Endoglin in liver fibrogenesis: Bridging basic science and clinical practice

Endoglin, also known as cluster of differentiation CD105, was originally identified 25 years ago as a novel marker of endothelial cells. Later it was shown that endoglin is also expressed in pro-fibrogenic cells including mesangial cells, cardiac and scleroderma fibroblasts, and hepatic stellate cells. It is an integral membranebound disulfide-linked 180 kDa homodimeric receptor that acts as a transforming growth factor-β(TGF-β) auxiliary co-receptor. In humans, several hundreds of mutations of the endoglin gene are known that give rise to an autosomal dominant bleeding disorder that is characterized by localized angiodysplasia and arteriovenous malformation. This disease is termed hereditary hemorrhagic telangiectasia type Ⅰ and induces various vascular lesions, mainly on the face, lips, hands and gastrointestinal mucosa. Two variants of endoglin(i.e., S- and L-endoglin) are formed by alternative splicing that distinguishes from each other in the length of their cytoplasmic tails. Moreover, a soluble form of endoglin, i.e.,sol-Eng, is shedded by the matrix metalloprotease-14 that cleaves within the extracellular juxtamembrane region. Endoglin interacts with the TGF-β signaling receptors and influences Smad-dependent and-independent effects. Recent work has demonstrated that endoglin is a crucial mediator during liver fibrogenesis that critically controls the activity of the different Smad branches. In the present review, we summarize the present knowledge of endoglin expression and function, its involvement in fibrogenic Smad signaling, current models to investigate endoglin function, and the diagnostic value of endoglin in liver disease.

Smad7 dependent expression signature highlights BMP2 and HK2 signaling in HSC transdifferentiation

AIM: To analyse the influence of Smad7, antagonist of transforming growth factor (TGF)-β canonical signaling pathways on hepatic stellate cell (HSC) transdifferentia-tion in detail. METHODS: We systematically analysed genes regulated by TGF-β/Smad7 in activated HSCs by microarray analy-sis and validated the results using real time polymerase chain reaction and Western blotting analysis. RESULTS: We identif ied 100 known and unknown tar-gets underlying the regulation of Smad7 expression and delineated 8 gene ontology groups. Hk2, involved in glycolysis, was one of the most downregulated proteins, while BMP2, activator of the Smad1/5/8 pathway, was extremely upregulated by Smad7. However, BMP2 de-pendent Smad1 activation could be inhibited in vitro by Smad7 overexpression in HSCs. CONCLUSION: We conclude (1) the existence of a tight crosstalk of TGF-β and BMP2 pathways in HSCs and (2) a Smad7 dependently decreased sugar metabolism ameliorates HSC activation probably by energy with-drawal.

TGF-β1基因多态性与肝炎后肝纤维化的相关性研究

目的:探讨TGF-β1基因多态性与肝炎后肝纤维化的关系。方法:以实时荧光PCR结合熔点曲线分析,建立可高通量检测TGF-β1编码区3个单核苷酸多态性(SNPs)位点的LightCycler方法,这3个位点分别为Leu10Pro(T>C)、Arg25Pro(G>C)、Thr263Ile(C>T),并对亚洲人群中HBV感染导致的肝纤维化患者(90例)及高加索人群中HCV感染导致的肝纤维化患者(210例)进行SNP分析,并分别与104例亚洲人群和50例高加索人群正常献血员进行比较。结果:亚洲人群中病患组与正常对照组TGF-β1编码区第25、263位氨基酸皆无基因多态性,与高加索人群的检测结果有显著差异;而亚洲人群第10位氨基酸基因多态性出现频率相对较高,病患组(T／C=0.444／0.556)较正常对照组(T／C=0.514／0.486)突变频率稍高,但无显著差异。在高加索人群HCV感染导致的肝纤维化患者中第10、25位氨基酸基因多态性出现的频率与肝纤维化发展程度(average METAVIR-Score)密切相关。结论:提示TGF-β1基因多态性与高加索人群肝炎后肝纤维化的发生具有重要相关性;与亚洲人群肝炎后肝纤维化发生的相关性有待进一步研究。

转化生长因子-β1及其基因多态性与多发性骨髓瘤的关系研究

目的:探讨转化生长因子-β1(TGF-β1)分子表达水平及其编码区基因多态性与多发性骨髓瘤(Mu ltip le myelo-m a,MM)的关系。方法:应用ELISA方法检测标本血浆TGF-β1的浓度,应用L ightCyc ler实时荧光PCR结合熔点曲线分析的方法检测转化生长因子-β1编码区3个基因多态性:codon10 T>C(Leu10Pro)、codon25 G>C(Arg25Pro)和codon263 C>T(Thr263 Ile)。结果:患者血浆TGF-β1浓度明显高于对照组,但TGF-β1基因codon10位点各种基因型和等位基因在对照组和MM患者组以及MM患者各型之间的分布频率并没有显著差异,而且MM患者各种基因型血浆TGF-β1的浓度也没有显著差异,TGF-β1基因codon25和codon263位点均不存在预想中的基因多态性。结论:转化生长因子-β1可能在多发性骨髓瘤的发生中起到一定的作用,但该因子基因编码区多态性并不会影响血浆TGF-β1的浓度,也与MM的发生以及亚型没有明确的相关性。

