Gamma-linolenic acid inhibits hepatic PAI-1 expression by inhibiting p38 MAPK-dependent activator protein and mitochondria-mediated apoptosis pathway

The Landscape of Using Glycosyltransferase Gene Signatures for Overall Survival Prediction in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a heterogeneous disease that occurs in the setting of chronic liver diseases. The role of glycosyltransferase (GT) genes has recently been the focus of research associated with tumor development. However, the prognostic value of GT genes in HCC remains unclear. Therefore, this study aimed to identify GT genes related to HCC prognosis through bioinformatics analysis. We firstly constructed a prognostic signature based on four GT genes using univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses in The Cancer Genome Atlas (TCGA) dataset. Next, the risk score of each patient was calculated, and HCC patients were divided into high- and low-risk groups. Kaplan–Meier analysis showed that the survival rate of high-risk patients was significantly lower than that of low-risk patients. Receiver operating characteristic (ROC) curves assessed that risk scores calculated with a four-gene signature could predict 3- and 5-year overall survival (OS) of HCC patients, revealing the prognostic ability of this gene signature. Moreover, univariate and multivariate Cox regression analyses demonstrated that the risk score was an independent prognostic factor of HCC. Finally, functional analysis revealed that immune-related pathways were enriched and the immune status was different between the two risk groups in HCC. In summary, the novel GT gene signature could be used for prognostic prediction of HCC. Thus, targeting the GT genes may serve as an alternative treatment strategy for HCC.

A basal level of γ-linolenic acid depletes Ca2+ stores and induces endoplasmic reticulum and oxidative stresses to cause death of breast cancer BT-474 cells

Gamma-linolenic acid (GLA), a natural fatty acid obtained from oils of various vegetables and seeds, has been demonstrated as an anticancer agent. In this work, we investigated the anticancer effects of GLA on breast cancer BT-474 cells. GLA at 30 μM, a concentration reportedly within the range of circulating concentrations in clinical studies, caused apoptotic cell death. GLA caused an elevation in mitochondrial Ca²⁺ level and a decrease in mitochondrial membrane potential. GLA treatment depleted cyclopiazonic acid (CPA)-sensitive Ca²⁺ store and triggered substantial Ca²⁺ influx. Intracellular Ca²⁺ release triggered by GLA was suppressed by 3 μM xestospongin C (XeC, IP₃ receptor-channel blocker) and 100 μM ryanodine (ryanodine receptor-channel blocker), suggesting that the Ca²⁺ release was via IP₃ receptor-channel and ryanodine receptor-channel. Increased expressions of p-eIF2α and CHOP were observed in GLA-treated cells, suggesting GLA-treated cells had increased expressions of p-eIF2α and CHOP, which suggest endoplasmic reticulum (ER) stress. In addition, GLA elicited increased production of reactive oxygen species. Taken together, our results suggest a basal level of GLA induced apoptotic cell death by causing Ca²⁺ overload, mitochondrial dysfunction, Ca²⁺ store depletion, ER stress, and oxidative stress. This is the first report to show that GLA caused Ca²⁺ store depletion and ER stress. GLA-induced Ca²⁺ store depletion resulted from opening of IP₃ receptor-channel and ryanodine receptor-channel.

Pomolic Acid Ameliorates Fibroblast Activation and Renal Interstitial Fibrosis through Inhibition of SMAD-STAT Signaling Pathways

Fibrosis is a common pathological feature in most kinds of chronic kidney disease. Transforming growth factor β1 (TGF-β1) signaling is the master pathway regulating kidney fibrosis pathogenesis, in which mothers against decapentaplegic homolog 3 (SMAD3) with signal transducer and activator of transcription 3 (STAT3) act as the integrator of various pro-fibrosis signals. We examine the effects of pomolic acid (PA) on mice with unilateral ureteral obstruction (UUO) and TGF-β1 stimulated kidney fibroblast cells. UUO mice were observed severe tubular atrophy, and tubulointerstitial fibrosis and extracellular matrix (ECM) deposition at seven days postoperatively. However, PA-treated UUO mice demonstrated only moderate injury, minimal fibrosis, and larger reductions in the expression of ECM protein and epithelial-mesenchymal transition (EMT) progress. PA inhibited the SMAD-STAT phosphorylation in UUO mice. PA effects were also confirmed in TGF-β1 stimulated kidney fibroblast cells. In this study, we first demonstrated that PA ameliorates fibroblast activation and renal interstitial fibrosis. Our results indicate that PA may be useful as a potential candidate in the prevention of chronic kidney disease.

