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Aim: Periodontitis (PD) is the sixth most prevalent disease around the world and is involved in the development and progression of multiple systemic diseases. Previous studies have reported that PD may aggravate liver injuries. The objective of this study was to investigate whether and how PD affects liver fibrosis. Materials and Methods: Ligature‐induced PD (LIP) was induced in male C57/B6J mice, and sub‐gingival plaques (PL) from patients with PD were applied to mouse teeth. Liver fibrosis was induced by carbon tetrachloride (CCl4) injection. The mice were randomly divided into six groups: Oil, Oil+LIP, Oil+LIP+PL, CCl4, CCl4+LIP, and CCl4+LIP+PL. Alveolar bone resorption was evaluated by methylene blue staining. Hepatic function was analysed by serum alanine aminotransferase and hepatic hydroxyproline. Picrosirius red and α‐smooth muscle actin (SMA) staining were used to evaluate the fibrotic area. RNA sequencing and quantitative RT‐PCR were used to measure gene expression. Western blotting was used to measure protein levels. Flow cytometry was used to analyse the accumulation of immune cells. Mouse microbiota were analysed using 16S rRNA gene sequencing. Results: Mice in the CCl4+LIP+PL group displayed higher serum alanine aminotransferase and hepatic hydroxyproline as well as more Picrosirius red‐positive and α‐SMA‐positive areas in liver samples than those of the CCl4 group, suggesting that PD (LIP+PL) aggravated CCl4‐induced hepatic dysfunction and liver fibrosis. Consistently, the expression of fibro‐genic genes and the protein levels of transforming growth factor β were much higher in the CCl4+LIP+PL group than in the CCl4 group. Flow cytometry revealed that PD increased the accumulation of immune cells, including Kupffer cells, B cells, and Th17 cells, in the liver of mice with CCl4 treatment. PD also increased the expression of inflammatory genes and activated pro‐inflammatory nuclear factor‐kappa B pathway in the livers of CCl4‐injected mice. Moreover, PD altered both oral and liver microbiota in CCl4‐injected mice. Conclusions: PD aggravates CCl4‐induced hepatic dysfunction and fibrosis in mice, likely through the increase of inflammation and alteration of microbiota in the liver. [ABSTRACT FROM AUTHOR]

High mobility group box 1 (HMGB1) is a nuclear protein that can be released from activated or dead cells. Extracellular HMGB1 can serve as a 'danger signal' and novel cytokine that mediates sterile inflammation. In addition to its soluble form, extracellular HMGB1 can also be carried by membrane microvesicles. However, the cellular mechanisms responsible for nuclear HMGB1 translocation to the plasma membrane and release onto membrane microvesicles have not been investigated. Tobacco smoking is a major cause of sterile inflammation in many diseases. Smoking also increases blood levels of HMGB1. In this study, we found that exposure of macrophages to tobacco smoke extract (TSE) stimulated HMGB1 expression, redistribution, and release into the extracellular milieu both as a soluble molecule and, surprisingly, as a microvesicle-associated form (TSE-MV). Inhibition of chromosome region maintenance-1 (CRM1), a nuclear exporter, attenuated TSE-induced HMGB1 redistribution from the nucleus to the cytoplasm, and then its release on TSE-MVs. Our study demonstrates a novel mechanism for the translocation of nuclear HMGB1 to the plasma membrane, and then its release in a microvesicle-associated form. J. Cell. Physiol. 231: 2319-2326, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]