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Benedetto R, Ousingsawat J, Wanitchakool P, Zhang Y, Holtzman MJ, Amaral M, Rock JR, Schreiber R, Kunzelmann K. Epithelial Chloride Transport by CFTR Requires TMEM16A. Sci Rep 2017; 7:12397. [PMID: 28963502 PMCID: PMC5622110 DOI: 10.1038/s41598-017-10910-0] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 08/16/2017] [Indexed: 12/15/2022] Open
Abstract
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is the secretory chloride/bicarbonate channel in airways and intestine that is activated through ATP binding and phosphorylation by protein kinase A, but fails to operate in cystic fibrosis (CF). TMEM16A (also known as anoctamin 1, ANO1) is thought to function as the Ca2+ activated secretory chloride channel independent of CFTR. Here we report that tissue specific knockout of the TMEM16A gene in mouse intestine and airways not only eliminates Ca2+-activated Cl− currents, but unexpectedly also abrogates CFTR-mediated Cl− secretion and completely abolishes cAMP-activated whole cell currents. The data demonstrate fundamentally new roles of TMEM16A in differentiated epithelial cells: TMEM16A provides a mechanism for enhanced ER Ca2+ store release, possibly engaging Store Operated cAMP Signaling (SOcAMPS) and activating Ca2+ regulated adenylyl cyclases. TMEM16A is shown to be essential for proper activation and membrane expression of CFTR. This intimate regulatory relationship is the cause for the functional overlap of CFTR and Ca2+-dependent chloride transport.
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Olias P, Etheridge RD, Zhang Y, Holtzman MJ, Sibley LD. Toxoplasma Effector Recruits the Mi-2/NuRD Complex to Repress STAT1 Transcription and Block IFN-γ-Dependent Gene Expression. Cell Host Microbe 2017; 20:72-82. [PMID: 27414498 DOI: 10.1016/j.chom.2016.06.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/09/2016] [Accepted: 06/09/2016] [Indexed: 12/12/2022]
Abstract
Interferon gamma (IFN-γ) is an essential mediator of host defense against intracellular pathogens, including the protozoan parasite Toxoplasma gondii. However, prior T. gondii infection blocks IFN-γ-dependent gene transcription, despite the downstream transcriptional activator STAT1 being activated and bound to cognate nuclear promoters. We identify the parasite effector that blocks STAT1-dependent transcription and show it is associated with recruitment of the Mi-2 nucleosome remodeling and deacetylase (NuRD) complex, a chromatin-modifying repressor. This secreted effector, toxoplasma inhibitor of STAT1-dependent transcription (TgIST), translocates to the host cell nucleus, where it recruits Mi-2/NuRD to STAT1-dependent promoters, resulting in altered chromatin and blocked transcription. TgIST is conserved across strains, underlying their shared ability to block IFN-γ-dependent transcription. TgIST deletion results in increased parasite clearance in IFN-γ-activated cells and reduced mouse virulence, which is restored in IFN-γ-receptor-deficient mice. These findings demonstrate the importance of both IFN-γ responses and the ability of pathogens to counteract these defenses.
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Woodruff PG, van den Berge M, Boucher RC, Brightling C, Burchard EG, Christenson SA, Han MK, Holtzman MJ, Kraft M, Lynch DA, Martinez FD, Reddel HK, Sin DD, Washko GR, Wenzel SE, Punturieri A, Freemer MM, Wise RA. American Thoracic Society/National Heart, Lung, and Blood Institute Asthma-Chronic Obstructive Pulmonary Disease Overlap Workshop Report. Am J Respir Crit Care Med 2017. [PMID: 28636425 DOI: 10.1164/rccm.201705-0973ws] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent chronic obstructive lung diseases with an associated high burden of disease. Asthma, which is often allergic in origin, frequently begins in infancy or childhood with variable airflow obstruction and intermittent wheezing, cough, and dyspnea. Patients with COPD, in contrast, are usually current or former smokers who present after the age of 40 years with symptoms (often persistent) including dyspnea and a productive cough. On the basis of age and smoking history, it is often easy to distinguish between asthma and COPD. However, some patients have features compatible with both diseases. Because clinical studies typically exclude these patients, their underlying disease mechanisms and appropriate treatment remain largely uncertain. To explore the status of and opportunities for research in this area, the NHLBI, in partnership with the American Thoracic Society, convened a workshop of investigators in San Francisco, California on May 14, 2016. At the workshop, current understanding of asthma-COPD overlap was discussed among clinicians, pathologists, radiologists, epidemiologists, and investigators with expertise in asthma and COPD. They considered knowledge gaps in our understanding of asthma-COPD overlap and identified strategies and research priorities that will advance its understanding. This report summarizes those discussions.
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Chatterjee S, Luthra P, Esaulova E, Agapov E, Yen BC, Borek DM, Edwards MR, Mittal A, Jordan DS, Ramanan P, Moore ML, Pappu RV, Holtzman MJ, Artyomov MN, Basler CF, Amarasinghe GK, Leung DW. Structural basis for human respiratory syncytial virus NS1-mediated modulation of host responses. Nat Microbiol 2017; 2:17101. [PMID: 28665409 DOI: 10.1038/nmicrobiol.2017.101] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 05/22/2017] [Indexed: 12/20/2022]
Abstract
Human respiratory syncytial virus (hRSV) is a major cause of morbidity and mortality in the paediatric, elderly and immune-compromised populations1,2. A gap in our understanding of hRSV disease pathology is the interplay between virally encoded immune antagonists and host components that limit hRSV replication. hRSV encodes for non-structural (NS) proteins that are important immune antagonists3-6; however, the role of these proteins in viral pathogenesis is incompletely understood. Here, we report the crystal structure of hRSV NS1 protein, which suggests that NS1 is a structural paralogue of hRSV matrix (M) protein. Comparative analysis of the shared structural fold with M revealed regions unique to NS1. Studies on NS1 wild type or mutant alone or in recombinant RSVs demonstrate that structural regions unique to NS1 contribute to modulation of host responses, including inhibition of type I interferon responses, suppression of dendritic cell maturation and promotion of inflammatory responses. Transcriptional profiles of A549 cells infected with recombinant RSVs show significant differences in multiple host pathways, suggesting that NS1 may have a greater role in regulating host responses than previously appreciated. These results provide a framework to target NS1 for therapeutic development to limit hRSV-associated morbidity and mortality.
