Chronic activation of microglial cells endangers neuronal survival through the release of various proinflammatory and neurotoxic factors. Berberine, the effective ingredient of Coptidis Rhizoma and Cortex Phellodendti...Chronic activation of microglial cells endangers neuronal survival through the release of various proinflammatory and neurotoxic factors. Berberine, the effective ingredient of Coptidis Rhizoma and Cortex Phellodendti, has a wide range of pharmacological functions, including anti-inflammatory, anti-atherosclerotic and anti-cancer effects. The neuroprotective potential of berberine has previously been demonstrated. The present study aimed to examine whether berberine could repress microglial activation and can be considered a potential therapeutic candidate to target neurodegenerative diseases. Primary microglial cells and BV2 microglial cells were cultured and stimulated with bacterial lipopolysaccharide （LPS）. Berberine chloride was treated prior to LPS or simultaneously with LPS stimulation. Results revealed that berberine was effective at inhibiting nitric oxide release from primary microglial cells when cells were exposed to the compound prior to LPS or simultaneously with LPS. It also reduced the LPS-stimulated production of tumor necrosis factor-α, interleukin-1β, prostaglandin E2, and intracellular reactive oxygen species and nuclear factor-kappa activation. Additionally, berberine reduced nitric oxide release from microglia stimulated with interferon-γ and amyloid β. These results suggest that berberine provides neuroprotection by reducing the production of various neurotoxic molecules from activated microglia.展开更多
Interleukin-1βis a potent proinflammatory cytokine that plays a key role in the pathogenesis of the brain aging and diverse range of neurological diseases including Alzheimer’s disease,Parkinson’s disease,stroke an...Interleukin-1βis a potent proinflammatory cytokine that plays a key role in the pathogenesis of the brain aging and diverse range of neurological diseases including Alzheimer’s disease,Parkinson’s disease,stroke and persistent pain.Activated microglia are the main cellular source of interleukin-1βin the brain.Cathepsin B is associated with the production and secretion of interleukin-1βthrough pyrin domain-containing protein 3 inflammasome-independent processing of procaspase-3 in the phagolysosomes.The leakage of cathepsin B from the endosomal-lysosomal system during aging is associated with the proteolytic degradation of mitochondrial transcription factor A,which can stabilize mitochondrial DNA.Therefore,microglial cathepsin B could function as a major driver for inflammatory brain diseases and brain aging.Orally active and blood-brain barrier-permeable specific inhibitors for cathepsin B can be potentially effective new pharmaceutical interventions against inflammatory brain diseases and brain aging.展开更多
Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead ceils must be quickly removed to avoid the further toxic effects they exert in the pa- renchyma, a ...Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead ceils must be quickly removed to avoid the further toxic effects they exert in the pa- renchyma, a process executed by microglia, the brain professional phagocytes. Although phagocytosis is critical to maintain tissue homeostasis, it has long been either overlooked or indirectly assessed based on microglial morphology, expression of classical activation markers, or engulfment of artificial phagocytic targets in vitro. Nevertheless, these indirect methods present several limitations and, thus, direct obser- vation and quantification of microglial phagocytosis is still necessary to fully grasp its relevance in the diseased brain. To overcome these caveats and obtain a comprehensive, quantitative picture of microglial phagocytosis we have developed a novel set of parameters. These parameters have allowed us to identify the different strategies utilized by microglia to cope with apoptotic challenges induced by excitotoxicity or inflammation. In contrast, we discovered that in mouse and human epilepsy microglia failed to find and engulf apoptotic ceils, resulting in accumulation of debris and inflammation. Herein, we advocate that the efficiency of microglial phagocytosis should be routinely tested in neurodegenerative and neuro- logical disorders, in order to determine the extent to which it contributes to apoptosis and inflammation found in these conditions. Finally, our findings point towards enhancing microglial phagocytosis as a novel therapeutic strategy to control tissue damage and inflammation, and accelerate recovery in brain diseases.展开更多
