• IMMUNE NETWORK
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• 제11권6호
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• pp.342-347
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• 2011

Background: Glial cells are involved in immune and inflammatory responses in the central nervous system (CNS). Glial cells such as microglia and astrocytes also provide structural and functional support for neurons. Migration and morphological changes of CNS cells are associated with their physiological as well as pathological functions. The secreted protein lipocalin-2 (LCN2) has been previously implicated in regulation of diverse cellular processes of glia and neurons, including cell migration and morphology. Methods: Here, we employed a zebrafish model to analyze the role of LCN2 in CNS cell migration and morphology in vivo. In the first part of this study, we examined the indirect effect of LCN2 on cell migration and morphology of microglia, astrocytes, and neurons cultured in vitro. Results: Conditioned media collected from LCN2-treated astrocytes augmented migration of glia and neurons in the Boyden chamber assay. The conditioned media also increased the number of neuronal processes. Next, in order to further understand the role of LCN2 in the CNS in vivo, LCN2 was ectopically expressed in the zebrafish spinal cord. Expression of exogenous LCN2 modulated neuronal cell migration in the spinal cord of zebrafish embryos, supporting the role of LCN2 as a cell migration regulator in the CNS. Conclusion: Thus, LCN2 proteins secreted under diverse conditions may play an important role in CNS immune and inflammatory responses by controlling cell migration and morphology.

• The Korean Journal of Pain
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• 제33권1호
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• pp.30-39
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• 2020

Background: This study examined the effects of gabexate mesilate on spinal nerve ligation (SNL)-induced neuropathic pain. To confirm the involvement of gabexate mesilate on neuroinflammation, we focused on the activation of nuclear factor-κB (NF-κB) and consequent the expression of proinflammatory cytokines and inducible nitric oxide synthase (iNOS). Methods: Male Sprague-Dawley rats were used for the study. After randomization into three groups: the sham-operation group, vehicle-treated group (administered normal saline as a control), and the gabexate group (administered gabexate mesilate 20 mg/kg), SNL was performed. At the 3rd day, mechanical allodynia was confirmed using von Frey filaments, and drugs were administered intraperitoneally daily according to the group. The paw withdrawal threshold (PWT) was examined on the 3rd, 7th, and 14th day. The expressions of p65 subunit of NF-κB, interleukin (IL)-1, IL-6, tumor necrosis factor-α, and iNOS were evaluated on the 7th and 14th day following SNL. Results: The PWT was significantly higher in the gabexate group compared with the vehicle-treated group (P < 0.05). The expressions of p65, proinflammatory cytokines, and iNOS significantly decreased in the gabexate group compared with the vehicle-treated group (P < 0.05) on the 7th day. On the 14th day, the expressions of p65 and iNOS showed lower levels, but those of the proinflammatory cytokines showed no significant differences. Conclusions: Gabexate mesilate increased PWT after SNL and attenuate the progress of mechanical allodynia. These results seem to be involved with the antiinflammatory effect of gabexate mesilate via inhibition of NF-κB, proinflammatory cytokines, and nitric oxide.

• The Korean Journal of Physiology and Pharmacology
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• 제12권5호
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• pp.231-236
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• 2008

Heparin is a well-known anticoagulant widely used in various clinical settings. Interestingly, recent studies have indicated that heparin also has anti-inflammatory effects on neuroinflammation-related diseases, such as Alzheimer's disease and meningitis. However, the underlying mechanism of its actions remains unclear. In the present study, we examined the anti-inflammatory mechanism of heparin in cultured cerebral endothelial cells (CECs), and found that heparin inhibited the tumor necrosis factor $\alpha$ ($TNF{\alpha}$)-induced and nuclear factor kappa B (NF-${\kappa}B$)-dependent expression of adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), which are crucial for inflammatory responses. Heparin selectively interfered with NF-${\kappa}B$ DNA-binding activity in the nucleus, which is stimulated by $TNF{\alpha}$. In addition, non-anticoagulant 2,3-O desulfated heparin (ODS) prevented NF-${\kappa}B$ activation by $TNF{\alpha}$, suggesting that the anti-inflammatory mechanism of heparin action in CECs lies in heparin's ability to inhibit the expression of cell adhesion molecules, as opposed to its anticoagulant actions.

