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Su F, Bai F, Zhou H, Zhang Z. Microglial toll-like receptors and Alzheimer's disease. Brain Behav Immun 2016; 52:187-198. [PMID: 26526648 DOI: 10.1016/j.bbi.2015.10.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 10/09/2015] [Accepted: 10/15/2015] [Indexed: 02/08/2023] Open
Abstract
Microglial activation represents an important pathological hallmark of Alzheimer's disease (AD), and emerging data highlight the involvement of microglial toll-like receptors (TLRs) in the course of AD. TLRs have been observed to exert both beneficial and detrimental effects on AD-related pathologies, and transgenic animal models have provided direct and credible evidence for an association between TLRs and AD. Moreover, analyses of genetic polymorphisms have suggested interactions between genetic polymorphisms in TLRs and AD risk, further supporting the hypothesis that TLRs are involved in AD. In this review, we summarize the key evidence in this field. Future studies should focus on exploring the mechanisms underlying the potential roles of TLRs in AD.
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Affiliation(s)
- Fan Su
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, China.
| | - Feng Bai
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, China.
| | - Hong Zhou
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, China.
| | - Zhijun Zhang
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, China.
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Yao HC, Zhou M, Zhou YH, Wang LH, Zhang DY, Han QF, Liu T, Wu L, Tian KL, Zhang M. Intravenous high mobility group box 1 upregulates the expression of HIF-1α in the myocardium via a protein kinase B-dependent pathway in rats following acute myocardial ischemia. Mol Med Rep 2015; 13:1211-9. [PMID: 26648172 PMCID: PMC4732844 DOI: 10.3892/mmr.2015.4648] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 11/10/2015] [Indexed: 12/23/2022] Open
Abstract
The effects of intravenous high mobility group box 1 (HMGB1) on myocardial ischemia/reperfusion (I/R) injury remains to be elucidated. The purpose of the present study was to investigate the effects of intravenous HMGB1 on the expression of hypoxia inducible factor-1α (HIF-1α) in the myocardium of rats following acute myocardial ischemia, and to examine the effects of intravenous HMGB1 on myocardial I/R injury. Male Wistar rats were divided into the following groups: Sham operation group (n=10), a group exposed to ischemia for 30 min and reperfusion for 4 h (I/R group) as a control (n=10), an HMGB group, in which 100 ng/kg HMGB was administered intravenously 30 min prior to ischemia (n=10), an LY group, in whic LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K), was administered intravenously (0.3 mg/kg) 40 min prior to ischemia (n=10), and the HMGB1+LY group, in which HMGB1 (100 ng/kg) and LY294002 (0.3 mg/kg) were administered intravenously 30 min and 40 min prior to ischemia, respectively (n=10). The serum levels of cardiac troponin I (cTnI) and tumor necrosis factor-α (TNF-α), and myocardial infarct size were measured. The expression levels of phosphorylated Akt and HIF-1α were investigated using western blot analyses. The results showed that pre-treatment with HMGB1 significantly decreased serum levels of cTnI, and TNF-α, and reduced myocardial infarct size following 4 h reperfusion (all P<0.05). HMGB1 also increased the expression levels of HIF-1α and p-Akt induced by I/R (P<0.05). LY294002 was found to eliminate the effects of intravenous HMGB1 on myocardial I/R injury (P<0.05). These results suggest that intravenous pre-treatment with HMGB1 may exert its cardioprotective effects via the upregulation of the myocardial expression of HIF-1α, which may be regulated by the PI3K/Akt signaling pathway, in rats following acute myocardial I/R.
