Aß) phagocytosis by TRPV2 modulation. However, the molecular mechanism of TRPV2 in microglial Aß phagocytosis remains unknown. In this study, we aimed to investigate the involvement of TRPV2 channel in microglial Aß phagocytosis and the underlying mechanisms. Utilizing human datasets, mouse primary neuron and microglia cultures, and AD model mice, to evaluate TRPV2 expression and microglial Aß phagocytosis in both in vivo and in vitro. TRPV2 was expressed in cortex, hippocampus, and microglia.Cannabidiol (CBD) could activate and sensitize TRPV2 channel. Short-term CBD (1 week) injection intraperitoneally (i.p.) reduced the expression of neuroinflammation and microglial phagocytic receptors, but long-term CBD (3 week) administration (i.p.) induced neuroinflammation and suppressed the expression of microglial phagocytic receptors in APP/PS1 mice. Furthermore, the hyper-sensitivity of TRPV2 channel was mediated by tyrosine phosphorylation at the molecular sites Tyr(338), Tyr(466), and Tyr(520) by protein tyrosine kinase JAK1, and these sites mutation reduced the microglial Aß phagocytosis partially dependence on its localization. While TRPV2 was palmitoylated at Cys 277 site and blocking TRPV2 palmitoylation improved microglial Aß phagocytosis. Moreover, it was demonstrated that TRPV2 palmitoylation was dynamically regulated by ZDHHC21. Overall, our findings elucidated the intricate interplay between TRPV2 channel regulated by tyrosine phosphorylation/dephosphorylation and cysteine palmitoylation/depalmitoylation, which had divergent effects on microglial Aß phagocytosis. These findings provide valuable insights into the underlying mechanisms linking microglial phagocytosis and TRPV2 sensitivity, and offer potential therapeutic strategies for managing AD.
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Péptidos beta-Amiloides , Lipoilación , Ratones Transgénicos , Microglía , Fagocitosis , Canales Catiónicos TRPV , Tirosina , Animales , Ratones , Microglía/metabolismo , Microglía/efectos de los fármacos , Canales Catiónicos TRPV/metabolismo , Péptidos beta-Amiloides/metabolismo , Fagocitosis/efectos de los fármacos , Humanos , Fosforilación/efectos de los fármacos , Tirosina/metabolismo , Lipoilación/efectos de los fármacos , Células Cultivadas , Enfermedad de Alzheimer/metabolismo , Cannabidiol/farmacología , Ratones Endogámicos C57BL , Canales de CalcioRESUMEN
In neurodegeneration, neurons release lipids that accumulate in glial lipid droplets (LDs). But what controls lipid transport and how does this affect glia? A recent study by Li et al. discovered that the loss of neuronal AMP-activated protein kinase (AMPK) activity promotes lipid efflux, which drives a proinflammatory state in microglia.
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Proteínas Quinasas Activadas por AMP , Microglía , Neuronas , Animales , Humanos , Proteínas Quinasas Activadas por AMP/metabolismo , Transporte Biológico , Gotas Lipídicas/metabolismo , Metabolismo de los Lípidos , Microglía/metabolismo , Neuronas/metabolismo , RatonesRESUMEN
OBJECTIVE: To investigate the mechanism underlying the neuroprotective effect of linarin (LIN) against microglia activation-mediated inflammation and neuronal apoptosis following spinal cord injury (SCI). METHODS: Fifty C57BL/6J mice (8- 10 weeks old) were randomized to receive sham operation, SCI and linarin treatment at 12.5, 25, and 50 mg/kg following SCI (n=10). Locomotor function recovery of the SCI mice was assessed using the Basso Mouse Scale, inclined plane test, and footprint analysis, and spinal cord tissue damage and myelination were evaluated using HE and LFB staining. Nissl staining, immunofluorescence assay and Western blotting were used to observe surviving anterior horn motor neurons in injured spinal cord tissue. In cultured BV2 cells, the effects of linarin against lipopolysaccharide (LPS)induced microglia activation, inflammatory factor release and signaling pathway changes were assessed with immunofluorescence staining, Western blotting, RT-qPCR, and ELISA. In a BV2 and HT22 cell co-culture system, Western blotting was performed to examine the effect of linarin against HT22 cell apoptosis mediated by LPS-induced microglia activation. RESULTS: Linarin treatment significantly improved locomotor function (P < 0.05), reduced spinal cord damage area, increased spinal cord myelination, and increased the number of motor neurons in the anterior horn of the SCI mice (P < 0.05). In both SCI mice and cultured BV2 cells, linarin effectively inhibited glial cell activation and suppressed the release of iNOS, COX-2, TNF-α, IL-6, and IL-1ß, resulting also in reduced neuronal apoptosis in SCI mice (P < 0.05). Western blotting suggested that linarin-induced microglial activation inhibition was mediated by inhibition of the TLR4/NF- κB signaling pathway. In the cell co-culture experiments, linarin treatment significantly decreased inflammation-mediated apoptosis of HT22 cells (P < 0.05). CONCLUSION: The neuroprotective effect of linarin is medicated by inhibition of microglia activation via suppressing the TLR4/NFκB signaling pathway, which mitigates neural inflammation and reduce neuronal apoptosis to enhance motor function of the SCI mice.
