In vivo interferon-gamma induced changes in gene expression dramatically alter neutrophil phenotype.

Daniel R Ambruso,Alexander D Tran,Angelina F Baroffio,Katherine Gowan,John R Murphy,Michael Ellison,Natalie J Briones,Kenneth L Jones,Bridget Sanford,Jan H.N Lindeman

doi:10.1371/journal.pone.0263370

Abstract

The cytokine Interferon-γ (IFN-γ) exerts powerful immunoregulatory effects on the adaptive immune system and also enhances functions of the neutrophil (PMN). The clinical use of IFN-γ has been driven by the finding that its administration to patients with chronic granulomatous disease (CGD) results in decreased incidence and severity of infections. However, IFN-γ has no effect on the characteristic defect of CGD, the inability to convert oxygen to microbicidal metabolites including superoxide anion (O2-) during the phagocytosis associated oxidative burst. We administered varying doses of IFN-γ to adult volunteers and studied the effects on plasma drug levels and response molecules and PMNs isolated from blood drawn at intervals over a 96- hour period. Plasma concentrations of IFN-γ, IP-10 and neopterin, and stimulated release of O2- from PMNs exhibited dose- and time-dependent increases after IFN-γ administration. Gene expression in PMNs was altered for 2775 genes; changes occurred rapidly after administration and returned to baseline in 24–36 hours. Several genes involved with neutrophil host defense were upregulated including those for components of the O2- generating NADPH oxidase; innate-immune and Fc receptors; proteins involved in MHCI and II; a regulator of circulating PMN number; guanylate binding proteins; and a key enzyme in synthesis of an essential NOS cofactor. Coordinate changes were detected in protein levels of representative products from several of these genes. Lysates from isolated neutrophils also demonstrated a spike in NO following IFN-γ administration. IFN-γ appears to increase non-oxygen dependent microbicidal functions of PMNs which could provide strategies to compensate for deficiencies, explain its clinical benefit for CGD patients and expand therapeutic applications of IFN-γ to other disorders.Trial registration: Protocol registered in ClinicalTrials.gov, NCT02609932, Effect of IFN-γ on Innate Immune Cells.

Highlights

Named for their potent ability to interfere with viral infections, interferons (IFNs) are powerful regulators of the immune system [1, 2]
Neopterin is a small molecule metabolite in the Biopterin pathway that is known to be upregulated in response to IFN-γ [13]
Interferon-gamma and neutrophil gene expression antimicrobial phenotype of neutrophils in patients treated with IFN-γ; and we examined our gene expression data, S1 Table, to see if transcription of any GBP genes were upregulated in this study

Summary

Introduction

Named for their potent ability to interfere with viral infections, interferons (IFNs) are powerful regulators of the immune system [1, 2]. It has been demonstrated that IFN-γ alters myeloid cell activity in diverse ways including, increased MHCII protein expression, altered cytokine and chemokine production, enhanced NADPH oxidase activity/oxidative burst, increased nitric oxide (NO) production, increased phagocytosis and cytocidal effects, increased Fc receptor expression, inhibition of chemotaxis and suppression of apoptosis [4]. Most of these changes have been documented as in vitro effects on mature neutrophils, recent studies show that more dramatic changes occur when IFN-γ interacts with maturing myeloid cells [5]. To expand our understanding of the role of IFN-γ in the functional integrity of the neutrophil, we studied its in vivo effects on neutrophils from healthy adult volunteers

Study design

Experimental procedures

Statistical methods

Results

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