Auditory hair cells(HCs)are the mechanosensory receptors of the cochlea,and HC loss or malfunction can result from genetic defects.Dock4,a member of the Dock180-related protein superfamily,is a guanine nucleotide exch...Auditory hair cells(HCs)are the mechanosensory receptors of the cochlea,and HC loss or malfunction can result from genetic defects.Dock4,a member of the Dock180-related protein superfamily,is a guanine nucleotide exchange factor for Rac1,and previous reports have shown that Dock4 mutations are associated with autism spectrum disorder,myelodysplastic syndromes,and tumorigenesis.Here,we found that Dock4 is highly expressed in the cochlear HCs of mice.However,the role of Dock4 in the inner ear has not yet been investigated.Taking advantage of the piggyBac transposon system,Dock4 knockdown(KD)mice were established to explore the role of Dock4 in the cochlea.Compared to wild-type controls,Dock4 KD mice showed significant hearing impairment from postnatal day 60.Dock4 KD mice showed hair bundle deficits and increased oxidative stress,which eventually led to HC apoptosis,late-onset HC loss,and progressive hearing loss.Furthermore,molecular mechanism studies showed that Rac1/β-catenin signaling was significantly downregulated in Dock4 KD cochleae and that this was the cause for the disorganized stereocilia and increased oxidative stress in HCs.Overall,our work demonstrates that the Dock4/Rac1/β-catenin signaling pathway plays a critical role in the maintenance of auditory HCs and hearing function.展开更多
基金This work was supported by grants from National Key R&D Program of China(2021YFA1101300,2020YFA0112503,2020YFA0113600)the Strategic Priority Research Program of the Chinese Academy of Science(XDA16010303)+5 种基金the National Natural Science Foundation of China(82030029,81970882,82071013,81870721,92149304,82000984)the Natural Science Foundation of Jiangsu Province(BE2019711)the Science and Technology Department of Sichuan Province(2021YFS0371)the Shenzhen Fundamental Research Program(JCYJ20190814093401920,JCYJ20210324125608022)the China National Postdoctoral Program for Innovative Talents(BX20200082)the Open Research Fund of State Key Laboratory of Genetic Engineering,Fudan University(SKLGE-2109).
文摘Auditory hair cells(HCs)are the mechanosensory receptors of the cochlea,and HC loss or malfunction can result from genetic defects.Dock4,a member of the Dock180-related protein superfamily,is a guanine nucleotide exchange factor for Rac1,and previous reports have shown that Dock4 mutations are associated with autism spectrum disorder,myelodysplastic syndromes,and tumorigenesis.Here,we found that Dock4 is highly expressed in the cochlear HCs of mice.However,the role of Dock4 in the inner ear has not yet been investigated.Taking advantage of the piggyBac transposon system,Dock4 knockdown(KD)mice were established to explore the role of Dock4 in the cochlea.Compared to wild-type controls,Dock4 KD mice showed significant hearing impairment from postnatal day 60.Dock4 KD mice showed hair bundle deficits and increased oxidative stress,which eventually led to HC apoptosis,late-onset HC loss,and progressive hearing loss.Furthermore,molecular mechanism studies showed that Rac1/β-catenin signaling was significantly downregulated in Dock4 KD cochleae and that this was the cause for the disorganized stereocilia and increased oxidative stress in HCs.Overall,our work demonstrates that the Dock4/Rac1/β-catenin signaling pathway plays a critical role in the maintenance of auditory HCs and hearing function.