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Affiliation(s)
- Heng-Chen Yao
- Department of Cardiology, Qilu Hospital of Shandong University School of Medicine, Jinan, Shandong 250012, P.R. China
| | - Min Zhou
- Department of Cardiology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, Shandong 252000, P.R. China
| | - Yan-Hong Zhou
- Department of Cardiology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, Shandong 252000, P.R. China
| | - Lan-Hua Wang
- Department of Cardiology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, Shandong 252000, P.R. China
| | - De-Yong Zhang
- Department of Cardiology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, Shandong 252000, P.R. China
| | - Qian-Feng Han
- Department of Cardiology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, Shandong 252000, P.R. China
| | - Tao Liu
- Department of Cardiology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, Shandong 252000, P.R. China
| | - Lei Wu
- Department of Cardiology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, Shandong 252000, P.R. China
| | - Ke-Li Tian
- Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, P.R. China
| | - Mei Zhang
- Department of Cardiology, Qilu Hospital of Shandong University School of Medicine, Jinan, Shandong 250012, P.R. China
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Zhao H, Li X, Li G, Sun BO, Ren L, Zhao C. Protective effects of monosialotetrahexosylganglioside sodium on H 2O 2-induced human vascular endothelial cells. Exp Ther Med 2015; 10:947-953. [PMID: 26622420 DOI: 10.3892/etm.2015.2603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 05/14/2015] [Indexed: 11/05/2022] Open
Abstract
Monosialotetrahexosylganglioside sodium (GM1) is widely used in the treatment of central and peripheral neurological injuries. In addition to its neuroprotective activity, GM1 exerts protective effects on brain microvascular endothelial cells, although the mechanisms underlying these effects remain unclear. The aim of the present study was to clarify the protective effects and underlying mechanisms of GM1 on human umbilical vein endothelial cells (HUVECs). In this study, hydrogen peroxide (H2O2) was applied to induce the HUVEC injury. HUVECs in a logarithmic growth phase were divided into five groups, namely the control, H2O2-treated, 10-mg/l GM1, 5-mg/l GM1 and 1-mg/l GM1 groups. In all the groups, cell proliferation was detected using a Cell Counting Kit-8 assay, a flow cytometric method was applied to analyze the cell cycle and nuclear factor (NF)-κB expression was evaluated using immunofluorescence analysis. In addition, the protein expression levels of NF-κB, phosphatidylinositol 3-kinase (PI3K) and glycogen synthase kinase (GSK)-3 were detected via western blot analysis. The results indicated that GM1 exerted significant protective effects on H2O2-injured cells by increasing the ratio of cells in the S/G2 phase. Furthermore, western blot analysis revealed that PI3K expression levels were markedly increased after 24 h, as a result of the GM1 treatment, while the expression of both GSK-3 markedly decreased. In addition, the ratio of nuclear-to-cytoplasmic NF-κB expression increased in the GM1-treated cells. In summary, GM1 exhibited marked protective effects on the HUVECs, possibly due to the ability of GM1 in maintaining the integrity of the endothelium and increasing the proportion of cells undergoing mitosis, a process in which the PI3K/GSK-3 and NF-κB pathways are crucially involved.
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Affiliation(s)
- Hang Zhao
- Department of Experimental Pharmacology and Toxicology, School of Pharmaceutical Science, Jilin University, Changchun, Jilin 130021, P.R. China ; Department of Neurosurgery, Head and Neck Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Xiangjun Li
- Department of Experimental Pharmacology and Toxicology, School of Pharmaceutical Science, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Guijie Li
- Department of Otorhinolaryngology, Head and Neck Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - B O Sun
- Department of Experimental Pharmacology and Toxicology, School of Pharmaceutical Science, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Liqun Ren
- Department of Experimental Pharmacology and Toxicology, School of Pharmaceutical Science, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Conghai Zhao
- Department of Neurosurgery, Head and Neck Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
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Wang PF, Xiong XY, Chen J, Wang YC, Duan W, Yang QW. Function and mechanism of toll-like receptors in cerebral ischemic tolerance: from preconditioning to treatment. J Neuroinflammation 2015; 12:80. [PMID: 25928750 PMCID: PMC4422156 DOI: 10.1186/s12974-015-0301-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 04/13/2015] [Indexed: 01/13/2023] Open
Abstract
Increasing evidence suggests that toll-like receptors (TLRs) play an important role in cerebral ischemia-reperfusion injury. The endogenous ligands released from ischemic neurons activate the TLR signaling pathway, resulting in the production of a large number of inflammatory cytokines, thereby causing secondary inflammation damage following cerebral ischemia. However, the preconditioning for minor cerebral ischemia or the preconditioning with TLR ligands can reduce cerebral ischemic injury by regulating the TLR signaling pathway following ischemia in brain tissue (mainly, the inhibition of the TLR4/NF-κB signaling pathway and the enhancement of the interferon regulatory factor-dependent signaling), resulting in TLR ischemic tolerance. Additionally, recent studies found that postconditioning with TLR ligands after cerebral ischemia can also reduce ischemic damage through the regulation of the TLR signaling pathway, showing a significant therapeutic effect against cerebral ischemia. These studies suggest that the ischemic tolerance mediated by TLRs can serve as an important target for the prevention and treatment of cerebral ischemia. On the basis of describing the function and mechanism of TLRs in mediating cerebral ischemic damage, this review focuses on the mechanisms of cerebral ischemic tolerance induced by the preconditioning and postconditioning of TLRs and discusses the clinical application of TLRs for ischemic tolerance.
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Affiliation(s)
- Peng-Fei Wang
- Department of Neurology, Xinqiao Hospital & the Second Affiliated Hospital, the Third Military Medical University, No. 183, Xinqiao Main Street, Shapingba District, Chongqing, 400037, China. .,Department of Neurology, Weihai municipal Hospital, Weihai, 264200, China.
| | - Xiao-Yi Xiong
- Department of Neurology, Xinqiao Hospital & the Second Affiliated Hospital, the Third Military Medical University, No. 183, Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.
| | - Jing Chen
- Department of Neurology, Xinqiao Hospital & the Second Affiliated Hospital, the Third Military Medical University, No. 183, Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.
| | - Yan-Chun Wang
- Department of Neurology, Xinqiao Hospital & the Second Affiliated Hospital, the Third Military Medical University, No. 183, Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.
| | - Wei Duan
- Department of Neurology, Xinqiao Hospital & the Second Affiliated Hospital, the Third Military Medical University, No. 183, Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.
| | - Qing-Wu Yang
- Department of Neurology, Xinqiao Hospital & the Second Affiliated Hospital, the Third Military Medical University, No. 183, Xinqiao Main Street, Shapingba District, Chongqing, 400037, China.
