Tracking anti‐fibrotic pathways of nilotinib and imatinib in experimentally induced liver fibrosis: An insight

The tyrosine kinase inhibitors imatinib and nilotinib have been suggested to have promising antifibrotic activity in experimental models of liver fibrosis. The aim of the present study was to investigate new pathways underlying this beneficial effect. Hepatic injury was induced in male Wistar rats by intraperitoneal injection of CCl₄ for 12 weeks. During the last 8 weeks of treatment, rats were also injected daily intraperitoneally with 20 mg/kg imatinib or 20, 10 or 5 mg/kg nilotinib. At the end of treatment, effects on fibrosis were assessed by measuring serum fibrotic markers and profibrogenic cytokines, as well as by histopathological examination. Possible anti‐inflammatory effects were estimated by measuring levels of inflammatory cytokines in liver tissue. Liver expression of α‐smooth muscle actin, transforming growth factor (TGF)‐β1 antibodies and platelet‐derived growth factor receptor β (PDGFRβ) was evaluated by immunohistochemical staining techniques. Nilotinib (5 and 10 mg/kg) significantly (P < 0.05) decreased all serum fibrotic markers measured, but 20 mg/kg of either nilotinib or imatinib had limited effects. At all doses tested, nilotinib significantly (P < 0.05) decreased the CCl₄‐induced increases in tissue inflammatory cytokines. Furthermore, 5 and 10 mg/kg nilotinib significantly decreased TGF‐β1 levels and tissue expression of its antibody, as well expression of PDGFRβ. In conclusion, low doses (5 and 10 but not 20 mg/kg) of nilotinib, rather than imatinib, can control hepatic fibrosis by regulating levels of proinflammatory cytokines, primarily interleukin (IL)‐1 and IL‐6. Nilotinib also controls the signalling pathways of profibrogenic cytokines by lowering TGF‐β1 levels and decreasing expression of PDGFRβ.     

Deleterious effects of non‐synonymous single nucleotide variants of human IL‐1β gene

The IL‐1β gene is currently topic of interest for its important role in the pathogenesis of intervertebral disk degeneration. The new sequencing technology makes it crucial to study the effects of variants in IL‐1β. Thus, 714 IL‐1β variants with evidence supporting were collected from the EMBL database. Among them, 62 were non‐synonymous single nucleotide variants (nsSNVs). Furthermore, six common nsSNVs were predicted to have damaging effects by SIFT, PolyPhen, PROVEAN and SNPs&GO. Based on the constructed three‐dimensional structure of pro‐IL‐1β, rs375479974 with a mutation of Phe to Ser was proposed to reduce the stability of the pro‐IL‐1β protein. The rs375479974 variant was found to cause least common stabilizing amino acid residues, decrease hydrophilic and increase hydrophobic surface areas in the greatest degree, and have the lowest free energy alterations in I‐Mutant 2.0 sequence analysis. When analyzing the interaction between the experimental 3D structure of mature IL‐1β and its neutralizing McAb canakinumab complex, the rs775174784 substitution of Leu with Phe was found to attenuate this interaction by reducing binding energy, while rs375479974 not. Molecular dynamics simulation results in intervertebral disk environment supported rs775174784's effects. These results suggest that both rs375479974 and rs775174784 may have potential clinical and drug target implications.     

5‐Amino‐3‐methyl‐4‐isoxazolecarboxylic acid hydrazide derivatives with in vitro immunomodulatory activities

