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Rincon Sabatino S, Sangaletti R, Griswold A, Dietrich WD, King CS, Rajguru SM. Transcriptional response to mild therapeutic hypothermia in noise-induced cochlear injury. Front Neurosci 2024; 17:1296475. [PMID: 38298897 PMCID: PMC10827921 DOI: 10.3389/fnins.2023.1296475] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/18/2023] [Indexed: 02/02/2024] Open
Abstract
Introduction Prevention or treatment for acoustic injury has been met with many translational challenges, resulting in the absence of FDA-approved interventions. Localized hypothermia following noise exposure mitigates acute cochlear injury and may serve as a potential avenue for therapeutic approaches. However, the mechanisms by which hypothermia results in therapeutic improvements are poorly understood. Methods This study performs the transcriptomic analysis of cochleae from juvenile rats that experienced noise-induced hearing loss (NIHL) followed by hypothermia or control normothermia treatment. Results Differential gene expression results from RNA sequencing at 24 h post-exposure to noise suggest that NIHL alone results in increased inflammatory and immune defense responses, involving complement activation and cytokine-mediated signaling. Hypothermia treatment post-noise, in turn, may mitigate the acute inflammatory response. Discussion This study provides a framework for future research to optimize hypothermic intervention for ameliorating hearing loss and suggests additional pathways that could be targeted for NIHL therapeutic intervention.
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Affiliation(s)
| | - Rachele Sangaletti
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Anthony Griswold
- Department of Human Genetics, University of Miami, Coral Gables, FL, United States
| | - W. Dalton Dietrich
- The Miami Project to Cure Paralysis, University of Miami, Coral Gables, FL, United States
| | | | - Suhrud M. Rajguru
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
- The Miami Project to Cure Paralysis, University of Miami, Coral Gables, FL, United States
- RestorEar Devices LLC, Bozeman, MT, United States
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2
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Zhang C, Ye M, Bush P, Hu BH. Heterogeneity in macrophages along the cochlear spiral in mice: insights from SEM and functional analyses. Front Cell Neurosci 2023; 17:1222074. [PMID: 37692550 PMCID: PMC10485373 DOI: 10.3389/fncel.2023.1222074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/31/2023] [Indexed: 09/12/2023] Open
Abstract
The susceptibility of sensory cells to pathological conditions differs between the apical and basal regions of the cochlea, and the cochlear immune system may contribute to this location-dependent variability. Our previous study found morphological differences in basilar membrane macrophages between the apical and basal regions of the cochlea. However, the details of this site-dependent difference and its underlying structural and biological basis are not fully understood. In this study, we utilized scanning electron microscopy to examine the ultrastructure of macrophages and their surrounding supporting structures. Additionally, we examined the phagocytic activities of macrophages and the expression of immune molecules in both apical and basal regions of the cochlea. We employed two mouse strains (C57BL/6J and B6.129P-Cx3cr1tm1Litt/J) and evaluated three experimental conditions: young normal (1-4 months), aging (11-19 months), and noise-induced damage (120 dB SPL for 1 h). Using scanning electron microscopy, we revealed location-specific differences in basilar membrane macrophage morphology and surface texture, architecture in mesothelial cell layers, and spatial correlation between macrophages and mesothelial cells in both young and older mice. Observations of macrophage phagocytic activities demonstrated that basal macrophages exhibited greater phagocytic activities in aging and noise-damaged ears. Furthermore, we identified differences in the expression of immune molecules between the apical and basal cochlear tissues of young mice. Finally, our study demonstrated that as the cochlea ages, macrophages in the apical and basal regions undergo a transformation in their morphologies, with apical macrophages acquiring certain basal macrophage features and vice versa. Overall, our findings demonstrate apical and basal differences in macrophage phenotypes and functionality, which are related to distinct immune and structural differences in the macrophage surrounding tissues.
