Use of Mammalian Cell Culture Models to Determine the Role of OCM in Calcium Signaling

Kim, Jin Hee
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Hearing loss is a prevalent problem worldwide. One of the critical aspects of hearing is the Ca2+ ion buffering system of the outer hair cells. It has been observed that there is an increase of Ca2+ levels after noise damage and during aging, and this can be associated with mitochondrial stress. We hypothesize that OCM will function as a buffer by helping the calcium related stress for the cells. We performed cell transfections, drug treatment, immunofluorescence, confocal imaging and analysis in order to qualitatively and quantitatively measure the cellular effects and potentially see the cellular mechanisms. We used cell culture because we can easily transfect the cells with plasmids of proteins found in the inner ear and we cannot directly isolate and manipulate outer hair cells. We specifically used Antimycin A and Thapsigargin because they are drugs that can be administered to cells to bring about mitochondrial stress that can lead to programmed cell death. By measuring the effects of these drugs on HeLa and HEK 293T cells transfected with GFP, OCM-GFP, and APV-OCM plasmids, and we observed how this stress affects the Ca2+ control and regulation. We wanted to explore how OCM affects cell survival through calcium signaling using the two drugs. In conclusion, we observed that OCM does not function as a mediator of mitochondrial stress under our specific conditions. Greater insight regarding these effects and cellular mechanisms will be helpful for further studies about inner ear mechanisms.

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