Apoptosis in inner ear sensory hair cells

Abstract

Apoptosis, or controlled cell death, is a normal part of cellular lifespan. Cell death of cochlear hair cells causes deafness; an apoptotic process that is not well understood. Worldwide, 1.3 billion humans suffer some form of hearing loss, while 360 million suffer debilitating hearing loss as a direct result of the absence of these cochlear hair cells (Worldwide Hearing, 2014). Much is known about apoptosis in other systems and in other cell types thanks to studies done since the mid-20th century. Here we review current literature on apoptosis in general, and causes of deafness and cochlear hair cells loss as a result of apoptosis. The family of B-cell lymphoma (Bcl) proteins are among the most studied and characterized. We will review current literature on the Bcl2 and Bcl6 protein interactions in relation to apoptosis and their possible roles in vulnerability and survival of cochlear hair cells.

DNA methylation dynamics during embryonic development and postnatal maturation of the mouse auditory organ of Corti

“…Typically, LMRs tend to be enriched for H3K4me1, DNase I hypersensitive sites (DHS) and p300/CBP. We identified 31,916,17,945 and 31,564 UMRs and 174,347,237,282 and 206,144 LMRs in E16.5, P0 and P22 methylomes, respectively ( Fig. 1c; Additional file 2: Table S1), which have the expected percent methylation and genome localization characteristics (Additional file 1: Figure S1c-h).…”

“…Interestingly, we found that a Bach2 motif was significantly enriched across all time points (E16.5, P0 and P22, p = 1x10 -9 , 1x10 -16 , 1x10 -76 , respectively). This TF plays a role in the Bcl6-Bcl2-p53 axis in controlling apoptosis in several non-inner ear tissue types (reviewed in [31]), as well as has late onset expression in the developing chick ridge, otic cup and/or neural crest [32]. However, Bach2 has not been reported to play a role in the inner ear development.…”

Complementary and distinct roles of autophagy, apoptosis and senescence during early inner ear development

“…In the adult inner ear, apoptosis is a crucial mechanism to maintain neuronal and sensory cell populations, being this a field of renewed research interest to identify drug-targets and develop novel therapies to prevent cell death and hearing loss (Morrill and He, 2017;Wang and Puel, 2018).…”

A Prospective Observational Study of Temporalis Fascia with Tragal Perichondrium as Graft Material in Type I Tympanoplasty

“…This system of epithelially lined channels and spaces is filled with endolymph (Scarpa's fluid); the utricular duct, the saccular duct, and the ductus reuniens interconnect the major structures [18].…”

“…The scala media filled with end lymph, which resemble intracellular fluid (low in sodium, high in potassium) in composition. The electrolyte composition of the scala media causes the endocochlear potential, which is +60 to +100 mV relative to the perilymph [18].…”