Tipsmark C K, Jørgensen C, Brande-Lavridsen N, Engelund M, Olesen J H, Madsen S S
Institute of Biology, University of Southern Denmark, 5230 Odense M, Denmark.
Gen Comp Endocrinol. 2009 Sep 15;163(3):270-7. doi: 10.1016/j.ygcen.2009.04.020. Epub 2009 May 3.
We recently showed that a series of tight junction proteins of the claudin family are regulated in the gill of salmon during salinity acclimation. The aim of the present study was to investigate the role of cortisol, growth hormone (GH) and prolactin (PRL) on regulation of expression of these isoforms. Experiments on primary cultures of gill tissue showed that cortisol stimulates claudin 10e, 27a and 30 mRNA levels while no significant effects were observed on claudin 28a and 28b. The associated receptor signalling pathway was examined using glucocorticoid and mineralocorticoid receptor antagonists RU486 and spironolactone, respectively. The observed in vitro responses were blocked by RU486, suggesting the involvement of a glucocorticoid type receptor. Injections of FW salmon with cortisol increased the expression of claudin 10e, 27a, and 30 but did not affect claudin 28a and 28b significantly. While GH had no effect on its own, the combination of GH and cortisol reduced claudin 28b levels. Injection of SW salmon with PRL selectively increased the expression of claudin 28a but had no effect on the other examined isoforms. The data shows that FW- (27a and 30) and SW-induced (10e) claudins are all stimulated by cortisol while the major osmoregulatory hormones GH and PRL had no effect on these salinity sensitive isoforms. This suggests that other hormones and/or osmotic conditions interact with cortisol to determine claudin composition in the gill.
我们最近发现，在鲑鱼适应盐度变化的过程中，紧密连接蛋白家族的一系列蛋白在鳃中受到调控。本研究的目的是探究皮质醇、生长激素（GH）和催乳素（PRL）在这些异构体表达调控中的作用。鳃组织原代培养实验表明，皮质醇可刺激claudin 10e、27a和30的mRNA水平，而对claudin 28a和28b未观察到显著影响。分别使用糖皮质激素和盐皮质激素受体拮抗剂RU486和螺内酯检测相关受体信号通路。观察到的体外反应被RU486阻断，表明涉及糖皮质激素型受体。给淡水鲑鱼注射皮质醇可增加claudin 10e、27a和30的表达，但对claudin 28a和28b没有显著影响。虽然生长激素单独作用时没有影响，但生长激素和皮质醇的组合降低了claudin 28b的水平。给海水鲑鱼注射催乳素可选择性增加claudin 28a的表达，但对其他检测的异构体没有影响。数据表明，淡水诱导（27a和30）和海水诱导（10e）的claudin均受到皮质醇的刺激，而主要的渗透压调节激素生长激素和催乳素对这些盐度敏感异构体没有影响。这表明其他激素和/或渗透条件与皮质醇相互作用，以确定鳃中claudin的组成。
