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7Effect of astrocyte's optogenetic stimulation on neural network activity in Alzheimer's disease modeling in vitro
E. Mitroshina1, E. Kalinina1, S. Gudkov1,2, M. Vedunova1*
1-Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue,
603022 Nizhny Novgorod, Russia 2- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilova St., 119991 Moscow,
Russia
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, primarily affecting the elderly. AD impacts not only neurons but also glial cells, particularly astrocytes, leading to reactive astrogliosis and neuroinflammation. Astrocytes play a crucial role in regulating synaptic plasticity and neuronal excitability by releasing neuroactive substances known as gliotransmitters. Thus, examining the pathology of astroglial tissue is essential for understanding the etiology and pathogenesis of AD and developing treatment strategies. Optogenetics is a promising method for modulating cellular activity through the selective expression of opsins, which are exogenous light-sensitive protein-ion channels [1]. While traditionally used to control neuronal activity, recent studies have successfully applied optogenetics to astrocytes [2,3]. Therefore, exploring optogenetic therapy offers potential for advancing our understanding of AD mechanisms and discovering new treatments.
The aim of our study was to investigate the effect of optogenetic stimulation of astrocytes on the spontaneous bioelectrical activity of primary cultures of mouse hippocampal cells in a model of beta-amyloidosis. Fibrillar p-amyloid (3.5 ^M) was applied at each medium change starting from day 10 of culture (DIV). Cultures were infected with the viral optogenetic construct AAV-hGFAP-ChR2-EYFP at 10 DIV. Bioelectrical activity was recorded daily from days 14 to 21 in vitro using the MEA2100-2x60-System-E (Multichannel Systems, Germany). Photostimulation of cultures transduced with the optogenetic construct was conducted daily using an optogenetic kit (Thorlabs Inc., USA) with 470 nm light at 50% diode power for 30 seconds. Electrophysiological data were processed with the MEAxtd software developed in Python.
It has been shown that modeling amyloidosis from 17 DIV leads to a decrease in the level of spontaneous bioelectrical activity in primary cultures of hippocampal cells. This includes a reduction in the number of small bursts of impulses and the number of spikes in a burst. In 50% of the studied cultures, burst activity was completely absent after the 17th day of cultivation. Chronic optogenetic stimulation of astrocytes supported the bioelectrical activity of hippocampal neuron-glial networks. In all studied cultures, burst activity remained, although there was a tendency toward a decrease in the number of bursts of impulses. The number of spikes in a burst on day 21 remained unchanged relative to day 14 of cultivation. Thus, optogenetic modulation of astrocytic activity may be a potential approach to correct neurodegenerative changes.
This research was funded by contract no. 075-15-2022-293 "Center of Photonics" funded by the Ministry of Science and Higher Education of the Russian Federation.
[1] M. White, M. Mackay, R.G. Whittaker, Taking Optogenetics into the Human Brain: Opportunities and Challenges in Clinical Trial Design, J Clin Trials, 12, 33-41, (2020).
[2] A.A. Borodinova, P.M. Balaban, I.B. Bezprozvanny, A.B. Salmina, O.L. Vlasova, Genetic Constructs for the Control of Astrocytes' Activity, Cells, 10, 1600, (2021).
[3] E. Mitroshina, E. Kalinina, M. Vedunova, Optogenetics in Alzheimer's Disease: Focus on Astrocytes, Antioxidants (Basel), 12, 1856, (2023).
