Probiotic bacteria Lactiplantibacillus plantarum is detected by primary neural cortical cells inducing transcriptional, morphological and functional changes

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-culture microbiota-bacteria Lactiplantibacillus plantarum with neural cortical cells and analyses the effects of this process in both populations. Here, we show how bacteria and neurons can be cocultured, and demonstrate a novel integrated platform that facilitates the analysis of neuronalbacteria 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 undergo changes in gene expression patterns and induce morphological and functional changes in the expression of key proteins in neuroplasticity such as Synapsin I and pCREB. Finally, using real-time optical (calcium signalling) readouts, we show that neural cells react to the presence and co-culture with bacteria cells increasing cytoplasmatic Ca2+ signalling. Our proof-of-principle data reveal crosstalk between these 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 or treatment of neuronal states in health and disease.