Expression data of miRNA from mice cochlea during aging
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ABSTRACT: To identify which miRNAs are involved in the onset and progression of age-related hearing loss in the mammalian cochlea We used miRNA microarrays to screen the miRNAs which exhibit the drastic changes in their expressing level during the aging of the cochlea The organ of Corti (OC), the major pathological sites of presbycusis in cochlea, was collected separately at 3 timepoints during the life span. Two strains were selected: C57bl/6j (as accelerated prebycusis model) and CBA/J (as naturally occured presbycusis model). The selected timepoints were: Postnatal 21 days (P21), 3 month (3m) and 9 month (9m) for C57 mice, and P21, 9m, 16m for CBA mice.
Project description:Spiral ganglion neurons (SGNs) and the associated components of the auditory nerve are primary carriers of auditory information from hair cells to the brain. Loss of SGNs occurs with many pathological conditions, resulting in permanent sensorineural hearing loss. Neural stem/progenitors (NSPs) have been well-characterized in several locations of adult brain and retina. However, it is unclear whether NSPs are present in the adult auditory nerve. Here we examined the self-renewal potential of the adult auditory nerve using ouabain application as a well-established mouse model of acute SGN injury. The observed increase in cell proliferation, alteration in enchromatin/heterochromatin ratio and down-regulation of histone deacetylase expression in glial cells suggest that the quiescent glial cells convert to an activated state after SGN degeneration. This was further confirmed by global gene expression analysis of injured auditory nerves, which showed up-regulation of numerous neurogenesis- and/or development-associated genes shortly after ouabain exposure. These genes include molecular markers commonly used for the identification of NSPs. Under a strict culture regimen, auditory nerve-derived cells of adult mouse ears gave rise to neurospheres, suggesting that multipotent NSPs are present in adult cochlear nerve. Neurosphere assays on Sox2 transgenic mice revealed that Sox2+ glial cells are the source for NSPs. Our data also showed that acute injury or hypoxia enhances neurosphere formation. Taken together, our study revealed that glial cells of adult cochlea exhibit several NSP characteristics, and hence these mature non-neuronal cells may be important targets for promoting self-repair of degenerative auditory nerves. Analysis was conducted on auditory nerve samples from stages encompassing maturation and onset of hearing. Cochleas were collected from euthanized mice (CBA/CaJ) at perinatal (P) stages P0, P3, P7, P10, P14 and P21. Cochleas underwent microdissection to remove the outer bony cochlear shell and cochlear lateral wall, thus preserving the modiolus portion of cochlea which contains mainly the auditory nerve. Paired cochleas (i.e., from left and right ears) from each mouse were pooled to make individual samples. All sample types were done in experimental duplicate (n=2).
Project description:Various organ failure induced by chronic intake of GeO2 is one of the well known disease related to mitochondrial dysfunction. The 0.15% GeO2 treated CBA mice shows severe hearing loss in 4M. Here we analyzed cochlear gene expression of 6 months old CBA mice using microarrays treated with normal chow or that containing 0.15% GeO2 for four months. Auditory brainstem response (ABR) analysis confirmed that severe age-related hearing loss occured in GeO2 treated mice, whereas no hearing loss occured in normal chow treated mice. Comprehensive gene expression analysis identified genes correlated with GeO2-induced mithochodrial dysfunction genes and revealed that 28 genes encoding components of the mitochondrial respiratory chain were significantly down-regulated. These observations provide evidence that GeO2-induced hearing loss is associated with the down-regulation of genes involved in the mitochondrial respiratory chain complexes in the cochlea of CBA mice. To determine the effects of GeO2, each control sample (n=5) was compared to each GeO2-intoxicated (n=5), generating a total of 25 pairwise comparisons. Using DAVIS and EASE, the identified genes were assign to GO: Biological Process categories of Gene Ontology Consortium. Furthermore, we used EASE to determine the total number of genes that were assigned to each biological process category, and to perform Fisher exact test. Quality control measures were not used. No replicates were done. Dye swap was not used.