AIM To address the hypothesis that young, gonad-intact female mice have improved long-term recovery associated with decreased neuroinflammation compared to male mice.METHODS Eight to ten week-old male, female, and ova...AIM To address the hypothesis that young, gonad-intact female mice have improved long-term recovery associated with decreased neuroinflammation compared to male mice.METHODS Eight to ten week-old male, female, and ovariectomized(OVX) mice underwent closed cranial impact. Gonadintact female mice were injured only in estrus state. After injury, between group differences were assessed using complementary immunohistochemical staining for microglial cells at 1 h, m RNA polymerase chain reaction for inflammatory markers at 1 h after injury, Rotarod over days 1-7, and water maze on days 28-31 after injury. RESULTS Male mice had a greater area of injury(P = 0.0063), F4/80-positive cells(P = 0.032), and up regulation of inflammatory genes compared to female mice. Male and OVX mice had higher mortality after injury when compared to female mice(P = 0.043). No groupdifferences were demonstrated in Rotarod latencies(P = 0.62). OVX mice demonstrated decreased water maze latencies compared to other groups(P = 0.049). CONCLUSION Differences in mortality, long-term neurological recovery, and markers of neuroinflammation exist between female and male mice after moderate traumatic brain injury(MTBI). Unexpectedly, OVX mice have decreased long term neurological function after MTBI when compared to gonad intact male and female mice. As such, it can be concluded that the presence of female gonadal hormones may influence behavioural outcomes after MTBI, though mechanisms involved are unclear.展开更多
The emission tomographic imaging of activated microglia in the brain moves into the focus of neuroscientific research with increasing recognition of contributions of early inflammatory processes to neurodegenerative, ...The emission tomographic imaging of activated microglia in the brain moves into the focus of neuroscientific research with increasing recognition of contributions of early inflammatory processes to neurodegenerative, traumatic, cancerous and infectious diseases of the brain. Whereas the mitochondrial isoform of the 18 kDa translocator protein (TSPO1) has been the main cellular target for positron emission tomography (PET) of this type of cells for decades, alternative marker proteins in the plasma membrane of microglia challenge efforts in ligand development, recently. The present report includes PET approaches using the chemokine receptor CX3CR1 and the FR2 folate receptor in parallel to small molecule PET tracers available for in vivo visualization of the “classical” target TSPO1. It compares first and second generation of TSPO1 ligands as well as new compounds like the tetrahydrocarbazole [18F]GE-180 and the quinazoline [11C]ER176 presumed to reduce polymorphism-related inter-subject variations, with allosteric ligands for the chemokine receptor CX3CR1 and with radio labelled folate conjugates targeting the folate “cargo” receptor FR1 and the FR2 receptor characteristic for anti-inflammatory M2 microglia.展开更多
Neuropeptide and chemokine receptors of the G protein-coupled receptor (GPCR) family belong to different classes and subgroups providing different docking sites and special binding behavior at extracellular and also t...Neuropeptide and chemokine receptors of the G protein-coupled receptor (GPCR) family belong to different classes and subgroups providing different docking sites and special binding behavior at extracellular and also transmembrane domains for small molecules potentially suitable for positron emission tomography (PET). The contribution gives an overview updating developments of small-molecule, nonpeptide ligands at a selection of peptide and chemokine receptors, expressed in neurons and microglia of the brain, regarding the last five years. Orexin 1 and orexin 2 receptors (OX1R;OX2R) and neuropeptide Y1 and Y2 receptors (NPY1R, NPY2R) were chosen as representatives of Class A neuropeptide receptors, chemokine receptor CX3C (CX3CR1) as Class A, protein-activated receptor, highly expressed in activated microglia, and corticotropin releasing factor receptor 1 (CRFR1) as representative Class B1 receptor. Structural differences between binding domains and their endogenous ligands as well as parallel expression in different types of cells and generally low density of these receptors in brain tissue are factors making the search for selective and sensitive ligands more difficult than for classical GPCR receptors. Main progress in ligand development is observed for NPY receptor antagonists and orexin receptor antagonists. For orexin receptors, search for suitable ligands can be supported with modelling approaches, as recently the complete molecular structure of these receptors is available. Small molecules, binding at CRFR1, as for other Class B1 receptor ligands, in PET and investigations of pharmacodynamics revealed rather allosteric binding modes, although, the complete crystal structure of CRFR1 as prototype of Class B1 provides, hitherto, improved possibilities for understanding binding mechanisms. Highly specific as a marker of microglia among?the GPCRs, CX3CR1 is focused as target of PET during inflammation of brain and spinal cord.展开更多