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Affiliation(s)
- Celia Zhang
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, United States
- Department of Audiology, University of the Pacific, San Francisco, CA, United States
| | - Mengxiao Ye
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, United States
| | - Peter Bush
- South Campus Instrument Center, University at Buffalo, Buffalo, NY, United States
| | - Bo Hua Hu
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, United States
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3
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Rahman MT, Bailey EM, Gansemer BM, Pieper AA, Manak JR, Green SH. Anti-inflammatory Therapy Protects Spiral Ganglion Neurons After Aminoglycoside Antibiotic-Induced Hair Cell Loss. Neurotherapeutics 2023; 20:578-601. [PMID: 36697994 PMCID: PMC10121993 DOI: 10.1007/s13311-022-01336-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2022] [Indexed: 01/26/2023] Open
Abstract
Destruction of cochlear hair cells by aminoglycoside antibiotics leads to gradual death of the spiral ganglion neurons (SGNs) that relay auditory information to the brain, potentially limiting the efficacy of cochlear implants. Because the reasons for this cochlear neurodegeneration are unknown, there are no neuroprotective strategies for patients. To investigate this problem, we assessed transcriptomic changes in the rat spiral ganglion following aminoglycoside antibiotic (kanamycin)-induced hair cell destruction. We observed selectively increased expression of immune and inflammatory response genes and increased abundance of activated macrophages in spiral ganglia by postnatal day 32 in kanamycin-deafened rats, preceding significant SGN degeneration. Treatment with the anti-inflammatory medications dexamethasone and ibuprofen diminished long-term SGN degeneration. Ibuprofen and dexamethasone also diminished macrophage activation. Efficacy of ibuprofen treatment was augmented by co-administration of the nicotinamide adenine dinucleotide-stabilizing agent P7C3-A20. Our results support a critical role of neuroinflammation in SGN degeneration after aminoglycoside antibiotic-mediated cochlear hair cell loss, as well as a neuroprotective strategy that could improve cochlear implant efficacy.
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Affiliation(s)
- Muhammad T Rahman
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Erin M Bailey
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
| | | | - Andrew A Pieper
- Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
- Department of Psychiatry, Case Western Reserve University, Cleveland, OH, 44106, USA
- Geriatric Psychiatry, GRECC, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, 44106, USA
- Institute for Transformative Molecular Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - J Robert Manak
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
- Department of Pediatrics, University of Iowa, Iowa City, IA, 52242, USA
| | - Steven H Green
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA.
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4
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Ke W, Lu Z, Zhao X. NOB1: A Potential Biomarker or Target in Cancer. Curr Drug Targets 2020; 20:1081-1089. [PMID: 30854959 DOI: 10.2174/1389450120666190308145346] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/06/2019] [Accepted: 03/05/2019] [Indexed: 12/18/2022]
Abstract
Human NIN1/RPN12 binding protein 1 homolog (NOB1), an RNA binding protein, is expressed ubiquitously in normal tissues such as the lung, liver, and spleen. Its core physiological function is to regulate protease activities and participate in maintaining RNA metabolism and stability. NOB1 is overexpressed in a variety of cancers, including pancreatic cancer, non-small cell lung cancer, ovarian cancer, prostate carcinoma, osteosarcoma, papillary thyroid carcinoma, colorectal cancer, and glioma. Although existing data indicate that NOB1 overexpression is associated with cancer growth, invasion, and poor prognosis, the molecular mechanisms behind these effects and its exact roles remain unclear. Several studies have confirmed that NOB1 is clinically relevant in different cancers, and further research at the molecular level will help evaluate the role of NOB1 in tumors. NOB1 has become an attractive target in anticancer therapy because it is overexpressed in many cancers and mediates different stages of tumor development. Elucidating the role of NOB1 in different signaling pathways as a potential cancer treatment will provide new ideas for existing cancer treatment methods. This review summarizes the research progress made into NOB1 in cancer in the past decade; this information provides valuable clues and theoretical guidance for future anticancer therapy by targeting NOB1.
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Affiliation(s)
- Weiwei Ke
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004, LN, China
| | - Zaiming Lu
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004, LN, China
| | - Xiangxuan Zhao
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004, LN, China
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5
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Escabi CD, Frye MD, Trevino M, Lobarinas E. The rat animal model for noise-induced hearing loss. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3692. [PMID: 31795685 PMCID: PMC7480078 DOI: 10.1121/1.5132553] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Rats make excellent models for the study of medical, biological, genetic, and behavioral phenomena given their adaptability, robustness, survivability, and intelligence. The rat's general anatomy and physiology of the auditory system is similar to that observed in humans, and this has led to their use for investigating the effect of noise overexposure on the mammalian auditory system. The current paper provides a review of the rat model for studying noise-induced hearing loss and highlights advancements that have been made using the rat, particularly as these pertain to noise dose and the hazardous effects of different experimental noise types. In addition to the traditional loss of auditory function following acoustic trauma, recent findings have indicated the rat as a useful model in observing alterations in neuronal processing within the central nervous system following noise injury. Furthermore, the rat provides a second animal model when investigating noise-induced cochlear synaptopathy, as studies examining this in the rat model resemble the general patterns observed in mice. Together, these findings demonstrate the relevance of this animal model for furthering the authors' understanding of the effects of noise on structural, anatomical, physiological, and perceptual aspects of hearing.