Project description:High-flow causes the remodeling of arteries, in which smooth muscle cells play an important role. To know the profile of smooth muscle gene expression under high-flow conditions in vivo, flow of rabbit basilar artery was increased by ligation of both common carotid arteries. Microarrays were performed to profile the gene expression of smooth muscle cells isolated from rabbit basilar artery. Expression profiles indicate 43603 differentially expressed genes in smooth muscle cells exposed to high-flow insult compared with the sham control, of which 1470 genes were upregulated and 780 genes downregulated using 2 fold-changes and P<0.05 as a cut-off. Bilateral common carotid arteries of female New Zealand White rabbits were ligated to increase vascular flow.The control group was performed the same procedure to expose the CCAs without ligation. Rabbits were euthanized at day 5 after ligation or exposure of bilateral CCAs in both groups (n=3 for each group). The rabbits used and all procedures in this study were approved by the local Institutional Animal Care and Use Committee. Smooth muscle cells were isolated. After euthanization of rabbits, the whole basilar arteries were removed. The arteries were cleaned in PBS buffer,cannulated and perfused at a constant flow with a cocktail which contains PBS and 0.4 mg/ml elastase (Sigma) and 1 mg/ml collagenase (type 1A, Sigma). After an incubation time of 45 min, the tissue left was removed and stored in PBS. SMCs were released from the artery by trituration. Then Total RNA was extracted and gene chip tests were performed.
Project description:In order to gain insight into the molecular events which underlie auditory hair cell regeneration in chicken, we compared gene expression in chicken basilar papillae after 24, 48, and 72 hours in culture with or without forskolin (100uM).<br><br>Under sterile conditions, cochlear ducts containing the basilar papillae were carefully dissected out of ~4-day-old chicks and then individually cultured in DMEM with 10% fetal bovine serum with or without forskolin (final concentration 100 ?M, delivered in 1% DMSO) for either 24, 48, or 72 hours at 37ï¾°C. Control samples received DMSO at 1% as a vehicle control. At the end of 3 days, the tegmentum vasculosum was dissected off to expose the auditory epithelium, which was delicately freed from the underlying cartilaginous plates. All explants were kept in culture for 3 days because new hair cells are first seen in basilar papillae treated with forskolin after ~3 days of exposure to the drug [19]. Therefore, at even earlier time points in culture the molecular events that subserve hair cell proliferation are well underway. Each sample was comprised of 3 auditory epithelia from 3 different chicks which were put in ~100 ?L of DMEM and then immediately frozen at -80ï¾°C until RNA isolation could be performed. There were a total of 24 samples in this experiment: six 72-hour forskolin, six 72-hour control, three 48-hour forskolin, three 48-hour control, three 24-hour forskolin, and three 24-hour control.
Project description:Age-related hearing loss (ARHL) is a progressive sensorineural hearing loss that occurs as people get older. As many as 35% to 50% of the population aged between 65 and 75 have ARHL. Although age-related changes in the central auditory system can contribute to hearing impairment, degeneration of the mechanosensitive hair cells in the cochlea is the prevalent cause of ARHL. The molecular mechanisms of hair cell aging are largely unknown. To provide a comprehensive dataset of age-related genes and pathways in hair cells, we individually collected inner and outer hair cells, the two types of sensory receptor cells in the cochlea, from 9- and 26-month-old CBA/J mice and performed cell type-specific transcriptomic analysis. Our analysis showed a significant reduction of the expression of genes related to hair cell structure and function such as Tmc1, Kcnq4, Kcnj13, Slc7a14, Slc17a8, Chrna9/Chrna10, and Slc26a5. Our hair cell-specific transcriptome analysis provides a rich resource for mechanistic studies of biological aging of cochlear hair cells.
Project description:Whole body knockout mice lacking IQ-motif containing GTPase-activating protein 2 (IQGAP2) develop spontaneous hepatocellular carcinoma (HCC) at the age of 12 months and older (Schmidt et al., 2008). Hepatic transcript expression profiles were obtained for IQGAP2 knockout and wild-type control mice of two age groups, 6- and 24-month-old. Liver samples from 24-month-old IQGAP2 knockout mice were HCC tumors, livers from all other groups were tumor-free. Results provide insights into the potential role of IQGAP2 as a liver-specific tumor suppressor. Transcript profiles of four groups of mouse livers (N = 3 in each group) were compared using Affymetrix GeneChip® Mouse Genome 430 2.0 Array. The groups included livers from 6- and 24-month-old wild-type (WT) mice and 6- and 24-month-old (KO) Iqgap2-/- mice.
