Theoretical Design, Synthesis, and In Vitro Neurobiological Applications of a Highly Efficient Two-Photon Caged GABA Validated on an Epileptic Case

Balázs Chiovini; Dénes Pálfi; Myrtill Majoros; Gábor Juhász; Gergely Szalay; Gergely Katona; Milán Szőri; Orsolya Frigyesi; Csilla Lukácsné Haveland; Gábor Szabó; Ferenc Erdélyi; Zoltán Máté; Zoltán Szadai; Miklós Madarász; Miklós Dékány; Imre G Csizmadia; Ervin Kovács; Balázs Rózsa; Zoltán Mucsi

doi:10.1021/acsomega.1c01164

Theoretical Design, Synthesis, and In Vitro Neurobiological Applications of a Highly Efficient Two-Photon Caged GABA Validated on an Epileptic Case

ACS Omega. 2021 Jun 3;6(23):15029-15045. doi: 10.1021/acsomega.1c01164. eCollection 2021 Jun 15.

Authors

Balázs Chiovini^{1

2}, Dénes Pálfi¹, Myrtill Majoros¹, Gábor Juhász^{1

2}, Gergely Szalay², Gergely Katona², Milán Szőri³, Orsolya Frigyesi⁴, Csilla Lukácsné Haveland⁴, Gábor Szabó⁵, Ferenc Erdélyi⁵, Zoltán Máté⁵, Zoltán Szadai¹, Miklós Madarász², Miklós Dékány⁶, Imre G Csizmadia⁷, Ervin Kovács^{4

8}, Balázs Rózsa^{1

2}, Zoltán Mucsi^{3

4}

Affiliations

¹ The Faculty of Information Technology, Pázmány Péter Catholic University, 50 Práter str., H-1083 Budapest, Hungary.
² Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary.
³ Institute of Chemistry, Faculty of Materials Science and Engineering, University of Miskolc, H-3515 Miskolc, Hungary.
⁴ Chemistry Department, Femtonics Limited, Tűzoltó str. 59, H-1094 Budapest, Hungary.
⁵ Transgenic Facility, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary.
⁶ Gedeon Richter Plc, Gyömrői str. 19-21, H-1103 Budapest, Hungary.
⁷ Department of Chemistry, University of Toronto, 80 St. George Street, M5S 3H6 Toronto, Ontario, Canada.
⁸ Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, 2 Magyar tudósok körútja, H-1117 Budapest, Hungary.

Abstract

In this paper, we present an additional, new cage-GABA compound, called 4-amino-1-(4'-dimethylaminoisopropoxy-5',7'-dinitro-2',3'-dihydro-indol-1-yl)-1-oxobutane-γ-aminobutyric acid (iDMPO-DNI-GABA), and currently, this compound is the only photoreagent, which can be applied for GABA uncaging without experimental compromises. By a systematic theoretical design and successful synthesis of several compounds, the best reagent exhibits a high two-photon efficiency within the 700-760 nm range with excellent pharmacological behavior, which proved to be suitable for a complex epileptic study. Quantum chemical design showed that the optimal length of the cationic side chain enhances the two-photon absorption by 1 order of magnitude due to the cooperating internal hydrogen bonding to the extra nitro group on the core. This feature increased solubility while suppressing membrane permeability. The efficiency was demonstrated in a systematic, wide range of in vitro single-cell neurophysiological experiments by electrophysiological as well as calcium imaging techniques. Scalable inhibitory ion currents were elicited by iDMPO-DNI-GABA with appropriate spatial-temporal precision, blocking both spontaneous and evoked cell activity with excellent efficiency. Additionally, to demonstrate its applicability in a real neurobiological study, we could smoothly and selectively modulate neuronal activities during artificial epileptic rhythms first time in a neural network of GCaMP6f transgenic mouse brain slices.