Numerous chronic lung diseases are characterised by oxidative stress or more accurately, perturbations in redox cycling and signalling. Cellular redox alterations lead to phenotypic adaptations such as increased cell proliferation, altered differentiation and induction of apoptosis. Biomarkers that reflect changes in cellular oxidation states as a function of normal redox signalling as well as following environmental insults would be extremely useful for studying disease processes in the lung in vitro and in vivo. One current area of interest in this field is the Peroxiredoxins (Prxs), a family of ubiquitously expressed antioxidant (AO) enzymes. The aim of this project was to assess the utility of measuring the changes in Prx expression levels and oxidation states as a quantitative biomarker of oxidative lung injury. Utilising normal human bronchial epithelial (NHBE) primary cells, which were cultured at an air-liquid interface (ALI), Prx status was analysed throughout culture morphogenesis, and following oxidative insult via glucose oxidase (GOx) and cigarette smoke (CS) exposures. Human in vivo correlation was also undertaken, using lung tissue from COPD (GOLD4) patients. Results were analysed using conventional toxicology, Western blotting (WB) and immunohistochemistry (IHC) techniques. Preliminary results revealed elevated basal levels of oxidative stress within the NHBE model, which was alleviated via the addition of AO to the media. Following GOx and CS exposures, there was increased Prx hyperoxidation in conjunction with variations in expression. A dose-dependant response to GOx and CS was observed in the NHBE cultures +AO. Variations in Prx expression levels and oxidation state were also detected throughout the in vivo correlation, with specific Prx responses observed in the different stages of airway remodelling. The Prxs were determined to be sensitive and reliable biomarkers of intracellular oxidative stress, injury severity and epithelial remodelling, thus indicating a role for the Prxs as an 'early stage' biomarker, with disruptions in redox state occurring in advance of phenotypic or morphological adaptations. Additionally, by eliminating the issue of interspecies reactivity, there may be a potential role for the NHBE-Prx system as an in vivo pre-screening tool.
|Source Sets||Ethos UK|
|Type||Electronic Thesis or Dissertation|
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