Isoxazoles are an important class of compounds of potential therapeutic value. The aim of this study was to determine immunotropic effects of 5‐amino‐3‐methyl‐4‐isoxazolecarboxylic acid hydrazide derivatives on spontaneous and mitogen‐induced lymphocyte proliferation in young and old mice, cytokine production by peritoneal cells as well as possible mechanism of action in a model of Jurkat cells. Three‐month‐old and 13‐month‐old BALB/c mice were used as donors of the cells from a thymus, a spleen, mesenteric lymph nodes, and a peritoneal cavity. Spontaneous and concanavalin A or lipopolysaccharide (LPS)‐induced cell proliferation was measured by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide colorimetric method. IL‐1β and TNF‐α production induced by LPS in macrophage‐enriched peritoneal cell cultures was measured by enzyme‐linked immunoassay. 5‐amino‐3‐methyl‐4‐isoxazolecarboxylic acid hydrazide, 01K (4‐phenyl‐1‐(5‐amino‐3‐methylisoxazole‐4‐carbonyl)‐thiosemicarbazide), and 06K (4‐(4‐chlorophenyl)‐1‐(5‐amino‐3‐methylisoxazole‐4‐carbonyl)‐thiosemicarbazide) exhibited regulatory activity in the proliferation tests. Prevailing stimulatory activity of the hydrazide and inhibitory activity of 01K and 06K was observed. Those effects were connected with different influence of the compounds on signaling proteins expression in Jurkat cells. The regulatory effects of the compounds on IL‐1β production were more profound than those on TNF‐α. Differences in the compound activity in young versus old mice were mainly restricted to 01K. Immunosuppressive isoxazole leflunomide and a stimulatory RM‐11 (1,7‐dimethyl‐8‐oxo‐1,2H‐isoxazole [5,4‐e]triazepine) were applied as reference drugs.     

Circulating microRNA 122 in the methionine and choline‐deficient mouse model of non‐alcoholic steatohepatitis

Non‐alcoholic steatohepatitis (NASH) is a progressive form of non‐alcoholic fatty liver disease (NAFLD) and is a major cause of liver cirrhosis and hepatic failure. The methionine choline‐deficient diet (MCD) is a frequently used hepatotoxicity animal model of NASH that induces hepatic transaminase (ALT, AST) elevations and hepatobiliary histological changes similar to those observed in human NASH. Liver‐specific microRNA‐122 (miR‐122) has been shown as a key regulator of cholesterol and fatty acid metabolism in adult liver, and has recently been proposed as a sensitive and specific circulating biomarker of hepatic injury. The purpose of this study was to assess miR‐122 serum levels in mice receiving an MCD diet for 0, 3, 7, 14, 28 and 56 days and compare the performance vs. routine clinical chemistry when benchmarked against the histopathological liver findings. MiR‐122 levels were quantified in serum using RT‐qPCR. Both miR‐122 and ALT/AST levels were significantly elevated in serum at all timepoints. MiR‐122 levels increased on average by 40‐fold after 3 days of initiating the MCD diet, whereas ALT and AST changes were 4.8‐ and 3.3‐fold, respectively. In general, miR‐122 levels remained elevated across all time points, whereas the ALT/AST increases were less robust but correlated with the progressive severity of NASH as assessed by histopathology. In conclusion, serum levels of miR‐122 can potentially be used as a sensitive biomarker for the early detection of hepatotoxicity and can aid in monitoring the extent of NAFLD‐associated liver injury in mouse efficacy models. Copyright © 2013 John Wiley & Sons, Ltd.     

Convenient and efficient synthesis of Boc‐/Z‐/Fmoc‐β‐amino acids employingN‐protected α‐amino acid fluorides

Abstract: A new and efficient method for the synthesis ofN^α‐Fmoc‐/Boc‐/Z‐β‐amino acids using the two‐step Arndt‐Eistert approach is described. Fmoc‐/Boc‐/Z‐α‐Amino acid fluorides were used for the acylation of diazomethane synthesizing Fmoc‐/Boc‐/Z‐α‐aminodiazoketones as crystalline solids with good yield and purity. They were then converted to the corresponding β‐amino acids using PhCOOAg/dioxane/H₂O.     

Prediction of drug‐induced liver injury using keratinocytes

Drug‐induced liver injury (DILI) is one of the most common adverse drug reactions. DILI is often accompanied by skin reactions, including rash and pruritus. However, it is still unknown whether DILI‐associated genes such as S100 calcium‐binding protein A and interleukin (IL)‐1β are involved in drug‐induced skin toxicity. In the present study, most of the tested hepatotoxic drugs such as pioglitazone and diclofenac induced DILI‐associated genes in human and mouse keratinocytes. Keratinocytes of mice at higher risk for DILI exhibited an increased IL‐1β basal expression. They also showed a higher inducibility of IL‐1β when treated by pioglitazone. Mice at higher risk for DILI showed even higher sums of DILI‐associated gene basal expression levels and induction rates in keratinocytes. Our data suggest that DILI‐associated genes might be involved in the onset and progression of drug‐induced skin toxicity. Furthermore, we might be able to identify individuals at higher risk of developing DILI less invasively by examining gene expression patterns in keratinocytes. Copyright © 2017 John Wiley & Sons, Ltd.     

