Study Finds PFOSA Can Suppress Immune Function in Developing Zebrafish (Danio rerio)
The Stockholm Convention has labeled PFOS a “persistent organic pollutant” due to its long-enduring prevalence, negative toxicological effects, and ability to bioaccumulate in living things. Concerns about PFOSA have been raised due to its similarity to PFOS, its ability to metabolize into PFOS, and its persistent use today
What are forever chemicals and PFOSA?
A forever chemical is a name given to various anthropogenic compounds that can resist breaking down, some of which exceed a century under ambient conditions. A class of synthetic forever chemicals known as perfluorinated compounds, or PFCs, are commonly used in non-stick cookware, paints, waterproofing for clothes, stain repellents, fire suppressants, semiconductors, and even metal plating.
Some of these forever chemicals, such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), were phased out of production in the early 2000s, due to their negative environmental effects. However, one of their related compounds, perfluorooctanesulfonamide (PFOSA), is still widely used today in industrial processes. PFOSA’s impact on the environment and wildlife is currently not well understood.
Study Setup
To better understand PFOSA and its toxic effects on aquatic organisms, the immune function of early-life stage zebrafish exposed to concentrations of PFOSA found in the environment was measured, characterizing the toxic mechanism in which PFOSA regulates immune responses.
Zebrafish embryos were exposed to various concentrations of PFOS or PFOSA for five days. Zebrafish larvae were then collected following a five-day treatment to assess toxicity using a variety of endpoints. The concentration of PFOSA and PFOS used in exposures were confirmed with chemistry, in addition to concentrations accumulated in fish tissues, using high-performance liquid chromatography-tandem mass spectrometry.
A series of tests used to determine the impact of PFOS and PFOSA on zebrafish immune function at varied concentrations included their antibacterial response impact, survival rate, immune cell count, gene expression, protein levels of immune function indicators, and molecular docking.
Generalized Results
In this study, it was found that exposure to PFOSA dysregulates a series of immune-related indicators, immune cell numbers, and overall antibacterial ability in early-life stage fish. Additionally, the team characterized the mechanism of action which was not well understood previously.
The mechanism for PFOSA’s effects was found through the NF -κB pathway, which plays a major role in regulating inflammation, as well as innate and adaptive immune responses. By using morpholino knock downs, they were able to identify the cause of PFOSA’s effects on immune health. The resulting reduction in the antibacterial ability of the fish allowed for more bacterial adhesion, causing a higher mortality rate, and reduced levels of biocidal protein lysozymes.
Impacts on the immune function were found to cause a decrease in immune cell count, disruptions in inflammatory markers, and immune indicators. Overall, the negative effects of PFOSA generally increased in severity as the exposure concentration of PFOSA increased. The major takeaway is that PFOSA itself can cause immune dysfunction in zebrafish and uses the NF-κB pathway as the mechanism for PFOSA’s negative immune effects.
There is still much to learn on this topic
PFOSA is still widely used in many everyday products today and could be causing an impact on the environment. The findings in the study provide data and a mechanism to support a possible ecological risk tied to PFOSA itself. However, its effects on other organisms besides zebrafish are not well understood, and neither are the impacts of long-term exposure.
This is why further research on PFOSA, specifically, is needed to better understand the uniqueness of this compound and its similarities to PFOS and other forever chemicals. Researchers can use this data to help mitigate potential environmental hazards and to manage natural resources.
REFRENCES
Honghong Chen, Yao Zou, Xinyuan Kang, Ge Yang, Xin Yang, Yingying Yao, Jason T. Magnuson, Xinde Cao, Wenhui Qiu, Elvis Genbo Xu, and Chunmiao Zheng, 2024, Perfluorooctane Sulfonamide Induced Autotoxic Effects on the Zebrafish Immune System: Environmental Science & Technology, v. 58, no. 30, p. 13205-13216.
The Stockholm Convention has labeled PFOS a “persistent organic pollutant” due to its long-enduring prevalence, negative toxicological effects, and ability to bioaccumulate in living things. Concerns about PFOSA have been raised due to its similarity to PFOS, its ability to metabolize into PFOS, and its persistent use today
What are forever chemicals and PFOSA?
A forever chemical is a name given to various anthropogenic compounds that can resist breaking down, some of which exceed a century under ambient conditions. A class of synthetic forever chemicals known as perfluorinated compounds, or PFCs, are commonly used in non-stick cookware, paints, waterproofing for clothes, stain repellents, fire suppressants, semiconductors, and even metal plating.
Some of these forever chemicals, such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), were phased out of production in the early 2000s, due to their negative environmental effects. However, one of their related compounds, perfluorooctanesulfonamide (PFOSA), is still widely used today in industrial processes. PFOSA’s impact on the environment and wildlife is currently not well understood.
Study Setup
To better understand PFOSA and its toxic effects on aquatic organisms, the immune function of early-life stage zebrafish exposed to concentrations of PFOSA found in the environment was measured, characterizing the toxic mechanism in which PFOSA regulates immune responses.
Zebrafish embryos were exposed to various concentrations of PFOS or PFOSA for five days. Zebrafish larvae were then collected following a five-day treatment to assess toxicity using a variety of endpoints. The concentration of PFOSA and PFOS used in exposures were confirmed with chemistry, in addition to concentrations accumulated in fish tissues, using high-performance liquid chromatography-tandem mass spectrometry.
A series of tests used to determine the impact of PFOS and PFOSA on zebrafish immune function at varied concentrations included their antibacterial response impact, survival rate, immune cell count, gene expression, protein levels of immune function indicators, and molecular docking.
Generalized Results
In this study, it was found that exposure to PFOSA dysregulates a series of immune-related indicators, immune cell numbers, and overall antibacterial ability in early-life stage fish. Additionally, the team characterized the mechanism of action which was not well understood previously.
The mechanism for PFOSA’s effects was found through the NF -κB pathway, which plays a major role in regulating inflammation, as well as innate and adaptive immune responses. By using morpholino knock downs, they were able to identify the cause of PFOSA’s effects on immune health. The resulting reduction in the antibacterial ability of the fish allowed for more bacterial adhesion, causing a higher mortality rate, and reduced levels of biocidal protein lysozymes.
Impacts on the immune function were found to cause a decrease in immune cell count, disruptions in inflammatory markers, and immune indicators. Overall, the negative effects of PFOSA generally increased in severity as the exposure concentration of PFOSA increased. The major takeaway is that PFOSA itself can cause immune dysfunction in zebrafish and uses the NF-κB pathway as the mechanism for PFOSA’s negative immune effects.
There is still much to learn on this topic
PFOSA is still widely used in many everyday products today and could be causing an impact on the environment. The findings in the study provide data and a mechanism to support a possible ecological risk tied to PFOSA itself. However, its effects on other organisms besides zebrafish are not well understood, and neither are the impacts of long-term exposure.
This is why further research on PFOSA, specifically, is needed to better understand the uniqueness of this compound and its similarities to PFOS and other forever chemicals. Researchers can use this data to help mitigate potential environmental hazards and to manage natural resources.
REFRENCES
Honghong Chen, Yao Zou, Xinyuan Kang, Ge Yang, Xin Yang, Yingying Yao, Jason T. Magnuson, Xinde Cao, Wenhui Qiu, Elvis Genbo Xu, and Chunmiao Zheng, 2024, Perfluorooctane Sulfonamide Induced Autotoxic Effects on the Zebrafish Immune System: Environmental Science & Technology, v. 58, no. 30, p. 13205-13216.