TRIM9-Mediated Resolution of Neuroinflammation Confers Neuroprotection upon Ischemic Stroke in Mice.
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SUBMITTER: Zeng J
PROVIDER: S-EPMC10521935 | biostudies-literature | 2023 Aug
REPOSITORIES: biostudies-literature
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TRIM9-Mediated Resolution of Neuroinflammation Confers Neuroprotection upon Ischemic Stroke in Mice.
Zeng Jianxiong J Wang Yaoming Y Luo Zhifei Z Chang Lin-Chun LC Yoo Ji Seung JS Yan Huan H Choi Younho Y Xie Xiaochun X Deverman Benjamin E BE Gradinaru Viviana V Gupton Stephanie L SL Zlokovic Berislav V BV Zhao Zhen Z Jung Jae U JU
Cell reports 20230818 8
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Project description:Excessive and unresolved neuroinflammation is a key component of the pathological cascade in brain injuries such as ischemic stroke. Here, we report that TRIM9, a brain-specific tripartite motif (TRIM) protein, was highly expressed in the peri-infarct areas shortly after ischemic insults in mice, but expression was decreased in aged mice, which are known to have increased neuroinflammation after stroke. Mechanistically, TRIM9 sequestered β-transducin repeat-containing protein (β-TrCP) from the Skp-Cullin-F-box ubiquitin ligase complex, blocking IκBα degradation and thereby dampening nuclear factor κB (NF-κB)-dependent proinflammatory mediator production and immune cell infiltration to limit neuroinflammation. Consequently, Trim9-deficient mice were highly vulnerable to ischemia, manifesting uncontrolled neuroinflammation and exacerbated neuropathological outcomes. Systemic administration of a recombinant TRIM9 adeno-associated virus that drove brain-wide TRIM9 expression effectively resolved neuroinflammation and alleviated neuronal death, especially in aged mice. These findings reveal that TRIM9 is essential for resolving NF-κB-dependent neuroinflammation to promote recovery and repair after brain injury and may represent an attractive therapeutic target.
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Project description:Excessive and unresolved neuroinflammation is part of the pathological cascade in brain injuries such as acute ischemia, as well as neurodegenerative diseases, including multiple sclerosis and Alzheimer’s disease. Particularly, timely resolution of inflammation is critical for the recovery and repair after brain injury. The nuclear factor-κB (NF-κB) signaling plays a central role in neuroinflammation through transcriptional induction of proinflammatory genes. Here, we report that TRIM9, a brain-specific member of the TRIpartite motif (TRIM) family with ubiquitin E3 ligase activity, is upregulated in the peri-infarct cortical areas of mouse brain upon ischemic stroke, and governs the resolution of NF-κB-mediated neuroinflammation. Mechanistically, neuronal TRIM9 sequestered β-TrCP, a component of the Skp-Cullin-F-box (SCF) E3 ligase complex, from ubiquitinating IκBα, thereby mitigating NF-κB-dependent inflammatory responses including production of proinflammatory mediators and infiltration of immune cells. Consequently, Trim9 deficient mice were highly vulnerable to ischemia, manifesting uncontrolled neuroinflammation and exacerbated neuropathological and neurological outcomes. Systemic administration of recombinant adeno-associated virus (AAV)-PHP.B, allowing brain-wide enriched TRIM9 expression, effectively resolved neuroinflammation and alleviated neuronal death in aging mice. This reveals that TRIM9 is essential for fine tuning of NF-κB-dependent neuroinflammation, and TRIM9-potentiation based therapy may offer a new approach for the treatment of stroke and inflammation-related neurological disorders.
