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Lee EH, Shin MH, Gi M, Park J, Song D, Hyun YM, Ryu JH, Seong JK, Jeon Y, Han G, Namkung W, Park MS, Choi JY. Inhibition of Pendrin by a small molecule reduces Lipopolysaccharide-induced acute Lung Injury. Theranostics 2020; 10:9913-9922. [PMID: 32929324 PMCID: PMC7481407 DOI: 10.7150/thno.46417] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/27/2020] [Indexed: 12/11/2022] Open
Abstract
Rationale: Pendrin is encoded by SLC26A4 and its mutation leads to congenital hearing loss. Additionally, pendrin is up-regulated in inflammatory airway diseases such as chronic obstructive pulmonary disease, allergic rhinitis, and asthma. In this study, the effects of a novel pendrin inhibitor, YS-01, were investigated in an LPS-induced acute lung injury (ALI) mice model, and the mechanism underlying the effect of YS-01 was examined. Methods: Lipopolysaccharide (LPS, 10 mg/kg) was intranasally instilled in wild type (WT) and pendrin-null mice. YS-01 (10 mg/kg) was administered intra-peritoneally before or after LPS inhalation. Lung injury parameters were assessed in the lung tissue and bronchoalveolar lavage fluid (BALF). Pendrin levels in the BALF of 41 patients with acute respiratory distress syndrome (ARDS) due to pneumonia and 25 control (solitary pulmonary nodule) patients were also measured. Results: LPS instillation induced lung injury in WT mice but not in pendrin-null mice. Pendrin expression was increased by LPS stimulation both in vitro and in vivo. YS-01 treatment dramatically attenuated lung injury and reduced BALF cell counts and protein concentration after LPS instillation in WT mice. Proinflammatory cytokines and NF-κB activation were suppressed by YS-01 treatment in LPS-induced ALI mice. In BALF of patients whose ARDS was caused by pneumonia, pendrin expression was up-regulated compared to that in controls (mean, 24.86 vs. 6.83 ng/mL, P < 0.001). Conclusions: A novel pendrin inhibitor, YS-01, suppressed lung injury in LPS-induced ALI mice and our data provide a new strategy for the treatment of inflammatory airway diseases including sepsis-induced ALI.
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Wang YM, Qi X, Gong FC, Chen Y, Yang ZT, Mao EQ, Chen EZ. Protective and predictive role of Mucin1 in sepsis-induced ALI/ARDS. Int Immunopharmacol 2020; 83:106438. [PMID: 32247267 DOI: 10.1016/j.intimp.2020.106438] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/19/2020] [Accepted: 03/19/2020] [Indexed: 01/10/2023]
Abstract
OBJECTIVE We aimed to investigate whether inhibition of MUC1 would aggravate sepsis-induced ALI, and explore the predictive value of plasma MUC1 for sepsis patients with or without ARDS. MATERIALS AND METHODS MUC1 siRNA pre-treatment was used to knockdown MUC1 expression in vitro. GO203 was used to inhibit the homodimerization of MUC1-C in vivo. Expression levels of MUC1, TLR 4 and HIF-1α were detected by Western blot. In addition, plasma MUC1 levels of enrolled patients were detected by ELISA on the day of admission and on the 3rd day. ROC curve was used to determine the predictive value of MUC1 in sepsis patients with ARDS. RESULTS Our results showed that inhibition of MUC1 could aggravate sepsis-induced acute lung injury and increase the expression of inflammatory cytokines in sera and BALF of sepsis mice. At the same time, we confirmed that inhibition of MUC1 could significantly decrease HIF-1α expression and thereby activate the expression level of TLR4. HIF-1α was a negative regulator of TLR-4. In addition, plasma MUC1 levels of sepsis patients with ARDS were significantly higher than those without ARDS and healthy adults. ROC curve showed that predictive value of plasma MUC1 on sepsis with ARDS on the 3rd day of enrollment was higher than the day of enrollment. CONCLUSION MUC1 could inhibit the expression of TLR-4 by stabilizing HIF-1α, thereby alleviate sepsis-induced lung injury and protect organ function. At the same time, elevated MUC1 levels in plasma had a good predictive valud on whether patients with sepsis would develop ARDS.
