scholarly journals Rapamycin Modulates the Proinflammatory Memory-Like Response of Microglia Induced by BAFF

2021 ◽  
Vol 12 ◽  
Author(s):  
Jianing Wang ◽  
Chunshu Yang ◽  
Xiaoyu Hou ◽  
Jingyi Xu ◽  
Yang Yun ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Adaptive Immune System ◽  
Current Data ◽  
Metabolic Reprogramming ◽  
Microglial Cells ◽  
Trained Immunity ◽  
Cytokines And Chemokines ◽  
Bv2 Cells

BackgroundRecently trained immunity of microglia provided an opportunity to study the chronic effect of microglial activation and its metabolic rewiring in neuroimmunological diseases. Since elevated levels of B cell-activating factor (BAFF) have been proved to be associated with some chronic neuroimmunological disorders. Here, we used the trained innate immunity model to analyze the effect of BAFF, a vital regulator of the adaptive immune system, on long-term microglial activation and metabolic reprogramming in vitro and in vivo.Methods and resultsIn vitro, BV2 cells and mouse primary microglial cells were incubated with BAFF for 24 h (BAFF priming). After 5 days of resting, microglia were restimulated with LPS (LPS restimulation) or BAFF (BAFF restimulation). BAFF priming induced a pro-inflammatory trained immunity-phenotype of both BV2 cells and primary microglial cells, which was indicated by morphological change, secretion of pro-inflammatory cytokine and chemokine upon LPS restimulation or BAFF restimulation. The production of lactate and NAD+/NADH ratio were elevated 5 days after BAFF priming. The activation of the Akt/mTOR/HIF-1α pathway was induced by BAFF priming and lasted for 5 days. Pretreating the BV2 cells or mouse primary microglial cells with rapamycin blocked mTOR/HIF-1α activation and cellular metabolic reprogramming induced by BAFF training. Consistently, rapamycin efficiently suppressed the trained immunity-like responses of microglia triggered by BAFF. In vivo, adult male mice were treated withBAFF by intracerebroventricular injection for priming and 7 days later with BAFF for restimulation. BAFF training activated microglia in the cortex and hippocampus. The production of proinflammatory cytokines and chemokines was elevated after BAFF training.ConclusionOur current data, for the first time, demonstrate that BAFF priming induces a proinflammatory memory-like response of microglia not only to LPS but also to BAFF itself. Rapamycin inhibits microglial priming triggered by BAFF through targeting the mTOR/HIF-1α signaling pathway. Our data reveal a novel role of BAFF in trained immunity and that rapamycin may be a potential therapeutic target of neuroimmunological diseases.

scholarly journals Astrocyte-Derived CCL2 is Associated with M1 Activation and Recruitment of Cultured Microglial Cells

2016 ◽  
Vol 38 (3) ◽  
pp. 859-870 ◽  
Author(s):  
Mingfeng He ◽  
Hongquan Dong ◽  
Yahui Huang ◽  
Shunmei Lu ◽  
Shu Zhang ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Microglial Activation ◽  
Culture Media ◽  
Microglial Cells ◽  
Migration Ability ◽  
Migration Assay ◽  
Tnf Α

Background/Aims: Microglia are an essential player in central nervous system inflammation. Recent studies have demonstrated that the astrocytic chemokine, CCL2, is associated with microglial activation in vivo. However, CCL2-induced microglial activation has not yet been studied in vitro. The purpose of the current study was to understand the role of astrocyte-derived CCL2 in microglial activation and to elucidate the underlying mechanism(s). Methods: Primary astrocytes were pre-treated with CCL2 siRNA and stimulated with TNF-α. The culture medium (CM) was collected and added to cultures of microglia, which were incubated with and without CCR2 inhibitor. Microglial cells were analyzed by quantitative RT-PCR to determine whether they polarized to the M1 or M2 state. Microglial migratory ability was assessed by transwell migration assay. Results: TNF-α stimulated the release of CCL2 from astrocytes, even if the culture media containing TNF-α was replaced with fresh media after 3 h. CM from TNF-α-stimulated astrocytes successfully induced microglial activation, which was ascertained by increased activation of M1 and enhanced migration ability. In contrast, CM from astrocytes pretreated with CCL2 siRNA showed no effect on microglial activation, compared to controls. Additionally, microglia pre-treated with RS102895, a CCR2 inhibitor, were resistant to activation by CM from TNF-α-stimulated astrocytes. Conclusion: This study demonstrates that the CCL2/CCR2 pathway of astrocyte-induced microglial activation is associated with M1 polarization and enhanced migration ability, indicating that this pathway could be a useful target to ameliorate inflammation in the central nervous system.

