Glaser Shannon S, Ueno Yoshiyuki, DeMorrow Sharon, Chiasson Valorie L, Katki Khurshed A, Venter Julie, Francis Heather L, Dickerson Ian M, DiPette Donald J, Supowit Scott C, Alpini Gianfranco D
Department of Medicine, Scott & White Hospital, The Texas A&M University System Health Science Center, College of Medicine, Temple, TX 76504, USA.
Lab Invest. 2007 Sep;87(9):914-26. doi: 10.1038/labinvest.3700602. Epub 2007 Jul 9.
The role of sensory innervation in the regulation of liver physiology and the pathogenesis of cholestatic liver disease are undefined. Biliary proliferation has been shown to be coordinately controlled by parasympathetic and sympathetic innervation of the liver. The aim of our study was to address the role of the sensory neuropeptide calcitonin gene-related peptide (alpha-CGRP) in the regulation of cholangiocyte proliferation during cholestasis induced by extrahepatic bile duct obstruction (BDL). Our study utilized a knockout (KO) mouse model, which lacks the sensory neuropeptide alpha-CGRP. Wild-type (WT) and alpha-CGRP KO mice were subjected to sham surgery or BDL for 3 and 7 days. In addition, immediately after BDL, WT and KO mice were administered the CGRP receptor antagonist (CGRP(8-37)) for 3 and 7 days by osmotic minipumps. Liver sections and isolated cholangiocytes were evaluated for proliferation markers. Isolated WT BDL (3 days) cholangiocytes were stimulated with alpha- and beta-CGRP and evaluated for proliferation and cAMP-mediated signaling. Lack of alpha-CGRP inhibits cholangiocyte proliferation induced by BDL at both 3 and 7 days. BDL-induced cholangiocyte proliferation in WT mice was associated with increases of circulating alpha-CGRP levels. In vitro, alpha- and beta-CGRP stimulated proliferation in purified BDL cholangiocytes, induced elevation of cAMP levels, and stimulated the activation of cAMP-dependent protein kinase A and cAMP response element binding protein DNA binding. In conclusion, sensory innervation of the liver and biliary expression of alpha-CGRP play an important role in the regulation of cholangiocyte proliferation during cholestasis.
感觉神经支配在肝脏生理调节和胆汁淤积性肝病发病机制中的作用尚不清楚。研究表明，肝脏的副交感神经和交感神经支配可协调控制胆管增殖。我们研究的目的是探讨感觉神经肽降钙素基因相关肽（α-CGRP）在肝外胆管梗阻（BDL）诱导的胆汁淤积期间胆管细胞增殖调节中的作用。我们的研究使用了一种缺乏感觉神经肽α-CGRP的基因敲除（KO）小鼠模型。野生型（WT）和α-CGRP KO小鼠接受假手术或BDL处理3天和7天。此外，在BDL后立即通过渗透微型泵给WT和KO小鼠注射CGRP受体拮抗剂（CGRP(8-37)），持续3天和7天。对肝脏切片和分离的胆管细胞进行增殖标志物评估。用α-CGRP和β-CGRP刺激分离的WT BDL（3天）胆管细胞，并评估其增殖和cAMP介导的信号传导。缺乏α-CGRP在第3天和第7天均抑制BDL诱导的胆管细胞增殖。WT小鼠中BDL诱导的胆管细胞增殖与循环α-CGRP水平升高有关。在体外，α-CGRP和β-CGRP刺激纯化的BDL胆管细胞增殖，诱导cAMP水平升高，并刺激cAMP依赖性蛋白激酶A和cAMP反应元件结合蛋白DNA结合的激活。总之，肝脏的感觉神经支配和α-CGRP的胆管表达在胆汁淤积期间胆管细胞增殖的调节中起重要作用。
