Acetaminophen hepatotoxicity and sterile inflammation: The mechanism of protection of Chlorogenic acid.
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ABSTRACT:
SUBMITTER: Jaeschke H
PROVIDER: S-EPMC4872296 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The metabolic intermediate of acetaminophen (APAP) can cause severe hepatocyte necrosis, which triggers aberrant immune activation of liver non-parenchymal cells (NPC). Overzealous hepatic inflammation determines the morbidity and mortality of APAP-induced liver injury (AILI). Interleukin-1 receptor (IL-1R) signaling has been shown to play a critical role in various inflammatory conditions, but its precise role and underlying mechanism in AILI remain debatable. Herein, we show that NLRP3 inflammasome activation of IL-1? is dispensable to AILI, whereas IL-1?, the other ligand of IL-1R1, accounts for hepatic injury by a lethal dose of APAP. Furthermore, Kupffer cells function as a major source of activated IL-1? in the liver, which is activated by damaged hepatocytes through TLR4/MyD88 signaling. Finally, IL-1? is able to chemoattract and activate CD11b+Gr-1+ myeloid cells, mostly neutrophils and inflammatory monocytes, to amplify deteriorated inflammation in the lesion. Therefore, this work identifies that MyD88-dependent activation of IL-1? in Kupffer cells plays a central role in the immunopathogenesis of AILI and implicates that IL-1? is a promising therapeutic target for AILI treatment.
| S-EPMC6207754 | biostudies-literature
Project description:CONTEXT:Triptolide (TP) has outstanding biological activities, but it induces toxicities, particular hepatotoxicity, severely limiting its clinical application. Chlorogenic acid (CGA) has prominently medicinal and nutritional values. However, until now, it is not known whether CGA could mitigate TP-induced hepatotoxicity. OBJECTIVE:This study explored the possible protection of CGA against TP-induced hepatotoxicity and its potential mechanisms, for the first time. MATERIAL AND METHODS:KM mice were treated orally with TP at a single dose of 1?mg/kg at 4?h after being treated with CGA (10, 20 and 40?mg/kg) for seven continuous days. Blood samples were collected at 24?h after TP administration for measurement of serum biomarkers, and hepatic tissues for analysis of potential mechanisms. RESULTS:TP treatment-induced acute hepatotoxicity manifested by the significant elevation in serum alanine transaminase (93.9?U/L), aspartate transaminase (185.8?U/L) and hepatic malondialdehyde (0.637??mol/mg protein), and the remarkable reduction in hepatic glutathione (1.425??g/mg protein), glutathione S-transferase, glutathione peroxidase, superoxide dismutase and catalase (91.7, 320.7, 360.6 and 140.7?U/mg protein, respectively). In contrast, pretreatment with CGA for 7?days effectively attenuated acute liver injury and oxidative stress caused by TP with each ED50 of 44.4, 57.1, 46.6, 22.2, 40.9, 58.1, 86.4 and 61.0?mg/kg, respectively. Furthermore, pretreatment with CGA promoted the accumulation of Nrf2 into the nucleus, and up-regulated mRNA expression of Nrf2-target downstream genes. DISCUSSION AND CONCLUSIONS:Combined CGA medication may probably reduce the risk of TP poisoning, and in-depth mechanisms can be developed around the signal molecules of Nrf2.
| S-EPMC6300082 | biostudies-literature
Project description:Acetaminophen (APAP) is one of the most popular and safe pain medications worldwide. However, due to its wide availability, it is frequently implicated in intentional or unintentional overdoses where it can cause severe liver injury and even acute liver failure (ALF). In fact, APAP toxicity is responsible for 46% of all ALF cases in the United States. Early mechanistic studies in mice demonstrated the formation of a reactive metabolite, which is responsible for hepatic glutathione depletion and initiation of the toxicity. This insight led to the rapid introduction of N-acetylcysteine as a clinical antidote. However, more recently, substantial progress was made in further elucidating the detailed mechanisms of APAP-induced cell death. Mitochondrial protein adducts trigger a mitochondrial oxidant stress, which requires amplification through a MAPK cascade that ultimately results in activation of c-jun N-terminal kinase (JNK) in the cytosol and translocation of phospho-JNK to the mitochondria. The enhanced oxidant stress is responsible for the membrane permeability transition pore opening and the membrane potential breakdown. The ensuing matrix swelling causes the release of intermembrane proteins such as endonuclease G, which translocate to the nucleus and induce DNA fragmentation. These pathophysiological signaling mechanisms can be additionally modulated by removing damaged mitochondria by autophagy and replacing them by mitochondrial biogenesis. Importantly, most of the mechanisms have been confirmed in human hepatocytes and indirectly through biomarkers in plasma of APAP overdose patients. The extensive necrosis caused by APAP overdose leads to a sterile inflammatory response. Although recruitment of inflammatory cells is necessary for removal of cell debris in preparation for regeneration, these cells have the potential to aggravate the injury. This review touches on the newest insight into the intracellular mechanisms of APAP-induced cells death and the resulting inflammatory response. Furthermore, it discusses the translation of these findings to humans and the emergence of new therapeutic interventions.