scholarly journals Modulation of Glial Responses by Furanocembranolides: Leptolide Diminishes Microglial Inflammation in Vitro and Ameliorates Gliosis In Vivo in a Mouse Model of Obesity and Insulin Resistance

Marine Drugs ◽  
2020 ◽  
Vol 18 (8) ◽  
pp. 378
Author(s):  
Miriam Corraliza-Gómez ◽  
Amalia B. Gallardo ◽  
Ana R. Díaz-Marrero ◽  
José M. de la Rosa ◽  
Luis D’Croz ◽  
...  
Keyword(s):  
Mouse Model ◽  
Microglial Cells ◽  
Obese Mouse ◽  
Neurodegenerative Process ◽  
Age Related ◽  
Bv2 Cells ◽  
Anti Inflammatory ◽  
Inflammatory Molecules

Neurodegenerative diseases are age-related disorders caused by progressive neuronal death in different regions of the nervous system. Neuroinflammation, modulated by glial cells, is a crucial event during the neurodegenerative process; consequently, there is an urgency to find new therapeutic products with anti-glioinflammatory properties. Five new furanocembranolides (1−5), along with leptolide, were isolated from two different extracts of Leptogorgia sp., and compound 6 was obtained from chemical transformation of leptolide. Their structures were determined based on spectroscopic evidence. These seven furanocembranolides were screened in vitro by measuring their ability to modulate interleukin-1β (IL-1β) production by microglial BV2 cells after LPS (lipopolysaccharide) stimulation. Leptolide and compounds 3, 4 and 6 exhibited clear anti-inflammatory effects on microglial cells, while compound 2 presented a pro-inflammatory outcome. The in vitro results prompted us to assess anti-glioinflammatory effects of leptolide in vivo in a high-fat diet-induced obese mouse model. Interestingly, leptolide treatment ameliorated both microgliosis and astrogliosis in this animal model. Taken together, our results reveal a promising direct biological effect of furanocembranolides on microglial cells as bioactive anti-inflammatory molecules. Among them, leptolide provides us a feasible therapeutic approach to treat neuroinflammation concomitant with metabolic impairment.

scholarly journals Rapid Morphologic and Molecular Activation of Microglial Cells by Stimulation of the P2X7 Receptor Correlates with Neuron Loss

2021 ◽  
Author(s):  
Keith E Campagno ◽  
Wennan Lu ◽  
Assraa Hassan Jassim ◽  
Farraj Albalawi ◽  
Aurora Cenaj ◽  
...  
Keyword(s):  
Cell Body ◽  
Microglial Activation ◽  
Morphological Changes ◽  
Mechanical Strain ◽  
Atp Release ◽  
Microglial Cells ◽  
Microglial Migration ◽  
Process Retraction

