MicroRNAs Regulate Cytokine Responses in Gingival Epithelial Cells

Area of Science:

• Oral biology
• Molecular biology
• Immunology

Background:

• MicroRNAs (miRNAs) are crucial regulators of biological processes.
• Periodontal disease pathogenesis may involve specific miRNAs.
• Previous studies showed differential miRNA expression in healthy versus periodontitis tissues.

Purpose of the Study:

• To investigate the role of specific miRNAs in human gingival keratinocytes' response to periodontal pathogens.
• To understand how miRNA dysregulation impacts inflammatory cytokine production and immune cell recruitment.

Main Methods:

• Established stable knockdown (KD) cell lines for five epithelium-expressed miRNAs (miR-126, miR-141, miR-155, miR-210, miR-1246).
• Infected KD cells with periodontal pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans).
• Assessed gene and protein expression of inflammatory markers (IL-8, CXCL1) using qPCR, ELISA, and Western blot; analyzed NF-κB pathway activity and neutrophil chemotaxis.

Main Results:

• miR-126 KD cells exhibited reduced IL-8 and CXCL1 expression upon bacterial challenge.
• miR-155 and miR-210 KD cells showed increased IL-8 and CXCL1 expression.
• NF-κB pathway activity was altered in KD cells.
• miR-126 knockdown impaired neutrophil chemotaxis.

Conclusions:

• Specific miRNAs, notably miR-126, miR-155, and miR-210, significantly modulate inflammatory cytokine expression in gingival epithelial cells in response to microbial infection.
• These miRNAs play a critical role in regulating the innate immune response in the context of periodontal disease.
• Findings highlight potential miRNA-based therapeutic targets for periodontal conditions.