Bile acid interactions with cholangiocytes

Cholangiocytes 在他们的顶端的膜暴露于胆汁酸的高集中。为胆汁酸的选择 transporter，顶端的钠胆汁酸 Cotransporter (ASBT )( 也叫作 Ibat；基因名字 Slc10a2 ) 在 cholangiocyte 上是局部性的顶端的膜。在 basolateral 膜上，四个运输系统被识别了(t-ASBT，多药抵抗(MDR ) 3，一个未辩别出的阴离子 exchanger 系统和器官的溶质 transporter (Ost ) 异侧 transporter， Ostalpha-Ostbeta。一起，这些单向性地搬运 ers 从管的胆汁的行动胆汁酸到发行量。cholangiocytes 吸收的胆汁酸为重新分泌物经由仙子胆管丛再循环回到 hepatocytes 进胆汁。这再循环在 hepatocytes 和 cholangiocytes 之间的胆汁酸被叫作 cholehepatic 分流小径。最近的研究建议 cholehepatic 分流小径可以由于额外的肝的阻塞在胆汁酸并且到改编的全面肝胆管运输作出贡献到长期的胆汁郁积。ASBT 被腺苷 3' 尖锐地调整， 5'-monophosphate (营地) 依赖者易位到顶端的膜并且由 phosphorylation 依赖的 ubiquitination 和 proteasome 降级。ASBT 被变化长期地响应胆汁的胆汁酸集中和煽动性的 cytokines 在基因表示调整。cholangiocyte ASBT 的另一潜在的功能是允许 cholangiocytes 取样胆汁的胆汁酸以便激活细胞内部的表明小径。在细胞内部的钙，蛋白质激酶 C (PKC ) ， phosphoinositide 3-kinase (PI3K ) ，激活 mitogen 的蛋白质(地图) 激酶和细胞外的调整信号的蛋白质激酶(英皇家空军之阶级最低之兵) 的胆汁酸扳机变化细胞内部的信号。胆汁酸显著地改变 cholangiocyte 分泌物，增长和幸存。不同胆汁酸在 cholangiocyte 上有微分效果细胞内部发信号，并且在一些例子，扳机反对在 cholangiocyte 上完成分泌物，增长和幸存。在这些之上基于概念和观察， cholangiocyte 被建议了是为在肝的胆汁酸的原则目标房间。

Cholangiocytes and blood supply

胆汁的树的微脉管的供应，仙子胆管丛(PBP ) ，源自肝的动脉树枝和流动进肝窦状隙。PBP 的详细三维的研究被使用扫描电子执行了显微镜学脉管的腐蚀演员组(SEMvcc ) 技术。认为 PBP 在支持胆汁的上皮的能分泌、吸收性的功能起一个基本作用，他们在常态和病理的组织被探索。正常的肝证明 PBP 安排在 extra-附近 -- 并且肝内的胆汁的树。在小门道， PBP 被日益增多地继续了它显示出一个更复杂的脉管的网络的额外的肝的 PBP 的 capillaries 的单个层描绘。在普通的管结扎(BDL ) 以后，胆汁管和 PBP 增长的进步修正被观察。PBP 介绍在许多胆汁管附近安排的一个三维的网络并且作为容器的捆出现，由有典型圆网孔结构的同类的直径的 capillaries 镇静。PBP 网络从显得正常的正弦曲线网络是容易可区分的。在 BDL 期间考虑 PBP 的庞大的延期，脉管的内皮生长因素(VEGF ) 起的可能的作用被评估。VEGF -- A， VEGF-C 和他们的相关受体高度出现了在 BDL 老鼠的增殖的 cholangiocytes 积极的免疫。到象肝的动脉结扎一样的 BDL 老鼠的 anti-VEGF-A 或 anti-VEGF-C 抗体的管理导致了一个减少的胆汁管团。rVEGF 的管理 -- 到 BDL 肝的动脉的 A 绑扎老鼠阻止了 cholangiocyte 增长和 VEGF 的减少 -- 表情作为与 BDL 控制老鼠相比。这些数据处于 cholangiocyte 增长的条件建议胆汁的树的动脉的血供给的角色，例如它发生在长期的胆汁郁积期间。在另一方面， VEGF 作为在 cholangiocytes 和 PBP endothelial 之间的串音的一个工具起的作用建议 VEGF 版本和功能的那操作能为肝的动脉或胆汁的树的损坏描绘的人的病理学的条件代表治疗学的策略。