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Affiliation(s)
- Yu-Ming Wang
- Department of Emergency in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
| | - Xing Qi
- Department of Emergency in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
| | - Fang-Chen Gong
- Department of Emergency in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
| | - Ying Chen
- Department of Emergency in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
| | - Zhi-Tao Yang
- Department of Emergency in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
| | - En-Qiang Mao
- Department of Emergency in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
| | - Er-Zhen Chen
- Department of Emergency in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
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Wang YM, Ji R, Chen WW, Huang SW, Zheng YJ, Yang ZT, Qu HP, Chen H, Mao EQ, Chen Y, Chen EZ. Paclitaxel alleviated sepsis-induced acute lung injury by activating MUC1 and suppressing TLR-4/NF-κB pathway. DRUG DESIGN DEVELOPMENT AND THERAPY 2019; 13:3391-3404. [PMID: 31576113 PMCID: PMC6766586 DOI: 10.2147/dddt.s222296] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/01/2019] [Indexed: 12/14/2022]
Abstract
Purpose It has been reported that approximately 40% of ALI (acute lung injury) incidence resulted from sepsis. Paclitaxel, as a classic anti-cancer drug, plays an important role in the regulation of inflammation. However, we do not know whether it has a protective effect against CLP (cecal ligation and puncture)-induced septic ALI. Our study aims to illuminate the mitigative effects of paclitaxel on sepsis-induced ALI and its relevant mechanisms. Materials and methods The survival rates and organ injuries were used to evaluate the effects of paclitaxel on CLP mice. The levels of inflammatory cytokines were tested by ELISA. MUC1 siRNA pre-treatment was used to knockdown MUC1 expression in vitro. GO203 was used to inhibit the homodimerization of MUC1-C in vivo. The expression levels of MUC1, TLR 4 and p-NF-κB/p65 were detected by Western blot. Results Our results showed that paclitaxel improved the survival rates and ameliorated organ injuries especially lung injury in CLP-induced septic mice. These were accompanied by reduced inflammatory cytokines in sera and BALF (bronchoalveolar lavage fluid). We also found paclitaxel could attenuate TLR 4-NF-κB/p65 activation both in lung tissues of septic mice and LPS-stimulated lung type II epithelial cell line A549. At the upstream level, paclitaxel-upregulated expression levels of MUC1 in both in vivo and in vitro experiments. The inhibitory effects of paclitaxel on TLR 4-NF-κB/p65 activation were reversed in lung tissues of septic mice pre-treated with MUC1 inhibitor and in MUC1-knockdown A549 cells. Protection of paclitaxel on sepsis-induced ALI and decrease of inflammatory cytokines were also abolished by inhibition of MUC1. Conclusion Collectively, these results indicated paclitaxel could significantly alleviate acute lung injury in CLP-induced septic mice and LPS-stimulated lung type II epithelial cell line A549 by activating MUC1 and suppressing TLR-4/NF-κB pathway.
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Affiliation(s)
- Yu-Ming Wang
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Ran Ji
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Wei-Wei Chen
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Shun-Wei Huang
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Yan-Jun Zheng
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Zhi-Tao Yang
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Hong-Ping Qu
- Department of Critical Care Medicine, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Hao Chen
- Department of General Surgery, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - En-Qiang Mao
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Ying Chen
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Er-Zhen Chen
- Department of Emergency, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
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Vieira F, Kung JW, Bhatti F. Structure, genetics and function of the pulmonary associated surfactant proteins A and D: The extra-pulmonary role of these C type lectins. Ann Anat 2017; 211:184-201. [PMID: 28351530 DOI: 10.1016/j.aanat.2017.03.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 10/19/2022]
Abstract
The collectins family encompasses several collagenous Ca2+-dependent defense lectins that are described as pathogen recognition molecules. They play an important role in both adaptive and innate immunity. Surfactant proteins A and D are two of these proteins which were initially discovered in association with surfactant in the pulmonary system. The structure, immune and inflammatory functions, and genetic variations have been well described in relation to their roles, function and pathophysiology in the pulmonary system. Subsequently, these proteins have been discovered in a wide range of other organs and organ systems. The role of these proteins outside the pulmonary system is currently an active area of research. This review intends to provide a current overview of the genetics, structure and extra-pulmonary functions of the surfactant collectin proteins.
