Description | AUTHORS - Pedro E. Marques,1,2 Sylvia S. Amaral,1,2 Daniele A. Pires,1,2 Laura L. Nogueira,1,2 Frederico M. Soriani,2,9
Braulio H.F. Lima,2 Gabriel A.O. Lopes,2,3 Remo C. Russo,2,3 Thiago V. A´ vila,2,4 Juliana G. Melgac¸o,5
Andr e G. Oliveira,1 Marcelo A. Pinto,5 Cristiano X. Lima,2,6 Ana Maria De Paula,7 Denise C. Cara,1
Maria F. Leite,3,8 Mauro M. Teixeira,2 and Gustavo Batista Menezes1,2; AFFILIATIONS - 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-1b, 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-a, tumor necrosis
factor alpha; UFMG, Universidade Federal de Minas Gerais.
From the 1Laborat orio de Imunobiofotoˆnica, Departamento de Morfologia; 2Laborat orio de Imunofarmacologia, Departamento de Bioquı´mica e Imunologia;
3Departamento de Fisiologia e Biofı´sica; 4Departamento de Microbiologia, Instituto de Cieˆncias Biol ogicas, Universidade Federal de Minas Gerais, Belo Horizonte,
Brazil; 5Laborat orio de Desenvolvimento Tecnol ogico em Virologia, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil; 6Departamento de Cirurgia, Faculdade de
Medicina; 7Departamento de Fı´sica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; 8Howard Hughes Medical Institute, Chevy Chase, MD; and
9Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Brazil. | pt_BR |
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
(TLR92/2 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. | pt_BR |