8:2 Fluorotelomer alcohol causes immunotoxicity and liver injury in adult male C57BL/6 mice

Developmental immunotoxicity of maternal exposure to yttrium nitrate on BALB/c offspring mice

Yttrium is a typical heavy rare earth element with widespread use in numerous sectors. Only one previous study has indicated that yttrium has the potential to cause developmental immunotoxicity (DIT). Therefore, there remains a paucity of evidence on the DIT of yttrium. This study aimed to explore the DIT of yttrium nitrate (YN) and the self-recovery of YN-induced DIT. Dams were treated with 0, 0.2, 2, and 20 mg/kg bw/day YN by gavage during gestation and lactation. No significant changes were found in innate immunity between the control and YN-treated groups in offspring. In female offspring at postnatal day 21 (PND21), YN markedly inhibited humoral and cellular immune responses, the proliferative capacity of splenic T lymphocytes, and the expression of costimulatory molecules in splenic lymphocytes. Moreover, the inhibitory effect on cellular immunity in female offspring persisted to PND42. Unlike females, YN exposure did not change the adaptive immune responses in male offspring. Overall, maternal exposure to YN showed a strong DIT to offspring, with the lowest effective dose of 0.2 mg/kg in the current study. The toxicity of cellular immunity could persist throughout development into adulthood. There were sex-specific differences in YN-induced DIT, with females being more vulnerable.

Application of the Key Characteristics of Carcinogens to Per and Polyfluoroalkyl Substances

Per- and polyfluoroalkyl substances (PFAS) constitute a large class of environmentally persistent chemicals used in industrial and consumer products. Human exposure to PFAS is extensive, and PFAS contamination has been reported in drinking water and food supplies as well as in the serum of nearly all people. The most well-studied member of the PFAS class, perfluorooctanoic acid (PFOA), induces tumors in animal bioassays and has been associated with elevated risk of cancer in human populations. GenX, one of the PFOA replacement chemicals, induces tumors in animal bioassays as well. Using the Key Characteristics of Carcinogens framework for cancer hazard identification, we considered the existing epidemiological, toxicological and mechanistic data for 26 different PFAS. We found strong evidence that multiple PFAS induce oxidative stress, are immunosuppressive, and modulate receptor-mediated effects. We also found suggestive evidence indicating that some PFAS can induce epigenetic alterations and influence cell proliferation. Experimental data indicate that PFAS are not genotoxic and generally do not undergo metabolic activation. Data are currently insufficient to assess whether any PFAS promote chronic inflammation, cellular immortalization or alter DNA repair. While more research is needed to address data gaps, evidence exists that several PFAS exhibit one or more of the key characteristics of carcinogens.

8:2 Fluorotelomer alcohol causes G1 cell cycle arrest and blocks granulocytic differentiation in HL-60 cells

Fluorotelomer alcohols (FTOHs) are fluorinated intermediates used in manufacturing specialty polymer and surfactants, with 8:2 FTOH the homologue of largest production. FTOHs were found to pose acute toxicity, hepatotoxicity, nephrotoxicity, developmental toxicity and endocrine-disrupting risks, whereas research regarding immunotoxicity and its underlying mechanism, especially on specific immune cells is limited. Here, we investigated the immunotoxicity of 8:2 FTOH on immature immune cells in an in vitro system. We observed that exposure of HL-60 cells, a human promyelocytic leukemic cell line, to 8:2 FTOH reduced cell viability in a dose- and time-dependent manner. In addition, 8:2 FTOH exposure caused G1 cell cycle arrest in HL-60 cells, while it showed no effect on apoptosis. Exposure to 8:2 FTOH inhibited the mRNA expression of cell cycle-related genes, including CCNA1, CCNA2, CCND1, and CCNE2. Moreover, exposure to 8:2 FTOH inhibited the mRNA expression of granulocytic differentiation-related genes of CD11b, CSF3R, PU.1, and C/EPBε in HL-60 cells . Furthermore, 8:2 FTOH exhibited no effect on intracellular ROS level, while hydralazine hydrochloride (Hyd), one reactive carbonyl species (RCS) scavenger, partially blocked 8:2 FTOH-caused cytotoxicity in HL-60 cells. Overall, the results obtained in the study show that 8:2 FTOH poses immunotoxicity in immature immune cells and RCS may partially underline its mechanism.