Conn Brittney N, Lieberman Jacob A, Chatman Priscilla, Cotton Kaitlyn, Essandoh Martha A, Ebqa'ai Mohammad, Nelson Toby L, Wozniak Karen L
Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States.
Department of Chemistry, Oklahoma State University, Stillwater, OK, United States.
Front Microbiol. 2024 Jan 16;14:1339303. doi: 10.3389/fmicb.2023.1339303. eCollection 2023.
is an opportunistic fungal pathogen that causes meningitis in >152,000 immunocompromised individuals annually, leading to 112,000 yearly deaths. The four classes of existing antifungal agents target plasma membrane sterols (ergosterol), nucleic acid synthesis, and cell wall synthesis. Existing drugs are not highly effective against , and antifungal drug resistance is an increasing problem. A novel antimicrobial compound, a eumelanin-inspired indoylenepheyleneethynylene, EIPE-1, was synthesized and has antimicrobial activity against Gram-positive bacteria, including methicillin-resistant (MSRA), but not towards Gram-negative organisms. Based on EIPE-1's antibacterial activity, we hypothesized that EIPE-1 could have antifungal activity. For these studies, we tested EIPE-1 against strain H99 and 6 additional cryptococcal clinical isolates. We examined antifungal activity, cytotoxicity, effects on fungal gene expression, and mechanism of action of EIPE-1. Results showed that EIPE-1 has fungicidal effects on seven cryptococcal strains with MICs ranging from 1.56 to 3.125 μg/mL depending on the strain, and it is non-toxic to mammalian cells. We conducted scanning and transmission electron microscopy on the exposed cells to examine structural changes to the organism following EIPE-1 treatment. Cells exposed displayed structural changes to their cell wall and membranes, with internal contents leaking out of the cells. To understand the effect of EIPE-1 on fungal gene expression, RNA sequencing was conducted. Results showed that EIPE-1 affects several processes involved stress response, ergosterol biosynthesis, capsule biosynthesis, and cell wall attachment and remodeling. Therefore, our studies demonstrate that EIPE-1 has antifungal activity against which affects both cellular structure and gene expression of multiple fungal pathways involved in cell membrane stability and viability.
是一种机会性真菌病原体，每年在超过15.2万名免疫功能低下的个体中引起脑膜炎，导致每年11.2万人死亡。现有的四类抗真菌药物靶向质膜甾醇（麦角甾醇）、核酸合成和细胞壁合成。现有药物对 效果不佳，抗真菌耐药性问题日益严重。一种新型抗菌化合物，一种受真黑素启发的吲哚亚苯基乙炔，EIPE-1，已被合成，对包括耐甲氧西林 （MSRA） 在内的革兰氏阳性菌具有抗菌活性，但对革兰氏阴性菌无活性。基于EIPE-1的抗菌活性，我们推测EIPE-1可能具有抗真菌活性。在这些研究中，我们测试了EIPE-1对菌株H99和另外6株隐球菌临床分离株的作用。我们研究了EIPE-1的抗真菌活性、细胞毒性、对真菌基因表达的影响及其作用机制。结果表明，EIPE-1对7株隐球菌菌株具有杀菌作用，MIC值在1.56至3.125μg/mL之间，具体取决于菌株，并且对哺乳动物细胞无毒。我们对暴露的细胞进行了扫描和透射电子显微镜检查，以观察EIPE-1处理后生物体的结构变化。暴露的细胞显示出其细胞壁和细胞膜的结构变化，内部物质从细胞中泄漏出来。为了了解EIPE-1对真菌基因表达的影响，我们进行了RNA测序。结果表明，EIPE-1影响多个过程，包括应激反应、麦角甾醇生物合成、荚膜生物合成以及细胞壁附着和重塑。因此，我们的研究表明，EIPE-1对 具有抗真菌活性，它影响参与细胞膜稳定性和活力的多个真菌途径的细胞结构和基因表达。
