Jeffrey R. Holt, Ph.D., Professor

I earned my doctorate from the Department of Physiology at the University of Rochester in 1995.  For my thesis work I studied inward rectifier potassium currents in saccular hair cells in Ruth Anne Eatock's lab.  I went on to a post-doctoral position in the Neurobiology Department at Harvard Medical School, where I characterized transduction and adaptation in vestibular hair cells and developed a viral vector system to DNA into sensory hair cells.  My first faculty position was at the University of Virginia.  In 2011 the lab moved to Boston Children’s Hospital / Harvard Medical School. I am currently a Professor in the Departments of Otolaryngology and Neurology in the F.M. Kirby Neurobiology Center where I am involved with graduate and medical student teaching; I am a member of the Harvard Medical School, Program in Neuroscience and the Program in Speech and Hearing Bioscience and Technology and the Biophysics Program.  As one of two principle investigators for the lab, I write grants and manuscripts for publication, supervise and mentor lab members and make time to work on my own research project.  I am currently working on several projects:  1) I am investigating the function of TMC genes in hair cells using viral vectors to deliver wild-type and mutant channel genes and 2) I am interested in identifying other genes and proteins required for hair cell mechanosensory transduction, and 3) I am working to develop inner ear gene therapy for patients with genetic hearing loss. 

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Hobbies:  Working late, playing with my kids, sailing, kite surfing, red wine, soccer, astrophotography 

 

jeffrey.holt-AT-childrens.harvard.edu                                            Jeff's CV:

 

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Gwenaelle S. Géléoc, Ph.D., Associate Professor

I am originally from France and moved to the United States in 1999.  My passion for inner ear research began as an undergraduate student at the University of Montpellier (France) when I first saw a sensory hair cell under the microscope. I have been fortunate to train with wonderful scientists including Corne Kros (Sussex University, UK), Guy Richardson (Sussex University, UK) and Jonathan Ashmore (UCL, UK). During my graduate work I developed a preparation which allowed me to record the first mechanotransduction currents from vestibular hair cells of the mammalian inner ear (Géléoc et al. 1996, 1997).  I realized that there was much to be learned by analyzing the pattern of functional developmental of inner ear hair cells. A prerequisite for understanding vestibular and auditory disorders is knowledge of how hair cells develop. Hair cells of the inner ear have the critical role of converting sound and head movement information into electrical signals which are transmitted to the brain.  Precisely how and when hair cells acquire mechanosensitivity is a major focus of my ongoing research. As an Associate Professor at Boston Children’s Hospital, I study molecules involved in the development and function of sensory hair cells and aim to develop new therapies for the treatment of deafness and balance, with a particular focus on Usher syndrome. My major contribution to the field of Usher syndrome research involved pioneering work demonstrating unprecedented recovery of auditory and balance function in an animal model of USH1C using gene replacement therapy with adeno-associated viral vectors (Pan et al. 2017). My team currently pursues research focused on USH1C, USH2A and USH3A.  My work is supported by the NIH, the Usher syndrome Society and others.                           

                                                                                                                                                Gwen's CV:

Hobbies: Doing artwork, running, cooking (and eating), sailing and hiking

            

gwenaelle.geleoc-AT-childrens.harvard.edu

 

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Stephanie Mauriac, Ph.D., Post-Doctoral Fellow

I grew up in Bordeaux, France. In 2015, I received my undergraduate degree from the University of Bordeaux in cellular biology and physiopathology. My interest for the inner ear began when I join the lab of Dr. Mireille Montcouquiol and Dr. Nathalie Sans in Bordeaux as a PhD student.  During my PhD, I studied a very rare pathology, called the Chudley McCullough Syndrome, characterized by early onset sensorineural deafness and brain anomalies. During this project, I learned different technics including biochemistry, Immunocytochemistry, surgery and dissection that permit us to clarify the etiology and identify a new molecular basis of this pathology. During this exciting project, I realized how this work is essential to find a treatment for these patients in order to improve their lives. After receiving my PhD degree in June, 2019, I had the great opportunity to join the lab of Dr. Jeffrey Holt and Dr. Gwenaelle Geleoc in October 2019 to continue in hearing research. My goal is to discover and develop approaches to restore auditory function by gene therapy in models of human deafness.

