Albert Edge, Ph.D.
Professor of Otology and Laryngology
Director, Tillotson Cell Biology Unit
Director of the Tillotson Cell Biology Unit, Dr. Albert Edge is an Associate Professor of Otology and Laryngology at Harvard Medical School based at Massachusetts Eye and Ear. He received his Ph.D. in biochemistry from Albany Medical College and was postdoctoral fellow in the Department of Biological Chemistry at Harvard Medical School. Dr. Edge’s research is focused on the mechanisms of cellular repair in the nervous system. Specifically, his laboratory works toward replacing both hair cells and first order cochlear neurons of the inner ear lost to a variety of causes, including genetically determined degenerative disorders, noise trauma and ototoxicity. Members of his laboratory are investigating endogenous stem cells in the cochlea that can generate hair cells and spiral ganglion neurons in damaged ears and is attempting to define the molecular pathways for the determination of cell fate from endogenous and embryonic stem cells.
The discovery of new pathways that influence the differentiation of inner ear stem cells creates a platform for development of drugs or other procedures to activate endogenous stem cells to replace hair cell or neurons. Dr. Edge and his laboratory staff have discovered cochlear progenitor cells that express Lgr5, a gene also found in the stem cells of the intestine. Wnt signaling stimulates proliferation of Lgr5-expressing cells and converts them into hair cells. They have also found that Notch signaling inhibits differentiation of hair cells and that inhibition of Notch after hair cell loss in the adult cochlea can induce hair cell regeneration and a partial recovery of hearing.
Dr. Edge also investigates the potential of neural progenitor cells to replace auditory neurons and has developed in vitro and in vivo systems for replacement of damaged cells in the inner ear. In vitro synaptogenesis assays in the laboratory allow screening of molecules that inhibit formation of synapses between the spiral ganglion neurons and hair cells. Inhibitory axon guidance molecules decrease fiber growth to hair cells, while glutamate and neurotrophins enhance new synapse formation. They have taken these findings into the living animal and have shown that neurons derived from stem cells innervate hair cells after direct implantation into ears with hearing loss due to nerve damage. Regeneration of auditory neurons and their connections to hair cells could be a treatment for hearing loss.
Generating mouse models of degenerative diseases using Cre/lox mediated in vivo mosaic cell ablation. Fujioka M, Tokano H, Fujioka KS, Okano H, Edge ASB. J Clin Invest 121:2462-2469, 2011.
Wnt responsive Lgr5-expressing stem cells are hair cell progenitors in the cochlea. Shi F, Kempfle J, Edge ASB. J Neurosci 32:9639-9648, 2012.
Notch inhibition induces cochlear hair cell regeneration and recovery of hearing
after acoustic trauma. Mizutari K, Fujioka M, Hosoya M, Bramhall N, Okano HJ, Okano H, Edge ASB. Neuron 77:58-69, 2013.
Hair cell generation by β-catenin overexpression in Lgr5-positive cochlear progenitors. Shi F, Hu L, Edge ASB. Proc Natl Acad Sci 110:13851-13856, 2013.
Lgr5-positive supporting cells generate new hair cells in the postnatal cochlea. Bramhall N, Shi F, Arnold K, Hochedlinger K, Edge ASB. Stem Cell Reports 2:311-322, 2014.