Bu Chuan, Xu Lei, Han Yuechen, Wang Man, Wang Xue, Liu Wenwen, Chai Renjie, Wang Haibo
Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.
Shandong Institute of Otorhinolaryngology, Jinan, Shandong, China.
Cell Death Discov. 2022 Feb 24;8(1):78. doi: 10.1038/s41420-022-00879-9.
The transcription factor c-Myb is vital for cell survival, proliferation, differentiation, and apoptosis. We have previously reported that c-Myb knockdown exacerbates neomycin-induced damage to cochlea cells. However, the function and regulation of c-Myb in the mammalian inner ear remains unclear. Here, we first found that the expression of c-Myb in cochlear HCs was downregulated after cisplatin damage in vivo. Next, to investigate the role of c-Myb in HCs treated with cisplatin, the recombinant virus AAV-ie-CAG-Myb-HA (AAV-c-Myb) that overexpresses c-Myb was constructed and transfected into HCs. The protein expression of c-Myb was effectively up-regulated in cultured cochlear HCs after the virus transfection, which increased cochlear HC viability, decreased HC apoptosis and reduced intracellular reactive oxygen species (ROS) levels after cisplatin injury in vitro. The overexpression of c-Myb in HCs after AAV-c-Myb transfection in vivo also promoted HC survival, improved the hearing function of mice and reduced HC apoptosis after cisplatin injury. Furthermore, c-Myb-HC conditional knockout mice (Prestin; c-Myb-cKO) in which c-Myb expression is downregulated only in cochlear OHCs were generated and the cisplatin-induced HCs loss, apoptosis and hearing deficit were all exacerbated in Prestin; c-Myb-cKO mice treated with cisplatin in vivo. Finally, mechanistic studies showed that upregulation of the PI3K/Akt signaling pathway by c-Myb contributed to the increased HC survival after cisplatin exposure in vitro. The findings from this work suggest that c-Myb might serve as a new target for the prevention of cisplatin-induced HC damage and hearing loss.
转录因子c-Myb对细胞存活、增殖、分化和凋亡至关重要。我们之前报道过，c-Myb基因敲低会加剧新霉素诱导的耳蜗细胞损伤。然而，c-Myb在哺乳动物内耳中的功能和调控仍不清楚。在此，我们首先发现，体内顺铂损伤后，耳蜗毛细胞中c-Myb的表达下调。接下来，为了研究c-Myb在顺铂处理的毛细胞中的作用，构建了过表达c-Myb的重组病毒AAV-ie-CAG-Myb-HA（AAV-c-Myb）并转染到毛细胞中。病毒转染后，培养的耳蜗毛细胞中c-Myb的蛋白表达有效上调，这增加了耳蜗毛细胞的活力，减少了毛细胞凋亡，并降低了体外顺铂损伤后细胞内活性氧（ROS）水平。体内AAV-c-Myb转染后，毛细胞中c-Myb的过表达也促进了毛细胞存活，改善了小鼠的听力功能，并减少了顺铂损伤后的毛细胞凋亡。此外，构建了c-Myb毛细胞条件性敲除小鼠（Prestin；c-Myb-cKO），其中c-Myb表达仅在耳蜗外毛细胞中下调，体内用顺铂处理的Prestin；c-Myb-cKO小鼠中，顺铂诱导的毛细胞损失、凋亡和听力缺陷均加剧。最后，机制研究表明，c-Myb上调PI3K/Akt信号通路有助于体外顺铂暴露后毛细胞存活增加。这项工作的研究结果表明，c-Myb可能作为预防顺铂诱导的毛细胞损伤和听力损失的新靶点。