2018-12-31 | GSE114652 | GEO
Project description:TRIM9-mediated resolution of neuroinflammation confers neuroprotection against ischemic stroke in mice
| PRJNA472064 | ENA
Project description:BackgroundEvidence exists uncovering that SRY-box transcription factor 9 (SOX9) plays a role in ischemic brain injury (IBI). Thus, the current study was conducted to elucidate the specific role of SOX9 and the mechanism by which SOX9 influenced IBI.MethodsThe IBI-associated regulatory factors were searched by bioinformatics analysis. The rat model of IBI was generated using middle cerebral artery occlusion (MCAO) treatment. Neuronal cells were exposed to oxygen-glucose deprivation (OGD). The expressions of SOX9, forkhead box O3 (FOXO3), transcription of Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2), and IκB kinase α (IKKα) in OGD-treated neuronal cells were characterized using reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay. The interaction among CITED2, IKKα, and FOXO3 was identified by chromatin immunoprecipitation (ChIP) and dual luciferase reporter gene assays. Gain- and loss-of-function experiments were performed to verify the relationship among SOX9, FOXO3, CITED2, and IKKα and to investigate their functional effects on apoptosis and the inflammatory response of OGD-treated neuronal cells as well as neurological deficit and infarct area of the rat brain.ResultsSOX9, FOXO3, CITED2, and IKKα were highly expressed in OGD-treated neuronal cells. Silencing of SOX9 inhibited OGD-induced neuronal apoptosis and inflammatory response and reduced the neurological deficit and infarct area of the brain in the rats, which were caused by MCAO but were reversed by overexpressing FOXO3, CITED2, or IKKα.ConclusionTaken together, our study suggested that upregulation of SOX9 promoted IBI though upregulation of the FOXO3/CITED2/IKKα axis, highlighting a basic therapeutic consideration for IBI treatment.
| S-EPMC8006459 | biostudies-literature
Project description:BackgroundNeuroinflammation, which is mainly mediated by excessive microglia activation, plays a major role in ischemic stroke. Overactivated microglia secrete numerous inflammatory cytokines, causing excessive inflammatory responses and ultimately exacerbating ischemic brain injury. Hence, compounds that attenuate neuroinflammation could become promising drug candidates for ischemic stroke. Fraxetin has an anti-inflammatory effect in many inflammatory diseases. However, whether it possesses an anti-inflammatory capacity in microglia-mediated neuroinflammation after ischemic brain injury is unknown. Our study aimed to investigate the suppression effect of fraxetin on neuroinflammation in lipopolysaccharide (LPS)-activated microglia and establish whether fraxetin could alleviate ischemic brain injury in a rodent model of ischemic stroke.MethodsFor the in vitro experiment, primary microglia were obtained from 1-day-old C57/BL6J mice. The cells were activated with LPS and treated with fraxetin at a non-cytotoxic concentration. Real-time PCR, enzyme-linked immunosorbent assays, and immunofluorescence staining were used to evaluate the anti-inflammatory effects of fraxetin. The potential molecular mechanisms were explored and verified through RNA-sequencing analysis, western blotting and real-time PCR. For the in vivo experiment, focal ischemia was induced by middle cerebral artery occlusion (MCAO) in 8-week-old male C57/BL6J mice. Fraxetin (5 mg/kg) or an equal volume of saline was injected into mice intraperitoneally after MCAO, and 2% 2,3,5-triphenyltetrazolium chloride staining was applied to measure infarct volume. Behavioral tests were conducted to measure neurological deficits in the mice. Real-time PCR, western blotting, and immunofluorescence staining were used to examine the expression of inflammatory cytokines and microglia activation in the ischemic penumbra.ResultsFraxetin effectively inhibited the expression of proinflammatory cytokines including inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-1 beta, and interleukin-6 in LPS-activated microglia. Fraxetin also suppressed the PI3K/Akt/NF-κB signaling pathway in activated microglia, which contributed to its anti-inflammatory effects. Furthermore, the administration of fraxetin attenuated ischemic brain injury and behavioral deficits after stroke. Finally, fraxetin was found to attenuate the activation of microglia both in vitro and in vivo.ConclusionsOur results suggest that fraxetin has a suppression effect on microglia-mediated neuroinflammation, and this effect is associated with the PI3K/Akt/NF-κB signaling pathway. Fraxetin may therefore have potential neuroprotective properties for ischemic stroke.