Heterogeneity of the intrahepatic biliary epithelium

这评论的目的是在 apoptotic，增生的和分泌活动与变化构画出与胆汁的上皮的词法异质和对肝胃肠激素和肽和肝损伤的不同大小的胆汁管的异构的 pathophysiological 回答有关的最近的调查结果。因为胆汁的上皮细胞(cholangiocytes ) 是人的 cholangiopathies 的目标的识别，胆汁的功能的知识很快正在增加，它被胆汁管的增长 / 损坏在尺寸的一个小范围以内描绘。胆汁的上皮的唯一的解剖，形态学，神经分布和血管形成与在胆汁的树的不同区域以内的 cholangiocytes 的功能一致。在活体内模型[例如，胆汁管结扎( BDL )，部分肝切除术，胆汁酸，四氯化碳( CCl4 )或 alpha-naphthylisothiocyanate ( ANIT )喂]并且在活体内试验性的工具[例如，刚孤立小、大的 cholangiocytes 或肝内胆汁管单位( IBDU )和小、大的鼠科的 cholangiocytes 的主要文化]允许我们表明肝内的胆汁的上皮的词法、功能的异质。这些模型表明了微分分泌活动和异构的 apoptotic 和不同的大小的管的增生的回答。类似于限制为特定的大小的管的 cholangiocyte 增长 / 损害的动物模型，在人的肝疾病，胆汁管损坏支配特定的大小的胆汁管。与肝内的胆汁的上皮的功能的异质有关的未来研究可以与 cholangiopathies 为病人揭示新 pathophysiological 治疗。

Role of sex hormones in the modulation of cholangiocyte function

Over the last years,cholangiocytes,the cells that line the biliary tree,have been considered an important object of study for their biological properties which involves bile formation,proliferation,injury repair,fibrosis and angiogenesis.Cholangiocyte proliferation occurs in all pathologic conditions of liver injury where it is associated with inflammation and regeneration.During these processes,biliary cells start to secrete different cytokines,growth factors,neuropeptides and hormones which represent potential mechanisms for cross talk with other liver cells.Several studies suggest that hormones,and in particular,sex hormones,play a fundamental role in the modulation of the growth of this compartment in the injured liver which functionally conditions the progression of liver disease.Understanding the mechanisms of action and the intracellular pathways of these compounds on cholangiocyte pathophysiology will provide new potential strategies for the management of chronic liver diseases.The purpose of this review is to summarize the recent findings on the role of sex hormones in cholangiocyte proliferation and biology.

Role of the melatonin/menin signaling in the regulation of cholangiocarcinoma growth

Objective:There is decreased expression of arylalkylamine N-acetyltransferase(the rate-limiting enzyme regulating melatonin synthesis)and the clock gene,Per1 and increased expression of the MT1 melatonin receptor subtype in cholangiocarcinoma(CCA).This study tested the hypothesis that the inhibitory effects of the melatonin/MT1/Per1 axis on CCA growth are mediated by inhibition of miR-24.

Emerging Therapeutic Strategies in The Fight Against Primary Biliary Cholangitis

The liver has a vital role in many metabolic and regulatory processes in the body.Primary biliary cholangitis(PBC),previously known as primary biliary cirrhosis,is a chronic cholestatic autoimmune disease of the intrahepatic bile ducts associated with loss of tolerance to mitochondrial antigens.At this time there is no definitive cure for PBC;however,ursodeoxycholic acid(UDCA)has been shown to reduce injury when administered as the first line of treatment.Additional therapeutics can be given concurrently or as an alternative to UDCA to manage the symptoms and further curb disease progression.Currently,a liver transplant is the only potentially curative option when the patient has developed end-stage liver disease or intractable pruritus.This review aims to delineate the pathogenesis of primary biliary cholangitis and shed light on current therapeutic strategies in the treatment of PBC.

