Polarized Patterning of the Vestibular Maculae
The utricle and saccule (vestibular maculae) are otolith organs of the inner ear that contain sensory cells that are essential for inner ear function. Among these cells are mechanotransductive hair cells which detect deflection in a specific vector via their apically localized stereociliary bundles. A single tubulin rich kinocilium sits alongside the actin-dense bundles where it is positioned asymmetrically indicative of the maximum deflection sensitivity of a single hair cell. Hair cells are arranged in the utricle and saccule in opposing orientations about a line of polarity reversal (LPR). The formation of this LPR depends on a transcription factor Emx2. But the protein effectors downstream of Emx2 which move the kinocilium to its asymmetric position, have not yet been identified. The current goal of my PhD dissertation is to identify what effector proteins give rise to this polarized pattern.
Spiral Ganglion Neuron Turning in the Developing Cochlea
The cochlea is a snail-shell shaped organ within our inner ear that also contains hair cells which meachanically transduce pressure waves into meaningful sounds for our brain. These hair cells are innervated by spiral ganglion neurons (SGNs) which are so named because of their characteristic spiraling turns from base to apex along the cochlear length. Recent work by my fellow labmate Satish Ghimire revealed that the transmembrane protein Van Gogh Like 2 (Vangl2) plays an important role in this process. Vangl2 is known to have a cell-autonomous effect in axon guidance in the spinal cord. However, uniquely we found that there was a non-autonomous function of Vangl2 from the nearby environment which has an effect on the correct guidance and innervation of hair cells in the cochlea by type II SGNs. To learn more about this research, please read our publication a non-autonomous function of the core PCP protein VANGL2 directs peripheral axon turning in the developing cochlea.