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1.
Oxid Med Cell Longev ; 2022: 4564471, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35308167

RESUMO

The polarization of microglia is recognized as a crucial factor in reducing neuroinflammation and promoting hematoma clearance after intracerebral hemorrhage (ICH). Previous studies have revealed that redox components participate in the regulation of microglial polarization. Recently, the novel Nrf2 activator omaveloxolone (Omav) has been validated to improve neurological function in patients with neurodegenerative disorders by regulating antioxidant responses. In this study, we examined the efficacy of Omav in ICH. Omav significantly promoted Nrf2 nuclear accumulation and the expression of HO-1 and NQO1 in BV2 cells. In addition, both in vitro and in vivo experiments showed that Omav treatment inhibited M1-like activation and promoted the activation of the M2-like microglial phenotype. Omav inhibited OxyHb-induced ROS generation and preserved the function of mitochondria in BV2 cells. Intraperitoneal administration of Omav improved sensorimotor function in the ICH mouse model. Importantly, these effects were blocked by pretreatment with ML385, a selective inhibitor of Nrf2. Collectively, Omav modulated microglial polarization by activating Nrf2 and inhibiting ROS generation in ICH models, suggesting that it might be a promising drug candidate for the treatment of ICH.


Assuntos
Lesões Encefálicas , Microglia , Animais , Lesões Encefálicas/tratamento farmacológico , Hemorragia Cerebral/complicações , Hemorragia Cerebral/tratamento farmacológico , Hemorragia Cerebral/metabolismo , Humanos , Camundongos , Microglia/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Fenótipo , Triterpenos
2.
Mediators Inflamm ; 2022: 7924199, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36046763

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disease that primarily manifests as memory deficits and cognitive impairment and has created health challenges for patients and society. In AD, amyloid ß-protein (Aß) induces Toll-like receptor 4 (TLR4) activation in microglia. Activation of TLR4 induces downstream signaling pathways and promotes the generation of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß), which also trigger the activation of astrocytes and influence amyloid-dependent neuronal death. Therefore, TLR4 may be an important molecular target for treating AD by regulating neuroinflammation. Moreover, TLR4 regulates apoptosis, autophagy, and gut microbiota and is closely related to AD. This article reviews the role of TLR4 in the pathogenesis of AD and a range of potential therapies targeting TLR4 for AD. Elucidating the regulatory mechanism of TLR4 in AD may provide valuable clues for developing new therapeutic strategies for AD.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Humanos , Microglia/metabolismo , Doenças Neurodegenerativas/metabolismo , Receptor 4 Toll-Like/metabolismo
3.
J Transl Med ; 20(1): 388, 2022 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-36058942

RESUMO

BACKGROUND: Radiotherapy is the primary therapeutic option for glioblastoma. Some studies proved that radiotherapy increased the release of exosomes from cells. The mechanism by which these exosomes modify the phenotype of microglia in the tumor microenvironment to further determine the fate of irradiated glioblastoma cells remains to be elucidated. METHODS: We erected the co-culture system of glioblastoma cells and microglia. After radiation, we analyzing the immunophenotype of microglia and the proliferation of radiated glioblastoma cells. By whole transcriptome sequencing, we analyzed of circRNAs in exosomes from glioblastoma cells and microglia. We used some methods, which included RT-PCR, dual-luciferase reporter, et al., to identify how circ_0012381 from radiated glioblastoma cell-derived exosomes regulated the immunophenotype of microglia to further affect the proliferation of radiated glioblastoma cells. RESULTS: Radiated glioblastoma cell-derived exosomes markedly induced M2 microglia polarization. These M2-polarized microglia promoted the proliferation of irradiated glioblastoma cells. Circ_0012381 expression was increased in the irradiated glioblastoma cells, and circ_0012381 entered the microglia via exosomes. Circ_0012381 induced M2 microglia polarization by sponging with miR-340-5p to increase ARG1 expression. M2-polarized microglia suppressed phagocytosis and promoted the growth of the irradiated glioblastoma cells by CCL2/CCR2 axis. Compared with the effects of radiotherapy alone, the inhibition of exosomes significantly inhibited the growth of irradiated glioblastoma cells in a zebrafish model. CONCLUSIONS: Our data suggested that the inhibition of exosome secretion might represent a potential therapeutic strategy to increase the efficacy of radiotherapy in patients with glioblastoma.