OBJECTIVE Brain inflammation plays an important role in the pathophysiology of brain ischemicstroke,psychiatric and neurological diseases.During brain inflammation,microglia cells are activated and show pro-inflammato...OBJECTIVE Brain inflammation plays an important role in the pathophysiology of brain ischemicstroke,psychiatric and neurological diseases.During brain inflammation,microglia cells are activated and show pro-inflammatory M1 and anti-inflammatory M2 phenotypes,producing neurotoxic molecules and neurotrophic factors,respectively.We have previously discovered a novel natural product compound 3c exhibiting antiinflammatory effects in microglia cells,but the underlying mechanisms and its beneficial effects on brain inflammation and brain ischemia are unknown.METHODS The gene expression of M1 markers and M2 markers was measured by RT-PCR.The AMPK phosphorylation level and M2 marker CD206 protein expression were determined by Western blotting.TNFαrelease was measured by ELISA.The gene knowdown was performed by the si RNA transfection experiment.The LPS-induced brain inflammation mouse model and transient middle cerebral artery occlusion(t MCAO)stroke model were used.RESULTS We found that compound 3c inhibited M1polarization and promoted M2 polarization in LPS-stimulated BV2 and primary microglia cells,and these effects are mediated by Ca MKKβ/AMPK/JNK signaling pathway.Furthermore,compound 3c prevented M1 gene expression and enhanced M2 gene expression in a mouse model of LPS-induced neuroinflammation,and reduced the LPS-induced sickness behavior.In addition,compound 3c significantly reduced infarct volume,improved the neurological deficit,and reduced neuroinflammation in rats with acute focal cerebral ischemia.CONCLUSION Our results indicate that natural product compound 3c suppresses microglia activation by promoting M2 polarization and may provide a novel therapeutic approach to treat brain ischemic stroke associated with enhanced brain inflammation.展开更多
Interleukin-1α and interleukin-1β aggravate neuronal injury by mediating the inf1αmmatory reaction following ischemic/hypoxic brain injury. It remains unclear whether interleukin-1α and interleukin-1β are release...Interleukin-1α and interleukin-1β aggravate neuronal injury by mediating the inf1αmmatory reaction following ischemic/hypoxic brain injury. It remains unclear whether interleukin-1α and interleukin-1β are released by microglia or astrocytes. This study prepared hippocampal slices that were subsequently subjected to oxygen and glucose deprivation. Hematoxylin-eosin staining verified that neurons exhibited hypoxic changes. Results of enzyme-linked immunosorbent assay found that interleukin-1α and interleukin-1β participated in this hypoxic process. Moreover, when hypoxic injury occurred in the hippocampus, the release of interleukin-1α and interleukin-1β was mediated by the P2X4 receptor and P2X7 receptor. Immunofluorescence staining revealed that during ischemia/hypoxia, the P2X4 receptor, P2X7 receptor, interleukin-1α and interleukin-1β expression was detectable in rat hippocampal microglia, but only P2X4 receptor and P2X7 receptor expression was detected in astrocytes. Results suggested that the P2X4 receptor and P2X7 receptor, respectively, mediated interleukin-1α and interleukin-1β released by microglia, resulting in hippocampal ischemic/hypoxic injury. Astrocytes were activated, but did not synthesize or release interleukin-1α and interleukin-1β.展开更多
基金the Program of Kyung Hee University for Young Researchers in Medical Science,No.KHU-20081253
文摘Chronic activation of microglial cells endangers neuronal survival through the release of various proinflammatory and neurotoxic factors. Berberine, the effective ingredient of Coptidis Rhizoma and Cortex Phellodendti, has a wide range of pharmacological functions, including anti-inflammatory, anti-atherosclerotic and anti-cancer effects. The neuroprotective potential of berberine has previously been demonstrated. The present study aimed to examine whether berberine could repress microglial activation and can be considered a potential therapeutic candidate to target neurodegenerative diseases. Primary microglial cells and BV2 microglial cells were cultured and stimulated with bacterial lipopolysaccharide （LPS）. Berberine chloride was treated prior to LPS or simultaneously with LPS stimulation. Results revealed that berberine was effective at inhibiting nitric oxide release from primary microglial cells when cells were exposed to the compound prior to LPS or simultaneously with LPS. It also reduced the LPS-stimulated production of tumor necrosis factor-α, interleukin-1β, prostaglandin E2, and intracellular reactive oxygen species and nuclear factor-kappa activation. Additionally, berberine reduced nitric oxide release from microglia stimulated with interferon-γ and amyloid β. These results suggest that berberine provides neuroprotection by reducing the production of various neurotoxic molecules from activated microglia.
基金founded by JSPS KAKENHI,No.24390416,JP15H05015,15K15684 and JP16H01304(all to HN)
文摘Interleukin-1βis a potent proinflammatory cytokine that plays a key role in the pathogenesis of the brain aging and diverse range of neurological diseases including Alzheimer’s disease,Parkinson’s disease,stroke and persistent pain.Activated microglia are the main cellular source of interleukin-1βin the brain.Cathepsin B is associated with the production and secretion of interleukin-1βthrough pyrin domain-containing protein 3 inflammasome-independent processing of procaspase-3 in the phagolysosomes.The leakage of cathepsin B from the endosomal-lysosomal system during aging is associated with the proteolytic degradation of mitochondrial transcription factor A,which can stabilize mitochondrial DNA.Therefore,microglial cathepsin B could function as a major driver for inflammatory brain diseases and brain aging.Orally active and blood-brain barrier-permeable specific inhibitors for cathepsin B can be potentially effective new pharmaceutical interventions against inflammatory brain diseases and brain aging.
