BRD4 inhibition alleviates mechanical stress-induced TMJ OA-like pathological changes and attenuates TREM1-mediated inflammatory response

AbstractThe aim of this paper was to investigate the protective effects of bromodomain containing 4 (BRD4) inhibition on the temporomandibular joint osteoarthritis (TMJ OA) induced by compressive mechanical stress and to explore the underlying mechanism. In vivo, a rat model of TMJ compressive loading device was used and BRD4 inhibitor was injected into the TMJ region. HE staining and micro-CT analysis were used for histological and radiographic assessment. Immunohistochemistry and qPCR were performed to detect inflammatory cytokines expressions. High-throughput ChIP-sequencing screening was performed to compare the BRD4 and H3K27ac binding patterns between condylar cartilage from control and mechanical force groups. In vitro, the mandibular condylar chondrocytes were treated with IL-1β. Small Interference RNA (siRNA) infection was used to silencing BRD4 or TREM1. qPCR was performed to detect inflammatory cytokines expressions. Our study showed that BRD4 inhibition can alleviate the thinning of condylar cartilage and subchondral bone resorption, as well as decrease the inflammatory factors expression both in vivo and in vitro. ChIP-seq analysis showed that BRD4 was more enriched in the promoter region of genes related to the stress and inflammatory pathways under mechanical stress in vivo. Trem1, a pro-inflammatory gene, was screened out from the overlapped BRD4 and H3K27ac increased binding sites, and Trem1 mRNA was found to be regulated by BRD4 inhibition both in vivo and in vitro. TREM1 inhibition reduced the expression of inflammatory factors induced by IL-1β in vitro. In summary, we concluded that BRD4 inhibition can protect TMJ OA-like pathological changes induced by mechanical stress and attenuate TREM1-mediated inflammatory response.

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RhTrx-1 ameliorates miroglial neuroinflammation after cerebral ischemic stroke

10.21203/rs.3.rs-18172/v1 ◽

2020 ◽

Author(s):

Yang Jiao ◽

Jianjian Wang ◽

Huixue Zhang ◽

Yuze Cao ◽

Yang Qu ◽

...

Keyword(s):

Ischemic Stroke ◽

Inflammatory Response ◽

Inflammatory Responses ◽

Inflammatory Factors ◽

Experimental Stroke ◽

Inflammasome Activation ◽

Cerebral Ischemic

Abstract Background Microglia are rapidly activated after ischemic stroke and participate in the occurrence of neuroinflammation, which exacerbates the injury of ischemic stroke. Receptor Interacting Serine Threonine Kinase 1 (RIPK1) is thought to be involved in the development of inflammatory responses, but its role in ischemic microglia remains unclear. Here, we applied recombinant human thioredoxin-1 (rhTrx-1), a potential neuroprotective agent, to explore the role of rhTrx-1 in inhibiting RIPK1-mediated neuroinflammatory responses in microglia. Method Middle cerebral artery occlusion (MCAO) and Oxygen and glucose deprivation (OGD) were conducted for in vivo and in vitro experimental stroke models. The expression of RIPK1 in microglia after ischemia was examined. The inflammatory response of microglia was analyzed after treatment with rhTrx-1 and Necrostatin-1 (Nec-1, inhibitors of RIPK1), and the mechanisms were explored. In addition, the effects of rhTrx-1 on neurobehavioral deficits and cerebral infarct volume were examined. Results RIPK1 expression was detected in microglia after ischemia. Molecular docking results showed that rhTrx-1 could directly bind to RIPK1. In vitro experiments found that rhTrx-1 reduced necroptosis, mitochondrial membrane potential damage, Reactive oxygen species (ROS) accumulation and NLR Family, pyrin domain-containing 3 protein (NLRP3) inflammasome activation by inhibiting RIPK-1 expression, and regulated microglial M1/M2 phenotypic changes, thereby reducing the release of inflammatory factors. Consistently, in vivo experiments found that rhTrx-1 treatment attenuated cerebral ischemic injury by inhibiting the inflammatory response. Conclusion Our study demonstrates the role of RIPK1 in microglia-arranged neuroinflammation after cerebral ischemia. Administration of rhTrx-1 provides neuroprotection in ischemic stroke-induced microglial neuroinflammation by inhibiting RIPK1 expression.

