ORALS

SESSION: OxidativeMonPM2-R1	Yoshikawa International Symposium (2nd Intl. Symp. on Oxidative Stress for Sustainable Development of Human Beings)
Mon. 28 Nov. 2022 / Room: Ballroom B
Session Chairs: Alexander Oleinick; Christian Andre Amatore; Session Monitor: TBA

16:20: [OxidativeMonPM210] OS
Nanometer-sized electrochemical probes for intracellular measuring ROS/RNS in single cells and cellular organelles
Christian Andre Amatore¹ ; Keke Hu² ; Alexander Oleinick³ ; Irina Svir⁴ ; Wei-hua Huang⁵ ; Yan-ling Liu⁵ ; ¹CNRS & PSL, French Academy of Sciences, Paris, France; ²Goteborg University, Gothenburg, Sweden; ³CNRS, Paris, France; ⁴Ecole Normale Superieure, Department Chemistry, PARIS, France; ⁵Wuhan University, Wuhan, China;
Paper Id: 445 [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:
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/2018/06/murad-lecture.pdf
(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.

SESSION: OxidativeMonPM2-R1	Yoshikawa International Symposium (2nd Intl. Symp. on Oxidative Stress for Sustainable Development of Human Beings)
Mon. 28 Nov. 2022 / Room: Ballroom B
Session Chairs: Alexander Oleinick; Christian Andre Amatore; Session Monitor: TBA

17:10: [OxidativeMonPM212] OS
Modeling of quantitative nano-amperometric measurement of sub-quantal glutamate release by living neurons
Giovanni Pireddu¹ ;⁰ ; Xiaoke Yang² ; Fu-li Zhang² ; Yan-ling Liu² ; Irina Svir³ ; Alexander Oleinick⁴ ; Wei-hua Huang² ; Christian Andre Amatore⁵ ; ¹CNRS, Ecole Normale Superieure, Sorbonne University, Paris, France; ²Wuhan University, Wuhan, China; ³Ecole Normale Superieure, Department Chemistry, PARIS, France; ⁴CNRS, Paris, France; ⁵CNRS & PSL, French Academy of Sciences, Paris, France;
Paper Id: 447 [Abstract]

Glutamate (Glu) is a crucial fundamental excitatory neurotransmitter released through vesicular exocytosis in the central nervous system. Dysregulation of the glutamate uptake by neurons and glial cells result in increase of the glutamate extracellular concentration leading eventually to excitotoxicity associated with increased oxidative stress and neurodegeneration [1]. Hence, quantitative measurements and interpretation of intravesicular Glu and of transient exocytotic release contents directly from individual living neurons are highly desired for understanding the mechanisms (full or sub-quantal release?) of synaptic transmission and plasticity. However, this could not be achieved so far due to the lack of adequate experimental strategies relying on selective and sensitive Glu nanosensors. We will show that a novel electrochemical Glu nanobiosensor based on a single SiC nanowire [2] is prone to selectively measure in real-time Glu fluxes released via exocytosis by large Glu vesicles (ca. 125 nm diameter) present in single hippocampal axonal varicosities as well as their intravesicular content before exocytosis by IVIEC. Combination of these two series of measurements revealed a sub-quantal release mode in living hippocampal neurons, viz., only ca. one third to one half of intravesicular Glu molecules are released by individual vesicles during exocytotic events. Importantly, this fraction remained practically the same when hippocampal neurons were pretreated with L-Glu-precursor L-glutamine, while it significantly increased after zinc treatment, although in both cases the intravesicular contents before release were drastically affected. Finally, the simulations of the electrochemical monitoring of the glutamate release events will be presented. The obtained theoretical results support the quantitative measurements with the enzymatic electrode. In addition, simulation results will also serve to discuss the meaning and adequacy of pre-calibrations performed in bulk solutions [3] to assess the analytical properties of enzyme-based electrochemical nanosensors aimed to detect fast transient release events.

References:
[1] A.A. Kritis et al. Front. Cell. Neurosci. 9 (2015) 91.
[2] X. Yang, et al. Angew. Chem. Int. Ed. 60 (2021) 15803–15808.
[3] C.P. McMahon, et al. Analyst 131 (2006) 68–72.

SESSION: OxidativeWedPM3-R1	Yoshikawa International Symposium (2nd Intl. Symp. on Oxidative Stress for Sustainable Development of Human Beings)
Wed. 30 Nov. 2022 / Room: Ballroom B
Session Chairs: Yoichiro Sugiyama; Session Monitor: TBA

18:15: [OxidativeWedPM314] OL
Stretchable Electrochemicl Sensor for Real Time Monitoring of ROS/RNS Signaling and Oxidative Stress in Mechanotransduction
Wen-ting Fan¹ ; Yan-ling Liu¹ ; Wei-hua Huang¹ ; ¹Wuhan University, Wuhan, China;
Paper Id: 556 [Abstract]

Cells in the body reside in dynamic mechanical milieus and can sense mechanical forces and then translate them into biochemical signals via mechanotransduction. Reactive oxygen/nitrogen species (ROS/RNS) are closely involved in cellular oxidative stress and physiopathological states, and real-time acquiring the information of ROS and RNS signaling during cell mechanotransduction is vitally important to reveal their complicated roles. Owing to rapid response and excellent sensitivity, electrochemical sensing has been extensively used for tracking ROS/RNS signaling in living cells. However, conventional electrochemical sensors are rigid and fail to comply with the shape changes of soft cells, and this greatly limits the accurate measurement of ROS/RNS signaling during cell mechanotransduction. To this end, we have designed a series of stretchable electrodes based on gold nanotubes, carbon nanotubes and conductive polymer nanofibers [1,2]. These sensors possess good electrochemical stability against mechanical deformations and can be easily deformed to achieve the dynamic stretching of cells. Further, we have also introduced high-performance catalysts (e.g, platinum nanoparticles and biomimetic catalysts) to confer the stretchable sensing interfaces with prominent electrocatalytic property toward ROS and RNS [3]. Based on these stretchable electrochemical sensors, we have successively achieved the real-time monitoring of stretch-induced NO and H2O2 molecules [3,4], and the simultaneous monitoring of them by a single device during endothelial mechanotransduction [5]. Besides, the developed stretchable electrochemical sensors have been also employed to explore the ROS and RNS signaling during mechanotransduction of chondrocytes and lung cells, which demonstrate excessive or acute mechanical loading can evoke severe oxidative stress [2]. These researches present efficient platforms to evaluate the oxidative stress level in dynamic mechanotransduction, which benefit to the understanding of the role of mechanical cues in cell biology.

References:
[1] Y.L. Liu, Z.H. Jin, Y.H. Liu, X.B. Hu, Y. Qin, J.Q. Xu, C.F. Fan, W.H. Huang. Angew. Chem. Int. Ed. 55 (2016) 4537-4541.
[2] Y.L. Liu, W.H. Huang. Angew. Chem. Int. Ed. 60 (2020) 2757-2767.
[3] W.T. Fan, Y. Qin, X.B. Hu, J. Yan, W.T. Wu, Yan, Y.L. Liu, W.H Huang. Anal. Chem. 92 (2020) 15639-15646.
[4] Y.L. Liu, Y. Qin, Z.H. Jin, X.B. Hu, M.M. Chen, R. Liu, C. Amatore, W.H Huang. Angew. Chem. Int. Ed. 56 (2017) 9454-9458.
[5] W.T. Fan, Y. Zhao, W.T. Wu, Y. Qin, J. Yan, Y.L. Liu, W.H Huang. Anal. Chem. 94 (2022) 7425-7432.