Assuntos
Exossomos , Glioblastoma , MicroRNAs , Animais , Exossomos/metabolismo , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/radioterapia , MicroRNAs/genética , MicroRNAs/metabolismo , Microglia/metabolismo , Microambiente Tumoral , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
4.
Ecotoxicol Environ Saf ; 241: 113824, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36068751

RESUMO

Manganese (Mn) is an essential cofactor for many enzymes and plays an important role in normal growth and development. However, excess exposure to manganese (Mn) may be an important environmental factor leading to neurodegeneration. The overexpression of microglial cyclooxygenase-2 (COX-2) plays a key role in neuroinflammation in neurodegenerative diseases. The existing data suggest that Mn can induce neuroinflammation by up-regulating COX-2 expression. However, the mechanisms involved in Mn-induced microglial COX-2 up-regulation remain to be determined. The aim of this study was to investigate the role of p53 in Mn-induced COX-2 expression in microglial cells. The results showed that Mn exposure induced the up-regulation of COX-2 and inhibited the expression of p53 in BV2 microglial cells. The addition of p53 activator and the over-expression of p53 blocked the expression of COX-2 and prostaglandin E2 (PGE2), a COX-2 downstream effector, induced by Mn. Further, Mn increased the methylation of p53 DNA in microglia, while the addition of demethylation reagent 5-Aza-dC enhanced the expression of p53 but decreased the expression of COX-2. These results suggested that Mn may inhibit p53 expression through induction of DNA methylation, which can further induce the expression of COX-2 in microglial cells.


Assuntos
Manganês , Microglia , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Lipopolissacarídeos/farmacologia , Manganês/metabolismo , Manganês/toxicidade , Metilação , Microglia/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
6.
Biomed Pharmacother ; 153: 113412, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36076537

RESUMO

Microglia, resident macrophages that act as the brain's innate immune cells, play a key role in initiating a defense response to the infection or neuroinflammation of the host. Once a broad spectrum of dangers is confronted, microglia get triggered and transform their role against immune stimuli. Recent studies have shown that remarkable metabolic changes present in activated microglia affect their immune function. Given that the important role of microglia in the progression of neurodegeneration is widely recognized, it is crucial to know whether metabolic reprogramming of microglia also presents in neurodegeneration and how this may influence their role in neurodegeneration progression. This paper provides an overview of the metabolic reprogramming of microglia, the major pathways involved in recent advances in five major neurodegenerative diseases of aging (NDAs), including Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD), etc. And then we elucidated their impacts on the disease progression of neurodegeneration. Furthermore, growing evidence suggests that microbiota-derived metabolites, including acetate, N6-carboxymethyllysine (CML), and isoamylamine (IAA), regulate metabolic pathways and functions of microglia, and play a crucial role in cellular homeostasis. We shed light on this topic and concluded these metabolites are potential therapeutic targets for NDAs.


Assuntos
Esclerose Amiotrófica Lateral , Doenças Neurodegenerativas , Doença de Parkinson , Humanos , Macrófagos , Microglia/metabolismo , Doenças Neurodegenerativas/metabolismo , Doença de Parkinson/metabolismo
7.
J Neuroinflammation ; 19(1): 229, 2022 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-36115971