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Project description:Stroke is a leading cause of mortality and morbidity with a paucity of effective pharmacological treatments. We have previously identified insulin-regulated aminopeptidase (IRAP) as a potential target for the development of a new class of drugs for the treatment of stroke, as global deletion of this gene in mice significantly protected against ischemic damage. In the current study, we demonstrate that small molecular weight IRAP inhibitors reduce infarct volume and improve neurological outcome in a hypertensive animal model of ischemic stroke. The effects of two structurally distinct IRAP inhibitors (HFI419 or SJM164) were investigated in a model of stroke where the middle cerebral artery was transiently occluded with endothelin-1 in the conscious spontaneously hypertensive rat. IRAP inhibitor was administered into the lateral ventricle at 2 or 6 h after stroke, with subsequent doses delivered at 24, 48 and 70 h post-stroke. Functional outcomes were assessed prior to drug treatment, and on day 1 and 3 post-stroke. Histological analyses and neuroinflammatory cytokine profiling were conducted at 72 and 24 h post-stroke respectively. IRAP inhibitor treatment following stroke significantly reduced infarct volume and improved neurological and motor deficits. These protective effects were maintained even when the therapeutic window was extended to 6 h. Examination of the cellular architecture at 72 h post-stroke demonstrated that IRAP expression was upregulated in CD11b positive cells and activated astrocytes. Furthermore, IRAP inhibitor treatment significantly increased gene expression for interleukin 6 and C-C motif chemokine ligand 2 in the ischemic core. This study provides proof-of-principle that selective inhibition of IRAP activity with two structurally distinct IRAP inhibitors reduces infarct volume and improves functional outcome even when the first dose is administered 6 h post-stroke. This is the first direct evidence that IRAP inhibitors are a class of drug with potential use in the treatment of ischemic stroke.
| S-EPMC10643421 | biostudies-literature
Project description:BACKGROUND:Dendritic cell-associated C-type lectin-1 (Dectin-1) receptor has been reported to be involved in neuroinflammation in Alzheimer's disease and traumatic brain injury. The present study was designed to investigate the role of Dectin-1 and its downstream target spleen tyrosine kinase (Syk) in early brain injury after ischemic stroke using a focal cortex ischemic stroke model. METHODS:Adult male C57BL/6 J mice were subjected to a cerebral focal ischemia model of ischemic stroke. The neurological score, adhesive removal test, and foot-fault test were evaluated on days 1, 3, 5, and 7 after ischemic stroke. Dectin-1, Syk, phosphorylated (p)-Syk, tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS) expression was analyzed via western blotting in ischemic brain tissue after ischemic stroke and in BV2 microglial cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury in vitro. The brain infarct volume and Iba1-positive cells were evaluated using Nissl's and immunofluorescence staining, respectively. The Dectin-1 antagonist laminarin (LAM) and a selective inhibitor of Syk phosphorylation (piceatannol; PIC) were used for the intervention. RESULTS:Dectin-1, Syk, and p-Syk expression was significantly enhanced on days 3, 5, and 7 and peaked on day 3 after ischemic stroke. The Dectin-1 antagonist LAM or Syk inhibitor PIC decreased the number of Iba1-positive cells and TNF-α and iNOS expression, decreased the brain infarct volume, and improved neurological functions on day 3 after ischemic stroke. In addition, the in vitro data revealed that Dectin-1, Syk, and p-Syk expression was increased following the 3-h OGD and 0, 3, and 6 h of reperfusion in BV2 microglial cells. LAM and PIC also decreased TNF-α and iNOS expression 3 h after OGD/R induction. CONCLUSION:Dectin-1/Syk signaling plays a crucial role in inflammatory activation after ischemic stroke, and further investigation of Dectin-1/Syk signaling in stroke is warranted.
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Project description:Stroke is a leading cause of death. Stroke survivors often suffer from long-term functional disability. This study demonstrated neuroprotective effects of BMS-986020 (BMS), a selective lysophosphatidic acid receptor 1 (LPA1) antagonist under clinical trials for lung fibrosis and psoriasis, against both acute and sub-acute injuries after ischemic stroke by employing a mouse model with transient middle cerebral artery occlusion (tMCAO). BMS administration immediately after reperfusion significantly attenuated acute brain injuries including brain infarction, neurological deficits, and cell apoptosis at day 1 after tMCAO. Neuroprotective effects of BMS were preserved even when administered at 3 h after reperfusion. Neuroprotection by BMS against acute injuries was associated with attenuation of microglial activation and lipid peroxidation in post-ischemic brains. Notably, repeated BMS administration daily for 14 days after tMCAO exerted long-term neuroprotection in tMCAO-challenged mice, as evidenced by significantly attenuated neurological deficits and improved survival rate. It also attenuated brain tissue loss and cell apoptosis in post-ischemic brains. Mechanistically, it significantly enhanced neurogenesis and angiogenesis in injured brains. A single administration of BMS provided similar long-term neuroprotection except survival rate. Collectively, BMS provided neuroprotection against both acute and sub-acute injuries of ischemic stroke, indicating that BMS might be an appealing therapeutic agent to treat ischemic stroke.
