Inflammation In Microglial Cells Research Articles

Short-chain fatty acids abrogate Japanese encephalitis virus-induced inflammation in microglial cells via miR-200a-3p/ZBTB20/IKβα axis.

The gut-brain axis plays a pivotal role in the physiological state of an organism. Gut microbiota-derived metabolites are known to play a role in brain disorders including neuroviral infections. Short-chain fatty acids (SCFAs) appear to quench inflammatory markers in Japanese encephalitis virus-infected microglial cells in vitro. Mechanistically, we demonstrate the interaction between miR-200a-3p and ZBTB20 in regulating the canonical nuclear factor kappa B (NF-κB) signaling pathway via transcriptional regulation of Iκβα. Findings of this study pave the way to a better understanding of SCFA mechanisms that can be used to develop strategies against viral neuroinflammation.

Acid-Responsive Dual-Targeted Nanoparticles Encapsulated Aspirin Rescue the Immune Activation and Phenotype in Autism Spectrum Disorder.

The treatment of autism spectrum disorder (ASD) is one of the most difficult challenges in neurodevelopmental diseases, because of the unclear pathogenesis research and low brain‐lesion targeting efficiency. Besides, maternal immune activation has been reported as the most mature and widely used model of ASD and aspirin‐triggered lipoxin A4 is a potent anti‐inflammatory mediator being involved in the resolution of neuroinflammation in ASD. Therefore, an aspirin encapsulated cascade drug delivery system (Asp@TMNPs) is established, which can successively target the blood–brain barrier (BBB) and microglial cells and response to the acid microenvironment in lysosome. As a result, the mitochondrial oxidative stress, DNA damage, and inflammation of microglial cells are prominently alleviated. After the treatment of Asp@TMNPs, the social interaction, stereotype behavior, and anxious condition of ASD mice are notably improved and the activation of microglial cells is inhibited. Overall, this system successively penetrates the BBB and targets microglial cells, therefore, it significantly enhances the intracephalic drug accumulation and improves anti‐neuroinflammatory efficacy of aspirin, providing a promising strategy for ASD treatment.

TMEM59 protects against cerebral ischemic stroke by suppressing pyroptosis and microglial activation

Ischemic stroke is a common disease worldwide with high mortality and disability rates. Nevertheless, pathogenesis of ischemic stroke is still vague, and finding novel therapeutic target is urgently necessary. TMEM59 (also known as dendritic cell-derived factor 1, DCF1), a type I transmembrane protein, contains a minimal 19-amino-acid peptide in its intracellular domain, and has been involved in neurological pathology. However, its biological impacts on ischemic stroke are still unknown. In this study, we provided new evidence that TMEM59 expression was significantly down-regulated upon ischemia/reperfusion (I/R). The effect of stroke insult on TMEM59 expression change was only detected in microglial cells by in vitro studies. We observed that TMEM59 knockout markedly accelerated cerebral I/R in mice induced by middle cerebral artery occlusion (MCAO), as evidenced by the elevated infarction volume, neurological deficit scores, brain water contents and neuronal death, further contributing to the abnormal behaviors for mice. We then found that microglial activation reflected by the enhanced expression of Iba-1 was dramatically potentiated by TMEM59 knockout in MCAO-treated mice. Pyroptosis was highly triggered in mice with cerebral I/R, while being further aggravated in mice with TMEM59 deletion, as proved by the considerably increased expression of NLRP3, ASC, cleaved Caspase-1, GSDMD-N, mature-IL-1β and mature-IL-18. Additionally, TMEM59 knockout mice exhibited accelerated activation of NF-κB signaling pathway compared with the wild type group of mice after MCAO operation, indicating the anabatic neuroinflammation. The effects of TMEM59 suppression on ischemic stroke were confirmed in microglial cells with exposure to oxygen-glucose deprivation/reoxygenation (OGD/R). In contrast, the in vitro studies verified that improving TMEM59 expression effectively hindered pyroptosis and inflammation in microglial cells upon OGD/R treatment. Taken together, these findings illustrated protective effects of TMEM59 against ischemic stroke through restraining pyroptosis and inflammatory response.