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Affiliation(s)
- Celia D Escabi
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
| | - Mitchell D Frye
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
| | - Monica Trevino
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
| | - Edward Lobarinas
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
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6
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Ke W, Lu Z, Zhao X. NOB1: A Potential Biomarker or Target in Cancer. Curr Drug Targets 2019; 20:1081-1089. [DOI: doi10.2174/1389450120666190308145346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/06/2019] [Accepted: 03/05/2019] [Indexed: 09/01/2023]
Abstract
Human NIN1/RPN12 binding protein 1 homolog (NOB1), an RNA binding protein, is expressed ubiquitously in normal tissues such as the lung, liver, and spleen. Its core physiological function is to regulate protease activities and participate in maintaining RNA metabolism and stability. NOB1 is overexpressed in a variety of cancers, including pancreatic cancer, non-small cell lung cancer, ovarian cancer, prostate carcinoma, osteosarcoma, papillary thyroid carcinoma, colorectal cancer, and glioma. Although existing data indicate that NOB1 overexpression is associated with cancer growth, invasion, and poor prognosis, the molecular mechanisms behind these effects and its exact roles remain unclear. Several studies have confirmed that NOB1 is clinically relevant in different cancers, and further research at the molecular level will help evaluate the role of NOB1 in tumors. NOB1 has become an attractive target in anticancer therapy because it is overexpressed in many cancers and mediates different stages of tumor development. Elucidating the role of NOB1 in different signaling pathways as a potential cancer treatment will provide new ideas for existing cancer treatment methods. This review summarizes the research progress made into NOB1 in cancer in the past decade; this information provides valuable clues and theoretical guidance for future anticancer therapy by targeting NOB1.
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Affiliation(s)
- Weiwei Ke
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004, LN, China
| | - Zaiming Lu
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004, LN, China
| | - Xiangxuan Zhao
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004, LN, China
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Schiavon E, Smalley JL, Newton S, Greig NH, Forsythe ID. Neuroinflammation and ER-stress are key mechanisms of acute bilirubin toxicity and hearing loss in a mouse model. PLoS One 2018; 13:e0201022. [PMID: 30106954 PMCID: PMC6091913 DOI: 10.1371/journal.pone.0201022] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 07/07/2018] [Indexed: 12/01/2022] Open
Abstract
Hyperbilirubinemia (jaundice) is caused by raised levels of unconjugated bilirubin in the blood. When severe, susceptible brain regions including the cerebellum and auditory brainstem are damaged causing neurological sequelae such as ataxia, hearing loss and kernicterus. The mechanism(s) by which bilirubin exerts its toxic effect have not been completely understood to date. In this study we investigated the acute mechanisms by which bilirubin causes the neurotoxicity that contributes to hearing loss. We developed a novel mouse model that exhibits the neurological features seen in human Bilirubin-Induced Neurological Dysfunction (BIND) syndrome that we assessed with a behavioural score and auditory brainstem responses (ABR). Guided by initial experiments applying bilirubin to cultured cells in vitro, we performed whole genome gene expression measurements on mouse brain tissue (cerebellum and auditory brainstem) following bilirubin exposure to gain mechanistic insights into biochemical processes affected, and investigated further using immunoblotting. We then compared the gene changes induced by bilirubin to bacterial lipopolysaccharide (LPS), a well characterized inducer of neuroinflammation, to assess the degree of similarity between them. Finally, we examined the extent to which genetic perturbation of inflammation and both known and novel anti-inflammatory drugs could protect hearing from bilirubin-induced toxicity. The in vitro results indicated that bilirubin induces changes in gene expression consistent with endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR). These gene changes were similar to the gene expression signature of thapsigargin–a known ER stress inducer. It also induced gene expression changes associated with inflammation and NF-κB activation. The in vivo model showed behavioural impairment and a raised auditory threshold. Whole genome gene expression analysis confirmed inflammation as a key mechanism of bilirubin neurotoxicity in the auditory pathway and shared gene expression hallmarks induced by exposure to bacterial lipopolysaccharide (LPS) a well-characterized inducer of neuroinflammation. Interestingly, bilirubin caused more severe damage to the auditory system than LPS in this model, but consistent with our hypothesis of neuroinflammation being a primary part of bilirubin toxicity, the hearing loss was protected by perturbing the inflammatory response. This was carried out genetically using lipocalin-2 (LCN2)-null mice, which is an inflammatory cytokine highly upregulated in response to bilirubin. Finally, we tested known and novel anti-inflammatory compounds (interfering with NF-κB and TNFα signalling), and also demonstrated protection of the auditory system from bilirubin toxicity. We have developed a novel, reversible, model for jaundice that shows movement impairment and auditory loss consistent with human symptoms. We used this model to establish ER-stress and inflammation as major contributors to bilirubin toxicity. Because of the rapid and reversible onset of toxicity in this novel model it represents a system to screen therapeutic compounds. We have demonstrated this by targeting inflammation genetically and with anti-inflammatory small molecules that offered protection against bilirubin toxicity. This also suggests that anti-inflammatory drugs could be of therapeutic use in hyperbilirubinemia.
