Raf Kinase Inhibitory Protein Down-Expression Exacerbates Hepatic Fibrosis In Vivo and In Vitro

Network Pharmacology and Molecular Docking Reveal the Mechanism of Isodon ternifolius (D. Don) Kudo Against Liver Fibrosis

Aim

Many studies have demonstrated the hepatoprotective or anti-fibrotic effects of Isodon ternifolius, but its pharmacological basis and mechanism remain unclear. In this study, we used in vitro models to validate the predicted results and revealed the potential mechanism of action and active ingredients through network pharmacology methods and molecular docking.

Methods

The chemical components of Isodon ternifolius were identified by literatures. Potential targets of Isodon ternifolius were predicted by Swiss Target Prediction. The disease targets were collected through the databases of Gene Card. Common targets of Isodon ternifolius and liver fibrosis were obtained by online tool Venny 2.1. PPI protein interaction network was obtained using String database, and target protein interaction network was drawn using Cytoscape software. Signaling pathway enrichment analysis was performed on drug-disease targets with of DAVID database.

Results

Twenty-one potential active ingredients and 298 potential targets were predicted by Swiss Target Prediction platform. Ninety pathways related to liver fibrosis were obtained by KEGG enrichment. The TLR4, MAPK and PI3K-Akt signaling pathways are mostly associated with liver fibrosis. Molecular docking techniques were used to validate the core target proteins TNF, Akt1, MAPK1, EGFR and TLR4 binding to the ingredients of Isodon ternifolius, which showed that a multitude of ingredients of Isodon ternifolius were able to bind to the above target proteins, especially 2α-hydroxy oleanolic acid and (-)-Lambertic acid. Our experimental validation results showed that Isodon ternifolius inhibited the activation of PI3K-Akt and ERK1/2 signaling pathways.

Conclusion

Through a network pharmacology approach and in vitro cell assay, we predicted and validated the active compounds of Isodon ternifolius and its potential targets for LF treatment. The results suggest that the mechanism of Isodon ternifolius treating LF by inhibiting angiogenesis may be related to the ERK1/2 and PI3K/Akt signaling pathways.

Blocking C-Raf alleviated high-dose small-volume radiation-induced epithelial mesenchymal transition in mice lung

The goal of this study was to develop a potential druggable target for lung injury after SABR through the small animal model. Utilising the model, a radiation dose of 70 Gy or 90 Gy was focally (small volume) delivered to the left lung of mice. The highly expressed phosphorylation form of C-Raf was discovered through a protein array experiment, with the protein being extracted from the area of radiated mouse lung tissue, and was confirmed by IHC and western blot. C-Raf activation, along with morphological change and EMT (Epithelial to Mesenchymal Transition) marker expression, was observed after radiation to the mouse type II alveolar cell line MLE-12. C-Raf inhibitor GW5074 was able to reverse the EMT in cells effectively, and was found to be dependent on Twist1 expression. In the animal experiment, pretreatment of GW5074 alleviated EMT and lung injury after 70 Gy radiation was focally delivered to the lung of mice. Conclusively, these results demonstrate that C-Raf inhibitor GW5074 inhibits high-dose small-volume radiation-induced EMT via the C-Raf/Twist1 signalling pathway in mice. Therefore, pharmacological C-Raf inhibitors may be used effectively as inhibitors of SABR-induced lung fibrosis.

Platycodin D alleviates liver fibrosis and activation of hepatic stellate cells by regulating JNK/c-JUN signal pathway

Liver fibrosis is involved in the progression of most chronic liver diseases. Even though we have made a huge progress in order to understand the pathogenesis of liver fibrosis, however, there is still a lack of productive treatments. Being a traditional Chinese medicine, Platycodin D (PD), an oleanane kind of triterpenoid saponin has been put to extensive use for treating different kinds of illnesses that include not just anti-nociceptive, but also antiviral, anti-inflammatory, and anti-cancer for thousands of years. Nonetheless, there has been no clarification made for its effects on the progression of liver fibrosis. In this manner, we carried out in vitro studies for the purpose of investigating the anti-fibrosis impact of PD. Activation of hepatic stellate cells was evaluated by means of the detection of the proliferation of HSCs and the expression of specific proteins. We discovered the fact that PD had the potential of activating HSCs. Thereafter, we detected the apoptosis and autophagy of the HSCs; as the results suggested, PD induced apoptosis and autophagy of the HSCs. It augmented the expression level of apoptotic proteins that included Bax, Cytochrome C (cyto-c), cleaved caspase3 and cleaved caspase9, in addition to the autophagy relevant proteins, for instance, LC3II, beclin1, Atg5 and Atg9. Further research was carried out for the investigation of the underlying molecular mechanism, and discovered that PD promoted the phosphorylation of JNK and c-Jun. Treating the JNK inhibitor P600125 inhibited the effect of PD, confirming the impact of PD on the regulation of JNK/c-Jun pathway. Thus, we speculated that PD alleviates liver fibrosis and activation of hepatic stellate via promoting phosphorylation of JNK and c-Jun and further altering the autophagy along with apoptosis of HSCs.