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Liu Y, Gunsten SP, Sultan DH, Luehmann HP, Zhao Y, Blackwell TS, Bollermann-Nowlis Z, Pan JH, Byers DE, Atkinson JJ, Kreisel D, Holtzman MJ, Gropler RJ, Combadiere C, Brody SL. PET-based Imaging of Chemokine Receptor 2 in Experimental and Disease-related Lung Inflammation. Radiology 2017; 283:758-768. [PMID: 28045644 PMCID: PMC5452886 DOI: 10.1148/radiol.2016161409] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purpose To characterize a chemokine receptor type 2 (CCR2)-binding peptide adapted for use as a positron emission tomography (PET) radiotracer for noninvasive detection of lung inflammation in a mouse model of lung injury and in human tissues from subjects with lung disease. Materials and Methods The study was approved by institutional animal and human studies committees. Informed consent was obtained from patients. A 7-amino acid CCR2 binding peptide (extracellular loop 1 inverso [ECL1i]) was conjugated to tetraazacyclododecane tetraacetic acid (DOTA) and labeled with copper 64 (64Cu) or fluorescent dye. Lung inflammation was induced with intratracheal administration of lipopolysaccharide (LPS) in wild-type (n = 19) and CCR2-deficient (n = 4) mice, and these mice were compared with wild-type mice given control saline (n = 5) by using PET performed after intravenous injection of 64Cu-DOTA-ECL1i. Lung immune cells and those binding fluorescently labeled ECL1i in vivo were detected with flow cytometry. Lung inflammation in tissue from subjects with nondiseased lungs donated for lung transplantation (n = 11) and those with chronic obstructive pulmonary disease (COPD) who were undergoing lung transplantation (n = 16) was evaluated for CCR2 with immunostaining and autoradiography (n = 6, COPD) with 64Cu-DOTA-ECL1i. Groups were compared with analysis of variance, the Mann-Whitney U test, or the t test. Results Signal on PET images obtained in mouse lungs after injury with LPS was significantly greater than that in the saline control group (mean = 4.43% of injected dose [ID] per gram of tissue vs 0.99% of injected dose per gram of tissue; P < .001). PET signal was significantly diminished with blocking studies using nonradiolabeled ECL1i in excess (mean = 0.63% ID per gram of tissue; P < .001) and in CCR2-deficient mice (mean = 0.39% ID per gram of tissue; P < .001). The ECL1i signal was associated with an elevated level of mouse lung monocytes. COPD lung tissue displayed significantly elevated CCR2 levels compared with nondiseased tissue (median = 12.8% vs 1.2% cells per sample; P = .002), which was detected with 64Cu-DOTA-ECL1i by using autoradiography. Conclusion 64Cu-DOTA-ECL1i is a promising tool for PET-based detection of CCR2-directed inflammation in an animal model and in human tissues as a step toward clinical translation. © RSNA, 2017 Online supplemental material is available for this article.
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Murthy AK, Manam S, La Salle S, Holtzman MJ, Zhang Y, Ramsey KH, Nicholson BJ. Gap Junction Mediated Antigen Transport in Epithelium Promotes Amplification of CD8 T Cell Mediated Bystander Pathology Following Chlamydial Infection. THE JOURNAL OF IMMUNOLOGY 2017. [DOI: 10.4049/jimmunol.198.supp.149.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Chlamydia-specific CD8 T cells play a significant role in oviduct pathology, not bacterial clearance. We hypothesized that gap junction mediated antigen transport (GMAT) from infected to uninfected cells could explain the apparent targeting of uninfected epithelial cells by Chlamydia-specific CD8 T cells. Since gap junction protein connexin 43 is highly expressed in oviduct epithelium, we generated Foxj1Cre-Cx43flox mice with a conditional deficiency of CX43 only in ciliated columnar epithelia in oviducts. Foxj1Cre-Cx43flox mice displayed similar chlamydial infection, but reduced splenic Ag-specific CD8 T cell response and oviduct pathology when compared to WT mice, suggesting that CX43-mediates chlamydial pathogenesis. To evaluate the role of GMAT via CX43 in pathogenesis, HeLa S3 cells were engineered to express functional CX43 or a closed channel point-mutant CX43 (T154A). Chlamydial peptides were observed in neighboring uninfected cells at mid-developmental cycle upon infection of HeLa-CX43, not HeLa S3 or HeLa-CX43-T154A cells. Naïve mouse antigen-presenting cells (APC) optimally activated Chlamydia-specific mouse CD8 T cells upon co-culture with Chlamydia-infected HeLa-CX43, when compared to HeLa S3 or HeLa-CX43-T154A cells, demonstrating that GMAT is involved in activation of CD8 T cells. Furthermore, naïve mouse APC optimally activated Chlamydia-specific mouse CD8 T cells upon co-culture with a 1:4 mixture of Chlamydia-infected HeLa-CX43 and uninfected HeLa-CX43 cells, when compared to mixtures of infected HeLa-CX43 with uninfected HeLa-S3 or HeLa-CX43-T154A cells. These results demonstrate that GMAT via uninfected epithelial cells amplifies pathogenic Chlamydia-specific CD8 T cell response.