Abstract Background: The endogenous signals leading to microglial activation represent central components of neuroinflammatory cascades. Given ATP release accompanies mechanical strain to neural tissue, and the P2X7R for ATP is expressed on microglial cells, we examined the morphological and molecular consequences of P2X7R stimulation in vivo and in vitro in detail to enhance understanding of the response. Methods: IL-1β release was determined with ELISA. Expression of mRNA used qPCR. ATP release was determined with the luciferin/luciferase assay while fura-2 indicated cytoplasmic calcium. Microglial migration used Boyden chambers. Morphological changes were quantified from Iba1-immunostained cells. Results: Sholl analysis of Iba1-stained cells showed retraction of microglial ramifications one day after injection of P2X7R agonist BzATP into mouse retinae. Mean branch length also decreased, while cell body size and expression of Nos2, Tnfa, Arg1, Chil3 increased. BzATP induced similar morphological changes in ex vivo tissue isolated from Cx3CR1-GFP mice, suggesting cell recruitment was unnecessary. Primary microglial cultures were developed to investigate the autonomous nature of the response. Isolated microglial cells expressed P2X7R, while increased intracellular Ca 2+ triggered by BzATP and blocked by antagonist A839977 confirmed functional expression. BzATP induced process retraction and cell body enlargement within minutes in isolated microglial cells, and increased expression of Nos2 and Arg1 . BzATP both increased expression of IL-1β, and triggered a substantial release, suggesting P2X7R both primes and activates the NLRP3 inflammasome. ATP increased microglial migration, but this required P2Y12R, not P2X7R involvement. As ATP release often accompanies mechanical strain, responses to intraocular pressure elevation were determined. Transient elevation increased ATP release and led to microglial process retraction, cell body enlargement and gene upregulation resembling the responses to BzATP injection. These pressure-dependent changes to microglia were reduced in P2X7R -/- mice. Critically, the loss of retinal ganglion cell neurons accompanying increased pressure was correlated with microglial activation in C57Bl/6J, but not P2X7R -/- mice.Conclusions: P2X7R stimulation induced morphological and molecular markers of activation in retinal microglial cells in vivo and in vitro , affecting IL-1β release and rapid process retraction but not cell migration. Parallel responses accompanied transient pressure elevation, suggesting ATP release and P2X7R stimulation contribute to the microglial response to rising pressure.

scholarly journals The H2S Donor GYY4137 Stimulates Reactive Oxygen Species Generation in BV2 Cells While Suppressing the Secretion of TNF and Nitric Oxide

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2966 ◽  
Author(s):  
Milica Lazarević ◽  
Emanuela Mazzon ◽  
Miljana Momčilović ◽  
Maria Basile ◽  
Giuseppe Colletti ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Microglial Cells ◽  
Oxygen Species ◽  
Bv2 Cells ◽  
The Central Nervous System

GYY4137 is a hydrogen sulfide (H2S) donor that has been shown to act in an anti-inflammatory manner in vitro and in vivo. Microglial cells are among the major players in immunoinflammatory, degenerative, and neoplastic disorders of the central nervous system, including multiple sclerosis, Parkinson’s disease, Alzheimer’s disease, and glioblastoma multiforme. So far, the effects of GYY4137 on microglial cells have not been thoroughly investigated. In this study, BV2 microglial cells were stimulated with interferon-gamma and lipopolysaccharide and treated with GYY4137. The agent did not influence the viability of BV2 cells in concentrations up to 200 μM. It inhibited tumor necrosis factor but not interleukin-6 production. Expression of CD40 and CD86 were reduced under the influence of the donor. The phagocytic ability of BV2 cells and nitric oxide production were also affected by the agent. Surprisingly, GYY4137 upregulated generation of reactive oxygen species (ROS) by BV2 cells. The effect was mimicked by another H2S donor, Na2S, and it was not reproduced in macrophages. Our results demonstrate that GYY4137 downregulates inflammatory properties of BV2 cells but increases their ability to generate ROS. Further investigation of this unexpected phenomenon is warranted.

scholarly journals Aquilariae Lignum Methylene Chloride Fraction Attenuates IL-1β-Driven Neuroinflammation in BV2 Microglial Cells

2020 ◽  
Vol 21 (15) ◽  
pp. 5465
Author(s):  
Jin-Seok Lee ◽  
Yoo-Jin Jeon ◽  
Ji-Yun Kang ◽  
Sam-Keun Lee ◽  
Hwa-Dong Lee ◽  
...  
Keyword(s):  
Methylene Chloride ◽  
Underlying Mechanism ◽  
Microglial Cells ◽  
Bv2 Cells ◽  
Tnf Α ◽  
Underlying Mechanisms ◽  
Bv2 Microglial Cells ◽  
Methylene Chloride Fraction

