Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0239946 (liver fibrosis)
8,268 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eosinophils are frequently found in increased numbers in a variety of chronic fibrotic diseases; however, their role in the development of hepatic fibrosis has not been dissected in vivo. Here, we used interleukin-5 (IL-5) knockout (KO) mice to determine whether eosinophils contribute to the progressive liver fibrosis that develops in response to chronic Schistosoma mansoni infection. Although infection intensities were similar in C57BL/6 and IL-5 KO mice, the average size of granulomas was significantly smaller in both acutely and chronically infected IL-5 KO mice. Their granulomas were also completely devoid of eosinophils. In addition, the knockout mice displayed over a 40% reduction in hepatic fibrosis by week 16 postinfection. The reduced fibrosis was associated with increased production of the antifibrotic cytokine gamma interferon. Moreover, although IL-13 production did not decrease consistently in the absence of IL-5, IL-13-triggered responses were substantially reduced in the granulomatous tissues. This was confirmed by analyzing the expression of several genes associated with alternative macrophage activation, including arginase 1, Fizz-1, and YM-1. Importantly, all of these IL-13-regulated genes have been linked with the mechanisms of wound healing and fibrosis. In addition to IL-5 polarizing the antigen-specific CD4+ Th2 cell response, we found that granuloma eosinophils were themselves a significant source of IL-13. Thus, by producing profibrotic mediators and polarizing the Th2 response, these findings illustrate both direct and indirect roles for eosinophils and IL-5 in the pathogenesis of schistosomiasis-induced liver fibrosis. Thus, inhibiting the activity of IL-5 or eosinophils may prove effective for a variety of chronic fibrotic diseases.
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PMID:Interleukin-5 (IL-5) augments the progression of liver fibrosis by regulating IL-13 activity. 1649 17

The IL-21 receptor (IL-21R) shows significant homology with the IL-4R, and CD4+ Th2 cells are an important source of IL-21. Here we examined whether the IL-21R regulates the development of Th2 responses in vivo. To do this, we infected IL-21R-/- mice with the Th2-inducing pathogens Schistosoma mansoni and Nippostrongylus brasiliensis and examined the influence of IL-21R deficiency on the development of Th2-dependent pathology. We showed that granulomatous inflammation and liver fibrosis were significantly reduced in S. mansoni-infected IL-21R-/- mice and in IL-21R+/+ mice treated with soluble IL-21R-Fc (sIL-21R-Fc). The impaired granulomatous response was also associated with a marked reduction in Th2 cytokine expression and function, as evidenced by the attenuated IL-4, IL-13, AMCase, Ym1, and FIZZ1 (also referred to as RELMalpha) responses in the tissues. A similarly impaired Th2 response was observed following N. brasiliensis infection. In vitro, IL-21 significantly augmented IL-4Ralpha and IL-13Ralpha1 expression in macrophages, resulting in increased FIZZ1 mRNA and arginase-1 activity following stimulation with IL-4 and IL-13. As such, these data identify the IL-21R as an important amplifier of alternative macrophage activation. Collectively, these results illustrate an essential function for the IL-21R in the development of pathogen-induced Th2 responses, which may have relevance in therapies for both inflammatory and chronic fibrotic diseases.
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PMID:The IL-21 receptor augments Th2 effector function and alternative macrophage activation. 1677 88