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Li S, O'Neill SRS, Zhang Y, Holtzman MJ, Takemaru KI, Korach KS, Winuthayanon W. Estrogen receptor α is required for oviductal transport of embryos. FASEB J 2017; 31:1595-1607. [PMID: 28082352 DOI: 10.1096/fj.201601128r] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/19/2016] [Indexed: 01/14/2023]
Abstract
Newly fertilized embryos spend the first few days within the oviduct and are transported to the uterus, where they implant onto the uterine wall. An implantation of the embryo before reaching the uterus could result in ectopic pregnancy and lead to maternal death. Estrogen is necessary for embryo transport in mammals; however, the mechanism involved in estrogen-mediated cellular function within the oviduct remains unclear. In this study, we show in mouse models that ciliary length and beat frequency of the oviductal epithelial cells are regulated through estrogen receptor α (ESR1) but not estrogen receptor β (ESR2). Gene profiling indicated that transcripts in the WNT/β-catenin (WNT/CTNNB1) signaling pathway were regulated by estrogen in mouse oviduct, and inhibition of this pathway in a whole oviduct culture system resulted in a decreased embryo transport distance. However, selective ablation of CTNNB1 from the oviductal ciliated cells did not affect embryo transport, possibly because of a compensatory mechanism via intact CTNNB1 in the adjacent secretory cells. In summary, we demonstrated that disruption of estrogen signaling in oviductal epithelial cells alters ciliary function and impairs embryo transport. Therefore, our findings may provide a better understanding of etiology of the ectopic pregnancy that is associated with alteration of estrogen signals.-Li, S., O'Neill, S. R. S., Zhang, Y., Holtzman, M. J., Takemaru, K.-I., Korach, K. S., Winuthayanon, W. Estrogen receptor α is required for oviductal transport of embryos.
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Kober DL, Alexander-Brett JM, Karch CM, Cruchaga C, Colonna M, Holtzman MJ, Brett TJ. Neurodegenerative disease mutations in TREM2 reveal a functional surface and distinct loss-of-function mechanisms. eLife 2016; 5:e20391. [PMID: 27995897 PMCID: PMC5173322 DOI: 10.7554/elife.20391] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/28/2016] [Indexed: 01/09/2023] Open
Abstract
Genetic variations in the myeloid immune receptor TREM2 are linked to several neurodegenerative diseases. To determine how TREM2 variants contribute to these diseases, we performed structural and functional studies of wild-type and variant proteins. Our 3.1 Å TREM2 crystal structure revealed that mutations found in Nasu-Hakola disease are buried whereas Alzheimer's disease risk variants are found on the surface, suggesting that these mutations have distinct effects on TREM2 function. Biophysical and cellular methods indicate that Nasu-Hakola mutations impact protein stability and decrease folded TREM2 surface expression, whereas Alzheimer's risk variants impact binding to a TREM2 ligand. Additionally, the Alzheimer's risk variants appear to epitope map a functional surface on TREM2 that is unique within the larger TREM family. These findings provide a guide to structural and functional differences among genetic variants of TREM2, indicating that therapies targeting the TREM2 pathway should be tailored to these genetic and functional differences with patient-specific medicine approaches for neurodegenerative disorders.
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Vindedal GF, Thoren AE, Jensen V, Klungland A, Zhang Y, Holtzman MJ, Ottersen OP, Nagelhus EA. Removal of aquaporin-4 from glial and ependymal membranes causes brain water accumulation. Mol Cell Neurosci 2016; 77:47-52. [PMID: 27751903 DOI: 10.1016/j.mcn.2016.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 10/04/2016] [Accepted: 10/13/2016] [Indexed: 12/13/2022] Open
Abstract
There is a constitutive production of water in brain. The efflux routes of this excess water remain to be identified. We used basal brain water content as a proxy for the capacity of water exit routes. Basal brain water content was increased in mice with a complete loss of aquaporin-4 (AQP4) water channels (global Aqp4-/- mice), but not in mice with a selective removal of perivascular AQP4 or in a novel mouse line with a selective deletion of ependymal AQP4 (Foxj1-Cre:Aqp4flox/flox mice). Unique for the global Aqp4-/- mice is the loss of the AQP4 pool subjacent to the pial membrane. Our data suggest that water accumulates in brain when subpial AQP4 is missing, pointing to a critical role of this pool of water channels in brain water exit.
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Yurtsever Z, Patel DA, Kober DL, Su A, Miller CA, Romero AG, Holtzman MJ, Brett TJ. First comprehensive structural and biophysical analysis of MAPK13 inhibitors targeting DFG-in and DFG-out binding modes. Biochim Biophys Acta Gen Subj 2016; 1860:2335-2344. [PMID: 27369736 DOI: 10.1016/j.bbagen.2016.06.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/13/2016] [Accepted: 06/26/2016] [Indexed: 12/24/2022]
Abstract
BACKGROUND P38 MAP kinases are centrally involved in mediating extracellular signaling in various diseases. While much attention has previously been focused on the ubiquitously expressed family member MAPK14 (p38α), recent studies indicate that family members such as MAPK13 (p38δ) display a more selective cellular and tissue expression and might therefore represent a specific kinase to target in certain diseases. METHODS To facilitate the design of potent and specific inhibitors, we present here the structural, biophysical, and functional characterization of two new MAPK13-inhibitor complexes, as well as the first comprehensive structural, biophysical, and functional analysis of MAPK13 complexes with four different inhibitor compounds of greatly varying potency. RESULTS These inhibitors display IC50 values either in the nanomolar range or micromolar range (>800-fold range). The nanomolar inhibitors exhibit much longer ligand-enzyme complex half-lives compared to the micromolar inhibitors as measured by biolayer interferometry. Crystal structures of the MAPK13 inhibitor complexes reveal that the nanomolar inhibitors engage MAPK13 in the DFG-out binding mode, while the micromolar inhibitors are in the DFG-in mode. Detailed structural and computational docking analyses suggest that this difference in binding mode engagement is driven by conformational restraints imposed by the chemical structure of the inhibitors, and may be fortified by an additional hydrogen bond to MAPK13 in the nanomolar inhibitors. CONCLUSIONS These studies provide a structural basis for understanding the differences in potency exhibited by these inhibitors. GENERAL SIGNIFICANCE They also provide the groundwork for future studies to improve specificity, potency, pharmacodynamics, and pharmacokinetic properties.
