Colony stimulating factor 1 receptor inhibition eliminates microglia and attenuates brain injury after intracerebral hemorrhage.
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ABSTRACT:
SUBMITTER: Li M
PROVIDER: S-EPMC5482387 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Intracerebral hemorrhage (ICH) is a devastating disease without effective treatment. After ICH, the immediate infiltration of leukocytes and activation of microglia are accompanied by a rapid up-regulation of the 18-kDa translocator protein (TSPO). TSPO ligands have shown anti-inflammatory and neuroprotective properties in models of CNS injury. In this study, we determined the impact of a TSPO ligand, etifoxine, on brain injury and inflammation in 2 mouse models of ICH. TSPO was up-regulated in Iba1+ cells from brains of patients with ICH and in CD11b+CD45int cells from mice subjected to collagenase-induced ICH. Etifoxine significantly reduced neurodeficits and perihematomal brain edema after ICH induction by injection of either autologous blood or collagenase. In collagenase-induced ICH mice, the protection of etifoxine was associated with reduced leukocyte infiltration into the brain and microglial production of IL-6 and TNF-α. Etifoxine improved blood-brain barrier integrity and diminished cell death. Notably, the protective effect of etifoxine was abolished in mice depleted of microglia by using a colony-stimulating factor 1 receptor inhibitor. These results indicate that the TSPO ligand etifoxine attenuates brain injury and inflammation after ICH. TSPO may be a viable therapeutic target that requires further investigations in ICH.-Li, M., Ren, H., Sheth, K. N., Shi, F.-D., Liu, Q. A TSPO ligand attenuates brain injury after intracerebral hemorrhage.
| S-EPMC5503714 | biostudies-literature
Project description:Hematoma-induced neuroinflammation is the cause of poor prognosis in intracerebral hemorrhage (ICH); therefore, promoting blood clearance and blocking overactivated inflammation are rational approaches for ICH treatment. β-site amyloid precursor protein (APP) lyase-1 (BACE1) is a key molecule regulating the microglial phenotype transition in neurodegenerative diseases. Therefore, the aim of this study was to investigate the role of BACE1 in microglial phagocytosis and inflammatory features in ICH. Here, we demonstrated the unique advantages of targeting BACE1 in microglia using an autologous blood model and primary microglia hemoglobin stimulation. When BACE1 was inhibited early in ICH, fewer residual hematomas remained, consistent with an increase in genetic features that favor phagocytosis and anti-inflammation. In addition, inhibition of BACE1 enhanced the secretion of anti-inflammatory cytokines and substantially reduced the expression of proinflammatory genes, which was regulated by signal transduction and phosphorylation of activator of transcription 3 (STAT3). Further pharmacological inhibition of STAT3 phosphorylation effectively blocked the proinflammatory and weak phagocytic phenotype of microglia due to BACE1 induction. In summary, BACE1 is the critical molecule regulating the inflammatory and phagocytic phenotypes of microglia after ICH, and targeted inhibition of the BACE1/STAT3 pathway is an important strategy for the future treatment of ICH-induced neurological injury.
| S-EPMC10457076 | biostudies-literature
Project description:Protein posttranslational modifications (PTMs) has been shown to regulate biological processes of human diseases via expanding the genetic code and for regulating cellular pathophysiology, however, the system-wide changes at the PTMs levels in ICH brain remains little known. Given that succinylation is one of the important PTMs in regulating many biological processes. Therefore, in this study, we used a high-resolution mass spectrometry-based, quantitative succinyllysine proteomics approach to firstly investigated the ICH-associated brain protein succinyllysine modifications. We totally identified the concentration of approximately 6000 succinylation events and quantified approximately 3500 sites. Among them, 25 succinyllysine sites on 23 proteins were increased, while 13 succinyllysine sites on 12 proteins were downregulated after ICH. Additionally, the subcellular localization analysis of these significantly changed succinylproteins showed that 58.3% hyposuccinylated proteins were located in the mitochondria, while the percentage of succinylproteins located in mitochondria was decreased to about 35% in ICH brains with concomitant increasing in the percentage of cytoplasm to 30.4%. Further bioinformatic analysis showed that the succinylated proteins were mostly located in mitochondria and synapse-related subcellular spaces, and participate in many pathophysiological processes, such as metabolism, cytoskeleton organization, synapse working and ferroptosis, etc.. Moreover, we performed a combination analysis of our succinylproteomics data with previously published transcriptome data and found that most of the differentially succinylated proteins were distributed into neurons, endothelial cells and astrocytes. In conclusion, our analyses uncover a number of succinylation-affected processes and pathways in ICH brains and provide new insights for understanding ICH pathophysiological processes.