Microglial hyperactivation and neuroinflammation are known to induce neuronal death, which is one of the main causes of neurodegenerative disorders. We previously found that Aquilariae Lignum extract attenuated both neuronal excitotoxicity and neuroinflammation in vivo and in vitro. For further analysis, we extracted the methylene chloride fraction of Aquilariae Lignum to determine the bioactive compounds. In this study, we investigated the anti-neuroinflammatory effects and underlying mechanisms of the Aquilariae Lignum fraction (ALF) using lipopolysaccharide (LPS)-stimulated BV2 microglial cells. BV2 cells were pretreated with ALF (0.5, 1, and 2.5 μg/mL) before treatment with LPS (1 μg/mL). Pretreatment with ALF significantly attenuated the LPS-induced overproductions of nitric oxide (NO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and interleukin (IL)-1β. These anti-inflammatory effects were supported by ALF-mediated modulation of the nuclear factor-kappa B (NF-κB) pathway. Furthermore, ALF exerted strong anti-inflammasome effects, as shown by IL-1β-specific inhibitory activity, but not activity against tumor necrosis factor (TNF)-α, along with inhibition of caspase-1 activity and NACHT, LRR, and PYD domain-containing protein 3 (NLRP3)-related molecules. These results indicate the potent anti-neuroinflammatory activity of ALF and that its underlying mechanism may involve the regulation of NLRP3 inflammasome-derived neuroinflammation in microglial cells.

scholarly journals DJ-1 inhibits microglial activation and protects dopaminergic neurons in vitro and in vivo through interacting with microglial p65

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Zixuan Lin ◽  
Chen Chen ◽  
Dongqin Yang ◽  
Jianqing Ding ◽  
Guanghui Wang ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Nuclear Translocation ◽  
Substantia Nigra Pars Compacta ◽  
Loss Of Function ◽  
Wild Type ◽  
Wild Type Littermate ◽  
Cellular Models ◽  
Bv2 Cells

AbstractParkinson’s disease (PD), one of the most common neurodegenerative disorders, is characterized by progressive neurodegeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). DJ-1 acts essential roles in neuronal protection and anti-neuroinflammatory response, and its loss of function is tightly associated with a familial recessive form of PD. However, the molecular mechanism of DJ-1 involved in neuroinflammation is largely unclear. Here, we found that wild-type DJ-1, rather than the pathogenic L166P mutant DJ-1, directly binds to the subunit p65 of nuclear factor-κB (NF-κB) in the cytoplasm, and loss of DJ-1 promotes p65 nuclear translocation by facilitating the dissociation between p65 and NF-κB inhibitor α (IκBα). DJ-1 knockout (DJ-1−/−) mice exhibit more microglial activation compared with wild-type littermate controls, especially in response to lipopolysaccharide (LPS) treatment. In cellular models, knockdown of DJ-1 significantly upregulates the gene expression and increases the release of LPS-treated inflammatory cytokines in primary microglia and BV2 cells. Furthermore, DJ-1 deficiency in microglia significantly enhances the neuronal toxicity in response to LPS stimulus. In addition, pharmacological blockage of NF-κB nuclear translocation by SN-50 prevents microglial activation and alleviates the damage of DA neurons induced by microglial DJ-1 deficiency in vivo and in vitro. Thus, our data illustrate a novel mechanism by which DJ-1 facilitates the interaction between IκBα and p65 by binding to p65 in microglia, and thus repressing microglial activation and exhibiting the protection of DA neurons from neuroinflammation-mediated injury in PD.