Project description:Spiral ganglion neurons (SGNs) and the associated components of the auditory nerve are primary carriers of auditory information from hair cells to the brain. Loss of SGNs occurs with many pathological conditions, resulting in permanent sensorineural hearing loss. Neural stem/progenitors (NSPs) have been well-characterized in several locations of adult brain and retina. However, it is unclear whether NSPs are present in the adult auditory nerve. Here we examined the self-renewal potential of the adult auditory nerve using ouabain application as a well-established mouse model of acute SGN injury. The observed increase in cell proliferation, alteration in enchromatin/heterochromatin ratio and down-regulation of histone deacetylase expression in glial cells suggest that the quiescent glial cells convert to an activated state after SGN degeneration. This was further confirmed by global gene expression analysis of injured auditory nerves, which showed up-regulation of numerous neurogenesis- and/or development-associated genes shortly after ouabain exposure. These genes include molecular markers commonly used for the identification of NSPs. Under a strict culture regimen, auditory nerve-derived cells of adult mouse ears gave rise to neurospheres, suggesting that multipotent NSPs are present in adult cochlear nerve. Neurosphere assays on Sox2 transgenic mice revealed that Sox2+ glial cells are the source for NSPs. Our data also showed that acute injury or hypoxia enhances neurosphere formation. Taken together, our study revealed that glial cells of adult cochlea exhibit several NSP characteristics, and hence these mature non-neuronal cells may be important targets for promoting self-repair of degenerative auditory nerves. Adult Mice (CBA/CaJ, aged 8 to 12 weeks) were anesthetized and subjected to survival surgery to expose the bulla of the right ear. A ouabain solution (3 mM, approximately 10 ul) was administered in the round window niche. This solution was wicked away and replaced with fresh ouabain approximately every 10 min during a cummulative exposure period of 60 min. The left ears (i.e., contralateral) were not surgically manipulated and were used as controls. Mice were maintained for 3 days or 7 days following treatments, then euthanized, and the oubain-treated and contralateral cochleas were removed. Cochleas underwent microdissection to remove the outer bony cochlear shell and cochlear lateral wall, thus preserving the modiolus portion of cochlea which contains mainly the auditory nerve. All sample types were prepared in experimental triplicate (n=3).
Project description:Various organ failure induced by chronic intake of GeO2 is one of the well known disease related to mitochondrial dysfunction. The 0.15% GeO2 treated CBA mice shows severe hearing loss in 4M. Here we analyzed cochlear gene expression of 6 months old CBA mice using microarrays treated with normal chow or that containing 0.15% GeO2 for four months. Auditory brainstem response (ABR) analysis confirmed that severe age-related hearing loss occured in GeO2 treated mice, whereas no hearing loss occured in normal chow treated mice. Comprehensive gene expression analysis identified genes correlated with GeO2-induced mithochodrial dysfunction genes and revealed that 28 genes encoding components of the mitochondrial respiratory chain were significantly down-regulated. These observations provide evidence that GeO2-induced hearing loss is associated with the down-regulation of genes involved in the mitochondrial respiratory chain complexes in the cochlea of CBA mice.
Project description:Smoking is one of the major modifiable risk factors in the development and progression of chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD). Modified-risk tobacco products (MRTP) are being developed to provide substitute products for smokers who are unable or unwilling to quit, to lessen the smoking-related health risks. In this study, the ApoE-/- mouse model was used to investigate the impact of cigarette smoke (CS) from the reference cigarette 3R4F, or aerosol from two potential MRTPs based on the heat-not-burn principle, carbon-heated tobacco product 1.2 (CHTP 1.2) and tobacco heating system 2.2 (THS 2.2), on the cardiovascular and respiratory system over a 6-month period. In addition to chronic exposure, cessation or switching to CHTP1.2 after 3 months of CS exposure was assessed. A systems toxicology approach combining physiology, histology and molecular measurements (transcriptomics and proteomics) was used to evaluate the impact of MRTP aerosols in comparison to CS. The current data represent the lung transcriptomics analysis. Note that the animal identifier (CAN) can be used for sample matching across different sample types and data modalities.