Dos Santos A G, Marquês J T, Carreira A C, Castro I R, Viana A S, Mingeot-Leclercq M-P, de Almeida R F M, Silva L C
iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
Phys Chem Chem Phys. 2017 Nov 15;19(44):30078-30088. doi: 10.1039/c7cp05353c.
Nystatin (Nys) is a pore forming broad-spectrum and efficient antifungal drug with significant toxicity in mammalian organisms. In order to develop a non-toxic and more effective Nys formulation, its molecular mechanism of action at the cell membrane needs to be better understood. It is widely accepted that Nys activity and toxicity depend on the presence and type of membrane sterols. Taking advantage of multiple biophysical methodologies, we now show that the formation and stabilization of Nys aqueous pores, which are associated with Nys cytotoxicity, occur in the absence of membrane sterols. Our results suggest that the Nys mechanism of action is driven by the presence of highly ordered membrane domains capable of stabilizing the Nys oligomers. Moreover, Nys pore formation is accompanied by strong Nys-induced membrane reorganization that depends on membrane lipid composition and seems to underlie the Nys cytotoxic effect. Accordingly, in membranes enriched in a gel-phase forming phospholipid, Nys incorporates within the phospholipid-enriched gel domains, where it forms pores able to expand the gel domains. In contrast, in membranes enriched in gel domain forming sphingolipids, Nys-induced pore formation occurs through the destabilization of the gel phase. These results show that the Nys mechanism of action is complex and not only dependent on membrane sterols, and provide further insight into the molecular details governing Nys activity and toxicity.
制霉菌素（Nys）是一种能形成孔道的广谱高效抗真菌药物，在哺乳动物体内具有显著毒性。为了开发一种无毒且更有效的制霉菌素制剂，需要更好地了解其在细胞膜上的分子作用机制。人们普遍认为制霉菌素的活性和毒性取决于膜甾醇的存在和类型。利用多种生物物理方法，我们现在表明，与制霉菌素细胞毒性相关的制霉菌素水性孔道的形成和稳定在没有膜甾醇的情况下也会发生。我们的结果表明，制霉菌素的作用机制是由能够稳定制霉菌素寡聚体的高度有序膜结构域的存在所驱动的。此外，制霉菌素孔道的形成伴随着强烈的制霉菌素诱导的膜重组，这取决于膜脂质组成，似乎是制霉菌素细胞毒性作用的基础。因此，在富含形成凝胶相磷脂的膜中，制霉菌素掺入富含磷脂的凝胶结构域内，在那里它形成能够扩展凝胶结构域的孔道。相反，在富含形成凝胶结构域鞘脂的膜中，制霉菌素诱导的孔道形成是通过凝胶相的不稳定而发生的。这些结果表明，制霉菌素的作用机制是复杂的，不仅依赖于膜甾醇，并为控制制霉菌素活性和毒性分子细节提供了进一步的见解。