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Affiliation(s)
- Frederico Vieira
- Neonatal Perinatal Medicine, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
| | - Johannes W Kung
- Neonatal Perinatal Medicine, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
| | - Faizah Bhatti
- Neonatal Perinatal Medicine, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States; Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
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Groeger S, Jarzina F, Domann E, Meyle J. Porphyromonas gingivalis activates NFκB and MAPK pathways in human oral epithelial cells. BMC Immunol 2017; 18:1. [PMID: 28056810 PMCID: PMC5217430 DOI: 10.1186/s12865-016-0185-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 12/16/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The bacterial biofilm at the gingival margin induces a host immune reaction. In this local inflammation epithelial cells defend the host against bacterial challenge. Porphyromonas gingivalis (P. gingivalis), a keystone pathogen, infects epithelial cells. The aim of this study was to investigate the activation of signaling cascades in primary epithelial cells and oral cancer cell lines by a profiler PCR array. RESULTS After infection with P. gingivalis membranes the RNA of 16 to 33 of 84 key genes involved in the antibacterial immune response was up-regulated, amongst them were IKBKB (NF-κB signaling pathway), IRF5 (TLR signaling) and JUN, MAP2K4, MAPK14 and MAPK8 (MAPK pathway) in SCC-25 cells and IKBKB, IRF5, JUN, MAP2K4, MAPK14 and MAPK8 in PHGK. Statistically significant up-regulation of IKBKB (4.7 ×), MAP2K4 (4.6 ×), MAPK14 (4.2 ×) and IRF5 (9.8 ×) (p < 0.01) was demonstrated in SCC-25 cells and IKBKB (3.1 ×), MAP2K4 (4.0 ×) MAPK 14 (3.0 ×) (p < 0.05), IRF5 (3.0 ×) and JUN (7.7 ×) (p < 0.01) were up-regulated in PHGK. CONCLUSIONS P. gingivalis membrane up-regulates the expression of genes involved in downstream TLR, NFκB and MAPK signaling pathways involved in the pro-inflammatory immune response in primary and malignant oral epithelial cells.
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Affiliation(s)
- Sabine Groeger
- Department of Periodontology, Justus-Liebig-University of Giessen, Giessen, Germany.
| | - Fabian Jarzina
- Department of Periodontology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Eugen Domann
- Institute for Medical Microbiology - German Center for Infection Research, DZIF Partner Site Giessen-Marburg-Langen - Justus-Liebig-University of Giessen, Giessen, Germany
| | - Joerg Meyle
- Department of Periodontology, Justus-Liebig-University of Giessen, Giessen, Germany
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Chio CC, Wei L, Chen TG, Lin CM, Shieh JP, Yeh PS, Chen RM. Neuron-derived orphan receptor 1 transduces survival signals in neuronal cells in response to hypoxia-induced apoptotic insults. J Neurosurg 2015; 124:1654-64. [PMID: 26613168 DOI: 10.3171/2015.6.jns1535] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECT Hypoxia can induce cell death or trigger adaptive mechanisms to guarantee cell survival. Neuron-derived orphan receptor 1 (NOR-1) works as an early-response protein in response to a variety of environmental stresses. In this study, the authors evaluated the roles of NOR-1 in hypoxia-induced neuronal insults. METHODS Neuro-2a cells were exposed to oxygen/glucose deprivation (OGD). Cell viability, cell morphology, cas-pase-3 activity, DNA fragmentation, and cell apoptosis were assayed to determine the mechanisms of OGD-induced neuronal insults. RNA and protein analyses were carried out to evaluate the effects of OGD on expressions of NOR-1, cAMP response element-binding (CREB), and cellular inhibitor of apoptosis protein 2 (cIAP2) genes. Translations of these gene expressions were knocked down using RNA interference. Mice subjected to traumatic brain injury (TBI) and NOR-1 was immunodetected. RESULTS Exposure of neuro-2a cells to OGD decreased cell viability in a time-dependent manner. Additionally, OGD led to cell shrinkage, DNA fragmentation, and cell apoptosis. In parallel, treatment of neuro-2a cells with OGD time dependently increased cellular NOR-1 mRNA and protein expressions. Interestingly, administration of TBI also augmented NOR-1 levels in the impacted regions of mice. As to the mechanism, exposure to OGD increased nuclear levels of the transcription factor CREB protein. Downregulating CREB expression using RNA interference simultaneously inhibited OGD-induced NOR-1 mRNA expression. Also, levels of cIAP2 mRNA and protein in neuro-2a cells were augmented by OGD. After reducing cIAP2 translation, OGD-induced cell death was reduced. Sequentially, application of NOR-1 small interfering RNA to neuro-2a cells significantly inhibited OGD-induced cIAP2 mRNA expression and concurrently alleviated hypoxia-induced alterations in cell viability, caspase-3 activation, DNA damage, and cell apoptosis. CONCLUSIONS This study shows that NOR-1 can transduce survival signals in neuronal cells responsible for hypoxiainduced apoptotic insults through activation of a CREB/cIAP2-dependent mechanism.