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Affiliation(s)
- Emanuele Schiavon
- Department Neuroscience, Psychology & Behaviour, University of Leicester, Leicester, Leicestershire, United Kingdom
| | - Joshua L. Smalley
- Department Neuroscience, Psychology & Behaviour, University of Leicester, Leicester, Leicestershire, United Kingdom
| | - Sherylanne Newton
- Department Neuroscience, Psychology & Behaviour, University of Leicester, Leicester, Leicestershire, United Kingdom
| | - Nigel H. Greig
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, United States of America
| | - Ian D. Forsythe
- Department Neuroscience, Psychology & Behaviour, University of Leicester, Leicester, Leicestershire, United Kingdom
- * E-mail:
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8
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Gröschel M, Basta D, Ernst A, Mazurek B, Szczepek AJ. Acute Noise Exposure Is Associated With Intrinsic Apoptosis in Murine Central Auditory Pathway. Front Neurosci 2018; 12:312. [PMID: 29867323 PMCID: PMC5954103 DOI: 10.3389/fnins.2018.00312] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 04/23/2018] [Indexed: 01/08/2023] Open
Abstract
Noise that is capable of inducing the hearing loss (NIHL) has a strong impact on the inner ear structures and causes early and most obvious pathophysiological changes in the auditory periphery. Several studies indicated that intrinsic apoptotic cell death mechanisms are the key factors inducing cellular degeneration immediately after noise exposure and are maintained for days or even weeks. In addition, studies demonstrated several changes in the central auditory system following noise exposure, consistent with early apoptosis-related pathologies. To clarify the underlying mechanisms, the present study focused on the noise-induced gene and protein expression of the pro-apoptotic protease activating factor-1 (APAF1) and the anti-apoptotic B-cell lymphoma 2 related protein a1a (BCL2A1A) in the cochlear nucleus (CN), inferior colliculus (IC) and auditory cortex (AC) of the murine central auditory pathway. The expression of Bcl2a1a mRNA was upregulated immediately after trauma in all tissues investigated, whereas the protein levels were significantly reduced at least in the auditory brainstem. Conversely, acute noise has decreased the expression of Apaf1 gene along the auditory pathway. The changes in APAF1 protein level were not statistically significant. It is tempting to speculate that the acoustic overstimulation leads to mitochondrial dysfunction and induction of apoptosis by regulation of proapoptotic and antiapoptotic proteins. The inverse expression pattern on the mRNA level of both genes might reflect a protective response to decrease cellular damage. Our results indicate the immediate presence of intrinsic apoptosis following noise trauma. This, in turn, may significantly contribute to the development of central structural deficits. Auditory pathway-specific inhibition of intrinsic apoptosis could be a therapeutic approach for the treatment of acute (noise-induced) hearing loss to prevent irreversible neuronal injury in auditory brain structures and to avoid profound deficits in complex auditory processing.
