Abstract
Purpose :
Oxidative stress plays a critical role in retinal pigment epithelium (RPE) pathophysiology in age-related macular degeneration (AMD), but it remains incompletely understood how RPE cells respond to oxidative stress. The present study was carried out to identify and quantify differentially expressed proteins involved in steroid hormone transport and metabolism in a human telomerase reverse transcriptase (hTERT)-immortalized RPE cell line exposed to chemically induced oxidative stress.
Methods :
hTERT RPE-1 cells (American Type Culture Collection product number CRL-4000) were treated with 100μM tert-butyl hydroperoxide (tBHP) for 24 hours. After eliciting oxidative stress, cell lysates were prepared for tandem mass tag (TMT) labeling, liquid chromatography (LC), LC-mass spectrometry, and TMT quantitation. Data was collected, reconciled, organized, and Gene Ontology (GO) and functional category analyses were conducted.
Results :
Induction of oxidative stress altered the expression of proteins involved in steroid hormone activity, including proteins involved in sterol uptake, transport and metabolism, specifically from the GO molecular function categories ‘low-density lipoprotein receptor binding’ (GO:0050750), ‘lipoprotein receptor binding’ (GO:0070325), and from the GO biological function categories ‘regulation of intracellular cholesterol transport ‘ (GO:0032383) and ‘C21-steorid hormone biosynthetic process’ (GO:0006700). Oxidative stress increased expression of seven proteins involved in cellular sterol uptake and metabolism by between 6.6- and 42.8-fold and downregulated the expression of 11 proteins by between 5.1- and 27.7-fold.
Conclusions :
hTERT-RPE-1 cell responses to oxidative stress involve the differential up- and down-regulation of proteins that are part of sterol/steroid hormone transport and synthesis. Identification of these proteins provides additional insights into the role of sterol/steroid hormones in RPE cell susceptibility to oxidative stress and might instruct the development of novel therapeutics for AMD targeting affected steroid hormone transport and metabolism proteins.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.