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Affiliation(s)
| | - Li Wei
- Departments of 3 Neurosugery and
| | | | | | | | | | - Ruei-Ming Chen
- Comprehensive Cancer Center.,Graduate Institute of Medical Sciences, Taipei Medical University; ,Brain Disease Research Center, Wan-Fang Hospital, Taipei Medical University; and.,Anesthetics and Toxicology Research Center, Taipei Medical University Hospital, Taipei, Taiwan
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Wu TT, Tai YT, Cherng YG, Chen TG, Lin CJ, Chen TL, Chang HC, Chen RM. GATA-2 transduces LPS-induced il-1β gene expression in macrophages via a toll-like receptor 4/MD88/MAPK-dependent mechanism. PLoS One 2013; 8:e72404. [PMID: 23940812 PMCID: PMC3735524 DOI: 10.1371/journal.pone.0072404] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 07/10/2013] [Indexed: 12/15/2022] Open
Abstract
Lipopolysaccharide (LPS) is a critical factor for inducing acute lung injury. GATA-2, a transcription factor, contributes to the control of cell activity and function. Exposure of RAW 264.7 cells to LPS induced interleukin (IL)-1β mRNA and protein expression and GATA-2 translocation from the cytoplasm to nuclei in concentration- and time-dependent manners. A bioinformatic search revealed that GATA-2-specific binding elements exist in the 5'-promoter region of the il-1β gene. LPS could enhance the transactivation activity of GATA-2 in macrophages. Knocking-down translation of GATA-2 mRNA using RNA interference significantly alleviated LPS-induced IL-1β mRNA and protein expression. As to the mechanism, transfection of toll-like receptor (TLR) 4 small interfering (si)RNA into macrophages concurrently decreased LPS-caused increases in nuclear GATA-2 levels. Sequentially, treatment with myeloid differentiation factor 88 (MyD88) siRNA decreased LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs) kinase 1/2 and subsequent translocation of GATA-2. Reducing MAPK activities using specific inhibitors simultaneously decreased GATA-2 activation. Furthermore, exposure of primary macrophages to LPS significantly increased the transactivation activities of GATA-2 and IL-1β mRNA and protein expression. Transfection of GATA-2 siRNA inhibited LPS-induced IL-1β mRNA expression. Results of this study show that LPS induction of il-1β gene expression in macrophages is mediated by GATA-2 via activation of TLR4, MyD88, and MAPKs.
