Effects of cylindrospermopsin on cultured immortalized human airway epithelial cells

• Published in: Chemosphere (Oxford) Vol. 220; pp. 620 - 628
• Main Authors: Kubickova, Barbara, Laboha, Petra, Hildebrandt, Jan-Peter, Hilscherová, Klara, Babica, Pavel
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2019
• Subjects: Cyanobacteria; Cyanotoxin; HBE; Inhalation toxicity; MAPK; Inhalation toxicity; HBE; MAPK; Cyanobacteria; Cyanotoxin
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2018.12.157

Anthropogenic eutrophication of freshwater bodies increases the occurrence of toxic cyanobacterial blooms. The cyanobacterial toxin cylindrospermopsin (CYN) is detected in the environment with increasing frequency, driving the scientific effort to assess emerging health risks from CYN-producing blooms. Oral exposure to CYN results primarily in hepatotoxicity. Nevertheless, extrahepatic manifestations of CYN toxicity have been reported. Furthermore, cyanotoxins have been detected in aerosols and dust particles, suggesting potential toxic effects in the respiratory tract. To assess the susceptibility of airway epithelia towards cyanotoxins, monolayers of immortalized human bronchial epithelial cells HBE1 and 16HBE14o- were exposed to a concentration range of 0.1–10 μM CYN. Cytotoxic endpoints were assessed as morphologic alterations, resazurin reduction capacity, esterase activity, neutral red uptake, and by impedimetric real-time cell analysis. Depending on the endpoint assessed, EC50 values ranged between 0.7 and 1.8 μM (HBE1) and 1.6–4.8 μM (16HBE14o-). To evaluate alterations of other cellular events by subcytotoxic concentration of CYN (1 μM), phosphorylation of mitogen-activated protein kinases ERK and p38 was determined. Only a slight increase in p38 phosphorylation was induced by CYN in HBE1 cell line after 48 h, while activities of both ERK1/2 and p38 gradually and significantly increased in 16HBE14o- cells during 8–48 h exposure. This study suggests possible hazards of inhalation CYN exposures, which may severely impact the integrity of airway epithelia and epithelial cell signaling. Further research of CYN-induced toxicity and underlying mechanisms is needed, as well as more data on environmental concentrations of cyanotoxins in aerosols for exposure assessment. [Display omitted] •The respiratory tract is a potential target of cylindrospermopsin toxicity.•Toxic effects observed at environmentally relevant concentrations.•Altered MAPK p38 phosphorylation upon ˃24 h exposure indicates inflammation.•The barrier function of airway epithelia was impaired.