Philippe Vincent, Ph.D.

Meet the Researcher

Vincent received his doctorate in cell biology and physiopathology from the University of Bordeaux, France. He is a postdoctoral fellow in the department of otolaryngology–head and neck surgery at Johns Hopkins School of Medicine in Baltimore. Vincent’s 2018 Emerging Research Grant was funded by Hearing Health Foundation, as directed by the Council of Scientific Trustees.

Sensory hair cells in the inner ear pick up the sound signal and transmit it to auditory nerve fibers through chemical synapses. They do this by releasing the transmitter glutamate; auditory nerve fibers then transmit the sound-coding signal to the brain. Sound intensity is encoded by the amount of glutamate released by the hair cell.

However, as a result of noise exposure, auditory nerve fiber endings can be damaged, most likely due to an excessive influx of calcium. This phenomenon is called excitotoxicity, but it is not completely understood. I will investigate the molecular mechanisms of synaptic transmissions between hair cells and auditory nerve fibers by testing how they are affected after noise trauma.

After reading several papers on noise-induced hearing loss and hair cell/nerve fiber regeneration, I saw many researchers are focused on how to restore hearing function. But I decided to work on finding tools to prevent nerve death from noise or aging through examining how calcium ions enter auditory nerve fibers.

I decided to become an electrophysiologist because I liked the challenge of the patch-clamp technique, especially when studying the organ of Corti. There the nerve fibers are extraordinarily small compared with neurons in the central nervous system.

I dedicated my Ph.D. thesis to my wife, a nurse, for her support. Three years of work resulted in four first-author publications and one co-authored paper. I’m proud that this research contributed to the knowledge of molecular mechanisms underlying synaptic transmissions between hair cells and spiral ganglion neurons, leading me now to examine the role of calcium ions in more detail. I believe hearing loss is an underestimated public health issue, so my ultimate goal is to develop protective therapies.

I enjoy making scale models. I can spend all day assembling and painting the different parts. Patience in both electrophysiology and making models is paramount. I just completed the Air France Airbus A380 (scale 1:125). Given its size (roughly two feet long and wide), assembling and painting were pretty challenging.

Philippe Vincent, Ph.D.’s grant was funded by Hearing Health Foundation, as directed by the Council of Scientific Trustees.

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The Research

Johns Hopkins University
Investigating mechanisms of degeneration of ribbon synapses between auditory inner hair cells and type 1 afferent nerve fibers after noise trauma in mammals

Sensory hair cells in the inner ear pick up the sound signal and transmit it to auditory nerve fibers through chemical synapses by releasing the transmitter glutamate; auditory nerve fibers then transmit the sound-coding signal to the brain. Sound intensity is encoded by the amount of glutamate released by the hair cell, leading to glutamate receptor activation and then action potential firing in auditory nerve fibers. During noise exposure, auditory nerve fiber endings can be damaged short- or long-term, most likely due to an excessive influx of calcium. This phenomenon is called excitotoxicity, but the underlying mechanisms are not completely understood. This project will investigate molecular mechanisms of synaptic transmission between hair cells and auditory nerve fibers and how they are affected after noise trauma.

Long-term goal: To understand the molecular mechanisms of synaptic transmission in the inner ear and the effects of noise exposure on this transmission process, in order to find methods to protect hair cell synaptic function and prevent hearing loss.