Knockdown of long non-coding RNA LEF1-AS1 attenuates apoptosis and inflammatory injury of microglia cells following spinal cord injury

BackgroundSpinal cord injury (SCI) is associated with health burden both at personal and societal levels. Recent assessments on the role of lncRNAs in SCI regulation have matured. Therefore, to comprehensively explore the function of lncRNA LEF1-AS1 in SCI, there is an urgent need to understand its occurrence and development.MethodsUsing in vitro experiments, we used lipopolysaccharide (LPS) to treat and establish the SCI model primarily on microglial cells. Gain- and loss of function assays of LEF1-AS1 and miR-222-5p were conducted. Cell viability and apoptosis of microglial cells were assessed via CCK8 assay and flow cytometry, respectively. Adult Sprague-Dawley (SD) rats were randomly divided into four groups: Control, SCI, sh-NC, and sh-LEF-AS1 groups. ELISA test was used to determine the expression of TNF-α and IL-6, whereas the protein level of apoptotic-related markers (Bcl-2, Bax, and cleaved caspase-3) was assessed using Western blot technique.ResultsWe revealed that LncRNA LEF1-AS1 was distinctly upregulated, whereas miR-222-5p was significantly downregulated in LPS-treated SCI and microglial cells. However, LEF1-AS1 knockdown enhanced cell viability, inhibited apoptosis, as well as inflammation of LPS-mediated microglial cells. On the contrary, miR-222-5p upregulation decreased cell viability, promoted apoptosis, and inflammation of microglial cells. Mechanistically, LEF1-AS1 served as a competitive endogenous RNA (ceRNA) by sponging miR-222-5p, targeting RAMP3. RAMP3 overexpression attenuated LEF1-AS1-mediated protective effects on LPS-mediated microglial cells from apoptosis and inflammation.ConclusionIn summary, these findings ascertain that knockdown of LEF1-AS1 impedes SCI progression via the miR-222-5p/RAMP3 axis.

Adrenomedullin 2 attenuates LPS-induced inflammation in microglia cells by receptor-mediated cAMP-PKA pathway

Inflammation plays a critical role in the development of neurodegenerative diseases. Adrenomedullin 2 (AM2), a member of the calcitonin gene-related peptide family, has been known to have anti-inflammatory effects. Here, we evaluated the anti-inflammatory effects of AM2 in LPS-activated microglia and BV2 cells. The endogenous mRNA and protein expressions of AM2, calcitonin receptor-like receptor (CLR), receptor activity-modifying proteins (RAMPs) including RAMP1, RAMP2 and RAMP3 and the production of inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were detected by RT-PCR and Western blot. Our results revealed that LPS (1 μg/mL) significantly stimulated CLR, RAMP1, RAMP2 and RAMP3 protein expressions in BV2 microglia cells, but AM2 had a significant decrease. However, the mRNA levels of AM2, CLR, and RAMP1/2/3 were all markedly increased. LPS also induced obvious increases in mRNA and protein levels of the inflammatory mediators (TNF-α, IL-1β, COX2 and iNOS). More importantly, AM2 (10 nM) administration effectively inhibited the mRNA and protein expressions of these mediators induced by LPS and increased the cAMP content in LPS-stimulated BV2 cells. Furthermore, the antagonism with AM2 receptor antagonist IMD17-47, adrenomedullin (AM) receptor antagonist by AM22-52 or the inhibition of protein kinase A (PKA) activation by P1195 effectively prevented the inhibitory role of AM2 in LPS-induced production of the above inflammatory mediators. In conclusion, AM2 inhibits LPS-induced inflammation in BV2 microglia cells that may be mainly through AM receptor-mediated cAMP-PKA pathway. Our results indicate AM2 plays an important protective role in microglia inflammation, suggesting therapeutic potential for AM2 in neuroinflammation diseases caused by activated microglia.