2021-10-29 | PXD025621 | Pride
Project description:Microglial activation and subsequent inflammatory responses are critical processes in aggravating secondary brain injury after intracerebral hemorrhage (ICH). Pterostilbene (3', 5'-dimethoxy-resveratrol) features antioxidant and anti-inflammation properties and has been proven neuroprotective. In this study, we aimed to explore whether Pterostilbene could attenuate neuroinflammation after experimental ICH, as well as underlying molecular mechanisms. Here, a collagenase-induced ICH in mice was followed by intraperitoneal injection of Pterostilbene (10 mg/kg) or vehicle once daily. PTE-treated mice performed significantly better than vehicle-treated controls in the neurological behavior test after ICH. Furthermore, our results showed that Pterostilbene reduced lesion volume and neural apoptosis, and alleviated blood-brain barrier (BBB) damage and brain edema. RNA sequencing and subsequent experiments showed that ICH-induced neuroinflammation and microglial proinflammatory activities were markedly suppressed by Pterostilbene treatment. With regard to the mechanisms, we identified that the anti-inflammatory effects of Pterostilbene relied on remodeling mitochondrial dynamics in microglia. Concretely, Pterostilbene reversed the downregulation of OPA1, promoted mitochondrial fusion, restored normal mitochondrial morphology, and reduced mitochondrial fragmentation and superoxide in microglia after OxyHb treatment. Moreover, conditionally deleting microglial OPA1 in mice largely countered the effects of Pterostilbene on alleviating microglial inflammation, BBB damage, brain edema and neurological impairment following ICH. In summary, we provided the first evidence that Pterostilbene is a promising agent for alleviating neuroinflammation and brain injury after ICH in mice, and uncovered a novel regulatory relationship between Pterostilbene and OPA1-mediated mitochondrial fusion.
| S-EPMC10442819 | biostudies-literature
Project description:Replenishment of NAD+ has been shown to protect against brain disorders such as amyotrophic lateral sclerosis and ischemic stroke. However, whether this intervention has therapeutic effects in intracerebral hemorrhage (ICH) is unknown. In this study, we sought to determine the potential therapeutic value of replenishment of NAD+ in ICH. In a collagenase-induced ICH (cICH) mouse model, nicotinamide mononucleotide (NMN), a key intermediate of nicotinamide adenine dinucleotide (NAD+) biosynthesis, was administrated at 30 minutes post cICH from tail vein to replenish NAD+. NMN treatment did not decrease hematoma volume and hemoglobin content. However, NMN treatment significantly reduced brain edema, brain cell death, oxidative stress, neuroinflammation, intercellular adhesion molecule-1 expression, microglia activation and neutrophil infiltration in brain hemorrhagic area. Mechanistically, NMN enhanced the expression of two cytoprotective proteins: heme oxygenase 1 (HO-1) and nuclear factor-like 2 (Nrf2). Moreover, NMN increased the nuclear translocation of Nrf2 for its activation. Finally, a prolonged NMN treatment for 7 days markedly promoted the recovery of body weight and neurological function. These results demonstrate that NMN treats brain injury in ICH by suppressing neuroinflammation/oxidative stress. The activation of Nrf2/HO-1 signaling pathway may contribute to the neuroprotection of NMN in ICH.