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MicroRNA-181a-5p regulates inflammatory response of macrophages in sepsis

Open Medicine ◽

10.1515/med-2019-0106 ◽

2019 ◽

Vol 14 (1) ◽

pp. 899-908 ◽

Cited By ~ 4

Author(s):

Zheng Huang ◽

Hang Xu

Keyword(s):

Inflammatory Response ◽

Inflammatory Cytokines ◽

Sirtuin 1 ◽

Raw 264.7 Cells ◽

Inflammatory Factors ◽

Raw 264.7 ◽

Raw264.7 Macrophages ◽

Pathway Activation

AbstractThe aim of this study was to evaluate the role of miR-181a-5p in sepsis, and to further explore the molecular mechanism. RAW 264.7 cells were stimulated with 1 μg/ml LPS for 4 hours. Firstly, qRT-PCR and ELISA was adopted to evaluate the expression of miR-181a-5p and p ro-inflammatory cytokines in RAW 264.7 macrophages a fter LPS stimulation. Results showed that pro-inflammatory cytokines and miR-181a-5p were significantly increased after LPS treatment. Then, we identified that sirtuin-1 (SIRT1) was a direct target of miR-181a-5p and it was down-regulated in LPS treated RAW264.7 macrophages. Furthermore, the data suggested that the miR-181a-5p inhibitor significantly inhibited LPS enhanced inflammatory cytokines expression and NF-κB pathway activation, and these changes were eliminated by SIRT1 silencing. Moreover, the role of the miR-181a-5p inhibitor on sepsis was studied in vivo. We found that the miR-181a-5p inhibitor significantly decreased the secretion of inflammatory factors, and the levels of creatine (Cr), blood urea nitrogen (BUN), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a serum for mice with sepsis. However, all the effects were reversed by SIRT1-siRNA. In summary, these results indicated that miR-181a-5p was involved in sepsis through regulating the inflammatory response by targeting SIRT1, suggesting that miR-181a-5p may be a potential target for the treatment of sepsis.

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The Regulatory Role of High-Mobility Group Protein 1 in Sepsis-Related Immunity

Frontiers in Immunology ◽

10.3389/fimmu.2020.601815 ◽

2021 ◽

Vol 11 ◽

Author(s):

Li Li ◽

Yuan-Qiang Lu

Keyword(s):

Inflammatory Response ◽

Treatment Strategies ◽

High Mobility ◽

Suppressor Cells ◽

High Mobility Group ◽

Inflammatory Factors ◽

High Mobility Group Protein ◽

Immune Disorder

High-mobility group box 1 (HMGB1), a prototypical damage-associated molecular pattern (DAMP) molecule, participates in multiple processes of various inflammatory diseases through binding to its corresponding receptors. In the early phase, sepsis is mainly characterized as a multi-bacterial-induced complex, excessive inflammatory response accompanied by the release of pro-inflammatory mediators, which subsequently develops into immune paralysis. A growing number of in vivo and in vitro investigations reveal that HMGB1 plays a pivotal role in the processes of inflammatory response and immunosuppression of sepsis. Therefore, HMGB1 exerts an indispensable role in the immune disorder and life-threatening inflammatory syndrome of sepsis. HMGB1 mainly mediate the release of inflammatory factors via acting on immune cells, pyroptosis pathways and phosphorylating nuclear factor-κB. Moreover HMGB1 is also associated with the process of sepsis-related immunosuppression. Neutrophil dysfunction mediated by HMGB1 is also an aspect of the immunosuppressive mechanism of sepsis. Myeloid-derived suppressor cells (MDSCs), which are also one of the important cells that play an immunosuppressive effect in sepsis, may connect with HMGB1. Thence, further understanding of HMGB1-associated pathogenesis of sepsis may assist in development of promising treatment strategies. This review mainly discusses current perspectives on the roles of HMGB1 in sepsis-related inflammation and immunosuppressive process and its related internal regulatory mechanisms.

