Biofilm-induced profiles of immune response gene expression by oral epithelial cells

Abstract

This study examined the oral epithelial immunotranscriptome response patterns modulated by oral bacterial planktonic or biofilm challenge. We assessed gene expression patterns when epithelial cells were challenged with a multispecies biofilm composed of Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis representing a type of periodontopathic biofilm compared to challenge with the same species of planktonic bacteria. Of the 579 human immunology genes, a substantial signal of the epithelial cells was observed to 181 genes. Biofilm challenged stimulated significant elevations compared to planktonic bacteria for IL32, IL8, CD44, B2M, TGFBI, NFKBIA, IL1B, CD59, IL1A, CCL20 representing the top 10 signals comprising 55% of the overall signal for the epithelial cell responses. Levels of PLAU, CD9, IFITM1, PLAUR, CD24, TNFSF10, and IL1RN were all elevated by each of the planktonic bacterial challenge vs the biofilm responses. While the biofilms up-regulated 123/579 genes (>2-fold), fewer genes were increased by the planktonic species (36 [S gordonii], 30 [F nucleatum], 44 [P gingivalis]). A wide array of immune genes were regulated by oral bacterial challenge of epithelial cells that would be linked to the local activity of innate and adaptive immune response components in the gingival tissues. Incorporating bacterial species into a structured biofilm dramatically altered the number and level of genes expressed. Additionally, a specific set of genes were significantly decreased with the multispecies biofilms suggesting that some epithelial cell biologic pathways are down-regulated when in contact with this type of pathogenic biofilm.

Figure 1:

Gene expression mRNA signal of genes expressed by oral epithelial cells with signal >100 to biofilm and/or planktonic bacterial challenge. The genes are ordered based upon the magnitude of signal with the biofilm challenge. The highlighted genes are those expressed by planktonic challenge with all the species that resulted in substantially (>4-fold) increased or decreased levels compared to the biofilm signal. Values denote the mean of values from 5 independent cell culture wells for the biofilms and basal levels (cells only), and duplicate cell culture wells for the planktonic bacteria.

Figure 2:

Comparison of fold difference in gene expression with biofilm or RGPL interaction with the oral epithelial cells. Genes are ordered based upon the magnitude of signal expression following biofilm challenge. Control cells represented basal production in media. Values denote the mean of 5 values for the biofilms and 3 for the RGPL.

Figure 3A-C:

Comparison of fold differences in gene expression with biofilms compared to individual planktonic bacteria, S. gordonii (A), F. nucleatum (B), and P. gingivalis (C). Highlighted genes are those increased by >8-fold or decreased by >2-fold. Values denote the mean of 5 values for the biofilms and duplicates for the planktonic bacteria.

Figure 3A-C:

Comparison of fold differences in gene expression with biofilms compared to individual planktonic bacteria, S. gordonii (A), F. nucleatum (B), and P. gingivalis (C). Highlighted genes are those increased by >8-fold or decreased by >2-fold. Values denote the mean of 5 values for the biofilms and duplicates for the planktonic bacteria.

Figure 3A-C:

Comparison of fold differences in gene expression with biofilms compared to individual planktonic bacteria, S. gordonii (A), F. nucleatum (B), and P. gingivalis (C). Highlighted genes are those increased by >8-fold or decreased by >2-fold. Values denote the mean of 5 values for the biofilms and duplicates for the planktonic bacteria.

Figure 4:

Venn diagram depicting the number of genes upregulated by (A) biofilm or planktonic bacteria and identifying overlap or unique alteration of the expression levels. (B) Provides similar comparison of gene IDs upregulated among the planktonic bacteria only.

Figure 5A-C:

Identification of genes with at least 2-fold increased expression induced by biofilms compared to all of the planktonic species. Values denote the mean of 5 values for the biofilms and duplicates for the planktonic bacteria. Asterisk (*) denotes at least p<0.01 from the other conditions.

Figure 5A-C:

Identification of genes with at least 2-fold increased expression induced by biofilms compared to all of the planktonic species. Values denote the mean of 5 values for the biofilms and duplicates for the planktonic bacteria. Asterisk (*) denotes at least p<0.01 from the other conditions.

Figure 5A-C:

Identification of genes with at least 2-fold increased expression induced by biofilms compared to all of the planktonic species. Values denote the mean of 5 values for the biofilms and duplicates for the planktonic bacteria. Asterisk (*) denotes at least p<0.01 from the other conditions.

Figure 6:

Identification of genes with at least 2-fold increased expression induced by one or more planktonic bacteria compared to the multispecies biofilm. Values denote the mean of 5 values for the biofilms and duplicates for the planktonic bacteria. Asterisk (*) denotes at least p<0.01 from the other conditions.