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Lu Q, Yokoyama CC, Williams JW, Baldridge MT, Jin X, DesRochers B, Bricker T, Wilen CB, Bagaitkar J, Loginicheva E, Sergushichev A, Kreamalmeyer D, Keller BC, Zhao Y, Kambal A, Green DR, Martinez J, Dinauer MC, Holtzman MJ, Crouch EC, Beatty W, Boon ACM, Zhang H, Randolph GJ, Artyomov MN, Virgin HW. Homeostatic Control of Innate Lung Inflammation by Vici Syndrome Gene Epg5 and Additional Autophagy Genes Promotes Influenza Pathogenesis. Cell Host Microbe 2016; 19:102-13. [PMID: 26764600 PMCID: PMC4714358 DOI: 10.1016/j.chom.2015.12.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/11/2015] [Accepted: 12/18/2015] [Indexed: 12/21/2022]
Abstract
Mutations in the autophagy gene EPG5 are linked to the multisystem human disease Vici syndrome, which is characterized in part by pulmonary abnormalities, including recurrent infections. We found that Epg5-deficient mice exhibited elevated baseline innate immune cellular and cytokine-based lung inflammation and were resistant to lethal influenza virus infection. Lung transcriptomics, bone marrow transplantation experiments, and analysis of cellular cytokine expression indicated that Epg5 plays a role in lung physiology through its function in macrophages. Deletion of other autophagy genes including Atg14, Fip200, Atg5, and Atg7 in myeloid cells also led to elevated basal lung inflammation and influenza resistance. This suggests that Epg5 and other Atg genes function in macrophages to limit innate immune inflammation in the lung. Disruption of this normal homeostatic dampening of lung inflammation results in increased resistance to influenza, suggesting that normal homeostatic mechanisms that limit basal tissue inflammation support some infectious diseases.
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Kim HJ, Kim CH, Kim MJ, Ryu JH, Seong SY, Kim S, Lim SJ, Holtzman MJ, Yoon JH. The Induction of Pattern-Recognition Receptor Expression against Influenza A Virus through Duox2-Derived Reactive Oxygen Species in Nasal Mucosa. Am J Respir Cell Mol Biol 2015; 53:525-35. [PMID: 25751630 DOI: 10.1165/rcmb.2014-0334oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We studied the relative roles of Duox2-derived reactive oxygen species (ROS) in host defense against influenza A virus (IAV) infection in normal human nasal epithelial cells and mouse nasal mucosa. We found that Duox2 primarily generated ROS rapidly after IAV infection in normal human nasal epithelial cells and that knockdown of Duox2 aggravated IAV infection. In addition, Duox2-derived ROS enhancement significantly suppressed IAV infection in nasal epithelium. In particular, Duox2-derived ROS were required for the induction of retinoic acid-inducible gene (RIG)-I and melanoma differentiation-associated protein 5 (MDA5) transcription. After intranasal IAV inoculation into mice, viral infection was significantly aggravated from 3 days postinoculation (dpi) in the nasal mucosa, and the IAV viral titer was highest at 7 dpi. Both RIG-I and MDA5 messenger RNA levels increased dominantly in mouse nasal mucosa from 3 dpi; consistent with this, RIG-I and MDA5 proteins were also induced after IAV infection. RIG-I and MDA5 messenger RNA levels were induced to a lower extent in the nasal mucosa of the mice that were inoculated with Duox2 short hairpin RNA, and the IAV viral titer was significantly higher in nasal lavage. Taken together, Duox2-derived ROS are necessary for the innate immune response and trigger the induction of RIG-I and MDA5 to resist IAV infection in human nasal epithelium and mouse nasal mucosa.
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Zhang Y, Mao D, Roswit WT, Jin X, Patel AC, Patel DA, Agapov E, Wang Z, Tidwell RM, Atkinson JJ, Huang G, McCarthy R, Yu J, Yun NE, Paessler S, Lawson TG, Omattage NS, Brett TJ, Holtzman MJ. PARP9-DTX3L ubiquitin ligase targets host histone H2BJ and viral 3C protease to enhance interferon signaling and control viral infection. Nat Immunol 2015; 16:1215-27. [PMID: 26479788 PMCID: PMC4653074 DOI: 10.1038/ni.3279] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/26/2015] [Indexed: 12/12/2022]
Abstract
Enhancing the response to interferon could offer an immunological advantage to the host. In support of this concept, we used a modified form of the transcription factor STAT1 to achieve hyper-responsiveness to interferon without toxicity and markedly improve antiviral function in transgenic mice and transduced human cells. We found that the improvement depended on expression of a PARP9-DTX3L complex with distinct domains for interaction with STAT1 and for activity as an E3 ubiquitin ligase that acted on host histone H2BJ to promote interferon-stimulated gene expression and on viral 3C proteases to degrade these proteases via the immunoproteasome. Thus, PARP9-DTX3L acted on host and pathogen to achieve a double layer of immunity within a safe reserve in the interferon signaling pathway.