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Exosomes from MiR-30d-5p-ADSCs Reverse Acute Ischemic Stroke-Induced, Autophagy-Mediated Brain Injury by Promoting M2 Microglial/Macrophage Polarization

Cellular Physiology and Biochemistry ◽

10.1159/000490078 ◽

2018 ◽

Vol 47 (2) ◽

pp. 864-878 ◽

Cited By ~ 60

Author(s):

Mei Jiang ◽

Hairong Wang ◽

Mingming Jin ◽

Xuelian Yang ◽

Haifeng Ji ◽

...

Keyword(s):

Ischemic Stroke ◽

Inflammatory Response ◽

Acute Ischemic Stroke ◽

Inflammatory Cytokines ◽

Macrophage Polarization ◽

Cerebral Injury ◽

Inflammatory Factors ◽

Protective Mechanism ◽

Microglial Polarization

Background/Aims: Recent studies have indicated that exosomes secreted from adipose-derived stem cells (ADSCs) have important effects in the treatment of ischemic injury. However, the treatment mechanism is unclear. This study aimed to investigate whether ADSC-derived exosomes enriched with microRNA (miR)-30d-5p have a protective effect on acute ischemic stroke (AIS). Methods: In the current study, inflammatory factors and miR-30d-5p expression were assessed in 70 subjects with AIS and 35 healthy controls. Exosomes were characterized by transmission electron microscopy and further examined using nanoparticle tracking analyses. A rat model of AIS and an in vitro model of oxygen- and glucose-deprived (OGD) primary microglia were established to study the protective mechanism of exosomes from miR-30d-5p-overexpressing ADSCs in ischemia-induced nerve injury. Results: The results showed that following AIS, the expression of inflammatory cytokines increased, while the anti-inflammatory cytokines IL-4, IL-10, and miR-30d-5p decreased both in patients and in animal models. Moreover, in vitro studies demonstrated that suppression of autophagy significantly reduced the OGD-induced inflammatory response. In addition, exosome treatment was more effective in suppressing the inflammatory response by reversing OGD-induced and autophagy-mediated microglial polarization to M1. Furthermore, in vivo studies showed that exosomes derived from ADSCs significantly decreased the cerebral injury area of infarction by suppressing autophagy and promoting M2 microglia/macrophage polarization. Conclusions: Our results suggest that miR-30d-5p-enhanced ADSC-derived exosomes prevent cerebral injury by inhibiting autophagy-mediated microglial polarization to M1.

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Stevioside Activates AMPK to Suppress Inflammation in Macrophages and Protects Mice from LPS-Induced Lethal Shock

Molecules ◽

10.3390/molecules26040858 ◽

2021 ◽

Vol 26 (4) ◽

pp. 858

Author(s):

Fuyao Wei ◽

Hong Zhu ◽

Na Li ◽

Chunlei Yu ◽

Zhenbo Song ◽

...

Keyword(s):