| S-EPMC6800176 | biostudies-literature
Project description:Background : Acetaminophen (APAP)-induced liver injury (AILI) is a common cause of drug-induced liver injury (DILI). The mechanism underlying protection in AILI or DILI remains to be elucidated, and the role of early growth response 1 (Egr1) in AILI and potential mechanisms remain to be known. Methods : The role of Egr1 was studied both in vivo and in vitro. Liver-specific Egr1-knockout (Egr1 LKO) mice and those overexpressing Egr1 via tail vein injection of Egr1-expressing adenovirus (Ad-Egr1) were utilized with AILI. Chromatin immunoprecipitation-sequencing, RNA-sequencing, seahorse XF analysis, and targeted fatty acid analysis were performed. EGR1 levels were also studied in liver tissues and serum samples from AILI/DILI patients. Results: In this study, we have demonstrated that Egr1 was upregulated in AILI models in vivo and in vitro. liver-specific Egr1 knockout aggravated AILI; however, Ad-Egr1 treatment ameliorated this. Mechanistically, Egr1 deficiency inhibited, whereas overexpression promoted, mitochondrial respiratory function and fatty acid β-oxidation (FAO) activity in AILI. Egr1 transcriptionally upregulated FAO-related genes in hepatocytes. Notably, the knockdown of acetyl-coenzyme A acyltransferase 2 (Acaa2), a key gene involved in FAO, diminished this protective effect of Egr1. Clinically, EGR1 was markedly increased in liver tissues from AILI patients. Interestingly, EGR1 levels of liver tissues and serum samples were also obviously higher in idiosyncratic DILI patients. Conclusions: Egr1 confers adaptive protection in AILI, mediated via the transcriptional upregulation of Acaa2, which improves mitochondrial FAO, and might be a potential biomarker and novel therapeutic target for AILI.
| S-EPMC9254463 | biostudies-literature
Project description:Cot/tpl2 (MAP3K8) activates MKK1/2-Erk1/2 following stimulation of the Toll-like/IL-1 receptor superfamily. Here, we investigated the role of Cot/tpl2 in sterile inflammation and drug-induced liver toxicity. Cot/tpl2 KO mice exhibited reduced hepatic injury after acetaminophen challenge, as evidenced by decreased serum levels of both alanine and aspartate aminotransferases, decreased hepatic necrosis, and increased survival relative to Wt mice. Serum levels of both alanine and aspartate aminotransferases were also lower after intraperitoneal injection of acetaminophen in mice expressing an inactive form of Cot/tpl2 compared with Wt mice, suggesting that Cot/tpl2 activity contributes to acetaminophen-induced liver injury. Furthermore, Cot/tpl2 deficiency reduced neutrophil and macrophage infiltration in the liver of mice treated with acetaminophen, as well as their hepatic and systemic levels of IL-1?. Intraperitoneal injection of damage-associated molecular patterns from necrotic hepatocytes also impaired the recruitment of leukocytes and decreased the levels of several cytokines in the peritoneal cavity in Cot/tpl2 KO mice compared with Wt counterparts. Moreover, similar activation profiles of intracellular pathways were observed in Wt macrophages stimulated with Wt or Cot/tpl2 KO damage-associated molecular patterns. However, upon stimulation with damage-associated molecular patterns, the activation of Erk1/2 and JNK was deficient in Cot/tpl2 KO macrophages compared with their Wt counterparts; an effect accompanied by weaker release of several cytokines, including IL-1?, an important component in the development of sterile inflammation. Taken together, these findings indicate that Cot/tpl2 contributes to acetaminophen-induced liver injury, providing some insight into the underlying molecular mechanisms.
