title: Toll-like Receptor 7 Is Reduced in Severe Asthma and Linked to an Altered MicroRNA Profile.
abstract: Asthma is one of the most common chronic diseases worldwide, and individuals with severe asthma experience recurrent exacerbations. Exacerbations are predominantly viral associated and have been linked to defective airway IFN responses. Ascertaining the molecular mechanisms underlying this deficiency is a major research goal to identify new therapeutic targets.
  
  
  
  We investigated the hypothesis that reduced Toll-like receptor 7 (TLR7)-derived signaling drove the impaired IFN responses to rhinovirus by asthmatic alveolar macrophages (AMs); the molecular mechanisms underlying this deficiency were explored.
  
  
  
  AMs were recovered from bronchoalveolar lavage from healthy subjects and patients with severe asthma. Expression of pattern-recognition receptors and microRNAs was evaluated by quantitative polymerase chain reaction and Western blotting. A TLR7-luciferase reporter construct was created to evaluate binding of microRNAs to the 3' untranslated region of TLR7. IFN production was measured by quantitative polymerase chain reaction and ELISA.
  
  
  
  The expression of TLR7 was significantly reduced in severe asthma AMs and was associated with reduced rhinovirus and imiquimod-induced IFN responses by these cells compared with healthy AMs. Severe asthma AMs also expressed increased levels of three microRNAs, which we showed were able to directly reduce TLR7 expression. Ex vivo knockdown of these microRNAs restored TLR7 expression with concomitant augmentation of virus-induced IFN production.
  
  
  
