Project description:We designed an ex vivo system to culture tissue explants from lymphoma tissue. To determine if the explants derived from vavP-Bcl2 mouse spleens retained the cellular composition and transcriptional profile of the cells in the original tissue, we analyzed six lymphomoids derived from the spleens of two mice, after one or two weeks in culture, and the original spleen tissues by single-cell RNA-sequencing.
Project description:We evaluated the effects of pioglitazone in mouse organ of Corti (OC) explants to characterize its influence on signaling pathways involved in auditory hair cell damage. Organ of Corti explants were cultured with pioglitazone, gentamicin, or a combination of both agents. Pioglitazone treatment resulted in a significant repression of interferon (IFN)-alpha and -gamma pathways and downstream cytokines, as assessed by RNA sequencing and quantitative PCR gene expression assays. More detailed investigation at the single gene and protein level showed that pioglitazone mediated its anti-inflammatory effects through alterations of the Toll-like receptor (TLR) and STAT pathways. Together, these results indicate that pioglitazone significantly represses IFN and TLR in the cochlea, dampening the activity of gentamicin-induced pathways. These data support our previous results demonstrating significant protection of auditory hair cells in organ of Corti explants exposed to pioglitazone and other PPAR-targeted agents.
Project description:In the mammalian auditory system, frequency discrimination depends on numerous morphological and physiological properties of the organ of Corti that gradually change along the longitudinal (tonotopic) axis of the organ. For example, the basilar membrane stiffness changes tonotopically, thus affecting the tuning properties of individual hair cells. At the molecular level, those frequency-specific characteristics are mirrored by gene expression gradients; however, the molecular mechanisms controlling tonotopic gene expression in the mouse cochlea remain elusive. Through analyzing scRNA-seq data from two developmental time points, we predicted that morphogens, rather than a timing-associated mechanism, confer spatial identity in the cochlea. Subsequently, we reconstructed the developing cochlea in 3D space from scRNA-seq data to investigate the molecular pathways mediating tonotopic information. The retinoic acid and sonic hedgehog pathways were found to form opposing tonotopic gradients, and functional interrogation using mouse cochlear explants suggested that both pathways jointly specify the tonotopic axis during development.
Project description:Strategies to overcome irreversible cochlear hair cell (HC) damage and loss are of vital importance to develop a treatment for hearing loss. HC regeneration in adult cochlea relies on a two-phase process: 1) Reprogramming mature cochlear (SCs) to regain the properties of their younger selves; 2) Activating Atoh1, a gene responsible for HC fate-determining, in the reprogrammed adult SCs for HC regeneration. We have shown that, by transient co-activation of Myc and NICD (Notch1 intracellular domain), the adult mouse cochlea can be successfully reprogrammed to a relatively younger stage and regain progenitor capacity, with the regeneration of HCs following Atoh1 overexpression in vitro and in vivo. To identify molecules to reprogram mature cochlear SCs and HC regeneration, we utilized single-cell RNA sequencing and uncovered the pathways and their target genes underlying MYC/NICD-mediated reprogramming. We used an in-house adult cochlea explant culture system and carried out single-cell RNA sequencing to examine the gene expression profiles of cochlear explants from a transgenic mouse model, rtTa/tet-Myc/-tet-NICD, in response to Dox-induced MYC/NICD co-activation. We compared gene expression profiles between Atoh1 activation vs. MYC/NICD/Atoh1 co-activation.
Project description:DDA analysis of samples of commercial tryptic peptides of BSA which had been either untreated ("original"), conjugated with the Harnimarta et al sequencing reagent ("conj") or conjugated and exposed to alkaline cleavage conditions ("seq"). Data was searched in Proteome Discoverer 2.5 using a 58.017 Da for the sequencing reagent dynamic modification. The associated BSA2 fasta includes a synthetic sequence to generate in silico tryptic peptides representing the original BSA tryptic peptides lacking a single N-terminal amino acid.
Project description:Strategies to overcome irreversible cochlear hair cell (HC) damage and loss are of vital importance to develop a treatment for hearing loss. HC regeneration in adult cochlea relies on a two-phase process: 1) Reprogramming mature cochlear (SCs) to regain the properties of their younger selves; 2) Activating Atoh1, a gene responsible for HC fate-determining, in the reprogrammed adult SCs for HC regeneration. We have shown that, by transient co-activation of Myc and NICD (Notch1 intracellular domain), the adult mouse cochlea can be successfully reprogrammed to a relatively younger stage and regain progenitor capacity, with the regeneration of HCs following Atoh1 overexpression in vitro and in vivo. We identified a combination (the cocktail) of drug-like molecules composing of small molecules and siRNAs to activate the pathways of Myc, Notch1, Wnt and cAMP. To identify molecules to reprogram mature cochlear SCs and HC regeneration, we utilized single-cell RNA sequencing and uncovered the pathways and their target genes underlying chemical-mediated reprogramming. We used an in-house adult cochlea explant culture system and carried out single-cell RNA sequencing to examine the gene expression profiles of cochlear explants, in response to chemical-induced reprogramming. We compared gene expression profiles between Vehicle/ad.Atoh1 activation vs. Cocktail (chemical reprogramming)/ad.Atoh1 activation.
Project description:Strategies to overcome irreversible cochlear hair cell (HC) damage and loss are of vital importance to develop a treatment for hearing loss. HC regeneration in adult cochlea relies on a two-phase process: 1) Reprogramming mature cochlear (SCs) to regain the properties of their younger selves; 2) Activating Atoh1, a gene responsible for HC fate-determining, in the reprogrammed adult SCs for HC regeneration. We have shown that, by transient co-activation of Myc and NICD (Notch1 intracellular domain), the adult mouse cochlea can be successfully reprogrammed to a relatively younger stage and regain progenitor capacity, with the regeneration of HCs following Atoh1 overexpression in vitro and in vivo. To identify molecules to reprogram mature cochlear SCs, we utilized single-cell RNA sequencing and uncovered the pathways and their target genes underlying MYC/NICD-mediated reprogramming. We used an in-house adult cochlea explant culture system and carried out single-cell RNA sequencing to examine the gene expression profiles of cochlear explants from a transgenic mouse model, rtTa/tet-Myc/-tet-NICD, in response to Dox-induced MYC/NICD co-activation. We have shown that a 4-day treatment by Dox in cultured adult rtTa/tetMyc/-tet-NICD cochleae was sufficient to reprogram adult SCs for HC regeneration.
Project description:Hair cells undergo postnatal development that leads to formation of their sensory organelles, synaptic machinery, and in the case of cochlear outer hair cells, their electromotile mechanism. To examine the proteome changes over development, we isolated pools of 5000 Pou4f3-Gfp positive or negative cells from the cochlea or utricles; these cell pools were analyzed by data-dependent and data-independent acquisition (DDA and DIA) mass spectrometry. DDA data were used to generate spectral libraries, which enabled identification and accurate quantitation of specific proteins using the DIA datasets. We also isolated and pooled individual inner and outer hair cells from adult cochlea and compared their proteomes to those of developing hair cells. The DDA and DIA datasets will be valuable for accurately quantifying proteins in hair cells and non-hair cells over this developmental window.