FBW7 protects against spinal cord injury by mitigating inflammation-associated neuronal apoptosis in mice

Spinal cord injury (SCI) leads to severe and long-lasting neurological disability. Presently, the lack of effective therapies for SCI is largely attributable to an incomplete understanding of its pathogenesis. F-box and WD repeat domain-containing protein 7 (FBW7, also known as FBXW7) is a type of E3 ubiquitin ligase complex, and plays essential roles in regulating different pathological and physiological processes. In this study, we attempted to explore the effects of FBW7 on SCI progression by the in vivo and in vitro experiments. SCI mice showed significantly reduced expression of FBW7 in spinal cord tissues. Promoting FBW7 expression via intrathecal injection of AAV9/FBW7 effectively improved locomotor function in SCI mice. Neuronal death in spinal cords of SCI mice was obviously ameliorated by FBW7 over-expression, along with greatly decreased expression of cleaved Caspase-3. In addition, microglial activation in spinal cord specimens was detected in SCI mice through increasing Iba-1 expression levels, which was, however, attenuated in SCI mice injected with AAV9/FBW7. Additionally, FBW7 over-expression dramatically restrained inflammatory response in spinal cord tissues of SCI mice, as evidenced by the down-regulated expression of tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) through blocking the activation of nuclear factor-κB (NF-κB) signaling. These anti-inflammatory effects of FBW7 were confirmed in LPS-stimulated mouse microglial BV2 cells. Finally, our in vitro studies showed that conditional medium (CM) collected from LPS-incubated BV2 cells markedly induced apoptosis in the isolated primary spinal neurons; However, this effect was overtly ameliorated by CM from LPS-exposed BV2 cells over-expressing FBW7. Thus, FBW7-regulated inflammation in microglial cells was involved in the amelioration of neuronal apoptosis during SCI development. Collectively, these findings illustrated that FBW7 expression was down-regulated in spinal cords of SCI mice, and promoting its expression could effectively mitigate SCI progression by repressing microglial inflammation and neuronal death.

A Novel Targeted and High-Efficiency Nanosystem for Combinational Therapy for Alzheimer's Disease.

Alzheimer's disease (AD) remains the most prevalent neurodegenerative disease, and no effective treatment is available yet. Metal‐ion‐triggered aggregates of amyloid‐beta (Aβ) peptide and acetylcholine imbalance are reported to be possible factors in AD pathogenesis. Thus, a combination therapy that can not only inhibit and reduce Aβ aggregation but also simultaneously regulate acetylcholine imbalance that can serve as a potential treatment for AD is needed. Here, clioquinol (metal‐ion chelating agent) and donepezil (acetylcholinesterase (AChE) inhibitor) co‐encapsulated human serum albumin (HSA) nanoparticles (dcHGT NPs) are designed, which are modified with transcriptional activator protein (TAT) and monosialotetrahexosylganglioside (GM1). The GM1 lipid and TAT peptide endow this drug delivery nanosystem with high brain entry efficiency and long‐term retention capabilities through intranasal administration. It is found that dcHGT NPs can significantly inhibit and eliminate Aβ aggregation, relieve acetylcholine‐related inflammation in microglial cells, and protect primary neurons from Aβ oligomer‐induced neurotoxicity in vitro. The alleviation of Aβ‐related inflammation and AChE‐inhibited effect further synergistically adjust acetylcholine imbalance. It is further demonstrated that dcHGT NPs reduce Aβ deposition, ameliorate neuron morphological changes, rescue memory deficits, and greatly improve acetylcholine regulation ability in vivo. This multifunctional synergetic nanosystem can be a new candidate to achieve highly efficient combination therapy for AD.

MicroRNA-665-3p attenuates oxygen-glucose deprivation-evoked microglial cell apoptosis and inflammatory response by inhibiting NF-κB signaling via targeting TRIM8

Microglial inflammation induced by ischemic stroke aggravates brain damage. MicroRNAs (miRNAs) have emerged as pivotal regulators in ischemic stroke-induced inflammation in microglial cells. miR-665-3p has been reported as a critical inflammation-associated miRNA. However, whether miR-665-3p participates in regulating microglial inflammation during ischemic stroke is underdetermined. This study investigated the potential role of miR-665-3p in stroke-induced inflammation in microglial cells using a cellular model of oxygen-glucose deprivation (OGD)-stimulated microglial cells in vitro. We found that miR-665-3p expression was decreased in microglial cells exposed to OGD treatment. Functional experiments demonstrated that the overexpression of miR-665-3p attenuated OGD-induced apoptosis and inflammation in microglial cells. Notably, tripartite motif 8 (TRIM8) was identified as a target gene of miR-665-3p. TRIM8 expression was induced by OGD treatment in microglial cells and the knockdown of TRIM8 protected microglial cells from OGD -induced cytotoxicity and inflammation. Moreover, TRIM8 knockdown or miR-665-3p overexpression blocked OGD-induced activation of nuclear factor (NF)-κB signaling in microglial cells. In addition, TRIM8 overexpression partially reversed the miR-665-3p overexpression-mediated inhibitory effect on OGD-induced inflammation in microglial cells. Taken together, these results indicate that miR-665-3p up-regulation protects microglial cells from OGD-induced apoptosis and inflammatory response by targeting TRIM8 to inhibit NF-κB signaling.

