Hepatic DNA deposition drives drug-induced liver injury and inflammation in mice.
Drug-induced liver injury (DILI) is an important cause of acute liver failure, with limited therapeutic options. During DILI, oncotic necrosis with concomitant release and recognition of intracellular content amplifies liver inflammation and injury. Among these molecules, self-DNA has been widely shown to trigger inflammatory and autoimmune diseases; however, whether DNA released from damaged hepatocytes accumulates into necrotic liver and the impact of its recognition by the immune system remains elusive. Here we show that treatment with two different hepatotoxic compounds (acetaminophen and thioacetamide) caused DNA release into the hepatocyte cytoplasm, which occurred in parallel with cell death in vitro. Administration of these compounds in vivo caused massive DNA deposition within liver necrotic areas, together with an intravascular DNA coating. Using confocal intravital microscopy, we revealed that liver injury due to acetaminophen overdose led to a directional migration of neutrophils to DNA-rich areas, where they exhibit an active patrolling behavior. DNA removal by intravenous DNASE1 injection or ablation of Toll-like receptor 9 (TLR9)-mediated sensing significantly reduced systemic inflammation, liver neutrophil recruitment, and hepatotoxicity. Analysis of liver leukocytes by flow cytometry revealed that emigrated neutrophils up-regulated TLR9 expression during acetaminophen-mediated necrosis, and these cells sensed and reacted to extracellular DNA by activating the TLR9/NF-κB pathway. Likewise, adoptive transfer of wild-type neutrophils to TLR9(-/-) mice reversed the hepatoprotective phenotype otherwise observed in TLR9 absence.


CONCLUSIONS
Hepatic DNA accumulation is a novel feature of DILI pathogenesis. Blockage of DNA recognition by the innate immune system may constitute a promising therapeutic venue.
Laboratório de Imunobiofotônica, Departamento de Morfologia, ICB, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
Pedro Elias
PE
Marques
André Gustavo
AG
Oliveira
Rafaela Vaz
RV
Pereira
Bruna Araújo
BA
David
Lindisley Ferreira
LF
Gomides
Adriana Machado
AM
Saraiva
Daniele Araújo
DA
Pires
Júlia Tosta
JT
Novaes
Daniel O
DO
Patricio
Daniel
D
Cisalpino
Zélia
Z
Menezes-Garcia
W Matthew
WM
Leevy
Sarah Ellen
SE
Chapman
GermánArturo
G
Mahecha
Rafael Elias
RE
Marques
Rodrigo
R
Guabiraba
Vicente Paulo
VP
Martins
Danielle Gloria
DG
Souza
Daniel Santos
DS
Mansur
Mauro Martins
MM
Teixeira
M Fatima
MF
Leite
Gustavo Batista
GB
Menezes
D000082:Acetaminophen / Q000009:adverse effects; D018712:Analgesics, Non-Narcotic / Q000009:adverse effects; D000818:Animals; D056486:Chemical and Drug Induced Liver Injury / Q000276:immunology* / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018375:Neutrophil Activation; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D051217:Toll-Like Receptor 9 / Q000378:metabolism
D018712:Analgesics, Non-Narcotic; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9; D000082:Acetaminophen; D004247:DNA