Tilapia (Oreochromis mossambicus) brain cells respond to hyperosmotic challenge by inducing myo-inositol biosynthesis
Tilapia (Oreochromis mossambicus) brain cells respond to hyperosmotic challenge by inducing myo-inositol biosynthesis
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DOI：
10.1242/jeb.088906
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发表时间：
2013-12-01
影响因子：
2.8
通讯作者：
Kueltz, Dietmar
中科院分区：
文献类型：
--
作者：
Gardell, Alison M.;Yang, Jun;Kueltz, Dietmar
本研究旨在确定急性（25 ppt）和慢性（30，60和90 ppt）盐度驯化后莫桑比克罗非鱼（Oreochromis mossambicus）脑中从头肌醇生物合成（MIB）途径的调节。MIB途径在响应高渗挑战而在细胞中积累相容的渗透剂肌醇中起重要作用，并且由两种酶组成，肌醇磷酸合酶和肌醇单磷酸酶。在罗非鱼脑中，MIB酶的转录调节被发现以时间（急性适应）或剂量（慢性适应）依赖的方式稳健地增加。血浆渗透压和Na+和Cl-浓度也进行了测量，并显着增加，在急性和慢性盐度的挑战。有趣的是，MIB酶mRNA和血浆渗透压之间的高度显着的正相关关系，发现在急性和慢性盐度驯化。此外，建立了一种质谱分析方法，并用于定量罗非鱼脑中的总肌醇浓度，这密切反映了高渗MIB途径的诱导。因此，肌醇是一种主要的相容性渗压剂，当暴露于急性和慢性高渗挑战时，其在脑细胞中积累。这些数据表明，MIB途径是高度诱导的罗非鱼脑中的环境盐度的挑战，这种诱导可能是由血浆渗透压的增加。由于MIB途径使用葡萄糖-6-磷酸作为底物，并且正在合成大量的肌醇，因此我们的数据还说明MIB途径可能有助于盐度挑战所带来的高能量需求。
This study aimed to determine the regulation of the de novo myo-inositol biosynthetic (MIB) pathway in Mozambique tilapia (Oreochromis mossambicus) brain following acute (25 ppt) and chronic (30, 60 and 90 ppt) salinity acclimations. The MIB pathway plays an important role in accumulating the compatible osmolyte, myo-inositol, in cells in response to hyperosmotic challenge and consists of two enzymes, myo-inositol phosphate synthase and inositol monophosphatase. In tilapia brain, MIB enzyme transcriptional regulation was found to robustly increase in a time (acute acclimation) or dose (chronic acclimation) dependent manner. Blood plasma osmolality and Na+ and Cl- concentrations were also measured and significantly increased in response to both acute and chronic salinity challenges. Interestingly, highly significant positive correlations were found between MIB enzyme mRNA and blood plasma osmolality in both acute and chronic salinity acclimations. Additionally, a mass spectrometry assay was established and used to quantify total myo-inositol concentration in tilapia brain, which closely mirrored the hyperosmotic MIB pathway induction. Thus, myo-inositol is a major compatible osmolyte that is accumulated in brain cells when exposed to acute and chronic hyperosmotic challenge. These data show that the MIB pathway is highly induced in response to environmental salinity challenge in tilapia brain and that this induction is likely prompted by increases in blood plasma osmolality. Because the MIB pathway uses glucose-6-phosphate as a substrate and large amounts of myo-inositol are being synthesized, our data also illustrate that the MIB pathway likely contributes to the high energetic demand posed by salinity challenge.