脑室下区（SVZ）是脑部的一个区域，含有神经干细胞（NSCs）和祖细胞（NPCs），这些细胞在哺乳动物成年期间生成新的神经元和胶质细胞。最近的数据表明，SVZ NSCs是恶性胶质瘤最具侵袭性的形式脑胶质母细胞瘤（GBM）中最初获得的致癌突变细胞类型。SVZ的NSCs/NPCs表现出半胱氨酸/甘氨酸渗透孔功能，其功能尚未完全阐明。在这项研究中，我们旨在分析半胱氨酸/甘氨酸渗透孔介导的通讯是否会影响SVZ NPCs和GBM细胞的增殖。为此，我们使用了从苦樟树（Peumus boldus）提取的生物碱boldine，它能抑制蛋白质连接素和泛素渗透孔，但不影响间隙连接通讯。将50 μM boldine溶液处理大鼠SVZ NPCs培养为神经球体时，有效抑制了半胱氨酸/甘氨酸渗透孔的染料摄取，并显著减小了神经球体的直径和溴脱氧尿嘧啶（BrdU）的摄取。然而，处理并未改变分化模式。以D4蛋白亚单位形成的半胱氨酸/甘氨酸渗透孔（D4）或泛素渗透孔1（probenecid）为靶标进行的实验表明，probenecid但不是D4，与boldine获得相似的BrdU摄取减少作用。这些结果表明，泛素渗透孔1的抑制可能在boldine对SVZ NPCs的抗增殖作用中起到部分作用。对不同类型的原代人类GBM细胞（GBM59，GBM96和U87-MG）进行boldine（25-600 μM）处理的实验显示，boldine的浓度呈现降低GBM细胞生长的趋势。boldine处理还显著抑制了GBM细胞的半胱氨酸/甘氨酸渗透孔的活性。总的来说，我们提供了boldine在SVZ NPCs和GBM细胞中抗有丝分裂作用的证据，这可能部分归因于其抑制半胱氨酸/甘氨酸渗透孔的功能。这些结果对于未来有可能抑制经手术切除后仍存在于脑部的突变NSCs或胶质瘤干细胞增殖的GBM的策略可能具有重要意义。版权所有 © 2023 Jiménez-Madrona、Morado-Díaz、Talaverón、Tabernero、Pastor、Sáez和Matarredona。

The subventricular zone (SVZ) is a brain region that contains neural stem cells and progenitor cells (NSCs/NPCs) from which new neurons and glial cells are formed during adulthood in mammals. Recent data indicate that SVZ NSCs are the cell type that acquires the initial tumorigenic mutation in glioblastoma (GBM), the most aggressive form of malignant glioma. NSCs/NPCs of the SVZ present hemichannel activity whose function has not yet been fully elucidated. In this work, we aimed to analyze whether hemichannel-mediated communication affects proliferation of SVZ NPCs and GBM cells.For that purpose, we used boldine, an alkaloid derived from the boldo tree (Peumus boldus), that inhibits connexin and pannexin hemichannels, but without affecting gap junctional communication. Boldine treatment (50 μM) of rat SVZ NPCs grown as neurospheres effectively inhibited dye uptake through hemichannels and induced a significant reduction in neurosphere diameter and in bromodeoxyuridine (BrdU) incorporation. However, the differentiation pattern was not modified by the treatment. Experiments with specific blockers for hemichannels formed by connexin subunits (D4) or pannexin 1 (probenecid) revealed that probenecid, but not D4, produced a decrease in BrdU incorporation similar to that obtained with boldine. These results suggest that inhibition of pannexin 1 hemichannels could be partially responsible for the antiproliferative effect of boldine on SVZ NPCs. Analysis of the effect of boldine (25-600 μM) on different types of primary human GBM cells (GBM59, GBM96, and U87-MG) showed a concentration-dependent decrease in GBM cell growth. Boldine treatment also induced a significant inhibition of hemichannel activity in GBM cells.Altogether, we provide evidence of an antimitotic action of boldine in SVZ NPCs and in GBM cells which may be due, at least in part, to its hemichannel blocking function. These results could be of relevance for future possible strategies in GBM aimed to suppress the proliferation of mutated NSCs or glioma stem cells that might remain in the brain after tumor resection.Copyright © 2023 Jiménez-Madrona, Morado-Díaz, Talaverón, Tabernero, Pastor, Sáez and Matarredona.