| S-EPMC5429727 | biostudies-literature
Project description:BackgroundWhite matter injury (WMI) is a major neuropathological event associated with intracerebral hemorrhage (ICH). P2X purinoreceptor 4 (P2X4R) is a member of the P2X purine receptor family, which plays a crucial role in regulating WMI and neuroinflammation in central nervous system (CNS) diseases. Our study investigated the role of P2X4R in the WMI and the inflammatory response in mice, as well as the possible mechanism of action after ICH.MethodsICH was induced in mice via collagenase injection. Mice were treated with 5-BDBD and ANA-12 to inhibit P2X4R and tropomyosin-related kinase receptor B (TrkB), respectively. Immunostaining and quantitative polymerase chain reaction (qPCR) were performed to detect microglial phenotypes after the inhibition of P2X4R. Western blots (WB) and immunostaining were used to examine WMI and the underlying molecular mechanisms. Cylinder, corner turn, wire hanging, and forelimb placement tests were conducted to evaluate neurobehavioral function.ResultsAfter ICH, the protein levels of P2X4R were upregulated, especially on day 7 after ICH, and were mainly located in the microglia. The inhibition of P2X4R via 5-BDBD promoted neurofunctional recovery after ICH as well as the transformation of the pro-inflammatory microglia induced by ICH into an anti-inflammatory phenotype, and attenuated ICH-induced WMI. Furthermore, we found that TrkB blockage can reverse the protective effects of WMI as well as neuroprotection after 5-BDBD treatment. This result indicates that P2X4R plays a crucial role in regulating WMI and neuroinflammation and that P2X4R inhibition may benefit patients with ICH.ConclusionsOur results demonstrated that P2X4R contributes to WMI by polarizing microglia into a pro-inflammatory phenotype after ICH. Furthermore, the inhibition of P2X4R promoted pro-inflammatory microglia polarization into an anti-inflammatory phenotype, enhanced brain-derived neurotrophic factor (BDNF) production, and through the BDNF/TrkB pathway, attenuated WMI and improved neurological function. Therefore, the regulation of P2X4R activation may be beneficial for the reducing of ICH-induced brain injury.
| S-EPMC8383380 | biostudies-literature
Project description:Protein posttranslational modifications (PTMs) regulate the biological processes of human diseases by genetic code expansion and cellular pathophysiology regulation; however, system-wide changes in PTM levels in the intracerebral hemorrhage (ICH) brain remain poorly understood. Succinylation refers to a major PTM during the regulation of multiple biological processes. In this study, according to the methods of quantitative succinyllysine proteomics based on high-resolution mass spectrometry, we investigated ICH-associated brain protein succinyllysine modifications and obtained 3,680 succinylated sites and quantified around 3,530 sites. Among them, 25 succinyllysine sites on 23 proteins were upregulated (hypersuccinylated), whereas 13 succinyllysine sites on 12 proteins were downregulated (hyposuccinylated) following ICH. The cell component enrichment analysis of these succinylproteins with significant changes showed that 58.3% of the hyposuccinylated proteins were observed in the mitochondria, while the hyper-succinylproteins located in mitochondria decreased in the percentage to about 35% in ICH brains with a concomitant increase in the percentage of cytoplasm to 30.4%. Further bioinformatic analysis showed that the succinylproteins were mostly mitochondria and synapse-related subcellular located and involved in many pathophysiological processes, like metabolism, synapse working, and ferroptosis. Moreover, the integrative analysis of our succinylproteomics data and previously published transcriptome data showed that the mRNAs matched by most differentially succinylated proteins were especially highly expressed in neurons, endothelial cells, and astrocytes. Our study uncovers some succinylation-affected processes and pathways in response to ICH brains and gives us novel insights into understanding pathophysiological processes of brain injury caused by ICH.
| S-EPMC8592435 | biostudies-literature
Project description:NLRP6 inflammasome, one of the important intracellular innate immune sensors, has been shown to regulate immune responses. However, its roles in the intracerebral hemorrhage (ICH) are completely not clear. In the present study, we investigated the expression profile and biological roles of NLRP6 inflammasome in perihematomal brain tissues of mice subjected to ICH. In this study, we investigated the expression profile of NLRP6 inflammasome in the perihematomal brain tissues and explored the biological role of NLRP6 inflammasome upon acute brain injury in mice subjected to ICH. Increased expression of NLRP6 inflammasome was found in perihematomal brain tissues ranging from 6 h to 3 days, with a peak level at 1 day after ICH. Immunohistochemistry staining also showed that NLRP6 inflammasome was significantly increased in the perihematomal brain tissues at 1 day after ICH. Moreover, immunofluorescence staining showed that NLRP6 inflammasome was mainly colocalized in glial fibrillary acidic protein (GFAP)-positive astrocytes, while with little colocalized expression in NeuN-positive neurons and without expression in CD11b-positive microglia and CD31-positive endothelial cell in the perihematomal brain tissue of mice after ICH. Furthermore, NLRP6-/- ICH mice exhibited significantly higher brain water contents (BMCs), proinflammatory cytokines, NF-κB activity and neurological deficit scores when compared with the wild type (WT) ICH mice. In addition, we found that Toll-like receptor 4 (TLR4)-/- mice, as well as the TAK242 treated mice, had markedly lower expression of NLRP6 inflammasome expression in the perihematomal brain tissue at 1 day after ICH. Our data suggest that the upregulated NLRP6 inflammasome in perihematomal brain tissues attenuates ICH-induced brain injury.
