Institute of Biochemistry, Life Sciences Centre, Vilnius University, Saulėtekio al. 7, LT-10257, Vilnius, Lithuania.
Institute of Biotechnology, Life Sciences Centre, Vilnius University, Saulėtekio al. 7, LT-10257, Vilnius, Lithuania.
Sci Rep. 2019 Jul 23;9(1):10606. doi: 10.1038/s41598-019-47043-5.
The pore-forming toxins, inerolysin (INY) and vaginolysin (VLY), produced by vaginal bacteria Lactobacillus iners and Gardnerella vaginalis were studied using the artificial cholesterol-rich tethered bilayer membranes (tBLMs) by electrochemical techniques. The electrochemical impedance spectroscopy (EIS) of tBLMs attested for the toxin-induced impairment of the integrity of phospholipid membranes. This observation was in line with the atomic force microscopy data demonstrating formation of oligomeric protein assemblies in tBLMs. These assemblies exhibited different morphologies: VLY mostly formed complete rings, whereas INY produced arciform structures. We found that both EIS (membrane damage) and the surface plasmon resonance (protein binding) data obtained on tBLMs are in-line with the data obtained in human cell lysis experiments. EIS, however, is capable of capturing effects inaccessible for biological activity assays. Specifically, we found that the INY-induced damage of tBLMs is nearly a linear function of membrane cholesterol content, whereas VLY triggered significant damage only at high (50 mol%) cholesterol concentrations. The observed differences of INY and VLY activities on phospholipid membranes might have clinical importance: both toxin-producing bacteria have been found in healthy vagina and dysbiosis, suggesting the need for adaptation at different vaginal conditions. Our results broaden the possibilities of application of tBLMs in medical diagnostics.
通过电化学技术，研究了阴道细菌惰性乳杆菌和阴道加德纳菌产生的孔形成毒素内溶素（INY）和阴道溶素（VLY）在人工富含胆固醇的固定双层膜（tBLM）上的作用。tBLM 的电化学阻抗谱（EIS）证明了毒素诱导的磷脂膜完整性受损。这一观察结果与原子力显微镜数据一致，表明在 tBLM 中形成了寡聚蛋白组装体。这些组装体表现出不同的形态：VLY 主要形成完整的环，而 INY 则产生弧形结构。我们发现，tBLM 上获得的 EIS（膜损伤）和表面等离子体共振（蛋白质结合）数据与在人细胞裂解实验中获得的数据一致。然而，EIS 能够捕捉到生物学活性测定无法获得的影响。具体来说，我们发现 INY 诱导的 tBLM 损伤几乎是膜胆固醇含量的线性函数，而 VLY 仅在高（50 mol%）胆固醇浓度下才引发显著损伤。INY 和 VLY 在磷脂膜上活性的差异可能具有临床意义：这两种产毒细菌都在健康阴道和微生态失调中被发现，这表明需要适应不同的阴道条件。我们的研究结果拓宽了 tBLM 在医学诊断中的应用可能性。
