Cytokine modulation of muscarinic receptors in the murine intestine
Cytokine modulation of muscarinic receptors in the murine intestine
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DOI：
10.1152/ajpgi.00545.2006
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发表时间：
2007-07-01
影响因子：
4.5
通讯作者：
Collins, Stephen M.
中科院分区：
文献类型：
--
作者：
Akiho, Hirotada;Khan, Waliul I.;Collins, Stephen M.
肠道运动和平滑肌收缩被肠道炎症改变的程度取决于潜在免疫激活的性质。平滑肌上的毒蕈碱受体在介导乙酰胆碱驱动的运动功能中起关键作用。我们研究了细胞因子影响肠纵肌毒蕈碱受体特征的能力，并将这些发现与碳胆碱诱导的收缩研究联系起来。从纵肌肌丛（LMMP）中分离细胞。通过[N-甲基-H-3]东莨菪碱（[H-3] NMS）结合的激动剂位移检测细胞因子受体表达、肌肉收缩性和毒蕈碱激动剂受体特性。在平滑肌细胞上鉴定到tgf - β 1受体（543 bp）和ifn - γ受体1 （660 bp）。Scatchard分析显示，在对照细胞中，[H-3] NMS的解离常数和最大结合值分别为2.6 nM和2.4 × 10(4)个位点/细胞。受线虫感染后，高亲和位点（K-H）的抑制常数降低，这与信号转导和转录激活因子无关。tgf - β 1预孵育增强了纵向肌肉收缩力，将K-H降低至2.2 μ M（增加了毒蕈碱受体亲和力），而ifn - γ预孵育使K-H增加至0.4 μ M（降低了毒蕈碱受体亲和力），并降低了纵向肌肉收缩力。IL- 13预孵育使K-H降低至0.2 nM。细胞因子对肠纵平滑肌毒蕈碱受体的影响存在差异。这些发现解释了在炎症的Th1和Th2模型中观察到的肌肉收缩力改变的基础，以及在线虫感染后的状态。
The extent to which gut motility and smooth muscle contractility are altered by intestinal inflammation depends on the nature of the underlying immune activation. The muscarinic receptor on smooth muscle plays a critical role in mediating acetylcholine- driven motor function. We examined the ability of cytokines to influence muscarinic receptor characteristics on intestinal longitudinal muscle and related the findings to studies on carbacholinduced contraction. Cells were isolated from longitudinal muscle myenteric plexus ( LMMP). Cytokine receptor expression, muscle contractility, and muscarinic agonist receptor characteristics were examined by agonist displacement of [ N- methyl-H-3] scopolamine ([H-3] NMS) binding. The TGF-beta 1 receptor ( 543 bp) and the IFN-gamma receptor 1 ( 660 bp) were identified on smooth muscle cells. Scatchard analysis revealed dissociation constant and maximum binding values for [H-3] NMS of 2.6 nM and 2.4 x 10(4) sites/ cell, respectively, in control cells. Nematode infection was accompanied by a reduction in inhibitory constant of the high-affinity sites ( K-H), and this was independent of signal transduction and activator of transcription 6. Preincubation with TGF-beta 1 enhanced longitudinal muscle contractility and decreased the K-H to 2.2 pM ( increased muscarinic receptor affinity), whereas preincubation with IFN-gamma increased the K-H to 0.4 mu M ( decreased muscarinic receptor affinity) and decreased longitudinal muscle contractility. Preincubation of LMMP with IL- 13 decreased the K-H to 0.2 nM. Cytokines exert differential effects on the muscarinic receptor on intestinal longitudinal smooth muscle. These findings explain the basis for altered muscle contractility observed in Th1 and Th2 models of inflammation, as well as in the post- nematode- infected state.