| S-EPMC3663553 | biostudies-literature
Project description:UnlabelledAcetaminophen (APAP) overdose is a major cause of acute liver failure. The glutathione (GSH) precursor N-acetylcysteine (NAC) is used to treat patients with APAP overdose for up to 48 hours. Although it is well established that early treatment with NAC can improve the scavenging of the reactive metabolite N-acetyl-p-benzoquinone imine, protective mechanisms at later times remain unclear. To address this issue, fasted C3Heb/FeJ mice were treated with 300 mg/kg APAP and then received intravenously 0.65 mmol/kg GSH or NAC at 1.5 hours after APAP. The animals were sacrificed at 6 hours. APAP alone caused severe liver injury with peroxynitrite formation and DNA fragmentation, all of which was attenuated by both treatments. However, GSH (-82%) was more effective than NAC (-46%) in preventing liver injury. Using nuclear magnetic resonance spectroscopy to measure tissue adenosine triphosphate (ATP) levels and the substrate flux through the mitochondrial Krebs cycle, it was observed that the reduced liver injury correlated with accelerated recovery of mitochondrial GSH content, maintenance of ATP levels, and an increased substrate supply for the mitochondrial Krebs cycle compared with APAP alone. NAC treatment was less effective in recovering ATP and mitochondrial GSH levels and showed reduced substrate flux through the Krebs cycle compared with GSH. However, increasing the dose of NAC improved the protective effect similar to GSH, suggesting that the amino acids not used for GSH synthesis were used as mitochondrial energy substrates.ConclusionDelayed treatment with GSH and NAC protect against APAP overdose by dual mechanisms-that is, by enhancing hepatic and mitochondrial GSH levels (scavenging of reactive oxygen and peroxynitrite)-and by supporting the mitochondrial energy metabolism.
| S-EPMC2977522 | biostudies-literature
Project description:Although covalent protein binding is established as the pivotal event underpinning acetaminophen (APAP) toxicity, its mechanistic details remain unclear. In this study, we demonstrated that APAP induces widespread protein glutathionylation in a time-, dose- and bioactivation-dependent manner in HepaRG cells. Proteo-metabonomic mapping provided evidence that APAP-induced glutathionylation resulted in functional deficits in energy metabolism, elevations in oxidative stress and cytosolic calcium, as well as mitochondrial dysfunction that correlate strongly with the well-established toxicity features of APAP. We also provide novel evidence that APAP-induced glutathionylation of carnitine O-palmitoyltransferase 1 (CPT1) and voltage-dependent anion-selective channel protein 1 are respectively involved in inhibition of fatty acid β-oxidation and opening of the mitochondrial permeability transition pore. Importantly, we show that the inhibitory effect of CPT1 glutathionylation can be mitigated by PPARα induction, which provides a mechanistic explanation for the prophylactic effect of fibrates, which are PPARα ligands, against APAP toxicity. Finally, we propose that APAP-induced protein glutathionylation likely occurs secondary to covalent binding, which is a previously unknown mechanism of glutathionylation, suggesting that this post-translational modification could be functionally implicated in drug-induced toxicity.
| S-EPMC6166671 | biostudies-literature
Project description:Background & aimsAcetaminophen (APAP) overdose remains a frequent cause of acute liver failure, which is generally accompanied by increased levels of serum bile acids (BAs). However, the pathophysiological role of BAs remains elusive. Herein, we investigated the role of BAs in APAP-induced hepatotoxicity.MethodsWe performed intravital imaging to investigate BA transport in mice, quantified endogenous BA concentrations in the serum of mice and patients with APAP overdose, analyzed liver tissue and bile by mass spectrometry and MALDI-mass spectrometry imaging, assessed the integrity of the blood-bile barrier and the role of oxidative stress by immunostaining of tight junction proteins and intravital imaging of fluorescent markers, identified the intracellular cytotoxic concentrations of BAs, and performed interventions to block BA uptake from blood into hepatocytes.ResultsPrior to the onset of cell death, APAP overdose causes massive oxidative stress in the pericentral lobular zone, which coincided with a breach of the blood-bile barrier. Consequently, BAs leak from the bile canaliculi into the sinusoidal blood, which is then followed by their uptake into hepatocytes via the basolateral membrane, their secretion into canaliculi and repeated cycling. This, what we termed 'futile cycling' of BAs, led to increased intracellular BA concentrations that were high enough to cause hepatocyte death. Importantly, however, the interruption of BA re-uptake by pharmacological NTCP blockage using Myrcludex B and Oatp knockout strongly reduced APAP-induced hepatotoxicity.ConclusionsAPAP overdose induces a breach of the blood-bile barrier which leads to futile BA cycling that causes hepatocyte death. Prevention of BA cycling may represent a therapeutic option after APAP intoxication.Lay summaryOnly one drug, N-acetylcysteine, is approved for the treatment of acetaminophen overdose and it is only effective when given within ∼8 hours after ingestion. We identified a mechanism by which acetaminophen overdose causes an increase in bile acid concentrations (to above toxic thresholds) in hepatocytes. Blocking this mechanism prevented acetaminophen-induced hepatotoxicity in mice and evidence from patients suggests that this therapy may be effective for longer periods after ingestion compared to N-acetylcysteine.