Methyl Jasmonate Protects Microglial Cells Against β-Amyloid-Induced Oxidative Stress and Inflammation via Nrf2-Dependent HO-1 Pathway.

Backgroundβ-Amyloid (Aβ) induces oxidative stress and inflammation of microglial cells, thus leading to Alzheimer’s disease. Methyl jasmonate (MeJA) is reported to have anti-inflammatory and anti-oxidant effects. However, the potential roles of MeJA in Aβ-induced cell activities and the underlying mechanism are unclear.MethodsMicroglial cell line BV-2 was stimulated by 20 μM Aβ and/or 20 μM MeJA and then divided into four groups (control, Aβ, MeJA, and Aβ+MeJA). Cell viability was detected by MTT assay. MDA, SOD activity, and ROS were detected by fluorescence spectrophotometry and immunofluorescence assay. Nrf2 and HO-1 were detected by qRT-PCR and Western blot. Furthermore, inflammatory cytokines (p-NFκB, TLR4, TNF-α, IL-1β, and IL-6) and apoptosis factors (Bcl-2, Bax, and cl-casp-3) were detected by Western blot. TUNEL assay was applied to investigate apoptosis rate. Moreover, the mechanism of how MeJA played anti-oxidative stress and anti-inflammatory roles was investigated by silencing of Nrf2 via siRNA.ResultsThe result of MTT assay showed that MeJA improved the decreased viability of BV-2 cells induced by Aβ. The detection of MDA, SOD activity, and ROS showed the oxidative stress levels were decreased in Aβ+MeJA group compared with Aβ group. Nrf2, HO-1, and SOD were significantly up-regulated in Aβ+MeJA group compared with Aβ group (p<0.01). In contrast, inflammatory cytokines were significantly down-regulated in Aβ+MeJA group compared with Aβ group (p<0.05). Similarly, the expressions of apoptosis cytokines and TUNEL assay suggested a decreased apoptosis rate in Aβ+MeJA group compared to Aβ group (p<0.01). Finally, results of Nrf2 knockdown experiment showed down-regulations of anti-oxidative stress factors (Nrf2, HO-1 and SOD), up-regulations of inflammatory cytokines, and increased ratio of Bax to Bcl in Aβ+MeJA+si-Nrf2 group compared with Aβ+MeJA group (p<0.01).ConclusionMeJA could relieve Aβ-induced oxidative stress and inflammatory response in microglial cells by activating Nrf2/HO-1 pathway.

GPETAFLR, a peptide from Lupinus angustifolius L. prevents inflammation in microglial cells and confers neuroprotection in brain

ABSTRACT Objectives: Neuroinflammation is a complex inflammatory process in the central nervous system (CNS) where microglia may play a critical role. GPETAFLR is a peptide isolated from Lupinus angustifolius L. protein hydrolysates with functional activity in mononuclear phagocytes. However, it is unknown whether GPETAFLR has neuroprotective effects. Methods: We analysed the potential anti-neuroinflammatory activity of GPETAFLR by using two different models of neuroinflammation: BV-2 microglial cells and mice with high-fat diet (HFD)-induced obesity. Results: GPETAFLR hampered LPS-induced upregulation of pro-inflammatory and M1 marker genes in BV-2 cells. This effect was accompanied by an unchanged expression of anti-inflammatory IL-10 gene and by an increased expression of M2 marker genes. GPETAFLR also increased the transcriptional activity of M2 marker genes, while the microglia population remained unchanged in number and M1/M2 status in brain of mice with high-fat diet (HFD)-induced obesity. Furthermore, GPETAFLR counteracted HFD-induced downregulation of IL-10 and upregulation of pro-inflammatory markers in the mouse brain, both at gene and protein levels. Discussion: This is the first report describing that a peptide from plant origin robustly restrained the pro-inflammatory activation of microglial cells in cultures and in brain. Our data suggest that GPETAFLR might be instrumental in maintaining CNS homeostasis by inhibiting neuroinflammation.

