Study Reveals Environmental Contaminant 6-PPDQ Disrupts Citric Acid Cycle in C. elegans

Researchers have uncovered how 6-PPD quinone (6-PPDQ), a contaminant from tire antioxidant 6PPD, affects the citric acid cycle in Caenorhabditis elegans at concentrations found in the environment. The study, published in Environmental Chemistry and Ecotoxicology, shows a notable decrease in citric acid cycle intermediates and key enzyme gene expressions due to 6-PPDQ exposure, pointing to its potential hazard to metabolic processes.

The citric acid cycle is vital for cellular metabolism, connecting the breakdown of carbohydrates, fats, and proteins. The research found that 6-PPDQ at 0.1–10 μg/L reduced levels of crucial intermediates like citric acid and α-ketoglutarate, alongside suppressing genes essential for the cycle's function. This disruption was linked to decreased acetyl CoA and pyruvate, fundamental for the cycle's operation, with specific genes involved in their synthesis also affected.

Further findings indicated that 6-PPDQ exposure led to mitochondrial dysfunction, evidenced by altered oxygen consumption and ATP levels. However, sodium pyruvate treatment showed potential in mitigating these toxic effects, offering a possible avenue for addressing 6-PPDQ's impact. The study underscores the need for further investigation into 6-PPDQ's environmental and health implications, given its widespread presence and metabolic disruption capabilities.