Stepanyan Lab

The goal of Ruben Stepanyan's lab The goal of the lab’s research is to study hair cell mechanosensitivity and calcium homeostasis in normal and pathological conditions.  Mechanosensitivity of hair cells is necessary for our hearing while calcium is an essential modulator of mechano-electrical transduction. 

During excessively loud sounds and noise a substantial amount of calcium ions enter hair cells through mechanotransduction channels.  Therefore it is important for hair cells to be able to buffer and extrude excessive Ca2; compromised calcium balance is a significant factor leading to hair cell death. 

Outer hair cells, one of the two types of auditory hair cell in mammalian cochlea, rely on mobile calcium buffers and plasma membrane calcium pumps to regulate calcium levels.  A particular interest of the lab is establishing the exact mechanism by which sounds and noise lead to calcium overload in basal, high frequency, outer hair cells.  Generally, hearing loss occurs at the higher frequencies first, and it is basal outer hair cells, which are the most vulnerable to a variety of insults, including loud noise and ototoxic drugs.  The following methods will be commonly utilized in the lab – patch-clamp, fluorescent imaging, electron microscopy, and audiology techniques.