RESUMO

BACKGROUND: Dysfunctional humoral and cellular innate immunity are key components in the development and progression of age-related macular degeneration (AMD). Specifically, chronically activated microglia and their disturbed regulatory system contribute to retinal degeneration. Galectin-3, a ß-galactose binding protein, is a potent driver of macrophage and microglia activation and has been implicated in neuroinflammation, including neurodegenerative diseases of the brain. Here, we hypothesized that genetic deficiency of galectin-3 or its modulation via TD139 dampens mononuclear phagocyte reactivity and delays retinal degeneration. METHODS: Galectin-3 expression in AMD patients was analyzed by immunohistochemical stainings. Galectin-3 knockout and BALB/cJ mice were exposed to white bright light with an intensity of 15,000 lux for 1 h and Cx3cr1GFP/+ mice to focal blue light of 50,000 lux for 10 min. BALB/cJ and Cx3cr1GFP/+ mice received intraperitoneal injections of 15 mg/kg TD139 or vehicle for five consecutive days, starting one day prior to light exposure. The effects of galectin-3 deficiency or inhibition on microglia were analyzed by immunohistochemical stainings and in situ hybridization of retinal sections and flat mounts. Pro-inflammatory cytokine levels in the retina and retinal pigment epithelium (RPE) were quantified by qRT-PCR and transcriptomic changes were analyzed by RNA-sequencing. Retinal thickness and structure were evaluated by optical coherence tomography. RESULTS: We found that galectin-3 expression was strongly upregulated in reactive retinal mononuclear phagocytes of AMD patients and in the two related mouse models of light-induced retinal degeneration. The experimental in vivo data further showed that specific targeting of galectin-3 by genetic knockout or administration of the small-molecule inhibitor TD139 reduced microglia reactivity and delayed retinal damage in both light damage conditions. CONCLUSION: This study defines galectin-3 as a potent driver of retinal degeneration and highlights the protein as a drug target for ocular immunomodulatory therapies.


Assuntos
Degeneração Macular , Degeneração Retiniana , Animais , Citocinas/metabolismo , Galactose/metabolismo , Galectina 3/genética , Degeneração Macular/metabolismo , Camundongos , Microglia/metabolismo , RNA/metabolismo , Degeneração Retiniana/metabolismo , Tiogalactosídeos , Triazóis
8.
Front Immunol ; 13: 945485, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36105813

RESUMO

Microglia are phagocytosis-competent CNS cells comprising a spectrum of subtypes with beneficial and/or detrimental functions in acute and chronic neurodegenerative disorders. The heterogeneity of microglia suggests differences in phagocytic activity and phenotype plasticity between microglia subtypes. To study these issues, primary murine glial cultures were cultivated in the presence of serum, different growth factors and cytokines to obtain M0-like, M1-like, and M2-like microglia as confirmed by morphology, M1/M2 gene marker expression, and nitric oxide assay. Single-cell analysis after 3 hours of phagocytosis of E.coli particles or IgG-opsonized beads showed equal internalization by M0-like microglia, whereas M1-like microglia preferably internalized E.coli particles and M2-like microglia preferably internalized IgG beads, suggesting subtype-specific preferences for different phagocytosis substrates. Time-lapse live-cells imaging over 16 hours revealed further differences between microglia subtypes in phagocytosis preference and internalization dynamics. M0- and, more efficiently, M1-like microglia continuously internalized E.coli particles for 16 hours, whereas M2-like microglia discontinued internalization after approximately 8 hours. IgG beads were continuously internalized by M0- and M1-like microglia but strikingly less by M2-like microglia. M2-like microglia initially showed continuous internalization similar to M0-like microglia but again discontinuation of internalization after 8 hours suggesting that the time of substrate exposure differently affect microglia subtypes. After prolonged exposure to E.coli particles or IgG beads for 5 days all microglia subtypes showed increased internalization of E.coli particles compared to IgG beads, increased nitric oxide release and up-regulation of M1 gene markers, irrespectively of the phagocytosis substrate, suggesting phenotype plasticity. In summary, microglia subtypes show substrate- and time-dependent phagocytosis preferences and phenotype plasticity. The results suggest that prolonged phagocytosis substrate exposure enhances M1-like profiles and M2-M1 repolarization of microglia. Similar processes may also take place in conditions of acute and chronic brain insults when microglia encounter different types of phagocytic substrates.


Assuntos
Microglia , Óxido Nítrico , Animais , Imunoglobulina G/metabolismo , Camundongos , Microglia/metabolismo , Óxido Nítrico/metabolismo , Fagocitose , Fenótipo
9.
J Exp Med ; 219(12)2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36107206

