HMGB1 cytoplasmic translocation in patients with acute liver failure

Department of Infectious Diseases, Xiangya Hospital, Central South University, Changsha, 410008 Hunan, PR China.
BMC Gastroenterology (Impact Factor: 2.37). 03/2011; 11(1):21. DOI: 10.1186/1471-230X-11-21
Source: PubMed


High-mobility group box 1 (HMGB1) is a late mediator of lethal systemic inflammation. Acute liver failure (ALF) has been shown to trigger systemic inflammation in clinical and animal studies. To evaluate the possibility of HMGB1 cytoplasmic translocation in ALF, we determined whether HMGB1 is released in hepatocytes and end organ in patients with liver failure/injury.
HepG2 cell were stimulated with LPS or TNF-α, the increase of HMGB1 extracellularly in the culture medium and intracellularly in various cellular fractions were determined by western blot or immunocytochemistry. To observe sub-cellular location of HMGB1 in hepatocytes, liver specimens were obtained from 6 patients with ALF caused by HBV infection, 10 patients with chronic viral hepatitis B, 6 healthy controls, as well as animals model of ALF by intraperitoneal administration of D-GalN (600 mg/kg) and LPS (0.5 mg/kg).
In HepG2 cell culture, LPS or TNF actively induced HMGB1 cytoplasmic translocation and release in a time- and dose-dependent fashion. In animal model of ALF, cytoplasmic HMGB1 translocation was observed in hepatocyts as early as 3 hours post onset of ALF. In patients with ALF caused by HBV infection, cytoplasmic HMGB1 translocation was similarly observed in some hepatocytes of the liver specimen.
Cytoplasmic HMGB1 translocation may occur during ALF, which may potentially contribute to the pathogenesis of liver inflammatory diseases.

