Toll-like Receptor Expression Profile of Human Dental Pulp Stem/Progenitor Cells

• TLRs are the host's first defense line interacting with invading pathologic components.
• DPSCs through their TLRs may be exposed to such pathologic components in clinical conditions.
• Diverse TLR expression profiles of TLRs 1-10 have been described in different human MSCs.
• The study describes for the first time the distinctive TLR expression profiles of DPSCs.

IntroductionHuman dental pulp stem/progenitor cells (DPSCs) show remarkable regenerative potential in vivo. During regeneration, DPSCs may interact with their inflammatory environment via toll-like receptors (TLRs). The present study aimed to depict for the first time the TLR expression profile of DPSCs.MethodsCells were isolated from human dental pulp, STRO-1–immunomagnetically sorted, and seeded out to obtain single colony-forming units. DPSCs were characterized for CD14, CD34, CD45, CD73, CD90, CD105, and CD146 expression and for their multilineage differentiation potential. After incubation of DPSCs in basic or inflammatory medium (interleukin-1β, interferon-γ, interferon-α, tumor necrosis factor-α), TLR expression profiles were generated (DPSCs and DPSCs-i).ResultsDPSCs showed all characteristics of stem/progenitor cells. In basic medium DPSCs expressed TLRs 1–10 in different quantities. The inflammatory medium upregulated the expression of TLRs 2, 3, 4, 5, and 8, downregulated TLRs 1, 7, 9, and 10, and abolished TLR6.ConclusionsThe current study describes for the first time the distinctive TLR expression profile of DPSCs in uninflamed and inflamed conditions.