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Dias ML, O'Connor KM, Dempsey EM, O'Halloran KD, McDonald FB. Targeting the Toll-like receptor pathway as a therapeutic strategy for neonatal infection. Am J Physiol Regul Integr Comp Physiol 2021; 321:R879-R902. [PMID: 34612068 DOI: 10.1152/ajpregu.00307.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Toll-like receptors (TLRs) are crucial transmembrane receptors that form part of the innate immune response. They play a role in the recognition of various microorganisms and their elimination from the host. TLRs have been proposed as vital immunomodulators in the regulation of multiple neonatal stressors that extend beyond infection such as oxidative stress and pain. The immune system is immature at birth and takes some time to become fully established. As such, babies are especially vulnerable to sepsis at this early stage of life. Findings suggest a gestational age-dependent increase in TLR expression. TLRs engage with accessory and adaptor proteins to facilitate recognition of pathogens and their activation of the receptor. TLRs are generally upregulated during infection and promote the transcription and release of proinflammatory cytokines. Several studies report that TLRs are epigenetically modulated by chromatin changes and promoter methylation upon bacterial infection that have long-term influences on immune responses. TLR activation is reported to modulate cardiorespiratory responses during infection and may play a key role in driving homeostatic instability observed during sepsis. Although complex, TLR signaling and downstream pathways are potential therapeutic targets in the treatment of neonatal diseases. By reviewing the expression and function of key Toll-like receptors, we aim to provide an important framework to understand the functional role of these receptors in response to stress and infection in premature infants.
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Affiliation(s)
- Maria L Dias
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Karen M O'Connor
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Eugene M Dempsey
- Irish Centre for Maternal and Child Health Research, University College Cork, Cork, Ireland.,Department of Pediatrics and Child Health, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland.,Irish Centre for Maternal and Child Health Research, University College Cork, Cork, Ireland
| | - Fiona B McDonald
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland.,Irish Centre for Maternal and Child Health Research, University College Cork, Cork, Ireland
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Suehiro H, Fukuzawa K, Yoshida N, Kiuchi K, Takami M, Akita T, Tabata T, Takemoto M, Sakai J, Nakamura T, Yatomi A, Takahara H, Sonoda Y, Nakasone K, Yamamoto K, Suzuki A, Yamashita T, Hirata KI. Circulating intermediate monocytes and toll-like receptor 4 correlate with low-voltage zones in atrial fibrillation. Heart Vessels 2020; 35:1717-1726. [DOI: 10.1007/s00380-020-01647-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/05/2020] [Indexed: 01/06/2023]
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Immune-Mediated Inflammation in Vulnerable Atherosclerotic Plaques. Molecules 2019; 24:molecules24173072. [PMID: 31450823 PMCID: PMC6749340 DOI: 10.3390/molecules24173072] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 01/16/2023] Open
Abstract
Atherosclerosis is a chronic long-lasting vascular disease leading to myocardial infarction and stroke. Vulnerable atherosclerotic (AS) plaques are responsible for these life-threatening clinical endpoints. To more successfully work against atherosclerosis, improvements in early diagnosis and treatment of AS plaque lesions are required. Vulnerable AS plaques are frequently undetectable by conventional imaging because they are non-stenotic. Although blood biomarkers like lipids, C-reactive protein, interleukin-6, troponins, and natriuretic peptides are in pathological ranges, these markers are insufficient in detecting the critical perpetuation of AS anteceding endpoints. Thus, chances to treat the patient in a preventive way are wasted. It is now time to solve this dilemma because clear results indicate a benefit of anti-inflammatory therapy per se without modification of blood lipids (CANTOS Trial, NCT01327846). This fact identifies modulation of immune-mediated inflammation as a new promising point of action for the eradication of fatal atherosclerotic endpoints.