Asiatic acid attenuates methamphetamine-induced neuroinflammation and neurotoxicity through blocking of NF-kB/STAT3/ERK and mitochondria-mediated apoptosis pathway

Background

Methamphetamine (METH) is a commonly abused drug that may result in neurotoxic effects. Recent studies have suggested that involvement of neuroinflammatory processes in brain dysfunction is induced by misuse of this drug. However, the mechanism underlying METH-induced inflammation and neurotoxicity in neurons is still unclear. In this study, we investigated whether asiatic acid (AA) effected METH-mediated neuroinflammation and neurotoxicity in dopaminergic neuronal cells. And we further determined whether the effect involved in the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and signal transducer and activator of transcription (STAT)3 and extracellular signal-regulated kinase (ERK) pathway.

Methods

We used the human dopaminergic neuroblastoma SH-SY5Y cell line, murine microglial BV2 cell line, and primary culture of rat embryo mesencephalic neurons. Pro-inflammatory cytokine production was monitored by ELISA and RT/real-time PCR. The cell cycle distribution and mitochondrial membrane integrity was analyzed by flow cytometry. We used immunoblotting, DNA-binding activity, and immunofluorescence staining to analyze the effect of AA on activation of the NF-κB, STAT3, MAPK-ERK, and apoptosis signaling pathways.

Results

METH induced TNF receptor (TNFR) expression and led to morphological changes of cells. Additionally, this drug increased pro-inflammatory cytokine (TNFα and IL-6) expression. AA significantly suppressed METH-induced TNFR expression in concentration dependent. Increased secretion of TNFα and IL-6 was inhibited in METH-stimulated neuronal cells by AA administration. AA showed significant protection against METH-induced translocation of NF-κB/STAT3 and ERK phosphorylation. AA inhibited METH-induced proteolytic fragmentation of caspase-3 and PARP. The pro-apoptotic protein Bax was significantly decreased, while the anti-apoptotic protein Bcl-xL was increased by AA treatment in METH-stimulated cells. A similar protective effect of AA on mitochondrial membrane integrity was also confirmed by flow cytometry and immunofluorescence staining.

Conclusions

Based on the literatures and our findings, AA is a promising candidate for an anti-neurotoxic agent, and it can potentially be used for the prevention and treatment of various neurological disorders.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-1009-0) contains supplementary material, which is available to authorized users.

Preconditioning with melatonin improves therapeutic outcomes of bone marrow-derived mesenchymal stem cells in targeting liver fibrosis induced by CCl4

Preconditioning of mesenchymal stem cells (MSCs) with melatonin (MT) has shown promising results in animal models of myocardial infarction, renal ischemia and cerebral ischemia. Here, we use this strategy in the liver fibrosis induced by CCl4. There were five groups: normal, CCl4, CCl4 + vehicle, CCl4 + BMMSCs and CCl4 + MT-bone marrow (BM)-derived MSCs (MT-BMMSCs). CCl4 was injected twice weekly for 8 weeks and treatment either with cells or vehicle was performed at the beginning of week 5 with a single dose. BMMSCs were preconditioned with MT for 24 h before injection. MT-BMMSCs had a high ability of homing into the injured liver (P ≤ 0.05 vs. BMMSCs). The CCl4 + MT-BMMSCs group showed higher percentage of glycogen storage but lower percentage of collagen and lipid accumulation (P ≤ 0.05 vs. CCl4 + BMMSCs). The CCl4 + MT-BMMSCs group showed lower expressions of transforming growth factor-β1 (TGF-β1) and Bax and lower content of sera alanine aminotransferase (ALT) but higher expressions of matrix metalloproteinases (MMPs) and Bcl2 compared with the BMMSCs group (P ≤ 0.05). The results showed the better therapeutic outcomes of MT preconditioning by probably improving cell homing and also better maintenance of the balance between matrix degrading and accumulating factors.

Suppression of Hepatic Epithelial-to-Mesenchymal Transition by Melittin via Blocking of TGFβ/Smad and MAPK-JNK Signaling Pathways

Transforming growth factor (TGF)-β1 plays a crucial role in the epithelial-to-mesenchymal transition (EMT) in hepatocytes and hepatic stellate cells (HSC), which contributes to the pathogenesis of liver fibrosis. Melittin (MEL) is a major component of bee venom and is effective in rheumatoid arthritis, pain relief, cancer cell proliferation, fibrosis and immune modulating activity. In this study, we found that MEL inhibits hepatic EMT in vitro and in vivo, regulating the TGFβ/Smad and TGFβ/nonSmad signaling pathways. MEL significantly inhibited TGF-β1-induced expression of EMT markers (E-cadherin reduction and vimentin induction) in vitro. These results were confirmed in CCl₄-induced liver in vivo. Treatment with MEL almost completely blocked the phosphorylation of Smad2/3, translocation of Smad4 and phosphorylation of JNK in vitro and in vivo. Taken together, these results suggest that MEL suppresses EMT by inhibiting the TGFβ/Smad and TGFβ/nonSmad-c-Jun N-terminal kinase (JNK)/Mitogen-activated protein kinase (MAPK) signaling pathways. These results indicated that MEL possesses potent anti-fibrotic and anti-EMT properties, which may be responsible for its effects on liver diseases.