RESUMO

TREM2 is exclusively expressed by microglia in the brain and is strongly linked to the risk for Alzheimer's disease (AD). As microglial responses modulated by TREM2 are central to AD pathogenesis, enhancing TREM2 signaling has been explored as an AD therapeutic strategy. However, the effective therapeutic window targeting TREM2 is unclear. Here, by using microglia-specific inducible mouse models overexpressing human wild-type TREM2 (TREM2-WT) or R47H risk variant (TREM2-R47H), we show that TREM2-WT expression reduces amyloid deposition and neuritic dystrophy only during the early amyloid seeding stage, whereas TREM2-R47H exacerbates amyloid burden during the middle amyloid rapid growth stage. Single-cell RNA sequencing reveals suppressed disease-associated microglia (DAM) signature and reduced DAM population upon TREM2-WT expression in the early stage, whereas upregulated antigen presentation pathway is detected with TREM2-R47H expression in the middle stage. Together, our findings highlight the dynamic effects of TREM2 in modulating AD pathogenesis and emphasize the beneficial effect of enhancing TREM2 function in the early stage of AD development.


Assuntos
Doença de Alzheimer , Amiloidose , Doença de Alzheimer/patologia , Amiloide/metabolismo , Amiloidose/patologia , Animais , Encéfalo/patologia , Humanos , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Microglia/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo
10.
Front Immunol ; 13: 976729, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36119027

RESUMO

Inflammation plays a pivotal role in ischemia-induced retinal neovascularization. Targeting microglia/macrophage-based neuroinflammation presents a promising therapeutic strategy. Ferulic acid (FA), a natural and active ingredient in plants, exerts favorable anti-oxidative and anti-inflammatory activities. In this study, we investigated the inhibitory effect of FA against hypoxia-induced retinal angiogenesis using cultured retinal vascular endothelial cells and an oxygen-induced retinopathy mouse (OIR) model. The immunoregulatory effect of FA on microglia/macrophage polarization was evaluated by detecting the expression of specific markers for both pro-inflammatory "M1" and anti-inflammatory "M2" phenotypes using co-immunostaining and polymerase chain reaction assays. The underlying molecular mechanism upon FA treatment was also explored. The results showed that FA supplement markedly inhibited retinal pathological angiogenesis both in vivo and in vitro. In addition, FA switched microglia/macrophage polarization from "M1" towards "M2" phenotype and alleviated the inflammatory response. Mechanically, the anti-angiogenic and anti-inflammatory properties of FA were mainly due to blockade of the ROS/NF-κB pathway. Our data demonstrated an anti-angiogenic effect of FA through regulating M1-to-M2 microglia/macrophage polarization, suggesting a potential therapeutic strategy for retinal neovascular diseases.


Assuntos
Microglia , Neovascularização Retiniana , Animais , Anti-Inflamatórios/metabolismo , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Ácidos Cumáricos , Modelos Animais de Doenças , Células Endoteliais , Macrófagos , Camundongos , Microglia/metabolismo , NF-kappa B/metabolismo , Oxigênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Neovascularização Retiniana/tratamento farmacológico , Neovascularização Retiniana/patologia
11.
Front Immunol ; 13: 942768, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36119084

RESUMO

Diabetic retinopathy (DR) is the leading cause of visual impairment and blindness among working-age people. Inflammation is recognized as a critical driver of the DR process. However, the main retina-specific cell type producing pro-inflammatory cytokines and its mechanism underlying DR are still unclear. Here, we used single-cell sequencing to identify microglia with metabolic pathway alterations that were the main source of IL-1ß in STZ-induced DR mice. To profile the full extent of local metabolic shifts in activated microglia and to reveal the metabolic microenvironment contributing to immune mechanisms, we performed integrated metabolomics, lipidomics, and RNA profiling analyses in microglia cell line samples representative of the DR microenvironment. The results showed that activated microglia with IL-1ß increase exhibited a metabolic bias favoring glycolysis, purine metabolism, and triacylglycerol synthesis, but less Tricarboxylic acid (TCA). In addition, some of these especially glycolysis was necessary to facilitate their pro-inflammation. These findings suggest that activated microglia with intracellular metabolic reprogramming in retina may contribute to pro-inflammation in the early DR.