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Apoptosis , Ratones Endogámicos C57BL , Microglía , FN-kappa B , Transducción de Señal , Traumatismos de la Médula Espinal , Receptor Toll-Like 4 , Animales , Ratones , Traumatismos de la Médula Espinal/tratamiento farmacológico , Traumatismos de la Médula Espinal/metabolismo , Microglía/efectos de los fármacos , Microglía/metabolismo , Receptor Toll-Like 4/metabolismo , Apoptosis/efectos de los fármacos , FN-kappa B/metabolismo , Transducción de Señal/efectos de los fármacos , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Fármacos Neuroprotectores/farmacología , Cumarinas/farmacología , Inflamación/metabolismo , Lipopolisacáridos , Enfermedades Neuroinflamatorias/tratamiento farmacológico , Enfermedades Neuroinflamatorias/etiología , GlicósidosRESUMEN
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.
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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
The conditions supporting the generation of microglia-like cells in the central nervous system (CNS) after transplantation of hematopoietic stem/progenitor cells (HSPC) have been studied to advance the treatment of neurodegenerative disorders. Here, we explored the transplantation efficacy of different cell subsets and delivery routes with the goal of favoring the establishment of a stable and exclusive engraftment of HSPCs and their progeny in the CNS of female mice. In this setting, we show that the CNS environment drives the expansion, distribution and myeloid differentiation of the locally transplanted cells towards a microglia-like phenotype. Intra-CNS transplantation of HSPCs engineered to overexpress TREM2 decreased neuroinflammation, Aß aggregation and improved memory in 5xFAD female mice. Our proof of concept study demonstrates the therapeutic potential of HSPC gene therapy for Alzheimer's disease.
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Enfermedad de Alzheimer , Modelos Animales de Enfermedad , Terapia Genética , Trasplante de Células Madre Hematopoyéticas , Células Madre Hematopoyéticas , Ratones Transgénicos , Microglía , Animales , Enfermedad de Alzheimer/terapia , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Terapia Genética/métodos , Femenino , Trasplante de Células Madre Hematopoyéticas/métodos , Ratones , Microglía/metabolismo , Células Madre Hematopoyéticas/metabolismo , Receptores Inmunológicos/genética , Receptores Inmunológicos/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Péptidos beta-Amiloides/metabolismo , Diferenciación Celular , Humanos , Ratones Endogámicos C57BLRESUMEN
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.
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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
There is an urgent need for effective disease-modifying therapeutic interventions for Alzheimer's disease (AD)-the most prevalent cause of dementia with a profound socioeconomic burden. Most clinical trials targeting the classical hallmarks of this disease-ß-amyloid plaques and neurofibrillary tangles-failed, showed discrete clinical effects, or were accompanied by concerning side effects. There has been an ongoing search for novel therapeutic targets. Neuroinflammation, now widely recognized as a hallmark of all neurodegenerative diseases, has been proven to be a major contributor to AD pathology. Here, we summarize the role of neuroinflammation in the pathogenesis and progression of AD and discuss potential targets such as microglia, TREM2, the complement system, inflammasomes, and cytosolic DNA sensors. We also present an overview of ongoing studies targeting specific innate immune system components, highlighting the progress in this field of drug research while bringing attention to the delicate nature of innate immune modulations in AD.
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Enfermedad de Alzheimer , Inmunidad Innata , Enfermedad de Alzheimer/inmunología , Humanos , Animales , Microglía/inmunología , Microglía/metabolismo , Inflamasomas/metabolismo , Inflamasomas/inmunología , Terapia Molecular Dirigida , Glicoproteínas de Membrana , Receptores InmunológicosRESUMEN
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.