Mechanistic study of the photodynamic inactivation of candida albicans by a cationic porphyrin
Mechanistic study of the photodynamic inactivation of candida albicans by a cationic porphyrin
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DOI：
10.1128/aac.49.5.2026-2034.2005
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发表时间：
2005-05-01
影响因子：
4.9
通讯作者：
Van Marle, J
中科院分区：
文献类型：
--
作者：
Lambrechts, SAG;Aalders, MCG;Van Marle, J
对抗真菌药物的日益增长的耐药性已经重新寻找替代治疗方式，抗菌光动力失活（PDI）是一个潜在的候选。阳离子卟啉5-苯基-10,15,20- tris （n -甲基-4-吡啶基）卟啉氯（TriP[4]）是一种光敏剂，与光结合可以灭活细菌、真菌和病毒。为了进一步提高临床相关真菌（如白色念珠菌）PDI的疗效，我们通过荧光共聚焦显微镜和冷冻断裂电镜观察暴露于PDI的白色念珠菌的反应，试图了解PDI的作用机制。在黑暗条件下观察到以下事件：TriP[4]与白色念珠菌的细胞包膜结合，没有或很少TriP[4]进入细胞。在光照下，细胞膜被破坏，并最终成为可渗透的TriP[4]。在致死性膜损伤后，大量的TriP[4]流入细胞。一旦TriP[4]通过质膜，只有液泡膜能够抵抗pdi诱导的损伤。在光照前增加白色念珠菌与TriP[41]的孵卵时间，并没有增加TriP[41]进入细胞的数量，也没有增加PDI的效果。用10%的PBS代替100%的磷酸盐缓冲盐水（PBS）作为培养基后，白色假丝酵母菌在暗孵育期间对TriP[4]具有渗透性，PDI的效果显著提高。综上所述，阳离子卟啉TriP[4]可成功灭活白色念珠菌，胞质膜为目标细胞器。TriP[41]内流仅在细胞死亡后发生。
The growing resistance against antifungal agents has renewed the search for alternative treatment modalities, and antimicrobial photodynamic inactivation (PDI) is a potential candidate. The cationic porphyrin 5-phenyl-10,15,20-Tris(N-methyl-4-pyridyl)porphyrin chloride (TriP[4]) is a photosensitizer that in combination with light can inactivate bacteria, fungi, and viruses. For future improvement of the efficacy of PDI of clinically relevant fungi such as Candida albicans, we sought to understand the working mechanism by following the response of C albicans exposed to PDI using fluorescence confocal microscopy and freeze-fracture electron microscopy. The following events were observed under dark conditions: TriP[4] binds to the cell envelope of C. albicans, and none or very little TriP[4] enters the cell. Upon illumination the cell membrane is damaged and eventually becomes permeable for TriP[4]. After lethal membrane damage, a massive influx of TriP[4] into the cell occurs. Only the vacuole membrane is resistant to PDI-induced damage once TriP[4] passes the plasma membrane. Increasing the incubation time of C. albicans with TriP[41 prior to illumination did not increase the influx of TriP[41 into the cell or the efficacy of PDI. After the replacement of 100% phosphate-buffered saline (PBS) by 10% PBS as the medium, C. albicans became permeable for TriP[4] during dark incubation and the efficacy of PDI increased dramatically. In conclusion, C. albicans can be successfully inactivated by the cationic porphyrin TriP[4], and the cytoplasmic membrane is the target organelle. TriP[41 influx occurred only after cell death.