Aminoglycoside antibiotics are a class of drug used to treat bacterial infections but have the unfortunate side effect of being both oto- and nephro-toxic. Deafness caused by aminoglycoside ototoxicity results from a loss of sensory hair cells from the inner ear. In vitro, two early effects of aminoglycoside exposure can be observed. First, membrane blebs are formed around the perimeter of the hair-cell apical surface. Secondly phosphatidylserine (PS), an aminophospholipid that is normally restricted to the inner leaflet of the plasma membrane, flops to the outer leaflet. This membrane damage occurs rapidly, within 90-120 seconds of drug exposure and can be completely reversed. The aim of this thesis was to determine the molecular mechanisms underlying damage repair in sensory hair cells recovering from aminoglycoside damage. TEM studies using cationic ferritin as a tracer indicates the repair process involves membrane internalisation, but recovery cannot be blocked by inhibitors of macropinocytosis, the clathrin-independent carrier (CLIC) pathway, PI3 kinase, PKC, Pak1 or of the clathrin-coated pit pathway. Damage repair is, however, prevented by the actin stabiliser jasplakinolide and the inhibitor of Protein kinase A, H-89. In addition, the CLIC pathway inhibitor EIPA has been uncovered as a reversible blocker of aminoglycoside entry into hair cells.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:668903 |
| Date | January 2015 |
| Creators | Allen, Nicola Jayne |
| Publisher | University of Sussex |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://sro.sussex.ac.uk/id/eprint/57127/ |
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