title: Hepatic mitochondrial DNA/Toll-like receptor 9/MicroRNA-223 forms a negative feedback loop to limit neutrophil overactivation and acetaminophen hepatotoxicity in mice.
abstract: Acetaminophen (APAP) overdose is a leading cause of acute liver failure worldwide, in which mitochondrial DNA (mtDNA) released by damaged hepatocytes activates neutrophils through binding of Toll-like receptor 9 (TLR9), further aggravating liver injury. Here, we demonstrated that mtDNA/TLR9 also activates a negative feedback pathway through induction of microRNA-223 (miR-223) to limit neutrophil overactivation and liver injury. After injection of APAP in mice, levels of miR-223, the most abundant miRNAs in neutrophils, were highly elevated in neutrophils. Disruption of the miR-223 gene exacerbated APAP-induced hepatic neutrophil infiltration, oxidative stress, and injury and enhanced TLR9 ligand-mediated activation of proinflammatory mediators in neutrophils. An additional deletion of the intercellular adhesion molecule 1 (ICAM-1) gene ameliorated APAP-induced neutrophil infiltration and liver injury in miR-223 knockout mice. In vitro experiments revealed that miR-223-deficient neutrophils were more susceptible to TLR9 agonist-mediated induction of proinflammatory mediators and nuclear factor kappa B (NF-κB) signaling, whereas overexpression of miR-223 attenuated these effects in neutrophils. Moreover, inhibition of TLR9 signaling by either treatment with a TLR9 inhibitor or by disruption of TLR9 gene partially, but significantly, suppressed miR-223 expression in neutrophils post-APAP injection. In contrast, activation of TLR9 up-regulated miR-223 expression in neutrophils in vivo and in vitro. Mechanistically, activation of TLR9 up-regulated miR-223 by enhancing NF-κB binding on miR-223 promoter, whereas miR-223 attenuated TLR9/NF-κB-mediated inflammation by targeting IκB kinase α expression. Collectively, up-regulation of miR-223 plays a key role in terminating the acute neutrophilic response and is a therapeutic target for treatment of APAP-induced liver failure. (Hepatology 2017;66:220-234).
authors.affiliation: School of Pharmacy, Anhui Medical University, Hefei, China.|Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.|Institute for Liver Diseases, Anhui Medical University, Hefei, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Dechun
authors.initials: D
authors.lastname: Feng
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Man
authors.initials: M
authors.lastname: Li
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Yanhang
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Teresa
authors.initials: T
authors.lastname: Ramirez
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Haixia
authors.initials: H
authors.lastname: Cao
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Seung-Jin
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: School of Pharmacy, Anhui Medical University, Hefei, China.|Institute for Liver Diseases, Anhui Medical University, Hefei, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Yan
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Ju
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.|Institute for Liver Diseases, Anhui Medical University, Hefei, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Pharmacy, Anhui Medical University, Hefei, China.|Institute for Liver Diseases, Anhui Medical University, Hefei, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.
authors.forename: Bin
authors.initials: B
authors.lastname: Gao
mesh_terms: D000082:Acetaminophen / Q000494:pharmacology / Q000633:toxicity*; D000818:Animals; D002478:Cells, Cultured; D004272:DNA, Mitochondrial / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects*; D017114:Liver Failure, Acute / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics*; D009504:Neutrophils / Q000166:cytology; D011897:Random Allocation; D012016:Reference Values; D015398:Signal Transduction; D051217:Toll-Like Receptor 9 / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D004272:DNA, Mitochondrial; D035683:MicroRNAs; D051217:Toll-Like Receptor 9; D000082:Acetaminophen