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Pan JH, Adair-Kirk TL, Patel AC, Huang T, Yozamp NS, Xu J, Reddy EP, Byers DE, Pierce RA, Holtzman MJ, Brody SL. Myb permits multilineage airway epithelial cell differentiation. Stem Cells 2015; 32:3245-56. [PMID: 25103188 DOI: 10.1002/stem.1814] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 07/14/2014] [Indexed: 12/12/2022]
Abstract
The epithelium of the pulmonary airway is specially differentiated to provide defense against environmental insults, but also subject to dysregulated differentiation that results in lung disease. The current paradigm for airway epithelial differentiation is a one-step program whereby a p63(+) basal epithelial progenitor cell generates a ciliated or secretory cell lineage, but the cue for this transition and whether there are intermediate steps are poorly defined. Here, we identify transcription factor Myb as a key regulator that permits early multilineage differentiation of airway epithelial cells. Myb(+) cells were identified as p63(-) and therefore distinct from basal progenitor cells, but were still negative for markers of differentiation. Myb RNAi treatment of primary-culture airway epithelial cells and Myb gene deletion in mice resulted in a p63(-) population with failed maturation of Foxj1(+) ciliated cells as well as Scbg1a1(+) and Muc5ac(+) secretory cells. Consistent with these findings, analysis of whole genome expression of Myb-deficient cells identified Myb-dependent programs for ciliated and secretory cell differentiation. Myb(+) cells were rare in human airways but were increased in regions of ciliated cells and mucous cell hyperplasia in samples from subjects with chronic obstructive pulmonary disease. Together, the results show that a p63(-) Myb(+) population of airway epithelial cells represents a distinct intermediate stage of differentiation that is required under normal conditions and may be heightened in airway disease.
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Chen J, Zhao J, Chen L, Dong N, Ying Z, Cai Z, Ji D, Zhang Y, Dong L, Li Y, Jiang L, Holtzman MJ, Chen C. STAT1 modification improves therapeutic effects of interferons on lung cancer cells. J Transl Med 2015; 13:293. [PMID: 26351076 PMCID: PMC4562290 DOI: 10.1186/s12967-015-0656-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 08/28/2015] [Indexed: 12/20/2022] Open
Abstract
Background Interferons (IFNs) have potent anti-proliferative, pro-apoptotic, and immunomodulatory activities against cancer. However, the clinical utility of IFNs is limited by toxicity and pharmacokinetics making it difficult to achieve sustained therapeutic levels especially in solid tumors. Methods Signal Transducer and Activator of Transcription 1 (STAT1) or a modified STAT1 (designated STAT1-CC) that is hyper-responsive to IFN were overexpressed in lung cancer SPC-A-1 and H1299 cells using lentiviral vectors. Transduction efficiency was monitored using enhanced green fluorescent protein (EGFP) expression. After transduction, cells were treated with interferon-gamma (IFN-γ) or interferon-beta (IFN-β) and monitored for cell proliferation, migration, and invasiveness using Cell Counting Kit-8 and transwell chamber assays and for apoptosis using Annexin V detection by flow cytometry. In addition, levels of STAT1, STAT1 Tyr-701 phosphorylation (pSTAT1), fibronectin, and β-catenin were determined using western blotting. In the case of IFN-γ stimulation, levels of S100A4, proliferating cell nuclear antigen (PCNA), and c-fos expression were also determined. Results We found that expression of STAT1 or STAT1-CC enhanced the effect of IFN-γ and, IFN-β on inhibition of human lung cancer cell proliferation, migration and invasiveness. Moreover, STAT1 and STAT1-CC expression caused increases in pSTAT1 and decreases in fibronectin and β-catenin levels. STAT1-CC showed increased effects compared to STAT1 on IFN-γ induced pSTAT1 and down-regulation of S100A4, PCNA, and c-fos levels. Conclusion The results show that STAT1-CC exhibited more strength in improving the antitumor response of IFNs in lung cancer cells. Results from this study suggest that combined treatment of IFNs and STAT1-CC might be a feasible approach for the clinical management of lung cancer in the future.
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Huang PH, Ren L, Nama N, Li S, Li P, Yao X, Cuento RA, Wei CH, Chen Y, Xie Y, Nawaz AA, Alevy YG, Holtzman MJ, McCoy JP, Levine SJ, Huang TJ. An acoustofluidic sputum liquefier. LAB ON A CHIP 2015; 15:3125-31. [PMID: 26082346 PMCID: PMC6518399 DOI: 10.1039/c5lc00539f] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We demonstrate the first microfluidic-based on-chip liquefaction device for human sputum samples. Our device is based on an acoustofluidic micromixer using oscillating sharp edges. This acoustofluidic sputum liquefier can effectively and uniformly liquefy sputum samples at a throughput of 30 μL min(-1). Cell viability and integrity are maintained during the sputum liquefaction process. Our acoustofluidic sputum liquefier can be conveniently integrated with other microfluidic units to enable automated on-chip sputum processing and analysis.
