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

Recent research has shed light on the detrimental effects of 6-PPD quinone (6-PPDQ), an environmental contaminant originating from tire antioxidants, on the citric acid cycle in Caenorhabditis elegans. Published in Environmental Chemistry and Ecotoxicology, the study conducted by Southeast University in China demonstrates how 6-PPDQ, at concentrations relevant to environmental exposure, significantly disrupts this vital metabolic pathway.

The citric acid cycle is fundamental for cellular metabolism, connecting the breakdown of carbohydrates, fats, and proteins to produce energy. The study found that 6-PPDQ exposure led to a marked reduction in key intermediates of the cycle, such as citric acid and α-ketoglutarate, by inhibiting the expression of genes responsible for their production. This disruption not only affects energy production but also the synthesis of essential biomolecules, posing a risk to organismal health.

Further investigations revealed that 6-PPDQ decreases acetyl CoA and pyruvate levels, crucial for initiating the citric acid cycle. The suppression of genes related to the pyruvate dehydrogenase complex, which facilitates acetyl CoA synthesis, underscores the compound's broad impact on metabolic processes. Additionally, the study noted mitochondrial dysfunction in exposed nematodes, characterized by altered oxygen consumption and reduced ATP levels, further emphasizing the toxic potential of 6-PPDQ.

Interestingly, the research also explored potential countermeasures, finding that sodium pyruvate treatment could mitigate some of the toxic effects of 6-PPDQ. This discovery opens avenues for future research into protective strategies against environmental contaminants. The findings underscore the urgent need for further studies to assess the full scope of 6-PPDQ's impact on ecosystems and human health, highlighting the compound's significance as an emerging environmental pollutant.