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Affiliation(s)
- Tsu-Tuan Wu
- Graduate Institute of Medical Sciences and Center of Excellent Cancer Research, Taipei Medical University, Taipei, Taiwan
- Section of Respiratory and Critical Care Medicine, Department of Internal Medicine, Taipei County Hospital, Taipei, Taiwan
| | - Yu-Ting Tai
- Department of Anesthesiology, Wan-Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yih-Giun Cherng
- Department of Anesthesiology, Shuang-Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Tyng-Guey Chen
- Department of Anesthesiology, Wan-Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chien-Ju Lin
- Graduate Institute of Medical Sciences and Center of Excellent Cancer Research, Taipei Medical University, Taipei, Taiwan
| | - Ta-Liang Chen
- Anesthetics and Toxicology Research Center, Department of Anesthesiology, Taipei Medical University Hospital, Taipei, Taiwan
| | - Huai-Chia Chang
- Anesthetics and Toxicology Research Center, Department of Anesthesiology, Taipei Medical University Hospital, Taipei, Taiwan
| | - Ruei-Ming Chen
- Graduate Institute of Medical Sciences and Center of Excellent Cancer Research, Taipei Medical University, Taipei, Taiwan
- Anesthetics and Toxicology Research Center, Department of Anesthesiology, Taipei Medical University Hospital, Taipei, Taiwan
- Cell Physiology and Molecular Image Research Center, Wan-Fang Hospital, Taipei Medical University, Taipei, Taiwan
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Montalbano AP, Hawgood S, Mendelson CR. Mice deficient in surfactant protein A (SP-A) and SP-D or in TLR2 manifest delayed parturition and decreased expression of inflammatory and contractile genes. Endocrinology 2013; 154. [PMID: 23183169 PMCID: PMC3529364 DOI: 10.1210/en.2012-1797] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Previously we obtained compelling evidence that the fetus provides a critical signal for the initiation of term labor through developmental induction of surfactant protein (SP)-A expression by the fetal lung and secretion into amniotic fluid (AF). We proposed that interactions of AF macrophage (Mϕ) Toll-like receptors (TLRs) with SP-A, at term, or bacterial components, at preterm, result in their activation and migration to the pregnant uterus. Herein the timing of labor in wild-type (WT) C57BL/6 mice was compared with mice homozygous null for TLR2, SP-A, SP-D, or doubly deficient in SP-A and SP-D. Interestingly, TLR2(-/-) females manifested a significant (P < 0.001) delay in timing of labor compared with WT as well as reduced expression of the myometrial contraction-associated protein (CAP) gene, connexin-43, and Mϕ marker, F4/80, at 18.5 d postcoitum (dpc). Whereas in first pregnancies, SP-A(-/-), SP-D(-/-), and SP-A/D(-/-) females delivered at term (∼19.5 dpc), in second pregnancies, parturition was delayed by approximately 12 h in SP-A(-/-) (P = 0.07) and in SP-A/D(-/-) (P <0.001) females. Myometrium of SP-A/D(-/-) females expressed significantly lower levels of IL-1β, IL-6, and CAP genes, connexin-43, and oxytocin receptor at 18.5 dpc compared with WT. F4/80(+) AF Mϕs from TLR2(-/-) and SP-A/D(-/-) mice expressed significantly lower levels of both proinflammatory and antiinflammatory activation markers (e.g. IL-1β, IL-6, ARG1, YM1) compared with gestation-matched WT AF Mϕs. These novel findings suggest that the pulmonary collectins acting via TLR2 serve a modulatory role in the timing of labor; their relative impact may be dependent on parity.
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Affiliation(s)
- Alina P Montalbano
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA
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Liu FL, Chuang CY, Tai YT, Tang HL, Chen TG, Chen TL, Chen RM. Lipoteichoic acid induces surfactant protein-A biosynthesis in human alveolar type II epithelial cells through activating the MEK1/2-ERK1/2-NF-κB pathway. Respir Res 2012; 13:88. [PMID: 23031213 PMCID: PMC3492077 DOI: 10.1186/1465-9921-13-88] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 10/01/2012] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Lipoteichoic acid (LTA), a gram-positive bacterial outer membrane component, can cause septic shock. Our previous studies showed that the gram-negative endotoxin, lipopolysaccharide (LPS), could induce surfactant protein-A (SP-A) production in human alveolar epithelial (A549) cells. OBJECTIVES In this study, we further evaluated the effect of LTA on SP-A biosynthesis and its possible signal-transducing mechanisms. METHODS A549 cells were exposed to LTA. Levels of SP-A, nuclear factor (NF)-κB, extracellular signal-regulated kinase 1/2 (ERK1/2), and mitogen-activated/extracellular signal-regulated kinase kinase (MEK)1 were determined. RESULTS Exposure of A549 cells to 10, 30, and 50 μg/ml LTA for 24 h did not affect cell viability. Meanwhile, when exposed to 30 μg/ml LTA for 1, 6, and 24 h, the biosynthesis of SP-A mRNA and protein in A549 cells significantly increased. As to the mechanism, LTA enhanced cytosolic and nuclear NF-κB levels in time-dependent manners. Pretreatment with BAY 11-7082, an inhibitor of NF-κB activation, significantly inhibited LTA-induced SP-A mRNA expression. Sequentially, LTA time-dependently augmented phosphorylation of ERK1/2. In addition, levels of phosphorylated MEK1 were augmented following treatment with LTA. CONCLUSIONS Therefore, this study showed that LTA can increase SP-A synthesis in human alveolar type II epithelial cells through sequentially activating the MEK1-ERK1/2-NF-κB-dependent pathway.