• Biomolecules & Therapeutics
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• 제25권2호
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• pp.149-157
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• 2017

The interleukin-1 receptor antagonist (IL-1RA) is a potential stroke treatment candidate. Intranasal delivery is a novel method thereby a therapeutic protein can be penetrated into the brain parenchyma by bypassing the blood-brain barrier. Thus, this study tested whether intranasal IL-1RA can provide neuroprotection and brain penetration in transient cerebral ischemia. In male Sprague-Dawley rats, focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 1 h. The rats simultaneously received 50 mg/kg human IL-1RA through the intranasal (IN group) or intraperitoneal route (IP group). The other rats were given 0.5 mL/kg normal saline (EC group). Neurobehavioral function, infarct size, and the concentration of the administered human IL-1RA in the brain tissue were assessed. In addition, the cellular distribution of intranasal IL-1RA in the brain and its effect on proinflammatory cytokines expression were evaluated. Intranasal IL-1RA improved neurological deficit and reduced infarct size until 7 days after MCAO (p<0.05). The concentrations of the human IL-1RA in the brain tissue 24 h after MCAO were significantly greater in the IN group than in the IP group (p<0.05). The human IL-1RA was confirmed to be co-localized with neuron and microglia. Furthermore, the IN group had lower expression of $interleukin-1{\beta}$ and tumor necrosis $factor-{\alpha}$ at 6 h after MCAO than the EC group (p<0.05). These results suggest that intranasal IL-1RA can reach the brain parenchyma more efficiently and provide superior neuroprotection in the transient focal cerebral ischemia.

• Anatomy and Cell Biology
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• 제50권3호
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• pp.207-213
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• 2017

Glycogen synthase kinase $(GSK)-3{\beta}$ and related enzymes are associated with various forms of neuroinflammation, including spinal cord injury (SCI). Our aim was to evaluate whether lithium, a non-selective inhibitor of $GSK-3{\beta}$, ameliorated SCI progression, and also to analyze whether lithium affected the expression levels of two representative $GSK-3{\beta}$-associated molecules, nuclear factor erythroid 2-related factor-2 (Nrf-2) and heme oxygenase-1 (HO-1) (a target gene of Nrf-2). Intraperitoneal lithium chloride (80 mg/kg/day for 3 days) significantly improved locomotor function at 8 days post-injury (DPI); this was maintained until 14 DPI (P<0.05). Western blotting showed significantly increased phosphorylation of $GSK-3{\beta}$ (Ser9), Nrf-2, and the Nrf-2 target HO-1 in the spinal cords of lithium-treated animals. Fewer neuropathological changes (e.g., hemorrhage, inflammatory cell infiltration, and tissue loss) were observed in the spinal cords of the lithium-treated group compared with the vehicle-treated group. Microglial activation (evaluated by measuring the immunoreactivity of ionized calcium-binding protein-1) was also significantly reduced in the lithium-treated group. These findings suggest that $GSK-3{\beta}$ becomes activated after SCI, and that a non-specific enzyme inhibitor, lithium, ameliorates rat SCI by increasing phosphorylation of $GSK-3{\beta}$ and the associated molecules Nrf-2 and HO-1.

• BMB Reports
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• 제52권10호
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• pp.613-618
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• 2019

Microglial cells are known as the main immune cells in the central nervous system, both regulating its immune response and maintaining its homeostasis. Furthermore, the antioxidant ${\alpha}-lipoic$ acid (LA) is a recognized therapeutic drug for diabetes because it can easily invade the blood-brain barrier. This study investigated the effect of ${\alpha}-LA$ on the inflammatory response in lipopolysaccharide (LPS)-treated BV-2 microglial cells. Our results revealed that ${\alpha}-LA$ significantly attenuated several inflammatory responses in BV-2 microglial cells, including pro-inflammatory cytokines, such as tumor necrosis $factor-{\alpha}$ and interleukin (IL)-6, and other cytotoxic molecules, such as nitric oxide and reactive oxygen species. In addition, ${\alpha}-LA$ inhibited the LPS-induced phosphorylation of ERK and p38 and its pharmacological properties were facilitated via the inhibition of the nuclear factor kappa B signaling pathway. Moreover, ${\alpha}-LA$ suppressed the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasomes, multiprotein complexes consisting of NLRP3 and caspase-1, which are involved in the innate immune response. Finally, ${\alpha}-LA$ decreased the genes accountable for the M1 phenotype, $IL-1{\beta}$ and ICAM1, whereas it increased the genes responsible for the M2 phenotype, MRC1 and ARG1. These findings suggest that ${\alpha}-LA$ alleviates the neuroinflammatory response by regulating microglial polarization.

• BMB Reports
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• 제52권4호
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• pp.259-264
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• 2019

Social requirements are needed for living in an aging society and individual longevity. Among them, improved health and medical cares, appropriate for an aging society are strongly demanded. Human cord blood-derived plasma (hUCP) has recently emerged for its unique anti-aging effects. In this study, we investigated brain rejuvenation, particularly olfactory function, that could be achieved by a systemic administration of young blood and its underlying mechanisms. Older than 24-month-old mice were used as an aged group and administered with intravenous injection of hUCP repetitively, eight times. Anti-aging effect of hUCP on olfactory function was evaluated by buried food finding test. To investigate the mode of action of hUCP, brain, serum and spleen of mice were collected for further ex vivo analyses. Systemic injection of hUCP improved aging-associated olfactory deficits, reducing time for finding food. In the brain, although an infiltration of activated microglia and its expression of cathepsin S remarkably decreased, significant changes of proinflammatory factors were not detected. Conversely, peripheral immune balance distinctly switched from predominance of Type 1 helper T (Th1) cells to alternative regulatory T cells (Tregs). These findings indicate that systemic administration of hUCP attenuates age-related neuroinflammation and subsequent olfactory dysfunction by modulating peripheral immune balance toward Treg cells, suggesting another therapeutic function and mechanism of hUCP administration.