 

Hobbies : traveling, cooking, sewing, reading, music, movies

 

stephanie.mauriac-AT-childrens.harvard.edu

 

Yunqing Zhou, Ph.D., Post-Doctoral Fellow

I was born and raised in Shandong Province, China. Since middle school, I discovered my passion for biology and dreamed of making it my career. Therefore, I earned my Bachelor’s degree in Applied Biology from Hong Kong Baptist University in 2017 and then pursued a Ph.D. in Molecular, Cellular, and Integrative Biosciences at Pennsylvania State University. During my Ph.D., I was co-advised by Dr. Sarah Assmann, a molecular plant biologist, and Dr. Tim Jegla, a neuroscientist, to study the structure, function, and regulation of ion channels. Using interdisciplinary approaches, I investigated how plant ion channels are modulated by protons, divalent cations, and interacting proteins like heterotrimeric G proteins. While my Ph.D. projects mainly focused on voltage-gated potassium channels, I became fascinated by the beauty and complexity of mechanosensitive channels after learning about breakthroughs in Piezo and TMC channel studies. After completing my Ph.D. in 2024, I was very fortunate to join the Holt/Géléoc Lab, where I am deeply excited to explore the biophysical properties and regulatory mechanisms of mechanosensitive channels in inner ear hair cells and translate insights about ion channels into potential therapeutic strategies for treating hearing loss. 

 

Hobby: Cooking, exercising, mystery movies and novels, basketball of San Antonio Spurs

 

Yunqing.Zhou-AT-childrens.harvard.edu

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Evan Ratzan, Ph.D., Post-Doctoral Fellow

I grew up in the Rocky Mountains of Colorado but headed east to Amherst, MA where I obtained my Bachelor's degree in Cognitive Neuroscience from Hampshire College in 2009. My passion for neuroscience propelled me through a dual-degree program at the University of Utah where I received a Master's in Clinical Investigations and Ph.D. in Neuroscience. I worked in the lab of Dr. Michael R. Deans examining mechanisms of cell polarity acquisition in the developing vestibular system. This work lead to the interesting discovery that Fgf8 expression is a specific and perhaps the earliest marker of Type-I vestibular hair cell identity thus far identified. My graduate work also identified important factors downstream from Emx2  which contribute to regional specification within the developing vestibular maculae. My graduate experience included a variety of molecular biology techniques including RNAseq, FISH, mouse genetics, immunohistochemistry, and more which I was excited to apply to scientific questions with a clinically relevant focus. I was fortunate to join the Holt/Géléoc lab where I focus on molecular mechanisms of vestibular and auditory pathophysiology.

 

Hobbies: Rock and ice climbing, snowboarding, music, drawing, painting, and reading

 

evan.ratzan-AT-childrens.harvard.edu

 

Thibault Peineau, Ph.D., Post-Doctoral Fellow

I was born and raised in Tours, a charming city of the Loire Valley in France. In 2016, I graduated with a biology degree from Rennes. Then I went to Bordeaux for a Neuroscience Master’s degree. I had the opportunity to do my internship in the lab of Dr Didier DULON where I discovered the world of the Hearing research. During this internship I learned ABR (Auditory Brainstem Responses) and Patch Clamp techniques.  I was so passionate about this internship that I followed with a PhD. During my PhD, among others things, I used my training to characterize the molecular and physiological changes of ribbon synapses in inner hair cells during aging (Peineau et al. 2021). Working on old mice (1 year-old) contributed to improve my skills including the patch clamp technique. Moreover, I learned a lot of different techniques such as Intracochlear Injection, Live Calcium Imaging, Immunochemistry, Recording of Mechanotransduction.  In September 2022, I had the opportunity to join the Holt/Géléoc Lab to continue working in hearing research and learning the secrets of the cochlea.  My goal is to characterize the electrophysiological changes in deaf mice.  

 

Hobbies: Cooking, movies, gym, soccer, formula1 and learning new things.

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thibault.peineau-AT-childrens.harvard.edu

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​Tais Castagnola, Ph.D., Post-Doctoral Fellow

I was born in Bahia Blanca, a small town in Argentina. For as long as I can remember I was always eager to understand how even the simplest things work. Driven by that curiosity I decided to study Biology at the University of Buenos Aires. While still an undergrad, I had my first approach to what being in a lab and doing research meant. During that time I started investigating the efferent system of Zebrafish neuromasts. Once I graduated from college, I decided to keep investigating the auditory efferent system, in particular, GABA's role during development. By performing electro-physiological recordings of inner hair cells along with optogenetic stimulation, we were able to demonstrate that GABA and ACh are co-released from Medial Olivocochlear Neurons. After getting my PhD degree, I had the honor of joining Holt/Geleoc lab as a postdoctoral fellow, where I hope to contribute to our understanding of hair cell mecanotransduction, and ultimately, help develop gene therapy methods to restore auditory function.

 

Hobbies: cooking, dancing, sailing, diving, traveling.