Functional roles of gut bacteria imbalance in cholangiopathies

Cholangiopathies are caused by bile duct damage or inflammation followed by cholestasis leading to liver fibrosis.Bile duct epithelial cells,cholangiocytes,are a primary target for cholangiopathies.Ductular reaction is often observed in cholangiopathies and the proliferation of cholangiocytes is associated with ductular reaction and liver fibrogenesis.Accumulating evidence suggests that patients with chol-angiopathies have different gut bacterial profiles from healthy individuals,indicating the association between gut microbiota and cholangiopathies.Bile acids are produced by hepatocytes and modified by gut bacteria.Bile acids regulate cholangiocyte proliferation but effects vary depending on the type of bile acids.Recent studies suggest that therapies targeting gut bacteria,such as antibiotics administration and gut bacteria depletion or therapies using gut bacteria-associated bile acids,such as ursodeoxycholic acid(UDCA)administration,may be useful for treatments of cholangiopathies,although data are contro-versial depending on animal models or cohorts.This review summarizes current understandings of functional roles of gut bacterial imbalance and strategies for treatments of cholangiopathies targeting gut bacteria.

Adoptive transfer of Pfkfb3-disrupted hematopoietic cells to wild-type mice exacerbates diet-induced hepatic steatosis and inflammation

Background and objectives:Hepatic steatosis and inflammation are key characteristics of non-alcoholic fatty liver disease(NAFLD).However,whether and how hepatic steatosis and liver inflammation are differentially regulated remains to be elucidated.Considering that disruption of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3(Pfkfb3/iPfk2)dissociates fat deposition and inflammation,the present study examined a role for Pfkfb3/iPfk2 in hematopoietic cells in regulating hepatic steatosis and inflammation in mice.Methods:Pfkfb3-disrupted(Pfkfb3^(+/-))mice and wild-type(WT)littermates were fed a high-fat diet(HFD)and examined for NAFLD phenotype.Also,bone marrow cells isolated from Pfkfb3^(+/-)mice andWT mice were differentiated into macrophages for analysis of macrophage activation status and for bone marrow transplantation(BMT)to generate chimeric(WT/BMT-Pfkfb3^(+/-))mice in which Pfkfb3 was disrupted only in hematopoietic cells and control chimeric(WT/BMT-WT)mice.The latter were also fed an HFD and examined for NAFLD phenotype.In vitro,hepatocytes were co-cultured with bone marrowderived macrophages and examined for hepatocyte fat deposition and proinflammatory responses.Results:After the feeding period,HFD-fed Pfkfb3^(+/-)mice displayed increased severity of liver inflammation in the absence of hepatic steatosis compared with HFD-fed WT mice.When inflammatory activation was analyzed,Pfkfb3^(+/-)macrophages revealed increased proinflammatory activation and decreased anti-proinflammatory activation.When NAFLD phenotype was analyzed in the chimeric mice,WT/BMT-Pfkfb3^(+/-) mice displayed increases in the severity of HFD-induced hepatic steatosis and inflammation compared with WT/BMT-WT mice.At the cellular level,hepatocytes co-cultured with Pfkfb3^(+/-) macrophages revealed increased fat deposition and proinflammatory responses compared with hepatocytes co-cultured with WT macrophages.Conclusions:Pfkfb3 disruption only in hematopoietic cells exacerbates HFD-induced hepatic steatosis and inflammation whereas the Pfkfb3/iPfk2 in nonhematopoietic cells appeared to be needed for HFD feeding to induce hepatic steatosis.As such,the Pfkfb3/iPfk2 plays a unique role in regulating NAFLD pathophysiology.

Diagnostic and therapeutic potentials of microRNAs in cholangiopathies

Cholangiopathies are a group of rare,devastating diseases that arise from damaged cholangiocytes,the cells that line the intra-and extra-hepatic bile ducts of the biliary epithelium.Cholangiopathies result in significant morbidity and mortality and are a major cause of liver transplantation.A better understanding of the underlying pathogenesis that influences cholangiocyte dysregulation and cholangiopathy progression is necessary,considering the dismal prognosis associated with these diseases.MicroRNAs are a class of small,non-coding RNAs that regulate post-transcriptional mRNA expression of specific genes.The role of microRNAs has expanded to include the initiation and development of many diseases,including cholangiopathies.Understanding microRNA regulation of cholangiopathies may provide diagnostic and therapeutic benefit for these diseases.In this review,the authors primarily focus on studies published within the last five years that help determine the diagnostic and therapeutic potential of microRNAs in cholangiopathies.