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Affiliation(s)
- Moritz Gröschel
- Department of Otolaryngology, Unfallkrankenhaus Berlin, Charité Medical School, Berlin, Germany
| | - Dietmar Basta
- Department of Otolaryngology, Unfallkrankenhaus Berlin, Charité Medical School, Berlin, Germany
| | - Arne Ernst
- Department of Otolaryngology, Unfallkrankenhaus Berlin, Charité Medical School, Berlin, Germany
| | - Birgit Mazurek
- Tinnitus Center, Berlin Institute of Health, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Agnieszka J Szczepek
- Department of Otorhinolaryngology, Head and Neck Surgery, Berlin Institute of Health, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
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9
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Nikopoulos K, Farinelli P, Giangreco B, Tsika C, Royer-Bertrand B, Mbefo M, Bedoni N, Kjellström U, El Zaoui I, Di Gioia S, Balzano S, Cisarova K, Messina A, Decembrini S, Plainis S, Blazaki S, Khan M, Micheal S, Boldt K, Ueffing M, Moulin A, Cremers F, Roepman R, Arsenijevic Y, Tsilimbaris M, Andréasson S, Rivolta C. Mutations in CEP78 Cause Cone-Rod Dystrophy and Hearing Loss Associated with Primary-Cilia Defects. Am J Hum Genet 2016; 99:770-776. [PMID: 27588451 DOI: 10.1016/j.ajhg.2016.07.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/07/2016] [Indexed: 02/08/2023] Open
Abstract
Cone-rod degeneration (CRD) belongs to the disease spectrum of retinal degenerations, a group of hereditary disorders characterized by an extreme clinical and genetic heterogeneity. It mainly differentiates from other retinal dystrophies, and in particular from the more frequent disease retinitis pigmentosa, because cone photoreceptors degenerate at a higher rate than rod photoreceptors, causing severe deficiency of central vision. After exome analysis of a cohort of individuals with CRD, we identified biallelic mutations in the orphan gene CEP78 in three subjects from two families: one from Greece and another from Sweden. The Greek subject, from the island of Crete, was homozygous for the c.499+1G>T (IVS3+1G>T) mutation in intron 3. The Swedish subjects, two siblings, were compound heterozygotes for the nearby mutation c.499+5G>A (IVS3+5G>A) and for the frameshift-causing variant c.633delC (p.Trp212Glyfs(∗)18). In addition to CRD, these three individuals had hearing loss or hearing deficit. Immunostaining highlighted the presence of CEP78 in the inner segments of retinal photoreceptors, predominantly of cones, and at the base of the primary cilium of fibroblasts. Interaction studies also showed that CEP78 binds to FAM161A, another ciliary protein associated with retinal degeneration. Finally, analysis of skin fibroblasts derived from affected individuals revealed abnormal ciliary morphology, as compared to that of control cells. Altogether, our data strongly suggest that mutations in CEP78 cause a previously undescribed clinical entity of a ciliary nature characterized by blindness and deafness but clearly distinct from Usher syndrome, a condition for which visual impairment is due to retinitis pigmentosa.
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Abstract
The identification of transcriptional differences has served as an important starting point in understanding the molecular mechanisms behind biological processes and systems. The developmental biology of the inner ear, the biology of hearing and of course the pathology of deafness are all processes that warrant a molecular description if we are to improve human health. To this end, technological innovation has meant that larger scale analysis of gene transcription has been possible for a number of years now, extending our molecular analysis of genes to beyond those that are currently in vogue for a given system. In this review, some of the contributions gene profiling has made to understanding developmental, pathological and physiological processes in the inner ear are highlighted.
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Affiliation(s)
- Thomas Schimmang
- Instituto de Biología y Genética MolecularUniversidad de Valladolid y Consejo Superior de Investigaciones CientíficasValladolidSpain
| | - Mark Maconochie
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
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11
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Melgar–Rojas P, Alvarado JC, Fuentes–Santamaría V, Gabaldón–Ull MC, Juiz JM. Validation of Reference Genes for RT-qPCR Analysis in Noise-Induced Hearing Loss: A Study in Wistar Rat. PLoS One 2015; 10:e0138027. [PMID: 26366995 PMCID: PMC4569353 DOI: 10.1371/journal.pone.0138027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/24/2015] [Indexed: 12/26/2022] Open
Abstract
The reverse transcriptase–quantitative polymerase chain reaction (RT–qPCR) requires adequate normalization in order to ensure accurate results. The use of reference genes is the most common method to normalize RT–qPCR assays; however, many studies have reported that the expression of frequently used reference genes is more variable than expected, depending on experimental conditions. Consequently, proper validation of the stability of reference genes is an essential step when performing new gene expression studies. Despite the fact that RT–qPCR has been widely used to elucidate molecular correlates of noise–induced hearing loss (NIHL), up to date there are no reports demonstrating validation of reference genes for the evaluation of changes in gene expression after NIHL. Therefore, in this study we evaluated the expression of some commonly used reference genes (Arbp, b–Act, b2m, CyA, Gapdh, Hprt1, Tbp, Tfrc and UbC) and examined their suitability as endogenous control genes for RT–qPCR analysis in the adult Wistar rat in response to NIHL. Four groups of rats were noise–exposed to generate permanent cochlear damage. Cochleae were collected at different time points after noise exposure and the expression level of candidate reference genes was evaluated by RT–qPCR using geNorm, NormFinder and BestKeeper software to determine expression stability. The three independent applications revealed Tbp as the most stably expressed reference gene. We also suggest a group of top–ranked reference genes that can be combined to obtain suitable reference gene pairs for the evaluation of the effects of noise on gene expression in the cochlea. These findings provide essential basis for further RT–qPCR analysis in studies of NIHL using Wistar rats as animal model.