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RAGE and TLRs as Key Targets for Antiatherosclerotic Therapy. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7675286. [PMID: 30225265 PMCID: PMC6129363 DOI: 10.1155/2018/7675286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/08/2018] [Indexed: 02/08/2023]
Abstract
Receptor for advanced glycation end-products (RAGE) and toll-like receptors (TLRs) are the key factors indicating a danger to the organism. They recognize the microbial origin pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). The primary response induced by PAMPs or DAMPs is inflammation. Excessive stimulation of the innate immune system occurs in arterial wall with the participation of effector cells. Persistent adaptive responses can also cause tissue damage and disease. However, inflammation mediated by the molecules innate responses is an important way in which the adaptive immune system protects us from infection. The specific detection of PAMPs and DAMPs by host receptors drives a cascade of signaling that converges at nuclear factor-κB (NF-κB) and interferon regulatory factors (IRFs) and induces the secretion of proinflammatory cytokines, type I interferon (IFN), and chemokines, which promote direct killing of the pathogen. Therefore, signaling of these receptors' pathways also appear to present new avenue for the modulation of inflammatory responses and to serve as potential novel therapeutic targets for antiatherosclerotic therapy.
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Zhang P, Shao L, Ma J. Toll-Like Receptors 2 and 4 Predict New-Onset Atrial Fibrillation in Acute Myocardial Infarction Patients. Int Heart J 2018; 59:64-70. [PMID: 29375116 DOI: 10.1536/ihj.17-084] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Myocardial infarction (MI) can cause new-onset atrial fibrillation (AF) due to cardiac remodeling. As a recent study has shown, inflammatory factors are closely tied to cell death and survival in myocardial ischemia injury. Toll-like receptors (TLRs) have been shown to participate in the process of myocardial infarction as innate immune factors.The subjects were divided into 3 groups: healthy controls (n = 82), MI patients (n = 84), and AFMI (new-onset atrial fibrillation after myocardial infarction) patients (n = 85). Peripheral blood mononuclear cell (PBMC) TLR mRNA expression was detected by rt-PCR. Western blot was used to analyze PBMC TLRs and their downstream signal protein expression. PBMCs were presented as TLR2 expression or TLR4 expression using flow cytometry.From mRNA to protein detection, PBMC TLR2 and TLR4 were significantly higher in the AFMI group than in the control group and MI group. A similar tendency was also observed in the expression of downstream signaling proteins. When further analyzed with TLR2 and TLR4 antibodies by flow cytometry, PBMC levels also appeared to be higher in AFMI patients than those in MI patients and the healthy control group.In our study, PBMC TLRs and their downstream signaling proteins were significantly higher in the acute myocardial infarction patients with new-onset atrial fibrillation compared with healthy people and acute myocardial infarction patients without new-onset atrial fibrillation. They have the potential to be novel biomarkers for new-onset atrial fibrillation after acute myocardial infarction.
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Affiliation(s)
- Ping Zhang
- Department of Geriatrics & Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University
| | - Liang Shao
- Department of Cardiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University
| | - Jun Ma
- Department of Cardiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University
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Peng L, Zhang Z, Zhang M, Yu X, Yao F, Tan Y, Liu D, Gong D, Chong H, Liu X, Zheng X, Tian G, Tang C. Macrophage-activating lipopeptide-2 downregulates the expression of ATP-binding cassette transporter A1 by activating the TLR2/NF-кB/ZNF202 pathway in THP-1 macrophages. Acta Biochim Biophys Sin (Shanghai) 2016; 48:363-70. [PMID: 26922321 DOI: 10.1093/abbs/gmw013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/23/2015] [Indexed: 11/12/2022] Open
Abstract
Macrophage-activating lipopeptide-2 (MALP-2) has been shown to promote the development of atherosclerosis. ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein, plays a critical role in mediating cholesterol export from macrophages to apolipoprotein A-I (apoA-I). However, whether MALP-2 can regulate the expression of ABCA1 is still largely unknown. The aim of this study was to explore the effects of MALP-2 on ABCA1 expression in THP-1 macrophages and the underlying mechanisms. Our results showed that the treatment of cells with MALP-2 decreased ABCA1 level and suppressed cholesterol efflux in both concentration- and time-dependent manners. The contents of intracellular cholesterol were significantly increased in the presence of MALP-2. Moreover, MALP-2-mediated inhibition of ABCA1 expression was abolished by siRNA of either Toll-like receptor 2 (TLR2) or nuclear factor κB (NF-κB). A similar effect was produced by treatment with the NF-κB inhibitor pyrrolidine dithiocarbamate. In addition, MALP-2-induced activation of NF-κB markedly increased zinc finger protein 202 (ZNF202) level, and ZNF202 siRNA impaired the effects of MALP-2 on ABCA1 expression. Taken together, these results suggest that MALP-2 can decrease ABCA1 expression and subsequent cholesterol efflux through activation of the TLR2/NF-κB/ZNF202 signaling pathway in THP-1 macrophages.
