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Principal Investigator: Ksenia Gnedeva
Organization: UNIVERSITY OF SOUTHERN CALIFORNIA
Fiscal Year: 2024
Award: $461,786
Funding agency: National Institute on Deafness and Other Communication Disorders
Project Summary
The main way in which non-mammalian vertebrates, such as fish, restore sensory hair cells is through
proliferation and differentiation of the residual population of supporting cells. In contrast, supporting cells lose
the capacity to proliferate postnatally in mammals, and the molecular machinery preventing cell cycle reentry
remains poorly understood.
Our work has established that Hippo signaling serves as a major repressive mechanism that blocks
supporting cell proliferation and plasticity in the mammalian inner ear. In three Aims, we will identify the molecular
mechanism by which Hippo inhibition promotes mitotic sensory receptor regeneration in the adult utricle explants
(Aim 1); assess whether reversible pharmacologic inactivation of Hippo signaling stimulates bona fide vestibular
hair cell regeneration to support functional recovery in vivo (Aim 2); and assess the pathway’s interaction with
the cell cycle inhibitor p27Kip1, specific to the organ of Corti, in the adult inner ear in vivo (Aim 3). The long-term
goal of this proposal is to identify therapeutic strategies for hearing and balance restoration through controlled
manipulation of the Hippo pathway.
Due to its relatively recent discovery, study of the Hippo pathway in the inner ear is innovative in itself.
Furthermore, our group has pioneered this field and developed several specialized research tools to aid the
study of the pathway in the inner ear. Most notably, we identified the first small-molecule inhibitor of Lats kinases
– the core enzymes in Hippo signaling – that we show to potently induce supporting cell proliferation and the
initial stages of hair cell regeneration in vitro and in vivo. We also optimized posterior semicircular canal approach
for LKI delivery into the inner ear and utilize several cutting-edge genetic and epigenetic techniques (e.g
multiome sequencing, CUT&RUN).
The proposed basic research is significant because understanding the molecular machinery blocking cell
cycle reentry in the inner ear may determine new therapeutic targets for induction of hair cell regeneration.
Remarkably, we demonstrate that brief pharmacologic inhibition of Lats kinases induces supporting cell
proliferation in the adult utricle, allowing progeny to re-exit the cell cycle and spontaneously upregulate sensory
receptor genes upon drug withdrawal. Collectively our data show that temporal inactivation of Hippo signaling is
sufficient to promote the initial stages of hair cell regeneration through supporting cell division – a process thought
to be permanently suppressed in the adult mammalian inner ear.
Terms: <21+ years old><ATAC><Ablation><Address><Adult><Adult Human><Auditory><Auditory Brainstem Responses><Basic Research><Basic Science><Binding><CDK Inhibitor Protein><CDK inhibitor p27><CDKI Protein><CDKN1B protein><CDKN4 protein><CUT&RUN><Cell Body><Cell Communication and Signaling><Cell Cycle><Cell Cycle Progression><Cell Division Cycle><Cell Growth in Number><Cell Maturation><Cell Multiplication><Cell Proliferation><Cell Signaling><Cell division><Cells><Cellular Proliferation><Chromatin><Cleavage Targets and Release Using Nuclease><Cleavage Under Targets and Release Using Nuclease><Cochlea><Cochlear Organ><Coloring Agents><Corti Cell><Cortis Organ><Corynebacterium Diphtheriae Toxin><Cyclin Kinase Inhibitor><Cyclin-Dependent Kinase Inhibitor><Cyclin-Dependent Kinase Inhibitor p27><Data><Deterioration><Diphtheria Toxin><Drugs><Dyes><Ear><Embryo><Embryonic><Enzyme Gene><Enzymes><Epigenetic><Epigenetic Change><Epigenetic Mechanism><Epigenetic Process><Equilibrium><Equilibrium Hair Cell><Evoked Potentials><Fishes><Gene Activation><Gene Expression><Gene Transcription><Generalized Growth><Genes><Genetic><Genetic Transcription><Goals><Growth><Hair><Hair Cells><Health><Hearing><Immunohistochemistry><Immunohistochemistry Cell/Tissue><Immunohistochemistry Staining Method><In Vitro><Injections><Injury><Internal Ear><Intracellular Communication and Signaling><Kinases><Kip1 protein><Knowledge><LPTN><Label><Labyrinth><Link><Mammalia><Mammals><Measurement><Measures><Mediating><Medication><Methods><Mice><Mice Mammals><Mission><Mitotic><Molecular><Molecular Analysis><Molecular Interaction><Monitor><Murine><Mus><NIH><National Institutes of Health><Natural regeneration><Neonatal><Neural Receptors><Neuroreceptors><Non-Polyadenylated RNA><Organ><Organ of Corti><Pathway interactions><Pharmaceutical Preparations><Phenotype><Phosphotransferase Gene><Phosphotransferases><Population><Posterior Semicircular Canal><Process><Progenitor Cells><Proliferating><RNA><RNA Expression><RNA Gene Products><Receptor Gene><Recovery><Recovery of Function><Regeneration><Regimen><Repression><Research><Residual><Residual state><Resistance><Ribonucleic Acid><SCM-1><SCM-1a><SCM1><SCYC1><Scanning Electron Microscopy><Sensory><Sensory Hair><Sensory Receptors><Signal Transduction><Signal Transduction Systems><Signaling><Spiral Organ><Spiral Organ of Corti><Structure of posterior semicircular canal><Supporting Cell><Techniques><Testing><Therapeutic><Time><Tissue Growth><Transcription><Transcription Activator><Transcription Coactivator><Transcription Factor Coactivator><Transcriptional Activator><Transcriptional Activator/Coactivator><Transcriptional Coactivator><Transphosphorylases><United States National Institutes of Health><Utricle structure><Utricles><Vertebrate Animals><Vertebrates><Vestibular><Vestibular Hair Cells><Vestibular System Function><Vestibular function><Work><XCL1><XCL1 gene><adulthood><balance><balance function><biological signal transduction><cyclin-dependent kinase inhibitor 1B><drug withdrawal><drug/agent><ear hair cell><epigenetically><experiment><experimental research><experimental study><experiments><functional recovery><hair cell regeneration><in vitro regeneration><in vivo><in vivo regeneration><inhibitor><injuries><inner ear><innovate><innovation><innovative><multiomics><multiple omics><new drug target><new druggable target><new pharmacotherapy target><new therapeutic target><new therapy target><novel drug target><novel druggable target><novel pharmacotherapy target><novel therapeutic target><novel therapy target><ontogeny><p27 Kip1 protein><p27 protein><p27-Kip1><p27Kip1 protein><panomics><pathway><pharmacologic><postmitotic><postnatal><prevent><preventing><progenitor><regenerate><resistant><restoration><small molecular inhibitor><small molecule inhibitor><stem cells><synergism><tool><transcription co-activator><transcriptional co-activator><uptake><vertebrata><vestibular system>