| S-EPMC5527702 | biostudies-literature
Project description:BackgroundIntracerebral hemorrhage (ICH) is a severe cerebrovascular disease with high morbidity and mortality rates. Oxidative stress and inflammation are important pathological mechanisms of secondary brain injury (SBI) after ICH. Brain and muscle Arnt-like protein 1 (BMAL1), which forms the core component of the circadian clock, was previously shown to be involved in many diseases and to participate in oxidative stress and inflammatory responses. However, the role of BMAL1 in SBI following ICH is unknown. In addition, treatments targeting miR-155 and its downstream signaling pathway may exert a beneficial effect on SBI after ICH, while miR-155 may regulate Bmal1 mRNA stability and translation. Nevertheless, researchers have not clearly determined whetheantagomir-155 upregulates BMAL1 expression and subsequently attenuates ICH-induced brain injury in rats.MethodsAfter establishing an ICH rat model by injecting autologous blood, the time course of changes in levels of the BMAL1 protein after ICH was analyzed. Subsequently, this study was designed to investigate the potential role and mechanisms of BMAL1 in SBI following ICH using lentiviral overexpression and antagomir-155 treatments.ResultsBMAL1 protein levels were significantly decreased in the ICH group compared to the sham group. Genetic overexpression of BMAL1 alleviated oxidative stress, inflammation, brain edema, blood-brain barrier injury, neuronal death, and neurological dysfunction induced by ICH. On the other hand, we observed that inhibiting miRNA-155 using antagomir-155 promoted the expression of BMAL1 and further activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway to attenuate brain injury after ICH.ConclusionsThese results reveal that BMAL1 serves as a neuroprotective agent in ICH and upregulation of BMAL1 attenuates ICH-induced SBI. Therefore, BMAL1 may be a promising therapeutic target for SBI following ICH.
| S-EPMC8640921 | biostudies-literature
Project description:Inhibition of histone deacetylases (HDACs) has been shown to reduce inflammation and white matter damage after various forms of brain injury via modulation of microglia/macrophage polarization. Previously we showed that the HDAC inhibitor scriptaid could attenuate white matter injury (WMI) after ICH. To access whether modulation of microglia/macrophage polarization might underlie this protection, we investigated the modulatory role of HDAC2 in microglia/macrophage polarization in response to WMI induced by intracerebral hemorrhage (ICH) and in primary microglia and oligodendrocyte co-cultures. HDAC2 activity was inhibited via conditional knockout of the Hdac2 gene in microglia or via administration of scriptaid. Conditional knockout of the Hdac2 gene in microglia and HDAC inhibition with scriptaid both improved neurological functional recovery and reduced WMI after ICH. Additionally, HDAC inhibition shifted microglia/macrophage polarization toward the M2 phenotype and reduced proinflammatory cytokine secretion after ICH in vivo. In vitro, a transwell co-culture model of microglia and oligodendrocytes also demonstrated that the HDAC inhibitor protected oligodendrocytes by modulating microglia polarization and mitigating neuroinflammation. Moreover, we found that scriptaid decreased the expression of pJAK2 and pSTAT1 in cultured microglia when stimulated with hemoglobin. Thus, HDAC inhibition ameliorated ICH-mediated neuroinflammation and WMI by modulating microglia/macrophage polarization.
| S-EPMC8054714 | biostudies-literature