The disease manifestations of schistosomiasis arise from the mammalian host-mediated type 2 T-helper cell-induced (Th2) fibro-granulomatous inflammatory response to eggs trapped within host tissues. Activated hepatic stellate cells are well described as the effector cells of hepatic fibrosis in a variety of human diseases and rodent models. The aim of this study was to further understand the mechanism of fibrosis and the role of hepatic stellate cells in hepatic schistosomiasis progression. Groups of female CBA mice, which produce an intermediate degree of Schistosoma japonicum-induced liver fibrosis, were infected with S. japonicum, perfused at fortnightly time points and the liver tissue and contained egg granulomas examined by immunohistochemistry and cytokine and chemokine analysis using quantitative PCR. Immunohistochemistry demonstrated the presence of activated hepatic stellate cells in the periphery of egg granulomas, adjacent to fibrotic areas. Time course analysis demonstrated that the transcription of smooth muscle actin-alpha type 1 collagen, IL-4, IL-13, IL-13Ralpha2 and tissue inhibitor of metalloproteinase-1 mirrored the initial increase and subsequent down-modulation of granuloma diameter in mice. However, the transcription of monocyte chemo-attractant protein-1, Regulated upon Activation Normal T Cell Expressed and Secreted (RANTES), TNF-alpha, IFN-gamma and matrix metalloproteinase-9 paralleled the evolution of the total liver disease burden. Transforming growth factor-beta1 transcription did not appear to be of biological significance in this mouse model. Immunohistochemical analysis of human hepatic granulomas showed close association of smooth muscle actin-alpha-expressing cells with fibrosis in five available cases of end-stage (advanced) schistosomiasis japonica. We conclude that activated hepatic stellate cells play a contributory role in the granulomatous, fibrotic process induced by S. japonicum eggs, both in the murine model and in human disease.
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PMID:A contributory role for activated hepatic stellate cells in the dynamics of Schistosoma japonicum egg-induced fibrosis. 1680 22

Adenosine is a potent endogenous regulator of tissue repair that is released from injured cells and tissues. Hepatic fibrosis results from chronic hepatic injury, and we have previously reported that endogenously generated adenosine, acting at A(2A) receptors, plays a role in toxin-induced hepatic fibrosis. Adenosine may form intracellularly and then be transported to the extracellular space or it may form extracellularly from adenine nucleotides released from injured cells. Because ecto-5'-nucleotidase (CD73) catalyzes the terminal step in extracellular adenosine formation from AMP, we determined whether CD73 plays a role in the development of hepatic fibrosis. Mice were treated overnight with PBS, CCl(4), ethanol, or thioacetamide (TAA); their livers were harvested, and slices were incubated in medium for 20 h before adenosine concentration in the supernatant was measured by HPLC. Hepatic fibrosis was induced by CCl(4) or TAA treatment in CD73 knockout (CD73KO and C57BL/6 background) and C57BL/6 control mice [wild-type (WT)] mice and quantified by digital analysis of picrosirius red stained slides and hydroxyproline content. mRNA expression was quantified by real-time polymerase chain reaction, and protein was quantified by Western blot or enzyme-linked immunosorbent assay. Livers from WT mice treated with CCl(4), ethanol, and TAA released 2- to 3-fold higher levels of adenosine than livers from comparably treated CD73KO mice. CD73KO mice were protected from fibrosis with significantly less collagen content in the livers of CD73KO than WT mice after treatment with either CCl(4) or TAA. There were far fewer alpha-smooth muscle actin positive hepatic stellate cells in CCl(4)-treated KO mice than that in WT mice. After CCl(4) treatment, the mRNA level of A(1), A(2A), A(2B), and A(3) adenosine receptors, tumor necrosis factor-alpha, interleukin (IL) -1beta, IL-13r alpha1, matrix metalloproteinase (MMP)-2, MMP-14, tissue inhibitor of metalloproteinase (TIMP) -1, and TIMP-2, and IL-13 level increased markedly in both CD73KO and WT mice, but Col1 alpha1, Col3 alpha1, and transforming growth factor-beta1 mRNA increased much more in WT mice than that in KO mice. Moreover, IL-13r alpha2, MMP-13 mRNA, and MMP-13 protein were higher in KO mice than that in WT mice. These results indicate that adenosine, formed extracellularly from adenine nucleotides, plays a major role in the pathogenesis of hepatic fibrosis and that inhibition of adenosine production or blockade of adenosine receptors may help prevent hepatic fibrosis.
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PMID:Ecto-5'-nucleotidase (CD73) -mediated extracellular adenosine production plays a critical role in hepatic fibrosis. 1826 96