Inhibition of Voltage-Gated Hv1 Alleviates LPS-Induced Neuroinflammation via Regulation of Microglial Metabolic Reprogramming

2022 ◽  
Author(s):  
Lingbin Sun ◽  
Xihua Wang ◽  
Shuyuan Guan ◽  
TAO LUO
Keyword(s):  
Cell Death ◽  
Microglial Activation ◽  
Therapeutic Potential ◽  
Aerobic Glycolysis ◽  
Neuronal Cell ◽  
Metabolic Reprogramming ◽  
Proinflammatory Response ◽  
Voltage Gated

Abstract Background Neuroinflammation plays an important role in the onset and advancement of cognitive loss and neurodegenerative disorders. The voltage-gated H channel (Hv1) has been reported to be involved in microglial activation and act as key drivers of neuroinflammation. This study aims at evaluating the mechanism of Hv1 involvement in neuroinflammation and the therapeutic potential of Hv1 inhibitor, 2-guanidinobenzimidazole (2-GBI), in a model of lipopolysaccharide (LPS)-induced neuroinflammation. Methods We investigated the influence of Hv1 inhibitor (2-GBI) on the generation of reactive oxidative species (ROS), metabolic reprogramming, and inflammatory mediators in vitro and examined the therapeutic potential of 2-GBI on microglial activation and hippocampal neuroinflammation in vivo. Novel object recognition and Y-maze were employed to assess cognitive function. Results 2-GBI reduced the LPS-induced proinflammatory response and aerobic glycolysis in microglia. HIF1α overexpression mediated aerobic glycolysis reprogramming alleviated by 2-GBI. We reported that Hv1 inhibitor exerted a protective effect on LPS-induced neuroinflammation through the ROS/HIF1α and PI3K/AKT/HIF1α pathways -mediated aerobic glycolysis. The cell death of PC12 induced by microglia-mediated neuroinflammation was reversed in a transwell co-culture system by 2-GBI. Furthermore, in vivo results suggested that 2-GBI mitigated the neuroinflammatory processes and recognition injury through regulation of microglial metabolic reprogramming. Conclusion 2-GBI protects LPS-induced neuroinflammation, neuronal cell death, and subsequently reverses the hippocampus-dependent cognitive deficits through regulation of microglial metabolic reprogramming. Taken together, these results demonstrate a key role for Hv1 in driving a pro-inflammatory microglia phenotype in neuroinflammation.

scholarly journals Rapid morphologic changes to microglial cells and upregulation of mixed microglial activation state markers induced by P2X7 receptor stimulation and increased intraocular pressure

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Keith E. Campagno ◽  
Wennan Lu ◽  
Assraa Hassan Jassim ◽  
Farraj Albalawi ◽  
Aurora Cenaj ◽  
...  
Keyword(s):  
Cell Body ◽  
P2x7 Receptor ◽  
Microglial Activation ◽  
Morphological Changes ◽  
Atp Release ◽  
Microglial Cells ◽  
Receptor Stimulation ◽  
Process Retraction

Abstract Background The identification of endogenous signals that lead to microglial activation is a key step in understanding neuroinflammatory cascades. As ATP release accompanies mechanical strain to neural tissue, and as the P2X7 receptor for ATP is expressed on microglial cells, we examined the morphological and molecular consequences of P2X7 receptor stimulation in vivo and in vitro and investigated the contribution of the P2X7 receptor in a model of increased intraocular pressure (IOP). Methods In vivo experiments involved intravitreal injections and both transient and sustained elevation of IOP. In vitro experiments were performed on isolated mouse retinal and brain microglial cells. Morphological changes were quantified in vivo using Sholl analysis. Expression of mRNA for M1- and M2-like genes was determined with qPCR. The luciferin/luciferase assay quantified retinal ATP release while fura-2 indicated cytoplasmic calcium. Microglial migration was monitored with a Boyden chamber. Results Sholl analysis of Iba1-stained cells showed retraction of microglial ramifications 1 day after injection of P2X7 receptor agonist BzATP into mouse retinae. Mean branch length of ramifications also decreased, while cell body size and expression of Nos2, Tnfa, Arg1, and Chil3 mRNA increased. BzATP induced similar morphological changes in ex vivo tissue isolated from Cx3CR1+/GFP mice, suggesting recruitment of external cells was unnecessary. Immunohistochemistry suggested primary microglial cultures expressed the P2X7 receptor, while functional expression was demonstrated with Ca2+ elevation by BzATP and block by specific antagonist A839977. BzATP induced process retraction and cell body enlargement within minutes in isolated microglial cells and increased Nos2 and Arg1. While ATP increased microglial migration, this required the P2Y12 receptor and not P2X7 receptor. Transient elevation of IOP led to microglial process retraction, cell body enlargement, and gene upregulation paralleling changes observed with BzATP injection, in addition to retinal ATP release. Pressure-dependent changes were reduced in P2X7−/− mice. Death of retinal ganglion cells accompanied increased IOP in C57Bl/6J, but not P2X7−/− mice, and neuronal loss showed some association with microglial activation. Conclusions P2X7 receptor stimulation induced rapid morphological activation of microglial cells, including process retraction and cell body enlargement, and upregulation of markers linked to both M1- and M2-type activation. Parallel responses accompanied IOP elevation, suggesting ATP release and P2X7 receptor stimulation influence the early microglial response to increased pressure.