| S-EPMC7695306 | biostudies-literature
Project description:BackgroundIschemic stroke-reperfusion (S/R) injury is a crucial issue in the protection of brain function after thrombolysis. The vasodilation induced by ultrasound (US)-stimulated microbubble cavitation has been applied to reduce S/R injury through sonoperfusion. The present study uses oxygen-loaded microbubbles (OMBs) with US stimulation to provide sonoperfusion and local oxygen therapy for the reduction of brain infarct size and neuroprotection after S/R.MethodsThe murine S/R model was established by photodynamic thrombosis and thrombolysis at the remote branch of the anterior cerebral artery. In vivo blood flow, partial oxygen pressure (pO2), and brain infarct staining were examined to analyze the validity of the animal model and OMB treatment results. The animal behaviors and measurement of the brain infarct area were used to evaluate long-term recovery of brain function.ResultsThe percentage of blood flow was 45 ± 3%, 70 ± 3%, and 86 ± 2% after 60 min stroke, 20 min reperfusion, and 10 min OMB treatment, respectively, demonstrating sonoperfusion, and the corresponding pO2 level was 60 ± 1%, 76 ± 2%, and 79 ± 4%, showing reoxygenation. After 14 days of treatment, a 87 ± 3% reduction in brain infarction and recovery of limb coordination were observed in S/R mice. The expression of NF-κB, HIF-1α, IL-1β, and MMP-9 was inhibited and that of eNOS, BDNF, Bcl2, and IL-10 was enhanced, indicating activation of anti-inflammatory and anti-apoptosis responses and neuroprotection. Our study demonstrated that OMB treatment combines the beneficial effects of sonoperfusion and local oxygen therapy to reduce brain infarction and activate neuroprotection to prevent S/R injury.
| S-EPMC10324216 | biostudies-literature
Project description:BACKGROUND:Remote ischemic preconditioning (RIPC) of a limb has been reported to protect against ischemic stroke. Our previous results demonstrated that the RIPC-mediated neuroprotection is associated with alterations in circulating immune cell populations. Here, we evaluated the effect of the spleen, the largest reservoir of immune cells, on RIPC-mediated neuroprotection against stroke. METHODS:Noninvasive RIPC was achieved by four repeated cycles of 5-min blood flow constriction in the hindlimbs using a tourniquet. The blood and spleens were collected before and 1 h and 3 days after preconditioning to analyze the effect of RIPC on the spleen and the correlation between splenic and peripheral lymphocytes. Moreover, spleen weight and splenic lymphocytes were compared in stroke rats with or without RIPC. Finally, splenectomy was made 1 day or 2 weeks before RIPC and 90-min middle cerebral artery occlusion (MCAO). The infarct areas and deficits were assessed. Blood was collected 1 h after RIPC and 3 days after MCAO to explore the impact of splenectomy on RIPC-induced neuroprotection and immune changes. The contralateral and ipsilateral hemispheres were collected 3 days after MCAO to detect the infiltration of immune cells after RIPC and splenectomy. RESULTS:Flow cytometry analysis demonstrated that the RIPC promptly increased the percentages of CD3+CD8+ cytotoxic T (Tc) cells in the spleen with a relatively delayed elevation in CD3+CD161+ natural killer T (NKT) and CD3-CD45RA+ B lymphocytes. The percentages of circulating lymphocytes are positively correlated with the percentages of splenic lymphocytes in normal rats. Interestingly, RIPC resulted in negative correlations between the percentages of splenic and circulating T lymphocytes, while the correlation between splenic and circulating B lymphocytes remained positive. For animals subjected to RIPC followed by MCAO, RIPC increased splenic volume with an expansion of splenic lymphocytes 3 days after MCAO. Furthermore, the removal of the spleen 1 day or 2 weeks before RIPC and MCAO reduced the protective effect of RIPC on ischemic brain injury and reversed the effects of RIPC on circulating immune cell composition. RIPC significantly reduced brain infiltration of Tc and NKT cells. Prior splenectomy showed no effect on immune cell infiltration after RIPC and stroke. CONCLUSION:These results reveal an immunomodulatory effect of the spleen, effecting mainly the spleen-derived lymphocytes, during RIPC-afforded neuroprotection against cerebral ischemia.
| S-EPMC5972448 | biostudies-literature