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Dickinson JD, Alevy Y, Malvin NP, Patel KK, Gunsten SP, Holtzman MJ, Stappenbeck TS, Brody SL. IL13 activates autophagy to regulate secretion in airway epithelial cells. Autophagy 2015; 12:397-409. [PMID: 26062017 DOI: 10.1080/15548627.2015.1056967] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Cytokine modulation of autophagy is increasingly recognized in disease pathogenesis, and current concepts suggest that type 1 cytokines activate autophagy, whereas type 2 cytokines are inhibitory. However, this paradigm derives primarily from studies of immune cells and is poorly characterized in tissue cells, including sentinel epithelial cells that regulate the immune response. In particular, the type 2 cytokine IL13 (interleukin 13) drives the formation of airway goblet cells that secrete excess mucus as a characteristic feature of airway disease, but whether this process is influenced by autophagy was undefined. Here we use a mouse model of airway disease in which IL33 (interleukin 33) stimulation leads to IL13-dependent formation of airway goblet cells as tracked by levels of mucin MUC5AC (mucin 5AC, oligomeric mucus/gel forming), and we show that these cells manifest a block in mucus secretion in autophagy gene Atg16l1-deficient mice compared to wild-type control mice. Similarly, primary-culture human tracheal epithelial cells treated with IL13 to stimulate mucus formation also exhibit a block in MUC5AC secretion in cells depleted of autophagy gene ATG5 (autophagy-related 5) or ATG14 (autophagy-related 14) compared to nondepleted control cells. Our findings indicate that autophagy is essential for airway mucus secretion in a type 2, IL13-dependent immune disease process and thereby provide a novel therapeutic strategy for attenuating airway obstruction in hypersecretory inflammatory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis lung disease. Taken together, these observations suggest that the regulation of autophagy by Th2 cytokines is cell-context dependent.
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Wu K, Byers DE, Jin X, Agapov E, Alexander-Brett J, Patel AC, Cella M, Gilfilan S, Colonna M, Kober DL, Brett TJ, Holtzman MJ. TREM-2 promotes macrophage survival and lung disease after respiratory viral infection. ACTA ACUST UNITED AC 2015; 212:681-97. [PMID: 25897174 PMCID: PMC4419356 DOI: 10.1084/jem.20141732] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 03/20/2015] [Indexed: 01/04/2023]
Abstract
Wu et al. use a mouse model to show that active respiratory viral infection triggers TREM-2 expression on the macrophage cell surface and thereby prevents macrophage apoptosis during the acute illness. In addition, long after viral clearance, IL-13 and DAP12 promote TREM-2 cleavage to its soluble form that unexpectedly also enhances macrophage survival and promotes chronic inflammatory disease. Viral infections and type 2 immune responses are thought to be critical for the development of chronic respiratory disease, but the link between these events needs to be better defined. Here, we study a mouse model in which infection with a mouse parainfluenza virus known as Sendai virus (SeV) leads to long-term activation of innate immune cells that drive IL-13–dependent lung disease. We find that chronic postviral disease (signified by formation of excess airway mucus and accumulation of M2-differentiating lung macrophages) requires macrophage expression of triggering receptor expressed on myeloid cells-2 (TREM-2). Analysis of mechanism shows that viral replication increases lung macrophage levels of intracellular and cell surface TREM-2, and this action prevents macrophage apoptosis that would otherwise occur during the acute illness (5–12 d after inoculation). However, the largest increases in TREM-2 levels are found as the soluble form (sTREM-2) long after clearance of infection (49 d after inoculation). At this time, IL-13 and the adapter protein DAP12 promote TREM-2 cleavage to sTREM-2 that is unexpectedly active in preventing macrophage apoptosis. The results thereby define an unprecedented mechanism for a feed-forward expansion of lung macrophages (with IL-13 production and consequent M2 differentiation) that further explains how acute infection leads to chronic inflammatory disease.
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Yurtsever Z, Scheaffer SM, Romero AG, Holtzman MJ, Brett TJ. The crystal structure of phosphorylated MAPK13 reveals common structural features and differences in p38 MAPK family activation. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:790-9. [PMID: 25849390 PMCID: PMC4388263 DOI: 10.1107/s1399004715001212] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/20/2015] [Indexed: 11/10/2022]
Abstract
The p38 MAP kinases (p38 MAPKs) represent an important family centrally involved in mediating extracellular signaling. Recent studies indicate that family members such as MAPK13 (p38δ) display a selective cellular and tissue expression and are therefore involved in specific diseases. Detailed structural studies of all p38 MAPK family members are crucial for the design of specific inhibitors. In order to facilitate such ventures, the structure of MAPK13 was determined in both the inactive (unphosphorylated; MAPK13) and active (dual phosphorylated; MAPK13/pTpY) forms. Here, the first preparation, crystallization and structure determination of MAPK13/pTpY are presented and the structure is compared with the previously reported structure of MAPK13 in order to facilitate studies for structure-based drug design. A comprehensive analysis of inactive versus active structures for the p38 MAPK family is also presented. It is found that MAPK13 undergoes a larger interlobe configurational rearrangement upon activation compared with MAPK14. Surprisingly, the analysis of activated p38 MAPK structures (MAP12/pTpY, MAPK13/pTpY and MAPK14/pTpY) reveals that, despite a high degree of sequence similarity, different side chains are used to coordinate the phosphorylated residues. There are also differences in the rearrangement of the hinge region that occur in MAPK14 compared with MAPK13 which would affect inhibitor binding. A thorough examination of all of the active (phosphorylated) and inactive (unphosphorylated) p38 MAPK family member structures was performed to reveal a common structural basis of activation for the p38 MAP kinase family and to identify structural differences that may be exploited for developing family member-specific inhibitors.