Inflammatory Cytokines ◽

Mononuclear Cells ◽

Inflammatory Responses ◽

Raw 264.7 Cells ◽

Inflammatory Factors ◽

Enhanced Production ◽

Lethal Shock ◽

Anti Inflammatory

Stevioside, a diterpenoid glycoside, is widely used as a natural sweetener; meanwhile, it has been proven to possess various pharmacological properties as well. However, until now there were no comprehensive evaluations focused on the anti-inflammatory activity of stevioside. Thus, the anti-inflammatory activities of stevioside, both in macrophages (RAW 264.7 cells, THP-1 cells, and mouse peritoneal macrophages) and in mice, were extensively investigated for the potential application of stevioside as a novel anti-inflammatory agent. The results showed that stevioside was capable of down-regulating lipopolysaccharide (LPS)-induced expression and production of pro-inflammatory cytokines and mediators in macrophages from different sources, such as IL-6, TNF-α, IL-1β, iNOS/NO, COX2, and HMGB1, whereas it up-regulated the anti-inflammatory cytokines IL-10 and TGF-β1. Further investigation showed that stevioside could activate the AMPK -mediated inhibition of IRF5 and NF-κB pathways. Similarly, in mice with LPS-induced lethal shock, stevioside inhibited release of pro-inflammatory factors, enhanced production of IL-10, and increased the survival rate of mice. More importantly, stevioside was also shown to activate AMPK in the periphery blood mononuclear cells of mice. Together, these results indicated that stevioside could significantly attenuate LPS-induced inflammatory responses both in vitro and in vivo through regulating several signaling pathways. These findings further strengthened the evidence that stevioside may be developed into a therapeutic agent against inflammatory diseases.

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Regulation of IFN-Is by MEF2D Promotes Inflammatory Homeostasis in Microglia

10.21203/rs.3.rs-225160/v1 ◽

2021 ◽

Author(s):

Fangfang Lu ◽

Ronglin Wang ◽

Tiejian Nie ◽

Fei Gao ◽

Shaosong Yang ◽

...

Keyword(s):

Inflammatory Response ◽

Signaling Pathway ◽

Response Regulator ◽

Expression Patterns ◽

Inflammatory Factors ◽

Type I ◽

Immune Balance ◽

Bv2 Cells

Abstract Background Microglia play an essential role in the host defense of central nervous system. Transcription factor MEF2D is known to participate in stress regulation of various cells and is tightly triggered in microglia in vivo and in vitro. MEF2D is shown to bind at the promoter region of several cytokine genes in immune cells, and directly regulates inflammatory response, suggesting that MEF2D may act as a key stimulus response regulator of microglia and is involved in the regulation of brain micro-homeostasis. In order to uncover the molecular mechanism of MEF2D in inflammatory system, in the present study, we investigated the global effect of MEF2D in activated microglia, and explored its potential regulatory network. Methods Experiments of recombinant lentivirus vector of shRNA and specific MEF2D over-expression were performed in BV2 cells. Transcriptome sequencing and the global gene expression patterns were analyzed in lipopolysaccharide-stimulated shMEF2D BV2 cells. The pro- and anti-inflammatory factors were assessed by western blot, qPCR or ELISA, and microglia activity by phagocytosis and morphologic analysis. The directly binding of MEF2D to the promoter regions of IRF7 were tested by ChIP-qPCR and PCR. The ISGs were tested by qPCR. Results MEF2D was shown to actively participate in the inflammatory response of BV2 microglial cells. RNAi induced stable silence of MEF2D broke the immune balance of microglia, in two ways: (1) promoted the expression of pro-inflammatory factors, such as NLRP3, IL-1β, iNOS; and (2) markedly inhibited the type-I interferon signaling pathway by directly modulating the transcription of IRF7. On the contrary, overexpression of MEF2D significantly reduced the expression of NLRP3 and iNOS under LPS stimulation, and alleviated the level of immune stress in microglia. Conclusions These findings demonstrate that MEF2D plays an important role in the regulation of inflammatory homeostasis partly through transcriptional regulation of the IFN-Is response signaling pathway.

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Role of cholinergic anti-inflammatory pathway in protecting sepsis-induced acute lung injury through regulation of the dendritic cells

10.21203/rs.3.rs-310671/v1 ◽

2021 ◽

Author(s):

Ruiting Li ◽

Xuemei Hu ◽

Huibin Chen ◽

Yin Yuan ◽

Huiling Guo ◽

...

