Both Ca2+-dependent and -independent pathways are involved in rat hepatic stellate cell contraction and intrahepatic hyperresponsiveness to methoxamine
Both Ca2+-dependent and -independent pathways are involved in rat hepatic stellate cell contraction and intrahepatic hyperresponsiveness to methoxamine
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DOI：
10.1152/ajpgi.00196.2006
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发表时间：
2007-02-01
影响因子：
4.5
通讯作者：
Nevens, Frederik
中科院分区：
文献类型：
--
作者：
Laleman, Wim;Van Landeghem, Lien;Nevens, Frederik
在慢性肝损伤中，肝星状细胞（HSC）被认为是窦状血管张力的调节者。我们研究了大鼠HSC中钙依赖性和钙非依赖性收缩途径的相对作用，并将这些发现与原位灌注的大鼠肝脏相关。通过应力松弛胶原晶格模型研究原代大鼠HSC的收缩。剂量-反应曲线的钙离子载体A-23187和钙调蛋白/肌球蛋白轻链激酶抑制剂W-7用于研究钙离子依赖性途径。Y-27632，staurosporin，calyculin（抑制剂Rho激酶，蛋白激酶C，肌球蛋白轻链磷酸酶，分别）被用来研究钙离子非依赖性途径。肌动球蛋白的相互作用，共同的最终目标，被抑制2，3-丁二酮单肟。此外，W-7，Y-27632，和星形孢菌素对肝内血管阻力的影响进行了评估，通过原位灌注正常和硫代乙酰胺治疗的肝硬化大鼠肝脏甲氧胺刺激（n = 25）。在体外，HSC的收缩被证明是肌动球蛋白的基础上与调节作用的Ca 2+依赖性和非依赖性途径。虽然前者似乎很重要，但后者的重要辅助作用通过它们参与“Ca 2+敏化”现象来说明。“在体内，与W-7（10（-4）M）相比，Y-27632（10（-4）M）和星形孢菌素（25 nM）预孵育的肝脏对甲氧胺（10（-4）M）的高反应性分别显著降低了-66.8 +/-1.3%，-52.4 +/-2.7%和-28.7 +/-2.8%，而在正常肝脏中，这显著更少：分别为-43.1 +/-4.2%、-40.2 +/-4.2%和-3.8 +/-6.3%。两者合计，这些结果表明，HSC的收缩是基于两个Ca 2+依赖性和非依赖性的途径，这被证明是上调的灌注肝硬化，以Ca 2+的非依赖性途径的优势。
In chronic liver injury, hepatic stellate cells (HSCs) have been implicated as regulators of sinusoidal vascular tone. We studied the relative role of Ca2+-dependent and Ca2+-independent contraction pathways in rat HSCs and correlated these findings to in situ perfused cirrhotic rat livers. Contraction of primary rat HSCs was studied by a stress-relaxed collagen lattice model. Dose-response curves to the Ca2+ ionophore A-23187 and to the calmodulin/myosin light chain kinase inhibitor W-7 served to study Ca2+-dependent pathways. Y-27632, staurosporin, and calyculin (inhibitors of Rho kinase, protein kinase C, and myosin light chain phosphatase, respectively) were used to investigate Ca2+-independent pathways. The actomyosin interaction, the common end target, was inhibited by 2,3-butanedione monoxime. Additionally, the effects of W-7, Y-27632, and staurosporin on intrahepatic vascular resistance were evaluated by in situ perfusion of normal and thioacetamide-treated cirrhotic rat livers stimulated with methoxamine (n = 25 each). In vitro, HSC contraction was shown to be actomyosin based with a regulating role for both Ca2+-dependent and -independent pathways. Although the former seem important, an important auxiliary role for the latter was illustrated through their involvement in the phenomenon of "Ca2+ sensitization." In vivo, preincubation of cirrhotic livers with Y-27632 (10(-4) M) and staurosporin (25 nM), more than with W-7 (10(-4) M), significantly reduced the hyperresponsiveness to methoxamine (10(-4) M) by -66.8 +/- 1.3%, -52.4 +/- 2.7%, and -28.7 +/- 2.8%, respectively, whereas in normal livers this was significantly less: -43.1 +/- 4.2%, -40.2 +/- 4.2%, and -3.8 +/- 6.3%, respectively. Taken together, these results suggest that HSC contraction is based on both Ca2+-dependent and -independent pathways, which were shown to be upregulated in the perfused cirrhotic liver, with a predominance of Ca2+-independent pathways.