Kaempferol induces hepatocellular carcinoma cell death via endoplasmic reticulum stress-CHOP-autophagy signaling pathway Kaempferol induces hepatocellular carcinoma cell death via endoplasmic reticulum stress-CHOP-autophagy signaling pathway

Endoplasmic reticulum stress (ER stress) just like a double-edged sword depending on different conditions in the development of multiple hepatic diseases. But the molecular mechanisms of functional conversion during ER stress have not been fully elucidated. In this study, we aim to illustrate the role of PPARα and the subtle mechanism in the functional conversion of ER stress. Tunicamycin (TM) and thapsigargin (TG), as ER stress inducers, were used to induce ER stress in AML12 cells. During the ER stress, qRT-PCR and immunoblotting was used to measure the expression levels of GRP78 and CHOP which show a gradually increasing trend, while PPARα and autophagy was significantly activated in the early stage but was inhibited in the late stage. Moreover, PPARα inhibition by siRNA promoted cell injury in the mild-ER stress and PPARα activation by WY-14643 reduced cell apoptosis in the serious ER stress. In the mild-ER stress with PPARα knocked down, activation of autophagy by rapamycin significantly improved cell survival, in the serious ER stress with PPARα activation, inhibition of autophagy by 3-MA aggravate cell injury. In addition, in the mild-ER stress with PPARα knocked down, CHOP knocked down by siRNA reduced cell apoptosis, in the serious ER stress activated PPARα, CHOP over-expression mediated by lentiviral vector contributed to serious cell injury. Furthermore, C57BL/6 mice was used to induce ER stress with TM intraperitoneal injection, PPARα and autophagy was upregulated in the mild-ER stress while downregulated in the serious ER stress, measured by qRT-PCR and immunoblotting, further confirmed the finding in vitro. Our results firstly demonstrated that PPARα is a key molecule in the functional conversion of ER stress: protective effects in the mild ER stress was mediated by PPARα-autophagy pathway and destructive effects in the serious ER stress was mediated by PPARα-CHOP pathway.

Context: Acute liver failure is a serious disease caused by a variety of factors, and immunological injury is an important pathological process. Comprehensive liver treatment efficacy is poor, and the mortality rate is high.Magnesium isoglycyrrhizinate (MgIG) is a new glycyrrhizin drug extracted from the traditional Chinese medicine licorice. The mechanism by which MgIG regulates ConcanavalinA (ConA)-induced immunological liver injuryin mice is not completely clear. Objective: Materials and methods: Immunological liver injury was induced in mice by ConA injection, and the inflammatory macrophages model was induced by lipopolysaccharide (LPS). MgIG was administered 30 min prior to ConAand LPS treatment. The mice in the differentgroups were sacrificed 12 h after treatment, and macrophages were measured at 30min, 1h and 2h after induction. Macrophages, liver and blood samples were then collected foranalysis. Results: After drug administration, the MgIG group showed a marked decrease in serumtransaminaselevels, reducedapoptosis and hepatic inflammatory responses compared to the ConA group. Furthermore, there was a significant reduction ininflammatory cytokine levels in the serum and liver tissue.In vitro, the expression of inflammatory cytokines wasdistinctlyreduced after MgIG administration. In addition, MgIG pretreatment reduced the expression of inflammatory cytokines and regulated the phosphorylation of p38 and JNK proteins in the MAPK pathway. Conclusion: These findings demonstrated that MgIG protects against ConA-induced immunological liver injury by markedly alleviating liver inflammation, and this provides guidance for the clinical amelioration of liver inflammation induced by immunological factors.

Caspase-1 is an evolutionarily conserved enzyme that proteolytically cleaves the precursors of the inflammatory cytokines interleukin 1β and interleukin 18. However, the role of caspase-1 in determining the severity of acute-on-chronic liver failure (ACLF) has yet to be elucidated. We evaluated the expression levels of caspase-1 in HBV-related liver disease and assessed its utility as a biomarker predicting the severity of ACLF. The gene, protein and activity levels of caspase-1 were measured in the liver and/or serum of subjects with HBV-related disease. We also analysed the correlation between the expression levels of caspase-1 and liver injury of ACLF. Compared with the values observed in normal subjects, the relative caspase-1 mRNA and protein levels in livers were decreased in patients with CHB, LC, and HCC but increased in those with ACLF; moreover, ACLF patients had the lowest serum level and hepatic activity of caspase-1 among the five groups. The serum caspase-1 levels in ACLF patients showed a negative correlation with total serum bilirubin and a positive correlation with serum total protein and albumin. Importantly, the serum caspase-1 levels in the surviving group with ACLF were higher than those in the non-surviving group and showed different dynamic trends. Analyses of the area under the receiver operating characteristic curve indicated that caspase-1 (AUC = 0.84, AUC of MELD score = 0.72) may be a useful marker for independently predicting ACLF. Caspase-1 is a potential non-invasive biomarker of disease progression and prognosis in ACLF.

Acetaminophen (APAP) overdose induces hepatocyte necrosis and causes liver hepatotoxicity. Currently, the role of galactosyltransferase in APAP-induced liver injury is still unclear. This study assessed the contribution of the GLT25D2 gene, a kind of collagen galactosyltransferase, to the development of APAP-induced liver injury. This study found that the expression of GLT25D2 markedly increased first and then decreased in the liver of mice treated with APAP, however, it downregulated in the liver of APAP overdose-patients compared with normal controls. Knockout of GLT25D2 significantly ameliorated the liver injury, meanwhile, it downregulated the proinflammatory cytokines (IL-6, TNF-α) and chemokines (CXCL-10, MIG and CXCL-1) levels, however, and upregulated the anti-inflammatory cytokines (IL-22, IL-10) levels. Mechanistic explorations showed that (1) GLT25D2 knockout promoted autophagy pathway; and (2) the GLT25D2 knockout-induced autophagy selected to clear damaged mitochondria in APAP-induced liver injury by mitophagy; and (3) the autophagy intervention by Atg 7 siRNA cancelled liver protection by knockout of GLT25D2 through regulating liver inflammation. In conclusion, our study proves that the upregulated expression of GLT25D2 decreased autophagy contributing to APAP-induced hepatotoxicity by mediating the inflammatory immune regulatory mechanism.