(PO82) Complement Signaling Pathways in Dental Pulp Stem Cells under Hypoxia

Abstract: Several studies have shown the involvement of C5a/C3a in response to pulpal inflammation due to caries or trauma. C5a and oxygen levels are crucial in controlling the odontogenic differentiation of dental pulp stem cells (DPSCs) during pulpal inflammation. Therefore, further insight is needed about the expression of complement system genes to allow for a better understanding of the involvement of DPSCs in the regenerative/healing mechanisms of dental pulp. The aim of this study is to investigate key complement candidate genes expressed in hypoxic conditions. DPSCs were isolated from healthy adult third molars. The cells, supplemented with 1% serum-containing media or osteogenic media, were cultured in a hypoxic chamber for 21 days. RNA was isolated and sequenced using NextSeq. The RNA-Seq reads were processed for normalization using DESeq2. The count data was imported into the R package for analysis and sequence mapping to the appropriate gene. Statistical analysis was conducted using DESeq2 (p < .05) to determine differences in transcription and subsequent translation between groups. There were 14 over-expressed and 14 under-expressed genes that differed in normoxia compared to hypoxic conditions. Over-expressed genes included clusterin, CD59 molecule, and complement-C1s. Under-expressed genes included complement-C4A, complement-C2, and coagulation-factor-IX. This study shows that complement genes (e.g., clusterin) are involved with NF-Kappa-B signaling pathways related to DPSC differentiation. Additionally, negative regulation of complement activation occurs through CD59 expression. Using statistical analyses, gene expression profiles were captured that identify complement regulation and pathways active in DPSCs. These isolated genes found in this study can serve as key biomarkers for pulp tissue engineering.