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Barrow AD, Palarasah Y, Bugatti M, Holehouse AS, Byers DE, Holtzman MJ, Vermi W, Skjødt K, Crouch E, Colonna M. OSCAR is a receptor for surfactant protein D that activates TNF-α release from human CCR2+ inflammatory monocytes. THE JOURNAL OF IMMUNOLOGY 2015; 194:3317-26. [PMID: 25716998 DOI: 10.4049/jimmunol.1402289] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Surfactant protein D (SP-D) is critical for maintenance of lung homeostasis and provides a first line of defense to pathogens at mucosal surfaces. Polymorphisms in the SP-D-encoding gene SFTPD have been associated with chronic obstructive pulmonary disease and ulcerative colitis. Identification of the immunoreceptors that bind SP-D is essential for understanding its contribution to lung homeostasis and mucosal defense. We located a putative binding motif for the osteoclast-associated receptor (OSCAR) within the SP-D collagenous domain. An OSCAR-Fc fusion protein specifically bound to the collagenous region of recombinant SP-D and captured native SP-D from human bronchoalveolar lavage. OSCAR localized in an intracellular compartment of alveolar macrophages together with SP-D. Moreover, we found OSCAR on the surface of interstitial lung and blood CCR2(+) inflammatory monocytes, which secreted TNF-α when exposed to SP-D in an OSCAR-dependent fashion. OSCAR and SP-D did not exclusively colocalize in lung, as they were also highly expressed in atherosclerotic plaques of human aorta, supporting a role for this interaction in atherosclerosis. Our results identify the OSCAR:SP-D interaction as a potential therapeutic target in chronic inflammatory diseases of the lung as well as other diseases involving tissue accumulation of SP-D, infiltration of inflammatory monocytes, and release of TNF-α.
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Abstract
The airway epithelial cell barrier serves as the main site of replication for most of the common respiratory viruses and is thereby the first line of defense against these viruses. Host epithelial cells are specially enriched for pattern recognition receptors that activate immune response genes to limit viral replication. A prominently expressed set of these genes encodes cytokines that orchestrate key aspects of host defense, such as recruitment of immune cells and repair of epithelial cell damage. Under some circumstances, airway epithelial cells may be programmed to release cytokines (notably IL-33) that activate a type 2 immune response, which in excess might contribute to the development of chronic obstructive lung disease. Moreover, long-term epithelial progenitor cells with this capability may explain an ongoing susceptibility to lung disease in response to acute respiratory infection or other types of inhaled danger signals. The mucosal airway epithelial cell can thereby mediate a beneficial response for host defense and a detrimental response leading to inflammatory disease.
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Abadie V, Abraham C, Adams DH, Agace WW, Alexander-Brett J, Alkhairy O, Ambite I, Anderson DJ, Artis D, Atmar RL, Aymeric L, Bachert C, Bakema JE, Baker K, Beagley KW, Befus A, Bemark M, Berin MC, Berings M, Berzofsky JA, Bilej M, Biswas N, Blumberg RS, Bienenstock J, Bogdanos D, Boirivant M, Boonnak K, Bracke KR, Brandtzaeg P, Braun J, Bringer MA, Broadbent AJ, Bronson R, Brusselle GG, Bulmer JN, Butler J, Cardenas PA, Cebra JJ, Cella M, Cerutti A, Challacombe SJ, Chattha K, Cheroutre H, Chiba T, Chorny A, Clements JD, Colonna M, Cookson WO, Corbeil LB, Corthésy B, Cripps AW, van Crombruggen K, Pires da Cunha A, Cunningham-Rundles S, Curtiss R, Darfeuille-Michaud A, de Jonge WJ, Deban L, Denning TL, Di Santo JP, Diefenbach A, DiRita VJ, Downey J, Du MQ, Edelblum KL, van Egmond M, Epple HJ, Fagarasan S, Fahey JV, Ferris MJ, Fichtner-Feigl S, Fidel PL, Flach M, Flavell R, Fleit HB, Franchini G, Freytag LC, Fuchs A, Fujihashi K, Fuss IJ, Gagliani N, Garcia MR, Garrett WS, Gershwin ME, Gevaert P, Gleeson M, Godaly G, Goldblum RM, Gour N, Gursel M, Hajishengallis G, Hammad H, Hammarström L, Hänninen A, Hanson LÅ, Hayday A, Herzog R, Hodgins DC, Holgate ST, Holmgren J, Holtzman MJ, Hook EW, Huber S, Hurwitz JL, Ivanyi J, Iwasaki A, Jabri B, Jackson S, Jacobs J, Jalkanen S, Janoff EN, Jerse AE, Jeyanathan M, Julian BA, Kacskovics I, Kaetzel CS, Kaushic C, Kelsall BL, Kessans S, Kesselring R, Kilian M, Kiyono H, Klinman DM, Korotkova M, Kronenberg M, Krysko O, Kurono Y, Kverka M, Lambrecht BN, Lamm ME, Lantz O, Lash GE, Lavelle E, Lefrancois L, Leung PS, Levine MM, Lim DJ, Lippolis J, Louis NA, Luster AD, Lutay N, Lycke N, Macpherson AJ, Mantis NJ, Marcotte H, Martin DH, Mason HS, Massa HM, Matoba N, Mayer L, Maynard CL, McElrath MJ, McEntee C, McGhee JR, McGuckin MA, Mestecky J, Mikhak Z, Miller RD, Moldoveanu Z, Montgomery PC, Mor T, Neurath MF, Neyt K, Nicholson LK, Novak J, Nowicki S, O’Hagan D, O’Sullivan NL, Ogra P, Orihuela C, Ouellette AJ, Owen RL, Pabst O, Parkos CA, Parreño V, Patel MV, Perez-Novo C, Perkins DJ, Prussin C, Pudney J, Raghavan S, Rainard P, Ramani S, Randall TD, Raska M, Renukaradhya GJ, Rescigno M, Rosenthal KL, Rothenberg ME, Ruemmele FM, Russell MW, Saif LJ, Salinas I, Salmi M, Salmon H, Sampson HA, Sansonetti P, Schneider T, Serafini N, Sharma D, Shen Z, Shi HN, Shirlaw PJ, Shivhare SB, Smith PD, Smith PM, Smith DJ, Smythies LE, Spencer J, Strober W, Subbarao K, Svanborg C, Svennerholm AM, Taubman MA, Telemo E, Thornhill MH, Thornton DJ, Thuenemann E, Tlaskalova-Hogenova H, Tristram D, Trivedi P, Tuomanen E, Turanek J, Turner JR, Underdown BJ, van Helden MJ, Veazey RS, Verdu EF, Vlasova A, Vliagoftis H, Vogel SN, Walker WA, Wang X, Watanabe T, Weaver CT, Weiner HL, Wells JM, Wen T, Whittum-Hudson J, Whitsett JA, Williams IR, Wills-Karp M, Wira CR, Woof JM, Wotherspoon AC, Xing Z, Xu H, Zaph C, Zeissig S, Zeitz M. Contributors. Mucosal Immunol 2015. [DOI: 10.1016/b978-0-12-415847-4.01002-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Patel DA, You Y, Huang G, Byers DE, Kim HJ, Agapov E, Moore ML, Peebles RS, Castro M, Sumino K, Shifren A, Brody SL, Holtzman MJ. Interferon response and respiratory virus control are preserved in bronchial epithelial cells in asthma. J Allergy Clin Immunol 2014; 134:1402-1412.e7. [PMID: 25216987 PMCID: PMC4261010 DOI: 10.1016/j.jaci.2014.07.