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Affiliation(s)
- Feng-Lin Liu
- Department of Anesthesiology, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan
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Bacillus anthracis lethal toxin reduces human alveolar epithelial barrier function. Infect Immun 2012; 80:4374-87. [PMID: 23027535 DOI: 10.1128/iai.01011-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The lung is the site of entry for Bacillus anthracis in inhalation anthrax, the deadliest form of the disease. Bacillus anthracis produces virulence toxins required for disease. Alveolar macrophages were considered the primary target of the Bacillus anthracis virulence factor lethal toxin because lethal toxin inhibits mouse macrophages through cleavage of MEK signaling pathway components, but we have reported that human alveolar macrophages are not a target of lethal toxin. Our current results suggest that, unlike human alveolar macrophages, the cells lining the respiratory units of the lung, alveolar epithelial cells, are a target of lethal toxin in humans. Alveolar epithelial cells expressed lethal toxin receptor protein, bound the protective antigen component of lethal toxin, and were subject to lethal-toxin-induced cleavage of multiple MEKs. These findings suggest that human alveolar epithelial cells are a target of Bacillus anthracis lethal toxin. Further, no reduction in alveolar epithelial cell viability was observed, but lethal toxin caused actin rearrangement and impaired desmosome formation, consistent with impaired barrier function as well as reduced surfactant production. Therefore, by compromising epithelial barrier function, lethal toxin may play a role in the pathogenesis of inhalation anthrax by facilitating the dissemination of Bacillus anthracis from the lung in early disease and promoting edema in late stages of the illness.
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Andersson M, Lutay N, Hallgren O, Westergren-Thorsson G, Svensson M, Godaly G. Mycobacterium bovis bacilli Calmette-Guerin regulates leukocyte recruitment by modulating alveolar inflammatory responses. Innate Immun 2011; 18:531-40. [PMID: 22058091 PMCID: PMC3548393 DOI: 10.1177/1753425911426591] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Leukocyte migration into the epithelial compartment is an important feature in the active phase of mycobacterial infections. In this study, we used the Transwell model to investigate the mechanisms behind mycobacteria-induced leukocyte recruitment and investigated the role of TLR2 and TLR4 in this process. Infection of epithelial cells resulted in significantly increased secretion of the neutrophil chemotactic CXCL8 and IL-6, but no secretion of monocyte chemotactic CCL2 or TNF-α was observed. In contrast to epithelial response, mycobacteria-infected neutrophils and monocytes secreted all these cytokines. Corresponding with epithelial cytokine response, mycobacterial infection of the epithelial cells increased neutrophil diapedesis, but decreased monocyte recruitment. However, monocyte recruitment towards mycobacteria infected epithelial cells significantly increased following addition of neutrophil pre-conditioned medium. Mycobacterial infection also increases alveolar epithelial expression of TLR2, but not TLR4, as analyzed by flow cytometry, Western blotting and visualized by confocal microscopy. Blocking of TLR2 inhibited neutrophil recruitment and cytokine secretion, while blocking of TLR4 had a lesser effect. To summarize, we found that primary alveolar epithelial cells produced a selective TLR2-dependent cytokine secretion upon mycobacterial infection. Furthermore, we found that cooperation between cells of the innate immunity is required in mounting proper antimicrobial defence.
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Affiliation(s)
- Märta Andersson
- Department of Microbiology Immunology and Glycobiology, Division of Laboratory Medicine, Lund University, Lund, Sweden
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