Brevetoxin PbTx2 Modulates Oxidative Stress and Inflammatory Response in an In Vitro Human Immune Cell Line

Area of Science:

• Environmental toxicology
• Immunology
• Cellular biology

Background:

• Brevetoxins (PbTx) are marine toxins known to negatively impact marine life and human health.
• Primary mechanisms of toxicity involve disruptions in immune cell function.

Purpose of the Study:

• To investigate the immunotoxic effects of sublethal concentrations of brevetoxin-2 (PbTx-2).
• To utilize the THP-1 human monocyte cell line as an in vitro model for assessing PbTx-2's impact on immune and oxidative responses.

Main Methods:

• Cell viability was assessed using the MTT assay to determine the IC50.
• Gene expression analysis was performed using quantitative PCR (qPCR).
• Antioxidant enzyme activities and reactive oxygen species (ROS) levels were measured.

Main Results:

• Sublethal PbTx-2 concentrations (2.8 and 5.6 µM) did not affect THP-1 cell viability at 4 and 8 hours.
• PbTx-2 exposure altered the expression of key inflammatory genes (IL-8, IL-1β, TNF-α) and antioxidant enzymes (catalase, glutathione reductase).
• Catalase and Cu/Zn-superoxide dismutase activities decreased, while ROS levels remained unchanged.

Conclusions:

• PbTx-2 modulates redox and inflammatory pathways in human monocytes even at non-cytotoxic concentrations.
• Sublethal brevetoxin exposure may have immunomodulatory consequences.
• Further research is required to understand the long-term effects of chronic low-level brevetoxin exposure on immune dysfunction and inflammatory diseases.