College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan 430074, China.
Toxins (Basel). 2024 Mar 13;16(3):145. doi: 10.3390/toxins16030145.
Microcystin-LR (MC-LR) is a secondary metabolite produced by cyanobacteria, globally renowned for its potent hepatotoxicity. However, an increasing body of research suggests that it also exhibits pronounced neurotoxicity. PP2A is a fundamental intracellular phosphatase that plays a pivotal role in cell development and survival. Although extensive research has focused on the binding of MC-LR to the C subunit of PP2A, few studies have explored the key amino acid sites that can prevent the binding of MC-LR to PP2A-C. Due to the advantages of (), such as ease of genetic editing and a short lifespan, we exposed nematodes to MC-LR in a manner that simulated natural exposure conditions based on MC-LR concentrations in natural water bodies (immersion exposure). Our findings demonstrate that MC-LR exerts comprehensive toxicity on nematodes, including reducing lifespan, impairing reproductive capabilities, and diminishing sensory functions. Notably, and for the first time, we observed that MC-LR neurotoxic effects can persist up to the F3 generation, highlighting the significant threat that MC-LR poses to biological populations in natural environments. Furthermore, we identified two amino acid sites (L252 and C278) in PP2A-C through mutations that prevented MC-LR binding without affecting PP2A activity. This discovery was robustly validated through behavioral studies and neuronal calcium imaging using nematodes. In conclusion, we identified two crucial amino acid sites that could prevent MC-LR from binding to PP2A-C, which holds great significance for the future development of MC-LR detoxification drugs.
微囊藻毒素-LR（MC-LR）是一种由蓝藻产生的次生代谢产物，以其强烈的肝毒性而闻名于世。然而，越来越多的研究表明，它还表现出明显的神经毒性。PP2A 是一种基本的细胞内磷酸酶，在细胞发育和存活中起着关键作用。尽管广泛的研究集中在 MC-LR 与 PP2A 的 C 亚基结合上，但很少有研究探讨可以阻止 MC-LR 与 PP2A-C 结合的关键氨基酸位点。由于（）的优势，如易于遗传编辑和寿命短，我们以模拟自然暴露条件的方式使线虫暴露于 MC-LR 中，这是基于天然水体中 MC-LR 浓度进行的（浸泡暴露）。我们的研究结果表明，MC-LR 对线虫具有全面的毒性，包括缩短寿命、损害生殖能力和降低感觉功能。值得注意的是，我们首次观察到 MC-LR 的神经毒性作用可以持续到 F3 代，突出表明 MC-LR 对自然环境中生物种群构成的重大威胁。此外，我们通过突变鉴定了 PP2A-C 中的两个氨基酸位点（L252 和 C278），这些突变可以防止 MC-LR 结合而不影响 PP2A 活性。这一发现通过使用线虫进行的行为研究和神经元钙成像得到了有力验证。总之，我们确定了两个可以阻止 MC-LR 与 PP2A-C 结合的关键氨基酸位点，这对未来开发 MC-LR 解毒药物具有重要意义。
