Gap junction mediated intercellular metabolite transfer in the cochlea is compromised in connexin30 null mice.
Gap junction mediated intercellular metabolite transfer in the cochlea is compromised in connexin30 null mice.
复制标题
DOI：
10.1371/journal.pone.0004088
复制
发表时间：
2008
期刊：
影响因子：
3.7
通讯作者：
Lin X
中科院分区：
文献类型：
--
作者：
Chang Q;Tang W;Ahmad S;Zhou B;Lin X
Connexin26 (Cx26) 和 connexin30 (Cx30) 是两个主要的蛋白质亚基，它们在耳蜗中共同组装形成间隙连接 (GJ)。其中任何一种突变都是人类非综合征性语前耳聋的主要原因。由于 Cx 突变引起的耳蜗发病机制尚不清楚，我们研究了 Cx30 无效突变对小鼠耳蜗中 GJ 介导的离子和代谢耦合的影响。一种新型扁平耳蜗制剂用于直接评估耳蜗感觉上皮细胞间的耦合。双电极膜片钳记录显示，Cx30 的缺失并没有显着改变耳蜗支持细胞中的 GJ 电导。保留的电耦合与免疫标记数据一致，显示突变小鼠耳蜗中有大量 Cx26 GJ。相反，染料扩散测定表明，在 Cx30 缺失小鼠中，多种荧光染料（包括不可代谢的 D-葡萄糖类似物，2-NBDG）在耳蜗支持细胞之间的细胞间转移的速率和程度严重降低。由于耳蜗中的感觉上皮是无血管器官，GJ 促进的营养物质和信号分子的细胞间转移可能在细胞稳态中发挥重要作用。为了测试这种可能性，使用 NBDG 作为示踪剂来研究 GJ 在全身输送时将葡萄糖转运到耳蜗感觉上皮的贡献。 Cx30 缺失小鼠的耳蜗支持细胞对 NBDG 的摄取显着减少。 GJ 阻滞剂或葡萄糖竞争也观察到这种减少，支持了我们测试的特异性。这些数据表明 GJ 促进支持细胞有效摄取葡萄糖。这项研究提供了第一个直接的实验证据，表明耳蜗支持细胞中代谢重要分子的转移依赖于 GJ 的正常功能，从而提示耳蜗中 Cx 突变相关耳聋的新发病机制。
Connexin26 (Cx26) and connexin30 (Cx30) are two major protein subunits that co-assemble to form gap junctions (GJs) in the cochlea. Mutations in either one of them are the major cause of non-syndromic prelingual deafness in humans. Because the mechanisms of cochlear pathogenesis caused by Cx mutations are unclear, we investigated effects of Cx30 null mutation on GJ-mediated ionic and metabolic coupling in the cochlea of mice. A novel flattened cochlear preparation was used to directly assess intercellular coupling in the sensory epithelium of the cochlea. Double-electrode patch clamp recordings revealed that the absence of Cx30 did not significantly change GJ conductance among the cochlear supporting cells. The preserved electrical coupling is consistent with immunolabeling data showing extensive Cx26 GJs in the cochlea of the mutant mice. In contrast, dye diffusion assays showed that the rate and extent of intercellular transfer of multiple fluorescent dyes (including a non-metabolizable D-glucose analogue, 2-NBDG) among cochlear supporting cells were severely reduced in Cx30 null mice. Since the sensory epithelium in the cochlea is an avascular organ, GJ-facilitated intercellular transfer of nutrient and signaling molecules may play essential roles in cellular homeostasis. To test this possibility, NBDG was used as a tracer to study the contribution of GJs in transporting glucose into the cochlear sensory epithelium when delivered systemically. NBDG uptake in cochlear supporting cells was significantly reduced in Cx30 null mice. The decrease was also observed with GJ blockers or glucose competition, supporting the specificity of our tests. These data indicate that GJs facilitate efficient uptake of glucose in the supporting cells. This study provides the first direct experimental evidence showing that the transfer of metabolically-important molecules in cochlear supporting cells is dependent on the normal function of GJs, thereby suggesting a novel pathogenesis process in the cochlea for Cx-mutation-linked deafness.
登录
查看更多内容
DOI：
10.1007/bf00186783
发表时间：
1995-02-01
期刊：
ANATOMY AND EMBRYOLOGY
影响因子：
--
作者：
KIKUCHI, T;KIMURA, RS;ADAMS, JC
通讯作者：
ADAMS, JC
影响因子：
5.3
作者：
Kirkland, RA;Franklin, JL
通讯作者：
Franklin, JL
影响因子：
--
作者：
STERKERS, O;SAUMON, G;AMIEL, C
通讯作者：
AMIEL, C
影响因子：
3.9
作者：
ROYALL, JA;ISCHIROPOULOS, H
通讯作者：
ISCHIROPOULOS, H
影响因子：
7.8
作者：
Gabriel, HD;Jung, D;Bützler, C;Temme, A;Traub, O;Winterhager, E;Willecke, K
通讯作者：
Willecke, K