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Shen Y, Hu H, Fan C, Wang Q, Zou T, Ye B, Xiang M. Sensorineural hearing loss may lead to dementia-related pathological changes in hippocampal neurons. Neurobiol Dis 2021; 156:105408. [PMID: 34082124 DOI: 10.1016/j.nbd.2021.105408] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/26/2021] [Accepted: 05/26/2021] [Indexed: 01/23/2023] Open
Abstract
Presbycusis contributes to cognitive decline and Alzheimer's disease. However, most research in this area involves clinical observations and statistical modeling, and few studies have examined the relationship between hearing loss and the molecular changes that lead to cognitive dysfunction. The present study investigated whether hearing loss contributes to dementia in the absence of aging and noise using a mouse model of severe bilateral hearing loss induced by kanamycin (1000 mg/kg) and furosemide (400 mg/kg). Immunohistochemistry, silver staining, immunofluorescence analysis, and Western blotting were used to observe pathological changes in different regions of the hippocampus in animals with hearing loss. Changes in the cognitive function of animals with hearing loss were assessed using the Morris water maze test. The results showed that neurons began to degenerate 60 days after hearing loss, and this degeneration was accompanied by structural disorganization and decreased neurogenesis. The level of phosphorylated tau increased over time. Increases in escape latency and distance traveled during the training phase of the Morris water maze test were observed 90 days after hearing loss. Activated microglia and astrocytes with increased levels of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were detected in the hippocampus. These results suggest that hearing loss alone causes neuronal degeneration, inhibition of neurogenesis, increased tau protein phosphorylation, and increased neuroinflammation in the hippocampus. Early intervention in individuals with hearing loss may reduce the risk of cognitive decline.
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Affiliation(s)
- Yilin Shen
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Haixia Hu
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Cui Fan
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Quan Wang
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Tianyuan Zou
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Bin Ye
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Mingliang Xiang
- Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
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Basu U, Balakrishnan SS, Janardan V, Raghu P. A PI4KIIIα protein complex is required for cell viability during Drosophila wing development. Dev Biol 2020; 462:208-222. [PMID: 32194035 DOI: 10.1016/j.ydbio.2020.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/06/2020] [Accepted: 03/07/2020] [Indexed: 01/02/2023]
Abstract
Phosphatidylinositol 4 phosphate (PI4P) and phosphatidylinositol 4,5 bisphosphate [PI(4,5)P2] are enriched on the inner leaflet of the plasma membrane and proposed to be key determinants of its function. PI4P is also the biochemical precursor for the synthesis of PI(4,5)P2 but can itself also bind to and regulate protein function. However, the independent function of PI4P at the plasma membrane in supporting cell function in metazoans during development in vivo remains unclear. We find that conserved components of a multi-protein complex composed of phosphatidylinositol 4-kinase IIIα (PI4KIIIα), TTC7 and Efr3 is required for normal vein patterning and wing development. Depletion of each of these three components of the PI4KIIIα complex in developing wing cells results in altered wing morphology. These effects are associated with an increase in apoptosis and can be rescued by expression of an inhibitor of Drosophila caspase. We find that in contrast to previous reports, PI4KIIIα depletion does not alter key outputs of hedgehog signalling in developing wing discs. Depletion of PI4KIIIα results in reduced PI4P levels at the plasma membrane of developing wing disc cells while levels of PI(4,5)P2, the downstream metabolite of PI4P, are not altered. Thus, PI4P itself generated by the activity of the PI4KIIIα complex plays an essential role in supporting cell viability in the developing Drosophila wing disc.
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Affiliation(s)
- Urbashi Basu
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India
| | - Sruthi S Balakrishnan
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India
| | - Vishnu Janardan
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India
| | - Padinjat Raghu
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India.
