Pulp fibroblasts synthesize functional complement proteins involved in initiating dentin-pulp regeneration

Area of Science:

• Immunology
• Regenerative Medicine
• Oral Biology

Background:

• The complement system is crucial for immune surveillance and tissue repair.
• While the liver is the primary site of complement protein synthesis, local production is vital for tissue-specific responses.
• Dentin-pulp regeneration is a localized process, suggesting a role for local immune factors.

Purpose of the Study:

• To investigate the activation and role of the local complement system in dental pulp regeneration.
• To determine if dental pulp cells can synthesize complement proteins.
• To elucidate the mechanism by which complement activation influences pulp progenitor cell recruitment.

Main Methods:

• Analysis of complement activation markers (C5b-9) and bacterial presence (Gram staining) in carious human teeth.
• RT-PCR to assess complement protein gene expression in cultured human pulp fibroblasts stimulated with lipoteichoic acid.
• In vitro experiments to measure C5b-9 and C5a production by fibroblasts.
• Cell migration assays using a C5a receptor antagonist (W54011) to assess progenitor cell recruitment.

Main Results:

• Complement activation correlated with Gram-positive bacteria in carious teeth.
• Human pulp fibroblasts stimulated with lipoteichoic acid produced all necessary complement proteins, leading to C5b-9 and C5a formation independently of plasma.
• C5a generated by pulp fibroblasts specifically induced pulp progenitor cell migration.

Conclusions:

• Human pulp fibroblasts are the first identified non-immune cells capable of synthesizing the complete complement system.
• Fibroblast-derived complement activation plays a significant role in recruiting pulp progenitor cells for dentin-pulp regeneration.
• Targeting pulp fibroblasts and complement activation presents a potential therapeutic strategy for enhancing dental tissue regeneration.