MiR‐146a regulates PM1‐induced inflammation via NF‐κB signaling pathway in BEAS‐2B cells

Exposure to particulate matter (PM) leads to kinds of cardiopulmonary diseases, such as asthma, COPD, arrhythmias, lung cancer, etc., which are related to PM‐induced inflammation. We have found that PM_2.5 (aerodynamics diameter <2.5 µm) exposure induces inflammatory response both in vivo and in vitro. Since the toxicity of PM is tightly associated with its size and components, PM₁ (aerodynamics diameter <1.0 µm) is supposed to be more toxic than PM_2.5. However, the mechanism of PM₁‐induced inflammation is not clear. Recently, emerging evidences prove that microRNAs play a vital role in regulating inflammation. Therefore, we studied the regulation of miR‐146a in PM₁‐induced inflammation in human lung bronchial epithelial BEAS‐2B cells. The results show that PM₁ induces the increase of IL‐6 and IL‐8 in BEAS‐2B cells and up‐regulates the miR‐146a expression by activating NF‐κB signaling pathway. Overexpressed miR‐146a prevents the nuclear translocation of p65 through inhibiting the IRAK1/TRAF6 expression, and downregulates the expression of IL‐6 and IL‐8. Taken together, these results demonstrate that miR‐146a can negatively feedback regulate PM₁‐induced inflammation via NF‐κB signaling pathway in BEAS‐2B cells.     

Coffee attenuates fibrosis by decreasing the expression of TGF‐β and CTGF in a murine model of liver damage

This study was performed to evaluate the antifibrotic properties of coffee in a model of liver damage induced by repeated administration of thioacetamide (TAA) in male Wistar rats. In this study, cirrhosis was induced by chronic TAA administration and the effects of co‐administration of conventional caffeinated coffee or decaffeinated coffee (CC, DC, respectively) for 8 weeks were evaluated. TAA administration elevated serum alkaline phosphatase (AP), γ‐glutamyl transpeptidase (γ‐GTP) and alanine aminotransferase (ALAT), liver lipid peroxidation, collagen content, depleted liver glycogen and glutathione peroxidase (GPx) activity. Additionally increased levels of a number of proteins were detected including transforming growth factor‐beta (TGF‐β), connective tissue growth factor (CTGF) and alpha‐smooth muscle actin (α‐SMA), and matrix metalloproteinase (MMP)‐2, 9 and 13. Coffee suppressed most of the changes produced by TAA. Histopathological analysis was in agreement with biochemical and molecular findings. These results indicate that coffee attenuates experimental cirrhosis; the action mechanisms are probably associated with its antioxidant properties and mainly by its ability to block the elevation of the profibrogenic cytokine TGF‐β and its downstream effector CTGF. Various components of coffee that have been related to such a favorable effect include caffeine, coffee oils kahweol, cafestol and antioxidant substances; however, no definite evidence for the role of these components has been established. These results support earlier findings suggesting a beneficial effect of coffee on the liver. However, more basic clinical studies must be performed to confirm this hypothesis. Copyright © 2012 John Wiley & Sons, Ltd.     

A role of peroxisome proliferator‐activated receptor γ in non‐alcoholic fatty liver disease

Non‐alcoholic fatty liver disease is becoming a major health burden, as prevalence increases and there are no approved treatment options. Thiazolidinediones target the nuclear receptor peroxisome proliferator‐activated receptor γ (PPARγ) and have been investigated in several clinical trials for their potential in treating non‐alcoholic fatty liver disease (NAFLD) and non‐alcoholic steatohepatitis (NASH). PPARγ has specialized roles in distinct tissues and cell types, and although the primary function of PPARγ is in adipose tissue, where the highest expression levels are observed, hepatic expression levels of PPARγ are significantly increased in patients with NAFLD. Thus, NAFLD patients receiving treatment with PPARγ agonists might have a liver response apart from the one in adipose tissue. Owing to the different roles of PPARγ, new treatment strategies include development of compounds harnessing the beneficial effects of PPARγ while restricting PPARγ unwanted effects such as adipogenesis resulting in weight gain. Furthermore, dual or pan agonists targeting two or more of the PPARs have shown promising results in pre‐clinical research and some are currently proceeding to clinical trials. This MiniReview explores adipose‐ and liver‐specific actions of PPARγ, and how this knowledge may contribute in the search for new treatment modalities in NAFLD/NASH.     