Hippo/YAP Pathway Plays a Critical Role in Effect of GDNF Against Aβ-Induced Inflammation in Microglial Cells.

Neuroinflammation is a critical mechanism responsible for the progression of Alzheimer's disease (AD). Recent studies reveal that Hippo/Yes-associated protein (YAP) signaling pathway is highly associated with a series of inflammation-related disorders. Glial cell line-derived neurotrophic factor (GDNF), with its neurotrophic and anti-apoptotic functions for nervous system, has been demonstrated to decrease the expression of proinflammatory mediators. Here we investigated whether Hippo/YAP signaling may affect amyloid-β (Aβ)-induced proinflammatory cytokine production in microglial cells and explored its relationship with the anti-inflammation function of GDNF. The results showed that Aβ induced a decrease in the expression of YAP in microglia cells. YAP agonist XMU-MP-1 or its overexpression in microglial cells caused decreased expression of proinflammatory cytokines, whereas YAP antagonist Verteporfin or knockdown of YAP had the opposite effect. Treatment with GDNF resulted in upregulation of YAP expression and reduced the production of proinflammatory cytokines. Meanwhile YAP knockdown weakened the function of GDNF in microglial cells. In conclusion, Hippo/YAP pathway plays a critical role in effect of GDNF against Aβ-induced inflammatory response in microglia. Targeting GDNF or Hippo/YAP signaling may be promising therapeutic approach for the treatment of AD.

Stem cells from the dental apical papilla in extracellular matrix hydrogels mitigate inflammation of microglial cells

After spinal cord injury (SCI) chronic inflammation hampers regeneration. Influencing the local microenvironment after SCI may provide a strategy to modulate inflammation and the immune response. The objectives of this work were to determine whether bone or spinal cord derived ECM hydrogels can deliver human mesenchymal stem cells from the apical papilla (SCAP) to reduce local inflammation and provide a regenerative microenvironment. Bone hydrogels (8 and 10 mg/ml, B8 and B10) and spinal cord hydrogels (8 mg/ml, S8) supplemented with fibrin possessed a gelation rate and a storage modulus compatible with spinal cord implantation. S8 and B8 impact on the expression of anti and pro-inflammatory cytokines (Arg1, Nos2, Tnf) in LPS treated microglial cells were assessed using solubilised and solid hydrogel forms. S8 significantly reduced the Nos2/Arg1 ratio and solubilised B8 significantly reduced Tnf and increased Arg1 whereas solid S8 and B8 did not impact inflammation in microglial cells. SCAP incorporation within ECM hydrogels did not impact upon SCAP immunoregulatory properties, with significant downregulation of Nos2/Arg1 ratio observed for all SCAP embedded hydrogels. Tnf expression was reduced with SCAP embedded in B8, reflecting the gene expression observed with the innate hydrogel. Thus, ECM hydrogels are suitable vehicles to deliver SCAP due to their physical properties, preservation of SCAP viability and immunomodulatory capacity.

Japanese Encephalitis Virus-induced let-7a/b interacted with the NOTCH-TLR7 pathway in microglia and facilitated neuronal death via caspase activation.

MicroRNAs (miRNAs) released from the activated microglia upon neurotropic virus infection may exacerbate the neuronal damage. Here, we identified let-7a and let-7b (let-7a/b) as one of the essential miRNAs over-expressed upon Japanese Encephalitis virus (JEV) infection and released in the culture supernatant of the JEV-infected microglial cells through extracellular vesicles. The let-7a/b was previously reported to modulate inflammation in microglial cells through Toll-like receptor 7 (TLR7) pathways; although their role in accelerating JEV pathogenesis remain unexplored. Therefore, we studied the role of let-7a/b in modulating microglia-mediated inflammation during JEV infection and investigated the effect of let-7a/b-containing exosomes on primary neurons. To this end, we examined let-7a/b and NOTCH signaling pathway in TLR7 knockdown (KD) mice. We observed that TLR7 KD or inhibition of let-7a/b suppressed the JEV-induced NOTCH activation possibly via NF-κB dependent manner and subsequently, attenuated JEV-induced TNFα production in microglial cells. Furthermore, exosomes secreted from let-7a/b over-expressed microglia when transferred to uninfected mice brain induced caspase activation. Exosomes secreted from virus-infected or let-7a/b over-expressed microglia when co-incubated with mouse neuronal (Neuro2a) cells or primary cortical neurons also facilitated caspase activation leading to neuronal death. Thus, our results provide evidence for the multifaceted role of let-7a/b miRNAs in JEV pathogenesis. Let-7a/b can interact with TLR7 and NOTCH signaling pathway and enhance TNFα release from microglia. On the other hand, the exosomes secreted by JEV-infected microglia can activate caspases in uninfected neuronal cells which possibly contribute to bystander neuronal death. Cover Image for this issue: doi: 10.1111/jnc.14506.

