Synergistic proinflammatory interactions of microbial toxins and structural components characteristic to...

Area of Science:

• Environmental microbiology
• Immunology
• Toxicology

Background:

• Indoor environments harbor complex mixtures of microbial agents.
• Microbial toxins and structural components are key players in indoor air quality and health.
• Understanding synergistic effects is crucial for assessing health risks.

Purpose of the Study:

• To investigate the proinflammatory interactions between microbial toxins and structural components.
• To determine the impact of co-exposure on macrophage responses.
• To assess cellular damage and inflammatory gene expression.

Main Methods:

• Human THP-1 monocytic cells were exposed to microbial toxins (emodin, enniatin B, physcion, sterigmatocystin, valinomycin) alone and with bacterial lipopolysaccharide (LPS) or fungal β-glucan.
• Messenger RNA (mRNA) and protein levels of proinflammatory cytokines (TNFα, IL-1β) were measured using RT-qPCR and ELISA.
• Mitochondrial damage and autophagocytosis were assessed.

Main Results:

• Low-dose co-exposure of toxins with LPS or β-glucan synergistically increased proinflammatory cytokine expression (TNFα, IL-1β) at both mRNA and protein levels.
• Co-exposure with β-glucan consistently upregulated inflammation-related genes, while LPS showed some inhibitory effects.
• Combined exposure induced mitochondrial damage and autophagocytosis.

Conclusions:

• Microbial toxins and structural components from environments like moisture-damaged buildings can cause significant synergistic proinflammatory interactions.
• These synergistic effects occur even at low exposure levels.
• The findings highlight the complex interplay of indoor microbes in triggering inflammatory responses and cellular damage.