Effect of Conversion Cocktail on Astrocyte and Neuronal Status in the Primary Hippocampal Culture of 5xFAD Mice with Angiotensin-Converting Enzyme 2 Inhibition

Neurodegenerative diseases are intricate pathological conditionscharacterized by the progressive degeneration and death of neuronsin the nervous system. As a result, researchers are increasingly focusingon strategies that use combinations of bioactive chemical compoundsto convert other, more stable cell types into functional neurons.Chemical conversion has shown particular promise in astrocyte-onlymodels; however, more realistic experimental systems include differentcell types whose interactions may influence the response to chemicalconversion. In this study, we investigated the effect of a multicomponentchemical cocktail on cells in mixed astro-neuronal cultures derivedfrom the hippocampus of transgenic mice of the 5xFAD strain, a geneticmodel of Alzheimer’s disease (AD). In addition, we recreated a modelthat simulates the reduction in ACE2 receptor activity observedin COVID-19 patients due to internalization of the receptor afterit binds to the coronavirus, in order to study the consequencesof chemical conversion upon disruption of this enzyme activity inthe brain. Our results indicate that the increase in neuronal densityand the emergence of new neurons following exposure to the conversioncocktail in complex multi-component cell systems is apparent atlater time points in cultures derived from non-transgenic animalsas well as in cultures derived from the 5xFAD mice. This may bedue to the natural increase in astroglial levels during culturedegradation. Notably, ACE2 inhibition significantly affects themorphology of individual astrocytes and neurons. When we evaluatedthe effects of the chemical cocktail, we observed that its efficacywas influenced by both the transgenic status of the culture andthe timing of the conversion cocktail administration in relationto ACE2 inhibition. Cultures derived from transgenic animals weremore sensitive to both the ACE2 inhibitor and the chemical conversionagents.