神经精神药理学治疗药物监测共识指南:2017版

治疗药物监测(Therapeutic Drug Monitoring,TDM)通过定量测定和解释血药浓度以优化药物治疗。TDM着眼于药代动力学的个体差异,使个体化药物治疗成为可能。在精神病学和神经病学领域中,有可能明显获益于TDM的主要患者群体包括少年儿童、孕妇、老年患者、智障患者、药物滥用者、涉法精神病患者、已知或怀疑药代动力学异常的患者以及合并躯体疾病影响药代动力学的患者。常规剂量下治疗无效,用药依从性难以判断,药物耐受性不佳,以及可能存在药代动力学方面的药物-药物相互作用等情况都是治疗药物监测的典型指征。然而,只有将TDM充分整合到临床治疗过程中,才能发挥其优化药物治疗的潜在优势。为了向临床医生和实验室提供有效的TDM信息,神经精神药理学与药物精神病学协会(Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie,AGNP)的TDM专家组在2004年发表了第一版《精神科治疗药物监测指南》。2011年进行了更新之后,现在再次更新。遵循新版指南,可能会改善神经精神药物治疗的效果,加快很多患者的康复,并降低医疗费用。

神经精神药理学治疗药物监测共识指南:2017版

2.2剂量相关参考浓度范围对于TDM结果的解释,除了治疗参考浓度范围外还有另一个浓度范围,即所谓的剂量相关参考浓度范围。治疗参考浓度范围的应用是药效动力学问题,而剂量相关参考浓度范围的运用是药代动力学问题。后者比较的是测得的药物浓度与理论预期药物浓度范围。参照药代动力学研究,优先考虑没有合并用药或药物基因组异常的患者群(“正常”患者),在日维持剂量(Daily maintenance dose,D m)、给药间隔(Dosing interval,d i)、总清除率(Total clearance,CL)和生物利用度(Bioavailability,F)已知情况下,某种药物在某个“正常”患者体内的预期平均稳态浓度(Average steady-state concentration,C av)可通过下面的公式计算。

Non-invasive biomarkers for monitoring the fibrogenic process in liver:A short survey

The clinical course ofchronic liver diseases is significantly dependent on the progression rate and the extent offibrosis, i.e. the non-structured replacement of necrotic parenchyma by extracellular matrix. Fibrogenesis, i.e. the development offibrosis can be regarded as an unlimited wound healing process, which is based on matrix (connective tissue) synthesis in activated hepatic stellate cells, fibroblasts (fibrocytes), hepatocytes and biliary epithelial cells, which are converted to matrix-producing (myo-)fibroblasts by a process defined as epithelial-mesenchymal transition. Blood (noninvasive) biomarkers offibrogenesis and fibrosis can be divided into class and class analytes. Class biomarkers are those single tests, which are based on the pathophysiology offibrosis, whereas class biomarkers aremostly multiparametric algorithms, which have been statistically evaluated with regard to the detection and activity ofongoing fibrosis. Currently available markers fulfil the criteria ofideal clinical-chemical tests only partially, but increased understanding ofthe complex pathogenesis offibrosis offers additional ways for pathophysiologically well based serum (plasma) biomarkers. They include TGF-β-driven marker proteins, bone marrow-derived cells (fibrocytes), and cytokines, which govern proand anti-fibrotic activities. Proteomic and glycomic approaches ofserum are under investigation to set up specific protein or carbohydrate profiles in patients with liver fibrosis. These and other novel parameters will supplement or eventually replaceliver biopsy/histology, high resolution imaging analysis, and elastography for the detection and monitoring of patients at risk ofdeveloping liver fibrosis.

Connective tissue growth factor reacts as an IL-6/STAT3-regulated hepatic negative acute phase protein

