Open AccessFull Spectrum of LPS Activation in Alveolar Macrophages of Healthy Volunteers by Whole Transcriptomic Profiling
Author(s) -
Miguel Pinilla Vera,
Zeyu Xiong,
Yutong Zhao,
Jing Zhao,
Michael P. Donahoe,
Suchitra Barge,
William Horne,
Jay K. Kolls,
Bryan J. McVerry,
Anastasiya Birukova,
Robert Tighe,
W. Michael Foster,
John W. Hollingsworth,
Anuradha Ray,
Rama K. Mallampalli,
Prabir Ray,
Janet Lee
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0159329
Subject(s) - biology , transcriptome , gene knockdown , interferon , interleukin 10 , irf5 , microbiology and biotechnology , cytokine , interferon regulatory factors , immunology , gene , gene expression , innate immune system , immune system , genetics
Despite recent advances in understanding macrophage activation, little is known regarding how human alveolar macrophages in health calibrate its transcriptional response to canonical TLR4 activation. In this study, we examined the full spectrum of LPS activation and determined whether the transcriptomic profile of human alveolar macrophages is distinguished by a TIR-domain-containing adapter-inducing interferon-β (TRIF)-dominant type I interferon signature. Bronchoalveolar lavage macrophages were obtained from healthy volunteers, stimulated in the presence or absence of ultrapure LPS in vitro, and whole transcriptomic profiling was performed by RNA sequencing (RNA-Seq). LPS induced a robust type I interferon transcriptional response and Ingenuity Pathway Analysis predicted interferon regulatory factor ( IRF)7 as the top upstream regulator of 89 known gene targets. Ubiquitin-specific peptidase (USP)-18, a negative regulator of interferon α/β responses, was among the top up-regulated genes in addition to IL10 and USP41 , a novel gene with no known biological function but with high sequence homology to USP18 . We determined whether IRF-7 and USP-18 can influence downstream macrophage effector cytokine production such as IL-10. We show that IRF-7 siRNA knockdown enhanced LPS-induced IL-10 production in human monocyte-derived macrophages, and USP-18 overexpression attenuated LPS-induced production of IL-10 in RAW264.7 cells. Quantitative PCR confirmed upregulation of USP18 , USP41 , IL10 , and IRF7 . An independent cohort confirmed LPS induction of USP41 and IL10 genes. These results suggest that IRF-7 and predicted downstream target USP18, both elements of a type I interferon gene signature identified by RNA-Seq, may serve to fine-tune early cytokine response by calibrating IL-10 production in human alveolar macrophages.