基金supported by grants from the Spanish Ministry of Economy and Competitiveness with FEDER funds to AS(BFU2015-66689,RYC-2013-12817)OA is recipient of a predoctoral fellowship from the Basque GovernmentIDA is recipient of a predoctoral fellowship from the University of the Basque Country EHU/UPV
文摘Apoptosis is a widespread phenomenon that occurs in the brain in both physiological and pathological conditions. Dead ceils must be quickly removed to avoid the further toxic effects they exert in the pa- renchyma, a process executed by microglia, the brain professional phagocytes. Although phagocytosis is critical to maintain tissue homeostasis, it has long been either overlooked or indirectly assessed based on microglial morphology, expression of classical activation markers, or engulfment of artificial phagocytic targets in vitro. Nevertheless, these indirect methods present several limitations and, thus, direct obser- vation and quantification of microglial phagocytosis is still necessary to fully grasp its relevance in the diseased brain. To overcome these caveats and obtain a comprehensive, quantitative picture of microglial phagocytosis we have developed a novel set of parameters. These parameters have allowed us to identify the different strategies utilized by microglia to cope with apoptotic challenges induced by excitotoxicity or inflammation. In contrast, we discovered that in mouse and human epilepsy microglia failed to find and engulf apoptotic ceils, resulting in accumulation of debris and inflammation. Herein, we advocate that the efficiency of microglial phagocytosis should be routinely tested in neurodegenerative and neuro- logical disorders, in order to determine the extent to which it contributes to apoptosis and inflammation found in these conditions. Finally, our findings point towards enhancing microglial phagocytosis as a novel therapeutic strategy to control tissue damage and inflammation, and accelerate recovery in brain diseases.
文摘AIM To address the hypothesis that young, gonad-intact female mice have improved long-term recovery associated with decreased neuroinflammation compared to male mice.METHODS Eight to ten week-old male, female, and ovariectomized(OVX) mice underwent closed cranial impact. Gonadintact female mice were injured only in estrus state. After injury, between group differences were assessed using complementary immunohistochemical staining for microglial cells at 1 h, m RNA polymerase chain reaction for inflammatory markers at 1 h after injury, Rotarod over days 1-7, and water maze on days 28-31 after injury. RESULTS Male mice had a greater area of injury(P = 0.0063), F4/80-positive cells(P = 0.032), and up regulation of inflammatory genes compared to female mice. Male and OVX mice had higher mortality after injury when compared to female mice(P = 0.043). No groupdifferences were demonstrated in Rotarod latencies(P = 0.62). OVX mice demonstrated decreased water maze latencies compared to other groups(P = 0.049). CONCLUSION Differences in mortality, long-term neurological recovery, and markers of neuroinflammation exist between female and male mice after moderate traumatic brain injury(MTBI). Unexpectedly, OVX mice have decreased long term neurological function after MTBI when compared to gonad intact male and female mice. As such, it can be concluded that the presence of female gonadal hormones may influence behavioural outcomes after MTBI, though mechanisms involved are unclear.
文摘The emission tomographic imaging of activated microglia in the brain moves into the focus of neuroscientific research with increasing recognition of contributions of early inflammatory processes to neurodegenerative, traumatic, cancerous and infectious diseases of the brain. Whereas the mitochondrial isoform of the 18 kDa translocator protein (TSPO1) has been the main cellular target for positron emission tomography (PET) of this type of cells for decades, alternative marker proteins in the plasma membrane of microglia challenge efforts in ligand development, recently. The present report includes PET approaches using the chemokine receptor CX3CR1 and the FR2 folate receptor in parallel to small molecule PET tracers available for in vivo visualization of the “classical” target TSPO1. It compares first and second generation of TSPO1 ligands as well as new compounds like the tetrahydrocarbazole [18F]GE-180 and the quinazoline [11C]ER176 presumed to reduce polymorphism-related inter-subject variations, with allosteric ligands for the chemokine receptor CX3CR1 and with radio labelled folate conjugates targeting the folate “cargo” receptor FR1 and the FR2 receptor characteristic for anti-inflammatory M2 microglia.