Liver Fibrosis and Inflammation under the Control of ERK2

Chronic liver injury could lead the formation of liver fibrosis, eventually some would develop to hepatocellular carcinoma (HCC), one of the leading malignancies worldwide. The aim of the study is to dissect the role of extracellular signal-regulated kinase 2 (ERK2) signaling in liver fibrosis and inflammation. The choline-deficient, ethionine-supplemented (CDE) diet could lead to fatty livers and generate oval cells, activate hepatocyte stellate cell (HSC) and recruit immune cells as the liver fibrosis model mice. WT and ERK2 deficient (ERK2^−/−) mice were compared in terms of liver weight/body weight, liver function, liver fibrosis markers and the differential gene expression in hepatotoxicity. ERK2^−/− mice display the less degree of liver fibrosis when compared to WT mice. The protein level of alpha smooth muscle (α-SMA) was reduced and several hepatocellular carcinoma-related genes such as MMP9, FoxM1 were down-regulated. In addition, the cell proliferation and the percentages of activated T cells were reduced in ERK2^−/− mice upon liver injury. Therefore, ERK2 plays an important role in regulating liver cirrhosis and inflammation.

PEBP1/RKIP behavior: a mirror of actin-membrane organization

Phosphatidylethanolamine-binding protein 1 (PEBP1), a small 21 kDa protein, is implicated in several key processes of the living cell. The deregulation of PEBP1, especially its downregulation, leads to major diseases such as cancer and Alzheimer's disease. PEBP1 was found to interact with numerous proteins, especially kinases and GTPases, generally inhibiting their activity. To understand the basic functionality of this amazing small protein, we have considered several known processes that it modulates and we have discussed the role of each molecular target in these processes. Here, we propose that cortical actin organization, associated with membrane changes, is involved in the majority of the processes modulated by PEBP1. Furthermore, based on recent data, we summarize some key PEBP1-interacting proteins, and we report their respective functions and focus on their relationships with actin organization. We suggest that, depending on the cell status and environment, PEBP1 is an organizer of the actin-membrane composite material.

Locostatin Alleviates Liver Fibrosis Induced by Carbon Tetrachloride in Mice

BACKGROUND AND AIMS

Liver fibrosis is featured with excessive deposition of extracellular matrix and fibrous connective tissue hyperplasia. The specific inhibitor of Raf-1 kinase inhibitor protein, locostatin, inhibits the migration of hepatic stellate cells. In this study, we investigated the effect of locostatin on liver fibrosis and its underlying mechanism.

METHODS

Carbon tetrachloride (CCl4) was used to induce liver fibrosis in mice, and locostatin was injected intraperitoneally. Liver fibrosis was assessed by Masson and Sirius red staining, hydroxyproline (HYP) assay, and collagen percentage area. Collagen I, collagen III, and α-SMA were detected by RT-PCR and western blot. The levels of MMP-13, MMP-2, TIMP-1, and TIMP-2 were estimated by ELISA. Liver inflammation was evaluated by HE staining and immunohistochemistry; liver myeloperoxidase (MPO), superoxide dismutase, and malondialdehyde were measured by ELISA; and cytokines were by Mouse Cytokine Array Q4000.

RESULTS

Compared to the CCl4 group, HYP (208.56 ± 6.12) µg/g, percentage of total collagen at overall region (1.91 ± 0.13), MMP-13/TIMP-1 (0.19 ± 0.01), MPO (1.45 ± 0.04) U/g, TGF-β (2652 ± 91.20), PDGF-AA (3897 ± 290.69), and E-selectin (1569 ± 66.48) in the liver tissues were decreased significantly in the locostatin-treated group.

CONCLUSIONS

Locostatin mitigated liver fibrosis and inflammation induced by CCl4. The mechanism is via inhibition inflammatory cytokines, TGF-β, PDGF-AA, and E-selectin.

Methyl helicterilate ameliorates alcohol-induced hepatic fibrosis by modulating TGF-β1/Smads pathway and mitochondria-dependent pathway

This study aimed to investigate the effect and underlying mechanism of Methyl helicterilate from Helicteres angustifolia (MHHA) on alcohol-induced hepatic fibrosis. The results showed that MHHA treatment markedly alleviated alcohol-induced liver injury and notably reduced collagen deposition in liver tissue. It significantly enhanced the activity of alcohol dehydrogenase and aldehyde dehydrogenase. Moreover, MHHA treatment markedly decreased the content of inflammatory cytokines, alleviated collagen accumulation, and inhibited the expression of TGF-β1 and Smad2/3 in liver tissue. The experiments in cells showed that MHHA significantly inhibited HSC activation by blocking TGF-β1/Smads signaling pathway. Additionally, it notably induced HSC apoptosis by modulating the mitochondria-dependent pathway. The present study demonstrates that MHHA treatment significantly ameliorates alcoholic hepatic fibrosis and the underlying mechanism may be ascribed to the inhibition of the TGF-β1/Smads pathway and regulation of the mitochondria-mediated apoptotic pathway.

ERK Pathway in Activated, Myofibroblast-Like, Hepatic Stellate Cells: A Critical Signaling Crossroad Sustaining Liver Fibrosis

Fibrogenic progression of chronic liver disease, whatever the etiology, is characterized by persistent chronic parenchymal injury, chronic activation of inflammatory response, and sustained activation of liver fibrogenesis, and of pathological wound healing response. A critical role in liver fibrogenesis is played by hepatic myofibroblasts (MFs), a heterogeneous population of α smooth-muscle actin—positive cells that originate from various precursor cells through a process of activation and transdifferentiation. In this review, we focus the attention on the role of extracellular signal-regulated kinase (ERK) signaling pathway as a critical one in modulating selected profibrogenic phenotypic responses operated by liver MFs. We will also analyze major therapeutic antifibrotic strategies developed in the last two decades in preclinical studies, some translated to clinical conditions, designed to interfere directly or indirectly with the Ras/Raf/MEK/ERK signaling pathway in activated hepatic MFs, but that also significantly increased our knowledge on the biology and pathobiology of these fascinating profibrogenic cells.