Effects of thalidomide and 3‐phthalimido‐3‐(3,4‐dimethoxyphenyl)‐propanamide on bile duct obstruction‐induced cirrhosis in the rat

Tumor necrosis factor‐alpha (TNF‐α) plays a central role in cellular necrosis, apoptosis, organ failure, tissue damage, inflammation, and fibrosis. These processes, occurring in liver injury, may lead to cirrhosis. Thalidomide and its analogs have shown to be effective TNF‐α inhibitors. The aim of this work was to synthesize a thalidomide analog, the 3‐phthalimido‐3‐(3,4‐dimethoxyphenyl)‐propanamide (PDP) and to evaluate its hepatoprotective properties on bile duct obstruction‐induced cirrhosis. Synthesis, purification, and spectroscopic characterization of PDP were carried out. Thalidomide (200 mg/kg) or PDP (15 mg/kg) were administered to sham (Sh) or bile duct ligated (BDL) rats. The animals were sacrificed 28 days after treatments. Alkaline phosphatase (Alk. Phosph.), γ‐glutamyl transpeptidase (γ‐GTP) and alanine aminotransferase (ALT) enzyme activities, bilirubins, and TNF‐α concentrations were evaluated in plasma. Collagen was estimated by the liver hydroxyproline content and histopathology was performed. Both drugs showed partial amelioration of cirrhosis. However, the hepatoprotective effects of thalidomide were poor when compared to those afforded by PDP. While PDP improved the majority of the biochemical markers of liver injury and prevented partial but significantly collagen accumulation, thalidomide showed only modest beneficial effects on bilirubins and ALT. PDP was effective in preventing the increase in plasma TNF‐α levels, while thalidomide not only failed to inhibit TNF‐α, but increased it. Differences between thalidomide and PDP effectiveness may be due to their stability and different mechanism of action, as reported by others. Inhibition of proinflamatory cytokines is an interesting pharmacological aim to treat cirrhosis. Drug Dev. Res. 54:209–218, 2001. © 2002 Wiley‐Liss, Inc.     

A high‐fat diet and multiple administration of carbon tetrachloride induces liver injury and pathological features associated with non‐alcoholic steatohepatitis in mice

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Lanatoside C protects mice against bleomycin‐induced pulmonary fibrosis through suppression of fibroblast proliferation and differentiation

It has been established that lanatoside C, a FDA‐approved cardiac glycoside, reduces proliferation of cancer cell lines. The proliferation of fibroblasts is critical to the pathogenesis of pulmonary fibrosis (PF), a progressive and fatal fibrotic lung disease lacking effective treatment. In this study we have investigated the impact of lanatoside C on a bleomycin (BLM)‐induced mouse model of PF and through the evaluation of fibroblast proliferation and activation in vitro. We evaluated explanted lung tissue by histological staining, western blot analysis, qRT‐PCR and survival analysis, demonstrating that lanatoside C was able to protect mice against BLM‐induced pulmonary fibrosis. The proliferation of cultured pulmonary fibroblasts isolated from BLM‐induced PF mice was suppressed by lanatoside C, as hypothesized, through the induction of cell apoptosis and cell cycle arrest at the G2/M phase. The Akt signalling pathway was involved in this process. Interestingly, the production of α‐SMA, fibronectin, and collagen I and III in response to TGF‐β1 in healthy mouse fibroblasts was suppressed following lanatoside C administration by inhibition of TGF‐β1/Smad signalling. In addition, TGF‐β1‐induced migration in lung fibroblasts was also impeded after lanatoside C treatment. Together, our data revealed that lanatoside C alleviated BLM‐induced pulmonary fibrosis in mice via attenuation of growth and differentiation of fibroblasts, suggesting that it has potential as a candidate therapy for PF patients.