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Tais.Castagnola-AT-childrens.harvard.edu

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Matthew Mun, SHBT Graduate Student

I was born and raised in Dallas-Fort Worth, Texas and went to school at the University of Texas at Austin, where I studied chemistry, biochemistry, and linguistics. Having an interest in both language and molecular biology, I joined two labs: the Stuttering and Linguistic Processing Lab under Dr. Zoi Gkalitsiou where I studied the interactions between age, multilingualism, and manifestations of stuttering, as well as the lab of Dr. Richard Aldrich, where I studied the coupled calcium/voltage gating mechanism of BK channels and the functional domains of other ion channels. Wishing to combine my interests in speech-hearing and molecular biology, I joined the Harvard Speech and Hearing Bioscience and Technology program as a PhD student, where I have since joined the lab of Drs. Jeffrey Holt and Gwenaelle Geleoc at Boston Children’s Hospital/Harvard Medical School. While here, I plan to characterize molecular components important for sensory transduction and auditory function in the inner ear, as well as potential new therapeutics for the treatment of hearing loss.

 

Hobbies: Biking, music, drawing, learning (about) languages, playing saxophone

 

Matthew.Mun-AT-childrens.harvard.edu 

 

Will Davis, Lab Manager

I was born in Louisiana and grew up in Ohio. I graduated with a BS in biology from Kent State University, then with a MSc in clinical embryology from the University of Oxford. I worked as a research assistant for several years at Case Western Reserve University in Cleveland, where I studied the development of the stria vascularis of the inner ear with Dr. Martin Basch. I then joined Boston Children’s Hospital as a lab manager. In my spare time I enjoy cycling, visiting the library, and pickling.

 

Hobbies: cycling, visiting the library, pickling

 

william.davis-AT-childrens.harvard.edu

 

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Cristobal Von Muhlenbrock, Research Assistant

I was born and raised in a small town called Iquique in the north of Chile. At 15, I had the incredible opportunity to participate in a six-month exchange program that took me to Massachusetts. It was a life-changing experience. At 17, I managed to return into the United States to pursue my dream of delving deeper into the world of science by completing a BS in Biochemistry and Molecular Biology at the University of Massachusetts, Amherst with the ultimate goal of attending Med School in the future. My interest in the Holt/Géléoc Lab's ongoing research was sparked by a personal connection. One of my family members was born with a genetic disorder that caused hearing loss.  Witnessing how profoundly it affected their life motivated me to understand the intricate mechanisms of the auditory system. The complexities of auditory transduction intrigued me, from the different structures, proteins, and processes involved in converting sound waves into electrical signals that reach the brain. I believe that gaining in-depth knowledge in this field can lead to potential treatments that can greatly improve the lives of individuals suffering from hearing impairments.

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Hobbies: Kiteboarding, Calisthenics, Weightlifting, Snowboarding, Surfing, Music

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cristobal.vonmuhlenbrockrodriguez-AT-childrens.harvard.edu

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Camille Martin, Research Assistant

I was born and raised in Wenham, Massachusetts, and eventually ventured to Upstate New York where I earned a BA in Biology from Hamilton College. While I Initially planned to pursue a career in medicine, my experiences at Hamilton revealed my passion for research and a strong interest in genetic therapies and regenerative/stem cell biology. I have had the privilege of working on two research projects in both industry and academic settings, including an internship at New England Biolabs focused on optimizing deaminase immunity proteins in vitro, and a year-long senior thesis at Hamilton investigating genetic barcoding and biodiversity. I was particularly drawn to the Holt/Géléoc lab’s dedication to research on Usher Syndrome, as well as its supportive and collaborative culture. During my time at Boston Children’s Hospital, I hope to contribute to the advancement of genetic therapies while continuing to develop a knowledge in sensory transduction alongside a group of intelligent and passionate colleagues.

 

Hobbies: Swimming, baking, music, spending time with friends and family

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Camille.Martin-AT-childrens.harvard.edu

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Katerina Anamisis, Undergrad Student Scientist

I am of Greek descent and was born and raised in Florida. I transferred from the University of Florida Honors Program to Boston College. My primary reason for transferring is to conduct research on therapeutic development for Usher syndrome type II in the Holt/Géléoc Lab. Usher syndrome type II is caused by mutations in the USH2A gene. This subtype of Usher syndrome includes moderate to severe sensorineural hearing loss from birth and progressive loss of vision, prompting retinitis pigmentosa. One of my family members was diagnosed with this condition, and I decided to combine my passion for science and medical research with my personal connection into conducting research on therapeutic intervention for patients with this condition. In the Holt/Géléoc Lab, I will be focused on pursuing therapeutic approaches for Usher syndrome type II with the ultimate goal of stopping the progression of vision loss and possibly restoring lost vision and hearing.

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Hobbies: Traveling to and roaming around new places, salsa dancing, Greek dancing, and speaking Greek

 

Katerina.Anamisis-AT-childrens.harvard.edu