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Affiliation(s)
- Liangjie Peng
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China Department of Physiology, XiangNan University, Chenzhou 423000, China
| | - Zizhen Zhang
- School of Nursing, Hunan Polytechnic of Environment and Biology, Hengyang 421001, China
| | - Min Zhang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Xiaohua Yu
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Feng Yao
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Yulin Tan
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Dan Liu
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Duo Gong
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Huang Chong
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Xiaoyan Liu
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Xilong Zheng
- Department of Biochemistry and Molecular Biology, The Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, The University of Calgary, Health Sciences Center, 3330 Hospital Dr NW, Calgary, Alberta, Canada T2N 4N1
| | - Guoping Tian
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of University of South China, Hengyang 421001, China
| | - Chaoke Tang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
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Mangge H, Almer G, Stelzer I, Reininghaus E, Prassl R. Laboratory medicine for molecular imaging of atherosclerosis. Clin Chim Acta 2014; 437:19-24. [DOI: 10.1016/j.cca.2014.06.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/24/2014] [Accepted: 06/30/2014] [Indexed: 12/30/2022]
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Tan Y, Tseng PO, Wang D, Zhang H, Hunter K, Hertzberg J, Stenmark KR, Tan W. Stiffening-induced high pulsatility flow activates endothelial inflammation via a TLR2/NF-κB pathway. PLoS One 2014; 9:e102195. [PMID: 25029271 PMCID: PMC4100881 DOI: 10.1371/journal.pone.0102195] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 06/16/2014] [Indexed: 12/25/2022] Open
Abstract
Stiffening of large arteries is increasingly used as an independent predictor of risk and therapeutic outcome for small artery dysfunction in many diseases including pulmonary hypertension. The molecular mechanisms mediating downstream vascular cell responses to large artery stiffening remain unclear. We hypothesize that high pulsatility flow, induced by large artery stiffening, causes inflammatory responses in downstream pulmonary artery endothelial cells (PAECs) through toll-like receptor (TLR) pathways. To recapitulate the stiffening effect of large pulmonary arteries that occurs in pulmonary hypertension, ultrathin silicone tubes of variable mechanical stiffness were formulated and were placed in a flow circulatory system. These tubes modulated the simulated cardiac output into pulsatile flows with different pulsatility indices, 0.5 (normal) or 1.5 (high). PAECs placed downstream of the tubes were evaluated for their expression of proinflammatory molecules (ICAM-1, VCAM-1, E-selectin and MCP-1), TLR receptors and intracellular NF-κB following flow exposure. Results showed that compared to flow with normal pulsatility, high pulsatility flow induced proinflammatory responses in PAECs, enhanced TLR2 expression but not TLR4, and caused NF-κB activation. Pharmacologic (OxPAPC) and siRNA inhibition of TLR2 attenuated high pulsatility flow-induced pro-inflammatory responses and NF-κB activation in PAECs. We also observed that PAECs isolated from small pulmonary arteries of hypertensive animals exhibiting proximal vascular stiffening demonstrated a durable ex-vivo proinflammatory phenotype (increased TLR2, TLR4 and MCP-1 expression). Intralobar PAECs isolated from vessels of IPAH patients also showed increased TLR2. In conclusion, this study demonstrates for the first time that TLR2/NF-κB signaling mediates endothelial inflammation under high pulsatility flow caused by upstream stiffening, but the role of TLR4 in flow pulsatility-mediated endothelial mechanotransduction remains unclear.
