|ARGOTY, GUSTAVO - Virginia Tech|
|KOBORI, MASUKO - National Food Research Institute - Japan|
|ZHANG, LIQING - Virginia Tech|
|XIAO, WEIDONG - Temple University Medical School|
Submitted to: Journal of Probiotics & Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2016
Publication Date: 2/22/2016
Citation: Liu, L.S., Firrman, J., Argoty, G.A., Tomasula, P.M., Kobori, M., Zhang, L., Xiao, W. 2016. Genetic expression profile analysis of the temporal inhibition of quercetin and naringenin on Lactobacillus rhamnosus GG. Journal of Probiotics & Health. 4:139. doi: 10.4172/2329-8901.1000139.
Interpretive Summary: Quercetin and naringenin are among the most common plant polyphenols found in a wide spectrum of fruits and vegetables and are considered to benefit human health. However, little is known of their interactions with other food components, such as probiotics, which are found in yogurt. In this study, we investigated the individual effects of quercetin and naringenin on the growth of the probiotic, Lactobacillus rhamnosus GG (LGG), over an extended time period. The technique of RNA expression analysis was used which allowed identification of the molecular responses of LGG to either the quercetin or naringenin. The results showed that growth of LGG was initially inhibited by the polyphenols and then overcome through regulation of multiple genes of the LGG but the inhibition by the two polyphenols appeared to occur by different mechanisms. RNA expression analysis provided a more multi-dimensional understanding of how polyphenols may impact the growth of LGG, and could be applied to research on the gut microbiome.
Technical Abstract: The plant polyphenols, quercetin and naringenin, are considered healthy dietary compounds; however, little is known of their effects on the probiotic Lactobacillus rhamnosus GG (LGG). In this study, it was discovered that both quercetin and naringenin produced temporary inhibition of LGG growth, particularly at 8 hours post inoculation, with LGG eventually recovering from this suppression. The observed growth inhibition was regarded as a phenotypic response of LGG to the polyphenols; we hypothesized that the subsequent recovery was due to unknown, underlying genetic factors. The molecular response of LGG to quercetin and naringenin was determined through RNA analysis using the Helicos single molecule sequencing platform. The expression profiles of LGG grown in the presence of either quercetin or naringenin were divergent from each other, with only a few similarities, indicating that these polyphenols inhibit growth through separate mechanisms. LGG treated with quercetin demonstrated upregulation of genes associated with DNA repair and transcriptional regulation, and a decrease in expression of genes involved in metabolism and protein movement through the cell wall. LGG treated with naringenin resulted in an increase of genes associated with metabolism, and a decrease in genes involved in stress response. Results from this study demonstrate that there is a clear interaction between the polyphenols quercetin and naringenin and the probiotic LGG. The RNA expression analysis provides unique insight into the molecular response of LGG to quercetin and naringenin, revealing an identifiable pattern of gene expression.