AIM:To investigate the mechanisms involved in a possible modulator role of interleukin(IL) -6 signalling on CYR61-CTGF-NOV(CCN) 2/connective tissue growth factor(CTGF) expression in hepatocytes(PC) and to look for a relation between serum concentrations of these two parameters in patients with acute inflammation. METHODS:Expression of CCN2/CTGF,p-STAT3,p-Smad 3/1 and p-Smad2 was examined in primary freshly isolated rat or cryo-preserved human PC exposed to various stimuli by Western blotting,electrophoretic mobility shift assay(EMSA) ,reporter-gene-assays and reversetranscriptase polymerase chain reaction. RESULTS:IL-6 strongly down-regulated CCN2/CTGF protein and mRNA expression in PC,enhanceable by extracellular presence of the soluble IL-6 receptor gp80,and supported by an inverse relation between IL-6 and CCN2/CTGF concentrations in patients'sera.The inhi-bition of TGFβ1 driven CCN2/CTGF expression by IL-6 did not involve a modulation of Smad2(and Smad1/3) signalling.However,the STAT3 SH2 domain binding peptide,a selective inhibitor of STAT3 DNA binding activity,counteracted the inhibitory effect of IL-6 on CCN2/CTGF expression much more pronounced than pyrrolidine-dithiocarbamate,an inhibitor primarily of STAT3 phosphorylation.An EMSA confirmed STAT3 binding to the proposed proximal STAT binding site in the CCN2/CTGF promoter. CONCLUSION:CCN2/CTGF is identified as a hepatocellular negative acute phase protein which is downregulated by IL-6 via the STAT3 pathway through interaction on the DNA binding level.

Human intestinal acyl-CoA synthetase 5 is sensitive to the inhibitor triacsin C

AIM:To investigate whether human acyl-CoA synthetase 5(ACSL5) is sensitive to the ACSL inhibitor triacsin C.METHODS:The ACSL isoforms ACSL1 and ACSL5 from rat as well as human ACSL5 were cloned and recombinantly expressed as 6xHis-tagged enzymes.Ni 2+-affinity purified recombinant enzymes were assayed at pH 7.5 or pH 9.5 in the presence or absence of triacsin C.In addition,ACSL5 transfected CaCo2 cells and intestinal human mucosa were monitored.ACSL5 expression in cellular systems was verified using Western blot and immunofluorescence.The ACSL assay mix included TrisHCl(pH 7.4),ATP,CoA,EDTA,DTT,MgCl 2,[9,103 H] palmitic acid,and triton X-100.The 200 μL reaction was initiated with the addition of solubilized,purified recombinant proteins or cellular lysates.Reactions were terminated after 10,30 or 60 min of incubation with Doles medium.RESULTS:Expression of soluble recombinant ACSL proteins was found after incubation with isopropyl betaD-1-thiogalactopyranoside and after ultracentrifugation these were further purified to near homogeneity with Ni 2+-affinity chromatography.Triacsin C selectively and strongly inhibited recombinant human ACSL5 protein at pH 7.5 and pH 9.5,as well as recombinant rat ACSL1(sensitive control),but not recombinant rat ACSL5(insensitive control).The IC50 for human ACSL5 was about 10 μmol/L.The inhibitory triacsin C effect was similar for different incubation times(10,30 and 60 min) and was not modified by the N-or C-terminal location of the 6xHis-tag.In order to evaluate ACSL5 sensitivity to triacsin C in a cellular environment,stable human ACSL5 CaCo2 transfectants and mechanically dissected normal human intestinal mucosa with high physiological expression of ACSL5 were analyzed.In both models,ACSL5 peak activity was found at pH 7.5 and pH 9.5,corresponding to the properties of recombinant human ACSL5 protein.In the presence of triacsin C(25 μmol/L),total ACSL activity was dramatically diminished in human ACSL5 transfectants as well as in ACSL5-rich human intestinal mucosa.CONCLUSION:The data strongly indicate that human ACSL5 is sensitive to triacsin C and does not compensate for other triacsin C-sensitive ACSL isoforms.

Harnessing naturally occurring mutations for T-cell therapy:a potential new avenue to enhance treatment efficacy

In a recent study published in Nature,Garcia et al.use a sophisticated approach to identify fitness-enhancing mutations for T cells that was inspired by cancer evolution.1 The identified CARD11-PIK3R3 gene fusion enhanced tumor rejection and persistence of engineered T cells in multiple tumor models and might have the potential to improve efficacy of adoptive T-cell therapies in cancer patients.

Cytotoxic FCER1G^(+) innate-like T cells:new potential for tumour immunotherapy

In a recent study published in Nature,Chou and colleagues define a new evolutionarily conserved class of tumour-elicited immune response mediated by a distinct population of T cell receptor(TCR)-positive FCER1G-expressing innate-like T cells with high cytotoxic potential(αβILTCKs).1 Targeted immunotherapies and most prominently immune checkpoint blockade(ICB)therapies,brought clinical benefits to tumour patients that were inconceivable 15 years ago.2 These ICBs target inhibitory receptors such as PD-1 on tumour infiltrating CD8+cytotoxic T lymphocytes(CTLs)that can recognise mutated cancer cell antigens and thereby enable tumour cell killing.Yet,a significant cohort of cancer patients are non-responsive to ICB treatment and therefore,there is a strong need to discover additional anti-cancer immunomechanisms.Recent work in Nature by Chou and colleagues identifies a population ofαβILTCKs that exhibit reactivity to unmutated tumour antigens.