| S-EPMC9209783 | biostudies-literature
Project description:Acetaminophen (APAP) is the most commonly used over-the-counter analgesic. However, hepatotoxicity induced by APAP is a major clinical issue, and the factors that define sensitivity to APAP remain unclear. We have previously demonstrated that mice nulled for glutathione S-transferase Pi (GSTP) are resistant to APAP-induced hepatotoxicity. This study aims to exploit this difference to delineate pathways of importance in APAP toxicity. We used mice nulled for GSTP and heme oxygenase-1 oxidative stress reporter mice, together with a novel nanoflow liquid chromatography-tandem mass spectrometry methodology to investigate the role of oxidative stress, cell signaling, and protein S-glutathionylation in APAP hepatotoxicity. We provide evidence that the sensitivity difference between wild-type and Gstp1/2(-/-) mice is unrelated to the ability of APAP to induce oxidative stress, despite observing significant increases in c-Jun N-terminal kinase and extracellular signal-regulated kinase phosphorylation in wild-type mice. The major difference in response to APAP was in the levels of protein S-glutathionylation: Gstp1/2(-/-) mice exhibited a significant increase in the number of S-glutathionylated proteins compared with wild-type animals. Remarkably, these S-glutathionylated proteins are involved in oxidative phosphorylation, respiratory complexes, drug metabolism, and mitochondrial apoptosis. Furthermore, we found that S-glutathionylation of the rate-limiting glutathione-synthesizing enzyme, glutamate cysteine ligase, was markedly increased in Gstp1/2(-/-) mice in response to APAP. The data demonstrate that S-glutathionylation provides an adaptive response to APAP and, as a consequence, suggest that this is an important determinant in APAP hepatotoxicity. This work identifies potential novel avenues associated with cell survival for the treatment of chemical-induced hepatotoxicity.
| S-EPMC4631951 | biostudies-literature
Project description:Acetaminophen (APAP) overdose is one of the most frequent causes of acute liver failure in the United States and is primarily mediated by toxic metabolites that accumulate in the liver upon depletion of glutathione stores. However, cells of the innate immune system, including natural killer (NK) cells, neutrophils, and Kupffer cells, have also been implicated in the centrilobular liver necrosis associated with APAP. We have recently shown that dendritic cells (DCs) regulate intrahepatic inflammation in chronic liver disease and, therefore, postulated that DC may also modulate the hepatotoxic effects of APAP. We found that DC immune-phenotype was markedly altered after APAP challenge. In particular, liver DC expressed higher MHC II, costimulatory molecules, and Toll-like receptors, and produced higher interleukin (IL)-6, macrophage chemoattractant protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-?). Conversely, spleen DC were unaltered. However, APAP-induced centrilobular necrosis, and its associated mortality, was markedly exacerbated upon DC depletion. Conversely, endogenous DC expansion using FMS-like tyrosine kinase 3 ligand (Flt3L) protected mice from APAP injury. Our mechanistic studies showed that APAP liver DC had the particular capacity to prevent NK cell activation and induced neutrophil apoptosis. Nevertheless, the exacerbated hepatic injury in DC-depleted mice challenged with APAP was independent of NK cells and neutrophils or numerous immune modulatory cytokines and chemokines.Taken together, these data indicate that liver DC protect against APAP toxicity, whereas their depletion is associated with exacerbated hepatotoxicity.
| S-EPMC3166555 | biostudies-literature