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Affiliation(s)
- Pedro Melgar–Rojas
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, University of Castilla–La Mancha, Campus in Albacete, Albacete, Spain
- * E-mail:
| | - Juan Carlos Alvarado
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, University of Castilla–La Mancha, Campus in Albacete, Albacete, Spain
| | - Verónica Fuentes–Santamaría
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, University of Castilla–La Mancha, Campus in Albacete, Albacete, Spain
| | - María Cruz Gabaldón–Ull
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, University of Castilla–La Mancha, Campus in Albacete, Albacete, Spain
| | - José M. Juiz
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), School of Medicine, University of Castilla–La Mancha, Campus in Albacete, Albacete, Spain
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Yang S, Cai Q, Bard J, Jamison J, Wang J, Yang W, Hu BH. Variation analysis of transcriptome changes reveals cochlear genes and their associated functions in cochlear susceptibility to acoustic overstimulation. Hear Res 2015; 330:78-89. [PMID: 26024952 DOI: 10.1016/j.heares.2015.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/04/2015] [Accepted: 04/10/2015] [Indexed: 10/23/2022]
Abstract
Individual variation in the susceptibility of the auditory system to acoustic overstimulation has been well-documented at both the functional and structural levels. However, the molecular mechanism responsible for this variation is unclear. The current investigation was designed to examine the variation patterns of cochlear gene expression using RNA-seq data and to identify the genes with expression variation that increased following acoustic trauma. This study revealed that the constitutive expressions of cochlear genes displayed diverse levels of gene-specific variation. These variation patterns were altered by acoustic trauma; approximately one-third of the examined genes displayed marked increases in their expression variation. Bioinformatics analyses revealed that the genes that exhibited increased variation were functionally related to cell death, biomolecule metabolism, and membrane function. In contrast, the stable genes were primarily related to basic cellular processes, including protein and macromolecular syntheses and transport. There was no functional overlap between the stable and variable genes. Importantly, we demonstrated that glutamate metabolism is related to the variation in the functional response of the cochlea to acoustic overstimulation. Taken together, the results indicate that our analyses of the individual variations in transcriptome changes of cochlear genes provide important information for the identification of genes that potentially contribute to the generation of individual variation in cochlear responses to acoustic overstimulation.
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Affiliation(s)
- Shuzhi Yang
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Qunfeng Cai
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Jonathan Bard
- Next-Generation Sequencing and Expression Analysis Core, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, 14263, USA.
| | - Jennifer Jamison
- Next-Generation Sequencing and Expression Analysis Core, New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, 14263, USA.
| | - Jianmin Wang
- Department of Biostatistics and Bioinformatics, Roswell Park Cancer Institute, Elm & Carlton Streets, Buffalo, NY, 14263, USA.
| | - Weiping Yang
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
| | - Bo Hua Hu
- Center for Hearing and Deafness, University at Buffalo, NY, 14214, USA.
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Jensen JB, Lysaght AC, Liberman MC, Qvortrup K, Stankovic KM. Immediate and delayed cochlear neuropathy after noise exposure in pubescent mice. PLoS One 2015; 10:e0125160. [PMID: 25955832 PMCID: PMC4425526 DOI: 10.1371/journal.pone.0125160] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/20/2015] [Indexed: 12/12/2022] Open
Abstract
Moderate acoustic overexposure in adult rodents is known to cause acute loss of synapses on sensory inner hair cells (IHCs) and delayed degeneration of the auditory nerve, despite the completely reversible temporary threshold shift (TTS) and morphologically intact hair cells. Our objective was to determine whether a cochlear synaptopathy followed by neuropathy occurs after noise exposure in pubescence, and to define neuropathic versus non-neuropathic noise levels for pubescent mice. While exposing 6 week old CBA/CaJ mice to 8-16 kHz bandpass noise for 2 hrs, we defined 97 dB sound pressure level (SPL) as the threshold for this particular type of neuropathic exposure associated with TTS, and 94 dB SPL as the highest non-neuropathic noise level associated with TTS. Exposure to 100 dB SPL caused permanent threshold shift although exposure of 16 week old mice to the same noise is reported to cause only TTS. Amplitude of wave I of the auditory brainstem response, which reflects the summed activity of the cochlear nerve, was complemented by synaptic ribbon counts in IHCs using confocal microscopy, and by stereological counts of peripheral axons and cell bodies of the cochlear nerve from 24 hours to 16 months post exposure. Mice exposed to neuropathic noise demonstrated immediate cochlear synaptopathy by 24 hours post exposure, and delayed neurodegeneration characterized by axonal retraction at 8 months, and spiral ganglion cell loss at 8-16 months post exposure. Although the damage was initially limited to the cochlear base, it progressed to also involve the cochlear apex by 8 months post exposure. Our data demonstrate a fine line between neuropathic and non-neuropathic noise levels associated with TTS in the pubescent cochlea.