Assuntos
Diabetes Mellitus , Retinopatia Diabética , Animais , Citocinas/metabolismo , Diabetes Mellitus/metabolismo , Humanos , Inflamação/metabolismo , Camundongos , Microglia/metabolismo , Purinas/metabolismo , RNA/metabolismo , Retina/metabolismo , Ácidos Tricarboxílicos/metabolismo , Triglicerídeos/metabolismo
12.
Int J Oral Sci ; 14(1): 44, 2022 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-36064768

RESUMO

Traumatic brain injury (TBI) contributes to the key causative elements of neurological deficits. However, no effective therapeutics have been developed yet. In our previous work, extracellular vesicles (EVs) secreted by stem cells from human exfoliated deciduous teeth (SHED) offered new insights as potential strategies for functional recovery of TBI. The current study aims to elucidate the mechanism of action, providing novel therapeutic targets for future clinical interventions. With the miRNA array performed and Real-time PCR validated, we revealed the crucial function of miR-330-5p transferred by SHED-derived EVs (SHED-EVs) in regulating microglia, the critical immune modulator in central nervous system. MiR-330-5p targeted Ehmt2 and mediated the transcription of CXCL14 to promote M2 microglia polarization and inhibit M1 polarization. Identified in our in vivo data, SHED-EVs and their effector miR-330-5p alleviated the secretion of inflammatory cytokines and resumed the motor functional recovery of TBI rats. In summary, by transferring miR-330-5p, SHED-EVs favored anti-inflammatory microglia polarization through Ehmt2 mediated CXCL14 transcription in treating traumatic brain injury.


Assuntos
Lesões Encefálicas Traumáticas , Quimiocinas CXC , Vesículas Extracelulares , Histona-Lisina N-Metiltransferase , MicroRNAs , Microglia , Animais , Lesões Encefálicas Traumáticas/genética , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/terapia , Quimiocinas CXC/genética , Quimiocinas CXC/metabolismo , Vesículas Extracelulares/genética , Vesículas Extracelulares/metabolismo , Antígenos de Histocompatibilidade/genética , Antígenos de Histocompatibilidade/metabolismo , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Microglia/metabolismo , Ratos , Células-Tronco/metabolismo
13.
PLoS Pathog ; 18(9): e1010637, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36067217

RESUMO

Toxoplasma gondii is a ubiquitous intracellular protozoan parasite that establishes a life-long chronic infection largely restricted to the central nervous system (CNS). Constant immune pressure, notably IFN-γ-STAT1 signaling, is required for preventing fatal pathology during T. gondii infection. Here, we report that abrogation of STAT1 signaling in microglia, the resident immune cells of the CNS, is sufficient to induce a loss of parasite control in the CNS and susceptibility to toxoplasmic encephalitis during the early stages of chronic infection. Using a microglia-specific genetic labeling and targeting system that discriminates microglia from blood-derived myeloid cells that infiltrate the brain during infection, we find that, contrary to previous in vitro reports, microglia do not express inducible nitric-oxide synthase (iNOS) during T. gondii infection in vivo. Instead, transcriptomic analyses of microglia reveal that STAT1 regulates both (i) a transcriptional shift from homeostatic to "disease-associated microglia" (DAM) phenotype conserved across several neuroinflammatory models, including T. gondii infection, and (ii) the expression of anti-parasitic cytosolic molecules that are required for eliminating T. gondii in a cell-intrinsic manner. Further, genetic deletion of Stat1 from microglia during T. gondii challenge leads to fatal pathology despite largely equivalent or enhanced immune effector functions displayed by brain-infiltrating immune populations. Finally, we show that microglial STAT1-deficiency results in the overrepresentation of the highly replicative, lytic tachyzoite form of T. gondii, relative to its quiescent, semi-dormant bradyzoite form typical of chronic CNS infection. Our data suggest an overall protective role of CNS-resident microglia against T. gondii infection, illuminating (i) general mechanisms of CNS-specific immunity to infection (ii) and a clear role for IFN-STAT1 signaling in regulating a microglial activation phenotype observed across diverse neuroinflammatory disease states.