  In severe asthma, TLR7 deficiency drives impaired innate immune responses to virus by AMs. Blocking a group of microRNAs that are up-regulated in these cells can restore antiviral innate responses, providing a novel approach for therapy in asthma.
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Hitasha
authors.initials: H
authors.lastname: Rupani
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Rocio T
authors.initials: RT
authors.lastname: Martinez-Nunez
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Patrick
authors.initials: P
authors.lastname: Dennison
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Laurie C K
authors.initials: LC
authors.lastname: Lau
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Nivenka
authors.initials: N
authors.lastname: Jayasekera
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Havelock
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Ana S
authors.initials: AS
authors.lastname: Francisco-Garcia
authors.affiliation: 2 Hunter Medical Research Institute, University of Newcastle, Newcastle, New South Wales, Australia; and.
authors.forename: Christopher
authors.initials: C
authors.lastname: Grainge
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.|3 NIHR Southampton Respiratory Biomedical Research Unit, Southampton Centre for Biomedical Research, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Howarth
authors.affiliation: 1 Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton School of Medicine, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Tilman
authors.initials: T
authors.lastname: Sanchez-Elsner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000276:immunology*; D015153:Blotting, Western; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D016676:Macrophages, Alveolar / Q000276:immunology; D008297:Male; D035683:MicroRNAs / Q000276:immunology*; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012720:Severity of Illness Index; D051199:Toll-Like Receptor 7 / Q000276:immunology*; D055815:Young Adult
chemical_list: D035683:MicroRNAs; D051199:Toll-Like Receptor 7
keywords: alveolar macrophage; interferon; rhinovirus
references.citation: J Immunol. 2009 Mar 15;182(6):3660-7
references.pmid: 19265144
references.citation: J Biol Chem. 2011 Jan 21;286(3):1786-94
references.pmid: 21097505
references.citation: Thorax. 2015 Sep;70(9):854-61
references.pmid: 26108570
references.citation: J Biol Chem. 2009 Jun 12;284(24):16334-42
references.pmid: 19386588
references.citation: Clin Microbiol Rev. 2001 Oct;14(4):778-809, table of contents
references.pmid: 11585785
references.citation: Int Arch Allergy Immunol. 2011;155 Suppl 1:27-33
references.pmid: 21646792
references.citation: J Allergy Clin Immunol. 2013 Sep;132(3):758-761.e3
references.pmid: 23727038
references.citation: J Immunol. 1996 Jan 15;156(2):621-7
references.pmid: 8543813
references.citation: Curr Opin Virol. 2011 Dec;1(6):519-25
references.pmid: 22328912
references.citation: Allergy. 2013 Dec;68(12):1520-31
references.pmid: 24410781
references.citation: PLoS One. 2009 Jun 12;4(6):e5889
references.pmid: 19521514
references.citation: Am J Respir Cell Mol Biol. 2006 Feb;34(2):192-203
references.pmid: 16210696
references.citation: Proc Natl Acad Sci U S A. 2003 May 27;100(11):6646-51
references.pmid: 12738885
references.citation: Thorax. 2014 Mar;69(3):240-6
references.pmid: 24127021
references.citation: Cell. 2005 Jan 14;120(1):15-20
references.pmid: 15652477
references.citation: Eur Respir J. 2013 Mar;41(3):695-705
references.pmid: 22790917
references.citation: J Biol Chem. 1999 Apr 2;274(14):9707-20
references.pmid: 10092659
references.citation: N Engl J Med. 2013 May 2;368(18):1685-94
references.pmid: 23534542
references.citation: Eur Respir J. 2002 Jan;19(1):61-7
references.pmid: 11843329
references.citation: Am J Respir Crit Care Med. 2011 Mar 15;183(6):734-42
references.pmid: 20889904
references.citation: Proc Natl Acad Sci U S A. 2010 May 11;107(19):8800-5
references.pmid: 20421463
references.citation: Am J Respir Crit Care Med. 2014 Jul 15;190(2):145-54
references.pmid: 24937476
references.citation: Immunity. 2007 Aug;27(2):240-52
references.pmid: 17723216
references.citation: Virology. 2000 Apr 10;269(2):239-47
references.pmid: 10753702
references.citation: Immunol Cell Biol. 2007 Aug-Sep;85(6):435-45
references.pmid: 17667934
references.citation: J Immunol. 2010 Mar 1;184(5):2518-27
references.pmid: 20100933
references.citation: J Virol. 2006 Aug;80(16):8248-58
references.pmid: 16873280
references.citation: J Exp Med. 2005 Mar 21;201(6):937-47
references.pmid: 15781584
references.citation: Lancet. 2002 Mar 9;359(9309):831-4
references.pmid: 11897281
references.citation: Am J Respir Cell Mol Biol. 2014 Jan;50(1):7-17
references.pmid: 23944957
references.citation: Eur Respir J. 2002 Jan;19(1):68-75
references.pmid: 11852895
references.citation: Chest. 1993 Jul;104(1):32-7
references.pmid: 8325105
references.citation: Chest. 2014 Jun;145(6):1219-29
references.pmid: 24457412
references.citation: Thorax. 2008 Jun;63(6):519-25
references.pmid: 18245149
references.citation: Am J Respir Crit Care Med. 2005 Oct 15;172(8):972-9
references.pmid: 16040786
references.citation: Science. 2004 Mar 5;303(5663):1529-31
references.pmid: 14976261
references.citation: Clin Exp Allergy. 2014 Feb;44(2):184-96
references.pmid: 24447081
references.citation: Cell. 2004 Jan 23;116(2):281-97
references.pmid: 14744438
references.citation: Nat Med. 2006 Sep;12(9):1023-6
references.pmid: 16906156
references.citation: Am J Respir Crit Care Med. 2012 Nov 15;186(10):965-74
references.pmid: 22955319
references.citation: J Allergy Clin Immunol. 2014 Apr;133(4):1227-30
references.pmid: 24529411
references.citation: Am J Respir Cell Mol Biol. 2010 Apr;42(4):404-14
references.pmid: 19502390
references.citation: Am J Respir Crit Care Med. 2005 Aug 15;172(4):433-9
references.pmid: 15894599
references.citation: Thorax. 2001 Mar;56 Suppl 1:i1-21
references.pmid: 11158709
references.citation: Oncogene. 2010 Apr 15;29(15):2161-4
references.pmid: 20190803
references.citation: Am J Respir Crit Care Med. 2006 Jul 1;174(1):31-40
references.pmid: 16574934
references.citation: J Biol Chem. 2010 Nov 19;285(47):36698-708
references.pmid: 20847043
references.citation: Eur Respir J. 1999 Oct;14(4):902-7
references.pmid: 10573240
references.citation: Am J Respir Cell Mol Biol. 2012 Oct;47(4):536-42
references.pmid: 22679274
references.citation: J Allergy Clin Immunol. 2012 Jun;129(6):1506-1514.e6
references.pmid: 22657407
references.citation: BMJ. 1993 Oct 16;307(6910):982-6
references.pmid: 8241910
references.citation: Proc Natl Acad Sci U S A. 2008 Sep 9;105(36):13562-7
references.pmid: 18768794
references.citation: Clin Exp Allergy. 2014 Jan;44(1):91-101
references.pmid: 24131248
references.citation: J Infect. 2013 Feb;66(2):163-9
references.pmid: 23201152
references.citation: Clin Exp Allergy. 2010 Aug;40(8):1203-13
references.pmid: 20545701
references.citation: J Infect Dis. 2002 Mar 15;185(6):734-43
references.pmid: 11920291
references.citation: J Allergy Clin Immunol. 2011 May;127(5):1148-54.e9
references.pmid: 21329968
references.citation: Respir Res. 2014 Jun 27;15:72
references.pmid: 24972601
references.citation: BMC Pulm Med. 2011 May 23;11:29
references.pmid: 21605405
references.citation: J Pharmacol Sci. 2010;114(3):264-8
references.pmid: 20953121
references.citation: Eur Respir J. 2010 Jan;35(1):64-71
references.pmid: 19643938