Prof. Christian Andre Amatore @ FLOGEN SIPS 2022 Yoshikawa Intl. Symposium on Oxidative Stress #2

FLOGEN SIPS 2022: Yoshikawa International Symposium on Oxidative Stress for Sustainable Development of Human Beings (2nd international Symposium)

Presenter:
Prof. Christian Andre Amatore, CNRS & PSL, French Academy of Sciences, Paris, France

Title:
Nanometer-sized electrochemical probes for intracellular measuring ROS/RNS in single cells and cellular organelles

Abstract
Oxidative stress conditions are encountered by all aerobic organisms during their whole life. Indeed, aerobic cells mostly derive their energy from the intracellular enzyme-catalyzed oxidation of fat and sugars to CO2. Also, metalloenzymes which are central actors of the respiratory chain in mitochondria are generally good reducing agents, prone to open side routes leading to O2 reduction to superoxide ion (O2•-) that is the precursor of a series of hazardous species collectively named as “reactive oxygen species (ROS)” and “reactive nitrogen species (RNS)” [1,2]. ROS and RNS may induce molecular damages to almost all organic compounds performing biological functions (nucleic acids, proteins, cells carbohydrates and lipids, etc.) – a situation termed “oxidative stress” when it runs out of control. Even without exposure to radiation or other photo-biological effects, oxidative stress can bring about such pathological conditions as inflammation, carcinogenesis, Parkinson and Alzheimer diseases, and various autoimmune illnesses, as well as accelerated ageing. The primary ROS/RNS, viz., hydrogen peroxide, peroxynitrite ion, nitric oxide, and nitrite ion, can be oxidized at different electrode potentials and therefore detected and quantified by electroanalytical techniques [3]. Nanometer-sized electrochemical probes with cylindrical shapes do not experience this problem since they can penetrate across the cell membranes that reseal around their shaft (7). They are then especially suitable for measuring ROS/RNS in single cells and cellular organelles. In this paper, we will survey recent advances in localized measurements of ROS/RNS inside single cells. Application of this method will be presented for detection of ROS/RNS in phagolysosomes during phagocytosis by macrophages (4,5). We will also evidence using these methods that remediation of Oxidative Stress in neurons artificially placed under Parkinson Disease conditions avoids the impeachment of synaptic communication when the neurons are pre-treated with Harpagide, a natural sugar derivative which alleviate the oxide stress borne by mitochondria (9).

References:

(1) B. Halliwell, J.M.C. Gutteridge, Free Radicals in Biology and Medicine, 3rd ed., Oxford University Press, Oxford, 1999.

(2) F. Murad: Discovery of Some of the Biological Effects of Nitric Oxide and its Role in Cell Signaling. Nobel Lecture for Medicine, 1998, https://www.nobelprize.org/uploads/20...

(3) C Amatore, S. Arbault, M. Guille, F. Lemaître: Electrochemical monitoring of single cell secretion: vesicular exocytosis and oxidative stress. Chem. Rev. 108 (2008) 2585–2621.

(4) K. Hu, Y.L. Liu, A. Oleinick, M.V. Mirkin, W.H. Huang, C. Amatore: Nanoelectrodes for Intracellular Measurements of Reactive Oxygen and Nitrogen Species in Single Living Cells. Curr. Opin. Electrochem., 22, 2020, 44-50, and refs therein.

(5) Y.T. Qi, H. Jiang, W.T. Wu, F.L. Zhang, S.Y. Tian, W.T. Fan, Y.L. Liu, C. Amatore, W.H. Huang: Homeostasis Inside Single Activated Phagolysosomes: Quantitative and Selective Measurements of sub-Millisecond Dynamics of ROS/RNS Production with a Nanoelectrochemical Sensor. J. Am. Chem. Soc., 144, 2022, 9723-9733.