In vitro characterization of the immunotoxic potential of several perfluorinated compounds (PFCs)
Emanuela Corsini1, Enrico Sangiovanni, Anna Avogadro
1Laboratory of Toxicology, Department of Pharmacological Sciences, Università degli Studi di Milano, Via Balzaretti 9, 20133 Milano, Italy. emanuela.corsini@unimi.it
Abstract:
We have previously shown that PFOA and PFOS directly suppress cytokine secretion in immune cells, with different mechanisms of action. In particular, we have demonstrated a role for PPAR-α in PFOA-induced immunotoxicity, and that PFOS has an inhibitory effect on LPS-induced I-κB degradation. These studies investigate the immunomodulatory effects of four other PFCs, namely PFBS, PFOSA, PFDA, and fluorotelomer using in vitro assays. The release of the pro-inflammatory cytokines IL-6 and TNF-α was evaluated in lipolysaccharide (LPS)-stimulated human peripheral blood leukocytes (hPBL) and in the human promyelocytic cell line THP-1, while the release of IL-10 and IFN-γ was evaluated in phytohemagglutinin (PHA)-stimulated hPBL. All PFCs suppressed LPS-induced TNF-α production in hPBL and THP-1 cells, while IL-6 production was suppressed by PFOSA, PFOS, PFDA and fluorotelomer. PFBS, PFOSA, PFOS, PFDA and fluorotelomer inhibited PHA-induced IL-10 release, while IFN-γ secretion was affected by PFOSA, PFOS, PFDA and fluorotelomer. Leukocytes obtained from female donors appear to be more sensitive to the in vitro immunotoxic effects of PFCs when their responses are compared to the results obtained using leukocytes from male donors. Mechanistic investigations demonstrated that inhibition of TNF-α release in THP-1 cells occurred at the transcriptional level. All PFCs, including PFOA and PFOS, decreased LPS-induced NF-κB activation. With the exception of PFOA, none of the PFCs tested was able to activate PPARα driven transcription in transiently transfected THP-1 cells, excluding a role for PPARα in the immunomodulation observed. PFBS and PFDA prevented LPS-induced I-κB degradation. Overall, these studies suggest that PFCs affect NF-κB activation, which directly suppresses cytokine secretion by immune cells. Our results indicate that PFOA is the least active of the PFCs examined followed by PFBS, PFDA, PFOS, PFOSA and fluorotelomer.
Insights
Per- and polyfluoroalkyl substances (PFCs) suppress immune cell cytokine secretion by affecting NF-κB activation. Fluorotelomer and PFOSA were most potent, while PFOA was least active among the tested PFCs.
Area of Science:
- Environmental toxicology
- Immunology
- Cell biology
Background:
- Per- and polyfluoroalkyl substances (PFCs) are widely used chemicals with known immunotoxic effects.
- Previous studies demonstrated PFOA and PFOS suppress cytokine secretion via distinct mechanisms, involving PPAR-α and I-κB degradation respectively.
Purpose of the Study:
- To investigate the immunomodulatory effects of four additional PFCs: PFBS, PFOSA, PFDA, and fluorotelomer.
- To elucidate the mechanisms underlying PFC-induced immunotoxicity, focusing on NF-κB activation and cytokine secretion.
Main Methods:
- In vitro assays using human peripheral blood leukocytes (hPBL) and THP-1 cells.
- Stimulation with lipopolysaccharide (LPS) or phytohemagglutinin (PHA) to assess cytokine release (IL-6, TNF-α, IL-10, IFN-γ).
- Mechanistic studies included NF-κB activation assays, PPARα-driven transcription assays, and I-κB degradation analysis.
Main Results:
- All tested PFCs suppressed LPS-induced TNF-α production. PFOSA, PFOS, PFDA, and fluorotelomer suppressed IL-6, IL-10, and IFN-γ release.
- PFCs inhibited LPS-induced NF-κB activation; PFBS and PFDA prevented I-κB degradation.
- Female donor leukocytes showed higher sensitivity to PFC immunotoxicity.
- PFOA was the least immunotoxic, followed by PFBS, PFDA, PFOS, PFOSA, and fluorotelomer.
Conclusions:
- PFCs exert immunomodulatory effects primarily by inhibiting NF-κB activation, leading to suppressed cytokine secretion.
- The potency of immunotoxicity varies among PFCs, with fluorotelomer and PFOSA being the most potent.
- Sex differences in immune cell sensitivity to PFCs warrant further investigation.
