Urea transporter B (UT-B) is a membrane channel protein widely distributed in mammals and plays a significant physiological role by regulating urea and water transportation in different tissues. More and more studies have found that UT-B is related to neurological diseases, including myelinopathy and depression. Urea is accumulated in the brains of UT-B knockout mice, the synaptic plasticity of neurons is reduced, and the morphology and function of glial cells are also changed. However, the distribution and expression change of UT-B remain unclear. The purpose of this study was to determine the expression characteristics of UT-B in brain. Through single-cell RNA sequencing, UT-B was found to express universally and substantially throughout the various cells in central nervous system except endothelial and smooth muscle cells. UT-B was detected in third cerebral ventricular wall, granule cell layer of the dentate gyrus and other parts of hippocampal, cerebral cortex, substantia nigra, habenular and lateral hypothalamic nucleus by immunohistochemistry. Compared with the membrane expression of UT-B in glial cells, the subcellular localization of UT-B is in the Golgi apparatus of neurons. Further, the expression of UT-B was regulated by osmotic pressure in vitro. In the experimental traumatic brain injury model (TBI), the number of UT-B positive neurons near the ipsilateral cerebral cortex increased first and then decreased over time, peaking at 24th hour. We inferred that change in UT-B expression after TBI was adaption to changed urea level. The experimental data suggest that UT-B may be a potential target for the treatment of TBI and white matter edema.

中文翻译：

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尿素转运蛋白B在正常脑和受伤脑中的表达

尿素转运蛋白B（UT-B）是一种广泛分布在哺乳动物中的膜通道蛋白，通过调节尿素和水在不同组织中的运输而发挥重要的生理作用。越来越多的研究发现UT-B与神经系统疾病有关，包括脊髓病和抑郁症。尿素积聚在UT-B基因敲除小鼠的大脑中，神经元的突触可塑性降低，神经胶质细胞的形态和功能也发生变化。但是，UT-B的分布和表达变化仍不清楚。这项研究的目的是确定UT-B在大脑中的表达特征。通过单细胞RNA测序，发现UT-B在内皮细胞和平滑肌细胞以外的中枢神经系统中的所有细胞中普遍表达。免疫组化法检测到第三脑室壁，齿状回的颗粒细胞层以及海马，大脑皮层，黑质，下丘脑和下丘脑外侧核的其他部位的UT-B。与UT-B在胶质细胞中的膜表达相比，UT-B的亚细胞定位在神经元的高尔基体中。此外，UT-B的表达在体外受渗透压调节。在实验性创伤性脑损伤模型（TBI）中，同侧大脑皮层附近的UT-B阳性神经元数量随时间先增加然后减少，在第24小时达到峰值。我们推断，TBI后UT-B表达的变化是适应尿素水平的变化。实验数据表明，UT-B可能是治疗TBI和白质水肿的潜在靶标。