Bacterial contact induces morphological and functional changes in primary neural cortical cell cultures

Abstract

The interaction of bacteria with various somatic cell types is an exciting emerging field. Despite the known effects of microbiota on the gut-brain axis, very little is known about the direct interactions that bacteria could have with neurons, both in terms of molecular mechanisms and information transfer. In order to study these communication mechanisms, this study designs an in vitro model to co-cultivate microbiota-bacteria Lactiplantibacillus plantarum with neural cortical cells and analyzes the effects of this process in both populations. Here, we show how bacteria and neurons can be co-cultured, and demonstrate a novel integrated platform that facilitates the analysis of neuronal-bacteria communication. The results we obtained showed that L.plantarum is capable of adhering to the surface of the neural culture and the amount of attached bacteria increases with co-culture time. In addition, neural co-cultured cells show morphological and functional changes in the expression of key proteins in neuroplasticity such as Synapsin I and pCREB. Finally, using real-time optical (calcium signaling) readouts, we show that neural cells react to the co-culture with bacteria by increasing cytoplasmatic Ca2+ signaling. Our proof-of-principle data reveal crosstalk between bacterial and neural co-cultured cells and illustrate a novel example of cross-kingdom communication between highly diverse cell types. The ability to eavesdrop on information passing between these two very different levels of biological organization will facilitate insight into evolutionary cell biology and could impact the understanding of brain-bacteria communication for diagnosis of neuronal states in health and disease.