A Comparative Review of the Effect of Microcystin-LR on the Proteome

Cyanobacterial toxins are a growing threat to human and animal welfare in many parts of the world. Microcystin-LR is the most widely studied of the cyanotoxins and has been implicated with hepatotoxicity, neuropathology, and genotoxicity. Numerous studies investigated the effect of microcystin-LR exposure on the proteome using various animal models, and together they form a large database of potential protein biomarkers. However, it is extremely difficult to establish which proteins are specifically affected by microcystin-LR, and which represent a more general toxin response. The goal of this review was to filter out inconsistently reported protein abundancy changes after microcystin-LR exposure. We explored online search engines for studies investigating the effect of microcystin-LR toxicity on the proteome. The selected studies were examined to find overlapping protein abundancy changes. The protein names, their synonyms, and relevant orthologues were used as search terms. This review has produced, for the first time, a comprehensive list of proteins whose abundancies changed in at least two proteomic studies investigating microcystin-LR toxicity in rodents and zebrafish. Proteins involved in oxidoreductase activity and cytoskeletal processes are persistently affected by microcystin-LR exposure. Several oxidative stress markers are consistently altered across multiple proteomic studies, which correlates with findings from epidemiological studies that linked chronic microcystin exposure to increased incidences of liver and colorectal cancer. This study unveils which proteins' abundancies are consistently altered after microcystin-LR exposure and opens new doors to understanding the mechanisms behind microcystin-LR toxicity.