ABSTRACT Neurofibromatosis Type 2 (NF2) is a genetic condition in which specific types of tumors form in various locations throughout the body. Though the majority of these tumors grow slowly, the location of certain tumors can cause significant dysfunction. One of these tumor types grows on the vestibular branch of cranial nerve VIII, the vestibulocochlear nerve. The cells which gives rise to this tumor type is the Schwann cell, a glial cell type. Thus, this tumor type is termed a vestibular Schwannoma (VS), a mass of Schwann cells on the vestibular nerve. Due to the proximity of skull base cranial elements, a VS can cause dysfunction like hearing loss, balance issues, or facial paralysis. The current treatment options are limited to invasive surgical procedures which can create complications. Current knowledge of the mechanisms governing the development and growth of VS is limited due to the fact that research has been restricted to mouse and simple human cell culture systems. This proposed study will provide vertical impact by modeling NF2 in a new system, the inner ear organoid. Inner ear organoid induction involves step-wise differentiation in a 3D culture system using pluripotent stem cells. Inner ear organoids develop full sensory circuits of hair cells, sensory neurons, and myelinating Schwann cells in vitro. We will create this model by introducing a genetic manipulation in our stem cells which mimics the genetics of NF2 patients. In Aim 1, we will analyze biochemical pathways known to be affected in NF2 patients in this new NF2 inner ear organoid. In Aim 2, we will evaluate druggable targets in order to assess therapeutic effectiveness to counteract the introduced NF2 mutation. This study will provide insight into the tumorigenic processes of VS.

PROJECT NARRATIVE Neurofibromatosis Type 2 (NF2) is a disease with multiple manifestations, including the vestibular schwannoma, a tumor of Schwann cells. Patients with NF2 can experience hearing loss, facial paralysis, and vertigo due to the location of a vestibular schwannoma on cranial nerve VIII. In this study, we will model NF2 using a human pluripotent stem cell culture system.