scholarly journals S100A8 Promotes Inflammation via Toll-Like Receptor 4 After Experimental Traumatic Brain Injury

2020 ◽  
Author(s):  
Guoyuan He ◽  
Yan-Ling Han ◽  
Degang Wu ◽  
Hao Cheng ◽  
Le-An Sun ◽  
...  

Abstract Background: S100A8 is involved in the pathological processes of a variety of central nervous system(CNS) diseases related to inflammation including traumatic brain injury (TBI). However, the underlying mechanism for the induction of inflammation in the brain by S100A8 after TBI remains unclear, which was investigated in the present study.Methods: The weight-drop TBI model was used in this study. The mice were randomly assigned into 5 groups: the Sham, S100A8, S100A8 + TAK-242, TBI, and TBI + TAK-242 groups. In the S100A8 + TAK-242 and TBI + TAK-242 groups, mice were treated with TAK-242, an inhibitor of Toll-like receptor (TLR) 4, intraperitoneally at half an hour before TBI. In the S100A8 and S100A8 + TAK-242 groups, S100A8 recombinant protein was injected into the lateral ventricle of the brain. To explore the relationship between S100A8 and TLR4, Western Blot (WB), immunofluorescence, enzyme-linked immunosorbent assay (ELISA) and Nissl staining were employed. Neurological score and the brain water content were also assessed. Additionally, BV-2 microglial cells were stimulated with lipopolysaccharide (LPS) or S100A8 recombinant protein with/without TAK-242 in vitro. The expressions of the related proteins were subsequently detected with WB or ELISA.Results: The levels of S100A8 protein and pro-inflammatory cytokines were significantly increased after TBI. After intracerebroventricular administration of S100A8, the neurological scores of non-TBI animals were decreased remarkably with severe brain edema. Furthermore, the levels of TLR4, p-p65 and myeloid differentiation factor 88(MyD88) were all increased after S100A8 administration or TBI, which could be restored by TAK-242. Meanwhile, p-p65 and MyD88 were upregulated after S100A8 or LPS stimulation in vitro, which also could be suppressed by TAK-242.Conclusions: The present study demonstrated that TLR4-MyD88 pathway was activated by S100A8, which was essential to the development of inflammation in the brain after TBI.

2021 ◽  
Vol 14 ◽  
Author(s):  
Guo-Yuan He ◽  
Chen-Hui Zhao ◽  
De-Gang Wu ◽  
Hao Cheng ◽  
Le-An Sun ◽  
...  

IntroductionS100 calcium-binding protein A8 (S100A8) is also known as macrophage-related protein 8, which is involved in various pathological processes in the central nervous system post-traumatic brain injury (TBI), and plays a critical role in inducing inflammatory cytokines. Accumulating evidences have indicated that toll-like receptor 4 (TLR4) is considered to be involved in inflammatory responses post TBI. The present study was designed to analyze the hypothesis that S100A8 is the key molecule that induces inflammation via TLR4 in TBI.MethodsThe weight-drop TBI model was used and randomly implemented on mice that were categorized into six groups: Sham, NS, S100A8, S100A8+TAK-242, TBI, and TBI+TAK-242 groups. In the S100A8+TAK-242 and TBI+TAK-242 groups, at half an hour prior to the intracerebroventricular administration of S100A8 or TBI, mice were intraperitoneally treated with TAK-242 that acts as a selective antagonist and inhibitor of TLR4. Furthermore, the protein recombinant of S100A8 was injected into the lateral ventricle of the brain of mice in the S100A8 and S100A8+TAK-242 groups. Sterile normal saline was injected into the lateral ventricle in the NS group. To evaluate the association between S100A8 and TLR4, Western blot, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), and Nissl staining were employed. Simultaneously, the neurological score and brain water content were assessed. In the in vitro analysis, BV-2 microglial cells were stimulated with lipopolysaccharide LPS or S100A8 recombinant protein, with or without TAK-242. The expression of the related proteins was subsequently detected by Western blot or enzyme-linked immunosorbent assay.ResultsThe levels of S100A8 protein and pro-inflammatory cytokines were significantly elevated after TBI. There was a reduction in the neurological scores of non-TBI animals with remarkable severe brain edema after the intracerebroventricular administration of S100A8. Furthermore, the TLR4, p-p65, and myeloid differentiation factor 88 (MyD88) levels were elevated after the administration of S100A8 or TBI, which could be restored by TAK-242. Meanwhile, in the in vitro analysis, due to the stimulation of S100A8 or LPS, there was an upregulation of p-p65 and MyD88, which could also be suppressed by TAK-242.ConclusionThe present study demonstrated that the TLR4-MyD88 pathway was activated by S100A8, which is essential for the development of inflammation in the brain after TBI.


2022 ◽  
Vol 20 (2) ◽  
pp. 293-299
Author(s):  
Xueliang Gao ◽  
Zhao Wang ◽  
Peilei Jia ◽  
Yapeng Zhao ◽  
Kai Wang ◽  
...  

