Creighton University
Grant: $207,850 - National Institutes of Health - Jun. 2, 2009
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Award Description: The senses of hearing and balance depend upon hair cells, the sensory receptors of the inner ear. Hair cells transduce mechanical stimuli into electrical activity. Loss of hair cells or damage to the transduction apparatus, the stereocilium bundle on the surface of the hair cell, as a result of aging or exposure to noise and ototoxic drugs, is the major cause of noncongenital hearing and balance deficits. Studies in the last two decades have demonstrated that lost hair cells can be replaced by production of new hair cells in birds and lower vertebrates. Hair cell regeneration is limited in mammals, but there is evidence to suggest that damaged hair cells may survive and undergo intracellular repair. In this proposal, we will determine whether mammalian cochlear hair cells could survive after loss of stereocilia. We will simulate the acoustic trauma-induced stereociliary loss by ablating the hair bundles in the culture preparation. If the hair cells can survive for some time, this window of opportunity can be crucial for genetic or chemical therapeutic interventions in order to repair hair bundles. Thus, we will explore the feasibility of regenerating stereocilia using a gene therapy approach. We have two specific aims for this Exploratory/Developmental research. In Aim 1, we will examine the fate of mammalian hair cells after their stereocilia have been intentionally removed to determine whether hair cells can survive and develop. In Aim 2, we will determine whether over-expression of myosin-15a and whirlin, two genes that are involved in stereocilium morphogenesis, can promote hair-bundle repair/regeneration and whether the newly regenerated stereocilia are functional. The experiments will be carried out in the cultured organ of Corti from neonatal gerbils. The hair bundles of outer hair cells in a designated area of the organ of Corti will be removed by a small suction pipette. Hair-cell survival/development and stereocilium morphology/function will be examined using immunohistochemistry (with confocal microscopy), time-lapse imaging, scanning electron microscopy, and electrophysiology. This project is highly significant, since exploring the strategies of maintaining, rescuing, and repairing injured hair cells are essential to the biological remediation and prevention of hair cell-related hearing loss and deafness.?????
Project Description: We have made significant progress. The overall goal of this project is to explore whether cochlear hair cells are able to regenerate their lost stereocilia using the gene therapy. We propose to use a tissue culture model for this study. We simulate noise-induced hair bundle loss by removing the stereocilia using a suction pipette. We have demonstrated that hair cells are not able to spontaneously repair their lost bundles. However, the bundleless hair cells can survive the bundle loss for up to 13 days. A manuscript on this has been submitted. Our next step is to introduce two genes to the hair cells to see whether overexpression of those two genes can induce regeneration of the hair bundles.
Jobs Summary: There is a job opening for someone with a PhD in neuroscience. Several potential candidates have been interviewed. A PhD at Washington University will be hired beginning from November 1, 2009. Another person in the lab is also retained. That is a technician position with MS degree. (Total jobs reported: 2)
Project Status: Less Than 50% Completed
This award's data was last updated on Jun. 2, 2009. Help expand these official descriptions using the wiki below.
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