Chemokines and mitochondrial products activate neutrophils... : Hepatology (original) (raw)

Liver Biology/Pathobiology

Chemokines and mitochondrial products activate neutrophils to amplify organ injury during mouse acute liver failure

Marques, Pedro E.1,2; Amaral, Sylvia S.1,2; Pires, Daniele A.1,2; Nogueira, Laura L.1,2; Soriani, Frederico M.2,9; Lima, Braulio H.F.2; Lopes, Gabriel A.O.2,3; Russo, Remo C.2,3; Ávila, Thiago V.2,4; Melgaço, Juliana G.5; Oliveira, André G.1; Pinto, Marcelo A.5; Lima, Cristiano X.2,6; De Paula, Ana Maria7; Cara, Denise C.1; Leite, Maria F.3,8; Teixeira, Mauro M.2; Menezes, Gustavo Batista1,2*

1 Laboratório de Imunobiofotônica, Departamento de Morfologia

2 Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia

3 Departamento de Fisiologia e Biofísica

4 Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil

5 Laboratório de Desenvolvimento Tecnológico em Virologia, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil

6 Departamento de Cirurgia, Faculdade de Medicina

7 Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil

8 Howard Hughes Medical Institute, Chevy Chase, MD

9 Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Brazil

* Address reprint requests to: Ph.D., Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Antônio Carlos 6627, Pampulha, Belo Horizonte 31270-901, Minas Gerais, Brazil

Email:[email protected]

Received 12 March 2012; Accepted 16 April 2012

Grant sponsor: National Council for Scientific and Technological Development; Grant sponsor: Coordination for the Improvement of Higher Education Personnel; Grant sponsor: Foundation for Research Support of Minas Gerais; Grant sponsor: Centers of Excellence; Grant sponsor: Howard Hughes Medical Institute.

Potential conflict of interest: Nothing to report.

See Editorial on Page 1599

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Abstract

Acetaminophen (APAP) is a safe analgesic and antipyretic drug. However, APAP overdose leads to massive hepatocyte death. Cell death during APAP toxicity occurs by oncotic necrosis, in which the release of intracellular contents can elicit a reactive inflammatory response. We have previously demonstrated that an intravascular gradient of chemokines and mitochondria-derived formyl peptides collaborate to guide neutrophils to sites of liver necrosis by CXC chemokine receptor 2 (CXCR2) and formyl peptide receptor 1 (FPR1), respectively. Here, we investigated the role of CXCR2 chemokines and mitochondrial products during APAP-induced liver injury and in liver neutrophil influx and hepatotoxicity. During APAP overdose, neutrophils accumulated into the liver, and blockage of neutrophil infiltration by anti–granulocyte receptor 1 depletion or combined CXCR2-FPR1 antagonism significantly prevented hepatotoxicity. In agreement with our in vivo data, isolated human neutrophils were cytotoxic to HepG2 cells when cocultured, and the mechanism of neutrophil killing was dependent on direct contact with HepG2 cells and the CXCR2-FPR1–signaling pathway. Also, in mice and humans, serum levels of both mitochondrial DNA (mitDNA) and CXCR2 chemokines were higher during acute liver injury, suggesting that necrosis products may reach remote organs through the circulation, leading to a systemic inflammatory response. Accordingly, APAP-treated mice exhibited marked systemic inflammation and lung injury, which was prevented by CXCR2-FPR1 blockage and Toll-like receptor 9 (TLR9) absence (TLR9−/− mice).

Conclusion:

Chemokines and mitochondrial products (e.g., formyl peptides and mitDNA) collaborate in neutrophil-mediated injury and systemic inflammation during acute liver failure. Hepatocyte death is amplified by liver neutrophil infiltration, and the release of necrotic products into the circulation may trigger a systemic inflammatory response and remote lung injury.

Abbreviations: ALF, acute liver failure; ALT, alanine aminotransferase; ANOVA, analysis of variance; APAP, acetaminophen; BAL, bronchoalveolar lavage; CXCR2, CXC chemokine receptor 2; DCF-DA, 2′,7′-dichlorodihydrofluorescein diacetate; DILI, drug-induced liver injury; ELISA, enzyme-linked immunosorbent assay; FPR1, formyl peptide receptor 1; gDNA, genomic DNA; GR1, granulocyte receptor 1; IgG, immunoglobulin G; IL-1β, interleukin-1 beta; I/R, ischemia/reperfusion; IV, intravenous; IVM, intravital microscopy; LT, liver transplantation; Lysm-eGFP, lysozyme M promoter for enhanced green fluorescent protein; mitDNA, mitochondrial DNA; MPO, myeloperoxidase; nDNA, nuclear DNA; NO, nitric oxide; PCR, polymerase chain reaction; PE, phycoerythrin; PECAM-1, platelet-endothelial cell adhesion molecule-1; ROS, reactive oxygen species; SEM, standard error of the mean; TLR9, Toll-like receptor 9; TNF-α, tumor necrosis factor alpha; UFMG, Universidade Federal de Minas Gerais.