Carnosine Prevents Aβ-Induced Oxidative Stress and Inflammation in Microglial Cells: A Key Role of TGF-β1.

Carnosine (β-alanyl-L-histidine), a dipeptide, is an endogenous antioxidant widely distributed in excitable tissues like muscles and the brain. Carnosine is involved in cellular defense mechanisms against oxidative stress, including the inhibition of amyloid-beta (Aβ) aggregation and the scavenging of reactive species. Microglia play a central role in the pathogenesis of Alzheimer’s disease, promoting neuroinflammation through the secretion of inflammatory mediators and free radicals. However, the effects of carnosine on microglial cells and neuroinflammation are not well understood. In the present work, carnosine was tested for its ability to protect BV-2 microglial cells against oligomeric Aβ1-42-induced oxidative stress and inflammation. Carnosine prevented cell death in BV-2 cells challenged with Aβ oligomers through multiple mechanisms. Specifically, carnosine lowered the oxidative stress by decreasing NO and O2−• intracellular levels as well as the expression of iNOS and Nox enzymes. Carnosine also decreased the secretion of pro-inflammatory cytokines such as IL-1β, simultaneously rescuing IL-10 levels and increasing the expression and the release of TGF-β1. Carnosine also prevented Aβ-induced neurodegeneration in mixed neuronal cultures challenged with Aβ oligomers, and these neuroprotective effects were completely abolished by SB431542, a selective inhibitor of the type-1 TGF-β receptor. Our data suggest a multimodal mechanism of action of carnosine underlying its protective effects on microglial cells against Aβ toxicity with a key role of TGF-β1 in mediating these protective effects.

Sertraline ameliorates inflammation in CUMS mice and inhibits TNF-α-induced inflammation in microglia cells

Evidence indicates that inflammation plays a crucial role in depression. Therefore, new antidepressants might be identified by screening drugs for their anti-inflammatory actions. Sertraline hydrochloride (SERT), a widely used antidepressant, has anti-inflammatory effects in clinical studies, but the mechanism involved is unclear. In this study, we used cell and molecular biology to determine the possible anti-inflammatory mechanism of SERT in vivo and in vitro. Experimental data from the in vivo study showed that mice exposed to chronic unpredictable mild stress (CUMS) had significantly higher levels of major inflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β] and inducible nitric oxide synthase [iNOS]) in peripheral and central tissues compared with the control group. Treatment of CUMS mice with SERT significantly reduced the levels of these inflammatory cytokines and inhibited the phosphorylation of nuclear factor-κB (NF-κB) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκB-α). Moreover, SERT reduced serum levels of transaminase in CUMS mice. Our in vitro study revealed that SERT suppressed TNF-α-induced NF-κB activation in a dose-dependent manner. SERT also inhibited the TNF-α-induced nuclear translocation of NF-κB by inhibiting IκB-α phosphorylation. Furthermore, SERT inhibited TNF-α-induced inflammatory cytokines in BV2 microglia cells. SERT directly bound to TNF-α and TNF-α receptor 1 (TNFR1) to potently block TNF-α/TNFR1-triggered signaling. These results indicate that SERT might treat depression by inhibiting the activation of microglia via the NF-κB signaling pathway. This study provides a basis for the research and development of antidepressants that act to reduce inflammation and the expression of inflammatory mediators.