scholarly journals Immunometabolism orchestrates training of innate immunity in atherosclerosis

2019 ◽  
Vol 115 (9) ◽  
pp. 1416-1424 ◽  
Author(s):  
Julia van Tuijl ◽  
Leo A B Joosten ◽  
Mihai G Netea ◽  
Siroon Bekkering ◽  
Niels P Riksen
Keyword(s):  
Cell Activation ◽  
Cholesterol Metabolism ◽  
Myeloid Cell ◽  
Metabolic Reprogramming ◽  
Immune Memory ◽  
Low Grade ◽  
Trained Immunity ◽  
Monocytes And Macrophages

Abstract Atherosclerosis is characterized by a persistent, low-grade inflammation of the arterial wall. Monocytes and monocyte-derived macrophages play a pivotal role in the various stages of atherosclerosis. In the past few years, metabolic reprogramming has been identified as an important controller of myeloid cell activation status. In addition, metabolic and epigenetic reprogramming are key regulatory mechanisms of trained immunity, which denotes the non-specific innate immune memory that can develop after brief stimulation of monocytes with microbial or non-microbial stimuli. In this review, we build the case that metabolic reprogramming of monocytes and macrophages, and trained immunity in particular, contribute to the pathophysiology of atherosclerosis. We discuss the specific metabolic adaptations, including changes in glycolysis, oxidative phosphorylation, and cholesterol metabolism, that have been reported in atherogenic milieus in vitro and in vivo. In addition, we will focus on the role of these metabolic pathways in the development of trained immunity.

scholarly journals The MAO Inhibitor Tranylcypromine Alters LPS- and Aβ-Mediated Neuroinflammatory Responses in Wild-type Mice and a Mouse Model of AD

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1982
Author(s):  
HyunHee Park ◽  
Kyung-Min Han ◽  
Hyongjun Jeon ◽  
Ji-Soo Lee ◽  
Hyunju Lee ◽  
...  
Keyword(s):  
Mouse Model ◽  
Proinflammatory Cytokine ◽  
Microglial Activation ◽  
Microglial Cells ◽  
Wild Type ◽  
Mao Inhibitor ◽  
Cytokine Levels ◽  
Bv2 Microglial Cells

Monoamine oxidase (MAO) has been implicated in neuroinflammation, and therapies targeting MAO are of interest for neurodegenerative diseases. The small-molecule drug tranylcypromine, an inhibitor of MAO, is currently used as an antidepressant and in the treatment of cancer. However, whether tranylcypromine can regulate LPS- and/or Aβ-induced neuroinflammation in the brain has not been well-studied. In the present study, we found that tranylcypromine selectively altered LPS-induced proinflammatory cytokine levels in BV2 microglial cells but not primary astrocytes. In addition, tranylcypromine modulated LPS-mediated TLR4/ERK/STAT3 signaling to alter neuroinflammatory responses in BV2 microglial cells. Importantly, tranylcypromine significantly reduced microglial activation as well as proinflammatory cytokine levels in LPS-injected wild-type mice. Moreover, injection of tranylcypromine in 5xFAD mice (a mouse model of AD) significantly decreased microglial activation but had smaller effects on astrocyte activation. Taken together, our results suggest that tranylcypromine can suppress LPS- and Aβ-induced neuroinflammatory responses in vitro and in vivo.

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