Prestin-Dependence of Outer Hair Cell Survival and Partial Rescue of Outer Hair Cell Loss in PrestinV499G/Y501H Knockin Mice.
Prestin-Dependence of Outer Hair Cell Survival and Partial Rescue of Outer Hair Cell Loss in PrestinV499G/Y501H Knockin Mice.
复制标题
Prestinv499g/Y501H敲击蛋白小鼠中外毛细胞存活的普雷斯汀依赖性和外部毛细胞损失的部分营救。
DOI：
10.1371/journal.pone.0145428
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Zheng J
中科院分区：
文献类型：
--
作者：
Cheatham MA;Edge RM;Homma K;Leserman EL;Dallos P;Zheng J
创建表达突变 prestin V499G/Y501H (499 prestin) 的敲入 (KI) 小鼠来研究耳蜗放大。该突变体中分离的外毛细胞（OHC）的记录显示电动性大大降低，因此听力敏感性降低。尽管 499 个 prestin OHC 的硬度正常，并且比缺乏 prestin 的 OHC 更长，但相对于 prestin 敲除 (KO) 小鼠中记录的情况，意外地观察到了加速的 OHC 死亡。这些观察结果表明，除了已知的哺乳动物耳蜗放大需求之外，prestin 在 OHC 维持中还发挥着额外作用。为了深入了解 prestin 相关的 OHC 损失，我们实施了多种干预措施来提高生存率。首先，将 499 个 prestin KI 与缺乏线粒体促凋亡基因 Bak 的 Bak KO 小鼠回交。由于氧化应激与 OHC 死亡有关，因此另一组 499 只 prestin KI 小鼠被喂食抗氧化剂饮食 Protandim。 499 KI 小鼠也与 FVB 小鼠品系回交，该品系在成年期仍保持出色的高频听力，以减少与原始 499 prestin KI 相关的与年龄相关的听力损失的复合效应。最后，还创建了表达一份 499 prestin 和一份 KO prestin 的复合杂合 (chet) 小鼠，以减少 499 prestin 蛋白的数量。结果显示，在 FVB 背景下，小鼠和 499 个 prestin KI 的 OHC 死亡减少，但接受 Protandim 的小鼠 OHC 存活率仅略有改善。我们还报告说，499 个 prestin KI 中 OHC 存活率的提高对听力表型几乎没有影响，重申了关于 prestin 运动功能在耳蜗放大中的重要作用的最初论点。
A knockin (KI) mouse expressing mutated prestin V499G/Y501H (499 prestin) was created to study cochlear amplification. Recordings from isolated outer hair cells (OHC) in this mutant showed vastly reduced electromotility and, as a consequence, reduced hearing sensitivity. Although 499 prestin OHCs were normal in stiffness and longer than OHCs lacking prestin, accelerated OHC death was unexpectedly observed relative to that documented in prestin knockout (KO) mice. These observations imply an additional role of prestin in OHC maintenance besides its known requirement for mammalian cochlear amplification. In order to gain mechanistic insights into prestin-associated OHC loss, we implemented several interventions to improve survival. First, 499 prestin KI’s were backcrossed to Bak KO mice, which lack the mitochondrial pro-apoptotic gene Bak. Because oxidative stress is implicated in OHC death, another group of 499 prestin KI mice was fed the antioxidant diet, Protandim. 499 KI mice were also backcrossed onto the FVB murine strain, which retains excellent high-frequency hearing well into adulthood, to reduce the compounding effect of age-related hearing loss associated with the original 499 prestin KIs. Finally, a compound heterozygous (chet) mouse expressing one copy of 499 prestin and one copy of KO prestin was also created to reduce quantities of 499 prestin protein. Results show reduction in OHC death in chets, and in 499 prestin KIs on the FVB background, but only a slight improvement in OHC survival for mice receiving Protandim. We also report that improved OHC survival in 499 prestin KIs had little effect on hearing phenotype, reaffirming the original contention about the essential role of prestin’s motor function in cochlear amplification.