Liposomal prodigiosin and plasmid encoding serial GCA nucleotides reduce inflammation in microglial and astrocyte cells by ATM/ATR signaling

The aim of this study was to use liposomal structure consisting prodigiosin and plasmid encoding serial GCA nucleotides (LP/pSGCAN) to reduce inflammation in microglial cells (MGCs) and astrocyte cells (ACCs) by ATM/ATR signaling. Here, it was shown that LP/pSGCAN decreased cell viability and total RNA level. Importantly, LP/pSGCAN had more effect on ACCs than MGCs (P < 0.05). Moreover, increase of apoptosis was seen with increase of concentration. The expression of IL-1 and IL-6 were decreased and the expression of ATM and ATR were increased in treated MGCs and ACCs, which showed LP/pSGCAN could inhibit inflammation by activation of ATM/ATR pathway.

\u03b11-antitrypsin mitigates NLRP3-inflammasome activation in amyloid \u03b21\u201342-stimulated murine astrocytes

BackgroundNeuroinflammation has an essential impact on the pathogenesis and progression of Alzheimer’s disease (AD). Mostly mediated by microglia and astrocytes, inflammatory processes lead to degeneration of neuronal cells. The NLRP3-inflammasome (NOD-like receptor family, pyrin domain containing 3) is a key component of the innate immune system and its activation results in secretion of the proinflammatory effectors interleukin-1β (IL-1β) and interleukin-18 (IL-18). Under physiological conditions, cytosolic NLRP3-inflammsome is maintained in an inactive form, not able to oligomerize. Amyloid β1–42 (Aβ1–42) triggers activation of NLRP3-inflammasome in microglia and astrocytes, inducing oligomerization and thus recruitment of proinflammatory proteases. NLRP3-inflammasome was found highly expressed in human brains diagnosed with AD. Moreover, NLRP3-deficient mice carrying mutations associated with familial AD were partially protected from deficits associated with AD.The endogenous protease inhibitor α1-antitrypsin (A1AT) is known for its anti-inflammatory and anti-apoptotic properties and thus could serve as therapeutic agent for NLRP3-inhibition. A1AT protects neurons from glutamate-induced toxicity and reduces Aβ1–42-induced inflammation in microglial cells. In this study, we investigated the effect of Aβ1–42-induced NLRP3-inflammasome upregulation in primary murine astrocytes and its regulation by A1AT.MethodsPrimary cortical astrocytes from BALB/c mice were stimulated with Aβ1–42 and treated with A1AT. Regulation of NLRP3-inflammasome was examined by immunocytochemistry, PCR, western blot and ELISA. Our studies included an inhibitor of NLRP3 to elucidate direct interactions between A1AT and NLRP3-inflammasome components.ResultsOur study revealed that A1AT reduces Aβ1–42-dependent upregulation of NLRP3 at the mRNA and protein levels. Furthermore, A1AT time-dependently mitigated the expression of caspase 1 and its cleavage product IL-1β in Aβ1–42-stimulated astrocytes.ConclusionWe conclude that Aβ1–42-stimulation results in an upregulation of NLRP3, caspase 1, and its cleavage products in astrocytes. A1AT time-dependently hampers neuroinflammation by downregulation of Aβ1–42-mediated NLRP3-inflammasome expression and thus may serve as a pharmaceutical opportunity for the treatment of Alzheimer’s disease.

Protective effects of hydro-ethanolic extract of Terminalia chebula on primary microglia cells and their polarization (M1/M2 balance)

Teminalia chebula (TC) has been traditionally used in the Iranian traditional medicine (ITM) and Ayurvedic medicine primarily for neurologic disorders and inflammation. Mainly, its fruits have been applied for CNS disorders. The effects of Terminalia chebula as herbal medicine with anti-inflammatory and anti-oxidant properties were aimed on lipopolysaccharide (LPS)-induced microglial inflammation. Cytotoxicity of TC extract (0–80) µg/ml on microglial cells was evaluated using the MTT assay. Also, the protective effect of TC extract concentrations with specified amount of LPS-induced mice microglial cells was studied. The concentrations of TNF-α (Tumor Necrosis Factor-α), IL-1β (Interleukin-1β), IL-6 and PGE-2 (Prostaglandin-E2) were evaluated using ELISA. Gene expression of TNF-α, IL-1β, IL-6, COX-2 (Cyclooxygenase-2), iNOS and arginase-1 was also evaluated using the Real-Time PCR method. Nitrite oxide and urea were measured using biochemical methods. The studied concentrations of TC extract did not affect the viability of microglial cells but significantly protected the viability after treatment with LPS. The concentrations and expression levels of pro-inflammatory factors (TNF-α, IL-1β, IL-6, PGE-2, COX-2) were significantly decreased after TC extract treatment in LPS-induced microglial cells with dose dependent manner. The extract also significantly decreased the levels of nitric oxide, increased urea and down regulated the expression of nitric oxide synthesis while arginase-1 expression was enhanced. Our results suggest that TC extract reduces inflammation in microglial cells and can be used as a potential anti-inflammatory agent in central nervous system inflammatory diseases.