Purpose: To investigate the protective effect of Crataegus songarica extract (CSCE) against traumatic brain injury (TBI) in rats, and the underlying mechanism of action. Methods: A rat model of TBI was established via tracheal intubation procedure, and the rats were treated with graded doses of CSCE. Neuronal survival was determined by Nissl staining, while neuronal apoptosis was measured using TUNEL-staining. Neurological impairments were determined based on neurological severity score (NSS). Results: Treatment of TBI rats with CSCE enhanced neuronal survival and decreased TUNEL-positive cell fraction in the brain cortex. The treatment prevented elevation of NSS and suppressed mRNA and protein expression levels of IL-6 and TNF-α in brain cortex. Moreover, CSCE treatment prevented TBI-mediated suppression of activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), and attenuated hydrogen peroxide (H2O2) levels in TBI rat brain cortex. Treatment of TBI rats with CSCE down-regulated NF-κB expression, increased Nrf2 expression and up-regulated mRNA expressions of heme oxygenase 1 (HO-1) and quinine oxidoreductase 1 (NQO-1). Conclusion: These results suggest that CSCE prevents TBI-mediated reduction in neuronal survival and inhibits brain cortical neuronal death in rats. It improves NSS and inhibits inflammatory response via activation of Nrf2 pathway and targeting of NF-κB expression. Therefore, CSCE is a potential therapeutic agent for TBI.


2021 ◽  
Vol 39 (1) ◽  
pp. 73-84
Author(s):  
Jianqiang Song ◽  
Guoliang Du ◽  
Haiyun Wu ◽  
Xiangliang Gao ◽  
Zhen Yang ◽  
...  

Background: Traumatic brain injury (TBI) has been a serious public health issue. Clinically, there is an urgent need for agents to ameliorate the neuroinflammation and oxidative stress induced by TBI. Our previous research has demonstrated that quercetin could protect the neurological function. However, the detailed mechanism underlying this process remains poorly understood. Objective: This research was designed to investigate the mechanisms of quercetin to protect the cortical neurons. Methods: A modified weight-drop device was used for the TBI model. 5, 20 or 50 mg/kg quercetin was injected intraperitoneally to rats at 0.5, 12 and 24 h post TBI. Rats were sacrificed three days post injury and their cerebral cortex was obtained from the injured side. The rats were randomly assigned into three groups of equal number: TBI and quercetin group, TBI group, and Sham group. The brain water content was calculated to estimate the brain damage induced by TBI. Immunohistochemical and Western blot assays were utilized to investigate the neurobehavioral status. Enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction were performed to evaluate the inflammatory responses. The cortical oxidative stress was measured by estimating the activities of malondialdehyde, superoxide dismutase, catalase and glutathione-Px. Western blot was utilized to evaluate the expression of nuclear factor erythroid 2-related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1). Results: Quercetin attenuated the brain edema and microgliosis in TBI rats. Quercetin treatment attenuated cortical inflammatory responses and oxidative stress induced by TBI insults. Quercetin treatment activated the cortical Nrf2/HO-1 pathway in TBI rats. Conclusions: Quercetin ameliorated the TBI-induced neuroinflammation and oxidative stress in the cortex through activating the Nrf2/HO-1 pathway.


2020 ◽  
Author(s):  
Han Wang ◽  
Xiaoming Zhou ◽  
Lingyun Wu ◽  
Guangjie Liu ◽  
Weidong Xu ◽  
...  

Abstract Background: Aucubin (Au), an iridoid glycoside from natural plants, has anti-oxidative and anti-inflammatory bioactivities; however, its effects on a traumatic brain injury (TBI) model remain unknown. We explored the potential role of Au in a H 2 O 2 -induced oxidant damage in primary cortical neurons and weight-drop induced-TBI in a mouse model. Methods: In vitro experiments, the various concentrations of Au (50 μg/ml, 100 μg/ml or 200 μg/ml) were added in culture medium at 0h and 6h after neurons stimulated by H 2 O 2 (100μM). After exposed for 12 hours, neurons were collected for western blot (WB), immunofluorescence and M29,79-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. In vivo experiments, Au (20 mg/kg or 40 mg/kg) was administrated intraperitoneally at 30 min, 12 h, 24 h, and 48 h after modeling. Brain water content, neurological deficits and cognitive functions were measured at specific time, respectively. Cortical tissue around focal trauma was collected for WB, TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, Nissl staining, quantitative real time polymerase chain reaction (q-PCR), immunofluorescence/immunohistochemistry and enzyme linked immunosorbent assay (ELISA) at 72 h after TBI. RNA interference experiments were performed to determine the effects of Nuclear factor erythroid-2 related factor 2 (Nrf2) on TBI mice with Au (40 mg/kg) treatment. Mice were intracerebroventricularly administrated with lentivirus at 72 h before TBI establishment. The cortex was obtained at 72 h after TBI and used for WB and q-PCR. Results: Au enhanced the translocation of Nrf2 into the nucleus, activated antioxidant enzymes, suppressed excessive generation of reactive oxygen species (ROS) and reduced cell apoptosis both in vitro and vivo experiments. In the mice model of TBI, Au markedly attenuated brain edema, histological damages and improved neurological and cognitive deficits. Au significantly suppressed high mobility group box 1(HMGB1)-mediated aseptic inflammation. Nrf2 knockdown in TBI mice blunted the antioxidant and anti-inflammatory neuroprotective effects of the Au. Conclusions: Taken together, our data suggest that Au provides a neuroprotective effect in TBI mice model by inhibiting oxidative stress and inflammatory responses; the mechanisms involve triggering Nrf2-induced antioxidant system.


Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1487
Author(s):  
Hadeel Alyenbaawi ◽  
W. Ted Allison ◽  
Sue-Ann Mok

The accumulation of tau protein in the form of filamentous aggregates is a hallmark of many neurodegenerative diseases such as Alzheimer’s disease (AD) and chronic traumatic encephalopathy (CTE). These dementias share traumatic brain injury (TBI) as a prominent risk factor. Tau aggregates can transfer between cells and tissues in a “prion-like” manner, where they initiate the templated misfolding of normal tau molecules. This enables the spread of tau pathology to distinct parts of the brain. The evidence that tauopathies spread via prion-like mechanisms is considerable, but work detailing the mechanisms of spread has mostly used in vitro platforms that cannot fully reveal the tissue-level vectors or etiology of progression. We review these issues and then briefly use TBI and CTE as a case study to illustrate aspects of tauopathy that warrant further attention in vivo. These include seizures and sleep/wake disturbances, emphasizing the urgent need for improved animal models. Dissecting these mechanisms of tauopathy progression continues to provide fresh inspiration for the design of diagnostic and therapeutic approaches.


2018 ◽  
Vol 9 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Nianzu Yu ◽  
Si Hu ◽  
Zheng Hao

Abstract Present investigation aims to explore the protective effect of stachydrine against traumatic brain injury (TBI) and also investigate the molecular mechanism of its action. TBI was induced by the fall a hammer (450 g) from the height of 1.5 m. and later stachydrine was administered for 2 weeks starting 2 hr after the induction of TBI. Effect of stachydrine was determined by estimating modified neurological severity score (mNSS), percentage of water content in the brain and cognitive dysfunction in TBI rats. Moreover western blot assay, histopathology and enzyme linked immunosorbent assay (ELISA) tests were used to determine the effect of stachydrine on TBI injured rats. Result of the report suggests that stachydrine reduces the mNSS and percentage of water content in the brain and also attenuates the cognitive dysfunction in TBI injured rats. However data of western blot assay reports that stachydrine reduces the expression of PI3K/m-TOR/Akt pathway in the brain tissues of TBI rats. Concentration of interleukin (IL-1β), tumor necrosis factor-α (TNF-α) and interferon gamma (INF-γ) was reduces in stachydrine treated group than TBI group. Moreover expression of Nuclear factor-κB/Toll-like receptor 4 (NF-κB/TLR-4) protein was also decreased in stachydrine treated group than TBI group. Histopathology study on brain tissue reveals that the percentage of apoptotic cells was also reduced in stachydrine treated group than TBI group. Data of this investigation concludes that stachydrine protects the neuronal injury by attenuating the phosphatidylinositide 3-kinases/mammalian target of rapamycin/Protein kinase B (PI3K/m-TOR/Akt) and NF-κB/TLR-4 pathway in TBI injured rats.


2020 ◽  
Vol 5 (1) ◽  
pp. 88-96
Author(s):  
Mary R. T. Kennedy

Purpose The purpose of this clinical focus article is to provide speech-language pathologists with a brief update of the evidence that provides possible explanations for our experiences while coaching college students with traumatic brain injury (TBI). Method The narrative text provides readers with lessons we learned as speech-language pathologists functioning as cognitive coaches to college students with TBI. This is not meant to be an exhaustive list, but rather to consider the recent scientific evidence that will help our understanding of how best to coach these college students. Conclusion Four lessons are described. Lesson 1 focuses on the value of self-reported responses to surveys, questionnaires, and interviews. Lesson 2 addresses the use of immediate/proximal goals as leverage for students to update their sense of self and how their abilities and disabilities may alter their more distal goals. Lesson 3 reminds us that teamwork is necessary to address the complex issues facing these students, which include their developmental stage, the sudden onset of trauma to the brain, and having to navigate going to college with a TBI. Lesson 4 focuses on the need for college students with TBI to learn how to self-advocate with instructors, family, and peers.


2018 ◽  
pp. 110-119

Primary Objectives: By extending the scope of knowledge of the primary care optometrist, the brain injury population will have expanded access to entry level neurooptometric care by optometric providers who have a basic understanding of their neurovisual problems, be able to provide some treatment and know when to refer to their colleagues who have advanced training in neuro-optometric rehabilitation.


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