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Ye B, Wang Q, Hu H, Shen Y, Fan C, Chen P, Ma Y, Wu H, Xiang M. Restoring autophagic flux attenuates cochlear spiral ganglion neuron degeneration by promoting TFEB nuclear translocation via inhibiting MTOR. Autophagy 2019; 15:998-1016. [PMID: 30706760 PMCID: PMC6526833 DOI: 10.1080/15548627.2019.1569926] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Macroautophagy/autophagy dysfunction is associated with many neurodegenerative diseases. TFEB (transcription factor EB), an important molecule that regulates lysosomal and autophagy function, is regarded as a potential target for treating some neurodegenerative diseases. However, the relationship between autophagy dysfunction and spiral ganglion neuron (SGN) degeneration and the role of TFEB in SGN degeneration has not yet been established. Here, we showed that in degenerated SGNs, induced by sensory epithelial cell loss in the cochlea of mice following kanamycin and furosemide administration, the lipofuscin area and oxidative stress level were increased, the nuclear-to-cytoplasmic TFEB ratio was decreased, and the late stage of autophagic flux was impaired. After autophagy dysfunction was partially ameliorated with an MTOR inhibitor, which promoted TFEB translocation into the nucleus from the cytoplasm, we found that the lysosomal deficits were significantly relieved, the oxidative stress level was reduced, and the density of surviving SGNs and auditory nerve fibers was increased. The results in the present study reveal that autophagy dysfunction is an important component of SGN degeneration, and TFEB may be a potential target for attenuating SGN degeneration following sensory epithelial cell loss in the cochlea of mice. Abbreviations: 3-NT: 3-nitrotyrosine; 4-HNE: 4-hydroxynonenal; 8-OHdG: 8-hydroxy-2ʹ-deoxyguanosine; ABR: auditory brainstem response; APP: amyloid beta (A4) precursor protein; CLEAR: coordinated lysosomal expression and regulation; CTSB: cathespin B; CTSD: cathespin D; SAMR1: senescence-accelerated mouse/resistance 1; SAMP8: senescence-accelerated mouse/prone 8; MAPK1/ERK2: mitogen-activated protein kinase 1; MTOR: mechanistic target of rapamycin kinase; SGN: spiral ganglion neuron; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscope; TFEB: transcription factor EB
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Affiliation(s)
- Bin Ye
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Quan Wang
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Haixia Hu
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Yilin Shen
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Cui Fan
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Penghui Chen
- b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Yan Ma
- b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Hao Wu
- b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
| | - Mingliang Xiang
- a Department of Otolaryngology & Head and Neck Surgery, Ruijin Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,b Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, The Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Ear Institute , Shanghai Jiao tong University School of Medicine , Shanghai , China
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Fu X, Sun X, Zhang L, Jin Y, Chai R, Yang L, Zhang A, Liu X, Bai X, Li J, Wang H, Gao J. Tuberous sclerosis complex-mediated mTORC1 overactivation promotes age-related hearing loss. J Clin Invest 2018; 128:4938-4955. [PMID: 30247156 DOI: 10.1172/jci98058] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 08/08/2018] [Indexed: 12/29/2022] Open
Abstract
The underlying molecular mechanisms of age-related hearing loss (ARHL) in humans and many strains of mice have not been fully characterized. This common age-related disorder is assumed to be closely associated with oxidative stress. Here, we demonstrate that mTORC1 signaling is highly and specifically activated in the cochlear neurosensory epithelium (NSE) in aging mice, and rapamycin injection prevents ARHL. To further examine the specific role of mTORC1 signaling in ARHL, we generated murine models with NSE-specific deletions of Raptor or Tsc1, regulators of mTORC1 signaling. Raptor-cKO mice developed hearing loss considerably more slowly than WT littermates. Conversely, Tsc1 loss led to the early-onset death of cochlear hair cells and consequently accelerated hearing loss. Tsc1-cKO cochleae showed features of oxidative stress and impaired antioxidant defenses. Treatment with rapamycin and the antioxidant N-acetylcysteine rescued Tsc1-cKO hair cells from injury in vivo. In addition, we identified the peroxisome as the initial signaling organelle involved in the regulation of mTORC1 signaling in cochlear hair cells. In summary, our findings identify overactive mTORC1 signaling as one of the critical causes of ARHL and suggest that reduction of mTORC1 activity in cochlear hair cells may be a potential strategy to prevent ARHL.
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Affiliation(s)
- Xiaolong Fu
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Xiaoyang Sun
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Linqing Zhang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Yecheng Jin
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Renjie Chai
- Key Laboratory for Development Genes and Human Disease, Southeast University, Nanjing, China
| | - Lili Yang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Aizhen Zhang
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China.,Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Xiangguo Liu
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Xiaochun Bai
- State Key Laboratory of Organ Failure Research, Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jianfeng Li
- Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Haibo Wang
- Department of Otolaryngology-Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Jiangang Gao
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
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