文摘Neuropeptide and chemokine receptors of the G protein-coupled receptor (GPCR) family belong to different classes and subgroups providing different docking sites and special binding behavior at extracellular and also transmembrane domains for small molecules potentially suitable for positron emission tomography (PET). The contribution gives an overview updating developments of small-molecule, nonpeptide ligands at a selection of peptide and chemokine receptors, expressed in neurons and microglia of the brain, regarding the last five years. Orexin 1 and orexin 2 receptors (OX1R;OX2R) and neuropeptide Y1 and Y2 receptors (NPY1R, NPY2R) were chosen as representatives of Class A neuropeptide receptors, chemokine receptor CX3C (CX3CR1) as Class A, protein-activated receptor, highly expressed in activated microglia, and corticotropin releasing factor receptor 1 (CRFR1) as representative Class B1 receptor. Structural differences between binding domains and their endogenous ligands as well as parallel expression in different types of cells and generally low density of these receptors in brain tissue are factors making the search for selective and sensitive ligands more difficult than for classical GPCR receptors. Main progress in ligand development is observed for NPY receptor antagonists and orexin receptor antagonists. For orexin receptors, search for suitable ligands can be supported with modelling approaches, as recently the complete molecular structure of these receptors is available. Small molecules, binding at CRFR1, as for other Class B1 receptor ligands, in PET and investigations of pharmacodynamics revealed rather allosteric binding modes, although, the complete crystal structure of CRFR1 as prototype of Class B1 provides, hitherto, improved possibilities for understanding binding mechanisms. Highly specific as a marker of microglia among?the GPCRs, CX3CR1 is focused as target of PET during inflammation of brain and spinal cord.
文摘OBJECTIVE Brain inflammation plays an important role in the pathophysiology of brain ischemicstroke,psychiatric and neurological diseases.During brain inflammation,microglia cells are activated and show pro-inflammatory M1 and anti-inflammatory M2 phenotypes,producing neurotoxic molecules and neurotrophic factors,respectively.We have previously discovered a novel natural product compound 3c exhibiting antiinflammatory effects in microglia cells,but the underlying mechanisms and its beneficial effects on brain inflammation and brain ischemia are unknown.METHODS The gene expression of M1 markers and M2 markers was measured by RT-PCR.The AMPK phosphorylation level and M2 marker CD206 protein expression were determined by Western blotting.TNFαrelease was measured by ELISA.The gene knowdown was performed by the si RNA transfection experiment.The LPS-induced brain inflammation mouse model and transient middle cerebral artery occlusion(t MCAO)stroke model were used.RESULTS We found that compound 3c inhibited M1polarization and promoted M2 polarization in LPS-stimulated BV2 and primary microglia cells,and these effects are mediated by Ca MKKβ/AMPK/JNK signaling pathway.Furthermore,compound 3c prevented M1 gene expression and enhanced M2 gene expression in a mouse model of LPS-induced neuroinflammation,and reduced the LPS-induced sickness behavior.In addition,compound 3c significantly reduced infarct volume,improved the neurological deficit,and reduced neuroinflammation in rats with acute focal cerebral ischemia.CONCLUSION Our results indicate that natural product compound 3c suppresses microglia activation by promoting M2 polarization and may provide a novel therapeutic approach to treat brain ischemic stroke associated with enhanced brain inflammation.
基金supported by the Natural Science Foundation of Guangdong Province,No.S2011010004096
文摘Interleukin-1α and interleukin-1β aggravate neuronal injury by mediating the inf1αmmatory reaction following ischemic/hypoxic brain injury. It remains unclear whether interleukin-1α and interleukin-1β are released by microglia or astrocytes. This study prepared hippocampal slices that were subsequently subjected to oxygen and glucose deprivation. Hematoxylin-eosin staining verified that neurons exhibited hypoxic changes. Results of enzyme-linked immunosorbent assay found that interleukin-1α and interleukin-1β participated in this hypoxic process. Moreover, when hypoxic injury occurred in the hippocampus, the release of interleukin-1α and interleukin-1β was mediated by the P2X4 receptor and P2X7 receptor. Immunofluorescence staining revealed that during ischemia/hypoxia, the P2X4 receptor, P2X7 receptor, interleukin-1α and interleukin-1β expression was detectable in rat hippocampal microglia, but only P2X4 receptor and P2X7 receptor expression was detected in astrocytes. Results suggested that the P2X4 receptor and P2X7 receptor, respectively, mediated interleukin-1α and interleukin-1β released by microglia, resulting in hippocampal ischemic/hypoxic injury. Astrocytes were activated, but did not synthesize or release interleukin-1α and interleukin-1β.
