Institute of Biomedical and Oral Research (IBOR), Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
Int J Mol Sci. 2023 Mar 24;24(7):6177. doi: 10.3390/ijms24076177.
is a cariogenic bacterium in the oral cavity involved in plaque formation and dental caries. The endocannabinoid anandamide (AEA), a naturally occurring bioactive lipid, has been shown to have anti-bacterial and anti-biofilm activities against . We aimed here to study its effects on viability, biofilm formation and extracellular polysaccharide substance (EPS) production. were cultivated in the absence or presence of various concentrations of AEA, and the planktonic growth was followed by changes in optical density (OD) and colony-forming units (CFU). The resulting biofilms were examined by MTT metabolic assay, Crystal Violet (CV) staining, spinning disk confocal microscopy (SDCM) and high-resolution scanning electron microscopy (HR-SEM). The EPS production was determined by Congo Red and fluorescent dextran staining. Membrane potential and membrane permeability were determined by diethyloxacarbocyanine iodide (DiOC2(3)) and SYTO 9/propidium iodide (PI) staining, respectively, using flow cytometry. We observed that AEA was bactericidal to at 12.5 µg/mL and prevented biofilm formation at the same concentration. AEA reduced the biofilm thickness and biomass with concomitant reduction in total EPS production, although there was a net increase in EPS per bacterium. Preformed biofilms were significantly affected at 50 µg/mL AEA. We further show that AEA increased the membrane permeability and induced membrane hyperpolarization of these bacteria. AEA caused to become elongated at the minimum inhibitory concentration (MIC). Gene expression studies showed a significant increase in the cell division gene . The concentrations of AEA needed for the anti-bacterial effects were below the cytotoxic concentration for normal Vero epithelial cells. Altogether, our data show that AEA has anti-bacterial and anti-biofilm activities against and may have a potential role in preventing biofilms as a therapeutic measure.
是口腔中致龋的细菌，参与菌斑形成和龋齿。内源性大麻素大麻素（AEA），一种天然存在的生物活性脂质，已被证明具有抗细菌和抗生物膜活性。我们旨在研究其对的活力、生物膜形成和细胞外多糖物质（EPS）产生的影响。在不存在或存在不同浓度的 AEA 的情况下培养，通过光密度（OD）和菌落形成单位（CFU）的变化来跟踪浮游生物的生长。通过 MTT 代谢测定、结晶紫（CV）染色、旋转圆盘共聚焦显微镜（SDCM）和高分辨率扫描电子显微镜（HR-SEM）检查生成的生物膜。通过刚果红和荧光葡聚糖染色测定 EPS 产生。通过二乙氧基羰花青碘化物（DiOC2（3））和 SYTO 9/碘化丙啶（PI）染色，分别使用流式细胞术测定膜电位和膜通透性。我们观察到 AEA 在 12.5 µg/mL 时对具有杀菌作用，并在相同浓度下阻止生物膜形成。AEA 降低了生物膜厚度和生物量，同时减少了总 EPS 的产生，尽管每个细菌的 EPS 净增加。在 50 µg/mL AEA 时，预先形成的生物膜受到显著影响。我们进一步表明，AEA 增加了这些细菌的膜通透性并诱导膜超极化。AEA 在最小抑菌浓度（MIC）下使变为伸长形。基因表达研究表明细胞分裂基因显著增加。具有抗细菌作用的 AEA 浓度低于正常 Vero 上皮细胞的细胞毒性浓度。总之，我们的数据表明 AEA 对具有抗细菌和抗生物膜活性，并且作为一种治疗措施，可能在预防生物膜方面具有潜在作用。
