Treatment with polyphenols and probiotics counteracts LPS-induced morphological and functional polarization of BV-2 Microglia

Neuroinflammation is implicated in the onset of neurodegenerative diseases and occurs primarily as a result of hyperactivation of glial cells in the central nervous system (CNS). Microglia cells respond to insults through the release of inflammatory mediators such as cytokines and chemokines. Our research focuses on the study of some nutraceutical compounds that promote the morpho-functional bias of microglia toward an anti-inflammatory phenotype. We have recently demonstrated the presence of bioactive compounds in blueberry extracts that can polarize LPS-stimulated BV2 microglial cells toward an anti-inflammatory phenotype. In addition, we considered the role of the gut-brain axis and gut dysbiosis in the induction of pathological processes at the CNS level. Here, we demonstrated that a wave-treated Saccharomyces cerevisiae stock reverts LPS-stimulated microglial cells toward an anti-inflammatory phenotype. Microglial polarization was assessed by analysis of cytokine expression, M1 and M2 markers, and antioxidant enzymes by RT-PCR and immunofluorescence. Evaluation of cell morphology, analysis of pro- and anti-inflammatory cytokines and key markers of microglial activation (iNOS and ARG-1) expressed by cells under different experimental conditions demonstrated the ability of the factors analyzed to direct microglial activation toward an anti-inflammatory condition. Overall, our data suggest that the molecules we analyzed may drive microglial polarization toward an anti-inflammatory phenotype to counteract the development of chronic-neurodegenerative diseases.