Puwainaphycins (PUW) and minutissamides (MIN) are cyanobacterial lipopeptides found in various cyanobacterial species. The first possible target of human exposure to them is intestinal epithelium but effect of PUW/MIN on enterocytes is not known at all. Using differentiated Caco-2 cells, PUW F was found to be cytotoxic from 5 µM concentration based on lactate dehydrogenase release assay and total protein concentration. However, it is also able to induce production of interleukin 8 in non-cytotoxic concentrations 1 and 2.5 µM detected by ELISA. Effects of MIN A and C were similar but less pronounced compared to PUW F. On the other hand, MIN D was the least toxic compound with no significant pro-inflammatory effects. Surprisingly, pro-inflammatory activation of the cells by PUW F and MIN C resulted in an increase in tight junction (TJ) protein claudin 4 expression determined by western blot analysis and confirmed by confocal microscopy. Furthermore, decrease in expression of zonula occludens 3, another TJ protein, was observed after the exposure to PUW F. Taken together, these cytotoxic lipopeptides, especially PUW F, are to be studied more deeply due to their capability to activate and/or deregulate human enterocytes in low concentrations.

Puwainaphycins（PUW）和Minutissamides（MIN）是在各种蓝细菌物种中发现的蓝细菌脂肽。人类接触它们的第一个可能靶标是肠上皮，但PUW / MIN对肠上皮细胞的作用完全未知。根据乳酸脱氢酶释放试验和总蛋白浓度，使用分化的Caco-2细胞，从5 µM浓度发现PUW F具有细胞毒性。但是，它也能够以ELISA检测到的非细胞毒性浓度1和2.5 µM诱导白介素8的产生。MIN A和C的作用与PUW F相似，但效果较差。另一方面，MIN D是毒性最低的化合物，无明显的促炎作用。出奇，PUW F和MIN C对细胞的促炎性激活导致紧密连接（TJ）蛋白claudin 4表达增加，该蛋白通过Western印迹分析确定并通过共聚焦显微镜确认。此外，在暴露于PUW F后，观察到另一种TJ蛋白zonula occludens 3的表达下降。这些细胞毒性脂肽，尤其是PUW F，由于其激活和/或失调的能力，合起来将被更深入地研究。低浓度的人类肠上皮细胞。