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Affiliation(s)
- Yan Tan
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado, United States of America
- Department of Pediatrics, University of Colorado at Denver, Aurora, Colorado, United States of America
| | - Pi-Ou Tseng
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado, United States of America
| | - Daren Wang
- Department of Pediatrics, University of Colorado at Denver, Aurora, Colorado, United States of America
| | - Hui Zhang
- Department of Pediatrics, University of Colorado at Denver, Aurora, Colorado, United States of America
| | - Kendall Hunter
- Department of Pediatrics, University of Colorado at Denver, Aurora, Colorado, United States of America
| | - Jean Hertzberg
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado, United States of America
| | - Kurt R. Stenmark
- Department of Pediatrics, University of Colorado at Denver, Aurora, Colorado, United States of America
| | - Wei Tan
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado, United States of America
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Falck-Hansen M, Kassiteridi C, Monaco C. Toll-like receptors in atherosclerosis. Int J Mol Sci 2013; 14:14008-23. [PMID: 23880853 PMCID: PMC3742229 DOI: 10.3390/ijms140714008] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/18/2013] [Accepted: 06/22/2013] [Indexed: 12/11/2022] Open
Abstract
Atherosclerosis, the leading cause of cardiovascular disease (CVD), is driven by inflammation. Increasing evidence suggests that toll-like receptors (TLRs) are key orchestrators of the atherosclerotic disease process. Interestingly, a distinct picture is being revealed for individual receptors in atherosclerosis. TLRs exhibit a complex nature enabling the detection of multiple motifs named danger-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). Activation of these receptors triggers an intracellular signalling cascade mediated through MyD88 or TRIF, leading to the production of pro- and anti-inflammatory cytokines. In this review we explore key novel findings pertaining to TLR signalling in atherosclerosis, including recently described endosomal TLRs and future directions in TLR research.
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Affiliation(s)
- Mika Falck-Hansen
- Kennedy Institute of Rheumatology, NDORMS, University of Oxford, Roosevelt Drive, Headington, Oxford OX3 7FY, UK.
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Tauseef M, Knezevic N, Chava KR, Smith M, Sukriti S, Gianaris N, Obukhov AG, Vogel SM, Schraufnagel DE, Dietrich A, Birnbaumer L, Malik AB, Mehta D. TLR4 activation of TRPC6-dependent calcium signaling mediates endotoxin-induced lung vascular permeability and inflammation. ACTA ACUST UNITED AC 2012; 209:1953-68. [PMID: 23045603 PMCID: PMC3478927 DOI: 10.1084/jem.20111355] [Citation(s) in RCA: 172] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Lung vascular endothelial barrier disruption and the accompanying inflammation are primary pathogenic features of acute lung injury (ALI); however, the basis for the development of both remains unclear. Studies have shown that activation of transient receptor potential canonical (TRPC) channels induces Ca(2+) entry, which is essential for increased endothelial permeability. Here, we addressed the role of Toll-like receptor 4 (TLR4) intersection with TRPC6-dependent Ca(2+) signaling in endothelial cells (ECs) in mediating lung vascular leakage and inflammation. We find that the endotoxin (lipopolysaccharide; LPS) induces Ca(2+) entry in ECs in a TLR4-dependent manner. Moreover, deletion of TRPC6 renders mice resistant to endotoxin-induced barrier dysfunction and inflammation, and protects against sepsis-induced lethality. TRPC6 induces Ca(2+) entry in ECs, which is secondary to the generation of diacylglycerol (DAG) induced by LPS. Ca(2+) entry mediated by TRPC6, in turn, activates the nonmuscle myosin light chain kinase (MYLK), which not only increases lung vascular permeability but also serves as a scaffold to promote the interaction of myeloid differentiation factor 88 and IL-1R-associated kinase 4, which are required for NF-κB activation and lung inflammation. Our findings suggest that TRPC6-dependent Ca(2+) entry into ECs, secondary to TLR4-induced DAG generation, participates in mediating both lung vascular barrier disruption and inflammation induced by endotoxin.
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Affiliation(s)
- Mohammad Tauseef
- Department of Pharmacology, 2 Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL 61605, USA
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