Keyword(s):

Immune Response ◽

Dendritic Cells ◽

Acute Lung Injury ◽

Lung Injury ◽

Inflammatory Response ◽

Inflammatory Cytokines ◽

Mice Model ◽

Pro Inflammatory Cytokines

Abstract Background The cholinergic anti-inflammatory pathway (CAP) connects the immune response system and the nervous system via the vagus nerve. The key regulatory receptor is the α7-subtype of the nicotinic acetylcholine receptor (α7nAChR), which is localized on the surface of the cells of immune system. CAP has been proved to be effective in suppressing the inflammation responses in acute lung injury (ALI). Dendritic cells (DCs), the important antigen-presenting cells (APCs), also express the α7nAChR. They not only play an important role in immune response priming but also in participating in the pathological process of ALI. Past studies have indicated that reducing the quantity of mature conventional DCs (cDCs) and inhibiting the maturation of pulmonary DCs may prove effective for the treatment of ALI. However, the effects of CAP on maturation, function and quantity of DCs and cDCs in ALI remain unclear. Objective It was hypothesized that the activation of CAP may inhibit the inflammatory response of ALI by regulating maturation, phenotype, and quantity of DCs and cDCs. This can be considered as an important intervention strategy for treating ALI. Methods GTS-21 (GTS-21 dihydrochloride), an α7nAchR agonist was administered in sepsis-induced ALI mice model and LPS-primed bone marrow-derived dendritic cells (BMDCs). The effects of GTS-21 were observed with respect to maturation, phenotype, and quantity of DCs, cDCs, and cDCs2 (type 2 cDCs), and the release of DC-related pro-inflammatory cytokines (such as IL-6, TNF-α, IL-18 IL-1β, IL-12p40, and HMGB1) in vivo and in vitro conditions. Results The results of the present study revealed that, GTS-21 treatment regulated the maturation of DCs and the production of DC-related pro-inflammatory cytokines in vitro and in sepsis-induced ALI mice model, it reduced the quantity of CD11c+MHCII+ cDCs and CD11c+CD11b+ cDCs2 in vivo experiment. Conclusions The activation of CAP contributes to the reduction in the inflammatory response in ALI by regulating maturation, phenotype, and quantity of DCs, cDCs, and cDCs2.

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Bullatine a Exerted Anti-Inflammatory Effects by Inhibiting JNK/ROS/NF-κB Pathway and Attenuates Systemic Inflammatory Response in LPS-Challenged Mice

10.21203/rs.3.rs-710437/v1 ◽

2021 ◽

Author(s):

Shuhan Liu ◽

Meichen Yan ◽

Yajin Liao ◽

Yong Cheng

Keyword(s):

Inflammatory Response ◽

Inflammatory Cytokines ◽

Nuclear Translocation ◽

Ros Generation ◽

Mrna Levels ◽

Iκb Kinase ◽

Inflammatory Mechanism ◽

Anti Inflammatory

Abstract Background: The genus Aconitum has rich pharmacological characteristics. Aconiti brachypodi Radix (Xue-shang-yi-zhi-hao) is a dried root of aconitum, which is considered to be analgesic and anti-inflammatory in modern medical and pharmaceutical clinical studies. Bullatine A (BA), a major active ingredient of this plant, has been reported for its significant anti-analgesic effect in previous studies. However, the role of BA in inflammation is unknown. In the current study, we aimed to explore the effect of BA on lipopolysaccharide (LPS)-induced inflammatory response both in vitro and in vivo and its potential anti-inflammatory mechanism.Materials and Methods: The anti-inflammatory effect of BA was evaluated in two different types of LPS-induced macrophages, including BV-2 microglial cells and immortalized murine bone marrow-derived macrophages (iBMDMs), and in acute inflammation mouse models induced by LPS. Immunofluorescence, flow cytometry, quantitative RT-PCR, western blot and Hematoxylin-Eosin staining were used to determine the anti-inflammatory properties of BA.Results: The results showed that BA significantly reduced the mRNA levels of several pro-inflammatory cytokines induced by LPS both in BV-2 cells and iBMDMs. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in response to LPS were also decreased by BA. Further investigations indicated BA significantly blocked the phosphorylation of IκB kinase, degradation of the inhibitor IκBa and the nuclear translocation of nuclear factor-κB (NF-κB) p65. BA also reduced c-Jun N-terminal kinases (JNK) phosphorylation and ROS generation in iBMDMs activated with LPS, but had no effect on other mitogen-activated protein kinases (MAPKs) family proteins such as extracellular signal-regulated kinase (ERK) or p38. Furthermore, BA treatment alleviate liver and lung tissue damage, reduce inflammatory cell infiltration, and inhibit the expression of inflammatory cytokines in LPS-challenged mice.Conclusions: This study illustrated that BA has obvious anti-inflammatory effects both in vitro and in vivo, and its underlying anti-inflammatory mechanism may be via inactivating JNK/ROS/NF-κB pathway. Therefore, BA may have a certain therapeutic potential for inflammatory-related diseases.

