GM-CSF Down-Regulates TLR Expression via the Transcription Factor PU.1 in Human Monocytes.
Toll-like receptors (TLR) are crucial sensors of microbial agents such as bacterial or viral compounds. These receptors constitute key players in the induction of inflammation, e.g. in septic or chronic inflammatory diseases. Colony-stimulating factors (CSFs) such as granulocyte-macrophage-CSF (GM-CSF) or granulocyte-CSF (G-CSF) have been extensively investigated in their capacity to promote myelopoiesis in febrile neutropenia or to overcome immunosuppression in patients suffering from sepsis-associated neutropenia or from monocytic immunoincompetence. We report here that GM-CSF, downregulates TLR1, TLR2 and TLR4 in a time- and dose-dependent fashion in human monocytes. Diminished pathogen recognition receptor expression was accompanied by reduced downstream p38 and extracellular-signal-regulated kinase (ERK) signaling upon lipoteichoic acid (LTA) and lipopolysaccharide (LPS) binding-and accordingly led to impaired proinflammatory cytokine production. Knockdown experiments of the transcription factors PU.1 and VentX showed that GM-CSF driven effects on TLR regulation is entirely PU.1 but not VentX dependent. We further analysed monocyte TLR and CD14 expression upon exposure to the IMID® immunomodulatory drug Pomalidomide (CC-4047), a Thalidomide analogue known to downregulate PU.1. Indeed, Pomalidomide in part reversed the GM-CSF-mediated effects. Our data indicate a critical role of PU.1 in the regulation of TLR1, 2, 4 and of CD14, thus targeting PU.1 ultimately results in TLR modulation. The PU.1 mediated immunomodulatory properties of GM-CSF should be taken into consideration upon usage of GM-CSF in inflammatory or infection-related conditions.
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Kambis
K
Sadeghi
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Lukas
L
Wisgrill
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Isabelle
I
Wessely
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Susanne C
SC
Diesner
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Simone
S
Schüller
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Celia
C
Dürr
Dept. of Surgery, Medical University of Vienna, Vienna, Austria.
Armando
A
Heinle
Dept. of Surgery, Medical University of Vienna, Vienna, Austria.
Monika
M
Sachet
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Arnold
A
Pollak
Dept. of Paediatrics and Adolescent Medicine, Division of Neonatology, Paediatric Intensive Care & Neuropaediatrics, Medical University of Vienna, Vienna, Austria.
Elisabeth
E
Förster-Waldl
Core Facility Flow Cytometry, Medical University of Vienna, Vienna, Austria.
Andreas
A
Spittler
D016207:Cytokines / Q000096:biosynthesis; D015536:Down-Regulation; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000502:physiology*; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis; D009000:Monocytes / Q000378:metabolism* / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000378:metabolism* / Q000502:physiology; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D051194:Toll-Like Receptor 1 / Q000096:biosynthesis; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis; D051193:Toll-Like Receptors / Q000096:biosynthesis*; D015534:Trans-Activators / Q000378:metabolism* / Q000502:physiology; D000099232:Proto-Oncogene Protein Spi-1
D016207:Cytokines; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D018950:Lipopolysaccharide Receptors; D011518:Proto-Oncogene Proteins; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1; C495342:TLR2 protein, human; C495345:TLR4 protein, human
Adv Exp Med Biol. 2005;560:11-8
15932016
J Neuroinflammation. 2012 Dec 13;9:268
23234315
Clin Infect Dis. 2000 Feb;30(2):256-60
10671324
Pediatr Infect Dis J. 2002 Nov;21(11):1061-5
12442030
J Exp Med. 2008 Nov 24;205(12):2711-6
18955567
Proc Natl Acad Sci U S A. 1994 Jun 7;91(12):5592-6
8202532
J Clin Invest. 2011 Jul;121(7):2599-613
21670496
Blood. 2010 Jan 21;115(3):605-14
19965623
Mediators Inflamm. 2015;2015:568543
25838639
Lancet. 2009 Jan 17;373(9659):226-33
19150703
Trends Cardiovasc Med. 2008 Feb;18(2):52-6
18308195
Nat Biotechnol. 2002 Feb;20(2):155-62
11821861
J Immunol. 2005 Mar 1;174(5):2467-70
15728448
J Exp Med. 2005 May 2;201(9):1487-502
15867096
Nature. 1997 Jul 24;388(6640):394-7
9237759
Am J Respir Cell Mol Biol. 2007 Jan;36(1):114-21
16917076
J Biol Chem. 2000 Mar 31;275(13):9773-81
10734131
Neonatology. 2011;99(1):51-6
20616571
Crit Care. 2011;15(1):R58
21310070
Trends Immunol. 2013 Feb;34(2):81-9
23000011
Biol Blood Marrow Transplant. 2004 Dec;10(12):848-57
15570253
Eur J Immunol. 2006 Feb;36(2):361-70
16402404
Am J Respir Crit Care Med. 2009 Oct 1;180(7):640-8
19590022
Blood. 2006 Apr 15;107(8):3098-105
16373662
Gastroenterology. 2002 Jun;122(7):1987-2000
12055604
Cancer Immunol Immunother. 2009 Jul;58(7):1033-45
19009291
Curr Hematol Rep. 2004 Nov;3(6):406-12
15496273
Nat Immunol. 2004 Oct;5(10):987-95
15454922
Blood. 1994 Nov 1;84(9):2923-9
7524759
Blood. 2002 Dec 1;100(12):4193-200
12393686
Crit Rev Immunol. 2005;25(5):405-28
16167889
Front Immunol. 2014 Apr 22;5:162
24795713