Assuntos
Encefalite , Toxoplasma , Toxoplasmose Cerebral , Encéfalo/patologia , Encefalite/metabolismo , Encefalite/patologia , Humanos , Microglia/metabolismo , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/metabolismo , Toxoplasma/metabolismo , Toxoplasmose Cerebral/metabolismo
14.
Acta Neuropathol Commun ; 10(1): 136, 2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-36076283

RESUMO

Single cell RNA sequencing studies identified novel neurodegeneration-associated microglial (MGnD/DAM) subtypes activated around cerebral amyloid plaques. Micro-RNA (miR)-155 of the TREM2-APOE pathway was shown to be a key transcriptional regulator of MGnD microglial phenotype. Despite growing interest in studying manifestations of Alzheimer's disease (AD) in the retina, a CNS organ accessible to noninvasive high-resolution imaging, to date MGnD microglia have not been studied in the AD retina. Here, we discovered the presence and increased populations of Clec7a+ and Galectin-3+ MGnD microglia in retinas of transgenic APPSWE/PS1L166P AD-model mice. Conditionally targeting MGnD microglia by miR-155 ablation via the tamoxifen-inducible CreERT2 system in APPSWE/PS1L166P mice diminished retinal Clec7a+ and Galectin-3+ microglial populations while increasing homeostatic P2ry12+ microglia. Retinal MGnD microglia were often adhering to microvessels; their depletion protected the inner blood-retina barrier and reduced vascular amyloidosis. Microglial miR-155 depletion further limits retinal inflammation. Mass spectrometry analysis revealed enhanced retinal PI3K-Akt signaling and predicted IL-8 and Spp1 decreases in mice with microglia-specific miR-155 knockout. Overall, this study identified MGnD microglia in APPSWE/PS1L166P mouse retina. Transcriptional regulation of these dysfunctional microglia mitigated retinal inflammation and vasculopathy. The protective effects of microglial miR-155 ablation should shed light on potential treatments for retinal inflammation and vascular damage during AD and other ocular diseases.


Assuntos
Doença de Alzheimer , MicroRNAs , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Animais , Modelos Animais de Doenças , Galectina 3/genética , Galectina 3/metabolismo , Inflamação/metabolismo , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , MicroRNAs/genética , MicroRNAs/metabolismo , Microglia/metabolismo , Fenótipo , Fosfatidilinositol 3-Quinases/genética , Receptores Imunológicos/metabolismo
15.
Int J Mol Sci ; 23(17)2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36077227

RESUMO

The sex and APOE4 genotype are significant risk factors for Alzheimer's disease (AD); however, the mechanism(s) responsible for this interaction are still a matter of debate. Here, we assess the responses of mixed-sex and sex-specific APOE3 and APOE4 primary microglia (PMG) to lipopolysaccharide and interferon-gamma. In our investigation, inflammatory cytokine profiles were assessed by qPCR and multiplex ELISA assays. Mixed-sex APOE4 PMG exhibited higher basal mRNA expression and secreted levels of TNFa and IL1b. In sex-specific cultures, basal expression and secreted levels of IL1b, TNFa, IL6, and NOS2 were 2-3 fold higher in APOE4 female PMG compared to APOE4 males, with both higher than APOE3 cells. Following an inflammatory stimulus, the expression of pro-inflammatory cytokines and the secreted cytokine level were upregulated in the order E4 female > E4 male > E3 female > E3 male in sex-specific cultures. These data indicate that the APOE4 genotype and female sex together contribute to a greater inflammatory response in PMG isolated from targeted replacement humanized APOE mice. These data are consistent with clinical data and indicate that sex-specific PMG may provide a platform for exploring mechanisms of genotype and sex differences in AD related to neuroinflammation and neurodegeneration.


Assuntos
Doença de Alzheimer , Apolipoproteína E4 , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Animais , Apolipoproteína E3/genética , Apolipoproteína E3/metabolismo , Apolipoproteína E4/genética , Apolipoproteína E4/metabolismo , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Citocinas/metabolismo , Feminino , Genótipo , Masculino , Camundongos , Camundongos Transgênicos , Microglia/metabolismo
16.
Sci Rep ; 12(1): 15273, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-36088481