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Zhang X, Ha T, Lu C, Lam F, Liu L, Schweitzer J, Kalbfleisch J, Kao RL, Williams DL, Li C. Poly (I:C) therapy decreases cerebral ischaemia/reperfusion injury via TLR3-mediated prevention of Fas/FADD interaction. J Cell Mol Med 2014; 19:555-65. [PMID: 25351293 PMCID: PMC4369813 DOI: 10.1111/jcmm.12456] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/05/2014] [Indexed: 12/30/2022] Open
Abstract
Toll-like receptor (TLR)-mediated signalling plays a role in cerebral ischaemia/reperfusion (I/R) injury. Modulation of TLRs has been reported to protect against cerebral I/R injury. This study examined whether modulation of TLR3 with poly (I:C) will induce protection against cerebral I/R injury. Mice were treated with or without Poly (I:C) (n = 8/group) 1 hr prior to cerebral ischaemia (60 min.) followed by reperfusion (24 hrs). Poly (I:C) pre-treatment significantly reduced the infarct volume by 57.2% compared with untreated I/R mice. Therapeutic administration of Poly (I:C), administered 30 min. after cerebral ischaemia, markedly decreased infarct volume by 34.9%. However, Poly (I:C)-induced protection was lost in TLR3 knockout mice. In poly (I:C)-treated mice, there was less neuronal damage in the hippocampus compared with untreated I/R mice. Poly (I:C) treatment induced IRF3 phosphorylation, but it inhibited NF-κB activation in the brain. Poly (I:C) also decreased I/R-induced apoptosis by attenuation of Fas/FasL-mediated apoptotic signalling. In addition, Poly (I:C) treatment decreased microglial cell caspase-3 activity. In vitro data showed that Poly (I:C) prevented hypoxia/reoxygenation (H/R)-induced interaction between Fas and FADD as well as caspase-3 and -8 activation in microglial cells. Importantly, Poly (I:C) treatment induced co-association between TLR3 and Fas. Our data suggest that Poly (I:C) decreases in cerebral I/R injury via TLR3 which associates with Fas, thereby preventing the interaction of Fas and FADD, as well as microglial cell caspase-3 and -8 activities. We conclude that TLR3 modulation by Poly (I:C) could be a potential approach for protection against ischaemic stroke.
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Affiliation(s)
- Xia Zhang
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
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Huang H, Zhong R, Xia Z, Song J, Feng L. Neuroprotective effects of rhynchophylline against ischemic brain injury via regulation of the Akt/mTOR and TLRs signaling pathways. Molecules 2014; 19:11196-210. [PMID: 25079660 PMCID: PMC6270871 DOI: 10.3390/molecules190811196] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/06/2014] [Accepted: 07/16/2014] [Indexed: 12/12/2022] Open
Abstract
Rhynchophylline (Rhy) is an alkaloid isolated from Uncaria which has long been recommended for the treatment of central nervous diseases. In our study, the neuroprotective effect of Rhy was investigated in a stroke model, namely permanent middle cerebral artery occlusion (pMCAO). Rats were injected intraperitoneally once daily for four consecutive days before surgery and then received one more injection after surgery. The protein and mRNA levels of p-Akt, p-mTOR, apoptosis-related proteins (p-BAD and cleaved caspase-3), TLR2/4/9, NF-κB, MyD88, BDNF and claudin-5 were examined. Following pMCAO, Rhy treatment not only ameliorated neurological deficits, infarct volume and brain edema, but also increased claudin-5 and BDNF expressions (p < 0.05). Moreover, Rhy could activate PI3K/Akt/mTOR signaling while inhibiting TLRs/NF-κB pathway. Wortmannin, a selective PI3K inhibitor, could abolish the neuroprotective effect of Rhy and reverse the increment in p-Akt, p-mTOR and p-BAD levels. In conclusion, we hypothesize that Rhy protected against ischemic damage, probably via regulating the Akt/mTOR pathway.
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Affiliation(s)
- Houcai Huang
- Animal Center, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, China.
| | - Rongling Zhong
- Animal Center, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, China.
| | - Zhi Xia
- Animal Center, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, China.
| | - Jie Song
- Key Laboratory of Delivery Systems of Chinese Meteria Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, China.
| | - Liang Feng
- Key Laboratory of Delivery Systems of Chinese Meteria Medica, Jiangsu Provincial Academy of Chinese Medicine, Jiangsu, Nanjing 210028, China.
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