1. Currently, there is no satisfactory treatment for pulmonary fibrosis. Emodin, a component in Chinese herbs, has been shown to have an antifibrotic effect on pancreatic fibrosis and liver fibrosis. In the present study, we tested the hypothesis that emodin may attenuate the development of pulmonary fibrosis. 2. Mice were randomly divided into five groups (n = 16 in each). One group was a control group; the remaining four groups were treated with intratracheal instillation of 3 mg/kg bleomycin (BLM). The following day, emodin (5, 10 or 20 mg/kg per day, p.o.) treatment was started for three of the BLM-treated groups and was continued for 21 days. The fourth BLM-treated group (and the control group) received daily 0.5% sodium carboxymethyl cellulose (placebo) by gavage over the same period. 3. Bleomycin challenge provoked severe pulmonary fibrosis, with marked increases in fibrosis fraction, hydroxyproline content and myeloperoxidase activity in lung tissue. Emodin treatment (10 and 20 mg/kg per day, p.o.) attenuated all these biochemical indices, as well as histopathological alterations induced by BLM. Furthermore, in mice injected with BLM, elevated levels of transforming growth factor-beta1, interleukin (IL)-4 and IL-13 were found in bronchoalveolar lavage fluid. These increases were significantly inhibited by 10 and 20 mg/kg per day emodin. 4. In cell culture, exposure of cells to 6.25, 12.5, 25 or 50 micromol/L emodin for 24 h decreased fibroblast proliferation. Treatment of cells with the same concentrations of emodin for 72 h decreased collagen production by fibroblasts. In addition, emodin (6.25, 12.5, 25 or 50 micromol/L) inhibited the steady state expression of alpha1 (I) procollagen and alpha2 (I) procollagen mRNA in a dose-dependent manner. 5. The results of the present study suggest that emodin may be effective in the treatment of pulmonary fibrosis.
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PMID:Inhibitory effect of emodin on bleomycin-induced pulmonary fibrosis in mice. 1878 80

Nonalcoholic steatohepatitis (NASH), the most common cause of chronic liver fibrosis, progresses to cirrhosis in up to 20% of patients. We report that hepatic stellate cells (HSC) in sinusoidal lesions of liver of patients with NASH express high levels of high-affinity IL-13R (IL-13Ralpha2), which is colocalized with smooth muscle actin, whereas fatty liver and normal liver specimens do not express IL-13Ralpha2. HSCs engineered to overexpress IL-13Ralpha2 respond to IL-13 and induce TGFB1 promoter activity and TGF-beta1 production. We also developed NASH in rats by feeding a choline-deficient l-amino acid diet. These rats developed liver fibrosis as assessed by H&E staining, Masson's trichrome and Sirius red staining, and hydroxyproline assays. Treatment of these rats with IL-13R-directed cytotoxin caused a substantial decline in fibrosis and liver enzymes without organ toxicity. These studies demonstrate that functional IL-13Ralpha2 are overexpressed in activated HSCs involved in NASH and that IL-13 cytotoxin ameliorates pathological features of NASH in rat liver, indicating a novel role of this cytotoxin in potential therapy.
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PMID:Novel role of IL-13 in fibrosis induced by nonalcoholic steatohepatitis and its amelioration by IL-13R-directed cytotoxin in a rat model. 1880 68

Thymic stromal lymphopoietin was recently identified as a master switch for the development of allergen-driven Th2 responses. However, the role of thymic stromal lymphopoietin (TSLP) in the development of helminth-induced Th2 responses is unclear. Here, using TSLPR(-/-) mice, we show that while TSLPR signaling participates in the development of Schistosoma mansoni egg-induced CD4(+) Th2 responses, it plays only a transient role in the development of Th2-dependent pathology in the lung, liver, and intestine. Studies conducted in a pulmonary granuloma model showed that while a reduction in IL-4/IL-13-dependent granulomatous inflammation and tissue eosinophilia was observed in TSLPR(-/-) mice undergoing a primary response, lesion formation was not affected during a secondary granulomatous response, even though IL-5 and IL-13 were modestly reduced in the knockout mice. To evaluate the importance of TSLPR signaling in the development of a chronic Th2-dependent response, TSLPR(-/-) mice were also infected with S. mansoni cercariae. Here, the only significant difference noted in TSLPR(-/-) mice was a modest decrease in liver fibrosis in acutely infected animals. The transient decrease in fibrosis was associated with increased production of the antifibrotic cytokine IFN-gamma and decreased production of the profibrotic cytokine IL-13. Although the altered cytokine response persisted in chronically infected TSLPR(-/-) mice, it failed to reduce granuloma formation or fibrosis, confirming that TSLPR signaling plays a limited role in the development of chronic Th2-dependent pathology. Collectively, these findings suggest that while TSLPR signaling serves a key role in allergen-driven Th2 responses, it exerts minor regulatory activity during this chronic helminth infection.
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PMID:Regulation of helminth-induced Th2 responses by thymic stromal lymphopoietin. 1941 99

