CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.
Laboratory of Clinical Regenerative Medicine, Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
Biochem Pharmacol. 2020 Jul;177:113954. doi: 10.1016/j.bcp.2020.113954. Epub 2020 Apr 3.
The choroid plexus (CP) epithelial cells establish an important blood-brain interface, the blood-cerebrospinal fluid barrier (BCSFB), which constitutes a complementary gateway to the blood-brain-barrier for the entrance of several molecules into the central nervous system (CNS). However, the mechanisms that operate at the BCSFB to regulate the molecular traffic are still poorly understood. The taste signalling machinery, present in many extra-oral tissues, is involved in the chemical sensing of the composition of body fluids. We have identified this pathway in rat CP and hypothesised that it could also be present in the human BCSFB. In this study, we characterised the bitter taste receptors (TAS2Rs) expression profiling in human CP by combining data retrieved from available databases of the human CP transcriptome with its expression analysis in a human CP cell line and immunohistochemistry of human CP sections from men and women. TAS2R4, 5, 14 and 39 expression was confirmed in human CP tissue by immunohistochemistry and in HIBCPP cells by RT-PCR, immunofluorescence and Western blot. Moreover, the presence of downstream effector proteins GNAT3, PLCβ2 and TRPM5 was also detected in HIBCPP cells. Then, we demonstrated that HIBCPP cells respond to chloramphenicol via TAS2R39 and to quercetin via TAS2R14. Our findings support an active role of TAS2Rs at the human BCSFB, as surveyors of the bloodstream and CSF compositions. These findings open new avenues for studies on the uptake of relevant compounds for targeted therapies of the CNS.
脉络丛上皮细胞在血脑界面建立了一个重要的血脑屏障（BCSFB），该屏障构成了血脑屏障的互补门户，允许多种分子进入中枢神经系统（CNS）。然而，BCSFB 调节分子运输的机制仍知之甚少。味觉信号通路存在于许多口腔外组织中，参与体液成分的化学感应。我们已经在大鼠脉络丛中发现了这条通路，并假设它也可能存在于人类 BCSFB 中。在这项研究中，我们通过结合人类脉络丛转录组数据库中的数据和对人类脉络丛细胞系的表达分析，以及对男性和女性人类脉络丛切片的免疫组织化学分析，对人类脉络丛中的苦味受体（TAS2R）表达谱进行了描述。通过免疫组织化学和 RT-PCR、免疫荧光和 Western blot 在 HIBCPP 细胞中证实了 TAS2R4、5、14 和 39 在人类脉络丛组织中的表达。此外，在 HIBCPP 细胞中还检测到下游效应蛋白 GNAT3、PLCβ2 和 TRPM5 的存在。然后，我们证明 HIBCPP 细胞通过 TAS2R39 对氯霉素做出反应，通过 TAS2R14 对槲皮素做出反应。我们的发现支持 TAS2R 在人类 BCSFB 中的积极作用，作为血液和 CSF 成分的监测者。这些发现为针对 CNS 的靶向治疗中相关化合物摄取的研究开辟了新的途径。
