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Allen Ryan, PhD

Allen Ryan, PhD



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My laboratory studies the basic biology of hearing. A major focus of the group is the sensory hair cells of the cochlea. This includes studies of gene regulation in these cells, as well as fate determination by combinatorial transcription factor coding. We also study cellular mechanisms of hair cell damage and death induced by ototoxic drugs, noise trauma and excitotoxicity. A second area of interest is the two types of afferent neurons in the cochlea. In particular the type II neurons that innervate outer hair cells are poorly understood with respect to their function and the regulation of their complex pathfinding to their target hair cells. We also study pathogenesis and recovery of the middle ear mucosa during otitis media, with a focus on cell phenotype determination and innate immunity. Finally, we are interested in novel methods for drug delivery to the middle and inner ears.

Ryan AF. The cell cycle and the development and regeneration of hair cells. Curr Topics Devel Biol 57: 449-466, 2003.

Brors D, Bodmer D, Pak K, Aletsee C, Schafers M, Dazert S, Ryan AF. EphA4 provides repulsive signals to developing cochlear ganglion neuritis mediated through ephrin-B2 and –B3. J Comp Neurol 462: 90-100, 2003.

Zheng J, Long KB, Matsuda K, Madison LD, Ryan AF, Dallos P. Genomic characterization and expression of mouse prestin, the motor protein of outer hair cells. Mamm Genome 14: 87-96, 2003.

Skinner LJ, Enee V, Beurg M, Jung HH, Ryan AF, Hafidi A, Aran JM, Dulon D. Contribution of BK Ca2+-activated K+ channels to auditory neurotransmission in the guinea pig cochlea. J Neurophysiol 90:320-32, 2003.

Battaglia A, Bodmer D, Brors D, Pak K, Frangos JA, Ryan AF. Involvement of Ras activation in toxic hair cell damage of the mammalian cochlea. Neuroscience 122: 1025-1035, 2003.

Wittig JH, Ryan AF, Asbeck PM. A reusable microfluidic plate with alternate-choice architecture for assessing growth preference in tissue culture. J Neurosci Meth 144: 79-89, 2005.

Greenwood D, Jagger DJ, Huang LC, Hoya N, Thorne PR, Wildman SS, King BF, Pak K, Ryan AF, Housley GD. P2X receptor signaling inhibits BDNF-mediated spiral ganglion neuron development in the neonatal rat cochlea. Development 134:1407-141, 2007.

Schwander M, Sczaniecka A, Grillet N, Bailey JS, Avenarius M, Najmabadi H, Steffy BM, Federe GC, Lagler EA, Banan R, Hice R, Grabowski-Boase L, Keithley EM, Ryan AF, Housley GD, Wiltshire T, Smith RJ, Tarantino LM, Müller U. A forward genetics screen in mice identifies recessive deafness traits and reveals that pejvakin is essential for outer hair cell function. J Neurosci 27:2163-2175, 2007.

Hedlund M, Tangvoranuntakul P, Takematsu H, Long JM, Housley GD, Kozutsumi Y, Suzuki A, Wynshaw-Boris A, Ryan AF, Gallo RL, Varki N, Varki A. N-glycolylneuraminic acid deficiency in mice: Implications for human biology and evolution. Molec Cell Biol 27: 4340-4346, 2007.

Evans AR, Euteneuer S, Chavez E, Mullen LM, Hui EE, Bhatia SN, Ryan AF. Laminin and fibronectin modulate inner ear spiral ganglion neurite outgrowth in an in vitro alternate choice assay. Dev Neurobiol 67:1721-1730, 2007.

Tabuchi K, Pak K, Chavez E, Ryan AF. Role of inhibitor of apoptosis protein in gentamycin-induced hair cell damage. Neurosci 149:213-222, 2007.

Du X, Schwander M, Moresco EM, Viviani P, Haller C, Hildebrand MS, Pak K, Tarantino L, Roberts A, Richardson H, Koob G, Najmabadi H, Ryan AF, Smith RJH, Mueller U, Beutler B. A catechol-O-methyltransferase that is essential for auditory function in mice and humans. PNAS 105:14609-14614, 2008.

Choung YH, Taura A, Pak K, Choi S, Masuda M, Ryan AF. Generation of highly reactive oxygen species is closely related to hair cell damage in rat organ of Corti treated with gentamicin. Neurosci 161: 214-226, 2009.

Leichtle A, Hernandez M, Pak K, Webster NJ, Wasserman SI, Ryan AF. TRIF, a toll-like receptor adaptor, contributes to otitis media pathogenesis and recovery. BMC Immunol 10: 45-53, 2009.

Lai Y, Radeki K, Park HJ, Di Nardo A, Cogen A, Leichtle A, Cogen A, Wu ZR, Huang CM, Ryan AF, Gallo RL. Commensal bacteria regulate Toll-like receptor 3-dependent inflammation after skin injury. Nature Med 15:1377-1382, 2009.

Leichtle A, Hernandez M, Ebmeyer J, Yamasaki K, Lai Y, Radek K, Choung YH, Euteneuer S, Pak K, Gallo R, Wasserman SI, Ryan AF. CC chemokine lagand 3 overcomes the bacteriocidal and phagocytic defect of macrophages and hastens recovery from experimental otitis media in TNF-/- mice. J Immunol 184: 3087-3097, 2010.

Taura A, Taura K, Choung YH, Masuda M, Pak K, Eduardo Chavez E. Ryan AF. Histone deacetylase inhibition enhances adenoviral vector transduction in inner ear tissue. Neurosci 166:1185-1193, 2010.

Ebmeyer J, Leichtle A, Hernandez M, Umay Ebmeyer U, Jacob Husseman J, Pak K, Sudhoff S, David Broide D, Wasserman S, Ryan AF. TNF deletion alters apoptosis as well as caspase 3 and 4 expression during otitis media. BMC Immunol 12: 12, 2011.

Leichtle A, Hernandez M, Lee J, Pak K, Webster N, Wasserman SI, Ryan AF. The role of DNA sensing and the innate immune receptor TLR9 in otitis media. Innate Immun Jan 14, 2011 [Epub ahead of print].

Masuda M, Dulon D, Pak K, Mullen L, Li Y, Erkman L and Ryan AF. Regulation of the pou4f3 gene by 5’ DNA. Neuroscience. In revision, 2011.