Triticum vulgare extract exerts an anti-inflammatory action in two in vitro models of inflammation in microglial cells.

Triticum vulgare has been extensively used in traditional medicine thanks to its properties of accelerating tissue repair. The specific extract of Triticum vulgare manufactured by Farmaceutici Damor (TVE-DAMOR) is already present in some pharmaceutical formulations used in the treatment of decubitus ulcers, skin lesions and burns. It has been recently suggested that this Triticum vulgare extract may possess potential anti-inflammatory properties. In the light of these premises the aim of the present paper was to verify the anti-inflammatory role of TVE, using the LPS-stimulated microglia model of inflammation. In particular the effect of different concentrations of TVE on the release of several mediators of inflammation such as nitric oxide, IL-6, PGE2 and TNF alpha was evaluated. More important, the anti-inflammatory effect of TVE was confirmed also in primary rat microglia cultures. The results of the present study show that TVE exerts anti-inflammatory properties since it reduces the release of all the evaluated markers of inflammation, such as NO, IL6, TNF alpha and PGE2 in LPS-activated BV2 microglial cells. Intriguingly, TVE reduced microglia activation and NO release also in primary microglia. Indeed, to verify the pathway of modulation of the inflammatory markers reported above, we found that TVE restores the cytoplasmic expression of p65 protein, kwown as specific marker associated with activation of inflammatory response. The evidence for an inhibitory activity on inflammation of this specific extract of Triticum vulgare may open the way to the possibility of a therapeutical use of the Triticum vulgare extract as an anti-inflammatory compound in certain pathological states such as burns, decubitus ulcers, folliculitis and inflammation of peripheral nerve.

Dexmedetomidine inhibits inflammation in microglia cells under stimulation of LPS and ATP by c-Fos/NLRP3/caspase-1 cascades.

NOD-like receptor 3 (NLRP3) plays critical roles in the initiation of inflammasome-mediated inflammation in microglia, thus becomes an important therapeutic target of Alzheimer's disease (AD). Dexmedetomidine (Dex), a new type of clinical anesthetic agent, shows anti-inflammatory properties and inhibits postoperative cognitive dysfunction in AD patients. The present study was aimed to investigate effect of Dex on NLRP3 activity in activated microglia and reveal the underlying mechanisms. The human microglia clone 3 (HMC3) cells were exposed to 100 ng/ml LPS and 5 mM ATP, in the presence and absence of doses of Dex. Data from ELISA and Western blot assays showed that Dex abrogated the promoting effects of LPS/ATP on the release of pro-inflammatory cytokines including IL-1β and IL-18 in the cell medium and the expression of NLRP3 and its downstream target caspase-1 in HMC3 cells. Furthermore, the present study found that exposure of HMC3 cells to LPS/ATP increased nuclear protein levels of transcription factor c-Fos, but treatment with Dex reversed the increase in c-Fos, as indicated by Western blot and immunofluorescence measures. Luciferase reported assay revealed that c-Fos can bind to the promoter region of NLRP3 gene and positively regulate the expression. These results suggest that Dex inhibiting c-Fos nuclear protein levels promoted by LPS/ATP blocks the up-regulation of NLRP3. This suggestion is supported by co-immunoprecipitation and PCR studies, in which Dex decreased the amount of c-Fos that binds to NLRP3 under the stimulation of LPS/ATP. The present study revealed that Dex inhibits inflammation in microglia cells under stimulation of LPS and ATP by c-Fos/NLRP3/caspase-1 cascades, which adds new understanding of the anti-inflammatory mechanism of Dex.