Download full-text


Available from: Shushan Zhao
  • Source
    • "Furthermore, the immunofluorescence pictures on undifferentiated ASCs showed a translocation of HMGB1 from nucleus to cytoplasm after LPS treatment. These results are in accordance with literature (HepG2, mouse cardiac fibroblasts and RAW264.7 [25] [47] [49]). Other events as oxidative stress could lead to HMGB1 translocation (in human epithelial cells [50]). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Low grade inflammation is one of the major metabolic disorders in case of obesity due to variable secretion of adipose derived cytokines called adipokines. Recently the nuclear protein HMGB1 was identified as an inflammatory alarmin in obesity associated diseases. However HMGB1 role in adipose tissue inflammation is not yet studied. The aim of this study was to prove the expression of HMGB1 in human adipose tissue and to assess the levels of expression between normo-weight and obese individuals. Furthermore we determined which type of cells within adipose tissue is involved in HMGB1 production under inflammatory signal. Western-blot was performed on protein lysates from human normo-weight and obese adipose tissue to study the differential HMGB1 expression. Human normo-weight adipose tissue, adipose-derived stromal cells (ASCs) and adipocytes were cultured and stimulated with LPS to induce inflammation. HMGB1, IL-6 and MCP-1 secretion and gene expression were quantified by ELISA and Q-PCR respectively, as well as cell death by LDH assay. HMGB1 translocation during inflammation was tracked down by immunofluorescence in ASCs. HMGB1 was expressed 2-fold more in adipose tissue from obese compared to normo-weight individuals. LPS led to an up-regulation in HMGB1 secretion and gene expression in ASCs, while no change was noticed in adipocytes. Moreover, this HMGB1 release was not attributable to any cell death. In LPS-stimulated ASCs, HMGB1 translocation from nucleus to cytoplasm was detectable at 12h and the nuclear HMGB1 was completely drained out after 24h of treatment. The expression level studies between adipose tissue from normo-weight and obese individuals together with in vitro results strongly suggest that adipose tissue secretes HMGB1 in response to inflammatory signals which characterized obesity.
    Full-text · Article · Aug 2013 · Cytokine
  • Source
    • "Thus, hepatocytes have been shown to secrete ATP, most likely via pannexin 1 channels, as they succumb to FFAs [142] and acetaminophen [143], promoting the P2Y2-dependent infiltration of neutrophils and hence aggravating hepatic damage [143]. The non-histone chromatin-binding protein HMGB1 gets massively released by the hepatocytes of patients undergoing acute liver failure [144] [145] as well as in rodent models of hepatic IR [146] [147], hepatitis B virus (HBV) infection [148] and concavalin A intoxication [145] [149], de facto playing a major etiological role in these settings (as demonstrated by pharmacological and genetic experiments). Upon binding to TLR9, nuclear DNA released by acetaminophen-exposed hepatocytes promotes the differentiation of hepatic stellate cells (HSCs), hence favoring the secretion of collagen and other fibrosis-associated factors [150], as well as the production of proinflammatory cytokines such as IL-1b and IL-18 by tissue-resident and freshly recruited immune cells [151]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Inflammation can be either beneficial or detrimental for the liver, depending on multiple factors. Mild (i.e., limited in intensity and destined to resolved) inflammatory responses have indeed been shown to exert consistent hepatoprotective effects, contributing to tissue repair and promoting the reestablishment of homeostasis. Conversely, excessive (i.e., disproportionate in intensity and permanent) inflammation may induce a massive loss of hepatocytes and hence exacerbate the severity of various hepatic conditions, including ischemia-reperfusion injury, systemic metabolic alterations (e.g., obesity, diabetes, non-alcoholic fatty liver disorders), alcoholic hepatitis, intoxication by xenobiotics and infection, de facto being associated with irreversible liver damage, fibrosis and carcinogenesis. Both liver-resident cells (e.g., Kupffer cells, hepatic stellate cells, sinusoidal endothelial cells) and cells that are recruited in response to injury (e.g., monocytes, macrophages, dendritic cells, natural killer cells) emit pro-inflammatory signals including - but not limited to - cytokines, chemokines, lipid messengers and reactive oxygen species that contribute to the apoptotic or necrotic demise of hepatocytes. In turn, dying hepatocytes release damage-associated molecular patterns that - upon binding to evolutionary conserved pattern recognition receptors - activate cells of the innate immune system to further stimulate inflammatory responses, resulting in the establishment of a highly hepatotoxic feedforward cycle of inflammation and cell death. In this review, we discuss the cellular and molecular mechanisms that account for the most deleterious effect of hepatic inflammation at the cellular level, that is, the initiation of a massive cell death response among hepatocytes.
    Full-text · Article · Apr 2013 · Journal of Hepatology
  • Source
    • "Although it is not yet fully understood whether apoptosis or necrosis predominates in acute liver injury [4], it is clear that treatment should target the downstream consequences of inflammatory activation. It may therefore be important to identify the signals that modulate the subsequent cellular and molecular mechanisms responsible for liver cell death, in order to develop treatments to encourage regeneration, rather than cell death [4] [5] [6]. Besides the known cholinergic pathways involved in autonomic regulation, the 'cholinergic anti-inflammatory pathway' that inhibits macrophage cytokine production has been discovered [7] [8] [9]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction Acute liver failure (ALF), like sepsis, is associated with an overwhelming activation of the immune response in which hepatic and circulating inflammatory cytokines play a pivotal role. Cholinesterase inhibition has been shown to have anti-inflammatory properties in experimental sepsis. We investigated the role of neostigmine in attenuating d-galactosamine (d-GalN)-induced ALF. Methods Thirty-six female wistar rats were randomly allocated to three groups: a control group, a d-GalN group receiving a single i.p. injection of d-galactosamine (400 mg kg−1 BW) and a neostigmine-treated d-GalN group receiving a single i.p. injection of d-galactosamine followed 24 h later by i.p. injection of neostigmine methylsulfate 0.25% (80 μg kg−1 BW) three times daily for 3 successive days. Rats were sacrificed 24 h after the last injection. Plasma levels of liver transaminases, total proteins, albumin, prothrombin, total bilirubin and hepatic levels of superoxide dismutase and malondialdehyde were measured. Liver expression of cytokines (HMGB-1, TNF-α and IL-10) and histopathology were evaluated. Results Neostigmine attenuated liver dysfunction and improved liver synthetic and excretory functions, reduced proinflammatory cytokine HMGB1 (95% CI 0.33–1.09) and TNF-α (95% CI 1.26–2.06) expression compared to d-GalN group (95% CI 2.67–4.73 and 7.33–14.53, respectively, P < 0.001) and increased expression of the anti-inflammatory cytokine IL-10 in liver tissue (95% CI 2.49–4.17 vs 0.04–0.21 in d-GalN group, P < 0.001). Neostigmine also significantly increased antioxidant level, and decreased oxidative burden caused by d-GaIN. Conclusion Neostigmine improved liver function in a rat ALF model through an anti-inflammatory activity.
    Full-text · Article · Apr 2013
Show more