Search

The development of techniques for tracking active ferrous iron (Fe 2+ ) distribution has greatly promoted the biological studies of iron. Here, we present an innovative application of a 3D two-photon fluorescent probe for Fe 2+ tracking in the epileptic mouse brain, which has expanded the toolbox of screening for iron homeostasis regulators and contributed to the discovery of new chemical entities for the treatment of epilepsy. For complete details on the use and execution of this protocol, please refer to Shao et al. (2022)., Competing Interests: Declaration of interests Nanjing Normal University Office of Technology and Intellectual Property is in the process of filing a patent protection of applications of the reported probe; Y.Q. and C.W.S. are named as co-inventors., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Myeloperoxidase (MPO)-mediated oxidative stress has been suggested to play an important role in the pathological dysfunction of epileptic brains. However, there is currently no robust brain-imaging tool to detect real-time endogenous hypochlorite (HClO) generation by MPO or a fluorescent probe for rapid high-throughput screening of antiepileptic agents that control the MPO-mediated chlorination stress. Herein, we report an efficient two-photon fluorescence probe (named HCP) for the real-time detection of endogenous HClO signals generated by MPO in the brain of kainic acid (KA)-induced epileptic mice, where HClO-dependent chlorination of quinolone fluorophore gives the enhanced fluorescence response. With this probe, we visualized directly the endogenous HClO fluxes generated by the overexpression of MPO activity in vivo and ex vivo in mouse brains with epileptic behaviors. Notably, by using HCP, we have also constructed a high-throughput screening approach to rapidly screen the potential antiepileptic agents to control MPO-mediated oxidative stress. Moreover, from this screen, we identified that the flavonoid compound apigenin can relieve the MPO-mediated oxidative stress and inhibit the ferroptosis of neuronal cells. Overall, this work provides a versatile fluorescence tool for elucidating the role of HClO generation by MPO in the pathology of epileptic seizures and for rapidly discovering additional antiepileptic agents to prevent and treat epilepsy., Competing Interests: Competing interest statement: Nanjing Normal University has filed a patent on the technique described herein that lists Y. Qian and C.S. as inventors.

A two-photon (TP) fluorescence probe has been developed for imaging endogenous FA fluxes during metabolic and epigenetic processes in animal models, especially in live brains.

Imbalanced iron homeostasis plays a crucial role in neurological diseases, yet direct imaging evidence revealing the distribution of active ferrous iron (Fe2+) in the living brain remains scarce. Here, we present a near-infrared excited two-photon fluorescent probe (FeP) for imaging changes of Fe2+ flux in the living epileptic mouse brain. In vivo 3D two-photon brain imaging with FeP directly revealed abnormal elevation of Fe2+ in the epileptic mouse brain. Moreover, we found that dihydroartemisinin (DHA), a lead compound discovered through probe-based high-throughput screening, plays a critical role in modulating iron homeostasis. In addition, we revealed that DHA might exert its antiepileptic effects by modulating iron homeostasis in the brain and finally inhibiting ferroptosis. This work provides a reliable chemical tool for assessing the status of ferrous iron in the living epileptic mouse brain and may aid the rapid discovery of antiepileptic drug candidates. [Display omitted] • FeP, a fluorescent probe, is suitable for brain imaging ferrous iron flux in vivo • 3D two-photon imaging reveals elevation of ferrous iron in the epileptic mouse brain • Dihydroartemisinin (DHA) can modulate iron homeostasis in the epileptic mouse • DHA exhibits a potential antiepileptic effect in the epileptic mouse model Shao et al. develop a near-infrared excited two-photon fluorescent probe for imaging ferrous iron (Fe2+) in brain. Using in vivo 3D two-photon imaging, they observe abnormal elevation of Fe2+ in the epileptic mouse brain and demonstrate that dihydroartemisinin exhibits antiepileptic effects by modulating iron homeostasis in the mouse brain. [ABSTRACT FROM AUTHOR]

Epilepsy is a chronic neurodegenerative disease, and accumulating evidence suggests its pathological progression is closely associated with peroxynitrite (ONOO−). However, understanding the function remains challenging due to a lack of in vivo imaging probes for ONOO− determination in epileptic brains. Here, the first near‐infrared imaging probe (named ONP) is presented for tracking endogenous ONOO− in brains of kainate‐induced epileptic seizures with high sensitivity and selectivity. Using this probe, the dynamic changes of endogenous ONOO− fluxes in epileptic brains are effectively monitored with excellent temporal and spatial resolution. In vivo visualization and in situ imaging of hippocampal regions clearly reveal that a higher concentration of ONOO− in the epileptic brains associates with severe neuronal damage and epileptogenesis; curcumin administration can eliminate excessively increased ONOO−, further effectively protecting neuronal cells. Moreover, by combining high‐content analysis and ONP, a high‐throughput screening method for antiepileptic inhibitors is constructed, which provides a rapid imaging/screening approach for understanding epilepsy pathology and accelerating antiseizure therapeutic discovery. [ABSTRACT FROM AUTHOR]