Graduate School of Biotechnology, Kyung Hee University, Seocheon, Giheung, Yongin, Gyeonggi-do, Republic of Korea.
College of Life Science, Kyung Hee University, Seocheon, Giheung, Yongin, Gyeonggi-do, Republic of Korea.
PLoS One. 2021 Oct 6;16(10):e0258108. doi: 10.1371/journal.pone.0258108. eCollection 2021.
Candida is an opportunistic pathogen and a common cause of fungal infections worldwide. Anti-fungal use against Candida infections has resulted in the appearance of resistant strains. The limited choice of anti-fungal therapy means alternative strategies are needed to control fungal infectious diseases. The aim of this study was to evaluate the inhibition of Candida biofilm formation by Hedera rhombea (Korean name: songak) extract. Biofilm formation was assessed using the crystal violet assay which showed a dose dependent reduction in the presence of extract with the biofilm formation inhibitory concentration of C. albicans (IC50 = 12.5μg/ml), C. tropicalis var. tropicalis (IC50 = 25μg/ml), C. parapsilosis var. parapsilosis (IC50 = 6.25μg/ml), C. glabrata (IC50 = 6.25μg/ml), C. tropicalis (IC50 = 12.5μg/ml), and C. parapsilosis (IC50 = 12.5μg/ml) without directly reducing Candida growth. Treatment with 6.25μg/mL of extract increased the antifungal susceptibility to miconazole from 32% decreasing of fungal growth to 98.8% of that based on the fungal growth assay. Treatment of extract dose-dependently reduced the dimorphic transition of Candida based on the dimorphic transition assay and treatment of 3.125μg/mL of extract completely blocked the adherence of Candida to the HaCaT cells. To know the molecular mechanisms of biofilm formation inhibition by extract, qRT-PCR analysis was done, and the extract was found to dose dependently reduce the expression of hyphal-associated genes (ALS3, ECE1, HWP1, PGA50, and PBR1), extracellular matrix genes (GSC1, ZAP1, ADH5, and CSH1), Ras1-cAMP-PKA pathway genes (CYR1, EFG1, and RAS1), Cph2-Tec1 pathway gene (TEC1) and MAP kinases pathway gene (HST7). In this study, Hedera rhombea extract showed inhibition of fungal biofilm formation, activation of antifungal susceptibility, and reduction of infection. These results suggest that fungal biofilm formation is good screen for developing the antifungal adjuvant and Hedera rhombea extract should be a good candidate against biofilm-related fungal infection.
假丝酵母是一种机会性病原体，也是全球真菌感染的常见原因。抗真菌药物治疗假丝酵母感染导致了耐药菌株的出现。抗真菌治疗选择有限，这意味着需要寻找替代策略来控制真菌性传染病。本研究旨在评估贯叶连翘（韩国名：songak）提取物对假丝酵母生物膜形成的抑制作用。通过结晶紫测定法评估生物膜形成情况，结果显示提取物的存在呈剂量依赖性降低，白假丝酵母（IC50 = 12.5μg/ml）、热带假丝酵母变种（IC50 = 25μg/ml）、近平滑假丝酵母（IC50 = 6.25μg/ml）、光滑假丝酵母（IC50 = 6.25μg/ml）、热带假丝酵母（IC50 = 12.5μg/ml）和近平滑假丝酵母（IC50 = 12.5μg/ml）的生物膜形成抑制浓度（IC50）分别为 12.5μg/ml、25μg/ml、6.25μg/ml、6.25μg/ml、12.5μg/ml 和 12.5μg/ml，而对假丝酵母的直接生长没有直接影响。用 6.25μg/ml 的提取物处理后，米康唑的抗真菌敏感性从真菌生长测定中 32%的降低增加到 98.8%。提取物的剂量依赖性降低了假丝酵母的二态性转换，用 3.125μg/ml 的提取物处理完全阻止了假丝酵母对 HaCaT 细胞的黏附。为了了解提取物抑制生物膜形成的分子机制，进行了 qRT-PCR 分析，结果发现提取物呈剂量依赖性降低菌丝相关基因（ALS3、ECE1、HWP1、PGA50 和 PBR1）、细胞外基质基因（GSC1、ZAP1、ADH5 和 CSH1）、Ras1-cAMP-PKA 通路基因（CYR1、EFG1 和 RAS1）、Cph2-Tec1 通路基因（TEC1）和 MAP 激酶通路基因（HST7）的表达。在这项研究中，贯叶连翘提取物显示出抑制真菌生物膜形成、激活抗真菌敏感性和减少感染的作用。这些结果表明，真菌生物膜形成是开发抗真菌佐剂的良好筛选方法，贯叶连翘提取物应该是治疗与生物膜相关的真菌感染的良好候选药物。
