Avian-inspired Regenerative Therapies for Hearing Loss

PROJECT SUMMARY Hearing loss is a prevalent condition affecting millions of individuals worldwide, primarily caused by the irreversible loss of auditory hair cells. While non-mammalian species possess the remarkable ability to regenerate hair cells, mammals, including humans, lack this regenerative capacity. Therefore, understanding the regenerative potential of hair cells in mammals is crucial for developing effective therapies to restore hearing. The objective of this project is to decipher the mechanisms for inducing S-phase entry in adult mammalian supporting cells and investigate their regenerative potential for sensory hair cell regeneration in the auditory system. In AIM 1, the study will align transcriptomic and epigenetic data at single-cell resolution to establish a baseline profile of supporting cells before, during, and after hair cell loss. The analysis will identify the molecular signatures associated with the quiescent state of supporting cells in mammals and explore the influence of epigenetic factors on the regenerative incapability of supporting cells and their differentiation into functional hair cells. Comparative analysis with chicken datasets will refine strategies for inducing cell cycle re-entry in supporting cells. AIM 2 focuses on developing a strategy to specifically target adult supporting cells after acute and chronic hair cell damage. The study will employ an inducible gene expression strategy in adult supporting cells using adeno- associated virus (AAV)-mediated gene transfer. AIM 3 investigates the possibility to induce division in mature supporting cells and hair cell fate specification using a co-misexpression approach with multiple transcription factors. The project will utilize innovative techniques such as multi-omics low-depth single-cell RNA-seq and single- nucleus ATAC-seq to characterize supporting cells at different time points post-hair cell insult. The employment of Fbxo2VHC/WT mice and inducible gene expression strategies using AAV-mediated gene transfer will ensure accurate representation and temporal control of gene expression in supporting cells. The use of various controls and statistical methods will ensure robust data analysis and mitigate technical biases. The outcomes of this research will shed light on the molecular and epigenetic identity of supporting cells, identify potential targets for therapeutic interventions, and refine strategies for inducing cell cycle re-entry and hair cell regeneration. Ultimately, this project aims to contribute to the development of regenerative therapies for hearing loss, providing hope for millions of individuals worldwide.