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Affiliation(s)
- Jane Bjerg Jensen
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, 02114, United States of America
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, 02115, United States of America
- Department of Biomedical Sciences, CFIM, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Andrew C. Lysaght
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, 02114, United States of America
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, 02115, United States of America
- Program in Speech and Hearing Bioscience and Technology, Division of Health Science and Technology, Harvard and Massachusetts Institute of Technology, Boston, MA, 02139, United States of America
| | - M. Charles Liberman
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, 02114, United States of America
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, 02115, United States of America
- Program in Speech and Hearing Bioscience and Technology, Division of Health Science and Technology, Harvard and Massachusetts Institute of Technology, Boston, MA, 02139, United States of America
| | - Klaus Qvortrup
- Department of Biomedical Sciences, CFIM, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Konstantina M. Stankovic
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, 02114, United States of America
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, 02115, United States of America
- Program in Speech and Hearing Bioscience and Technology, Division of Health Science and Technology, Harvard and Massachusetts Institute of Technology, Boston, MA, 02139, United States of America
- * E-mail:
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Physiological, anatomical, and behavioral changes after acoustic trauma in Drosophila melanogaster. Proc Natl Acad Sci U S A 2013; 110:15449-54. [PMID: 24003166 DOI: 10.1073/pnas.1307294110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Noise-induced hearing loss (NIHL) is a growing health issue, with costly treatment and lost quality of life. Here we establish Drosophila melanogaster as an inexpensive, flexible, and powerful genetic model system for NIHL. We exposed flies to acoustic trauma and quantified physiological and anatomical effects. Trauma significantly reduced sound-evoked potential (SEP) amplitudes and increased SEP latencies in control genotypes. SEP amplitude but not latency effects recovered after 7 d. Although trauma produced no gross morphological changes in the auditory organ (Johnston's organ), mitochondrial cross-sectional area was reduced 7 d after exposure. In nervana 3 heterozygous flies, which slightly compromise ion homeostasis, trauma had exaggerated effects on SEP amplitude and mitochondrial morphology, suggesting a key role for ion homeostasis in resistance to acoustic trauma. Thus, Drosophila exhibit acoustic trauma effects resembling those found in vertebrates, including inducing metabolic stress in sensory cells. This report of noise trauma in Drosophila is a foundation for studying molecular and genetic sequelae of NIHL.
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Cai Q, Wang B, Patel M, Yang SM, Hu BH. RNAlater facilitates microdissection of sensory cell-enriched samples from the mouse cochlea for transcriptional analyses. J Neurosci Methods 2013; 219:240-51. [PMID: 23958750 DOI: 10.1016/j.jneumeth.2013.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/03/2013] [Accepted: 08/05/2013] [Indexed: 10/26/2022]
Abstract
Molecular analyses of cochlear pathology rely on the acquisition of high-quality cochlear samples. For small rodents, isolating sensory cell-enriched samples with well-preserved RNA integrity for transcriptional analyses poses a significant challenge. Here, we report a microdissection technique for isolating sensory cell-enriched samples from the cochlea. We found that treating the tissue with RNAlater, a RNA preservation medium, alters the physical properties of the tissue and facilitates the dissection. Unlike previous samples that have been isolated from the sensory epithelium, our samples contain defined cell populations that have a consistent ratio of sensory cells to supporting cells. Importantly, the RNA components were well preserved. With this microdissection method, we collected three types of samples: sensory cell-enriched, outer hair cell-enriched, and inner hair cell-enriched. To demonstrate the feasibility of the method, we screened multiple reference genes in the sensory cell-enriched samples and identified stable genes in noise-traumatized cochleae. The method described here balances the need for both quality and purity of sensory cells and also circumvents many limitations of the currently available techniques for collecting cochlear tissues. With our approach, the collected samples can be used in diverse downstream analyses, including qRT-PCR, microarray, and RNA sequencing.