RESUMO

Mutations in the Membrane-type frizzled related protein (Mfrp) gene results in an early-onset retinal degeneration associated with retinitis pigmentosa, microphthalmia, optic disc drusen and foveal schisis. In the current study, a previously characterized mouse model of human retinal degeneration carrying homozygous c.498_499insC mutations in Mfrp (MfrpKI/KI) was used. Patients carrying this mutation have retinal degeneration at an early age. The model demonstrates subretinal deposits and develops early-onset photoreceptor degeneration. We observed large subretinal deposits in MfrpKI/KI mice which were strongly CD68 positive and co-localized with autofluorescent spots. Single cell RNA sequencing of MfrpKI/KI mice retinal microglia showed a significantly higher number of pan-macrophage marker Iba-1 and F4/80 positive cells with increased expression of activation marker (CD68) and lowered microglial homeostatic markers (TMEM119, P2ry13, P2ry13, Siglech) compared with wild type mice confirming microglial activation as observed in retinal immunostaining showing microglia activation in subretinal region. Trajectory analysis identified a small cluster of microglial cells with activation transcriptomic signatures that could represent a subretinal microglia population in MfrpKI/KI mice expressing higher levels of APOE. We validated these findings using immunofluorescence staining of retinal cryosections and found a significantly higher number of subretinal Iba-1/ApoE positive microglia in MfrpKI/KI mice with some subretinal microglia also expressing lowered levels of microglial homeostatic marker TMEM119, confirming microglial origin. In summary, we confirm that MfrpKI/KI mice carrying the c.498_499insC mutation had a significantly higher population of activated microglia in their retina with distinct subsets of subretinal microglia. Further, studies are required to confirm whether the association of increased subretinal microglia in MfrpKI/KI mice are causal in degeneration.


Assuntos
Degeneração Retiniana , Animais , Apolipoproteínas E/genética , Fóvea Central/metabolismo , Humanos , Proteínas de Membrana/metabolismo , Camundongos , Microglia/metabolismo , Degeneração Retiniana/genética , Degeneração Retiniana/metabolismo , Análise de Sequência de RNA
17.
Stem Cell Res Ther ; 13(1): 470, 2022 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-36089602

RESUMO

BACKGROUND: We previously established a human mesenchymal stem cell (MSC) line that was modified to express trophic factors. Transplanting a cell sheet produced from this line in an amyotrophic lateral sclerosis mouse model showed a beneficial trend for mouse life spans. However, the sheet survived for less than 14 days, and numerous microglia and macrophages were observed within and adjacent to the sheet. Here, we examined the roles of microglia and macrophages as well as acquired antibodies in cell sheet transplantation. METHODS: We observed the effects of several MSC lines on macrophages in vitro, that is, phenotype polarization (M1 or M2) and migration. We then investigated how phenotypic polarization affected MSC survival using antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). We also confirmed the role of complement on cytotoxicity. Lastly, we selectively eliminated microglia and macrophages in vivo to determine whether these cells were cytoprotective to the donor sheet. RESULTS: In vitro co-culture with MSCs induced M2 polarization in macrophages and facilitated their migration toward MSCs in vitro. There was no difference between M1 and M2 phenotypes on ADCC and ADCP. Cytotoxicity was observed even in the absence of complement. Eliminating microglia/macrophage populations in vivo resulted in increased survival of donor cells after transplantation. CONCLUSIONS: Acquired antibodies played a role in ADCC and ADCP. MSCs induced M2 polarization in macrophages and facilitated their migration toward MSCs in vitro. Despite these favorable characteristics of microglia and macrophages, deletion of these cells was advantageous for the survival of donor cells in vivo.


Assuntos
Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Animais , Sistema Nervoso Central , Humanos , Macrófagos , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/metabolismo , Camundongos , Microglia/metabolismo
18.
Commun Biol ; 5(1): 841, 2022 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-35986097

RESUMO

Vascular occlusion leading to brain dysfunctions is usually considered evoking microglia-induced inflammation response. However, it remains unclear how microglia interact with blood vessels in the development of vascular occlusion-related brain disorders. Here, we illuminate long-term spatiotemporal dynamics of microglia during single vessel occlusion and recanalization. Microglia display remarkable response characteristics in different phases, including acute reaction, rapid diffusion, transition and chronic effect. Fibrinogen-induced microglial cluster promotes major histocompatibility complex II (MHCII) expression. Microglial soma represents a unique filament-shape migration and has slower motility compared to the immediate reaction of processes to occlusion. We capture proliferative microglia redistribute territory. Microglial cluster resolves gradually and microglia recover to resting state both in the morphology and function in the chronic effect phase. Therefore, our study offers a comprehensive analysis of spatiotemporal dynamics of microglia and potential mechanisms to both vessel occlusion and recanalization. Microglial phase-specific response suggests the morphological feature-oriented phased intervention would be an attractive option for vascular occlusion-related diseases treatments.


