C-Terminal End of Aquaporin 0 Regulates Lens Gap Junction Channel Function.
C-Terminal End of Aquaporin 0 Regulates Lens Gap Junction Channel Function.
复制标题
水通道蛋白 0 的 C 末端调节晶状体间隙连接通道功能。
DOI：
10.1167/iovs.19-26787
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发表时间：
2019
影响因子：
4.4
通讯作者：
Kumari,Sindhu
中科院分区：
文献类型：
--
作者：
Varadaraj,Kulandaiappan;Gao,Junyuan;Mathias,RichardT;Kumari,Sindhu
目的：我们以前报道过水通道蛋白0（AQP 0）调节透镜纤维细胞间隙连接（GJ）通道功能。方法：建立AQP 0 ΔC/ΔC小鼠模型，使其在透镜中表达1-263个氨基酸的AQP 0，并在晶状体中表达1-246个氨基酸的AQP 0。评估了透镜的透明度和聚焦。测量细胞内阻抗以确定GJ耦合电阻。还测定了细胞内流体静压（HP）。Western blotting检测连接蛋白结果：出生后10天，AQP 0 ΔC/ΔC小鼠晶状体相对于年龄匹配的野生型晶状体显示透明度丧失和异常光学畸变;在分化过程中，GJ耦合阻力增加。透镜HP在分化和成熟纤维细胞交界处增加约1.5倍，在中央增加约2.0倍; Cx46和Cx 50的表达水平无明显变化（P> 0.05）。结论：GJ偶联抵抗的增加与Cx46和Cx 50表达的降低无关，提示斑块的开放概率降低或斑块位置发生了物理变化。阻力的增加显著大于HP的增加，表明通过每个开放GJ通道的压力驱动水流较少。这些变化可能导致透明度损失和异常光学失真。总体而言，我们的数据表明AQP 0的C末端参与调节GJ偶联以维持透镜透明度和体内平衡。
Purpose: We reported previously that aquaporin 0 (AQP0) modulates lens fiber cell gap junction (GJ) channel function. The present study was conducted to find out whether the C-terminal end of AQP0 is involved in this regulation.Methods: A mouse model, AQP0 ΔC/ΔC, was genetically engineered to express AQP0 with 1-246 amino acids, without the normal intact AQP0 (1-263 amino acids) in the lens. Transparency and focusing of the lens were assessed. Intracellular impedance was measured to determine GJ coupling resistance. Intracellular hydrostatic pressure (HP) was also determined. Western blotting was performed to determine connexin (Cx46 and Cx50) expression levels.Results: At postnatal day 10, AQP0 ΔC/ΔC mouse lenses relative to age-matched wild-type lenses showed loss of transparency and abnormal optical distortion; GJ coupling resistance increased in the differentiating (1.6-fold) and mature (8-fold) fiber cells; lens HP increased approximately 1.5-fold at the junction between the differentiating and mature fiber cells and approximately 2.0-fold in the center; there was no significant change (P> 0.05) in expression levels of Cx46 or Cx50.Conclusions: The increase in GJ coupling resistance was not associated with reduced connexin expression, suggesting either a reduction in the open probability or some physical change in plaque location. The increase in resistance was significantly greater than the increase in HP, suggesting less pressure-driven water flow through each open GJ channel. These changes may lead to a loss of transparency and abnormal optical distortion. Overall, our data demonstrate the C-terminal end of AQP0 is involved in modulating GJ coupling to maintain lens transparency and homeostasis.