Lymphocyte accumulation is characteristic of chronic hepatitis, but the mechanisms regulating lymphocyte numbers and their roles in liver disease progression are poorly understood. The Hedgehog (Hh) pathway regulates thymic development and lymphopoeisis during embryogenesis, and is activated in fibrosing liver disease in adults. Our objective was to determine if Hh ligands regulate the viability and phenotype of NKT cells, which comprise a substantial sub-population of resident lymphocytes in healthy adult livers and often accumulate during liver fibrosis. The results demonstrate that a mouse invariant NKT cell line (DN32 iNKT cells), mouse primary liver iNKT cells, and human peripheral blood iNKT cells are all responsive to sonic hedgehog (Shh). In cultured iNKT cells, Shh enhances proliferation, inhibits apoptosis, induces activation, and stimulates expression of the pro-fibrogenic cytokine, IL-13. Livers of transgenic mice with an overly active Hh pathway harbor increased numbers of iNKT cells. iNKT cells also express Shh. These results demonstrate that iNKT cells produce and respond to Hh ligands, and that Hh pathway activation regulates the size and cytokine production of liver iNKT cell populations. Therefore, Hh pathway activation may contribute to the local expansion of pro-fibrogenic iNKT cell populations during certain types of fibrosing liver damage.
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PMID:Role for hedgehog pathway in regulating growth and function of invariant NKT cells. 1954 7

Liver fibrosis is characterized by an abnormal hepatic accumulation of extracellular matrix (ECM) that results from both increased deposition and reduced degradation of collagen fibres. Some studies show that transforming growth factor beta1 (TGF-beta1), alternatively activated macrophage (aaM) and interleukin 13 (IL-13) play a key role in the evolution of fibrosis, of which TGF-beta1 and IL-13 become research hotspots. TGF-beta1 mainly activates hepatic stellate cells (HSC) through TGF-beta1/Smad signal pathway, while IL-13 seems to play a rather crucial role through JAK-STAT6 signal pathway. aaM is an important source of TGF-beta1 and activated with IL-13. This paper reviews the role of those signaling molecules in cellular signal transduction of hepatic fibrosis of schistosomiasis japonica, and provides some targets for future drug development.
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PMID:[The role of TGFbeta1 and IL-13 in cellular signal transduction of hepatic fibrosis of schistosomiasis]. 2006 97

Infection with the parasitic helminth Schistosoma mansoni causes significant liver fibrosis and extracellular matrix (ECM) remodeling. Matrix metalloproteinases (MMP) are important regulators of the ECM by regulating cellular inflammation, extracellular matrix deposition, and tissue reorganization. MMP12 is a macrophage-secreted elastase that is highly induced in the liver and lung in response to S. mansoni eggs, confirmed by both DNA microarray and real-time PCR analysis. However, the function of MMP12 in chronic helminth-induced inflammation and fibrosis is unclear. In this study, we reveal that MMP12 acts as a potent inducer of inflammation and fibrosis after infection with the helminth parasite S. mansoni. Surprisingly, the reduction in liver and lung fibrosis in MMP12-deficient mice was not associated with significant changes in cytokine, chemokine, TGF-beta1, or tissue inhibitors of matrix metalloproteinase expression. Instead, we observed marked increases in MMP2 and MMP13 expression, suggesting that Mmp12 was promoting fibrosis by limiting the expression of specific ECM-degrading MMPs. Interestingly, like MMP12, MMP13 expression was highly dependent on IL-13 and type II-IL-4 receptor signaling. However, in contrast to MMP12, expression of MMP13 was significantly suppressed by the endogenous IL-13 decoy receptor, IL-13Ralpha2. In the absence of MMP12, expression of IL-13Ralpha2 was significantly reduced, providing a possible explanation for the increased IL-13-driven MMP13 activity and reduced fibrosis. As such, these data suggest important counter-regulatory roles between MMP12 and ECM-degrading enzymes like MMP2, MMP9, and MMP13 in Th2 cytokine-driven fibrosis.
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PMID:Matrix metalloproteinase 12-deficiency augments extracellular matrix degrading metalloproteinases and attenuates IL-13-dependent fibrosis. 2018 83


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