Assuntos
Encéfalo , Microglia , Microglia/metabolismo
19.
Int J Mol Sci ; 23(16)2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-36012150

RESUMO

Microglia, the resident innate immune cells of the brain, become more highly reactive with aging and diseased conditions. In collaboration with other cell types in brains, microglia can contribute both to worsened outcome following stroke or other neurodegenerative diseases and to the recovery process by changing their phenotype toward reparative microglia. Recently, IFITM3 (a member of the "interferon-inducible transmembrane" family) has been revealed as a molecular mediator between amyloid pathology and neuroinflammation. Expression of IFITM3 in glial cells, especially microglia following stroke, is not well described. Here, we present evidence that ischemic stroke causes an increase in IFITM3 expression along with increased microglial activation marker genes in aged brains. To further validate the induction of IFITM3 in post-stroke brains, primary microglia and microglial-like cells were exposed to a variety of inflammatory conditions, which significantly induced IFITM3 as well as other inflammatory markers. These findings suggest the critical role of IFITM3 in inducing inflammation. Our findings on the expression of IFITM3 in microglia and in aged brains following stroke could establish the basic foundations for the role of IFITM3 in a variety of neurodegenerative diseases, particularly those that are prevalent or enhanced in the aged brain.


Assuntos
Doenças Neurodegenerativas , Acidente Vascular Cerebral , Biomarcadores/metabolismo , Encéfalo/metabolismo , Humanos , Interferons/metabolismo , Proteínas de Membrana/metabolismo , Microglia/metabolismo , Doenças Neurodegenerativas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Acidente Vascular Cerebral/metabolismo
20.
Int J Mol Sci ; 23(16)2022 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-36012189

RESUMO

BACKGROUND: Microglia are key cells of the immune system in the central nervous system and are suggested to be deeply involved in the development of neurodegenerative diseases. It is well known that microglia have functional plasticity, with an inflammatory M1 phenotype and an anti-inflammatory M2 phenotype. Inhibition of choline transport in macrophages has been reported to suppress the secretion of inflammatory cytokines. However, the role of the choline transport system in regulating microglial M1/M2 polarization has not been fully elucidated to date. In this study, we investigated the mechanism of choline uptake in microglia, and its association with microglial M1/M2 polarization. METHODS: The immortalized mouse microglial cell line SIM-A9 was used for [3H]choline uptake and expression analysis of choline transporters. The association between the choline uptake system and the M1/M2 polarization of microglia was also analyzed. RESULTS: Choline transporter-like protein (CTL) 1 and CTL2 were highly expressed in SIM-A9 cells, and CTL1 and CTL2 were localized in the plasma membrane and mitochondria, respectively. Functional analysis of choline uptake demonstrated the existence of Na+-independent, pH-dependent, and intermediate-affinity choline transport systems. Choline uptake was concentration-dependently inhibited by hemicholinium-3 (HC-3), an inhibitor of choline uptake, and increased by lipopolysaccharide (LPS) and interleukin-4 (IL-4). Expression of the mRNA of M1 microglia markers IL-1ß and IL-6 was increased by LPS, and their effects were suppressed by choline deprivation and HC-3. In contrast, mRNA expression of the M2 microglial marker arginase-1 (Arg-1) was increased by IL-4, and the effect was enhanced by choline deprivation and HC-3. CONCLUSIONS: Our results suggest that inhibition of CTL1-mediated choline uptake in microglia preferentially induces M2 microglia polarization, which is a potential therapeutic approach for inflammatory brain diseases.


Assuntos
Lipopolissacarídeos , Microglia , Animais , Polaridade Celular , Colina/metabolismo , Interleucina-4/metabolismo , Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/farmacologia , Proteínas de Membrana Transportadoras , Camundongos , Microglia/metabolismo , Proteínas de Transporte de Cátions Orgânicos/genética , Proteínas de Transporte de Cátions Orgânicos/metabolismo , RNA Mensageiro/metabolismo
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