Effects of green tea on miRNA and microbiome of oral epithelium

Area of Science:

• Oral oncology
• Microbiome research
• Nutritional biochemistry

Background:

• Green tea (GT) extracts show promise in preventing cancers in rodent models, but human evidence is inconsistent.
• Understanding variable human responses to GT is crucial for assessing its role in oral cancer prevention.
• Smokers, a high-risk group for oral cancer, were studied to investigate GT's effects.

Purpose of the Study:

• To investigate the variable effects of green tea consumption on oral epithelium and microbiota in human smokers.
• To identify potential mechanisms behind green tea's inconsistent effects on oral cancer risk.
• To analyze changes in miRNA expression and bacterial populations following GT exposure.

Main Methods:

• Collected lingual epithelial RNA and oral microbiota samples from tobacco smokers before and after 4 weeks of GT extract consumption.
• Analyzed miRNA expression patterns, focusing on coordinated changes in paired miRNAs.
• Assessed shifts in the relative abundance of oral bacterial genera using microbiome analysis.

Main Results:

• Green tea consumption showed inconsistent effects on overall miRNA expression in the oral epithelium.
• Coordinated expression analysis identified specific miRNAs (e.g., miR-181a-5p, miR-301a-3p) affected by GT exposure.
• Significant shifts were observed in the relative abundance of oral bacteria, including Streptococcus and Staphylococcus genera.

Conclusions:

• Green tea consumption consistently alters the human oral microbiome, potentially influencing carcinogenesis.
• Individual variability in green tea's effect on oral epithelial miRNA expression was observed in humans.
• The findings suggest that changes in oral bacteria may be a more consistent indicator of GT's impact than epithelial miRNA expression.