TLR4 mediates LPS-induced VEGF expression in odontoblasts

Area of Science:

• Oral biology
• Immunology
• Cellular signaling

Background:

• Gram-negative bacteria lipopolysaccharide (LPS) stimulates vascular endothelial growth factor (VEGF) in odontoblasts.
• The roles of CD14 and Toll-like receptor 4 (TLR4) in dental pulp cells' response to LPS are not well understood.

Purpose of the Study:

• To investigate the expression and function of CD14 and TLR4 in odontoblast-like cells and undifferentiated dental pulp cells.
• To determine the involvement of CD14 and TLR4 in LPS-induced VEGF expression in odontoblasts.

Main Methods:

• Immunohistochemistry and flow cytometry were used to detect CD14 and TLR4 expression in murine odontoblast-like cells (MDPC-23) and undifferentiated dental pulp cells (OD-21).
• Real-time PCR assessed CD14 and TLR4 upregulation following LPS exposure.
• Dominant-negative TLR4 (DN-mTLR4) transfection was employed to evaluate TLR4's functional role in LPS-induced VEGF expression.

Main Results:

• Murine odontoblast-like cells (MDPC-23) express CD14 and TLR4, while undifferentiated dental pulp cells (OD-21) show minimal expression.
• LPS exposure led to increased CD14 and TLR4 expression in MDPC-23 cells.
• Inhibition of TLR4 signaling using DN-mTLR4 prevented LPS-induced VEGF upregulation in MDPC-23 cells.

Conclusions:

• Odontoblast-like cells express CD14 and TLR4, key components of the LPS recognition system.
• Toll-like receptor 4 signaling is a significant mediator of lipopolysaccharide-induced vascular endothelial growth factor expression in odontoblasts.