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Affiliation(s)
- Qunfeng Cai
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA
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Kou ZZ, Qu J, Zhang DL, Li H, Li YQ. Noise-induced hearing loss is correlated with alterations in the expression of GABAB receptors and PKC gamma in the murine cochlear nucleus complex. Front Neuroanat 2013; 7:25. [PMID: 23908607 PMCID: PMC3726868 DOI: 10.3389/fnana.2013.00025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 07/11/2013] [Indexed: 01/08/2023] Open
Abstract
Noise overexposure may induce permanent noise-induced hearing loss (NIHL). The cochlear nucleus complex (CNC) is the entry point for sensory information in the central auditory system. Impairments in gamma-aminobutyric acid (GABA)—mediated synaptic transmission in the CNC have been implicated in the pathogenesis of auditory disorders. However, the role of protein kinase C (PKC) signaling pathway in GABAergic inhibition in the CNC in NIHL remains elusive. Thus, we investigated the alterations of glutamic acid decarboxylase 67 (GAD67, the chemical marker for GABA-containing neurons), PKC γ subunit (PKCγ) and GABAB receptor (GABABR) expression in the CNC using transgenic GAD67-green fluorescent protein (GFP) knock-in mice, BALB/c mice and C57 mice. Immunohistochemical results indicate that the GFP-labeled GABAergic neurons were distributed in the molecular layer (ML) and fusiform cell layer (FCL) of the dorsal cochlear nucleus (DCN). We found that 69.91% of the GFP-positive neurons in the DCN were immunopositive for both PKCγ and GABABR1. The GAD67-positive terminals made contacts with PKCγ/GABABR1 colocalized neurons. Then we measured the changes of auditory thresholds in mice after noise exposure for 2 weeks, and detected the GAD67, PKCγ, and GABABR expression at mRNA and protein levels in the CNC. With noise over-exposure, there was a reduction in GABABR accompanied by an increase in PKCγ expression, but no significant change in GAD67 expression. In summary, our results demonstrate that alterations in the expression of PKCγ and GABABRs may be involved in impairments in GABAergic inhibition within the CNC and the development of NIHL.
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Affiliation(s)
- Zhen-Zhen Kou
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
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High-throughput technologies for gene expression analyses: what we have learned for noise-induced cochlear degeneration? J Otol 2013; 8:25-31. [PMID: 26236335 DOI: 10.1016/s1672-2930(13)50003-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Noise-induced hearing loss is a common cause of acquired hearing loss in the adult population. Acoustic overstimulation causes cochlear damage through mechanical stress to the tissue. Consequently, complex molecular changes are initiated, and these changes lead to morphological and biological alterations in the cochlea, which in turn compromise the cochlear function and cause hearing loss. In the past 10 years, there have been significant advances in our understanding of the molecular mechanisms of noise-induced hearing loss. These advances are attributed, in part, to the development of high-throughput technologies for the global analyses of molecular changes. In this review, we briefly describe the newly developed methods for investigating the molecular responses of the cochlea to acoustic trauma and the knowledge generated from these studies. We also discuss the strengths and limitations of each technique and the major challenges to investigate cochlear degeneration following acoustic injury.
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Transcriptome characterization by RNA-Seq reveals the involvement of the complement components in noise-traumatized rat cochleae. Neuroscience 2013; 248:1-16. [PMID: 23727008 DOI: 10.1016/j.neuroscience.2013.05.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 05/16/2013] [Accepted: 05/21/2013] [Indexed: 12/12/2022]
Abstract
Acoustic trauma, a leading cause of sensorineural hearing loss in adults, induces a complex degenerative process in the cochlea. Although previous investigations have identified multiple stress pathways, a comprehensive analysis of cochlear responses to acoustic injury is still lacking. In the current study, we used the next-generation RNA-sequencing (RNA-Seq) technique to sequence the whole transcriptome of the normal and noise-traumatized cochlear sensory epithelia (CSE). CSE tissues were collected from rat inner ears 1d after the rats were exposed to a 120-dB (sound pressure level) noise for 2 h. The RNA-Seq generated over 176 million sequence reads for the normal CSE and over 164 million reads for the noise-traumatized CSE. Alignment of these sequences with the rat Rn4 genome revealed the expression of over 17,000 gene transcripts in the CSE, over 2000 of which were exclusively expressed in either the normal or noise-traumatized CSE. Seventy-eight gene transcripts were differentially expressed (70 upregulated and 8 downregulated) after acoustic trauma. Many of the differentially expressed genes are related to the innate immune system. Further expression analyses using quantitative real time PCR confirmed the constitutive expression of multiple complement genes in the normal organ of Corti and the changes in the expression levels of the complement factor I (Cfi) and complement component 1, s subcomponent (C1s) after acoustic trauma. Moreover, protein expression analysis revealed strong expression of Cfi and C1s proteins in the organ of Corti. Importantly, these proteins exhibited expression changes following acoustic trauma. Collectively, the results of the current investigation suggest the involvement of the complement components in cochlear responses to acoustic trauma.
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