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NOD1/RIP2 signalling enhances the microglia-driven inflammatory response and undergoes crosstalk with inflammatory cytokines to exacerbate brain damage following intracerebral haemorrhage in mice

Journal of Neuroinflammation ◽

10.1186/s12974-020-02015-9 ◽

2020 ◽

Vol 17 (1) ◽

Author(s):

Miao Wang ◽

Xinchun Ye ◽

Jinxia Hu ◽

Qiuchen Zhao ◽

Bingchen Lv ◽

...

Keyword(s):

Inflammatory Response ◽

Brain Damage ◽

Microglial Activation ◽

Inflammatory Factors ◽

Primary Microglia ◽

Tnf Α ◽

Factor Α ◽

Necrosis Factor

Abstract Background Secondary brain damage caused by the innate immune response and subsequent proinflammatory factor production is a major factor contributing to the high mortality of intracerebral haemorrhage (ICH). Nucleotide-binding oligomerization domain 1 (NOD1)/receptor-interacting protein 2 (RIP2) signalling has been reported to participate in the innate immune response and inflammatory response. Therefore, we investigated the role of NOD1/RIP2 signalling in mice with collagenase-induced ICH and in cultured primary microglia challenged with hemin. Methods Adult male C57BL/6 mice were subjected to collagenase for induction of ICH model in vivo. Cultured primary microglia and BV2 microglial cells (microglial cell line) challenged with hemin aimed to simulate the ICH model in vitro. We first defined the expression of NOD1 and RIP2 in vivo and in vitro using an ICH model by western blotting. The effect of NOD1/RIP2 signalling on ICH-induced brain injury volume, neurological deficits, brain oedema, and microglial activation were assessed following intraventricular injection of either ML130 (a NOD1 inhibitor) or GSK583 (a RIP2 inhibitor). In addition, levels of JNK/P38 MAPK, IκBα, and inflammatory factors, including tumour necrosis factor-α (TNF-α), interleukin (IL)-1β, and inducible nitric oxide synthase (iNOS) expression, were analysed in ICH-challenged brain and hemin-exposed cultured primary microglia by western blotting. Finally, we investigated whether the inflammatory factors could undergo crosstalk with NOD1 and RIP2. Results The levels of NOD1 and its adaptor RIP2 were significantly elevated in the brains of mice in response to ICH and in cultured primary microglia, BV2 cells challenged with hemin. Administration of either a NOD1 or RIP2 inhibitor in mice with ICH prevented microglial activation and neuroinflammation, followed by alleviation of ICH-induced brain damage. Interestingly, the inflammatory factors interleukin (IL)-1β and tumour necrosis factor-α (TNF-α), which were enhanced by NOD1/RIP2 signalling, were found to contribute to the NOD1 and RIP2 upregulation in our study. Conclusion NOD1/RIP2 signalling played an important role in the regulation of the inflammatory response during ICH. In addition, a vicious feedback cycle was observed between NOD1/RIP2 and IL-1β/TNF-α, which could to some extent result in sustained brain damage during ICH. Hence, our study highlights NOD1/RIP2 signalling as a potential therapeutic target to protect the brain against secondary brain damage during ICH.

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