• Clinical Psychopharmacology and Neuroscience
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• 제16권4호
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• pp.422-433
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• 2018

Objective: Neuropsychiatric manifestations like depression and cognitive dysfunction commonly occur in inflammatory bowel disease (IBD). In the context of the brain-gut axis model, colitis can lead to alteration of brain function in a bottom-up manner. Here, the changes in the response of the hypothalamic-pituitary-adrenal axis and inflammation-related markers in the brain in colitis were studied. Methods: Dextran sodium sulfate (DSS) was used to generate a mouse model of colitis. Mice were treated with DSS for 3 or 7 days and sacrificed. We analyzed the gene expression of brain-derived neurotrophic factor (BDNF), cyclooxygenase 2 (COX-2), and glial fibrillary acidic protein (GFAP), and the expression of GFAP, in the hippocampus, hypothalamus, and amygdala. Additionally, the levels of C-reactive protein (CRP) and serum cortisol/corticosterone were measured. Results: Alteration of inflammatory-related markers varied depending on the brain region and exposure time. In the hippocampus, COX-2 mRNA, GFAP mRNA, and GFAP expression were upregulated during exposure to DSS. However, in the hypothalamus, COX-2 mRNA was upregulated only 3 days after treatment. In the amygdala, BDNF and COX-2 mRNAs were downregulated. CRP and corticosterone expression increased with DSS treatment at day 7. Conclusion: IBD could lead to neuroinflammation in a bottom-up manner, and this effect varied according to brain region. Stress-related hormones and serum inflammatory markers, such as CRP, were upregulated from the third day of DSS treatment. Therefore, early and active intervention is required to prevent psychological and behavioral changes caused by IBD, and region-specific studies can help understand the precise mechanisms by which IBD affects the brain.

• BMB Reports
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• 제55권9호
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• pp.447-452
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• 2022

Neurogenic differentiation 1 (NeuroD1) is an essential transcription factor for neuronal differentiation, maturation, and survival, and is associated with inflammation in lipopolysaccharide (LPS)-induced glial cells; however, the concrete mechanisms are still ambiguous. Therefore, we investigated whether NeuroD1-targeting miRNAs affect inflammation and neuronal apoptosis, as well as the underlying mechanism. First, we confirmed that miR-30a-5p and miR-153-3p, which target NeuroD1, reduced NeuroD1 expression in microglia and astrocytes. In LPS-induced microglia, miR-30a-5p and miR-153-3p suppressed pro-inflammatory cytokines, reactive oxygen species, the phosphorylation of c-Jun N-terminal kinase, extracellular-signal-regulated kinase (ERK), and p38, and the expression of cyclooxygenase and inducible nitric oxide synthase (iNOS) via the NF-κB pathway. Moreover, miR-30a-5p and miR-153-3p inhibited the expression of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasomes, NLRP3, cleaved caspase-1, and IL-1β, which are involved in the innate immune response. In LPS-induced astrocytes, miR-30a-5p and miR-153-3p reduced ERK phosphorylation and iNOS expression via the STAT-3 pathway. Notably, miR-30a-5p exerted greater anti-inflammatory effects than miR-153-3p. Together, these results indicate that miR-30a-5p and miR-153-3p inhibit MAPK/NF-κB pathway in microglia as well as ERK/STAT-3 pathway in astrocytes to reduce LPS-induced neuronal apoptosis. This study highlights the importance of NeuroD1 in microglia and astrocytes neuroinflammation and suggests that it can be regulated by miR-30a-5p and miR-153-3p.

• Molecules and Cells
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• 제44권5호
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• pp.281-291
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• 2021

Tissue-resident macrophages play an important role in maintaining tissue homeostasis and innate immune defense against invading microbial pathogens. Brain-resident macrophages can be classified into microglia in the brain parenchyma and non-parenchymal brain macrophages, also known as central nervous system-associated or border-associated macrophages, in the brain-circulation interface. Microglia and non-parenchymal brain macrophages, including meningeal, perivascular, and choroid plexus macrophages, are mostly produced during embryonic development, and maintained their population by self-renewal. Microglia have gained much attention for their dual roles in the maintenance of brain homeostasis and the induction of neuroinflammation. In particular, diverse phenotypes of microglia have been increasingly identified under pathological conditions. Single-cell phenotypic analysis revealed that microglia are highly heterogenous and plastic, thus it is difficult to define the status of microglia as M1/M2 or resting/activated state due to complex nature of microglia. Meanwhile, physiological function of non-parenchymal brain macrophages remain to be fully demonstrated. In this review, we have summarized the origin and signatures of brain-resident macrophages and discussed the unique features of microglia, particularly, their phenotypic polarization, diversity of subtypes, and inflammasome responses related to neurodegenerative diseases.