Research Overview
Hair Cell Regeneration in Avian and Mammalian Inner Ear
This research program focuses on hair cell regeneration in the inner ear of birds and mammals. Past research has shown that birds have the capacity to regenerate a nearly normal number and pattern of hair cells in the cochlea and vestibular epithelia after otologic trauma. These regenerated hair cells are functional, establish connections with the brain and restore behavioral losses. Mammals show very limited proliferation and no hair cell differentiation and remain hearing- or balance-impaired after similar trauma. This research program will attempt to better understand the biological mechanisms underlying this regeneration process in birds by intensive study of the hair cell progenitors and will further analyze the role of cell-cell interactions for initiation of mitotic activity in hair cell progenitors in avian and mammalian inner ear tissue.
Four approaches to these problems are the focus of this research. One set of experiments uses electron microscopic reconstructions of normal and regenerating sensory epithelium from the cochlea of chicks to examine the variations of sensory epithelium supporting cell morphology and ultrastructure in normal animals and as regeneration begins. A second set of experiments will attempt to isolate the hair cell progenitors from the avian cochlea by making culture systems enriched for mitotic cells and then isolating this population into a purified group of regenerative supporting cells. A third group of experiments examines the cell-surface receptors that may play a role either initiating or inhibiting mitotic activity in the inner ear sensory epithelium of birds and mammals. A forth set of studies examines the expression of cell cycle regulatory genes in the mammalian inner ear and examines the outcomes of manipulating these proteins.
Ontogeny of the Vertebrate Sensory Processes