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 06/06/2014] [Accepted: 07/02/2014] [Indexed: 12/27/2022]
Abstract
BACKGROUND Some investigators find a deficiency in IFN production from airway epithelial cells infected with human rhinovirus in asthma, but whether this abnormality occurs with other respiratory viruses is uncertain. OBJECTIVE To assess the effect of influenza A virus (IAV) and respiratory syncytial virus (RSV) infection on IFN production and viral level in human bronchial epithelial cells (hBECs) from subjects with and without asthma. METHODS Primary-culture hBECs from subjects with mild to severe asthma (n = 11) and controls without asthma (hBECs; n = 7) were infected with live or ultraviolet-inactivated IAV (WS/33 strain), RSV (Long strain), or RSV (A/2001/2-20 strain) with multiplicity of infection 0.01 to 1. Levels of virus along with IFN-β and IFN-λ and IFN-stimulated gene expression (tracked by 2'-5'-oligoadenylate synthetase 1 and myxovirus (influenza virus) resistance 1 mRNA) were determined up to 72 hours postinoculation. RESULTS After IAV infection, viral levels were increased 2-fold in hBECs from asthmatic subjects compared with nonasthmatic control subjects (P < .05) and this increase occurred in concert with increased IFN-λ1 levels and no significant difference in IFNB1, 2'-5'-oligoadenylate synthetase 1, or myxovirus (influenza virus) resistance 1mRNA levels. After RSV infections, viral levels were not significantly increased in hBECs from asthmatic versus nonasthmatic subjects and the only significant difference between groups was a decrease in IFN-λ levels (P < .05) that correlated with a decrease in viral titer. All these differences were found only at isolated time points and were not sustained throughout the 72-hour infection period. CONCLUSIONS The results indicate that IAV and RSV control and IFN response to these viruses in airway epithelial cells is remarkably similar between subjects with and without asthma.
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Holtzman MJ, Byers DE, Alexander-Brett J, Wang X. The role of airway epithelial cells and innate immune cells in chronic respiratory disease. Nat Rev Immunol 2014; 14:686-98. [PMID: 25234144 PMCID: PMC4782595 DOI: 10.1038/nri3739] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An abnormal immune response to environmental agents is generally thought to be responsible for causing chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Based on studies of experimental models and human subjects, there is increasing evidence that the response of the innate immune system is crucial for the development of this type of airway disease. Airway epithelial cells and innate immune cells represent key components of the pathogenesis of chronic airway disease and are emerging targets for new therapies. In this Review, we summarize the innate immune mechanisms by which airway epithelial cells and innate immune cells regulate the development of chronic respiratory diseases. We also explain how these pathways are being targeted in the clinic to treat patients with these diseases.
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Ebbinghaus M, Gajda M, Holtzman MJ, Schulz S, Schaible HG. Does chloride channel accessory 3 have a role in arthritis pain? A study on murine antigen-induced arthritis. Neurosci Lett 2014; 576:40-4. [PMID: 24905173 DOI: 10.1016/j.neulet.2014.05.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 12/18/2022]
Abstract
Calcium-activated chloride channels (CaCCs) are thought to regulate neuronal excitability, and recently chloride (Cl(-)) regulation in DRG neurons has attracted much attention in pain research. Furthermore, the activity of CaCCs is modified by a family of CLCA proteins. In acute antigen-induced arthritis (AIA), a remarkable up-regulation of the murine chloride channel accessory 3 (mClca3) was shown in dorsal root ganglion (DRG) neurons. Therefore we tested the hypothesis that mClca3 is involved in arthritic pain perception. In mClca3 knock-out mice and wild-type control mice, AIA was induced and measures of inflammation and pain were assessed. In the very acute phase of AIA, joint swelling was reduced in mClca3 knock-out mice. This effect disappeared during the course of AIA. We could not show significant differences in mechanical hyperalgesia between both groups of mice, neither at the acute nor at the chronic stage (21 days of AIA). Additional experiments on thermal hyperalgesia in wild-type and mClca3 knock-out mice in the first 3 days of AIA did not show a difference either. In addition, niflumic acid, an antagonist at CaCCs, did not significantly influence hyperalgesia during AIA. Thus, we were not able to provide evidence for a role of CaCCs, and in particular of mClca3, on the expression of arthritis or inflammation-evoked hyperalgesia.
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