PhD.Dissertation:Hamza Yusuf Altun
INVESTIGATION OF HYDROGEN PEROXIDE AND NITRIC OXIDE SIGNALING UTILIZING GENETICALLY ENCODED BIOSENSORS
Hamza Yusuf Altun
Molecular Biology Genetics and Bioengineering, PhD Dissertation, 2024
Thesis Jury
Prof. Dr. Mehmet Selim Çetiner(Thesis Advisor),
Asst. Prof. Alex Lyakovich
Asst. Prof. Nur Mustafaoğlu Varol
Asst. Prof. Ahmet Katı
Prof. Dr. Batu Erman
Date & Time: 22/07/2024 – 09:00 AM
Place: FENS G035
Keywords : Hydrogen Peroxide, Nitric Oxide, Genetically Encoded Biosensors, Redox Signaling, Physiological Normoxia
Abstract
The relationship between hydrogen peroxide (H2O2) and nitric oxide (NO) is a critical yet complex aspect of redox biology, with significant implications for cellular signaling and oxidative stress-related diseases. This study aims to demonstrate this relationship using genetically encoded biosensors, HyPer7 for H2O2 and O-geNOp for NO, in live-cell imaging. We developed and optimized these tools to achieve high selectivity and spatial resolution, addressing challenges related to simultaneous measurement of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Our experiments demonstrated that cells adapted to physiological normoxia (5 kPa O2) exhibit enhanced antioxidant capacity and NO bioavailability compared to those adapted to hyperoxia (18 kPa O2). Using a dual-biosensor endothelial cell line, we investigated the effects of H2O2 production on NO dynamics and discovered that physiological normoxia conditions significantly improve cellular redox balance. These findings provide new insights into the interplay between H2O2 and NO, highlighting the importance of maintaining physiological O2 levels for optimal cellular function. The results also underscore the potential of genetically encoded biosensors as powerful tools for studying redox signaling in live cells, paving the way for novel therapeutic strategies targeting oxidative stress-related pathologies.