Response of cultured primary gingival and periodontal ligament cells to angiotensin II and IL1β challenges

Angiotensin II (Ang II) releases inflammatory mediators from several cell types. The objective of this study was to investigate the potential of Ang II to induce mRNA expression of inflammatory mediators in primary cultured fibroblast-like cells isolated from gingival and periodontal ligament tissues. A synergistic effect of co-treatment with Ang II and Interleukin-1β (IL1β) on the mRNA expression of inflammatory mediators was explored. Immunophenotyping of STRO-1, Ang II type 1 receptor (AT1R), and Ang II type 2 receptor (AT2R) was performed using flow cytometry. Cell cultures were challenged with Ang II (1 µM) for 3, 6, and 24 h with or without co-treatment with IL1β (0.1 ng/mL) for 24 h. mRNA expression of inflammatory mediators was determined using qPCR. We present, for the first time, precise quantification of AT1R and AT2R in human gingival and periodontal fibroblast-like cell types; the percentage of positive immunostaining compared to the total cell population varied from 3.35% to 5.29% for AT1R and 2.97% to 4.57% for AT2R. Ang II slightly upregulated IL6 and CCL2/MCP1 mRNA expression in gingival cells and IL8 and PTGS2/COX2 in periodontal ligament cells. IL1β upregulated IL8, IL6, CCL2/MCP1, PTGS2/COX2, and IL1β mRNA in both cell types. Co-treatment with Ang II and IL1β did not show a synergistic effect. Ang II showed a low potential to induce mRNA of inflammatory mediators, most likely owing to the low percentage of Ang II receptors in such cells and no synergistic effect with the co-treatment with IL1β.